Infectious cDNA clone of hypovirus CHV1-Euro7: a comparative virology approach to investigate virus-mediated hypovirulence of the chestnut blight fungus Cryphonectria parasitica.

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TitleInfectious cDNA clone of hypovirus CHV1-Euro7: a comparative virology approach to investigate virus-mediated hypovirulence of the chestnut blight fungus Cryphonectria parasitica.
Publication TypeJournal Article
Year of Publication1999
AuthorsChen, B, Nuss, DL
JournalJ Virol
Volume73
Issue2
Pagination985-92
Date Published1999 Feb
ISSN0022-538X
KeywordsAscomycota, Base Sequence, Cloning, Molecular, DNA, Complementary, DNA, Viral, Genome, Fungal, Molecular Sequence Data, Nuts, Phenotype, RNA Viruses, Virulence
Abstract

We report the construction of a full-length infectious cDNA clone for hypovirus CHV1-Euro7, which is associated with reduced virulence (hypovirulence) of the chestnut blight fungus Cryphonectria parasitica. Field strains infected with CHV1-Euro7 are more virulent and exhibit less severe phenotypic changes (hypovirulence-associated traits) than strains infected with the prototypic hypovirus CHV1-EP713, for which the first infectious cDNA clone was developed. These differences exist even though the two hypoviruses show extensive sequence identities: 87 to 93% and 90 to 98% at the nucleotide and amino acid levels, respectively. The relative contributions of viral and host genomes to phenotypic traits associated with hypovirus infection were examined by transfecting synthetic transcripts of the two hypovirus cDNAs independently into two different virus-free C. parasitica strains, EP155 and Euro7(-v). Although the contribution of the viral genome was clearly predominant, the final magnitude and constellation of phenotypic changes were a function of contributions by both genomes. The high level of sequence identity between the two hypoviruses also allowed construction of viable chimeras and mapping of the difference in symptom expression observed for the two viruses to the open reading frame B coding domain. Implications of these results for engineering enhanced biological control and elucidating the basis for hypovirus-mediated attenuation of fungal virulence are discussed.

Alternate JournalJ. Virol.
PubMed ID9882299
PubMed Central IDPMC103918
Grant ListGM55981 / GM / NIGMS NIH HHS / United States