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Molinari C, Talbot NJ. A Basic Guide to the Growth and Manipulation of the Blast Fungus,
Magnaporthe oryzae. Curr Protoc 2022; 2:e523. [PMID: 35997707 PMCID: PMC9542439 DOI: 10.1002/cpz1.523] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The blast fungus, Magnaporthe oryzae, is a devastating plant pathogen that threatens global food security. The social and economic importance of blast disease has contributed to this filamentous fungus becoming a model organism for the study of host‐pathogen interactions. Availability of the complete genome sequences of many strains of the pathogen, as well as rice and wheat cultivars, coupled with the tractability of M. oryzae to classical and molecular genetic manipulation have contributed to its widespread study. Although M. oryzae has been extensively investigated for the past two decades, procedures for storing, maintaining, and manipulating the blast fungus in the laboratory had not been compiled and updated. As a consequence, there is considerable disparity in how the fungus is stored and manipulated between studies. In this article, we present a collection of protocols providing clear explanations of how to preserve filter stocks of M. oryzae; how to grow the fungus in both liquid and solid media; how to extract genomic DNA from fungal mycelium; how to induce appressorium formation on coverslips for visualization and tissue collection; and how to perform two distinct types of plant infection assay for virulence assessment. By sharing our most used laboratory procedures, we aim to address some of the knowledge gaps in current M. oryzae protocols and contribute to uniformity and robustness in studies by the Magnaporthe research community. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Storage of M. oryzae strains Basic Protocol 2: Revival and regular maintenance of M. oryzae cultures in solid medium Alternate Protocol 1: Regular maintenance of M. oryzae cultures in liquid medium Basic Protocol 3: Genomic DNA extraction from M. oryzae mycelium Alternate Protocol 2: Quick DNA extraction from M. oryzae mycelium Basic Protocol 4: M. oryzae induction of appressorium development on glass coverslips for microscopy Alternate Protocol 3: M. oryzae induction of appressorium development on glass coverslips for tissue collection Basic Protocol 5: M. oryzae rice infection assay through spray inoculation Alternate Protocol 4: M. oryzae leaf‐drop plant infection assay
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Affiliation(s)
- Camilla Molinari
- The Sainsbury Laboratory, Norwich Research Park University of East Anglia Norwich United Kingdom
| | - Nicholas J. Talbot
- The Sainsbury Laboratory, Norwich Research Park University of East Anglia Norwich United Kingdom
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2
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Ebbole DJ, Chen M, Zhong Z, Farmer N, Zheng W, Han Y, Lu G, Wang Z. Evolution and Regulation of a Large Effector Family of Pyricularia oryzae. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:255-269. [PMID: 33211639 DOI: 10.1094/mpmi-07-20-0210-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Plant pathogen effectors play important roles in parasitism, including countering plant immunity. However, investigations of the emergence and diversification of fungal effectors across host-adapted populations has been limited. We previously identified a gene encoding a suppressor of plant cell death in Pyricularia oryzae (syn. Magnaporthe oryzae). Here, we report the gene is one of a 21-member gene family and we characterize sequence diversity in different populations. Within the rice pathogen population, nucleotide diversity is low, however; the majority of gene family members display presence-absence polymorphism or other null alleles. Gene family allelic diversity is greater between host-adapted populations and, thus, we named them host-adapted genes (HAGs). Multiple copies of HAGs were found in some genome assemblies and sequence divergence between the alleles in two cases suggested they were the result of repeat-induced point mutagenesis. Transfer of family members between populations and novel HAG haplotypes resulting from apparent recombination were observed. HAG family transcripts were induced in planta and a subset of HAGs are dependent on a key regulator of pathogenesis, PMK1. We also found differential intron splicing for some HAGs that would prevent ex planta protein expression. For some genes, spliced transcript was expressed in antiphase with an overlapping antisense transcript. Characterization of HAG expression patterns and allelic diversity reveal novel mechanisms for HAG regulation and mechanisms generating sequence diversity and novel allele combinations. This evidence of strong in planta-specific expression and selection operating on the HAG family is suggestive of a role in parasitism.[Formula: see text] Copyright © 2021 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)
- Daniel J Ebbole
- Department of Plant Pathology & Microbiology, Texas A&M University, College Station, TX, 77843, U.S.A
| | - Meilian Chen
- Department of Plant Pathology & Microbiology, Texas A&M University, College Station, TX, 77843, U.S.A
- Institute of Oceanography, Minjiang University, Fuzhou, 350108, China
| | - Zhenhui Zhong
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fujian 350002, China
| | - Nicholas Farmer
- Department of Plant Pathology & Microbiology, Texas A&M University, College Station, TX, 77843, U.S.A
| | - Wenhui Zheng
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fujian 350002, China
| | - Yijuan Han
- Institute of Oceanography, Minjiang University, Fuzhou, 350108, China
| | - Guodong Lu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fujian 350002, China
| | - Zonghua Wang
- Institute of Oceanography, Minjiang University, Fuzhou, 350108, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fujian 350002, China
- Fujian Universities Key Laboratory of Plant-Microbe Interactions, College of Life Science, Fujian Agriculture and Forestry University, Fujian 350002, China
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3
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Dulal N, Rogers AM, Proko R, Bieger BD, Liyanage R, Krishnamurthi VR, Wang Y, Egan MJ. Turgor-dependent and coronin-mediated F-actin dynamics drive septin disc-to-ring remodeling in the blast fungus Magnaporthe oryzae. J Cell Sci 2021; 134:jcs.251298. [PMID: 33414165 DOI: 10.1242/jcs.251298] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 12/16/2020] [Indexed: 12/16/2022] Open
Abstract
The fungus Magnaporthe oryzae uses a specialized pressure-generating infection cell called an appressorium to break into rice leaves and initiate disease. Appressorium functionality is dependent on the formation of a cortical septin ring during its morphogenesis, but precisely how this structure assembles is unclear. Here, we show that F-actin rings are recruited to the circumference of incipient septin disc-like structures in a pressure-dependent manner, and that this is necessary for their contraction and remodeling into rings. We demonstrate that the structural integrity of these incipient septin discs requires both an intact F-actin and microtubule cytoskeleton and provide fundamental new insight into their functional organization within the appressorium. Lastly, using proximity-dependent labeling, we identify the actin modulator coronin as a septin-proximal protein and show that F-actin-mediated septin disc-to-ring remodeling is perturbed in the genetic absence of coronin. Taken together, our findings provide new insight into the dynamic remodeling of infection-specific higher-order septin structures in a globally significant fungal plant pathogen.
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Affiliation(s)
- Nawaraj Dulal
- Department of Entomology and Plant Pathology, University of Arkansas Systems Division of Agriculture, Fayetteville, AR 72701, USA
| | - Audra Mae Rogers
- Department of Entomology and Plant Pathology, University of Arkansas Systems Division of Agriculture, Fayetteville, AR 72701, USA
| | - Rinalda Proko
- Department of Entomology and Plant Pathology, University of Arkansas Systems Division of Agriculture, Fayetteville, AR 72701, USA.,Cell and Molecular Biology graduate program, University of Arkansas, Fayetteville, AR 72701, USA
| | - Baronger Dowell Bieger
- Department of Entomology and Plant Pathology, University of Arkansas Systems Division of Agriculture, Fayetteville, AR 72701, USA.,Cell and Molecular Biology graduate program, University of Arkansas, Fayetteville, AR 72701, USA
| | - Rohana Liyanage
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | | | - Yong Wang
- Cell and Molecular Biology graduate program, University of Arkansas, Fayetteville, AR 72701, USA.,Department of Physics, University of Arkansas, Fayetteville, AR 72701, USA.,Microelectronics-Photonics graduate program, University of Arkansas, Fayetteville, AR 72701, USA
| | - Martin John Egan
- Department of Entomology and Plant Pathology, University of Arkansas Systems Division of Agriculture, Fayetteville, AR 72701, USA .,Cell and Molecular Biology graduate program, University of Arkansas, Fayetteville, AR 72701, USA
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Abstract
Rice blast disease is both the most explosive and potentially damaging disease of the world's rice (Oryza sativa) crop and a model system for research on the molecular mechanisms that fungi use to cause plant disease. The blast fungus, Magnaporthe oryzae, is highly evolved to sense when it is on a leaf surface; to develop a pressurized cell, the appressorium, to punch through the leaf cuticle; and then to hijack living rice cells to assist it in causing disease. Host specificity, determining which plants particular fungal strains can infect, is also an important topic for research. The blast fungus is a moving target, quickly overcoming rice resistance genes we deploy to control it, and recently emerging to cause devastating disease on an entirely new cereal crop, wheat. M. oryzae is highly adaptable, with multiple examples of genetic instability at certain gene loci and in certain genomic regions. Understanding the biology of the fungus in the field, and its potential for genetic and genome variability, is key to keep it from adapting to life in the research laboratory and losing relevance to the significant impact it has on global food security.
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Affiliation(s)
- Barbara Valent
- Department of Plant Pathology, Kansas State University, Manhattan, KS, USA.
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5
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Rogers AM, Egan MJ. Autophagy machinery promotes the chaperone-mediated formation and compartmentalization of protein aggregates during appressorium development by the rice blast fungus. Mol Biol Cell 2020; 31:2298-2305. [PMID: 32816646 PMCID: PMC7851963 DOI: 10.1091/mbc.e20-01-0068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The chaperone-mediated sequestration of misfolded proteins into specialized quality control compartments represents an important strategy for maintaining protein homeostasis in response to stress. However, precisely how this process is controlled in time and subcellular space and integrated with the cell's protein refolding and degradation pathways remains unclear. We set out to understand how aggregated proteins are managed during infection-related development by a globally devastating plant pathogenic fungus and to determine how impaired protein quality control impacts cellular differentiation and pathogenesis in this system. Here we show that in the absence of Hsp104 disaggregase activity, aggregated proteins are spatially sequestered into quality control compartments within conidia, but not within terminally differentiated infection cells, and thus spatial protein quality control is cell type–dependent. We demonstrate that impaired aggregate resolution results in a short-term developmental penalty but has no significant impact upon appressorium function. Finally, we show that, somewhat unexpectedly, the autophagy machinery is necessary for the normal formation and compartmentalization of protein aggregates. Taken together, our findings provide important new insight into spatial protein quality control during the process of terminal cellular differentiation by a globally important model eukaryote and reveal a new level of interplay between major proteostasis pathways.
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Affiliation(s)
- Audra Mae Rogers
- Department of Entomology and Plant Pathology, Division of Agriculture, University of Arkansas Systems, Fayetteville, AR 72701
| | - Martin John Egan
- Department of Entomology and Plant Pathology, Division of Agriculture, University of Arkansas Systems, Fayetteville, AR 72701.,Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701
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Wang JY, Li L, Chai RY, Qiu HP, Zhang Z, Wang YL, Liu XH, Lin FC, Sun GC. Pex13 and Pex14, the key components of the peroxisomal docking complex, are required for peroxisome formation, host infection and pathogenicity-related morphogenesis in Magnaporthe oryzae. Virulence 2020; 10:292-314. [PMID: 30905264 PMCID: PMC6527019 DOI: 10.1080/21505594.2019.1598172] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Peroxisomes are ubiquitous organelles in eukaryotic cells that fulfill multiple important metabolisms. Pex13 and Pex14 are key components of the peroxisomal docking complex in yeasts and mammals. In the present work, we functionally characterized the homologues of Pex13 and Pex14 (Mopex13 and Mopex14) in the rice blast fungus Magnaporthe oryzae. Mopex13 and Mopex14 were peroxisomal membrane distributed and were both essential for the maintenance of Mopex14/17 on the peroxisomal membrane. Mopex13 and Mopex14 interacted with each other, and with Mopex14/17 and peroxisomal matrix protein receptors. Disruption of Mopex13 and Mopex14 resulted in a cytoplasmic distribution of peroxisomal matrix proteins and the Woronin body protein Hex1. In the ultrastructure of Δmopex13 and Δmopex14 cells, peroxisomes were detected on fewer occasions, and the Woronin bodies and related structures were dramatically affected. The Δmopex13 and Δmopex14 mutants were reduced in vegetative growth, conidial generation and mycelial melanization, in addition, Δmopex13 showed reduced conidial germination and appressorial formation and abnomal appressorial morphology. Both Δmopex13 and Δmopex14 were deficient in appressorial turgor and nonpathogenic to their hosts. The infection failures in Δmopex13 and Δmopex14 were also due to their reduced ability to degrade fatty acids and to endure reactive oxygen species and cell wall-disrupting compounds. Additionally, Mopex13 and Mopex14 were required for the sexual reproduction of the fungus. These data indicate that Mopex13 and Mopex14, as key components of the peroxisomal docking complex, are indispensable for peroxisomal biogenesis, fungal development and pathogenicity in the rice blast fungus.
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Affiliation(s)
- Jiao-Yu Wang
- a State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology , Zhejiang Academy of Agricultural Sciences , Hangzhou , China
| | - Ling Li
- a State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology , Zhejiang Academy of Agricultural Sciences , Hangzhou , China.,b The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, School of Agricultural and Food Sciences , Zhejiang Agriculture and Forest University , Hangzhou , China
| | - Rong-Yao Chai
- a State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology , Zhejiang Academy of Agricultural Sciences , Hangzhou , China
| | - Hai-Ping Qiu
- a State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology , Zhejiang Academy of Agricultural Sciences , Hangzhou , China
| | - Zhen Zhang
- a State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology , Zhejiang Academy of Agricultural Sciences , Hangzhou , China
| | - Yan-Li Wang
- a State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology , Zhejiang Academy of Agricultural Sciences , Hangzhou , China
| | - Xiao-Hong Liu
- c State Key Laboratory for Rice Biology, Biotechnology Institute , Zhejiang University , Hangzhou , China
| | - Fu-Cheng Lin
- c State Key Laboratory for Rice Biology, Biotechnology Institute , Zhejiang University , Hangzhou , China
| | - Guo-Chang Sun
- a State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology , Zhejiang Academy of Agricultural Sciences , Hangzhou , China
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7
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Wang ZQ, Meng FZ, Zhang MM, Yin LF, Yin WX, Lin Y, Hsiang T, Peng YL, Wang ZH, Luo CX. A Putative Zn 2Cys 6 Transcription Factor Is Associated With Isoprothiolane Resistance in Magnaporthe oryzae. Front Microbiol 2018; 9:2608. [PMID: 30429837 PMCID: PMC6220061 DOI: 10.3389/fmicb.2018.02608] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 10/12/2018] [Indexed: 12/18/2022] Open
Abstract
Isoprothiolane (IPT), a systemic fungicide, has been applied to control rice blast since the 1970s. Although resistance to IPT has been observed, the mechanism of resistance still has not been fully elucidated. In this study, nucleotide polymorphisms were detected between two IPT-resistant mutants generated in the lab, and their parental wild type isolates using a whole-genome sequencing approach. In the genomes of the two resistant mutants, single point mutations were identified in a gene encoding a Zn2Cys6 transcription factor-like protein. Notably, either knocking out the gene or replacing the wild type allele with the mutant allele (R343W) in a wild type isolate resulted in resistance to IPT, indicating that the gene is associated with IPT resistance, and thus was designated as MoIRR (Magnaporthe oryzae isoprothiolane resistance related). Along with point mutations R343W in mutant 1a_mut, and R345C in 1c_mut, a 16 bp insertion in 6c_mut was also located in the Fungal_TF_MHR domain of MoIRR, revealing that this domain may be the core element for IPT resistance. In addition, IPT-resistant mutants and transformants showed cross-resistance with iprobenfos (IBP), which was consistent with previous observations. These results indicated that MoIRR is strongly connected to resistance to choline biosynthesis inhibitor (CBI), and further work should focus on investigating downstream effects of MoIRR.
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Affiliation(s)
- Zuo-Qian Wang
- Department of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Fan-Zhu Meng
- Department of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Ming-Ming Zhang
- Department of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Liang-Fen Yin
- Department of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
- The Key Lab of Crop Disease Monitoring & Safety Control in Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Wei-Xiao Yin
- Department of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
- The Key Lab of Crop Disease Monitoring & Safety Control in Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Yang Lin
- Department of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
- The Key Lab of Crop Disease Monitoring & Safety Control in Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Tom Hsiang
- School of Environmental Sciences, University of Guelph, Guelph, ON, Canada
| | - You-Liang Peng
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Zong-Hua Wang
- College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Chao-Xi Luo
- Department of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
- The Key Lab of Crop Disease Monitoring & Safety Control in Hubei Province, Huazhong Agricultural University, Wuhan, China
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8
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Newton AC, Osbourn AE, Caten CE. Heterokaryosis and vegetative incompatibility in Stagonospora nodorum. Mycologia 2018. [DOI: 10.1080/00275514.1998.12026901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Adrian C. Newton
- School of Biological Sciences, The University of Birmingham, PO Box 363, Birmingham B15 2TT, UK
| | - Anne E. Osbourn
- School of Biological Sciences, The University of Birmingham, PO Box 363, Birmingham B15 2TT, UK
| | - Christopher E. Caten
- School of Biological Sciences, The University of Birmingham, PO Box 363, Birmingham B15 2TT, UK
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9
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Harp TL, Correll JC. Recovery and characterization of spontaneous, selenate-resistant mutants ofMagnaporthe grisea, the rice blast pathogen. Mycologia 2018. [DOI: 10.1080/00275514.1998.12026992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Tyler L. Harp
- Department of Plant Pathology, University of Arkansas, 217 Plant Science, Fayetteville, Arkansas 72701
| | - James C. Correll
- Department of Plant Pathology, University of Arkansas, 217 Plant Science, Fayetteville, Arkansas 72701
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10
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Zhong Z, Chen M, Lin L, Han Y, Bao J, Tang W, Lin L, Lin Y, Somai R, Lu L, Zhang W, Chen J, Hong Y, Chen X, Wang B, Shen WC, Lu G, Norvienyeku J, Ebbole DJ, Wang Z. Population genomic analysis of the rice blast fungus reveals specific events associated with expansion of three main clades. ISME JOURNAL 2018; 12:1867-1878. [PMID: 29568114 PMCID: PMC6051997 DOI: 10.1038/s41396-018-0100-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 02/10/2018] [Accepted: 02/20/2018] [Indexed: 12/30/2022]
Abstract
We examined the genomes of 100 isolates of Magnaporthe oryzae (Pyricularia oryzae), the causal agent of rice blast disease. We grouped current field populations of M. oryzae into three major globally distributed groups. A genetically diverse group, clade 1, which may represent a group of closely related lineages, contains isolates of both mating types. Two well-separated clades, clades 2 and 3, appear to have arisen as clonal lineages distinct from the genetically diverse clade. Examination of genes involved in mating pathways identified clade-specific diversification of several genes with orthologs involved in mating behavior in other fungi. All isolates within each clonal lineage are of the same mating type. Clade 2 is distinguished by a unique deletion allele of a gene encoding a small cysteine-rich protein that we determined to be a virulence factor. Clade 3 isolates have a small deletion within the MFA2 pheromone precursor gene, and this allele is shared with an unusual group of isolates we placed within clade 1 that contain AVR1-CO39 alleles. These markers could be used for rapid screening of isolates and suggest specific events in evolution that shaped these populations. Our findings are consistent with the view that M. oryzae populations in Asia generate diversity through recombination and may have served as the source of the clades 2 and 3 isolates that comprise a large fraction of the global population.
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Affiliation(s)
- Zhenhui Zhong
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Meilian Chen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Lianyu Lin
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Yijuan Han
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Jiandong Bao
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Wei Tang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Lili Lin
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Yahong Lin
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Rewish Somai
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Lin Lu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Wenjing Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Jian Chen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Yonghe Hong
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xiaofeng Chen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Baohua Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Wei-Chiang Shen
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, Republic of China.
| | - Guodong Lu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Justice Norvienyeku
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. .,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
| | - Daniel J Ebbole
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. .,Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, USA.
| | - Zonghua Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. .,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. .,Institute of Ocean Science, Minjiang University, Fuzhou, 350108, China.
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Pagliaccia D, Urak RZ, Wong F, Douhan LI, Greer CA, Vidalakis G, Douhan GW. Genetic Structure of the Rice Blast Pathogen (Magnaporthe oryzae) over a Decade in North Central California Rice Fields. MICROBIAL ECOLOGY 2018; 75:310-317. [PMID: 28755027 PMCID: PMC5742603 DOI: 10.1007/s00248-017-1029-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 06/28/2017] [Indexed: 06/07/2023]
Abstract
Rice blast, caused by the ascomycete Magnaporthe oryzae, is one of the most destructive rice diseases worldwide. Even though the disease has been present in California since 1996, there is no data for the pathogen population biology in the state. Using amplified fragment length polymorphisms and mating-type markers, the M. oryzae population diversity was investigated using isolates collected when the disease was first established in California and isolates collected a decade later. While in the 1990 samples, a single multilocus genotype (MLG) was identified (MLG1), over a decade later, we found 14 additional MLGs in the 2000 isolates. Some of these MLGs were found to infect the only rice blast-resistant cultivar (M-208) available for commercial production in California. The same samples also had a significant decrease of MLG1. MLG1 was found infecting the resistant rice cultivar M-208 on one occasion whereas MLG7 was the most common genotype infecting the M-208. MLG7 was identified in the 2000 samples, and it was not present in the M. oryzae population a decade earlier. Our results demonstrate a significant increase in genotypic diversity over time with no evidence of sexual reproduction and suggest a recent introduction of new virulent race(s) of the pathogen. In addition, our data could provide information regarding the durability of the Pi-z resistance gene of the M-208. This information will be critical to plant breeders in developing strategies for deployment of other rice blast resistance genes/cultivars in the future.
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Affiliation(s)
- Deborah Pagliaccia
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA, 92521, USA.
- Department of Botany and Plant Sciences, University of California, Riverside, CA, USA.
| | - Ryan Z Urak
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA, 92521, USA
| | - Frank Wong
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA, 92521, USA
- Bayer's Environmental Health Division, Bayer, Durham, NC, USA
| | - LeAnn I Douhan
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA, 92521, USA
- Val Verde Unified School District, Perris, CA, USA
| | - Christopher A Greer
- Cooperative Extension, University of California, Sutter-Yuba, Yuba City, CA, 95991, USA
| | - Georgios Vidalakis
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA, 92521, USA
| | - Greg W Douhan
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA, 92521, USA
- Cooperative Extension Tulare County, Tulare, CA, USA
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Li L, Wang J, Chen H, Chai R, Zhang Z, Mao X, Qiu H, Jiang H, Wang Y, Sun G. Pex14/17, a filamentous fungus-specific peroxin, is required for the import of peroxisomal matrix proteins and full virulence of Magnaporthe oryzae. MOLECULAR PLANT PATHOLOGY 2017; 18:1238-1252. [PMID: 27571711 PMCID: PMC6638247 DOI: 10.1111/mpp.12487] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/11/2016] [Accepted: 08/28/2016] [Indexed: 05/27/2023]
Abstract
Peroxisomes are ubiquitous organelles in eukaryotic cells that fulfil a variety of biochemical functions. The biogenesis of peroxisomes requires a variety of proteins, named peroxins, which are encoded by PEX genes. Pex14/17 is a putative recently identified peroxin, specifically present in filamentous fungal species. Its function in peroxisomal biogenesis is still obscure and its roles in fungal pathogenicity have not yet been documented. Here, we demonstrate the contributions of Pex14/17 in the rice blast fungus Magnaporthe oryzae (Mopex14/17) to peroxisomal biogenesis and fungal pathogenicity by targeting gene replacement strategies. Mopex14/17 has properties of both Pex14 and Pex17 with regard to its protein sequence. Mopex14/17 is distributed at the peroxisomal membrane and is essential for efficient peroxisomal targeting of proteins containing peroxisomal targeting signal 1. MoPEX19 deletion leads to the cytoplasmic distribution of Mopex14/17, indicating that the peroxisomal import of Pex14/17 is dependent on Pex19. The knockout mutants of MoPEX14/17 show reduced fatty acid utilization, reactive oxygen species (ROS) degradation and cell wall integrity. Moreover, Δmopex14/17 mutants show delayed conidial generation and appressorial formation, and a reduction in appressorial turgor accumulation and penetration ability in host plants. These defects result in a significant reduction in the virulence of the mutant. These data indicate that MoPEX14/17 plays a crucial role in peroxisome biogenesis and contributes to fungal development and pathogenicity.
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Affiliation(s)
- Ling Li
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease ControlInstitute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural SciencesHangzhou310021China
- School of Agricultural and Food SciencesZhejiang Agriculture and Forest UniversityHangzhou311300China
| | - Jiaoyu Wang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease ControlInstitute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural SciencesHangzhou310021China
| | - Haili Chen
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease ControlInstitute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural SciencesHangzhou310021China
| | - Rongyao Chai
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease ControlInstitute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural SciencesHangzhou310021China
| | - Zhen Zhang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease ControlInstitute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural SciencesHangzhou310021China
| | - Xueqin Mao
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease ControlInstitute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural SciencesHangzhou310021China
| | - Haiping Qiu
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease ControlInstitute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural SciencesHangzhou310021China
| | - Hua Jiang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease ControlInstitute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural SciencesHangzhou310021China
| | - Yanli Wang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease ControlInstitute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural SciencesHangzhou310021China
| | - Guochang Sun
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease ControlInstitute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural SciencesHangzhou310021China
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Matheis S, Yemelin A, Scheps D, Andresen K, Jacob S, Thines E, Foster A. Functions of the Magnaporthe oryzae Flb3p and Flb4p transcription factors in the regulation of conidiation. Microbiol Res 2017; 196:106-117. [DOI: 10.1016/j.micres.2016.12.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 12/23/2016] [Accepted: 12/27/2016] [Indexed: 11/26/2022]
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14
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Wang J, Li L, Zhang Z, Qiu H, Li D, Fang Y, Jiang H, Chai RY, Mao X, Wang Y, Sun G. One of Three Pex11 Family Members Is Required for Peroxisomal Proliferation and Full Virulence of the Rice Blast Fungus Magnaporthe oryzae. PLoS One 2015. [PMID: 26218097 PMCID: PMC4517885 DOI: 10.1371/journal.pone.0134249] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Peroxisomes play important roles in metabolisms of eukaryotes and infection of plant fungal pathogens. These organelles proliferate by de novo formation or division in response to environmental stimulation. Although the assembly of peroxisomes was documented in fungal pathogens, their division and its relationship to pathogenicity remain obscure. In present work, we analyzed the roles of three Pex11 family members in peroxisomal division and pathogenicity of the rice blast fungus Magnaporthe oryzae. Deletion of MoPEX11A led to fewer but enlarged peroxisomes, and impaired the separation of Woronin bodies from peroxisomes, while deletion of MoPEX11B or MoPEX11C put no evident impacts to peroxisomal profiles. MoPEX11A mutant exhibited typical peroxisome related defects, delayed conidial germination and appressoria formation, and decreased appressorial turgor and host penetration. As a result, the virulence of MoPEX11A mutant was greatly reduced. Deletion of MoPEX11B and MoPEX11C did not alter the virulence of the fungus. Further, double or triple deletions of the three genes were unable to enhance the virulence decrease in MoPEX11A mutant. Our data indicated that MoPEX11A is the main factor modulating peroxisomal division and is required for full virulence of the fungus.
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Affiliation(s)
- Jiaoyu Wang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Ling Li
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
- School of Agricultural and Food Sciences, Zhejiang Agriculture and Forest University, Hangzhou, China
| | - Zhen Zhang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Haiping Qiu
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Dongmei Li
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Yuan Fang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China
| | - Hua Jiang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Rong Yao Chai
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Xueqin Mao
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Yanli Wang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Guochang Sun
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
- * E-mail:
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15
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Avila-Adame C. Transmission of the G143A QoI-resistance point mutation through anastomosis in Magnaporthe grisea. PEST MANAGEMENT SCIENCE 2014; 70:1918-823. [PMID: 24652760 DOI: 10.1002/ps.3758] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 01/21/2014] [Accepted: 02/02/2014] [Indexed: 06/03/2023]
Abstract
BACKGROUND Soon after the introduction of Qo inhibitor fungicides in 1996, the point mutation leading to the amino acid exchange glycine to alanine at the 143 position of the mitochondrial cytochrome b gene was identified as the main cause of resistance. The present study describes the role of anastomosis in the transmission of the G143A mutation in Magnaporthe grisea. RESULTS Two M. grisea mutants were co-cultivated on oatmeal agar and also co-inoculated on barley leaves. The mutants differed by the presence of the G143A mutation in one isolate and a disrupted AOX gene by insertion of a hygromycin gene in the other (M-145). Specific resistant (r) or sensitive (s) phenotypes of 409 monosporic cultures were determined on media amended with either hygromycin (H) or azoxystrobin (S) plus SHAM. The phenotypes identified reflected not only the phenotypes of mutants M-145 and G143A but also the wild-type parent phenotype HsSs and a new HrSr isolate. CONCLUSION Identification of the M. grisea phenotypes HrSr and HsSs suggests that anastomosis occurred during co-cultivation and co-inoculation of the mutants M-145 and G143A, allowing the transfer of the G143A point mutation from the QoI-resistant isolate to the susceptible isolate.
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Bock CH, Wood BW, Stevenson KL, Arias RS. Genetic Diversity and Population Structure of Fusicladium effusum on Pecan in the United States. PLANT DISEASE 2014; 98:916-923. [PMID: 30708843 DOI: 10.1094/pdis-12-13-1229-re] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Fusicladium effusum causes pecan scab, which is the most destructive disease of pecan orchards in the United States. Conidia of the pathogen are spread by rain splash and wind. The fungus is pathogenically diverse; yet there is no information on its genetic diversity or population genetics. Universally primed polymerase chain reaction (UP-PCR) was used to investigate the genetic diversity and population structure on a hierarchical sample of 194 isolates collected from 11 orchard locations from Florida to Texas, consisting of three to four isolates from each of five to six trees at each location. Genetic variation was high throughout the region, with all but nine of the multilocus haplotypes being unique. Nei's average gene diversity ranged from 0.083 for a population from Mississippi to 0.160 for a population from Kansas. An analysis of molecular variance of the hierarchically sampled populations found that the majority of the genetic variability (82.6%) occurred at the scale of the individual tree and only relatively small amounts among populations in trees from an orchard (5.0%) or within groups (i.e., orchard location populations) (12.5%). The results suggest little population differentiation in F. effusum in the southeastern United States, although φpt values of genetic distance for pairwise comparisons indicated some populations could be differentiated from others. There was evidence of linkage disequilibrium in certain populations, and the common occurrence of asexual reproduction in F. effusum could lead to measurable linkage disequilibrium under certain circumstances. However, the degree of genetic diversity and the scale over which diversity is distributed is evidence that F. effusum undergoes regular recombination despite no known sexual stage.
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Affiliation(s)
- C H Bock
- USDA-ARS-SEFTNRL, Byron, GA 31008, U.S.A
| | - B W Wood
- USDA-ARS-SEFTNRL, Byron, GA 31008, U.S.A
| | - K L Stevenson
- Department of Plant Pathology, Coastal Plain Experiment Station, The University of Georgia, Tifton, GA 31793, U.S.A
| | - R S Arias
- USDA-ARS-NPRL, Dawson, GA 39841, U.S.A
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Li L, Wang J, Zhang Z, Wang Y, Liu M, Jiang H, Chai R, Mao X, Qiu H, Liu F, Sun G. MoPex19, which is essential for maintenance of peroxisomal structure and woronin bodies, is required for metabolism and development in the rice blast fungus. PLoS One 2014; 9:e85252. [PMID: 24454828 PMCID: PMC3891873 DOI: 10.1371/journal.pone.0085252] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 11/24/2013] [Indexed: 11/19/2022] Open
Abstract
Peroxisomes are present ubiquitously and make important contributions to cellular metabolism in eukaryotes. They play crucial roles in pathogenicity of plant fungal pathogens. The peroxisomal matrix proteins and peroxisomal membrane proteins (PMPs) are synthesized in the cytosol and imported post-translationally. Although the peroxisomal import machineries are generally conserved, some species-specific features were found in different types of organisms. In phytopathogenic fungi, the pathways of the matrix proteins have been elucidated, while the import machinery of PMPs remains obscure. Here, we report that MoPEX19, an ortholog of ScPEX19, was required for PMPs import and peroxisomal maintenance, and played crucial roles in metabolism and pathogenicity of the rice blast fungus Magnaporthe oryzae. MoPEX19 was expressed in a low level and Mopex19p was distributed in the cytoplasm and newly formed peroxisomes. MoPEX19 deletion led to mislocalization of peroxisomal membrane proteins (PMPs), as well peroxisomal matrix proteins. Peroxisomal structures were totally absent in Δmopex19 mutants and woronin bodies also vanished. Δmopex19 exhibited metabolic deficiency typical in peroxisomal disorders and also abnormality in glyoxylate cycle which was undetected in the known mopex mutants. The Δmopex19 mutants performed multiple disorders in fungal development and pathogenicity-related morphogenesis, and lost completely the pathogenicity on its hosts. These data demonstrate that MoPEX19 plays crucial roles in maintenance of peroxisomal and peroxisome-derived structures and makes more contributions to fungal development and pathogenicity than the known MoPEX genes in the rice blast fungus.
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Affiliation(s)
- Ling Li
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Jiaoyu Wang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Zhen Zhang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Yanli Wang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Maoxin Liu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Hua Jiang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Rongyao Chai
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Xueqin Mao
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Haiping Qiu
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Fengquan Liu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
- * E-mail: (FL); (GS)
| | - Guochang Sun
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
- * E-mail: (FL); (GS)
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18
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PTS1 peroxisomal import pathway plays shared and distinct roles to PTS2 pathway in development and pathogenicity of Magnaporthe oryzae. PLoS One 2013; 8:e55554. [PMID: 23405169 PMCID: PMC3566003 DOI: 10.1371/journal.pone.0055554] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 12/27/2012] [Indexed: 12/03/2022] Open
Abstract
Peroxisomes participate in various important metabolisms and are required in pathogenicity of fungal plant pathogens. Peroxisomal matrix proteins are imported from cytoplasm into peroxisomes through peroxisomal targeting signal 1 (PTS1) or peroxisomal targeting signal 2 (PTS2) import pathway. PEX5 and PEX7 genes participate in the two pathways respectively. The involvement of PEX7 mediated PTS2 import pathway in fungal pathogenicity has been documented, while that of PTS1 remains unclear. Through null mutant analysis of MoPEX5, the PEX5 homolog in Magnaporthe oryzae, we report the crucial roles of PTS1 pathway in the development and host infection in the rice blast fungus, and compared with those of PTS2. We found that MoPEX5 disruption specifically blocked the PTS1 pathway. Δmopex5 was unable to use lipids as sole carbon source and lost pathogenicity completely. Similar as Δmopex7, Δmopex5 exhibited significant reduction in lipid utilization and mobilization, appressorial turgor genesis and H2O2 resistance. Additionally, Δmopex5 presented some distinct defects which were undetected in Δmopex7 in vegetative growth, conidial morphogenesis, appressorial morphogenesis and melanization. The results indicated that the PTS1 peroxisomal import pathway, in addition to PTS2, is required for fungal development and pathogenicity of the rice blast fungus, and also, as a main peroxisomal import pathway, played a more predominant role than PTS2.
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Nygren K, Strandberg R, Wallberg A, Nabholz B, Gustafsson T, García D, Cano J, Guarro J, Johannesson H. A comprehensive phylogeny of Neurospora reveals a link between reproductive mode and molecular evolution in fungi. Mol Phylogenet Evol 2011; 59:649-63. [DOI: 10.1016/j.ympev.2011.03.023] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 02/11/2011] [Accepted: 03/17/2011] [Indexed: 11/27/2022]
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20
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Ando S, Sato Y, Shigemori H, Shimizu T, Okada K, Yamane H, Jikumaru Y, Kamiya Y, Yamada K, Akimoto-Tomiyama C, Tanabe S, Nishizawa Y, Minami E. Identification and characterization of 2'-deoxyuridine from the supernatant of conidial suspensions of rice blast fungus as an infection-promoting factor in rice plants. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:519-532. [PMID: 21171893 DOI: 10.1094/mpmi-07-10-0172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We previously detected infection-promoting activity in the supernatant of the conidial suspension (SCS) of the rice blast fungus. In the present study, a molecule carrying the activity was purified and identified as 2'-deoxyuridine (dU). The infection-promoting activity of dU was strictly dependent on its chemical structure and displayed characteristics consistent with those of the SCS. Notably, the activity of dU was exclusively detected during interactions between rice and virulent isolates of the fungus, the number of susceptible lesions in leaf blades was increased by dU, and nonhost resistance in rice plants was not affected by treatment with dU. In addition, the expression of pathogensis-related genes, accumulation of H(2)O(2), and production of phytoalexins in rice in response to inoculation with virulent fungal isolates was not suppressed by dU. The infection-promoting activity of dU was not accompanied by elevated levels of endogenous abscissic acid, which is known to modify plant-pathogen interactions, and was not detected in interactions between oat plants and a virulent oat blast fungus isolate. Taken together, these results demonstrate that dU is a novel infection-promoting factor that acts specifically during compatible interactions between rice plants and rice blast fungus in a mode distinct from that of toxins and suppressors.
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Affiliation(s)
- Sugihiro Ando
- Division of Plant Sciences, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
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21
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Urban M, Motteram J, Jing HC, Powers S, Townsend J, Devonshire J, Pearman I, Kanyuka K, Franklin J, Hammond-Kosack K. Inactivation of plant infecting fungal and viral pathogens to achieve biological containment in drainage water using UV treatment. J Appl Microbiol 2011; 110:675-87. [DOI: 10.1111/j.1365-2672.2010.04917.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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22
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Douhan GW, de la Cerda KA, Huryn KL, Greer CA, Wong FP. Contrasting genetic structure between Magnaporthe grisea populations associated with the golf course turfgrasses Lolium perenne (perennial ryegrass) and Pennisetum clandestinum (kikuyugrass). PHYTOPATHOLOGY 2011; 101:85-91. [PMID: 21142782 DOI: 10.1094/phyto-08-10-0205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Gray leaf spot (GLS) disease of perennial ryegrass (Lolium perenne) and kikuyugrass (Pennisetum clandestinum) in golf courses in California was first noted in 2001 and 2003, respectively, and within 5 years had become well established. The causal agent of the disease is the fungus Magnaporthe grisea, which is known to consist primarily of clonal lineages that are highly host specific. Therefore, our objective was to investigate host specificity and population dynamics among isolates associated primarily from perennial ryegrass and kikuyugrass since the disease emerged at similar times in California. We also obtained isolates from additional hosts (tall fescue, St. Augustinegrass, weeping lovegrass, and rice) and from the eastern United States for comparative purposes. A total of 38 polymorphic amplified fragment length polymorphism makers were scored from 450 isolates which clustered by host with high bootstrap support (71 to 100%). Genetic structure between kikuyugrass and perennial ryegrass isolates differed significantly. Isolates from kikuyugrass were genotypically diverse (n = 34), possessed both mating types, and some tests for random mating could not be rejected, whereas isolates from perennial ryegrass were less genotypically diverse (n = 10) and only consisted of a single mating type. Low genotypic diversity was also found among the other host specific isolates which also only consisted of a single mating type. This is the first study to document evidence for the potential of sexual reproduction to occur in M. grisea isolates not associated with rice (Oryza sativa). Moreover, given the significant host specificity and contrasting genetic structures between turfgrass-associated isolates, the recent emergence of GLS on various grass hosts in California suggests that potential cultural practices or environmental changes have become conducive for the disease and that the primary inoculum may have already been present in the state, despite the fact that two genotypes associated with perennial ryegrass and St. Augustinegrass in California were the same as isolates collected from the eastern United States.
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Affiliation(s)
- Greg W Douhan
- Department of Plant Pathology and Microbiology, University of California, Riverside 92521, USA.
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Wang Y, Liu W, Hou Z, Wang C, Zhou X, Jonkers W, Ding S, Kistler HC, Xu JR. A novel transcriptional factor important for pathogenesis and ascosporogenesis in Fusarium graminearum. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:118-128. [PMID: 20795857 DOI: 10.1094/mpmi-06-10-0129] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Fusarium head blight or scab caused by Fusarium graminearum is an important disease of wheat and barley. The pathogen not only causes severe yield losses but also contaminates infested grains with mycotoxins. In a previous study, we identified several pathogenicity mutants by random insertional mutagenesis. One of these mutants was disrupted in the ZIF1 gene, which encodes a b-ZIP transcription factor unique to filamentous ascomycetes. The Δzif1 mutant generated by gene replacement was significantly reduced in deoxynivalenol (DON) production and virulence on flowering wheat heads. It was defective in spreading from inoculated florets to the rachis and other spikelets. Deletion of the ZIF1 ortholog MoZIF1 in the rice blast fungus also caused reductions in virulence and in invasive growth. In addition, the Δzif1 mutant is defective in sexual reproduction. Although it had normal male fertility, when selfed or mated as the female in outcrosess, the Δzif1 mutant produced small, pigmented perithecia that were sterile (lack of asci and ascospores), suggesting a female-specific role for ZIF1 during fertilization or ascus development. Similar female-specific defects in sexual reproduction were observed in the ΔMozif1 mutant. When mated as the female, the ΔMozif1 perithecia failed to develop long necks and asci or ascospores. The ZIF1 gene is well conserved in filamentous ascomycetes, particularly in the b-ZIP domain, which is essential for its function. Expression of ZIF1 in Magnaporthe oryzae complemented the defects of the ΔMozif1 mutant. These results indicate that this b-ZIP transcription factor is functionally conserved in these two fungal pathogens for plant infection and sexual reproduction.
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Affiliation(s)
- Yang Wang
- College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
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Hamer JE, Howard RJ, Chumley FG, Valent B. A mechanism for surface attachment in spores of a plant pathogenic fungus. Science 2010; 239:288-90. [PMID: 17769992 DOI: 10.1126/science.239.4837.288] [Citation(s) in RCA: 231] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Rice blast disease is caused by a fungus that attacks all above-ground parts of the rice plant. In a study of the means by which the fungus attaches to the hydrophobic rice leaf surface, it was found that spores(conidia) of the rice blast fungus Magnaporthe grisea have a mechanism for immediate and persistent attachment to various surfaces, including Teflon. This attachment occurs at the spore apex and is blocked by the addition of the lectin concanavalin A. Microscopy of hydrated conidia shows that a spore tip mucilage that binds concanavalin A is expelled specifically from the conidial apex before germ tube emergence. Ultrastructural analysis of dry conidia shows a large periplasmic deposit, presumably spore tip mucilage, at the apex. The results indicate a novel mechanism for the attachment of phytopathogenic fungal spores to a plant surface.
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Parsons KA, Chumley FG, Valent B. Genetic transformation of the fungal pathogen responsible for rice blast disease. Proc Natl Acad Sci U S A 2010; 84:4161-5. [PMID: 16593854 PMCID: PMC305044 DOI: 10.1073/pnas.84.12.4161] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The analysis of complex genetic determinants that control the ability of a fungus to colonize its host has been impaired by the lack of sophisticated genetic tools for characterizing important pathogens. We have developed a system for the genetic transformation of Magnaporthe grisea, the causal agent of rice blast disease, to overcome this limitation. A M. grisea arginine auxotroph was shown to contain a mutation (arg3-12) that abolishes ornithine carbamoyltransferase activity. M. grisea strains that contain arg3-12 were used as recipients in transformation experiments with plasmid pMA2, which carries the ArgB(+) gene from Aspergillus nidulans. Stable prototrophic transformants arose at a frequency of about 35 per microgram of plasmid DNA. Integration of single or multiple plasmid copies occurred at a single site in the genome of each transformant; rearrangements were often created during integration. When M. grisea genomic segments were incorporated into pMA2, the presence of any one of five different M. grisea segments did not greatly affect the efficiency of transformation. Integration via homologous recombination occurred when the donor plasmid was linearized by cleaving at a unique restriction site within the M. grisea segment.
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Affiliation(s)
- K A Parsons
- E. I. du Pont de Nemours & Company, Central Research and Development Department, Experimental Station, E402/2208, Wilmington, DE 19898
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Talbot NJ, Salch YP, Ma M, Hamer JE. Karyotypic Variation within Clonal Lineages of the Rice Blast Fungus, Magnaporthe grisea. Appl Environ Microbiol 2010; 59:585-93. [PMID: 16348876 PMCID: PMC202148 DOI: 10.1128/aem.59.2.585-593.1993] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have analyzed the karyotype of the rice blast fungus, Magnaporthe grisea, by using pulsed-filed gel electrophoresis. We tested whether the electrophoretic karyotype of an isolate was related to its pathotype, as determined by infection assays, or its genetic lineage, as determined by DNA fingerprinting. Highly reproducible electrophoretic karyotypes were obtained for a collection of U.S. and Chinese isolates representing a diverse collection of pathotypes and genetic lineages. Chromosomes ranged in size from 3 to 10 Mb. Although chromosome number was largely invariant, chromosome length polymorphisms were frequent. Minichromosomes were also found, although their presence was not ubiquitous. They ranged in number from 1 to 3 and in size from 470 kb to 2.2 Mb. Karyotypes were sufficiently variable as to obscure the obvious relatedness of isolates on the basis of pathogenicity assays or genetic lineage analysis by DNA fingerprinting. We documented that the electrophoretic karyotype of an isolate can change after prolonged serial transfer in culture and that this change did not alter the isolate's pathotype. The mechanisms bringing about karyotype variability involve deletions, translocations, and more complex rearrangements. We conclude that karyotypic variability in the rice blast fungus is a reflection of the lack of sexuality in wild populations which leads to the maintenance of neutral genomic rearrangements in clones of the fungus.
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Affiliation(s)
- N J Talbot
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907
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Betts MF, Tucker SL, Galadima N, Meng Y, Patel G, Li L, Donofrio N, Floyd A, Nolin S, Brown D, Mandel MA, Mitchell TK, Xu JR, Dean RA, Farman ML, Orbach MJ. Development of a high throughput transformation system for insertional mutagenesis in Magnaporthe oryzae. Fungal Genet Biol 2007; 44:1035-49. [PMID: 17600737 DOI: 10.1016/j.fgb.2007.05.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Revised: 05/01/2007] [Accepted: 05/10/2007] [Indexed: 11/24/2022]
Abstract
Towards the goal of disrupting all genes in the genome of Magnaporthe oryzae and identifying their function, a collection of >55,000 random insertion lines of M. oryzae strain 70-15 were generated. All strains were screened to identify genes involved in growth rate, conidiation, pigmentation, auxotrophy, and pathogenicity. Here, we provide a description of the high throughput transformation and analysis pipeline used to create our library. Transformed lines were generated either by CaCl(2)/PEG treatment of protoplasts with DNA or by Agrobacterium tumefaciens-mediated transformation (ATMT). We describe the optimization of both approaches and compare their efficiency. ATMT was found to be a more reproducible method, resulting in predominantly single copy insertions, and its efficiency was high with up to 0.3% of conidia being transformed. The phenotypic data is accessible via a public database called MGOS and all strains are publicly available. This represents the most comprehensive insertional mutagenesis analysis of a fungal pathogen.
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Affiliation(s)
- Melania F Betts
- Department of Plant Sciences, Division of Plant Pathology and Microbiology, University of Arizona, Tucson, AZ 85721-0036, USA
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Wilson RA, Jenkinson JM, Gibson RP, Littlechild JA, Wang ZY, Talbot NJ. Tps1 regulates the pentose phosphate pathway, nitrogen metabolism and fungal virulence. EMBO J 2007; 26:3673-85. [PMID: 17641690 PMCID: PMC1949003 DOI: 10.1038/sj.emboj.7601795] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Accepted: 06/18/2007] [Indexed: 11/08/2022] Open
Abstract
Trehalose fulfils a wide variety of functions in cells, acting as a stress protectant, storage carbohydrate and compatible solute. Recent evidence, however, indicates that trehalose metabolism may exert important regulatory roles in the development of multicellular eukaryotes. Here, we show that in the plant pathogenic fungus Magnaporthe grisea trehalose-6-phosphate (T6P) synthase (Tps1) is responsible for regulating the pentose phosphate pathway, intracellular levels of NADPH and fungal virulence. Tps1 integrates glucose-6-phosphate (G6P) metabolism with nitrogen source utilisation, and thereby regulates the activity of nitrate reductase. Activity of Tps1 requires an associated regulator protein Tps3, which is also necessary for pathogenicity. Tps1 controls expression of the nitrogen metabolite repressor gene, NMR1, and is required for expression of virulence-associated genes. Functional analysis of Tps1 indicates that its regulatory functions are associated with binding of G6P, but independent of Tps1 catalytic activity. Taken together, these results demonstrate that Tps1 is a central regulator for integration of carbon and nitrogen metabolism, and plays a pivotal role in the establishment of plant disease.
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Affiliation(s)
| | | | | | | | - Zheng-Yi Wang
- School of Biosciences, University of Exeter, Exeter, UK
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Busso C, Nobuyoshi Kaneshima E, Franco FDA, de Castro-Prado MAA. Caracterización molecular y genética de aislamientos patógenos de Pyricularia grisea del trigo (Triticum aestivum Lam.) y triticale (x Triticosecale Wittmack) en la Provincia de Paraná, Brasil. Rev Iberoam Micol 2007; 24:167-70. [PMID: 17604441 DOI: 10.1016/s1130-1406(07)70037-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Isolates of Pyricularia grisea from wheat (Triticum aestivum Lam.) and triticale (x Triticosecale Wittmack) spikes with blast symptoms were analyzed by classical (VCG) and molecular (RAPD) techniques. P. grisea mutants, unable to use sodium nitrate (nit) as nitrogen source, were obtained with potassium chlorate. For vegetative compatibility (VCG) tests, genetically complementary nit mutant pairs were inoculated in a medium with sodium nitrate as a single nitrogen source. P. grisea isolates were divided into two vegetative compatibility groups and two RAPD groups. Since vegetative compatible strains may mutually exchange genetic and cytoplasmatic material, the contribution of the parasexual cycle in the genetic variability of Brazilian P. grisea isolates is discussed.
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Affiliation(s)
- Cleverson Busso
- Department of Cell Biology and Genetics, State University of Maringá, Avenida Colombo 5790, Maringá, PR Brazil 87020-900
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Xiong R, Liu J, Zhou Y, Fan Y, Zheng X. Screening and identification of mutants of Magnaporthe grisea by REMI. ACTA ACUST UNITED AC 2007. [DOI: 10.1007/s11703-007-0030-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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31
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Ebbole DJ. Magnaporthe as a model for understanding host-pathogen interactions. ANNUAL REVIEW OF PHYTOPATHOLOGY 2007; 45:437-56. [PMID: 17489691 DOI: 10.1146/annurev.phyto.45.062806.094346] [Citation(s) in RCA: 270] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The rice blast pathosystem has been the subject of intense interest in part because of the importance of the disease to world agriculture, but also because both Magnaporthe oryzae and its host are amenable to advanced experimental approaches. The goal of this review is to provide an overview of the system and to point out recent significant studies that update our understanding of the biology of M. oryzae. The genome sequence of M. oryzae has provided insight into how genome structure and pathogen population genetic variability has been shaped by transposable elements. The sequence allows systematic approaches to long-standing areas of investigation, including pathogen development and the molecular basis of compatible and incompatible interactions with its host. Rice blast provides an integrated system to illustrate most of the important concepts governing fungal/plant interactions and serves as an excellent starting point for gaining a broad perspective of issues in plant pathology.
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Affiliation(s)
- Daniel J Ebbole
- Program for the Biology of Filamentous Fungi, Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas 77843-2132, USA.
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Noguchi MT, Yasuda N, Fujita Y. Evidence of Genetic Exchange by Parasexual Recombination and Genetic Analysis of Pathogenicity and Mating Type of Parasexual Recombinants in Rice Blast Fungus, Magnaporthe oryzae. PHYTOPATHOLOGY 2006; 96:746-750. [PMID: 18943148 DOI: 10.1094/phyto-96-0746] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
ABSTRACT A selectable marker gene conferring resistance to bialaphos (BI) was introduced into rice blast isolate Y90-71BI and another conferring resistance to blasticidin S (BS) into isolate 3514-R-2BS of Magnaporthe oryzae to demonstrate exchange of DNA. Colonies obtained from co-cultures of these two isolates were resistant to both BI and BS and had both resistance genes as shown by Southern blot analysis of their genomic DNA. Conidia from these BI-BS-resistant isolates had only one nucleus per cell after staining with 4',6-diamidino-2-phenylindole (DAPI). Using flow cytometry, however, these BI-BS-resistant isolates were found to be haploid. Segregation of BI-BS-resistant isolates for pathogenicity (avirulence to virulence) on rice line K59-1 was consistent with a 1:1 ratio, as was segregation for mating type. These BI-BS-resistant isolates were thus apparently derived from parasexual exchange of DNA and the segregation of pathogenicity and of mating type of the parasexual recombinants might correspond to that of the progeny of the offspring of the sexual cross.
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Fry FH, Okarter N, Baynton-Smith C, Kershaw MJ, Talbot NJ, Jacob C. Use of a substrate/alliinase combination to generate antifungal activity in situ. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2005; 53:574-580. [PMID: 15686404 DOI: 10.1021/jf048481j] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Allicin, an active ingredient of garlic, possesses a range of antimicrobial properties. Unfortunately, certain properties of the compound, such as chemical instability and low miscibility with water, have hampered its practical use in the past. Here, we show that it is possible to use a binary system consisting of the plant enzyme alliinase and its substrate alliin to generate allicin, and hence antifungal activity, in situ. During application, the two inactive components generate compounds that inhibit growth and infection-related development of the rice blast fungus Magnaporthe grisea. It is therefore possible to "trigger" biological activity in a controlled, yet effective manner. Apart from circumventing many of the drawbacks of allicin, this binary system has additional important advantages, such as low toxicity of its individual components and selective activation. Importantly, alliinase is also able to use different substrates, therefore paving the way to a range of novel, binary antimicrobial systems with custom-made chemical and biochemical properties.
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Affiliation(s)
- Fiona H Fry
- School of Biological and Chemical Sciences, University of Exeter, Stocker Road, Exeter, Devon EX4 4QD, United Kingdom
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Viji G, Uddin W, O'Neill NR, Mischke S, Saunders JA. Genetic Diversity of Sclerotinia homoeocarpa Isolates from Turfgrasses from Various Regions in North America. PLANT DISEASE 2004; 88:1269-1276. [PMID: 30795324 DOI: 10.1094/pdis.2004.88.11.1269] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Sixty-seven isolates of Sclerotinia homoeocarpa, causing dollar spot disease in creeping bentgrass, annual bluegrass, Bermudagrass, and perennial ryegrass turf, collected from 23 golf courses in various geographical regions of the United States and Canada between 1972 and 2001, were characterized by vegetative compatibility, genetic diversity, and pathogenicity. Eleven vegetative compatibility groups (VCGs A to K) were identified among the isolates tested in this study, and five of them (VCGs G to K) were new. VCG B was the most predominant group, typifying 33 isolates (51%) tested. S. homoeocarpa isolates collected from golf courses in Pennsylvania belonged to seven VCGs (A, B, E, F, G, I, and K), whereas three groups were observed in those collected from New York (B, E, and G) and New Jersey (E, H, and I). Two isolates, one each from Pennsylvania and Canada, were incompatible when paired with the tester isolates in all possible combinations, and did not fall into any known VCG. An isolate collected from Canada was compatible with tester isolates from two VCGs (C and D). Genetic analyses using amplified fragment length polymorphism (AFLP) showed the presence of two genetically distinct groups, designated as major group and the minor group. The major group included 36 isolates collected from various golf courses in the United States and Canada. Two isolates collected from bermudagrass in Florida formed a separate cluster, the minor group. Isolates that belonged to the major group were further divided into two subgroups (1 and 2). Subgroup 1 consisted of all the isolates that belonged to VCGs A, E, G, H, and I. Three of the four isolates that belonged to VCG K also were clustered with isolates of subgroup 1. Subgroup 2 consisted of all the isolates from VCG B, and one each from VCGs F and K. Pathogenicity assays on Penncross creeping bentgrass showed significant differences (P = 0.05) in virulence among the isolates. Overall, a relationship between virulence and VCGs was observed, in which certain virulence groups corresponded to specific VCGs; however, such a relationship was not observed between virulence and AFLPs. Close similarity among isolates of S. homoeocarpa collected from different locations in the United States and Canada suggests that isolates of the same genotype could be involved in outbreaks of dollar spot epidemics at multiple locations.
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Affiliation(s)
- G Viji
- Department of Plant Pathology, The Pennsylvania State University, University Park 16802
| | - W Uddin
- Department of Plant Pathology, The Pennsylvania State University, University Park 16802
| | - N R O'Neill
- United States Department of Agriculture-Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, MD 20705
| | - S Mischke
- United States Department of Agriculture-Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, MD 20705
| | - J A Saunders
- United States Department of Agriculture-Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, MD 20705
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Abstract
We identified a polyketide synthase (PKS) gene, pksN, from a strain of Nectria haematococca by complementing a mutant unable to synthesize a red perithecial pigment. pksN encodes a 2,106-amino-acid polypeptide with conserved motifs characteristic of type I PKS enzymatic domains: beta-ketoacyl synthase, acyltransferase, duplicated acyl carrier proteins, and thioesterase. The pksN product groups with the Aspergillus nidulans WA-type PKSs involved in conidial pigmentation and melanin, bikaverin, and aflatoxin biosynthetic pathways. Inactivation of pksN did not cause any visible change in fungal growth, asexual sporulation, or ascospore formation, suggesting that it is involved in a specific developmental function. We propose that pksN encodes a novel PKS required for the perithecial red pigment biosynthesis.
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Affiliation(s)
- Stephane Graziani
- Institut de Génétique et Microbiologie, Université Paris-Sud, 91405 Orsay Cedex, France
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Li L, Xue C, Bruno K, Nishimura M, Xu JR. Two PAK kinase genes, CHM1 and MST20, have distinct functions in Magnaporthe grisea. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2004; 17:547-556. [PMID: 15141959 DOI: 10.1094/mpmi.2004.17.5.547] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In the rice blast fungus Magnaporthe grisea, the Pmk1 mitogen-activated protein (MAP) kinase is essential for appressorium formation and infectious growth. PMK1 is homologous to yeast Fus3 and Kss1 MAP kinases that are known to be regulated by the Ste20 PAK kinase for activating the pheromone response and filamentation pathways. In this study, we isolated and characterized two PAK genes, CHM1 and MST20, in M. grisea. Mutants disrupted in MST20 were reduced in aerial hyphae growth and conidiation, but normal in growth rate, appressorium formation, penetration, and plant infection. In chm1 deletion mutants, growth, conidiation, and appressorium formation were reduced significantly. Even though appressoria formed by chm1 mutants were defective in penetration, chm1 mutants were able to grow invasively on rice leaves and colonize through wounds. The chm1 mutants were altered in conidiogenesis and produced conidia with abnormal morphology. Hyphae of chm1 mutants had normal septation, but the length of hyphal compartments was reduced. On nutritionally poor oatmeal agar, chm1 mutants were unstable and produced sectors that differed from original chm1 mutants in growth rate, conidiation, or colony morphology. However, none of the monoconidial cultures derived from these spontaneous sectors were normal in appressorial penetration and fungal pathogenesis. These data suggest that MST20 is dispensable for plant infection in M. grisea, but CHM1 plays a critical role in appressorium formation and penetration. Both mst20 and chm1 deletion mutants were phenotypically different from the pmk1 mutant that is defective in appressorium formation and infectious hyphae growth. It is likely that MST20 and CHM1 individually play no critical role in activating the PMK1 MAP kinase pathway during appressorium formation and infectious hyphae growth. However, CHM1 appears to be essential for appressorial penetration and CHM1 and MST20 may have redundant functions in M. grisea.
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Affiliation(s)
- Lei Li
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
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Tanzer MM, Arst HN, Skalchunes AR, Coffin M, Darveaux BA, Heiniger RW, Shuster JR. Global nutritional profiling for mutant and chemical mode-of-action analysis in filamentous fungi. Funct Integr Genomics 2003; 3:160-70. [PMID: 12898394 DOI: 10.1007/s10142-003-0089-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2003] [Revised: 06/06/2003] [Accepted: 06/11/2003] [Indexed: 11/24/2022]
Abstract
We describe a method for gene function discovery and chemical mode-of-action analysis via nutrient utilization using a high throughput Nutritional Profiling platform suitable for filamentous microorganisms. We have optimized the growth conditions for each fungal species to produce reproducible optical density growth measurements in microtiter plates. We validated the Nutritional Profiling platform using a nitrogen source utilization assay to analyze 21 Aspergillus nidulans strains with mutations in the master nitrogen regulatory gene, areA. Analysis of these data accurately reproduced expected results and provided new data to demonstrate that this platform is suitable for fine level phenotyping of filamentous fungi. Next, we analyzed the differential responses of two fungal species to a glutamine synthetase inhibitor, illustrating chemical mode-of-action analysis. Finally, a comparative phenotypic study was performed to characterize carbon catabolite repression in four fungal species using a carbon source utilization assay. The results demonstrate differentiation between two Aspergillus species and two diverse plant pathogens and provide a wealth of new data on fungal nutrient utilization. Thus, these assays can be used for gene function and chemical mode-of-action analysis at the whole organism level as well as interspecies comparisons in a variety of filamentous fungi. Additionally, because uniform distribution of growth within wells is maintained, comparisons between yeast and filamentous forms of a single organism can be performed.
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Affiliation(s)
- Matthew M Tanzer
- Paradigm Genetics, Building 1A, 108 TW Alexander Drive, NC 27709, Research Triangle Park, USA,
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Iyer G, Chattoo BB. Purification and characterization of laccase from the rice blast fungus,Magnaporthe grisea. FEMS Microbiol Lett 2003; 227:121-6. [PMID: 14568157 DOI: 10.1016/s0378-1097(03)00658-x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A 70-kDa extracellular laccase was purified from the rice blast fungus Magnaporthe grisea using gel filtration and ion exchange chromatography The procedure provided 282-fold purification with a specific enzyme activity of 225.91 U mg(-1) and a yield of 11.92%. The enzyme oxidized a wide range of substrates. The highest level of oxidation was detected with syringaldazine as the substrate. Using syringaldazine as the substrate, the enzyme exhibited a pH optimum of 6 and temperature optimum of 30 degrees C, and its K(m) was 0.118 mM. The enzyme was strongly inhibited by Cu-chelating agents.
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Affiliation(s)
- Gopal Iyer
- Plant and Microbial Biology Department, 111 Koshland Hall, University of California, Berkeley, CA 94720, USA.
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Abstract
Fungi (kingdom Mycota) and oomycetes (kingdom Stramenopila, phylum Oomycota) are crucially important in the nutrient cycles of the world. Their interactions with plants sometimes benefit and sometimes act to the detriment of humans. Many fungi establish ecologically vital mutualisms, such as in mycorrhizal fungi that enhance nutrient acquisition, and endophytes that combat insects and other herbivores. Other fungi and many oomycetes are plant pathogens that devastate natural and agricultural populations of plant species. Studies of fungal and oomycete evolution were extraordinarily difficult until the advent of molecular phylogenetics. Over the past decade, researchers applying these new tools to fungi and oomycetes have made astounding new discoveries, among which is the potential for interspecific hybridization. Consequences of hybridization among pathogens include adaptation to new niches such as new host species, and increased or decreased virulence. Hybrid mutualists may also be better adapted to new hosts and can provide greater or more diverse benefits to host plants.
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Affiliation(s)
- C L Schardl
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky 40546-0091, USA.
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Urban M, Mott E, Farley T, Hammond-Kosack K. The Fusarium graminearum MAP1 gene is essential for pathogenicity and development of perithecia. MOLECULAR PLANT PATHOLOGY 2003; 4:347-59. [PMID: 20569395 DOI: 10.1046/j.1364-3703.2003.00183.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
SUMMARY Fusarium graminearum is the causal agent of ear blight disease of cereals. Infection occurs at anthesis when ascospores and/or conidia directly penetrate exposed anther and ovary tissue. The hemibiotrophic hyphae colonize floral tissues and developing grains to cause premature ear senescence. During infection, Fusarium hyphae can also produce hazardous trichothecene mycotoxins, thereby posing a threat to human and animal health and safety. The Fusarium MAP1 gene was identified using a PCR approach by its homology to a known pathogenicity gene of Magnaporthe grisea, the mitogen-activated protein kinase gene PMK1. Gene replacement F. graminearum map1 mutants were non-pathogenic on wheat flowers and roots, and also could not infect wounded wheat floral tissue or tomato fruits. Unlike the wild-type strain, map1 mutant inoculations did not compromise grain yield. Map1 mutants lost their ability to form perithecia in vitro, but their rate of asexual conidiation was unaffected. DON mycotoxin production in planta was still detected. Collectively, the observed phenotypes suggest that the Map1 signalling protein controls multiple events in disease establishment and propagation. Novel approaches to control Fusarium ear blight disease by blocking perithecial development are discussed.
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Affiliation(s)
- Martin Urban
- Plant-Pathogen Interactions Division, Rothamsted Research, Harpenden, Herts, AL5 2JQ, UK
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42
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Avila-Adame C, Köller W. Impact of alternative respiration and target-site mutations on responses of germinating conidia of Magnaporthe grisea to Qo-inhibiting fungicides. PEST MANAGEMENT SCIENCE 2003; 59:303-309. [PMID: 12639047 DOI: 10.1002/ps.638] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Qo-inhibiting fungicides act as respiration inhibitors by binding to the Qo center of cytochrome b. Sensitivities of fungi to Qo inhibitors can be influenced by the induction of alternative respiration or by mutational changes of the cytochrome b target site. Previous studies on both mechanisms in Magnaporthe grisea (Hebert) Barr were focused on the mycelial stage of the pathogen. The present study describes the expression and impact of both resistance mechanisms during the stage of conidia germination. In the absence of a host, alternative respiration provided a >500-fold rescue from azoxystrobin during the germination of conidia derived from four wild-type isolates of M. grisea. This rescue potential during conidia gemination was substantially more pronounced than for mycelial growth. However, the pronounced effectiveness of alternative respiration during conidia germination was not apparent when barley leaves were protected with azoxystrobin prior to inoculation with conidia. In a comparison of a wild-type strain and an alternative respiration-deficient mutant, azoxystrobin efficacies in suppressing symptom development differed by a factor of two, with full disease control achieved for both genotypes at 1 microg ml(-1) azoxystrobin. In contrast, conidia derived from two QoI-resistant target site mutants were highly resistant to azoxystrobin and trifloxystrobin and fully capable of infecting leaf surfaces protected with 10 microg ml(-1) of azoxystrobin. Both target-site mutants had emerged spontaneously in the presence of high azoxystrobin doses when residual mycelial growth was supported by alternative respiration. The effective silencing of alternative respiration in protective applications of Qo-inhibiting fungicides might constitute a strategy of slowing the emergence of highly resistant target site mutants.
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Affiliation(s)
- Cruz Avila-Adame
- Department of Plant Pathology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456, USA
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43
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Avila-Adame C, Köller W. Characterization of spontaneous mutants of Magnaporthe grisea expressing stable resistance to the Qo-inhibiting fungicide azoxystrobin. Curr Genet 2003; 42:332-8. [PMID: 12612806 DOI: 10.1007/s00294-002-0356-1] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2002] [Revised: 07/13/2002] [Accepted: 10/11/2002] [Indexed: 11/26/2022]
Abstract
The class of Qo-inhibiting fungicides (QoIs) act as respiration inhibitors by binding to the Qo center of cytochrome b. The longevity of these fungicides has been challenged by the selection of fungal sub-populations resisting high doses of QoI fungicides, with a G143A amino acid exchange in the cytochrome b target site identified as the most common cause of resistance. In contrast, the mechanism of alternative respiration, as another mechanism of fungal QoI resistance, has thus far not been affiliated with practical resistance. In the present study, azoxystrobin-resistant mutants of Magnaporthe grisea were generated and characterized. Emergence of these spontaneous mutants was facilitated when resting melanized mycelia were allowed to escape full inhibition by azoxystrobin. This escape was related to the intactness of alternative respiration, indicating that residual expression of this rescue mechanism was involved in the spontaneous emergence of target-site mutants. The two mutants characterized resisted high doses of the QoI, azoxystrobin, with resistance factors exceeding 1,000. Two different mutations of the cytochrome b gene were identified as exchanges of guanine, leading to a G143A or a G143S amino acid exchange. Resistance of both target-site mutants remained stable during four consecutive disease cycles in the absence of azoxystrobin. Several parameters tested to measure fitness penalties inherent to the mutational changes revealed that the G143A mutant was not compromised. In contrast, the conidia production of the G143S mutant was significantly lower under both saprophytic and pathogenic conditions of reproduction.
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Affiliation(s)
- Cruz Avila-Adame
- Department of Plant Pathology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456, USA
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44
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Bourett TM, Sweigard JA, Czymmek KJ, Carroll A, Howard RJ. Reef coral fluorescent proteins for visualizing fungal pathogens. Fungal Genet Biol 2002; 37:211-20. [PMID: 12431456 DOI: 10.1016/s1087-1845(02)00524-8] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The fluorescent proteins AmCyan, ZsGreen, ZsYellow, and AsRed, modified versions of proteins identified recently from several Anthozoa species of reef corals, were expressed for the first time in a heterologous system and used for imaging two different fungal plant pathogens. When driven by strong constitutive fungal promotors, expression of these reef coral fluorescent proteins yielded bright cytoplasmic fluorescence in Fusarium verticillioides and Magnaporthe grisea, and had no detectable effect on either growth rate or the ability to cause disease. Differential intracellular localization of the fluorescent proteins resulted in the discrimination of many subcellular organelles by confocal and multi-photon microscopy, and facilitated monitoring of such details as organelle dynamics and changes in the permeability of the nuclear envelope. AmCyan and ZsGreen were sufficiently excited at 855 and 880 nm, respectively, to allow for time-resolved in planta imaging by two-photon microscopy.
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Affiliation(s)
- Timothy M Bourett
- DuPont Crop Genetics, Experimental Station E402/2233, Powder Mill Road, Wilmington, DE 19880-0402, USA
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45
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Soanes DM, Kershaw MJ, Cooley RN, Talbot NJ. Regulation of the MPG1 hydrophobin gene in the rice blast fungus Magnaporthe grisea. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2002; 15:1253-1267. [PMID: 12481998 DOI: 10.1094/mpmi.2002.15.12.1253] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The hydrophobin-encoding gene MPG1 of the rice blast fungus Magnaporthe grisea is highly expressed during the initial stages of host plant infection and targeted deletion of the gene results in a mutant strain that is reduced in virulence, conidiation, and appressorium formation. The green fluorescent protein-encoding allele sGFP was used as a reporter to investigate regulatory genes that control MPG1 expression. The MAP kinase-encoding gene PMK1 and the wide domain regulators of nitrogen source utilization, NPR1 and NUT1, were required for full expression of MPG1 in response to starvation stress. The CPKA gene, encoding the catalytic subunit of protein kinase A, was required for repression of MPG1 during growth in rich nutrient conditions. During appressorium morphogenesis, high-level MPG1 expression was found to require the CPKA and NPR1 genes. Expression of a destabilized GFP allele indicated that de novo MPG1 expression occurs during appressorium formation. Three regions of the MPG1 promoter were identified which are required for high-level expression of MPG1 during appressorium formation and are necessary for the biological activity of the MPG1 hydrophobin during spore formation and plant infection.
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Affiliation(s)
- Darren M Soanes
- School of Biological Sciences, University of Exeter, Washington Singer Laboratories, Perry Road, Exeter, EX4 4QG, UK
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46
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Clay K, Schardl C. Evolutionary Origins and Ecological Consequences of Endophyte Symbiosis with Grasses. Am Nat 2002; 160 Suppl 4:S99-S127. [DOI: 10.1086/342161] [Citation(s) in RCA: 705] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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47
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Avila-Adame C, Köller W. Disruption of the alternative oxidase gene in Magnaporthe grisea and its impact on host infection. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2002; 15:493-500. [PMID: 12036280 DOI: 10.1094/mpmi.2002.15.5.493] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Plants and numerous fungi including Magnaporthe grisea protect mitochondria from interference by respiration inhibitors by expressing alternative oxidase, the enzymatic core of alternative respiration. The alternative oxidase gene AOXMg of M. grisea was disrupted. Several lines of evidence suggested that the disruption of AOXMg was sufficient to completely curb the expression of alternative respiration. In the infection of barley leaves, several AOXMg-minus and, thus, alternative respiration-deficient mutants of M. grisea retained their pathogenicity without significant impairment of virulence. However, differences between the wild-type strain and an AOXMg-minus mutant were apparent under oxidative stress conditions generated by the treatment of infected barley leaves with the commercial respiration inhibitor azoxystrobin. Symptom development was effectively suppressed on leaves infected with the alternative respiration-deficient mutant, while lesions on leaves infected with the wild-type strain continued to develop at much higher inhibitor doses. However, respective lesions rarely developed to the stage of full maturity. The results did not conform to a previous model implying that expression of alternative respiration is silenced during pathogenesis by the presence of constitutive plant antioxidants. Rather, alternative respiration provided protection from azoxystrobin during both saprophytic and infectious stages of the pathogen. The nature of similar oxidative stress conditions in the ecology of M. grisea remains an open question.
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Affiliation(s)
- Cruz Avila-Adame
- Department of Plant Pathology, Cornell University, New York State Agricultural Experiment Station, Geneva 14456, USA
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48
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Park G, Xue C, Zheng L, Lam S, Xu JR. MST12 regulates infectious growth but not appressorium formation in the rice blast fungus Magnaporthe grisea. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2002; 15:183-92. [PMID: 11952120 DOI: 10.1094/mpmi.2002.15.3.183] [Citation(s) in RCA: 158] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In the rice blast fungus Magnaporthe grisea, a mitogen-activated protein kinase gene, PMK1, is known to regulate appressorium formation and infectious hyphae growth. Since PMK1 is homologous to the FUS3 and KSS1 genes that regulate the transcription factor STE12 in yeast, we functionally characterized the STE12 homologue in M. grisea (MST12). A polymerase chain reaction-based approach was used to isolate the MST12 gene that is homologous to yeast STE12. Four mst12 deletion mutants were isolated by gene replacement. No obvious defect in vegetative growth, conidiation, or conidia germination was observed in mst12 mutants. However, mst12 mutants were nonpathogenic on rice and barley leaves. In contrast to pmk1 mutants that did not form appressoria, mst12 mutants produced typical dome-shaped and melanized appressoria. However, the appressoria formed by mst12 mutants failed to penetrate onion epidermal cells. When inoculated through wound sites, mst12 mutants failed to cause spreading lesions and appeared to be defective in infectious growth. These data indicate that MST12 may function downstream of PMK1 to regulate genes involved in infectious hyphae growth. A transcription factor or factors other than MST12 must exist in M. grisea and function downstream from PMK1 for appressorium formation.
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Affiliation(s)
- Gyungsoon Park
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907 USA
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49
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Balhadère PV, Talbot NJ. PDE1 encodes a P-type ATPase involved in appressorium-mediated plant infection by the rice blast fungus Magnaporthe grisea. THE PLANT CELL 2001; 13:1987-2004. [PMID: 11549759 PMCID: PMC139447 DOI: 10.1105/tpc.010056] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/12/2001] [Accepted: 06/13/2001] [Indexed: 05/20/2023]
Abstract
Plant infection by the rice blast fungus Magnaporthe grisea is brought about by the action of specialized infection cells called appressoria. These infection cells generate enormous turgor pressure, which is translated into an invasive force that allows a narrow penetration hypha to breach the plant cuticle. The Magnaporthe pde1 mutant was identified previously by restriction enzyme-mediated DNA integration mutagenesis and is impaired in its ability to elaborate penetration hyphae. Here we report that the pde1 mutation is the result of an insertion into the promoter of a P-type ATPase-encoding gene. Targeted gene disruption confirmed the role of PDE1 in penetration hypha development and pathogenicity but highlighted potential differences in PDE1 regulation in different Magnaporthe strains. The predicted PDE1 gene product was most similar to members of the aminophospholipid translocase group of P-type ATPases and was shown to be a functional homolog of the yeast ATPase gene ATC8. Spatial expression studies showed that PDE1 is expressed in germinating conidia and developing appressoria. These findings implicate the action of aminophospholipid translocases in the development of penetration hyphae and the proliferation of the fungus beyond colonization of the first epidermal cell.
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Affiliation(s)
- P V Balhadère
- School of Biological Sciences, University of Exeter, Washington Singer Laboratories, Perry Road, Exeter EX4 4QG, United Kingdom
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50
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Balhadère PV, Talbot NJ. PDE1 encodes a P-type ATPase involved in appressorium-mediated plant infection by the rice blast fungus Magnaporthe grisea. THE PLANT CELL 2001; 13:1987-2004. [PMID: 11549759 DOI: 10.1105/tpc.13.9.1987] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Plant infection by the rice blast fungus Magnaporthe grisea is brought about by the action of specialized infection cells called appressoria. These infection cells generate enormous turgor pressure, which is translated into an invasive force that allows a narrow penetration hypha to breach the plant cuticle. The Magnaporthe pde1 mutant was identified previously by restriction enzyme-mediated DNA integration mutagenesis and is impaired in its ability to elaborate penetration hyphae. Here we report that the pde1 mutation is the result of an insertion into the promoter of a P-type ATPase-encoding gene. Targeted gene disruption confirmed the role of PDE1 in penetration hypha development and pathogenicity but highlighted potential differences in PDE1 regulation in different Magnaporthe strains. The predicted PDE1 gene product was most similar to members of the aminophospholipid translocase group of P-type ATPases and was shown to be a functional homolog of the yeast ATPase gene ATC8. Spatial expression studies showed that PDE1 is expressed in germinating conidia and developing appressoria. These findings implicate the action of aminophospholipid translocases in the development of penetration hyphae and the proliferation of the fungus beyond colonization of the first epidermal cell.
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Affiliation(s)
- P V Balhadère
- School of Biological Sciences, University of Exeter, Washington Singer Laboratories, Perry Road, Exeter EX4 4QG, United Kingdom
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