A novel narnavirus from the entomogenous fungus Beauveria bassiana Vuillemin

Abstract

Abstract A novel positive single stranded RNA (+ssRNA) mycovirus Beauveria bassiana splipalmivirus 1 (BbSpV1) was identified from Beauveria bassianaVuillemin, an entomogenous fungi used for pest biological control worldwide. The genome of the virus was determined by metagenomic sequencing, RT-PCR, and RACE cloning. Four open reading frames (ORF) distribute on three +ssRNA fragments, with the lengths of 2149 bp, 2133 bp, and 1266 bp, respectively. The ssRNA1 encodes a RNA dependent RNA polymerase (RdRp) motif, with 645 -amino-acid (aa) (73.07 kDa), sharing the highest identity of 66.61% to that of Plasmopara viticola lesion associated narnavirus 5 (PVaNarn5) according to a BLASTx analysis. The ssRNA2 encodes another predicted RdRp motif, with 640 aa (73.66 kDa), sharing the highest identity of 62.09% to that of Suillus luteus narnavirus 4 (SlNV4) according to a BLASTx analysis. The ssRNA3 encodes two proteins with undetermined function, which are 175 aa (19.91 kDa) and 154 aa (16.58 kDa), respectively. The virus peculiarly consists of two divided RdRp domains, possessing typical characteristic consistent with the splipalmiviruses. This virus is the first record of the splipalmivirus identified from B. bassiana.