First report of Little cherry virus 1 and 2 in sweet cherry in Korea.
Sweet cherry, Prunus avium, is a minor fruit crop in Korea whose cultivation area is steadily increasing through regional specialization. Recently, Apple chlorotic leaf spot virus, Apple mosaic virus, Cherry necrotic rusty mottle virus (CNRMV), Cherry virus A (CVA), and Cherry green ring mottle virus have been reported in sweet cherries in Korea. In July 2016, eight samples from eight Napoleon cherry trees showing virus-like symptoms, such as vein chlorosis, protruding veins, and reddened leaves, were harvested in Gyeongju-si, Gyeongsangbuk-do, Republic of Korea. Total RNA was extracted from these symptomatic leaves and analysed by next-generation sequencing. BlastX and BlastN analyses of de novo assembled contigs confirmed the presence of Little cherry virus 1 (LChV-1), LChV-2, CVA and CNRMV. Reverse transcription-PCR assay revealed that all samples were infected by one (CVA, 2/8 samples), two (LChV-1 and CVA, 2/8), three (LChV-1, CVA, and CNRMV, 2/8), or four viruses (LChV-1, 2, CVA, and CNRMV, 2/8). This is thought to be the first report on the occurrence and sequences of LChV-1 and LChV-2 in sweet cherry trees in Korea.