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Li X, Tan C, Li P, Lin L, Zhou J, Tao H, Cai Y. Biological Control of Avocado Branch Blight Caused by Lasiodiplodia theobromae Using Bacillus velezensis. PLANT DISEASE 2024; 108:2053-2064. [PMID: 38347735 DOI: 10.1094/pdis-10-23-2216-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/25/2024]
Abstract
In recent years, avocado branch blight has gradually become one of the major diseases causing mortality of avocado trees, which seriously affects the economic development of avocado planting regions. In order to investigate the cause of the disease, the pathogens were isolated from the interroot of avocado trees with the onset of the disease and identified as Lasiodiplodia theobromae. At the same time, three Bacillus velezensis strains, YK194, YK201, and YK268, with better antagonistic effects and high stability against L. theobromae, were isolated from the rhizospheric soil of healthy avocado plants. The results of branch experiments and field trials showed that the avocado leaves as well as branches treated with the strains YK194, YK201, and YK268 did not develop disease, and the incidence of avocado trees was significantly reduced. In the branch experiments, the biological control effect of the strains YK194, YK201, and YK268 reached 62.07, 52.70, and 72.45%, respectively. In the field experiments, it reached 63.85, 63.43, and 73.86%, respectively, which indicated that all these three strains possessed good biological control effects on avocado branch blight. Further investigation on the mechanism of action of antagonistic strains revealed that B. velezensis YK268 could produce lipopeptides, namely, surfactin, fengycin, and iturin, which could significantly inhibit the spore germination of L. theobromae. Consequently, these three isolates have potential as biocontrol agents against L. theobromae.
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Affiliation(s)
- Xiaoyu Li
- College of Natural Resources and Environment, South China Agricultural University, Guangzhou, 510642, China
| | - Chenxing Tan
- National Key Laboratory of Green Pesticide, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Engineering Research Center of Biological Control, Ministry of Education, Integrative Microbiology Research Center, South China Agricultural University, Guangzhou, 510642, China
| | - Ping Li
- College of Natural Resources and Environment, South China Agricultural University, Guangzhou, 510642, China
| | - Lizhen Lin
- College of Natural Resources and Environment, South China Agricultural University, Guangzhou, 510642, China
| | - Jianuan Zhou
- National Key Laboratory of Green Pesticide, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Engineering Research Center of Biological Control, Ministry of Education, Integrative Microbiology Research Center, South China Agricultural University, Guangzhou, 510642, China
| | - Huan Tao
- College of Natural Resources and Environment, South China Agricultural University, Guangzhou, 510642, China
| | - Yanfei Cai
- College of Natural Resources and Environment, South China Agricultural University, Guangzhou, 510642, China
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Wang X, Wang S, Huang M, He Y, Guo S, Yang K, Wang N, Sun T, Yang H, Yang T, Xu Y, Shen Q, Friman VP, Wei Z. Phages enhance both phytopathogen density control and rhizosphere microbiome suppressiveness. mBio 2024; 15:e0301623. [PMID: 38780276 PMCID: PMC11237578 DOI: 10.1128/mbio.03016-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 03/21/2024] [Indexed: 05/25/2024] Open
Abstract
Bacteriophages, viruses that specifically target plant pathogenic bacteria, have emerged as a promising alternative to traditional agrochemicals. However, it remains unclear how phages should be applied to achieve efficient pathogen biocontrol and to what extent their efficacy is shaped by indirect interactions with the resident microbiota. Here, we tested if the phage biocontrol efficacy of Ralstonia solanacearum phytopathogenic bacterium can be improved by increasing the phage cocktail application frequency and if the phage efficacy is affected by pathogen-suppressing bacteria already present in the rhizosphere. We find that increasing phage application frequency improves R. solanacearum density control, leading to a clear reduction in bacterial wilt disease in both greenhouse and field experiments with tomato. The high phage application frequency also increased the diversity of resident rhizosphere microbiota and enriched several bacterial taxa that were associated with the reduction in pathogen densities. Interestingly, these taxa often belonged to Actinobacteria known for antibiotics production and soil suppressiveness. To test if they could have had secondary effects on R. solanacearum biocontrol, we isolated Actinobacteria from Nocardia and Streptomyces genera and tested their suppressiveness to the pathogen in vitro and in planta. We found that these taxa could clearly inhibit R. solanacearum growth and constrain bacterial wilt disease, especially when combined with the phage cocktail. Together, our findings unravel an undiscovered benefit of phage therapy, where phages trigger a second line of defense by the pathogen-suppressing bacteria that already exist in resident microbial communities. IMPORTANCE Ralstonia solanacearum is a highly destructive plant-pathogenic bacterium with the ability to cause bacterial wilt in several crucial crop plants. Given the limitations of conventional chemical control methods, the use of bacterial viruses (phages) has been explored as an alternative biological control strategy. In this study, we show that increasing the phage application frequency can improve the density control of R. solanacearum, leading to a significant reduction in bacterial wilt disease. Furthermore, we found that repeated phage application increased the diversity of rhizosphere microbiota and specifically enriched Actinobacterial taxa that showed synergistic pathogen suppression when combined with phages due to resource and interference competition. Together, our study unravels an undiscovered benefit of phages, where phages trigger a second line of defense by the pathogen-suppressing bacteria present in resident microbial communities. Phage therapies could, hence, potentially be tailored according to host microbiota composition to unlock the pre-existing benefits provided by resident microbiota.
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Affiliation(s)
- Xiaofang Wang
- Jiangsu provincial key lab for solid organic waste utilization, Key lab of organic-based fertilizers of China,Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Shuo Wang
- Jiangsu provincial key lab for solid organic waste utilization, Key lab of organic-based fertilizers of China,Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Mingcong Huang
- Jiangsu provincial key lab for solid organic waste utilization, Key lab of organic-based fertilizers of China,Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Yilin He
- Jiangsu provincial key lab for solid organic waste utilization, Key lab of organic-based fertilizers of China,Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Saisai Guo
- Jiangsu provincial key lab for solid organic waste utilization, Key lab of organic-based fertilizers of China,Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Keming Yang
- Jiangsu provincial key lab for solid organic waste utilization, Key lab of organic-based fertilizers of China,Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, China
- College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Ningqi Wang
- Jiangsu provincial key lab for solid organic waste utilization, Key lab of organic-based fertilizers of China,Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Tianyu Sun
- Jiangsu provincial key lab for solid organic waste utilization, Key lab of organic-based fertilizers of China,Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Hongwu Yang
- China National Tobacco Corporation Hunan Company, Changsha, Hunan, China
| | - Tianjie Yang
- Jiangsu provincial key lab for solid organic waste utilization, Key lab of organic-based fertilizers of China,Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Yangchun Xu
- Jiangsu provincial key lab for solid organic waste utilization, Key lab of organic-based fertilizers of China,Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Qirong Shen
- Jiangsu provincial key lab for solid organic waste utilization, Key lab of organic-based fertilizers of China,Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Ville-Petri Friman
- Jiangsu provincial key lab for solid organic waste utilization, Key lab of organic-based fertilizers of China,Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, China
- Department of Microbiology, University of Helsinki, Helsinki, Finland
| | - Zhong Wei
- Jiangsu provincial key lab for solid organic waste utilization, Key lab of organic-based fertilizers of China,Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, China
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Bhatt S, Faridi N, Raj SMP, Agarwal A, Punetha M. Recent advances in immuno-based methods for the detection of Ralstonia solanacearum. J Microbiol Methods 2024; 217-218:106889. [PMID: 38211840 DOI: 10.1016/j.mimet.2024.106889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 01/08/2024] [Accepted: 01/08/2024] [Indexed: 01/13/2024]
Abstract
Ralstonia solanacearum (RS) is a widely recognized phytopathogenic bacterium which is responsible for causing devastating losses in a wide range of economically significant crops. Timely and accurate detection of this pathogen is pivotal to implementing effective disease management strategies and preventing crop losses. This review provides a comprehensive overview of recent advances in immuno-based detection methods for RS. The review begins by introducing RS, highlighting its destructive potential and the need for point-of-care detection techniques. Subsequently, it explores traditional detection methods and their limitations, emphasizing the need for innovative approaches. The main focus of this review is on immuno-based detection methods and it discusses recent advancements in serological detection techniques. Furthermore, the review sheds light on the challenges and prospects of immuno-based detection of RS. It emphasizes the importance of developing rapid, field-deployable assays that can be used by farmers and researchers alike. In conclusion, this review provides valuable insights into the recent advances in immuno-based detection methods for RS.
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Affiliation(s)
- Shalini Bhatt
- P P Savani University, Surat 394125, Gujarat, India; Defence Institute of Bio-Energy Research (DIBER), DRDO, Nainital, Haldwani 263139, Uttarakhand, India.
| | - Neha Faridi
- Defence Institute of Bio-Energy Research (DIBER), DRDO, Nainital, Haldwani 263139, Uttarakhand, India
| | - S Merwyn P Raj
- Defence Institute of Bio-Energy Research (DIBER), DRDO, Nainital, Haldwani 263139, Uttarakhand, India
| | - Ankur Agarwal
- Defence Institute of Bio-Energy Research (DIBER), DRDO, Nainital, Haldwani 263139, Uttarakhand, India
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Ren X, Zhou J, Liu T, Zhong C, Wang Y, Yan H, Feng J. Antibacterial activity and action mechanism of curcusionol from Carex siderosticta Hance against Ralstonia nicotianae. PEST MANAGEMENT SCIENCE 2023; 79:4607-4616. [PMID: 37436717 DOI: 10.1002/ps.7661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 06/30/2023] [Accepted: 07/12/2023] [Indexed: 07/13/2023]
Abstract
BACKGROUND Tobacco bacterial wilt is a typical soil-borne disease caused by Ralstonia nicotianae, which causes huge losses in tobacco production every year. The crude extract of Carex siderosticta Hance was shown to have antibacterial activity against R. nicotianae during our search, and the natural antibacterial components were sought after using bioassay-guided fractionation of the compounds. RESULT Ethanol extract of Carex siderosticta Hance with the minimum inhibitory concentration (MIC) value of 100 μg/mL against R. nicotianae in vitro. The potential of these compounds as antibactericides against R. nicotianae were assessed. Curcusionol (1), showed the highest antibacterial activity against R. nicotianae with MIC value of 12.5 μg/mL in vitro. In the protective effect tests, the control effect of curcusionol (1) was 92.31 and 72.60%, respectively, after application of 7 and 14 days, at a concentration of 1500 μg/mL, being comparable to that of streptomycin sulfate at a concentration of 500 μg/mL, confirming that curcusionol (1) showed the potential for the development of new antibacterial drugs. RNA-sequencing, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis confirmed that curcusionol mainly destroys R. nicotianae cell membrane structure and affects quorum sensing (QS) to inhibit pathogenic bacteria. CONCLUSION This study revealed that the antibacterial activity of Carex siderosticta Hance makes it a botanical bactericide against R. nicotianae, while curcusionol as lead structures for antibacterial development is obvious by its potent antibacterial activity. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Xingyu Ren
- College of Plant Protection, Northwest A&F University, Xianyang, China
- Provincial Center for Bio-Pesticide Engineering, Northwest A&F University, Xianyang, China
| | - Juan Zhou
- College of Plant Protection, Northwest A&F University, Xianyang, China
- Provincial Center for Bio-Pesticide Engineering, Northwest A&F University, Xianyang, China
| | - Ting Liu
- College of Plant Protection, Northwest A&F University, Xianyang, China
- Provincial Center for Bio-Pesticide Engineering, Northwest A&F University, Xianyang, China
| | - Chenquan Zhong
- College of Plant Protection, Northwest A&F University, Xianyang, China
- Provincial Center for Bio-Pesticide Engineering, Northwest A&F University, Xianyang, China
| | - Yong Wang
- College of Plant Protection, Northwest A&F University, Xianyang, China
- Provincial Center for Bio-Pesticide Engineering, Northwest A&F University, Xianyang, China
| | - He Yan
- College of Plant Protection, Northwest A&F University, Xianyang, China
- Provincial Center for Bio-Pesticide Engineering, Northwest A&F University, Xianyang, China
| | - Juntao Feng
- College of Plant Protection, Northwest A&F University, Xianyang, China
- Provincial Center for Bio-Pesticide Engineering, Northwest A&F University, Xianyang, China
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Liu Q, Li C, Zhang X, Ding M, Liao X, Yan J, Hu M, Yang L, Wang X, Liao L, Li P, Zhou X. PhcX Is a LqsR-family response regulator that contributes to Ralstonia solanacearum virulence and regulates multiple virulence factors. mBio 2023; 14:e0202823. [PMID: 37787568 PMCID: PMC10653808 DOI: 10.1128/mbio.02028-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 08/15/2023] [Indexed: 10/04/2023] Open
Abstract
IMPORTANCE The bacterial wilt caused by the soil-borne phytopathogen Ralstonia solanacearum is one of the most destructive crop diseases. To achieve a successful infection, R. solanacearum has evolved an intricate regulatory network to orchestrate the expression of an arsenal of virulence factors and fine-tune the allocation of energy. However, despite the wealth of knowledge gained in the past decades, many players and connections are still missing from the network. The importance of our study lies in the identification of PhcX, a novel conserved global regulator with critical roles in modulating the virulence and metabolism of R. solanacearum. PhcX affects many well-characterized regulators and exhibits contrasting modes of regulation from the central regulator PhcA on a variety of virulence-associated traits and genes. Our findings add a valuable piece to the puzzle of how the pathogen regulates its proliferation and infection, which is critical for understanding its pathogenesis and developing disease control strategies.
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Affiliation(s)
- Qingmei Liu
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Chuhao Li
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Xiaohan Zhang
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Mengfan Ding
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Xinyue Liao
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Jinli Yan
- School of Agricultural Science, Xichang University, Xichang, China
| | - Ming Hu
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Leilei Yang
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Xiaoqing Wang
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Lisheng Liao
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Peng Li
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Hainan Provincial Key Laboratory for Tropical Plant and Animal Ecology, College of Life Sciences, Hainan Normal University, Haikou, China
| | - Xiaofan Zhou
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
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Tahir HAS, Ali Q, Rajer FU, Shakeel Q, Gillani W, Binyamin R, Tayyab HMA, Khan AR, Gu Q, Gao X, Wu H. Transcriptomic analysis of Ralstonia solanacearum in response to antibacterial volatiles of Bacillus velezensis FZB42. Arch Microbiol 2023; 205:358. [PMID: 37878074 DOI: 10.1007/s00203-023-03697-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 09/26/2023] [Accepted: 10/01/2023] [Indexed: 10/26/2023]
Abstract
Volatile organic compounds (VOCs), produced by a variety of microbial species and used as biological agents, have been demonstrated to play a significant role in controlling phytopathogens. In continuation of our previous studies, we aim to elucidate the underlying mechanisms and pathways involved in interactions between pathogens and microbial VOCs. In the current study, we tested how VOCs produced by Bacillus velezensis FZB42 affect the growth of Ralstonia solanacearum TBBS1 in vitro.Query The result showed that the colony growth of R. solanacearum was reduced with an inhibition rate of 0.83 ± 0.043 as compared to the control 1.7 ± 0.076, respectively. The number of viable cells of R. solanacearum was significantly decreased to 7.68 CFU/mL as compared to the control (9.02 CFU/mL). In addition, transcriptomic analysis of R. solanacearum in response to VOCs produced by FZB42 was performed to better understand the effect of VOCs on R. solanacearum. The transcriptional response of R. solanacearum to FZB42-VOCs was determined using an Illumina RNA-seq approach. The results revealed significant changes in the expression of 2094 R. solanacearum genes, including 593 upregulated and 1501 downregulated genes. To validate the RNA-seq results, the expression of 10 genes was quantified using RT-qPCR. Furthermore, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases were used to functionally annotate differentially expressed genes. Significant changes were observed in genes directly or indirectly related to virulence, including those related to bacterial invasion, motility, chemotaxis, and secretion systems. Overall, RNA-seq profiling provides new insights into the possible fundamental molecular mechanisms that are responsible for the reduction in growth and virulence of R. solanacearum upon application of FZB42-VOC.
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Affiliation(s)
- Hafiz Abdul Samad Tahir
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
- Pakistan Tobacco Board, Ministry of National Food Security and Research, Peshawar, Pakistan
| | - Qurban Ali
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Faheem Uddin Rajer
- Department of Plant Pathology, Faculty of Crop Protection, Sindh Agriculture University, Tandojam, 70060, Pakistan
| | - Qaisar Shakeel
- Department of Plant Pathology, The Islamia University of Bahawalpur, Bahawalpur, Punjab, Pakistan
| | - Waqqas Gillani
- Pakistan Tobacco Board, Ministry of National Food Security and Research, Peshawar, Pakistan
| | - Rana Binyamin
- Muhammad Nawaz Sharif University of Agriculture, Multan, Pakistan
| | | | - Abdur Rashid Khan
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Qin Gu
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Xuewen Gao
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Huijun Wu
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
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Yang K, Fu R, Feng H, Jiang G, Finkel O, Sun T, Liu M, Huang B, Li S, Wang X, Yang T, Wang Y, Wang S, Xu Y, Shen Q, Friman VP, Jousset A, Wei Z. RIN enhances plant disease resistance via root exudate-mediated assembly of disease-suppressive rhizosphere microbiota. MOLECULAR PLANT 2023; 16:1379-1395. [PMID: 37563832 DOI: 10.1016/j.molp.2023.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 05/06/2023] [Accepted: 08/07/2023] [Indexed: 08/12/2023]
Abstract
The RIPENING-INHIBITOR (RIN) transcriptional factor is a key regulator governing fruit ripening. While RIN also affects other physiological processes, its potential roles in triggering interactions with the rhizosphere microbiome and plant health are unknown. Here we show that RIN affects microbiome-mediated disease resistance via root exudation, leading to recruitment of microbiota that suppress the soil-borne, phytopathogenic Ralstonia solanacearum bacterium. Compared with the wild-type (WT) plant, RIN mutants had different root exudate profiles, which were associated with distinct changes in microbiome composition and diversity. Specifically, the relative abundances of antibiosis-associated genes and pathogen-suppressing Actinobacteria (Streptomyces) were clearly lower in the rhizosphere of rin mutants. The composition, diversity, and suppressiveness of rin plant microbiomes could be restored by the application of 3-hydroxyflavone and riboflavin, which were exuded in much lower concentrations by the rin mutant. Interestingly, RIN-mediated effects on root exudates, Actinobacteria, and disease suppression were evident from the seedling stage, indicating that RIN plays a dual role in the early assembly of disease-suppressive microbiota and late fruit development. Collectively, our work suggests that, while plant disease resistance is a complex trait driven by interactions between the plant, rhizosphere microbiome, and the pathogen, it can be indirectly manipulated using "prebiotic" compounds that promote the recruitment of disease-suppressive microbiota.
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Affiliation(s)
- Keming Yang
- Key Lab of Organic-based Fertilizers of China, Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China; College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Ruixin Fu
- Key Lab of Organic-based Fertilizers of China, Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China; School of Biology and Food, Shangqiu Normal University, Shangqiu 476000, China
| | - Haichao Feng
- College of Agriculture, Henan University, Zhengzhou 450046, China
| | - Gaofei Jiang
- Key Lab of Organic-based Fertilizers of China, Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Omri Finkel
- Department of Plant and Environmental Sciences, Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tianyu Sun
- Key Lab of Organic-based Fertilizers of China, Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Mingchun Liu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China
| | - Baowen Huang
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing, China
| | - Shan Li
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China
| | - Xiaofang Wang
- Key Lab of Organic-based Fertilizers of China, Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Tianjie Yang
- Key Lab of Organic-based Fertilizers of China, Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
| | - Yikui Wang
- Institute of Vegetable Research, Guangxi Academy of Agricultural Sciences, Nanning, China.
| | - Shimei Wang
- Key Lab of Organic-based Fertilizers of China, Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Yangchun Xu
- Key Lab of Organic-based Fertilizers of China, Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Qirong Shen
- Key Lab of Organic-based Fertilizers of China, Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Ville-Petri Friman
- Key Lab of Organic-based Fertilizers of China, Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China; Department of Biology, University of York, York YO10 5DD, UK; Department of Microbiology, University of Helsinki, 00014 Helsinki, Finland
| | - Alexandre Jousset
- Key Lab of Organic-based Fertilizers of China, Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Zhong Wei
- Key Lab of Organic-based Fertilizers of China, Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
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8
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Cho SY, Oh HB, Yoon SI. Hexameric structure of the flagellar master regulator FlhDC from Cupriavidus necator and its interaction with flagellar promoter DNA. Biochem Biophys Res Commun 2023; 672:97-102. [PMID: 37343320 DOI: 10.1016/j.bbrc.2023.06.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 06/09/2023] [Indexed: 06/23/2023]
Abstract
Bacterial flagella are assembled with ∼30 different proteins in a defined order via diverse regulatory systems. In gram-negative bacteria from the Gammaproteobacteria and Betaproteobacteria classes, the transcription of flagellar genes is strictly controlled by the master regulator FlhDC. In Gammaproteobacteria species, the FlhDC complex has been shown to activate flagellar expression by directly interacting with the promoter region in flagellar genes. To obtain the DNA-binding mechanism of FlhDC and determine the conserved and distinct structural features of Betaproteobacteria and Gammaproteobacteria FlhDCs that are necessary for their functions, we determined the crystal structure of Betaproteobacteria Cupriavidus necator FlhDC (cnFlhDC) and biochemically analyzed its DNA-binding capacity. cnFlhDC specifically recognized the promoter DNA of the class II flagellar genes flgB and flhB. cnFlhDC adopts a ring-like heterohexameric structure (cnFlhD4C2) and harbors two Zn-Cys clusters, as observed for Gammaproteobacteria Escherichia coli FlhDC (ecFlhDC). The cnFlhDC structure exhibits positively charged surfaces across two FlhDC subunits as a putative DNA-binding site. Noticeably, the positive patch of cnFlhDC is continuous, in contrast to the separated patches of ecFlhDC. Moreover, the ternary intersection of cnFlhD4C2 behind the Zn-Cys cluster forms a unique protruding neutral structure, which is replaced with a charged cavity in the ecFlhDC structure.
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Affiliation(s)
- So Yeon Cho
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Han Byeol Oh
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Sung-Il Yoon
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, 24341, Republic of Korea.
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9
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Schiavi D, Ronchetti R, Di Lorenzo V, Vivani R, Giovagnoli S, Camaioni E, Balestra GM. Sustainable Protocols for Cellulose Nanocrystals Synthesis from Tomato Waste and Their Antimicrobial Properties against Pseudomonas syringae pv. tomato. PLANTS (BASEL, SWITZERLAND) 2023; 12:plants12040939. [PMID: 36840287 PMCID: PMC9963933 DOI: 10.3390/plants12040939] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/15/2023] [Accepted: 02/15/2023] [Indexed: 06/12/2023]
Abstract
Nanotechnology is rapidly gaining ground in crop protection, with the growing quest for sustainable nanopesticides and nanocarriers for plant pathogen management. Among them, cellulose nanocrystals (CNC) are emerging as innovative agrofood-waste-derived antimicrobial materials. In this work, new chemical and enzymatic CNC extraction methods from tomato harvest residues were evaluated. The obtained nanomaterials were characterized and tested for their antimicrobial properties on Pseudomonas syringae pv. tomato (Pto), the causal agent of bacterial speck disease on tomato. Both protocols were efficient. The enzymatic extraction method was greener, producing purer CNC at slightly lower yield. The obtained CNC, although they weakly inhibited cell growth and did not promote reactive oxygen species (ROS) formation, provoked bacterial aggregation and the inhibition of biofilm production and swimming motility. Both protocols produced CNC with similar morpho-chemical features, as well as promising antimicrobial activity against plant bacterial pathogens, suggesting their potential role in sustainable crop protection strategies. The new protocols could be a valuable alternative to conventional methods.
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Affiliation(s)
- Daniele Schiavi
- Department of Agriculture and Forest Sciences (DAFNE), University of Tuscia, Via San Camillo de Lellis snc, 01100 Viterbo, Italy
| | - Riccardo Ronchetti
- Department of Pharmaceutical Sciences (DSF), University of Perugia, Via del Liceo 1, 06123 Perugia, Italy
| | - Veronica Di Lorenzo
- Department of Agriculture and Forest Sciences (DAFNE), University of Tuscia, Via San Camillo de Lellis snc, 01100 Viterbo, Italy
| | - Riccardo Vivani
- Department of Pharmaceutical Sciences (DSF), University of Perugia, Via del Liceo 1, 06123 Perugia, Italy
| | - Stefano Giovagnoli
- Department of Pharmaceutical Sciences (DSF), University of Perugia, Via del Liceo 1, 06123 Perugia, Italy
| | - Emidio Camaioni
- Department of Pharmaceutical Sciences (DSF), University of Perugia, Via del Liceo 1, 06123 Perugia, Italy
| | - Giorgio M. Balestra
- Department of Agriculture and Forest Sciences (DAFNE), University of Tuscia, Via San Camillo de Lellis snc, 01100 Viterbo, Italy
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10
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Wen D, Guo Q, Zhao W, Yang Y, Yang C, Yu J, Hu Y. Effect and mechanism of NaHS on tobacco bacterial wilt caused by Ralstonia solanacearum. Sci Rep 2023; 13:2462. [PMID: 36774417 PMCID: PMC9922318 DOI: 10.1038/s41598-022-26697-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 12/19/2022] [Indexed: 02/13/2023] Open
Abstract
Since its discovery as a third unique gaseous signal molecule, hydrogen sulfide (H2S) has been extensively employed to resist stress and control pathogens. Nevertheless, whether H2S can prevent tobacco bacterial wilt is unknown yet. We evaluated the impacts of the H2S donor sodium hydrosulfide (NaHS) on the antibacterial activity, morphology, biofilm, and transcriptome of R. solanacearum to understand the effect and mechanism of NaHS on tobacco bacterial wilt. In vitro, NaHS significantly inhibited the growth of Ralstonia solanacearum and obviously altered its cell morphology. Additionally, NaHS significantly inhibited the biofilm formation and swarming motility of R. solanacearum, and reduced the population of R. solanacearum invading tobacco roots. In field experiments, the application of NaHS dramatically decreased the disease incidence and index of tobacco bacterial wilt, with a control efficiency of up to 89.49%. The application of NaHS also influenced the diversity and structure of the soil microbial community. Furthermore, NaHS markedly increased the relative abundances of beneficial microorganisms, which helps prevent tobacco bacterial wilt. These findings highlight NaHS's potential and efficacy as a powerful antibacterial agent for preventing tobacco bacterial wilt caused by R. solanacearum.
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Affiliation(s)
- Dingxin Wen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, College of Life Science, Hubei University, Wuhan, 430062, China
| | - Qingqing Guo
- State Key Laboratory of Biocatalysis and Enzyme Engineering, College of Life Science, Hubei University, Wuhan, 430062, China
| | - Wan Zhao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, College of Life Science, Hubei University, Wuhan, 430062, China
| | - Yong Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, College of Life Science, Hubei University, Wuhan, 430062, China
| | - Chunlei Yang
- Tobacco Research Institute of Hubei Province, Wuhan, 430030, Hubei, China.
| | - Jun Yu
- Tobacco Research Institute of Hubei Province, Wuhan, 430030, Hubei, China.
| | - Yun Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, College of Life Science, Hubei University, Wuhan, 430062, China.
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11
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Xia M, Yu D, Chen H, Dai J, Gao N, Li S, Bi X, Qiu D. An RpoN-dependent PEP-CTERM gene is involved in floc formation of an Aquincola tertiaricarbonis strain. BMC Microbiol 2023; 23:20. [PMID: 36658495 PMCID: PMC9850573 DOI: 10.1186/s12866-022-02745-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 12/21/2022] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND The floc is a characteristic of microbial aggregate growth, displaying cloudy suspensions in water. Floc formation has been demonstrated in a series of bacteria and the floc-forming bacteria play a crucial role in activated sludge (AS) process widely used for municipal sewage and industrial wastewater treatment over a century. It has been demonstrated that some exopolysaccharide biosynthesis genes and the sigma factor (sigma54 or rpoN) were required for floc forming in some bacteria. However, the mechanism underlying the floc formation stills need to be elucidated. RESULTS In this study, we demonstrate that a TPR (Tetratricopeptide repeats) protein-encoding gene prsT is required for floc formation of Aquincola tertiaricarbonis RN12 and an upstream PEP-CTERM gene (designated pepA), regulated by RpoN1, is involved in its floc formation but not swarming motility and biofilm formation. Overexpression of PepA could rescue the floc-forming phenotype of the rpoN1 mutant by decreasing the released soluble exopolysaccharides and increasing the bound polymers. CONCLUSION Our results indicate that the wide-spread PEP-CTERM proteins play an important role in the self-flocculation of bacterial cells and may be a component of extracellular polymeric substances required for floc-formation.
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Affiliation(s)
- Ming Xia
- grid.411854.d0000 0001 0709 0000School of Life Sciences, Hubei Engineering Research Center for Protection and Utilization of Special Biological Resources in the Hanjiang River Basin, Jianghan University, Wuhan, 430056 China ,grid.411854.d0000 0001 0709 0000Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, Jianghan University, Wuhan, 430056 China
| | - Dianzhen Yu
- grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, 100049 China ,grid.419092.70000 0004 0467 2285Institute for Nutritional Sciences, SIBS, Chinese Academy of Sciences, Shanghai, 200031 China
| | - Han Chen
- grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, 100049 China ,grid.429211.d0000 0004 1792 6029Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 Hubei Province China
| | - Jingcheng Dai
- grid.429211.d0000 0004 1792 6029Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 Hubei Province China
| | - Na Gao
- grid.469521.d0000 0004 1756 0127Fisheries Research Institute, Anhui Academy of Agricultural Sciences, Hefei, 230031 China
| | - Shuyang Li
- grid.429211.d0000 0004 1792 6029Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 Hubei Province China
| | - Xuezhi Bi
- grid.452198.30000 0004 0485 9218Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore, 138668 Singapore
| | - Dongru Qiu
- grid.429211.d0000 0004 1792 6029Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 Hubei Province China
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12
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Rivera-Zuluaga K, Hiles R, Barua P, Caldwell D, Iyer-Pascuzzi AS. Getting to the root of Ralstonia invasion. Semin Cell Dev Biol 2022; 148-149:3-12. [PMID: 36526528 DOI: 10.1016/j.semcdb.2022.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/01/2022] [Accepted: 12/05/2022] [Indexed: 12/16/2022]
Abstract
Plant diseases caused by soilborne pathogens are a major limiting factor in crop production. Bacterial wilt disease, caused by soilborne bacteria in the Ralstonia solanacearum Species Complex (Ralstonia), results in significant crop loss throughout the world. Ralstonia invades root systems and colonizes plant xylem, changing plant physiology and ultimately causing plant wilting in susceptible varieties. Elucidating how Ralstonia invades and colonizes plants is central to developing strategies for crop protection. Here we review Ralstonia pathogenesis from root detection and attachment, early root colonization, xylem invasion and subsequent wilting. We focus primarily on studies in tomato from the last 5-10 years. Recent work has identified elegant mechanisms Ralstonia uses to adapt to the plant xylem, and has discovered new genes that function in Ralstonia fitness in planta. A picture is emerging of an amazingly versatile pathogen that uses multiple strategies to make its surrounding environment more hospitable and can adapt to new environments.
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13
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Park J, Jung H, Mannaa M, Lee SY, Lee HH, Kim N, Han G, Park DS, Lee SW, Lee SW, Seo YS. Genome-guided comparative in planta transcriptome analyses for identifying cross-species common virulence factors in bacterial phytopathogens. FRONTIERS IN PLANT SCIENCE 2022; 13:1030720. [PMID: 36466249 PMCID: PMC9709210 DOI: 10.3389/fpls.2022.1030720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 10/31/2022] [Indexed: 06/17/2023]
Abstract
Plant bacterial disease is a complex outcome achieved through a combination of virulence factors that are activated during infection. However, the common virulence factors across diverse plant pathogens are largely uncharacterized. Here, we established a pan-genome shared across the following plant pathogens: Burkholderia glumae, Ralstonia solanacearum, and Xanthomonas oryzae pv. oryzae. By overlaying in planta transcriptomes onto the pan-genome, we investigated the expression profiles of common genes during infection. We found over 70% of identical patterns for genes commonly expressed by the pathogens in different plant hosts or infection sites. Co-expression patterns revealed the activation of a signal transduction cascade to recognize and respond to external changes within hosts. Using mutagenesis, we uncovered a relationship between bacterial virulence and functions highly conserved and shared in the studied genomes of the bacterial phytopathogens, including flagellar biosynthesis protein, C4-dicarboxylate ABC transporter, 2-methylisocitrate lyase, and protocatechuate 3,4-dioxygenase (PCD). In particular, the disruption of PCD gene led to attenuated virulence in all pathogens and significantly affected phytotoxin production in B. glumae. This PCD gene was ubiquitously distributed in most plant pathogens with high homology. In conclusion, our results provide cross-species in planta models for identifying common virulence factors, which can be useful for the protection of crops against diverse pathogens.
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Affiliation(s)
- Jungwook Park
- Department of Integrated Biological Science, Pusan National University, Busan, South Korea
- Biotechnology Research Division, National Institute of Fisheries Science, Busan, South Korea
| | - Hyejung Jung
- Department of Integrated Biological Science, Pusan National University, Busan, South Korea
| | - Mohamed Mannaa
- Department of Integrated Biological Science, Pusan National University, Busan, South Korea
| | - Seung Yeup Lee
- Department of Applied Bioscience, Dong-A University, Busan, South Korea
| | - Hyun-Hee Lee
- Department of Integrated Biological Science, Pusan National University, Busan, South Korea
| | - Namgyu Kim
- Department of Integrated Biological Science, Pusan National University, Busan, South Korea
| | - Gil Han
- Department of Integrated Biological Science, Pusan National University, Busan, South Korea
| | - Dong-Soo Park
- Paddy Crop Division, National Institute of Crop Science, Rural Development Administration, Miryang, South Korea
| | - Sang-Won Lee
- Department of Plant Molecular Systems Biotech & Crop Biotech Institute, KyungHee University, Yongin, South Korea
| | - Seon-Woo Lee
- Department of Applied Bioscience, Dong-A University, Busan, South Korea
| | - Young-Su Seo
- Department of Integrated Biological Science, Pusan National University, Busan, South Korea
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14
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Lipid-rich endo-metabolites from a vertically transmitted fungal endophyte Penicillium sp. PM031 attenuate virulence factors of phytopathogenic Ralstonia solanacearum. Microbiol Res 2022; 261:127058. [DOI: 10.1016/j.micres.2022.127058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 04/15/2022] [Accepted: 05/01/2022] [Indexed: 11/19/2022]
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15
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Liu Y, Tan X, Pan Y, Yu J, Du Y, Liu X, Ding W. Mutation in phcA Enhanced the Adaptation of Ralstonia solanacearum to Long-Term Acid Stress. Front Microbiol 2022; 13:829719. [PMID: 35722283 PMCID: PMC9204249 DOI: 10.3389/fmicb.2022.829719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 05/03/2022] [Indexed: 11/13/2022] Open
Abstract
Bacterial wilt, caused by the plant pathogen Ralstonia solanacearum, occurs more severely in acidified soil according to previous reports. However, R. solanacearum cannot grow well in acidic environments under barren nutrient culture conditions, especially when the pH is lower than 5. With the worsening acidification of farmland, further determination of how R. solanacearum adapts to the long-term acidic environment is worthwhile. In this study, experimental evolution was applied to evaluate the adaptability and mechanism of the R. solanacearum experimental population responding to long-term acid stress. We chose the CQPS-1 strain as the ancestor, and minimal medium (MM medium) with different pH values as the culture environment to simulate poor soil. After 1500 generations of serial passage experiments in pH 4.9 MM, acid-adapted experimental strains (denoted as C49 strains) were obtained, showing significantly higher growth rates than the growth rates of control experimental strains (serial passage experiment in pH 6.5 MM, denoted as C65 strains). Competition experiments showed that the competitive indices (CIs) of all selected clones from C49 strains were superior to the ancestor in acidic environment competitiveness. Based on the genome variation analysis and functional verification, we confirmed that loss of function in the phcA gene was associated with the acid fitness gain of R. solanacearum, which meant that the inactivation of the PhcA regulator caused by gene mutation mediated the population expansion of R. solanacearum when growing in an acidic stress environment. Moreover, the swimming motility of acid evolution strains and the phcA deletion mutant was significantly enhanced compared to CQPS-1. This work provided evidence for understanding the adaptive strategy of R. solanacearum to the long-term acidic environment.
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Affiliation(s)
- Ying Liu
- College of Plant Protection, Southwest University, Chongqing, China
| | - Xi Tan
- College of Plant Protection, Southwest University, Chongqing, China
| | - Yanxin Pan
- College of Plant Protection, Southwest University, Chongqing, China
| | - Jiamin Yu
- Sichuan Company of China National Tobacco Corporation, Chengdu, China
| | - Yiran Du
- College of Plant Protection, Southwest University, Chongqing, China
| | - Xiaojiao Liu
- College of Plant Protection, Southwest University, Chongqing, China
| | - Wei Ding
- College of Plant Protection, Southwest University, Chongqing, China
- *Correspondence: Wei Ding,
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16
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Geng R, Cheng L, Cao C, Liu Z, Liu D, Xiao Z, Wu X, Huang Z, Feng Q, Luo C, Chen Z, Zhang Z, Jiang C, Ren M, Yang A. Comprehensive Analysis Reveals the Genetic and Pathogenic Diversity of Ralstonia solanacearum Species Complex and Benefits Its Taxonomic Classification. Front Microbiol 2022; 13:854792. [PMID: 35602040 PMCID: PMC9121018 DOI: 10.3389/fmicb.2022.854792] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 04/22/2022] [Indexed: 11/23/2022] Open
Abstract
Ralstonia solanacearum species complex (RSSC) is a diverse group of plant pathogens that attack a wide range of hosts and cause devastating losses worldwide. In this study, we conducted a comprehensive analysis of 131 RSSC strains to detect their genetic diversity, pathogenicity, and evolution dynamics. Average nucleotide identity analysis was performed to explore the genomic relatedness among these strains, and finally obtained an open pangenome with 32,961 gene families. To better understand the diverse evolution and pathogenicity, we also conducted a series of analyses of virulence factors (VFs) and horizontal gene transfer (HGT) in the pangenome and at the single genome level. The distribution of VFs and mobile genetic elements (MGEs) showed significant differences among different groups and strains, which were consistent with the new nomenclatures of the RSSC with three distinct species. Further functional analysis showed that most HGT events conferred from Burkholderiales and played a great role in shaping the genomic plasticity and genetic diversity of RSSC genomes. Our work provides insights into the genetic polymorphism, evolution dynamics, and pathogenetic variety of RSSC and provides strong supports for the new taxonomic classification, as well as abundant resources for studying host specificity and pathogen emergence.
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Affiliation(s)
- Ruimei Geng
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Lirui Cheng
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Changdai Cao
- Shandong Rizhao Tobacco Company Ltd., Rizhao, China
| | - Zhengwen Liu
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Dan Liu
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Zhiliang Xiao
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Xiuming Wu
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Zhenrui Huang
- Key Laboratory of Crop Genetic Improvement, Engineering and Technology Research Center for Tobacco Breeding and Comprehensive Utilization of Guangdong, Crops Research Institute of Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Quanfu Feng
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Chenggang Luo
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Zhiqiang Chen
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Zhenchen Zhang
- Key Laboratory of Crop Genetic Improvement, Engineering and Technology Research Center for Tobacco Breeding and Comprehensive Utilization of Guangdong, Crops Research Institute of Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Caihong Jiang
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Min Ren
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
- *Correspondence: Min Ren,
| | - Aiguo Yang
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
- Aiguo Yang,
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17
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Li M, Pommier T, Yin Y, Wang J, Gu S, Jousset A, Keuskamp J, Wang H, Wei Z, Xu Y, Shen Q, Kowalchuk GA. Indirect reduction of Ralstonia solanacearum via pathogen helper inhibition. THE ISME JOURNAL 2022; 16:868-875. [PMID: 34671104 PMCID: PMC8857195 DOI: 10.1038/s41396-021-01126-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 09/02/2021] [Accepted: 09/20/2021] [Indexed: 11/26/2022]
Abstract
The rhizosphere microbiome forms a first line of defense against soilborne pathogens. To date, most microbiome enhancement strategies have relied on bioaugmentation with antagonistic microorganisms that directly inhibit pathogens. Previous studies have shown that some root-associated bacteria are able to facilitate pathogen growth. We therefore hypothesized that inhibiting such pathogen helpers may help reduce pathogen densities. We examined tripartite interactions between a model pathogen, Ralstonia solanacearum, two model helper strains and a collection of 46 bacterial isolates recovered from the tomato rhizosphere. This system allowed us to examine the importance of direct (effects of rhizobacteria on pathogen growth) and indirect (effects of rhizobacteria on helper growth) pathways affecting pathogen growth. We found that the interaction between rhizosphere isolates and the helper strains was the major determinant of pathogen suppression both in vitro and in vivo. We therefore propose that controlling microbiome composition to prevent the growth of pathogen helpers may become part of sustainable strategies for pathogen control.
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Affiliation(s)
- Mei Li
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Key Lab of Plant Immunity, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, 210095, Nanjing, PR China
- Institute for Environmental Biology, Ecology & Biodiversity, Utrecht University, Padualaan 8, 3584CH, Utrecht, The Netherlands
| | - Thomas Pommier
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, F-69622, Villeurbanne, France
| | - Yue Yin
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Key Lab of Plant Immunity, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, 210095, Nanjing, PR China
| | - Jianing Wang
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Key Lab of Plant Immunity, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, 210095, Nanjing, PR China
| | - Shaohua Gu
- Center for Quantitative Biology and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, PR China
| | - Alexandre Jousset
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Key Lab of Plant Immunity, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, 210095, Nanjing, PR China
| | - Joost Keuskamp
- Institute for Environmental Biology, Ecology & Biodiversity, Utrecht University, Padualaan 8, 3584CH, Utrecht, The Netherlands
- Biont Research, Abeelstraat 33, 3552 RC, Utrecht, The Netherlands
| | - Honggui Wang
- School of Environmental Science and Engineering, Yangzhou University, 225127, Yangzhou, Jiangsu, PR China
| | - Zhong Wei
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Key Lab of Plant Immunity, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, 210095, Nanjing, PR China.
| | - Yangchun Xu
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Key Lab of Plant Immunity, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, 210095, Nanjing, PR China
| | - Qirong Shen
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Key Lab of Plant Immunity, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, 210095, Nanjing, PR China
| | - George A Kowalchuk
- Institute for Environmental Biology, Ecology & Biodiversity, Utrecht University, Padualaan 8, 3584CH, Utrecht, The Netherlands
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18
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Malvino ML, Bott AJ, Green CE, Majumdar T, Hind SR. Influence of Flagellin Polymorphisms, Gene Regulation, and Responsive Memory on the Motility of Xanthomonas Species That Cause Bacterial Spot Disease of Solanaceous Plants. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2022; 35:157-169. [PMID: 34732057 DOI: 10.1094/mpmi-08-21-0211-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Increasingly, new evidence has demonstrated variability in the epitope regions of bacterial flagellin, including in regions harboring the microbe-associated molecular patterns flg22 and flgII-28 that are recognized by the pattern recognition receptors FLS2 and FLS3, respectively. Additionally, because bacterial motility is known to contribute to pathogen virulence and chemotaxis, reductions in or loss of motility can significantly reduce bacterial fitness. In this study, we determined that variations in flg22 and flgII-28 epitopes allow some but not all Xanthomonas spp. to evade both FLS2- and FLS3-mediated oxidative burst responses. We observed variation in the motility for many isolates, regardless of their flagellin sequence. Instead, we determined that past growth conditions may have a significant impact on the motility status of isolates, because we could minimize this variability by inducing motility using chemoattractant assays. Additionally, motility could be significantly suppressed under nutrient-limited conditions, and bacteria could "remember" its prior motility status after storage at ultracold temperatures. Finally, we observed larger bacterial populations of strains with flagellin variants predicted not to be recognized by either FLS2 or FLS3, suggesting that these bacteria can evade flagellin recognition in tomato plants. Although some flagellin variants may impart altered motility and differential recognition by the host immune system, external growth parameters and gene expression regulation appear to have more significant impacts on the motility phenotypes for these Xanthomonas spp.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Maria L Malvino
- Department of Crop Sciences, University of Illinois, Urbana, IL 61801, U.S.A
| | - Amie J Bott
- Department of Crop Sciences, University of Illinois, Urbana, IL 61801, U.S.A
| | - Cory E Green
- Department of Crop Sciences, University of Illinois, Urbana, IL 61801, U.S.A
| | - Tanvi Majumdar
- Department of Crop Sciences, University of Illinois, Urbana, IL 61801, U.S.A
| | - Sarah R Hind
- Department of Crop Sciences, University of Illinois, Urbana, IL 61801, U.S.A
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Yu C, Yang F, Xue D, Wang X, Chen H. The Regulatory Functions of σ 54 Factor in Phytopathogenic Bacteria. Int J Mol Sci 2021; 22:ijms222312692. [PMID: 34884502 PMCID: PMC8657755 DOI: 10.3390/ijms222312692] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/16/2021] [Accepted: 11/22/2021] [Indexed: 12/24/2022] Open
Abstract
σ54 factor (RpoN), a type of transcriptional regulatory factor, is widely found in pathogenic bacteria. It binds to core RNA polymerase (RNAP) and regulates the transcription of many functional genes in an enhancer-binding protein (EBP)-dependent manner. σ54 has two conserved functional domains: the activator-interacting domain located at the N-terminal and the DNA-binding domain located at the C-terminal. RpoN directly binds to the highly conserved sequence, GGN10GC, at the −24/−12 position relative to the transcription start site of target genes. In general, bacteria contain one or two RpoNs but multiple EBPs. A single RpoN can bind to different EBPs in order to regulate various biological functions. Thus, the overlapping and unique regulatory pathways of two RpoNs and multiple EBP-dependent regulatory pathways form a complex regulatory network in bacteria. However, the regulatory role of RpoN and EBPs is still poorly understood in phytopathogenic bacteria, which cause economically important crop diseases and pose a serious threat to world food security. In this review, we summarize the current knowledge on the regulatory function of RpoN, including swimming motility, flagella synthesis, bacterial growth, type IV pilus (T4Ps), twitching motility, type III secretion system (T3SS), and virulence-associated phenotypes in phytopathogenic bacteria. These findings and knowledge prove the key regulatory role of RpoN in bacterial growth and pathogenesis, as well as lay the groundwork for further elucidation of the complex regulatory network of RpoN in bacteria.
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Affiliation(s)
- Chao Yu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (C.Y.); (F.Y.)
| | - Fenghuan Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (C.Y.); (F.Y.)
| | - Dingrong Xue
- National Engineering Laboratory of Grain Storage and Logistics, Academy of National Food and Strategic Reserves Administration, No. 11 Baiwanzhuang Street, Xicheng District, Beijing 100037, China;
| | - Xiuna Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China;
| | - Huamin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (C.Y.); (F.Y.)
- Correspondence:
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Multiple Copies of flhDC in Paraburkholderia unamae Regulate Flagellar Gene Expression, Motility, and Biofilm Formation. J Bacteriol 2021; 203:e0029321. [PMID: 34543106 DOI: 10.1128/jb.00293-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
FlhDC is a heterohexameric complex that acts as a master regulator of flagellar biosynthesis genes in numerous bacteria. Previous studies have identified a single flhDC operon encoding this complex. However, we found that two flhDC loci are present throughout Paraburkholderia, and two additional flhC copies are also present in Paraburkholderia unamae. Systematic deletion analysis in P. unamae of the different flhDC copies showed that one of the operons, flhDC1, plays the predominant role, with deletion of its genes resulting in a severe inhibition of motility and biofilm formation. Expression analysis using promoter-lacZ fusions and real-time quantitative PCR support the primary role of flhDC1 in flagellar gene regulation, with flhDC2 a secondary contributor. Phylogenetic analysis shows the presence of the flhDC1 and flhDC2 operons throughout Paraburkholderia. In contrast, Burkholderia and other bacteria only carry the copy syntenous with flhDC2. The variations in impact each copy of flhDC has on downstream processes indicate that regulation of FlhDC in P. unamae, and likely other Paraburkholderia species, is regulated at least in part by the presence of multiple copies of these genes. IMPORTANCE Motility is important in the colonization of plant roots by beneficial and pathogenic bacteria, with flagella playing essential roles in host cell adhesion, entrance, and biofilm formation. Flagellar biosynthesis is energetically expensive. Its complex regulation by the FlhDC master regulator is well studied in peritrichous flagella expressing enterics. We report the unique presence throughout Paraburkholderia of multiple copies of flhDC. In P. unamae, the flhDC1 copy showed higher expression and a greater effect on swim motility, flagellar development, and regulation of downstream genes, than the flhDC2 copy that is syntenous to flhDC in Escherichia coli and pathogenic Burkholderia spp. The flhDC genes have evolved differently in these plant-growth-promoting bacteria, giving an additional layer of complexity in gene regulation by FlhDC.
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21
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Pochonia chlamydosporia Isolate PC-170-Induced Expression of Marker Genes for Defense Pathways in Tomatoes Challenged by Different Pathogens. Microorganisms 2021; 9:microorganisms9091882. [PMID: 34576777 PMCID: PMC8470021 DOI: 10.3390/microorganisms9091882] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/25/2021] [Accepted: 08/31/2021] [Indexed: 12/26/2022] Open
Abstract
Pochonia chlamydosporia is a fungal parasite of nematode eggs. Studies have shown that some strains of Pochonia chlamydosporia can promote plant growth and induce plants’ systemic resistance to root-knot nematodes by colonizing in their roots. This study aimed to verify the effect of the PC-170 strain on tomato growth and systemic resistance. Split-root experiments were conducted to observe the systemic resistance induced by PC-170. To explore the defense pathway that was excited due to the colonization by PC-170, we tested the expression of marker genes for defense pathways, and used mutant lines to verify the role of plant defense pathways. Our results showed that PC-170 can colonize roots, and promotes growth. We found a role for jasmonic acid (JA) in modulating tomato colonization by PC-170. PC-170 can activate tomato defense responses to reduce susceptibility to infection by the root-knot nematode Meloidogyne incognita, and induced resistance to some pathogens in tomatoes. The marker genes of the defense pathway were significantly induced after PC-170 colonization. However, salicylic acid (SA)- and jasmonic acid (JA)-dependent defenses in roots were variable with the invasion of different pathogens. Defense pathways play different roles at different points in time. SA- and JA-dependent defense pathways were shown to cross-communicate. Different phytohormones have been involved in tomato plants’ responses against different pathogens. Our study confirmed that adaptive JA signaling is necessary to regulate PC-170 colonization and induce systemic resistance in tomatoes.
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Han S, Yang L, Wang Y, Ran Y, Li S, Ding W. Preliminary Studies on the Antibacterial Mechanism of a New Plant-Derived Compound, 7-Methoxycoumarin, Against Ralstonia solanacearum. Front Microbiol 2021; 12:697911. [PMID: 34421853 PMCID: PMC8377673 DOI: 10.3389/fmicb.2021.697911] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 07/19/2021] [Indexed: 12/04/2022] Open
Abstract
Ralstonia solanacearum (R. solanacearum) is one of the most devastating plant bacterial pathogens and leads to serious economic losses in crops worldwide. In this study, the antibacterial mechanism of 7-methoxycoumarin, a new coumarin antibiotic, was preliminarily investigated by the observation of symptoms and physical and biochemical analyses. The results showed that 7-methoxycoumarin significantly suppressed bacterial growth of R. solanacearum, with the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values of 75 and 175 mg/L, respectively. Electron microscopy observations showed that the bacterial cell membrane was destroyed after 7-methoxycoumarin treatment. Biofilm formation of R. solanacearum was significantly suppressed by 7-methoxycoumarin at concentrations ranging from 25 to 100 mg/L. Furthermore, virulence-associated genes epsE, hrpG, and popA of R. solanacearum were significantly inhibited by 7-methoxycoumarin. The application of 7-methoxycoumarin effectively suppressed tobacco bacterial wilt progress in pot experiments, with relative control efficiencies of 83.61, 68.78, and 58.11% at 6, 8, and 10 days post inoculation, respectively.
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Affiliation(s)
- Songting Han
- Laboratory of Natural Products Pesticides, College of Plant Protection, Southwest University, Chongqing, China
| | - Liang Yang
- Laboratory of Natural Products Pesticides, College of Plant Protection, Southwest University, Chongqing, China
| | - Yao Wang
- Laboratory of Natural Products Pesticides, College of Plant Protection, Southwest University, Chongqing, China
| | - Yuao Ran
- Laboratory of Natural Products Pesticides, College of Plant Protection, Southwest University, Chongqing, China
| | - Shili Li
- Laboratory of Natural Products Pesticides, College of Plant Protection, Southwest University, Chongqing, China
| | - Wei Ding
- Laboratory of Natural Products Pesticides, College of Plant Protection, Southwest University, Chongqing, China
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Tano J, Ripa MB, Tondo ML, Carrau A, Petrocelli S, Rodriguez MV, Ferreira V, Siri MI, Piskulic L, Orellano EG. Light modulates important physiological features of Ralstonia pseudosolanacearum during the colonization of tomato plants. Sci Rep 2021; 11:14531. [PMID: 34267245 PMCID: PMC8282871 DOI: 10.1038/s41598-021-93871-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 06/25/2021] [Indexed: 02/06/2023] Open
Abstract
Ralstonia pseudosolanacearum GMI1000 (Rpso GMI1000) is a soil-borne vascular phytopathogen that infects host plants through the root system causing wilting disease in a wide range of agro-economic interest crops, producing economical losses. Several features contribute to the full bacterial virulence. In this work we study the participation of light, an important environmental factor, in the regulation of the physiological attributes and infectivity of Rpso GMI1000. In silico analysis of the Rpso genome revealed the presence of a Rsp0254 gene, which encodes a putative blue light LOV-type photoreceptor. We constructed a mutant strain of Rpso lacking the LOV protein and found that the loss of this protein and light, influenced characteristics involved in the pathogenicity process such as motility, adhesion and the biofilms development, which allows the successful host plant colonization, rendering bacterial wilt. This protein could be involved in the adaptive responses to environmental changes. We demonstrated that light sensing and the LOV protein, would be used as a location signal in the host plant, to regulate the expression of several virulence factors, in a time and tissue dependent way. Consequently, bacteria could use an external signal and Rpsolov gene to know their location within plant tissue during the colonization process.
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Affiliation(s)
- Josefina Tano
- Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas (IBR-FBIOyF), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Rosario (CONICET-UNR), Suipacha 531, S2002LRK, Rosario, Argentina
| | - María Belén Ripa
- Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas (IBR-FBIOyF), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Rosario (CONICET-UNR), Suipacha 531, S2002LRK, Rosario, Argentina
| | - María Laura Tondo
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Analía Carrau
- Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas (IBR-FBIOyF), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Rosario (CONICET-UNR), Suipacha 531, S2002LRK, Rosario, Argentina
| | - Silvana Petrocelli
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - María Victoria Rodriguez
- Área Biología Vegetal, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Virginia Ferreira
- Área Microbiología, Departamento de Biociencias, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - María Inés Siri
- Área Microbiología, Departamento de Biociencias, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Laura Piskulic
- Área Estadística y Procesamiento de datos, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Elena Graciela Orellano
- Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas (IBR-FBIOyF), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Rosario (CONICET-UNR), Suipacha 531, S2002LRK, Rosario, Argentina.
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de Pedro-Jové R, Puigvert M, Sebastià P, Macho AP, Monteiro JS, Coll NS, Setúbal JC, Valls M. Dynamic expression of Ralstonia solanacearum virulence factors and metabolism-controlling genes during plant infection. BMC Genomics 2021; 22:170. [PMID: 33750302 PMCID: PMC7941725 DOI: 10.1186/s12864-021-07457-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 02/19/2021] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Ralstonia solanacearum is the causal agent of bacterial wilt, a devastating plant disease responsible for serious economic losses especially on potato, tomato, and other solanaceous plant species in temperate countries. In R. solanacearum, gene expression analysis has been key to unravel many virulence determinants as well as their regulatory networks. However, most of these assays have been performed using either bacteria grown in minimal medium or in planta, after symptom onset, which occurs at late stages of colonization. Thus, little is known about the genetic program that coordinates virulence gene expression and metabolic adaptation along the different stages of plant infection by R. solanacearum. RESULTS We performed an RNA-sequencing analysis of the transcriptome of bacteria recovered from potato apoplast and from the xylem of asymptomatic or wilted potato plants, which correspond to three different conditions (Apoplast, Early and Late xylem). Our results show dynamic expression of metabolism-controlling genes and virulence factors during parasitic growth inside the plant. Flagellar motility genes were especially up-regulated in the apoplast and twitching motility genes showed a more sustained expression in planta regardless of the condition. Xylem-induced genes included virulence genes, such as the type III secretion system (T3SS) and most of its related effectors and nitrogen utilisation genes. The upstream regulators of the T3SS were exclusively up-regulated in the apoplast, preceding the induction of their downstream targets. Finally, a large subset of genes involved in central metabolism was exclusively down-regulated in the xylem at late infection stages. CONCLUSIONS This is the first report describing R. solanacearum dynamic transcriptional changes within the plant during infection. Our data define four main genetic programmes that define gene pathogen physiology during plant colonisation. The described expression of virulence genes, which might reflect bacterial states in different infection stages, provides key information on the R. solanacearum potato infection process.
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Affiliation(s)
- R de Pedro-Jové
- Department of Genetics, University of Barcelona, Barcelona, Catalonia, Spain
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - M Puigvert
- Department of Genetics, University of Barcelona, Barcelona, Catalonia, Spain
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - P Sebastià
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - A P Macho
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 201602, China
| | - J S Monteiro
- Departamento de Bioquímica, Universidade de São Paulo, São Paulo, Brazil
| | - N S Coll
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - J C Setúbal
- Departamento de Bioquímica, Universidade de São Paulo, São Paulo, Brazil
| | - M Valls
- Department of Genetics, University of Barcelona, Barcelona, Catalonia, Spain.
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain.
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Rajamma SB, Raj A, Kalampalath V, Eapen SJ. Elucidation of antibacterial effect of calcium chloride against Ralstonia pseudosolanacearum race 4 biovar 3 infecting ginger (Zingiber officinale Rosc.). Arch Microbiol 2021; 203:663-671. [PMID: 33029663 DOI: 10.1007/s00203-020-02052-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 08/25/2020] [Accepted: 09/15/2020] [Indexed: 11/25/2022]
Abstract
Bacterial wilt incited by Ralstonia pseudosolanacearum (Rps) race 4 biovar 3 is a serious threat to ginger (Zingiber officinale Rosc.) cultivation throughout the ginger growing tracts and warrants effective remedial measures since most of the strategies failed at field level implementation. After a series of experiments, calcium chloride was found to be effective against Rps both in vitro and in planta and its prophylactic effect has been successfully demonstrated under field conditions. CaCl2 at a concentration of > 2% significantly inhibited Rps under in vitro conditions. Calcium is an important nutritional element imparts a major role in plant disease resistance, and numerous studies have demonstrated the mitigating effect of calcium for disease management. CaCl2 being inhibitory to Rps, the mechanism of inhibition by CaCl2 against Rps was elucidated by a series of in vitro assays including swarming motility and biofilm formation. Direct inhibition was also studied using Scanning Electron Microscopy (SEM). The minimum bactericidal concentration and minimum inhibitory concentration were found to be around 3% while the EC 90 value was found to be 2.25%. The SEM analysis revealed the destruction of cell structure by making perforations on the cell surface. CaCl2 at the targeted concentrations inhibited biofilm formation as well as swarming motility of Rps. These findings suggest that CaCl2 exhibits strong antibacterial activity against Rps and has the potential to be used as an effective bactericide for Rps in managing bacterial wilt in ginger.
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Affiliation(s)
- Suseela Bhai Rajamma
- ICAR-Indian Institute of Spices Research, Marikunnu P O, Kozhikode, Kerala, 673012, India.
| | - Ammu Raj
- ICAR-Indian Institute of Spices Research, Marikunnu P O, Kozhikode, Kerala, 673012, India
| | - Vincy Kalampalath
- ICAR-Indian Institute of Spices Research, Marikunnu P O, Kozhikode, Kerala, 673012, India
| | - Santhosh J Eapen
- ICAR-Indian Institute of Spices Research, Marikunnu P O, Kozhikode, Kerala, 673012, India
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Tyrosine Nitration of Flagellins: a Response of Sinorhizobium meliloti to Nitrosative Stress. Appl Environ Microbiol 2020; 87:AEM.02210-20. [PMID: 33067191 DOI: 10.1128/aem.02210-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 10/13/2020] [Indexed: 12/13/2022] Open
Abstract
Rhizobia are bacteria which can either live as free organisms in the soil or interact with plants of the legume family with, as a result, the formation of root organs called nodules in which differentiated endosymbiotic bacteria fix atmospheric nitrogen to the plant's benefit. In both lifestyles, rhizobia are exposed to nitric oxide (NO) which can be perceived as a signaling or toxic molecule. NO can act at the transcriptional level but can also modify proteins by S-nitrosylation of cysteine or nitration of tyrosine residues. However, only a few molecular targets of NO have been described in bacteria and none of them have been characterized in rhizobia. Here, we examined tyrosine nitration of Sinorhizobium meliloti proteins induced by NO. We found three tyrosine-nitrated proteins in S. meliloti grown under free-living conditions, in response to an NO donor. Two nitroproteins were identified by mass spectrometry and correspond to flagellins A and B. We showed that one of the nitratable tyrosines is essential to flagellin function in motility.IMPORTANCE Rhizobia are found as free-living bacteria in the soil or in interaction with plants and are exposed to nitric oxide (NO) in both environments. NO is known to have many effects on animals, plants, and bacteria where only a few molecular targets of NO have been described so far. We identified flagellin A and B by mass spectrometry as tyrosine-nitrated proteins in Sinorhizobium meliloti in vivo We also showed that one of the nitratable tyrosines is essential to flagellin function in motility. The results enhanced our understanding of NO effects on rhizobia. Identification of bacterial flagellin nitration opens a new possible role of NO in plant-microbe interactions.
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The LysR-Type Transcriptional Regulator CrgA Negatively Regulates the Flagellar Master Regulator flhDC in Ralstonia solanacearum GMI1000. J Bacteriol 2020; 203:JB.00419-20. [PMID: 33046561 DOI: 10.1128/jb.00419-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 10/03/2020] [Indexed: 01/07/2023] Open
Abstract
The invasion and colonization of host plants by the destructive pathogen Ralstonia solanacearum rely on its cell motility, which is controlled by multiple factors. Here, we report that the LysR-type transcriptional regulator CrgA (RS_RS16695) represses cell motility in R. solanacearum GMI1000. CrgA possesses common features of a LysR-type transcriptional regulator and contains an N-terminal helix-turn-helix motif as well as a C-terminal LysR substrate-binding domain. Deletion of crgA results in an enhanced swim ring and increased transcription of flhDC In addition, the ΔcrgA mutant possesses more polar flagella than wild-type GMI1000 and exhibits higher expression of the flagellin gene fliC Despite these alterations, the ΔcrgA mutant did not have a detectable growth defect in culture. Yeast one-hybrid and electrophoretic mobility shift assays revealed that CrgA interacts directly with the flhDC promoter. Expressing the β-glucuronidase (GUS) reporter under the control of the crgA promoter showed that crgA transcription is dependent on cell density. Soil-soaking inoculation with the crgA mutant caused wilt symptoms on tomato (Solanum lycopersicum L. cv. Hong yangli) plants earlier than inoculation with the wild-type GMI1000 but resulted in lower disease severity. We conclude that the R. solanacearum regulator CrgA represses flhDC expression and consequently affects the expression of fliC to modulate cell motility, thereby conditioning disease development in host plants.IMPORTANCE Ralstonia solanacearum is a widely distributed soilborne plant pathogen that causes bacterial wilt disease on diverse plant species. Motility is a critical virulence attribute of R. solanacearum because it allows this pathogen to efficiently invade and colonize host plants. In R. solanacearum, motility-defective strains are markedly affected in pathogenicity, which is coregulated with multiple virulence factors. In this study, we identified a new LysR-type transcriptional regulator (LTTR), CrgA, that negatively regulates motility. The mutation of the corresponding gene leads to the precocious appearance of wilt symptoms on tomato plants when the pathogen is introduced using soil-soaking inoculation. This study indicates that the regulation of R. solanacearum motility is more complex than previously thought and enhances our understanding of flagellum regulation in R. solanacearum.
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Endophytes from Gnetum gnemon L. can protect seedlings against the infection of phytopathogenic bacterium Ralstonia solanacearum as well as promote plant growth in tomato. Microbiol Res 2020; 238:126503. [DOI: 10.1016/j.micres.2020.126503] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 04/19/2020] [Accepted: 04/25/2020] [Indexed: 02/01/2023]
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The involvement of the Type Six Secretion System (T6SS) in the virulence of Ralstonia solanacearum on brinjal. 3 Biotech 2020; 10:324. [PMID: 32656057 DOI: 10.1007/s13205-020-02311-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/19/2020] [Indexed: 10/24/2022] Open
Abstract
Ralstonia solanacearum is an important soil-borne plant pathogen which causes bacterial wilt in a large number of crops. Bacterial Type Six Secretion System (T6SS) is known to participate in pathogenesis, bacterial interaction and inter-bacterial competition. Contribution of T6SS in the virulence of R. solanacearum on eggplant (Solanum melongena L) is studied. In this study, five T6SS gene (ompA, vgrG3, hcp, tssH and tssM) mutants have been developed by insertional mutagenesis and the virulence of the mutants was evaluated on eggplant. In general, the T6SS mutants showed significant reduction of wilt on eggplant. R. solanacearum mutant of ompA gene significantly reduced the wilt from day five through day eight in petiole inoculation. In soil drench inoculation, R. solanacearum mutant of vgrG3 gene reduced the wilt on eggplant and was significantly different throughout the experimental period. Other mutants, viz., tssH, tssM and hcp, also reduced the wilt during the initial stages of disease development. This is the first report on the role of T6SS genes, ompA, vgrG3, hcp and tssH on virulence of R. solanacearum.
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Zhang Y, Han L, Zhang L, Xu C, Shi X, Hikichi Y, Ohnishi K. Expression of Ralstonia solanacearum type III secretion system is dependent on a novel type 4 pili (T4P) assembly protein (TapV) but is T4P independent. MOLECULAR PLANT PATHOLOGY 2020; 21:777-793. [PMID: 32196936 PMCID: PMC7214476 DOI: 10.1111/mpp.12930] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/08/2020] [Accepted: 02/14/2020] [Indexed: 06/10/2023]
Abstract
Type IV pili (T4P) are virulence factors in various pathogenic bacteria of animals and plants that play important roles in twitching motility, swimming motility, biofilm formation, and adhesion to host cells. Here, we genetically characterized functional roles of a putative T4P assembly protein TapV (Rsc1986 in reference strain GMI1000) and its homologue Rsp0189, which shares 58% amino acid identity with TapV, in Ralstonia solanacearum. Deletion of tapV, but not rsp0189, resulted in significantly impaired twitching motility, swimming motility, and adhesion to tomato roots, which are consistent as phenotypes of the pilA mutant (a known R. solanacearum T4P-deficient mutant). However, unlike the pilA mutant, the tapV mutant produced more biofilm than the wild-type strain. Our gene expression studies revealed that TapV, but not Rsp0189, is important for expression of a type III secretion system (T3SS, a pathogenicity determinant of R. solanacearum) both in vitro and in planta, but it is T4P independent. We further revealed that TapV affected the T3SS expression via the PhcA-TapV-PrhG-HrpB pathway, consistent with previous reports that PhcA positively regulates expression of pilA and prhG. Moreover, deletion of tapV, but not rsp0189, significantly impaired the ability to migrate into and colonize xylem vessels of host plants, but there was no alteration in intercellular proliferation of R. solanacearum in tobacco leaves, which is similar to the pilA mutant. The tapV mutant showed significantly impaired virulence in host plants. This is the first report on the impact of T4P components on the T3SS, providing novel insights into our understanding of various biological functions of T4P and the complex regulatory pathway of T3SS in R. solanacearum.
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Affiliation(s)
- Yong Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Key Laboratory of Efficient Utilization of Soil and Fertilizer ResourcesChongqingChina
| | - Liangliang Han
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Research Institute of Molecular GeneticsKochi UniversityKochiJapan
| | - Lichun Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Research Institute of Molecular GeneticsKochi UniversityKochiJapan
| | - Changzheng Xu
- College of Life scienceSouthwest UniversityChongqingChina
| | - Xiaojun Shi
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Key Laboratory of Efficient Utilization of Soil and Fertilizer ResourcesChongqingChina
| | - Yasufumi Hikichi
- Laboratory of Plant Pathology and BiotechnologyKochi UniversityKochiJapan
| | - Kouhei Ohnishi
- Research Institute of Molecular GeneticsKochi UniversityKochiJapan
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Regulators of nitric oxide signaling triggered by host perception in a plant pathogen. Proc Natl Acad Sci U S A 2020; 117:11147-11157. [PMID: 32376629 DOI: 10.1073/pnas.1918977117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The rhizosphere interaction between plant roots or pathogenic microbes is initiated by mutual exchange of signals. However, how soil pathogens sense host signals is largely unknown. Here, we studied early molecular events associated with host recognition in Fusarium graminearum, an economically important fungal pathogen that can infect both roots and heads of cereal crops. We found that host sensing prior to physical contact with plant roots radically alters the transcriptome and triggers nitric oxide (NO) production in F. graminearum We identified an ankyrin-repeat domain containing protein (FgANK1) required for host-mediated NO production and virulence in F. graminearum In the absence of host plant, FgANK1 resides in the cytoplasm. In response to host signals, FgANK1 translocates to the nucleus and interacts with a zinc finger transcription factor (FgZC1), also required for specific binding to the nitrate reductase (NR) promoter, NO production, and virulence in F. graminearum Our results reveal mechanistic insights into host-recognition strategies employed by soil pathogens.
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Zhang L, Chen W, Jiang Q, Fei Z, Xiao M. Genome analysis of plant growth-promoting rhizobacterium Pseudomonas chlororaphis subsp. aurantiaca JD37 and insights from comparasion of genomics with three Pseudomonas strains. Microbiol Res 2020; 237:126483. [PMID: 32402945 DOI: 10.1016/j.micres.2020.126483] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 04/14/2020] [Accepted: 04/16/2020] [Indexed: 11/19/2022]
Abstract
Pseudomonas chlororaphis subsp. aurantiaca strain JD37 is a plant growth-promoting rhizobacterium (PGPR), which has important biotechnological features such as plant growth promotion, rhizosphere colonization and biocontrol activities. In present study, the genome sequence of JD37 was obtained and comparative genomic analysis were performed to explore unique features of the JD37 genome and its relationship with other Pseudomonas PGPR: P. chlororaphis PA23, P. protegens Pf-5 and P. aeruginosa M18. JD37 possessed a single circular chromosome of 6,702,062 bp in length with an average GC content of 62.75 %. No plasmid was detected in JD37. A total of 5003 functional proteins of JD37 were predicted according to the clusters of orthologous groups (COGs) database. The JD37 genome consisted of various genes involved in plant growth promotion, biocontrol activities and defense responses. Genes involved in the rhizosphere colonization and motility were also found in the genome of JD37, suggesting the common plant growth-promoting traits in PGPR. The identified resistance genes (e.g. those related to metal resistance, antibiotics, and osmotic and temperature-shock) and secondary metabolite biosynthesis revealed the pathways for metabolites it produced. Data presented in present study further provided valuable information on its molecular genetics and adaptive capacity in the rhizosphere niche.
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Affiliation(s)
- Lei Zhang
- Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Wenbo Chen
- Boyce Thompson Institute, Cornell University, Ithaca, NY, 14853, USA
| | - Qiuyue Jiang
- Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China; Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Zhangjun Fei
- Boyce Thompson Institute, Cornell University, Ithaca, NY, 14853, USA
| | - Ming Xiao
- Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China.
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Liu Y, Tan X, Cheng H, Gong J, Zhang Y, Wang D, Ding W. The cold shock family gene cspD3 is involved in the pathogenicity of Ralstonia solanacearum CQPS-1 to tobacco. Microb Pathog 2020; 142:104091. [PMID: 32088390 DOI: 10.1016/j.micpath.2020.104091] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 02/19/2020] [Accepted: 02/19/2020] [Indexed: 10/25/2022]
Abstract
Cold shock proteins (Csps) are small and highly conserved proteins that have target RNA- and DNA-binding activities. Csps play roles in different cellular processes and show functional redundancy. Ralstonia solanacearum, the agent of bacterial wilt, has 4 or 5 Csps based on genome analysis. However, the functions of all Csps in R. solanacearum remain unclear. According to phylogenetic analysis, the Csps from R. solanacearum are clustered into a group with CspD from E. coli. Here, we studied the role of CspD3, which was closer to CspD of E. coli in the phylogenetic tree. A cspD3 deletion strain was constructed to assess its effect on the phenotype of R. solanacearum, including growth, biofilm formation, motility, and virulence. The results showed that cspD3 of R. solanacearum was not necessary for normal growth, cold-shock adaptation, or biofilm formation. However, deletion of cspD3 in R. solanacearum CQPS-1 led to increased swimming motility, and the mean diameters of swimming haloes produced by the ΔcspD3 mutant were 1.3-fold larger than those produced by wild-type strain and 1.2-fold larger than those produced by the complemented strain. More importantly, the virulence of the cspD3 deletion mutant on susceptible tobacco plants was significantly attenuated compared to the wild-type strain. At 20 days after inoculation, the disease index of the ΔcspD3 mutant was 2.27, which was reduced by 1.6-fold relative to the wild-type strain. To assess the molecular response influenced by cspD3, the expressions of the main motility-associated genes and virulence-associated genes including flgM, fliA, pehS, pehR, hrpG, xpsR, and prhI in R. solanacearum were measured. The results showed that the expressions of hrpG, xpsR, and prhI were significantly decreased in cspD3 deletion mutant. Collectively, our findings showed that Csps are involved in the regulation of motility and virulence in R. solanacearum.
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Affiliation(s)
- Ying Liu
- College of Plant Protection, Southwest University, Chongqing, China
| | - Xi Tan
- College of Plant Protection, Southwest University, Chongqing, China
| | - Haojin Cheng
- College of Plant Protection, Southwest University, Chongqing, China
| | - Jie Gong
- College of Plant Protection, Southwest University, Chongqing, China
| | - Yong Zhang
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Daibin Wang
- Chongqing Tobacco Science Research Institute, Chongqing, China.
| | - Wei Ding
- College of Plant Protection, Southwest University, Chongqing, China.
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Park H, Do E, Kim M, Park HJ, Lee J, Han SW. A LysR-Type Transcriptional Regulator LcrX Is Involved in Virulence, Biofilm Formation, Swimming Motility, Siderophore Secretion, and Growth in Sugar Sources in Xanthomonas axonopodis Pv. glycines. FRONTIERS IN PLANT SCIENCE 2020; 10:1657. [PMID: 31998344 PMCID: PMC6965072 DOI: 10.3389/fpls.2019.01657] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 11/25/2019] [Indexed: 05/30/2023]
Abstract
Xanthomonas axonopodis pv. glycines (Xag) is a Gram-negative bacterium that causes bacterial pustule disease in soybean. To acclimate to new environments, the expression of genes in bacteria is controlled directly or indirectly by diverse transcriptional factors. Among them, LysR type transcriptional regulators are well-characterized and abundant in bacteria. In a previous study, comparative proteomic analysis revealed that LysR type carbohydrate-related transcriptional regulator in Xag (LcrX) was more abundant in XVM2, which is a minimal medium, compared with a rich medium. However, the functions of LcrX in Xag have not been characterized. In this study, we generated an LcrX-overexpressing strain, Xag(LcrX), and the knockout mutant strain, XagΔlcrX(EV), to elucidate the functions of LcrX. Bacterial multiplication of Xag(LcrX) in soybean was significantly impaired, indicating that LcrX is related to virulence. Comparative proteomic analysis revealed that LcrX is mainly involved in carbohydrate metabolism/transport and inorganic ion transport/metabolism. Based on the results of proteomics analysis, diverse phenotypic assays were carried out. A gel electrophoresis mobility shift assay demonstrated that LcrX specifically bound to the putative promoter regions of genes encoding putative fructose 1,6-bisphosphatase and protease. Through a 96-well plate assay under various conditions, we confirmed that the growth of Xag(LcrX) was dramatically affected in the presence of various carbon sources, while the growth of XagΔlcrX(EV) was only slightly changed. Biofilm formation activity was reduced in Xag(LcrX) but enhanced in XagΔlcrX(EV). The production of siderophores was also decreased in Xag(LcrX) but not altered in XagΔlcrX(EV). In contrast, LcrX was not associated with exopolysaccharide production, protease activity, or bacterial motility. These findings provide new insights into the functions of a carbohydrate-related transcriptional regulator in Xag.
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Affiliation(s)
- Hanbi Park
- Department of Plant Science and Technology, Chung-Ang University, Anseong, South Korea
| | - Eunsoo Do
- Department of Systems Biotechnology, Chung-Ang University, Anseong, South Korea
| | - Minyoung Kim
- Department of Plant Science and Technology, Chung-Ang University, Anseong, South Korea
| | - Hye-Jee Park
- Department of Plant Science and Technology, Chung-Ang University, Anseong, South Korea
| | - Jongchan Lee
- Department of Plant Science and Technology, Chung-Ang University, Anseong, South Korea
| | - Sang-Wook Han
- Department of Plant Science and Technology, Chung-Ang University, Anseong, South Korea
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Zhang Y, Zhang W, Han L, Li J, Shi X, Hikichi Y, Ohnishi K. Involvement of a PadR regulator PrhP on virulence of Ralstonia solanacearum by controlling detoxification of phenolic acids and type III secretion system. MOLECULAR PLANT PATHOLOGY 2019; 20:1477-1490. [PMID: 31392803 PMCID: PMC6804342 DOI: 10.1111/mpp.12854] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Ralstonia solanacearum can metabolize ferulic acid (FA) and salicylic acid (SA), two representative phenolic acids, to protect it from toxicity of phenolic acids. Here, we genetically demonstrated a novel phenolic acid decarboxylase regulator (PadR)-like regulator PrhP as a positive regulator on detoxification of SA and FA in R. solanacearum. Although the ability to degrade SA and FA enhances the infection process of R. solanacearum toward host plants, PrhP greatly contributes to the infection process besides degradation of SA and FA. Our results from the growth assay, promoter activity assay, RNA-seq and qRT-PCR revealed that PrhP plays multiple roles in the virulence of R. solanacearum: (1) positively regulates expression of genes for degradation of SA and FA; (2) positively regulates expression of genes encoding type III secretion system (T3SS) and type III effectors both in vitro and in planta; (3) positively regulates expression of many virulence-related genes, such as the flagella, type IV pili and cell wall degradation enzymes; and (4) is important for the extensive proliferation in planta. The T3SS is one of the essential pathogenicity determinants in many pathogenic bacteria, and PrhP positively regulates its expression mediated with the key regulator HrpB but through some novel pathway to HrpB in R. solanacearum. This is the first report on PadR regulators to regulate the T3SS and it could improve our understanding of the various biological functions of PadR regulators and the complex regulatory pathway on T3SS in R. solanacearum.
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Affiliation(s)
- Yong Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Key Laboratory of Efficient Utilization of Soil and Fertilizer ResourcesChongqing
| | - Weiqi Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
| | - Liangliang Han
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Research Institute of Molecular Genetics, Kochi UniversityKochiJapan
| | - Jing Li
- The Ninth Peoples Hospital of ChongqingChongqingChina
| | - Xiaojun Shi
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Key Laboratory of Efficient Utilization of Soil and Fertilizer ResourcesChongqing
| | - Yasufumi Hikichi
- Laboratory of Plant Pathology and BiotechnologyKochi UniversityKochiJapan
| | - Kouhei Ohnishi
- Research Institute of Molecular Genetics, Kochi UniversityKochiJapan
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Guo W, Gao J, Chen Q, Ma B, Fang Y, Liu X, Chen G, Liu JZ. Crp-Like Protein Plays Both Positive and Negative Roles in Regulating the Pathogenicity of Bacterial Pustule Pathogen Xanthomonas axonopodis pv. glycines. PHYTOPATHOLOGY 2019; 109:1171-1183. [PMID: 30730787 DOI: 10.1094/phyto-07-18-0225-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The global regulator Crp-like protein (Clp) is positively involved in the production of virulence factors in some of the Xanthomonas spp. However, the functional importance of Clp in X. axonopodis pv. glycines has not been investigated previously. Here, we showed that deletion of clp led to significant reduction in the virulence of X. axonopodis pv. glycines in soybean, which was highly correlated with the drastic reductions in carbohydrates utilization, extracellular polysaccharide (EPS) production, biofilm formation, cell motility, and synthesis of cell wall degrading enzymes (CWDEs). These significantly impaired properties in the clp mutant were completely rescued by a single-copy integration of the wild-type clp into the mutant chromosome via homologous recombination. Interestingly, overexpression of clp in the wild-type strain resulted in significant increases in cell motility and synthesis of the CWDEs. To our surprise, significant reductions in carbohydrates utilization, EPS production, biofilm formation, and the protease activity were observed in the wild-type strain overexpressing clp, suggesting that Clp also plays a negative role in these properties. Furthermore, quantitative reverse transcription polymerase chain reaction analysis suggested that clp was positively regulated by the diffusible signal factor-mediated quorum-sensing system and the HrpG/HrpX cascade. Taken together, our results reveal that Clp functions as both activator and repressor in multiple biological processes in X. axonopodis pv. glycines that are essential for its full virulence.
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Affiliation(s)
- Wei Guo
- 1 Institute of Plant Genetics and Developmental Biology, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Jie Gao
- 1 Institute of Plant Genetics and Developmental Biology, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Qingshan Chen
- 2 College of Agriculture, Northeast Agricultural University, Harbin 150030, China; and
| | - Bojun Ma
- 1 Institute of Plant Genetics and Developmental Biology, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Yuan Fang
- 1 Institute of Plant Genetics and Developmental Biology, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Xia Liu
- 1 Institute of Plant Genetics and Developmental Biology, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Gongyou Chen
- 3 College of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jian-Zhong Liu
- 1 Institute of Plant Genetics and Developmental Biology, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China
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Hu X, Zhao Z, Zhuo T, Fan X, Zou H. The RSc0454-Encoded FAD-Linked Oxidase Is Indispensable for Pathogenicity in Ralstonia solanacearum GMI1000. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:697-707. [PMID: 30540527 DOI: 10.1094/mpmi-08-18-0224-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Ralstonia solanacearum is the causal agent of bacterial wilt disease. Here, we report that a large FAD-linked oxidase encoded by RSc0454 in GMI1000 is required for pathogenicity. The FAD-linked oxidase encoded by RSc0454 is composed of 1,345 amino acids, including DUF3683, lactate dehydrogenase (LDH), and succinate dehydrogenase (SDH) domains. The RSc0454 protein showed both LDH and SDH activities. To investigate its role in pathogenicity, a deletion mutant of the RSc0454 gene was constructed in GMI1000, which was impaired in its ability to cause bacterial wilt disease in tomato. A single DUF3683, LDH, or SDH domain was insufficient to restore bacterial pathogenicity. Mutagenesis of the RSc0454 gene did not affect growth rate but caused cell aggregation at the bottom of the liquid nutrient medium, which was reversed by exogenous applications of lactate, fumarate, pyruvate, and succinate. qRT-PCR and promoter LacZ fusion experiments demonstrated that RSc0454 gene transcription was induced by lactate and fumarate (both substrates of LDH). Compared with the downregulation of the succinate dehydrogenase gene sdhBADC and the lactate dehydrogenase gene ldh, RSc0454 gene transcription was enhanced in planta. This suggests that the oxidase encoded by RSc0454 was involved in a redox balance, which is in line with the different living conditions of R. solanacearum.
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Affiliation(s)
- Xun Hu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Zhiwen Zhao
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Tao Zhuo
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Xiaojing Fan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Huasong Zou
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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Royet K, Parisot N, Rodrigue A, Gueguen E, Condemine G. Identification by Tn-seq of Dickeya dadantii genes required for survival in chicory plants. MOLECULAR PLANT PATHOLOGY 2019; 20:287-306. [PMID: 30267562 PMCID: PMC6637903 DOI: 10.1111/mpp.12754] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The identification of the virulence factors of plant-pathogenic bacteria has relied on the testing of individual mutants on plants, a time-consuming process. Transposon sequencing (Tn-seq) is a very powerful method for the identification of the genes required for bacterial growth in their host. We used this method in a soft-rot pathogenic bacterium to identify the genes required for the multiplication of Dickeya dadantii in chicory. About 100 genes were identified showing decreased or increased fitness in the plant. Most had no previously attributed role in plant-bacterium interactions. Following our screening, in planta competition assays confirmed that the uridine monophosphate biosynthesis pathway and the purine biosynthesis pathway were essential to the survival of D. dadantii in the plant, as the mutants ∆carA, ∆purF, ∆purL, ∆guaB and ∆pyrE were unable to survive in the plant in contrast with the wild-type (WT) bacterium. This study also demonstrated that the biosynthetic pathways of leucine, cysteine and lysine were essential for bacterial survival in the plant and that RsmC and GcpA were important in the regulation of the infection process, as the mutants ∆rsmC and ∆gcpA were hypervirulent. Finally, our study showed that D. dadantii flagellin was glycosylated and that this modification conferred fitness to the bacterium during plant infection. Assay by this method of the large collections of environmental pathogenic strains now available will allow an easy and rapid identification of new virulence factors.
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Affiliation(s)
- Kévin Royet
- University of LyonUniversité Lyon 1, INSA de Lyon, CNRS UMR 5240 Microbiologie Adaptation et PathogénieF‐69622VilleurbanneFrance
| | - Nicolas Parisot
- University of LyonINSA‐Lyon, INRA, BF2I, UMR0203F‐69621VilleurbanneFrance
| | - Agnès Rodrigue
- University of LyonUniversité Lyon 1, INSA de Lyon, CNRS UMR 5240 Microbiologie Adaptation et PathogénieF‐69622VilleurbanneFrance
| | - Erwan Gueguen
- University of LyonUniversité Lyon 1, INSA de Lyon, CNRS UMR 5240 Microbiologie Adaptation et PathogénieF‐69622VilleurbanneFrance
| | - Guy Condemine
- University of LyonUniversité Lyon 1, INSA de Lyon, CNRS UMR 5240 Microbiologie Adaptation et PathogénieF‐69622VilleurbanneFrance
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Chen J, Mao S, Xu Z, Ding W. Various antibacterial mechanisms of biosynthesized copper oxide nanoparticles against soilborne Ralstonia solanacearum. RSC Adv 2019; 9:3788-3799. [PMID: 35518060 PMCID: PMC9060243 DOI: 10.1039/c8ra09186b] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 12/18/2018] [Indexed: 12/19/2022] Open
Abstract
The substantial antimicrobial efficacy of nanoparticles against phytopathogens has been extensively investigated for advanced agricultural applications. However, few reports have focused on soilborne pathogenic bacteria. The aim of this study was to obtain sustainably synthesized copper oxide nanoparticles (CuONPs) using papaya leaf extracts and investigate the bactericidal activity of these CuONPs against Ralstonia solanacearum, the cause of bacterial wilt, under laboratory and greenhouse conditions. The results showed that CuONPs possessed strong antibacterial activity and that all R. solanacearum were killed after exposure to 250 μg mL-1 CuONPs. CuONPs could interact with bacterial cells to prevent biofilm formation, reduce swarming motility and disturb ATP production. Ultrastructural observations by transmission electron microscopy (TEM) revealed that after interactions with CuONPs, bacterial cells suffered significantly from nanomechanical damage to the cytomembrane, accompanied by the absorption of multiple nanoparticles. In addition, molecular studies identified the downregulation mechanism of a series of genes involving pathogenesis and motility. The control efficiency of CuONPs in tobacco bacterial wilt disease management under greenhouse conditions was verified by root irrigation application, demonstrating that as-prepared CuONPs significantly reduced the disease occurrence and disease index. Our studies focused on developing biosynthesized nanoparticles as a biocompatible alternative for soilborne disease management.
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Affiliation(s)
- Juanni Chen
- Laboratory of Natural Product Pesticides, College of Plant Protection, Southwest University Chongqing 400715 China +86-23-6825-0953 +86-23-6825-0953
| | - Shuyu Mao
- Laboratory of Natural Product Pesticides, College of Plant Protection, Southwest University Chongqing 400715 China +86-23-6825-0953 +86-23-6825-0953
| | - Zhifeng Xu
- Laboratory of Natural Product Pesticides, College of Plant Protection, Southwest University Chongqing 400715 China +86-23-6825-0953 +86-23-6825-0953
| | - Wei Ding
- Laboratory of Natural Product Pesticides, College of Plant Protection, Southwest University Chongqing 400715 China +86-23-6825-0953 +86-23-6825-0953
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Tancos MA, Lowe‐Power TM, Peritore‐Galve FC, Tran TM, Allen C, Smart CD. Plant-like bacterial expansins play contrasting roles in two tomato vascular pathogens. MOLECULAR PLANT PATHOLOGY 2018; 19:1210-1221. [PMID: 28868644 PMCID: PMC5835177 DOI: 10.1111/mpp.12611] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 08/04/2017] [Accepted: 08/31/2017] [Indexed: 05/27/2023]
Abstract
Expansin proteins, which loosen plant cell walls, play critical roles in normal plant growth and development. The horizontal acquisition of functional plant-like expansin genes in numerous xylem-colonizing phytopathogenic bacteria suggests that bacterial expansins may also contribute to virulence. To investigate the role of bacterial expansins in plant diseases, we mutated the non-chimeric expansin genes (CmEXLX2 and RsEXLX) of two xylem-inhabiting bacterial pathogens, the Actinobacterium Clavibacter michiganensis ssp. michiganensis (Cmm) and the β-proteobacterium Ralstonia solanacearum (Rs), respectively. The Cmm ΔCmEXLX2 mutant caused increased symptom development on tomato, which was characterized by more rapid wilting, greater vascular necrosis and abundant atypical lesions on distant petioles. This increased disease severity correlated with larger in planta populations of the ΔCmEXLX2 mutant, even though the strains grew as well as the wild-type in vitro. Similarly, when inoculated onto tomato fruit, ΔCmEXLX2 caused significantly larger lesions with larger necrotic centres. In contrast, the Rs ΔRsEXLX mutant showed reduced virulence on tomato following root inoculation, but not following direct petiole inoculation, suggesting that the RsEXLX expansin contributes to early virulence at the root infection stage. Consistent with this finding, ΔRsEXLX attached to tomato seedling roots better than the wild-type Rs, which may prevent mutants from invading the plant's vasculature. These contrasting results demonstrate the diverse roles of non-chimeric bacterial expansins and highlight their importance in plant-bacterial interactions.
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Affiliation(s)
- Matthew A. Tancos
- Plant Pathology and Plant‐Microbe Biology Section, School of Integrative Plant SciencesCornell UniversityGenevaNY 14456USA
- Present address:
Foreign Disease‐Weed Science Research Unit, USDA‐ARSFort DetrickMD 21702USA
| | | | - F. Christopher Peritore‐Galve
- Plant Pathology and Plant‐Microbe Biology Section, School of Integrative Plant SciencesCornell UniversityGenevaNY 14456USA
| | - Tuan M. Tran
- Department of Plant PathologyUniversity of Wisconsin‐MadisonMadisonWI 53706USA
- Present address:
School of Biological SciencesNanyang Technological University639798Singapore
| | - Caitilyn Allen
- Department of Plant PathologyUniversity of Wisconsin‐MadisonMadisonWI 53706USA
| | - Christine D. Smart
- Plant Pathology and Plant‐Microbe Biology Section, School of Integrative Plant SciencesCornell UniversityGenevaNY 14456USA
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Singh N, Phukan T, Sharma PL, Kabyashree K, Barman A, Kumar R, Sonti RV, Genin S, Ray SK. An Innovative Root Inoculation Method to Study Ralstonia solanacearum Pathogenicity in Tomato Seedlings. PHYTOPATHOLOGY 2018; 108:436-442. [PMID: 29182472 DOI: 10.1094/phyto-08-17-0291-r] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this study, we report Ralstonia solanacearum pathogenicity in the early stages of tomato seedlings by an innovative root inoculation method. Pathogenicity assays were performed under gnotobiotic conditions in microfuge tubes by employing only 6- to 7-day-old tomato seedlings for root inoculation. Tomato seedlings inoculated by this method exhibited the wilted symptom within 48 h and the virulence assay can be completed in 2 weeks. Colonization of the wilted seedlings by R. solanacearum was confirmed by using gus staining as well as fluorescence microscopy. Using this method, mutants in different virulence genes such as hrpB, phcA, and pilT could be clearly distinguished from wild-type R. solanacearum. The method described here is economic in terms of space, labor, and cost as well as the required quantity of bacterial inoculum. Thus, the newly developed assay is an easy and useful approach for investigating virulence functions of the pathogen at the seedling stage of hosts, and infection under these conditions appears to require pathogenicity mechanisms used by the pathogen for infection of adult plants.
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Affiliation(s)
- N Singh
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
| | - T Phukan
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
| | - P L Sharma
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
| | - K Kabyashree
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
| | - A Barman
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
| | - R Kumar
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
| | - R V Sonti
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
| | - S Genin
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
| | - S K Ray
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
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Comparative transcriptomic studies identify specific expression patterns of virulence factors under the control of the master regulator PhcA in the Ralstonia solanacearum species complex. Microb Pathog 2018; 116:273-278. [DOI: 10.1016/j.micpath.2018.01.028] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 01/18/2018] [Accepted: 01/19/2018] [Indexed: 11/20/2022]
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Complete genome sequence of the sesame pathogen Ralstonia solanacearum strain SEPPX 05. Genes Genomics 2018; 40:657-668. [PMID: 29892946 DOI: 10.1007/s13258-018-0667-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/04/2018] [Indexed: 10/18/2022]
Abstract
Ralstonia solanacearum is a soil-borne phytopathogen associated with bacterial wilt disease of sesame. R. solanacearum is the predominant agent causing damping-off from tropical to temperate regions. Because bacterial wilt has decreased the sesame industry yield, we sequenced the SEPPX05 genome using PacBio and Illumina HiSeq 2500 systems and revealed that R. solanacearum strain SEPPX05 carries a bipartite genome consisting of a 3,930,849 bp chromosome and a 2,066,085 bp megaplasmid with 66.84% G+C content that harbors 5,427 coding sequences. Based on the whole genome, phylogenetic analysis showed that strain SEPPX05 is grouped with two phylotype I strains (EP1 and GMI1000). Pan-genomic analysis shows that R. solanacearum is a complex species with high biological diversity and was able to colonize various environments during evolution. Despite deletions, insertions, and inversions, most genes of strain SEPPX05 have relatively high levels of synteny compared with strain GMI1000. We identified 104 genes involved in virulence-related factors in the SEPPX05 genome and eight absent genes encoding T3Es of GMI1000. Comparing SEPPX05 with other species, we found highly conserved secretion systems central to modulating interactions of host bacteria. These data may provide important clues for understanding underlying pathogenic mechanisms of R. solanacearum and help in the control of sesame bacterial wilt.
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Lowe-Power TM, Hendrich CG, von Roepenack-Lahaye E, Li B, Wu D, Mitra R, Dalsing BL, Ricca P, Naidoo J, Cook D, Jancewicz A, Masson P, Thomma B, Lahaye T, Michael AJ, Allen C. Metabolomics of tomato xylem sap during bacterial wilt reveals Ralstonia solanacearum produces abundant putrescine, a metabolite that accelerates wilt disease. Environ Microbiol 2017; 20:1330-1349. [PMID: 29215193 DOI: 10.1111/1462-2920.14020] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 11/29/2017] [Accepted: 12/03/2017] [Indexed: 12/20/2022]
Abstract
Ralstonia solanacearum thrives in plant xylem vessels and causes bacterial wilt disease despite the low nutrient content of xylem sap. We found that R. solanacearum manipulates its host to increase nutrients in tomato xylem sap, enabling it to grow better in sap from infected plants than in sap from healthy plants. Untargeted GC/MS metabolomics identified 22 metabolites enriched in R. solanacearum-infected sap. Eight of these could serve as sole carbon or nitrogen sources for R. solanacearum. Putrescine, a polyamine that is not a sole carbon or nitrogen source for R. solanacearum, was enriched 76-fold to 37 µM in R. solanacearum-infected sap. R. solanacearum synthesized putrescine via a SpeC ornithine decarboxylase. A ΔspeC mutant required ≥ 15 µM exogenous putrescine to grow and could not grow alone in xylem even when plants were treated with putrescine. However, co-inoculation with wildtype rescued ΔspeC growth, indicating R. solanacearum produced and exported putrescine to xylem sap. Intriguingly, treating plants with putrescine before inoculation accelerated wilt symptom development and R. solanacearum growth and systemic spread. Xylem putrescine concentration was unchanged in putrescine-treated plants, so the exogenous putrescine likely accelerated disease indirectly by affecting host physiology. These results indicate that putrescine is a pathogen-produced virulence metabolite.
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Affiliation(s)
- Tiffany M Lowe-Power
- Department of Plant Pathology, University of Wisconsin - Madison, Madison, WI 53706, USA
| | - Connor G Hendrich
- Department of Plant Pathology, University of Wisconsin - Madison, Madison, WI 53706, USA
| | - Edda von Roepenack-Lahaye
- Leibniz Institute of Plant Biochemistry, Zentrum für Molekularbiologie der Pflanzen (ZMBP), Universität Tübingen, Tübingen, Germany
| | - Bin Li
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Dousheng Wu
- Leibniz Institute of Plant Biochemistry, Zentrum für Molekularbiologie der Pflanzen (ZMBP), Universität Tübingen, Tübingen, Germany
| | - Raka Mitra
- Department of Biology, Carleton College, Northfield, MN 55057, USA
| | - Beth L Dalsing
- Department of Plant Pathology, University of Wisconsin - Madison, Madison, WI 53706, USA
| | - Patrizia Ricca
- Leibniz Institute of Plant Biochemistry, Zentrum für Molekularbiologie der Pflanzen (ZMBP), Universität Tübingen, Tübingen, Germany
| | - Jacinth Naidoo
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - David Cook
- Laboratory of Phytopathology, Wageningen University, Wageningen, The Netherlands
| | - Amy Jancewicz
- Department of Genetics, University of Wisconsin, Madison, Madison, WI 53706, USA
| | - Patrick Masson
- Department of Genetics, University of Wisconsin, Madison, Madison, WI 53706, USA
| | - Bart Thomma
- Laboratory of Phytopathology, Wageningen University, Wageningen, The Netherlands
| | - Thomas Lahaye
- Leibniz Institute of Plant Biochemistry, Zentrum für Molekularbiologie der Pflanzen (ZMBP), Universität Tübingen, Tübingen, Germany
| | - Anthony J Michael
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin - Madison, Madison, WI 53706, USA
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Capela D, Marchetti M, Clérissi C, Perrier A, Guetta D, Gris C, Valls M, Jauneau A, Cruveiller S, Rocha EPC, Masson-Boivin C. Recruitment of a Lineage-Specific Virulence Regulatory Pathway Promotes Intracellular Infection by a Plant Pathogen Experimentally Evolved into a Legume Symbiont. Mol Biol Evol 2017; 34:2503-2521. [PMID: 28535261 DOI: 10.1093/molbev/msx165] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ecological transitions between different lifestyles, such as pathogenicity, mutualism and saprophytism, have been very frequent in the course of microbial evolution, and often driven by horizontal gene transfer. Yet, how genomes achieve the ecological transition initiated by the transfer of complex biological traits remains poorly known. Here, we used experimental evolution, genomics, transcriptomics and high-resolution phenotyping to analyze the evolution of the plant pathogen Ralstonia solanacearum into legume symbionts, following the transfer of a natural plasmid encoding the essential mutualistic genes. We show that a regulatory pathway of the recipient R. solanacearum genome involved in extracellular infection of natural hosts was reused to improve intracellular symbiosis with the Mimosa pudica legume. Optimization of intracellular infection capacity was gained through mutations affecting two components of a new regulatory pathway, the transcriptional regulator efpR and a region upstream from the RSc0965-0967 genes of unknown functions. Adaptive mutations caused the downregulation of efpR and the over-expression of a downstream regulatory module, the three unknown genes RSc3146-3148, two of which encoding proteins likely associated to the membrane. This over-expression led to important metabolic and transcriptomic changes and a drastic qualitative and quantitative improvement of nodule intracellular infection. In addition, these adaptive mutations decreased the virulence of the original pathogen. The complete efpR/RSc3146-3148 pathway could only be identified in the genomes of the pathogenic R. solanacearum species complex. Our findings illustrate how the rewiring of a genetic network regulating virulence allows a radically different type of symbiotic interaction and contributes to ecological transitions and trade-offs.
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Affiliation(s)
- Delphine Capela
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Marta Marchetti
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Camille Clérissi
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France.,Microbial Evolutionary Genomics, Institut Pasteur, Paris, France.,CNRS, UMR3525, Paris, France
| | - Anthony Perrier
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Dorian Guetta
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Carine Gris
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Marc Valls
- Department of Genetics, University of Barcelona and Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Edifici CRAG, Campus UAB, Bellaterra, Spain
| | - Alain Jauneau
- Fédération de Recherches Agrobiosciences, Interactions, Biodiversity, Plateforme d'Imagerie TRI, CNRS, UPS, Castanet-Tolosan, France
| | - Stéphane Cruveiller
- CNRS-UMR8030 and Commissariat à l'Energie Atomique et aux Energies Alternatives CEA/DRF/IG/GEN LABGeM, Evry, France
| | - Eduardo P C Rocha
- Microbial Evolutionary Genomics, Institut Pasteur, Paris, France.,CNRS, UMR3525, Paris, France
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A Single Regulator Mediates Strategic Switching between Attachment/Spread and Growth/Virulence in the Plant Pathogen Ralstonia solanacearum. mBio 2017; 8:mBio.00895-17. [PMID: 28951474 PMCID: PMC5615195 DOI: 10.1128/mbio.00895-17] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The PhcA virulence regulator in the vascular wilt pathogen Ralstonia solanacearum responds to cell density via quorum sensing. To understand the timing of traits that enable R. solanacearum to establish itself inside host plants, we created a ΔphcA mutant that is genetically locked in a low-cell-density condition. Comparing levels of gene expression of wild-type R. solanacearum and the ΔphcA mutant during tomato colonization revealed that the PhcA transcriptome includes an impressive 620 genes (>2-fold differentially expressed; false-discovery rate [FDR], ≤0.005). Many core metabolic pathways and nutrient transporters were upregulated in the ΔphcA mutant, which grew faster than the wild-type strain in tomato xylem sap and on dozens of specific metabolites, including 36 found in xylem. This suggests that PhcA helps R. solanacearum to survive in nutrient-poor environmental habitats and to grow rapidly during early pathogenesis. However, after R. solanacearum reaches high cell densities in planta, PhcA mediates a trade-off from maximizing growth to producing costly virulence factors. R. solanacearum infects through roots, and low-cell-density-mode-mimicking ΔphcA cells attached to tomato roots better than the wild-type cells, consistent with their increased expression of several adhesins. Inside xylem vessels, ΔphcA cells formed aberrantly dense mats. Possibly as a result, the mutant could not spread up or down tomato stems as well as the wild type. This suggests that aggregating improves R. solanacearum survival in soil and facilitates infection and that it reduces pathogenic fitness later in disease. Thus, PhcA mediates a second strategic switch between initial pathogen attachment and subsequent dispersal inside the host. PhcA helps R. solanacearum optimally invest resources and correctly sequence multiple steps in the bacterial wilt disease cycle. Ralstonia solanacearum is a destructive soilborne crop pathogen that wilts plants by colonizing their water-transporting xylem vessels. It produces its costly virulence factors only after it has grown to a high population density inside a host. To identify traits that this pathogen needs in other life stages, we studied a mutant that mimics the low-cell-density condition. This mutant (the ΔphcA mutant) cannot sense its own population density. It grew faster than and used many nutrients not available to the wild-type bacterium, including metabolites present in tomato xylem sap. The mutant also attached much better to tomato roots, and yet it failed to spread once it was inside plants because it was trapped in dense mats. Thus, PhcA helps R. solanacearum succeed over the course of its complex life cycle by ensuring avid attachment to plant surfaces and rapid growth early in disease, followed by high virulence and effective dispersal later in disease.
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Yu C, Chen H, Tian F, Yang F, He C. RpoN2- and FliA-regulated fliTX is indispensible for flagellar motility and virulence in Xanthomonas oryzae pv. oryzae. BMC Microbiol 2017; 17:171. [PMID: 28793882 PMCID: PMC5550985 DOI: 10.1186/s12866-017-1083-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 08/02/2017] [Indexed: 12/26/2022] Open
Abstract
Background Bacterial blight of rice caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most important crop diseases in the world. More insights into the mechanistic regulation of bacterial pathogenesis will help us identify novel molecular targets for developing effective disease control strategies. A large flagellar gene cluster is regulated under a three-tiered hierarchy by σ54 factor RpoN2 and its activator FleQ, and σ28 factor FliA. A hypothetical protein gene fliTX is located upstream of rpoN2, however, how it is regulated and how it is related to bacterial behaviors remain to be elucidated. Results Sequence alignment analysis indicated that FliTX in Xoo is less well conserved compared with FliT proteins in Escherichia coli, Salmonella typhimurium, and Pseudomonas fluorescens. Co-transcription of fliTX with a cytosolic chaperone gene fliS and an atypical PilZ-domain gene flgZ in an operon was up-regulated by RpoN2/FleQ and FliA. Significantly shorter filament length and impaired swimming motility were observed in ∆fliTX compared with those in the wildtype strain. ∆fliTX also demonstrated reduced disease lesion length and in planta growth in rice, attenuated ability of induction of hypersensitive response (HR) in nonhost tobacco, and down-regulation of type III secretion system (T3SS)-related genes. In trans expression of fliTX gene in ∆fliTX restored these phenotypes to near wild-type levels. Conclusions This study demonstrates that RpoN2- and FliA-regulated fliTX is indispensible for flagellar motility and virulence and provides more insights into mechanistic regulation of T3SS expression in Xoo. Electronic supplementary material The online version of this article (doi:10.1186/s12866-017-1083-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Chao Yu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Huamin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Fang Tian
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Fenghuan Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Chenyang He
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
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RpoN (σ 54) Is Required for Floc Formation but Not for Extracellular Polysaccharide Biosynthesis in a Floc-Forming Aquincola tertiaricarbonis Strain. Appl Environ Microbiol 2017; 83:AEM.00709-17. [PMID: 28500044 DOI: 10.1128/aem.00709-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 05/08/2017] [Indexed: 11/20/2022] Open
Abstract
Some bacteria are capable of forming flocs, in which bacterial cells become self-flocculated by secreted extracellular polysaccharides and other biopolymers. The floc-forming bacteria play a central role in activated sludge, which has been widely utilized for the treatment of municipal sewage and industrial wastewater. Here, we use a floc-forming bacterium, Aquincolatertiaricarbonis RN12, as a model to explore the biosynthesis of extracellular polysaccharides and the regulation of floc formation. A large gene cluster for exopolysaccharide biosynthesis and a gene encoding the alternative sigma factor RpoN1, one of the four paralogues, have been identified in floc formation-deficient mutants generated by transposon mutagenesis, and the gene functions have been further confirmed by genetic complementation analyses. Interestingly, the biosynthesis of exopolysaccharides remained in the rpoN1-disrupted flocculation-defective mutants, but most of the exopolysaccharides were secreted and released rather than bound to the cells. Furthermore, the expression of exopolysaccharide biosynthesis genes seemed not to be regulated by RpoN1. Taken together, our results indicate that RpoN1 may play a role in regulating the expression of a certain gene(s) involved in the self-flocculation of bacterial cells but not in the biosynthesis and secretion of exopolysaccharides required for floc formation.IMPORTANCE Floc formation confers bacterial resistance to predation of protozoa and plays a central role in the widely used activated sludge process. In this study, we not only identified a large gene cluster for biosynthesis of extracellular polysaccharides but also identified four rpoN paralogues, one of which (rpoN1) is required for floc formation in A. tertiaricarbonis RN12. In addition, this RpoN sigma factor regulates the transcription of genes involved in biofilm formation and swarming motility, as previously shown in other bacteria. However, this RpoN paralogue is not required for the biosynthesis of exopolysaccharides, which are released and dissolved into culture broth by the rpoN1 mutant rather than remaining tightly bound to cells, as observed during the flocculation of the wild-type strain. These results indicate that floc formation is a regulated complex process, and other yet-to-be identified RpoN1-dependent factors are involved in self-flocculation of bacterial cells via exopolysaccharides and/or other biopolymers.
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Puigvert M, Guarischi-Sousa R, Zuluaga P, Coll NS, Macho AP, Setubal JC, Valls M. Transcriptomes of Ralstonia solanacearum during Root Colonization of Solanum commersonii. FRONTIERS IN PLANT SCIENCE 2017; 8:370. [PMID: 28373879 PMCID: PMC5357869 DOI: 10.3389/fpls.2017.00370] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 03/02/2017] [Indexed: 05/03/2023]
Abstract
Bacterial wilt of potatoes-also called brown rot-is a devastating disease caused by the vascular pathogen Ralstonia solanacearum that leads to significant yield loss. As in other plant-pathogen interactions, the first contacts established between the bacterium and the plant largely condition the disease outcome. Here, we studied the transcriptome of R. solanacearum UY031 early after infection in two accessions of the wild potato Solanum commersonii showing contrasting resistance to bacterial wilt. Total RNAs obtained from asymptomatic infected roots were deep sequenced and for 4,609 out of the 4,778 annotated genes in strain UY031 were recovered. Only 2 genes were differentially-expressed between the resistant and the susceptible plant accessions, suggesting that the bacterial component plays a minor role in the establishment of disease. On the contrary, 422 genes were differentially expressed (DE) in planta compared to growth on a synthetic rich medium. Only 73 of these genes had been previously identified as DE in a transcriptome of R. solanacearum extracted from infected tomato xylem vessels. Virulence determinants such as the Type Three Secretion System (T3SS) and its effector proteins, motility structures, and reactive oxygen species (ROS) detoxifying enzymes were induced during infection of S. commersonii. On the contrary, metabolic activities were mostly repressed during early root colonization, with the notable exception of nitrogen metabolism, sulfate reduction and phosphate uptake. Several of the R. solanacearum genes identified as significantly up-regulated during infection had not been previously described as virulence factors. This is the first report describing the R. solanacearum transcriptome directly obtained from infected tissue and also the first to analyze bacterial gene expression in the roots, where plant infection takes place. We also demonstrate that the bacterial transcriptome in planta can be studied when pathogen numbers are low by sequencing transcripts from infected tissue avoiding prokaryotic RNA enrichment.
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Affiliation(s)
- Marina Puigvert
- Department of Genetics, University of BarcelonaBarcelona, Spain
- Centre for Research in Agricultural Genomics CSIC-IRTA, Autonomous University of BarcelonaBellaterra, Spain
| | | | - Paola Zuluaga
- Department of Genetics, University of BarcelonaBarcelona, Spain
- Centre for Research in Agricultural Genomics CSIC-IRTA, Autonomous University of BarcelonaBellaterra, Spain
| | - Núria S. Coll
- Centre for Research in Agricultural Genomics CSIC-IRTA, Autonomous University of BarcelonaBellaterra, Spain
| | - Alberto P. Macho
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences (CAS)Shanghai, China
| | - João C. Setubal
- Department of Biochemistry, University of São PauloSão Paulo, Brazil
| | - Marc Valls
- Department of Genetics, University of BarcelonaBarcelona, Spain
- Centre for Research in Agricultural Genomics CSIC-IRTA, Autonomous University of BarcelonaBellaterra, Spain
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50
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Wang X, Wei Z, Li M, Wang X, Shan A, Mei X, Jousset A, Shen Q, Xu Y, Friman V. Parasites and competitors suppress bacterial pathogen synergistically due to evolutionary trade-offs. Evolution 2017; 71:733-746. [PMID: 27925169 PMCID: PMC5347860 DOI: 10.1111/evo.13143] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Accepted: 11/16/2016] [Indexed: 12/14/2022]
Abstract
Parasites and competitors are important for regulating pathogen densities and subsequent disease dynamics. It is, however, unclear to what extent this is driven by ecological and evolutionary processes. Here, we used experimental evolution to study the eco-evolutionary feedbacks among Ralstonia solanacearum bacterial pathogen, Ralstonia-specific phage parasite, and Bacillus amyloliquefaciens competitor bacterium in the laboratory and plant rhizosphere. We found that while the phage had a small effect on pathogen densities on its own, it considerably increased the R. solanacearum sensitivity to antibiotics produced by B. amyloliquefaciens. Instead of density effects, this synergy was due to phage-driven increase in phage resistance that led to trade-off with the resistance to B. amyloliquefaciens antibiotics. While no evidence was found for pathogen resistance evolution to B. amyloliquefaciens antibiotics, the fitness cost of adaptation (reduced growth) was highest when the pathogen had evolved in the presence of both parasite and competitor. Qualitatively similar patterns were found between laboratory and greenhouse experiments even though the evolution of phage resistance was considerably attenuated in the tomato rhizosphere. These results suggest that evolutionary trade-offs can impose strong constraints on disease dynamics and that combining phages and antibiotic-producing bacteria could be an efficient way to control agricultural pathogens.
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Affiliation(s)
- Xiaofang Wang
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic‐based FertilizersNanjing Agricultural UniversityWeigang 1Nanjing210095China
| | - Zhong Wei
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic‐based FertilizersNanjing Agricultural UniversityWeigang 1Nanjing210095China
| | - Mei Li
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic‐based FertilizersNanjing Agricultural UniversityWeigang 1Nanjing210095China
| | - Xueqi Wang
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic‐based FertilizersNanjing Agricultural UniversityWeigang 1Nanjing210095China
| | - Anqi Shan
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic‐based FertilizersNanjing Agricultural UniversityWeigang 1Nanjing210095China
| | - Xinlan Mei
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic‐based FertilizersNanjing Agricultural UniversityWeigang 1Nanjing210095China
| | - Alexandre Jousset
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic‐based FertilizersNanjing Agricultural UniversityWeigang 1Nanjing210095China
- Institute for Environmental Biology, Ecology & BiodiversityUtrecht UniversityPadualaan 83584CHUtrechtthe Netherlands
| | - Qirong Shen
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic‐based FertilizersNanjing Agricultural UniversityWeigang 1Nanjing210095China
| | - Yangchun Xu
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic‐based FertilizersNanjing Agricultural UniversityWeigang 1Nanjing210095China
| | - Ville‐Petri Friman
- Department of BiologyUniversity of YorkWentworth WayYorkYO10 5DDUnited Kingdom
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