A novel narnavirus isolated from the wheat stripe rust fungus Puccinia striiformis f. sp. tritici.

The complete genome of a novel fungal virus, Puccinia striiformis narnavirus 1 (PsNV1), was sequenced and analyzed. The full-length cDNA sequence is 2340 bp in length with a GC content of 50.04%. PsNV1 contains a single open reading frame (ORF), which encodes a putative RNA-dependent RNA polymerase (RdRp) of 741 amino acids with a molecular mass of 81.8 kDa. RdRp phylogeny showed that PsNV1 grouped together with Fusarium poae narnavirus 1 (FpNV1) as a sister branch of narnaviruses, forming a distinct clade. The results of genome sequence comparisons and phylogenetic analysis indicate that PsNV1 is a new member in the genus Narnavirus. To our knowledge, this is the first report of a narnavirus genome sequence in the obligately parasitic fungus Puccinia striiformis f. sp. tritici.