Molecular characterization of a novel gammapartitivirus infecting the fungus Nigrospora oryzae.

ABSTRACT

Here, we identified a new mycovirus infecting the phytopathogenic fungus Nigrospora oryzae, which we have designated "Nigrospora oryzae partitivirus 2" (NoPV2). The genome of NoPV2 consists of two dsRNA segments (dsRNA 1 and dsRNA 2), measuring 1771 and 1440 bp in length, respectively. dsRNA 1 and dsRNA 2 each contain a single open reading frame (ORF) that encodes the RNA-dependent RNA polymerase (RdRp) and capsid protein (CP), respectively. A BLASTp search showed that the RdRp of NoPV2 had significant sequence similarity to the RdRps of other partitiviruses, including Nigrospora sphaerica partitivirus 1 (75.61% identity) and Magnaporthe oryzae partitivirus 1 (67.53% identity). Phylogenetic analysis revealed that NoPV2 is a new member of the genus Gammapartitivirus in the family Partitiviridae. This study provides important information for understanding the diversity of mycoviruses in N. oryzae.