Targeted disruption of a fungal G-protein beta subunit gene results in increased vegetative growth but reduced virulence.

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TitleTargeted disruption of a fungal G-protein beta subunit gene results in increased vegetative growth but reduced virulence.
Publication TypeJournal Article
Year of Publication1997
AuthorsKasahara, S, Nuss, DL
JournalMol Plant Microbe Interact
Date Published1997 Nov
KeywordsAmino Acid Sequence, Ascomycota, Base Sequence, Cloning, Molecular, Genes, Fungal, GTP-Binding Proteins, Molecular Sequence Data, Mutagenesis, Site-Directed, Nuts, Plant Diseases, Sequence Analysis, DNA, Sequence Homology, Amino Acid, Trees, Virulence

Targeted disruption of two G-protein alpha subunit genes in the chestnut blight fungus Cryphonectria parasitica revealed roles for the Gi alpha subunit CPG-1 in fungal reproduction, virulence, and vegetative growth. A second G alpha subunit, CPG-2, was found to be dispensable for these functions. We now report the cloning and targeted disruption of a C. parasitica G-protein beta subunit gene. The deduced amino acid sequence encoded by this gene, designated cpgb-1, was found to share 66.2, 65.9, and 66.7% amino acid identity with G beta homologues from human, Drosophila, and Dictyostelium origins, respectively, but only 39.7% identity with the Saccharomyces cerevisiae G beta homologue STE4 product. Low stringency Southern hybridization failed to detect any related G beta subunit genes in C. parasitica. Targeted disruption of cpgb-1 resulted in several of the changes previously reported to accompany disruption of the C. parasitica Gi alpha subunit gene cpg-1. These included very significant reductions in pigmentation, asexual sporulation, and virulence. In contrast to results obtained for Gi alpha gene disruption, the reduction in virulence resulting from the disruption of a G beta gene was accompanied by increased, rather than decreased, vegetative growth on synthetic medium. The relevance of these results to mechanisms of fungal virulence is considered.

Alternate JournalMol. Plant Microbe Interact.
PubMed ID9353946
Grant ListAI40050 / AI / NIAID NIH HHS / United States