Identification and characterization of complete genome sequence of Alfalfa mosaic virus infecting Gynostemma pentaphyllum

Gynostemma pentaphyllum is a widely cultivated Chinese medicinal herb which has broad-spectrum activities. In this study, G. pentaphyllum plants with typical symptom of mosaic were found in Shaanxi province of China. The infection of Alfalfa mosaic virus (AMV) was identified by small RNA sequencing and confirmed by specific RT-PCR. We determined the complete genomic sequence of AMV-Gyn (GenBank No. MH332897-MH332899). The 3643nt RNA1 and 2598nt RNA2 encoded P1 protein of 1126 aa and P2 protein of 791 aa, respectively. The 2040nt RNA3 encoded MP of 300 aa and CP of 221 aa. Phylogenetic analysis based on sequences of RNA3 and CP gene clustered AMV-Gyn into phylogroup I with the closest evolutionary relationship with AMV-Manfredi (KC881010). No recombination event was detected. To our knowledge, this is the first report of a virus infecting G. pentaphyllum.