The contribution of defective RNAs to the complexity of viral-encoded double-stranded RNA populations present in hypovirulent strains of the chestnut blight fungus Cryphonectria parasitica.

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TitleThe contribution of defective RNAs to the complexity of viral-encoded double-stranded RNA populations present in hypovirulent strains of the chestnut blight fungus Cryphonectria parasitica.
Publication TypeJournal Article
Year of Publication1991
AuthorsShapira, R, Choi, GH, Hillman, BI, Nuss, DL
JournalEMBO J
Volume10
Issue4
Pagination741-6
Date Published1991 Apr
ISSN0261-4189
KeywordsBase Sequence, Chromosome Deletion, Cloning, Molecular, Models, Molecular, Molecular Sequence Data, Nucleic Acid Conformation, Oligonucleotide Probes, Open Reading Frames, Phenotype, Plant Viruses, Plants, Polymerase Chain Reaction, RNA, Double-Stranded, RNA, Fungal, RNA, Viral, Virulence, Xylariales
Abstract

Hypovirulent strain EP713 of the chestnut blight fungus Cryphonectria (Endothia) parasitica harbors a family of viral encoded double-stranded (ds) RNAs thought to be responsible for the hypovirulence phenotype. These include L-dsRNA, described in the accompanying paper (Shapira et al., 1991); several prominent species in the estimated size range of 8 to 10 kb, referred to here as M-dsRNAs; and several smaller species designated S-dsRNAs which range in size from approximately 0.6 to 1.7 kb. The characterization of the M- and S-dsRNA species is the subject of this report. Results from polymerase chain reaction mapping and molecular hybridization analysis indicate that the M- and S-dsRNA species are internally deleted forms of L-dsRNA. Three different S-dsRNA species were cloned and sequenced. Each species contained a single deletion breakpoint and retained either 149, 155 or 156 bp of the terminus corresponding to the 5'-end of the coding strand and 440, 447 or 449 bp of the other terminus. Two of the S-dsRNA species contained, within the boundaries of the breakpoint, additional sequence information consisting of 42 bp or 95 bp that appeared to be unrelated to the L-dsRNA sequence. These results demonstrate that defective RNAs contribute significantly to the complexity of dsRNA populations found in hypovirulent strains of C. parasitica and provide a first approximation of the location of cis-acting signals involved in their replication.

Alternate JournalEMBO J.
PubMed ID2009855
PubMed Central IDPMC452711