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

Roni Shapira, Gil H. Choi, Bradley I. Hillman, Donald L. Nuss*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

77 Scopus citations

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 ∼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.

Original languageAmerican English
Pages (from-to)741-746
Number of pages6
JournalEMBO Journal
Volume10
Issue number4
StatePublished - 1991
Externally publishedYes

Keywords

  • Biological control
  • Defective RNAs
  • Mycovirus
  • Polymerase chain reaction

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