Detection, isolation, and characterization of the cucumber mosaic virus in Pseudostellaria heterophylla from Korea

Weeds play an important role in the survival of viruses and are potential inoculum sources of viral diseases for crop plants. In this study, specimens of Pseudostellaria heterophylla exhibiting symptoms of the cucumber mosaic virus (CMV) were collected in Bonghwa, Korea. The characteristics of the disease were described and leaf RNA was extracted and sequenced to identify the virus. Three CMV contigs were obtained and PCR was performed using specific primer pairs. RNA from positive samples exhibiting CMV leaf symptoms was amplified to determine the coat protein. A sequence comparison of the coat protein gene from the CMV BH isolate shared the highest nucleotide identity (99.2%) with the CMV ZM isolate. Phylogenetic analysis showed that CMV-BH belonged to subgroup IA and that the most closely-related isolate was CMV-ZM. All test plants used for the biological assay were successfully infected with CMV and exhibited CMV disease symptoms such as blistering, mosaic, and vein yellowing. To our knowledge, this is the first report of CMV infection in P. heterophylla from Korea.