Characterization of hypovirus-derived small RNAs generated in the chestnut blight fungus by an inducible DCL-2-dependent pathway.

The disruption of one of two dicer genes, dcl-2, of the chestnut blight fungus Cryphonectria parasitica was recently shown to increase susceptibility to mycovirus infection (G. C. Segers, X.

Evidence that RNA silencing functions as an antiviral defense mechanism in fungi.

The role of RNA silencing as an antiviral defense mechanism in fungi was examined by testing the effect of dicer gene disruptions on mycovirus infection of the chestnut blight fungus Cryphonectria parasitica. C. parasitica dicer-like genes dcl-1 and dcl-2 were cloned and shown to share a high level of predicted amino acid sequence identity with the corresponding dicer-like genes from Neurospora crassa [Ncdcl-1 (50.

Microarray analysis of Cryphonectria parasitica Galpha- and Gbetagamma-signalling pathways reveals extensive modulation by hypovirus infection.

Using an established spotted cDNA microarray platform, the nature of changes in the transcriptional profiles of 2200 unique genes from the chestnut blight fungus Cryphonectria parasitica in response to the absence of either the Galpha subunit CPG-1 or the Gbeta subunit CPGB-1 has been explored. It is reported that 216 transcripts were altered in accumulation in the Deltacpg-1 strain and 163 in the Deltacpgb-1 strain, with a considerable overlap (100 genes) that were changed in both cases. Of note, these commonly altered transcripts were changed in the same direction in every instance, thus suggesting a considerable redundancy in pathway control or extensive crosstalk.

Analysis of altered G-protein subunit accumulation in Cryphonectria parasitica reveals a third Galpha homologue.

Heterotrimeric G-proteins mediate many responses of eukaryotic cells to external stimuli and have been shown to be important for fungal pathogenicity. In this study, we explored the accumulation of G-protein subunits of the chestnut blight fungus, Cryphonectria parasitica, in mutant strains deleted for one or more putative partner subunits. Using a series of extraction buffers and immunoblot end-point dilution analysis, we established a convenient method to assess the relative abundance of these membrane-associated proteins.

Constitutively activated Galpha negatively regulates virulence, reproduction and hydrophobin gene expression in the chestnut blight fungus Cryphonectria parasitica.

Disruption of the gene encoding Galpha subunit cpg-1 in the chestnut blight fungus Cryphonectria parasitica reduces growth and pigmentation and abolishes reproduction and virulence. We now report the consequences of mutations designed to constitutively activate (Q204-L and R178-C) CPG-1-mediated signaling. Introduction of cpg-1-QL or cpg-1-RC into wild type, Deltacpg-1 and Deltacpgb-1 (Gbeta) mutant strains resulted in a dominant phenotype characterized by a complete absence of aerial hyphae, pigmentation, conidia production and virulence.