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Killiny N, Jones SE. A Transmission Assay of ' Candidatus Liberibacter asiaticus' Using Citrus Phloem Sap and Topical Feeding to Its Insect Vector, Diaphorina citri. PHYTOPATHOLOGY 2024:PHYTO05240171SC. [PMID: 38916945 DOI: 10.1094/phyto-05-24-0171-sc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
'Candidatus Liberibacter asiaticus', the putative causal agent of citrus greening disease, is transmitted by the Asian citrus psyllid, Diaphorina citri, in a propagative, circulative, and persistent manner. Unfortunately, 'Ca. L. asiaticus' is not yet available in pure culture to carry out Koch's postulates and to confirm its etiology. When a pure culture is available, an assay to test its infectivity in both the insect vector and the plant host will be crucial. Herein, we described a transmission assay based on the use of phloem sap extracted from infected citrus plants and topical feeding to D. citri nymphs. Phloem sap was collected by centrifugation, diluted with 0.1 M phosphate buffer pH 7.4 containing 20% (wt/vol) sucrose and 0.1% ascorbic acid (wt/vol) as an antioxidant, and delivered to third through fifth instar nymphs by placing droplets on the mouthparts. Nymphs unfolded the stylets and acquired the phloem sap containing the bacterial pathogen. Nymphs were then placed onto Citrus macrophylla seedlings (10 nymphs per seedling) for an inoculation period of 2 weeks. A transmission rate of up to 80% was recorded at 6 months postinoculation. The method could be a powerful tool to test the transmissibility of the bacterial pathogen after various treatments to reduce the viability of the bacteria or to block its transmission. In addition, it might be a potent assay to achieve Koch's postulates if a pure culture of 'Ca. L. asiaticus' becomes available.
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Affiliation(s)
- Nabil Killiny
- Department of Plant Pathology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850
| | - Shelley E Jones
- Department of Plant Pathology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850
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Campos Vieira F, Blacutt A, Drozd C, Viravathana P, Ginnan N, Roper MC. Thirteen draft genome assemblies of Bacillus spp. isolated from HLB-impacted citrus trees. Microbiol Resour Announc 2024:e0060224. [PMID: 39254041 DOI: 10.1128/mra.00602-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Accepted: 08/19/2024] [Indexed: 09/11/2024] Open
Abstract
We report the draft genome assembly, annotation, and phylogenetic placement of 13 Bacillus spp. isolates isolated from citrus groves under high (Florida) or low (California) Huanglongbing disease pressure.
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Affiliation(s)
- Flávia Campos Vieira
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, USA
| | - Alex Blacutt
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, USA
| | - Christopher Drozd
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, USA
| | - Polrit Viravathana
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, USA
| | - Nichole Ginnan
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, USA
| | - M Caroline Roper
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, USA
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A Aksenov A, Blacutt A, Ginnan N, Rolshausen PE, V Melnik A, Lotfi A, C Gentry E, Ramasamy M, Zuniga C, Zengler K, Mandadi KK, Dorrestein PC, Roper MC. Spatial chemistry of citrus reveals molecules bactericidal to Candidatus Liberibacter asiaticus. Sci Rep 2024; 14:20306. [PMID: 39218988 PMCID: PMC11366753 DOI: 10.1038/s41598-024-70499-z] [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: 04/05/2024] [Accepted: 08/16/2024] [Indexed: 09/04/2024] Open
Abstract
Huanglongbing (HLB), associated with the psyllid-vectored phloem-limited bacterium, Candidatus Liberibacter asiaticus (CLas), is a disease threat to all citrus production worldwide. Currently, there are no sustainable curative or prophylactic treatments available. In this study, we utilized mass spectrometry (MS)-based metabolomics in combination with 3D molecular mapping to visualize complex chemistries within plant tissues to explore how these chemistries change in vivo in HLB-infected trees. We demonstrate how spatial information from molecular maps of branches and single leaves yields insight into the biology not accessible otherwise. In particular, we found evidence that flavonoid biosynthesis is disrupted in HLB-infected trees, and an increase in the polyamine, feruloylputrescine, is highly correlated with an increase in disease severity. Based on mechanistic details revealed by these molecular maps, followed by metabolic modeling, we formulated and tested the hypothesis that CLas infection either directly or indirectly converts the precursor compound, ferulic acid, to feruloylputrescine to suppress the antimicrobial effects of ferulic acid and biosynthetically downstream flavonoids. Using in vitro bioassays, we demonstrated that ferulic acid and bioflavonoids are indeed highly bactericidal to CLas, with the activity on par with a reference antibiotic, oxytetracycline, recently approved for HLB management. We propose these compounds should be evaluated as therapeutics alternatives to the antibiotics for HLB treatment. Overall, the utilized 3D metabolic mapping approach provides a promising methodological framework to identify pathogen-specific inhibitory compounds in planta for potential prophylactic or therapeutic applications.
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Affiliation(s)
- Alexander A Aksenov
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California - San Diego, La Jolla, CA, USA.
- Arome Science Inc., Farmington, CT, USA.
- Department of Chemistry, University of Connecticut, Storrs, CT, USA.
| | - Alex Blacutt
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA
| | - Nichole Ginnan
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA
- One Health Microbiome Center, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA
| | - Philippe E Rolshausen
- Department of Botany and Plant Sciences, University of California, Riverside, CA, USA
| | - Alexey V Melnik
- Department of Chemistry, University of Connecticut, Storrs, CT, USA
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California - San Diego, La Jolla, CA, USA
- Arome Science Inc., Farmington, CT, USA
| | - Ali Lotfi
- Department of Chemistry, University of Connecticut, Storrs, CT, USA
| | - Emily C Gentry
- Department of Chemistry, University of Connecticut, Storrs, CT, USA
- Department of Chemistry, Virginia Tech, Blacksburg, VA, USA
| | - Manikandan Ramasamy
- Department of Plant Pathology and Microbiology, Texas A&M AgriLife Research and Extension Center, Weslaco, TX, USA
| | - Cristal Zuniga
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Karsten Zengler
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
- Center for Microbiome Innovation, University of California, San Diego, La Jolla, CA, USA
| | - Kranthi K Mandadi
- Department of Plant Pathology and Microbiology, Texas A&M AgriLife Research and Extension Center, Weslaco, TX, USA
- Institute for Advancing Health Through Agriculture, Texas A&M AgriLife, College Station, TX, USA
| | - Pieter C Dorrestein
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California - San Diego, La Jolla, CA, USA
- Center for Microbiome Innovation, University of California, San Diego, La Jolla, CA, USA
| | - M Caroline Roper
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA
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Lombardo MF, Zhang Y, Xu J, Trivedi P, Zhang P, Riera N, Li L, Wang Y, Liu X, Fan G, Tang J, Coletta-Filho HD, Cubero J, Deng X, Ancona V, Lu Z, Zhong B, Roper MC, Capote N, Catara V, Pietersen G, Al-Sadi AM, Xu X, Wang J, Yang H, Jin T, Cirvilleri G, Wang N. Global citrus root microbiota unravels assembly cues and core members. Front Microbiol 2024; 15:1405751. [PMID: 39132141 PMCID: PMC11310164 DOI: 10.3389/fmicb.2024.1405751] [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: 03/23/2024] [Accepted: 07/09/2024] [Indexed: 08/13/2024] Open
Abstract
Introduction Citrus is one of the most important fruit crops worldwide, and the root-associated microbiota can have a profound impact on tree health and growth. Methods In a collaborative effort, the International Citrus Microbiome Consortium investigated the global citrus root microbiota with samples collected from nine citrus-producing countries across six continents. We analyzed 16S rDNA and ITS2 amplicon sequencing data to identify predominant prokaryotic and fungal taxa in citrus root samples. Comparative analyses were conducted between root-associated microbial communities and those from the corresponding rhizosphere and bulk soil samples. Additionally, genotype-based group-wise comparisons were performed to assess the impact of citrus genotype on root microbiota composition. Results Ten predominant prokaryotic phyla, containing nine bacterial phyla including Proteobacteria, Actinobacteria, Acidobacteria, and Bacteroidetes and one archaeal phylum (Thaumarchaeota), and multiple fungal phyla including Ascomycota and Basidiomycota were identified in the citrus root samples. Compared with the microbial communities from the corresponding rhizosphere and bulk soil samples from the same trees, the prokaryotic and fungal communities in the roots exhibited lower diversity and complexity but greater modularity compared to those in the rhizosphere. In total, 30 root-enriched and 150 root-depleted genera in bacterial community were identified, whereas 21 fungal genera were enriched, and 147 fungal genera were depleted in the root niche compared with the rhizosphere. The citrus genotype significantly affected the root prokaryotic and fungal communities. In addition, we have identified the core root prokaryotic genera comprising Acidibacter, Allorhizobium, Bradyrhizobium, Chitinophaga, Cupriavidus, Devosia, Dongia, Niastella, Pseudomonas, Sphingobium, Steroidobacter and Streptomyces, and the core fungal genera including Acrocalymma, Cladosporium, Fusarium, Gibberella, Mortierella, Neocosmospora and Volutella. The potential functions of these core genera of root microbiota were predicted. Conclusion Overall, this study provides new insights into the assembly of microbial communities and identifies core members of citrus root microbiota across a wide geographic range. The findings offer valuable information for manipulating root microbiota to enhance plant growth and health.
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Affiliation(s)
- Monia F. Lombardo
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences (IFAS), University of Florida, Lake Alfred, FL, United States
- Department of Agriculture, Food and Environment (Di3A), University of Catania, Catania, Italy
| | - Yunzeng Zhang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences (IFAS), University of Florida, Lake Alfred, FL, United States
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, Jiangsu, China
| | - Jin Xu
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences (IFAS), University of Florida, Lake Alfred, FL, United States
| | - Pankaj Trivedi
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO, United States
| | | | - Nadia Riera
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences (IFAS), University of Florida, Lake Alfred, FL, United States
| | - Lei Li
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences (IFAS), University of Florida, Lake Alfred, FL, United States
| | - Yayu Wang
- BGI-Shenzhen, Shenzhen, Guangdong, China
| | - Xin Liu
- BGI-Shenzhen, Shenzhen, Guangdong, China
| | | | - Jiliang Tang
- The State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning, Guangxi, China
| | - Helvécio D. Coletta-Filho
- Instituto Agronômico, IAC Centro de Citricultura Sylvio Moreira, CCSM, Cordeirópolis, São Paulo, Brazil
| | - Jaime Cubero
- Department of Plant Protection, National Institute for Agricultural and Food Research and Technology (INIA-CSIC), Madrid, Spain
| | - Xiaoling Deng
- Department of Plant Pathology, South China Agricultural University, Guangzhou, China
| | - Veronica Ancona
- Texas A&M University-Kingsville Citrus Center, Weslaco, TX, United States
| | - Zhanjun Lu
- National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi, China
| | - Balian Zhong
- National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi, China
| | - M. Caroline Roper
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA, United States
| | | | - Vittoria Catara
- Department of Agriculture, Food and Environment (Di3A), University of Catania, Catania, Italy
| | - Gerhard Pietersen
- Department of Genetics, University of Stellenbosch, Stellenbosch, South Africa
| | | | - Xun Xu
- BGI-Shenzhen, Shenzhen, Guangdong, China
| | - Jian Wang
- BGI-Shenzhen, Shenzhen, Guangdong, China
| | | | - Tao Jin
- BGI-Shenzhen, Shenzhen, Guangdong, China
| | - Gabriella Cirvilleri
- Department of Agriculture, Food and Environment (Di3A), University of Catania, Catania, Italy
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences (IFAS), University of Florida, Lake Alfred, FL, United States
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Mallawarachchi S, Wang H, Mulgaonkar N, Irigoyen S, Padilla C, Mandadi K, Borneman J, Fernando S. Specifically targeting antimicrobial peptides for inhibition of Candidatus Liberibacter asiaticus. J Appl Microbiol 2024; 135:lxae061. [PMID: 38509024 DOI: 10.1093/jambio/lxae061] [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: 12/01/2023] [Revised: 02/21/2024] [Accepted: 03/19/2024] [Indexed: 03/22/2024]
Abstract
AIMS Huanglongbing (citrus greening) is a plant disease putatively caused by the unculturable Gram-negative bacterium Candidatus Liberibacter asiaticus (CLas), and it has caused severe damage to citrus plantations worldwide. There are no definitive treatments for this disease, and conventional disease control techniques have shown limited efficacy. This work presents an in silico evaluation of using specifically targeting anti-microbial peptides (STAMPs) consisting of a targeting segment and an antimicrobial segment to inhibit citrus greening by inhibiting the BamA protein of CLas, which is an outer membrane protein crucial for bacterial viability. METHODS AND RESULTS Initially, a set of peptides with a high affinity toward BamA protein were screened and evaluated via molecular docking and molecular dynamics simulations and were verified in vitro via bio-layer interferometry (BLI). In silico studies and BLI experiments indicated that two peptides, HASP2 and HASP3, showed stable binding to BamA. Protein structures for STAMPs were created by fusing known anti-microbial peptides (AMPs) with the selected short peptides. The binding of STAMPs to BamA was assessed using molecular docking and binding energy calculations. The attachment of high-affinity short peptides significantly reduced the free energy of binding for AMPs, suggesting that it would make it easier for the STAMPs to bind to BamA. Efficacy testing in vitro using a closely related CLas surrogate bacterium showed that STAMPs had greater inhibitory activity than AMP alone. CONCLUSIONS In silico and in vitro results indicate that the STAMPs can inhibit CLas surrogate Rhizobium grahamii more effectively compared to AMPs, suggesting that STAMPs can achieve better inhibition of CLas, potentially via enhancing the site specificity of AMPs.
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Affiliation(s)
- Samavath Mallawarachchi
- Department of Biological and Agricultural Engineering, Texas A&M University, College Station, TX 77843, United States
| | - Haoqi Wang
- Department of Biological and Agricultural Engineering, Texas A&M University, College Station, TX 77843, United States
| | - Nirmitee Mulgaonkar
- Department of Biological and Agricultural Engineering, Texas A&M University, College Station, TX 77843, United States
| | - Sonia Irigoyen
- Texas A&M AgriLife Research & Extension Center, Texas A&M University System, 2415 E Highway 83, Weslaco, TX 78596, United States
| | - Carmen Padilla
- Texas A&M AgriLife Research & Extension Center, Texas A&M University System, 2415 E Highway 83, Weslaco, TX 78596, United States
| | - Kranthi Mandadi
- Texas A&M AgriLife Research & Extension Center, Texas A&M University System, 2415 E Highway 83, Weslaco, TX 78596, United States
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, United States
- Institute for Advancing Health through Agriculture, Texas A&M AgriLife, College Station, TX 77843, United States
| | - James Borneman
- Department of Microbiology & Plant Pathology, University of California Riverside, Riverside, CA 92521, United States
| | - Sandun Fernando
- Department of Biological and Agricultural Engineering, Texas A&M University, College Station, TX 77843, United States
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Sohaib H, Fays M, Khatib A, Rivière J, El Aouad N, Desoignies N. Contribution to the characterization of the seed endophyte microbiome of Argania spinosa across geographical locations in Central Morocco using metagenomic approaches. Front Microbiol 2024; 15:1310395. [PMID: 38601940 PMCID: PMC11005822 DOI: 10.3389/fmicb.2024.1310395] [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: 10/09/2023] [Accepted: 03/08/2024] [Indexed: 04/12/2024] Open
Abstract
Microbial endophytes are microorganisms that live inside plants, and some of them play important yet understudied roles in plant health, growth, and adaptation to environmental conditions. Their diversity within plants has traditionally been underestimated due to the limitations of culture-dependent techniques. Metagenomic profiling provides a culture-independent approach to characterize entire microbial communities. The argan tree (Argania spinosa) is ecologically and economically important in Morocco, yet its seed endophyte microbiome remains unexplored. This study aimed to compare the bacterial and fungal endophyte communities associated with argan seeds collected from six sites across Morocco using Illumina MiSeq sequencing of the 16S rRNA gene and ITS regions, respectively. Bacterial DNA was extracted from surface-sterilized seeds and amplified using universal primers, while fungal DNA was isolated directly from seeds. Bioinformatics analysis of sequencing data identified taxonomic profiles at the phylum to genus levels. The results indicated that bacterial communities were dominated by the genus Rhodoligotrophos, while fungal communities exhibited varying degrees of dominance between Ascomycota and Basidiomycota depending on site, with Penicillium being the most abundant overall. Distinct site-specific profiles were observed, with Pseudomonas, Bacillus, and Aspergillus present across multiple locations. Alpha diversity indices revealed variation in endophyte richness between seed sources. In conclusion, this first exploration of the argan seed endophyte microbiome demonstrated environmental influence on community structure. While facing limitations due to small sample sizes and lack of ecological metadata, it provides a foundation for future mechanistic investigations into how specific endophyte-host interactions shape argan adaptation across Morocco's diverse landscapes.
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Affiliation(s)
- Hourfane Sohaib
- Laboratory of Life and Health Sciences, Faculty of Medicine and Pharmacy of Tangier, University Abdelmalek Essaâdi, Tetouan, Morocco
| | - Morgan Fays
- Phytopathology, Microbial and Molecular Farming Lab, Centre D’Etudes et Recherche Appliquée-Haute Ecole Provinciale du Hainaut Condorcet, Ath, Belgium
| | - Abderrezzak Khatib
- Laboratory of Life and Health Sciences, Faculty of Medicine and Pharmacy of Tangier, University Abdelmalek Essaâdi, Tetouan, Morocco
| | - John Rivière
- Laboratory of Biotechnology and Applied Biology, Haute Ecole Provinciale de Hainaut-Condorcet, Ath, Hainaut, Belgium
| | - Noureddine El Aouad
- Laboratory of Life and Health Sciences, Faculty of Medicine and Pharmacy of Tangier, University Abdelmalek Essaâdi, Tetouan, Morocco
| | - Nicolas Desoignies
- Phytopathology, Microbial and Molecular Farming Lab, Centre D’Etudes et Recherche Appliquée-Haute Ecole Provinciale du Hainaut Condorcet, Ath, Belgium
- University of Liege - Gembloux Agro-Bio Tech, TERRA - Teaching and Research Center, Plant Sciences Axis, Gembloux, Belgium
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Xia K, Feng Z, Zhang X, Zhou Y, Zhu H, Yao Q. Potential functions of the shared bacterial taxa in the citrus leaf midribs determine the symptoms of Huanglongbing. FRONTIERS IN PLANT SCIENCE 2023; 14:1270929. [PMID: 38034569 PMCID: PMC10682189 DOI: 10.3389/fpls.2023.1270929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 10/30/2023] [Indexed: 12/02/2023]
Abstract
Instruction Citrus is a globally important fruit tree whose microbiome plays a vital role in its growth, adaptability, and resistance to stress. Methods With the high throughput sequencing of 16S rRNA genes, this study focused on analyzing the bacterial community, especially in the leaf midribs, of healthy and Huanglongbing (HLB)-infected plants. Results We firstly identified the shared bacterial taxa in the midribs of both healthy and HLB-infected plants, and then analyzed their functions. Results showed that the shared bacterial taxa in midribs belonged to 62 genera, with approximately 1/3 of which modified in the infected samples. Furthermore, 366 metabolic pathways, 5851 proteins, and 1833 enzymes in the shared taxa were predicted. Among these, three metabolic pathways and one protein showed significant importance in HLB infection. With the random forest method, six genera were identified to be significantly important for HLB infection. Notably, four of these genera were also among the significantly different shared taxa. Further functional characterization of these four genera revealed that Pseudomonas and Erwinia likely contributed to plant defense against HLB, while Streptomyces might have implications for plant defense against HLB or the pathogenicity of Candidatus Liberibacter asiaticus (CLas). Disccusion Overall, our study highlights that the functions of the shared taxa in leaf midribs are distinguished between healthy and HLB-infected plants, and these microbiome-based findings can contribute to the management and protection of citrus crops against CLas.
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Affiliation(s)
- Kaili Xia
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China), Ministry of Agriculture and Rural Affairs, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Horticulture, South China Agricultural University, Guangzhou, China
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Zengwei Feng
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Xianjiao Zhang
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China), Ministry of Agriculture and Rural Affairs, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Horticulture, South China Agricultural University, Guangzhou, China
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Yang Zhou
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Honghui Zhu
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Qing Yao
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China), Ministry of Agriculture and Rural Affairs, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Horticulture, South China Agricultural University, Guangzhou, China
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Kennedy JP, Wood K, Pitino M, Mandadi K, Igwe DO, Shatters RG, Widmer TL, Niedz R, Heck M. A Perspective on Current Therapeutic Molecule Screening Methods Against ' Candidatus Liberibacter asiaticus', the Presumed Causative Agent of Citrus Huanglongbing. PHYTOPATHOLOGY 2023; 113:1171-1179. [PMID: 36750555 DOI: 10.1094/phyto-12-22-0455-per] [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: 06/18/2023]
Abstract
Huanglongbing (HLB), referred to as citrus greening disease, is a bacterial disease impacting citrus production worldwide and is fatal to young trees and mature trees of certain varieties. In some areas, the disease is devastating the citrus industry. A successful solution to HLB will be measured in economics: citrus growers need treatments that improve tree health, fruit production, and most importantly, economic yield. The profitability of citrus groves is the ultimate metric that truly matters when searching for solutions to HLB. Scientific approaches used in the laboratory, greenhouse, or field trials are critical to the discovery of those solutions and to estimate the likelihood of success of a treatment aimed at commercialization. Researchers and the citrus industry use a number of proxy evaluations of potential HLB solutions; understanding the strengths and limitations of each assay, as well as how best to compare different assays, is critical for decision-making to advance therapies into field trials and commercialization. This perspective aims to help the reader compare and understand the limitations of different proxy evaluation systems based on the treatment and evaluation under consideration. The researcher must determine the suitability of one or more of these metrics to identify treatments and predict the usefulness of these treatments in having an eventual impact on citrus production and HLB mitigation. As therapies advance to field trials in the next few years, a reevaluation of these metrics will be useful to guide future research efforts on strategies to mitigate HLB and vascular bacterial pathogens in other perennial crops.
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Affiliation(s)
- John Paul Kennedy
- U.S. Horticultural Research Laboratory, U.S. Department of Agriculture-Agricultural Research Service, Fort Pierce, FL 34945
| | | | | | - Kranthi Mandadi
- Department of Plant Pathology and Microbiology, Texas A&M AgriLife Research and Extension Center, Weslaco, TX 78596
- Texas A&M AgriLife Institute for Advancing Health Through Agriculture, Texas A&M AgriLife, College Station, TX 77843
| | - David O Igwe
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853
| | - Robert G Shatters
- U.S. Horticultural Research Laboratory, U.S. Department of Agriculture-Agricultural Research Service, Fort Pierce, FL 34945
| | - Timothy L Widmer
- U.S. Department of Agriculture-Agricultural Research Service, Beltsville, MD 20705
| | - Randall Niedz
- U.S. Horticultural Research Laboratory, U.S. Department of Agriculture-Agricultural Research Service, Fort Pierce, FL 34945
| | - Michelle Heck
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853
- Emerging Pests and Pathogens Research Unit, U.S. Department of Agriculture-Agricultural Research Service, Ithaca, NY 14853
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Dominguez J, Jayachandran K, Stover E, Krystel J, Shetty KG. Endophytes and Plant Extracts as Potential Antimicrobial Agents against Candidatus Liberibacter Asiaticus, Causal Agent of Huanglongbing. Microorganisms 2023; 11:1529. [PMID: 37375030 DOI: 10.3390/microorganisms11061529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/02/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
Huanglongbing (HLB), also known as citrus greening, is an insidious disease in citrus and has become a threat to the sustainability of the citrus industry worldwide. In the U.S., Candidatus Liberibacter asiaticus (CLas) is the pathogen that is associated with HLB, an unculturable, phloem-limited bacteria, vectored by the Asian Citrus Psyllid (ACP, Diaphorina citri). There is no known cure nor treatment to effectively control HLB, and current control methods are primarily based on the use of insecticides and antibiotics, where effectiveness is limited and may have negative impacts on beneficial and non-target organisms. Thus, there is an urgent need for the development of effective and sustainable treatment options to reduce or eliminate CLas from infected trees. In the present study, we screened citrus-derived endophytes, their cell-free culture supernatants (CFCS), and crude plant extracts for antimicrobial activity against two culturable surrogates of CLas, Sinorhizobium meliloti and Liberibacter crescens. Candidates considered high-potential antimicrobial agents were assessed directly against CLas in vitro, using a propidium monoazide-based assay. As compared to the negative controls, statistically significant reductions of viable CLas cells were observed for each of the five bacterial CFCS. Subsequent 16S rRNA gene sequencing revealed that each of the five bacterial isolates were most closely related to Bacillus amyloliquefaciens, a species dominating the market of biological control products. As such, the aboveground endosphere of asymptomatic survivor citrus trees, grown in an organic orchard, were found to host bacterial endophytes capable of effectively disrupting CLas cell membranes. These results concur with the theory that native members of the citrus microbiome play a role in the development of HLB. Here, we identify five strains of Bacillus amyloliquefaciens demonstrating notable potential to be used as sources of novel antimicrobials for the sustainable management of HLB.
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Affiliation(s)
- Jessica Dominguez
- Department of Earth and Environment, Florida International University, Miami, FL 33199, USA
| | | | - Ed Stover
- United States Department of Agriculture/Agricultural Research Service, Ft. Pierce, FL 34945, USA
| | - Joseph Krystel
- United States Department of Agriculture/Agricultural Research Service, Ft. Pierce, FL 34945, USA
| | - Kateel G Shetty
- Department of Earth and Environment, Florida International University, Miami, FL 33199, USA
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10
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Liu HQ, Zhao ZL, Li HJ, Yu SJ, Cong L, Ding LL, Ran C, Wang XF. Accurate prediction of huanglongbing occurrence in citrus plants by machine learning-based analysis of symbiotic bacteria. FRONTIERS IN PLANT SCIENCE 2023; 14:1129508. [PMID: 37313258 PMCID: PMC10258322 DOI: 10.3389/fpls.2023.1129508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 05/02/2023] [Indexed: 06/15/2023]
Abstract
Huanglongbing (HLB), the most prevalent citrus disease worldwide, is responsible for substantial yield and economic losses. Phytobiomes, which have critical effects on plant health, are associated with HLB outcomes. The development of a refined model for predicting HLB outbreaks based on phytobiome markers may facilitate early disease detection, thus enabling growers to minimize damages. Although some investigations have focused on differences in the phytobiomes of HLB-infected citrus plants and healthy ones, individual studies are inappropriate for generating common biomarkers useful for detecting HLB on a global scale. In this study, we therefore obtained bacterial information from several independent datasets representing hundreds of citrus samples from six continents and used these data to construct HLB prediction models based on 10 machine learning algorithms. We detected clear differences in the phyllosphere and rhizosphere microbiomes of HLB-infected and healthy citrus samples. Moreover, phytobiome alpha diversity indices were consistently higher for healthy samples. Furthermore, the contribution of stochastic processes to citrus rhizosphere and phyllosphere microbiome assemblies decreased in response to HLB. Comparison of all constructed models indicated that a random forest model based on 28 bacterial genera in the rhizosphere and a bagging model based on 17 bacterial species in the phyllosphere predicted the health status of citrus plants with almost 100% accuracy. Our results thus demonstrate that machine learning models and phytobiome biomarkers may be applied to evaluate the health status of citrus plants.
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Affiliation(s)
- Hao-Qiang Liu
- Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, National Engineering Research Center for Citrus, Chongqing, China
| | - Ze-long Zhao
- Shanghai BIOZERON Biotechnology Co., Ltd., Shanghai, China
| | - Hong-Jun Li
- Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, National Engineering Research Center for Citrus, Chongqing, China
| | - Shi-Jiang Yu
- Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, National Engineering Research Center for Citrus, Chongqing, China
| | - Lin Cong
- Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, National Engineering Research Center for Citrus, Chongqing, China
| | - Li-Li Ding
- Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, National Engineering Research Center for Citrus, Chongqing, China
| | - Chun Ran
- Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, National Engineering Research Center for Citrus, Chongqing, China
| | - Xue-Feng Wang
- Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, National Engineering Research Center for Citrus, Chongqing, China
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11
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Neogrisphenol A, a Potential Ovarian Cancer Inhibitor from a New Record Fungus Neohelicosporium griseum. Metabolites 2023; 13:metabo13030435. [PMID: 36984875 PMCID: PMC10055829 DOI: 10.3390/metabo13030435] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 03/03/2023] [Accepted: 03/13/2023] [Indexed: 03/19/2023] Open
Abstract
From the rice fermentation product of a new record fungus, Neohelicosporium griseum, two new polyketides, neogrisphenol A (1) and neogrisphenol B (2), one new isochroman-1-one, (S)-6-hydroxy-7-methoxy-3,5-dimethylisochroman-1-one (3), and four known compounds (4–7) were isolated. Their structures were determined using 1D- and 2D-NMR, mass spectrometry, and chemical calculations. The C-3~C-2′ polymerization mode between the two α-naphthalenone derivative moieties is uncommon in compounds 1 and 2. Meanwhile, compounds 1–2 and 5 exhibited antibacterial activity against Bacillus subtilis, Clostridium perfringens, Staphylococcus aureus, and Staphylococcus aureus, with MIC values ranging between 16 and 31 µg/mL. In addition, compound 5 showed antifungal activity against Sclerotinia sclerotiorum and Phytophthora nicotianae var. nicotianae, with respective IC50 values of 88.14 ± 2.21 µg/mL and 52.36 ± 1.38 µg/mL. Compound 1 showed significant cytotoxicity against A2780, PC-3, and MBA-MD-231 cell lines with respective IC50 values of 3.20, 10.68, and 16.30 µM, and the cytotoxicity against A2780 cells was even higher than that of cisplatin (CDDP). With an IC50 value of 10.13 µM, compound 2 also exhibited cytotoxicity against A2780. The in vitro results showed that compound 1 inhibited A2780 cell proliferation, induced apoptosis, and arrested the cell cycle at the S-phase in a concentration-dependent manner.
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12
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de Moraes Pontes JG, da Silva Pinheiro MS, Fill TP. Unveiling Chemical Interactions Between Plants and Fungi Using Metabolomics Approaches. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1439:1-20. [PMID: 37843803 DOI: 10.1007/978-3-031-41741-2_1] [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: 10/17/2023]
Abstract
Metabolomics has been extensively used in clinical studies in the search for new biomarkers of human diseases. However, this approach has also been highlighted in agriculture and biological sciences, once metabolomics studies have been assisting researchers to deduce new chemical mechanisms involved in biological interactions that occur between microorganisms and plants. In this sense, the knowledge of the biological role of each metabolite (virulence factors, signaling compounds, antimicrobial metabolites, among others) and the affected biochemical pathways during the interaction contribute to a better understand of different ecological relationships established in nature. The current chapter addresses five different applications of the metabolomics approach in fungal-plant interactions research: (1) Discovery of biomarkers in pathogen-host interactions, (2) plant diseases diagnosis, (3) chemotaxonomy, (4) plant defense, and (5) plant resistance; using mass spectrometry and/or nuclear magnetic resonance spectroscopy, which are the techniques most used in metabolomics.
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Affiliation(s)
- João Guilherme de Moraes Pontes
- Universidade Estadual de Campinas (UNICAMP), Instituto de Química, Laboratório de Biologia Química Microbiana (LaBioQuiMi), Campinas, SP, Brazil
| | - Mayra Suelen da Silva Pinheiro
- Universidade Estadual de Campinas (UNICAMP), Instituto de Química, Laboratório de Biologia Química Microbiana (LaBioQuiMi), Campinas, SP, Brazil
| | - Taícia Pacheco Fill
- Universidade Estadual de Campinas (UNICAMP), Instituto de Química, Laboratório de Biologia Química Microbiana (LaBioQuiMi), Campinas, SP, Brazil.
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13
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Xi M, Deyett E, Stajich JE, El-Kereamy A, Roper MC, Rolshausen PE. Microbiome diversity, composition and assembly in a California citrus orchard. Front Microbiol 2023; 14:1100590. [PMID: 36910183 PMCID: PMC9992537 DOI: 10.3389/fmicb.2023.1100590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 02/03/2023] [Indexed: 02/24/2023] Open
Abstract
The citrus root and rhizosphere microbiomes have been relatively well described in the literature, especially in the context of Huanglonbing disease. Yet questions addressing the assembly of root microbial endophytes have remained unanswered. In the above ground tree tissues, leaves and stems have been the research focus point, while flush and flower microbiomes, two important tissues in the vegetative and reproductive cycles of the tree, are not well described. In this study, the fungal and bacterial taxa in five biocompartments (bulk soil, rhizosphere, root endosphere, flower and flush) of citrus trees grown in a single California orchard were profiled using an amplicon-based metagenomic Illumina sequencing approach. Trees with no observable signs of abiotic or biotic stresses were sampled for two consecutive years during the floral development phase. The rhizosphere was the most biodiverse compartment compared to bulk soil, root endosphere, flower and flush microbiomes. In addition, the belowground bacteriome was more diverse than the mycobiome. Microbial richness decreased significantly from the root exosphere to the endosphere and was overall low in the above ground tissues. Root endophytic microbial community composition shared strong similarities to the rhizosphere but also contained few taxa from above ground tissues. Our data indicated compartmentalization of the microbiome with distinct profiles between above and below ground microbial communities. However, several taxa were present across all compartments suggesting the existence of a core citrus microbiota. These findings highlight key microbial taxa that could be engineered as biopesticides and biofertilizers for citriculture.
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Affiliation(s)
- MengYuan Xi
- Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, United States
| | - Elizabeth Deyett
- Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, United States
| | - Jason E Stajich
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA, United States
| | - Ashraf El-Kereamy
- Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, United States
| | - M Caroline Roper
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA, United States
| | - Philippe E Rolshausen
- Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, United States
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14
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Wang H, Mulgaonkar N, Mallawarachchi S, Ramasamy M, Padilla CS, Irigoyen S, Coaker G, Mandadi KK, Fernando S. Evaluation of Candidatus Liberibacter Asiaticus Efflux Pump Inhibition by Antimicrobial Peptides. Molecules 2022; 27:molecules27248729. [PMID: 36557860 PMCID: PMC9782701 DOI: 10.3390/molecules27248729] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/17/2022] [Accepted: 11/18/2022] [Indexed: 12/14/2022] Open
Abstract
Citrus greening, also known as Huanglongbing (HLB), is caused by the unculturable bacterium Candidatus Liberibacter spp. (e.g., CLas), and has caused a devastating decline in citrus production in many areas of the world. As of yet, there are no definitive treatments for controlling the disease. Antimicrobial peptides (AMPs) that have the potential to block secretion-dependent effector proteins at the outer-membrane domains were screened in silico. Predictions of drug-receptor interactions were built using multiple in silico techniques, including molecular docking analysis, molecular dynamics, molecular mechanics generalized Born surface area analysis, and principal component analysis. The efflux pump TolC of the Type 1 secretion system interacted with natural bacteriocin plantaricin JLA-9, blocking the β barrel. The trajectory-based principal component analysis revealed the possible binding mechanism of the peptides. Furthermore, in vitro assays using two closely related culturable surrogates of CLas (Liberibacter crescens and Rhizobium spp.) showed that Plantaricin JLA-9 and two other screened AMPs inhibited bacterial growth and caused mortality. The findings contribute to designing effective therapies to manage plant diseases associated with Candidatus Liberibacter spp.
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Affiliation(s)
- Haoqi Wang
- Biological and Agricultural Engineering Department, Texas A&M University, College Station, TX 77843, USA
| | - Nirmitee Mulgaonkar
- Biological and Agricultural Engineering Department, Texas A&M University, College Station, TX 77843, USA
| | - Samavath Mallawarachchi
- Biological and Agricultural Engineering Department, Texas A&M University, College Station, TX 77843, USA
| | - Manikandan Ramasamy
- Texas A&M AgriLife Research & Extension Center, Texas A&M University System, 2415 E. Highway 83, Weslaco, TX 78596, USA
| | - Carmen S. Padilla
- Texas A&M AgriLife Research & Extension Center, Texas A&M University System, 2415 E. Highway 83, Weslaco, TX 78596, USA
| | - Sonia Irigoyen
- Texas A&M AgriLife Research & Extension Center, Texas A&M University System, 2415 E. Highway 83, Weslaco, TX 78596, USA
| | - Gitta Coaker
- Department of Plant Pathology, University of California, Davis, CA 95616, USA
| | - Kranthi K. Mandadi
- Texas A&M AgriLife Research & Extension Center, Texas A&M University System, 2415 E. Highway 83, Weslaco, TX 78596, USA
- Department of Plant Pathology and Microbiology, Texas A&M University System, 2132 TAMU, College Station, TX 77843, USA
- Institute for Advancing Health through Agriculture, Texas A&M AgriLife, College Station, TX 77843, USA
- Correspondence: (K.K.M.); (S.F.)
| | - Sandun Fernando
- Biological and Agricultural Engineering Department, Texas A&M University, College Station, TX 77843, USA
- Correspondence: (K.K.M.); (S.F.)
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15
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Li J, He P, He P, Li Y, Wu Y, Lu Z, Li X, Yang Y, Wang Y, Guo J, Munir S, He Y. Potential of citrus endophyte Bacillus subtilis L1-21 in the control of Candidatus Liberibacter asiaticus in Asian citrus psyllid, Diaphorina citri. PEST MANAGEMENT SCIENCE 2022; 78:5164-5171. [PMID: 36114796 DOI: 10.1002/ps.7134] [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: 02/01/2022] [Revised: 08/08/2022] [Accepted: 08/18/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Asian citrus psyllid (ACP), also known as Diaphorina citri, is the natural vector of Candidatus Liberibacter asiaticus (CLas), which is responsible for Huanglongbing (HLB), a devastating citrus disease. Previously, the pathogen was successfully excluded from diseased citrus plants by using the indigenous endophyte Bacillus subtilis L1-21. However, the pathogen elimination and colonization potential of B. subtilis L1-21 in the carrier vector ACP, as well as the recruitment of native microbial communities of psyllid in the presence of endophytes, are still unknown. RESULTS Initially, we suggested that endophyte L1-21 reduced the CLas copies in ACP from 6.58 × 106 to 5.04 × 104 per insect after 48 h, however, the pathogen copies remained stable in the negative control. The endophyte was stable for 48 h after application. Among the bacterial genera those highlighted in ACP were Candidatus Liberibacter, Pseudomonas, Candidatus Profftella, Methylobacterium-Methylorubrum, Pantoea, Curtobacterium, Wolbachia, Actinomycetospora, and Bacillus. Interestingly, B. subtilis L1-21 easily colonizes the midgut of ACP but cannot be detected in eggs. When ACP with endophyte L1-21 was allowed to feed on new citrus leaves, the highest colonization was observed. We also found that psyllids carrying endophyte L1-21 after feeding on citrus leaves reduced the CLas copies in leaves on the 0, 3rd and 5th day from 8.18 × 10,4 2.6 × 10,3 and 0 pathogen copies/g fresh midvein, respectively. CONCLUSIONS We propose that B. subtilis L1-21 is a native endophyte in citrus and psyllid, which efficiently reduces the CLas pathogen in both citrus and psyllids, provides a more protective effect by increasing the number of cultivable endophytes, and successfully colonizes the midgut of ACP. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Jian Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Pengfei He
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Pengbo He
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Yongmei Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Yixin Wu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Zhanjun Lu
- College of Life Sciences, Gannan Normal University, Ganzhou, China
| | - Xingyu Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Yongchao Yang
- College of Biological and Agricultural Sciences, Honghe University, Mengzi, China
| | - Yuehu Wang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, China
| | - Jun Guo
- Institute of Tropical and Subtropical Cash Crops, Yunnan Academy of Agricultural Sciences, Baoshan, China
| | - Shahzad Munir
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Yueqiu He
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
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16
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Microbial Turnover and Dispersal Events Occur in Synchrony with Plant Phenology in the Perennial Evergreen Tree Crop Citrus sinensis. mBio 2022; 13:e0034322. [PMID: 35642946 PMCID: PMC9239260 DOI: 10.1128/mbio.00343-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Emerging research indicates that plant-associated microbes can alter plant developmental timing. However, it is unclear if host phenology affects microbial community assembly. Microbiome studies in annual or deciduous perennial plants face challenges in separating effects of tissue age from phenological driven effects on the microbiome. In contrast, evergreen perennial trees, like Citrus sinensis, retain leaves for years, allowing for uniform sampling of similarly aged leaves from the same developmental cohort. This aids in separating phenological effects on the microbiome from impacts due to annual leaf maturation/senescence. Here, we used this system to test the hypothesis that host phenology acts as a driver of microbiome composition. Citrus sinensis leaves and roots were sampled during seven phenological stages. Using amplicon-based sequencing, followed by diversity, phylogenetic, differential abundance, and network analyses, we examined changes in bacterial and fungal communities. Host phenological stage is the main determinant of microbiome composition, particularly within the foliar bacteriome. Microbial enrichment/depletion patterns suggest that microbial turnover and dispersal were driving these shifts. Moreover, a subset of community shifts were phylogenetically conserved across bacterial clades, suggesting that inherited traits contribute to microbe-microbe and/or plant-microbe interactions during specific phenophases. Plant phenology influences microbial community composition. These findings enhance understanding of microbiome assembly and identify microbes that potentially influence plant development and reproduction. IMPORTANCE Research at the forefront of plant microbiome studies indicates that plant-associated microbes can alter the timing of plant development (phenology). However, it is unclear if host phenological stage affects microbial community assembly. Microbiome studies in annual or deciduous perennial plants can face difficulty in separating effects of tissue age from phenological driven effects on the microbiome. Evergreen perennial plants, like sweet orange, maintain mature leaves for multiple years, allowing for uniform sampling of similarly aged tissue across host reproductive stages. Using this system, multiyear sampling, and high-throughput sequencing, we identified plant phenology as a major driver of microbiome composition, particularly within the leaf-associated bacterial communities. Distinct changes in microbial patterns suggest that microbial turnover and dispersal are mechanisms driving these community shifts. Additionally, closely related bacteria have similar abundance patterns across plant stages, indicating that inherited microbial traits may influence how bacteria respond to host developmental changes. Overall, this study illustrates that plant phenology does indeed govern microbiome seasonal shifts and identifies microbial candidates that may affect plant reproduction and development.
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17
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Penyalver R, Roesch LFW, Piquer-Salcedo JE, Forner-Giner MA, Alguacil MDM. From the bacterial citrus microbiome to the selection of potentially host-beneficial microbes. N Biotechnol 2022; 70:116-128. [PMID: 35717012 DOI: 10.1016/j.nbt.2022.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/09/2022] [Accepted: 06/11/2022] [Indexed: 10/18/2022]
Abstract
Citrus is the most cultivated fruit crop worldwide. The modern citrus industry needs new bioproducts to overcome phytopathological threats, tolerate stresses and increase yield and quality. Mutualistic microbes from roots significantly impact host physiology and health and are a potentially beneficial resource. The bacterial microbiome can be surveyed to select potentially host-beneficial microbes. To achieve this goal, a prevalent "core-citrus" bacterial microbiome was obtained by picking those operational taxonomic units (OTUs) shared among samples within and across two Citrus rootstock genotypes grown in the same soil for more than 20 years. A sub-selection of main OTUs from the defined "core-citrus" microbiome was made based on abundance, host-enriched versus bulk soil, and rhizosphere-indicator species. In parallel, an extensive census of the cultivable microbiota was performed to collect a large number of bacterial citrus isolates. Metataxonomic data were linked to cultured microbes, matching 16S rRNA gene sequences from bacterial isolates with those counterpart OTU reference sequences from the selected bacterial "core-citrus" microbiome. This approach allowed selection of potentially host-beneficial bacteria to mine for agricultural probiotics in future biotechnological applications required for the citrus industry.
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Affiliation(s)
- Ramón Penyalver
- Centre for Plant Protection and Biotechnology from Valencian Institute of Agricultural Sciences (IVIA), Moncada, València, Spain.
| | - Luiz F W Roesch
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, FL, USA
| | - Jaime E Piquer-Salcedo
- Centre for Plant Protection and Biotechnology from Valencian Institute of Agricultural Sciences (IVIA), Moncada, València, Spain
| | - María A Forner-Giner
- Centre for Citriculture and Plant Production from Valencian Institute of Agricultural Sciences (IVIA), Moncada, València, Spain
| | - María Del M Alguacil
- Center for Edaphology and Applied Biology of Segura (CEBAS) from Spanish Council for Scientific Research (CSIC) Agency, Murcia, Spain
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18
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Srivastava AK, Das AK, Jagannadham PTK, Bora P, Ansari FA, Bhate R. Bioprospecting Microbiome for Soil and Plant Health Management Amidst Huanglongbing Threat in Citrus: A Review. FRONTIERS IN PLANT SCIENCE 2022; 13:858842. [PMID: 35557712 PMCID: PMC9088001 DOI: 10.3389/fpls.2022.858842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 03/21/2022] [Indexed: 06/15/2023]
Abstract
Microorganisms have dynamic and complex interactions with their hosts. Diverse microbial communities residing near, on, and within the plants, called phytobiome, are an essential part of plant health and productivity. Exploiting citrus-associated microbiomes represents a scientific approach toward sustained and environment-friendly module of citrus production, though periodically exposed to several threats, with Huanglongbing (HLB) predominantly being most influential. Exploring the composition and function of the citrus microbiome, and possible microbial redesigning under HLB disease pressure has sparked renewed interest in recent times. A concise account of various achievements in understanding the citrus-associated microbiome, in various niche environments viz., rhizosphere, phyllosphere, endosphere, and core microbiota alongside their functional attributes has been thoroughly reviewed and presented. Efforts were also made to analyze the actual role of the citrus microbiome in soil fertility and resilience, interaction with and suppression of invading pathogens along with native microbial communities and their consequences thereupon. Despite the desired potential of the citrus microbiota to counter different pathogenic diseases, utilizing the citrus microbiome for beneficial applications at the field level is yet to be translated as a commercial product. We anticipate that advancement in multiomics technologies, high-throughput sequencing and culturing, genome editing tools, artificial intelligence, and microbial consortia will provide some exciting avenues for citrus microbiome research and microbial manipulation to improve the health and productivity of citrus plants.
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Affiliation(s)
- Anoop Kumar Srivastava
- Indian Council of Agricultural Research (ICAR)-Central Citrus Research Institute, Nagpur, India
| | - Ashis Kumar Das
- Indian Council of Agricultural Research (ICAR)-Central Citrus Research Institute, Nagpur, India
| | | | - Popy Bora
- Department of Plant Pathology, Assam Agricultural University, Jorhat, India
| | - Firoz Ahmad Ansari
- Indian Council of Agricultural Research (ICAR)-Central Citrus Research Institute, Nagpur, India
| | - Ruchi Bhate
- Indian Council of Agricultural Research (ICAR)-Central Citrus Research Institute, Nagpur, India
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19
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Witzell J, Decker VHG, Agostinelli M, Romeralo C, Cleary M, Albrectsen BR. Aspen Leaves as a "Chemical Landscape" for Fungal Endophyte Diversity-Effects of Nitrogen Addition. Front Microbiol 2022; 13:846208. [PMID: 35387081 PMCID: PMC8978019 DOI: 10.3389/fmicb.2022.846208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 01/19/2022] [Indexed: 11/16/2022] Open
Abstract
Abiotic and biotic factors may shape the mycobiome communities in plants directly but also indirectly by modifying the quality of host plants as a substrate. We hypothesized that nitrogen fertilization (N) would determine the quality of aspen (Populus tremula) leaves as a substrate for the endophytic fungi, and that by subjecting the plants to N, we could manipulate the concentrations of positive (nutritious) and negative (antifungal) chemicals in leaves, thus changing the internal “chemical landscape” for the fungi. We expected that this would lead to changes in the fungal community composition, in line with the predictions of heterogeneity–diversity relationship and resource availability hypotheses. To test this, we conducted a greenhouse study where aspen plants were subjected to N treatment. The chemical status of the leaves was confirmed using GC/MS (114 metabolites, including amino acids and sugars), LC/MS (11 phenolics), and UV-spectrometry (antifungal condensed tannins, CTs), and the endophytic communities were characterized using culture-dependent sequencing. We found that N treatment reduced foliar concentrations of CT precursor catechin but not that of CTs. Nitrogen treatment also increased the concentrations of the amino acids and reduced the concentration of some sugars. We introduced beetle herbivores (H) as a second treatment but found no rapid changes in chemical traits nor strong effect on the diversity of endophytes induced by herbivores. A few rare fungi were associated with and potentially vectored by the beetle herbivores. Our findings indicate that in a controlled environment, the externally induced changes did not strongly alter endophyte diversity in aspen leaves.
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Affiliation(s)
- Johanna Witzell
- Forestry and Wood Technology, Linnaeus University, Växjö, Sweden.,Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Vicki Huizu Guo Decker
- Department of Plant Physiology, Umeå Plant Science Center, Umeå University, Umeå, Sweden
| | - Marta Agostinelli
- Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Carmen Romeralo
- Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Alnarp, Sweden.,Forest Research Centre (INIA, CSIC), Madrid, Spain
| | - Michelle Cleary
- Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Alnarp, Sweden
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20
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De Francesco A, Lovelace AH, Shaw D, Qiu M, Wang Y, Gurung F, Ancona V, Wang C, Levy A, Jiang T, Ma W. Transcriptome Profiling of ' Candidatus Liberibacter asiaticus' in Citrus and Psyllids. PHYTOPATHOLOGY 2022; 112:116-130. [PMID: 35025694 DOI: 10.1094/phyto-08-21-0327-fi] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
'Candidatus Liberibacter asiaticus' (Las) is an emergent bacterial pathogen that is associated with the devastating citrus huanglongbing (HLB). Vectored by the Asian citrus psyllid, Las colonizes the phloem tissue of citrus, causing severe damage to infected trees. So far, cultivating pure Las culture in axenic media has not been successful, and dual-transcriptome analyses aiming to profile gene expression in both Las and its hosts have a low coverage of the Las genome because of the low abundance of bacterial RNA in total RNA extracts from infected tissues. Therefore, a lack of understanding of the Las transcriptome remains a significant knowledge gap. Here, we used a bacterial cell enrichment procedure and confidently determined the expression profiles of approximately 84% of the Las genes. Genes that exhibited high expression in citrus include transporters, ferritin, outer membrane porins, specific pilins, and genes involved in phage-related functions, cell wall modification, and stress responses. We also found 106 genes to be differentially expressed in citrus versus Asian citrus psyllids. Genes related to transcription or translation and resilience to host defense response were upregulated in citrus, whereas genes involved in energy generation and the flagella system were expressed to higher levels in psyllids. Finally, we determined the relative expression levels of potential Sec-dependent effectors, which are considered as key virulence factors of Las. This work advances our understanding of HLB biology and offers novel insight into the interactions of Las with its plant host and insect vector.
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Affiliation(s)
- Agustina De Francesco
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521, U.S.A
| | - Amelia H Lovelace
- The Sainsbury Laboratory, Norwich Research Park, NR4 7UH, United Kingdom
| | - Dipan Shaw
- Department of Computer Science and Engineering, University of California, Riverside, CA 92521, U.S.A
| | - Min Qiu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yuanchao Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Fatta Gurung
- Citrus Center, Department of Agriculture, Agribusiness and Environmental Sciences, Texas A&M University-Kingsville, Weslaco, TX 78599, U.S.A
| | - Veronica Ancona
- Citrus Center, Department of Agriculture, Agribusiness and Environmental Sciences, Texas A&M University-Kingsville, Weslaco, TX 78599, U.S.A
| | - Chunxia Wang
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, U.S.A
| | - Amit Levy
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, U.S.A
| | - Tao Jiang
- Department of Computer Science and Engineering, University of California, Riverside, CA 92521, U.S.A
| | - Wenbo Ma
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521, U.S.A
- The Sainsbury Laboratory, Norwich Research Park, NR4 7UH, United Kingdom
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21
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Huang J, Dai Z, Zheng Z, da Silvia PA, Kumagai L, Xiang Q, Chen J, Deng X. Bacteriomic Analyses of Asian Citrus Psyllid and Citrus Samples Infected With " Candidatus Liberibacter asiaticus" in Southern California and Huanglongbing Management Implications. Front Microbiol 2021; 12:683481. [PMID: 34276617 PMCID: PMC8283493 DOI: 10.3389/fmicb.2021.683481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 05/17/2021] [Indexed: 11/13/2022] Open
Abstract
Citrus Huanglongbing (HLB; yellow shoot disease) is associated with an unculturable α-proteobacterium "Candidatus Liberibacter asiaticus" (CLas). HLB was found in southern California in 2012, and the current management strategy is based on suppression of the Asian citrus psyllid (Diaphorina citri) that transmits CLas and removal of confirmed CLas-positive trees. Little is known about Asian citrus psyllid-associated bacteria and citrus-associated bacteria in the HLB system. Such information is important in HLB management, particularly for accurate detection of CLas. Recent advancements in next-generation sequencing technology provide new opportunities to study HLB through genomic DNA sequence analyses (metagenomics). In this study, HLB-related bacteria in Asian citrus psyllid and citrus (represented by leaf midrib tissues) samples from southern California were analyzed. A metagenomic pipeline was developed to serve as a prototype for future bacteriomic research. This pipeline included steps of next-generation sequencing in Illumina platform, de novo assembly of Illumina reads, sequence classification using the Kaiju tool, acquisition of bacterial draft genome sequences, and taxonomic validation and diversity evaluation using average nucleotide identity. The identified bacteria in Asian citrus psyllids and citrus together included Bradyrhizobium, Buchnera, Burkholderia, "Candidatus Profftella armature," "Candidatus Carsonella ruddii," CLas, Mesorhizobium, Paraburkholderia, Pseudomonas, and Wolbachia. The whole genome of a CLas strain recently found in San Bernardino County was sequenced and classified into prophage typing group 1 (PTG-1), one of the five known CLas groups in California. Based on sequence similarity, Bradyrhizobium and Mesorhizobium were identified as possible source that could interfere with CLas detection using the 16S rRNA gene-based PCR commonly used for HLB diagnosis, particularly at low or zero CLas titer situation.
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Affiliation(s)
- Jiaquan Huang
- Laboratory of Citrus Huanglongbing Research, College of Plant Protection, South China Agricultural University, Guangzhou, China
- San Joaquin Valley Agricultural Sciences Center, Agricultural Research Service, United States Department of Agriculture, Parlier, CA, United States
| | - Zehan Dai
- Laboratory of Citrus Huanglongbing Research, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Zheng Zheng
- Laboratory of Citrus Huanglongbing Research, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | | | - Luci Kumagai
- Plant Pest Diagnostic Center, California Department of Food and Agriculture, Sacramento, CA, United States
| | - Qijun Xiang
- Jerry Dimitman Laboratory, Riverside, CA, United States
| | - Jianchi Chen
- San Joaquin Valley Agricultural Sciences Center, Agricultural Research Service, United States Department of Agriculture, Parlier, CA, United States
| | - Xiaoling Deng
- Laboratory of Citrus Huanglongbing Research, College of Plant Protection, South China Agricultural University, Guangzhou, China
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22
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Munir S, Li Y, He P, He P, He P, Cui W, Wu Y, Li X, Li Q, Zhang S, Xiong Y, Lu Z, Wang W, Zong K, Yang Y, Yang S, Mu C, Wen H, Wang Y, Guo J, Karunarathna SC, He Y. Defeating Huanglongbing Pathogen Candidatus Liberibacter asiaticus With Indigenous Citrus Endophyte Bacillus subtilis L1-21. FRONTIERS IN PLANT SCIENCE 2021; 12:789065. [PMID: 35126416 PMCID: PMC8813962 DOI: 10.3389/fpls.2021.789065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 11/26/2021] [Indexed: 05/11/2023]
Abstract
Huanglongbing (HLB) has turned into a devastating botanical pandemic of citrus crops, caused by Candidatus Liberibacter asiaticus (CLas). However, until now the disease has remained incurable with very limited control strategies available. Restoration of the affected microbiomes in the diseased host through the introduction of an indigenous endophyte Bacillus subtilis L1-21 isolated from healthy citrus may provide an innovative approach for disease management. A novel half-leaf method was developed in vitro to test the efficacy of the endophyte L1-21 against CLas. Application of B. subtilis L1-21 at 104 colony forming unit (cfu ml-1) resulted in a 1,000-fold reduction in the CLas copies per gram of leaf midrib (107 to 104) in 4 days. In HLB-affected citrus orchards over a period of 2 years, the CLas incidence was reduced to < 3%, and CLas copies declined from 109 to 104 g-1 of diseased leaf midribs in the endophyte L1-21 treated trees. Reduction in disease incidence may corroborate a direct or an indirect biocontrol effect of the endophytes as red fluorescent protein-labeled B. subtilis L1-21 colonized and shared niche (phloem) with CLas. This is the first large-scale study for establishing a sustainable HLB control strategy through citrus endophytic microbiome restructuring using an indigenous endophyte.
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Affiliation(s)
- Shahzad Munir
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Yongmei Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Pengbo He
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Pengfei He
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Pengjie He
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Wenyan Cui
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Yixin Wu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Xingyu Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Qi Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Sixiang Zhang
- Binchuan Institute for Food and Medicine Inspection and Testing, Binchuan, China
| | - Yangsu Xiong
- Binchuan Institute for Food and Medicine Inspection and Testing, Binchuan, China
| | - Zhanjun Lu
- College of Life Sciences, Gannan Normal University, Ganzhou, China
| | - Wenbiao Wang
- Binchuan Institute for Food and Medicine Inspection and Testing, Binchuan, China
| | - Kexian Zong
- Binchuan Institute for Food and Medicine Inspection and Testing, Binchuan, China
| | - Yongchao Yang
- Institute of Upland Crops, Wenshan Academy of Agricultural Sciences, Wenshan, China
| | - Shaocong Yang
- Institute of Crop Fertilization, Yuxi Academy of Agricultural Sciences, Yuxi, China
| | - Chan Mu
- Institute of Crop Fertilization, Yuxi Academy of Agricultural Sciences, Yuxi, China
| | - Heming Wen
- Institute of Upland Crops, Wenshan Academy of Agricultural Sciences, Wenshan, China
| | - Yuehu Wang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, China
| | - Jun Guo
- Institute of Tropical and Subtropical Cash Crops, Yunnan Academy of Agricultural Sciences, Baoshan, China
| | - Samantha C. Karunarathna
- Center for Mountain Futures (CMF), Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, China
| | - Yueqiu He
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
- *Correspondence: Yueqiu He
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23
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Pagliaccia D, Bodaghi S, Chen X, Stevenson D, Deyett E, De Francesco A, Borneman J, Ruegger P, Peacock B, Ellstrand N, Rolshausen PE, Popa R, Ying S, Vidalakis G. Two Food Waste By-Products Selectively Stimulate Beneficial Resident Citrus Host-Associated Microbes in a Zero-Runoff Indoor Plant Production System. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2020. [DOI: 10.3389/fsufs.2020.593568] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The global production of food waste is a far-reaching problem with sizable financial, ethical, social, and environmental costs. Over 66 million tons of food waste is produced annually in the United States alone. This waste can be converted into valuable digestate by-products that promote a circular economy within agri-food systems. The present work investigated the use of two liquid digestates of microaerobic fermentation from mixed food waste and beer mash, respectively, as biostimulants for non-bearing citrus plants (nursery stock) grown in a zero-runoff greenhouse system with recirculating irrigation. The digestates' impact on the structure and diversity of the microbiota was determined on the irrigation water, soil, leaves, roots, and rhizosphere of citrus plants. A combination of culture-dependent (selective media) and culture-independent approaches (Next-Generation Sequencing) was used to assess the composition of the microbial communities and to single out the presence of foodborne pathogens. Our results suggest that the use of digestates is safe (i.e., no human or plant pathogens were present in the digestates or enriched in the plant production system following amendments). Digestates application to the irrigation water reduced the bacterial diversity within 24–48 h and selectively and significantly stimulated beneficial resident host-associated microorganisms (Pseudomonas putida) by two to three orders of magnitude. Carbon dynamics were analyzed in the nutrient solutions by measuring dissolved organic carbon and characterizing carbon species through gas chromatography-electron ionization-mass spectrometry. Our results indicate that dissolved organic carbon in the recirculating irrigation water spikes after each digestate amendment and it is quickly metabolized by bacteria, plateauing 24 h after application. Soil carbon, nitrogen, and nutrient dynamics were also analyzed, and results suggest that digestates increased the concentration of some plant nutrients in soils without causing a surge of potentially toxic elements. This study represents a proof-of-concept for the safe re-use of organic wastes, from farming and consumers, in agriculture. Implementing this type of integrated plant production system could reduce the environmental impact of food waste and benefit the public by improving soil health, reducing agricultural footprint, and increasing crop fitness by deploying a method based on a circular economy and sustainable food production approaches.
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24
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Brandenburg CA, Castro CA, Blacutt AA, Costa EA, Brinton KC, Corral DW, Drozd CL, Roper MC, Rolshausen PE, Maloney KN, Lockner JW. Synthesis of Deoxyradicinin, an Inhibitor of Xylella fastidiosa and Liberibacter crescens, a Culturable Surrogate for Candidatus Liberibacter asiaticus. JOURNAL OF NATURAL PRODUCTS 2020; 83:1810-1816. [PMID: 32510948 DOI: 10.1021/acs.jnatprod.9b01207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Pierce's disease of grapevine and citrus huanglongbing are caused by the bacterial pathogens Xylella fastidiosa and Candidatus Liberibacter asiaticus (CLas), respectively. Both pathogens reside within the plant vascular system, occluding water and nutrient transport, leading to a decrease in productivity and fruit marketability and ultimately death of their hosts. Field observations of apparently healthy plants in disease-affected vineyards and groves led to the hypothesis that natural products from endophytes may inhibit these bacterial pathogens. Previously, we showed that the natural product radicinin from Cochliobolus sp. inhibits X. fastidiosa. Herein we describe a chemical synthesis of deoxyradicinin and establish it as an inhibitor of both X. fastidiosa and Liberibacter crescens, a culturable surrogate for CLas. The key to this three-step route is a zinc-mediated enolate C-acylation, which allows for direct introduction of the propenyl side chain without extraneous redox manipulations.
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Affiliation(s)
- Connor A Brandenburg
- Department of Chemistry, Point Loma Nazarene University, San Diego, California 92106, United States
| | - Claudia A Castro
- Department of Microbiology and Plant Pathology, University of California, Riverside, California 92521, United States
| | - Alex A Blacutt
- Department of Microbiology and Plant Pathology, University of California, Riverside, California 92521, United States
| | | | - Kyler C Brinton
- Department of Chemistry, Point Loma Nazarene University, San Diego, California 92106, United States
| | - Diana W Corral
- Department of Chemistry, Point Loma Nazarene University, San Diego, California 92106, United States
| | - Christopher L Drozd
- Department of Microbiology and Plant Pathology, University of California, Riverside, California 92521, United States
| | - M Caroline Roper
- Department of Microbiology and Plant Pathology, University of California, Riverside, California 92521, United States
| | - Philippe E Rolshausen
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521, United States
| | - Katherine N Maloney
- Department of Chemistry, Point Loma Nazarene University, San Diego, California 92106, United States
| | - Jonathan W Lockner
- Department of Chemistry, Point Loma Nazarene University, San Diego, California 92106, United States
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