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 a fungal pathogenesis

• Published in: Proceedings of the National Academy of Sciences - PNAS 1995-12, Vol.92 (25), p.11529-11533
• Main Authors: Wang, P. (University of Maryland, College Park, MD.), Nuss, D.L
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino acids; ARN MENSAJERO; ARN MESSAGER; Ascomycota - enzymology; Ascomycota - genetics; Ascomycota - pathogenicity; Ascomycota - virology; Base Sequence; Biology; Blotting, Southern; Cellulose 1,4-beta-Cellobiosidase; Cloning, Molecular; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; CRYPHONECTRIA PARASITICA; Enzyme Induction; Enzymes; EXPRESION GENICA; EXPRESSION DES GENES; Fungi; GENE; Gene expression regulation; Gene Expression Regulation, Fungal; GENES; Genes, Fungal; GENETICA; GENETIQUE; Glycoside Hydrolases - biosynthesis; Glycoside Hydrolases - genetics; GTP-Binding Proteins - metabolism; HIDROLASAS; HYDROLASE; hypovirus; Inductive reasoning; Infections; Molecular Sequence Data; NUCLEOTIDE; NUCLEOTIDOS; Parasitism; PODER PATOGENO; POUVOIR PATHOGENE; PROTEINAS AGLUTINANTES; PROTEINE DE LIAISON; Proteins; RNA Precursors - biosynthesis; SECUENCIA NUCLEICA; Sequence Homology, Amino Acid; SEQUENCE NUCLEIQUE; Signal Transduction; Sprains and strains; Suppression, Genetic; Transcription, Genetic; Trees - microbiology; Virulence; Virulence - genetics; Viruses
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.92.25.11529

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 3.2.1.91) gene designated cbh-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 CTP-binding protein alpha subunit were also found to be deficient in the induction of cbh-1 transcript accumulation