Genomic characterization of a novel cytorhabdovirus infecting Ixeris denticulata in China

Abstract

Ixeris denticulata is a perennial herbal plant with important medical and economic value. In this study, a novel rhabdovirus from I. denticulata with leaf curling and mottle symptoms was identified through next-generation sequencing and molecular cloning approaches. Based on the host species and properties of this virus, it was tentatively named "Ixeris denticulata-associated rhabdovirus" (IdaRV). IdaRV has a negative-sense RNA genome that is 12,705 nucleotides in length and has five open reading frames (ORFs) in the order 3'-nucleoprotein -phosphoprotein -movement protein -matrix protein -large RNA-dependent RNA polymerase-5'. Pairwise sequence comparisons showed that IdaRV had 42.2-53.0% sequence identity to members of the genera Cytorhabdovirus, Varicosavirus, Betanucleorhabdovirus, Gammanucleorhabdovirus, Dichorhavirus, and Alphanucleorhabdovirus in the subfamily Betarhabdovirinae. BLASTp searches indicated that putative products of ORF1, ORF2, ORF3, ORF4, and ORF5 of IdaRV are most closely related to those of rudbeckia virus 1 (RudV1, GenBank accession number ON185810), with 32.1%, 21.3%, 52.4%, 37.6%, and 57.1% amino acid sequence identity, respectively, at the protein level. Phylogenetic analysis showed that IdaRV forms a smaller branch with RudV1, which belongs to the genus Cytorhabdovirus. These results establish IdaRV as a novel rhabdovirus in the genus Cytorhabdovirus of the family Rhabdoviridae.