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Dulal N, Wilson RA. Paths of Least Resistance: Unconventional Effector Secretion by Fungal and Oomycete Plant Pathogens. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024:MPMI12230212CR. [PMID: 38949402 DOI: 10.1094/mpmi-12-23-0212-cr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Effector secretion by different routes mediates the molecular interplay between host plant and pathogen, but mechanistic details in eukaryotes are sparse. This may limit the discovery of new effectors that could be utilized for improving host plant disease resistance. In fungi and oomycetes, apoplastic effectors are secreted via the conventional endoplasmic reticulum (ER)-Golgi pathway, while cytoplasmic effectors are packaged into vesicles that bypass Golgi in an unconventional protein secretion (UPS) pathway. In Magnaporthe oryzae, the Golgi bypass UPS pathway incorporates components of the exocyst complex and a t-SNARE, presumably to fuse Golgi bypass vesicles to the fungal plasma membrane. Upstream, cytoplasmic effector mRNA translation in M. oryzae requires the efficient decoding of AA-ending codons. This involves the modification of wobble uridines in the anticodon loop of cognate tRNAs and fine-tunes cytoplasmic effector translation and secretion rates to maintain biotrophic interfacial complex integrity and permit host infection. Thus, plant-fungal interface integrity is intimately tied to effector codon usage, which is a surprising constraint on pathogenicity. Here, we discuss these findings within the context of fungal and oomycete effector discovery, delivery, and function in host cells. We show how cracking the codon code for unconventional cytoplasmic effector secretion in M. oryzae has revealed AA-ending codon usage bias in cytoplasmic effector mRNAs across kingdoms, including within the RxLR-dEER motif-encoding sequence of a bona fide Phytophthora infestans cytoplasmic effector, suggesting its subjection to translational speed control. By focusing on recent developments in understanding unconventional effector secretion, we draw attention to this important but understudied area of host-pathogen interactions. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Nawaraj Dulal
- Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE, U.S.A
| | - Richard A Wilson
- Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE, U.S.A
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Fu Q, Chen T, Wang Y, Zhou H, Zhang K, Zheng R, Zhang Y, Liu R, Yin X, Liu G, Xu Y. Plasmopara viticola effector PvCRN20 represses the import of VvDEG5 into chloroplasts to suppress immunity in grapevine. THE NEW PHYTOLOGIST 2024; 243:2311-2331. [PMID: 39091140 DOI: 10.1111/nph.20002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 07/03/2024] [Indexed: 08/04/2024]
Abstract
Chloroplasts play a crucial role in plant defense against pathogens, making them primary targets for pathogen effectors that suppress host immunity. This study characterizes the Plasmopara viticola CRN-like effector, PvCRN20, which interacts with DEG5 in the cytoplasm but not with its interacting protein, DEG8, which is located in the chloroplast. By transiently overexpressing in tobacco leaves, we show that PvCRN20 could inhibit INF1- and Bax-triggered cell death. Constitutive expression of PvCRN20 suppresses the accumulation of reactive oxygen species (ROS) and promotes pathogen colonization. PvCRN20 reduces DEG5 entry into chloroplasts, thereby disrupting DEG5 and DEG8 interactions in chloroplasts. Overexpression of VvDEG5 and VvDEG8 induces ROS accumulation and enhances grapevine resistance to P. viticola, whereas knockout of VvDEG8 represses ROS production and promotes P. viticola colonization. Consistently, ectopic expression of VvDEG5 and VvDEG8 in tobacco promotes chloroplast-derived ROS accumulation, whereas co-expression of PvCRN20 counteracted this promotion by VvDEG5. Therefore, DEG5 is essential for the virulence function of PvCRN20. Although PvCRN20 is located in both the nucleus and cytoplasm, only cytoplasmic PvCRN20 suppresses plant immunity and promotes pathogen infection. Our results reveal that PvCRN20 dampens plant defenses by repressing the chloroplast import of DEG5, thus reducing host ROS accumulation and facilitating pathogen colonization.
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Affiliation(s)
- Qingqing Fu
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Tingting Chen
- College of Agricultural Science, Xichang University, Xichang, 615000, China
| | - Yunlei Wang
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Huixuan Zhou
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Kangzhuang Zhang
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Runlong Zheng
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Yanan Zhang
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Ruiqi Liu
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Xiao Yin
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Guotian Liu
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Yan Xu
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
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Vo NNT, Yang A, Leesutthiphonchai W, Liu Y, Hughes TR, Judelson HS. Transcription factor binding specificities of the oomycete Phytophthora infestans reflect conserved and divergent evolutionary patterns and predict function. BMC Genomics 2024; 25:710. [PMID: 39044130 PMCID: PMC11267843 DOI: 10.1186/s12864-024-10630-6] [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: 02/13/2024] [Accepted: 07/17/2024] [Indexed: 07/25/2024] Open
Abstract
BACKGROUND Identifying the DNA-binding specificities of transcription factors (TF) is central to understanding gene networks that regulate growth and development. Such knowledge is lacking in oomycetes, a microbial eukaryotic lineage within the stramenopile group. Oomycetes include many important plant and animal pathogens such as the potato and tomato blight agent Phytophthora infestans, which is a tractable model for studying life-stage differentiation within the group. RESULTS Mining of the P. infestans genome identified 197 genes encoding proteins belonging to 22 TF families. Their chromosomal distribution was consistent with family expansions through unequal crossing-over, which were likely ancient since each family had similar sizes in most oomycetes. Most TFs exhibited dynamic changes in RNA levels through the P. infestans life cycle. The DNA-binding preferences of 123 proteins were assayed using protein-binding oligonucleotide microarrays, which succeeded with 73 proteins from 14 families. Binding sites predicted for representatives of the families were validated by electrophoretic mobility shift or chromatin immunoprecipitation assays. Consistent with the substantial evolutionary distance of oomycetes from traditional model organisms, only a subset of the DNA-binding preferences resembled those of human or plant orthologs. Phylogenetic analyses of the TF families within P. infestans often discriminated clades with canonical and novel DNA targets. Paralogs with similar binding preferences frequently had distinct patterns of expression suggestive of functional divergence. TFs were predicted to either drive life stage-specific expression or serve as general activators based on the representation of their binding sites within total or developmentally-regulated promoters. This projection was confirmed for one TF using synthetic and mutated promoters fused to reporter genes in vivo. CONCLUSIONS We established a large dataset of binding specificities for P. infestans TFs, representing the first in the stramenopile group. This resource provides a basis for understanding transcriptional regulation by linking TFs with their targets, which should help delineate the molecular components of processes such as sporulation and host infection. Our work also yielded insight into TF evolution during the eukaryotic radiation, revealing both functional conservation as well as diversification across kingdoms.
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Affiliation(s)
- Nguyen N T Vo
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, 92521, USA
| | - Ally Yang
- Department of Molecular Genetics and Donnelly Center, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Wiphawee Leesutthiphonchai
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, 92521, USA
- Current address: Department of Plant Pathology, Faculty of Agriculture, Kasetsart University, Bangkok, 10900, Thailand
| | - Yulong Liu
- Department of Molecular Genetics and Donnelly Center, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Timothy R Hughes
- Department of Molecular Genetics and Donnelly Center, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Howard S Judelson
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, 92521, USA.
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Qian H, Lin L, Zhang Z, Gu X, Shen D, Yin Z, Ye W, Dou D, Wang Y. A MYB-related transcription factor regulates effector gene expression in an oomycete pathogen. MOLECULAR PLANT PATHOLOGY 2024; 25:e13468. [PMID: 38808392 PMCID: PMC11134190 DOI: 10.1111/mpp.13468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/01/2024] [Accepted: 05/08/2024] [Indexed: 05/30/2024]
Abstract
Phytophthora pathogens possess hundreds of effector genes that exhibit diverse expression patterns during infection, yet how the expression of effector genes is precisely regulated remains largely elusive. Previous studies have identified a few potential conserved transcription factor binding sites (TFBSs) in the promoters of Phytophthora effector genes. Here, we report a MYB-related protein, PsMyb37, in Phytophthora sojae, the major causal agent of root and stem rot in soybean. Yeast one-hybrid and electrophoretic mobility shift assays showed that PsMyb37 binds to the TACATGTA motif, the most prevalent TFBS in effector gene promoters. The knockout mutant of PsMyb37 exhibited significantly reduced virulence on soybean and was more sensitive to oxidative stress. Consistently, transcriptome analysis showed that numerous effector genes associated with suppressing plant immunity or scavenging reactive oxygen species were down-regulated in the PsMyb37 knockout mutant during infection compared to the wild-type P. sojae. Several promoters of effector genes were confirmed to drive the expression of luciferase in a reporter assay. These results demonstrate that a MYB-related transcription factor contributes to the expression of effector genes in P. sojae.
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Affiliation(s)
- Hui Qian
- Department of Plant PathologyNanjing Agricultural UniversityNanjingJiangsuChina
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs)Nanjing Agricultural UniversityNanjingJiangsuChina
| | - Long Lin
- Department of Plant PathologyNanjing Agricultural UniversityNanjingJiangsuChina
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs)Nanjing Agricultural UniversityNanjingJiangsuChina
| | - Zhichao Zhang
- Department of Plant PathologyNanjing Agricultural UniversityNanjingJiangsuChina
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs)Nanjing Agricultural UniversityNanjingJiangsuChina
| | - Xinyi Gu
- Department of Plant PathologyNanjing Agricultural UniversityNanjingJiangsuChina
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs)Nanjing Agricultural UniversityNanjingJiangsuChina
| | - Danyu Shen
- Department of Plant PathologyNanjing Agricultural UniversityNanjingJiangsuChina
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs)Nanjing Agricultural UniversityNanjingJiangsuChina
| | - Zhiyuan Yin
- Department of Plant PathologyNanjing Agricultural UniversityNanjingJiangsuChina
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs)Nanjing Agricultural UniversityNanjingJiangsuChina
| | - Wenwu Ye
- Department of Plant PathologyNanjing Agricultural UniversityNanjingJiangsuChina
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs)Nanjing Agricultural UniversityNanjingJiangsuChina
| | - Daolong Dou
- Department of Plant PathologyNanjing Agricultural UniversityNanjingJiangsuChina
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs)Nanjing Agricultural UniversityNanjingJiangsuChina
| | - Yuanchao Wang
- Department of Plant PathologyNanjing Agricultural UniversityNanjingJiangsuChina
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs)Nanjing Agricultural UniversityNanjingJiangsuChina
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Wang S, McLellan H, Boevink PC, Birch PRJ. RxLR Effectors: Master Modulators, Modifiers and Manipulators. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2023; 36:754-763. [PMID: 37750829 DOI: 10.1094/mpmi-05-23-0054-cr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Cytoplasmic effectors with an Arg-any amino acid-Arg-Leu (RxLR) motif are encoded by hundreds of genes within the genomes of oomycete Phytophthora spp. and downy mildew pathogens. There has been a dramatic increase in our understanding of the evolution, function, and recognition of these effectors. Host proteins with a wide range of subcellular localizations and functions are targeted by RxLR effectors. Many processes are manipulated, including transcription, post-translational modifications, such as phosphorylation and ubiquitination, secretion, and intracellular trafficking. This involves an array of RxLR effector modes-of-action, including stabilization or destabilization of protein targets, altering or disrupting protein complexes, inhibition or utility of target enzyme activities, and changing the location of protein targets. Interestingly, approximately 50% of identified host proteins targeted by RxLR effectors are negative regulators of immunity. Avirulence RxLR effectors may be directly or indirectly detected by nucleotide-binding leucine-rich repeat resistance (NLR) proteins. Direct recognition by a single NLR of RxLR effector orthologues conserved across multiple Phytophthora pathogens may provide wide protection of diverse crops. Failure of RxLR effectors to interact with or appropriately manipulate target proteins in nonhost plants has been shown to restrict host range. This knowledge can potentially be exploited to alter host targets to prevent effector interaction, providing a barrier to host infection. Finally, recent evidence suggests that RxLR effectors, like cytoplasmic effectors from fungal pathogen Magnaporthe oryzae, may enter host cells via clathrin-mediated endocytosis. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Shumei Wang
- Department of Microbiology and Plant Pathology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA, U.S.A
| | - Hazel McLellan
- Division of Plant Sciences, School of Life Sciences, University of Dundee, at James Hutton Institute, Invergowrie, Dundee DD2 5DA, U.K
| | - Petra C Boevink
- Cell and Molecular Sciences, James Hutton Institute, Invergowrie, Dundee DD2 5DA, U.K
| | - Paul R J Birch
- Division of Plant Sciences, School of Life Sciences, University of Dundee, at James Hutton Institute, Invergowrie, Dundee DD2 5DA, U.K
- Cell and Molecular Sciences, James Hutton Institute, Invergowrie, Dundee DD2 5DA, U.K
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Chepsergon J, Moleleki LN. "Order from disordered": Potential role of intrinsically disordered regions in phytopathogenic oomycete intracellular effector proteins. CURRENT OPINION IN PLANT BIOLOGY 2023; 75:102402. [PMID: 37329857 DOI: 10.1016/j.pbi.2023.102402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 05/13/2023] [Accepted: 05/17/2023] [Indexed: 06/19/2023]
Abstract
There is a continuous arms race between pathogens and their host plants. However, successful pathogens, such as phytopathogenic oomycetes, secrete effector proteins to manipulate host defense responses for disease development. Structural analyses of these effector proteins reveal the existence of regions that fail to fold into three-dimensional structures, intrinsically disordered regions (IDRs). Because of their flexibility, these regions are involved in important biological functions of effector proteins, such as effector-host protein interactions that perturb host immune responses. Despite their significance, the role of IDRs in phytopathogenic oomycete effector-host protein interactions is not clear. This review, therefore, searched the literature for functionally characterized oomycete intracellular effectors with known host interactors. We further classify regions that mediate effector-host protein interactions into globular or disordered binding sites in these proteins. To fully appreciate the potential role of IDRs, five effector proteins encoding potential disordered binding sites were used as case studies. We also propose a pipeline that can be used to identify, classify as well as characterize potential binding regions in effector proteins. Understanding the role of IDRs in these effector proteins can aid in the development of new disease-control strategies.
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Affiliation(s)
- Jane Chepsergon
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Lucy Novungayo Moleleki
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa.
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Sabnam N, Hussain A, Saha P. The secret password: Cell death-inducing proteins in filamentous phytopathogens - As versatile tools to develop disease-resistant crops. Microb Pathog 2023; 183:106276. [PMID: 37541554 DOI: 10.1016/j.micpath.2023.106276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 07/25/2023] [Accepted: 07/27/2023] [Indexed: 08/06/2023]
Abstract
Cell death-inducing proteins (CDIPs) are some of the secreted effector proteins manifested by filamentous oomycetes and fungal pathogens to invade the plant tissue and facilitate infection. Along with their involvement in different developmental processes and virulence, CDIPs play a crucial role in plant-pathogen interactions. As the name implies, CDIPs cause necrosis and trigger localised cell death in the infected host tissues by the accumulation of higher concentrations of hydrogen peroxide (H2O2), oxidative burst, accumulation of nitric oxide (NO), and electrolyte leakage. They also stimulate the biosynthesis of defense-related phytohormones such as salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA), and ethylene (ET), as well as the expression of pathogenesis-related (PR) genes that are important in disease resistance. Altogether, the interactions result in the hypersensitive response (HR) in the host plant, which might confer systemic acquired resistance (SAR) in some cases against a vast array of related and unrelated pathogens. The CDIPs, due to their capability of inducing host resistance, are thus unique among the array of proteins secreted by filamentous plant pathogens. More interestingly, a few transgenic plant lines have also been developed expressing the CDIPs with added resistance. Thus, CDIPs have opened an interesting hot area of research. The present study critically reviews the current knowledge of major types of CDIPs identified across filamentous phytopathogens and their modes of action in the last couple of years. This review also highlights the recent breakthrough technologies in studying plant-pathogen interactions as well as crop improvement by enhancing disease resistance through CDIPs.
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Affiliation(s)
- Nazmiara Sabnam
- Department of Life Sciences, Presidency University, Kolkata, India.
| | - Afzal Hussain
- Department of Bioinformatics, Maulana Azad National Institute of Technology, Bhopal, India
| | - Pallabi Saha
- Biotechnology Institute, University of Minnesota, Saint Paul, Minnesota, 55108, United States; Department of Biotechnology, National Institute of Technology, Durgapur, India
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8
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Stuer N, Van Damme P, Goormachtig S, Van Dingenen J. Seeking the interspecies crosswalk for filamentous microbe effectors. TRENDS IN PLANT SCIENCE 2023; 28:1045-1059. [PMID: 37062674 DOI: 10.1016/j.tplants.2023.03.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 03/02/2023] [Accepted: 03/18/2023] [Indexed: 06/19/2023]
Abstract
Both pathogenic and symbiotic microorganisms modulate the immune response and physiology of their host to establish a suitable niche. Key players in mediating colonization outcome are microbial effector proteins that act either inside (cytoplasmic) or outside (apoplastic) the plant cells and modify the abundance or activity of host macromolecules. We compile novel insights into the much-disputed processes of effector secretion and translocation of filamentous organisms, namely fungi and oomycetes. We report how recent studies that focus on unconventional secretion and effector structure challenge the long-standing image of effectors as conventionally secreted proteins that are translocated with the aid of primary amino acid sequence motifs. Furthermore, we emphasize the potential of diverse, unbiased, state-of-the-art proteomics approaches in the holistic characterization of fungal and oomycete effectomes.
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Affiliation(s)
- Naomi Stuer
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium
| | - Petra Van Damme
- iRIP Unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Karel Lodewijk Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Sofie Goormachtig
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium.
| | - Judith Van Dingenen
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium.
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9
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Sharma S, Prasad A, Prasad M. Ubiquitination from the perspective of plant pathogens. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:4367-4376. [PMID: 37226440 DOI: 10.1093/jxb/erad191] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/18/2023] [Indexed: 05/26/2023]
Abstract
The constant battle of survival between pathogens and host plants has played a crucial role in shaping the course of their co-evolution. However, the major determinants of the outcome of this ongoing arms race are the effectors secreted by pathogens into host cells. These effectors perturb the defense responses of plants to promote successful infection. In recent years, extensive research in the area of effector biology has reported an increase in the repertoire of pathogenic effectors that mimic or target the conserved ubiquitin-proteasome pathway. The role of the ubiquitin-mediated degradation pathway is well known to be indispensable for various aspects of a plant's life, and thus targeting or mimicking it seems to be a smart strategy adopted by pathogens. Therefore, this review summarizes recent findings on how some pathogenic effectors mimic or act as one of the components of the ubiquitin-proteasome machinery while others directly target the plant's ubiquitin-proteasome system.
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Affiliation(s)
| | - Ashish Prasad
- Department of Botany, Kurukshetra University, Kurukshetra, India
| | - Manoj Prasad
- National Institute of Plant Genome Research, New Delhi, India
- Department of Plant Sciences, University of Hyderabad, Hyderabad, India
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10
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Breeze E, Vale V, McLellan H, Pecrix Y, Godiard L, Grant M, Frigerio L. A tell tail sign: a conserved C-terminal tail-anchor domain targets a subset of pathogen effectors to the plant endoplasmic reticulum. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:3188-3202. [PMID: 36860200 DOI: 10.1093/jxb/erad075] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 02/27/2023] [Indexed: 05/21/2023]
Abstract
The endoplasmic reticulum (ER) is the entry point to the secretory pathway and, as such, is critical for adaptive responses to biotic stress, when the demand for de novo synthesis of immunity-related proteins and signalling components increases significantly. Successful phytopathogens have evolved an arsenal of small effector proteins which collectively reconfigure multiple host components and signalling pathways to promote virulence; a small, but important, subset of which are targeted to the endomembrane system including the ER. We identified and validated a conserved C-terminal tail-anchor motif in a set of pathogen effectors known to localize to the ER from the oomycetes Hyaloperonospora arabidopsidis and Plasmopara halstedii (downy mildew of Arabidopsis and sunflower, respectively) and used this protein topology to develop a bioinformatic pipeline to identify putative ER-localized effectors within the effectorome of the related oomycete, Phytophthora infestans, the causal agent of potato late blight. Many of the identified P. infestans tail-anchor effectors converged on ER-localized NAC transcription factors, indicating that this family is a critical host target for multiple pathogens.
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Affiliation(s)
- Emily Breeze
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Victoria Vale
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Hazel McLellan
- Division of Plant Science, University of Dundee (at JHI), Invergowrie, Dundee DD2 5DA, UK
| | - Yann Pecrix
- CIRAD, UMR PVBMT, Peuplements Végétaux et Bioagresseurs en Milieu Tropical (UMR C53), Ligne Paradis, 97410 St Pierre, La Réunion, France
| | - Laurence Godiard
- Laboratoire des Interactions Plantes Microbes Environnement (LIPME), Institut National de Recherche pour l'Agriculture, l'Alimentation, et l'Environnement (INRAE), Centre National de la Recherche Scientifique (CNRS), Université de Toulouse, Castanet-Tolosan, France
| | - Murray Grant
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Lorenzo Frigerio
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
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Wang N, Yin Z, Wu Y, Yang J, Zhao Y, Daly P, Pei Y, Zhou D, Dou D, Wei L. A Pythium myriotylum Small Cysteine-Rich Protein Triggers Immune Responses in Diverse Plant Hosts. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2023; 36:283-293. [PMID: 37022145 DOI: 10.1094/mpmi-09-22-0187-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The oomycete Pythium myriotylum is a necrotrophic pathogen that infects many crop species worldwide, including ginger, soybean, tomato, and tobacco. Here, we identified a P. myriotylum small cysteine-rich protein, PmSCR1, that induces cell death in Nicotiana benthamiana by screening small, secreted proteins that were induced during infection of ginger and did not have a predicted function at the time of selection. Orthologs of PmSCR1 were found in other Pythium species, but these did not have cell death-inducing activity in N. benthamiana. PmSCR1 encodes a protein containing an auxiliary activity 17 family domain and triggers multiple immune responses in host plants. The elicitor function of PmSCR1 appears to be independent of enzymatic activity, because the heat inactivation of PmSCR1 protein did not affect PmSCR1-induced cell death or other defense responses. The elicitor function of PmSCR1 was also independent of BAK1 and SOBIR1. Furthermore, a small region of the protein, PmSCR186-211, is sufficient for inducing cell death. A pretreatment using the full-length PmSCR1 protein promoted the resistance of soybean and N. benthamiana to Phytophthora sojae and Phytophthora capsici infection, respectively. These results reveal that PmSCR1 is a novel elicitor from P. myriotylum, which exhibits plant immunity-inducing activity in multiple host plants. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Nan Wang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Zhiyuan Yin
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Yingke Wu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Jishuo Yang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian, China
| | - Yaning Zhao
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Paul Daly
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Yong Pei
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Dongmei Zhou
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Daolong Dou
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Lihui Wei
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
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12
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Jeon H, Segonzac C. Manipulation of the Host Endomembrane System by Bacterial Effectors. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2023; 36:208-217. [PMID: 36645655 DOI: 10.1094/mpmi-09-22-0190-fi] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The endomembrane system, extending from the nuclear envelope to the plasma membrane, is critical to the plant response to pathogen infection. Synthesis and transport of immunity-related proteins and antimicrobial compounds to and from the plasma membrane are supported by conventional and unconventional processes of secretion and internalization of vesicles, guided by the cytoskeleton networks. Although plant bacterial pathogens reside mostly in the apoplast, major structural and functional modifications of the endomembrane system in the host cell occur during bacterial infection. Here, we review the dynamics of these cellular compartments, briefly, for their essential contributions to the plant defense responses and, in parallel, for their emerging roles in bacterial pathogenicity. We further focus on Pseudomonas syringae, Xanthomonas spp., and Ralstonia solanacearum type III secreted effectors that one or both localize to and associate with components of the host endomembrane system or the cytoskeleton network to highlight the diversity of virulence strategies deployed by bacterial pathogens beyond the inhibition of the secretory pathway. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Hyelim Jeon
- Department of Agriculture, Forestry and Bioresources, Seoul National University, Seoul, 08826, Republic of Korea
- Plant Immunity Research Center, Seoul National University, Seoul 08826, Republic of Korea
| | - Cécile Segonzac
- Department of Agriculture, Forestry and Bioresources, Seoul National University, Seoul, 08826, Republic of Korea
- Plant Immunity Research Center, Seoul National University, Seoul 08826, Republic of Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, 08826, Republic of Korea
- Agricultural and Life Science Research Institute, Seoul National University, Seoul, 08826, Republic of Korea
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Combier M, Evangelisti E, Piron MC, Schornack S, Mestre P. Candidate effector proteins from the oomycetes Plasmopara viticola and Phytophthora parasitica share similar predicted structures and induce cell death in Nicotiana species. PLoS One 2022; 17:e0278778. [PMID: 36459530 PMCID: PMC9718384 DOI: 10.1371/journal.pone.0278778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 11/22/2022] [Indexed: 12/04/2022] Open
Abstract
Effector proteins secreted by plant pathogens are essential for infection. Cytoplasmic RXLR effectors from oomycetes are characterized by the presence of RXLR and EER motifs that are frequently linked to WY- and/or LWY-domains, folds that are exclusive to this effector family. A related family of secreted candidate effector proteins, carrying WY-domains and the EER motif but lacking the canonical RXLR motif, has recently been described in oomycetes and is mainly found in downy mildew pathogens. Plasmopara viticola is an obligate biotrophic oomycete causing grapevine downy mildew. Here we describe a conserved Pl. viticola secreted candidate non-RXLR effector protein with cell death-inducing activity in Nicotiana species. A similar RXLR effector candidate from the broad host range oomycete pathogen Phytophthora parasitica also induces cell death in Nicotiana. Through comparative tertiary structure modelling, we reveal that both proteins are predicted to carry WY- and LWY-domains. Our work supports the presence of LWY-domains in non-RXLR effectors and suggests that effector candidates with similar domain architecture may exert similar activities.
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Affiliation(s)
- Maud Combier
- SVQV, UMR-A 1131, Université de Strasbourg, INRAE, Colmar, France
| | - Edouard Evangelisti
- Sainsbury Laboratory (SLCU), University of Cambridge, Cambridge, United Kingdom
| | | | - Sebastian Schornack
- Sainsbury Laboratory (SLCU), University of Cambridge, Cambridge, United Kingdom
| | - Pere Mestre
- SVQV, UMR-A 1131, Université de Strasbourg, INRAE, Colmar, France
- * E-mail:
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Helm M, Singh R, Hiles R, Jaiswal N, Myers A, Iyer-Pascuzzi AS, Goodwin SB. Candidate Effector Proteins from the Maize Tar Spot Pathogen Phyllachora maydis Localize to Diverse Plant Cell Compartments. PHYTOPATHOLOGY 2022; 112:2538-2548. [PMID: 35815936 DOI: 10.1094/phyto-05-22-0181-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Most fungal pathogens secrete effector proteins into host cells to modulate their immune responses, thereby promoting pathogenesis and fungal growth. One such fungal pathogen is the ascomycete Phyllachora maydis, which causes tar spot disease on leaves of maize (Zea mays). Sequencing of the P. maydis genome revealed 462 putatively secreted proteins, of which 40 contain expected effector-like sequence characteristics. However, the subcellular compartments targeted by P. maydis effector candidate (PmEC) proteins remain unknown, and it will be important to prioritize them for further functional characterization. To test the hypothesis that PmECs target diverse subcellular compartments, cellular locations of super yellow fluorescent protein-tagged PmEC proteins were identified using a Nicotiana benthamiana-based heterologous expression system. Immunoblot analyses showed that most of the PmEC-fluorescent protein fusions accumulated protein in N. benthamiana, indicating that the candidate effectors could be expressed in dicot leaf cells. Laser-scanning confocal microscopy of N. benthamiana epidermal cells revealed that most of the P. maydis putative effectors localized to the nucleus and cytosol. One candidate effector, PmEC01597, localized to multiple subcellular compartments including the nucleus, nucleolus, and plasma membrane, whereas an additional putative effector, PmEC03792, preferentially labelled both the nucleus and nucleolus. Intriguingly, one candidate effector, PmEC04573, consistently localized to the stroma of chloroplasts as well as stroma-containing tubules (stromules). Collectively, these data suggest that effector candidate proteins from P. maydis target diverse cellular organelles and could thus provide valuable insights into their putative functions, as well as host processes potentially manipulated by this fungal pathogen.
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Affiliation(s)
- Matthew Helm
- Crop Production and Pest Control Research Unit, U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), West Lafayette, IN 47907
| | - Raksha Singh
- Crop Production and Pest Control Research Unit, U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), West Lafayette, IN 47907
| | - Rachel Hiles
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907
| | - Namrata Jaiswal
- Crop Production and Pest Control Research Unit, U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), West Lafayette, IN 47907
| | - Ariana Myers
- Crop Production and Pest Control Research Unit, U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), West Lafayette, IN 47907
| | | | - Stephen B Goodwin
- Crop Production and Pest Control Research Unit, U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), West Lafayette, IN 47907
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15
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Matson MEH, Liang Q, Lonardi S, Judelson HS. Karyotype variation, spontaneous genome rearrangements affecting chemical insensitivity, and expression level polymorphisms in the plant pathogen Phytophthora infestans revealed using its first chromosome-scale assembly. PLoS Pathog 2022; 18:e1010869. [PMID: 36215336 PMCID: PMC9584435 DOI: 10.1371/journal.ppat.1010869] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 10/20/2022] [Accepted: 09/09/2022] [Indexed: 11/18/2022] Open
Abstract
Natural isolates of the potato and tomato pathogen Phytophthora infestans exhibit substantial variation in virulence, chemical sensitivity, ploidy, and other traits. A chromosome-scale assembly was developed to expand genomic resources for this oomyceteous microbe, and used to explore the basis of variation. Using PacBio and Illumina data, a long-range linking library, and an optical map, an assembly was created and coalesced into 15 pseudochromosomes spanning 219 Mb using SNP-based genetic linkage data. De novo gene prediction combined with transcript evidence identified 19,981 protein-coding genes, plus about eight thousand tRNA genes. The chromosomes were comprised of a mosaic of gene-rich and gene-sparse regions plus very long centromeres. Genes exhibited a biased distribution across chromosomes, especially members of families encoding RXLR and CRN effectors which clustered on certain chromosomes. Strikingly, half of F1 progeny of diploid parents were polyploid or aneuploid. Substantial expression level polymorphisms between strains were identified, much of which could be attributed to differences in chromosome dosage, transposable element insertions, and adjacency to repetitive DNA. QTL analysis identified a locus on the right arm of chromosome 3 governing sensitivity to the crop protection chemical metalaxyl. Strains heterozygous for resistance often experienced megabase-sized deletions of that part of the chromosome when cultured on metalaxyl, increasing resistance due to loss of the sensitive allele. This study sheds light on diverse phenomena affecting variation in P. infestans and relatives, helps explain the prevalence of polyploidy in natural populations, and provides a new foundation for biologic and genetic investigations.
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Affiliation(s)
- Michael E. H. Matson
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, United States of America
| | - Qihua Liang
- Department of Computer Science and Engineering, University of California, Riverside, California, United States of America
| | - Stefano Lonardi
- Department of Computer Science and Engineering, University of California, Riverside, California, United States of America
| | - Howard S. Judelson
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, United States of America
- * E-mail:
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16
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Todd JNA, Carreón-Anguiano KG, Islas-Flores I, Canto-Canché B. Microbial Effectors: Key Determinants in Plant Health and Disease. Microorganisms 2022; 10:1980. [PMID: 36296254 PMCID: PMC9610748 DOI: 10.3390/microorganisms10101980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/27/2022] [Accepted: 09/29/2022] [Indexed: 11/17/2022] Open
Abstract
Effectors are small, secreted molecules that alter host cell structure and function, thereby facilitating infection or triggering a defense response. Effectoromics studies have focused on effectors in plant-pathogen interactions, where their contributions to virulence are determined in the plant host, i.e., whether the effector induces resistance or susceptibility to plant disease. Effector molecules from plant pathogenic microorganisms such as fungi, oomycetes and bacteria are major disease determinants. Interestingly, the effectors of non-pathogenic plant organisms such as endophytes display similar functions but have different outcomes for plant health. Endophyte effectors commonly aid in the establishment of mutualistic interactions with the plant and contribute to plant health through the induction of systemic resistance against pathogens, while pathogenic effectors mainly debilitate the plant's immune response, resulting in the establishment of disease. Effectors of plant pathogens as well as plant endophytes are tools to be considered in effectoromics for the development of novel strategies for disease management. This review aims to present effectors in their roles as promotors of health or disease for the plant host.
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Affiliation(s)
- Jewel Nicole Anna Todd
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C., Calle 43 No. 130 x 32 y 34, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
| | - Karla Gisel Carreón-Anguiano
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C., Calle 43 No. 130 x 32 y 34, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
| | - Ignacio Islas-Flores
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, A.C., Calle 43 No. 130 x 32 y 34, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
| | - Blondy Canto-Canché
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C., Calle 43 No. 130 x 32 y 34, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
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17
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Wilson RA, McDowell JM. Recent advances in understanding of fungal and oomycete effectors. CURRENT OPINION IN PLANT BIOLOGY 2022; 68:102228. [PMID: 35605341 DOI: 10.1016/j.pbi.2022.102228] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 06/15/2023]
Abstract
Fungal and oomycete pathogens secrete complex arrays of proteins and small RNAs to interface with plant-host targets and manipulate plant regulatory networks to the microbes' advantage. Research on these important virulence factors has been accelerated by improved genome sequences, refined bioinformatic prediction tools, and exploitation of efficient platforms for understanding effector gene expression and function. Recent studies have validated the expectation that oomycetes and fungi target many of the same sectors in immune signaling networks, but the specific host plant targets and modes of action are diverse. Effector research has also contributed to deeper understanding of the mechanisms of effector-triggered immunity.
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Affiliation(s)
- Richard A Wilson
- Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - John M McDowell
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, USA.
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