Characterization of two Cucumber mosaic virus isolated from Solanum mammosum and Nicotiana affinis

Two Cucumber mosaic virus (CMV) isolates, CMV-NA from Nicotiana affinis, and CMV-SM from Solanum mammosum (nipple fruit plant) inducing mild and severe systemic mosaic symptoms, respectively, on tobacco (Nicotiana tabacum cv. Xanthi-nc), were characterized on the basis of their nucleotide and amino acid sequences of RNA3, serology and host ranges. The complete nucleotide sequencing of RNA3s of CMV-NA and CMV-SM has been done. Multiple alignment analysis of the nucleotide sequences of RNA3 of the 5′noncoding region and amino acid sequences of the CP and MP revealed that, CMV-NA and CMV-SM belong to subgroup I. CMV-NA induced systemic infection on Cryptotaenia japonica and caused severe leaf malformation, but CMV-SM could not infect this plant. N. occidentalis inoculated mechanically with CMV-SM developed mild mosaic symptoms, while CMV-NA was unable to induce systemic infection on this plant. Thus, C. japonica and N. occidentalis are strain specific hosts for CMV-NA and CMV-SM, respectively. Raphanus sativus cv. Akidumari and Phaseolus vulgaris demonstrated to be non-host plants of CMV-NA and CMV-SM. This is the first report of a CMV strain infecting N. affinis in the field.