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Chen X, Zou H, Zhuo T, Rou W, Wu W, Fan X. Xanthomonas citri subsp. citri type III effector PthA4 directs the dynamical expression of a putative citrus carbohydrate-binding protein gene for canker formation. eLife 2024; 13:RP91684. [PMID: 39136681 PMCID: PMC11321762 DOI: 10.7554/elife.91684] [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] [Indexed: 08/15/2024] Open
Abstract
Xanthomonas citri subsp. citri (Xcc), the causal agent of citrus canker, elicits canker symptoms in citrus plants because of the transcriptional activator-like (TAL) effector PthA4, which activates the expression of the citrus susceptibility gene CsLOB1. This study reports the regulation of the putative carbohydrate-binding protein gene Cs9g12620 by PthA4-mediated induction of CsLOB1 during Xcc infection. We found that the transcription of Cs9g12620 was induced by infection with Xcc in a PthA4-dependent manner. Even though it specifically bound to a putative TAL effector-binding element in the Cs9g12620 promoter, PthA4 exerted a suppressive effect on the promoter activity. In contrast, CsLOB1 bound to the Cs9g12620 promoter to activate its expression. The silencing of CsLOB1 significantly reduced the level of expression of Cs9g12620, which demonstrated that Cs9g12620 was directly regulated by CsLOB1. Intriguingly, PhtA4 interacted with CsLOB1 and exerted feedback control that suppressed the induction of expression of Cs9g12620 by CsLOB1. Transient overexpression and gene silencing revealed that Cs9g12620 was required for the optimal development of canker symptoms. These results support the hypothesis that the expression of Cs9g12620 is dynamically directed by PthA4 for canker formation through the PthA4-mediated induction of CsLOB1.
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Affiliation(s)
- Xinyu Chen
- Plant Protection College, Fujian Agriculture and Forestry UniversityFuzhouChina
| | - Huasong Zou
- School of Life Sciences and Health, Huzhou CollegeHuzhouChina
| | - Tao Zhuo
- Plant Protection College, Fujian Agriculture and Forestry UniversityFuzhouChina
| | - Wei Rou
- Plant Protection College, Fujian Agriculture and Forestry UniversityFuzhouChina
| | - Wei Wu
- Plant Protection College, Fujian Agriculture and Forestry UniversityFuzhouChina
| | - Xiaojing Fan
- Plant Protection College, Fujian Agriculture and Forestry UniversityFuzhouChina
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Horton KN, Gassmann W. Greater than the sum of their parts: an overview of the AvrRps4 effector family. FRONTIERS IN PLANT SCIENCE 2024; 15:1400659. [PMID: 38799092 PMCID: PMC11116571 DOI: 10.3389/fpls.2024.1400659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Accepted: 04/26/2024] [Indexed: 05/29/2024]
Abstract
Phytopathogenic microbes use secreted effector proteins to increase their virulence in planta. If these effectors or the results of their activity are detected by the plant cell, the plant will mount an immune response which applies evolutionary pressure by reducing growth and success of the pathogen. Bacterial effector proteins in the AvrRps4 family (AvrRps4, HopK1, and XopO) have commonly been used as tools to investigate plant immune components. At the same time, the in planta functions of this family of effectors have yet to be fully characterized. In this minireview we summarize current knowledge about the AvrRps4 effector family with emphasis on properties of the proteins themselves. We hypothesize that the HopK1 C-terminus and the AvrRps4 C-terminus, though unrelated in sequence and structure, are broadly related in functions that counteract plant defense responses.
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Affiliation(s)
| | - Walter Gassmann
- Division of Plant Science and Technology, Bond Life Sciences Center, and Interdisciplinary Plant Group, University of Missouri, Columbia, MO, United States
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Xu J, Zhang Y, Li J, Teper D, Sun X, Jones D, Wang Y, Tao J, Goss EM, Jones JB, Wang N. Phylogenomic analysis of 343 Xanthomonas citri pv. citri strains unravels introduction history and dispersal paths. PLoS Pathog 2023; 19:e1011876. [PMID: 38100539 PMCID: PMC10756548 DOI: 10.1371/journal.ppat.1011876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 12/29/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023] Open
Abstract
Xanthomonas citri pv. citri (Xcc) causes the devastating citrus canker disease. Xcc is known to have been introduced into Florida, USA in at least three different events in 1915, 1986 and 1995 with the first two claimed to be eradicated. It was questioned whether the Xcc introduction in 1986 has been successfully eradicated. Furthermore, it is unknown how Xcc has spread throughout the citrus groves in Florida. In this study, we investigated the population structure of Xcc to address these questions. We sequenced the whole genome of 343 Xcc strains collected from Florida groves between 1997 and 2016. Our analysis revealed two distinct clusters of Xcc. Our data strongly indicate that the claimed eradication of the 1986 Xcc introduction was not successful and Xcc strains from 1986 introduction were present in samples from at least 8 counties collected after 1994. Importantly, our data revealed that the Cluster 2 strains, which are present in all 20 citrus-producing counties sampled in Florida, originated from the Xcc introduction event in the Miami area in 1995. Our data suggest that Polk County is the epicenter of the dispersal of Cluster 2 Xcc strains, which is consistent with the fact that three major hurricanes passed through Polk County in 2004. As copper-based products have been extensively used to control citrus canker, we also investigated whether Xcc strains have developed resistance to copper. Notably, none of the 343 strains contained known copper resistance genes. Twenty randomly selected Xcc strains displayed sensitivity to copper. Overall, this study provides valuable insights into the introduction, eradication, spread, and copper resistance of Xcc in Florida.
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Affiliation(s)
- Jin Xu
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, Florida, United States of America
| | - Yanan Zhang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, Florida, United States of America
| | - Jinyun Li
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, Florida, United States of America
| | - Doron Teper
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, Florida, United States of America
| | - Xiaoan Sun
- Florida Department of Agriculture and Consumer Services, Gainesville, Florida, United States of America
| | - Debra Jones
- Florida Department of Agriculture and Consumer Services, Gainesville, Florida, United States of America
| | - Yayu Wang
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, China
| | - Jin Tao
- Guangdong Magigene Biotechnology Co., Ltd., Guangzhou, China
| | - Erica M. Goss
- Department of Plant Pathology, IFAS, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Jeffrey B. Jones
- Department of Plant Pathology, IFAS, University of Florida, Gainesville, Florida, United States of America
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, Florida, United States of America
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Campos PE, Pruvost O, Boyer K, Chiroleu F, Cao TT, Gaudeul M, Baider C, Utteridge TMA, Becker N, Rieux A, Gagnevin L. Herbarium specimen sequencing allows precise dating of Xanthomonas citri pv. citri diversification history. Nat Commun 2023; 14:4306. [PMID: 37474518 PMCID: PMC10359311 DOI: 10.1038/s41467-023-39950-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 06/15/2023] [Indexed: 07/22/2023] Open
Abstract
Herbarium collections are an important source of dated, identified and preserved DNA, whose use in comparative genomics and phylogeography can shed light on the emergence and evolutionary history of plant pathogens. Here, we reconstruct 13 historical genomes of the bacterial crop pathogen Xanthomonas citri pv. citri (Xci) from infected Citrus herbarium specimens. Following authentication based on ancient DNA damage patterns, we compare them with a large set of modern genomes to estimate their phylogenetic relationships, pathogenicity-associated gene content and several evolutionary parameters. Our results indicate that Xci originated in Southern Asia ~11,500 years ago (perhaps in relation to Neolithic climate change and the development of agriculture) and diversified during the beginning of the 13th century, after Citrus diversification and before spreading to the rest of the world (probably via human-driven expansion of citriculture through early East-West trade and colonization).
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Affiliation(s)
- Paola E Campos
- CIRAD, UMR PVBMT, F-97410, St Pierre, La Réunion, France
- Institut de Systématique, Évolution, Biodiversité (ISyEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, 57 rue Cuvier, CP 50, 75005, Paris, France
| | | | - Karine Boyer
- CIRAD, UMR PVBMT, F-97410, St Pierre, La Réunion, France
| | | | - Thuy Trang Cao
- CIRAD, UMR PVBMT, F-97410, St Pierre, La Réunion, France
| | - Myriam Gaudeul
- Institut de Systématique, Évolution, Biodiversité (ISyEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, 57 rue Cuvier, CP 50, 75005, Paris, France
- Herbier national, Muséum national d'Histoire naturelle, CP39, 57 rue Cuvier, 75005, Paris, France
| | - Cláudia Baider
- The Mauritius Herbarium, Agricultural Services, Ministry of Agro-Industry and Food Security, R.E. Vaughan Building (MSIRI Compound), Reduit, 80835, Mauritius
| | | | - Nathalie Becker
- Institut de Systématique, Évolution, Biodiversité (ISyEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, 57 rue Cuvier, CP 50, 75005, Paris, France
| | - Adrien Rieux
- CIRAD, UMR PVBMT, F-97410, St Pierre, La Réunion, France.
| | - Lionel Gagnevin
- PHIM Plant Health Institute, Univ. Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France.
- CIRAD, UMR PHIM, Montpellier, France.
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Wagner N, Ben-Meir D, Teper D, Pupko T. Complete genome sequence of an Israeli isolate of Xanthomonas hortorum pv. pelargonii strain 305 and novel type III effectors identified in Xanthomonas. FRONTIERS IN PLANT SCIENCE 2023; 14:1155341. [PMID: 37332699 PMCID: PMC10275491 DOI: 10.3389/fpls.2023.1155341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 05/10/2023] [Indexed: 06/20/2023]
Abstract
Xanthomonas hortorum pv. pelargonii is the causative agent of bacterial blight in geranium ornamental plants, the most threatening bacterial disease of this plant worldwide. Xanthomonas fragariae is the causative agent of angular leaf spot in strawberries, where it poses a significant threat to the strawberry industry. Both pathogens rely on the type III secretion system and the translocation of effector proteins into the plant cells for their pathogenicity. Effectidor is a freely available web server we have previously developed for the prediction of type III effectors in bacterial genomes. Following a complete genome sequencing and assembly of an Israeli isolate of Xanthomonas hortorum pv. pelargonii - strain 305, we used Effectidor to predict effector encoding genes both in this newly sequenced genome, and in X. fragariae strain Fap21, and validated its predictions experimentally. Four and two genes in X. hortorum and X. fragariae, respectively, contained an active translocation signal that allowed the translocation of the reporter AvrBs2 that induced the hypersensitive response in pepper leaves, and are thus considered validated novel effectors. These newly validated effectors are XopBB, XopBC, XopBD, XopBE, XopBF, and XopBG.
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Affiliation(s)
- Naama Wagner
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Daniella Ben-Meir
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Doron Teper
- Department of Plant Pathology and Weed Research, Institute of Plant Protection Agricultural Research Organization (ARO), Volcani Institute, Rishon LeZion, Israel
| | - Tal Pupko
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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Shahbaz E, Ali M, Shafiq M, Atiq M, Hussain M, Balal RM, Sarkhosh A, Alferez F, Sadiq S, Shahid MA. Citrus Canker Pathogen, Its Mechanism of Infection, Eradication, and Impacts. PLANTS (BASEL, SWITZERLAND) 2022; 12:plants12010123. [PMID: 36616252 PMCID: PMC9824702 DOI: 10.3390/plants12010123] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/14/2022] [Accepted: 12/13/2022] [Indexed: 05/16/2023]
Abstract
Citrus canker is a ravaging bacterial disease threatening citrus crops. Its major types are Asiatic Canker, Cancrosis B, and Cancrosis C, caused by Xanthomonas citri pv. citri (Xcc), Xanthomonas citri pv. aurantifolii pathotype-B (XauB), and pathotype-C (XauC), respectively. The bacterium enters its host through stomata and wounds, from which it invades the intercellular spaces in the apoplast. It produces erumpent corky necrotic lesions often surrounded by a chlorotic halo on the leaves, young stems, and fruits, which causes dark spots, defoliation, reduced photosynthetic rate, rupture of leaf epidermis, dieback, and premature fruit drop in severe cases. Its main pathogenicity determinant gene is pthA, whose variants are present in all citrus canker-causing pathogens. Countries where citrus canker is not endemic adopt different methods to prevent the introduction of the pathogen into the region, eradicate the pathogen, and minimize its dissemination, whereas endemic regions require an integrated management program to control the disease. The main aim of the present manuscript is to shed light on the pathogen profile, its mechanism of infection, and fruitful strategies for disease management. Although an adequate method to completely eradicate citrus canker has not been introduced so far, many new methods are under research to abate the disease.
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Affiliation(s)
- Esha Shahbaz
- Department of Food Sciences, Faculty of Agricultural Sciences, University of the Punjab, Lahore 54590, Pakistan
| | - Mobeen Ali
- Department of Horticulture, Faculty of Agricultural Sciences, University of the Punjab, Lahore 54590, Pakistan
| | - Muhammad Shafiq
- Department of Horticulture, Faculty of Agricultural Sciences, University of the Punjab, Lahore 54590, Pakistan
| | - Muhammad Atiq
- Department of Plant Pathology, University of Agriculture, Faisalabad 38000, Pakistan
| | - Mujahid Hussain
- Horticultural Science Department, North Florida Research and Education Center, University of Florida/IFAS, Quincy, FL 32351, USA
| | - Rashad Mukhtar Balal
- Department of Horticulture, College of Agriculture, University of Sargodha, Sargodha 40100, Pakistan
| | - Ali Sarkhosh
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA
| | - Fernando Alferez
- Horticultural Science Department, Southwest Florida Research and Education Center, University of Florida/IFAS, Immokalee, FL 34142, USA
| | - Saleha Sadiq
- Department of Horticulture, Faculty of Agricultural Sciences, University of the Punjab, Lahore 54590, Pakistan
| | - Muhammad Adnan Shahid
- Horticultural Science Department, North Florida Research and Education Center, University of Florida/IFAS, Quincy, FL 32351, USA
- Correspondence:
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An Extracytoplasmic Function Sigma Factor Required for Full Virulence in Xanthomonas citri pv. citri. J Bacteriol 2022; 204:e0062421. [PMID: 35446118 DOI: 10.1128/jb.00624-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genus Xanthomonas includes more than 30 phytopathogenic species that infect a wide range of plants and cause severe diseases that greatly impact crop productivity. These bacteria are highly adapted to the soil and plant environment, being found in decaying material, as epiphytes, and colonizing the plant mesophyll. Signal transduction mechanisms involved in the responses of Xanthomonas to environmental changes are still poorly characterized. Xanthomonad genomes typically encode several representatives of the extracytoplasmic function σ (σECF) factors, whose physiological roles remain elusive. In this work, we functionally characterized the Xanthomonas citri pv. citri EcfL, a σECF factor homologous to members of the iron-responsive FecI-like group. We show that EcfL is not required or induced during iron starvation, despite presenting the common features of other FecI-like σECF factors. EcfL positively regulates one operon composed of three genes that encode a TonB-dependent receptor involved in cell surface signaling, an acid phosphatase, and a lectin-domain containing protein. Furthermore, we demonstrate that EcfL is required for full virulence in citrus, and its regulon is induced inside the plant mesophyll and in response to acid stress. Together, our study suggests a role for EcfL in the adaptation of X. citri to the plant environment, in this way contributing to its ability to cause citrus canker disease. IMPORTANCE The Xanthomonas genus comprises a large number of phytopathogenic species that infect a wide variety of economically important plants worldwide. Bacterial adaptation to the plant and soil environment relies on their repertoire of signal transduction pathways, including alternative sigma factors of the extracytoplasmic function family (σECF). Here, we describe a new σECF factor found in several Xanthomonas species, demonstrating its role in Xanthomonas citri virulence to citrus plants. We show that EcfL regulates a single operon containing three genes, which are also conserved in other Xanthomonas species. This study further expands our knowledge on the functions of the widespread family of σECF factors in phytopathogenic bacteria.
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Rosenthal E, Potnis N, Bull CT. Comparative Genomic Analysis of the Lettuce Bacterial Leaf Spot Pathogen, Xanthomonas hortorum pv. vitians, to Investigate Race Specificity. Front Microbiol 2022; 13:840311. [PMID: 35516433 PMCID: PMC9062649 DOI: 10.3389/fmicb.2022.840311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 02/09/2022] [Indexed: 01/01/2023] Open
Abstract
Bacterial leaf spot (BLS) of lettuce caused by Xanthomonas hortorum pv. vitians (Xhv) was first described over 100 years ago and remains a significant threat to lettuce cultivation today. This study investigated the genetic relatedness of the Xhv strains and the possible genetic sources of this race-specific pathogenicity. Whole genome sequences of eighteen Xhv strains representing the three races, along with eight related Xanthomonas strains, were included in the analysis. A maximum likelihood phylogeny based on concatenated whole genome SNPs confirmed previous results describing two major lineages of Xhv strains. Gene clusters encoding secretion systems, secondary metabolites, and bacteriocins were assessed to identify putative virulence factors that distinguish the Xhv races. Genome sequences were mined for effector genes, which have been shown to be involved in race specificity in other systems. Two effectors identified in this study, xopAQ and the novel variant xopAF2, were revealed as possible mediators of a gene-for-gene interaction between Xhv race 1 and 3 strains and wild lettuce Lactuca serriola ARM-09-161-10-1. Transposase sequence identified downstream of xopAF2 and prophage sequence found nearby within Xhv race 1 and 3 insertion sequences suggest that this gene may have been acquired through phage-mediated gene transfer. No other factors were identified from these analyses that distinguish the Xhv races.
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Affiliation(s)
- Emma Rosenthal
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA, United States
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States
| | - Carolee T Bull
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA, United States
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9
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Wagner N, Avram O, Gold-Binshtok D, Zerah B, Teper D, Pupko T. Effectidor: an automated machine-learning-based web server for the prediction of type-III secretion system effectors. Bioinformatics 2022; 38:2341-2343. [PMID: 35157036 DOI: 10.1093/bioinformatics/btac087] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 01/31/2022] [Accepted: 02/08/2022] [Indexed: 02/03/2023] Open
Abstract
MOTIVATION Type-III secretion systems are utilized by many Gram-negative bacteria to inject type-3 effectors (T3Es) to eukaryotic cells. These effectors manipulate host processes for the benefit of the bacteria and thus promote disease. They can also function as host-specificity determinants through their recognition as avirulence proteins that elicit immune response. Identifying the full effector repertoire within a set of bacterial genomes is of great importance to develop appropriate treatments against the associated pathogens. RESULTS We present Effectidor, a user-friendly web server that harnesses several machine-learning techniques to predict T3Es within bacterial genomes. We compared the performance of Effectidor to other available tools for the same task on three pathogenic bacteria. Effectidor outperformed these tools in terms of classification accuracy (area under the precision-recall curve above 0.98 in all cases). AVAILABILITY AND IMPLEMENTATION Effectidor is available at: https://effectidor.tau.ac.il, and the source code is available at: https://github.com/naamawagner/Effectidor. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Naama Wagner
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Oren Avram
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Dafna Gold-Binshtok
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ben Zerah
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Doron Teper
- Department of Plant Pathology and Weed Research, Institute of Plant Protection Agricultural Research Organization (ARO), Volcani Center, Rishon LeZion 7505101, Israel
| | - Tal Pupko
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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10
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Luneau JS, Cerutti A, Roux B, Carrère S, Jardinaud M, Gaillac A, Gris C, Lauber E, Berthomé R, Arlat M, Boulanger A, Noël LD. Xanthomonas transcriptome inside cauliflower hydathodes reveals bacterial virulence strategies and physiological adaptations at early infection stages. MOLECULAR PLANT PATHOLOGY 2022; 23:159-174. [PMID: 34837293 PMCID: PMC8743013 DOI: 10.1111/mpp.13117] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/22/2021] [Accepted: 07/22/2021] [Indexed: 06/01/2023]
Abstract
Xanthomonas campestris pv. campestris (Xcc) is a seed-transmitted vascular pathogen causing black rot disease on cultivated and wild Brassicaceae. Xcc enters the plant tissues preferentially via hydathodes, which are organs localized at leaf margins. To decipher both physiological and virulence strategies deployed by Xcc during early stages of infection, the transcriptomic profile of Xcc was analysed 3 days after entry into cauliflower hydathodes. Despite the absence of visible plant tissue alterations and despite a biotrophic lifestyle, 18% of Xcc genes were differentially expressed, including a striking repression of chemotaxis and motility functions. The Xcc full repertoire of virulence factors had not yet been activated but the expression of the HrpG regulon composed of 95 genes, including genes coding for the type III secretion machinery important for suppression of plant immunity, was induced. The expression of genes involved in metabolic adaptations such as catabolism of plant compounds, transport functions, sulphur and phosphate metabolism was upregulated while limited stress responses were observed 3 days postinfection. We confirmed experimentally that high-affinity phosphate transport is needed for bacterial fitness inside hydathodes. This analysis provides information about the nutritional and stress status of bacteria during the early biotrophic infection stages and helps to decipher the adaptive strategy of Xcc to the hydathode environment.
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Affiliation(s)
- Julien S. Luneau
- LIPME, Université de Toulouse, INRAE, CNRS, Université Paul SabatierCastanet‐TolosanFrance
| | - Aude Cerutti
- LIPME, Université de Toulouse, INRAE, CNRS, Université Paul SabatierCastanet‐TolosanFrance
| | - Brice Roux
- LIPME, Université de Toulouse, INRAE, CNRS, Université Paul SabatierCastanet‐TolosanFrance
- Present address:
Brice Roux, HalioDx, Luminy Biotech EntreprisesMarseille Cedex 9France
| | - Sébastien Carrère
- LIPME, Université de Toulouse, INRAE, CNRS, Université Paul SabatierCastanet‐TolosanFrance
| | | | - Antoine Gaillac
- LIPME, Université de Toulouse, INRAE, CNRS, Université Paul SabatierCastanet‐TolosanFrance
| | - Carine Gris
- LIPME, Université de Toulouse, INRAE, CNRS, Université Paul SabatierCastanet‐TolosanFrance
| | - Emmanuelle Lauber
- LIPME, Université de Toulouse, INRAE, CNRS, Université Paul SabatierCastanet‐TolosanFrance
| | - Richard Berthomé
- LIPME, Université de Toulouse, INRAE, CNRS, Université Paul SabatierCastanet‐TolosanFrance
| | - Matthieu Arlat
- LIPME, Université de Toulouse, INRAE, CNRS, Université Paul SabatierCastanet‐TolosanFrance
| | - Alice Boulanger
- LIPME, Université de Toulouse, INRAE, CNRS, Université Paul SabatierCastanet‐TolosanFrance
| | - Laurent D. Noël
- LIPME, Université de Toulouse, INRAE, CNRS, Université Paul SabatierCastanet‐TolosanFrance
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11
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Yang P, Chang Y, Wang L, Wang S, Wu J. Regulatory Mechanisms of the Resistance to Common Bacterial Blight Revealed by Transcriptomic Analysis in Common Bean ( Phaseolus vulgaris L.). FRONTIERS IN PLANT SCIENCE 2022; 12:800535. [PMID: 35069659 PMCID: PMC8767069 DOI: 10.3389/fpls.2021.800535] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 12/14/2021] [Indexed: 05/16/2023]
Abstract
Common bean blight (CBB), primarily caused by Xanthomonas axonopodis pv. phaseoli (Xap), is one of the most destructive diseases of common bean (Phaseolus vulgaris L.). The tepary bean genotype PI 319443 displays high resistance to Xap, and the common bean genotypes HR45 and Bilu display high resistance and susceptibility to Xap, respectively. To identify candidate genes related to Xap resistance, transcriptomic analysis was performed to compare gene expression levels with Xap inoculation at 0, 24, and 48 h post inoculation (hpi) among the three genotypes. A total of 1,146,009,876 high-quality clean reads were obtained. Differentially expressed gene (DEG) analysis showed that 1,688 DEGs responded to pathogen infection in the three genotypes. Weighted gene coexpression network analysis (WGCNA) was also performed to identify three modules highly correlated with Xap resistance, in which 334 DEGs were likely involved in Xap resistance. By combining differential expression analysis and WGCNA, 139 DEGs were identified as core resistance-responsive genes, including 18 genes encoding resistance (R) proteins, 19 genes belonging to transcription factor families, 63 genes encoding proteins with oxidoreductase activity, and 33 plant hormone signal transduction-related genes, which play important roles in the resistance to pathogen infection. The expression patterns of 20 DEGs were determined by quantitative real-time PCR (qRT-PCR) and confirmed the reliability of the RNA-seq results.
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Affiliation(s)
| | | | | | | | - Jing Wu
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
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12
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Cohn AR, Orsi RH, Carroll LM, Chen R, Wiedmann M, Cheng RA. Characterization of Basal Transcriptomes Identifies Potential Metabolic and Virulence-Associated Adaptations Among Diverse Nontyphoidal Salmonella enterica Serovars. Front Microbiol 2021; 12:730411. [PMID: 34721328 PMCID: PMC8552914 DOI: 10.3389/fmicb.2021.730411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 08/30/2021] [Indexed: 01/18/2023] Open
Abstract
The zoonotic pathogen Salmonella enterica includes >2,600 serovars, which differ in the range of hosts they infect and the severity of disease they cause. To further elucidate the mechanisms behind these differences, we performed transcriptomic comparisons of nontyphoidal Salmonella (NTS) serovars with the model for NTS pathogenesis, S. Typhimurium. Specifically, we used RNA-seq to characterize the understudied NTS serovars S. Javiana and S. Cerro, representing a serovar frequently attributed to human infection via contact with amphibians and reptiles, and a serovar primarily associated with cattle, respectively. Whole-genome sequence (WGS) data were utilized to ensure that strains characterized with RNA-seq were representative of their respective serovars. RNA extracted from representative strains of each serovar grown to late exponential phase in Luria-Bertani (LB) broth showed that transcript abundances of core genes were significantly higher (p<0.001) than those of accessory genes for all three serovars. Inter-serovar comparisons identified that transcript abundances of genes in Salmonella Pathogenicity Island (SPI) 1 were significantly higher in both S. Javiana and S. Typhimurium compared to S. Cerro. Together, our data highlight potential transcriptional mechanisms that may facilitate S. Cerro and S. Javiana survival in and adaptation to their respective hosts and impact their ability to cause disease in others. Furthermore, our analyses demonstrate the utility of omics approaches in advancing our understanding of the diversity of metabolic and virulence mechanisms of different NTS serovars.
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Affiliation(s)
- Alexa R Cohn
- Department of Microbiology, Cornell University, Ithaca, NY, United States
| | - Renato H Orsi
- Department of Food Science, Cornell University, Ithaca, NY, United States
| | - Laura M Carroll
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Ruixi Chen
- Department of Food Science, Cornell University, Ithaca, NY, United States
| | - Martin Wiedmann
- Department of Food Science, Cornell University, Ithaca, NY, United States
| | - Rachel A Cheng
- Department of Food Science, Cornell University, Ithaca, NY, United States
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13
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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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14
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Ribeiro C, Xu J, Teper D, Lee D, Wang N. The transcriptome landscapes of citrus leaf in different developmental stages. PLANT MOLECULAR BIOLOGY 2021; 106:349-366. [PMID: 33871796 DOI: 10.1007/s11103-021-01154-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 04/12/2021] [Indexed: 06/12/2023]
Abstract
The temporal expression profiles of citrus leaves explain the sink-source transition of immature leaves to mature leaves and provide knowledge regarding the differential responses of mature and immature leaves to biotic stress such as citrus canker and Asian citrus psyllid (Diaphorina citri). Citrus is an important fruit crop worldwide. Different developmental stages of citrus leaves are associated with distinct features, such as differences in susceptibilities to pathogens and insects, as well as photosynthetic capacity. Here, we investigated the mechanisms underlying these distinctions by comparing the gene expression profiles of mature and immature citrus leaves. Immature (stages V3 and V4), transition (stage V5), and mature (stage V6) Citrus sinensis leaves were chosen for RNA-seq analyses. Carbohydrate biosynthesis, photosynthesis, starch biosynthesis, and disaccharide metabolic processes were enriched among the upregulated differentially expressed genes (DEGs) in the V5 and V6 stages compared with that in the V3 and V4 stages. Glucose level was found to be higher in V5 and V6 than in V3 and V4. Among the four stages, the largest number of DEGs between contiguous stages were identified between V5 and V4, consistent with a change from sink to source, as well as with the sucrose and starch quantification data. The differential expression profiles related to cell wall synthesis, secondary metabolites such as flavonoids and terpenoids, amino acid biosynthesis, and immunity between immature and mature leaves may contribute to their different responses to Asian citrus psyllid infestation. The expression data suggested that both the constitutive and induced gene expression of immunity-related genes plays important roles in the greater resistance of mature leaves against Xanthomonas citri compared with immature leaves. The gene expression profiles in the different stages can help identify stage-specific promoters for the manipulation of the expression of citrus traits according to the stage. The temporal expression profiles explain the sink-source transition of immature leaves to mature leaves and provide knowledge regarding the differential responses to biotic stress.
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Affiliation(s)
- Camila Ribeiro
- Citrus Research & Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences (IFAS), University of Florida, Lake Alfred, FL, 33850, USA
| | - Jin Xu
- Citrus Research & Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences (IFAS), University of Florida, Lake Alfred, FL, 33850, USA
| | - Doron Teper
- Citrus Research & Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences (IFAS), University of Florida, Lake Alfred, FL, 33850, USA
| | - Donghwan Lee
- Citrus Research & Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences (IFAS), University of Florida, Lake Alfred, FL, 33850, USA
| | - Nian Wang
- Citrus Research & Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences (IFAS), University of Florida, Lake Alfred, FL, 33850, USA.
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15
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Phytochemical Screening and Evaluation of Antioxidant Properties and Antimicrobial Activity against Xanthomonas axonopodis of Euphorbia tirucalli Extracts in Binh Thuan Province, Vietnam. Molecules 2021; 26:molecules26040941. [PMID: 33578946 PMCID: PMC7916649 DOI: 10.3390/molecules26040941] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/02/2021] [Accepted: 02/02/2021] [Indexed: 11/16/2022] Open
Abstract
Euphorbia tirucalli is a medicine plant possessing many bioactive properties. This paper focused on phytochemical screening (alkaloid, flavonoid, saponin, tannin, and anthraquinone), quantification of polyphenol and flavonoids, and activating evaluation of antioxidants and antimicrobial properties against Xanthomonas axonopodis of different extracts from Euphorbia tirucalli grown in Binh Thuan, Vietnam. The best activity fraction was used for purification and determining bioactive ingredients. The results showed that the phytochemical study revealed the presence of alkaloids, flavonoids, tannins, and terpenoids in the ethyl acetate fraction. Saponin and anthraquinone did not present in all extracts. The content of polyphenol and flavonoid of Euphorbia tirucalli stem was in the range of 16.65–106.32 mg EqAG/g and 97.97–450.83 μg QE/g. The ethyl acetate fraction showed higher amounts of polyphenol and flavonoids and antimicrobial activity against X. axonopodis than other fractions. The antioxidant (SC50) activity of Euphorbia tirucalli stem was in the range of 12.91 ± 0.70 and 528.33 ± 25.15 μg/mL. At concentrations of 5.0 and 7.5 mg/mL, the diameter of inhibition of the ethyl acetate fraction was 14.33 ± 0.76 mm and 17.87 ± 0.57 mm, respectively. The MIC (minimum inhibitory concentration) was 0.156 mg/mL. Scopoletin, gallic acid, and piperic acid got MICs corresponding to 78, 312, and 312 μg/mL, respectively. Scopoletin, gallic acid, and piperic acid were found in the ethyl acetate fraction of Euphorbia tirucalli and exhibited the treatment of citrus bacteria canker and plant diseases.
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16
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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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Toxin-Antitoxin Gene Pairs Found in Tn 3 Family Transposons Appear To Be an Integral Part of the Transposition Module. mBio 2020; 11:mBio.00452-20. [PMID: 32234815 PMCID: PMC7157771 DOI: 10.1128/mbio.00452-20] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Transposable elements (TEs) are important in genetic diversification due to their recombination properties and their ability to promote horizontal gene transfer. Over the last decades, much effort has been made to understand TE transposition mechanisms and their impact on prokaryotic genomes. For example, the Tn3 family is ubiquitous in bacteria, molding their host genomes by the paste-and-copy mechanism. In addition to the transposition module, Tn3 members often carry additional passenger genes (e.g., conferring antibiotic or heavy metal resistance and virulence), and three were previously known to carry a toxin-antitoxin (TA) system often associated with plasmid maintenance; however, the role of TA systems within the Tn3 family is unknown. The genetic context of TA systems in Tn3 members suggests that they may play a regulatory role in ensuring stable invasion of these Tns during transposition. Much of the diversity of prokaryotic genomes is contributed by the tightly controlled recombination activity of transposons (Tns). The Tn3 family is arguably one of the most widespread transposon families. Members carry a large range of passenger genes incorporated into their structures. Family members undergo replicative transposition using a DDE transposase to generate a cointegrate structure which is then resolved by site-specific recombination between specific DNA sequences (res) on each of the two Tn copies in the cointegrate. These sites also carry promoters controlling expression of the recombinase and transposase. We report here that a number of Tn3 members encode a type II toxin-antitoxin (TA) system, typically composed of a stable toxin and a labile antitoxin that binds the toxin and inhibits its lethal activity. This system serves to improve plasmid maintenance in a bacterial population and, until recently, was believed to be associated with bacterial persistence. At least six different TA gene pairs are associated with various Tn3 members. Our data suggest that several independent acquisition events have occurred. In contrast to most Tn3 family passenger genes, which are generally located away from the transposition module, the TA gene pairs abut the res site upstream of the resolvase genes. Although their role when part of Tn3 family transposons is unclear, this finding suggests a potential role for the embedded TA in stabilizing the associated transposon with the possibility that TA expression is coupled to expression of transposase and resolvase during the transposition process itself.
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18
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Zhang Y, Teper D, Xu J, Wang N. Stringent response regulators (p)ppGpp and DksA positively regulate virulence and host adaptation of Xanthomonas citri. MOLECULAR PLANT PATHOLOGY 2019; 20:1550-1565. [PMID: 31621195 PMCID: PMC6804348 DOI: 10.1111/mpp.12865] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The bacterial stringent response is a response to nutrition deprivation and other stress conditions. In Gram-negative bacteria, this process is mediated by the small signal molecules guanosine pentaphosphate pppGpp and guanosine tetraphosphate ppGpp (collectively referred to as (p)ppGpp), and the RNA polymerase-binding transcription factor DksA. The (p)ppGpp synthetase RelA and the bifunctional (p)ppGpp synthase/hydrolase SpoT are responsible for cellular (p)ppGpp levels. Here, we investigated the roles of DksA and (p)ppGpp in the virulence traits of Xanthomonas citri subsp. citri (Xcc), the causal agent of citrus canker. ΔdksA and (p)ppGpp-deficient ΔspoTΔrelA strains caused reduced virulence and compromised growth in host plants, indicating that DksA and (p)ppGpp are required for full virulence of Xcc. To characterize the effect of stringent response regulators on gene expression, RNA-seq was conducted using ΔdksA and ΔspoTΔrelA mutant strains grown in hrp-inducing XVM2 medium. Transcriptome analyses showed that DksA and (p)ppGpp repressed the expression of genes encoding tRNAs, ribosome proteins, iron acquisition and flagellum assembly, and enhanced the expression of genes for histidine metabolism, type 3 secretion system (T3SS), type 2 secretion system (T2SS) and TonB-dependent transporters. Phenotypically, the ΔdksA and ΔspoTΔrelA strains displayed altered motility, enhanced siderophore production and were unable to cause the hypersensitive response on non-host plants. In conclusion, stringent response regulators DksA and (p)ppGpp play an important role in virulence, nutrition uptake and host adaptation of Xcc.
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Affiliation(s)
- Yanan Zhang
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceInstitute of Food and Agricultural Sciences, University of FloridaLake Alfred33850 FLUnited States
| | - Doron Teper
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceInstitute of Food and Agricultural Sciences, University of FloridaLake Alfred33850 FLUnited States
| | - Jin Xu
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceInstitute of Food and Agricultural Sciences, University of FloridaLake Alfred33850 FLUnited States
| | - Nian Wang
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceInstitute of Food and Agricultural Sciences, University of FloridaLake Alfred33850 FLUnited States
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19
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de Laia ML, Moreira LM, Gonçalves JF, Ferro MIT, Rodrigues ACP, dos Santos JN, Felestrino ÉB, Ferro JA. Gene expression analysis identifies hypothetical genes that may be critical during the infection process of Xanthomonas citri subsp. citri. ELECTRON J BIOTECHN 2019. [DOI: 10.1016/j.ejbt.2019.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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20
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Fonseca NP, Patané JSL, Varani AM, Felestrino ÉB, Caneschi WL, Sanchez AB, Cordeiro IF, Lemes CGDC, Assis RDAB, Garcia CCM, Belasque J, Martins J, Facincani AP, Ferreira RM, Jaciani FJ, de Almeida NF, Ferro JA, Moreira LM, Setubal JC. Analyses of Seven New Genomes of Xanthomonas citri pv. aurantifolii Strains, Causative Agents of Citrus Canker B and C, Show a Reduced Repertoire of Pathogenicity-Related Genes. Front Microbiol 2019; 10:2361. [PMID: 31681223 PMCID: PMC6797930 DOI: 10.3389/fmicb.2019.02361] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 09/27/2019] [Indexed: 11/21/2022] Open
Abstract
Xanthomonas citri pv. aurantifolii pathotype B (XauB) and pathotype C (XauC) are the causative agents respectively of citrus canker B and C, diseases of citrus plants related to the better-known citrus canker A, caused by Xanthomonas citri pv. citri. The study of the genomes of strains of these related bacterial species has the potential to bring new understanding to the molecular basis of citrus canker as well as their evolutionary history. Up to now only one genome sequence of XauB and only one genome sequence of XauC have been available, both in draft status. Here we present two new genome sequences of XauB (both complete) and five new genome sequences of XauC (two complete). A phylogenomic analysis of these seven genome sequences along with 24 other related Xanthomonas genomes showed that there are two distinct and well-supported major clades, the XauB and XauC clade and the Xanthomonas citri pv. citri clade. An analysis of 62 Type III Secretion System effector genes showed that there are 42 effectors with variable presence/absence or pseudogene status among the 31 genomes analyzed. A comparative analysis of secretion-system and surface-structure genes showed that the XauB and XauC genomes lack several key genes in pathogenicity-related subsystems. These subsystems, the Types I and IV Secretion Systems, and the Type IV pilus, therefore emerge as important ones in helping explain the aggressiveness of the A type of citrus canker and the apparent dominance in the field of the corresponding strain over the B and C strains.
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Affiliation(s)
- Natasha Peixoto Fonseca
- Programa de Pós-graduação em Biotecnologia, Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - José S L Patané
- Laboratório Especial de Ciclo Celular, Instituto Butantan, São Paulo, Brazil
| | - Alessandro M Varani
- Departamento de Tecnologia, Universidade Estadual Paulista, UNESP, Campus de Jaboticabal, Jaboticabal, Brazil
| | - Érica Barbosa Felestrino
- Programa de Pós-graduação em Biotecnologia, Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - Washington Luiz Caneschi
- Programa de Pós-graduação em Biotecnologia, Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - Angélica Bianchini Sanchez
- Programa de Pós-graduação em Biotecnologia, Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - Isabella Ferreira Cordeiro
- Programa de Pós-graduação em Biotecnologia, Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - Camila Gracyelle de Carvalho Lemes
- Programa de Pós-graduação em Biotecnologia, Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - Renata de Almeida Barbosa Assis
- Programa de Pós-graduação em Biotecnologia, Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - Camila Carrião Machado Garcia
- Programa de Pós-graduação em Biotecnologia, Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - José Belasque
- Departamento de Fitopatologia e Nematologia, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, Brazil
| | - Joaquim Martins
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Agda Paula Facincani
- Departamento de Tecnologia, Universidade Estadual Paulista, UNESP, Campus de Jaboticabal, Jaboticabal, Brazil
| | - Rafael Marini Ferreira
- Departamento de Tecnologia, Universidade Estadual Paulista, UNESP, Campus de Jaboticabal, Jaboticabal, Brazil
| | | | | | - Jesus Aparecido Ferro
- Departamento de Tecnologia, Universidade Estadual Paulista, UNESP, Campus de Jaboticabal, Jaboticabal, Brazil
| | - Leandro Marcio Moreira
- Programa de Pós-graduação em Biotecnologia, Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil.,Departamento de Ciências Biológicas, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - João C Setubal
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
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21
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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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22
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Santiago CRDN, Assis RDAB, Moreira LM, Digiampietri LA. Gene Tags Assessment by Comparative Genomics (GTACG): A User-Friendly Framework for Bacterial Comparative Genomics. Front Genet 2019; 10:725. [PMID: 31507629 PMCID: PMC6718126 DOI: 10.3389/fgene.2019.00725] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 07/10/2019] [Indexed: 12/04/2022] Open
Abstract
Genomics research has produced an exponential amount of data. However, the genetic knowledge pertaining to certain phenotypic characteristics is lacking. Also, a considerable part of these genomes have coding sequences (CDSs) with unknown functions, posing additional challenges to researchers. Phylogenetically close microorganisms share much of their CDSs, and certain phenotypes unique to a set of microorganisms may be the result of the genes found exclusively in those microorganisms. This study presents the GTACG framework, an easy-to-use tool for identifying in the subgroups of bacterial genomes whose microorganisms have common phenotypic characteristics, to find data that differentiates them from other associated genomes in a simple and fast way. The GTACG analysis is based on the formation of homologous CDS clusters from local alignments. The front-end is easy to use, and the installation packages have been developed to enable users lacking knowledge of programming languages or bioinformatics analyze high-throughput data using the tool. The validation of the GTACG framework has been carried out based on a case report involving a set of 161 genomes from the Xanthomonadaceae family, in which 19 families of orthologous proteins were found in 90% of the plant-associated genomes, allowing the identification of the proteins potentially associated with adaptation and virulence in plant tissue. The results show the potential use of GTACG in the search for new targets for molecular studies, and GTACG can be used as a research tool by biologists who lack advanced knowledge in the use of computational tools for bacterial comparative genomics.
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Affiliation(s)
| | - Renata de Almeida Barbosa Assis
- Biotecnology Graduate Program, Núcleo de Pesquisas em Ciências Biológicas, Federal University of Ouro Preto, Ouro Preto, Brazil
| | - Leandro Marcio Moreira
- Biotecnology Graduate Program, Núcleo de Pesquisas em Ciências Biológicas, Federal University of Ouro Preto, Ouro Preto, Brazil
- Department of Biological Sciences, Federal University of Ouro Preto, Ouro Preto, Brazil
| | - Luciano Antonio Digiampietri
- Bioinformatics Graduate Program, University of Sao Paulo, Sao Paulo, Brazil
- School of Arts, Science, and Humanities, University of Sao Paulo, Sao Paulo, Brazil
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Tan X, Qiu H, Li F, Cheng D, Zheng X, Wang B, Huang M, Li W, Li Y, Sang K, Song B, Du J, Chen H, Xie C. Complete Genome Sequence of Sequevar 14M Ralstonia solanacearum Strain HA4-1 Reveals Novel Type III Effectors Acquired Through Horizontal Gene Transfer. Front Microbiol 2019; 10:1893. [PMID: 31474968 PMCID: PMC6703095 DOI: 10.3389/fmicb.2019.01893] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/31/2019] [Indexed: 01/08/2023] Open
Abstract
Ralstonia solanacearum, which causes bacterial wilt in a broad range of plants, is considered a "species complex" due to its significant genetic diversity. Recently, we have isolated a new R. solanacearum strain HA4-1 from Hong'an county in Hubei province of China and identified it being phylotype I, sequevar 14M (phylotype I-14M). Interestingly, we found that it can cause various disease symptoms among different potato genotypes and display different pathogenic behavior compared to a phylogenetically related strain, GMI1000. To dissect the pathogenic mechanisms of HA4-1, we sequenced its whole genome by combined sequencing technologies including Illumina HiSeq2000, PacBio RS II, and BAC-end sequencing. Genome assembly results revealed the presence of a conventional chromosome, a megaplasmid as well as a 143 kb plasmid in HA4-1. Comparative genome analysis between HA4-1 and GMI1000 shows high conservation of the general virulence factors such as secretion systems, motility, exopolysaccharides (EPS), and key regulatory factors, but significant variation in the repertoire and structure of type III effectors, which could be the determinants of their differential pathogenesis in certain potato species or genotypes. We have identified two novel type III effectors that were probably acquired through horizontal gene transfer (HGT). These novel R. solanacearum effectors display homology to several YopJ and XopAC family members. We named them as RipBR and RipBS. Notably, the copy of RipBR on the plasmid is a pseudogene, while the other on the megaplasmid is normal. For RipBS, there are three copies located in the megaplasmid and plasmid, respectively. Our results have not only enriched the genome information on R. solanacearum species complex by sequencing the first sequevar 14M strain and the largest plasmid reported in R. solanacearum to date but also revealed the variation in the repertoire of type III effectors. This will greatly contribute to the future studies on the pathogenic evolution, host adaptation, and interaction between R. solanacearum and potato.
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Affiliation(s)
- Xiaodan Tan
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Huishan Qiu
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Feng Li
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Dong Cheng
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Xueao Zheng
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Bingsen Wang
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Mengshu Huang
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Wenhao Li
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Yanping Li
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Kangqi Sang
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
| | - Botao Song
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Juan Du
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Huilan Chen
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Conghua Xie
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
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24
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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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25
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Qian G, Fei S, Galperin MY. Two forms of phosphomannomutase in gammaproteobacteria: The overlooked membrane-bound form of AlgC is required for twitching motility of Lysobacter enzymogenes. Environ Microbiol 2019; 21:3969-3978. [PMID: 30938049 DOI: 10.1111/1462-2920.14615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lysobacter enzymogenes, a member of Xanthomonadaceae, is a promising tool to control crop-destroying fungal pathogens. One of its key antifungal virulence factors is the type IV pili that are required for twitching motility. Transposon mutagenesis of L. enzymogenes revealed that the production of type IV pili required the presence of the Le2152 gene, which encodes an AlgC-type phosphomannomutase/phosphoglucomutase (PMM). However, in addition to the cytoplasmic PMM domain, the Le2152 gene product contains a ~200-aa N-terminal periplasmic domain that is anchored in the membrane by two transmembrane segments and belongs to the dCache superfamily of periplasmic sensor domains. Sequence analysis identified similar membrane-anchored PMMs, encoded in conserved coaBC-dut-algC gene clusters, in a variety of gammaproteobacteria, either as the sole PMM gene in the entire genome or in addition to the gene encoding the stand-alone enzymatic domain. Previously overlooked N-terminal periplasmic sensor domains were detected in the well-characterized PMMs of Pseudomonas aeruginosa and Xanthomonas campestris, albeit not in the enzymes from Pseudomonas fluorescens, Pseudomonas putida or Azotobacter vinelandii. It appears that after the initial cloning of the enzymatically active soluble part of P. aeruginosa AlgC in 1991, all subsequent studies utilized N-terminally truncated open reading frames. The N-terminal dCache sensor domain of AlgC is predicted to modulate the PMM activity of the cytoplasmic domain in response to as yet unidentified environmental signal(s). AlgC-like membrane-bound PMMs appear to comprise yet another environmental signalling system that regulates the production of type IV pili and potentially other systems in certain gammaproteobacteria.
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Affiliation(s)
- Guoliang Qian
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China.,Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Ministry of Education, Nanjing, 210014, China
| | - Shifang Fei
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China.,Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Ministry of Education, Nanjing, 210014, China
| | - Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA
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26
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Daungfu O, Youpensuk S, Lumyong S. Endophytic Bacteria Isolated from Citrus Plants for Biological Control of Citrus Canker in Lime Plants. Trop Life Sci Res 2019; 30:73-88. [PMID: 30847034 PMCID: PMC6396886 DOI: 10.21315/tlsr2019.30.1.5] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Citrus canker caused by Xanthomonas citri subsp. citri is a disease affecting the yield and fruit quality of lime (Citrus aurantiifolia). This research investigated endophytic bacteria obtained from six healthy Citrus spp. to inhibit the pathogen and to control citrus canker on lime plants. Numbers of the endophytic bacteria isolated from C. aurantifolia, C. hystrix, C. maxima, C. nobilis, C. reticulata and C. sinensis were 28, 25, 29, 42, 12 and 34 isolates, respectively. The selected endophytic bacteria that were effective against X. citri subsp. citri were Bacillus amyloliquefaciens LE109, B. subtilis LE24 and B. tequilensis PO80. The optimum culture medium for an antagonistic effect on the pathogen in B. amyloliquefaciens LE109 and B. tequilensis PO80 was yeast extract peptone dextrose broth, and in B. subtilis LE24 was modified soluble starch broth. To control citrus canker in lime, young expanded leaves of lime plants were aseptically punctured and inoculated with 30 μl of bacterial suspension of the pathogen (108 CFU/ml in 0.85% NaCl) per punctured location. After the pathogenic inoculation for 24 h, the leaves were then inoculated with 30 μl of the selected endophytic bacteria (108 CFU/ml in 0.85% NaCl), and treated with 30 μl of the culture media containing bioactive compounds produced by the selected endophytic bacteria. The leaves inoculated with cell suspensions of B. amyloliquefaciens LE109 or B. subtilis LE24 could completely control citrus canker. However, the leaves inoculated with B. tequilensis PO80 displayed 10% disease incidence. Additionally, the leaves treated with the crude bioactive compounds of B. amyloliquefaciens LE109 or B. subtilis LE24 could completely control citrus canker. Notably, the leaves treated with the crude bioactive compounds of B. tequilensis PO80 displayed 5% disease incidence. The results of this study showed that the Bacillus strains play important roles in the biocontrol of citrus canker in lime.
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Affiliation(s)
- Orawan Daungfu
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Somchit Youpensuk
- Center of Excellence in Bioresources for Agriculture, Industry and Medicine, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Saisamorn Lumyong
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
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27
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Oliveira ACP, Ferreira RM, Ferro MIT, Ferro JA, Chandler M, Varani AM. Transposons and pathogenicity in Xanthomonas: acquisition of murein lytic transglycosylases by Tn Xax1 enhances Xanthomonas citri subsp. citri 306 virulence and fitness. PeerJ 2018; 6:e6111. [PMID: 30588403 PMCID: PMC6304161 DOI: 10.7717/peerj.6111] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Accepted: 11/12/2018] [Indexed: 01/10/2023] Open
Abstract
Xanthomonas citri subsp. citri 306 (XccA) is the causal agent of type A citrus canker (CC), one of the most significant citriculture diseases. Murein lytic transglycosylases (LT), potentially involved in XccA pathogenicity, are enzymes responsible for peptidoglycan structure assembly, remodeling and degradation. They directly impact cell wall expansion during bacterial growth, septum division allowing cell separation, cell wall remodeling allowing flagellar assembly, bacterial conjugation, muropeptide recycling, and secretion system assembly, in particular the Type 3 Secretion System involved in bacterial virulence, which play a fundamental role in XccA pathogenicity. Information about the XccA LT arsenal is patchy: little is known about family diversity, their exact role or their connection to virulence in this bacterium. Among the LTs with possible involvement in virulence, two paralogue open reading frames (ORFs) (one on the chromosome and one in plasmid pXAC64) are passenger genes of the Tn3 family transposon TnXax1, known to play a significant role in the evolution and emergence of pathogenicity in Xanthomonadales and to carry a variety of virulence determinants. This study addresses LT diversity in the XccA genome and examines the role of plasmid and chromosomal TnXax1 LT passenger genes using site-directed deletion mutagenesis and functional characterization. We identified 13 XccA LTs: 12 belong to families 1A, 1B, 1C, 1D (two copies), 1F, 1G, 3A, 3B (two copies), 5A, 6A and one which is non-categorized. The non-categorized LT is exclusive to the Xanthomonas genus and related to the 3B family but contains an additional domain linked to carbohydrate metabolism. The categorized LTs are probably involved in cell wall remodeling to allow insertion of type 3, 4 and 6 secretion systems, flagellum assembly, division and recycling of cell wall and degradation and control of peptidoglycan production. The TnXax1 passenger LT genes (3B family) are not essential to XccA or for CC development but are implicated in peptidoglycan metabolism, directly impacting bacterial fitness and CC symptom enhancement in susceptible hosts (e.g., Citrus sinensis). This underlines the role of TnXax1 as a virulence and pathogenicity-propagating agent in XccA and suggests that LT acquisition by horizontal gene transfer mediated by TnXax1 may improve bacterial fitness, conferring adaptive advantages to the plant-pathogen interaction process.
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Affiliation(s)
- Amanda C P Oliveira
- School of Agricultural and Veterinarian Sciences-Agricultural and Livestock Microbiology Graduation Program, Universidade Estadual Paulista, Jaboticabal, Sao Paulo, Brazil
| | - Rafael M Ferreira
- School of Agricultural and Veterinarian Sciences, Universidade Estadual Paulista, Jaboticabal, Sao Paulo, Brazil
| | - Maria Inês T Ferro
- School of Agricultural and Veterinarian Sciences, Universidade Estadual Paulista, Jaboticabal, Sao Paulo, Brazil
| | - Jesus A Ferro
- School of Agricultural and Veterinarian Sciences, Universidade Estadual Paulista, Jaboticabal, Sao Paulo, Brazil
| | - Mick Chandler
- Department of Biochemistry, Georgetown University, WA, USA
| | - Alessandro M Varani
- School of Agricultural and Veterinarian Sciences, Universidade Estadual Paulista, Jaboticabal, Sao Paulo, Brazil
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28
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Santiago C, Pereira V, Digiampietri L. Homology Detection Using Multilayer Maximum Clustering Coefficient. J Comput Biol 2018; 25:1328-1338. [PMID: 30102565 DOI: 10.1089/cmb.2017.0266] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Homologous sequences are widely used to understand the functions of certain genes or proteins. However, there is no consensus to solve the automatic assignment of functions to protein problem and many algorithms have different ways of identifying homologous clusters in a given set of sequences. In this article, we present an algorithm to deal with specific sets, the set of coding sequences obtained from phylogenetically close genomes (of the same species, genus, or family). When modeled as a graph, these sets have their own characteristics: they form more homogeneous and denser clusters. To solve this problem, our algorithm makes use of the clustering coefficient, which maximization can lead to the expected results from the biological point of view. In addition, we also present an algorithm for the identification of sequence domains based on graph topology. We also compared our results with those of the TribeMCL tool, a well-established algorithm of the area.
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Affiliation(s)
- Caio Santiago
- 1 Bioinformatics, University of São Paulo , São Paulo, Brazil
| | - Vivian Pereira
- 2 School of Arts, Sciences and Humanities, University of São Paulo , São Paulo, Brazil
| | - Luciano Digiampietri
- 2 School of Arts, Sciences and Humanities, University of São Paulo , São Paulo, Brazil
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29
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Alkhateeb RS, Vorhölter FJ, Steffens T, Rückert C, Ortseifen V, Hublik G, Niehaus K, Pühler A. Comparative transcription profiling of two fermentation cultures of Xanthomonas campestris pv. campestris B100 sampled in the growth and in the stationary phase. Appl Microbiol Biotechnol 2018; 102:6613-6625. [DOI: 10.1007/s00253-018-9106-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 05/07/2018] [Accepted: 05/08/2018] [Indexed: 10/14/2022]
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30
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Ference CM, Gochez AM, Behlau F, Wang N, Graham JH, Jones JB. Recent advances in the understanding of Xanthomonas citri ssp. citri pathogenesis and citrus canker disease management. MOLECULAR PLANT PATHOLOGY 2018; 19:1302-1318. [PMID: 29105297 PMCID: PMC6638175 DOI: 10.1111/mpp.12638] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 10/29/2017] [Accepted: 10/31/2017] [Indexed: 05/09/2023]
Abstract
Taxonomic status: Bacteria; Phylum Proteobacteria; Class Gammaproteobacteria; Order Xanthomonadales; Family Xanthomonadaceae; Genus Xanthomonas; Species Xanthomonas citri ssp. citri (Xcc). Host range: Compatible hosts vary in their susceptibility to citrus canker (CC), with grapefruit, lime and lemon being the most susceptible, sweet orange being moderately susceptible, and kumquat and calamondin being amongst the least susceptible. Microbiological properties: Xcc is a rod-shaped (1.5-2.0 × 0.5-0.75 µm), Gram-negative, aerobic bacterium with a single polar flagellum. The bacterium forms yellow colonies on culture media as a result of the production of xanthomonadin. Distribution: Present in South America, the British Virgin Islands, Africa, the Middle East, India, Asia and the South Pacific islands. Localized incidence in the USA, Argentina, Brazil, Bolivia, Uruguay, Senegal, Mali, Burkina Faso, Tanzania, Iran, Saudi Arabia, Yemen and Bangladesh. Widespread throughout Paraguay, Comoros, China, Japan, Malaysia and Vietnam. Eradicated from South Africa, Australia and New Zealand. Absent from Europe.
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Affiliation(s)
- Christopher M. Ference
- United States Department of Agriculture, Agricultural Research Service, US Horticultural Research LaboratoryFort PierceFL 34945USA
- Department of Plant PathologyUniversity of FloridaGainesvilleFL 32611USA
| | - Alberto M. Gochez
- Citrus Pathology, EEA INTA Bella VistaBella VistaCorrientes 3432Argentina
| | - Franklin Behlau
- Department of Research & DevelopmentFundo de Defesa da Citricultura (Fundecitrus)AraraquaraSão Paulo 14.807‐040Brazil
| | - Nian Wang
- Department of Microbiology and Cell Science, Citrus Research and Education Center, University of FloridaLake AlfredFL 33850USA
| | - James H. Graham
- Department of Soil and Water Science, Citrus Research and Education Center, University of FloridaLake AlfredFL 33850USA
| | - Jeffrey B. Jones
- Department of Plant PathologyUniversity of FloridaGainesvilleFL 32611USA
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31
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Where are we going with genomics in plant pathogenic bacteria? Genomics 2018; 111:729-736. [PMID: 29678682 DOI: 10.1016/j.ygeno.2018.04.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 04/13/2018] [Indexed: 12/12/2022]
Abstract
Genome sequencing is commonly used in research laboratories right now thanks to the rise of high-throughput sequencing with higher speed and output-to-cost ratios. Here, we summarized the application of genomics in different aspects of plant bacterial pathosystems. Genomics has been used in studying the mechanisms of plant-bacteria interactions, and host specificity. It also helps with taxonomy, study of non-cultured bacteria, identification of causal agent, single cell sequencing, population genetics, and meta-transcriptomic. Overall, genomics has significantly improved our understanding of plant-microbe interaction.
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32
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Duan S, Jia H, Pang Z, Teper D, White F, Jones J, Zhou C, Wang N. Functional characterization of the citrus canker susceptibility gene CsLOB1. MOLECULAR PLANT PATHOLOGY 2018; 19:1908-1916. [PMID: 29461671 PMCID: PMC6638005 DOI: 10.1111/mpp.12667] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/29/2018] [Accepted: 02/16/2018] [Indexed: 05/08/2023]
Abstract
Xanthomonas citri ssp. citri (Xcc) is an important plant-pathogenic bacterium that causes citrus canker disease worldwide. PthA, a transcriptional activator-like (TAL) effector, directs the expression of the canker susceptibility gene CsLOB1. Here, we report our recent progress in the functional characterization of CsLOB1. Subcellular localization analysis of CsLOB1 protein in citrus protoplast revealed that CsLOB1 is primarily localized in the nucleus. We showed that CsLOB1 expression driven by dexamethasone (DEX) in CsLOB1-GR transgenic plants is associated with pustule formation following treatment with DEX. Pustule formation was not observed in DEX-treated wild-type plants and in non-treated CsLOB1-GR transgenic plants. Water soaking is typically associated with symptoms of citrus canker. Weaker water soaking was observed with pustule formation in CsLOB1-GR transgenic plants following DEX treatment. When CsLOB1-GR-transgenic Duncan grapefruit leaves were inoculated with Xcc306ΔpthA4 and treated with DEX, typical canker symptoms, including hypertrophy, hyperplasia and water soaking symptoms, were observed on DEX-treated transgenic plant leaves, but not on mock-treated plants. Twelve citrus genes that are induced by PthA4 are also stimulated by the DEX-induced expression of CsLOB1. As CsLOB1 acts as a transcriptional factor, we identified putative targets of CsLOB1 via bioinformatic and electrophoretic mobility shift assays. Cs2g20600, which encodes a zinc finger C3HC4-type RING finger protein, has been identified to be a direct target of CsLOB1. This study advances our understanding of the function of CsLOB1 and the molecular mechanism of how Xcc causes canker symptoms via CsLOB1.
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Affiliation(s)
- Shuo Duan
- Citrus Research InstituteSouthwest University, Chongqing400712, China
- Department of Microbiology and Cell Science, Citrus Research and Education Center, Institute of Food and Agricultural Sciences (IFAS)University of FloridaLake AlfredFL 33850USA
| | - Hongge Jia
- Department of Microbiology and Cell Science, Citrus Research and Education Center, Institute of Food and Agricultural Sciences (IFAS)University of FloridaLake AlfredFL 33850USA
| | - Zhiqian Pang
- Department of Microbiology and Cell Science, Citrus Research and Education Center, Institute of Food and Agricultural Sciences (IFAS)University of FloridaLake AlfredFL 33850USA
| | - Doron Teper
- Department of Microbiology and Cell Science, Citrus Research and Education Center, Institute of Food and Agricultural Sciences (IFAS)University of FloridaLake AlfredFL 33850USA
| | - Frank White
- Department of Plant PathologyUniversity of FloridaGainesvilleFL 32611USA
| | - Jeffrey Jones
- Department of Plant PathologyUniversity of FloridaGainesvilleFL 32611USA
| | - Changyong Zhou
- Citrus Research InstituteSouthwest University, Chongqing400712, China
| | - Nian Wang
- Department of Microbiology and Cell Science, Citrus Research and Education Center, Institute of Food and Agricultural Sciences (IFAS)University of FloridaLake AlfredFL 33850USA
- 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 Center, Gannan Normal UniversityGanzhouJiangxiChina
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33
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Lang JM, DuCharme E, Ibarra Caballero J, Luna E, Hartman T, Ortiz-Castro M, Korus K, Rascoe J, Jackson-Ziems TA, Broders K, Leach JE. Detection and Characterization of Xanthomonas vasicola pv. vasculorum (Cobb 1894) comb. nov. Causing Bacterial Leaf Streak of Corn in the United States. PHYTOPATHOLOGY 2017; 107:1312-1321. [PMID: 28677478 DOI: 10.1094/phyto-05-17-0168-r] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Bacterial leaf streak of corn (Zea mays) recently reached epidemic levels in three corn-growing states, and has been detected in another six states in the central United States. Xanthomonas vasicola was identified as the causal agent of this disease. A multilocus sequence alignment of six housekeeping genes and comparison of average nucleotide identity from draft genome sequence were used to confirm phylogenetic relationships and classification of this bacteria relative to other X. vasicola strains. X. vasicola isolates from Nebraska and South Africa were highly virulent on corn and sugarcane and less virulent on sorghum but caused water-soaking symptoms that are typical of X. vasicola infection on the leaves of all three hosts. Based on host range and phylogenetic comparison, we propose the taxonomic designation of this organism to X. vasicola pv. vasculorum ( Cobb 1894 ) comb. nov. Polymerase chain reaction-based diagnostic assays were developed that distinguish X. vasicola pv. vasculorum and X. vasicola pv. holcicola from each other and from other Xanthomonas spp.
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Affiliation(s)
- J M Lang
- First, second, third, fourth, sixth, tenth, and eleventh authors: Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, 80523-1177; fifth, seventh, and ninth authors: University of Nebraska-Lincoln, Lincoln 68583; seventh author: Alachua County Extension, University of Florida, Gainesville 32609; and eighth author: United States Department of Agriculture-Animal Plant Health Inspection Service-Plant Protection and Quarantine-CPHST, Beltsville, MD 20705
| | - E DuCharme
- First, second, third, fourth, sixth, tenth, and eleventh authors: Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, 80523-1177; fifth, seventh, and ninth authors: University of Nebraska-Lincoln, Lincoln 68583; seventh author: Alachua County Extension, University of Florida, Gainesville 32609; and eighth author: United States Department of Agriculture-Animal Plant Health Inspection Service-Plant Protection and Quarantine-CPHST, Beltsville, MD 20705
| | - J Ibarra Caballero
- First, second, third, fourth, sixth, tenth, and eleventh authors: Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, 80523-1177; fifth, seventh, and ninth authors: University of Nebraska-Lincoln, Lincoln 68583; seventh author: Alachua County Extension, University of Florida, Gainesville 32609; and eighth author: United States Department of Agriculture-Animal Plant Health Inspection Service-Plant Protection and Quarantine-CPHST, Beltsville, MD 20705
| | - E Luna
- First, second, third, fourth, sixth, tenth, and eleventh authors: Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, 80523-1177; fifth, seventh, and ninth authors: University of Nebraska-Lincoln, Lincoln 68583; seventh author: Alachua County Extension, University of Florida, Gainesville 32609; and eighth author: United States Department of Agriculture-Animal Plant Health Inspection Service-Plant Protection and Quarantine-CPHST, Beltsville, MD 20705
| | - T Hartman
- First, second, third, fourth, sixth, tenth, and eleventh authors: Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, 80523-1177; fifth, seventh, and ninth authors: University of Nebraska-Lincoln, Lincoln 68583; seventh author: Alachua County Extension, University of Florida, Gainesville 32609; and eighth author: United States Department of Agriculture-Animal Plant Health Inspection Service-Plant Protection and Quarantine-CPHST, Beltsville, MD 20705
| | - M Ortiz-Castro
- First, second, third, fourth, sixth, tenth, and eleventh authors: Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, 80523-1177; fifth, seventh, and ninth authors: University of Nebraska-Lincoln, Lincoln 68583; seventh author: Alachua County Extension, University of Florida, Gainesville 32609; and eighth author: United States Department of Agriculture-Animal Plant Health Inspection Service-Plant Protection and Quarantine-CPHST, Beltsville, MD 20705
| | - K Korus
- First, second, third, fourth, sixth, tenth, and eleventh authors: Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, 80523-1177; fifth, seventh, and ninth authors: University of Nebraska-Lincoln, Lincoln 68583; seventh author: Alachua County Extension, University of Florida, Gainesville 32609; and eighth author: United States Department of Agriculture-Animal Plant Health Inspection Service-Plant Protection and Quarantine-CPHST, Beltsville, MD 20705
| | - J Rascoe
- First, second, third, fourth, sixth, tenth, and eleventh authors: Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, 80523-1177; fifth, seventh, and ninth authors: University of Nebraska-Lincoln, Lincoln 68583; seventh author: Alachua County Extension, University of Florida, Gainesville 32609; and eighth author: United States Department of Agriculture-Animal Plant Health Inspection Service-Plant Protection and Quarantine-CPHST, Beltsville, MD 20705
| | - T A Jackson-Ziems
- First, second, third, fourth, sixth, tenth, and eleventh authors: Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, 80523-1177; fifth, seventh, and ninth authors: University of Nebraska-Lincoln, Lincoln 68583; seventh author: Alachua County Extension, University of Florida, Gainesville 32609; and eighth author: United States Department of Agriculture-Animal Plant Health Inspection Service-Plant Protection and Quarantine-CPHST, Beltsville, MD 20705
| | - K Broders
- First, second, third, fourth, sixth, tenth, and eleventh authors: Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, 80523-1177; fifth, seventh, and ninth authors: University of Nebraska-Lincoln, Lincoln 68583; seventh author: Alachua County Extension, University of Florida, Gainesville 32609; and eighth author: United States Department of Agriculture-Animal Plant Health Inspection Service-Plant Protection and Quarantine-CPHST, Beltsville, MD 20705
| | - J E Leach
- First, second, third, fourth, sixth, tenth, and eleventh authors: Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, 80523-1177; fifth, seventh, and ninth authors: University of Nebraska-Lincoln, Lincoln 68583; seventh author: Alachua County Extension, University of Florida, Gainesville 32609; and eighth author: United States Department of Agriculture-Animal Plant Health Inspection Service-Plant Protection and Quarantine-CPHST, Beltsville, MD 20705
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Zhang J, Huguet ‐Tapia JC, Hu Y, Jones J, Wang N, Liu S, White FF. Homologues of CsLOB1 in citrus function as disease susceptibility genes in citrus canker. MOLECULAR PLANT PATHOLOGY 2017; 18:798-810. [PMID: 27276658 PMCID: PMC6638217 DOI: 10.1111/mpp.12441] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 05/01/2016] [Accepted: 06/05/2016] [Indexed: 05/06/2023]
Abstract
The lateral organ boundary domain (LBD) genes encode a group of plant-specific proteins that function as transcription factors in the regulation of plant growth and development. Citrus sinensis lateral organ boundary 1 (CsLOB1) is a member of the LBD family and functions as a disease susceptibility gene in citrus bacterial canker (CBC). Thirty-four LBD members have been identified from the Citrus sinensis genome. We assessed the potential for additional members of LBD genes in citrus to function as surrogates for CsLOB1 in CBC, and compared host gene expression on induction of different LBD genes. Using custom-designed transcription activator-like (TAL) effectors, two members of the same clade as CsLOB1, named CsLOB2 and CsLOB3, were found to be capable of functioning similarly to CsLOB1 in CBC. RNA sequencing and quantitative reverse transcription-polymerase chain reaction analyses revealed a set of cell wall metabolic genes that are associated with CsLOB1, CsLOB2 and CsLOB3 expression and may represent downstream genes involved in CBC.
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Affiliation(s)
- Junli Zhang
- Department of Plant PathologyUniversity of FloridaGainesvilleFLUSA 32611
| | | | - Yang Hu
- Department of Plant PathologyUniversity of FloridaGainesvilleFLUSA 32611
- Present address:
Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijingChina 100101
| | - Jeffrey Jones
- Department of Plant PathologyUniversity of FloridaGainesvilleFLUSA 32611
| | - Nian Wang
- Citrus Research and Education Center/Department of Microbiology and Cell ScienceUniversity of FloridaLake AlfredFLUSA 33850
| | - Sanzhen Liu
- Department of Plant PathologyKansas State UniversityManhattanKSUSA 66506
| | - Frank F. White
- Department of Plant PathologyUniversity of FloridaGainesvilleFLUSA 32611
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Schatschneider S, Schneider J, Blom J, Létisse F, Niehaus K, Goesmann A, Vorhölter FJ. Systems and synthetic biology perspective of the versatile plant-pathogenic and polysaccharide-producing bacterium Xanthomonas campestris. Microbiology (Reading) 2017; 163:1117-1144. [DOI: 10.1099/mic.0.000473] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Sarah Schatschneider
- Abteilung für Proteom und Metabolomforschung, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Bielefeld, Germany
- Present address: Evonik Nutrition and Care GmbH, Kantstr. 2, 33790 Halle-Künsebeck, Germany
| | - Jessica Schneider
- Bioinformatics Resource Facility, Centrum für Biotechnologie, Universität Bielefeld, Germany
- Present address: Evonik Nutrition and Care GmbH, Kantstr. 2, 33790 Halle-Künsebeck, Germany
| | - Jochen Blom
- Bioinformatics and Systems Biology, Justus-Liebig-University Gießen, Germany
| | - Fabien Létisse
- LISBP, Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - Karsten Niehaus
- Abteilung für Proteom und Metabolomforschung, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Bielefeld, Germany
| | - Alexander Goesmann
- Bioinformatics and Systems Biology, Justus-Liebig-University Gießen, Germany
| | - Frank-Jörg Vorhölter
- Institut für Genomforschung und Systembiologie, Centrum für Biotechnology (CeBiTec), Universität Bielefeld, Bielefeld, Germany
- Present address: MVZ Dr. Eberhard & Partner Dortmund, Dortmund, Germany
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Complete Genome Sequences of Three Xanthomonas citri Strains from Texas. GENOME ANNOUNCEMENTS 2017; 5:5/28/e00609-17. [PMID: 28705973 PMCID: PMC5511912 DOI: 10.1128/genomea.00609-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The complete genome sequences of three Xanthomonas citri strains isolated from lime trees in Texas were found to belong to the Aw group. All carried nearly identical large plasmids with similarity to those of a citrus canker strain from India and to xanthomonads from Africa and Colombia. All three strains harbored unusual pthA homologs.
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Nozuma S, Matsuura E, Kodama D, Tashiro Y, Matsuzaki T, Kubota R, Izumo S, Takashima H. Effects of host restriction factors and the HTLV-1 subtype on susceptibility to HTLV-1-associated myelopathy/tropical spastic paraparesis. Retrovirology 2017; 14:26. [PMID: 28420387 PMCID: PMC5395872 DOI: 10.1186/s12977-017-0350-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 04/10/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Although human T-lymphotropic virus type 1 (HTLV-1) infection is a prerequisite for the development of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), specific provirus mutations in HAM/TSP have not yet been reported. In this study, we examined whether HAM/TSP patients had the disease-specific genomic variants of HTLV-1 by analyzing entire sequences of HTLV-1 proviruses in these patients, including familial cases. In addition, we investigated the genetic variants of host restriction factors conferring antiretroviral activity to determine which mutations may be related to resistance or susceptibility to HAM/TSP. RESULTS The subjects included 30 patients with familial HAM/TSP (f-HAM/TSP), 92 patients with sporadic HAM/TSP (s-HAM/TSP), and 89 asymptomatic HTLV-1 carriers (ACs). In all 211 samples, 37 samples (18%) were classified into transcontinental subtype and 174 samples (82%) were classified as Japanese subtype. Among three groups, the percentage of transcontinental subtype in f-HAM/TSP, s-HAM/TSP and ACs was 33, 23 and 7%, respectively. The frequency of transcontinental subtype was significantly higher in both f-HAM/TSP (p < 0.001) and s-HAM/TSP (p < 0.001) than in ACs. Fifty mutations in HTLV-1 sequences were significantly more frequent in HAM/TSP patients than in ACs, however, they were common only in transcontinental subtype. Among these mutations, ten common mutations causing amino acid changes in the HTLV-1 sequences were specific to the transcontinental subtype. We examined host restriction factors, and detected a rare variant in TRIM5α in HAM/TSP patients. The patients with TRIM5α 136Q showed lower proviral loads (PVLs) than those with 136R (354 vs. 654 copies/104 PBMC, p = 0.003). The patients with the 304L variant of TRIM5α had significantly higher PVLs than those with 304H (1669 vs. 595 copies/104 PBMC, p = 0.025). We could not find any HAM/TSP-specific mutations of host restriction factors. CONCLUSIONS Transcontinental subtype is susceptible to HAM/TSP, especially in familial cases. Ten common mutations causing amino acid changes in the HTLV-1 gene were specific to the transcontinental subtype. TRIM5α polymorphisms were associated with PVLs, indicating that TRIM5α could be implicated in HTLV-1 replication.
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Affiliation(s)
- Satoshi Nozuma
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan
| | - Eiji Matsuura
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan.
| | - Daisuke Kodama
- Division of Molecular Pathology, Center for Chronic Viral Diseases, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan
| | - Yuichi Tashiro
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan
| | - Toshio Matsuzaki
- Division of Molecular Pathology, Center for Chronic Viral Diseases, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan
| | - Ryuji Kubota
- Division of Molecular Pathology, Center for Chronic Viral Diseases, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan
| | - Shuji Izumo
- Division of Molecular Pathology, Center for Chronic Viral Diseases, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan
| | - Hiroshi Takashima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan
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Di Lorenzo F, Silipo A, Andersen Gersby LB, Palmigiano A, Lanzetta R, Garozzo D, Boyer C, Pruvost O, Newman MA, Molinaro A. Xanthomonas citri pv. citri Pathotypes: LPS Structure and Function as Microbe-Associated Molecular Patterns. Chembiochem 2017; 18:772-781. [PMID: 28186388 DOI: 10.1002/cbic.201600671] [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: 12/13/2016] [Indexed: 12/13/2022]
Abstract
Xanthomonas citri pv. citri is the pathogen responsible for Asiatic citrus canker, one of the most serious citrus diseases worldwide. The lipopolysaccharide (LPS) molecule has been demonstrated to be involved in X. citri pv. citri virulence. Despite enormous progress in investigations of the molecular mechanisms for bacterial pathogenicity, determination of the detailed LPS structure-activity relationship is limited, as the current knowledge is mainly based on structural determination of one X. citri pv. citri strain. As X. citri pv. citri strains are distinguished into three main pathogenicity groups, we characterized the full structure of the LPS from two pathotypes that differ in their host-range specificity. This revealed an intriguing difference in LPS O-chain structure. We also tested the LPSs and isolated lipid A moieties for their ability to act as microbe-associated molecular patterns in Arabidopsis thaliana. Both LPS/lipid As induced ROS accumulation, but no difference was observed between the two pathotypes.
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Affiliation(s)
- Flaviana Di Lorenzo
- Department of Chemical Sciences, University of Naples Federico II, via Cinthia 4, 80126, Naples, Italy
| | - Alba Silipo
- Department of Chemical Sciences, University of Naples Federico II, via Cinthia 4, 80126, Naples, Italy
| | | | - Angelo Palmigiano
- CNR-Istituto per i Polimeri, Compositi e Biomateriali IPCB, via Gaifami 18, 95126, Catania, Italy
| | - Rosa Lanzetta
- Department of Chemical Sciences, University of Naples Federico II, via Cinthia 4, 80126, Naples, Italy
| | - Domenico Garozzo
- CNR-Istituto per i Polimeri, Compositi e Biomateriali IPCB, via Gaifami 18, 95126, Catania, Italy
| | - Claudine Boyer
- CIRAD, UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), Saint Pierre, La Réunion, France
| | - Olivier Pruvost
- CIRAD, UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), Saint Pierre, La Réunion, France
| | - Mari-Anne Newman
- Department of Plant and Environmental Sciences, University of Copenhagen, 1871, Frederiksberg, Copenhagen, Denmark
| | - Antonio Molinaro
- Department of Chemical Sciences, University of Naples Federico II, via Cinthia 4, 80126, Naples, Italy
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Dalio RJD, Magalhães DM, Rodrigues CM, Arena GD, Oliveira TS, Souza-Neto RR, Picchi SC, Martins PMM, Santos PJC, Maximo HJ, Pacheco IS, De Souza AA, Machado MA. PAMPs, PRRs, effectors and R-genes associated with citrus-pathogen interactions. ANNALS OF BOTANY 2017; 119:749-774. [PMID: 28065920 PMCID: PMC5571375 DOI: 10.1093/aob/mcw238] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 07/08/2016] [Accepted: 10/22/2016] [Indexed: 05/08/2023]
Abstract
BACKGROUND Recent application of molecular-based technologies has considerably advanced our understanding of complex processes in plant-pathogen interactions and their key components such as PAMPs, PRRs, effectors and R-genes. To develop novel control strategies for disease prevention in citrus, it is essential to expand and consolidate our knowledge of the molecular interaction of citrus plants with their pathogens. SCOPE This review provides an overview of our understanding of citrus plant immunity, focusing on the molecular mechanisms involved in the interactions with viruses, bacteria, fungi, oomycetes and vectors related to the following diseases: tristeza, psorosis, citrus variegated chlorosis, citrus canker, huanglongbing, brown spot, post-bloom, anthracnose, gummosis and citrus root rot.
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Affiliation(s)
- Ronaldo J. D. Dalio
- Citrus Biotechnology Lab, Centro de Citricultura Sylvio Moreira, IAC, Cordeirópolis-SP, Brazil
| | - Diogo M. Magalhães
- Citrus Biotechnology Lab, Centro de Citricultura Sylvio Moreira, IAC, Cordeirópolis-SP, Brazil
| | - Carolina M. Rodrigues
- Citrus Biotechnology Lab, Centro de Citricultura Sylvio Moreira, IAC, Cordeirópolis-SP, Brazil
| | - Gabriella D. Arena
- Citrus Biotechnology Lab, Centro de Citricultura Sylvio Moreira, IAC, Cordeirópolis-SP, Brazil
| | - Tiago S. Oliveira
- Citrus Biotechnology Lab, Centro de Citricultura Sylvio Moreira, IAC, Cordeirópolis-SP, Brazil
| | - Reinaldo R. Souza-Neto
- Citrus Biotechnology Lab, Centro de Citricultura Sylvio Moreira, IAC, Cordeirópolis-SP, Brazil
| | - Simone C. Picchi
- Citrus Biotechnology Lab, Centro de Citricultura Sylvio Moreira, IAC, Cordeirópolis-SP, Brazil
| | - Paula M. M. Martins
- Citrus Biotechnology Lab, Centro de Citricultura Sylvio Moreira, IAC, Cordeirópolis-SP, Brazil
| | - Paulo J. C. Santos
- Citrus Biotechnology Lab, Centro de Citricultura Sylvio Moreira, IAC, Cordeirópolis-SP, Brazil
| | - Heros J. Maximo
- Citrus Biotechnology Lab, Centro de Citricultura Sylvio Moreira, IAC, Cordeirópolis-SP, Brazil
| | - Inaiara S. Pacheco
- Citrus Biotechnology Lab, Centro de Citricultura Sylvio Moreira, IAC, Cordeirópolis-SP, Brazil
| | - Alessandra A. De Souza
- Citrus Biotechnology Lab, Centro de Citricultura Sylvio Moreira, IAC, Cordeirópolis-SP, Brazil
| | - Marcos A. Machado
- Citrus Biotechnology Lab, Centro de Citricultura Sylvio Moreira, IAC, Cordeirópolis-SP, Brazil
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Hersemann L, Wibberg D, Blom J, Goesmann A, Widmer F, Vorhölter FJ, Kölliker R. Comparative genomics of host adaptive traits in Xanthomonas translucens pv. graminis. BMC Genomics 2017; 18:35. [PMID: 28056815 PMCID: PMC5217246 DOI: 10.1186/s12864-016-3422-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 12/14/2016] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Xanthomonas translucens pathovars differ in their individual host ranges among Poaceae. As the causal agent of bacterial wilt in Italian ryegrass (Lolium multiflorum Lam.), X. translucens pv. graminis (Xtg) is one of the most important bacterial pathogens in temperate grassland regions. The genomes of six Xtg strains from Switzerland, Norway, and New Zealand were sequenced in order to gain insight into conserved genomic traits from organisms covering a wide geographical range. Subsequent comparative analysis with previously published genome data of seven non-graminis X. translucens strains including the pathovars arrhenatheri, poae, phlei, cerealis, undulosa, and translucens was conducted to identify candidate genes linked to the host adaptation of Xtg to Italian ryegrass. RESULTS Phylogenetic analysis revealed a tight clustering of Xtg strains, which were found to share a large core genome. Conserved genomic traits included a non-canonical type III secretion system (T3SS) and a type IV pilus (T4P), which both revealed distinct primary structures of the pilins when compared to the non-graminis X. translucens strains. Xtg-specific traits that had no homologues in the other X. translucens strains were further found to comprise several hypothetical proteins, a TonB-dependent receptor, transporters, and effector proteins as well as toxin-antitoxin systems and DNA methyltransferases. While a nearly complete flagellar gene cluster was identified in one of the sequenced Xtg strains, phenotypic analysis pointed to swimming-deficiency as a common trait of the pathovar graminis. CONCLUSION Our study suggests that host adaptation of X. translucens pv. graminis may be conferred by a combination of pathovar-specific effector proteins, regulatory mechanisms, and adapted nutrient acquisition. Sequence deviations of pathogen-associated molecular patterns (PAMPs), as observed for the pilins of the T4P and T3SS, are moreover likely to impede perception by the plant defense machinery and thus facilitate successful host colonization of Italian ryegrass.
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Affiliation(s)
| | - Daniel Wibberg
- Center for Biotechnology, Bielefeld University, 33615, Bielefeld, Germany
| | - Jochen Blom
- Bioinformatics and Systems Biology, Justus Liebig University Giessen, 35392, Giessen, Germany
| | - Alexander Goesmann
- Bioinformatics and Systems Biology, Justus Liebig University Giessen, 35392, Giessen, Germany
| | - Franco Widmer
- Molecular Ecology, Agroscope, 8046, Zurich, Switzerland
| | - Frank-Jörg Vorhölter
- Center for Biotechnology, Bielefeld University, 33615, Bielefeld, Germany
- MVZ Dr. Eberhard & Partner Dortmund, 44137, Dortmund, Germany
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Mutka AM, Fentress SJ, Sher JW, Berry JC, Pretz C, Nusinow DA, Bart R. Quantitative, Image-Based Phenotyping Methods Provide Insight into Spatial and Temporal Dimensions of Plant Disease. PLANT PHYSIOLOGY 2016; 172:650-660. [PMID: 27443602 PMCID: PMC5047107 DOI: 10.1104/pp.16.00984] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 07/19/2016] [Indexed: 05/25/2023]
Abstract
Plant disease symptoms exhibit complex spatial and temporal patterns that are challenging to quantify. Image-based phenotyping approaches enable multidimensional characterization of host-microbe interactions and are well suited to capture spatial and temporal data that are key to understanding disease progression. We applied image-based methods to investigate cassava bacterial blight, which is caused by the pathogen Xanthomonas axonopodis pv. manihotis (Xam). We generated Xam strains in which individual predicted type III effector (T3E) genes were mutated and applied multiple imaging approaches to investigate the role of these proteins in bacterial virulence. Specifically, we quantified bacterial populations, water-soaking disease symptoms, and pathogen spread from the site of inoculation over time for strains with mutations in avrBs2, xopX, and xopK as compared to wild-type Xam ∆avrBs2 and ∆xopX both showed reduced growth in planta and delayed spread through the vasculature system of cassava. ∆avrBs2 exhibited reduced water-soaking symptoms at the site of inoculation. In contrast, ∆xopK exhibited enhanced induction of disease symptoms at the site of inoculation but reduced spread through the vasculature. Our results highlight the importance of adopting a multipronged approach to plant disease phenotyping to more fully understand the roles of T3Es in virulence. Finally, we demonstrate that the approaches used in this study can be extended to many host-microbe systems and increase the dimensions of phenotype that can be explored.
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Affiliation(s)
- Andrew M Mutka
- Donald Danforth Plant Science Center, Saint Louis, MO 63132
| | | | - Joel W Sher
- Donald Danforth Plant Science Center, Saint Louis, MO 63132
| | | | - Chelsea Pretz
- Donald Danforth Plant Science Center, Saint Louis, MO 63132
| | | | - Rebecca Bart
- Donald Danforth Plant Science Center, Saint Louis, MO 63132
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Jacques MA, Arlat M, Boulanger A, Boureau T, Carrère S, Cesbron S, Chen NWG, Cociancich S, Darrasse A, Denancé N, Fischer-Le Saux M, Gagnevin L, Koebnik R, Lauber E, Noël LD, Pieretti I, Portier P, Pruvost O, Rieux A, Robène I, Royer M, Szurek B, Verdier V, Vernière C. Using Ecology, Physiology, and Genomics to Understand Host Specificity in Xanthomonas. ANNUAL REVIEW OF PHYTOPATHOLOGY 2016; 54:163-87. [PMID: 27296145 DOI: 10.1146/annurev-phyto-080615-100147] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
How pathogens coevolve with and adapt to their hosts are critical to understanding how host jumps and/or acquisition of novel traits can lead to new disease emergences. The Xanthomonas genus includes Gram-negative plant-pathogenic bacteria that collectively infect a broad range of crops and wild plant species. However, individual Xanthomonas strains usually cause disease on only a few plant species and are highly adapted to their hosts, making them pertinent models to study host specificity. This review summarizes our current understanding of the molecular basis of host specificity in the Xanthomonas genus, with a particular focus on the ecology, physiology, and pathogenicity of the bacterium. Despite our limited understanding of the basis of host specificity, type III effectors, microbe-associated molecular patterns, lipopolysaccharides, transcriptional regulators, and chemotactic sensors emerge as key determinants for shaping host specificity.
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Affiliation(s)
- Marie-Agnès Jacques
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), F-49071 Beaucouzé, France; , , , , ,
| | - Matthieu Arlat
- INRA, UMR 441 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France; , , , ,
- CNRS, UMR 2594 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France
- Université de Toulouse, Université Paul Sabatier, F-31062 Toulouse, France
| | - Alice Boulanger
- INRA, UMR 441 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France; , , , ,
- CNRS, UMR 2594 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France
- Université de Toulouse, Université Paul Sabatier, F-31062 Toulouse, France
| | - Tristan Boureau
- Université Angers, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), F-49071 Beaucouzé, France;
| | - Sébastien Carrère
- INRA, UMR 441 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France; , , , ,
| | - Sophie Cesbron
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), F-49071 Beaucouzé, France; , , , , ,
| | - Nicolas W G Chen
- Agrocampus Ouest, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), F-49071 Beaucouzé, France;
| | - Stéphane Cociancich
- CIRAD, UMR Biologie et Génétique des Interactions Plante-Parasite (BGPI), F-34398 Montpellier, France; , , ,
| | - Armelle Darrasse
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), F-49071 Beaucouzé, France; , , , , ,
| | - Nicolas Denancé
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), F-49071 Beaucouzé, France; , , , , ,
| | - Marion Fischer-Le Saux
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), F-49071 Beaucouzé, France; , , , , ,
| | - Lionel Gagnevin
- IRD, CIRAD, University of Montpellier, Interactions Plantes Micro-organismes Environnement (IPME), F-34394 Montpellier, France; , , ,
| | - Ralf Koebnik
- IRD, CIRAD, University of Montpellier, Interactions Plantes Micro-organismes Environnement (IPME), F-34394 Montpellier, France; , , ,
| | - Emmanuelle Lauber
- INRA, UMR 441 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France; , , , ,
- CNRS, UMR 2594 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France
| | - Laurent D Noël
- INRA, UMR 441 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France; , , , ,
- CNRS, UMR 2594 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France
| | - Isabelle Pieretti
- CIRAD, UMR Biologie et Génétique des Interactions Plante-Parasite (BGPI), F-34398 Montpellier, France; , , ,
| | - Perrine Portier
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), F-49071 Beaucouzé, France; , , , , ,
| | - Olivier Pruvost
- CIRAD, UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), F-97410 Saint-Pierre, La Réunion, France; , ,
| | - Adrien Rieux
- CIRAD, UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), F-97410 Saint-Pierre, La Réunion, France; , ,
| | - Isabelle Robène
- CIRAD, UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), F-97410 Saint-Pierre, La Réunion, France; , ,
| | - Monique Royer
- CIRAD, UMR Biologie et Génétique des Interactions Plante-Parasite (BGPI), F-34398 Montpellier, France; , , ,
| | - Boris Szurek
- IRD, CIRAD, University of Montpellier, Interactions Plantes Micro-organismes Environnement (IPME), F-34394 Montpellier, France; , , ,
| | - Valérie Verdier
- IRD, CIRAD, University of Montpellier, Interactions Plantes Micro-organismes Environnement (IPME), F-34394 Montpellier, France; , , ,
| | - Christian Vernière
- CIRAD, UMR Biologie et Génétique des Interactions Plante-Parasite (BGPI), F-34398 Montpellier, France; , , ,
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Sena-Vélez M, Redondo C, Graham JH, Cubero J. Presence of Extracellular DNA during Biofilm Formation by Xanthomonas citri subsp. citri Strains with Different Host Range. PLoS One 2016; 11:e0156695. [PMID: 27248687 PMCID: PMC4889101 DOI: 10.1371/journal.pone.0156695] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 05/18/2016] [Indexed: 12/23/2022] Open
Abstract
Xanthomonas citri subsp. citri (Xcc) A strain causes citrus bacterial canker, a serious leaf, fruit and stem spotting disease of several Citrus species. X. alfalfae subsp. citrumelonis (Xac) is the cause of citrus bacterial spot, a minor disease of citrus nursery plants and X. campestris pv. campestris (Xc) is a systemic pathogen that causes black rot of cabbage. Xanthomonas spp. form biofilms in planta that facilitate the host infection process. Herein, the role of extracellular DNA (eDNA) was evaluated in the formation and stabilization of the biofilm matrix at different stages of biofilm development. Fluorescence and light microscopy, as well as DNAse treatments, were used to determine the presence of eDNA in biofilms and bacterial cultures. DNAse treatments of Xcc strains and Xac reduced biofilm formation at the initial stage of development, as well as disrupted preformed biofilm. By comparison, no significant effect of the DNAse was detected for biofilm formation by Xc. DNAse effects on biofilm formation or disruption varied among Xcc strains and Xanthomonas species which suggest different roles for eDNA. Variation in the structure of fibers containing eDNA in biofilms, bacterial cultures, and in twitching motility was also visualized by microscopy. The proposed roles for eDNA are as an adhesin in the early stages of biofilm formation, as an structural component of mature bacterial aggregates, and twitching motility structures.
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Affiliation(s)
- Marta Sena-Vélez
- Department of Plant Protection, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Cristina Redondo
- Department of Plant Protection, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - James H. Graham
- Citrus Research and Education Center (CREC), University of Florida, Lake Alfred, Florida, United States of America
| | - Jaime Cubero
- Department of Plant Protection, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
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Hu Y, Duan S, Zhang Y, Shantharaj D, Jones JB, Wang N. Temporal Transcription Profiling of Sweet Orange in Response to PthA4-Mediated Xanthomonas citri subsp. citri Infection. PHYTOPATHOLOGY 2016; 106:442-451. [PMID: 26780431 DOI: 10.1094/phyto-09-15-0201-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Citrus canker, caused by Xanthomonas citri subsp. citri, is a devastating disease of most commercial citrus varieties. In our previous study, we analyzed the transcriptional response of 'Valencia' sweet orange to X. citri subsp. citri wild-type and pthA4 mutant infection at 48 h postinoculation (hpi). Using microarray analysis, two PthA4 targets, CsLOB1 and CsSWEET1, were identified. We have shown that PthA4 binds to the effector binding element (EBE) of CsLOB1 and activates gene expression of this susceptibility gene. However, how PthA4 modulates host genes at different stages of infection remains to be determined. In this study, we compared the transcriptional profiles between citrus leaf tissue inoculated with Xcc306 and those inoculated with a pthA4-deletion mutant strain (Xcc306∆pthA4) at 6, 48, and 120 hpi. At both 48 and 120 hpi, the PthA4-mediated infection significantly upregulated expression of a variety of genes involved in cell-wall degradation and modification, DNA packaging, G-protein, protein synthesis, sucrose metabolism, and cell division functions, while the downregulated genes were mainly enriched in photosynthesis, transport, secondary metabolism, cytochrome P450, and various plant defense-associated mechanisms. To validate microarray results, gene expression of 26 genes representing genes associated with cell-wall-associated, immunity system, and carbohydrate metabolism was confirmed using quantitative reverse-transcription polymerase chain reaction. Expression patterns of these genes at 48 and 120 hpi were consistent with the microarray results. We also identified putative EBE for PthA4 (EBEPthA4) in the promoter regions of multiple genes upregulated by PthA4, to which PthA4 might bind directly to control their gene expression. Our study provided a dynamic picture of citrus genes regulated by PthA4 during the X. citri subsp. citri infection of citrus leaves at different stages. This study will be useful in further understanding the virulence mechanism of X. citri subsp. citri and identifying potential targets of PthA4.
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Affiliation(s)
- Yang Hu
- First, fourth, and fifth authors: Department of Plant Pathology, University of Florida, Gainesville 32611; and second, third, and sixth authors: Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, 700 Experiment Station Road, Lake Alfred 33850
| | - Shuo Duan
- First, fourth, and fifth authors: Department of Plant Pathology, University of Florida, Gainesville 32611; and second, third, and sixth authors: Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, 700 Experiment Station Road, Lake Alfred 33850
| | - Yunzeng Zhang
- First, fourth, and fifth authors: Department of Plant Pathology, University of Florida, Gainesville 32611; and second, third, and sixth authors: Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, 700 Experiment Station Road, Lake Alfred 33850
| | - Deepak Shantharaj
- First, fourth, and fifth authors: Department of Plant Pathology, University of Florida, Gainesville 32611; and second, third, and sixth authors: Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, 700 Experiment Station Road, Lake Alfred 33850
| | - Jeffrey B Jones
- First, fourth, and fifth authors: Department of Plant Pathology, University of Florida, Gainesville 32611; and second, third, and sixth authors: Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, 700 Experiment Station Road, Lake Alfred 33850
| | - Nian Wang
- First, fourth, and fifth authors: Department of Plant Pathology, University of Florida, Gainesville 32611; and second, third, and sixth authors: Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, 700 Experiment Station Road, Lake Alfred 33850
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Alkhateeb RS, Vorhölter FJ, Rückert C, Mentz A, Wibberg D, Hublik G, Niehaus K, Pühler A. Genome wide transcription start sites analysis of Xanthomonas campestris pv. campestris B100 with insights into the gum gene cluster directing the biosynthesis of the exopolysaccharide xanthan. J Biotechnol 2016; 225:18-28. [PMID: 26975844 DOI: 10.1016/j.jbiotec.2016.03.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 03/08/2016] [Accepted: 03/10/2016] [Indexed: 01/18/2023]
Abstract
Xanthomonas campestris pv. campestris (Xcc) is the major producer of the exopolysaccharide xanthan, the commercially most important natural polysaccharide of microbial origin. The current work provides deeper insights into the yet uncharacterized transcriptomic features of the xanthan producing strain Xcc-B100. Towards this goal, RNA sequencing of a library based on the selective enrichment of the 5' ends of native transcripts was performed. This approach resulted in the genome wide identification of 3067 transcription start sites (TSSs) that were further classified based on their genomic positions. Among them, 1545 mapped upstream of an actively transcribed CDS and 1363 were classified as novel TSSs representing antisense, internal, and TSSs belonging to previously unidentified genomic features. Analyzing the transcriptional strength of primary and antisense TSSs revealed that in some instances antisense transcription seemed to be initiated at a higher level than its sense counterpart. Mapping the exact positions of TSSs aided in the identification of promoter consensus motifs, ribosomal binding sites, and enhanced the genome annotation of 159 in silico predicted translational start (TLS) sites. The global view on length distribution of the 5' untranslated regions (5'-UTRs) deduced from the data pointed to the occurrence of leaderless transcripts and transcripts with unusually long 5'-UTRs, in addition to identifying seven putative riboswitch elements for Xcc-B100. Concerning the biosynthesis of xanthan, we focused on the transcriptional organization of the gum gene cluster. Under the conditions tested, we present evidence for a complex transcription pattern of the gum genes with multiple TSSs and an obvious considerable role of antisense transcription. The gene gumB, encoding an outer membrane xanthan exporter, is presented here as an example for genes that possessed a strong antisense TSS.
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Affiliation(s)
- Rabeaa S Alkhateeb
- Abteilung für Proteom und Metabolomforschung, Fakultät für Biologie, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Universitätsstraße 27, 33615 Bielefeld, Germany
| | - Frank-Jörg Vorhölter
- Abteilung für Proteom und Metabolomforschung, Fakultät für Biologie, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Universitätsstraße 27, 33615 Bielefeld, Germany; Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Universitätsstraße 27, 33615 Bielefeld, Germany
| | - Christian Rückert
- Technologie Platform Genomics, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Universitätsstraße 27, 33615 Bielefeld, Germany
| | - Almut Mentz
- Technologie Platform Genomics, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Universitätsstraße 27, 33615 Bielefeld, Germany
| | - Daniel Wibberg
- Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Universitätsstraße 27, 33615 Bielefeld, Germany
| | - Gerd Hublik
- Jungbunzlauer Austria AG, Pernhofen 1, 2064 Wulzeshofen, Austria
| | - Karsten Niehaus
- Abteilung für Proteom und Metabolomforschung, Fakultät für Biologie, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Universitätsstraße 27, 33615 Bielefeld, Germany.
| | - Alfred Pühler
- Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Universitätsstraße 27, 33615 Bielefeld, Germany
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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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Rehm C, Wurmthaler LA, Li Y, Frickey T, Hartig JS. Investigation of a Quadruplex-Forming Repeat Sequence Highly Enriched in Xanthomonas and Nostoc sp. PLoS One 2015; 10:e0144275. [PMID: 26695179 PMCID: PMC4692102 DOI: 10.1371/journal.pone.0144275] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 11/16/2015] [Indexed: 12/04/2022] Open
Abstract
In prokaryotes simple sequence repeats (SSRs) with unit sizes of 1–5
nucleotides (nt) are causative for phase and antigenic variation. Although an
increased abundance of heptameric repeats was noticed in bacteria, reports about SSRs
of 6–9 nt are rare. In particular G-rich repeat sequences with the propensity
to fold into G-quadruplex (G4) structures have received little attention. In silico
analysis of prokaryotic genomes show putative G4 forming sequences to be abundant.
This report focuses on a surprisingly enriched G-rich repeat of the type
GGGNATC in Xanthomonas and cyanobacteria
such as Nostoc. We studied in detail the genomes of
Xanthomonas campestris pv. campestris ATCC 33913
(Xcc), Xanthomonas axonopodis pv.
citri str. 306 (Xac), and Nostoc
sp. strain PCC7120 (Ana). In all three organisms repeats
are spread all over the genome with an over-representation in non-coding regions.
Extensive variation of the number of repetitive units was observed with repeat
numbers ranging from two up to 26 units. However a clear preference for four units
was detected. The strong bias for four units coincides with the requirement of four
consecutive G-tracts for G4 formation. Evidence for G4 formation of the consensus
repeat sequences was found in biophysical studies utilizing CD spectroscopy. The
G-rich repeats are preferably located between aligned open reading frames (ORFs) and
are under-represented in coding regions or between divergent ORFs. The G-rich repeats
are preferentially located within a distance of 50 bp upstream of an ORF on the
anti-sense strand or within 50 bp from the stop codon on the sense strand. Analysis
of whole transcriptome sequence data showed that the majority of repeat sequences are
transcribed. The genetic loci in the vicinity of repeat regions show increased
genomic stability. In conclusion, we introduce and characterize a special class of
highly abundant and wide-spread quadruplex-forming repeat sequences in bacteria.
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Affiliation(s)
- Charlotte Rehm
- Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Universitätsstr. 10, 78457 Konstanz, Germany
| | - Lena A Wurmthaler
- Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Universitätsstr. 10, 78457 Konstanz, Germany
| | - Yuanhao Li
- Department of Biology, University of Konstanz, Universitätsstr. 10, 78457 Konstanz, Germany
| | - Tancred Frickey
- Department of Biology, University of Konstanz, Universitätsstr. 10, 78457 Konstanz, Germany
| | - Jörg S Hartig
- Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Universitätsstr. 10, 78457 Konstanz, Germany
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Genomics and transcriptomics of Xanthomonas campestris species challenge the concept of core type III effectome. BMC Genomics 2015; 16:975. [PMID: 26581393 PMCID: PMC4652430 DOI: 10.1186/s12864-015-2190-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 11/03/2015] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND The bacterial species Xanthomonas campestris infects a wide range of Brassicaceae. Specific pathovars of this species cause black rot (pv. campestris), bacterial blight of stock (pv. incanae) or bacterial leaf spot (pv. raphani). RESULTS In this study, we extended the genomic coverage of the species by sequencing and annotating the genomes of strains from pathovar incanae (CFBP 1606R and CFBP 2527R), pathovar raphani (CFBP 5828R) and a pathovar formerly named barbareae (CFBP 5825R). While comparative analyses identified a large core ORFeome at the species level, the core type III effectome was limited to only three putative type III effectors (XopP, XopF1 and XopAL1). In Xanthomonas, these effector proteins are injected inside the plant cells by the type III secretion system and contribute collectively to virulence. A deep and strand-specific RNA sequencing strategy was adopted in order to experimentally refine genome annotation for strain CFBP 5828R. This approach also allowed the experimental definition of novel ORFs and non-coding RNA transcripts. Using a constitutively active allele of hrpG, a master regulator of the type III secretion system, a HrpG-dependent regulon of 141 genes co-regulated with the type III secretion system was identified. Importantly, all these genes but seven are positively regulated by HrpG and 56 of those encode components of the Hrp type III secretion system and putative effector proteins. CONCLUSIONS This dataset is an important resource to mine for novel type III effector proteins as well as for bacterial genes which could contribute to pathogenicity of X. campestris.
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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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A TALE of transposition: Tn3-like transposons play a major role in the spread of pathogenicity determinants of Xanthomonas citri and other xanthomonads. mBio 2015; 6:e02505-14. [PMID: 25691597 PMCID: PMC4337579 DOI: 10.1128/mbio.02505-14] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Members of the genus Xanthomonas are among the most important phytopathogens. A key feature of Xanthomonas pathogenesis is the translocation of type III secretion system (T3SS) effector proteins (T3SEs) into the plant target cells via a T3SS. Several T3SEs and a murein lytic transglycosylase gene (mlt, required for citrus canker symptoms) are found associated with three transposition-related genes in Xanthomonas citri plasmid pXAC64. These are flanked by short inverted repeats (IRs). The region was identified as a transposon, TnXax1, with typical Tn3 family features, including a transposase and two recombination genes. Two 14-bp palindromic sequences within a 193-bp potential resolution site occur between the recombination genes. Additional derivatives carrying different T3SEs and other passenger genes occur in different Xanthomonas species. The T3SEs include transcription activator-like effectors (TALEs). Certain TALEs are flanked by the same IRs as found in TnXax1 to form mobile insertion cassettes (MICs), suggesting that they may be transmitted horizontally. A significant number of MICs carrying other passenger genes (including a number of TALE genes) were also identified, flanked by the same TnXax1 IRs and delimited by 5-bp target site duplications. We conclude that a large fraction of T3SEs, including individual TALEs and potential pathogenicity determinants, have spread by transposition and that TnXax1, which exhibits all of the essential characteristics of a functional transposon, may be involved in driving MIC transposition. We also propose that TALE genes may diversify by fork slippage during the replicative Tn3 family transposition. These mechanisms may play a crucial role in the emergence of Xanthomonas pathogenicity. Xanthomonas genomes carry many insertion sequences (IS) and transposons, which play an important role in their evolution and architecture. This study reveals a key relationship between transposons and pathogenicity determinants in Xanthomonas. We propose that several transposition events mediated by a Tn3-like element carrying different sets of passenger genes, such as different type III secretion system effectors (including transcription activation-like effectors [TALEs]), were determinant in the evolution and emergence of Xanthomonas pathogenicity. TALE genes are DNA-binding effectors that modulate plant transcription. We also present a model for generating TALE gene diversity based on fork slippage associated with the replicative transposition mechanism of Tn3-like transposons. This may provide a mechanism for niche adaptation, specialization, host-switching, and other lifestyle changes. These results will also certainly lead to novel insights into the evolution and emergence of the various diseases caused by different Xanthomonas species and pathovars.
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