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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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Effectors of Puccinia striiformis f. sp. tritici Suppressing the Pathogenic-Associated Molecular Pattern-Triggered Immune Response Were Screened by Transient Expression of Wheat Protoplasts. Int J Mol Sci 2021; 22:ijms22094985. [PMID: 34067160 PMCID: PMC8125866 DOI: 10.3390/ijms22094985] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/29/2021] [Accepted: 05/03/2021] [Indexed: 11/17/2022] Open
Abstract
Puccinia striiformis f. sp. tritici (Pst) is an important pathogen of wheat (Triticum aestivum L.) stripe rust, and the effector protein secreted by haustoria is a very important component involved in the pathogenic process. Although the candidate effector proteins secreted by Pst haustoria have been predicted to be abundant, few have been functionally validated. Our study confirmed that chitin and flg22 could be used as elicitors of the pathogenic-associated molecular pattern-triggered immune (PTI) reaction in wheat leaves and that TaPr-1-14 could be used as a marker gene to detect the PTI reaction. In addition, the experimental results were consistent in wheat protoplasts. A rapid and efficient method for screening and identifying the effector proteins of Pst was established by using the wheat protoplast transient expression system. Thirty-nine Pst haustorial effector genes were successfully cloned and screened for expression in the protoplast. We identified three haustorial effector proteins, PSEC2, PSEC17, and PSEC45, that may inhibit the response of wheat to PTI. These proteins are localized in the somatic cytoplasm and nucleus of wheat protoplasts and are highly expressed during the infection and parasitism of wheat.
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Computational prediction of secreted proteins in gram-negative bacteria. Comput Struct Biotechnol J 2021; 19:1806-1828. [PMID: 33897982 PMCID: PMC8047123 DOI: 10.1016/j.csbj.2021.03.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 03/18/2021] [Accepted: 03/18/2021] [Indexed: 12/29/2022] Open
Abstract
Gram-negative bacteria harness multiple protein secretion systems and secrete a large proportion of the proteome. Proteins can be exported to periplasmic space, integrated into membrane, transported into extracellular milieu, or translocated into cytoplasm of contacting cells. It is important for accurate, genome-wide annotation of the secreted proteins and their secretion pathways. In this review, we systematically classified the secreted proteins according to the types of secretion systems in Gram-negative bacteria, summarized the known features of these proteins, and reviewed the algorithms and tools for their prediction.
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Prathiviraj R, Chellapandi P. Deciphering Molecular Virulence Mechanism of Mycobacterium tuberculosis Dop isopeptidase Based on Its Sequence-Structure-Function Linkage. Protein J 2020; 39:33-45. [PMID: 31760575 DOI: 10.1007/s10930-019-09876-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The pupylation pathway marks proteins for prokaryotic ubiquitin-like protein (Pup)-proteasomal degradation and survival strategy of mycobacteria inside of the host macrophages. Deamidase of Pup (Dop) plays a central role in the pupylation pathway. It is still a matter of investigation to know the function of Dop in virulence of mycobacterial lineage. Hence, the present study was intended to describe the sequence-structure-function-virulence link of Dop for understanding the molecular virulence mechanism of Mycobacterium tuberculosis H37Rv (Mtb). Phylogenetic analysis of this study indicated that Dop has extensively diverged across the proteasome-harboring bacteria. The functional part of Dop was converged across the pathogenic mycobacterial lineage. The genome-wide analysis pointed out that the pupylation gene locus was identical to each other, but its genome neighborhood differed from species to species. Molecular modeling and dynamic studies proved that the predicted structure of Mtb Dop was energetically stable and low conformational freedom. Moreover, evolutionary constraints in Mtb Dop were intensively analyzed for inferring its sequence-structure-function relationships for the full virulence of Mtb. It indicated that evolutionary optimization was extensively required to stabilize its local structural environment at the side chains of mutable residues. The sequence-structure-function-virulence link of Dop might have retained in Mtb by reordering hydrophobic and hydrogen bonding patterns in the local structural environment. Thus, the results of our study provide a quest to understand the molecular virulence and pathogenesis mechanisms of Mtb during the infection process.
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Affiliation(s)
- R Prathiviraj
- Molecular Systems Engineering Lab, Department of Bioinformatics, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, 620024, India
| | - P Chellapandi
- Molecular Systems Engineering Lab, Department of Bioinformatics, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, 620024, India.
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Zalguizuri A, Caetano-Anollés G, Lepek VC. Phylogenetic profiling, an untapped resource for the prediction of secreted proteins and its complementation with sequence-based classifiers in bacterial type III, IV and VI secretion systems. Brief Bioinform 2020; 20:1395-1402. [PMID: 29394318 DOI: 10.1093/bib/bby009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 01/15/2018] [Indexed: 12/29/2022] Open
Abstract
In the establishment and maintenance of the interaction between pathogenic or symbiotic bacteria with a eukaryotic organism, protein substrates of specialized bacterial secretion systems called effectors play a critical role once translocated into the host cell. Proteins are also secreted to the extracellular medium by free-living bacteria or directly injected into other competing organisms to hinder or kill. In this work, we explore an approach based on the evolutionary dependence that most of the effectors maintain with their specific secretion system that analyzes the co-occurrence of any orthologous protein group and their corresponding secretion system across multiple genomes. We compared and complemented our methodology with sequence-based machine learning prediction tools for the type III, IV and VI secretion systems. Finally, we provide the predictive results for the three secretion systems in 1606 complete genomes at http://www.iib.unsam.edu.ar/orgsissec/.
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Abstract
An accurate and complete roster of the Type III effector (T3E) proteins translocated by the P. syringae Type III secretion system (T3SS) into host cells is critical to understanding the pathogen's interactions with plants. The adenylate cyclase (Cya) reporter offers a highly sensitive and robust assay for monitoring the translocation of T3Es. T3Es are fused to the calmodulin-dependent adenylate-cyclase domain of CyaA. The T3E targets Cya for translocation through the T3SS into the host cell at which point it is activated by calmodulin and converts adenosine triphosphate into cyclic adenosine monophosphate (cAMP). The T3SS translocation-dependent increase in cAMP concentration in plant cells is then measured with an enzyme-linked immunosorbent assay kit. The Cya reporter can be used to determine whether a candidate protein is translocated by T3SS or to measure relative levels of T3SS translocation in a semiquantitative manner.
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Büttner D. Behind the lines-actions of bacterial type III effector proteins in plant cells. FEMS Microbiol Rev 2018; 40:894-937. [PMID: 28201715 PMCID: PMC5091034 DOI: 10.1093/femsre/fuw026] [Citation(s) in RCA: 175] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 03/31/2016] [Accepted: 07/03/2016] [Indexed: 01/30/2023] Open
Abstract
Pathogenicity of most Gram-negative plant-pathogenic bacteria depends on the type III secretion (T3S) system, which translocates bacterial effector proteins into plant cells. Type III effectors modulate plant cellular pathways to the benefit of the pathogen and promote bacterial multiplication. One major virulence function of type III effectors is the suppression of plant innate immunity, which is triggered upon recognition of pathogen-derived molecular patterns by plant receptor proteins. Type III effectors also interfere with additional plant cellular processes including proteasome-dependent protein degradation, phytohormone signaling, the formation of the cytoskeleton, vesicle transport and gene expression. This review summarizes our current knowledge on the molecular functions of type III effector proteins with known plant target molecules. Furthermore, plant defense strategies for the detection of effector protein activities or effector-triggered alterations in plant targets are discussed.
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Affiliation(s)
- Daniela Büttner
- Genetics Department, Institute of Biology, Martin-Luther University Halle-Wittenberg, Halle (Saale), Germany
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Scheibner F, Hartmann N, Hausner J, Lorenz C, Hoffmeister AK, Büttner D. The Type III Secretion Chaperone HpaB Controls the Translocation of Effector and Noneffector Proteins From Xanthomonas campestris pv. vesicatoria. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:61-74. [PMID: 28771395 DOI: 10.1094/mpmi-06-17-0138-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: 06/07/2023]
Abstract
Pathogenicity of the gram-negative bacterium Xanthomonas campestris pv. vesicatoria depends on a type III secretion (T3S) system, which translocates effector proteins into plant cells. Effector proteins contain N-terminal T3S and translocation signals and interact with the T3S chaperone HpaB, which presumably escorts effectors to the secretion apparatus. The molecular mechanisms underlying the recognition of effectors by the T3S system are not yet understood. In the present study, we analyzed T3S and translocation signals in the type III effectors XopE2 and XopJ from X. campestris pv. vesicatoria. Both effectors contain minimal translocation signals, which are only recognized in the absence of HpaB. Additional N-terminal signals promote translocation of XopE2 and XopJ in the wild-type strain. The results of translocation and interaction studies revealed that the interaction of XopE2 and XopJ with HpaB and a predicted cytoplasmic substrate docking site of the T3S system is not sufficient for translocation. In agreement with this finding, we show that the presence of an artificial HpaB-binding site does not promote translocation of the noneffector XopA in the wild-type strain. Our data, therefore, suggest that the T3S chaperone HpaB not only acts as an escort protein but also controls the recognition of translocation signals.
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Affiliation(s)
- Felix Scheibner
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Nadine Hartmann
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Jens Hausner
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Christian Lorenz
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Anne-Katrin Hoffmeister
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Daniela Büttner
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
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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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Hu Y, Huang H, Cheng X, Shu X, White AP, Stavrinides J, Köster W, Zhu G, Zhao Z, Wang Y. A global survey of bacterial type III secretion systems and their effectors. Environ Microbiol 2017; 19:3879-3895. [DOI: 10.1111/1462-2920.13755] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 04/04/2017] [Indexed: 11/27/2022]
Affiliation(s)
- Yueming Hu
- Department of Cell Biology and Genetics, School of Basic Medical Sciences; Shenzhen University Health Science Center; Shenzhen 518060 P.R. China
| | - He Huang
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology; Chinese Academy of Medical Sciences & Peking Union Medical College; Beijing China
| | - Xi Cheng
- Department of Cell Biology and Genetics, School of Basic Medical Sciences; Shenzhen University Health Science Center; Shenzhen 518060 P.R. China
| | - Xingsheng Shu
- Department of Cell Biology and Genetics, School of Basic Medical Sciences; Shenzhen University Health Science Center; Shenzhen 518060 P.R. China
| | - Aaron P. White
- Vaccine and Infectious Disease Organization; University of Saskatchewan; Saskatoon SK Canada
| | | | - Wolfgang Köster
- Vaccine and Infectious Disease Organization; University of Saskatchewan; Saskatoon SK Canada
| | - Guoqiang Zhu
- College of Veterinary Medicine; Yangzhou University; Yangzhou China
| | - Zhendong Zhao
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology; Chinese Academy of Medical Sciences & Peking Union Medical College; Beijing China
| | - Yejun Wang
- Department of Cell Biology and Genetics, School of Basic Medical Sciences; Shenzhen University Health Science Center; Shenzhen 518060 P.R. China
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Hobbs CK, Porter VL, Stow MLS, Siame BA, Tsang HH, Leung KY. Computational approach to predict species-specific type III secretion system (T3SS) effectors using single and multiple genomes. BMC Genomics 2016; 17:1048. [PMID: 27993130 PMCID: PMC5168842 DOI: 10.1186/s12864-016-3363-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 12/01/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Many gram-negative bacteria use type III secretion systems (T3SSs) to translocate effector proteins into host cells. T3SS effectors can give some bacteria a competitive edge over others within the same environment and can help bacteria to invade the host cells and allow them to multiply rapidly within the host. Therefore, developing efficient methods to identify effectors scattered in bacterial genomes can lead to a better understanding of host-pathogen interactions and ultimately to important medical and biotechnological applications. RESULTS We used 21 genomic and proteomic attributes to create a precise and reliable T3SS effector prediction method called Genome Search for Effectors Tool (GenSET). Five machine learning algorithms were trained on effectors selected from different organisms and a trained (voting) algorithm was then applied to identify other effectors present in the genome testing sets from the same (GenSET Phase 1) or different (GenSET Phase 2) organism. Although a select group of attributes that included the codon adaptation index, probability of expression in inclusion bodies, N-terminal disorder, and G + C content (filtered) were better at discriminating between positive and negative sets, algorithm performance was better when all 21 attributes (unfiltered) were used. Performance scores (sensitivity, specificity and area under the curve) from GenSET Phase 1 were better than those reported for six published methods. More importantly, GenSET Phase 1 ranked more known effectors (70.3%) in the top 40 ranked proteins and predicted 10-80% more effectors than three available programs in three of the four organisms tested. GenSET Phase 2 predicted 43.8% effectors in the top 40 ranked proteins when tested on four related or unrelated organisms. The lower prediction rates from GenSET Phase 2 may be due to the presence of different translocation signals in effectors from different T3SS families. CONCLUSIONS The species-specific GenSET Phase 1 method offers an alternative approach to T3SS effector prediction that can be used with other published programs to improve effector predictions. Additionally, our approach can be applied to predict effectors of other secretion systems as long as these effectors have translocation signals embedded in their sequences.
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Affiliation(s)
- Christopher K Hobbs
- Applied Research Laboratory, Faculty of Natural and Applied Sciences, Trinity Western University, 7600 Glover Road, Langley, BC, Canada, V2Y 1Y1
| | - Vanessa L Porter
- Department of Biology, Faculty of Natural and Applied Sciences, Trinity Western University, 7600 Glover Road, Langley, BC, Canada, V2Y 1Y1
| | - Maxwell L S Stow
- Applied Research Laboratory, Faculty of Natural and Applied Sciences, Trinity Western University, 7600 Glover Road, Langley, BC, Canada, V2Y 1Y1
| | - Bupe A Siame
- Department of Biology, Faculty of Natural and Applied Sciences, Trinity Western University, 7600 Glover Road, Langley, BC, Canada, V2Y 1Y1
| | - Herbert H Tsang
- Applied Research Laboratory, Faculty of Natural and Applied Sciences, Trinity Western University, 7600 Glover Road, Langley, BC, Canada, V2Y 1Y1.
| | - Ka Yin Leung
- Department of Biology, Faculty of Natural and Applied Sciences, Trinity Western University, 7600 Glover Road, Langley, BC, Canada, V2Y 1Y1. .,State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China.
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Scheibner F, Schulz S, Hausner J, Marillonnet S, Büttner D. Type III-Dependent Translocation of HrpB2 by a Nonpathogenic hpaABC Mutant of the Plant-Pathogenic Bacterium Xanthomonas campestris pv. vesicatoria. Appl Environ Microbiol 2016; 82:3331-3347. [PMID: 27016569 PMCID: PMC4959247 DOI: 10.1128/aem.00537-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 03/21/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria employs a type III secretion (T3S) system to translocate effector proteins into plant cells. The T3S apparatus spans both bacterial membranes and is associated with an extracellular pilus and a channel-like translocon in the host plasma membrane. T3S is controlled by the switch protein HpaC, which suppresses secretion and translocation of the predicted inner rod protein HrpB2 and promotes secretion of translocon and effector proteins. We previously reported that HrpB2 interacts with HpaC and the cytoplasmic domain of the inner membrane protein HrcU (C. Lorenz, S. Schulz, T. Wolsch, O. Rossier, U. Bonas, and D. Büttner, PLoS Pathog 4:e1000094, 2008, http://dx.doi.org/10.1371/journal.ppat.1000094). However, the molecular mechanisms underlying the control of HrpB2 secretion are not yet understood. Here, we located a T3S and translocation signal in the N-terminal 40 amino acids of HrpB2. The results of complementation experiments with HrpB2 deletion derivatives revealed that the T3S signal of HrpB2 is essential for protein function. Furthermore, interaction studies showed that the N-terminal region of HrpB2 interacts with the cytoplasmic domain of HrcU, suggesting that the T3S signal of HrpB2 contributes to substrate docking. Translocation of HrpB2 is suppressed not only by HpaC but also by the T3S chaperone HpaB and its secreted regulator, HpaA. Deletion of hpaA, hpaB, and hpaC leads to a loss of pathogenicity but allows the translocation of fusion proteins between the HrpB2 T3S signal and effector proteins into leaves of host and non-host plants. IMPORTANCE The T3S system of the plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria is essential for pathogenicity and delivers effector proteins into plant cells. T3S depends on HrpB2, which is a component of the predicted periplasmic inner rod structure of the secretion apparatus. HrpB2 is secreted during the early stages of the secretion process and interacts with the cytoplasmic domain of the inner membrane protein HrcU. Here, we localized the secretion and translocation signal of HrpB2 in the N-terminal 40 amino acids and show that this region is sufficient for the interaction with the cytoplasmic domain of HrcU. Our results suggest that the T3S signal of HrpB2 is required for the docking of HrpB2 to the secretion apparatus. Furthermore, we provide experimental evidence that the N-terminal region of HrpB2 is sufficient to target effector proteins for translocation in a nonpathogenic X. campestris pv. vesicatoria strain.
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Affiliation(s)
- Felix Scheibner
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Steve Schulz
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Jens Hausner
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | | | - Daniela Büttner
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
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Badet T, Peyraud R, Raffaele S. Common protein sequence signatures associate with Sclerotinia borealis lifestyle and secretion in fungal pathogens of the Sclerotiniaceae. FRONTIERS IN PLANT SCIENCE 2015; 6:776. [PMID: 26442085 DOI: 10.3389/fpls.2015.00776issn=1664-462x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 09/10/2015] [Indexed: 05/25/2023]
Abstract
Fungal plant pathogens produce secreted proteins adapted to function outside fungal cells to facilitate colonization of their hosts. In many cases such as for fungi from the Sclerotiniaceae family the repertoire and function of secreted proteins remains elusive. In the Sclerotiniaceae, whereas Sclerotinia sclerotiorum and Botrytis cinerea are cosmopolitan broad host-range plant pathogens, Sclerotinia borealis has a psychrophilic lifestyle with a low optimal growth temperature, a narrow host range and geographic distribution. To spread successfully, S. borealis must synthesize proteins adapted to function in its specific environment. The search for signatures of adaptation to S. borealis lifestyle may therefore help revealing proteins critical for colonization of the environment by Sclerotiniaceae fungi. Here, we analyzed amino acids usage and intrinsic protein disorder in alignments of groups of orthologous proteins from the three Sclerotiniaceae species. We found that enrichment in Thr, depletion in Glu and Lys, and low disorder frequency in hot loops are significantly associated with S. borealis proteins. We designed an index to report bias in these properties and found that high index proteins were enriched among secreted proteins in the three Sclerotiniaceae fungi. High index proteins were also enriched in function associated with plant colonization in S. borealis, and in in planta-induced genes in S. sclerotiorum. We highlight a novel putative antifreeze protein and a novel putative lytic polysaccharide monooxygenase identified through our pipeline as candidate proteins involved in colonization of the environment. Our findings suggest that similar protein signatures associate with S. borealis lifestyle and with secretion in the Sclerotiniaceae. These signatures may be useful for identifying proteins of interest as targets for the management of plant diseases.
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Affiliation(s)
- Thomas Badet
- Laboratoire des Interactions Plantes-Microorganismes, Institut National de la Recherche Agronomique, UMR441 Castanet-Tolosan, France ; Laboratoire des Interactions Plantes-Microorganismes, Centre National de la Recherche Scientifique, UMR2594 Castanet-Tolosan, France
| | - Rémi Peyraud
- Laboratoire des Interactions Plantes-Microorganismes, Institut National de la Recherche Agronomique, UMR441 Castanet-Tolosan, France ; Laboratoire des Interactions Plantes-Microorganismes, Centre National de la Recherche Scientifique, UMR2594 Castanet-Tolosan, France
| | - Sylvain Raffaele
- Laboratoire des Interactions Plantes-Microorganismes, Institut National de la Recherche Agronomique, UMR441 Castanet-Tolosan, France ; Laboratoire des Interactions Plantes-Microorganismes, Centre National de la Recherche Scientifique, UMR2594 Castanet-Tolosan, France
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Prathiviraj R, Prisilla A, Chellapandi P. Structure–function discrepancy inClostridium botulinumC3 toxin for its rational prioritization as a subunit vaccine. J Biomol Struct Dyn 2015; 34:1317-29. [DOI: 10.1080/07391102.2015.1078745] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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15
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Badet T, Peyraud R, Raffaele S. Common protein sequence signatures associate with Sclerotinia borealis lifestyle and secretion in fungal pathogens of the Sclerotiniaceae. FRONTIERS IN PLANT SCIENCE 2015; 6:776. [PMID: 26442085 PMCID: PMC4585107 DOI: 10.3389/fpls.2015.00776] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 09/10/2015] [Indexed: 05/04/2023]
Abstract
Fungal plant pathogens produce secreted proteins adapted to function outside fungal cells to facilitate colonization of their hosts. In many cases such as for fungi from the Sclerotiniaceae family the repertoire and function of secreted proteins remains elusive. In the Sclerotiniaceae, whereas Sclerotinia sclerotiorum and Botrytis cinerea are cosmopolitan broad host-range plant pathogens, Sclerotinia borealis has a psychrophilic lifestyle with a low optimal growth temperature, a narrow host range and geographic distribution. To spread successfully, S. borealis must synthesize proteins adapted to function in its specific environment. The search for signatures of adaptation to S. borealis lifestyle may therefore help revealing proteins critical for colonization of the environment by Sclerotiniaceae fungi. Here, we analyzed amino acids usage and intrinsic protein disorder in alignments of groups of orthologous proteins from the three Sclerotiniaceae species. We found that enrichment in Thr, depletion in Glu and Lys, and low disorder frequency in hot loops are significantly associated with S. borealis proteins. We designed an index to report bias in these properties and found that high index proteins were enriched among secreted proteins in the three Sclerotiniaceae fungi. High index proteins were also enriched in function associated with plant colonization in S. borealis, and in in planta-induced genes in S. sclerotiorum. We highlight a novel putative antifreeze protein and a novel putative lytic polysaccharide monooxygenase identified through our pipeline as candidate proteins involved in colonization of the environment. Our findings suggest that similar protein signatures associate with S. borealis lifestyle and with secretion in the Sclerotiniaceae. These signatures may be useful for identifying proteins of interest as targets for the management of plant diseases.
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Affiliation(s)
- Thomas Badet
- Laboratoire des Interactions Plantes-Microorganismes, Institut National de la Recherche Agronomique, UMR441Castanet-Tolosan, France
- Laboratoire des Interactions Plantes-Microorganismes, Centre National de la Recherche Scientifique, UMR2594Castanet-Tolosan, France
| | - Rémi Peyraud
- Laboratoire des Interactions Plantes-Microorganismes, Institut National de la Recherche Agronomique, UMR441Castanet-Tolosan, France
- Laboratoire des Interactions Plantes-Microorganismes, Centre National de la Recherche Scientifique, UMR2594Castanet-Tolosan, France
| | - Sylvain Raffaele
- Laboratoire des Interactions Plantes-Microorganismes, Institut National de la Recherche Agronomique, UMR441Castanet-Tolosan, France
- Laboratoire des Interactions Plantes-Microorganismes, Centre National de la Recherche Scientifique, UMR2594Castanet-Tolosan, France
- *Correspondence: Sylvain Raffaele, Laboratoire des Interactions Plante Micro-organismes, 24 Chemin de Borde Rouge – Auzeville, 31326 Castanet Tolosan, France
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Lam HN, Chakravarthy S, Wei HL, BuiNguyen H, Stodghill PV, Collmer A, Swingle BM, Cartinhour SW. Global analysis of the HrpL regulon in the plant pathogen Pseudomonas syringae pv. tomato DC3000 reveals new regulon members with diverse functions. PLoS One 2014; 9:e106115. [PMID: 25170934 PMCID: PMC4149516 DOI: 10.1371/journal.pone.0106115] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 07/28/2014] [Indexed: 11/18/2022] Open
Abstract
The type III secretion system (T3SS) is required for virulence in the gram-negative plant pathogen Pseudomonas syringae pv. tomato DC3000. The alternative sigma factor HrpL directly regulates expression of T3SS genes via a promoter sequence, often designated as the "hrp promoter." Although the HrpL regulon has been extensively investigated in DC3000, it is not known whether additional regulon members remain to be found. To systematically search for HrpL-regulated genes, we used chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-Seq) and bulk mRNA sequencing (RNA-Seq) to identify HrpL-binding sites and likely hrp promoters. The analysis recovered 73 sites of interest, including 20 sites that represent new hrp promoters. The new promoters lie upstream of a diverse set of genes encoding potential regulators, enzymes and hypothetical proteins. PSPTO_5633 is the only new HrpL regulon member that is potentially an effector and is now designated HopBM1. Deletions in several other new regulon members, including PSPTO_5633, PSPTO_0371, PSPTO_2130, PSPTO_2691, PSPTO_2696, PSPTO_3331, and PSPTO_5240, in either DC3000 or ΔhopQ1-1 backgrounds, do not affect the hypersensitive response or in planta growth of the resulting strains. Many new HrpL regulon members appear to be unrelated to the T3SS, and orthologs for some of these can be identified in numerous non-pathogenic bacteria. With the identification of 20 new hrp promoters, the list of HrpL regulon members is approaching saturation and most likely includes all DC3000 effectors.
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Affiliation(s)
- Hanh N. Lam
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Suma Chakravarthy
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Hai-Lei Wei
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - HoangChuong BuiNguyen
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Paul V. Stodghill
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
- United States Department of Agriculture-Agricultural Research Service, Ithaca, New York, United States of America
| | - Alan Collmer
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Bryan M. Swingle
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
- United States Department of Agriculture-Agricultural Research Service, Ithaca, New York, United States of America
| | - Samuel W. Cartinhour
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
- United States Department of Agriculture-Agricultural Research Service, Ithaca, New York, United States of America
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Wei HL, Chakravarthy S, Worley JN, Collmer A. Consequences of flagellin export through the type III secretion system of Pseudomonas syringae reveal a major difference in the innate immune systems of mammals and the model plant Nicotiana benthamiana. Cell Microbiol 2013; 15:601-18. [PMID: 23107228 DOI: 10.1111/cmi.12059] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 09/28/2012] [Accepted: 10/16/2012] [Indexed: 02/02/2023]
Abstract
Bacterial flagellin is perceived as a microbe (or pathogen)-associated molecular pattern (MAMP or PAMP) by the extracellular pattern recognition receptors, FLS2 and TLR5, of plants and mammals respectively. Flagellin accidently translocated into mammalian cells by pathogen type III secretion systems (T3SSs) is recognized by nucleotide-binding leucine-rich repeat receptor NLRC4 as a pattern of pathogenesis and induces a death-associated immune response. The non-pathogen Pseudomonas fluorescens Pf0-1, expressing a Pseudomonas syringae T3SS, and the plant pathogen P. syringae pv. tomato DC3000 were used to seek evidence of an analogous cytoplasmic recognition system for flagellin in the model plant Nicotiana benthamiana. Flagellin (FliC) was secreted in culture and translocated into plant cells by the T3SS expressed in Pf0-1 and DC3000 and in their ΔflgGHI flagellar pathway mutants. ΔfliC and ΔflgGHI mutants of Pf0-1 and DC3000 were strongly reduced in elicitation of reactive oxygen species production and in immunity induction as indicated by the ability of challenge bacteria inoculated 6 h later to translocate a type III effector-reporter and to elicit effector-triggered cell death. Agrobacterium-mediated transient expression in N. benthamiana of FliC with or without a eukaryotic export signal peptide, coupled with virus-induced gene silencing of FLS2, revealed no immune response that was not FLS2 dependent. Transiently expressed FliC from DC3000 and Pectobacterium carotovorum did notinduce cell death in N. benthamiana, tobacco or tomato leaves. Flagellin is the major Pseudomonas MAMP perceived by N. benthamiana, and although flagellin secretion through the plant cell wall by the T3SS may partially contribute to FLS2-dependent immunity, flagellin in the cytosol does not elicit immune-associated cell death. We postulate that a death response to translocated MAMPs would produce vulnerability to the many necrotrophic pathogens of plants, such as P. carotovorum, which differ from P. syringae and other (hemi)biotrophic pathogens in benefitting from death-associated immune responses.
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Affiliation(s)
- Hai-Lei Wei
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY, 14853, USA
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Dong X, Zhang YJ, Zhang Z. Using weakly conserved motifs hidden in secretion signals to identify type-III effectors from bacterial pathogen genomes. PLoS One 2013; 8:e56632. [PMID: 23437191 PMCID: PMC3577856 DOI: 10.1371/journal.pone.0056632] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 01/11/2013] [Indexed: 11/25/2022] Open
Abstract
Background As one of the most important virulence factor types in gram-negative pathogenic bacteria, type-III effectors (TTEs) play a crucial role in pathogen-host interactions by directly influencing immune signaling pathways within host cells. Based on the hypothesis that type-III secretion signals may be comprised of some weakly conserved sequence motifs, here we used profile-based amino acid pair information to develop an accurate TTE predictor. Results For a TTE or non-TTE, we first used a hidden Markov model-based sequence searching method (i.e., HHblits) to detect its weakly homologous sequences and extracted the profile-based k-spaced amino acid pair composition (HH-CKSAAP) from the N-terminal sequences. In the next step, the feature vector HH-CKSAAP was used to train a linear support vector machine model, which we designate as BEAN (Bacterial Effector ANalyzer). We compared our method with four existing TTE predictors through an independent test set, and our method revealed improved performance. Furthermore, we listed the most predictive amino acid pairs according to their weights in the established classification model. Evolutionary analysis shows that predictive amino acid pairs tend to be more conserved. Some predictive amino acid pairs also show significantly different position distributions between TTEs and non-TTEs. These analyses confirmed that some weakly conserved sequence motifs may play important roles in type-III secretion signals. Finally, we also used BEAN to scan one plant pathogen genome and showed that BEAN can be used for genome-wide TTE identification. The webserver and stand-alone version of BEAN are available at http://protein.cau.edu.cn:8080/bean/.
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Affiliation(s)
- Xiaobao Dong
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Yong-Jun Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ziding Zhang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
- * E-mail:
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