<i>Magnaporthe grisea</i> Pathogenicity Genes Obtained Through Insertional Mutagenesis

Sweigard, James A.; Carroll, Anne; Farrall, Leonard; Chumley, Forrest G.; Valent, Barbara

doi:10.1094/mpmi.1998.11.5.404

Cited by 243 publications

(189 citation statements)

References 35 publications

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“…To identify novel pathogenicity mutants of the rice blast fungus, an insertional library of M. oryzae P131 was generated by restriction enzyme-mediated integration (REMI), as described previously (Sweigard et al, 1998). After screening a library of 13,500 hygromycin-resistant transformants, a mutant, MO2393, was found that was significantly reduced in virulence.…”

Section: Isolation and Characterization Of Alg3 Mutantsmentioning

confidence: 99%

“…To identify the gene disrupted in MO2393, genomic regions flanking the insertion site were isolated by plasmid rescue (Sweigard et al, 1998). Sequence analysis revealed that the transforming vector pV4 was inserted in the coding region of a gene, MGG_08010.6, at a position 688 bp downstream of the start codon ( Figure 1C).…”

Section: Isolation and Characterization Of Alg3 Mutantsmentioning

confidence: 99%

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N-Glycosylation of Effector Proteins by an α-1,3-Mannosyltransferase Is Required for the Rice Blast Fungus to Evade Host Innate Immunity

et al. 2014

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Plant pathogenic fungi deploy secreted effectors to suppress plant immunity responses. These effectors operate either in the apoplast or within host cells, so they are putatively glycosylated, but the posttranslational regulation of their activities has not been explored. In this study, the ASPARAGINE-LINKED GLYCOSYLATION3 (ALG3)-mediated N-glycosylation of the effector, Secreted LysM Protein1 (Slp1), was found to be essential for its activity in the rice blast fungus Magnaporthe oryzae. ALG3 encodes an a-1,3-mannosyltransferase for protein N-glycosylation. Deletion of ALG3 resulted in the arrest of secondary infection hyphae and a significant reduction in virulence. We observed that Dalg3 mutants induced massive production of reactive oxygen species in host cells, in a similar manner to Dslp1 mutants, which is a key factor responsible for arresting infection hyphae of the mutants. Slp1 sequesters chitin oligosaccharides to avoid their recognition by the rice (Oryza sativa) chitin elicitor binding protein CEBiP and the induction of innate immune responses, including reactive oxygen species production. We demonstrate that Slp1 has three N-glycosylation sites and that simultaneous Alg3-mediated N-glycosylation of each site is required to maintain protein stability and the chitin binding activity of Slp1, which are essential for its effector function. These results indicate that Alg3-mediated N-glycosylation of Slp1 is required to evade host innate immunity.

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Section: Isolation and Characterization Of Alg3 Mutantsmentioning

confidence: 99%

Section: Isolation and Characterization Of Alg3 Mutantsmentioning

confidence: 99%

N-Glycosylation of Effector Proteins by an α-1,3-Mannosyltransferase Is Required for the Rice Blast Fungus to Evade Host Innate Immunity

et al. 2014

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“…Mycelia harvested from 2-d-old 53YEG (0.5% yeast extract and 1% glucose) cultures shaken at 150 rpm were used for isolation of genomic DNA and protoplasts (Sweigard et al, 1998;Zhao et al, 2005). Hygromycin-or zeocin-resistant transformants were selected on media supplemented with 250 mg/mL hygromycin B or 150 mg/mL zeocin (Invitrogen).…”

Section: Culture Conditions and Genetic Manipulationsmentioning

confidence: 99%

The Tig1 Histone Deacetylase Complex Regulates Infectious Growth in the Rice Blast Fungus Magnaporthe oryzae

et al. 2010

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Magnaporthe oryzae is the most damaging fungal pathogen of rice (Oryza sativa). In this study, we characterized the TIG1 transducin b-like gene required for infectious growth and its interacting genes that are required for plant infection in this model phytopathogenic fungus. Tig1 homologs in yeast and mammalian cells are part of a conserved histone deacetylase (HDAC) transcriptional corepressor complex. The tig1 deletion mutant was nonpathogenic and defective in conidiogenesis. It had an increased sensitivity to oxidative stress and failed to develop invasive hyphae in plant cells. Using affinity purification and coimmunoprecipitation assays, we identified several Tig1-associated proteins, including two HDACs that are homologous to components of the yeast Set3 complex. Functional analyses revealed that TIG1, SET3, SNT1, and HOS2 were core components of the Tig1 complex in M. oryzae. The set3, snt1, and hos2 deletion mutants displayed similar defects as those observed in the tig1 mutant, but deletion of HST1 or HOS4 had no detectable phenotypes. Deletion of any of these core components of the Tig1 complex resulted in a significant reduction in HDAC activities. Our results showed that TIG1, like its putative yeast and mammalian orthologs, is one component of a conserved HDAC complex that is required for infectious growth and conidiogenesis in M. oryzae and highlighted that chromatin modification is an essential regulatory mechanism during plant infection.

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“…Foster, unpublished data), which contained a Magnaporthe ILV1 allele conferring sulfonylurea resistance, amplified from plasmid pCB1254 (Sweigard et al, 1998). The latter plasmid was a generous gift from Dr. James A.…”

Section: Identification Of the Pde1 Genementioning

confidence: 99%

PDE1 Encodes a P-Type ATPase Involved in Appressorium-Mediated Plant Infection by the Rice Blast Fungus Magnaporthe grisea

Balhadère

Talbot

2001

Plant Cell

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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. INTRODUCTIONOne of the principal reasons why pathogenic fungi are so successful at causing plant disease is their ability to penetrate the plant cuticle directly, often using specialized infection cells called appressoria (Mendgen et al., 1996). A wide variety of fungal pathogens form appressoria, and the development of these cells involves a complex morphogenetic program that results in rapid differentiation of a highly specialized structure (Dean, 1997). The rice blast fungus Magnaporthe grisea is an important pathogen of cultivated rice and has emerged as an experimental model for the study of plant infection processes (for reviews, see Howard and Valent, 1996;Hamer and Talbot, 1998). Magnaporthe develops dome-shaped appressoria, which form at the ends of germ tubes soon after spore germination on the leaf surface. Appressoria attach strongly to the leaf and then generate enormous turgor pressure (up to 8 MPa), which is used to rupture the plant cuticle (Howard et al., 1991). The turgor inside appressoria is generated by a rapid increase in intracellular glycerol levels, which is maintained by a specialized cell wall layer containing melanin (Howard and Ferrari, 1989;de Jong et al., 1997). If melanin biosynthesis is blocked, either by chemical intervention or mutation, then Magnaporthe is unable to penetrate the plant surface and cannot cause disease (Chida and Sisler, 1987;Chumley and Valent, 1990).How such enormous cellular turgor is translated into the substantial invasive force necessary to breach the plant cell wall is not clear, but it appears to involve polarization of the cytoskeleton to the point of infection and localized cell wall modification Howard, 1990, 1992;Bechinger et al., 1999). A narrow penetration hypha forms at t...

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Magnaporthe grisea Pathogenicity Genes Obtained Through Insertional Mutagenesis

Cited by 243 publications

References 35 publications

N-Glycosylation of Effector Proteins by an α-1,3-Mannosyltransferase Is Required for the Rice Blast Fungus to Evade Host Innate Immunity

N-Glycosylation of Effector Proteins by an α-1,3-Mannosyltransferase Is Required for the Rice Blast Fungus to Evade Host Innate Immunity

The Tig1 Histone Deacetylase Complex Regulates Infectious Growth in the Rice Blast Fungus Magnaporthe oryzae

PDE1 Encodes a P-Type ATPase Involved in Appressorium-Mediated Plant Infection by the Rice Blast Fungus Magnaporthe grisea

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