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
Volume10
Issue8
Pagination984-93
Date Published1997 Nov
ISSN0894-0282
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
Abstract

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.

DOI10.1094/MPMI.1997.10.8.984
Alternate JournalMol. Plant Microbe Interact.
PubMed ID9353946
Grant ListAI40050 / AI / NIAID NIH HHS / United States