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A viral gene confers hypovirulence‐associated traits to the chestnut blight fungus.
Author(s) -
Choi G.H.,
Nuss D.L.
Publication year - 1992
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1992.tb05077.x
Subject(s) - chestnut blight , biology , cryphonectria , virulence , mycovirus , rna silencing , conidiation , gene , genetics , rna , fungus , rna interference , botany , rna polymerase
A viral double‐stranded (ds)RNA associated with reduced virulence (hypovirulence) and the accompanying biological control of the chestnut blight fungus, Cryphonectria parasitica, was shown recently to contain two contiguous coding domains designated ORF A and ORF B. We report here that transformation of an isogenic virulent, dsRNA‐free C. parasitica strain with a cDNA copy of ORF A conferred traits similar to those exhibited by the dsRNA‐containing hypovirulent strain: characteristics included reduced pigmentation, reduced laccase accumulation and suppressed conidiation. However virulence was not reduced, indicating an apparent uncoupling of associated traits from hypovirulence. These results establish a direct cause and effect relationship between a viral dsRNA genetic element present in a hypovirulent C. parasitica strain and specific phenotypic traits. They demonstrate further that these traits are not the result of a general reaction of the fungus to the presence of the replicating viral RNA, but are caused by a specific viral coding domain.