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Gupta G, Chauhan PS, Jha PN, Verma RK, Singh S, Yadav VK, Sahoo DK, Patel A. Secretory molecules from secretion systems fine-tune the host-beneficial bacteria (PGPRs) interaction. Front Microbiol 2024; 15:1355750. [PMID: 38468848 PMCID: PMC10925705 DOI: 10.3389/fmicb.2024.1355750] [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: 12/14/2023] [Accepted: 02/05/2024] [Indexed: 03/13/2024] Open
Abstract
Numerous bacterial species associate with plants through commensal, mutualistic, or parasitic association, affecting host physiology and health. The mechanism for such association is intricate and involves the secretion of multiple biochemical substances through dedicated protein systems called secretion systems SS. Eleven SS pathways deliver protein factors and enzymes in their immediate environment or host cells, as well as in competing microbial cells in a contact-dependent or independent fashion. These SS are instrumental in competition, initiation of infection, colonization, and establishment of association (positive or negative) with host organisms. The role of SS in infection and pathogenesis has been demonstrated for several phytopathogens, including Agrobacterium, Xanthomonas, Ralstonia, and Pseudomonas. Since there is overlap in mechanisms of establishing association with host plants, several studies have investigated the role of SSs in the interaction of plant and beneficial bacteria, including symbiotic rhizobia and plant growth bacteria (PGPB). Therefore, the present review updates the role of different SSs required for the colonization of beneficial bacteria such as rhizobia, Burkholderia, Pseudomonas, Herbaspirillum, etc., on or inside plants, which can lead to a long-term association. Most SS like T3SS, T4SS, T5SS, and T6SS are required for the antagonistic activity needed to prevent competing microbes, including phytopathogens, ameliorate biotic stress in plants, and produce substances for successful colonization. Others are required for chemotaxis, adherence, niche formation, and suppression of immune response to establish mutualistic association with host plants.
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Affiliation(s)
- Garima Gupta
- Institute of Biosciences and Technology, Shri Ramswaroop Memorial University, Barabanki, Uttar Pradesh, India
- Microbial Technologies Group, CSIR-National Botanical Research Institute, Lucknow, Uttar Pradesh, India
| | - Puneet Singh Chauhan
- Microbial Technologies Group, CSIR-National Botanical Research Institute, Lucknow, Uttar Pradesh, India
| | - Prabhat Nath Jha
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, Rajasthan, India
| | - Rakesh Kumar Verma
- Department of Biosciences, SLAS Mody University of Science and Technology, Sikar, Rajasthan, India
| | - Sachidanand Singh
- Department of Biotechnology, School of Energy Technology, Pandit Deendayal Energy University, Gandhinagar, Gujarat, India
| | - Virendra Kumar Yadav
- Department of Lifesciences, Hemchandracharya North Gujarat University, Patan, Gujarat, India
| | - Dipak Kumar Sahoo
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Ashish Patel
- Department of Lifesciences, Hemchandracharya North Gujarat University, Patan, Gujarat, India
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Han X, Huang C, Qi H, Zhu Y, Hu X, Wen Y, Long Y, Xu L, Zhang F. The construction and evaluation of secretory expression engineering bacteria for the trans-Cry3Aa-T-HasA fusion protein against the Monochamus alternatus vector. Front Cell Infect Microbiol 2024; 14:1362961. [PMID: 38465234 PMCID: PMC10921938 DOI: 10.3389/fcimb.2024.1362961] [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: 12/29/2023] [Accepted: 02/06/2024] [Indexed: 03/12/2024] Open
Abstract
Pine wood nematode disease is currently the most deadly forest disease in China, and the Monochamus alternatus is its primary vector. Controlling the M. alternatus is crucial for managing pine wood nematode disease. This study, based on the selected HasA (pGHKW4) secretory expression vector, used electroporation to combine the genetically modified high-toxicity toxin Cry3Aa-T with the entomopathogenic bacterium Yersinia entomophaga isolated from the gut of the M. alternatus. The SDS-PAGE and Western blotting techniques were employed to confirm the toxin protein's secretion capability. The engineered bacteria's genetic stability and effectiveness in controlling M. alternatus were assessed for their insecticidal activity. The results of the SDS-PAGE and Western blotting analyses indicate that the HasA system effectively expresses toxin protein secretion, demonstrates certain genetic stability, and exhibits high insecticidal activity against M. alternatus. This study constructed a highly toxic entomopathogenic engineered bacterial strain against M. alternatus larvae, which holds significant implications for controlling M. alternatus, laying the foundation for subsequent research and application of this strain.
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Affiliation(s)
- Xiaohong Han
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Chenyan Huang
- State Key Laboratory of Biocontrol, School of Ecology, Sun Yat-sen University, Guangzhou, China
| | - Huan Qi
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yukun Zhu
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xinran Hu
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yingxin Wen
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yirong Long
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Lei Xu
- Graduate School of Chinese Academy of Agricultural Sciences, Beijing, China
| | - Feiping Zhang
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
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Nguyen NL, Van Dung V, Van Tung N, Nguyen TKL, Quan ND, Giang TTH, Ngan NTT, Hien NT, Nguyen HH. Draft genome sequencing of halotolerant bacterium Salinicola sp. DM10 unravels plant growth-promoting potentials. 3 Biotech 2023; 13:416. [PMID: 38009164 PMCID: PMC10667196 DOI: 10.1007/s13205-023-03833-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/24/2023] [Indexed: 11/28/2023] Open
Abstract
In this study, strain DM10 was isolated from mangrove roots and characterized as a halotolerant plant growth-promoting bacterium. Strain DM10 exhibited the ability to solubilize phosphate, produce siderophore, show 1-aminocyclopropane-1-carboxylic acid deaminase activity, and hydrolyze starch. The rice plants subjected to a treatment of NaCl (200 mM) and inoculated with strain DM10 showed an improvement in the shoot length, root length, and dried weight, when compared to those exposed solely to saline treatment. The comprehensive genome sequencing of strain DM10 revealed a genome spanning of 4,171,745 bp, harboring 3626 protein coding sequences. Within its genome, strain DM10 possesses genes responsible for both salt-in and salt-out strategies, indicative of a robust genetic adaptation aimed at fostering salt tolerance. Additionally, the genome encodes genes involved in phosphate solubilization, such as the synthesis of gluconic acid, high-affinity phosphate transport systems, and alkaline phosphatase. In the genome of DM10, we identified the acdS gene, responsible for encoding 1-aminocyclopropane-1-carboxylate deaminase, as well as the amy1A gene, which encodes α-amylase. Furthermore, the genome of DM10 contains sequences associated with the iron (3+)-hydroxamate and iron uptake clusters, responsible for siderophore production. Such data provide a deep understanding of the mechanism employed by strain DM10 to combat osmotic and salinity stress, facilitate plant growth, and elucidate its molecular-level behaviors.
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Affiliation(s)
- Ngoc-Lan Nguyen
- Institute of Genome Research, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi Vietnam
- Graduate of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi Vietnam
| | - Vu Van Dung
- Institute of Genome Research, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi Vietnam
- Graduate of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi Vietnam
| | - Nguyen Van Tung
- Institute of Genome Research, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi Vietnam
- Graduate of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi Vietnam
| | - Thi Kim Lien Nguyen
- Institute of Genome Research, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi Vietnam
| | - Nguyen Duc Quan
- Institute of Genome Research, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi Vietnam
| | - Tran Thi Huong Giang
- Institute of Genome Research, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi Vietnam
| | - Nguyen Thi Thanh Ngan
- Institute of Genome Research, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi Vietnam
- Graduate of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi Vietnam
| | - Nguyen Thanh Hien
- Institute of Genome Research, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi Vietnam
| | - Huy-Hoang Nguyen
- Institute of Genome Research, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi Vietnam
- Graduate of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi Vietnam
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Yuen ELH, Shepherd S, Bozkurt TO. Traffic Control: Subversion of Plant Membrane Trafficking by Pathogens. ANNUAL REVIEW OF PHYTOPATHOLOGY 2023; 61:325-350. [PMID: 37186899 DOI: 10.1146/annurev-phyto-021622-123232] [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] [Indexed: 05/17/2023]
Abstract
Membrane trafficking pathways play a prominent role in plant immunity. The endomembrane transport system coordinates membrane-bound cellular organelles to ensure that immunological components are utilized effectively during pathogen resistance. Adapted pathogens and pests have evolved to interfere with aspects of membrane transport systems to subvert plant immunity. To do this, they secrete virulence factors known as effectors, many of which converge on host membrane trafficking routes. The emerging paradigm is that effectors redundantly target every step of membrane trafficking from vesicle budding to trafficking and membrane fusion. In this review, we focus on the mechanisms adopted by plant pathogens to reprogram host plant vesicle trafficking, providing examples of effector-targeted transport pathways and highlighting key questions for the field to answer moving forward.
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Affiliation(s)
- Enoch Lok Him Yuen
- Department of Life Sciences, Imperial College, London, United Kingdom; , ,
| | - Samuel Shepherd
- Department of Life Sciences, Imperial College, London, United Kingdom; , ,
| | - Tolga O Bozkurt
- Department of Life Sciences, Imperial College, London, United Kingdom; , ,
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Anderson JC. Ill Communication: Host Metabolites as Virulence-Regulating Signals for Plant-Pathogenic Bacteria. ANNUAL REVIEW OF PHYTOPATHOLOGY 2023; 61:49-71. [PMID: 37253693 DOI: 10.1146/annurev-phyto-021621-114026] [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: 06/01/2023]
Abstract
Plant bacterial pathogens rely on host-derived signals to coordinate the deployment of virulence factors required for infection. In this review, I describe how diverse plant-pathogenic bacteria detect and respond to plant-derived metabolic signals for the purpose of virulence gene regulation. I highlight examples of how pathogens perceive host metabolites through membrane-localized receptors as well as intracellular response mechanisms. Furthermore, I describe how individual strains may coordinate their virulence using multiple distinct host metabolic signals, and how plant signals may positively or negatively regulate virulence responses. I also describe how plant defenses may interfere with the perception of host metabolites as a means to dampen pathogen virulence. The emerging picture is that recognition of host metabolic signals for the purpose of virulence gene regulation represents an important primary layer of interaction between pathogenic bacteria and host plants that shapes infection outcomes.
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Affiliation(s)
- Jeffrey C Anderson
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA;
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6
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Plant roots temporarily leak iron to promote colonization by beneficial rhizobacterium. Nat Microbiol 2023; 8:1390-1391. [PMID: 37438516 DOI: 10.1038/s41564-023-01441-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
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Liu Y, Shu X, Chen L, Zhang H, Feng H, Sun X, Xiong Q, Li G, Xun W, Xu Z, Zhang N, Pieterse CMJ, Shen Q, Zhang R. Plant commensal type VII secretion system causes iron leakage from roots to promote colonization. Nat Microbiol 2023; 8:1434-1449. [PMID: 37248429 DOI: 10.1038/s41564-023-01402-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 05/04/2023] [Indexed: 05/31/2023]
Abstract
Competition for iron is an important factor for microbial niche establishment in the rhizosphere. Pathogenic and beneficial symbiotic bacteria use various secretion systems to interact with their hosts and acquire limited resources from the environment. Bacillus spp. are important plant commensals that encode a type VII secretion system (T7SS). However, the function of this secretion system in rhizobacteria-plant interactions is unclear. Here we use the beneficial rhizobacterium Bacillus velezensis SQR9 to show that the T7SS and the major secreted protein YukE are critical for root colonization. In planta experiments and liposome-based experiments demonstrate that secreted YukE inserts into the plant plasma membrane and causes root iron leakage in the early stage of inoculation. The increased availability of iron promotes root colonization by SQR9. Overall, our work reveals a previously undescribed role of the T7SS in a beneficial rhizobacterium to promote colonization and thus plant-microbe interactions.
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Affiliation(s)
- Yunpeng Liu
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China (the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
| | - Xia Shu
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China (the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, P.R. China
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Lin Chen
- Experimental Center of Forestry in North China, Chinese Academy of Forestry, Beijing, P. R. China
| | - Huihui Zhang
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, P.R. China
| | - Haichao Feng
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, P.R. China
| | - Xiting Sun
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China (the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qin Xiong
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China (the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Guangqi Li
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China (the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Weibing Xun
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, P.R. China
| | - Zhihui Xu
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, P.R. China
| | - Nan Zhang
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, P.R. China
| | - Corné M J Pieterse
- Plant-Microbe Interactions, Department of Biology, Utrecht University, Utrecht, the Netherlands
| | - Qirong Shen
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, P.R. China
| | - Ruifu Zhang
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China (the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, P.R. China.
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8
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Miranda RP, Turrini PCG, Bonadio DT, Zerillo MM, Berselli AP, Creste S, Van Sluys MA. Genome Organization of Four Brazilian Xanthomonas albilineans Strains Does Not Correlate with Aggressiveness. Microbiol Spectr 2023; 11:e0280222. [PMID: 37052486 PMCID: PMC10269729 DOI: 10.1128/spectrum.02802-22] [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: 08/06/2022] [Accepted: 03/03/2023] [Indexed: 04/14/2023] Open
Abstract
An integrative approach combining genomics, transcriptomics, and cell biology is presented to address leaf scald disease, a major problem for the sugarcane industry. To gain insight into the biology of the causal agent, the complete genome sequences of four Brazilian Xanthomonas albilineans strains with differing virulence capabilities are presented and compared to the GPEPC73 reference strain and FJ1. Based on the aggressiveness index, different strains were compared: Xa04 and Xa11 are highly aggressive, Xa26 is intermediate, and Xa21 is the least, while, based on genome structure, Xa04 shares most of its genomic features with Xa26, and Xa11 share most of its genomic features with Xa21. In addition to presenting more clustered regularly interspaced short palindromic repeats (CRISPR) clusters, four more novel prophage insertions are present than the previously sequenced GPEPC73 and FJ1 strains. Incorporating the aggressiveness index and in vitro cell biology into these genome features indicates that disease establishment is not a result of a single determinant factor, as in most other Xanthomonas species. The Brazilian strains lack the previously described plasmids but present more prophage regions. In pairs, the most virulent and the least virulent share unique prophages. In vitro transcriptomics shed light on the 54 most highly expressed genes among the 4 strains compared to ribosomal proteins (RPs), of these, 3 outer membrane proteins. Finally, comparative albicidin inhibition rings and in vitro growth curves of the four strains also do not correlate with pathogenicity. In conclusion, the results disclose that leaf scald disease is not associated with a single shared characteristic between the most or the least pathogenic strains. IMPORTANCE An integrative approach is presented which combines genomics, transcriptomics, and cell biology to address leaf scald disease. The results presented here disclose that the disease is not associated with a single shared characteristic between the most pathogenic strains or a unique genomic pattern. Sequence data from four Brazilian strains are presented that differ in pathogenicity index: Xa04 and Xa11 are highly virulent, Xa26 is intermediate, and Xa21 is the least pathogenic strain, while, based on genome structure, Xa04 shares with Xa26, and Xa11 shares with X21 most of the genome features. Other than presenting more CRISPR clusters and prophages than the previously sequenced strains, the integration of aggressiveness and cell biology points out that disease establishment is not a result of a single determinant factor as in other xanthomonads.
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Affiliation(s)
- Raquel P. Miranda
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo (USP), Butanta, São Paulo, Brazil
| | - Paula C. G. Turrini
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo (USP), Butanta, São Paulo, Brazil
| | - Dora T. Bonadio
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo (USP), Butanta, São Paulo, Brazil
| | - Marcelo M. Zerillo
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo (USP), Butanta, São Paulo, Brazil
| | - Arthur P. Berselli
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo (USP), Butanta, São Paulo, Brazil
| | - Silvana Creste
- Centro de Cana, Instituto Agronômico de Campinas (IAC), Campinas, São Paulo, Brazil
| | - Marie-Anne Van Sluys
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo (USP), Butanta, São Paulo, Brazil
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9
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Fernandez J. The Phantom Menace: latest findings on effector biology in the rice blast fungus. ABIOTECH 2023; 4:140-154. [PMID: 37581025 PMCID: PMC10423181 DOI: 10.1007/s42994-023-00099-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 02/11/2023] [Indexed: 08/16/2023]
Abstract
Magnaporthe oryzae is a hemibiotrophic fungus responsible for the economically devastating and recalcitrant rice blast disease. However, the blast fungus is not only restricted to rice plants as it can also infect wheat, millet, and other crops. Despite previous outstanding discoveries aimed to understand and control the disease, the fungus remains one of the most important pathogens that threatens global food security. To cause disease, M. oryzae initiates morphological changes to attach, penetrate, and colonize rice cells, all while suppressing plant immune defenses that would otherwise hinder its proliferation. As such, M. oryzae actively secretes a battery of small proteins called "effectors" to manipulate host machinery. In this review, we summarize the latest findings in effector identification, expression, regulation, and functionality. We review the most studied effectors and their roles in pathogenesis. Additionally, we discern the current methodologies to structurally catalog effectors, and we highlight the importance of climate change and its impact on the future of rice blast disease.
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Affiliation(s)
- Jessie Fernandez
- Department of Microbiology and Cell Science at University of Florida-Institute of Food and Agricultural Science, Gainesville, FL 32611 USA
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10
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Maphosa S, Moleleki LN, Motaung TE. Bacterial secretion system functions: evidence of interactions and downstream implications. MICROBIOLOGY (READING, ENGLAND) 2023; 169. [PMID: 37083586 DOI: 10.1099/mic.0.001326] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
Unprecedented insights into the biology and functions of bacteria have been and continue to be gained through studying bacterial secretion systems in isolation. This method, however, results in our understanding of the systems being primarily based on the idea that they operate independently, ignoring the subtleties of downstream interconnections. Gram-negative bacteria are naturally able to adapt to and navigate their frequently varied and dynamic surroundings, mostly because of the covert connections between secretion systems. Therefore, to comprehend some of the linked downstream repercussions for organisms that follow this discourse, it is vital to have mechanistic insights into how the intersecretion system functions in bacterial rivalry, virulence, and survival, among other things. To that purpose, this paper discusses a few key instances of molecular antagonistic and interdependent relationships between bacterial secretion systems and their produced functional products.
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Affiliation(s)
- Silindile Maphosa
- Division of Microbiology, Department of Biochemistry, Genetics, and Microbiology, University of Pretoria, Hatfield, Pretoria, South Africa
- Department of Plant and Soil Sciences, University of Pretoria, Hatfield, Pretoria, South Africa
- Forestry and Agricultural Biotechnology Institute, University of Pretoria, Hatfield, Pretoria, South Africa
| | - Lucy N Moleleki
- Division of Microbiology, Department of Biochemistry, Genetics, and Microbiology, University of Pretoria, Hatfield, Pretoria, South Africa
- Forestry and Agricultural Biotechnology Institute, University of Pretoria, Hatfield, Pretoria, South Africa
| | - Thabiso E Motaung
- Division of Microbiology, Department of Biochemistry, Genetics, and Microbiology, University of Pretoria, Hatfield, Pretoria, South Africa
- Forestry and Agricultural Biotechnology Institute, University of Pretoria, Hatfield, Pretoria, South Africa
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11
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Sharma A, Gupta AK, Devi B. Current trends in management of bacterial pathogens infecting plants. Antonie Van Leeuwenhoek 2023; 116:303-326. [PMID: 36683073 DOI: 10.1007/s10482-023-01809-0] [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: 09/08/2022] [Accepted: 01/08/2023] [Indexed: 01/24/2023]
Abstract
Plants are continuously challenged by different pathogenic microbes that reduce the quality and quantity of produce and therefore pose a serious threat to food security. Among them bacterial pathogens are known to cause disease outbreaks with devastating economic losses in temperate, tropical and subtropical regions throughout the world. Bacteria are structurally simple prokaryotic microorganisms and are diverse from a metabolic standpoint. Bacterial infection process mainly involves successful attachment or penetration by using extracellular enzymes, type secretion systems, toxins, growth regulators and by exploiting different molecules that modulate plant defence resulting in successful colonization. Theses bacterial pathogens are extremely difficult to control as they develop resistance to antibiotics. Therefore, attempts are made to search for innovative methods of disease management by the targeting bacterial virulence and manipulating the genes in host plants by exploiting genome editing methods. Here, we review the recent developments in bacterial disease management including the bioactive antimicrobial compounds, bacteriophage therapy, quorum-quenching mediated control, nanoparticles and CRISPR/Cas based genome editing techniques for bacterial disease management. Future research should focus on implementation of smart delivery systems and consumer acceptance of these innovative methods for sustainable disease management.
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Affiliation(s)
- Aditi Sharma
- College of Horticulture and Forestry, Thunag- Mandi, Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh, 173 230, India.
| | - A K Gupta
- Department of Plant Pathology, Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh, 173 230, India
| | - Banita Devi
- Department of Plant Pathology, Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh, 173 230, India
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12
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Zhao M, Shin GY, Stice S, Bown JL, Coutinho T, Metcalf WW, Gitaitis R, Kvitko B, Dutta B. A Novel Biosynthetic Gene Cluster Across the Pantoea Species Complex Is Important for Pathogenicity in Onion. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2023; 36:176-188. [PMID: 36534063 PMCID: PMC10433531 DOI: 10.1094/mpmi-08-22-0165-r] [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] [Indexed: 06/01/2023]
Abstract
Onion center rot is caused by at least four species of genus Pantoea (P. ananatis, P. agglomerans, P. allii, and P. stewartii subsp. indologenes). Critical onion pathogenicity determinants for P. ananatis were recently described, but whether those determinants are common among other onion-pathogenic Pantoea species remains unknown. In this work, we report onion pathogenicity determinants in P. stewartii subsp. indologenes and P. allii. We identified two distinct secondary metabolite biosynthetic gene clusters present separately in different strains of onion-pathogenic P. stewartii subsp. indologenes. One cluster is similar to the previously described HiVir phosphonate biosynthetic cluster identified in P. ananatis and another is a novel putative phosphonate biosynthetic gene cluster, which we named Halophos. The Halophos gene cluster was also identified in P. allii strains. Both clusters are predicted to be phosphonate biosynthetic clusters based on the presence of a characteristic phosphoenolpyruvate phosphomutase (pepM) gene. The deletion of the pepM gene from either HiVir or Halophos clusters in P. stewartii subsp. indologenes caused loss of necrosis on onion leaves and red onion scales and resulted in significantly lower bacterial populations compared with the corresponding wild-type and complemented strains. Seven (halB to halH) of 11 genes (halA to halK) in the Halophos gene cluster are required for onion necrosis phenotypes. The onion nonpathogenic strain PNA15-2 (P. stewartii subsp. indologenes) gained the capacity to cause foliar necrosis on onion via exogenous expression of a minimal seven-gene Halophos cluster (genes halB to halH). Furthermore, cell-free culture filtrates of PNA14-12 expressing the intact Halophos gene cluster caused necrosis on onion leaves consistent with the presence of a secreted toxin. Based on the similarity of proteins to those with experimentally determined functions, we are able to predict most of the steps in Halophos biosynthesis. Together, these observations indicate that production of the toxin phosphonate seems sufficient to account for virulence of a variety of different Pantoea strains, although strains differ in possessing a single but distinct phosphonate biosynthetic cluster. Overall, this is the first report of onion pathogenicity determinants in P. stewartii subsp. indologenes and P. allii. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Mei Zhao
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, P. R. China
- Department of Plant Pathology, University of Georgia, Tifton GA USA
| | - Gi Yoon Shin
- Department of Plant Pathology, University of Georgia, Athens GA USA
| | - Shaun Stice
- Department of Plant Pathology, University of Georgia, Athens GA USA
| | - Jonathon Luke Bown
- Department of Microbiology, University of Illinois, Urbana-Champaign, IL
| | - Teresa Coutinho
- The Genomics Research Institute, University of Pretoria, Hatfield, South Africa
| | - William W. Metcalf
- Department of Microbiology, University of Illinois, Urbana-Champaign, IL
| | - Ron Gitaitis
- Department of Plant Pathology, University of Georgia, Tifton GA USA
| | - Brian Kvitko
- Department of Plant Pathology, University of Georgia, Athens GA USA
| | - Bhabesh Dutta
- Department of Plant Pathology, University of Georgia, Tifton GA USA
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Myers BK, Shin GY, Agarwal G, Stice SP, Gitaitis RD, Kvitko BH, Dutta B. Genome-wide association and dissociation studies in Pantoea ananatis reveal potential virulence factors affecting Allium porrum and Allium fistulosum × Allium cepa hybrid. Front Microbiol 2023; 13:1094155. [PMID: 36817114 PMCID: PMC9933511 DOI: 10.3389/fmicb.2022.1094155] [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: 11/09/2022] [Accepted: 12/30/2022] [Indexed: 02/05/2023] Open
Abstract
Pantoea ananatis is a member of a Pantoea species complex that causes center rot of bulb onions (A. cepa) and also infects other Allium crops like leeks (Allium porrum), chives (Allium schoenoprasum), bunching onion or Welsh onion (Allium fistulosum), and garlic (Allium sativum). This pathogen relies on a chromosomal phosphonate biosynthetic gene cluster (HiVir) and a plasmid-borne thiosulfinate tolerance cluster (alt) for onion pathogenicity and virulence, respectively. However, pathogenicity and virulence factors associated with other Allium species remain unknown. We used phenotype-dependent genome-wide association (GWAS) and phenotype-independent gene-pair coincidence (GPC) analyses on a panel of diverse 92 P. ananatis strains, which were inoculated on A. porrum and A. fistulosum × A. cepa under greenhouse conditions. Phenotypic assays showed that, in general, these strains were more aggressive on A. fistulosum × A. cepa as opposed to A. porrum. Of the 92 strains, only six showed highly aggressive foliar lesions on A. porrum compared to A. fistulosum × A. cepa. Conversely, nine strains showed highly aggressive foliar lesions on A. fistulosum × A. cepa compared to A. porrum. These results indicate that there are underlying genetic components in P. ananatis that may drive pathogenicity in these two Allium spp. Based on GWAS for foliar pathogenicity, 835 genes were associated with P. ananatis' pathogenicity on A. fistulosum × A. cepa whereas 243 genes were associated with bacterial pathogenicity on A. porrum. The Hivir as well as the alt gene clusters were identified among these genes. Besides the 'HiVir' and the alt gene clusters that are known to contribute to pathogenicity and virulence from previous studies, genes annotated with functions related to stress responses, a potential toxin-antitoxin system, flagellar-motility, quorum sensing, and a previously described phosphonoglycan biosynthesis (pgb) cluster were identified. The GPC analysis resulted in the identification of 165 individual genes sorted into 39 significant gene-pair association components and 255 genes sorted into 50 significant gene-pair dissociation components. Within the coincident gene clusters, several genes that occurred on the GWAS outputs were associated with each other but dissociated with genes that did not appear in their respective GWAS output. To focus on candidate genes that could explain the difference in virulence between hosts, a comparative genomics analysis was performed on five P. ananatis strains that were differentially pathogenic on A. porrum or A. fistulosum × A. cepa. Here, we found a putative type III secretion system, and several other genes that occurred on both GWAS outputs of both Allium hosts. Further, we also demonstrated utilizing mutational analysis that the pepM gene in the HiVir cluster is important than the pepM gene in the pgb cluster for P. ananatis pathogenicity in A. fistulosum × A. cepa and A. porrum. Overall, our results support that P. ananatis may utilize a common set of genes or gene clusters to induce symptoms on A. fistulosum × A. cepa foliar tissue as well as A. cepa but implicates additional genes for infection on A. porrum.
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Affiliation(s)
- Brendon K. Myers
- Department of Plant Pathology, The University of Georgia, Tifton, GA, United States
| | - Gi Yoon Shin
- Department of Plant Pathology, The University of Georgia, Athens, GA, United States
| | - Gaurav Agarwal
- Department of Plant Pathology, The University of Georgia, Tifton, GA, United States
| | - Shaun P. Stice
- Department of Plant Pathology, The University of Georgia, Athens, GA, United States
| | - Ronald D. Gitaitis
- Department of Plant Pathology, The University of Georgia, Tifton, GA, United States
| | - Brian H. Kvitko
- Department of Plant Pathology, The University of Georgia, Athens, GA, United States
| | - Bhabesh Dutta
- Department of Plant Pathology, The University of Georgia, Tifton, GA, United States,*Correspondence: Bhabesh Dutta, ✉
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Zhao M, Tyson C, Gitaitis R, Kvitko B, Dutta B. Rouxiella badensis, a new bacterial pathogen of onion causing bulb rot. Front Microbiol 2022; 13:1054813. [DOI: 10.3389/fmicb.2022.1054813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/10/2022] [Indexed: 12/02/2022] Open
Abstract
Onion bulb rot can be caused by multiple plant pathogens including bacterial pathogens. During our routine survey of commercial onion farms in 2014, 2020, and 2021, seven putative Rouxiella spp. strains were isolated from symptomatic onion samples in Georgia, United States. Upon fulfilling Koch’s postulates on onion, a genome analysis was conducted. Whole-genome indices (ANI and dDDH) showed that the strains belonged to Rouxiella badensis. Although the seven R. badensis strains were not pathogenic on onion foliage, the strains were able to cause bulb rot and could also produce necrotic lesions in a red onion scale assay. R. badensis populations increased significantly and to a level comparable to P. ananatis PNA 97-1R in a red onion scale infection assay. The core-genome analysis grouped all onion R. badensis strains from Georgia together, and distinct from R. badensis strains isolated from other sources and locations. Based on the genome analysis of strains (from the current study and available genomes in the repository), type I, III (Ssa-Esc and Inv-Mxi-Spa types), and V secretion systems are present in R. badensis genomes, while type II, IV, and VI secretion systems are absent. However, various secondary metabolite gene clusters were identified from R. badensis genomes, and a thiol/redox-associated enzyme gene cluster similar to the Pantoea alt cluster mediating thiosulfinate tolerance was also present in onion strains of R. badensis. This is the first report of R. badensis as a plant pathogen.
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Suraby EJ, Sruthi KB, Antony G. Genome-wide identification of type III effectors and other virulence factors in Ralstonia pseudosolanacearum causing bacterial wilt in ginger (Zingiber officinale). Mol Genet Genomics 2022; 297:1371-1388. [PMID: 35879566 DOI: 10.1007/s00438-022-01925-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 07/04/2022] [Indexed: 10/16/2022]
Abstract
Ralstonia pseudosolanacearum causes bacterial wilt in ginger, reducing ginger production worldwide. We sequenced the whole genome of a highly virulent phylotype I, race 4, biovar 3 Ralstonia pseudosolanacearum strain GRsMep isolated from a severely infected ginger field in India. R. pseudosolanacearum GRsMep genome is organised into two replicons: chromosome and megaplasmid with a total genome size of 5,810,605 bp. This strain encodes approximately 72 effectors which include a combination of core effectors as well as highly variable, diverse repertoire of type III effectors. Comparative genome analysis with GMI1000 identified conservation in the genes involved in the general virulence mechanism. Our analysis identified type III effectors, RipBJ and RipBO as present in GRsMep but absent in the reported genomes of other strains infecting Zingiberaceae family. GRsMep contains 126 unique genes when compared to the pangenome of the Ralstonia strains that infect the Zingiberaceae family. The whole-genome data of R. pseudosolanacearum strain will serve as a resource for exploring the evolutionary processes that structure and regulate the virulence determinants of the strain. Pathogenicity testing of the transposon insertional mutant library of GRsMep through virulence assay on ginger plants identified a few candidate virulence determinants specific to bacterial wilt in ginger.
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Affiliation(s)
- Erinjery Jose Suraby
- Department of Plant Science, Central University of Kerala, Periye, 671320, Kasaragod, Kerala, India
| | - K Bharathan Sruthi
- Department of Plant Science, Central University of Kerala, Periye, 671320, Kasaragod, Kerala, India
| | - Ginny Antony
- Department of Plant Science, Central University of Kerala, Periye, 671320, Kasaragod, Kerala, India.
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Xu S, Zhang Z, Xie X, Shi Y, Chai A, Fan T, Li B, Li L. Comparative genomics provides insights into the potential biocontrol mechanism of two Lysobacter enzymogenes strains with distinct antagonistic activities. Front Microbiol 2022; 13:966986. [PMID: 36033849 PMCID: PMC9410377 DOI: 10.3389/fmicb.2022.966986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 07/27/2022] [Indexed: 11/29/2022] Open
Abstract
Lysobacter enzymogenes has been applied as an abundant beneficial microorganism to control plant disease; however, most L. enzymogenes strains have been mainly reported to control fungal diseases, not bacterial diseases. In this study, two L. enzymogenes strains were characterized, of which CX03 displayed a broad spectrum of antagonistic activities toward multiple bacteria, while CX06 exhibited a broad spectrum of antagonistic activities toward diverse fungi and oomycete, and the whole genomes of the two strains were sequenced and compared. The genome annotation showed that the CX03 genome comprised a 5,947,018 bp circular chromosome, while strain CX06 comprised a circular 6,206,196 bp chromosome. Phylogenetic analysis revealed that CX03 had a closer genetic relationship with L. enzymogenes ATCC29487T and M497-1, while CX06 was highly similar to L. enzymogenes C3. Functional gene annotation analyses of the two L. enzymogenes strains showed that many genes or gene clusters associated with the biosynthesis of different secondary metabolites were found in strains CX03 and CX06, which may be responsible for the different antagonistic activities against diverse plant pathogens. Moreover, comparative genomic analysis revealed the difference in bacterial secretory systems between L. enzymogenes strains CX03 and CX06. In addition, numerous conserved genes related to siderophore biosynthesis, quorum sensing, two-component systems, flagellar biosynthesis and chemotaxis were also identified in the genomes of strains CX03 and CX06. Most reported L. enzymogenes strains were proven mainly to suppress fungi, while CX03 exhibited direct inhibitory activities toward plant bacterial pathogens and showed an obvious role in managing bacterial disease. This study provides a novel understanding of the biocontrol mechanisms of L. enzymogenes, and reveals great potential for its application in plant disease control.
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17
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Wang P, Lopes LD, Lopez-Guerrero MG, van Dijk K, Alvarez S, Riethoven JJ, Schachtman DP. Natural variation in root exudation of GABA and DIMBOA impacts the maize root endosphere and rhizosphere microbiomes. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:5052-5066. [PMID: 35552399 DOI: 10.1093/jxb/erac202] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
Root exudates are important for shaping root-associated microbiomes. However, studies on a wider range of metabolites in exudates are required for a comprehensive understanding about their influence on microbial communities. We identified maize inbred lines that differ in exudate concentrations of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) and γ-aminobutyric acid (GABA) using a semi-hydroponic system. These lines were grown in the field to determine the changes in microbial diversity and gene expression due to varying concentrations of DIMBOA and GABA in exudates using 16S rRNA amplicon sequencing and metatranscriptomics. Results showed individual and interaction effects of DIMBOA and GABA on the rhizosphere and root endosphere β-diversity, most strongly at the V10 growth stage. The main bacterial families affected by both compounds were Ktedonobacteraceae and Xanthomonadaceae. Higher concentrations of DIMBOA in exudates affected the rhizosphere metatranscriptome, enriching for metabolic pathways associated with plant disease. This study validated the use of natural variation within plant species as a powerful approach for understanding the role of root exudates on microbiome selection. We also showed that a semi-hydroponic system can be used to identify maize genotypes that differ in GABA and DIMBOA exudate concentrations under field conditions. The impact of GABA exudation on root-associated microbiomes is shown for the first time.
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Affiliation(s)
- Peng Wang
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, USA and Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, USA
- Nebraska Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Lucas Dantas Lopes
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, USA and Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, USA
- Nebraska Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | | | - Karin van Dijk
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Sophie Alvarez
- Nebraska Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA
- Proteomics and Metabolomics Facility, Nebraska Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Jean-Jack Riethoven
- Nebraska Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA
- Bioinformatics Core Facility, Nebraska Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Daniel P Schachtman
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, USA and Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, USA
- Nebraska Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA
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18
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Miao X, Liu C, Liu M, Han X, Zhu L, Bai X. The role of pipe biofilms on dissemination of viral pathogens and virulence factor genes in a full-scale drinking water supply system. JOURNAL OF HAZARDOUS MATERIALS 2022; 432:128694. [PMID: 35316639 DOI: 10.1016/j.jhazmat.2022.128694] [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: 12/11/2021] [Revised: 02/24/2022] [Accepted: 03/10/2022] [Indexed: 06/14/2023]
Abstract
Water is an important medium for virus transmission and viral pathogens are increasingly appreciated as a significant water safety issue. However, the effect of pipe biofilms on viral pathogens remains unclear. This research aimed to investigate the dissemination of viruses in a full-scale drinking water supply system (DWSS) and the effect of pipe biofilms on viral pathogens in bulking water. Viral pathogens, pathogenic viral hosts, and viral virulence factors (VFs) were found to disseminate from source water to tap water. The proportion of virus and viral VFs in the biofilm was far less than that in water. The contribution of biofilms in pipe wall to viruses and viral VFs in bulking water was less than 4%, and viruses in the biofilm had no obvious effect on pathogenic viruses in water. Dominant viruses carrying VFs changed from Cyanobacteria virus to Mycobacterium virus after advanced water treatment. Mycobacterium and organics were identified as the key factors influencing composition and abundance of viral VFs, which could explain 41.1% of the variation in viral virulence in the water supply system. Host bacteria and organics may be used as the key targets to control the risk of viruses in DWSSs.
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Affiliation(s)
- Xiaocao Miao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Chenxu Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Mingkun Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Xue Han
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Lingling Zhu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Xiaohui Bai
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China.
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Xu S, Zhao Y, Peng Y, Shi Y, Xie X, Chai A, Li B, Li L. Comparative Genomics Assisted Functional Characterization of Rahnella aceris ZF458 as a Novel Plant Growth Promoting Rhizobacterium. Front Microbiol 2022; 13:850084. [PMID: 35444623 PMCID: PMC9015054 DOI: 10.3389/fmicb.2022.850084] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 02/24/2022] [Indexed: 11/25/2022] Open
Abstract
Many Rahnella strains have been widely described as plant growth-promoting rhizobacteria with the potential to benefit plant growth and protect plants from pathogens. R. aceris ZF458 is a beneficial plant bacterium isolated from swamp soil with the potential for biocontrol. Strain ZF458 has shown broad-spectrum antagonistic activities against a variety of plant pathogens and exhibited a dramatic effect on controlling Agrobacterium tumefaciens in sunflowers. The R. aceris ZF458 genome sequence contained a 4,861,340-bp circular chromosome and two plasmids, with an average G + C content of 52.20%. Phylogenetic analysis demonstrated that R. aceris ZF458 was closely related to R. aceris SAP-19. Genome annotation and comparative genomics identified the conservation and specificity of large numbers of genes associated with nitrogen fixation, plant growth hormone production, organic acid biosynthesis and pyrroloquinoline quinone production that specific to benefiting plants in strain ZF458. In addition, numerous conserved genes associated with environmental adaption, including the bacterial secretion system, selenium metabolism, two-component system, flagella biosynthesis, chemotaxis, and acid resistance, were also identified in the ZF458 genome. Overall, this was the first study to systematically analyze the genes linked with plant growth promotion and environmental adaption in R. aceris. The aim of this study was to derive genomic information that would provide an in-depth insight of the mechanisms of plant growth-promoting rhizobacteria, and could be further exploited to improve the application of R. aceris ZF458 in the agriculture field.
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Affiliation(s)
- Shuai Xu
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yurong Zhao
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yue Peng
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yanxia Shi
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xuewen Xie
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ali Chai
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Baoju Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lei Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
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20
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Deb S, Madhavan VN, Gokulan CG, Patel HK, Sonti RV. Arms and ammunitions: effectors at the interface of rice and it's pathogens and pests. RICE (NEW YORK, N.Y.) 2021; 14:94. [PMID: 34792681 PMCID: PMC8602583 DOI: 10.1186/s12284-021-00534-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 11/06/2021] [Indexed: 06/13/2023]
Abstract
The plant immune system has evolved to resist attack by pathogens and pests. However, successful phytopathogens deliver effector proteins into plant cells where they hijack the host cellular machinery to suppress the plant immune responses and promote infection. This manipulation of the host cellular pathways is done by the pathogen using various enzymatic activities, protein- DNA or protein- protein interactions. Rice is one the major economically important crops and its yield is affected by several pathogens and pests. In this review, we summarize the various effectors at the plant- pathogen/ pest interface for the major pathogens and pests of rice, specifically, on the mode of action and target genes of the effector proteins. We then compare this across the major rice pathogens and pests in a bid to understand probable conserved pathways which are under attack from pathogens and pests in rice. This analysis highlights conserved patterns of effector action, as well as unique host pathways targeted by the pathogens and pests.
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Affiliation(s)
- Sohini Deb
- CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB), Hyderabad, 500007 India
- Present Address: Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
| | | | - C. G. Gokulan
- CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB), Hyderabad, 500007 India
| | - Hitendra K. Patel
- CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB), Hyderabad, 500007 India
| | - Ramesh V. Sonti
- CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB), Hyderabad, 500007 India
- Present Address: Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, 517507 India
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21
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Maphosa S, Moleleki LN. Isolation and Characterization of Outer Membrane Vesicles of Pectobacterium brasiliense 1692. Microorganisms 2021; 9:1918. [PMID: 34576813 PMCID: PMC8469291 DOI: 10.3390/microorganisms9091918] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/01/2021] [Accepted: 09/03/2021] [Indexed: 12/15/2022] Open
Abstract
Pectobacterium brasiliense (Pbr) 1692 is an aggressive phytopathogen affecting a broad host range of crops and ornamental plants, including potatoes. Previous research on animal pathogens, and a few plant pathogens, revealed that Outer Membrane Vesicles (OMVs) are part of Gram-negative bacteria's (GNB) adaptive toolkit. For this reason, OMV production and subsequent release from bacteria is a conserved process. Therefore, we hypothesized that OMVs might transport proteins that play a critical role in causing soft rot disease and in the survival and fitness of Pbr1692. Here, we show that the potato pathogen, Pbr1692, releases OMVs of various morphologies in Luria Bertani media at 31 °C. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) confirmed the production of OMVs by Pbr1692 cells. Transmission Electron Microscopy showed that these exist as chain-, single-, and double-membrane morphologies. Mass spectrometry followed by Gene Ontology, Clusters of Orthologous Groups, Virulence Factor, CAZymes, Antibiotic Resistance Ontology, and Bastion6 T6SE annotations identified 129 OMV-associated proteins with diverse annotated roles, including antibiotic stress response, virulence, and competition. Pbr1692 OMVs contributed to virulence in potato tubers and elicited a hypersensitive response in Nicotiana benthamiana leaves. Furthermore, Pbr1692 OMVs demonstrated antibacterial activity against Dickeya dadantii.
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Affiliation(s)
- Silindile Maphosa
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Lunnon Road, Pretoria 0028, South Africa;
- Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Lunnon Road, Pretoria 0028, South Africa
| | - Lucy Novungayo Moleleki
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Lunnon Road, Pretoria 0028, South Africa;
- Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Lunnon Road, Pretoria 0028, South Africa
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22
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Abrahamian P, Klein-Gordon JM, Jones JB, Vallad GE. Epidemiology, diversity, and management of bacterial spot of tomato caused by Xanthomonas perforans. Appl Microbiol Biotechnol 2021; 105:6143-6158. [PMID: 34342710 DOI: 10.1007/s00253-021-11459-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 07/05/2021] [Accepted: 07/09/2021] [Indexed: 11/28/2022]
Abstract
Tomato is an important crop grown worldwide. Various plant diseases cause massive losses in tomato plants due to diverse biotic agents. Bacterial spot of tomato (BST) is a worldwide disease that results in high losses in processed and fresh tomato. Xanthomonas perforans, an aerobic, single-flagellated, rod-shaped, Gram-negative plant pathogenic bacterium, is one of the leading causes of BST. Over the past three decades, X. perforans has increasingly been reported from tomato-growing regions and became a major bacterial disease. X. perforans thrives under high humidity and high temperature, which is commonplace in tropical and subtropical climates. Distinguishing symptoms of BST are necrotic lesions that can coalesce and cause a shot-hole appearance. X. perforans can occasionally cause fruit symptoms depending on disease pressure during fruit development. Short-distance movement in the field is mainly dependent on wind-driven rain, whereas long distance movement occurs through contaminated seed or plant material. X. perforans harbors a suite of effectors that increase pathogen virulence, fitness, and dissemination. BST management mainly relies on copper-based compounds; however, resistance is widespread. Alternative compounds, such as nanomaterials, are currently being evaluated and show high potential for BST management. Resistance breeding remains difficult to attain due to limited resistant germplasm. While the increased genetic diversity and gain and loss of effectors in X. perforans limits the success of single-gene resistance, the adoption of effector-specific transgenes and quantitative resistance may lead to durable host resistance. However, further research that aims to more effectively implement novel management tools is required to curb disease spread. KEY POINTS: • Xanthomonas perforans causes bacterial spot on tomato epidemics through infected seedlings and movement of plant material. • Genetic diversity plays a major role in shaping populations which is evident in loss and gain of effectors. • Management relies on copper sprays, but nanoparticles are a promising alternative to reduce copper toxicity.
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Affiliation(s)
- Peter Abrahamian
- Beltsville Agricultural Research Center, Molecular Plant Pathology Laboratory, USDA-ARS, Beltsville, MD, 20705, USA.
| | | | - Jeffrey B Jones
- Department of Plant Pathology, University of Florida, Gainesville, FL, 32611, USA
| | - Gary E Vallad
- Gulf Coast Research and Education Center, University of Florida, Wimauma, FL, 33598, USA.
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O’Malley MR, Anderson JC. Regulation of the Pseudomonas syringae Type III Secretion System by Host Environment Signals. Microorganisms 2021; 9:microorganisms9061227. [PMID: 34198761 PMCID: PMC8228185 DOI: 10.3390/microorganisms9061227] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/30/2021] [Accepted: 06/01/2021] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas syringae are Gram-negative, plant pathogenic bacteria that use a type III secretion system (T3SS) to disarm host immune responses and promote bacterial growth within plant tissues. Despite the critical role for type III secretion in promoting virulence, T3SS-encoding genes are not constitutively expressed by P. syringae and must instead be induced during infection. While it has been known for many years that culturing P. syringae in synthetic minimal media can induce the T3SS, relatively little is known about host signals that regulate the deployment of the T3SS during infection. The recent identification of specific plant-derived amino acids and organic acids that induce T3SS-inducing genes in P. syringae has provided new insights into host sensing mechanisms. This review summarizes current knowledge of the regulatory machinery governing T3SS deployment in P. syringae, including master regulators HrpRS and HrpL encoded within the T3SS pathogenicity island, and the environmental factors that modulate the abundance and/or activity of these key regulators. We highlight putative receptors and regulatory networks involved in linking the perception of host signals to the regulation of the core HrpRS–HrpL pathway. Positive and negative regulation of T3SS deployment is also discussed within the context of P. syringae infection, where contributions from distinct host signals and regulatory networks likely enable the fine-tuning of T3SS deployment within host tissues. Last, we propose future research directions necessary to construct a comprehensive model that (a) links the perception of host metabolite signals to T3SS deployment and (b) places these host–pathogen signaling events in the overall context of P. syringae infection.
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Stice SP, Shin GY, De Armas S, Koirala S, Galván GA, Siri MI, Severns PM, Coutinho T, Dutta B, Kvitko BH. The Distribution of Onion Virulence Gene Clusters Among Pantoea spp. FRONTIERS IN PLANT SCIENCE 2021; 12:643787. [PMID: 33777079 PMCID: PMC7988079 DOI: 10.3389/fpls.2021.643787] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/18/2021] [Indexed: 05/31/2023]
Abstract
Pantoea ananatis is a gram-negative bacterium and the primary causal agent of center rot of onions in Georgia. Previous genomic studies identified two virulence gene clusters, HiVir and alt, associated with center rot. The HiVir gene cluster is required to induce necrosis on onion tissues via synthesis of pantaphos, (2-hydroxy[phosphono-methyl)maleate), a phosphonate phytotoxin. The alt gene cluster aids in tolerance to thiosulfinates generated during onion tissue damage. Whole genome sequencing of other Pantoea species suggests that these gene clusters are present outside of P. ananatis. To assess the distribution of these gene clusters, two PCR primer sets were designed to detect the presence of HiVir and alt. Two hundred fifty-two strains of Pantoea spp. were phenotyped using the red onion scale necrosis (RSN) assay and were genotyped using PCR for the presence of these virulence genes. A diverse panel of strains from three distinct culture collections comprised of 24 Pantoea species, 41 isolation sources, and 23 countries, collected from 1946-2019, was tested. There is a significant association between the alt PCR assay and Pantoea strains recovered from symptomatic onion (P < 0.001). There is also a significant association of a positive HiVir PCR and RSN assay among P. ananatis strains but not among Pantoea spp., congeners. This may indicate a divergent HiVir cluster or different pathogenicity and virulence mechanisms. Last, we describe natural alt positive [RSN+/HiVir+/alt +] P. ananatis strains, which cause extensive bulb necrosis in a neck-to-bulb infection assay compared to alt negative [RSN+/HiVir+/alt -] P. ananatis strains. A combination of assays that include PCR of virulence genes [HiVir and alt] and an RSN assay can potentially aid in identification of onion-bulb-rotting pathogenic P. ananatis strains.
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Affiliation(s)
- Shaun P. Stice
- Department of Plant Pathology, University of Georgia College of Agricultural and Environmental Sciences, Athens, GA, United States
| | - Gi Yoon Shin
- Centre for Microbial Ecology and Genomics, Forestry and Agriculture Biotechnology Institute, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Stefanie De Armas
- Área de Microbiología, Departamento de Biociencias, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Santosh Koirala
- Department of Plant Pathology, University of Georgia College of Agricultural and Environmental Sciences, Athens, GA, United States
| | - Guillermo A. Galván
- Departamento de Producción Vegetal, Centro Regional Sur (CRS), Facultad de Agronomía, Universidad de la República, Canelones, Uruguay
| | - María Inés Siri
- Área de Microbiología, Departamento de Biociencias, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Paul M. Severns
- Department of Plant Pathology, University of Georgia College of Agricultural and Environmental Sciences, Athens, GA, United States
| | - Teresa Coutinho
- Centre for Microbial Ecology and Genomics, Forestry and Agriculture Biotechnology Institute, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Bhabesh Dutta
- Department of Plant Pathology, University of Georgia College of Agricultural and Environmental Sciences, Athens, GA, United States
| | - Brian H. Kvitko
- Department of Plant Pathology, University of Georgia College of Agricultural and Environmental Sciences, Athens, GA, United States
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O'Leary ML, Gilbertson RL. Complete Genome Sequence Resource of a Strain of Curtobacterium flaccumfaciens pv. flaccumfaciens, the Causal Agent of Bacterial Wilt of Common Bean, from Turkey. PHYTOPATHOLOGY 2020; 110:2010-2013. [PMID: 32613911 DOI: 10.1094/phyto-04-20-0131-a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Curtobacterium flaccumfaciens pv. flaccumfaciens is the causal agent of bacterial wilt of common bean (Phaseolus vulgaris), a disease that can reduce yields of this economically important crop worldwide. Current genomics resources for this bacterial pathogen are limited. Therefore, long-read sequencing was used to determine the complete genome sequence of a pathogenic C. flaccumfaciens pv. flaccumfaciens strain isolated from common bean leaves showing irregular necrotic lesions with yellow borders collected in a commercial field in Turkey in 2015.
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Affiliation(s)
- Michael L O'Leary
- Department of Plant Pathology, University of California, Davis, One Shields Ave., Davis, CA 95616
| | - Robert L Gilbertson
- Department of Plant Pathology, University of California, Davis, One Shields Ave., Davis, CA 95616
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26
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Yan Q, Rogan CJ, Pang YY, Davis EW, Anderson JC. Ancient co-option of an amino acid ABC transporter locus in Pseudomonas syringae for host signal-dependent virulence gene regulation. PLoS Pathog 2020; 16:e1008680. [PMID: 32673374 PMCID: PMC7386598 DOI: 10.1371/journal.ppat.1008680] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 07/28/2020] [Accepted: 06/03/2020] [Indexed: 01/09/2023] Open
Abstract
Pathogenic bacteria frequently acquire virulence traits via horizontal gene transfer, yet additional evolutionary innovations may be necessary to integrate newly acquired genes into existing regulatory pathways. The plant bacterial pathogen Pseudomonas syringae relies on a horizontally acquired type III secretion system (T3SS) to cause disease. T3SS-encoding genes are induced by plant-derived metabolites, yet how this regulation occurs, and how it evolved, is poorly understood. Here we report that the two-component system AauS-AauR and substrate-binding protein AatJ, proteins encoded by an acidic amino acid-transport (aat) and -utilization (aau) locus in P. syringae, directly regulate T3SS-encoding genes in response to host aspartate and glutamate signals. Mutants of P. syringae strain DC3000 lacking aauS, aauR or aatJ expressed lower levels of T3SS genes in response to aspartate and glutamate, and had decreased T3SS deployment and virulence during infection of Arabidopsis. We identified an AauR-binding motif (Rbm) upstream of genes encoding T3SS regulators HrpR and HrpS, and demonstrated that this Rbm is required for maximal T3SS deployment and virulence of DC3000. The Rbm upstream of hrpRS is conserved in all P. syringae strains with a canonical T3SS, suggesting AauR regulation of hrpRS is ancient. Consistent with a model of conserved function, an aauR deletion mutant of P. syringae strain B728a, a bean pathogen, had decreased T3SS expression and growth in host plants. Together, our data suggest that, upon acquisition of T3SS-encoding genes, a strain ancestral to P. syringae co-opted an existing AatJ-AauS-AauR pathway to regulate T3SS deployment in response to specific host metabolite signals.
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Affiliation(s)
- Qing Yan
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Conner J. Rogan
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Yin-Yuin Pang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Edward W. Davis
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, Oregon, United States of America
| | - Jeffrey C. Anderson
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
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27
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Lomovatskaya LA, Romanenko AS. Secretion Systems of Bacterial Phytopathogens and Mutualists (Review). APPL BIOCHEM MICRO+ 2020. [DOI: 10.1134/s0003683820020106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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28
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Sen R, Tagore S, De RK. Cluster Quality based Non-Reductional (CQNR) oversampling technique and effector protein predictor based on 3D structure (EPP3D) of proteins. Comput Biol Med 2019; 112:103374. [DOI: 10.1016/j.compbiomed.2019.103374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 07/26/2019] [Accepted: 07/26/2019] [Indexed: 11/28/2022]
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29
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Thapa SP, Davis EW, Lyu Q, Weisberg AJ, Stevens DM, Clarke CR, Coaker G, Chang JH. The Evolution, Ecology, and Mechanisms of Infection by Gram-Positive, Plant-Associated Bacteria. ANNUAL REVIEW OF PHYTOPATHOLOGY 2019; 57:341-365. [PMID: 31283433 DOI: 10.1146/annurev-phyto-082718-100124] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Gram-positive bacteria are prominent members of plant-associated microbial communities. Although many are hypothesized to be beneficial, some are causative agents of economically important diseases of crop plants. Because the features of Gram-positive bacteria are fundamentally different relative to those of Gram-negative bacteria, the evolution and ecology as well as the mechanisms used to colonize and infect plants also differ. Here, we discuss recent advances in our understanding of Gram-positive, plant-associated bacteria and provide a framework for future research directions on these important plant symbionts.
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Affiliation(s)
- Shree P Thapa
- Department of Plant Pathology, University of California, Davis, California 95616, USA
| | - Edward W Davis
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331, USA;
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, Oregon 97331, USA
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, Oregon 97331, USA
| | - Qingyang Lyu
- Department of Plant Pathology, University of California, Davis, California 95616, USA
| | - Alexandra J Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331, USA;
| | - Danielle M Stevens
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331, USA;
- Integrative Genetics and Genomics, University of California, Davis, California 95616, USA
| | - Christopher R Clarke
- Genetic Improvement for Fruits and Vegetables Laboratory, Agricultural Research Service, US Department of Agriculture, Beltsville, Maryland 20705, USA
| | - Gitta Coaker
- Department of Plant Pathology, University of California, Davis, California 95616, USA
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331, USA;
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, Oregon 97331, USA
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, Oregon 97331, USA
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30
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Wu CF, Santos MNM, Cho ST, Chang HH, Tsai YM, Smith DA, Kuo CH, Chang JH, Lai EM. Plant-Pathogenic Agrobacterium tumefaciens Strains Have Diverse Type VI Effector-Immunity Pairs and Vary in In-Planta Competitiveness. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:961-971. [PMID: 30830835 DOI: 10.1094/mpmi-01-19-0021-r] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The type VI secretion system (T6SS) is used by gram-negative bacteria to translocate effectors that can antagonize other bacterial cells. Models predict the variation in collections of effector and cognate immunity genes determine competitiveness and can affect the dynamics of populations and communities of bacteria. However, the outcomes of competition cannot be entirely explained by compatibility of effector-immunity (EI) pairs. Here, we characterized the diversity of T6SS loci of plant-pathogenic Agrobacterium tumefaciens and showed that factors other than EI pairs can impact interbacterial competition. All examined strains encode T6SS active in secretion and antagonism against Escherichia coli. The spectra of EI pairs as well as compositions of gene neighborhoods are diverse. Almost 30 in-planta competitions were tested between different genotypes of A. tumefaciens. Fifteen competitions between members of different species-level groups resulted in T6SS-dependent suppression in in-planta growth of prey genotypes. In contrast, ten competitions between members within species-level groups resulted in no significant effect on the growth of prey genotypes. One strain was an exceptional case and, despite encoding a functional T6SS and toxic effector protein, could not compromise the growth of the four tested prey genotypes. The data suggest T6SS-associated EI pairs can influence the competitiveness of strains of A. tumefaciens, but genetic features have a significant role on the efficacy of interbacterial antagonism.
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Affiliation(s)
- Chih-Feng Wu
- 1Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
- 2Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, U.S.A
| | - Mary Nia M Santos
- 1Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Shu-Ting Cho
- 1Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Hsing-Hua Chang
- 1Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Yi-Ming Tsai
- 1Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Delaney A Smith
- 2Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, U.S.A
| | - Chih-Horng Kuo
- 1Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Jeff H Chang
- 2Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, U.S.A
- 3Center for Genome Research and Biocomputing, Oregon State University
| | - Erh-Min Lai
- 1Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
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31
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Zeng C, Zou L. An account of in silico identification tools of secreted effector proteins in bacteria and future challenges. Brief Bioinform 2019; 20:110-129. [PMID: 28981574 DOI: 10.1093/bib/bbx078] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Indexed: 01/08/2023] Open
Abstract
Bacterial pathogens secrete numerous effector proteins via six secretion systems, type I to type VI secretion systems, to adapt to new environments or to promote virulence by bacterium-host interactions. Many computational approaches have been used in the identification of effector proteins before the subsequent experimental verification because they tolerate laborious biological procedures and are genome scale, automated and highly efficient. Prevalent examples include machine learning methods and statistical techniques. In this article, we summarize the computational progress toward predicting secreted effector proteins in bacteria, with an opening of an introduction of features that are used to discriminate effectors from non-effectors. The mechanism, contribution and deficiency of previous developed detection tools are presented, which are further benchmarked based on a curated testing data set. According to the results of benchmarking, potential improvements of the prediction performance are discussed, which include (1) more informative features for discriminating the effectors from non-effectors; (2) the construction of comprehensive training data set of the machine learning algorithms; (3) the advancement of reliable prediction methods and (4) a better interpretation of the mechanisms behind the molecular processes. The future of in silico identification of bacterial secreted effectors includes both opportunities and challenges.
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Affiliation(s)
- Cong Zeng
- Bioinformatics Center, Third Military Medical University (TMMU), China
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32
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Castillo JA, Agathos SN. A genome-wide scan for genes under balancing selection in the plant pathogen Ralstonia solanacearum. BMC Evol Biol 2019; 19:123. [PMID: 31208326 PMCID: PMC6580516 DOI: 10.1186/s12862-019-1456-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 06/10/2019] [Indexed: 02/07/2023] Open
Abstract
Background Plant pathogens are under significant selective pressure by the plant host. Consequently, they are expected to have adapted to this condition or contribute to evading plant defenses. In order to acquire long-term fitness, plant bacterial pathogens are usually forced to maintain advantageous genetic diversity in populations. This strategy ensures that different alleles in the pathogen’s gene pool are maintained in a population at frequencies larger than expected under neutral evolution. This selective process, known as balancing selection, is the subject of this work in the context of a common bacterial phytopathogen. We performed a genome-wide scan of Ralstonia solanacearum species complex, an aggressive plant bacterial pathogen that shows broad host range and causes a devastating disease called ‘bacterial wilt’. Results Using a sliding window approach, we analyzed 57 genomes from three phylotypes of the R. solanacearum species complex to detect signatures of balancing selection. A total of 161 windows showed extreme values in three summary statistics of population genetics: Tajima’s D, θw and Fu & Li’s D*. We discarded any confounding effects due to demographic events by means of coalescent simulations of genetic data. The prospective windows correspond to 78 genes with known function that map in any of the two main replicons (1.7% of total number of genes). The candidate genes under balancing selection are related to primary metabolism and other basal activities (51.3%) or directly associated to virulence (48.7%), the latter being involved in key functions targeted to dismantle plant defenses or to participate in critical stages in the pathogenic process. Conclusions We identified various genes under balancing selection that play a significant role in basic metabolism as well as in virulence of the R. solanacearum species complex. These genes are useful to understand and monitor the evolution of bacterial pathogen populations and emerge as potential candidates for future treatments to induce specific plant immune responses. Electronic supplementary material The online version of this article (10.1186/s12862-019-1456-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- José A Castillo
- School of Biological Sciences and Engineering, Yachay Tech University, Hacienda San Jose s/n and Proyecto Yachay, Urcuquí, Ecuador.
| | - Spiros N Agathos
- School of Biological Sciences and Engineering, Yachay Tech University, Hacienda San Jose s/n and Proyecto Yachay, Urcuquí, Ecuador
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Li L, Yuan L, Shi Y, Xie X, Chai A, Wang Q, Li B. Comparative genomic analysis of Pectobacterium carotovorum subsp. brasiliense SX309 provides novel insights into its genetic and phenotypic features. BMC Genomics 2019; 20:486. [PMID: 31195968 PMCID: PMC6567464 DOI: 10.1186/s12864-019-5831-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 05/23/2019] [Indexed: 12/20/2022] Open
Abstract
Background Pectobacterium carotovorum subsp. brasiliense is a broad host range bacterial pathogen, which causes blackleg of potatoes and bacterial soft rot of vegetables worldwide. Production of plant cell wall degrading enzymes is usually critical for Pectobacterium infection. However, other virulence factors and the mechanisms of genetic adaptation still need to be studied in detail. Results In this study, the complete genome of P. carotovorum subsp. brasiliense strain SX309 isolated from cucumber was compared with eight other pathogenic bacteria belonging to the Pectobacterium genus, which were isolated from various host plants. Genome comparison revealed that most virulence genes are highly conserved in the Pectobacterium strains, especially for the key virulence determinants involved in the biosynthesis of extracellular enzymes and others including the type II and III secretion systems, quorum sensing system, flagellar and chemotactic genes. Nevertheless, some variable regions of the T6SS and the CRISP-Cas immune system are unique for P. carotovorum subsp. brasiliense. Conclusions The extensive comparative genomics analysis revealed highly conserved virulence genes in the Pectobacterium strains. However, several variable regions of type VI secretion system and two subtype Cas mechanism-Cas immune systems possibly contribute to the process of Pectobacterium infection and adaptive immunity. Electronic supplementary material The online version of this article (10.1186/s12864-019-5831-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lei Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Lifang Yuan
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.,Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, 100193, China
| | - Yanxia Shi
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Xuewen Xie
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Ali Chai
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Qi Wang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, 100193, China
| | - Baoju Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
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Li Y, Liu J, Díaz-Cruz G, Cheng Z, Bignell DRD. Virulence mechanisms of plant-pathogenic Streptomyces species: an updated review. MICROBIOLOGY-SGM 2019; 165:1025-1040. [PMID: 31162023 DOI: 10.1099/mic.0.000818] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Gram-positive Actinobacteria from the genus Streptomyces are best known for their morphological complexity and for their ability to produce numerous bioactive specialized metabolites with useful applications in human and veterinary medicine and in agriculture. In contrast, the ability to infect living plant tissues and to cause diseases of root and tuber crops such as potato common scab (CS) is a rare attribute among members of this genus. Research on the virulence mechanisms of plant-pathogenic Streptomyces spp. has revealed the importance of the thaxtomin phytotoxins as key pathogenicity determinants produced by several species. In addition, other phytotoxic specialized metabolites may contribute to the development or severity of disease caused by Streptomyces spp., along with the production of phytohormones and secreted proteins. A thorough understanding of the molecular mechanisms of plant pathogenicity will enable the development of better management procedures for controlling CS and other plant diseases caused by the Streptomyces.
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Affiliation(s)
- Yuting Li
- Department of Biology, Memorial University of Newfoundland, St John's, NL A1B 3X9, Canada
| | - Jingyu Liu
- Department of Biology, Memorial University of Newfoundland, St John's, NL A1B 3X9, Canada
| | - Gustavo Díaz-Cruz
- Department of Biology, Memorial University of Newfoundland, St John's, NL A1B 3X9, Canada
| | - Zhenlong Cheng
- Department of Biology, Memorial University of Newfoundland, St John's, NL A1B 3X9, Canada
| | - Dawn R D Bignell
- Department of Biology, Memorial University of Newfoundland, St John's, NL A1B 3X9, Canada
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Li X, Ma Y, Liang S, Tian Y, Yin S, Xie S, Xie H. Comparative genomics of 84 Pectobacterium genomes reveals the variations related to a pathogenic lifestyle. BMC Genomics 2018; 19:889. [PMID: 30526490 PMCID: PMC6286560 DOI: 10.1186/s12864-018-5269-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/19/2018] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Pectobacterium spp. are necrotrophic bacterial plant pathogens of the family Pectobacteriaceae, responsible for a wide spectrum of diseases of important crops and ornamental plants including soft rot, blackleg, and stem wilt. P. carotovorum is a genetically heterogeneous species consisting of three valid subspecies, P. carotovorum subsp. brasiliense (Pcb), P. carotovorum subsp. carotovorum (Pcc), and P. carotovorum subsp. odoriferum (Pco). RESULTS Thirty-two P. carotovorum strains had their whole genomes sequenced, including the first complete genome of Pco and another circular genome of Pcb, as well as the high-coverage genome sequences for 30 additional strains covering Pcc, Pcb, and Pco. In combination with 52 other publicly available genome sequences, the comparative genomics study of P. carotovorum and other four closely related species P. polaris, P. parmentieri, P. atrosepticum, and Candidatus P. maceratum was conducted focusing on CRISPR-Cas defense systems and pathogenicity determinants. Our analysis identified two CRISPR-Cas types (I-F and I-E) in Pectobacterium, as well as another I-C type in Dickeya that is not found in Pectobacterium. The core pathogenicity factors (e.g., plant cell wall-degrading enzymes) were highly conserved, whereas some factors (e.g., flagellin, siderophores, polysaccharides, protein secretion systems, and regulatory factors) were varied among these species and/or subspecies. Notably, a novel type of T6SS as well as the sorbitol metabolizing srl operon was identified to be specific to Pco in Pectobacterium. CONCLUSIONS This study not only advances the available knowledge about the genetic differentiation of individual subspecies of P. carotovorum, but also delineates the general genetic features of P. carotovorum by comparison with its four closely related species, thereby substantially enriching the extent of information now available for functional genomic investigations about Pectobacterium.
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Affiliation(s)
- Xiaoying Li
- Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097 People’s Republic of China
- Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing, 100097 People’s Republic of China
| | - Yali Ma
- Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097 People’s Republic of China
- Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing, 100097 People’s Republic of China
| | - Shuqing Liang
- Health Time Gene Institute, Shenzhen, Guangdong 518000 People’s Republic of China
| | - Yu Tian
- Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097 People’s Republic of China
- Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing, 100097 People’s Republic of China
| | - Sanjun Yin
- Health Time Gene Institute, Shenzhen, Guangdong 518000 People’s Republic of China
| | - Sisi Xie
- Health Time Gene Institute, Shenzhen, Guangdong 518000 People’s Republic of China
| | - Hua Xie
- Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097 People’s Republic of China
- Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing, 100097 People’s Republic of China
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Schultz LG, Tasic L, Fattori J. Chaperone-Assisted Secretion in Bacteria: Protein and DNA Transport via Cell Membranes. CURR PROTEOMICS 2018. [DOI: 10.2174/1570164615666180820154821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Bacteria use an impressive arsenal of secretion systems (1-7) to infect their host cells by exporting
proteins, DNA and DNA-protein complexes via cell membranes. They use chaperone-usher
pathways for host colonization as well. To be targeted for transportation across one (Gram-positive) or
two membranes (Gram-negative), clients must be selected, guided and unfolded to pass through type 3
(T3SS) or type 4 (T4SS) secretion systems. For these processes, bacteria count on secretory chaperones
that guide macromolecular transport via membranes. Moreover, if we know how these processes
occur, we might be able to stop them and avoid bacterial infections. Thus, structural and functional
characterizations of secretory chaperones become interesting, as these proteins are the perfect targets
for blocking bacteria action. Therefore, this review focuses on a story of known mechanisms of chaperone-
secretion assisted transport with special attention on virulence proteins and DNA transport in
bacteria.
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Affiliation(s)
- Lilian Goulart Schultz
- Chemical Biology Laboratory, Organic Chemistry Department, Institute of Chemistry, University of Campinas, P.O. Box 6154, Campinas, 13083-970, SP, Brazil
| | - Ljubica Tasic
- Chemical Biology Laboratory, Organic Chemistry Department, Institute of Chemistry, University of Campinas, P.O. Box 6154, Campinas, 13083-970, SP, Brazil
| | - Juliana Fattori
- Chemical Biology Laboratory, Organic Chemistry Department, Institute of Chemistry, University of Campinas, P.O. Box 6154, Campinas, 13083-970, SP, Brazil
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An Y, Wang J, Li C, Leier A, Marquez-Lago T, Wilksch J, Zhang Y, Webb GI, Song J, Lithgow T. Comprehensive assessment and performance improvement of effector protein predictors for bacterial secretion systems III, IV and VI. Brief Bioinform 2018; 19:148-161. [PMID: 27777222 DOI: 10.1093/bib/bbw100] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Indexed: 11/15/2022] Open
Abstract
Bacterial effector proteins secreted by various protein secretion systems play crucial roles in host-pathogen interactions. In this context, computational tools capable of accurately predicting effector proteins of the various types of bacterial secretion systems are highly desirable. Existing computational approaches use different machine learning (ML) techniques and heterogeneous features derived from protein sequences and/or structural information. These predictors differ not only in terms of the used ML methods but also with respect to the used curated data sets, the features selection and their prediction performance. Here, we provide a comprehensive survey and benchmarking of currently available tools for the prediction of effector proteins of bacterial types III, IV and VI secretion systems (T3SS, T4SS and T6SS, respectively). We review core algorithms, feature selection techniques, tool availability and applicability and evaluate the prediction performance based on carefully curated independent test data sets. In an effort to improve predictive performance, we constructed three ensemble models based on ML algorithms by integrating the output of all individual predictors reviewed. Our benchmarks demonstrate that these ensemble models outperform all the reviewed tools for the prediction of effector proteins of T3SS and T4SS. The webserver of the proposed ensemble methods for T3SS and T4SS effector protein prediction is freely available at http://tbooster.erc.monash.edu/index.jsp. We anticipate that this survey will serve as a useful guide for interested users and that the new ensemble predictors will stimulate research into host-pathogen relationships and inspiration for the development of new bioinformatics tools for predicting effector proteins of T3SS, T4SS and T6SS.
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Li L, Yuan L, Shi Y, Xie X, Chai A, Wang Q, Li B. Comparative genomic analysis of Pseudomonas amygdali pv. lachrymans NM002: Insights into its potential virulence genes and putative invasion determinants. Genomics 2018; 111:1493-1503. [PMID: 30336277 DOI: 10.1016/j.ygeno.2018.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 09/30/2018] [Accepted: 10/04/2018] [Indexed: 12/01/2022]
Abstract
Pseudomonas amygdali pv. lachrymans is currently of important plant pathogenic bacteria that causes cucumber angular leaf spot worldwide. The pathogen has been studied for its roles in pathogenicity and plant inheritance resistance. To further delineate traits critical to virulence, invasion and survival in the phyllosphere, we reported the first complete genome of P. amygdali pv. lachrymans NM002. Analysis of the whole genome in comparison with three closely-related representative pathovars of P. syringae identified the conservation of virulence genes, including flagella and chemotaxis, quorum-sensing systems, two-component systems, and lipopolysaccharide and antiphagocytosis. It also revealed differences of invasion determinants, such as type III effectors, phytotoxin (coronatine, syringomycin and phaseolotoxin) and cell wall-degrading enzyme, which may contribute to infectivity. The aim of this study was to derive genomic information that would reveal the probable molecular mechanisms underlying the virulence, infectivity and provide a better understanding of the pathogenesis of the P. syringae pathovars.
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Affiliation(s)
- Lei Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Lifang Yuan
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Yanxia Shi
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xuewen Xie
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Ali Chai
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Qi Wang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Baoju Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
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Rüter C, Lubos ML, Norkowski S, Schmidt MA. All in—Multiple parallel strategies for intracellular delivery by bacterial pathogens. Int J Med Microbiol 2018; 308:872-881. [DOI: 10.1016/j.ijmm.2018.06.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 06/01/2018] [Accepted: 06/16/2018] [Indexed: 02/06/2023] Open
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Carella P, Evangelisti E, Schornack S. Sticking to it: phytopathogen effector molecules may converge on evolutionarily conserved host targets in green plants. CURRENT OPINION IN PLANT BIOLOGY 2018; 44:175-180. [PMID: 30071474 PMCID: PMC6119762 DOI: 10.1016/j.pbi.2018.04.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/06/2018] [Accepted: 04/28/2018] [Indexed: 05/26/2023]
Abstract
•Phytopathogen effectors converge on similar sets of host proteins in angiosperms. •Effectors may target host proteins and processes present across the green plant lineage. •Bryophyte model plants are promising systems to investigate effector–target relationships. Plant-associated microbes secrete effector proteins that subvert host cellular machinery to facilitate the colonization of plant tissues and cells. Accumulating data suggests that independently evolved effectors from bacterial, fungal, and oomycete pathogens may converge on a similar set of host proteins in certain angiosperm models, however, whether this concept is relevant throughout the green plant lineage is unknown. Here, we explore the idea that pathogen effector molecules target host proteins present across evolutionarily distant land plant lineages to promote disease. We discuss that host proteins targeted by phytopathogens or integrated into angiosperm immune receptors are likely found across green plant genomes, from early diverging non-vascular lineages (bryophytes) to flowering plants (angiosperms). This would suggest that independently evolved pathogens might manipulate their hosts by targeting `vulnerability’ hubs that are present across land plants. Future work focusing on accessible early divergent land plant model systems may therefore provide an insightful evolutionary backdrop for effector–target research.
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Affiliation(s)
- Philip Carella
- University of Cambridge, Sainsbury Laboratory, Cambridge, United Kingdom
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Gambetta GA, Matthews MA, Syvanen M. The Xylella fastidosa RTX operons: evidence for the evolution of protein mosaics through novel genetic exchanges. BMC Genomics 2018; 19:329. [PMID: 29728072 PMCID: PMC5935956 DOI: 10.1186/s12864-018-4731-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 04/26/2018] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Xylella fastidiosa (Xf) is a gram negative bacterium inhabiting the plant vascular system. In most species this bacterium lives as a benign symbiote, but in several agriculturally important plants (e.g. coffee, citrus, grapevine) Xf is pathogenic. Xf has four loci encoding homologues to hemolysin RTX proteins, virulence factors involved in a wide range of plant pathogen interactions. RESULTS We show that all four genes are expressed during pathogenesis in grapevine. The sequences from these four genes have a complex repetitive structure. At the C-termini, sequence diversity between strains is what would be expected from orthologous genes. However, within strains there is no N-terminal homology, indicating these loci encode RTXs of different functions and/or specificities. More striking is that many of the orthologous loci between strains share this extreme variation at the N-termini. Thus these RTX orthologues are most easily visualized as fusions between the orthologous C-termini and different N-termini. Further, the four genes are found in operons having a peculiar structure with an extensively duplicated module encoding a small protein with homology to the N-terminal region of the full length RTX. Surprisingly, some of these small peptides are most similar not to their corresponding full length RTX, but to the N-termini of RTXs from other Xf strains, and even other remotely related species. CONCLUSIONS These results demonstrate that these genes are expressed in planta during pathogenesis. Their structure suggests extensive evolutionary restructuring through horizontal gene transfers and heterologous recombination mechanisms. The sum of the evidence suggests these repetitive modules are a novel kind of mobile genetic element.
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Affiliation(s)
- Gregory A Gambetta
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, UMR 1287, F- 33140, Villenave d'Ornon, France.
| | - Mark A Matthews
- Department of Viticulture and Enology, University of California, Davis, CA, 95616-8645, USA
| | - Michael Syvanen
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, CA, 95616-8645, USA
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42
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Deb D, Anderson RG, How-Yew-Kin T, Tyler BM, McDowell JM. Conserved RxLR Effectors From Oomycetes Hyaloperonospora arabidopsidis and Phytophthora sojae Suppress PAMP- and Effector-Triggered Immunity in Diverse Plants. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:374-385. [PMID: 29106332 DOI: 10.1094/mpmi-07-17-0169-fi] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Effector proteins are exported to the interior of host cells by diverse plant pathogens. Many oomycete pathogens maintain large families of candidate effector genes, encoding proteins with a secretory leader followed by an RxLR motif. Although most of these genes are very divergent between oomycete species, several genes are conserved between Phytophthora species and Hyaloperonospora arabidopsidis, suggesting that they play important roles in pathogenicity. We describe a pair of conserved effector candidates, HaRxL23 and PsAvh73, from H. arabidopsidis and P. sojae respectively. We show that HaRxL23 is expressed early during infection of Arabidopsis. HaRxL23 triggers an ecotype-specific defense response in Arabidopsis, suggesting that it is recognized by a host surveillance protein. HaRxL23 and PsAvh73 can suppress pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) in Nicotiana benthamiana and effector-triggered immunity (ETI) in soybean. Transgenic Arabidopsis constitutively expressing HaRxL23 or PsAvh73 exhibit suppression of PTI and enhancement of bacterial and oomycete virulence. Together, our experiments demonstrate that these conserved oomycete RxLR effectors suppress PTI and ETI across diverse plant species.
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Affiliation(s)
- Devdutta Deb
- 1 Department of Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, VA, 24061-0329, U.S.A
| | - Ryan G Anderson
- 1 Department of Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, VA, 24061-0329, U.S.A
| | - Theresa How-Yew-Kin
- 1 Department of Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, VA, 24061-0329, U.S.A
| | - Brett M Tyler
- 2 Center for Genome Research and Biocomputing, and Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, U.S.A
| | - John M McDowell
- 1 Department of Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, VA, 24061-0329, U.S.A
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43
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Wu CF, Smith DA, Lai EM, Chang JH. The Agrobacterium Type VI Secretion System: A Contractile Nanomachine for Interbacterial Competition. Curr Top Microbiol Immunol 2018; 418:215-231. [PMID: 29992360 DOI: 10.1007/82_2018_99] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The bacterial type VI secretion system (T6SS) is a contractile nanomachine dedicated to delivering molecules out of bacterial cells. T6SS-encoding loci are in the genome sequences of many Gram-negative bacteria, and T6SS has been implicated in a plethora of roles. In the majority of cases, the T6SSs deliver effector proteins in a contact-dependent manner to antagonize other bacteria. Current models suggest that the effectors are deployed to influence social interactions in microbial communities. In this chapter, we describe the structure, function, and regulation of the T6SS and its effectors. We provide focus on the T6SS of Agrobacterium tumefaciens, the causative agent of crown gall disease, and relate the role of the T6SS to the ecology of A. tumefaciens.
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Affiliation(s)
- Chih-Feng Wu
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA
| | - Delaney A Smith
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA
| | - Erh-Min Lai
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA.
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA.
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44
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Thapa SP, Pattathil S, Hahn MG, Jacques MA, Gilbertson RL, Coaker G. Genomic Analysis of Clavibacter michiganensis Reveals Insight Into Virulence Strategies and Genetic Diversity of a Gram-Positive Bacterial Pathogen. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:786-802. [PMID: 28677494 DOI: 10.1094/mpmi-06-17-0146-r] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Clavibacter michiganensis subsp. michiganensis is a gram-positive bacterial pathogen that proliferates in the xylem vessels of tomato, causing bacterial canker disease. In this study, we sequenced and assembled genomes of 11 C. michiganensis subsp. michiganensis strains isolated from infected tomato fields in California as well as five Clavibacter strains that colonize tomato endophytically but are not pathogenic in this host. The analysis of the C. michiganensis subsp. michiganensis genomes supported the monophyletic nature of this pathogen but revealed genetic diversity among strains, consistent with multiple introduction events. Two tomato endophytes that clustered phylogenetically with C. michiganensis strains capable of infecting wheat and pepper and were also able to cause disease in these plants. Plasmid profiles of the California strains were variable and supported the essential role of the pCM1-like plasmid and the CelA cellulase in virulence, whereas the absence of the pCM2-like plasmid in some pathogenic C. michiganensis subsp. michiganensis strains revealed it is not essential. A large number of secreted C. michiganensis subsp. michiganensis proteins were carbohydrate-active enzymes (CAZymes). Glycome profiling revealed that C. michiganensis subsp. michiganensis but not endophytic Clavibacter strains is able to extensively alter tomato cell-wall composition. Two secreted CAZymes found in all C. michiganensis subsp. michiganensis strains, CelA and PelA1, enhanced pathogenicity on tomato. Collectively, these results provide a deeper understanding of C. michiganensis subsp. michiganensis diversity and virulence strategies.
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Affiliation(s)
- Shree P Thapa
- 1 Department of Plant Pathology, University of California, Davis, California, U.S.A
| | - Sivakumar Pattathil
- 2 Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia, U.S.A.; and
| | - Michael G Hahn
- 2 Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia, U.S.A.; and
| | | | - Robert L Gilbertson
- 1 Department of Plant Pathology, University of California, Davis, California, U.S.A
| | - Gitta Coaker
- 1 Department of Plant Pathology, University of California, Davis, California, U.S.A
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45
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Chang JH, Tabima JF. A Covert Operation by a Plant Pathogen. Cell Host Microbe 2017; 20:413-415. [PMID: 27736639 DOI: 10.1016/j.chom.2016.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phytopathogens have mastered the ability to evade plant innate immunity. In this issue of Cell Host & Microbe, Zhou and colleagues (Li et al., 2016) uncover a strategy whereby a bacterial pathogen disables the plant immune system with such precision as to avoid triggering alarms that could potentially reveal its presence.
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Affiliation(s)
- Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA; Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR 97331, USA.
| | - Javier F Tabima
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
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46
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Patel HK, Ferrante P, Xianfa M, Javvadi SG, Subramoni S, Scortichini M, Venturi V. Identification of Loci of Pseudomonas syringae pv. actinidiae Involved in Lipolytic Activity and Their Role in Colonization of Kiwifruit Leaves. PHYTOPATHOLOGY 2017; 107:645-653. [PMID: 28112597 DOI: 10.1094/phyto-10-16-0360-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Bacterial canker disease caused by Pseudomonas syringae pv. actinidiae, an emerging pathogen of kiwifruit plants, has recently brought about major economic losses worldwide. Genetic studies on virulence functions of P. syringae pv. actinidiae have not yet been reported and there is little experimental data regarding bacterial genes involved in pathogenesis. In this study, we performed a genetic screen in order to identify transposon mutants altered in the lipolytic activity because it is known that mechanisms of regulation, production, and secretion of enzymes often play crucial roles in virulence of plant pathogens. We aimed to identify the set of secretion and global regulatory loci that control lipolytic activity and also play important roles in in planta fitness. Our screen for altered lipolytic activity phenotype identified a total of 58 Tn5 transposon mutants. Mapping all these Tn5 mutants revealed that the transposons were inserted in genes that play roles in cell division, chemotaxis, metabolism, movement, recombination, regulation, signal transduction, and transport as well as a few unknown functions. Several of these identified P. syringae pv. actinidiae Tn5 mutants, notably the functions affected in phosphomannomutase AlgC, lipid A biosynthesis acyltransferase, glutamate-cysteine ligase, and the type IV pilus protein PilI, were also found affected in in planta survival and/or growth in kiwifruit plants. The results of the genetic screen and identification of novel loci involved in in planta fitness of P. syringae pv. actinidiae are presented and discussed.
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Affiliation(s)
- Hitendra Kumar Patel
- First, third, fourth, fifth, and seventh authors: International Centre for Genetic Engineering and Biotechnology, Trieste, Italy; second and sixth authors: Research Centre for Fruit Crops, Agricultural Research Council, Roma, Italy; and sixth author: Research Unit for Fruit Trees, Council for Agricultural Research and Economics, Caserta, Italy
| | - Patrizia Ferrante
- First, third, fourth, fifth, and seventh authors: International Centre for Genetic Engineering and Biotechnology, Trieste, Italy; second and sixth authors: Research Centre for Fruit Crops, Agricultural Research Council, Roma, Italy; and sixth author: Research Unit for Fruit Trees, Council for Agricultural Research and Economics, Caserta, Italy
| | - Meng Xianfa
- First, third, fourth, fifth, and seventh authors: International Centre for Genetic Engineering and Biotechnology, Trieste, Italy; second and sixth authors: Research Centre for Fruit Crops, Agricultural Research Council, Roma, Italy; and sixth author: Research Unit for Fruit Trees, Council for Agricultural Research and Economics, Caserta, Italy
| | - Sree Gowrinadh Javvadi
- First, third, fourth, fifth, and seventh authors: International Centre for Genetic Engineering and Biotechnology, Trieste, Italy; second and sixth authors: Research Centre for Fruit Crops, Agricultural Research Council, Roma, Italy; and sixth author: Research Unit for Fruit Trees, Council for Agricultural Research and Economics, Caserta, Italy
| | - Sujatha Subramoni
- First, third, fourth, fifth, and seventh authors: International Centre for Genetic Engineering and Biotechnology, Trieste, Italy; second and sixth authors: Research Centre for Fruit Crops, Agricultural Research Council, Roma, Italy; and sixth author: Research Unit for Fruit Trees, Council for Agricultural Research and Economics, Caserta, Italy
| | - Marco Scortichini
- First, third, fourth, fifth, and seventh authors: International Centre for Genetic Engineering and Biotechnology, Trieste, Italy; second and sixth authors: Research Centre for Fruit Crops, Agricultural Research Council, Roma, Italy; and sixth author: Research Unit for Fruit Trees, Council for Agricultural Research and Economics, Caserta, Italy
| | - Vittorio Venturi
- First, third, fourth, fifth, and seventh authors: International Centre for Genetic Engineering and Biotechnology, Trieste, Italy; second and sixth authors: Research Centre for Fruit Crops, Agricultural Research Council, Roma, Italy; and sixth author: Research Unit for Fruit Trees, Council for Agricultural Research and Economics, Caserta, Italy
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Abstract
Type II secretion (T2S) is one means by which Gram-negative pathogens secrete proteins into the extracellular milieu and/or host organisms. Based upon recent genome sequencing, it is clear that T2S is largely restricted to the Proteobacteria, occurring in many, but not all, genera in the Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria classes. Prominent human and/or animal pathogens that express a T2S system(s) include Acinetobacter baumannii, Burkholderia pseudomallei, Chlamydia trachomatis, Escherichia coli, Klebsiella pneumoniae, Legionella pneumophila, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Vibrio cholerae, and Yersinia enterocolitica T2S-expressing plant pathogens include Dickeya dadantii, Erwinia amylovora, Pectobacterium carotovorum, Ralstonia solanacearum, Xanthomonas campestris, Xanthomonas oryzae, and Xylella fastidiosa T2S also occurs in nonpathogenic bacteria, facilitating symbioses, among other things. The output of a T2S system can range from only one to dozens of secreted proteins, encompassing a diverse array of toxins, degradative enzymes, and other effectors, including novel proteins. Pathogenic processes mediated by T2S include the death of host cells, degradation of tissue, suppression of innate immunity, adherence to host surfaces, biofilm formation, invasion into and growth within host cells, nutrient assimilation, and alterations in host ion flux. The reach of T2S is perhaps best illustrated by those bacteria that clearly use it for both environmental survival and virulence; e.g., L. pneumophila employs T2S for infection of amoebae, growth within lung cells, dampening of cytokines, and tissue destruction. This minireview provides an update on the types of bacteria that have T2S, the kinds of proteins that are secreted via T2S, and how T2S substrates promote infection.
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48
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A Pseudomonas T6SS effector recruits PQS-containing outer membrane vesicles for iron acquisition. Nat Commun 2017; 8:14888. [PMID: 28348410 PMCID: PMC5379069 DOI: 10.1038/ncomms14888] [Citation(s) in RCA: 195] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 02/09/2017] [Indexed: 01/20/2023] Open
Abstract
Iron sequestration by host proteins contributes to the defence against bacterial pathogens, which need iron for their metabolism and virulence. A Pseudomonas aeruginosa mutant lacking all three known iron acquisition systems retains the ability to grow in media containing iron chelators, suggesting the presence of additional pathways involved in iron uptake. Here we screen P. aeruginosa mutants defective in growth in iron-depleted media and find that gene PA2374, proximal to the type VI secretion system H3 (H3-T6SS), functions synergistically with known iron acquisition systems. PA2374 (which we have renamed TseF) appears to be secreted by H3-T6SS and is incorporated into outer membrane vesicles (OMVs) by directly interacting with the iron-binding Pseudomonas quinolone signal (PQS), a cell–cell signalling compound. TseF facilitates the delivery of OMV-associated iron to bacterial cells by engaging the Fe(III)-pyochelin receptor FptA and the porin OprF. Our results reveal links between type VI secretion, cell–cell signalling and classic siderophore receptors for iron acquisition in P. aeruginosa. Pathogens require iron for their metabolism and virulence. Here the authors identify an iron acquisition system in Pseudomonas aeruginosa involving a protein secreted by a type VI secretion system, the PQS signalling compound and siderophore receptors.
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An Y, Wang J, Li C, Revote J, Zhang Y, Naderer T, Hayashida M, Akutsu T, Webb GI, Lithgow T, Song J. SecretEPDB: a comprehensive web-based resource for secreted effector proteins of the bacterial types III, IV and VI secretion systems. Sci Rep 2017; 7:41031. [PMID: 28112271 PMCID: PMC5253721 DOI: 10.1038/srep41031] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 12/14/2016] [Indexed: 12/28/2022] Open
Abstract
Bacteria translocate effector molecules to host cells through highly evolved secretion systems. By definition, the function of these effector proteins is to manipulate host cell biology and the sequence, structural and functional annotations of these effector proteins will provide a better understanding of how bacterial secretion systems promote bacterial survival and virulence. Here we developed a knowledgebase, termed SecretEPDB (Bacterial Secreted Effector Protein DataBase), for effector proteins of type III secretion system (T3SS), type IV secretion system (T4SS) and type VI secretion system (T6SS). SecretEPDB provides enriched annotations of the aforementioned three classes of effector proteins by manually extracting and integrating structural and functional information from currently available databases and the literature. The database is conservative and strictly curated to ensure that every effector protein entry is supported by experimental evidence that demonstrates it is secreted by a T3SS, T4SS or T6SS. The annotations of effector proteins documented in SecretEPDB are provided in terms of protein characteristics, protein function, protein secondary structure, Pfam domains, metabolic pathway and evolutionary details. It is our hope that this integrated knowledgebase will serve as a useful resource for biological investigation and the generation of new hypotheses for research efforts aimed at bacterial secretion systems.
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Affiliation(s)
- Yi An
- College of Information Engineering, Northwest A&F University, Yangling 712100, China.,Monash Centre for Data Science, Faculty of Information Technology, Monash University, Melbourne, VIC 3800, Australia
| | - Jiawei Wang
- School of Electronic and Computer Engineering, Peking University, Beijing 100871, China
| | - Chen Li
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, VIC 3800, Australia
| | - Jerico Revote
- Monash Bioinformatics Platform, Monash University, Melbourne, VIC 3800, Australia
| | - Yang Zhang
- College of Information Engineering, Northwest A&F University, Yangling 712100, China
| | - Thomas Naderer
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC 3800, Australia
| | - Morihiro Hayashida
- Bioinformatics Center, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Tatsuya Akutsu
- Bioinformatics Center, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Geoffrey I Webb
- Monash Centre for Data Science, Faculty of Information Technology, Monash University, Melbourne, VIC 3800, Australia
| | - Trevor Lithgow
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, VIC 3800, Australia
| | - Jiangning Song
- Monash Centre for Data Science, Faculty of Information Technology, Monash University, Melbourne, VIC 3800, Australia.,Infection and Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC 3800, Australia
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50
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Khoei NS, Lampis S, Zonaro E, Yrjälä K, Bernardi P, Vallini G. Insights into selenite reduction and biogenesis of elemental selenium nanoparticles by two environmental isolates of Burkholderia fungorum. N Biotechnol 2016; 34:1-11. [PMID: 27717878 DOI: 10.1016/j.nbt.2016.10.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 07/11/2016] [Accepted: 10/03/2016] [Indexed: 11/30/2022]
Abstract
Microorganisms capable of transforming toxic selenium oxyanions into non-toxic elemental selenium (Se°) may be considered as biocatalysts for the production of selenium nanoparticles (SeNPs), eventually exploitable in different biotechnological applications. Two Burkholderia fungorum strains (B. fungorum DBT1 and B. fungorum 95) were monitored during their growth for both capacity and efficiency of selenite (SeO32-) reduction and elemental selenium formation. Both strains are environmental isolates in origin: B. fungorum DBT1 was previously isolated from an oil refinery drainage, while B. fungorum 95 has been enriched from inner tissues of hybrid poplars grown in a soil contaminated by polycyclic aromatic hydrocarbons. Our results showed that B. fungorum DBT1 is able to reduce 0.5mM SeO32- to Se° when cultured aerobically in liquid medium at 27°C, while B. fungorum 95 can reduce more than 1mM SeO32- to Se° within 96h under the same growth conditions, with the appearance of SeNPs in cultures of both bacterial strains. Biogenic SeNPs were spherical, with pH-dependent charge and an average hydrodynamic diameter of 170nm and 200nm depending on whether they were produced by B. fungorum 95 or B. fungorum DBT1, respectively. Electron microscopy analyses evidenced that Se nanoparticles occurred intracellularly and extracellularly. The mechanism of SeNPs formation can be tentatively attributed to cytoplasmic enzymatic activation mediated by electron donors. Biogenic nanoparticles were then probably released outside the bacterial cells as a consequence of a secretory process or cell lysis. Nevertheless, formation of elemental selenium nanoparticles under aerobic conditions by B. fungorum DBT1 and B. fungorum 95 is likely due to intracellular reduction mechanisms. Biomedical and other high tech sectors might exploit these biogenic nanoparticles in the near future, once fully characterized and tested for their multiple properties.
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Affiliation(s)
- Nazanin Seyed Khoei
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy.
| | - Silvia Lampis
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy.
| | - Emanuele Zonaro
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Kim Yrjälä
- MEM-group, Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland
| | - Paolo Bernardi
- Department of Neurological and Movement Sciences, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy
| | - Giovanni Vallini
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy
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