1
|
Achi SC, Karimilangi S, Lie D, Sayed IM, Das S. The WxxxE proteins in microbial pathogenesis. Crit Rev Microbiol 2023; 49:197-213. [PMID: 35287539 PMCID: PMC9737147 DOI: 10.1080/1040841x.2022.2046546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 02/10/2022] [Accepted: 02/19/2022] [Indexed: 12/14/2022]
Abstract
Effector proteins secreted by pathogens modulate various host cellular processes and help in bacterial pathogenesis. Some of these proteins, injected by enteric pathogens via Type Three Secretion System (T3SS) were grouped together based on a conserved signature motif (WxxxE) present in them. The presence of WxxxE motif is not limited to effectors released by enteric pathogens or the T3SS but has been detected in non-enteric pathogens, plant pathogens and in association with Type II and Type IV secretion systems. WxxxE effectors are involved in actin organization, inflammation regulation, vacuole or tubule formation, endolysosomal signalling regulation, tight junction disruption, and apoptosis. The WxxxE sequence has also been identified in TIR [Toll/interleukin-1 (IL-1) receptor] domains of bacteria and host. In the present review, we have focussed on the established and predicted functions of WxxxE effectors secreted by several pathogens, including enteric, non-enteric, and plant pathogens.
Collapse
Affiliation(s)
| | - Sareh Karimilangi
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Dominique Lie
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Ibrahim M. Sayed
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Soumita Das
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| |
Collapse
|
2
|
Bundalovic-Torma C, Lonjon F, Desveaux D, Guttman DS. Diversity, Evolution, and Function of Pseudomonas syringae Effectoromes. ANNUAL REVIEW OF PHYTOPATHOLOGY 2022; 60:211-236. [PMID: 35537470 DOI: 10.1146/annurev-phyto-021621-121935] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Pseudomonas syringae is an evolutionarily diverse bacterial species complex and a preeminent model for the study of plant-pathogen interactions due in part to its remarkably broad host range. A critical feature of P. syringae virulence is the employment of suites of type III secreted effector (T3SE) proteins, which vary widely in composition and function. These effectors act on a variety of plant intracellular targets to promote pathogenesis but can also be avirulence factors when detected by host immune complexes. In this review, we survey the phylogenetic diversity (PD) of the P. syringae effectorome, comprising 70 distinct T3SE families identified to date, and highlight how avoidance of host immune detection has shaped effectorome diversity through functional redundancy, diversification, and horizontal transfer. We present emerging avenues for research and novel insights that can be gained via future investigations of plant-pathogen interactions through the fusion of large-scale interaction screens and phylogenomic approaches.
Collapse
Affiliation(s)
| | - Fabien Lonjon
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada; ,
| | - Darrell Desveaux
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada; ,
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, Ontario, Canada
| | - David S Guttman
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada; ,
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
3
|
Dynamic nutrient acquisition from a hydrated apoplast supports biotrophic proliferation of a bacterial pathogen of maize. Cell Host Microbe 2022; 30:502-517.e4. [PMID: 35421350 DOI: 10.1016/j.chom.2022.03.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 02/09/2022] [Accepted: 03/10/2022] [Indexed: 11/24/2022]
Abstract
Plant pathogens perturb their hosts to create environments suitable for their proliferation, including the suppression of immunity and promotion of water and nutrient availability. Although necrotrophs obtain water and nutrients by disrupting host-cell integrity, it is unknown whether hemibiotrophs, such as the bacterial pathogen Pantoea stewartii subsp. stewartii (Pnss), actively liberate water and nutrients during the early, biotrophic phase of infection. Here, we show that water and metabolite accumulation in the apoplast of Pnss-infected maize leaves precedes the disruption of host-cell integrity. Nutrient acquisition during this biotrophic phase is a dynamic process; the partitioning of metabolites into the apoplast rate limiting for their assimilation by proliferating Pnss cells. The formation of a hydrated and nutritive apoplast is driven by an AvrE-family type III effector, WtsE. Given the broad distribution of AvrE-family effectors, this work highlights the importance of actively acquiring water and nutrients for the proliferation of phytopathogenic bacteria during biotrophy.
Collapse
|
4
|
Sayed IM, Ibeawuchi SR, Lie D, Anandachar MS, Pranadinata R, Raffatellu M, Das S. The interaction of enteric bacterial effectors with the host engulfment pathway control innate immune responses. Gut Microbes 2022; 13:1991776. [PMID: 34719317 PMCID: PMC8565811 DOI: 10.1080/19490976.2021.1991776] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Host engulfment protein ELMO1 generates intestinal inflammation following internalization of enteric bacteria. In Shigella, bacterial effector IpgB1 interacts with ELMO1 and promotes bacterial invasion. IpgB1 belongs to the WxxxE effector family, a motif found in several effectors of enteric pathogens. Here, we have studied the role of WxxxE effectors, with emphasis on Salmonella SifA and whether it interacts with ELMO1 to regulate inflammation. In-silico-analysis of WxxxE effectors was performed using BLAST search and Clustal W program. The interaction of ELMO1 with SifA was assessed by GST pulldown assay and co-immunoprecipitation. ELMO1 knockout mice, and ELMO1-depleted murine macrophage J774 cell lines were challenged with WT and SifA mutant Salmonella. Bacterial effectors containing the WxxxE motif were transfected in WT and ELMO1-depleted J774 cells to assess the inflammatory cytokines. ELMO1 generates differential pro-inflammatory cytokines between pathogenic and nonpathogenic bacteria. WxxxE motif is present in pathogens and in the TIR domain of host proteins. The C-terminal part of ELMO1 interacts with SifA where WxxxE motif is important for interaction. ELMO1-SifA interaction affects bacterial colonization, dissemination, and inflammatory cytokines in vivo. Moreover, ELMO1-SifA interaction increases TNF-α and IL-6 production from the macrophage cell line and is associated with enhanced Rac1 activity. ELMO1 also interacts with WxxxE effectors IpgB1, IpgB2, and Map and induces inflammation after challenge with microbes or microbial ligands. ELMO1 generates a differential response through interaction with the WxxxE motif, which is absent in commensals. ELMO1-WxxxE interaction plays a role in bacterial pathogenesis and induction of inflammatory response.
Collapse
Affiliation(s)
- Ibrahim M Sayed
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | | | - Dominique Lie
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | | | - Rama Pranadinata
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Manuela Raffatellu
- Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California San Diego, LA Jolla, CA, USA,Center for Mucosal Immunology, Chiba University-UC San Diego, La Jolla, CAUSA
| | - Soumita Das
- Department of Pathology, University of California San Diego, La Jolla, CA, USA,CONTACT Soumita Das Department of Pathology, University of California, San Diego, 9500 Gilman Drive, Mc 0644, George Palade Laboratory, Office Rm 256, San Diego, Ca, 92093-0644, USA
| |
Collapse
|
5
|
Huong DDT, Rajalingam N, Lee YH. Characterization of Virulence Function of Pseudomonas cichorii Avirulence Protein E1 (AvrE1) during Host Plant Infection. THE PLANT PATHOLOGY JOURNAL 2021; 37:494-501. [PMID: 34847636 PMCID: PMC8632607 DOI: 10.5423/ppj.nt.07.2021.0108] [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: 07/08/2021] [Revised: 08/17/2021] [Accepted: 08/29/2021] [Indexed: 06/13/2023]
Abstract
Pseudomonas cichorii secretes effectors that suppress defense mechanisms in host plants. However, the function of these effectors, including avirulence protein E1 (AvrE1), in the pathogenicity of P. cichorii, remains unexplored. In this study, to investigate the function of avrE1 in P. cichorii JBC1 (PcJBC1), we created an avrE1-deficient mutant (JBC1ΔavrE1) using CRISPR/Cas9. The disease severity caused by JBC1ΔavrE1 in tomato plants significantly decreased by reducing water soaking during early infection stage, as evidenced by the electrolyte leakage in infected leaves. The disease symptoms caused by JBC1ΔavrE1 in the cabbage midrib were light-brown spots compared to the dark-colored ones caused by PcJBC1, which indicates the role of AvrE1 in cell lysis. The avrE1-deficient mutant failed to elicit cell death in non-host tobacco plants. Disease severity and cell death caused by JBC1ΔavrE1 in host and non-host plants were restored through heterologous complementation with avrE1 from Pseudomonas syringae pv. tomato DC3000 (PstDC3000). Overall, our results indicate that avrE1 contributes to cell death during early infection, which consequently increases disease development in host plants. The roles of PcJBC1 AvrE1 in host cells remain to be elucidated.
Collapse
Affiliation(s)
| | | | - Yong Hoon Lee
- Division of Biotechnology, Jeonbuk National University, Iksan 54596, Korea
- Advanced Institute of Environment and Bioscience, Plant Medical Research Center, and Institute of Bio-industry, Jeonbuk National University, Iksan 54596, Korea
| |
Collapse
|
6
|
Yuan X, Hulin MT, Sundin GW. Effectors, chaperones, and harpins of the Type III secretion system in the fire blight pathogen Erwinia amylovora: a review. JOURNAL OF PLANT PATHOLOGY 2021; 103:25-39. [PMID: 0 DOI: 10.1007/s42161-020-00623-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 07/23/2020] [Indexed: 05/20/2023]
|
7
|
Schreiber KJ, Chau-Ly IJ, Lewis JD. What the Wild Things Do: Mechanisms of Plant Host Manipulation by Bacterial Type III-Secreted Effector Proteins. Microorganisms 2021; 9:1029. [PMID: 34064647 PMCID: PMC8150971 DOI: 10.3390/microorganisms9051029] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 01/05/2023] Open
Abstract
Phytopathogenic bacteria possess an arsenal of effector proteins that enable them to subvert host recognition and manipulate the host to promote pathogen fitness. The type III secretion system (T3SS) delivers type III-secreted effector proteins (T3SEs) from bacterial pathogens such as Pseudomonas syringae, Ralstonia solanacearum, and various Xanthomonas species. These T3SEs interact with and modify a range of intracellular host targets to alter their activity and thereby attenuate host immune signaling. Pathogens have evolved T3SEs with diverse biochemical activities, which can be difficult to predict in the absence of structural data. Interestingly, several T3SEs are activated following injection into the host cell. Here, we review T3SEs with documented enzymatic activities, as well as T3SEs that facilitate virulence-promoting processes either indirectly or through non-enzymatic mechanisms. We discuss the mechanisms by which T3SEs are activated in the cell, as well as how T3SEs modify host targets to promote virulence or trigger immunity. These mechanisms may suggest common enzymatic activities and convergent targets that could be manipulated to protect crop plants from infection.
Collapse
Affiliation(s)
- Karl J. Schreiber
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94710, USA; (K.J.S.); (I.J.C.-L.)
| | - Ilea J. Chau-Ly
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94710, USA; (K.J.S.); (I.J.C.-L.)
| | - Jennifer D. Lewis
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94710, USA; (K.J.S.); (I.J.C.-L.)
- Plant Gene Expression Center, United States Department of Agriculture, University of California, Berkeley, CA 94710, USA
| |
Collapse
|
8
|
Laflamme B, Dillon MM, Martel A, Almeida RND, Desveaux D, Guttman DS. The pan-genome effector-triggered immunity landscape of a host-pathogen interaction. Science 2020; 367:763-768. [PMID: 32054757 DOI: 10.1126/science.aax4079] [Citation(s) in RCA: 111] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 10/18/2019] [Accepted: 01/17/2020] [Indexed: 12/24/2022]
Abstract
Effector-triggered immunity (ETI), induced by host immune receptors in response to microbial effectors, protects plants against virulent pathogens. However, a systematic study of ETI prevalence against species-wide pathogen diversity is lacking. We constructed the Pseudomonas syringae Type III Effector Compendium (PsyTEC) to reduce the pan-genome complexity of 5127 unique effector proteins, distributed among 70 families from 494 strains, to 529 representative alleles. We screened PsyTEC on the model plant Arabidopsis thaliana and identified 59 ETI-eliciting alleles (11.2%) from 19 families (27.1%), with orthologs distributed among 96.8% of P. syringae strains. We also identified two previously undescribed host immune receptors, including CAR1, which recognizes the conserved effectors AvrE and HopAA1, and found that 94.7% of strains harbor alleles predicted to be recognized by either CAR1 or ZAR1.
Collapse
Affiliation(s)
- Bradley Laflamme
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Marcus M Dillon
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Alexandre Martel
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Renan N D Almeida
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Darrell Desveaux
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada.
| | - David S Guttman
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada. .,Center for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON M5S 3B2, Canada
| |
Collapse
|
9
|
Doblas-Ibáñez P, Deng K, Vasquez MF, Giese L, Cobine PA, Kolkman JM, King H, Jamann TM, Balint-Kurti P, De La Fuente L, Nelson RJ, Mackey D, Smith LG. Dominant, Heritable Resistance to Stewart's Wilt in Maize Is Associated with an Enhanced Vascular Defense Response to Infection with Pantoea stewartii. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:1581-1597. [PMID: 31657672 DOI: 10.1094/mpmi-05-19-0129-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Vascular wilt bacteria such as Pantoea stewartii, the causal agent of Stewart's bacterial wilt of maize (SW), are destructive pathogens that are difficult to control. These bacteria colonize the xylem, where they form biofilms that block sap flow leading to characteristic wilting symptoms. Heritable forms of SW resistance exist and are used in maize breeding programs but the underlying genes and mechanisms are mostly unknown. Here, we show that seedlings of maize inbred lines with pan1 mutations are highly resistant to SW. However, current evidence suggests that other genes introgressed along with pan1 are responsible for resistance. Genomic analyses of pan1 lines were used to identify candidate resistance genes. In-depth comparison of P. stewartii interaction with susceptible and resistant maize lines revealed an enhanced vascular defense response in pan1 lines characterized by accumulation of electron-dense materials in xylem conduits visible by electron microscopy. We propose that this vascular defense response restricts P. stewartii spread through the vasculature, reducing both systemic bacterial colonization of the xylem network and consequent wilting. Though apparently unrelated to the resistance phenotype of pan1 lines, we also demonstrate that the effector WtsE is essential for P. stewartii xylem dissemination, show evidence for a nutritional immunity response to P. stewartii that alters xylem sap composition, and present the first analysis of maize transcriptional responses to P. stewartii infection.
Collapse
Affiliation(s)
- Paula Doblas-Ibáñez
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92093, U.S.A
| | - Kaiyue Deng
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92093, U.S.A
| | - Miguel F Vasquez
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92093, U.S.A
| | - Laura Giese
- Department of Horticulture and Crop Sciences, The Ohio State University, Columbus, OH 43210, U.S.A
| | - Paul A Cobine
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, U.S.A
| | - Judith M Kolkman
- School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
| | - Helen King
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92093, U.S.A
| | - Tiffany M Jamann
- Department of Crop Sciences, University of Illinois Urbana-Champaign, Urbana, IL 61801, U.S.A
| | - Peter Balint-Kurti
- United States Department of Agriculture-Agricultural Research Service, Plant Science Research Unit, Raleigh, NC 27695, U.S.A. and Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695, U.S.A
| | | | - Rebecca J Nelson
- School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
| | - David Mackey
- Department of Horticulture and Crop Sciences, The Ohio State University, Columbus, OH 43210, U.S.A
| | - Laurie G Smith
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92093, U.S.A
| |
Collapse
|
10
|
Stringlis IA, Zamioudis C, Berendsen RL, Bakker PAHM, Pieterse CMJ. Type III Secretion System of Beneficial Rhizobacteria Pseudomonas simiae WCS417 and Pseudomonas defensor WCS374. Front Microbiol 2019; 10:1631. [PMID: 31379783 PMCID: PMC6647874 DOI: 10.3389/fmicb.2019.01631] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 07/02/2019] [Indexed: 11/13/2022] Open
Abstract
Plants roots host myriads of microbes, some of which enhance the defense potential of plants by activating a broad-spectrum immune response in leaves, known as induced systemic resistance (ISR). Nevertheless, establishment of this mutualistic interaction requires active suppression of local root immune responses to allow successful colonization. To facilitate host colonization, phytopathogenic bacteria secrete immune-suppressive effectors into host cells via the type III secretion system (T3SS). Previously, we searched the genomes of the ISR-inducing rhizobacteria Pseudomonas simiae WCS417 and Pseudomonas defensor WCS374 for the presence of a T3SS and identified the components for a T3SS in the genomes of WCS417 and WCS374. By performing a phylogenetic and gene cluster alignment analysis we show that the T3SS of WCS417 and WCS374 are grouped in a clade that is enriched for beneficial rhizobacteria. We also found sequences of putative novel effectors in their genomes, which may facilitate future research on the role of T3SS effectors in plant-beneficial microbe interactions in the rhizosphere.
Collapse
Affiliation(s)
- Ioannis A Stringlis
- Plant-Microbe Interactions, Department of Biology, Science4Life, Utrecht University, Utrecht, Netherlands
| | - Christos Zamioudis
- Plant-Microbe Interactions, Department of Biology, Science4Life, Utrecht University, Utrecht, Netherlands
| | - Roeland L Berendsen
- Plant-Microbe Interactions, Department of Biology, Science4Life, Utrecht University, Utrecht, Netherlands
| | - Peter A H M Bakker
- Plant-Microbe Interactions, Department of Biology, Science4Life, Utrecht University, Utrecht, Netherlands
| | - Corné M J Pieterse
- Plant-Microbe Interactions, Department of Biology, Science4Life, Utrecht University, Utrecht, Netherlands
| |
Collapse
|
11
|
Zhang Z, Luo Z, Min W, Zhang L, Wu Y, Hu X. An anti-cancer WxxxE-containing azurin polypeptide inhibits Rac1-dependent STAT3 and ERK/GSK-3β signaling in breast cancer cells. Oncotarget 2018; 8:43091-43103. [PMID: 28549350 PMCID: PMC5522130 DOI: 10.18632/oncotarget.17759] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 03/28/2017] [Indexed: 12/15/2022] Open
Abstract
In our previous study, we characterized a mycoplasmal small GTPase-like polypeptide of 240 amino acids that possesses an N-terminal WVLGE sequence. The N-terminal WVLGE sequence promotes activation of Rac1 and subsequent host cancer cell proliferation. To investigate the function of the WxxxE motif in the interaction with Rac1 and host tumor progression, we synthesized a 35-amino acid WVLGE-containing polypeptide derived from a cell-penetrating peptide derived from the azurin protein. We verified that the WVLGE-containing polypeptide targeted MCF-7 cells rather than MCF-10A cells. However, the WVLGE-containing polypeptide inhibited activation of Rac1 and induced cellular phenotypes that resulted from inhibition of Rac1. In addition, the WVLGE-containing polypeptide down-regulated phosphorylation of the STAT3 and ERK/GSK-3β signaling pathways, and this effect was abolished by either stimulation or inhibition of Rac1 activity. We also found that the WVLGE-containing polypeptide has a Rac1-dependent potential to suppress breast cancer growth in vitro and in vivo. We suggest that by acting as a Rac1 inhibitor, this novel polypeptide may be useful for the treatment of breast cancer.
Collapse
Affiliation(s)
- Zhe Zhang
- Department of Breast and Thyroid Surgery, Division of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Zhiyong Luo
- Department of Breast and Thyroid Surgery, Division of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Wenpu Min
- The First People's Hospital of Jingzhou, Jingzhou, People's Republic of China
| | - Lin Zhang
- Department of Breast and Thyroid Surgery, Division of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Yaqun Wu
- Department of Breast and Thyroid Surgery, Division of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Xiaopeng Hu
- Department of Breast and Thyroid Surgery, Division of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| |
Collapse
|
12
|
Deb D, Mackey D, Opiyo SO, McDowell JM. Application of alignment-free bioinformatics methods to identify an oomycete protein with structural and functional similarity to the bacterial AvrE effector protein. PLoS One 2018; 13:e0195559. [PMID: 29641586 PMCID: PMC5895030 DOI: 10.1371/journal.pone.0195559] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Accepted: 03/23/2018] [Indexed: 11/23/2022] Open
Abstract
Diverse plant pathogens export effector proteins to reprogram host cells. One of the most challenging goals in the molecular plant-microbe field is to functionally characterize the complex repertoires of effectors secreted by these pathogens. For bacterial pathogens, the predominant class of effectors is delivered to host cells by Type III secretion. For oomycetes, the predominant class of effectors is defined by a signal peptide that mediates secretion from the oomycete and a conserved RxLR motif. Downy mildew pathogens and Phytophthora species maintain hundreds of candidate RxLR effector genes in their genomes. Although no primary sequence similarity is evident between bacterial Type III effectors (T3Es) and oomycete RXLR effectors, some bacterial and oomycete effectors have convergently evolved to target the same host proteins. Such effectors might have evolved domains that are functionally similar but sequence-unrelated. We reasoned that alignment-free bioinformatics approaches could be useful to identify structural similarities between bacterial and oomycete effectors. To test this approach, we used partial least squares regression, alignment-free bioinformatics methods to identify effector proteins from the genome of the oomycete Hyaloperonospora arabidopsidis that are similar to the well-studied AvrE1 effector from Pseudomonas syringae. This approach identified five RxLR proteins with putative structural similarity to AvrE1. We focused on one, HaRxL23, because it is an experimentally validated effector and it is conserved between distantly related oomycetes. Several experiments indicate that HaRxL23 is functionally similar to AvrE1, including the ability to partially rescue an AvrE1 loss-of-function mutant. This study provides an example of how an alignment-free bioinformatics approach can identify functionally similar effector proteins in the absence of primary sequence similarity. This approach could be useful to identify effectors that have convergently evolved regardless of whether the shared host target is known.
Collapse
Affiliation(s)
- Devdutta Deb
- Department of Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, Virginia, United States of America
| | - David Mackey
- Departments of Horticulture and Crop Science and Molecular Genetics, Ohio State University, Columbus, Ohio, United States of America
| | - Stephen O. Opiyo
- Molecular and Cellular Imaging Center-Columbus, Ohio Agricultural Research and Development Center, Ohio State University, Columbus, Ohio, United States of America
- * E-mail: (SOO); (JMM)
| | - John M. McDowell
- Department of Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail: (SOO); (JMM)
| |
Collapse
|
13
|
Wang GF, Balint-Kurti PJ. Maize Homologs of CCoAOMT and HCT, Two Key Enzymes in Lignin Biosynthesis, Form Complexes with the NLR Rp1 Protein to Modulate the Defense Response. PLANT PHYSIOLOGY 2016; 171:2166-77. [PMID: 27208251 PMCID: PMC4936554 DOI: 10.1104/pp.16.00224] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 05/08/2016] [Indexed: 05/20/2023]
Abstract
Disease resistance (R) genes encode nucleotide binding Leu-rich-repeat (NLR) proteins that confer resistance to specific pathogens. Upon pathogen recognition they trigger a defense response that usually includes a so-called hypersensitive response (HR), a rapid localized cell death at the site of pathogen infection. Intragenic recombination between two maize (Zea mays) NLRs, Rp1-D and Rp1-dp2, resulted in the formation of a hybrid NLR, Rp1-D21, which confers an autoactive HR in the absence of pathogen infection. From a previous quantitative trait loci and genome-wide association study, we identified genes encoding two key enzymes in lignin biosynthesis, hydroxycinnamoyltransferase (HCT) and caffeoyl CoA O-methyltransferase (CCoAOMT), adjacent to the nucleotide polymorphisms that were highly associated with variation in the severity of Rp1-D21-induced HR We have previously shown that the two maize HCT homologs suppress the HR conferred by Rp1-D21 in a heterologous system, very likely through physical interaction. Here, we show, similarly, that CCoAOMT2 suppresses the HR induced by either the full-length or by the N-terminal coiled-coil domain of Rp1-D21 also likely via physical interaction and that the metabolic activity of CCoAOMT2 is unlikely to be necessary for its role in suppressing HR. We also demonstrate that CCoAOMT2, HCTs, and Rp1 proteins can form in the same complexes. A model is derived to explain the roles of CCoAOMT and HCT in Rp1-mediated defense resistance.
Collapse
Affiliation(s)
- Guan-Feng Wang
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695 (G.-F.W., P.J.B.-K.)Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Sciences, Shandong University, Jinan, Shandong 250100, P.R. China (G.-F.W.); U.S. Department of Agriculture-Agricultural Research Service, Plant Science Research Unit, Raleigh, North Carolina 27695 (P.J.B.-K.)
| | - Peter J Balint-Kurti
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695 (G.-F.W., P.J.B.-K.)Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Sciences, Shandong University, Jinan, Shandong 250100, P.R. China (G.-F.W.); U.S. Department of Agriculture-Agricultural Research Service, Plant Science Research Unit, Raleigh, North Carolina 27695 (P.J.B.-K.)
| |
Collapse
|
14
|
Serrano I, Audran C, Rivas S. Chloroplasts at work during plant innate immunity. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3845-54. [PMID: 26994477 DOI: 10.1093/jxb/erw088] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The major role played by chloroplasts during light harvesting, energy production, redox homeostasis, and retrograde signalling processes has been extensively characterized. Beyond the obvious link between chloroplast functions in primary metabolism and as providers of photosynthesis-derived carbon sources and energy, a growing body of evidence supports a central role for chloroplasts as integrators of environmental signals and, more particularly, as key defence organelles. Here, we review the importance of these organelles as primary sites for the biosynthesis and transmission of pro-defence signals during plant immune responses. In addition, we highlight interorganellar communication as a crucial process for amplification of the immune response. Finally, molecular strategies used by microbes to manipulate, directly or indirectly, the production/function of defence-related signalling molecules and subvert chloroplast-based defences are also discussed.
Collapse
Affiliation(s)
- Irene Serrano
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Corinne Audran
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Susana Rivas
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| |
Collapse
|
15
|
Jin L, Ham JH, Hage R, Zhao W, Soto-Hernández J, Lee SY, Paek SM, Kim MG, Boone C, Coplin DL, Mackey D. Direct and Indirect Targeting of PP2A by Conserved Bacterial Type-III Effector Proteins. PLoS Pathog 2016; 12:e1005609. [PMID: 27191168 PMCID: PMC4871590 DOI: 10.1371/journal.ppat.1005609] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 04/12/2016] [Indexed: 11/19/2022] Open
Abstract
Bacterial AvrE-family Type-III effector proteins (T3Es) contribute significantly to the virulence of plant-pathogenic species of Pseudomonas, Pantoea, Ralstonia, Erwinia, Dickeya and Pectobacterium, with hosts ranging from monocots to dicots. However, the mode of action of AvrE-family T3Es remains enigmatic, due in large part to their toxicity when expressed in plant or yeast cells. To search for targets of WtsE, an AvrE-family T3E from the maize pathogen Pantoea stewartii subsp. stewartii, we employed a yeast-two-hybrid screen with non-lethal fragments of WtsE and a synthetic genetic array with full-length WtsE. Together these screens indicate that WtsE targets maize protein phosphatase 2A (PP2A) heterotrimeric enzyme complexes via direct interaction with B' regulatory subunits. AvrE1, another AvrE-family T3E from Pseudomonas syringae pv. tomato strain DC3000 (Pto DC3000), associates with specific PP2A B' subunit proteins from its susceptible host Arabidopsis that are homologous to the maize B' subunits shown to interact with WtsE. Additionally, AvrE1 was observed to associate with the WtsE-interacting maize proteins, indicating that PP2A B' subunits are likely conserved targets of AvrE-family T3Es. Notably, the ability of AvrE1 to promote bacterial growth and/or suppress callose deposition was compromised in Arabidopsis plants with mutations of PP2A genes. Also, chemical inhibition of PP2A activity blocked the virulence activity of both WtsE and AvrE1 in planta. The function of HopM1, a Pto DC3000 T3E that is functionally redundant to AvrE1, was also impaired in specific PP2A mutant lines, although no direct interaction with B' subunits was observed. These results indicate that sub-component specific PP2A complexes are targeted by bacterial T3Es, including direct targeting by members of the widely conserved AvrE-family.
Collapse
Affiliation(s)
- Lin Jin
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio, United States of America
| | - Jong Hyun Ham
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio, United States of America
- Department of Plant Pathology, The Ohio State University, Columbus, Ohio, United States of America
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, United States of America
| | - Rosemary Hage
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio, United States of America
| | - Wanying Zhao
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio, United States of America
| | - Jaricelis Soto-Hernández
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio, United States of America
| | - Sang Yeol Lee
- Division of Applied Life Science (BK21Plus), PMBBRC, Gyeongsang National University, Jinju daero, Jinju, Republic of Korea
| | - Seung-Mann Paek
- College of Pharmacy, Research Institute of Pharmaceutical Science, PMBBRC, Gyeongsang National University, Jinju daero, Jinju, Republic of Korea
| | - Min Gab Kim
- College of Pharmacy, Research Institute of Pharmaceutical Science, PMBBRC, Gyeongsang National University, Jinju daero, Jinju, Republic of Korea
| | - Charles Boone
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - David L. Coplin
- Department of Plant Pathology, The Ohio State University, Columbus, Ohio, United States of America
| | - David Mackey
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio, United States of America
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| |
Collapse
|
16
|
Popa C, Coll NS, Valls M, Sessa G. Yeast as a Heterologous Model System to Uncover Type III Effector Function. PLoS Pathog 2016; 12:e1005360. [PMID: 26914889 PMCID: PMC4767418 DOI: 10.1371/journal.ppat.1005360] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Type III effectors (T3E) are key virulence proteins that are injected by bacterial pathogens inside the cells of their host to subvert cellular processes and contribute to disease. The budding yeast Saccharomyces cerevisiae represents an important heterologous system for the functional characterisation of T3E proteins in a eukaryotic environment. Importantly, yeast contains eukaryotic processes with low redundancy and are devoid of immunity mechanisms that counteract T3Es and mask their function. Expression in yeast of effectors from both plant and animal pathogens that perturb conserved cellular processes often resulted in robust phenotypes that were exploited to elucidate effector functions, biochemical properties, and host targets. The genetic tractability of yeast and its amenability for high-throughput functional studies contributed to the success of this system that, in recent years, has been used to study over 100 effectors. Here, we provide a critical view on this body of work and describe advantages and limitations inherent to the use of yeast in T3E research. “Favourite” targets of T3Es in yeast are cytoskeleton components and small GTPases of the Rho family. We describe how mitogen-activated protein kinase (MAPK) signalling, vesicle trafficking, membrane structures, and programmed cell death are also often altered by T3Es in yeast and how this reflects their function in the natural host. We describe how effector structure–function studies and analysis of candidate targeted processes or pathways can be carried out in yeast. We critically analyse technologies that have been used in yeast to assign biochemical functions to T3Es, including transcriptomics and proteomics, as well as suppressor, gain-of-function, or synthetic lethality screens. We also describe how yeast can be used to select for molecules that block T3E function in search of new antibacterial drugs with medical applications. Finally, we provide our opinion on the limitations of S. cerevisiae as a model system and its most promising future applications.
Collapse
Affiliation(s)
- Crina Popa
- Genetics Department, Universitat de Barcelona, Barcelona, Catalonia, Spain
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Núria S. Coll
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Marc Valls
- Genetics Department, Universitat de Barcelona, Barcelona, Catalonia, Spain
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
- * E-mail: (GS); (MV)
| | - Guido Sessa
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv, Israel
- * E-mail: (GS); (MV)
| |
Collapse
|
17
|
Roper MC, Burbank LP, Williams K, Viravathana P, Tien HY, von Bodman S. A Large Repetitive RTX-Like Protein Mediates Water-Soaked Lesion Development, Leakage of Plant Cell Content and Host Colonization in the Pantoea stewartii subsp. stewartii Pathosystem. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:1374-1382. [PMID: 26284907 DOI: 10.1094/mpmi-05-15-0109-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Pantoea stewartii subsp. stewartii is the etiological agent of Stewart's wilt and is a serious bacterial pathogen affecting sweet corn. During the leaf blight phase, P. stewartii colonizes the leaf apoplast and causes a characteristic water-soaked lesion. The Hrp type III secretion system has been implicated in the water-soaking phenotype, and the goal of this study was to investigate other potential factors that contribute to the plant cellular disruption associated with these lesions. The P. stewartii genome contains a gene encoding a large repetitive RTX toxin, designated rtx2. RTX toxins comprise a large family of pore-forming proteins, which are widely distributed among gram-negative bacteria. These cytotoxins usually lyse their target host cells and cause significant tissue damage as a consequence. We hypothesized that this RTX-like toxin plays a role in the water-soaking phase of infection due to its predicted cytolytic properties. Based on the data reported here, we conclude that RTX2 contributes significantly to the development of water-soaked lesions and leakage of plant cellular contents and is an important pathogenicity factor for P. stewartii.
Collapse
Affiliation(s)
- M Caroline Roper
- 1 Department of Plant Pathology and Microbiology, University of California, Riverside, Riverside, CA 92521, U.S.A
| | - Lindsey P Burbank
- 1 Department of Plant Pathology and Microbiology, University of California, Riverside, Riverside, CA 92521, U.S.A
| | - Kayla Williams
- 1 Department of Plant Pathology and Microbiology, University of California, Riverside, Riverside, CA 92521, U.S.A
| | - Polrit Viravathana
- 1 Department of Plant Pathology and Microbiology, University of California, Riverside, Riverside, CA 92521, U.S.A
| | - Hsin-Yu Tien
- 3 Department of Plant Sciences, University of Connecticut, Storrs, CT 06238, U.S.A
| | - Susanne von Bodman
- 2 Division of Molecular and Cellular Biosciences, National Science Foundation, Arlington, VA 22230, U.S.A
| |
Collapse
|
18
|
Degrave A, Siamer S, Boureau T, Barny MA. The AvrE superfamily: ancestral type III effectors involved in suppression of pathogen-associated molecular pattern-triggered immunity. MOLECULAR PLANT PATHOLOGY 2015; 16:899-905. [PMID: 25640649 PMCID: PMC6638435 DOI: 10.1111/mpp.12237] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The AvrE superfamily of type III effectors (T3Es) is widespread among type III-dependent phytobacteria and plays a crucial role during bacterial pathogenesis. Members of the AvrE superfamily are vertically inherited core effectors, indicating an ancestral acquisition of these effectors in bacterial plant pathogens. AvrE-T3Es contribute significantly to virulence by suppressing pathogen-associated molecular pattern (PAMP)-triggered immunity. They inhibit salicylic acid-mediated plant defences, interfere with vesicular trafficking and promote bacterial growth in planta. AvrE-T3Es elicit cell death in both host and non-host plants independent of any known plant resistance protein, suggesting an original interaction with the plant immune system. Recent studies in yeast have indicated that they activate protein phosphatase 2A and inhibit serine palmitoyl transferase, the first enzyme of the sphingolipid biosynthesis pathway. In this review, we describe the current picture that has emerged from studies of the different members of this fascinating large family.
Collapse
Affiliation(s)
- Alexandre Degrave
- AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences (IRHS), 49045, Angers, France
- UMR1345, IRHS, Institut National de la Recherche Agronomique (INRA), 49071, Beaucouzé, France
| | - Sabrina Siamer
- Focal Area Infection Biology, Biozentrum, University of Basel, CH-4056, Basel, Switzerland
| | - Tristan Boureau
- UMR1345, IRHS, Institut National de la Recherche Agronomique (INRA), 49071, Beaucouzé, France
- UMR1345, IRHS, Université d'Angers, SFR 4207 QUASAV, PRES l'UNAM, 49045, Angers, France
| | - Marie-Anne Barny
- UMR1392, INRA, Institut d'Ecologie et des Sciences de l'Environnement, Université Pierre et Marie Curie (UPMC), Bât á 7ème Etage Case 237, 7 Quai St.-Bernard, 75252, Paris, France
| |
Collapse
|
19
|
Xin XF, Nomura K, Ding X, Chen X, Wang K, Aung K, Uribe F, Rosa B, Yao J, Chen J, He SY. Pseudomonas syringae Effector Avirulence Protein E Localizes to the Host Plasma Membrane and Down-Regulates the Expression of the NONRACE-SPECIFIC DISEASE RESISTANCE1/HARPIN-INDUCED1-LIKE13 Gene Required for Antibacterial Immunity in Arabidopsis. PLANT PHYSIOLOGY 2015; 169. [PMID: 26206852 PMCID: PMC4577396 DOI: 10.1104/pp.15.00547] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Many bacterial pathogens of plants and animals deliver effector proteins into host cells to promote infection. Elucidation of how pathogen effector proteins function not only is critical for understanding bacterial pathogenesis but also provides a useful tool in discovering the functions of host genes. In this study, we characterized the Pseudomonas syringae pv tomato DC3000 effector protein Avirulence Protein E (AvrE), the founding member of a widely distributed, yet functionally enigmatic, bacterial effector family. We show that AvrE is localized in the plasma membrane (PM) and PM-associated vesicle-like structures in the plant cell. AvrE contains two physically interacting domains, and the amino-terminal portion contains a PM-localization signal. Genome-wide microarray analysis indicates that AvrE, as well as the functionally redundant effector Hypersensitive response and pathogenicity-dependent Outer Protein M1, down-regulates the expression of the NONRACE-SPECIFIC DISEASE RESISTANCE1/HARPIN-INDUCED1-LIKE13 (NHL13) gene in Arabidopsis (Arabidopsis thaliana). Mutational analysis shows that NHL13 is required for plant immunity, as the nhl13 mutant plant displayed enhanced disease susceptibility. Our results defined the action site of one of the most important bacterial virulence proteins in plants and the antibacterial immunity function of the NHL13 gene.
Collapse
Affiliation(s)
- Xiu-Fang Xin
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Kinya Nomura
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Xinhua Ding
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Xujun Chen
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Kun Wang
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Kyaw Aung
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Francisco Uribe
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Bruce Rosa
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Jian Yao
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Jin Chen
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Sheng Yang He
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| |
Collapse
|
20
|
Asselin JAE, Lin J, Perez-Quintero AL, Gentzel I, Majerczak D, Opiyo SO, Zhao W, Paek SM, Kim MG, Coplin DL, Blakeslee JJ, Mackey D. Perturbation of maize phenylpropanoid metabolism by an AvrE family type III effector from Pantoea stewartii. PLANT PHYSIOLOGY 2015; 167:1117-35. [PMID: 25635112 PMCID: PMC4348765 DOI: 10.1104/pp.114.253120] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 01/24/2015] [Indexed: 05/20/2023]
Abstract
AvrE family type III effector proteins share the ability to suppress host defenses, induce disease-associated cell death, and promote bacterial growth. However, despite widespread contributions to numerous bacterial diseases in agriculturally important plants, the mode of action of these effectors remains largely unknown. WtsE is an AvrE family member required for the ability of Pantoea stewartii ssp. stewartii (Pnss) to proliferate efficiently and cause wilt and leaf blight symptoms in maize (Zea mays) plants. Notably, when WtsE is delivered by a heterologous system into the leaf cells of susceptible maize seedlings, it alone produces water-soaked disease symptoms reminiscent of those produced by Pnss. Thus, WtsE is a pathogenicity and virulence factor in maize, and an Escherichia coli heterologous delivery system can be used to study the activity of WtsE in isolation from other factors produced by Pnss. Transcriptional profiling of maize revealed the effects of WtsE, including induction of genes involved in secondary metabolism and suppression of genes involved in photosynthesis. Targeted metabolite quantification revealed that WtsE perturbs maize metabolism, including the induction of coumaroyl tyramine. The ability of mutant WtsE derivatives to elicit transcriptional and metabolic changes in susceptible maize seedlings correlated with their ability to promote disease. Furthermore, chemical inhibitors that block metabolic flux into the phenylpropanoid pathways targeted by WtsE also disrupted the pathogenicity and virulence activity of WtsE. While numerous metabolites produced downstream of the shikimate pathway are known to promote plant defense, our results indicate that misregulated induction of phenylpropanoid metabolism also can be used to promote pathogen virulence.
Collapse
Affiliation(s)
- Jo Ann E Asselin
- Department of Horticulture and Crop Science (J.E.A., J.L., A.L.P.-Q., Do.M., W.Z., J.J.B., Da.M.), Molecular and Cellular Imaging Center-Columbus, Ohio Agricultural Research and Development Center (J.L., S.O.O., J.J.B.), Translational Plant Sciences Graduate Program (I.G.), Center for Applied Plant Sciences (I.G., Da.M.), Department of Plant Pathology (D.L.C.), and Department of Molecular Genetics (Da.M.), Ohio State University, Columbus, Ohio 43210; andCollege of Pharmacy, Research Institute of Pharmaceutical Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-751, Republic of Korea (S.-M.P., M.G.K.)
| | - Jinshan Lin
- Department of Horticulture and Crop Science (J.E.A., J.L., A.L.P.-Q., Do.M., W.Z., J.J.B., Da.M.), Molecular and Cellular Imaging Center-Columbus, Ohio Agricultural Research and Development Center (J.L., S.O.O., J.J.B.), Translational Plant Sciences Graduate Program (I.G.), Center for Applied Plant Sciences (I.G., Da.M.), Department of Plant Pathology (D.L.C.), and Department of Molecular Genetics (Da.M.), Ohio State University, Columbus, Ohio 43210; andCollege of Pharmacy, Research Institute of Pharmaceutical Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-751, Republic of Korea (S.-M.P., M.G.K.)
| | - Alvaro L Perez-Quintero
- Department of Horticulture and Crop Science (J.E.A., J.L., A.L.P.-Q., Do.M., W.Z., J.J.B., Da.M.), Molecular and Cellular Imaging Center-Columbus, Ohio Agricultural Research and Development Center (J.L., S.O.O., J.J.B.), Translational Plant Sciences Graduate Program (I.G.), Center for Applied Plant Sciences (I.G., Da.M.), Department of Plant Pathology (D.L.C.), and Department of Molecular Genetics (Da.M.), Ohio State University, Columbus, Ohio 43210; andCollege of Pharmacy, Research Institute of Pharmaceutical Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-751, Republic of Korea (S.-M.P., M.G.K.)
| | - Irene Gentzel
- Department of Horticulture and Crop Science (J.E.A., J.L., A.L.P.-Q., Do.M., W.Z., J.J.B., Da.M.), Molecular and Cellular Imaging Center-Columbus, Ohio Agricultural Research and Development Center (J.L., S.O.O., J.J.B.), Translational Plant Sciences Graduate Program (I.G.), Center for Applied Plant Sciences (I.G., Da.M.), Department of Plant Pathology (D.L.C.), and Department of Molecular Genetics (Da.M.), Ohio State University, Columbus, Ohio 43210; andCollege of Pharmacy, Research Institute of Pharmaceutical Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-751, Republic of Korea (S.-M.P., M.G.K.)
| | - Doris Majerczak
- Department of Horticulture and Crop Science (J.E.A., J.L., A.L.P.-Q., Do.M., W.Z., J.J.B., Da.M.), Molecular and Cellular Imaging Center-Columbus, Ohio Agricultural Research and Development Center (J.L., S.O.O., J.J.B.), Translational Plant Sciences Graduate Program (I.G.), Center for Applied Plant Sciences (I.G., Da.M.), Department of Plant Pathology (D.L.C.), and Department of Molecular Genetics (Da.M.), Ohio State University, Columbus, Ohio 43210; andCollege of Pharmacy, Research Institute of Pharmaceutical Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-751, Republic of Korea (S.-M.P., M.G.K.)
| | - Stephen O Opiyo
- Department of Horticulture and Crop Science (J.E.A., J.L., A.L.P.-Q., Do.M., W.Z., J.J.B., Da.M.), Molecular and Cellular Imaging Center-Columbus, Ohio Agricultural Research and Development Center (J.L., S.O.O., J.J.B.), Translational Plant Sciences Graduate Program (I.G.), Center for Applied Plant Sciences (I.G., Da.M.), Department of Plant Pathology (D.L.C.), and Department of Molecular Genetics (Da.M.), Ohio State University, Columbus, Ohio 43210; andCollege of Pharmacy, Research Institute of Pharmaceutical Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-751, Republic of Korea (S.-M.P., M.G.K.)
| | - Wanying Zhao
- Department of Horticulture and Crop Science (J.E.A., J.L., A.L.P.-Q., Do.M., W.Z., J.J.B., Da.M.), Molecular and Cellular Imaging Center-Columbus, Ohio Agricultural Research and Development Center (J.L., S.O.O., J.J.B.), Translational Plant Sciences Graduate Program (I.G.), Center for Applied Plant Sciences (I.G., Da.M.), Department of Plant Pathology (D.L.C.), and Department of Molecular Genetics (Da.M.), Ohio State University, Columbus, Ohio 43210; andCollege of Pharmacy, Research Institute of Pharmaceutical Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-751, Republic of Korea (S.-M.P., M.G.K.)
| | - Seung-Mann Paek
- Department of Horticulture and Crop Science (J.E.A., J.L., A.L.P.-Q., Do.M., W.Z., J.J.B., Da.M.), Molecular and Cellular Imaging Center-Columbus, Ohio Agricultural Research and Development Center (J.L., S.O.O., J.J.B.), Translational Plant Sciences Graduate Program (I.G.), Center for Applied Plant Sciences (I.G., Da.M.), Department of Plant Pathology (D.L.C.), and Department of Molecular Genetics (Da.M.), Ohio State University, Columbus, Ohio 43210; andCollege of Pharmacy, Research Institute of Pharmaceutical Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-751, Republic of Korea (S.-M.P., M.G.K.)
| | - Min Gab Kim
- Department of Horticulture and Crop Science (J.E.A., J.L., A.L.P.-Q., Do.M., W.Z., J.J.B., Da.M.), Molecular and Cellular Imaging Center-Columbus, Ohio Agricultural Research and Development Center (J.L., S.O.O., J.J.B.), Translational Plant Sciences Graduate Program (I.G.), Center for Applied Plant Sciences (I.G., Da.M.), Department of Plant Pathology (D.L.C.), and Department of Molecular Genetics (Da.M.), Ohio State University, Columbus, Ohio 43210; andCollege of Pharmacy, Research Institute of Pharmaceutical Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-751, Republic of Korea (S.-M.P., M.G.K.)
| | - David L Coplin
- Department of Horticulture and Crop Science (J.E.A., J.L., A.L.P.-Q., Do.M., W.Z., J.J.B., Da.M.), Molecular and Cellular Imaging Center-Columbus, Ohio Agricultural Research and Development Center (J.L., S.O.O., J.J.B.), Translational Plant Sciences Graduate Program (I.G.), Center for Applied Plant Sciences (I.G., Da.M.), Department of Plant Pathology (D.L.C.), and Department of Molecular Genetics (Da.M.), Ohio State University, Columbus, Ohio 43210; andCollege of Pharmacy, Research Institute of Pharmaceutical Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-751, Republic of Korea (S.-M.P., M.G.K.)
| | - Joshua J Blakeslee
- Department of Horticulture and Crop Science (J.E.A., J.L., A.L.P.-Q., Do.M., W.Z., J.J.B., Da.M.), Molecular and Cellular Imaging Center-Columbus, Ohio Agricultural Research and Development Center (J.L., S.O.O., J.J.B.), Translational Plant Sciences Graduate Program (I.G.), Center for Applied Plant Sciences (I.G., Da.M.), Department of Plant Pathology (D.L.C.), and Department of Molecular Genetics (Da.M.), Ohio State University, Columbus, Ohio 43210; andCollege of Pharmacy, Research Institute of Pharmaceutical Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-751, Republic of Korea (S.-M.P., M.G.K.)
| | - David Mackey
- Department of Horticulture and Crop Science (J.E.A., J.L., A.L.P.-Q., Do.M., W.Z., J.J.B., Da.M.), Molecular and Cellular Imaging Center-Columbus, Ohio Agricultural Research and Development Center (J.L., S.O.O., J.J.B.), Translational Plant Sciences Graduate Program (I.G.), Center for Applied Plant Sciences (I.G., Da.M.), Department of Plant Pathology (D.L.C.), and Department of Molecular Genetics (Da.M.), Ohio State University, Columbus, Ohio 43210; andCollege of Pharmacy, Research Institute of Pharmaceutical Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-751, Republic of Korea (S.-M.P., M.G.K.)
| |
Collapse
|
21
|
Stork W, Kim JG, Mudgett MB. Functional Analysis of Plant Defense Suppression and Activation by the Xanthomonas Core Type III Effector XopX. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:180-94. [PMID: 25338145 PMCID: PMC4293322 DOI: 10.1094/mpmi-09-14-0263-r] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Many phytopathogenic type III secretion effector proteins (T3Es) have been shown to target and suppress plant immune signaling but perturbation of the plant immune system by T3Es can also elicit a plant response. XopX is a "core" Xanthomonas T3E that contributes to growth and symptom development during Xanthomonas euvesicatoria infection of tomato but its functional role is undefined. We tested the effect of XopX on several aspects of plant immune signaling. XopX promoted ethylene production and plant cell death (PCD) during X. euvesicatoria infection of susceptible tomato and in transient expression assays in Nicotiana benthamiana, which is consistent with its requirement for the development of X. euvesicatoria-induced disease symptoms. Additionally, although XopX suppressed flagellin-induced reactive oxygen species, it promoted the accumulation of pattern-triggered immunity (PTI) gene transcripts. Surprisingly, XopX coexpression with other PCD elicitors resulted in delayed PCD, suggesting antagonism between XopX-dependent PCD and other PCD pathways. However, we found no evidence that XopX contributed to the suppression of effector-triggered immunity during X. euvesicatoria-tomato interactions, suggesting that XopX's primary virulence role is to modulate PTI. These results highlight the dual role of a core Xanthomonas T3E in simultaneously suppressing and activating plant defense responses.
Collapse
|
22
|
Dudnik A, Dudler R. Virulence determinants of Pseudomonas syringae strains isolated from grasses in the context of a small type III effector repertoire. BMC Microbiol 2014; 14:304. [PMID: 25472590 PMCID: PMC4262972 DOI: 10.1186/s12866-014-0304-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 11/20/2014] [Indexed: 11/10/2022] Open
Abstract
Background Pseudomonas syringae is pathogenic to a large number of plant species. For host colonization and disease progression, strains of this bacterium utilize an array of type III-secreted effectors and other virulence factors, including small secreted molecules such as syringolin A, a peptide derivative that inhibits the eukaryotic proteasome. In strains colonizing dicotyledonous plants, the compound was demonstrated to suppress the salicylic-acid-dependent defense pathway. Here, we analyze virulence factors of three strains colonizing wheat (Triticum aestivum): P. syringae pathovar syringae (Psy) strains B64 and SM, as well as P. syringae BRIP34876. These strains have a relatively small repertoire of only seven to eleven type III secreted effectors (T3Es) and differ in their capacity to produce syringolin A. The aim of this study was to analyze the contribution of various known virulence factors in the context of a small T3E repertoire. Results We demonstrate that syringolin A production enhances disease symptom development upon direct infiltration of strains into wheat leaves. However, it is not universally required for colonization, as Psy SM, which lacks syringolin biosynthesis genes, reaches cell densities comparable to syringolin A producer P. syringae BRIP34876. Next, we show that despite the small set of T3E-encoding genes, the type III secretion system remains the key pathogenicity determinant in these strains, and that phenotypic effects of deleting T3E-coding genes become apparent only when multiple effectors are removed. Conclusions Whereas production of syringolin A is not required for successful colonization of wheat leaves by P. syringae strains, its production results in increased lesion formation. Despite the small number of known T3Es encoded by the analyzed strains, the type III secretion system is essential for endophytic growth of these strains. Electronic supplementary material The online version of this article (doi:10.1186/s12866-014-0304-5) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Alexey Dudnik
- Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, Zurich, 8008, Switzerland. .,Present address: Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kogle Allé 4, Hørsholm, 2970, Denmark.
| | - Robert Dudler
- Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, Zurich, 8008, Switzerland.
| |
Collapse
|
23
|
Ruhanen H, Hurley D, Ghosh A, O'Brien KT, Johnston CR, Shields DC. Potential of known and short prokaryotic protein motifs as a basis for novel peptide-based antibacterial therapeutics: a computational survey. Front Microbiol 2014; 5:4. [PMID: 24478765 PMCID: PMC3896991 DOI: 10.3389/fmicb.2014.00004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 01/05/2014] [Indexed: 11/13/2022] Open
Abstract
Short linear motifs (SLiMs) are functional stretches of protein sequence that are of crucial importance for numerous biological processes by mediating protein-protein interactions. These motifs often comprise peptides of less than 10 amino acids that modulate protein-protein interactions. While well-characterized in eukaryotic intracellular signaling, their role in prokaryotic signaling is less well-understood. We surveyed the distribution of known motifs in prokaryotic extracellular and virulence proteins across a range of bacterial species and conducted searches for novel motifs in virulence proteins. Many known motifs in virulence effector proteins mimic eukaryotic motifs and enable the pathogen to control the intracellular processes of their hosts. Novel motifs were detected by finding those that had evolved independently in three or more unrelated virulence proteins. The search returned several significantly over-represented linear motifs of which some were known motifs and others are novel candidates with potential roles in bacterial pathogenesis. A putative C-terminal G[AG].$ motif found in type IV secretion system proteins was among the most significant detected. A KK$ motif that has been previously identified in a plasminogen-binding protein, was demonstrated to be enriched across a number of adhesion and lipoproteins. While there is some potential to develop peptide drugs against bacterial infection based on bacterial peptides that mimic host components, this could have unwanted effects on host signaling. Thus, novel SLiMs in virulence factors that do not mimic host components but are crucial for bacterial pathogenesis, such as the type IV secretion system, may be more useful to develop as leads for anti-microbial peptides or drugs.
Collapse
Affiliation(s)
- Heini Ruhanen
- Complex and Adaptive Systems Laboratory, University College Dublin Dublin, Ireland ; Conway Institute of Biomolecular and Biomedical Science, University College Dublin Dublin, Ireland ; School of Medicine and Medical Science, University College Dublin Dublin, Ireland
| | - Daniel Hurley
- Complex and Adaptive Systems Laboratory, University College Dublin Dublin, Ireland ; Conway Institute of Biomolecular and Biomedical Science, University College Dublin Dublin, Ireland ; School of Medicine and Medical Science, University College Dublin Dublin, Ireland
| | - Ambarnil Ghosh
- Crystallography and Molecular Biology Department, Saha Institute of Nuclear Physics Kolkata, India
| | - Kevin T O'Brien
- Complex and Adaptive Systems Laboratory, University College Dublin Dublin, Ireland ; Conway Institute of Biomolecular and Biomedical Science, University College Dublin Dublin, Ireland ; School of Medicine and Medical Science, University College Dublin Dublin, Ireland
| | | | - Denis C Shields
- Complex and Adaptive Systems Laboratory, University College Dublin Dublin, Ireland ; Conway Institute of Biomolecular and Biomedical Science, University College Dublin Dublin, Ireland ; School of Medicine and Medical Science, University College Dublin Dublin, Ireland
| |
Collapse
|
24
|
Gangadharan A, Sreerekha MV, Whitehill J, Ham JH, Mackey D. The Pseudomonas syringae pv. tomato type III effector HopM1 suppresses Arabidopsis defenses independent of suppressing salicylic acid signaling and of targeting AtMIN7. PLoS One 2013; 8:e82032. [PMID: 24324742 PMCID: PMC3855835 DOI: 10.1371/journal.pone.0082032] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 10/21/2013] [Indexed: 12/31/2022] Open
Abstract
Pseudomonas syringae pv tomato strain DC3000 (Pto) delivers several effector proteins promoting virulence, including HopM1, into plant cells via type III secretion. HopM1 contributes to full virulence of Pto by inducing degradation of Arabidopsis proteins, including AtMIN7, an ADP ribosylation factor-guanine nucleotide exchange factor. Pseudomonas syringae pv phaseolicola strain NPS3121 (Pph) lacks a functional HopM1 and elicits robust defenses in Arabidopsis thaliana, including accumulation of pathogenesis related 1 (PR-1) protein and deposition of callose-containing cell wall fortifications. We have examined the effects of heterologously expressed HopM1Pto on Pph-induced defenses. HopM1 suppresses Pph-induced PR-1 expression, a widely used marker for salicylic acid (SA) signaling and systemic acquired resistance. Surprisingly, HopM1 reduces PR-1 expression without affecting SA accumulation and also suppresses the low levels of PR-1 expression apparent in SA-signaling deficient plants. Further, HopM1 enhances the growth of Pto in SA-signaling deficient plants. AtMIN7 contributes to Pph-induced PR-1 expression. However, HopM1 fails to degrade AtMIN7 during Pph infection and suppresses Pph-induced PR-1 expression and callose deposition in wild-type and atmin7 plants. We also show that the HopM1-mediated suppression of PR-1 expression is not observed in plants lacking the TGA transcription factor, TGA3. Our data indicate that HopM1 promotes bacterial virulence independent of suppressing SA-signaling and links TGA3, AtMIN7, and other HopM1 targets to pathways distinct from the canonical SA-signaling pathway contributing to PR-1 expression and callose deposition. Thus, efforts to understand this key effector must consider multiple targets and unexpected outputs of its action.
Collapse
Affiliation(s)
- Anju Gangadharan
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | - Mysore-Venkatarau Sreerekha
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio, United States of America
| | - Justin Whitehill
- Department of Plant Pathology, The Ohio State University, Columbus, Ohio, United States of America
| | - Jong Hyun Ham
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio, United States of America
| | - David Mackey
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio, United States of America
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
| |
Collapse
|
25
|
Ralstonia solanacearum requires PopS, an ancient AvrE-family effector, for virulence and To overcome salicylic acid-mediated defenses during tomato pathogenesis. mBio 2013; 4:e00875-13. [PMID: 24281716 PMCID: PMC3870264 DOI: 10.1128/mbio.00875-13] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
During bacterial wilt of tomato, the plant pathogen Ralstonia solanacearum upregulates expression of popS, which encodes a type III-secreted effector in the AvrE family. PopS is a core effector present in all sequenced strains in the R. solanacearum species complex. The phylogeny of popS mirrors that of the species complex as a whole, suggesting that this is an ancient, vertically inherited effector needed for association with plants. A popS mutant of R. solanacearum UW551 had reduced virulence on agriculturally important Solanum spp., including potato and tomato plants. However, the popS mutant had wild-type virulence on a weed host, Solanum dulcamara, suggesting that some species can avoid the effects of PopS. The popS mutant was also significantly delayed in colonization of tomato stems compared to the wild type. Some AvrE-type effectors from gammaproteobacteria suppress salicylic acid (SA)-mediated plant defenses, suggesting that PopS, a betaproteobacterial ortholog, has a similar function. Indeed, the popS mutant induced significantly higher expression of tomato SA-triggered pathogenesis-related (PR) genes than the wild type. Further, pretreatment of roots with SA exacerbated the popS mutant virulence defect. Finally, the popS mutant had no colonization defect on SA-deficient NahG transgenic tomato plants. Together, these results indicate that this conserved effector suppresses SA-mediated defenses in tomato roots and stems, which are R. solanacearum’s natural infection sites. Interestingly, PopS did not trigger necrosis when heterologously expressed in Nicotiana leaf tissue, unlike the AvrE homolog DspEPcc from the necrotroph Pectobacterium carotovorum subsp. carotovorum. This is consistent with the differing pathogenesis modes of necrosis-causing gammaproteobacteria and biotrophic R. solanacearum. The type III-secreted AvrE effector family is widely distributed in high-impact plant-pathogenic bacteria and is known to suppress plant defenses for virulence. We characterized the biology of PopS, the only AvrE homolog made by the bacterial wilt pathogen Ralstonia solanacearum. To our knowledge, this is the first study of R. solanacearum effector function in roots and stems, the natural infection sites of this pathogen. Unlike the functionally redundant R. solanacearum effectors studied to date, PopS is required for full virulence and wild-type colonization of two natural crop hosts. R. solanacearum is a biotrophic pathogen that causes a nonnecrotic wilt. Consistent with this, PopS suppressed plant defenses but did not elicit cell death, unlike AvrE homologs from necrosis-causing plant pathogens. We propose that AvrE family effectors have functionally diverged to adapt to the necrotic or nonnecrotic lifestyle of their respective pathogens.
Collapse
|
26
|
HU XIAOPENG, YU JIE, ZHOU XIANG, LI ZHAOMING, XIA YUN, LUO ZHIYONG, WU YAQUN. A small GTPase-like protein fragment of Mycoplasma promotes tumor cell migration and proliferation in vitro via interaction with Rac1 and Stat3. Mol Med Rep 2013; 9:173-9. [DOI: 10.3892/mmr.2013.1766] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 10/21/2013] [Indexed: 11/05/2022] Open
|
27
|
Siamer S, Gaubert S, Boureau T, Brisset MN, Barny MA. Mutational analysis of a predicted double β-propeller domain of the DspA/E effector of Erwinia amylovora. FEMS Microbiol Lett 2013; 342:54-61. [PMID: 23421848 DOI: 10.1111/1574-6968.12108] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 02/07/2013] [Accepted: 02/18/2013] [Indexed: 12/11/2022] Open
Abstract
The bacterium Erwinia amylovora causes fire blight, an invasive disease that threatens apple trees, pear trees and other plants of the Rosaceae family. Erwinia amylovora pathogenicity relies on a type III secretion system and on a single effector DspA/E. This effector belongs to the widespread AvrE family of effectors whose biological function is unknown. In this manuscript, we performed a bioinformatic analysis of DspA/E- and AvrE-related effectors. Motif search identified nuclear localization signals, peroxisome targeting signals, endoplasmic reticulum membrane retention signals and leucine zipper motifs, but none of these motifs were present in all the AvrE-related effectors analysed. Protein threading analysis, however, predicted a conserved double β-propeller domain in the N-terminal part of all the analysed effector sequences. We then performed a random pentapeptide mutagenesis of DspA/E, which led to the characterization of 13 new altered proteins with a five amino acids insertion. Eight harboured the insertion inside the predicted β-propeller domain and six of these eight insertions impaired DspA/E stability or function. Conversely, the two remaining insertions generated proteins that were functional and abundantly secreted in the supernatant suggesting that these two insertions stabilized the protein.
Collapse
|
28
|
Hogan CS, Mole BM, Grant SR, Willis DK, Charkowski AO. The type III secreted effector DspE is required early in solanum tuberosum leaf infection by Pectobacterium carotovorum to cause cell death, and requires Wx(3-6)D/E motifs. PLoS One 2013; 8:e65534. [PMID: 23755246 PMCID: PMC3670860 DOI: 10.1371/journal.pone.0065534] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 04/29/2013] [Indexed: 11/23/2022] Open
Abstract
Pectobacterium species are enterobacterial plant-pathogens that cause soft rot disease in diverse plant species. Unlike hemi-biotrophic plant pathogenic bacteria, the type III secretion system (T3SS) of Pectobacterium carotovorum subsp. carotovorum (P. carotovorum) appears to secrete only one effector protein, DspE. Previously, we found that the T3SS regulator HrpL and the effector DspE are required for P. carotovorum pathogenesis on leaves. Here, we identified genes up-regulated by HrpL, visualized expression of dspE in leaves, and established that DspE causes host cell death. DspE required its full length and WxxxE-like motifs, which are characteristic of the AvrE-family effectors, for host cell death. We also examined expression in plant leaves and showed that hrpL is required for the expression of dspE and hrpN, and that the loss of a functional T3SS had unexpected effects on expression of other genes during leaf infection. These data support a model where P. carotovorum uses the T3SS early in leaf infection to initiate pathogenesis through elicitation of DspE-mediated host cell death.
Collapse
Affiliation(s)
- Clifford S. Hogan
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Beth M. Mole
- Department of Biology and Curriculum in Molecular Biology and Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Sarah R. Grant
- Department of Biology and Curriculum in Molecular Biology and Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - David K. Willis
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Vegetable Crops Research Unit, United States Department of Agriculture – Agricultural Research Service, Madison, Wisconsin, United States of America
| | - Amy O. Charkowski
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| |
Collapse
|
29
|
Degrave A, Moreau M, Launay A, Barny MA, Brisset MN, Patrit O, Taconnat L, Vedel R, Fagard M. The bacterial effector DspA/E is toxic in Arabidopsis thaliana and is required for multiplication and survival of fire blight pathogen. MOLECULAR PLANT PATHOLOGY 2013; 14:506-17. [PMID: 23634775 PMCID: PMC6638835 DOI: 10.1111/mpp.12022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The type III effector DspA/E is an essential pathogenicity factor of the phytopathogenic bacterium Erwinia amylovora. We showed that DspA/E was required for transient bacterial growth in nonhost Arabidopsis thaliana leaves, as an E. amylovora dspA/E mutant was unable to grow. We expressed DspA/E in A. thaliana transgenic plants under the control of an oestradiol-inducible promoter, and found that DspA/E expressed in planta restored the growth of a dspA/E mutant. DspA/E expression in these transgenic plants led to the modulation by at least two-fold of the expression of 384 genes, mostly induced (324 genes). Both induced and repressed genes contained high proportions of defence genes. DspA/E expression ultimately resulted in plant cell death without requiring a functional salicylic acid signalling pathway. Analysis of A. thaliana transgenic seedlings expressing a green fluorescent protein (GFP):DspA/E fusion indicated that the fusion protein could only be detected in a few cells per seedling, suggesting the degradation or absence of accumulation of DspA/E in plant cells. Consistently, we found that DspA/E repressed plant protein synthesis when injected by E. amylovora or when expressed in transgenic plants. Thus, we conclude that DspA/E is toxic to A. thaliana: it promotes modifications, among which the repression of protein synthesis could be determinant in the facilitation of necrosis and bacterial growth.
Collapse
Affiliation(s)
- Alexandre Degrave
- INRA, Laboratoire des Interactions Plantes Pathogènes, UMR217 Paris, France
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Chapman JR, Taylor RK, Weir BS, Romberg MK, Vanneste JL, Luck J, Alexander BJR. Phylogenetic relationships among global populations of Pseudomonas syringae pv. actinidiae. PHYTOPATHOLOGY 2012; 102:1034-44. [PMID: 22877312 DOI: 10.1094/phyto-03-12-0064-r] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
ABSTRACT Pseudomonas syringae pv. actinidiae, the causal agent of canker in kiwifruit (Actinidia spp.) vines, was first detected in Japan in 1984, followed by detections in Korea and Italy in the early 1990s. Isolates causing more severe disease symptoms have recently been detected in several countries with a wide global distribution, including Italy, New Zealand, and China. In order to characterize P. syringae pv. actinidiae populations globally, a representative set of 40 isolates from New Zealand, Italy, Japan, South Korea, Australia, and Chile were selected for extensive genetic analysis. Multilocus sequence analysis (MLSA) of housekeeping, type III effector and phytotoxin genes was used to elucidate the phylogenetic relationships between P. syringae pv. actinidiae isolates worldwide. Four additional isolates, including one from China, for which shotgun sequence of the whole genome was available, were included in phylogenetic analyses. It is shown that at least four P. syringae pv. actinidiae MLSA groups are present globally, and that marker sets with differing evolutionary trajectories (conserved housekeeping and rapidly evolving effector genes) readily differentiate all four groups. The MLSA group designated here as Psa3 is the strain causing secondary symptoms such as formation of cankers, production of exudates, and cane and shoot dieback on some kiwifruit orchards in Italy and New Zealand. It is shown that isolates from Chile also belong to this MLSA group. MLSA group Psa4, detected in isolates collected in New Zealand and Australia, has not been previously described. P. syringae pv. actinidiae has an extensive global distribution yet the isolates causing widespread losses to the kiwifruit industry can all be traced to a single MLSA group, Psa3.
Collapse
Affiliation(s)
- J R Chapman
- Plant Health and Environment Laboratory, Ministry for Primary Industries, P.O. Box 2095, Auckland 1140, New Zealand.
| | | | | | | | | | | | | |
Collapse
|
31
|
Pseudomonas syringae type III effector repertoires: last words in endless arguments. Trends Microbiol 2012; 20:199-208. [PMID: 22341410 DOI: 10.1016/j.tim.2012.01.003] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 12/20/2011] [Accepted: 01/04/2012] [Indexed: 01/10/2023]
Abstract
Many plant pathogens subvert host immunity by injecting compositionally diverse but functionally similar repertoires of cytoplasmic effector proteins. The bacterial pathogen Pseudomonas syringae is a model for exploring the functional structure of such repertoires. The pangenome of P. syringae encodes 57 families of effectors injected by the type III secretion system. Distribution of effector genes among phylogenetically diverse strains reveals a small set of core effectors targeting antimicrobial vesicle trafficking and a much larger set of variable effectors targeting kinase-based recognition processes. Complete disassembly of the 28-effector repertoire of a model strain and reassembly of a minimal functional repertoire reveals the importance of simultaneously attacking both processes. These observations, coupled with growing knowledge of effector targets in plants, support a model for coevolving molecular dialogs between effector repertoires and plant immune systems that emphasizes mutually-driven expansion of the components governing recognition.
Collapse
|
32
|
Siamer S, Patrit O, Fagard M, Belgareh-Touzé N, Barny MA. Expressing the Erwinia amylovora type III effector DspA/E in the yeast Saccharomyces cerevisiae strongly alters cellular trafficking. FEBS Open Bio 2011; 1:23-8. [PMID: 23650572 PMCID: PMC3642059 DOI: 10.1016/j.fob.2011.11.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 11/02/2011] [Accepted: 11/03/2011] [Indexed: 11/18/2022] Open
Abstract
Erwinia amylovora is responsible for fire blight, a necrotic disease of apples and pears. E. amylovora relies on a type III secretion system (T3SS) to induce disease on host plants. DspA/E belongs to the AvrE family of type III effector. Effectors of the AvrE family are injected via the T3SS in plant cell and are important to promote bacterial growth following infection and to suppress plant defense responses. Their mode of action in the plant cells is unknown. Here we study the physiological effects induced by dspA/E expression in the yeast Saccharomyces cerevisiae. Expression of dspA/E in the yeast inhibits cell growth. This growth inhibition is associated with perturbations of the actin cytoskeleton and endocytosis.
Collapse
Affiliation(s)
- Sabrina Siamer
- INRA, UMR217, LIPP, 16 rue Claude Bernard, 75231 Paris cedex 05, France
- UPMC, Université Paris VI, UMR217, LIPP, 16 rue Claude Bernard, 75231 Paris cedex 05, France
- AgroParisTech, UMR217, LIPP, 16 rue Claude Bernard, 75231 Paris cedex 05, France
| | - Oriane Patrit
- INRA, UMR217, LIPP, 16 rue Claude Bernard, 75231 Paris cedex 05, France
- UPMC, Université Paris VI, UMR217, LIPP, 16 rue Claude Bernard, 75231 Paris cedex 05, France
- AgroParisTech, UMR217, LIPP, 16 rue Claude Bernard, 75231 Paris cedex 05, France
| | - Mathilde Fagard
- INRA, UMR217, LIPP, 16 rue Claude Bernard, 75231 Paris cedex 05, France
- UPMC, Université Paris VI, UMR217, LIPP, 16 rue Claude Bernard, 75231 Paris cedex 05, France
- AgroParisTech, UMR217, LIPP, 16 rue Claude Bernard, 75231 Paris cedex 05, France
| | - Naïma Belgareh-Touzé
- FRE 3354 CNRS/UPMC, Institut de Biologie Physico-Chimique, 13 Rue Pierre et Marie Curie, 75005 Paris, France
| | - Marie-Anne Barny
- INRA, UMR217, LIPP, 16 rue Claude Bernard, 75231 Paris cedex 05, France
- UPMC, Université Paris VI, UMR217, LIPP, 16 rue Claude Bernard, 75231 Paris cedex 05, France
- AgroParisTech, UMR217, LIPP, 16 rue Claude Bernard, 75231 Paris cedex 05, France
- Corresponding author at: AgroParisTech, UMR217, LIPP, 16 rue Claude Bernard, 75231 Paris cedex 05, France. Fax: +33 1 44 08 16 98.
| |
Collapse
|
33
|
Roper MC. Pantoea stewartii subsp. stewartii: lessons learned from a xylem-dwelling pathogen of sweet corn. MOLECULAR PLANT PATHOLOGY 2011; 12:628-37. [PMID: 21726365 PMCID: PMC6640275 DOI: 10.1111/j.1364-3703.2010.00698.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
UNLABELLED Pantoea stewartii subsp. stewartii is a Gram-negative enteric bacterium that primarily infects sweet corn. Studies of this bacterium have provided useful insight into how xylem-dwelling bacteria establish themselves and incite disease in their hosts. Pantoea stewartii subsp. stewartii is a remarkable bacterial system for laboratory studies because of its relative ease of propagation and genetic manipulation, and the fact that it appears to employ a minimal number of pathogenicity mechanisms. In addition, P. stewartii subsp. stewartii produces copious amounts of its quorum sensing (QS) signal, acyl-homoserine lactone (AHL), making it an excellent organism for studying QS-controlled gene regulation in a plant-pathogenic bacterium. In fact, P. stewartii subsp. stewartii has become the microbial paradigm for QS control of gene expression by both repression and activation via a QS regulator that binds DNA in the absence and dissociates in the presence of the signal ligand. Moreover, P. stewartii subsp. stewartii is a member of the Enterobacteriaceae, and lessons learned from its interaction with plants may be extrapolated to other plant-associated enterics, such as Erwinia, Dickeya and Pectobacterium spp., or enteric human pathogens associated with plants, such as Escherichia coli and Salmonella spp. TAXONOMY Bacteria; Gammaproteobacteria; family Enterobacteriaceae; genus Pantoea; species stewartii (Mergaert et al., 1993). MICROBIOLOGICAL PROPERTIES Gram-negative, motile, yellow pigmented, mucoid, facultative anaerobe. HOST RANGE Pantoea stewartii subsp. stewartii (Smith, 1898) Dye causes Stewart's wilt of corn (Zea mays). Early-maturing sweet corn varieties and some elite inbred maize lines are particularly susceptible. DISEASE SYMPTOMS There are two major phases of Stewart's wilt disease: (i) wilt and (ii) leaf blight. The wilt phase occurs when young seedlings are infected with P. stewartii subsp. stewartii (Fig. 1A). Water-soaked lesions first appear on the young expanding leaves and, later, seedlings may become severely wilted (Fig. 1B). The plants usually die when infected at the seedling stage. The leaf blight phase occurs when mature plants are infected (Fig. 1C). The bacteria enter the xylem and cause long linear yellow-grey lesions with a wavy margin that run parallel to the leaf veins. These lesions later turn necrotic and dark in colour. The leaf blight phase is most apparent after tasselling and does not generally cause death of the plant. In addition, the bacteria can sometimes break out of the xylem and cause pith rot in mature sweet corn plants. In resistant varieties, lesions are usually limited to only a few centimetres depending on the level of resistance of the particular hybrid (Claflin, 2000; Pataky, 2003). USEFUL WEBSITES http://www.apsnet.org/publications/apsnetfeatures/Pages/StewartsWilt.aspx.
Collapse
Affiliation(s)
- M Caroline Roper
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA 92521, USA.
| |
Collapse
|
34
|
Brown NF, Finlay BB. Potential origins and horizontal transfer of type III secretion systems and effectors. Mob Genet Elements 2011; 1:118-121. [PMID: 22016859 DOI: 10.4161/mge.1.2.16733] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 05/31/2011] [Accepted: 06/01/2011] [Indexed: 11/19/2022] Open
Abstract
A major virulence mechanism used by pathogenic Gram-negative bacteria is the delivery of effector proteins from the bacterial cytoplasm into host cells by type III secretion. Typically, genes encoding type III secretion systems (T3SS) and effectors have been horizontally acquired by the bacteria that employ them. In proteobacteria, and especially Salmonella, and attaching and effacing (A/E) pathogens, the genetic structure of these systems presents as a large locus encoding a T3SS with a small number of effectors, plus numerous small unlinked loci encoding additional individual effectors. We discuss the generation of novel effectors, and the evolution of G+C content following acquisition. We also consider the currently held view that each locus has been acquired individually, as well as propose an alternative where recombination may have redistributed and broken up clusters of effectors. It is clear that the evolution of this virulence strategy is highly complex and challenging to analyze.
Collapse
Affiliation(s)
- Nat F Brown
- Department of Microbiology and Immunology; University of Melbourne; Melbourne, VIC Australia
| | | |
Collapse
|
35
|
Kim HS, Thammarat P, Lommel SA, Hogan CS, Charkowski AO. Pectobacterium carotovorum elicits plant cell death with DspE/F but the P. carotovorum DspE does not suppress callose or induce expression of plant genes early in plant-microbe interactions. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:773-86. [PMID: 21469936 DOI: 10.1094/mpmi-06-10-0143] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The broad-host-range bacterial soft rot pathogen Pectobacterium carotovorum causes a DspE/F-dependent plant cell death on Nicotiana benthamiana within 24 h postinoculation (hpi) followed by leaf maceration within 48 hpi. P. carotovorum strains with mutations in type III secretion system (T3SS) regulatory and structural genes, including the dspE/F operon, did not cause hypersensitive response (HR)-like cell death and or leaf maceration. A strain with a mutation in the type II secretion system caused HR-like plant cell death but no maceration. P. carotovorum was unable to impede callose deposition in N. benthamiana leaves, suggesting that P. carotovorum does not suppress this basal immunity function. Within 24 hpi, there was callose deposition along leaf veins and examination showed that the pathogen cells were localized along the veins. To further examine HR-like plant cell death induced by P. carotovorum, gene expression profiles in N. benthamiana leaves inoculated with wild-type and mutant P. carotovorum and Pseudomonas syringae strains were compared. The N. benthamiana gene expression profile of leaves infiltrated with Pectobacterium carotovorum was similar to leaves infiltrated with a Pseudomonas syringae T3SS mutant. These data support a model where Pectobacterium carotovorum uses the T3SS to induce plant cell death in order to promote leaf maceration rather than to suppress plant immunity.
Collapse
Affiliation(s)
- Hye-Sook Kim
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | | | | | | | | |
Collapse
|
36
|
Effector-triggered immunity blocks pathogen degradation of an immunity-associated vesicle traffic regulator in Arabidopsis. Proc Natl Acad Sci U S A 2011; 108:10774-9. [PMID: 21670267 DOI: 10.1073/pnas.1103338108] [Citation(s) in RCA: 166] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Innate immunity in plants can be triggered by microbe- and pathogen-associated molecular patterns. The pathogen-associated molecular pattern-triggered immunity (PTI) is often suppressed by pathogen effectors delivered into the host cell. Plants can overcome pathogen suppression of PTI and reestablish pathogen resistance through effector-triggered immunity (ETI). An unanswered question is how plants might overcome pathogen-suppression of PTI during ETI. Findings described in this paper suggest a possible mechanism. During Pseudomonas syringae pathovar tomato (Pst) DC3000 infection of Arabidopsis, a host ADP ribosylation factor guanine nucleotide exchange factor, AtMIN7, is destabilized by the pathogen effector HopM1 through the host 26S proteasome. In this study, we discovered that AtMIN7 is required for not only PTI, consistent with the notion that Pst DC3000 degrades AtMIN7 to suppress PTI, but also ETI. The AtMIN7 level in healthy plants is low, but increases posttranscriptionally in response to activation of PTI. Whereas DC3000 infection led to degradation of AtMIN7, activation of ETI by three different effectors, AvrRpt2, AvrPphB, and HopA1, in Col-0 plants blocks the ability of Pst DC3000 to destabilize AtMIN7. Further analyses of bacterial translocation of HopM1 and AtMIN7 stability in HopM1 transgenic plants show that ETI prevents HopM1-mediated degradation of AtMIN7 inside the plant cell. Both AtMIN7 and HopM1 are localized to the trans-Golgi network/early endosome, a subcellular compartment that is not previously known to be associated with bacterial pathogenesis in plants. Thus, blocking pathogen degradation of trans-Golgi network/early endosome-associated AtMIN7 is a critical part of the ETI mechanism to counter bacterial suppression of PTI.
Collapse
|
37
|
Dean P. Functional domains and motifs of bacterial type III effector proteins and their roles in infection. FEMS Microbiol Rev 2011; 35:1100-25. [PMID: 21517912 DOI: 10.1111/j.1574-6976.2011.00271.x] [Citation(s) in RCA: 220] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A key feature of the virulence of many bacterial pathogens is the ability to deliver effector proteins into eukaryotic cells via a dedicated type three secretion system (T3SS). Many bacterial pathogens, including species of Chlamydia, Xanthomonas, Pseudomonas, Ralstonia, Shigella, Salmonella, Escherichia and Yersinia, depend on the T3SS to cause disease. T3SS effectors constitute a large and diverse group of virulence proteins that mimic eukaryotic proteins in structure and function. A salient feature of bacterial effectors is their modular architecture, comprising domains or motifs that confer an array of subversive functions within the eukaryotic cell. These domains/motifs therefore represent a fascinating repertoire of molecular determinants with important roles during infection. This review provides a snapshot of our current understanding of bacterial effector domains and motifs where a defined role in infection has been demonstrated.
Collapse
Affiliation(s)
- Paul Dean
- Institute of Cell and Molecular Bioscience, Medical School, University of Newcastle, Newcastle Upon Tyne, UK.
| |
Collapse
|
38
|
Cunnac S, Chakravarthy S, Kvitko BH, Russell AB, Martin GB, Collmer A. Genetic disassembly and combinatorial reassembly identify a minimal functional repertoire of type III effectors in Pseudomonas syringae. Proc Natl Acad Sci U S A 2011; 108:2975-80. [PMID: 21282655 PMCID: PMC3041132 DOI: 10.1073/pnas.1013031108] [Citation(s) in RCA: 156] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The virulence of Pseudomonas syringae and many other proteobacterial pathogens is dependent on complex repertoires of effector proteins injected into host cells by type III secretion systems. The 28 well-expressed effector genes in the repertoire of the model pathogen P. syringae pv. tomato DC3000 were deleted to produce polymutant DC3000D28E. Growth of DC3000D28E in Nicotiana benthamiana was symptomless and 4 logs lower than that of DC3000ΔhopQ1-1, which causes disease in this model plant. DC3000D28E seemed functionally effectorless but otherwise WT in diagnostic phenotypes relevant to plant interactions (for example, ability to inject the AvrPto-Cya reporter into N. benthamiana). Various effector genes were integrated by homologous recombination into native loci or by a programmable or random in vivo assembly shuttle (PRIVAS) system into the exchangeable effector locus in the Hrp pathogenicity island of DC3000D28E. The latter method exploited dual adapters and recombination in yeast for efficient assembly of PCR products into programmed or random combinations of multiple effector genes. Native and PRIVAS-mediated integrations were combined to identify a minimal functional repertoire of eight effector genes that restored much of the virulence of DC3000ΔhopQ1-1 in N. benthamiana, revealing a hierarchy in effector function: AvrPtoB acts with priority in suppressing immunity, enabling other effectors to promote further growth (HopM1 and HopE1), chlorosis (HopG1), lesion formation (HopAM1-1), and near full growth and symptom production (AvrE, HopAA1-1, and/or HopN1 functioning synergistically with the previous effectors). DC3000D28E, the PRIVAS method, and minimal functional repertoires provide new resources for probing the plant immune system.
Collapse
Affiliation(s)
- Sébastien Cunnac
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853; and
| | - Suma Chakravarthy
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853; and
| | - Brian H. Kvitko
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853; and
| | - Alistair B. Russell
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853; and
| | - Gregory B. Martin
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853; and
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853
| | - Alan Collmer
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853; and
| |
Collapse
|
39
|
Beattie GA. Water relations in the interaction of foliar bacterial pathogens with plants. ANNUAL REVIEW OF PHYTOPATHOLOGY 2011; 49:533-55. [PMID: 21438680 DOI: 10.1146/annurev-phyto-073009-114436] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
This review examines the many ways in which water influences the relations between foliar bacterial pathogens and plants. As a limited resource in aerial plant tissues, water is subject to manipulation by both plants and pathogens. A model is emerging that suggests that plants actively promote localized desiccation at the infection site and thus restrict pathogen growth as one component of defense. Similarly, many foliar pathogens manipulate water relations as one component of pathogenesis. Nonvascular pathogens do this using effectors and other molecules to alter hormonal responses and enhance intercellular watersoaking, whereas vascular pathogens use many mechanisms to cause wilt. Because of water limitations on phyllosphere surfaces, bacterial colonists, including pathogens, benefit from the protective effects of cellular aggregation, synthesis of hygroscopic polymers, and uptake and production of osmoprotective compounds. Moreover, these bacteria employ tactics for scavenging and distributing water to overcome water-driven barriers to nutrient acquisition, movement, and signal exchange on plant surfaces.
Collapse
Affiliation(s)
- Gwyn A Beattie
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, Iowa 50011-3211, USA.
| |
Collapse
|
40
|
Clarke CR, Cai R, Studholme DJ, Guttman DS, Vinatzer BA. Pseudomonas syringae strains naturally lacking the classical P. syringae hrp/hrc Locus are common leaf colonizers equipped with an atypical type III secretion system. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:198-210. [PMID: 20064063 DOI: 10.1094/mpmi-23-2-0198] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Pseudomonas syringae is best known as a plant pathogen that causes disease by translocating immune-suppressing effector proteins into plant cells through a type III secretion system (T3SS). However, P. syringae strains belonging to a newly described phylogenetic subgroup (group 2c) are missing the canonical P. syringae hrp/hrc cluster coding for a T3SS, flanking effector loci, and any close orthologue of known P. syringae effectors. Nonetheless, P. syringae group 2c strains are common leaf colonizers and grow on some tested plant species to population densities higher than those obtained by other P. syringae strains on nonhost species. Moreover, group 2c strains have genes necessary for the production of phytotoxins, have an ice nucleation gene, and, most interestingly, contain a novel hrp/hrc cluster, which is only distantly related to the canonical P. syringae hrp/hrc cluster. This hrp/hrc cluster appears to encode a functional T3SS although the genes hrpK and hrpS, present in the classical P. syringae hrp/hrc cluster, are missing. The genome sequence of a representative group 2c strain also revealed distant orthologues of the P. syringae effector genes avrE1 and hopM1 and the P. aeruginosa effector genes exoU and exoY. A putative life cycle for group 2c P. syringae is discussed.
Collapse
Affiliation(s)
- Christopher R Clarke
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Latham Hall, Ag Quad Lane, Blacksburg 24061, USA
| | | | | | | | | |
Collapse
|
41
|
Schneider DJ, Collmer A. Studying plant-pathogen interactions in the genomics era: beyond molecular Koch's postulates to systems biology. ANNUAL REVIEW OF PHYTOPATHOLOGY 2010; 48:457-479. [PMID: 20687834 DOI: 10.1146/annurev-phyto-073009-114411] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Molecular factors enabling microbial pathogens to cause plant diseases have been sought with increasing efficacy over three research eras that successively introduced the tools of disease physiology, single-gene molecular genetics, and genomics. From this work emerged a unified model of the interactions of biotrophic and hemibiotrophic pathogens, which posits that successful pathogens typically defeat two levels of plant defense by translocating cytoplasmic effectors that suppress the first defense (surface arrayed against microbial signatures) while evading the second defense (internally arrayed against effectors). As is predicted from this model and confirmed by sequence pattern-driven discovery of large repertoires of cytoplasmic effectors in the genomes of many pathogens, the coevolution of (hemi)biotrophic pathogens and their hosts has generated pathosystems featuring extreme complexity and apparent robustness. These findings highlight the need for a fourth research era of systems biology in which virulence factors are studied as pathosystem components, and pathosystems are studied for their emergent properties.
Collapse
Affiliation(s)
- David J Schneider
- U.S. Department of Agriculture, Agricultural Research Service, Robert W. Holley Center for Agriculture and Health, Ithaca, New York 14853, USA.
| | | |
Collapse
|