Molecular characterization of a novel non-segmented double-stranded RNA mycovirus isolated from the phytopathogenic fungus Lasiodiplodia pseudotheobromae.

In this study, we isolated a novel mycovirus from Lasiodiplodia pseudotheobromae strain YY-1, which we named "Lasiodiplodia pseudotheobromae mycovirus 1" (LpMyV1). The complete genome of LpMyV1 is 2877 bp in length and contains two non-overlapping open reading frames (ORF1 and ORF2). ORF1 encodes a putative protein of 316 amino acids with a molecular weight of 34.1 kDa that shares similarity with the coat proteins of several mycoviruses. ORF2 encodes a protein of 561 amino acids with a molecular weight of 63.2 kDa that contains a conserved RNA-dependent RNA polymerase (RdRp) domain. BLASTp results showed that the RdRp of LpMyV1 shares the highest similarity with those of non-segmented dsRNA viruses. A multiple sequence alignment and phylogenetic analysis indicated that LpMyV1 is a new member of the proposed genus "Unirnavirus". This is the first report of a mycovirus from L. pseudotheobromae.