Molecular characterization of a novel deltaflexivirus from the plant-pathogenic fungus Neopestalotiopsis nebuloides strain N-7.

The full genome sequence of a positive-sense (+) single-stranded (ss) RNA virus, which we have named "Neopestalotiopsis nebuloides deltaflexivirus 1" (NnDFV1), from Neopestalotiopsis nebuloides strain N-7 was sequenced and analyzed. The NnDFV1 genome is 7,719 nucleotides in length with a GC content of 49%, excluding the poly(A) tail, and contains a large open reading frame (ORF1) and three smaller ORFs (2-4). ORF1 encodes a replication-associated polyprotein (RP) consisting of three conserved domains: viral methyltransferase (Mtr), viral helicase (Hel), and RNA-dependent RNA polymerase (RdRp), whereas ORFs 2-4 encode three hypothetical proteins (18-20 kDa). Phylogenetic analysis showed that NnDFV1 formed a distinct clade together with Pestalotiopsis deltaflexivirus 1 (PDFV1), which is a new member of the genus Deltaflexivirus within the family Deltaflexiviridae. This is the first report of a novel deltaflexivirus found in the phytopathogenic fungus Neopestalotiopsis nebuloides.