Differences in isolates of tomato yellow leaf curl virus in tomato fields located in Daejeon and Chungcheongnam-do between 2017 and 2018

Authors: OH, JUNE-PYO - Chungnam National University; CHOI, GO-WOON - Chungnam National University; KIM, JUNGKYU - Chungnam National University; OH, MIN-HEE - Chungnam National University; KIM, KANG-HEE - Chungnam National University; PARK, JONGSEOK - Chungnam National University; Domier, Leslie; Hammond, John; LIM, HYOUN-SUB - Chungnam National University

Submitted to: Korean Journal of Agricultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2019
Publication Date: 9/12/2019
Citation: Oh, J., Choi, G., Kim, J., Oh, M., Kim, K., Park, J., Domier, L.L., Hammond, J., Lim, H. 2019. Differences in isolates of tomato yellow leaf curl virus in tomato fields located in Daejeon and Chungcheongnam-do between 2017 and 2018. Korean Journal of Agricultural Science. 46(3):507-517. https://doi.org/10.7744/kjoas.20190034.
DOI: https://doi.org/10.7744/kjoas.20190034

Interpretive Summary: Virus infections reduce both yield and quality in many different crops, and environmental factors and changes in cropping practices, invasive insect vectors, and accompanying viruses may result in different disease problems. Tomato yellow leaf curl virus (TYLCV) and its whitefly vector were not known to occur in Korea before 2008 and 2005, respectively, but have assumed increasing importance in the production of tomato and other vegetable crops in Korea. A survey of tomato crops in 2017 identified TYLCV or another whitefly-transmitted virus in mixed infections with tomato mosaic virus, which was previously the most common virus infecting tomato in Korea. In a 2018 survey, TYLCV was the only virus found in symptomatic tomato plants; however the virus isolates differed from that found in 2017; thus the virus appears to have become established in Korea, but in agreement with prior reports, there have likely been multiple introductions of TYLVC into Korea from different geographic origins. This information will be important to farmers, plant breeders, and extension agents to guide the future management of the disease through identification and elimination of potential reservoirs of both the virus and the vector between crop cycles.

Technical Abstract: To follow up on a 2017 survey of tomato virus diseases, samples with virus-like symptoms were collected from the same areas (Buyeo-gun, Chungchungnam-Do and Daejeon, Korea) in 2018. Whereas in 2017 mixed infections of tomato mosaic virus with either tomato yellow leaf curl virus (TYLCV) or tomato chlorosis virus were detected (Choi et al., 2018), only TYLCV was detected in symptomatic samples in 2018. TYLCV amplicons of c.777 bp representing the coat protein (CP) coding region were cloned from TYLCV positive samples, and sequence data showed 97.17% to 98.84% nucleotide and 98.45% to 99.22% amino acid identity with the 2017 Buyeo-gun isolate (MG787542), which had the highest amino acid (aa) sequence identity of up to 99.2% with four 2018 Buyeo-gun sequences (MK521830, MK521833. MK521834, MK521835). The lowest aa sequence identity of 98.45% was shown with 2018 Daejeon isolate (MK521836); the distance between Buyeo-gun and Daejeon is about 45 km. Phylogenetic analysis indicated that the currently reported CP sequences are most closely related to Korean sequences from Masan (HM130912), Goseong (JN680149), Busan (GQ141873), and Boseong (GU325634) in the ‘Japan’ cluster of TYLCV isolates, and distinct from ‘China’ cluster isolates from Nonsan (GU325632), Jeonju (HM130913) and Jeju (GU325633, HM130914). Our survey data from 2017 and 2018 suggest that TYLCV has become established in Korea, and may be spread by the whitefly vectors from weed reservoirs within the farm environment.