The complete genomic sequence of Magnaporthe oryzae polymycovirus 1.

Abstract

A novel double-stranded RNA virus, designated as "Magnaporthe oryzae polymycovirus 1" (MoPmV1), was identified in Magnaporthe oryzae strain TM02. MoPmV1 has four dsRNA fragments, ranging from 1324 to 2401 bp in length. DsRNA1, 2, and 3 of MoPmV1 each possess a single large open reading frame (ORF), whereas dsRNA4 contains two ORFs. BLASTp analysis indicated that ORF1a, encoded by dsRNA1, shows 59.2% amino acid sequence identity with the RNA-dependent RNA polymerase (RdRp) of Beauveria bassiana polymycovirus 2; ORF2a, encoded by dsRNA2, shows 42.3% identity with the putative serine protease of Phaeoacremonium minimum tetramycovirus 1; ORF3a, encoded by dsRNA3, shows 40.6% identity with the methyltransferase of Aspergillus fumigatus tetramycovirus 1; ORF4a, encoded by dsRNA4, shows 41.7% identity with the proline-alanine-serine-rich (PASr) protein of Botryosphaeria dothidea virus 1, while ORF4b, encoded by dsRNA4, shows no significant similarity to any known proteins. Phylogenetic analysis of the RdRp domain indicated that MoPmV1 was grouped in a cluster with members of the genus Polymycovirus in the family Polymycoviridae. Based on these characteristics, MoPmV1 is a new member of the genus Polymycovirus in the family Polymycoviridae. This is the first report of a mycovirus of the family Polymycoviridae identified in rice blast fungus M. oryzae.