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John E, Chau MQ, Hoang CV, Chandrasekharan N, Bhaskar C, Ma LS. Fungal Cell Wall-Associated Effectors: Sensing, Integration, Suppression, and Protection. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:196-210. [PMID: 37955547 DOI: 10.1094/mpmi-09-23-0142-fi] [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: 11/14/2023]
Abstract
The cell wall (CW) of plant-interacting fungi, as the direct interface with host plants, plays a crucial role in fungal development. A number of secreted proteins are directly associated with the fungal CW, either through covalent or non-covalent interactions, and serve a range of important functions. In the context of plant-fungal interactions many are important for fungal development in the host environment and may therefore be considered fungal CW-associated effectors (CWAEs). Key CWAE functions include integrating chemical/physical signals to direct hyphal growth, interfering with plant immunity, and providing protection against plant defenses. In recent years, a diverse range of mechanisms have been reported that underpin their roles, with some CWAEs harboring conserved motifs or functional domains, while others are reported to have novel features. As such, the current understanding regarding fungal CWAEs is systematically presented here from the perspective of their biological functions in plant-fungal interactions. An overview of the fungal CW architecture and the mechanisms by which proteins are secreted, modified, and incorporated into the CW is first presented to provide context for their biological roles. Some CWAE functions are reported across a broad range of pathosystems or symbiotic/mutualistic associations. Prominent are the chitin interacting-effectors that facilitate fungal CW modification, protection, or suppression of host immune responses. However, several alternative functions are now reported and are presented and discussed. CWAEs can play diverse roles, some possibly unique to fungal lineages and others conserved across a broad range of plant-interacting fungi. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Evan John
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Minh-Quang Chau
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Cuong V Hoang
- Centro de Biotecnología y Genómica de Plantas, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), Universidad Politécnica de Madrid (UPM), Campus de Montegancedo UPM, 28223 Pozuelo de Alarcón, Spain
| | | | - Chibbhi Bhaskar
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Lay-Sun Ma
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
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Lin YH, Xu MY, Hsu CC, Damei FA, Lee HC, Tsai WL, Hoang CV, Chiang YR, Ma LS. Ustilago maydis PR-1-like protein has evolved two distinct domains for dual virulence activities. Nat Commun 2023; 14:5755. [PMID: 37716995 PMCID: PMC10505147 DOI: 10.1038/s41467-023-41459-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 09/05/2023] [Indexed: 09/18/2023] Open
Abstract
The diversification of effector function, driven by a co-evolutionary arms race, enables pathogens to establish compatible interactions with hosts. Structurally conserved plant pathogenesis-related PR-1 and PR-1-like (PR-1L) proteins are involved in plant defense and fungal virulence, respectively. It is unclear how fungal PR-1L counters plant defense. Here, we show that Ustilago maydis UmPR-1La and yeast ScPRY1, with conserved phenolic resistance functions, are Ser/Thr-rich region mediated cell-surface localization proteins. However, UmPR-1La has gained specialized activity in sensing phenolics and eliciting hyphal-like formation to guide fungal growth in plants. Additionally, U. maydis hijacks maize cathepsin B-like 3 (CatB3) to release functional CAPE-like peptides by cleaving UmPR-1La's conserved CNYD motif, subverting plant CAPE-primed immunity and promoting fungal virulence. Surprisingly, CatB3 avoids cleavage of plant PR-1s, despite the presence of the same conserved CNYD motif. Our work highlights that UmPR-1La has acquired additional dual roles to suppress plant defense and sustain the infection process of fungal pathogens.
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Affiliation(s)
- Yu-Han Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 115201, Taiwan
| | - Meng-Yun Xu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 115201, Taiwan
| | - Chuan-Chih Hsu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 115201, Taiwan
| | | | - Hui-Chun Lee
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 115201, Taiwan
| | - Wei-Lun Tsai
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 115201, Taiwan
| | - Cuong V Hoang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 115201, Taiwan
| | - Yin-Ru Chiang
- Biodiversity Research Center, Academia Sinica, Taipei, 115201, Taiwan
| | - Lay-Sun Ma
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 115201, Taiwan.
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Liu JJ, Sniezko RA, Zamany A, Williams H, Omendja K, Kegley A, Savin DP. Comparative Transcriptomics and RNA-Seq-Based Bulked Segregant Analysis Reveals Genomic Basis Underlying Cronartium ribicola vcr2 Virulence. Front Microbiol 2021; 12:602812. [PMID: 33776951 PMCID: PMC7990074 DOI: 10.3389/fmicb.2021.602812] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 02/01/2021] [Indexed: 12/25/2022] Open
Abstract
Breeding programs of five-needle pines have documented both major gene resistance (MGR) and quantitative disease resistance (QDR) to Cronartium ribicola (Cri), a non-native, invasive fungal pathogen causing white pine blister rust (WPBR). WPBR is one of the most deadly forest diseases in North America. However, Cri virulent pathotypes have evolved and can successfully infect and kill trees carrying resistance (R) genes, including vcr2 that overcomes MGR conferred by the western white pine (WWP, Pinus monticola) R gene (Cr2). In the absence of a reference genome, the present study generated a vcr2 reference transcriptome, consisting of about 20,000 transcripts with 1,014 being predicted to encode secreted proteins (SPs). Comparative profiling of transcriptomes and secretomes revealed vcr2 was significantly enriched for several gene ontology (GO) terms relating to oxidation-reduction processes and detoxification, suggesting that multiple molecular mechanisms contribute to pathogenicity of the vcr2 pathotype for its overcoming Cr2. RNA-seq-based bulked segregant analysis (BSR-Seq) revealed genome-wide DNA variations, including about 65,617 single nucleotide polymorphism (SNP) loci in 7,749 polymorphic genes shared by vcr2 and avirulent (Avcr2) pathotypes. An examination of the distribution of minor allele frequency (MAF) uncovered a high level of genomic divergence between vcr2 and Avcr2 pathotypes. By integration of extreme-phenotypic genome-wide association (XP-GWAS) analysis and allele frequency directional difference (AFDD) mapping, we identified a set of vcr2-associated SNPs within functional genes, involved in fungal virulence and other molecular functions. These included six SPs that were top candidate effectors with putative activities of reticuline oxidase, proteins with common in several fungal extracellular membrane (CFEM) domain or ferritin-like domain, polysaccharide lyase, rds1p-like stress responsive protein, and two Cri-specific proteins without annotation. Candidate effectors and vcr2-associated genes provide valuable resources for further deciphering molecular mechanisms of virulence and pathogenicity by functional analysis and the subsequent development of diagnostic tools for monitoring the virulence landscape in the WPBR pathosystems.
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Affiliation(s)
- Jun-Jun Liu
- Canadian Forest Service, Natural Resources Canada, Victoria, BC, Canada
| | - Richard A Sniezko
- USDA Forest Service, Dorena Genetic Resource Center, Cottage Grove, OR, United States
| | - Arezoo Zamany
- Canadian Forest Service, Natural Resources Canada, Victoria, BC, Canada
| | - Holly Williams
- Canadian Forest Service, Natural Resources Canada, Victoria, BC, Canada
| | - Kangakola Omendja
- Canadian Forest Service, Natural Resources Canada, Victoria, BC, Canada
| | - Angelia Kegley
- USDA Forest Service, Dorena Genetic Resource Center, Cottage Grove, OR, United States
| | - Douglas P Savin
- USDA Forest Service, Dorena Genetic Resource Center, Cottage Grove, OR, United States
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Han Z, Xiong D, Xu Z, Liu T, Tian C. The Cytospora chrysosperma Virulence Effector CcCAP1 Mainly Localizes to the Plant Nucleus To Suppress Plant Immune Responses. mSphere 2021; 6:e00883-20. [PMID: 33627507 PMCID: PMC8544888 DOI: 10.1128/msphere.00883-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 02/01/2021] [Indexed: 01/07/2023] Open
Abstract
Canker disease is caused by the fungus Cytospora chrysosperma and damages a wide range of woody plants, causing major losses to crops and native plants. Plant pathogens secrete virulence-related effectors into host cells during infection to regulate plant immunity and promote colonization. However, the functions of C. chrysosperma effectors remain largely unknown. In this study, we used Agrobacterium tumefaciens-mediated transient expression system in Nicotiana benthamiana and confocal microscopy to investigate the immunoregulation roles and subcellular localization of CcCAP1, a virulence-related effector identified in C. chrysosperma CcCAP1 was significantly induced in the early stages of infection and contains cysteine-rich secretory proteins, antigen 5, and pathogenesis-related 1 proteins (CAP) superfamily domain with four cysteines. CcCAP1 suppressed the programmed cell death triggered by Bcl-2-associated X protein (BAX) and the elicitin infestin1 (INF1) in transient expression assays with Nicotiana benthamiana The CAP superfamily domain was sufficient for its cell death-inhibiting activity and three of the four cysteines in the CAP superfamily domain were indispensable for its activity. Pathogen challenge assays in N. benthamiana demonstrated that transient expression of CcCAP1 promoted Botrytis cinerea infection and restricted reactive oxygen species accumulation, callose deposition, and defense-related gene expression. In addition, expression of green fluorescent protein-labeled CcCAP1 in N. benthamiana showed that it localized to both the plant nucleus and the cytoplasm, but the nuclear localization was essential for its full immune inhibiting activity. These results suggest that this virulence-related effector of C. chrysosperma modulates plant immunity and functions mainly via its nuclear localization and the CAP domain.IMPORTANCE The data presented in this study provide a key resource for understanding the biology and molecular basis of necrotrophic pathogen responses to Nicotiana benthamiana resistance utilizing effector proteins, and CcCAP1 may be used in future studies to understand effector-triggered susceptibility processes in the Cytospora chrysosperma-poplar interaction system.
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Affiliation(s)
- Zhu Han
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Dianguang Xiong
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Zhiye Xu
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Tingli Liu
- Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Chengming Tian
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
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