Complete genome sequence of a novel endornavirus isolated from Ceratobasidium AG-Bo strain LC-JK-2.

Here, we report the identification of a positive-sense single-stranded RNA virus from Ceratobasidium AG-Bo strain LC-JK-2, designated as "Rhizoctonia cerealis alphaendornavirus 2" (RcAEV-2). The complete genome sequence of this virus was determined and found to be 15,244 nt in length with a GC content of 39%. The genome contains a single open reading frame (ORF) encoding an RNA-dependent RNA polymerase (RdRp) of 4974 amino acids (aa) with a predicted molecular weight of 547.14 kDa. BLASTp results showed that the RdRp of RcAEV-2 had the highest amino acid sequence similarity to that of Ceratobasidium endornavirus A (YP_009310113.1). Phylogenetic analysis revealed that RcAEV-2 exhibited the closest evolutionary relationship to Ceratobasidium endornavirus A within the genus Alphaendornavirus, forming a distinct clade separate from other virus families. Thus, RcAEV-2 has been identified as a new member of the genus Alphaendornavirus within the family Endornaviridae.