Open AccessEvidence for common ancestry of a chestnut blight hypovirulence-associated double-stranded RNA and a group of positive-strand RNA plant viruses.
Author(s) -
Eugene V. Koonin,
Gil H. Choi,
Donald L. Nuss,
Roni Shapira,
James C. Carrington
Publication year - 1991
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.88.23.10647
Subject(s) - biology , chestnut blight , rna , rna silencing , genetics , potyvirus , rna polymerase , cryphonectria , rna dependent rna polymerase , virology , genome , polyproteins , phylogenetic tree , plant virus , virus , gene , rna interference , virulence , botany , fungus
Computer-assisted analysis of the putative polypeptide products encoded by the two open reading frames present in a large virus-like double-stranded RNA, L-dsRNA, associated with hypovirulence of the chestnut blight fungus, Cryphonectria parasitica, revealed five distinct domains with significant sequence similarity to previously described conserved domains within plant potyvirus-encoded polyproteins. These included the putative RNA-dependent RNA polymerase, RNA helicase, two papain-like cysteine proteases related to the potyvirus helper-component protease, and a cysteine-rich domain of unknown function similar to the N-terminal portion of the potyvirus helper-component protein. Phylogenetic trees derived from the alignment of the polymerase domains of L-dsRNA, a subset of positive-stranded RNA viruses, and double-stranded RNA viruses, using three independent algorithms, suggested that the hypovirulence-associated dsRNA and potyvirus genomes share a common ancestry. However, comparison of the organization of the conserved domains within the encoded polyproteins of the respective viruses indicated that the proposed subsequent evolution involved extensive genome rearrangement.