Induction of a Cryphonectria parasitica cellobiohydrolase I gene is suppressed by hypovirus infection and regulated by a GTP-binding-protein-linked signaling pathway involved in fungal pathogenesis.

Extracellular cellulase activity is readily induced when the chestnut blight fungus Cryphonectria parasitica is grown on cellulose substrate as the sole carbon source. However, an isogenic C. parasitica strain rendered hypovirulent due to hypovirus infection failed to secrete detectable cellulase activity when grown under parallel conditions. Efforts to identify C. parasitica cellulase-encoding genes resulted in the cloning of a cellobiohydrolase (exoglucanase, EC gene designated chb-1. Northern blot analysis revealed an increase in cbh-1 transcript accumulation in a virus-free virulent C. parasitica strain concomitant with the induction of extracellular cellulase activity. In contrast, induction of cbh-1 transcript accumulation was suppressed in an isogenic hypovirus-infected strain. Significantly, virus-free C. parasitica strains rendered hypovirulent by transgenic cosuppression of a GTP-binding protein alpha subunit were also found to be deficient in the induction of cbh-1 transcript accumulation.
AuthorsP Wang, D L Nuss
JournalProceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 92 Issue 25 Pg. 11529-33 (Dec 5 1995) ISSN: 0027-8424 [Print] UNITED STATES
PMID8524797 (Publication Type: Comparative Study, Journal Article)
Chemical References
  • RNA Precursors
  • Glycoside Hydrolases
  • Cellulose 1,4-beta-Cellobiosidase
  • GTP-Binding Proteins
  • Amino Acid Sequence
  • Ascomycota (enzymology, genetics, pathogenicity, virology)
  • Base Sequence
  • Blotting, Southern
  • Cellulose 1,4-beta-Cellobiosidase
  • Cloning, Molecular
  • Enzyme Induction
  • GTP-Binding Proteins (metabolism)
  • Gene Expression Regulation, Fungal
  • Genes, Fungal
  • Glycoside Hydrolases (biosynthesis, genetics)
  • Molecular Sequence Data
  • RNA Precursors (biosynthesis)
  • Sequence Homology, Amino Acid
  • Signal Transduction
  • Suppression, Genetic
  • Transcription, Genetic
  • Trees (microbiology)
  • Virulence (genetics)

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