Molecular characterization of a novel amalgavirus infecting lilium spp. in China

A novel plant virus with a double-stranded (ds) RNA genome was detected in Lilium spp. in China by high-throughput sequencing and tentatively named "lily amalgavirus 2" (LAV2). The genomic RNA of LAV2 is 3432 nucleotides (nt) in length and contains two open reading frames (ORFs) that putatively encode a '1 + 2' fusion protein of 1053 amino acids (aa), generated by a '+1' programmed ribosomal frameshift (PRF). ORF1 encodes a putative 386-aa protein of unknown function, and ORF2 overlaps ORF1 by 350 nt and encodes a putative 783-aa protein with conserved RNA-dependent RNA polymerase (RdRp) motifs. The '+1' ribosomal frameshifting motif, UUU_CGN, which is highly conserved among amalgaviruses, is also found in LAV2. Sequence analysis showed that the complete genome shared 46.04%-51.59% nucleotide sequence identity with those of members of the genus Amalgavirus and had the most similarity (51.59% sequence identity) to lily amalgavirus 1 (accession no. OM782323). Phylogenetic analysis based on RdRp amino acid sequences showed that LAV2 clustered with members of the genus Amalgavirus. Overall, our data suggest that LAV2 is a new member of the genus Amalgavirus.