Open AccessA Virulence-Associated, 6.4-kb, Double-Stranded RNA from Rhizoctonia solani Is Phylogenetically Related to Plant Bromoviruses and Electron Transport Enzymes
Author(s) -
Jianhua Jian,
Dilip K. Lakshman,
S. M. Tavantzis
Publication year - 1998
Publication title -
molecular plant-microbe interactions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.565
H-Index - 153
eISSN - 1943-7706
pISSN - 0894-0282
DOI - 10.1094/mpmi.1998.11.7.601
Subject(s) - biology , orfs , virulence , helicase , open reading frame , gene , peptide sequence , genetics , rna
We have recently shown that acquisition of a 6.4-kb, double-stranded (ds) RNA (M1) by hyphal anastomosis is associated with enhanced vigor and virulence, whereas its removal by hyphal tipping correlates with diminished virulence in the plant-pathogenic basidiomycete Rhizoctonia solani. The M1 dsRNA is not encapsidated by a typical nucleocapsid, has a circular and/or concatemeric form, and is associated with the mitochondrial and cytosolic fractions. M1 possesses six open reading frames (ORFs) the longest of which (ORF 2) is located on the (+) strand, and encodes a putative polypeptide consisting of 1,747 amino acids or 199.4 kDa. This polypeptide has a significant amino acid sequence similarity, including six conserved helicase domains and an ATP/GTP binding motif, with the 1A protein of broad bean mottle virus (BBMV) and other bromoviruses. ORF 5, which is located on the (-) strand of M1 and is complementary to a region of ORF 2, codes for a putative polypeptide that has a significant amino acid sequence similarity with the cytochrome c oxidase assembly factor. This complementarity provides direct evidence suggesting that the long-standing hypothesis of viruses evolving from cellular genes may be valid.