First report of Cucumber mosaic virus infection of peanut (Arachis hypogaea) in South Korea.
In South Korea, only 3 viruses, i.e. Bean common mosaic virus (BCMV), Peanut mottle virus (PeMoV) and Peanut stripe virus (PSV), have been reported to infect peanut or groundnut (A. hypogaea). As part of a survey for viral infection of peanuts conducted in June 2013, seven peanut leaf samples showing mosaic and yellowing mosaic symptoms and two nonsymptomatic peanut leaf samples were collected from the Chilgok-gun region, Gyeonsangbuk-do Province, South Korea. All 9 total RNA samples were used for reverse transcription-PCR with specific primer sets for Alfalfa mosaic virus (AMV), Cucumber mosaic virus (CMV), Peanut clump virus (PCV), BCMV, PSV, and PeMoV. Among 7 symptomatic tested samples, 5 samples were coinfected by CMV and BCMV, one sample was infected with CMV, BCMV, and PeMoV, while one sample was infected with CMV only. The 2 asymptomatic samples were found infected with both CMV and BCMV. To confirm the presence of the gene for coat protein (CP) of CMV isolated from the single-infection sample, designated as CMV-CG, a primer pair designed at conserved regions of the published CMV sequence from 13 isolates from the NCBI was used to perform RT-PCR. Sequence comparison of CP gene of CG isolate showed 94.2% (subgroup IA: D10538), 97.4% (subgroup IB: AB008777), and 78.4% (subgroup II: M21464) nt identities with CP sequences of other CMV isolates. Host range determination of the CMV-CG isolate revealed that all test plants (Chenopodium amaranticolor [C. giganteum], Nicotiana tabacum, N. glutinosa, N. benthamiana, N. clevelandii, Lycopersicon esculentum, Capsicum annuum and A. hypogaea) showed 100% nt sequence identities with the inoculum. This is thought to be the first report of a CMV infection of the peanut plant in South Korea.