Evidence for a role of the regulator of G-protein signaling protein CPRGS-1 in Galpha subunit CPG-1-mediated regulation of fungal virulence, conidiation, and hydrophobin synthesis in the chestnut blight fungus Cryphonectria parasitica.

Printer-friendly versionPrinter-friendly versionPDF versionPDF version
TitleEvidence for a role of the regulator of G-protein signaling protein CPRGS-1 in Galpha subunit CPG-1-mediated regulation of fungal virulence, conidiation, and hydrophobin synthesis in the chestnut blight fungus Cryphonectria parasitica.
Publication TypeJournal Article
Year of Publication2004
AuthorsSegers, GC, Regier, JC, Nuss, DL
JournalEukaryot Cell
Volume3
Issue6
Pagination1454-63
Date Published2004 Dec
ISSN1535-9778
KeywordsAmino Acid Sequence, Blotting, Western, Cloning, Molecular, DNA Mutational Analysis, DNA Primers, Fungal Proteins, Gene Deletion, Membrane Proteins, Molecular Sequence Data, Mutation, Phenotype, Phylogeny, Plasmids, Polymerase Chain Reaction, Protein Structure, Tertiary, Reverse Transcriptase Polymerase Chain Reaction, RGS Proteins, RNA, RNA, Messenger, RNA, Ribosomal, 18S, Sequence Homology, Amino Acid, Signal Transduction, Sordariales, Time Factors, Transcription, Genetic
Abstract

We previously reported that the chestnut blight fungus Cryphonectria parasitica expresses at least three G-protein alpha subunits and that Galpha subunit CPG-1 is essential for regulated growth, pigmentation, sporulation, and virulence. We now report the cloning and characterization of a C. parasitica regulator of G-protein signaling (RGS) protein, CPRGS-1. The phylogenetic relationship of CPRGS-1 to orthologs from other fungi was inferred and found to be generally concordant with species relationships based on 18S ribosomal sequences and on morphology. However, Hemiascomycotine RGS branch lengths in particular were longer than for their 18S sequence counterparts, which correlates with functional diversification in the signaling pathway. Deletion of cprgs-1 resulted in reduced growth, sparse aerial mycelium, and loss of pigmentation, sporulation, and virulence. Disruption of cprgs-1 was also accompanied by a severe posttranscriptional reduction in accumulation of CPG-1 and Gbeta subunit CPGB-1 and severely reduced expression of the hydrophobin-encoding gene cryparin. The changes in phenotype, cryparin expression, and CPGB-1 accumulation resulting from cprgs-1 gene deletion were also observed in a strain containing a mutationally activated copy of CPG-1 but not in strains containing constitutively activated mutant alleles of the other two identified Galpha subunits, CPG-2 and CPG-3. Furthermore, cprgs-1 transcript levels were increased in the activated CPG-1 strain but were unaltered in activated CPG-2 and CPG-3 strains. The results strongly suggest that CPRGS-1 is involved in regulation of Galpha subunit CPG-1-mediated signaling and establish a role for a RGS protein in the modulation of virulence, conidiation, and hydrophobin synthesis in a plant pathogenic fungus.

DOI10.1128/EC.3.6.1454-1463.2004
Alternate JournalEukaryotic Cell
PubMed ID15590820
PubMed Central IDPMC539028
Grant ListGM55981 / GM / NIGMS NIH HHS / United States