Molecular characterization of a novel non-segmented double-stranded RNA mycovirus isolated from Penicillium citrinum strain RCEF7060.

Penicillium citrinum is a commonly occurring filamentous fungus with a worldwide distribution. However, no sequence data for viruses in P. citrinum have been reported. Here, we characterized a novel dsRNA virus from the hospital indoor air fungal strain P. citrinum RCEF 7060, which we have named "Penicillium citrinum non-segmented dsRNA virus 1" (PcNRV1). The genome of PcNRV1 dsRNA is 2,895 bp in length and contains two open reading frames encoding a protein with an unknown function in ORF1 and a putative RNA-dependent RNA polymerase (RdRp) in ORF2. Sequence comparisons and phylogenetic analysis showed that PcNRV formed a well-supported independent clade together with members of the proposed genus "Unirnavirus" and was most closely related to Penicillium miczynskii RNA virus 1 (PmRV1), with 76.45% amino acid sequence identity in the RdRp. Thus, PcNRV1 is a novel non-segmented dsRNA mycovirus belonging to the proposed genus "Unirnavirus" and is the first characterized viral sequence from P. citrinum.