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Ramnarine SDB, Ali O, Jayaraman J, Ramsubhag A. Early transcriptional changes of heavy metal resistance and multiple efflux genes in Xanthomonas campestris pv. campestris under copper and heavy metal ion stress. BMC Microbiol 2024; 24:81. [PMID: 38461228 PMCID: PMC10924375 DOI: 10.1186/s12866-024-03206-7] [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: 01/10/2023] [Accepted: 01/28/2024] [Indexed: 03/11/2024] Open
Abstract
BACKGROUND Copper-induced gene expression in Xanthomonas campestris pv. campestris (Xcc) is typically evaluated using targeted approaches involving qPCR. The global response to copper stress in Xcc and resistance to metal induced damage is not well understood. However, homologs of heavy metal efflux genes from the related Stenotrophomonas genus are found in Xanthomonas which suggests that metal related efflux may also be present. METHODS AND RESULTS Gene expression in Xcc strain BrA1 exposed to 0.8 mM CuSO4.5H2O for 15 minutes was captured using RNA-seq analysis. Changes in expression was noted for genes related to general stress responses and oxidoreductases, biofilm formation, protein folding chaperones, heat-shock proteins, membrane lipid profile, multiple drug and efflux (MDR) transporters, and DNA repair were documented. At this timepoint only the cohL (copper homeostasis/tolerance) gene was upregulated as well as a chromosomal czcCBA efflux operon. An additional screen up to 4 hrs using qPCR was conducted using a wider range of heavy metals. Target genes included a cop-containing heavy metal resistance island and putative metal efflux genes. Several efflux pumps, including a copper resistance associated homolog from S. maltophilia, were upregulated under toxic copper stress. However, these pumps were also upregulated in response to other toxic heavy metals. Additionally, the temporal expression of the coh and cop operons was also observed, demonstrating co-expression of tolerance responses and later activation of part of the cop operon. CONCLUSIONS Overall, initial transcriptional responses focused on combating oxidative stress, mitigating protein damage and potentially increasing resistance to heavy metals and other biocides. A putative copper responsive efflux gene and others which might play a role in broader heavy metal resistance were also identified. Furthermore, the expression patterns of the cop operon in conjunction with other copper responsive genes allowed for a better understanding of the fate of copper ions in Xanthomonas. This work provides useful evidence for further evaluating MDR and other efflux pumps in metal-specific homeostasis and tolerance phenotypes in the Xanthomonas genus. Furthermore, non-canonical copper tolerance and resistance efflux pumps were potentially identified. These findings have implications for interpreting MIC differences among strains with homologous copLAB resistance genes, understanding survival under copper stress, and resistance in disease management.
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Affiliation(s)
- Stephen D B Ramnarine
- Department of Life Sciences, Faculty of Science and Technology, The University of The West Indies, St. Augustine campus, St. Augustine, Trinidad and Tobago, W. I
| | - Omar Ali
- Department of Life Sciences, Faculty of Science and Technology, The University of The West Indies, St. Augustine campus, St. Augustine, Trinidad and Tobago, W. I
| | - Jayaraj Jayaraman
- Department of Life Sciences, Faculty of Science and Technology, The University of The West Indies, St. Augustine campus, St. Augustine, Trinidad and Tobago, W. I
| | - Adesh Ramsubhag
- Department of Life Sciences, Faculty of Science and Technology, The University of The West Indies, St. Augustine campus, St. Augustine, Trinidad and Tobago, W. I.
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Qiu Y, Wei F, Meng H, Peng M, Zhang J, He Y, Wei L, Ahmed W, Ji G. Whole-genome sequencing and comparative genome analysis of Xanthomonas fragariae YM2 causing angular leaf spot disease in strawberry. FRONTIERS IN PLANT SCIENCE 2023; 14:1267132. [PMID: 38192696 PMCID: PMC10773614 DOI: 10.3389/fpls.2023.1267132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 11/27/2023] [Indexed: 01/10/2024]
Abstract
Background Angular leaf spot disease caused by plant pathogenic bacterium Xanthomonas fragariae seriously threatens strawberry crop production globally. Methods In this study, we sequenced the whole genome of X. fragariae YM2, isolated from Yunnan Province, China. In addition, we performed a comparative genome analysis of X. fragariae YM2 with two existing strains of X. fragariae YL19 and SHQP01 isolated from Liaoning and Shanghai, respectively. Results The results of Nanopore sequencing showed that X. fragariae YM2 comprises one single chromosome with a contig size of 4,263,697 bp, one plasmid contig size of 0.39 Mb, a GC content ratio of 62.27%, and 3,958 predicted coding genes. The genome of YM2 comprises gum, hrp, rpf, and xps gene clusters and lipopolysaccharide (LPS), which are typical virulence factors in Xanthomonas species. By performing a comparative genomic analysis between X. fragariae strains YM2, YL19, and SHQP01, we found that strain YM2 is similar to YL19 and SHQP01 regarding genome size and GC contents. However, there are minor differences in the composition of major virulence factors and homologous gene clusters. Furthermore, the results of collinearity analysis demonstrated that YM2 has lower similarity and longer evolutionary distance with YL19 and SHQP01, but YL19 is more closely related to SHQP01. Conclusions The availability of this high-quality genetic resource will serve as a basic tool for investigating the biology, molecular pathogenesis, and virulence of X. fragariae YM2. In addition, unraveling the potential vulnerabilities in its genetic makeup will aid in developing more effective disease suppression control measures.
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Affiliation(s)
- Yue Qiu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
- College of Agriculture, Anshun University, Anshun, Guizhou, China
- Key Laboratory of Agro-Biodiversity and Pest Management of Ministry of Education, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Fangjun Wei
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
- Key Laboratory of Agro-Biodiversity and Pest Management of Ministry of Education, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Han Meng
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
- Key Laboratory of Agro-Biodiversity and Pest Management of Ministry of Education, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Menglin Peng
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
- Key Laboratory of Agro-Biodiversity and Pest Management of Ministry of Education, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Jinhao Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
- Key Laboratory of Agro-Biodiversity and Pest Management of Ministry of Education, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Yilu He
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
- Key Laboratory of Agro-Biodiversity and Pest Management of Ministry of Education, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Lanfang Wei
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
- Agricultural Foundation Experiment Teaching Center, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Waqar Ahmed
- College of Plant Protection, South China Agricultural University, Guangzhou, Guangdong, China
| | - Guanghai Ji
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
- Key Laboratory of Agro-Biodiversity and Pest Management of Ministry of Education, Yunnan Agricultural University, Kunming, Yunnan, China
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Schüroff PA, Abe CM, Silva JW, de Paula Coelho C, Andrade FB, Hernandes RT, Dobrindt U, Gomes TAT, Elias WP. Role of aggregate-forming pilus (AFP) in adherence and colonization of both intestinal and urinary tracts. Virulence 2022; 13:1423-1433. [PMID: 35982607 PMCID: PMC9397481 DOI: 10.1080/21505594.2022.2112818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hybrid-pathogenic Escherichia coli represent an important group of strains associated with intestinal and extraintestinal infections. Recently, we described strain UPEC-46, a uropathogenic/enteroaggregative E. coli (UPEC/EAEC) strain presenting the aggregative adherence (AA) pattern on bladder and colorectal epithelial cells mediated by aggregate-forming pili (AFP). However, the role of AFP and other uninvestigated putative fimbriae operons in UPEC-46 pathogenesis remains unclear. Thus, this study evaluated the involvement of AFP and other adhesins in uropathogenicity and intestinal colonization using different in vitro and in vivo models. The strain UPEC-46 was able to adhere and invade intestinal and urinary cell lines. A library of transposon mutants also identified the involvement of type I fimbriae (TIF) in the adherence to HeLa cells, in addition to colorectal and bladder cell lines. The streptomycin-treated mouse in vivo model also showed an increased number of bacterial counts in the colon in the presence of AFP and TIF. In the mouse model of ascending urinary tract infection (UTI), AFP was more associated with kidney colonization, while TIF appears to mediate bladder colonization. Results observed in in vivo experiments were also confirmed by electron microscopy (EM) analyses. In summary, the in vitro and in vivo analyses show a synergistic role of AFP and TIF in the adherence and colonization of intestinal and urinary epithelia. Therefore, we propose that hybrid E. coli strains carrying AFP and TIF could potentially cause intestinal and urinary tract infections in the same patient.
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Affiliation(s)
- Paulo A Schüroff
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil.,Institute of Hygiene, University of Münster, Münster, Germany
| | - Cecilia M Abe
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | - Jonatas W Silva
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | - Cidéli de Paula Coelho
- Departamento de Pós-graduação, Faculdade de Medicina Veterinária, Universidade Santo Amaro, São Paulo, Brazil
| | | | - Rodrigo T Hernandes
- Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, Brazil
| | - Ulrich Dobrindt
- Institute of Hygiene, University of Münster, Münster, Germany
| | - Tânia A T Gomes
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Waldir P Elias
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
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Toushik SH, Roy A, Alam M, Rahman UH, Nath NK, Nahar S, Matubber B, Uddin MJ, Roy PK. Pernicious Attitude of Microbial Biofilms in Agri-Farm Industries: Acquisitions and Challenges of Existing Antibiofilm Approaches. Microorganisms 2022; 10:microorganisms10122348. [PMID: 36557600 PMCID: PMC9781080 DOI: 10.3390/microorganisms10122348] [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: 11/10/2022] [Revised: 11/22/2022] [Accepted: 11/24/2022] [Indexed: 11/29/2022] Open
Abstract
Biofilm is a complex matrix made up of extracellular polysaccharides, DNA, and proteins that protect bacteria against physical, chemical, and biological stresses and allow them to survive in harsh environments. Safe and healthy foods are mandatory for saving lives. However, foods can be contaminated by pathogenic microorganisms at any stage from farm to fork. The contaminated foods allow pathogenic microorganisms to form biofilms and convert the foods into stigmatized poison for consumers. Biofilm formation by pathogenic microorganisms in agri-farm industries is still poorly understood and intricate to control. In biofilms, pathogenic bacteria are dwelling in a complex manner and share their genetic and physicochemical properties making them resistant to common antimicrobial agents. Therefore, finding the appropriate antibiofilm approaches is necessary to inhibit and eradicate the mature biofilms from foods and food processing surfaces. Advanced studies have already established several emerging antibiofilm approaches including plant- and microbe-derived biological agents, and they proved their efficacy against a broad-spectrum of foodborne pathogens. This review investigates the pathogenic biofilm-associated problems in agri-farm industries, potential remedies, and finding the solution to overcome the current challenges of antibiofilm approaches.
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Affiliation(s)
- Sazzad Hossen Toushik
- Institute for Smart Farm, Department of Food Hygiene and Safety, Gyeongsang National University, Jinju 52828, Republic of Korea
- ABEx Bio-Research Center, Azampur, Dakkhinkhan, Dhaka 1230, Bangladesh
| | - Anamika Roy
- ABEx Bio-Research Center, Azampur, Dakkhinkhan, Dhaka 1230, Bangladesh
| | - Mohaimanul Alam
- ABEx Bio-Research Center, Azampur, Dakkhinkhan, Dhaka 1230, Bangladesh
- Department of Biotechnology and Genetic Engineering, Noakhali Science and Technology University, Noakhali 3814, Bangladesh
| | - Umma Habiba Rahman
- ABEx Bio-Research Center, Azampur, Dakkhinkhan, Dhaka 1230, Bangladesh
- Department of Biotechnology and Genetic Engineering, Noakhali Science and Technology University, Noakhali 3814, Bangladesh
| | - Nikash Kanti Nath
- ABEx Bio-Research Center, Azampur, Dakkhinkhan, Dhaka 1230, Bangladesh
- Department of Biotechnology and Genetic Engineering, Mawlana Bhasani Science and Technology University, Tangail 1902, Bangladesh
| | - Shamsun Nahar
- ABEx Bio-Research Center, Azampur, Dakkhinkhan, Dhaka 1230, Bangladesh
| | - Bidyut Matubber
- ABEx Bio-Research Center, Azampur, Dakkhinkhan, Dhaka 1230, Bangladesh
- Department of Microbiology and Public Health, Khulna Agricultural University, Khulna 9100, Bangladesh
| | - Md Jamal Uddin
- ABEx Bio-Research Center, Azampur, Dakkhinkhan, Dhaka 1230, Bangladesh
| | - Pantu Kumar Roy
- ABEx Bio-Research Center, Azampur, Dakkhinkhan, Dhaka 1230, Bangladesh
- Institute of Marine Industry, Department of Seafood Science and Technology, Gyeongsang National University, Tongyeong 53064, Republic of Korea
- Correspondence: ; Tel.: +82-10-4649-9816; Fax: +82-0504-449-9816
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Long Y, Luo R, Xu Z, Cheng S, Li L, Ma H, Bao M, Li M, Ouyang Z, Wang N, Duan S. A Fluorescent Reporter-Based Evaluation Assay for Antibacterial Components Against Xanthomonas citri subsp. citri. Front Microbiol 2022; 13:864963. [PMID: 35602035 PMCID: PMC9114712 DOI: 10.3389/fmicb.2022.864963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 04/05/2022] [Indexed: 11/13/2022] Open
Abstract
Xanthomonas citri subsp. citri (Xcc) is the agent of citrus bacterial canker (CBC) disease, which has significantly reduced citrus quantity and quality in many producing areas worldwide. Copper-based bactericides are the primary products for CBC control and management, but the problems derived from copper-resistant and environmental contamination have become issues of anxiety. Thus, there is a need to find alternative antibacterial products instead of relying on a single type of agent. This study developed a method to evaluate the inhibition of antibacterial agents using the fluorescence-labeled recombinant Xcc strain (Xcc-eYFP). The optimization of timelines and parameters for the evaluation of antibacterial agents involved the use of a Spark™ multimode microplate reader. This evaluation and screening method can be applied to bactericides, cocktail-mixture formulations, antagonistic bacteria, and derived metabolites. The results showed that the minimum inhibitory concentration (MIC) of commercial bactericides determined by fluorescence agrees with the MIC values determined by the conventional method. A screened cocktail-mixture bactericide presents more activity than the individual agents during the protective effects. Notably, this method has been further developed in the screening of Xcc-antagonistic bacterial strains. In summary, we provide a validated strategy for screening and evaluation of different antibacterial components for inhibition against Xcc for CBC control and management.
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Affiliation(s)
- Yunfei Long
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Ruifang Luo
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Zhou Xu
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Shuyuan Cheng
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Ling Li
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Haijie Ma
- College of Agricultural and Food Sciences, Zhejiang A&F University, Hangzhou, China
| | - Minli Bao
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Min Li
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Zhigang Ouyang
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Nian Wang
- Department of Microbiology and Cell Science, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, United States
| | - Shuo Duan
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
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Duan S, Long Y, Cheng S, Li J, Ouyang Z, Wang N. Rapid Evaluation of the Resistance of Citrus Germplasms Against Xanthomonas citri subsp. citri. PHYTOPATHOLOGY 2022; 112:765-774. [PMID: 34495678 DOI: 10.1094/phyto-04-21-0175-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Xanthomonas citri subsp. citri (Xcc) is the causal agent of citrus bacterial canker (CBC), one of the most devastating citrus diseases. Most commercial citrus varieties are susceptible to CBC. However, some citrus varieties and wild citrus germplasms are CBC resistant and are promising in genetic increases in citrus resistance against CBC. We aimed to evaluate citrus germplasms for resistance against CBC. First, we developed a rapid evaluation method based on enhanced yellow fluorescent protein (eYFP)-labeled Xcc. The results demonstrated that eYFP does not affect the growth and virulence of Xcc. Xcc-eYFP allows measurement of bacterial titers but is more efficient and rapid than the plate colony counting method. Next, we evaluated citrus germplasms collected in China. Based on symptoms and bacterial titers, we identified that two citrus germplasms ('Ichang' papeda and 'Huapi' kumquat) are resistant, whereas eight citrus germplasms ('Chongyi' wild mandarin, 'Mangshan' wild mandarin, 'Ledong' kumquat, 'Dali' citron, 'Yiliang' citron, 'Longyan' kumquat, 'Bawang' kumquat, and 'Daoxian' wild mandarin) are tolerant. In summary, we have developed a rapid evaluation method to test the resistance of citrus plants against CBC. This method was successfully used to identify two highly canker-resistant citrus germplasms and eight citrus germplasms with canker tolerance. These results could be leveraged in traditional breeding contexts or be used to identify canker resistance genes to increase the disease resistance of commercial citrus varieties via biotechnological approaches.
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Affiliation(s)
- Shuo Duan
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi 341000, China
| | - Yunfei Long
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi 341000, China
| | - Shuyuan Cheng
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi 341000, China
| | - Jinyun Li
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL 33850, U.S.A
| | - Zhigang Ouyang
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi 341000, China
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL 33850, U.S.A
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Fan Q, Bibi S, Vallad GE, Goss EM, Hurlbert JC, Paret ML, Jones JB, Timilsina S. Identification of Genes in Xanthomonas euvesicatoria pv. rosa That Are Host Limiting in Tomato. PLANTS 2022; 11:plants11060796. [PMID: 35336678 PMCID: PMC8951399 DOI: 10.3390/plants11060796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/24/2022] [Accepted: 03/02/2022] [Indexed: 11/30/2022]
Abstract
Xanthomonas euvesicatoria pv. rosa strain Xer07 causes a leaf spot on a Rosa sp. and is closely related to X. euvesicatoria pv. euvesicatoria (Xee) and X. perforans (Xp), causal agents of bacterial spot of tomato. However, Xer07 is not pathogenic on tomato and elicits a hypersensitive reaction (HR). We compared the genomes of the three bacterial species to identify the factors that limit Xer07 on tomato. Comparison of pathogenicity associated factors including the type III secretion systems identified two genes, xopA and xer3856, in Xer07 that have lower sequence homology in tomato pathogens. xer3856 is a homolog of genes in X. citri (xac3856) and X. fuscans pv. aurantifolii, both of which have been reported to elicit HRs in tomato. When xer3856 was expressed in X. perforans and infiltrated in tomato leaflets, the transconjugant elicited an HR and significantly reduced bacterial populations compared to the wildtype X. perforans strain. When xer3856 was mutated in Xer07, the mutant strain still triggered an HR in tomato leaflets. The second gene identified codes for type III secreted effector XopA, which contains a harpin domain that is distinct from the xopA homologs in Xee and Xp. The Xer07-xopA, when expressed in X. perforans, did not elicit an HR in tomato leaflets, but significantly reduced bacterial populations. This indicates that xopA and xer3856 genes in combination with an additional factor(s) limit Xer07 in tomato.
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Affiliation(s)
- Qiurong Fan
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA; (Q.F.); (S.B.); (G.E.V.); (E.M.G.); (M.L.P.)
| | - Shaheen Bibi
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA; (Q.F.); (S.B.); (G.E.V.); (E.M.G.); (M.L.P.)
| | - Gary E. Vallad
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA; (Q.F.); (S.B.); (G.E.V.); (E.M.G.); (M.L.P.)
- Gulf Coast Research and Education Center, University of Florida, Balm, FL 33598, USA
| | - Erica M. Goss
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA; (Q.F.); (S.B.); (G.E.V.); (E.M.G.); (M.L.P.)
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32610, USA
| | - Jason C. Hurlbert
- Department of Chemistry, Physics and Geology, Winthrop University, Rock Hill, SC 29733, USA;
| | - Matthews L. Paret
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA; (Q.F.); (S.B.); (G.E.V.); (E.M.G.); (M.L.P.)
- North Florida Research and Education Center, University of Florida, Quincy, FL 32351, USA
| | - Jeffrey B. Jones
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA; (Q.F.); (S.B.); (G.E.V.); (E.M.G.); (M.L.P.)
- Correspondence: (J.B.J.); (S.T.)
| | - Sujan Timilsina
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA; (Q.F.); (S.B.); (G.E.V.); (E.M.G.); (M.L.P.)
- Correspondence: (J.B.J.); (S.T.)
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Lin M, Wu K, Zhan Z, Mi D, Xia Y, Niu X, Feng S, Chen Y, He C, Tao J, Li C. The RavA/VemR two-component system plays vital regulatory roles in the motility and virulence of Xanthomonas campestris. MOLECULAR PLANT PATHOLOGY 2022; 23:355-369. [PMID: 34837306 PMCID: PMC8828458 DOI: 10.1111/mpp.13164] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/26/2021] [Accepted: 10/26/2021] [Indexed: 05/08/2023]
Abstract
Xanthomonas campestris pv. campestris (Xcc) can cause black rot in cruciferous plants worldwide. Two-component systems (TCSs) are key for bacterial adaptation to various environments, including hosts. VemR is a TCS response regulator and crucial for Xcc motility and virulence. Here, we report that RavA is the cognate histidine kinase (HK) of VemR and elucidate the signalling pathway by which VemR regulates Xcc motility and virulence. Genetic analysis showed that VemR is epistatic to RavA. Using bacterial two-hybrid experiments and pull-down and phosphorylation assays, we found that RavA can interact with and phosphorylate VemR, suggesting that RavA is the cognate HK of VemR. In addition, we found that RpoN2 and FleQ are epistatic to VemR in regulating bacterial motility and virulence. In vivo and in vitro experiments demonstrated that VemR interacts with FleQ but not with RpoN2. RavA/VemR regulates the expression of the flagellin-encoding gene fliC by activating the transcription of the rpoN2-vemR-fleQ and flhF-fleN-fliA operons. In summary, our data show that the RavA/VemR TCS regulates FleQ activity and thus influences the expression of motility-related genes, thereby affecting Xcc motility and virulence. The identification of this novel signalling pathway will deepen our understanding of Xcc-plant interactions.
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Affiliation(s)
- Maojuan Lin
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Kejian Wu
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Zhaohong Zhan
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Duo Mi
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Yingying Xia
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Xiaolei Niu
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Shipeng Feng
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Yinhua Chen
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Chaozu He
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Jun Tao
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Chunxia Li
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
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Grigorian E, Groisillier A, Thomas F, Leblanc C, Delage L. Functional Characterization of a L-2-Haloacid Dehalogenase From Zobellia galactanivorans Dsij T Suggests a Role in Haloacetic Acid Catabolism and a Wide Distribution in Marine Environments. Front Microbiol 2021; 12:725997. [PMID: 34621253 PMCID: PMC8490876 DOI: 10.3389/fmicb.2021.725997] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/31/2021] [Indexed: 12/21/2022] Open
Abstract
L-2-halocid dehalogenases (L-2-HADs) have been mainly characterized from terrestrial polluted environments. By contrast, knowledge is still scarce about their role in detoxification of predominant halocarbons in marine environments. Here, phylogenetic analyses showed a wide diversity of homologous L-2-HADs, especially among those belonging to marine bacteria. Previously characterized terrestrial L-2-HADs were part of a monophyletic group (named group A) including proteins of terrestrial and marine origin. Another branch (named group B) contained mostly marine L-2-HADs, with two distinct clades of Bacteroidetes homologs, closely linked to Proteobacteria ones. This study further focused on the characterization of the only L-2-HAD from the flavobacterium Zobellia galactanivorans DsijT (ZgHAD), belonging to one of these Group B clades. The recombinant ZgHAD was shown to dehalogenate bromo- and iodoacetic acids, and gene knockout in Z. galactanivorans revealed a direct role of ZgHAD in tolerance against both haloacetic acids. Analyses of metagenomic and metatranscriptomic datasets confirmed that L-2-HADs from group A were well-represented in terrestrial and marine bacteria, whereas ZgHAD homologs (group B L-2-HADs) were mainly present in marine bacteria, and particularly in host-associated species. Our results suggest that ZgHAD homologs could be key enzymes for marine Bacteroidetes, by conferring selective advantage for the recycling of toxic halogen compounds produced in particular marine habitats, and especially during interactions with macroalgae.
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Affiliation(s)
- Eugénie Grigorian
- CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, Roscoff, France
| | - Agnès Groisillier
- CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, Roscoff, France
| | - François Thomas
- CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, Roscoff, France
| | - Catherine Leblanc
- CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, Roscoff, France
| | - Ludovic Delage
- CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, Roscoff, France
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10
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Teper D, Xu J, Pandey SS, Wang N. PthAW1, a Transcription Activator-Like Effector of Xanthomonas citri subsp. citri, Promotes Host-Specific Immune Responses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:1033-1047. [PMID: 33970668 DOI: 10.1094/mpmi-01-21-0026-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Citrus canker disease caused by Xanthomonas citri subsp. citri is one of the most destructive diseases in citrus. X. citri subsp. citri pathotypes display different host ranges. X. citri subsp. citri strain A (XccA) causes canker disease in most commercial citrus varieties, whereas strain AW (XccAW), which is genetically similar to XccA, infects only lime and alemow. Understanding the mechanism that determines the host range of pathogens is critical to investigating and utilizing host resistance. We hypothesized that XccAW would undergo mutations in genes that restrict its host range when artificially inoculated into incompatible citrus varieties. To test this hypothesis, we used an experimental evolution approach to identify phenotypic traits and genetic loci associated with the adaptation of XccAW to incompatible sweet orange. Repeated inoculation and reisolation cycles improved the ability of three independent XccAW strains to colonize sweet orange. Adapted XccAW strains displayed increased expression of type III secretion system and effector genes. Genome sequencing analysis indicated that two of the adapted strains harbored mutations in pthAW1, a transcription activator-like effector (TALE) gene, that corresponded to the removal of one or two repeats from the central DNA-binding repeat region. Introduction of the original but not the adapted pthAW1 variants into XccA abolished its ability to cause canker symptoms in sweet orange, Meyer lemon, and clementine but not in other XccAW-resistant citrus varieties. The original pthAW1, when expressed in XccA, induced ion leakage and the expression of pathogenesis-related genes but had no effect on CsLOB1 expression in sweet orange. Our study has identified a novel host-specific avirulence TALE and demonstrated active adaptive rearrangements of the TALE repeat array during host adaptation.[Formula: see text] Copyright © 2021 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)
- Doron Teper
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, U.S.A
| | - Jin Xu
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, U.S.A
| | - Sheo Shankar Pandey
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, U.S.A
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, U.S.A
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11
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Picchi SC, de Souza E Silva M, Saldanha LL, Ferreira H, Takita MA, Caldana C, de Souza AA. GC-TOF/MS-based metabolomics analysis to investigate the changes driven by N-Acetylcysteine in the plant-pathogen Xanthomonas citri subsp. citri. Sci Rep 2021; 11:15558. [PMID: 34330957 PMCID: PMC8324833 DOI: 10.1038/s41598-021-95113-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 07/09/2021] [Indexed: 11/09/2022] Open
Abstract
N-Acetylcysteine (NAC) is an antioxidant, anti-adhesive, and antimicrobial compound. Even though there is much information regarding the role of NAC as an antioxidant and anti-adhesive agent, little is known about its antimicrobial activity. In order to assess its mode of action in bacterial cells, we investigated the metabolic responses triggered by NAC at neutral pH. As a model organism, we chose the Gram-negative plant pathogen Xanthomonas citri subsp. citri (X. citri), the causal agent of citrus canker disease, due to the potential use of NAC as a sustainable molecule against phytopathogens dissemination in citrus cultivated areas. In presence of NAC, cell proliferation was affected after 4 h, but damages to the cell membrane were observed only after 24 h. Targeted metabolite profiling analysis using GC-MS/TOF unravelled that NAC seems to be metabolized by the cells affecting cysteine metabolism. Intriguingly, glutamine, a marker for nitrogen status, was not detected among the cells treated with NAC. The absence of glutamine was followed by a decrease in the levels of the majority of the proteinogenic amino acids, suggesting that the reduced availability of amino acids affect protein synthesis and consequently cell proliferation.
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Affiliation(s)
- Simone Cristina Picchi
- Centro de Citricultura "Sylvio Moreira" - Instituto Agronômico de Campinas, Cordeirópolis, São Paulo, 13490-970, Brazil
| | - Mariana de Souza E Silva
- Centro de Citricultura "Sylvio Moreira" - Instituto Agronômico de Campinas, Cordeirópolis, São Paulo, 13490-970, Brazil
| | - Luiz Leonardo Saldanha
- Departamento de Bioquímica e Microbiologia, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, São Paulo, 13506-900, Brazil
| | - Henrique Ferreira
- Departamento de Bioquímica e Microbiologia, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, São Paulo, 13506-900, Brazil
| | - Marco Aurélio Takita
- Centro de Citricultura "Sylvio Moreira" - Instituto Agronômico de Campinas, Cordeirópolis, São Paulo, 13490-970, Brazil
| | - Camila Caldana
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol - Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo, 13083-100, Brazil.,Max-Planck-Institut Für Molekulare Pflanzenphysiologie, Wissenschaftspark Golm, Am Mühlenberg 1, 14476, Potsdam, Germany
| | - Alessandra Alves de Souza
- Centro de Citricultura "Sylvio Moreira" - Instituto Agronômico de Campinas, Cordeirópolis, São Paulo, 13490-970, Brazil.
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12
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Identification of Three Type II Toxin-Antitoxin Systems in Model Bacterial Plant Pathogen Dickeya dadantii 3937. Int J Mol Sci 2021; 22:ijms22115932. [PMID: 34073004 PMCID: PMC8198452 DOI: 10.3390/ijms22115932] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 05/28/2021] [Accepted: 05/28/2021] [Indexed: 11/17/2022] Open
Abstract
Type II toxin-antitoxin (TA) systems are genetic elements usually encoding two proteins: a stable toxin and an antitoxin, which binds the toxin and neutralizes its toxic effect. The disturbance in the intracellular toxin and antitoxin ratio typically leads to inhibition of bacterial growth or bacterial cell death. Despite the fact that TA modules are widespread in bacteria and archaea, the biological role of these systems is ambiguous. Nevertheless, a number of studies suggests that the TA modules are engaged in such important processes as biofilm formation, stress response or virulence and maintenance of mobile genetic elements. The Dickeya dadantii 3937 strain serves as a model for pathogens causing the soft-rot disease in a wide range of angiosperm plants. Until now, several chromosome-encoded type II TA systems were identified in silico in the genome of this economically important bacterium, however so far only one of them was experimentally validated. In this study, we investigated three putative type II TA systems in D. dadantii 3937: ccdAB2Dda, phd-docDda and dhiTA, which represents a novel toxin/antitoxin superfamily. We provide an experimental proof for their functionality in vivo both in D. dadantii and Escherichia coli. Finally, we examined the prevalence of those systems across the Pectobacteriaceae family by a phylogenetic analysis.
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13
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Secrete or perish: The role of secretion systems in Xanthomonas biology. Comput Struct Biotechnol J 2020; 19:279-302. [PMID: 33425257 PMCID: PMC7777525 DOI: 10.1016/j.csbj.2020.12.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/13/2020] [Accepted: 12/13/2020] [Indexed: 12/22/2022] Open
Abstract
Bacteria of the Xanthomonas genus are mainly phytopathogens of a large variety of crops of economic importance worldwide. Xanthomonas spp. rely on an arsenal of protein effectors, toxins and adhesins to adapt to the environment, compete with other microorganisms and colonize plant hosts, often causing disease. These protein effectors are mainly delivered to their targets by the action of bacterial secretion systems, dedicated multiprotein complexes that translocate proteins to the extracellular environment or directly into eukaryotic and prokaryotic cells. Type I to type VI secretion systems have been identified in Xanthomonas genomes. Recent studies have unravelled the diverse roles played by the distinct types of secretion systems in adaptation and virulence in xanthomonads, unveiling new aspects of their biology. In addition, genome sequence information from a wide range of Xanthomonas species and pathovars have become available recently, uncovering a heterogeneous distribution of the distinct families of secretion systems within the genus. In this review, we describe the architecture and mode of action of bacterial type I to type VI secretion systems and the distribution and functions associated with these important nanoweapons within the Xanthomonas genus.
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14
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An SQ, Potnis N, Dow M, Vorhölter FJ, He YQ, Becker A, Teper D, Li Y, Wang N, Bleris L, Tang JL. Mechanistic insights into host adaptation, virulence and epidemiology of the phytopathogen Xanthomonas. FEMS Microbiol Rev 2020; 44:1-32. [PMID: 31578554 PMCID: PMC8042644 DOI: 10.1093/femsre/fuz024] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 09/29/2019] [Indexed: 01/15/2023] Open
Abstract
Xanthomonas is a well-studied genus of bacterial plant pathogens whose members cause a variety of diseases in economically important crops worldwide. Genomic and functional studies of these phytopathogens have provided significant understanding of microbial-host interactions, bacterial virulence and host adaptation mechanisms including microbial ecology and epidemiology. In addition, several strains of Xanthomonas are important as producers of the extracellular polysaccharide, xanthan, used in the food and pharmaceutical industries. This polymer has also been implicated in several phases of the bacterial disease cycle. In this review, we summarise the current knowledge on the infection strategies and regulatory networks controlling virulence and adaptation mechanisms from Xanthomonas species and discuss the novel opportunities that this body of work has provided for disease control and plant health.
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Affiliation(s)
- Shi-Qi An
- National Biofilms Innovation Centre (NBIC), Biological Sciences, University of Southampton, University Road, Southampton SO17 1BJ, UK
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Rouse Life Science Building, Auburn University, Auburn AL36849, USA
| | - Max Dow
- School of Microbiology, Food Science & Technology Building, University College Cork, Cork T12 K8AF, Ireland
| | | | - Yong-Qiang He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning 530004, Guangxi, China
| | - Anke Becker
- Loewe Center for Synthetic Microbiology and Department of Biology, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Doron Teper
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred 33850, USA
| | - Yi Li
- Bioengineering Department, University of Texas at Dallas, 2851 Rutford Ave, Richardson, TX 75080, USA.,Center for Systems Biology, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX 75080, USA
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred 33850, USA
| | - Leonidas Bleris
- Bioengineering Department, University of Texas at Dallas, 2851 Rutford Ave, Richardson, TX 75080, USA.,Center for Systems Biology, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX 75080, USA.,Department of Biological Sciences, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX75080, USA
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning 530004, Guangxi, China
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15
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Botero D, Monk J, Rodríguez Cubillos MJ, Rodríguez Cubillos A, Restrepo M, Bernal-Galeano V, Reyes A, González Barrios A, Palsson BØ, Restrepo S, Bernal A. Genome-Scale Metabolic Model of Xanthomonas phaseoli pv. manihotis: An Approach to Elucidate Pathogenicity at the Metabolic Level. Front Genet 2020; 11:837. [PMID: 32849823 PMCID: PMC7432306 DOI: 10.3389/fgene.2020.00837] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 07/10/2020] [Indexed: 01/05/2023] Open
Abstract
Xanthomonas phaseoli pv. manihotis (Xpm) is the causal agent of cassava bacterial blight, the most important bacterial disease in this crop. There is a paucity of knowledge about the metabolism of Xanthomonas and its relevance in the pathogenic process, with the exception of the elucidation of the xanthan biosynthesis route. Here we report the reconstruction of the genome-scale model of Xpm metabolism and the insights it provides into plant-pathogen interactions. The model, iXpm1556, displayed 1,556 reactions, 1,527 compounds, and 890 genes. Metabolic maps of central amino acid and carbohydrate metabolism, as well as xanthan biosynthesis of Xpm, were reconstructed using Escher (https://escher.github.io/) to guide the curation process and for further analyses. The model was constrained using the RNA-seq data of a mutant of Xpm for quorum sensing (QS), and these data were used to construct context-specific models (CSMs) of the metabolism of the two strains (wild type and QS mutant). The CSMs and flux balance analysis were used to get insights into pathogenicity, xanthan biosynthesis, and QS mechanisms. Between the CSMs, 653 reactions were shared; unique reactions belong to purine, pyrimidine, and amino acid metabolism. Alternative objective functions were used to demonstrate a trade-off between xanthan biosynthesis and growth and the re-allocation of resources in the process of biosynthesis. Important features altered by QS included carbohydrate metabolism, NAD(P)+ balance, and fatty acid elongation. In this work, we modeled the xanthan biosynthesis and the QS process and their impact on the metabolism of the bacterium. This model will be useful for researchers studying host-pathogen interactions and will provide insights into the mechanisms of infection used by this and other Xanthomonas species.
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Affiliation(s)
- David Botero
- Laboratory of Mycology and Plant Pathology (LAMFU), Department of Chemical and Food Engineering, Universidad de Los Andes, Bogotá, Colombia
- Grupo de Diseño de Productos y Procesos (GDPP), Department of Chemical and Food Engineering, Universidad de Los Andes, Bogotá, Colombia
- Max Planck Tandem Group in Computational Biology, Universidad de Los Andes, Bogotá, Colombia
- Grupo de Biología Computacional y Ecología Microbiana, Department of Biological Sciences, Universidad de Los Andes, Bogotá, Colombia
| | - Jonathan Monk
- Systems Biology Research Group, Department of Bioengineering, University of California, San Diego, San Diego, CA, United States
| | - María Juliana Rodríguez Cubillos
- Laboratory of Mycology and Plant Pathology (LAMFU), Department of Chemical and Food Engineering, Universidad de Los Andes, Bogotá, Colombia
- Grupo de Diseño de Productos y Procesos (GDPP), Department of Chemical and Food Engineering, Universidad de Los Andes, Bogotá, Colombia
| | | | - Mariana Restrepo
- Laboratory of Mycology and Plant Pathology (LAMFU), Department of Chemical and Food Engineering, Universidad de Los Andes, Bogotá, Colombia
| | - Vivian Bernal-Galeano
- Laboratory of Mycology and Plant Pathology (LAMFU), Department of Chemical and Food Engineering, Universidad de Los Andes, Bogotá, Colombia
| | - Alejandro Reyes
- Max Planck Tandem Group in Computational Biology, Universidad de Los Andes, Bogotá, Colombia
- Grupo de Biología Computacional y Ecología Microbiana, Department of Biological Sciences, Universidad de Los Andes, Bogotá, Colombia
| | - Andrés González Barrios
- Grupo de Diseño de Productos y Procesos (GDPP), Department of Chemical and Food Engineering, Universidad de Los Andes, Bogotá, Colombia
| | - Bernhard Ø. Palsson
- Systems Biology Research Group, Department of Bioengineering, University of California, San Diego, San Diego, CA, United States
| | - Silvia Restrepo
- Laboratory of Mycology and Plant Pathology (LAMFU), Department of Chemical and Food Engineering, Universidad de Los Andes, Bogotá, Colombia
| | - Adriana Bernal
- Laboratory of Molecular Interactions of Agricultural Microbes, LIMMA, Department of Biological Sciences, Universidad de Los Andes, Bogotá, Colombia
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16
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The ecnA Antitoxin Is Important Not Only for Human Pathogens: Evidence of Its Role in the Plant Pathogen Xanthomonas citri subsp. citri. J Bacteriol 2019; 201:JB.00796-18. [PMID: 31358614 DOI: 10.1128/jb.00796-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 07/24/2019] [Indexed: 11/20/2022] Open
Abstract
Xanthomonas citri subsp. citri causes citrus canker disease worldwide in most commercial varieties of citrus. Its transmission occurs mainly by wind-driven rain. Once X. citri reaches a leaf, it can epiphytically survive by forming a biofilm, which enhances the persistence of the bacteria under different environmental stresses and plays an important role in the early stages of host infection. Therefore, the study of genes involved in biofilm formation has been an important step toward understanding the bacterial strategy for survival in and infection of host plants. In this work, we show that the ecnAB toxin-antitoxin (TA) system, which was previously identified only in human bacterial pathogens, is conserved in many Xanthomonas spp. We further show that in X. citri, ecnA is involved in important processes, such as biofilm formation, exopolysaccharide (EPS) production, and motility. In addition, we show that ecnA plays a role in X. citri survival and virulence in host plants. Thus, this mechanism represents an important bacterial strategy for survival under stress conditions.IMPORTANCE Very little is known about TA systems in phytopathogenic bacteria. ecnAB, in particular, has only been studied in bacterial human pathogens. Here, we showed that it is present in a wide range of Xanthomonas sp. phytopathogens; moreover, this is the first work to investigate the functional role of this TA system in Xanthomonas citri biology, suggesting an important new role in adaptation and survival with implications for bacterial pathogenicity.
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17
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Andrade M, Wang N. The Tad Pilus Apparatus of ' Candidatus Liberibacter asiaticus' and Its Regulation by VisNR. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:1175-1187. [PMID: 30925227 DOI: 10.1094/mpmi-02-19-0052-r] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Citrus huanglongbing (HLB) is one of the most destructive diseases affecting citrus plants. 'Candidatus Liberibacter asiaticus', an uncultivated α-proteobacteria, is the most widely spread causal agent of HLB and is transmitted by the Asian citrus psyllid Diaphorina citri. 'Ca. L. asiaticus' attachment to the psyllid midgut is believed to be critical to further infect other organs, including the salivary gland. In this study, the type IVc tight adherence (Tad) pilus locus encoded by 'Ca. L. asiaticus' was characterized. The Tad loci are conserved among members of Rhizobiaceae, including 'Ca. L. asiaticus' and Agrobacterium spp. Ectopic expression of the 'Ca. L. asiaticus' cpaF gene, an ATPase essential for the biogenesis and secretion of the Tad pilus, restored the adherence phenotype in cpaF mutant of A. tumefaciens, indicating CpaF of 'Ca. L. asiaticus' was functional and critical for bacterial adherence mediated by Tad pilus. Quantitative reverse transcription PCR (qRT-PCR) analysis revealed that 'Ca. L. asiaticus' Tad pilus-encoding genes and 'Ca. L. asiaticus' pilin gene flp3 were upregulated in psyllids compared with in planta. A bacterial one-hybrid assay showed that 'Ca. L. asiaticus' VisN and VisR, members of the LuxR transcriptional factor family, were bound to the flp3 promoter. VisNR regulate flp3. Negative regulation of the flp3 promoter by both VisN and VisR was demonstrated using a shuttle strategy, with analysis of the phenotypes and immunoblotting together with quantification of the expression of the flp3 promoter fused to the β-galactosidase reporter gene. Comparative expression analysis confirmed that 'Ca. L. asiaticus' visNR was less expressed in the psyllid than in the plant host. Further, motility and biofilm phenotypes of the visNR mutant of A. tumefaciens were fully complemented by expressing 'Ca. L. asiaticus' visNR together. The physical interaction between VisN and VisR was confirmed by pull-down and stability assays. The interaction of the flp3 promoter with VisR was verified by electrophoretic mobility shift assay. Taken together, the results revealed the contribution of the Tad pilus apparatus in the colonization of the insect vector by 'Ca. L. asiaticus' and shed light on the involvement of VisNR in regulation of the Tad locus.
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Affiliation(s)
- Maxuel Andrade
- Citrus Research and Education Center (CREC), Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850, U.S.A
| | - Nian Wang
- Citrus Research and Education Center (CREC), Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850, U.S.A
- China-USA Citrus Huanglongbing Joint Laboratory (A joint laboratory of the University of Florida Institute of Food and Agricultural Sciences and Gannan Normal University), National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou 341000, China
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18
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Pruvost O, Boyer K, Ravigné V, Richard D, Vernière C. Deciphering how plant pathogenic bacteria disperse and meet: Molecular epidemiology of Xanthomonas citri pv. citri at microgeographic scales in a tropical area of Asiatic citrus canker endemicity. Evol Appl 2019; 12:1523-1538. [PMID: 31462912 PMCID: PMC6708428 DOI: 10.1111/eva.12788] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/25/2019] [Accepted: 02/24/2019] [Indexed: 12/15/2022] Open
Abstract
Although some plant pathogenic bacteria represent a significant threat to agriculture, the determinants of their ecological success and evolutionary potential are still poorly understood. Refining our understanding of bacterial strain circulation at small spatial scales and the biological significance and evolutionary consequences of co-infections are key questions. The study of bacterial population biology can be challenging, because it requires high-resolution markers that can be genotyped with a high throughput. Here, we overcame this difficulty for Xanthomonas citri pv. citri, a genetically monomorphic bacterium causing Asiatic citrus canker (ACC). Using a genotyping method that did not require cultivating the bacterium or purifying DNA, we deciphered the pathogen's spatial genetic structure at several microgeographic scales, down to single lesion, in a situation of ACC endemicity. In a grove where copper was recurrently applied for ACC management, copper-susceptible and copper-resistant X. citri pv. citri coexisted and the bacterial population structured as three genetic clusters, suggesting a polyclonal contamination. The range of spatial dependency, estimated for the two largest clusters, was four times greater for the cluster predominantly composed of copper-resistant bacteria. Consistently, the evenness value calculated for this cluster was indicative of increased transmission. Linkage disequilibrium was high even at a tree scale, probably due to a combination of clonality and admixture. Approximately 1% of samples exhibited within-lesion multilocus polymorphism, explained at least in part by polyclonal infections. Canker lesions, which are of major biological significance as an inoculum source, may also represent a preferred niche for horizontal gene transfer. This study points out the potential of genotyping data for estimating the range of spatial dependency of plant bacterial pathogens, an important parameter for guiding disease management strategies.
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Affiliation(s)
| | | | | | - Damien Richard
- CIRADUMR PVBMTSaint Pierre, La RéunionFrance
- ANSESSaint Pierre, La RéunionFrance
- Université de la RéunionUMR PVBMTSaint Denis, La RéunionFrance
| | - Christian Vernière
- CIRADUMR PVBMTSaint Pierre, La RéunionFrance
- CIRADUMR BGPIMontpellierFrance
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19
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Garita-Cambronero J, Sena-Vélez M, Ferragud E, Sabuquillo P, Redondo C, Cubero J. Xanthomonas citri subsp. citri and Xanthomonas arboricola pv. pruni: Comparative analysis of two pathogens producing similar symptoms in different host plants. PLoS One 2019; 14:e0219797. [PMID: 31318915 PMCID: PMC6639005 DOI: 10.1371/journal.pone.0219797] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 07/01/2019] [Indexed: 01/06/2023] Open
Abstract
Comparative studies in Xanthomonas have provided a vast amount of data that enabled to deepen in the knowledge of those factors associated with virulence and Xanthomonas plant interaction. The species of this genus present a wide range of host plants and a large number of studies have been focused to elucidate which mechanism are involved in this characteristic. In this study, comparative genomic and phenotypic analysis were performed between X. citri subsp. citri (Xcc), one of the most studied pathogens within Xanthomonas, and X. arboricola pv. pruni (Xap), a pathogen which has aroused great interest in recent time. The work was aimed to find those elements that contribute to their host divergence despite the convergence in the symptoms that each species cause on Citrus spp. and Prunus spp., respectively. This study reveals a set of genes that could be putatively associated with the adaptation of these pathogens to their hosts, being the most remarkable those involved in environmental sensing systems such as the case of the TonB-dependent transporters, the sensors of the two-component system and the methyl accepting chemotaxis proteins. Other important variants were found in processes related to the decomposition of the cell wall as could be appreciated by their dissimilar set of cell-wall degrading enzymes. Type three effectors, as one of the most important factors in delineating the host specificity in Xanthomonas, also showed a different array when comparing both species, being some of them unique to each pathogen. On the other hand, only small variations could be connected to other features such as the motility appendages and surface adhesion proteins, but these differences were accompanied by a dissimilar capacity to attach on host and non-host leaf surface. The molecular factors found in this work provide the basis to perform a more in-depth functional analyses that unveil those actual factors associated with pathogenesis and host specificity in Xcc and Xap.
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Affiliation(s)
- Jerson Garita-Cambronero
- Departamento de Protección Vegetal, Laboratorio Bacteriología, Instituto Nacional de Investigación y Tecnología Agraria (INIA), Madrid, Spain.,Centro de Investigación de Biocombustibles y Bioproductos, Instituto Tecnológico Agrario de Castilla y León (ITACyL), Villarejo de Órbigo, Leon, Spain
| | - Marta Sena-Vélez
- Departamento de Protección Vegetal, Laboratorio Bacteriología, Instituto Nacional de Investigación y Tecnología Agraria (INIA), Madrid, Spain.,Department of Biological Science, Florida State University, Tallahassee, Florida, United States of America
| | - Elisa Ferragud
- Departamento de Protección Vegetal, Laboratorio Bacteriología, Instituto Nacional de Investigación y Tecnología Agraria (INIA), Madrid, Spain
| | - Pilar Sabuquillo
- Departamento de Protección Vegetal, Laboratorio Bacteriología, Instituto Nacional de Investigación y Tecnología Agraria (INIA), Madrid, Spain
| | - Cristina Redondo
- Departamento de Protección Vegetal, Laboratorio Bacteriología, Instituto Nacional de Investigación y Tecnología Agraria (INIA), Madrid, Spain
| | - Jaime Cubero
- Departamento de Protección Vegetal, Laboratorio Bacteriología, Instituto Nacional de Investigación y Tecnología Agraria (INIA), Madrid, Spain
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20
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Teper D, Zhang Y, Wang N. TfmR, a novel TetR-family transcriptional regulator, modulates the virulence of Xanthomonas citri in response to fatty acids. MOLECULAR PLANT PATHOLOGY 2019; 20:701-715. [PMID: 30919570 PMCID: PMC6637906 DOI: 10.1111/mpp.12786] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The type III secretion system (T3SS) is required for Xanthomonas citri subsp. citri (Xcc) virulence by translocating effectors into host cytoplasm to promote disease development. The T3SS is controlled by the master transcriptional regulators HrpG and HrpX. While the function of HrpG and HrpX are well characterized, their upstream regulation remains elusive. By using transposon mutagenesis, we identified XAC3052, a TetR-family transcriptional regulator, which regulates T3SS gene expression. Deletion of XAC3052 caused significant reduction in the expression of T3SS and effector genes in vitro and in planta; as well as reduction of virulence in sweet orange (Citrus sinensis). Overexpression of hrpG restored the virulence of ∆XAC3052, suggesting that the loss of virulence is caused by reduction of T3SS gene expression. XAC3052 directly binds to the promoter region and represses the transcription of fadE, mhpC and fadH genes. FadE, MhpC and FadH are not involved in T3SS regulation, but involved in fatty acid catabolism. ∆XAC3052 displays altered fatty acid composition and retarded growth in environments limited in fatty acids. Exogenously supplemented long-chain fatty acids activate the fadE/mhpC promoter and suppress T3SS promoters in wild-type Xac but not in ∆XAC3052. Moreover, the binding of XAC3052 to its target promoter was disrupted by long-chain fatty acids in vitro. Herein, XAC3052 is designated as TfmR (T3SS and Fatty acid Mechanism Regulator). This study identifies a novel regulator of fatty acid metabolism and suggests that fatty acids play an important role in the metabolic control of virulence in Xcc.
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Affiliation(s)
- Doron Teper
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural SciencesUniversity of Florida700 Experiment Station RoadLake Alfred33850USA
| | - Yanan Zhang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural SciencesUniversity of Florida700 Experiment Station RoadLake Alfred33850USA
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural SciencesUniversity of Florida700 Experiment Station RoadLake Alfred33850USA
- China-USA Citrus Huanglongbing Joint Laboratory (A joint laboratory of The University of Florida’s Institute of Food and Agricultural Sciences and Gannan Normal University), National Navel Orange Engineering Research CenterGannan Normal UniversityGanzhou341000JiangxiChina
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21
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Conforte VP, Malamud F, Yaryura PM, Toum Terrones L, Torres PS, De Pino V, Chazarreta CN, Gudesblat GE, Castagnaro AP, R. Marano M, Vojnov AA. The histone-like protein HupB influences biofilm formation and virulence in Xanthomonas citri ssp. citri through the regulation of flagellar biosynthesis. MOLECULAR PLANT PATHOLOGY 2019; 20:589-598. [PMID: 30537413 PMCID: PMC6637892 DOI: 10.1111/mpp.12777] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Citrus canker is an important disease of citrus, whose causal agent is the bacterium Xanthomonas citri ssp. citri (Xcc). In previous studies, we found a group of Xcc mutants, generated by the insertion of the Tn5 transposon, which showed impaired ability to attach to an abiotic substrate. One of these mutants carries the Tn5 insertion in hupB, a gene encoding a bacterial histone-like protein, homologue to the β-subunit of the Heat-Unstable (HU) nucleoid protein of Escherichia coli. These types of protein are necessary to maintain the bacterial nucleoid organization and the global regulation of gene expression. Here, we characterized the influence of the mutation in hupB regarding Xcc biofilm formation and virulence. The mutant strain hupB was incapable of swimming in soft agar, whereas its complemented strain partially recovered this phenotype. Electron microscope imaging revealed that impaired motility of hupB was a consequence of the absence of the flagellum. Comparison of the expression of flagellar genes between the wild-type strain and hupB showed that the mutant exhibited decreased expression of fliC (encoding flagellin). The hupB mutant also displayed reduced virulence compared with the wild-type strain when they were used to infect Citrus lemon plants using different infection methods. Our results therefore show that the histone-like protein HupB plays an essential role in the pathogenesis of Xcc through the regulation of biofilm formation and biosynthesis of the flagellum.
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Affiliation(s)
- Valeria P. Conforte
- Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, CONICETSaladillo 2468Ciudad de Buenos AiresC1440FFXArgentina
| | - Florencia Malamud
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San MartínCampus Migueletes, 25 de Mayo y FranciaGeneral San MartínB1650HMN Provincia de Buenos AiresArgentina
| | - Pablo M. Yaryura
- Centro de Investigaciones y Transferencia de Villa María CONICETUniversidad de Villa MaríaCarlos Pellegrini 211Villa María, X5900FSECórdobaArgentina
| | - Laila Toum Terrones
- Departamento de FisiologíaBiología Molecular y Celular, Instituto de Biodiversidad y Biología Experimental y Aplicada, CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresIntendente Güiraldes 2160Buenos AiresC1428EGAArgentina
| | - Pablo S. Torres
- Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, CONICETSaladillo 2468Ciudad de Buenos AiresC1440FFXArgentina
| | - Verónica De Pino
- Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, CONICETSaladillo 2468Ciudad de Buenos AiresC1440FFXArgentina
| | - Cristian N. Chazarreta
- Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, CONICETSaladillo 2468Ciudad de Buenos AiresC1440FFXArgentina
| | - Gustavo E. Gudesblat
- Instituto de Tecnología Agroindustrial del Noroeste Argentino (ITANOA), Estación Experimental Agroindustrial Obispo Colombres (EEAOC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)Av. William Cross 3150Las TalitasC.P. T4101XACTucumánArgentina
| | - Atilio P. Castagnaro
- Departamento de FisiologíaBiología Molecular y Celular, Instituto de Biodiversidad y Biología Experimental y Aplicada, CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresIntendente Güiraldes 2160Buenos AiresC1428EGAArgentina
| | - María R. Marano
- Instituto de Biología Molecular y Celular de Rosario, Departamento de Microbiología, Facultad de Ciencias, Bioquímicas y FarmacéuticasUniversidad Nacional de RosarioSuipacha 531RosarioS2002LRKSanta FéArgentina
| | - Adrian A. Vojnov
- Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, CONICETSaladillo 2468Ciudad de Buenos AiresC1440FFXArgentina
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22
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Wu W, Zhao Z, Luo X, Fan X, Zhuo T, Hu X, Liu J, Zou H. Response regulator VemR regulates the transcription of flagellar rod gene flgG by interacting with σ 54 factor RpoN2 in Xanthomonas citri ssp. citri. MOLECULAR PLANT PATHOLOGY 2019; 20:372-381. [PMID: 30353625 PMCID: PMC6637908 DOI: 10.1111/mpp.12762] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Xanthomonas citri ssp. citri, a polar flagellated bacterium, causes citrus canker disease worldwide. In this study, we found that the X. citri ssp. citri response regulator VemR plays a regulatory role in flagellum-derived cell motility. Deletion of the vemR gene resulted in a reduction in cell motility, as well as reductions in virulence and exopolysaccharide production. Reverse transcription-polymerase chain reaction (RT-PCR) demonstrated that vemR is transcribed in an operon together with rpoN2 and fleQ. In the vemR mutant, the flagellar distal rod gene flgG was significantly down-regulated. Because flgG is also rpoN2 dependent, we speculated that VemR and RpoN2 physically interact, which was confirmed by yeast two-hybrid and maltose-binding protein (MBP) pull-down assays. This suggested that the transcription of flgG is synergistically controlled by VemR and RpoN2. To confirm this, we constructed a vemR and rpoN2 double mutant. In this mutant, the reductions in cell motility and flgG transcription were unable to be restored by the expression of either vemR or rpoN2 alone. In contrast, the expression of both vemR and rpoN2 together in the double mutant restored the wild-type phenotype. Together, our data demonstrate that the response regulator VemR functions as an RpoN2 cognate activator to positively regulate the transcription of the rod gene flgG in X. citri ssp. citri.
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Affiliation(s)
- Wei Wu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian University Key Laboratory for Plant–Microbe Interaction, College of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhou350002China
| | - Zhiwen Zhao
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian University Key Laboratory for Plant–Microbe Interaction, College of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhou350002China
| | - Xuming Luo
- State Key Laboratory of Plant Genomics, Institute of MicrobiologyChinese Academy of SciencesBeijing100101China
| | - Xiaojing Fan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian University Key Laboratory for Plant–Microbe Interaction, College of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhou350002China
| | - Tao Zhuo
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian University Key Laboratory for Plant–Microbe Interaction, College of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhou350002China
| | - Xun Hu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian University Key Laboratory for Plant–Microbe Interaction, College of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhou350002China
| | - Jun Liu
- State Key Laboratory of Plant Genomics, Institute of MicrobiologyChinese Academy of SciencesBeijing100101China
| | - Huasong Zou
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian University Key Laboratory for Plant–Microbe Interaction, College of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhou350002China
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23
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Phosphodiesterase EdpX1 Promotes Xanthomonas oryzae pv. oryzae Virulence, Exopolysaccharide Production, and Biofilm Formation. Appl Environ Microbiol 2018; 84:AEM.01717-18. [PMID: 30217836 DOI: 10.1128/aem.01717-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 09/06/2018] [Indexed: 12/22/2022] Open
Abstract
In Xanthomonas oryzae pv. oryzae, the bacterial blight pathogen of rice, there are over 20 genes encoding GGDEF, EAL, and HD-GYP domains, which are potentially involved in the metabolism of second messenger c-di-GMP. In this study, we focused on the characterization of an EAL domain protein, EdpX1. Deletion of the edpX1 gene resulted in a 2-fold increase in the intracellular c-di-GMP levels, which were restored to the wild-type levels in the complemented ΔedpX1(pB-edpX1) strain, demonstrating that EdpX1 is an active phosphodiesterase (PDE) in X. oryzae pv. oryzae. In addition, colorimetric assays further confirmed the PDE activity of EdpX1 by showing that the E153A mutation at the EAL motif strongly reduced its activity. Virulence assays on the leaves of susceptible rice showed that the ΔedpX1 mutant was severely impaired in causing disease symptoms. In trans expression of wild-type edpX1, but not edpX1 E153A, was able to complement the weakened virulence phenotype. These results indicated that an active EAL domain is required for EdpX1 to regulate the virulence of X. oryzae pv. oryzae. We then demonstrated that the ΔedpX1 mutant was defective in secreting exopolysaccharide (EPS) and forming biofilms. The expression of edpX1 in the ΔedpX1 mutant, but not edpX1 E153A, restored the defective phenotypes to near-wild-type levels. In addition, we observed that EdpX1-green fluorescent protein (EdpX1-GFP) exhibited multiple subcellular localization foci, and this pattern was dependent on its transmembrane (TM) region, which did not seem to directly contribute to the regulatory function of EdpX1. Thus, we concluded that EdpX1 exhibits PDE activity to control c-di-GMP levels, and its EAL domain is necessary and sufficient for its regulation of virulence in X. oryzae pv. oryzae.IMPORTANCE Bacteria utilize c-di-GMP as a second messenger to regulate various biological functions. The synthesis and degradation of c-di-GMP are catalyzed by GGDEF domains and an EAL or HD-GYP domain, respectively. Multiple genes encoding these domains are often found in one bacterial strain. For example, in the genome of X. oryzae pv. oryzae PXO99A, 26 genes encoding proteins containing these domains were identified. Therefore, to fully appreciate the complexity and specificity of c-di-GMP signaling in X. oryzae pv. oryzae, the enzymatic activities and regulatory functions of each GGDEF, EAL, and HD-GYP domain protein need to be elucidated. In this study, we showed that the EAL domain protein EdpX1 is a major PDE to regulate diverse virulence phenotypes through the c-di-GMP signaling pathway.
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Sorroche F, Bogino P, Russo DM, Zorreguieta A, Nievas F, Morales GM, Hirsch AM, Giordano W. Cell Autoaggregation, Biofilm Formation, and Plant Attachment in a Sinorhizobium meliloti lpsB Mutant. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:1075-1082. [PMID: 30136892 DOI: 10.1094/mpmi-01-18-0004-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Bacterial surface molecules are crucial for the establishment of a successful rhizobia-legume symbiosis, and, in most bacteria, are also critical for adherence properties, surface colonization, and as a barrier for defense. Rhizobial mutants defective in the production of exopolysaccharides (EPSs), lipopolysaccharides (LPSs), or capsular polysaccharides are usually affected in symbiosis with their plant hosts. In the present study, we evaluated the role of the combined effects of LPS and EPS II in cell-to-cell and cell-to-surface interactions in Sinorhizobium meliloti by studying planktonic cell autoaggregation, biofilm formation, and symbiosis with the host plant Medicago sativa. The lpsB mutant, which has a defective core portion of LPS, exhibited a reduction in biofilm formation on abiotic surfaces as well as altered biofilm architecture compared with the wild-type Rm8530 strain. Atomic force microscopy and confocal laser microscopy revealed an increase in polar cell-to-cell interactions in the lpsB mutant, which might account for the biofilm deficiency. However, a certain level of biofilm development was observed in the lpsB strain compared with the EPS II-defective mutant strains. Autoaggregation experiments carried out with LPS and EPS mutant strains showed that both polysaccharides have an impact on the cell-to-cell adhesive interactions of planktonic bacteria. Although the lpsB mutation and the loss of EPS II production strongly stimulated early attachment to alfalfa roots, the number of nodules induced in M. sativa was not increased. Taken together, this work demonstrates that S. meliloti interactions with biotic and abiotic surfaces depend on the interplay between LPS and EPS II.
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Affiliation(s)
- Fernando Sorroche
- 1 Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - Pablo Bogino
- 1 Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - Daniela M Russo
- 2 Fundación Instituto Leloir and IIBBA CONICET, Buenos Aires, Argentina
| | | | - Fiorela Nievas
- 1 Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - Gustavo M Morales
- 3 Departamento de Química, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina; and
| | - Ann M Hirsch
- 4 Department of Molecular, Cell and Developmental Biology and Molecular Biology Institute, University of California-Los Angeles, U.S.A
| | - Walter Giordano
- 1 Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
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25
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Du H, Fan Z, Yang L, Bao X. Synthesis of novel quinazolin-4(3H)-one derivatives containing the 7-oxo-1,2,4-triazolo[1,5-a]pyrimidine moiety as effective agricultural bactericides against the pathogen Xanthomonas oryzae pv. oryzae. Mol Divers 2017; 22:1-10. [PMID: 28879615 DOI: 10.1007/s11030-017-9782-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 08/20/2017] [Indexed: 12/20/2022]
Abstract
A series of novel quinazolin-4-one derivatives (7a-7n) bearing the 7-oxo-1,2,4-triazolo[1,5-a]pyrimidine moiety were designed, synthesized and evaluated for their inhibition activities against phytopathogenic bacteria and fungi in vitro. All of the target compounds were fully characterized through [Formula: see text] NMR, [Formula: see text] NMR, HRMS and IR spectra. Among these compounds, the structure of compound 7e was unambiguously confirmed via single-crystal X-ray diffraction analysis. The turbidimetric assays indicated that compounds 7b, 7d, 7g, 7k and 7n exhibited much more potent inhibition activities against the pathogen Xanthomonas oryzae pv. oryzae (Xoo), relative to control Bismerthiazol. Moreover, antibacterial activities of compounds 7j, 7k and 7n against the pathogen Xanthomonas axonopodis pv. citri (Xac) were comparable to that of control Bismerthiazol. As for the pathogen Ralstonia solanacearum (Rs), only compounds 7g and 7i demonstrated inhibition activities similar to control Thiadiazole-copper. Moreover, this class of compounds did not display inhibition activity against three fungi tested. The above findings indicated that quinazolin-4-one derivatives containing the 7-oxo-1,2,4-triazolo[1,5-a]pyrimidine moiety have a potential as promising candidates for the development of new and more efficient agricultural bactericides.
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Affiliation(s)
- Huan Du
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for Research and Development of Fine Chemicals, Guizhou University, Guiyang, 550025, China
| | - Zhijiang Fan
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for Research and Development of Fine Chemicals, Guizhou University, Guiyang, 550025, China
| | - Lan Yang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for Research and Development of Fine Chemicals, Guizhou University, Guiyang, 550025, China
| | - Xiaoping Bao
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for Research and Development of Fine Chemicals, Guizhou University, Guiyang, 550025, China.
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26
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Moreira LM, Soares MR, Facincani AP, Ferreira CB, Ferreira RM, Ferro MIT, Gozzo FC, Felestrino ÉB, Assis RAB, Garcia CCM, Setubal JC, Ferro JA, de Oliveira JCF. Proteomics-based identification of differentially abundant proteins reveals adaptation mechanisms of Xanthomonas citri subsp. citri during Citrus sinensis infection. BMC Microbiol 2017; 17:155. [PMID: 28693412 PMCID: PMC5504864 DOI: 10.1186/s12866-017-1063-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 07/01/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Xanthomonas citri subsp. citri (Xac) is the causal agent of citrus canker. A proteomic analysis under in planta infectious and non-infectious conditions was conducted in order to increase our knowledge about the adaptive process of Xac during infection. RESULTS For that, a 2D-based proteomic analysis of Xac at 1, 3 and 5 days after inoculation, in comparison to Xac growth in NB media was carried out and followed by MALDI-TOF-TOF identification of 124 unique differentially abundant proteins. Among them, 79 correspond to up-regulated proteins in at least one of the three stages of infection. Our results indicate an important role of proteins related to biofilm synthesis, lipopolysaccharides biosynthesis, and iron uptake and metabolism as possible modulators of plant innate immunity, and revealed an intricate network of proteins involved in reactive oxygen species adaptation during Plants` Oxidative Burst response. We also identified proteins previously unknown to be involved in Xac-Citrus interaction, including the hypothetical protein XAC3981. A mutant strain for this gene has proved to be non-pathogenic in respect to classical symptoms of citrus canker induced in compatible plants. CONCLUSIONS This is the first time that a protein repertoire is shown to be active and working in an integrated manner during the infection process in a compatible host, pointing to an elaborate mechanism for adaptation of Xac once inside the plant.
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Affiliation(s)
- Leandro M Moreira
- Departamento de Ciências Biológicas (DECBI), Instituto de Ciências Exatas e Biológicas (ICEB), Universidade Federal de Ouro Preto (UFOP), Ouro Preto, MG, Brazil. .,Núcleo de Pesquisas em Ciências Biológicas (NUPEB), Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil.
| | - Márcia R Soares
- Departamento de Bioquímica (DBq), Instituto de Química (IQ), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Agda P Facincani
- Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESP - Universidade Estadual Paulista, Departamento de Tecnologia, Jaboticabal, SP, Brazil.
| | - Cristiano B Ferreira
- Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESP - Universidade Estadual Paulista, Departamento de Tecnologia, Jaboticabal, SP, Brazil
| | - Rafael M Ferreira
- Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESP - Universidade Estadual Paulista, Departamento de Tecnologia, Jaboticabal, SP, Brazil
| | - Maria I T Ferro
- Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESP - Universidade Estadual Paulista, Departamento de Tecnologia, Jaboticabal, SP, Brazil
| | - Fábio C Gozzo
- Instituto de Química, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Érica B Felestrino
- Núcleo de Pesquisas em Ciências Biológicas (NUPEB), Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
| | - Renata A B Assis
- Núcleo de Pesquisas em Ciências Biológicas (NUPEB), Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
| | - Camila Carrião M Garcia
- Departamento de Ciências Biológicas (DECBI), Instituto de Ciências Exatas e Biológicas (ICEB), Universidade Federal de Ouro Preto (UFOP), Ouro Preto, MG, Brazil.,Núcleo de Pesquisas em Ciências Biológicas (NUPEB), Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
| | - João C Setubal
- Departamento de Bioquímica (DB), Instituto de Química (IQ), Universidade de São Paulo (USP), São Paulo, SP, Brazil.,Biocomplexity Institute, Virginia Tech, Blacksburg, VA, USA
| | - Jesus A Ferro
- Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESP - Universidade Estadual Paulista, Departamento de Tecnologia, Jaboticabal, SP, Brazil
| | - Julio C F de Oliveira
- Departamento de Ciências Biológicas (DCB), Universidade Federal de São Paulo (UNIFESP), Diadema, SP, Brazil
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27
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Pereira CT, Roesler C, Faria JN, Fessel MR, Balan A. Sulfate-Binding Protein (Sbp) from Xanthomonas citri: Structure and Functional Insights. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:578-588. [PMID: 28562158 DOI: 10.1094/mpmi-02-17-0032-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The uptake and transport of sulfate in bacteria is mediated by an ATP-binding cassette transporter (ABC transporter) encoded by sbpcysUWA genes, whose importance has been widely demonstrated due to their relevance in cysteine synthesis and bacterial growth. In Xanthomonas citri, the causative agent of canker disease, the expression of components from this ABC transporter and others related to uptake of organic sulfur sources has been shown during in vitro growth cultures. In this work, based on gene reporter and proteomics analyses, we showed the activation of the promoter that controls the sbpcysUWA operon in vitro and in vivo and the expression of sulfate-binding protein (Sbp), a periplasmic-binding protein, indicating that this protein plays an important function during growth and that the transport system is active during Citrus sinensis infection. To characterize Sbp, we solved its three-dimensional structure bound to sulfate at 1.14 Å resolution and performed biochemical and functional characterization. The results revealed that Sbp interacts with sulfate without structural changes, but the interaction induces a significant increasing of protein thermal stability. Altogether, the results presented in this study show the evidence of the functionality of the ABC transporter for sulfate in X. citri and its relevance during infection.
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Affiliation(s)
- Cristiane Tambascia Pereira
- 1 Laboratório Nacional de Biociências (LNBio), Centro de Pesquisas em Energia e Materiais (CNPEM), Campinas, São Paulo, Brazil
- 2 Universidade de Campinas-UNICAMP, Instituto de Biologia, Campinas São Paulo, Brazil; and
- 3 Departamento de Microbiologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Cássia Roesler
- 1 Laboratório Nacional de Biociências (LNBio), Centro de Pesquisas em Energia e Materiais (CNPEM), Campinas, São Paulo, Brazil
- 2 Universidade de Campinas-UNICAMP, Instituto de Biologia, Campinas São Paulo, Brazil; and
| | - Jéssica Nascimento Faria
- 1 Laboratório Nacional de Biociências (LNBio), Centro de Pesquisas em Energia e Materiais (CNPEM), Campinas, São Paulo, Brazil
- 2 Universidade de Campinas-UNICAMP, Instituto de Biologia, Campinas São Paulo, Brazil; and
| | - Melissa Regina Fessel
- 1 Laboratório Nacional de Biociências (LNBio), Centro de Pesquisas em Energia e Materiais (CNPEM), Campinas, São Paulo, Brazil
| | - Andrea Balan
- 3 Departamento de Microbiologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, São Paulo, SP, Brazil
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Ficarra FA, Grandellis C, Galván EM, Ielpi L, Feil R, Lunn JE, Gottig N, Ottado J. Xanthomonas citri ssp. citri requires the outer membrane porin OprB for maximal virulence and biofilm formation. MOLECULAR PLANT PATHOLOGY 2017; 18:720-733. [PMID: 27226289 PMCID: PMC6638224 DOI: 10.1111/mpp.12433] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 05/04/2016] [Accepted: 05/23/2016] [Indexed: 05/31/2023]
Abstract
Xanthomonas citri ssp. citri (Xcc) causes canker disease in citrus, and biofilm formation is critical for the disease cycle. OprB (Outer membrane protein B) has been shown previously to be more abundant in Xcc biofilms compared with the planktonic state. In this work, we showed that the loss of OprB in an oprB mutant abolishes bacterial biofilm formation and adherence to the host, and also compromises virulence and efficient epiphytic survival of the bacteria. Moreover, the oprB mutant is impaired in bacterial stress resistance. OprB belongs to a family of carbohydrate transport proteins, and the uptake of glucose is decreased in the mutant strain, indicating that OprB transports glucose. Loss of OprB leads to increased production of xanthan exopolysaccharide, and the carbohydrate intermediates of xanthan biosynthesis are also elevated in the mutant. The xanthan produced by the mutant has a higher viscosity and, unlike wild-type xanthan, completely lacks pyruvylation. Overall, these results suggest that Xcc reprogrammes its carbon metabolism when it senses a shortage of glucose input. The participation of OprB in the process of biofilm formation and virulence, as well as in metabolic changes to redirect the carbon flux, is discussed. Our results demonstrate the importance of environmental nutrient supply and glucose uptake via OprB for Xcc virulence.
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Affiliation(s)
- Florencia A. Ficarra
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (IBR‐CONICET) and Facultad de Ciencias Bioquímicas y FarmacéuticasUniversidad Nacional de Rosario, Ocampo y EsmeraldaRosario2000Argentina
| | - Carolina Grandellis
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (IBR‐CONICET) and Facultad de Ciencias Bioquímicas y FarmacéuticasUniversidad Nacional de Rosario, Ocampo y EsmeraldaRosario2000Argentina
| | - Estela M. Galván
- Laboratory of Bacterial GeneticsFundación Instituto Leloir, IIBBA‐CONICET (C1405BWE)Ciudad de Buenos AiresBuenos AiresArgentina
| | - Luis Ielpi
- Laboratory of Bacterial GeneticsFundación Instituto Leloir, IIBBA‐CONICET (C1405BWE)Ciudad de Buenos AiresBuenos AiresArgentina
| | - Regina Feil
- Max Planck Institute of Molecular Plant PhysiologyWissenschaftspark Potsdam‐GolmAm Mühlenberg 114476 Potsdam‐GolmGermany
| | - John E. Lunn
- Max Planck Institute of Molecular Plant PhysiologyWissenschaftspark Potsdam‐GolmAm Mühlenberg 114476 Potsdam‐GolmGermany
| | - Natalia Gottig
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (IBR‐CONICET) and Facultad de Ciencias Bioquímicas y FarmacéuticasUniversidad Nacional de Rosario, Ocampo y EsmeraldaRosario2000Argentina
| | - Jorgelina Ottado
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (IBR‐CONICET) and Facultad de Ciencias Bioquímicas y FarmacéuticasUniversidad Nacional de Rosario, Ocampo y EsmeraldaRosario2000Argentina
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Velmourougane K, Prasanna R, Saxena AK. Agriculturally important microbial biofilms: Present status and future prospects. J Basic Microbiol 2017; 57:548-573. [PMID: 28407275 DOI: 10.1002/jobm.201700046] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 03/17/2017] [Accepted: 03/19/2017] [Indexed: 11/07/2022]
Abstract
Microbial biofilms are a fascinating subject, due to their significant roles in the environment, industry, and health. Advances in biochemical and molecular techniques have helped in enhancing our understanding of biofilm structure and development. In the past, research on biofilms primarily focussed on health and industrial sectors; however, lately, biofilms in agriculture are gaining attention due to their immense potential in crop production, protection, and improvement. Biofilms play an important role in colonization of surfaces - soil, roots, or shoots of plants and enable proliferation in the desired niche, besides enhancing soil fertility. Although reports are available on microbial biofilms in general; scanty information is published on biofilm formation by agriculturally important microorganisms (bacteria, fungi, bacterial-fungal) and their interactions in the ecosystem. Better understanding of agriculturally important bacterial-fungal communities and their interactions can have several implications on climate change, soil quality, plant nutrition, plant protection, bioremediation, etc. Understanding the factors and genes involved in biofilm formation will help to develop more effective strategies for sustainable and environment-friendly agriculture. The present review brings together fundamental aspects of biofilms, in relation to their formation, regulatory mechanisms, genes involved, and their application in different fields, with special emphasis on agriculturally important microbial biofilms.
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Affiliation(s)
| | - Radha Prasanna
- Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Anil Kumar Saxena
- ICAR-National Bureau of Agriculturally Important Microorganisms (NBAIM), Mau Nath Bhanjan, Uttar Pradesh, India
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Petrocelli S, Arana MR, Cabrini MN, Casabuono AC, Moyano L, Beltramino M, Moreira LM, Couto AS, Orellano EG. Deletion of pilA, a Minor Pilin-Like Gene, from Xanthomonas citri subsp. citri Influences Bacterial Physiology and Pathogenesis. Curr Microbiol 2016; 73:904-914. [PMID: 27664015 DOI: 10.1007/s00284-016-1138-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 09/13/2016] [Indexed: 10/21/2022]
Abstract
Type IV pili (Tfp) are widely distributed adhesins of bacterial surfaces. In plant pathogenic bacteria, Tfp are involved in host colonization and pathogenesis. Xanthomonas citri subsp. citri (Xcc) is the phytopathogen responsible for citrus canker disease. In this work, three Tfp structural genes, fimA, fimA1, and pilA from Xcc were studied. A pilA mutant strain from Xcc (XccΔpilA) was constructed and differences in physiological features, such as motilities, adhesion, and biofilm formation, were observed. A structural study of the purified Tfp fractions from Xcc wild-type and Xcc∆pilA showed that pilins are glycosylated in both strains and that FimA and FimA1 are the main structural components of the pili. Furthermore, smaller lesion symptoms and reduced bacterial growth were produced by Xcc∆pilA in orange plants compared to the wild-type strain. These results indicate that the minor pilin-like gene, pilA, is involved in Tfp performance during the infection process.
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Affiliation(s)
- Silvana Petrocelli
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina
| | - Maite R Arana
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina
| | - Marcela N Cabrini
- Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Centro de Investigaciones en Hidratos de Carbono, Universidad de Buenos Aires, 1428, Buenos Aires, Argentina
| | - Adriana C Casabuono
- Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Centro de Investigaciones en Hidratos de Carbono, Universidad de Buenos Aires, 1428, Buenos Aires, Argentina
| | - Laura Moyano
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina
| | - Matías Beltramino
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina
| | - Leandro M Moreira
- Departamento de Ciências Biológicas (DECBI), Instituto de Ciências Exatas e Biológicas, Campus Morro do Cruzeiro, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
- Núcleo de Pesquisas em Ciências Biológicas (NUPEB), Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
| | - Alicia S Couto
- Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Centro de Investigaciones en Hidratos de Carbono, Universidad de Buenos Aires, 1428, Buenos Aires, Argentina
| | - Elena G Orellano
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina.
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Martins PMM, Machado MA, Silva NV, Takita MA, de Souza AA. Type II Toxin-Antitoxin Distribution and Adaptive Aspects on Xanthomonas Genomes: Focus on Xanthomonas citri. Front Microbiol 2016; 7:652. [PMID: 27242687 PMCID: PMC4861877 DOI: 10.3389/fmicb.2016.00652] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 04/18/2016] [Indexed: 01/09/2023] Open
Abstract
Prokaryotic toxin-antitoxin (TA) systems were first described as being designed to prevent plasmid loss in bacteria. However, with the increase in prokaryotic genome sequencing, recently many TAs have been found in bacterial chromosomes, having other biological functions, such as environmental stress response. To date, only few studies have focused on TA systems in phytopathogens, and their possible impact on the bacterial fitness. This may be especially important for pathogens like Xanthomonas spp., which live epiphytically before entering the host. In this study, we looked for TA systems in the genomes of 10 Xanthomonas strains. We verified that citrus-infecting pathovars have, on average, 50% more TAs than other Xanthomonas spp. and no genome harbors classical toxins such as MqsR, RelB, and HicA. Only one TA system (PIN_VapC-FitB-like/SpoVT_AbrB) was conserved among the Xanthomonas genomes, suggesting adaptive aspects concerning its broad occurrence. We also detected a trend of toxin gene loss in this genus, while the antitoxin gene was preferably maintained. This study discovers the quantitative and qualitative differences among the type II TA systems present in Xanthomonas spp., especially concerning the citrus-infecting strains. In addition, the antitoxin retention in the genomes is possibly related with the resistance mechanism of further TA infections as an anti-addiction system or might also be involved in regulation of certain specific genes.
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Affiliation(s)
- Paula M M Martins
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico Cordeirópolis, Brazil
| | - Marcos A Machado
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico Cordeirópolis, Brazil
| | - Nicholas V Silva
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico Cordeirópolis, Brazil
| | - Marco A Takita
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico Cordeirópolis, Brazil
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Granato LM, Picchi SC, Andrade MDO, Takita MA, de Souza AA, Wang N, Machado MA. The ATP-dependent RNA helicase HrpB plays an important role in motility and biofilm formation in Xanthomonas citri subsp. citri. BMC Microbiol 2016; 16:55. [PMID: 27005008 PMCID: PMC4804567 DOI: 10.1186/s12866-016-0655-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 03/02/2016] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND RNA helicases are enzymes that catalyze the separation of double-stranded RNA (dsRNA) using the free energy of ATP binding and hydrolysis. DEAD/DEAH families participate in many different aspects of RNA metabolism, including RNA synthesis, RNA folding, RNA-RNA interactions, RNA localization and RNA degradation. Several important bacterial DEAD/DEAH-box RNA helicases have been extensively studied. In this study, we characterize the ATP-dependent RNA helicase encoded by the hrpB (XAC0293) gene using deletion and genetic complementation assays. We provide insights into the function of the hrpB gene in Xanthomonas citri subsp. citri by investigating the roles of hrpB in biofilm formation on abiotic surfaces and host leaves, cell motility, host virulence of the citrus canker bacterium and growth in planta. RESULTS The hrpB gene is highly conserved in the sequenced strains of Xanthomonas. Mutation of the hrpB gene (∆hrpB) resulted in a significant reduction in biofilms on abiotic surfaces and host leaves. ∆hrpB also exhibited increased cell dispersion on solid medium plates. ∆hrpB showed reduced adhesion on biotic and abiotic surfaces and delayed development in disease symptoms when sprayed on susceptible citrus leaves. Quantitative reverse transcription-PCR assays indicated that deletion of hrpB reduced the expression of four type IV pili genes. The transcriptional start site of fimA (XAC3241) was determined using rapid amplification of 5'-cDNA Ends (5'RACE). Based on the results of fimA mRNA structure predictions, the fimA 5' UTR may contain three different loops. HrpB may be involved in alterations to the structure of fimA mRNA that promote the stability of fimA RNA. CONCLUSIONS Our data show that hrpB is involved in adherence of Xanthomonas citri subsp. citri to different surfaces. In addition, to the best of our knowledge, this is the first time that a DEAH RNA helicase has been implicated in the regulation of type IV pili in Xanthomonas.
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Affiliation(s)
- Laís Moreira Granato
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera Km 158, Cordeirópolis, SP, 13490-970, Brazil
- Universidade Estadual de Campinas/UNICAMP, Instituto de Biologia, P.O. Box 6010, Campinas, SP, 13083-970, Brazil
| | - Simone Cristina Picchi
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera Km 158, Cordeirópolis, SP, 13490-970, Brazil
| | - Maxuel de Oliveira Andrade
- Citrus Research and Educational Center, Department of Microbiology and Cell Science, University of Florida, IFAS, 700 Experiment Station Road, Lake Alfred, FL, 33850, USA
| | - Marco Aurélio Takita
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera Km 158, Cordeirópolis, SP, 13490-970, Brazil
| | - Alessandra Alves de Souza
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera Km 158, Cordeirópolis, SP, 13490-970, Brazil
| | - Nian Wang
- Citrus Research and Educational Center, Department of Microbiology and Cell Science, University of Florida, IFAS, 700 Experiment Station Road, Lake Alfred, FL, 33850, USA
| | - Marcos Antonio Machado
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera Km 158, Cordeirópolis, SP, 13490-970, Brazil.
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Tondo ML, Delprato ML, Kraiselburd I, Fernández Zenoff MV, Farías ME, Orellano EG. KatG, the Bifunctional Catalase of Xanthomonas citri subsp. citri, Responds to Hydrogen Peroxide and Contributes to Epiphytic Survival on Citrus Leaves. PLoS One 2016; 11:e0151657. [PMID: 26990197 PMCID: PMC4807922 DOI: 10.1371/journal.pone.0151657] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 03/02/2016] [Indexed: 12/19/2022] Open
Abstract
Xanthomonas citri subsp. citri (Xcc) is the bacterium responsible for citrus canker. This bacterium is exposed to reactive oxygen species (ROS) at different points during its life cycle, including those normally produced by aerobic respiration or upon exposition to ultraviolet (UV) radiation. Moreover, ROS are key components of the host immune response. Among enzymatic ROS-detoxifying mechanisms, catalases eliminate H2O2, avoiding the potential damage caused by this specie. Xcc genome includes four catalase genes. In this work, we studied the physiological role of KatG, the only bifunctional catalase of Xcc, through the construction and characterization of a modified strain (XcckatG), carrying an insertional mutation in the katG gene. First, we evaluated the involvement of KatG in the bacterial adaptive response to H2O2. XcckatG cultures exhibited lower catalase activity than those of the wild-type strain, and this activity was not induced upon treatment with sub-lethal doses of H2O2. Moreover, the KatG-deficient mutant exhibited decreased tolerance to H2O2 toxicity compared to wild-type cells and accumulated high intracellular levels of peroxides upon exposure to sub-lethal concentrations of H2O2. To further study the role of KatG in Xcc physiology, we evaluated bacterial survival upon exposure to UV-A or UV-B radiation. In both conditions, XcckatG showed a high mortality in comparison to Xcc wild-type. Finally, we studied the development of bacterial biofilms. While structured biofilms were observed for the Xcc wild-type, the development of these structures was impaired for XcckatG. Based on these results, we demonstrated that KatG is responsible for Xcc adaptive response to H2O2 and a key component of the bacterial response to oxidative stress. Moreover, this enzyme plays an important role during Xcc epiphytic survival, being essential for biofilm formation and UV resistance.
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Affiliation(s)
- María Laura Tondo
- Molecular Biology Division, Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Santa Fe, Argentina
| | - María Laura Delprato
- Molecular Biology Division, Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Santa Fe, Argentina
| | - Ivana Kraiselburd
- Molecular Biology Division, Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Santa Fe, Argentina
| | - María Verónica Fernández Zenoff
- Planta Piloto de Procesos Industriales Microbiológicos, Consejo Nacional de Investigaciones Científicas y Técnicas, San Miguel de Tucumán, Tucumán, Argentina
| | - María Eugenia Farías
- Planta Piloto de Procesos Industriales Microbiológicos, Consejo Nacional de Investigaciones Científicas y Técnicas, San Miguel de Tucumán, Tucumán, Argentina
| | - Elena G. Orellano
- Molecular Biology Division, Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Santa Fe, Argentina
- * E-mail:
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Dunger G, Llontop E, Guzzo CR, Farah CS. The Xanthomonas type IV pilus. Curr Opin Microbiol 2016; 30:88-97. [PMID: 26874963 DOI: 10.1016/j.mib.2016.01.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 01/14/2016] [Accepted: 01/17/2016] [Indexed: 02/07/2023]
Abstract
Type IV pili, a special class of bacterial surface filaments, are key behavioral mediators for many important human pathogens. However, we know very little about the role of these structures in the lifestyles of plant-associated bacteria. Over the past few years, several groups studying the extensive genus of Xanthomonas spp. have gained insights into the roles of played by type IV pili in bacteria-host interactions and pathogenesis, motility, biofilm formation, and interactions with bacteriophages. Protein-protein interaction studies have identified T4P regulators and these, along with structural studies, have begun to reveal some of the possible molecular mechanisms that may control the extension/retraction cycles of these dynamic filaments.
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Affiliation(s)
- German Dunger
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP 05508-000, Brazil
| | - Edgar Llontop
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP 05508-000, Brazil
| | - Cristiane R Guzzo
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes 1374, São Paulo, SP CEP 05508-900, Brazil
| | - Chuck S Farah
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP 05508-000, Brazil.
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Mensi I, Daugrois JH, Pieretti I, Gargani D, Fleites LA, Noell J, Bonnot F, Gabriel DW, Rott P. Surface polysaccharides and quorum sensing are involved in the attachment and survival of Xanthomonas albilineans on sugarcane leaves. MOLECULAR PLANT PATHOLOGY 2016; 17:236-246. [PMID: 25962850 PMCID: PMC6638434 DOI: 10.1111/mpp.12276] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Xanthomonas albilineans, the causal agent of sugarcane leaf scald, is a bacterial plant pathogen that is mainly spread by infected cuttings and contaminated harvesting tools. However, some strains of this pathogen are known to be spread by aerial means and are able to colonize the phyllosphere of sugarcane before entering the host plant and causing disease. The objective of this study was to identify the molecular factors involved in the survival or growth of X. albilineans on sugarcane leaves. We developed a bioassay to test for the attachment of X. albilineans on sugarcane leaves using tissue-cultured plantlets grown in vitro. Six mutants of strain XaFL07-1 affected in surface polysaccharide production completely lost their capacity to survive on the sugarcane leaf surface. These mutants produced more biofilm in vitro and accumulated more cellular poly-β-hydroxybutyrate than the wild-type strain. A mutant affected in the production of small molecules (including potential biosurfactants) synthesized by non-ribosomal peptide synthetases (NRPSs) attached to the sugarcane leaves as well as the wild-type strain. Surprisingly, the attachment of bacteria on sugarcane leaves varied among mutants of the rpf gene cluster involved in bacterial quorum sensing. Therefore, quorum sensing may affect polysaccharide production, or both polysaccharides and quorum sensing may be involved in the survival or growth of X. albilineans on sugarcane leaves.
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Affiliation(s)
- Imene Mensi
- UMR BGPI, CIRAD, F-34398, Montpellier, France
| | | | | | | | - Laura A Fleites
- Plant Pathology Department, University of Florida, Gainesville, 32611, USA
| | - Julie Noell
- UMR BGPI, CIRAD, F-34398, Montpellier, France
| | | | - Dean W Gabriel
- Plant Pathology Department, University of Florida, Gainesville, 32611, USA
| | - Philippe Rott
- UMR BGPI, CIRAD, F-34398, Montpellier, France
- Plant Pathology Department, University of Florida, Gainesville, 32611, USA
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Gordon JL, Lefeuvre P, Escalon A, Barbe V, Cruveiller S, Gagnevin L, Pruvost O. Comparative genomics of 43 strains of Xanthomonas citri pv. citri reveals the evolutionary events giving rise to pathotypes with different host ranges. BMC Genomics 2015; 16:1098. [PMID: 26699528 PMCID: PMC4690215 DOI: 10.1186/s12864-015-2310-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 12/15/2015] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The identification of factors involved in the host range definition and evolution is a pivotal challenge in the goal to predict and prevent the emergence of plant bacterial disease. To trace the evolution and find molecular differences between three pathotypes of Xanthomonas citri pv. citri that may explain their distinctive host ranges, 42 strains of X. citri pv. citri and one outgroup strain, Xanthomonas citri pv. bilvae were sequenced and compared. RESULTS The strains from each pathotype form monophyletic clades, with a short branch shared by the A(w) and A pathotypes. Pathotype-specific recombination was detected in seven regions of the alignment. Using Ancestral Character Estimation, 426 SNPs were mapped to the four branches at the base of the A, A*, A(w) and A/A(w) clades. Several genes containing pathotype-specific nonsynonymous mutations have functions related to pathogenicity. The A pathotype is enriched for SNP-containing genes involved in defense mechanisms, while A* is significantly depleted for genes that are involved in transcription. The pathotypes differ by four gene islands that largely coincide with regions of recombination and include genes with a role in virulence. Both A* and A(w) are missing genes involved in defense mechanisms. In contrast to a recent study, we find that there are an extremely small number of pathotype-specific gene presences and absences. CONCLUSIONS The three pathotypes of X. citri pv. citri that differ in their host ranges largely show genomic differences related to recombination, horizontal gene transfer and single nucleotide polymorphism. We detail the phylogenetic relationship of the pathotypes and provide a set of candidate genes involved in pathotype-specific evolutionary events that could explain to the differences in host range and pathogenicity between them.
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Affiliation(s)
- Jonathan L Gordon
- Université de la Réunion, UMR PVBMT, 97410, Saint-Pierre, La Réunion, France.
- Current Address: CIRAD, UMR CMAEE, F-97170, Petit-Bourg, Guadeloupe, France.
| | | | - Aline Escalon
- CIRAD, UMR PVBMT, 97410, Saint-Pierre, La Réunion, France.
| | - Valérie Barbe
- CEA/DSV/IG/Genoscope, 2 rue Gaston Crémieux, BP5706, 91057, Evry, France.
| | | | - Lionel Gagnevin
- CIRAD, UMR PVBMT, 97410, Saint-Pierre, La Réunion, France.
- Current Address: UMR IPME, IRD-CIRAD-Université Montpellier, 34394, Montpellier, France.
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Zhang Y, Jalan N, Zhou X, Goss E, Jones JB, Setubal JC, Deng X, Wang N. Positive selection is the main driving force for evolution of citrus canker-causing Xanthomonas. THE ISME JOURNAL 2015; 9:2128-38. [PMID: 25689023 PMCID: PMC4579464 DOI: 10.1038/ismej.2015.15] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 12/29/2014] [Accepted: 01/06/2015] [Indexed: 12/13/2022]
Abstract
Understanding the evolutionary history and potential of bacterial pathogens is critical to prevent the emergence of new infectious bacterial diseases. Xanthomonas axonopodis subsp. citri (Xac) (synonym X. citri subsp. citri), which causes citrus canker, is one of the hardest-fought plant bacterial pathogens in US history. Here, we sequenced 21 Xac strains (14 XacA, 3 XacA* and 4 XacA(w)) with different host ranges from North America and Asia and conducted comparative genomic and evolutionary analyses. Our analyses suggest that acquisition of beneficial genes and loss of detrimental genes most likely allowed XacA to infect a broader range of hosts as compared with XacA(w) and XacA*. Recombination was found to have occurred frequently on the relative ancient branches, but rarely on the young branches of the clonal genealogy. The ratio of recombination/mutation ρ/θ was 0.0790±0.0005, implying that the Xac population was clonal in structure. Positive selection has affected 14% (395 out of 2822) of core genes of the citrus canker-causing Xanthomonas. The genes affected are enriched in 'carbohydrate transport and metabolism' and 'DNA replication, recombination and repair' genes (P<0.05). Many genes related to virulence, especially genes involved in the type III secretion system and effectors, are affected by positive selection, further highlighting the contribution of positive selection to the evolution of citrus canker-causing Xanthomonas. Our results suggest that both metabolism and virulence genes provide advantages to endow XacA with higher virulence and a wider host range. Our analysis advances our understanding of the genomic basis of specialization by positive selection in bacterial evolution.
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Affiliation(s)
- Yunzeng Zhang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL, USA
| | - Neha Jalan
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL, USA
| | - Xiaofeng Zhou
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL, USA
| | - Erica Goss
- Department of Plant Pathology, University of Florida, Gainesville, FL, USA
| | - Jeffrey B Jones
- Department of Plant Pathology, University of Florida, Gainesville, FL, USA
| | - João C Setubal
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Xiaoling Deng
- Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL, USA
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Matsuhashi A, Tahara H, Ito Y, Uchiyama J, Ogawa S, Ohta H. Slr2019, lipid A transporter homolog, is essential for acidic tolerance in Synechocystis sp. PCC6803. PHOTOSYNTHESIS RESEARCH 2015; 125:267-277. [PMID: 25822232 DOI: 10.1007/s11120-015-0129-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 03/23/2015] [Indexed: 06/04/2023]
Abstract
Living organisms must defend themselves against various environmental stresses. Extracellular polysaccharide-producing cells exhibit enhanced tolerance toward adverse environmental stress. In Synechocystis sp. PCC6803 (Synechocystis), lipopolysaccharide (LPS) may play a role in this protection. To examine the relationship between stress tolerance of Synechocystis and LPS, we focused on Slr2019 because Slr2019 is homologous to MsbA in Escherichia coli, which is related to LPS synthesis. First, to obtain a defective mutant of LPS, we constructed the slr2019 insertion mutant (slr2019) strain. Sodium deoxycholate-polyacrylamide gel electrophoresis indicated that slr2019 strain did not synthesize normal LPS. Second, to clarify the participation of LPS in acid tolerance, wild type (WT) and slr2019 strain were grown under acid stress; slr2019 strain growth was significantly weaker than WT growth. Third, to examine influences on stress tolerance, slr2019 strain was grown under various stresses. Under salinity and temperature stress, slr2019 strain grew significantly slower than WT. To confirm cell morphology, cell shape and envelope of slr2019 strain were observed by transmission electron microscopy; slr2019 cells contained more electron-transparent bodies than WT cells. Finally, to confirm whether electron-transparent bodies are poly-3-hydroxybutyrate (PHB), slr2019 strain was stained with Nile Blue A, a PHB detector, and observed by fluorescence microscopy. The PHB granule content ratio of WT and slr2019 strain grown at BG-11 pH 8.0 was each 7.18 and 8.41 %. At pH 6.0, the PHB granule content ratio of WT and slr2019 strain was 2.99 and 2.60 %. However, the PHB granule content ratio of WT and slr2019 strain grown at BG-11N-reduced was 10.82 and 0.56 %. Because slr2019 strain significantly decreased PHB under BG-11N-reduced compared with WT, LPS synthesis may be related to PHB under particular conditions. These results indicated that Slr2019 is necessary for Synechocystis survival in various stresses.
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Affiliation(s)
- Ayumi Matsuhashi
- Graduate School of Mathematics and Science Education, Tokyo University of Science, Shinjuku-ku, Tokyo, 162-8601, Japan,
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Abstract
Bacterial blight of rice is an important serious bacterial diseases of rice in many rice-growing regions, caused by Xanthomonas oryzae pv. oryzae (Xoo). The thiG gene from Xoo strain ZJ173, which is involved with thiazole moiety production in the thiamine biosynthesis pathway, is highly conserved among the members of Xanthomonas. The thiG deletion mutant displayed impaired virulence and growth in thiamine-free medium but maintained its normal growth rate in the rice tissues, indicating that the thiG gene is involved in Xoo virulence. Compared to the wild type strain, the formation of cell-cell aggregates was affected in thiG deletion mutants. Although biofilm formation was promoted, motility and migration in rice leaves were repressed in the thiG mutants, and therefore limited the expansion of pathogen infection in rice. Quorum sensing and extracellular substance are two key factors that contribute to the formation of cell-cell aggregates. Our study found that in the thiG mutant the expression of two genes, rpfC and rpfG, which form a two-component regulatory signal system involved in the regulation of biofilm formation by a second messenger cyclic di-GMP is down-regulated. In addition, our study showed that xanthan production was not affected but the expression of some genes associated with xanthan biosynthesis, like gumD, gumE, gumH and gumM, were up-regulated in thiG mutants. Taken together, these findings are the first to demonstrate the role of the thiazole biosynthsis gene, thiG, in virulence and the formation of aggregates in Xanthomonas oryzae pv. oryzae.
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40
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Li H, Yu C, Chen H, Tian F, He C. PXO_00987, a putative acetyltransferase, is required for flagellin glycosylation, and regulates flagellar motility, exopolysaccharide production, and biofilm formation in Xanthomonas oryzae pv. oryzae. Microb Pathog 2015; 85:50-7. [PMID: 26065383 DOI: 10.1016/j.micpath.2015.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 05/27/2015] [Accepted: 06/05/2015] [Indexed: 10/23/2022]
Abstract
Acetyltransferases catalyze an important process for sugar or protein modification. In the genome of Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial blight of rice, there are 32 acetyltransferase-encoding genes belonging to different families. In this work, we focused on PXO_00987, which encodes a putative acetyltransferase in the flagellar regulon. We found that mutation of PXO_00987 gene abolished the glycosylation of wild-type flagellin protein of Xoo. In addition, the PXO_00987 mutant showed enhanced swimming motility, and decreased exopolysaccharide production and biofilm formation. Virulence assays demonstrated that the PXO_00987 mutant caused shorter disease length on rice leaves, suggesting that the function of PXO_00987 contributes to the pathogenesis of Xoo.
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Affiliation(s)
- Haiyun Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Chao Yu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Huamin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Fang Tian
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Chenyang He
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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Identification of seven novel virulence genes from Xanthomonas citri subsp. citri by Tn5-based random mutagenesis. J Microbiol 2015; 53:330-6. [PMID: 25935304 DOI: 10.1007/s12275-015-4589-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 03/03/2015] [Accepted: 03/28/2015] [Indexed: 10/23/2022]
Abstract
To identify novel virulence genes, a mutant library of Xanthomonas citri subsp. citri 29-1 was produced using EZ-Tn5 transposon and the mutants were inoculated into susceptible grapefruit. Forty mutants with altered virulence phenotypes were identified. Nine of the mutants showed a complete loss of citrus canker induction, and the other 31 mutants resulted in attenuated canker symptoms. Southern blot analysis revealed that each of the mutants carried a single copy of Tn5. The flanking sequence was identified by plasmid rescue and 18 different ORFs were identified in the genome sequence. Of these 18 ORFs, seven had not been previously associated with the virulence of X. citri subsp. citri and were therefore confirmed by complementation analysis. Real-time PCR analysis showed that the seven genes were upregulated when the bacteria were grown in citrus plants, suggesting that the expression of these genes was essential for canker development.
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Yaryura PM, Conforte VP, Malamud F, Roeschlin R, de Pino V, Castagnaro AP, McCarthy Y, Dow JM, Marano MR, Vojnov AA. XbmR, a new transcription factor involved in the regulation of chemotaxis, biofilm formation and virulence in Xanthomonas citri subsp. citri. Environ Microbiol 2014; 17:4164-76. [PMID: 25346091 DOI: 10.1111/1462-2920.12684] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 10/19/2014] [Indexed: 12/22/2022]
Abstract
Xanthomonas citri subsp. citri (Xcc) is the causal agent of citrus canker. Biofilm formation on citrus leaves plays an important role in epiphytic survival of Xcc. Biofilm formation is affected by transposon insertion in XAC3733, which encodes a transcriptional activator of the NtrC family, not linked to a gene encoding a sensor protein, thus could be considered as an 'orphan' regulator whose function is poorly understood in Xanthomonas spp. Here we show that mutation of XAC3733 (named xbmR) resulted in impaired structural development of the Xcc biofilm, loss of chemotaxis and reduced virulence in grapefruit plants. All defective phenotypes were restored to wild-type levels by the introduction of PA2567 from Pseudomonas aeruginosa, which encodes a phosphodiesterase active in the degradation of cyclic diguanosine monophosphate (c-di-GMP). A knockout of xbmR led to a substantial downregulation of fliA that encodes a σ(28) transcription factor, as well as fliC and XAC0350 which are potential member of the σ(28) regulon. XAC0350 encodes an HD-GYP domain c-di-GMP phosphodiesterase. These findings suggest that XbmR is a key regulator of flagellar-dependent motility and chemotaxis exerting its action through a regulatory pathway that involves FliA and c-di-GMP.
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Affiliation(s)
- Pablo M Yaryura
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Valeria P Conforte
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Florencia Malamud
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Roxana Roeschlin
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET). Área Virología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y Esmeralda, S2000FHN, Rosario, Argentina
| | - Verónica de Pino
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Atilio P Castagnaro
- Estación Experimental Agroindustrial Obispo Colombres, Av. William Cross, 3150, Las Talitas, Tucumán, Argentina
| | - Yvonne McCarthy
- School of Microbiology, University College Cork, Cork, Ireland
| | - J Maxwell Dow
- School of Microbiology, University College Cork, Cork, Ireland
| | - María R Marano
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET). Área Virología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y Esmeralda, S2000FHN, Rosario, Argentina
| | - Adrián A Vojnov
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
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Santos CR, Hoffmam ZB, de Matos Martins VP, Zanphorlin LM, de Paula Assis LH, Honorato RV, Lopes de Oliveira PS, Ruller R, Murakami MT. Molecular mechanisms associated with xylan degradation by Xanthomonas plant pathogens. J Biol Chem 2014; 289:32186-32200. [PMID: 25266726 PMCID: PMC4231694 DOI: 10.1074/jbc.m114.605105] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 09/22/2014] [Indexed: 11/06/2022] Open
Abstract
Xanthomonas pathogens attack a variety of economically relevant plants, and their xylan CUT system (carbohydrate utilization with TonB-dependent outer membrane transporter system) contains two major xylanase-related genes, xynA and xynB, which influence biofilm formation and virulence by molecular mechanisms that are still elusive. Herein, we demonstrated that XynA is a rare reducing end xylose-releasing exo-oligoxylanase and not an endo-β-1,4-xylanase as predicted. Structural analysis revealed that an insertion in the β7-α7 loop induces dimerization and promotes a physical barrier at the +2 subsite conferring this unique mode of action within the GH10 family. A single mutation that impaired dimerization became XynA active against xylan, and high endolytic activity was achieved when this loop was tailored to match a canonical sequence of endo-β-1,4-xylanases, supporting our mechanistic model. On the other hand, the divergent XynB proved to be a classical endo-β-1,4-xylanase, despite the low sequence similarity to characterized GH10 xylanases. Interestingly, this enzyme contains a calcium ion bound nearby to the glycone-binding region, which is required for catalytic activity and structural stability. These results shed light on the molecular basis for xylan degradation by Xanthomonas and suggest how these enzymes synergistically assist infection and pathogenesis. Our findings indicate that XynB contributes to breach the plant cell wall barrier, providing nutrients and facilitating the translocation of effector molecules, whereas the exo-oligoxylanase XynA possibly participates in the suppression of oligosaccharide-induced immune responses.
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Affiliation(s)
- Camila Ramos Santos
- Biosciences National Laboratory and National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil
| | - Zaira Bruna Hoffmam
- Bioethanol Science and Technology Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil
| | - Vanesa Peixoto de Matos Martins
- Biosciences National Laboratory and National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil
| | - Leticia Maria Zanphorlin
- Bioethanol Science and Technology Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil
| | - Leandro Henrique de Paula Assis
- Biosciences National Laboratory and National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil
| | - Rodrigo Vargas Honorato
- Biosciences National Laboratory and National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil
| | - Paulo Sérgio Lopes de Oliveira
- Biosciences National Laboratory and National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil
| | - Roberto Ruller
- Bioethanol Science and Technology Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil
| | - Mario Tyago Murakami
- Biosciences National Laboratory and National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil.
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Zimaro T, Thomas L, Marondedze C, Sgro GG, Garofalo CG, Ficarra FA, Gehring C, Ottado J, Gottig N. The type III protein secretion system contributes to Xanthomonas citri subsp. citri biofilm formation. BMC Microbiol 2014; 14:96. [PMID: 24742141 PMCID: PMC4021560 DOI: 10.1186/1471-2180-14-96] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 04/09/2014] [Indexed: 11/19/2022] Open
Abstract
Background Several bacterial plant pathogens colonize their hosts through the secretion of effector proteins by a Type III protein secretion system (T3SS). The role of T3SS in bacterial pathogenesis is well established but whether this system is involved in multicellular processes, such as bacterial biofilm formation has not been elucidated. Here, the phytopathogen Xanthomonas citri subsp. citri (X. citri) was used as a model to gain further insights about the role of the T3SS in biofilm formation. Results The capacity of biofilm formation of different X. citri T3SS mutants was compared to the wild type strain and it was observed that this secretion system was necessary for this process. Moreover, the T3SS mutants adhered proficiently to leaf surfaces but were impaired in leaf-associated growth. A proteomic study of biofilm cells showed that the lack of the T3SS causes changes in the expression of proteins involved in metabolic processes, energy generation, exopolysaccharide (EPS) production and bacterial motility as well as outer membrane proteins. Furthermore, EPS production and bacterial motility were also altered in the T3SS mutants. Conclusions Our results indicate a novel role for T3SS in X. citri in the modulation of biofilm formation. Since this process increases X. citri virulence, this study reveals new functions of T3SS in pathogenesis.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Natalia Gottig
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (IBR-CONICET) and Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y Esmeralda, Rosario 2000, Argentina.
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Li J, Wang N. Foliar application of biofilm formation-inhibiting compounds enhances control of citrus canker caused by Xanthomonas citri subsp. citri. PHYTOPATHOLOGY 2014; 104:134-142. [PMID: 23901828 DOI: 10.1094/phyto-04-13-0100-r] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Citrus canker caused by the bacterium Xanthomonas citri subsp. citri is an economically important disease of citrus worldwide. Biofilm formation plays an important role in early infection of X. citri subsp. citri on host leaves. In this study, we assessed the hypothesis that small molecules inhibiting biofilm formation reduce X. citri subsp. citri infection and enhance the control of citrus canker disease. D-leucine and 3-indolylacetonitrile (IAN) were found to prevent biofilm formation by X. citri subsp. citri on different abiotic surfaces and host leaves at a concentration lower than the minimum inhibitory concentration (MIC). Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis indicated that IAN repressed expression of chemotaxis/motility-related genes in X. citri subsp. citri. In laboratory experiments, planktonic and biofilm cells of X. citri subsp. citri treated with D-leucine and IAN, either alone or in combination, were more susceptible to copper (CuSO4) than those untreated. In greenhouse assays, D-leucine and IAN applied alone or combined with copper reduced both the number of canker lesions and bacterial populations of X. citri subsp. citri on citrus host leaves. This study provides the basis for the use of foliar-applied biofilm inhibitors for the control of citrus canker alone or combined with copper-based bactericides.
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Facincani AP, Moreira LM, Soares MR, Ferreira CB, Ferreira RM, Ferro MIT, Ferro JA, Gozzo FC, de Oliveira JCF. Comparative proteomic analysis reveals that T3SS, Tfp, and xanthan gum are key factors in initial stages of Citrus sinensis infection by Xanthomonas citri subsp. citri. Funct Integr Genomics 2013; 14:205-17. [PMID: 24676796 DOI: 10.1007/s10142-013-0340-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 08/18/2013] [Accepted: 09/26/2013] [Indexed: 01/02/2023]
Abstract
The bacteria Xanthomonas citri subsp. citri (Xac) is the causal agent of citrus canker. The disease symptoms are characterized by localized host cell hyperplasia followed by tissue necrosis at the infected area. An arsenal of bacterial pathogenicity- and virulence-related proteins is expressed to ensure a successful infection process. At the post-genomic stage of Xac, we used a proteomic approach to analyze the proteins that are displayed differentially over time when the pathogen attacks the host plant. Protein extracts were prepared from infectious Xac grown in inducing medium (XAM1) for 24 h or from host citrus plants for 3 or 5 days after infection, detached times to evaluate the adaptation and virulence of the pathogen. The protein extracts were proteolyzed, and the peptides derived from tryptic digestion were investigated using liquid chromatography and tandem mass spectrometry. Changes in the protein expression profile were compared with the Xac genome and the proteome recently described under non-infectious conditions. An analysis of the proteome of Xac under infectious conditions revealed proteins directly involved in virulence such as the type III secretion system (T3SS) and effector proteins (T3SS-e), the type IV pilus (Tfp), and xanthan gum biosynthesis. Moreover, four new mutants related to proteins detected in the proteome and with different functions exhibited reduced virulence relative to the wild-type proteins. The results of the proteome analysis of infectious Xac define the processes of adaptation to the host and demonstrate the induction of the virulence factors of Xac involved in plant-pathogen interactions.
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Affiliation(s)
- Agda P Facincani
- Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, Departamento de Tecnologia, UNESP-Universidade Estadual Paulista, São Paulo, SP, Brazil
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Malamud F, Homem RA, Conforte VP, Yaryura PM, Castagnaro AP, Marano MR, do Amaral AM, Vojnov AA. Identification and characterization of biofilm formation-defective mutants of Xanthomonas citri subsp. citri. Microbiology (Reading) 2013; 159:1911-1919. [DOI: 10.1099/mic.0.064709-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Florencia Malamud
- Instituto de Ciencia y Tecnología Dr César Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX Ciudad de Buenos Aires, Argentina
| | - Rafael Augusto Homem
- Embrapa Recursos Genéticos e Biotecnología and Centro APTA Citros Sylvio Moreira, Instituto Agronômico de Campinas, Cordeiropolis, Sao Pablo, Brazil
| | - Valeria Paola Conforte
- Instituto de Ciencia y Tecnología Dr César Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX Ciudad de Buenos Aires, Argentina
| | - Pablo Marcelo Yaryura
- Instituto de Ciencia y Tecnología Dr César Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX Ciudad de Buenos Aires, Argentina
| | - Atilio Pedro Castagnaro
- Estación Experimental Agroindustrial Obispo Colombres, Av. William Cross 3150, Las Talitas, Tucumán, Argentina
| | - María Rosa Marano
- IBR-Depto Microbiología, Facultad de Ciencias, Bioquímicas y Farmacéuticas, U.N.R. Suipacha 531, S2002LRK Rosario, Argentina
| | - Alexandre Morais do Amaral
- Embrapa Recursos Genéticos e Biotecnología and Centro APTA Citros Sylvio Moreira, Instituto Agronômico de Campinas, Cordeiropolis, Sao Pablo, Brazil
| | - Adrián Alberto Vojnov
- Instituto de Ciencia y Tecnología Dr César Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX Ciudad de Buenos Aires, Argentina
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Zimaro T, Thomas L, Marondedze C, Garavaglia BS, Gehring C, Ottado J, Gottig N. Insights into xanthomonas axonopodis pv. citri biofilm through proteomics. BMC Microbiol 2013; 13:186. [PMID: 23924281 PMCID: PMC3750573 DOI: 10.1186/1471-2180-13-186] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 08/02/2013] [Indexed: 11/28/2022] Open
Abstract
Background Xanthomonas axonopodis pv. citri (X. a. pv. citri) causes citrus canker that can result in defoliation and premature fruit drop with significant production losses worldwide. Biofilm formation is an important process in bacterial pathogens and several lines of evidence suggest that in X. a. pv. citri this process is a requirement to achieve maximal virulence since it has a major role in host interactions. In this study, proteomics was used to gain further insights into the functions of biofilms. Results In order to identify differentially expressed proteins, a comparative proteomic study using 2D difference gel electrophoresis was carried out on X. a. pv. citri mature biofilm and planktonic cells. The biofilm proteome showed major variations in the composition of outer membrane proteins and receptor or transport proteins. Among them, several porins and TonB-dependent receptor were differentially regulated in the biofilm compared to the planktonic cells, indicating that these proteins may serve in maintaining specific membrane-associated functions including signaling and cellular homeostasis. In biofilms, UDP-glucose dehydrogenase with a major role in exopolysaccharide production and the non-fimbrial adhesin YapH involved in adherence were over-expressed, while a polynucleotide phosphorylase that was demonstrated to negatively control biofilm formation in E. coli was down-regulated. In addition, several proteins involved in protein synthesis, folding and stabilization were up-regulated in biofilms. Interestingly, some proteins related to energy production, such as ATP-synthase were down-regulated in biofilms. Moreover, a number of enzymes of the tricarboxylic acid cycle were differentially expressed. In addition, X. a. pv. citri biofilms also showed down-regulation of several antioxidant enzymes. The respective gene expression patterns of several identified proteins in both X. a. pv. citri mature biofilm and planktonic cells were evaluated by quantitative real-time PCR and shown to consistently correlate with those deduced from the proteomic study. Conclusions Differentially expressed proteins are enriched in functional categories. Firstly, proteins that are down-regulated in X. a. pv. citri biofilms are enriched for the gene ontology (GO) terms ‘generation of precursor metabolites and energy’ and secondly, the biofilm proteome mainly changes in ‘outer membrane and receptor or transport’. We argue that the differentially expressed proteins have a critical role in maintaining a functional external structure as well as enabling appropriate flow of nutrients and signals specific to the biofilm lifestyle.
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Affiliation(s)
- Tamara Zimaro
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (IBR-CONICET), Ocampo y Esmeralda, Rosario, Santa Fe, Argentina
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49
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Bogino PC, de las Mercedes Oliva M, Sorroche FG, Giordano W. The role of bacterial biofilms and surface components in plant-bacterial associations. Int J Mol Sci 2013; 14:15838-59. [PMID: 23903045 PMCID: PMC3759889 DOI: 10.3390/ijms140815838] [Citation(s) in RCA: 216] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 06/18/2013] [Accepted: 06/28/2013] [Indexed: 01/09/2023] Open
Abstract
The role of bacterial surface components in combination with bacterial functional signals in the process of biofilm formation has been increasingly studied in recent years. Plants support a diverse array of bacteria on or in their roots, transport vessels, stems, and leaves. These plant-associated bacteria have important effects on plant health and productivity. Biofilm formation on plants is associated with symbiotic and pathogenic responses, but how plants regulate such associations is unclear. Certain bacteria in biofilm matrices have been found to induce plant growth and to protect plants from phytopathogens (a process termed biocontrol), whereas others are involved in pathogenesis. In this review, we systematically describe the various components and mechanisms involved in bacterial biofilm formation and attachment to plant surfaces and the relationships of these mechanisms to bacterial activity and survival.
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Affiliation(s)
- Pablo C. Bogino
- Department of Molecular Biology, National University of Río Cuarto, Ruta 36 Km 601, Río Cuarto, Córdoba X5804BYA, Argentina; E-Mails: (P.C.B.); (F.G.S.)
| | - María de las Mercedes Oliva
- Department of Microbiology and Immunology, National University of Río Cuarto, Ruta 36 Km 601, Córdoba X5804BYA, Argentina; E-Mail:
| | - Fernando G. Sorroche
- Department of Molecular Biology, National University of Río Cuarto, Ruta 36 Km 601, Río Cuarto, Córdoba X5804BYA, Argentina; E-Mails: (P.C.B.); (F.G.S.)
| | - Walter Giordano
- Department of Molecular Biology, National University of Río Cuarto, Ruta 36 Km 601, Río Cuarto, Córdoba X5804BYA, Argentina; E-Mails: (P.C.B.); (F.G.S.)
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50
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Huang TP, Lu KM, Chen YH. A novel two-component response regulator links rpf with biofilm formation and virulence of Xanthomonas axonopodis pv. citri. PLoS One 2013; 8:e62824. [PMID: 23626857 PMCID: PMC3633832 DOI: 10.1371/journal.pone.0062824] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 03/26/2013] [Indexed: 11/18/2022] Open
Abstract
Citrus bacterial canker caused by Xanthomonas axonopodis pv. citri is a serious disease that impacts citrus production worldwide, and X. axonopodis pv. citri is listed as a quarantine pest in certain countries. Biofilm formation is important for the successful development of a pathogenic relationship between various bacteria and their host(s). To understand the mechanisms of biofilm formation by X. axonopodis pv. citri strain XW19, the strain was subjected to transposon mutagenesis. One mutant with a mutation in a two-component response regulator gene that was deficient in biofilm formation on a polystyrene microplate was selected for further study. The protein was designated as BfdR for biofilm formation defective regulator. BfdR from strain XW19 shares 100% amino acid sequence identity with XAC1284 of X. axonopodis pv. citri strain 306 and 30-100% identity with two-component response regulators in various pathogens and environmental microorganisms. The bfdR mutant strain exhibited significantly decreased biofilm formation on the leaf surfaces of Mexican lime compared with the wild type strain. The bfdR mutant was also compromised in its ability to cause canker lesions. The wild-type phenotype was restored by providing pbfdR in trans in the bfdR mutant. Our data indicated that BfdR did not regulate the production of virulence-related extracellular enzymes including amylase, lipase, protease, and lecithinase or the expression of hrpG, rfbC, and katE; however, BfdR controlled the expression of rpfF in XVM2 medium, which mimics cytoplasmic fluids in planta. In conclusion, biofilm formation on leaf surfaces of citrus is important for canker development in X. axonopodis pv. citri XW19. The process is controlled by the two-component response regulator BfdR via regulation of rpfF, which is required for the biosynthesis of a diffusible signal factor.
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Affiliation(s)
- Tzu-Pi Huang
- Department of Plant Pathology, National Chung-Hsing University, Taichung, Taiwan.
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