1
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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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2
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Zhao Z, Hu Y, Hu Y, White AP, Wang Y. Features and algorithms: facilitating investigation of secreted effectors in Gram-negative bacteria. Trends Microbiol 2023; 31:1162-1178. [PMID: 37349207 DOI: 10.1016/j.tim.2023.05.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/22/2023] [Accepted: 05/22/2023] [Indexed: 06/24/2023]
Abstract
Gram-negative bacteria deliver effector proteins through type III, IV, or VI secretion systems (T3SSs, T4SSs, and T6SSs) into host cells, causing infections and diseases. In general, effector proteins for each of these distinct secretion systems lack homology and are difficult to identify. Sequence analysis has disclosed many common features, helping us to understand the evolution, function, and secretion mechanisms of the effectors. In combination with various algorithms, the known common features have facilitated accurate prediction of new effectors. Ensemblers or integrated pipelines achieve a better prediction of performance, which combines multiple computational models or modules with multidimensional features. Natural language processing (NLP) models also show the merits, which could enable discovery of novel features and, in turn, facilitate more precise effector prediction, extending our knowledge about each secretion mechanism.
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Affiliation(s)
- Ziyi Zhao
- Youth Innovation Team of Medical Bioinformatics, Shenzhen University Medical School, Shenzhen 518060, China
| | - Yixue Hu
- Youth Innovation Team of Medical Bioinformatics, Shenzhen University Medical School, Shenzhen 518060, China
| | - Yueming Hu
- Department of Bioinformatics, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Aaron P White
- Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Yejun Wang
- Youth Innovation Team of Medical Bioinformatics, Shenzhen University Medical School, Shenzhen 518060, China; Department of Cell Biology and Genetics, College of Basic Medicine, Shenzhen University Medical School, Shenzhen 518060, China.
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3
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Ortmann S, Marx J, Lampe C, Handrick V, Ehnert TM, Zinecker S, Reimers M, Bonas U, Erickson JL. A conserved microtubule-binding region in Xanthomonas XopL is indispensable for induced plant cell death reactions. PLoS Pathog 2023; 19:e1011263. [PMID: 37578981 PMCID: PMC10449215 DOI: 10.1371/journal.ppat.1011263] [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: 03/06/2023] [Revised: 08/24/2023] [Accepted: 07/17/2023] [Indexed: 08/16/2023] Open
Abstract
Pathogenic Xanthomonas bacteria cause disease on more than 400 plant species. These Gram-negative bacteria utilize the type III secretion system to inject type III effector proteins (T3Es) directly into the plant cell cytosol where they can manipulate plant pathways to promote virulence. The host range of a given Xanthomonas species is limited, and T3E repertoires are specialized during interactions with specific plant species. Some effectors, however, are retained across most strains, such as Xanthomonas Outer Protein L (XopL). As an 'ancestral' effector, XopL contributes to the virulence of multiple xanthomonads, infecting diverse plant species. XopL homologs harbor a combination of a leucine-rich-repeat (LRR) domain and an XL-box which has E3 ligase activity. Despite similar domain structure there is evidence to suggest that XopL function has diverged, exemplified by the finding that XopLs expressed in plants often display bacterial species-dependent differences in their sub-cellular localization and plant cell death reactions. We found that XopL from X. euvesicatoria (XopLXe) directly associates with plant microtubules (MTs) and causes strong cell death in agroinfection assays in N. benthamiana. Localization of XopLXe homologs from three additional Xanthomonas species, of diverse infection strategy and plant host, revealed that the distantly related X. campestris pv. campestris harbors a XopL (XopLXcc) that fails to localize to MTs and to cause plant cell death. Comparative sequence analyses of MT-binding XopLs and XopLXcc identified a proline-rich-region (PRR)/α-helical region important for MT localization. Functional analyses of XopLXe truncations and amino acid exchanges within the PRR suggest that MT-localized XopL activity is required for plant cell death reactions. This study exemplifies how the study of a T3E within the context of a genus rather than a single species can shed light on how effector localization is linked to biochemical activity.
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Affiliation(s)
- Simon Ortmann
- Department of Genetics, Institute for Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
- Department of Biochemistry of Plant Interactions, Leibniz Institute for Plant Biochemistry, Halle, Germany
| | - Jolina Marx
- Department of Genetics, Institute for Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Christina Lampe
- Department of Genetics, Institute for Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Vinzenz Handrick
- Department of Biochemistry of Plant Interactions, Leibniz Institute for Plant Biochemistry, Halle, Germany
| | - Tim-Martin Ehnert
- Department of Biochemistry of Plant Interactions, Leibniz Institute for Plant Biochemistry, Halle, Germany
| | - Sarah Zinecker
- Department of Plant Physiology, Institute for Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Matthias Reimers
- Department of Plant Physiology, Institute for Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Ulla Bonas
- Department of Genetics, Institute for Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Jessica Lee Erickson
- Department of Genetics, Institute for Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
- Department of Biochemistry of Plant Interactions, Leibniz Institute for Plant Biochemistry, Halle, Germany
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4
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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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6
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Siddique F, Mingxiu Y, Xiaofeng X, Zhe N, Younis H, Lili P, Junhua Z. Comparative Genomic Analysis and Rapid Molecular Detection of Xanthomonas euvesicatoria Using Unique ATP-Dependent DNA Helicase recQ, hrpB1, and hrpB2 Genes Isolated from Physalis pubescens in China. THE PLANT PATHOLOGY JOURNAL 2023; 39:191-206. [PMID: 37019829 PMCID: PMC10102564 DOI: 10.5423/ppj.oa.08.2022.0119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 01/04/2023] [Accepted: 03/07/2023] [Indexed: 06/19/2023]
Abstract
Ground cherry (Physalis pubescens) is the most prominent species in the Solanaceae family due to its nutritional content, and prospective health advantages. It is grown all over the world, but notably in northern China. In 2019 firstly bacterial leaf spot (BLS) disease was identified on P. pubescens in China that caused by both BLS pathogens Xanthomonas euvesicatoria pv. euvesicatoria resulted in substantial monetary losses. Here, we compared whole genome sequences of X. euvesicatoria to other Xanthomonas species that caused BLS diseases for high similarities and dissimilarities in genomic sequences through average nucleotide identity (ANI) and BLAST comparison. Molecular techniques and phylogenetic trees were adopted to detect X. euvesicatoria on P. pubescens using recQ, hrpB1, and hrpB2 genes for efficient and precise identification. For rapid molecular detection of X. euvesicatoria, loop-mediated isothermal amplification, polymerase chain reaction (PCR), and real-time PCR techniques were used. Whole genome comparison results showed that the genome of X. euvesicatoria was more closely relative to X. perforans than X. vesicatoria, and X. gardneri with 98%, 84%, and 86% ANI, respectively. All infected leaves of P. pubescens found positive amplification, and negative controls did not show amplification. The findings of evolutionary history revealed that isolated strains XeC10RQ, XeH9RQ, XeA10RQ, and XeB10RQ that originated from China were closely relative and highly homologous to the X. euvesicatoria. This research provides information to researchers on genomic variation in BLS pathogens, and further molecular evolution and identification of X. euvesicatoria using the unique target recQ gene through advance molecular approaches.
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Affiliation(s)
| | | | | | | | | | | | - Zhang Junhua
- Corresponding author. Phone) +86-18646561068, FAX) +86-0451-55190447, E-mail) ,
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7
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Leibman-Markus M, Gupta R, Pizarro L, Bar M. The LeEIX Locus Determines Pathogen Resistance in Tomato. PHYTOPATHOLOGY 2023; 113:277-285. [PMID: 36044638 DOI: 10.1094/phyto-01-22-0035-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The mechanisms underlying the ability of plants to differentiate between pathogens and commensals in their environment are currently unresolved. It has been suggested that spatiotemporal regulation of pattern-recognition receptor (PRR) content could be one of the components providing plants with the ability to distinguish between pathogens and nonpathogenic microbes. The LeEIX PRRs recognize xylanases derived from beneficial or commensal plant colonizers of Trichoderma species, including the xylanase known as EIX. Here, we investigated possible general roles of PRRs from the LeEIX locus in immunity and pathogen resistance in tomato. Mutating the inhibitory PRR LeEIX1, or overexpressing the activating PRR LeEIX2, resulted in resistance to a wide range of pathogens and increased basal and elicited immunity. LeEIX1 knockout caused increases in the expression level of several tested PRRs, including FLS2, as well as bacterial pathogen resistance coupled with an increase in flg22-mediated immunity. The wild tomato relative Solanum pennellii contains inactive LeEIX PRR variants. S. pennellii does not respond to elicitation with the LeEIX PRR ligand EIX. Given that EIX is derived from a mostly nonpathogenic microbe, the connection of its PRRs to disease resistance has not previously been investigated directly. Here, we observed that compared with S. lycopersicum cultivar M82, S. pennellii was more sensitive to several fungal and bacterial pathogens. Our results suggest that the LeEIX locus might determine resistance to fungal necrotrophs, whereas the resistance to biotrophs is effected in combination with a gene/quantitative trait locus not within the LeEIX locus.
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Affiliation(s)
- Meirav Leibman-Markus
- Department of Plant Pathology and Weed Research, Plant Protection Institute, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| | - Rupali Gupta
- Department of Plant Pathology and Weed Research, Plant Protection Institute, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| | - Lorena Pizarro
- Department of Plant Pathology and Weed Research, Plant Protection Institute, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| | - Maya Bar
- Department of Plant Pathology and Weed Research, Plant Protection Institute, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
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8
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Prautsch J, Erickson JL, Özyürek S, Gormanns R, Franke L, Lu Y, Marx J, Niemeyer F, Parker JE, Stuttmann J, Schattat MH. Effector XopQ-induced stromule formation in Nicotiana benthamiana depends on ETI signaling components ADR1 and NRG1. PLANT PHYSIOLOGY 2023; 191:161-176. [PMID: 36259930 PMCID: PMC9806647 DOI: 10.1093/plphys/kiac481] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 09/22/2022] [Indexed: 05/28/2023]
Abstract
In Nicotiana benthamiana, the expression of the Xanthomonas effector XANTHOMONAS OUTER PROTEIN Q (XopQ) triggers RECOGNITION OF XOPQ1 (ROQ1)-dependent effector-triggered immunity (ETI) responses accompanied by the accumulation of plastids around the nucleus and the formation of stromules. Both plastid clustering and stromules were proposed to contribute to ETI-related hypersensitive cell death and thereby to plant immunity. Whether these reactions are directly connected to ETI signaling events has not been tested. Here, we utilized transient expression experiments to determine whether XopQ-triggered plastid reactions are a result of XopQ perception by the immune receptor ROQ1 or a consequence of XopQ virulence activity. We found that N. benthamiana mutants lacking ROQ1, ENHANCED DISEASE SUSCEPTIBILITY 1, or the helper NUCLEOTIDE-BINDING LEUCINE-RICH REPEAT IMMUNE RECEPTORS (NLRs) N-REQUIRED GENE 1 (NRG1) and ACTIVATED DISEASE RESISTANCE GENE 1 (ADR1), fail to elicit XopQ-dependent host cell death and stromule formation. Mutants lacking only NRG1 lost XopQ-dependent cell death but retained some stromule induction that was abolished in the nrg1_adr1 double mutant. This analysis aligns XopQ-triggered stromules with the ETI signaling cascade but not to host programmed cell death. Furthermore, data reveal that XopQ-triggered plastid clustering is not strictly linked to stromule formation during ETI. Our data suggest that stromule formation, in contrast to chloroplast perinuclear dynamics, is an integral part of the N. benthamiana ETI response and that both NRG1 and ADR1 hNLRs play a role in this ETI response.
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Affiliation(s)
- Jennifer Prautsch
- Biology, Plant Physiology, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - Jessica Lee Erickson
- Biology, Plant Genetics, Martin-Luther-University Halle-Wittenberg, Halle, Germany
- Leibniz-Institut for Plant Biochemistry, Halle, Germany
| | - Sedef Özyürek
- Biology, Plant Physiology, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - Rahel Gormanns
- Biology, Plant Physiology, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - Lars Franke
- Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - Yang Lu
- Biology, Plant Physiology, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - Jolina Marx
- Leibniz-Institut for Plant Biochemistry, Halle, Germany
| | - Frederik Niemeyer
- Biology, Plant Physiology, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - Jane E Parker
- Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Johannes Stuttmann
- Biology, Plant Genetics, Martin-Luther-University Halle-Wittenberg, Halle, Germany
- Institute for Biosafety in Plant Biotechnology, Federal Research Centre for Cultivated Plants, Julius Kühn-Institute (JKI), Quedlinburg, Germany
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9
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Wagner N, Alburquerque M, Ecker N, Dotan E, Zerah B, Pena MM, Potnis N, Pupko T. Natural language processing approach to model the secretion signal of type III effectors. FRONTIERS IN PLANT SCIENCE 2022; 13:1024405. [PMID: 36388586 PMCID: PMC9659976 DOI: 10.3389/fpls.2022.1024405] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 10/11/2022] [Indexed: 06/16/2023]
Abstract
Type III effectors are proteins injected by Gram-negative bacteria into eukaryotic hosts. In many plant and animal pathogens, these effectors manipulate host cellular processes to the benefit of the bacteria. Type III effectors are secreted by a type III secretion system that must "classify" each bacterial protein into one of two categories, either the protein should be translocated or not. It was previously shown that type III effectors have a secretion signal within their N-terminus, however, despite numerous efforts, the exact biochemical identity of this secretion signal is generally unknown. Computational characterization of the secretion signal is important for the identification of novel effectors and for better understanding the molecular translocation mechanism. In this work we developed novel machine-learning algorithms for characterizing the secretion signal in both plant and animal pathogens. Specifically, we represented each protein as a vector in high-dimensional space using Facebook's protein language model. Classification algorithms were next used to separate effectors from non-effector proteins. We subsequently curated a benchmark dataset of hundreds of effectors and thousands of non-effector proteins. We showed that on this curated dataset, our novel approach yielded substantially better classification accuracy compared to previously developed methodologies. We have also tested the hypothesis that plant and animal pathogen effectors are characterized by different secretion signals. Finally, we integrated the novel approach in Effectidor, a web-server for predicting type III effector proteins, leading to a more accurate classification of effectors from non-effectors.
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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
| | - Michael Alburquerque
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Noa Ecker
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Edo Dotan
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Ben Zerah
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Michelle Mendonca Pena
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States
| | - 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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10
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Raffeiner M, Üstün S, Guerra T, Spinti D, Fitzner M, Sonnewald S, Baldermann S, Börnke F. The Xanthomonas type-III effector XopS stabilizes CaWRKY40a to regulate defense responses and stomatal immunity in pepper (Capsicum annuum). THE PLANT CELL 2022; 34:1684-1708. [PMID: 35134217 PMCID: PMC9048924 DOI: 10.1093/plcell/koac032] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/20/2022] [Indexed: 05/26/2023]
Abstract
As a critical part of plant immunity, cells that are attacked by pathogens undergo rapid transcriptional reprogramming to minimize virulence. Many bacterial phytopathogens use type III effector (T3E) proteins to interfere with plant defense responses, including this transcriptional reprogramming. Here, we show that Xanthomonas outer protein S (XopS), a T3E of Xanthomonas campestris pv. vesicatoria (Xcv), interacts with and inhibits proteasomal degradation of WRKY40, a transcriptional regulator of defense gene expression. Virus-induced gene silencing of WRKY40 in pepper (Capsicum annuum) enhanced plant tolerance to Xcv infection, indicating that WRKY40 represses immunity. Stabilization of WRKY40 by XopS reduces the expression of its targets, which include salicylic acid-responsive genes and the jasmonic acid signaling repressor JAZ8. Xcv bacteria lacking XopS display significantly reduced virulence when surface inoculated onto susceptible pepper leaves. XopS delivery by Xcv, as well as ectopic expression of XopS in Arabidopsis thaliana or Nicotiana benthamiana, prevented stomatal closure in response to bacteria and biotic elicitors. Silencing WRKY40 in pepper or N. benthamiana abolished XopS's ability to prevent stomatal closure. This suggests that XopS interferes with both preinvasion and apoplastic defense by manipulating WRKY40 stability and downstream gene expression, eventually altering phytohormone crosstalk to promote pathogen proliferation.
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Affiliation(s)
- Margot Raffeiner
- Leibniz-Institute of Vegetable and Ornamental Crops (IGZ), Großbeeren 14979, Germany
| | | | - Tiziana Guerra
- Leibniz-Institute of Vegetable and Ornamental Crops (IGZ), Großbeeren 14979, Germany
| | - Daniela Spinti
- Leibniz-Institute of Vegetable and Ornamental Crops (IGZ), Großbeeren 14979, Germany
- Institute of Biochemistry and Biology, University of Potsdam, Potsdam 14476, Germany
| | - Maria Fitzner
- Leibniz-Institute of Vegetable and Ornamental Crops (IGZ), Großbeeren 14979, Germany
| | - Sophia Sonnewald
- Department of Biology, Division of Biochemistry, Friedrich-Alexander-Universität, Erlangen 91058, Germany
| | - Susanne Baldermann
- Leibniz-Institute of Vegetable and Ornamental Crops (IGZ), Großbeeren 14979, Germany
- Department of Food Chemistry, Institute of Nutritional Science, University of Potsdam, Nuthetal 14558, Germany
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11
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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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Amerifar S, Norouzi M, Ghandi M. A tool for feature extraction from biological sequences. Brief Bioinform 2022; 23:6563937. [PMID: 35383372 DOI: 10.1093/bib/bbac108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 03/01/2022] [Accepted: 03/03/2022] [Indexed: 11/12/2022] Open
Abstract
With the advances in sequencing technologies, a huge amount of biological data is extracted nowadays. Analyzing this amount of data is beyond the ability of human beings, creating a splendid opportunity for machine learning methods to grow. The methods, however, are practical only when the sequences are converted into feature vectors. Many tools target this task including iLearnPlus, a Python-based tool which supports a rich set of features. In this paper, we propose a holistic tool that extracts features from biological sequences (i.e. DNA, RNA and Protein). These features are the inputs to machine learning models that predict properties, structures or functions of the input sequences. Our tool not only supports all features in iLearnPlus but also 30 additional features which exist in the literature. Moreover, our tool is based on R language which makes an alternative for bioinformaticians to transform sequences into feature vectors. We have compared the conversion time of our tool with that of iLearnPlus: we transform the sequences much faster. We convert small nucleotides by a median of 2.8X faster, while we outperform iLearnPlus by a median of 6.3X for large sequences. Finally, in amino acids, our tool achieves a median speedup of 23.9X.
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Affiliation(s)
- Sare Amerifar
- Bioinformatics, Tatbiat Modares University, Jalal Al Ahmad, 14115-111, Tehran, Iran
| | - Mahammad Norouzi
- Computer Science, Technical University of Darmstadt, Hochschulstr. 1, 64293, Hesse, Germany
| | - Mahmoud Ghandi
- Bioinformatics, Monte Rosa Therapeutics, Summer Street, 02210, Boston, United States
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Recent Advancements in Tracking Bacterial Effector Protein Translocation. Microorganisms 2022; 10:microorganisms10020260. [PMID: 35208715 PMCID: PMC8876096 DOI: 10.3390/microorganisms10020260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 11/17/2022] Open
Abstract
Bacteria-host interactions are characterized by the delivery of bacterial virulence factors, i.e., effectors, into host cells where they counteract host immunity and exploit host responses allowing bacterial survival and spreading. These effectors are translocated into host cells by means of dedicated secretion systems such as the type 3 secretion system (T3SS). A comprehensive understanding of effector translocation in a spatio-temporal manner is of critical importance to gain insights into an effector’s mode of action. Various approaches have been developed to understand timing and order of effector translocation, quantities of translocated effectors and their subcellular localization upon translocation into host cells. Recently, the existing toolset has been expanded by newly developed state-of-the art methods to monitor bacterial effector translocation and dynamics. In this review, we elaborate on reported methods and discuss recent advances and shortcomings in this area of tracking bacterial effector translocation.
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14
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Abstract
Various Gram-negative bacteria use secretion systems to secrete effector proteins that manipulate host biochemical pathways to their benefit. We and others have previously developed machine-learning algorithms to predict novel effectors. Specifically, given a set of known effectors and a set of known non-effectors, the machine-learning algorithm extracts features that distinguish these two protein groups. In the training phase, the machine learning learns how to best combine the features to separate the two groups. The trained machine learning is then applied to open reading frames (ORFs) with unknown functions, resulting in a score for each ORF, which is its likelihood to be an effector. We developed Effectidor, a web server for predicting type III effectors. In this book chapter, we provide a step-by-step introduction to the application of Effectidor, from selecting input data to analyzing the obtained predictions.
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Affiliation(s)
- Naama Wagner
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Tel Aviv, Israel
| | - Doron Teper
- Department of Plant Pathology and Weed Research, Institute of Plant Protection, Agricultural Research Organization (ARO), Volcani Center, Rishon LeZion, Israel
| | - Tal Pupko
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Tel Aviv, Israel.
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15
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Osdaghi E, Jones JB, Sharma A, Goss EM, Abrahamian P, Newberry EA, Potnis N, Carvalho R, Choudhary M, Paret ML, Timilsina S, Vallad GE. A centenary for bacterial spot of tomato and pepper. MOLECULAR PLANT PATHOLOGY 2021; 22:1500-1519. [PMID: 34472193 PMCID: PMC8578828 DOI: 10.1111/mpp.13125] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 08/03/2021] [Accepted: 08/05/2021] [Indexed: 05/08/2023]
Abstract
DISEASE SYMPTOMS Symptoms include water-soaked areas surrounded by chlorosis turning into necrotic spots on all aerial parts of plants. On tomato fruits, small, water-soaked, or slightly raised pale-green spots with greenish-white halos are formed, ultimately becoming dark brown and slightly sunken with a scabby or wart-like surface. HOST RANGE Main and economically important hosts include different types of tomatoes and peppers. Alternative solanaceous and nonsolanaceous hosts include Datura spp., Hyoscyamus spp., Lycium spp., Nicotiana rustica, Physalis spp., Solanum spp., Amaranthus lividus, Emilia fosbergii, Euphorbia heterophylla, Nicandra physaloides, Physalis pubescens, Sida glomerata, and Solanum americanum. TAXONOMIC STATUS OF THE PATHOGEN Domain, Bacteria; phylum, Proteobacteria; class, Gammaproteobacteria; order, Xanthomonadales; family, Xanthomonadaceae; genus, Xanthomonas; species, X. euvesicatoria, X. hortorum, X. vesicatoria. SYNONYMS (NONPREFERRED SCIENTIFIC NAMES) Bacterium exitiosum, Bacterium vesicatorium, Phytomonas exitiosa, Phytomonas vesicatoria, Pseudomonas exitiosa, Pseudomonas gardneri, Pseudomonas vesicatoria, Xanthomonas axonopodis pv. vesicatoria, Xanthomonas campestris pv. vesicatoria, Xanthomonas cynarae pv. gardneri, Xanthomonas gardneri, Xanthomonas perforans. MICROBIOLOGICAL PROPERTIES Colonies are gram-negative, oxidase-negative, and catalase-positive and have oxidative metabolism. Pale-yellow domed circular colonies of 1-2 mm in diameter grow on general culture media. DISTRIBUTION The bacteria are widespread in Africa, Brazil, Canada and the USA, Australia, eastern Europe, and south-east Asia. Occurrence in western Europe is restricted. PHYTOSANITARY CATEGORIZATION A2 no. 157, EU Annex designation II/A2. EPPO CODES XANTEU, XANTGA, XANTPF, XANTVE.
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Affiliation(s)
- Ebrahim Osdaghi
- Department of Plant ProtectionCollege of AgricultureUniversity of TehranKarajIran
| | - Jeffrey B. Jones
- Plant Pathology DepartmentUniversity of FloridaGainesvilleFloridaUSA
| | - Anuj Sharma
- Plant Pathology DepartmentUniversity of FloridaGainesvilleFloridaUSA
| | - Erica M. Goss
- Plant Pathology DepartmentUniversity of FloridaGainesvilleFloridaUSA
- Emerging Pathogens InstituteUniversity of FloridaGainesvilleFloridaUSA
| | - Peter Abrahamian
- Plant Pathology DepartmentUniversity of FloridaGainesvilleFloridaUSA
- Gulf Coast Research and Education CenterUniversity of FloridaWimaumaFloridaUSA
| | - Eric A. Newberry
- Department of Entomology and Plant PathologyAuburn UniversityAuburnAlabamaUSA
| | - Neha Potnis
- Department of Entomology and Plant PathologyAuburn UniversityAuburnAlabamaUSA
| | - Renato Carvalho
- Plant Pathology DepartmentUniversity of FloridaGainesvilleFloridaUSA
| | - Manoj Choudhary
- Plant Pathology DepartmentUniversity of FloridaGainesvilleFloridaUSA
| | - Mathews L. Paret
- Department of Plant PathologyNorth Florida Research and Education CenterUniversity of FloridaQuincyFloridaUSA
| | - Sujan Timilsina
- Plant Pathology DepartmentUniversity of FloridaGainesvilleFloridaUSA
| | - Gary E. Vallad
- Gulf Coast Research and Education CenterUniversity of FloridaWimaumaFloridaUSA
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16
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Type III secretion system effector subnetworks elicit distinct host immune responses to infection. Curr Opin Microbiol 2021; 64:19-26. [PMID: 34537517 DOI: 10.1016/j.mib.2021.08.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/26/2021] [Accepted: 08/27/2021] [Indexed: 01/18/2023]
Abstract
Citrobacter rodentium, a natural mouse pathogen which colonises the colon of immuno-competent mice, provides a robust model for interrogating host-pathogen-microbiota interactions in vivo. This model has been key to providing new insights into local host responses to enteric infection, including changes in intestinal epithelial cell immunometabolism and mucosal immunity. C. rodentium injects 31 bacterial effectors into epithelial cells via a type III secretion system (T3SS). Recently, these effectors were shown to be able to form multiple intracellular subnetworks which can withstand significant contractions whilst maintaining virulence. Here we highlight recent advances in understanding gut mucosal responses to infection and effector biology, as well as potential uses for artificial intelligence (AI) in understanding infectious disease and speculate on the role of T3SS effector networks in host adaption.
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Schachterle JK, Huang Q. Implication of the Type III Effector RipS1 in the Cool-Virulence of Ralstonia solanacearum Strain UW551. FRONTIERS IN PLANT SCIENCE 2021; 12:705717. [PMID: 34367225 PMCID: PMC8339923 DOI: 10.3389/fpls.2021.705717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
Members of the Ralstonia solanacearum species complex cause a variety of wilting diseases across a wide range of hosts by colonizing and blocking xylem vessels. Of great concern are race 3 biovar 2 strains of R. solanacearum capable of causing brown rot of potato at cool temperatures, which are select agents in the United States. To gain a better understanding of cool-virulence mechanisms, we generated libraries of transposon mutants in the cool-virulent R. solanacearum strain UW551 and screened 10,000 mutants using our seedling assay for significantly reduced virulence at 20°C. We found several mutants that exhibited reduced virulence at 28 and 20°C and also mutants that were only affected at the cooler temperature. One mutant of the latter chosen for further study had the transposon inserted in an intergenic region between a type III secretion system effector gene ripS1 and a major facilitator superfamily (MFS) protein gene. Gene expression analysis showed that expression of ripS1 was altered by the transposon insertion, but not the MFS protein gene. An independent mutant with this insertion upstream of ripS1 was generated and used to confirm virulence and gene expression phenotypes. The effector, RipS1, has unknown function and is part of a family of effectors belonging to the largest known type III effectors. The functional connection between RipS1 and cool-virulence of R. solanacearum UW551 suggests that RipS1 (and/or its upstream promoter element) may serve as a potential target for development of cool-virulence-specific diagnostic tools to differentiate the highly regulated cool-virulent strains from non-cool-virulent strains of R. solanacearum. Our results provide important information for continued work toward a better understanding of cool-virulence of R. solanacearum and development of proper control strategies to combat this important plant pathogen.
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Affiliation(s)
| | - Qi Huang
- Floral and Nursery Plants Research Unit, United States National Arboretum, Agricultural Research Service, United States Department of Agriculture, Beltsville, MD, United States
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18
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Moreno-Pérez A, Ramos C, Rodríguez-Moreno L. HrpL Regulon of Bacterial Pathogen of Woody Host Pseudomonas savastanoi pv. savastanoi NCPPB 3335. Microorganisms 2021; 9:microorganisms9071447. [PMID: 34361883 PMCID: PMC8303149 DOI: 10.3390/microorganisms9071447] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 06/29/2021] [Accepted: 06/29/2021] [Indexed: 11/17/2022] Open
Abstract
The Pseudomonas savastanoi species comprises a group of phytopathogenic bacteria that cause symptoms of disease in woody hosts. This is mediated by the rapid activation of a pool of virulence factors that suppress host defences and hijack the host’s metabolism to the pathogen’s benefit. The hrpL gene encodes an essential transcriptional regulator of virulence functions, including the type III secretion system (T3SS), in pathogenic bacteria. Here, we analyzed the contribution of HrpL to the virulence of four pathovars (pv.) of P. savastanoi isolated from different woody hosts (oleander, ash, broom, and dipladenia) and characterized the HrpL regulon of P. savastanoi pv. savastanoi NCPPB 3335 using two approaches: whole transcriptome sequencing (RNA-seq) and the bioinformatic prediction of candidate genes containing an hrp-box. Pathogenicity tests carried out for the P. savastanoi pvs. showed that HrpL was essential for symptom development in both non-host and host plants. The RNA-seq analysis of the HrpL regulon in P. savastanoi revealed a total of 53 deregulated genes, 49 of which were downregulated in the ΔhrpL mutant. Bioinformatic prediction resulted in the identification of 50 putative genes containing an hrp-box, 16 of which were shared with genes previously identified by RNA-seq. Although most of the genes regulated by HrpL belonged to the T3SS, we also identified some genes regulated by HrpL that could encode potential virulence factors in P. savastanoi.
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Affiliation(s)
- Alba Moreno-Pérez
- Área de Genética, Facultad de Ciencias, Campus Teatinos s/n, Universidad de Málaga, E-29010 Málaga, Spain;
- Departamento de Microbiología y Protección de Cultivos, Instituto de Hortofruticultura Subtropical y Mediterránea «La Mayora», Extensión Campus de Teatinos, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), E-29010 Málaga, Spain
| | - Cayo Ramos
- Área de Genética, Facultad de Ciencias, Campus Teatinos s/n, Universidad de Málaga, E-29010 Málaga, Spain;
- Departamento de Microbiología y Protección de Cultivos, Instituto de Hortofruticultura Subtropical y Mediterránea «La Mayora», Extensión Campus de Teatinos, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), E-29010 Málaga, Spain
- Correspondence: (C.R.); (L.R.-M.); Tel.: +34-952-132-146 (C.R.); +34-952-132-131 (L.R.-M.)
| | - Luis Rodríguez-Moreno
- Área de Genética, Facultad de Ciencias, Campus Teatinos s/n, Universidad de Málaga, E-29010 Málaga, Spain;
- Departamento de Microbiología y Protección de Cultivos, Instituto de Hortofruticultura Subtropical y Mediterránea «La Mayora», Extensión Campus de Teatinos, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), E-29010 Málaga, Spain
- Correspondence: (C.R.); (L.R.-M.); Tel.: +34-952-132-146 (C.R.); +34-952-132-131 (L.R.-M.)
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19
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Allen JP, Snitkin E, Pincus NB, Hauser AR. Forest and Trees: Exploring Bacterial Virulence with Genome-wide Association Studies and Machine Learning. Trends Microbiol 2021; 29:621-633. [PMID: 33455849 PMCID: PMC8187264 DOI: 10.1016/j.tim.2020.12.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 12/15/2022]
Abstract
The advent of inexpensive and rapid sequencing technologies has allowed bacterial whole-genome sequences to be generated at an unprecedented pace. This wealth of information has revealed an unanticipated degree of strain-to-strain genetic diversity within many bacterial species. Awareness of this genetic heterogeneity has corresponded with a greater appreciation of intraspecies variation in virulence. A number of comparative genomic strategies have been developed to link these genotypic and pathogenic differences with the aim of discovering novel virulence factors. Here, we review recent advances in comparative genomic approaches to identify bacterial virulence determinants, with a focus on genome-wide association studies and machine learning.
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Affiliation(s)
- Jonathan P Allen
- Department of Microbiology and Immunology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 60153, USA.
| | - Evan Snitkin
- Department of Microbiology and Immunology, Department of Internal Medicine/Division of Infectious Diseases, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nathan B Pincus
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Alan R Hauser
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA; Department of Medicine/Division of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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20
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Ruano-Gallego D, Sanchez-Garrido J, Kozik Z, Núñez-Berrueco E, Cepeda-Molero M, Mullineaux-Sanders C, Naemi Baghshomali Y, Slater SL, Wagner N, Glegola-Madejska I, Roumeliotis TI, Pupko T, Fernández LÁ, Rodríguez-Patón A, Choudhary JS, Frankel G. Type III secretion system effectors form robust and flexible intracellular virulence networks. Science 2021; 371:eabc9531. [PMID: 33707240 DOI: 10.1126/science.abc9531] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 12/15/2020] [Accepted: 01/15/2021] [Indexed: 12/14/2022]
Abstract
Infections with many Gram-negative pathogens, including Escherichia coli, Salmonella, Shigella, and Yersinia, rely on type III secretion system (T3SS) effectors. We hypothesized that while hijacking processes within mammalian cells, the effectors operate as a robust network that can tolerate substantial contractions. This was tested in vivo using the mouse pathogen Citrobacter rodentium (encoding 31 effectors). Sequential gene deletions showed that effector essentiality for infection was context dependent and that the network could tolerate 60% contraction while maintaining pathogenicity. Despite inducing very different colonic cytokine profiles (e.g., interleukin-22, interleukin-17, interferon-γ, or granulocyte-macrophage colony-stimulating factor), different networks induced protective immunity. Using data from >100 distinct mutant combinations, we built and trained a machine learning model able to predict colonization outcomes, which were confirmed experimentally. Furthermore, reproducing the human-restricted enteropathogenic E. coli effector repertoire in C. rodentium was not sufficient for efficient colonization, which implicates effector networks in host adaptation. These results unveil the extreme robustness of both T3SS effector networks and host responses.
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Affiliation(s)
- David Ruano-Gallego
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Julia Sanchez-Garrido
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Zuzanna Kozik
- Functional Proteomics Group, Chester Beatty Laboratories, Institute of Cancer Research, London, UK
| | - Elena Núñez-Berrueco
- Laboratorio de Inteligencia Artificial, Departamento de Inteligencia Artificial, Universidad Politécnica de Madrid, Campus de Montegancedo, Boadilla del Monte, Madrid, Spain
| | - Massiel Cepeda-Molero
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College, London, UK
| | | | - Yasaman Naemi Baghshomali
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Sabrina L Slater
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Naama Wagner
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Izabela Glegola-Madejska
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Theodoros I Roumeliotis
- Functional Proteomics Group, Chester Beatty Laboratories, Institute of Cancer Research, London, UK
| | - Tal Pupko
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Luis Ángel Fernández
- Centro Nacional de Biotecnología (CNB-CSIC), Department of Microbial Biotechnology, Madrid, Spain
| | - Alfonso Rodríguez-Patón
- Laboratorio de Inteligencia Artificial, Departamento de Inteligencia Artificial, Universidad Politécnica de Madrid, Campus de Montegancedo, Boadilla del Monte, Madrid, Spain
| | - Jyoti S Choudhary
- Functional Proteomics Group, Chester Beatty Laboratories, Institute of Cancer Research, London, UK.
| | - Gad Frankel
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College, London, UK.
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21
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Abstract
Degradation of intracellular proteins in Gram-negative bacteria regulates various cellular processes and serves as a quality control mechanism by eliminating damaged proteins. To understand what causes the proteolytic machinery of the cell to degrade some proteins while sparing others, we employed a quantitative pulsed-SILAC (stable isotope labeling with amino acids in cell culture) method followed by mass spectrometry analysis to determine the half-lives for the proteome of exponentially growing Escherichia coli, under standard conditions. We developed a likelihood-based statistical test to find actively degraded proteins and identified dozens of fast-degrading novel proteins. Finally, we used structural, physicochemical, and protein-protein interaction network descriptors to train a machine learning classifier to discriminate fast-degrading proteins from the rest of the proteome, achieving an area under the receiver operating characteristic curve (AUC) of 0.72.IMPORTANCE Bacteria use protein degradation to control proliferation, dispose of misfolded proteins, and adapt to physiological and environmental shifts, but the factors that dictate which proteins are prone to degradation are mostly unknown. In this study, we have used a combined computational-experimental approach to explore protein degradation in E. coli We discovered that the proteome of E. coli is composed of three protein populations that are distinct in terms of stability and functionality, and we show that fast-degrading proteins can be identified using a combination of various protein properties. Our findings expand the understanding of protein degradation in bacteria and have implications for protein engineering. Moreover, as rapidly degraded proteins may play an important role in pathogenesis, our findings may help to identify new potential antibacterial drug targets.
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22
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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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Oberleitner L, Poschmann G, Macorano L, Schott-Verdugo S, Gohlke H, Stühler K, Nowack ECM. The Puzzle of Metabolite Exchange and Identification of Putative Octotrico Peptide Repeat Expression Regulators in the Nascent Photosynthetic Organelles of Paulinella chromatophora. Front Microbiol 2020; 11:607182. [PMID: 33329499 PMCID: PMC7729196 DOI: 10.3389/fmicb.2020.607182] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/05/2020] [Indexed: 12/12/2022] Open
Abstract
The endosymbiotic acquisition of mitochondria and plastids more than one billion years ago was central for the evolution of eukaryotic life. However, owing to their ancient origin, these organelles provide only limited insights into the initial stages of organellogenesis. The cercozoan amoeba Paulinella chromatophora contains photosynthetic organelles-termed chromatophores-that evolved from a cyanobacterium ∼100 million years ago, independently from plastids in plants and algae. Despite the more recent origin of the chromatophore, it shows tight integration into the host cell. It imports hundreds of nucleus-encoded proteins, and diverse metabolites are continuously exchanged across the two chromatophore envelope membranes. However, the limited set of chromatophore-encoded solute transporters appears insufficient for supporting metabolic connectivity or protein import. Furthermore, chromatophore-localized biosynthetic pathways as well as multiprotein complexes include proteins of dual genetic origin, suggesting that mechanisms evolved that coordinate gene expression levels between chromatophore and nucleus. These findings imply that similar to the situation in mitochondria and plastids, also in P. chromatophora nuclear factors evolved that control metabolite exchange and gene expression in the chromatophore. Here we show by mass spectrometric analyses of enriched insoluble protein fractions that, unexpectedly, nucleus-encoded transporters are not inserted into the chromatophore inner envelope membrane. Thus, despite the apparent maintenance of its barrier function, canonical metabolite transporters are missing in this membrane. Instead we identified several expanded groups of short chromatophore-targeted orphan proteins. Members of one of these groups are characterized by a single transmembrane helix, and others contain amphipathic helices. We hypothesize that these proteins are involved in modulating membrane permeability. Thus, the mechanism generating metabolic connectivity of the chromatophore fundamentally differs from the one for mitochondria and plastids, but likely rather resembles the poorly understood mechanism in various bacterial endosymbionts in plants and insects. Furthermore, our mass spectrometric analysis revealed an expanded family of chromatophore-targeted helical repeat proteins. These proteins show similar domain architectures as known organelle-targeted expression regulators of the octotrico peptide repeat type in algae and plants. Apparently these chromatophore-targeted proteins evolved convergently to plastid-targeted expression regulators and are likely involved in gene expression control in the chromatophore.
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Affiliation(s)
- Linda Oberleitner
- Department of Biology, Institute of Microbial Cell Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Gereon Poschmann
- Medical Faculty, Institute for Molecular Medicine, Proteome Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Luis Macorano
- Department of Biology, Institute of Microbial Cell Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Stephan Schott-Verdugo
- Department of Pharmacy, Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Faculty of Engineering, Centro de Bioinformática y Simulación Molecular, Universidad de Talca, Talca, Chile
| | - Holger Gohlke
- Department of Pharmacy, Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Jülich Supercomputing Centre, John von Neumann Institute for Computing, Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Kai Stühler
- Medical Faculty, Institute for Molecular Medicine, Proteome Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Molecular Proteomics Laboratory, Biologisch-Medizinisches Forschungszentrum, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Eva C. M. Nowack
- Department of Biology, Institute of Microbial Cell Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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24
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An SQ, Potnis N, Dow M, Vorhölter FJ, He YQ, Becker A, Teper D, Li Y, Wang N, Bleris L, Tang JL. Mechanistic insights into host adaptation, virulence and epidemiology of the phytopathogen Xanthomonas. FEMS Microbiol Rev 2020; 44:1-32. [PMID: 31578554 PMCID: PMC8042644 DOI: 10.1093/femsre/fuz024] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 09/29/2019] [Indexed: 01/15/2023] Open
Abstract
Xanthomonas is a well-studied genus of bacterial plant pathogens whose members cause a variety of diseases in economically important crops worldwide. Genomic and functional studies of these phytopathogens have provided significant understanding of microbial-host interactions, bacterial virulence and host adaptation mechanisms including microbial ecology and epidemiology. In addition, several strains of Xanthomonas are important as producers of the extracellular polysaccharide, xanthan, used in the food and pharmaceutical industries. This polymer has also been implicated in several phases of the bacterial disease cycle. In this review, we summarise the current knowledge on the infection strategies and regulatory networks controlling virulence and adaptation mechanisms from Xanthomonas species and discuss the novel opportunities that this body of work has provided for disease control and plant health.
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Affiliation(s)
- Shi-Qi An
- National Biofilms Innovation Centre (NBIC), Biological Sciences, University of Southampton, University Road, Southampton SO17 1BJ, UK
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Rouse Life Science Building, Auburn University, Auburn AL36849, USA
| | - Max Dow
- School of Microbiology, Food Science & Technology Building, University College Cork, Cork T12 K8AF, Ireland
| | | | - Yong-Qiang He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning 530004, Guangxi, China
| | - Anke Becker
- Loewe Center for Synthetic Microbiology and Department of Biology, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Doron Teper
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred 33850, USA
| | - Yi Li
- Bioengineering Department, University of Texas at Dallas, 2851 Rutford Ave, Richardson, TX 75080, USA.,Center for Systems Biology, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX 75080, USA
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred 33850, USA
| | - Leonidas Bleris
- Bioengineering Department, University of Texas at Dallas, 2851 Rutford Ave, Richardson, TX 75080, USA.,Center for Systems Biology, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX 75080, USA.,Department of Biological Sciences, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX75080, USA
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning 530004, Guangxi, China
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25
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Slater SL, Frankel G. Advances and Challenges in Studying Type III Secretion Effectors of Attaching and Effacing Pathogens. Front Cell Infect Microbiol 2020; 10:337. [PMID: 32733819 PMCID: PMC7358347 DOI: 10.3389/fcimb.2020.00337] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/04/2020] [Indexed: 12/24/2022] Open
Affiliation(s)
- Sabrina L Slater
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Gad Frankel
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
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26
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Lee YW, Wang J, Newton HJ, Lithgow T. Mapping bacterial effector arsenals: in vivo and in silico approaches to defining the protein features dictating effector secretion by bacteria. Curr Opin Microbiol 2020; 57:13-21. [PMID: 32505919 DOI: 10.1016/j.mib.2020.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 04/20/2020] [Accepted: 04/26/2020] [Indexed: 12/25/2022]
Abstract
Many bacterial pathogens rely on dedicated secretion systems to translocate virulence proteins termed 'effectors' into host cells. These effectors engage and manipulate host cellular functions to support bacterial colonization and propagation. The secretion systems are molecular machines that recognize targeting 'features' in these effector proteins in vivo to selectively and efficiently secrete them. The joint analysis of whole genome sequencing data and computational predictions of amino acid characteristics of effector proteins has made available extensive lists of candidate effectors for many bacterial pathogens, among which Dot/Icm type IVB secretion system in Legionella pneumophila reigns with the largest number of effectors identified to-date. This system is also used by the causative agent of Q fever, Coxiella burnetii, to secrete a large pool of distinct effectors. By comparing these two pathogens, we provide an understanding of the rationale behind effector repertoire expansion. We will also discuss recent bioinformatic advances facilitating high-throughput discovery of secreted effectors through in silico 'feature' recognition, and the current challenge to substantiate the biological relevance and bona fide nature of effectors identified in silico.
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Affiliation(s)
- Yi Wei Lee
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, 3000 Victoria, Australia
| | - Jiawei Wang
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, 3800 Victoria, Australia
| | - Hayley J Newton
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, 3000 Victoria, Australia.
| | - Trevor Lithgow
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, 3800 Victoria, Australia.
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27
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Timilsina S, Potnis N, Newberry EA, Liyanapathiranage P, Iruegas-Bocardo F, White FF, Goss EM, Jones JB. Xanthomonas diversity, virulence and plant-pathogen interactions. Nat Rev Microbiol 2020; 18:415-427. [PMID: 32346148 DOI: 10.1038/s41579-020-0361-8] [Citation(s) in RCA: 132] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2020] [Indexed: 12/19/2022]
Abstract
Xanthomonas spp. encompass a wide range of plant pathogens that use numerous virulence factors for pathogenicity and fitness in plant hosts. In this Review, we examine recent insights into host-pathogen co-evolution, diversity in Xanthomonas populations and host specificity of Xanthomonas spp. that have substantially improved our fundamental understanding of pathogen biology. We emphasize the virulence factors in xanthomonads, such as type III secreted effectors including transcription activator-like effectors, type II secretion systems, diversity resulting in host specificity, evolution of emerging strains, activation of susceptibility genes and strategies of host evasion. We summarize the genomic diversity in several Xanthomonas spp. and implications for disease outbreaks, management strategies and breeding for disease resistance.
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Affiliation(s)
- Sujan Timilsina
- Plant Pathology Department, University of Florida, Gainesville, FL, USA
| | - Neha Potnis
- Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
| | - Eric A Newberry
- Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
| | | | | | - Frank F White
- Plant Pathology Department, University of Florida, Gainesville, FL, USA
| | - Erica M Goss
- Plant Pathology Department, University of Florida, Gainesville, FL, USA. .,Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.
| | - Jeffrey B Jones
- Plant Pathology Department, University of Florida, Gainesville, FL, USA.
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28
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Jiménez‐Guerrero I, Pérez‐Montaño F, Da Silva GM, Wagner N, Shkedy D, Zhao M, Pizarro L, Bar M, Walcott R, Sessa G, Pupko T, Burdman S. Show me your secret(ed) weapons: a multifaceted approach reveals a wide arsenal of type III-secreted effectors in the cucurbit pathogenic bacterium Acidovorax citrulli and novel effectors in the Acidovorax genus. MOLECULAR PLANT PATHOLOGY 2020; 21:17-37. [PMID: 31643123 PMCID: PMC6913199 DOI: 10.1111/mpp.12877] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The cucurbit pathogenic bacterium Acidovorax citrulli requires a functional type III secretion system (T3SS) for pathogenicity. In this bacterium, as with Xanthomonas and Ralstonia spp., an AraC-type transcriptional regulator, HrpX, regulates expression of genes encoding T3SS components and type III-secreted effectors (T3Es). The annotation of a sequenced A. citrulli strain revealed 11 T3E genes. Assuming that this could be an underestimation, we aimed to uncover the T3E arsenal of the A. citrulli model strain, M6. Thorough sequence analysis revealed 51 M6 genes whose products are similar to known T3Es. Furthermore, we combined machine learning and transcriptomics to identify novel T3Es. The machine-learning approach ranked all A. citrulli M6 genes according to their propensity to encode T3Es. RNA-Seq revealed differential gene expression between wild-type M6 and a mutant defective in HrpX: 159 and 28 genes showed significantly reduced and increased expression in the mutant relative to wild-type M6, respectively. Data combined from these approaches led to the identification of seven novel T3E candidates that were further validated using a T3SS-dependent translocation assay. These T3E genes encode hypothetical proteins that seem to be restricted to plant pathogenic Acidovorax species. Transient expression in Nicotiana benthamiana revealed that two of these T3Es localize to the cell nucleus and one interacts with the endoplasmic reticulum. This study places A. citrulli among the 'richest' bacterial pathogens in terms of T3E cargo. It also revealed novel T3Es that appear to be involved in the pathoadaptive evolution of plant pathogenic Acidovorax species.
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Affiliation(s)
- Irene Jiménez‐Guerrero
- Department of Plant Pathology and MicrobiologyThe Robert H. Smith Faculty of Agriculture, Food and EnvironmentThe Hebrew University of JerusalemRehovotIsrael
| | - Francisco Pérez‐Montaño
- Department of Plant Pathology and MicrobiologyThe Robert H. Smith Faculty of Agriculture, Food and EnvironmentThe Hebrew University of JerusalemRehovotIsrael
- Department of MicrobiologyUniversity of SevilleSevilleSpain
| | - Gustavo Mateus Da Silva
- Department of Plant Pathology and MicrobiologyThe Robert H. Smith Faculty of Agriculture, Food and EnvironmentThe Hebrew University of JerusalemRehovotIsrael
| | - Naama Wagner
- The School of Molecular Cell Biology and BiotechnologyThe George S. Wise Faculty of Life SciencesTel Aviv UniversityTel AvivIsrael
| | - Dafna Shkedy
- The School of Molecular Cell Biology and BiotechnologyThe George S. Wise Faculty of Life SciencesTel Aviv UniversityTel AvivIsrael
| | - Mei Zhao
- Department of Plant PathologyUniversity of GeorgiaAthensGAUSA
| | - Lorena Pizarro
- Department of Plant Pathology and Weed ResearchAgricultural Research OrganizationThe Volcani CenterBet DaganIsrael
| | - Maya Bar
- Department of Plant Pathology and Weed ResearchAgricultural Research OrganizationThe Volcani CenterBet DaganIsrael
| | - Ron Walcott
- Department of Plant PathologyUniversity of GeorgiaAthensGAUSA
| | - Guido Sessa
- School of Plant Sciences and Food SecurityThe George S. Wise Faculty of Life SciencesTel Aviv UniversityTel AvivIsrael
| | - Tal Pupko
- The School of Molecular Cell Biology and BiotechnologyThe George S. Wise Faculty of Life SciencesTel Aviv UniversityTel AvivIsrael
| | - Saul Burdman
- Department of Plant Pathology and MicrobiologyThe Robert H. Smith Faculty of Agriculture, Food and EnvironmentThe Hebrew University of JerusalemRehovotIsrael
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29
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Hong J, Luo Y, Mou M, Fu J, Zhang Y, Xue W, Xie T, Tao L, Lou Y, Zhu F. Convolutional neural network-based annotation of bacterial type IV secretion system effectors with enhanced accuracy and reduced false discovery. Brief Bioinform 2019; 21:1825-1836. [PMID: 31860715 DOI: 10.1093/bib/bbz120] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 08/12/2019] [Accepted: 08/21/2019] [Indexed: 12/20/2022] Open
Abstract
The type IV bacterial secretion system (SS) is reported to be one of the most ubiquitous SSs in nature and can induce serious conditions by secreting type IV SS effectors (T4SEs) into the host cells. Recent studies mainly focus on annotating new T4SE from the huge amount of sequencing data, and various computational tools are therefore developed to accelerate T4SE annotation. However, these tools are reported as heavily dependent on the selected methods and their annotation performance need to be further enhanced. Herein, a convolution neural network (CNN) technique was used to annotate T4SEs by integrating multiple protein encoding strategies. First, the annotation accuracies of nine encoding strategies integrated with CNN were assessed and compared with that of the popular T4SE annotation tools based on independent benchmark. Second, false discovery rates of various models were systematically evaluated by (1) scanning the genome of Legionella pneumophila subsp. ATCC 33152 and (2) predicting the real-world non-T4SEs validated using published experiments. Based on the above analyses, the encoding strategies, (a) position-specific scoring matrix (PSSM), (b) protein secondary structure & solvent accessibility (PSSSA) and (c) one-hot encoding scheme (Onehot), were identified as well-performing when integrated with CNN. Finally, a novel strategy that collectively considers the three well-performing models (CNN-PSSM, CNN-PSSSA and CNN-Onehot) was proposed, and a new tool (CNN-T4SE, https://idrblab.org/cnnt4se/) was constructed to facilitate T4SE annotation. All in all, this study conducted a comprehensive analysis on the performance of a collection of encoding strategies when integrated with CNN, which could facilitate the suppression of T4SS in infection and limit the spread of antimicrobial resistance.
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Affiliation(s)
- Jiajun Hong
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yongchao Luo
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Minjie Mou
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jianbo Fu
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yang Zhang
- School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
| | - Weiwei Xue
- School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
| | - Tian Xie
- Key Laboratory of Elemene Class Anti-Cancer Chinese Medicine of Zhejiang Province, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Lin Tao
- Key Laboratory of Elemene Class Anti-Cancer Chinese Medicine of Zhejiang Province, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Yan Lou
- Zhejiang Provincial Key Laboratory for Drug Clinical Research and Evaluation, The First Affiliated Hospital, Zhejiang University, Hangzhou 310000, Zhejiang, China
| | - Feng Zhu
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
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30
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Nissan G, Chalupowicz L, Sessa G, Manulis‐Sasson S, Barash I. Two Pantoea agglomerans type III effectors can transform nonpathogenic and phytopathogenic bacteria into host-specific gall-forming pathogens. MOLECULAR PLANT PATHOLOGY 2019; 20:1582-1587. [PMID: 31368647 PMCID: PMC6804341 DOI: 10.1111/mpp.12860] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Pantoea agglomerans (Pa), a widespread commensal bacterium, has evolved into a host-specific gall-forming pathogen on gypsophila and beet by acquiring a plasmid harbouring a type III secretion system (T3SS) and effectors (T3Es). Pantoea agglomerans pv. gypsophilae (Pag) elicits galls on gypsophila and a hypersensitive response on beet, whereas P. agglomerans pv. betae (Pab) elicits galls on beet and gypsophila. HsvG and HsvB are two paralogous T3Es present in both pathovars and act as host-specific transcription activators on gypsophila and beet, respectively. PthG and PseB are major T3Es that contribute to gall development of Pag and Pab, respectively. To establish the minimal combinations of T3Es that are sufficient to elicit gall symptoms, strains of the nonpathogenic bacteria Pseudomonas fluorescens 55, Pa 3-1, Pa 98 and Escherichia coli, transformed with pHIR11 harbouring a T3SS, and the phytopathogenic bacteria Erwinia amylovora, Dickeya solani and Xanthomonas campestris pv. campestris were transformed with the T3Es hsvG, hsvB, pthG and pseB, either individually or in pairs, and used to infect gypsophila and beet. Strikingly, all the tested nonpathogenic and phytopathogenic bacterial strains harbouring hsvG and pthG incited galls on gypsophila, whereas strains harbouring hsvB and pseB, with the exception of E. coli, incited galls on beet.
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Affiliation(s)
- Gal Nissan
- School of Plant Sciences and Security, Faculty of Life SciencesTel‐Aviv UniversityTel AvivIsrael
- Department of Plant Pathology and Weed ResearchARO the Volcani CenterRishon LeZion7528809Israel
| | - Laura Chalupowicz
- Department of Plant Pathology and Weed ResearchARO the Volcani CenterRishon LeZion7528809Israel
| | - Guido Sessa
- School of Plant Sciences and Security, Faculty of Life SciencesTel‐Aviv UniversityTel AvivIsrael
| | - Shulamit Manulis‐Sasson
- Department of Plant Pathology and Weed ResearchARO the Volcani CenterRishon LeZion7528809Israel
| | - Isaac Barash
- School of Plant Sciences and Security, Faculty of Life SciencesTel‐Aviv UniversityTel AvivIsrael
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Shah SMA, Haq F, Ma W, Xu X, Wang S, Xu Z, Zou L, Zhu B, Chen G. Tal1 NXtc01 in Xanthomonas translucens pv. cerealis Contributes to Virulence in Bacterial Leaf Streak of Wheat. Front Microbiol 2019; 10:2040. [PMID: 31551976 PMCID: PMC6737349 DOI: 10.3389/fmicb.2019.02040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 08/19/2019] [Indexed: 12/21/2022] Open
Abstract
Xanthomonas translucens pv. cerealis (Xtc) causes bacterial leaf streak (BLS) of important cereal crops, including wheat (Triticum aestivum) and barley (Hordeum vulgare). Transcription activator-like effectors (TALEs) play vital roles in many plant diseases caused by Xanthomonas spp., however, TALEs have not been previously characterized in Xtc. In this study, the whole genome of NXtc01, a virulent strain of Xtc from Xinjiang, China, was sequenced and compared with genomes of other Xanthomonas spp. Xtc NXtc01 consists of a single 4,622,298 bp chromosome that encodes 4,004 genes. Alignment of the NXtc01 sequence with the draft genome of Xtc strain CFBP 2541 (United States) revealed a single giant inversion and differences in the location of two tal genes, which were designated tal1 and tal2. In NXtc01, both tal genes are located on the chromosome, whereas tal2 is plasmid-encoded in CFBP 2541. The repeat variable diresidues (RVDs) at the 12th and 13th sites within Tal2 repeat units were identical in both strains, whereas Tal1 showed differences in the third RVD. Xtc NXtc01 and CFBP 2541 encoded 35 and 33 non-TALE type III effectors (T3Es), respectively. tal1, tal2, and tal-free deletion mutants of Xtc NXtc01 were constructed and evaluated for virulence. The tal1 and tal-free deletion mutants were impaired with respect to symptom development and growth in wheat, suggesting that tal1 is a virulence factor in NXtc01. This was confirmed in gain-of-function experiments that showed the introduction of tal1, but not tal2, restored virulence to the tal-free mutant. Furthermore, we generated a hrcC deletion mutant of NXtc01; the hrcC mutant was non-pathogenic on wheat and unable to elicit a hypersensitive response in the non-host Nicotiana benthamiana. Our data provide a platform for exploring the roles of both TALEs and non-TALEs in promoting BLS on wheat.
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Affiliation(s)
- Syed Mashab Ali Shah
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Fazal Haq
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Wenxiu Ma
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Xiameng Xu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Sai Wang
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Zhengyin Xu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Lifang Zou
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Bo Zhu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Gongyou Chen
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
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32
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Silva JCF, Teixeira RM, Silva FF, Brommonschenkel SH, Fontes EPB. Machine learning approaches and their current application in plant molecular biology: A systematic review. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 284:37-47. [PMID: 31084877 DOI: 10.1016/j.plantsci.2019.03.020] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/28/2019] [Accepted: 03/26/2019] [Indexed: 05/19/2023]
Abstract
Machine learning (ML) is a field of artificial intelligence that has rapidly emerged in molecular biology, thus allowing the exploitation of Big Data concepts in plant genomics. In this context, the main challenges are given in terms of how to analyze massive datasets and extract new knowledge in all levels of cellular systems research. In summary, ML techniques allow complex interactions to be inferred in several biological systems. Despite its potential, ML has been underused due to complex computational algorithms and definition terms. Therefore, a systematic review to disentangle ML approaches is relevant for plant scientists and has been considered in this study. We presented the main steps for ML development (from data selection to evaluation of classification/prediction models) with a respective discussion approaching functional genomics mainly in terms of pathogen effector genes in plant immunity. Additionally, we also considered how to access public source databases under an ML framework towards advancing plant molecular biology and introduced novel powerful tools, such as deep learning.
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Affiliation(s)
- Jose Cleydson F Silva
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Av. PH Rolfs s/n, Centro, Viçosa, MG, 36570-000, Brazil; Department of Biochemistry and Molecular Biology/Bioagro, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Ruan M Teixeira
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Av. PH Rolfs s/n, Centro, Viçosa, MG, 36570-000, Brazil; Department of Biochemistry and Molecular Biology/Bioagro, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Fabyano F Silva
- Department of Animal Science, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Sergio H Brommonschenkel
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Av. PH Rolfs s/n, Centro, Viçosa, MG, 36570-000, Brazil; Plant Pathology Department /Bioagro, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Elizabeth P B Fontes
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Av. PH Rolfs s/n, Centro, Viçosa, MG, 36570-000, Brazil; Department of Biochemistry and Molecular Biology/Bioagro, Universidade Federal de Viçosa, Viçosa, MG, Brazil.
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Dubrow Z, Sunitha S, Kim JG, Aakre CD, Girija AM, Sobol G, Teper D, Chen YC, Ozbaki-Yagan N, Vance H, Sessa G, Mudgett MB. Tomato 14-3-3 Proteins Are Required for Xv3 Disease Resistance and Interact with a Subset of Xanthomonas euvesicatoria Effectors. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:1301-1311. [PMID: 29947282 DOI: 10.1094/mpmi-02-18-0048-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The 14-3-3 phospho-binding proteins with scaffolding activity play central roles in the regulation of enzymes and signaling complexes in eukaryotes. In plants, 14-3-3 isoforms are required for disease resistance and key targets of pathogen effectors. Here, we examined the requirement of the tomato (Solanum lycopersicum) 14-3-3 isoform (TFT) protein family for Xv3 disease resistance in response to the bacterial pathogen Xanthomonas euvesicatoria. In addition, we determined whether TFT proteins interact with the repertoire of X. euvesicatoria type III secretion effector proteins, including AvrXv3, the elicitor of Xv3 resistance. We show that multiple TFT contribute to Xv3 resistance. We also show that one or more TFT proteins physically interact with multiple effectors (AvrXv3, XopE1, XopE2, XopN, XopO, XopQ, and XopAU). Genetic analyses indicate that none of the identified effectors interfere with AvrXv3-elicited resistance into Xv3 tomato leaves; however, XopE1, XopE2, and XopO are required to suppress symptom development in susceptible tomato leaves. Phospho-peptide mapping revealed that XopE2 is phosphorylated at multiple residues in planta and residues T66, T131, and S334 are required for maximal binding to TFT10. Together, our data support the hypothesis that multiple TFT proteins are involved in immune signaling during X. euvesicatoria infection.
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Affiliation(s)
- Zoe Dubrow
- 1 Department of Biology, Stanford University, Stanford, CA 94305-5020, U.S.A.; and
| | - Sukumaran Sunitha
- 2 School of Plant Sciences and Food Security, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Jung-Gun Kim
- 1 Department of Biology, Stanford University, Stanford, CA 94305-5020, U.S.A.; and
| | - Chris D Aakre
- 1 Department of Biology, Stanford University, Stanford, CA 94305-5020, U.S.A.; and
| | | | - Guy Sobol
- 2 School of Plant Sciences and Food Security, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Doron Teper
- 2 School of Plant Sciences and Food Security, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Yun Chu Chen
- 1 Department of Biology, Stanford University, Stanford, CA 94305-5020, U.S.A.; and
| | - Nejla Ozbaki-Yagan
- 1 Department of Biology, Stanford University, Stanford, CA 94305-5020, U.S.A.; and
| | - Hillary Vance
- 1 Department of Biology, Stanford University, Stanford, CA 94305-5020, U.S.A.; and
| | - Guido Sessa
- 2 School of Plant Sciences and Food Security, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Mary Beth Mudgett
- 1 Department of Biology, Stanford University, Stanford, CA 94305-5020, U.S.A.; and
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Wang J, Li J, Yang B, Xie R, Marquez-Lago TT, Leier A, Hayashida M, Akutsu T, Zhang Y, Chou KC, Selkrig J, Zhou T, Song J, Lithgow T. Bastion3: a two-layer ensemble predictor of type III secreted effectors. Bioinformatics 2018; 35:2017-2028. [PMID: 30388198 PMCID: PMC7963071 DOI: 10.1093/bioinformatics/bty914] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/15/2018] [Accepted: 10/31/2018] [Indexed: 01/31/2023] Open
Abstract
MOTIVATION Type III secreted effectors (T3SEs) can be injected into host cell cytoplasm via type III secretion systems (T3SSs) to modulate interactions between Gram-negative bacterial pathogens and their hosts. Due to their relevance in pathogen-host interactions, significant computational efforts have been put toward identification of T3SEs and these in turn have stimulated new T3SE discoveries. However, as T3SEs with new characteristics are discovered, these existing computational tools reveal important limitations: (i) most of the trained machine learning models are based on the N-terminus (or incorporating also the C-terminus) instead of the proteins' complete sequences, and (ii) the underlying models (trained with classic algorithms) employed only few features, most of which were extracted based on sequence-information alone. To achieve better T3SE prediction, we must identify more powerful, informative features and investigate how to effectively integrate these into a comprehensive model. RESULTS In this work, we present Bastion3, a two-layer ensemble predictor developed to accurately identify type III secreted effectors from protein sequence data. In contrast with existing methods that employ single models with few features, Bastion3 explores a wide range of features, from various types, trains single models based on these features and finally integrates these models through ensemble learning. We trained the models using a new gradient boosting machine, LightGBM and further boosted the models' performances through a novel genetic algorithm (GA) based two-step parameter optimization strategy. Our benchmark test demonstrates that Bastion3 achieves a much better performance compared to commonly used methods, with an ACC value of 0.959, F-value of 0.958, MCC value of 0.917 and AUC value of 0.956, which comprehensively outperformed all other toolkits by more than 5.6% in ACC value, 5.7% in F-value, 12.4% in MCC value and 5.8% in AUC value. Based on our proposed two-layer ensemble model, we further developed a user-friendly online toolkit, maximizing convenience for experimental scientists toward T3SE prediction. With its design to ease future discoveries of novel T3SEs and improved performance, Bastion3 is poised to become a widely used, state-of-the-art toolkit for T3SE prediction. AVAILABILITY AND IMPLEMENTATION http://bastion3.erc.monash.edu/. CONTACT selkrig@embl.de or wyztli@163.com or or trevor.lithgow@monash.edu. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Jiawei Wang
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, VIC, Australia
| | - Jiahui Li
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, VIC, Australia,Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Bingjiao Yang
- School of Computer Science and Information Security, Guilin University of Electronic Technology, Guilin, China
| | - Ruopeng Xie
- School of Computer Science and Information Security, Guilin University of Electronic Technology, Guilin, China
| | - Tatiana T Marquez-Lago
- Department of Genetics, School of Medicine, University of Alabama at Birmingham, AL, USA,Department of Cell, Developmental and Integrative Biology, School of Medicine, University of Alabama at Birmingham, AL, USA
| | - André Leier
- Department of Genetics, School of Medicine, University of Alabama at Birmingham, AL, USA,Department of Cell, Developmental and Integrative Biology, School of Medicine, University of Alabama at Birmingham, AL, USA
| | - Morihiro Hayashida
- National Institute of Technology, Matsue College, Matsue, Shimane, Japan
| | - Tatsuya Akutsu
- Bioinformatics Center, Institute for Chemical Research, Kyoto University, Kyoto, Japan
| | - Yanju Zhang
- School of Computer Science and Information Security, Guilin University of Electronic Technology, Guilin, China
| | - Kuo-Chen Chou
- Gordon Life Science Institute, Boston, MA, USA,Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu, China,Center of Excellence in Genomic Medicine Research (CEGMR), King Abdulaziz University, Jeddah, Saudi Arabia
| | - Joel Selkrig
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany
| | - Tieli Zhou
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | | | - Trevor Lithgow
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, VIC, Australia
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Chen NWG, Serres-Giardi L, Ruh M, Briand M, Bonneau S, Darrasse A, Barbe V, Gagnevin L, Koebnik R, Jacques MA. Horizontal gene transfer plays a major role in the pathological convergence of Xanthomonas lineages on common bean. BMC Genomics 2018; 19:606. [PMID: 30103675 PMCID: PMC6090828 DOI: 10.1186/s12864-018-4975-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Accepted: 07/31/2018] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Host specialization is a hallmark of numerous plant pathogens including bacteria, fungi, oomycetes and viruses. Yet, the molecular and evolutionary bases of host specificity are poorly understood. In some cases, pathological convergence is observed for individuals belonging to distant phylogenetic clades. This is the case for Xanthomonas strains responsible for common bacterial blight of bean, spread across four genetic lineages. All the strains from these four lineages converged for pathogenicity on common bean, implying possible gene convergences and/or sharing of a common arsenal of genes conferring the ability to infect common bean. RESULTS To search for genes involved in common bean specificity, we used a combination of whole-genome analyses without a priori, including a genome scan based on k-mer search. Analysis of 72 genomes from a collection of Xanthomonas pathovars unveiled 115 genes bearing DNA sequences specific to strains responsible for common bacterial blight, including 20 genes located on a plasmid. Of these 115 genes, 88 were involved in successive events of horizontal gene transfers among the four genetic lineages, and 44 contained nonsynonymous polymorphisms unique to the causal agents of common bacterial blight. CONCLUSIONS Our study revealed that host specificity of common bacterial blight agents is associated with a combination of horizontal transfers of genes, and highlights the role of plasmids in these horizontal transfers.
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Affiliation(s)
- Nicolas W. G. Chen
- IRHS, INRA, AGROCAMPUS OUEST, Université d’Angers, SFR4207 QUASAV, 42, rue Georges Morel, 49071 Beaucouzé, France
| | - Laurana Serres-Giardi
- IRHS, INRA, AGROCAMPUS OUEST, Université d’Angers, SFR4207 QUASAV, 42, rue Georges Morel, 49071 Beaucouzé, France
| | - Mylène Ruh
- IRHS, INRA, AGROCAMPUS OUEST, Université d’Angers, SFR4207 QUASAV, 42, rue Georges Morel, 49071 Beaucouzé, France
| | - Martial Briand
- IRHS, INRA, AGROCAMPUS OUEST, Université d’Angers, SFR4207 QUASAV, 42, rue Georges Morel, 49071 Beaucouzé, France
| | - Sophie Bonneau
- IRHS, INRA, AGROCAMPUS OUEST, Université d’Angers, SFR4207 QUASAV, 42, rue Georges Morel, 49071 Beaucouzé, France
| | - Armelle Darrasse
- IRHS, INRA, AGROCAMPUS OUEST, Université d’Angers, SFR4207 QUASAV, 42, rue Georges Morel, 49071 Beaucouzé, France
| | - Valérie Barbe
- CEA/DSV/IG/Genoscope, 2 rue Gaston Crémieux, BP5706, 91057 Evry, France
| | - Lionel Gagnevin
- CIRAD, UMR PVBMT, F-97410 Saint-Pierre, La Réunion France
- IRD, CIRAD, Université de Montpellier, IPME, Montpellier, France
| | - Ralf Koebnik
- IRD, CIRAD, Université de Montpellier, IPME, Montpellier, France
| | - Marie-Agnès Jacques
- IRHS, INRA, AGROCAMPUS OUEST, Université d’Angers, SFR4207 QUASAV, 42, rue Georges Morel, 49071 Beaucouzé, France
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Effector Gene xopAE of Xanthomonas euvesicatoria 85-10 Is Part of an Operon and Encodes an E3 Ubiquitin Ligase. J Bacteriol 2018; 200:JB.00104-18. [PMID: 29784884 DOI: 10.1128/jb.00104-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/13/2018] [Indexed: 01/08/2023] Open
Abstract
The type III effector XopAE from the Xanthomonas euvesicatoria strain 85-10 was previously shown to inhibit plant immunity and enhance pathogen-induced disease symptoms. Evolutionary analysis of 60 xopAE alleles (AEal) revealed that the xopAE locus is conserved in multiple Xanthomonas species. The majority of xopAE alleles (55 out of 60) comprise a single open reading frame (ORF) (xopAE), while in 5 alleles, including AEal 37 of the X. euvesicatoria 85-10 strain, a frameshift splits the locus into two ORFs (hpaF and a truncated xopAE). To test whether the second ORF of AEal 37 (xopAE85-10 ) is translated, we examined expression of yellow fluorescent protein (YFP) fused downstream to truncated or mutant forms of the locus in Xanthomonas bacteria. YFP fluorescence was detected at maximal levels when the reporter was in proximity to an internal ribosome binding site upstream of a rare ATT start codon in the xopAE85-10 ORF but was severely reduced when these elements were abolished. In agreement with the notion that xopAE85-10 is a functional gene, its protein product was translocated into plant cells by the type III secretion system, and translocation was dependent on its upstream ORF, hpaF Homology modeling predicted that XopAE85-10 contains an E3 ligase XL box domain at the C terminus, and in vitro assays demonstrated that this domain displays monoubiquitination activity. Remarkably, the XL box was essential for XopAE85-10 to inhibit pathogen-associated molecular pattern (PAMP)-induced gene expression in Arabidopsis protoplasts. Together, these results indicate that the xopAE85-10 gene resides in a functional operon, which utilizes the alternative start codon ATT and encodes a novel XL box E3 ligase.IMPORTANCEXanthomonas bacteria utilize a type III secretion system to cause disease in many crops. This study provides insights into the evolution, translocation, and biochemical function of the XopAE type III secreted effector, contributing to the understanding of Xanthomonas-host interactions. We establish XopAE as a core effector of seven Xanthomonas species and elucidate the evolution of the Xanthomonas euvesicatoriaxopAE locus, which contains an operon encoding a truncated effector. Our findings indicate that this operon evolved from the split of a multidomain gene into two ORFs that conserved the original domain function. Analysis of xopAE85-10 translation provides the first evidence for translation initiation from an ATT codon in Xanthomonas Our data demonstrate that XopAE85-10 is an XL box E3 ubiquitin ligase and provide insights into the structure and function of this effector family.
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Chalupowicz L, Nissan G, Brandl MT, McClelland M, Sessa G, Popov G, Barash I, Manulis-Sasson S. Assessing the Ability of Salmonella enterica to Translocate Type III Effectors Into Plant Cells. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:233-239. [PMID: 28952399 DOI: 10.1094/mpmi-07-17-0166-r] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Salmonella enterica serovar Typhimurium, a human enteric pathogen, has the ability to multiply and survive endophytically in plants. Genes encoding the type III secretion system (T3SS) or its effectors (T3Es) may contribute to its colonization. Two reporter plasmids for T3E translocation into plant cells that are based on hypersensitive response domains of avirulence proteins from the Pantoea agglomerans-beet and Xanthomonas euvesicatoria-pepper pathosystems were employed in this study to investigate the role of T3Es in the interaction of Salmonella ser. Typhimurium 14028 with plants. The T3Es of Salmonella ser. Typhimurium, SipB and SifA, which are translocated into animal cells, could not be delivered by Salmonella ser. Typhimurium into cells of beet roots or pepper leaves. In contrast, these effectors were translocated into plant cells by the phytopathogenic bacteria P. agglomerans pv. betae, Erwinia amylovora, and X. euvesicatoria. Similarly, HsvG, a T3E of P. agglomerans pv. gypsophilae, and XopAU of X. euvesicatoria could be translocated into beet roots and pepper leaves, respectively, by the plant pathogens but not by Salmonella ser. Typhimurium. Mutations in Salmonella ser. Typhimurium T3SS genes invA, ssaV, sipB, or sifA, did not affect its endophytic colonization of lettuce leaves, supporting the notion that S. enterica cannot translocate T3Es into plant cells.
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Affiliation(s)
- Laura Chalupowicz
- 1 Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, Rishon LeZion 7528809, Israel
| | - Gal Nissan
- 1 Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, Rishon LeZion 7528809, Israel
- 2 School of Plant Sciences and Food Security, Faculty of Life Sciences, Tel-Aviv 69978, Israel
| | - Maria T Brandl
- 3 Produce Safety and Microbiology Research Unit, USDA, ARS, WRRC, 800 Buchanan St., Albany, CA 94710, U.S.A.; and
| | - Michael McClelland
- 4 Department of Microbiology, School of Medicine, University of California, Irvine, CA 92697-4025, U.S.A
| | - Guido Sessa
- 2 School of Plant Sciences and Food Security, Faculty of Life Sciences, Tel-Aviv 69978, Israel
| | - Georgy Popov
- 2 School of Plant Sciences and Food Security, Faculty of Life Sciences, Tel-Aviv 69978, Israel
| | - Isaac Barash
- 2 School of Plant Sciences and Food Security, Faculty of Life Sciences, Tel-Aviv 69978, Israel
| | - Shulamit Manulis-Sasson
- 1 Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, Rishon LeZion 7528809, Israel
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Nissan G, Gershovits M, Morozov M, Chalupowicz L, Sessa G, Manulis‐Sasson S, Barash I, Pupko T. Revealing the inventory of type III effectors in Pantoea agglomerans gall-forming pathovars using draft genome sequences and a machine-learning approach. MOLECULAR PLANT PATHOLOGY 2018; 19:381-392. [PMID: 28019708 PMCID: PMC6638007 DOI: 10.1111/mpp.12528] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 12/06/2016] [Accepted: 12/14/2016] [Indexed: 05/03/2023]
Abstract
Pantoea agglomerans, a widespread epiphytic bacterium, has evolved into a hypersensitive response and pathogenicity (hrp)-dependent and host-specific gall-forming pathogen by the acquisition of a pathogenicity plasmid containing a type III secretion system (T3SS) and its effectors (T3Es). Pantoea agglomerans pv. betae (Pab) elicits galls on beet (Beta vulgaris) and gypsophila (Gypsophila paniculata), whereas P. agglomerans pv. gypsophilae (Pag) incites galls on gypsophila and a hypersensitive response (HR) on beet. Draft genome sequences were generated and employed in combination with a machine-learning approach and a translocation assay into beet roots to identify the pools of T3Es in the two pathovars. The genomes of the sequenced Pab4188 and Pag824-1 strains have a similar size (∼5 MB) and GC content (∼55%). Mutational analysis revealed that, in Pab4188, eight T3Es (HsvB, HsvG, PseB, DspA/E, HopAY1, HopX2, HopAF1 and HrpK) contribute to pathogenicity on beet and gypsophila. In Pag824-1, nine T3Es (HsvG, HsvB, PthG, DspA/E, HopAY1, HopD1, HopX2, HopAF1 and HrpK) contribute to pathogenicity on gypsophila, whereas the PthG effector triggers HR on beet. HsvB, HsvG, PthG and PseB appear to endow pathovar specificities to Pab and Pag, and no homologous T3Es were identified for these proteins in other phytopathogenic bacteria. Conversely, the remaining T3Es contribute to the virulence of both pathovars, and homologous T3Es were found in other phytopathogenic bacteria. Remarkably, HsvG and HsvB, which act as host-specific transcription factors, displayed the largest contribution to disease development.
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Affiliation(s)
- Gal Nissan
- Department of Molecular Biology and Ecology of Plants, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterRishonLeZion7528809Israel
| | - Michael Gershovits
- Department of Cell Research and Immunology, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
| | - Michael Morozov
- Department of Molecular Biology and Ecology of Plants, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterRishonLeZion7528809Israel
| | - Laura Chalupowicz
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterRishonLeZion7528809Israel
| | - Guido Sessa
- Department of Molecular Biology and Ecology of Plants, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
| | - Shulamit Manulis‐Sasson
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterRishonLeZion7528809Israel
| | - Isaac Barash
- Department of Molecular Biology and Ecology of Plants, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
| | - Tal Pupko
- Department of Cell Research and Immunology, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
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Teper D, Girija AM, Bosis E, Popov G, Savidor A, Sessa G. The Xanthomonas euvesicatoria type III effector XopAU is an active protein kinase that manipulates plant MAP kinase signaling. PLoS Pathog 2018; 14:e1006880. [PMID: 29377937 PMCID: PMC5805367 DOI: 10.1371/journal.ppat.1006880] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 02/08/2018] [Accepted: 01/15/2018] [Indexed: 11/19/2022] Open
Abstract
The Gram-negative bacterium Xanthomonas euvesicatoria (Xe) is the causal agent of bacterial spot disease of pepper and tomato. Xe delivers effector proteins into host cells through the type III secretion system to promote disease. Here, we show that the Xe effector XopAU, which is conserved in numerous Xanthomonas species, is a catalytically active protein kinase and contributes to the development of disease symptoms in pepper plants. Agrobacterium-mediated expression of XopAU in host and non-host plants activated typical defense responses, including MAP kinase phosphorylation, accumulation of pathogenesis-related (PR) proteins and elicitation of cell death, that were dependent on the kinase activity of the effector. XopAU-mediated cell death was not dependent on early signaling components of effector-triggered immunity and was also observed when the effector was delivered into pepper leaves by Xanthomonas campestris pv. campestris, but not by Xe. Protein-protein interaction studies in yeast and in planta revealed that XopAU physically interacts with components of plant immunity-associated MAP kinase cascades. Remarkably, XopAU directly phosphorylated MKK2 in vitro and enhanced its phosphorylation at multiple sites in planta. Consistent with the notion that MKK2 is a target of XopAU, silencing of the MKK2 homolog or overexpression of the catalytically inactive mutant MKK2K99R in N. benthamiana plants reduced XopAU-mediated cell death and MAPK phosphorylation. Furthermore, yeast co-expressing XopAU and MKK2 displayed reduced growth and this phenotype was dependent on the kinase activity of both proteins. Together, our results support the conclusion that XopAU contributes to Xe disease symptoms in pepper plants and manipulates host MAPK signaling through phosphorylation and activation of MKK2.
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Affiliation(s)
- Doron Teper
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel
| | | | - Eran Bosis
- Department of Biotechnology Engineering, ORT Braude College, Karmiel, Israel
| | - Georgy Popov
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel
| | - Alon Savidor
- The Nancy & Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot, Israel
| | - Guido Sessa
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel
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40
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Scheibner F, Marillonnet S, Büttner D. The TAL Effector AvrBs3 from Xanthomonas campestris pv. vesicatoria Contains Multiple Export Signals and Can Enter Plant Cells in the Absence of the Type III Secretion Translocon. Front Microbiol 2017; 8:2180. [PMID: 29170655 PMCID: PMC5684485 DOI: 10.3389/fmicb.2017.02180] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 10/24/2017] [Indexed: 12/27/2022] Open
Abstract
Pathogenicity of the Gram-negative plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria depends on a type III secretion (T3S) system which translocates effector proteins into plant cells. Effector protein delivery is controlled by the T3S chaperone HpaB, which presumably escorts effector proteins to the secretion apparatus. One intensively studied effector is the transcription activator-like (TAL) effector AvrBs3, which binds to promoter sequences of plant target genes and activates plant gene expression. It was previously reported that type III-dependent delivery of AvrBs3 depends on the N-terminal protein region. The signals that control T3S and translocation of AvrBs3, however, have not yet been characterized. In the present study, we show that T3S and translocation of AvrBs3 depend on the N-terminal 10 and 50 amino acids, respectively. Furthermore, we provide experimental evidence that additional signals in the N-terminal 30 amino acids and the region between amino acids 64 and 152 promote translocation of AvrBs3 in the absence of HpaB. Unexpectedly, in vivo translocation assays revealed that AvrBs3 is delivered into plant cells even in the absence of HrpF, which is the predicted channel-forming component of the T3S translocon in the plant plasma membrane. The presence of HpaB- and HrpF-independent transport routes suggests that the delivery of AvrBs3 is initiated during early stages of the infection process, presumably before the activation of HpaB or the insertion of the translocon into the plant plasma membrane.
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Affiliation(s)
- Felix Scheibner
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, Halle, Germany
| | | | - Daniela Büttner
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, Halle, Germany
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41
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Merda D, Briand M, Bosis E, Rousseau C, Portier P, Barret M, Jacques MA, Fischer-Le Saux M. Ancestral acquisitions, gene flow and multiple evolutionary trajectories of the type three secretion system and effectors in Xanthomonas plant pathogens. Mol Ecol 2017; 26:5939-5952. [PMID: 28869687 PMCID: PMC7168496 DOI: 10.1111/mec.14343] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 08/03/2017] [Accepted: 08/05/2017] [Indexed: 12/13/2022]
Abstract
Deciphering the evolutionary history and transmission patterns of virulence determinants is necessary to understand the emergence of novel pathogens. The main virulence determinant of most pathogenic proteobacteria is the type three secretion system (T3SS). The Xanthomonas genus includes bacteria responsible for numerous epidemics in agroecosystems worldwide and represents a major threat to plant health. The main virulence factor of Xanthomonas is the Hrp2 family T3SS; however, this system is not conserved in all strains and it has not been previously determined whether the distribution of T3SS in this bacterial genus has resulted from losses or independent acquisitions. Based on comparative genomics of 82 genome sequences representing the diversity of the genus, we have inferred three ancestral acquisitions of the Hrp2 cluster during Xanthomonas evolution followed by subsequent losses in some commensal strains and re‐acquisition in some species. While mutation was the main force driving polymorphism at the gene level, interspecies homologous recombination of large fragments expanding through several genes shaped Hrp2 cluster polymorphism. Horizontal gene transfer of the entire Hrp2 cluster also occurred. A reduced core effectome composed of xopF1, xopM, avrBs2 and xopR was identified that may allow commensal strains overcoming plant basal immunity. In contrast, stepwise accumulation of numerous type 3 effector genes was shown in successful pathogens responsible for epidemics. Our data suggest that capacity to intimately interact with plants through T3SS would be an ancestral trait of xanthomonads. Since its acquisition, T3SS has experienced a highly dynamic evolutionary history characterized by intense gene flux between species that may reflect its role in host adaptation.
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Affiliation(s)
- Déborah Merda
- IRHS, Agrocampus-Ouest, INRA, Université d'Angers, SFR 4207 QuaSaV, Beaucouzé, France
| | - Martial Briand
- IRHS, Agrocampus-Ouest, INRA, Université d'Angers, SFR 4207 QuaSaV, Beaucouzé, France
| | - Eran Bosis
- Department of Biotechnology Engineering, ORT Braude College, Karmiel, Israel
| | - Céline Rousseau
- IRHS, Agrocampus-Ouest, INRA, Université d'Angers, SFR 4207 QuaSaV, Beaucouzé, France
| | - Perrine Portier
- IRHS, Agrocampus-Ouest, INRA, Université d'Angers, SFR 4207 QuaSaV, Beaucouzé, France
| | - Matthieu Barret
- IRHS, Agrocampus-Ouest, INRA, Université d'Angers, SFR 4207 QuaSaV, Beaucouzé, France
| | - Marie-Agnès Jacques
- IRHS, Agrocampus-Ouest, INRA, Université d'Angers, SFR 4207 QuaSaV, Beaucouzé, France
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Falahi Charkhabi N, Booher NJ, Peng Z, Wang L, Rahimian H, Shams-Bakhsh M, Liu Z, Liu S, White FF, Bogdanove AJ. Complete Genome Sequencing and Targeted Mutagenesis Reveal Virulence Contributions of Tal2 and Tal4b of Xanthomonas translucens pv. undulosa ICMP11055 in Bacterial Leaf Streak of Wheat. Front Microbiol 2017; 8:1488. [PMID: 28848509 PMCID: PMC5554336 DOI: 10.3389/fmicb.2017.01488] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/24/2017] [Indexed: 12/31/2022] Open
Abstract
Bacterial leaf streak caused by Xanthomonas translucens pv. undulosa (Xtu) is an important disease of wheat (Triticum aestivum) and barley (Hordeum vulgare) worldwide. Transcription activator-like effectors (TALEs) play determinative roles in many of the plant diseases caused by the different species and pathovars of Xanthomonas, but their role in this disease has not been characterized. ICMP11055 is a highly virulent Xtu strain from Iran. The aim of this study was to better understand genetic diversity of Xtu and to assess the role of TALEs in bacterial leaf streak of wheat by comparing the genome of this strain to the recently completely sequenced genome of a U.S. Xtu strain, and to several other draft X. translucens genomes, and by carrying out mutational analyses of the TALE (tal) genes the Iranian strain might harbor. The ICMP11055 genome, including its repeat-rich tal genes, was completely sequenced using single molecule, real-time technology (Pacific Biosciences). It consists of a single circular chromosome of 4,561,583 bp, containing 3,953 genes. Whole genome alignment with the genome of the United States Xtu strain XT4699 showed two major re-arrangements, nine genomic regions unique to ICMP11055, and one region unique to XT4699. ICMP110055 harbors 26 non-TALE type III effector genes and seven tal genes, compared to 25 and eight for XT4699. The tal genes occur singly or in pairs across five scattered loci. Four are identical to tal genes in XT4699. In addition to common repeat-variable diresidues (RVDs), the tal genes of ICMP11055, like those of XT4699, encode several RVDs rarely observed in Xanthomonas, including KG, NF, Y∗, YD, and YK. Insertion and deletion mutagenesis of ICMP11055 tal genes followed by genetic complementation analysis in wheat cv. Chinese Spring revealed that Tal2 and Tal4b of ICMP11055 each contribute individually to the extent of disease caused by this strain. A largely conserved ortholog of tal2 is present in XT4699, but for tal4b, only a gene with partial, fragmented RVD sequence similarity can be found. Our results lay the foundation for identification of important host genes activated by Xtu TALEs as targets for the development of disease resistant varieties.
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Affiliation(s)
- Nargues Falahi Charkhabi
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, IthacaNY, United States.,Department of Plant Pathology, Tarbiat Modares UniversityTehran, Iran
| | - Nicholas J Booher
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, IthacaNY, United States
| | - Zhao Peng
- Department of Plant Pathology, Kansas State University, ManhattanKS, United States.,Department of Plant Pathology, University of Florida, GainesvilleFL, United States
| | - Li Wang
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, IthacaNY, United States
| | - Heshmat Rahimian
- Department of Plant Protection, Sari Agricultural Science and Natural Resources UniversitySari, Iran
| | | | - Zhaohui Liu
- Department of Plant Pathology, North Dakota State University, FargoND, United States
| | - Sanzhen Liu
- Department of Plant Pathology, Kansas State University, ManhattanKS, United States
| | - Frank F White
- Department of Plant Pathology, Kansas State University, ManhattanKS, United States.,Department of Plant Pathology, University of Florida, GainesvilleFL, United States
| | - Adam J Bogdanove
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, IthacaNY, United States
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Nakano M, Oda K, Mukaihara T. Ralstonia solanacearum novel E3 ubiquitin ligase (NEL) effectors RipAW and RipAR suppress pattern-triggered immunity in plants. MICROBIOLOGY (READING, ENGLAND) 2017; 163:992-1002. [PMID: 28708051 DOI: 10.1099/mic.0.000495] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Ralstonia solanacearum is the causal agent of bacterial wilt in solanaceous crops. This pathogen injects more than 70 effector proteins into host plant cells via the Hrp type III secretion system to cause a successful infection. However, the function of these effectors in plant cells, especially in the suppression of plant immunity, remains largely unknown. In this study, we characterized two Ralstonia solanacearum effectors, RipAW and RipAR, which share homology with the IpaH family of effectors from animal and plant pathogenic bacteria, that have a novel E3 ubiquitin ligase (NEL) domain. Recombinant RipAW and RipAR show E3 ubiquitin ligase activity in vitro. RipAW and RipAR localized to the cytoplasm of plant cells and significantly suppressed pattern-triggered immunity (PTI) responses such as the production of reactive oxygen species and the expression of defence-related genes when expressed in leaves of Nicotiana benthamiana. Mutation in the conserved cysteine residue in the NEL domain of RipAW completely abolished the E3 ubiquitin ligase activity in vitro and the ability to suppress PTI responses in plant leaves. These results indicate that RipAW suppresses plant PTI responses through the E3 ubiquitin ligase activity. Unlike other members of the IpaH family of effectors, RipAW and RipAR had no leucine-rich repeat motifs in their amino acid sequences. A conserved C-terminal region of RipAW is indispensable for PTI suppression. Transgenic Arabidopsis plants expressing RipAW and RipAR showed increased disease susceptibility, suggesting that RipAW and RipAR contribute to bacterial virulence in plants.
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Affiliation(s)
- Masahito Nakano
- Research Institute for Biological Sciences, Okayama (RIBS), 7549-1 Yoshikawa, Kibichuo-cho, Okayama 716-1241, Japan
| | - Kenji Oda
- Research Institute for Biological Sciences, Okayama (RIBS), 7549-1 Yoshikawa, Kibichuo-cho, Okayama 716-1241, Japan
| | - Takafumi Mukaihara
- Research Institute for Biological Sciences, Okayama (RIBS), 7549-1 Yoshikawa, Kibichuo-cho, Okayama 716-1241, Japan
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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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Popov G, Fraiture M, Brunner F, Sessa G. Multiple Xanthomonas euvesicatoria Type III Effectors Inhibit flg22-Triggered Immunity. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2016; 29:651-60. [PMID: 27529660 DOI: 10.1094/mpmi-07-16-0137-r] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Xanthomonas euvesicatoria is the causal agent of bacterial spot disease in pepper and tomato. X. euvesicatoria bacteria interfere with plant cellular processes by injecting effector proteins into host cells through the type III secretion (T3S) system. About 35 T3S effectors have been identified in X. euvesicatoria 85-10, and a few of them were implicated in suppression of pattern-triggered immunity (PTI). We used an Arabidopsis thaliana pathogen-free protoplast-based assay to identify X. euvesicatoria 85-10 effectors that interfere with PTI signaling induced by the bacterial peptide flg22. Of 33 tested effectors, 17 inhibited activation of a PTI-inducible promoter. Among them, nine effectors also interfered with activation of an abscisic acid-inducible promoter. However, effectors that inhibited flg22-induced signaling did not affect phosphorylation of mitogen-activated protein (MAP) kinases acting downstream of flg22 perception. Further investigation of selected effectors revealed that XopAJ, XopE2, and XopF2 inhibited activation of a PTI-inducible promoter by the bacterial peptide elf18 in Arabidopsis protoplasts and by flg22 in tomato protoplasts. The effectors XopF2, XopE2, XopAP, XopAE, XopH, and XopAJ inhibited flg22-induced callose deposition in planta and enhanced disease symptoms caused by attenuated Pseudomonas syringae bacteria. Finally, selected effectors were found to localize to various plant subcellular compartments. These results indicate that X. euvesicatoria bacteria utilize multiple T3S effectors to suppress flg22-induced signaling acting downstream or in parallel to MAP kinase cascades and suggest they act through different molecular mechanisms.
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Affiliation(s)
- Georgy Popov
- 1 Department of Molecular Biology and Ecology of Plants, Tel-Aviv University, 69978 Tel-Aviv, Israel; and
| | - Malou Fraiture
- 2 Department of Biochemistry, Centre for Plant Molecular Biology, Eberhard Karls University, Auf der Morgenstelle 32, D-72076 Tübingen, Germany
| | - Frederic Brunner
- 2 Department of Biochemistry, Centre for Plant Molecular Biology, Eberhard Karls University, Auf der Morgenstelle 32, D-72076 Tübingen, Germany
| | - Guido Sessa
- 1 Department of Molecular Biology and Ecology of Plants, Tel-Aviv University, 69978 Tel-Aviv, Israel; and
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Sonah H, Deshmukh RK, Bélanger RR. Computational Prediction of Effector Proteins in Fungi: Opportunities and Challenges. FRONTIERS IN PLANT SCIENCE 2016; 7:126. [PMID: 26904083 PMCID: PMC4751359 DOI: 10.3389/fpls.2016.00126] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/23/2016] [Indexed: 05/20/2023]
Abstract
Effector proteins are mostly secretory proteins that stimulate plant infection by manipulating the host response. Identifying fungal effector proteins and understanding their function is of great importance in efforts to curb losses to plant diseases. Recent advances in high-throughput sequencing technologies have facilitated the availability of several fungal genomes and 1000s of transcriptomes. As a result, the growing amount of genomic information has provided great opportunities to identify putative effector proteins in different fungal species. There is little consensus over the annotation and functionality of effector proteins, and mostly small secretory proteins are considered as effector proteins, a concept that tends to overestimate the number of proteins involved in a plant-pathogen interaction. With the characterization of Avr genes, criteria for computational prediction of effector proteins are becoming more efficient. There are 100s of tools available for the identification of conserved motifs, signature sequences and structural features in the proteins. Many pipelines and online servers, which combine several tools, are made available to perform genome-wide identification of effector proteins. In this review, available tools and pipelines, their strength and limitations for effective identification of fungal effector proteins are discussed. We also present an exhaustive list of classically secreted proteins along with their key conserved motifs found in 12 common plant pathogens (11 fungi and one oomycete) through an analytical pipeline.
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Affiliation(s)
| | | | - Richard R. Bélanger
- Département de Phytologie, Faculté des Sciences de l’Agriculture et de l’Alimentation, Centre de Recherche en Horticulture, Université Laval, QuébecQC, Canada
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Adlung N, Prochaska H, Thieme S, Banik A, Blüher D, John P, Nagel O, Schulze S, Gantner J, Delker C, Stuttmann J, Bonas U. Non-host Resistance Induced by the Xanthomonas Effector XopQ Is Widespread within the Genus Nicotiana and Functionally Depends on EDS1. FRONTIERS IN PLANT SCIENCE 2016; 7:1796. [PMID: 27965697 PMCID: PMC5127841 DOI: 10.3389/fpls.2016.01796] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 11/15/2016] [Indexed: 05/18/2023]
Abstract
Most Gram-negative plant pathogenic bacteria translocate effector proteins (T3Es) directly into plant cells via a conserved type III secretion system, which is essential for pathogenicity in susceptible plants. In resistant plants, recognition of some T3Es is mediated by corresponding resistance (R) genes or R proteins and induces effector triggered immunity (ETI) that often results in programmed cell death reactions. The identification of R genes and understanding their evolution/distribution bears great potential for the generation of resistant crop plants. We focus on T3Es from Xanthomonas campestris pv. vesicatoria (Xcv), the causal agent of bacterial spot disease on pepper and tomato plants. Here, 86 Solanaceae lines mainly of the genus Nicotiana were screened for phenotypical reactions after Agrobacterium tumefaciens-mediated transient expression of 21 different Xcv effectors to (i) identify new plant lines for T3E characterization, (ii) analyze conservation/evolution of putative R genes and (iii) identify promising plant lines as repertoire for R gene isolation. The effectors provoked different reactions on closely related plant lines indicative of a high variability and evolution rate of potential R genes. In some cases, putative R genes were conserved within a plant species but not within superordinate phylogenetical units. Interestingly, the effector XopQ was recognized by several Nicotiana spp. lines, and Xcv infection assays revealed that XopQ is a host range determinant in many Nicotiana species. Non-host resistance against Xcv and XopQ recognition in N. benthamiana required EDS1, strongly suggesting the presence of a TIR domain-containing XopQ-specific R protein in these plant lines. XopQ is a conserved effector among most xanthomonads, pointing out the XopQ-recognizing RxopQ as candidate for targeted crop improvement.
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Affiliation(s)
- Norman Adlung
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
- *Correspondence: Norman Adlung
| | - Heike Prochaska
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Sabine Thieme
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Anne Banik
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Doreen Blüher
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Peter John
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Oliver Nagel
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Sebastian Schulze
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Johannes Gantner
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Carolin Delker
- Department of Crop Physiology, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-WittenbergHalle, Germany
| | - Johannes Stuttmann
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Ulla Bonas
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
- Ulla Bonas
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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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