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ARS Home » Northeast Area » Washington, D.C. » National Arboretum » Floral and Nursery Plants Research » Research » Publications at this Location » Publication #354503

Research Project: Detection, Identification, and Characterization of New and Emerging Viral and Bacterial Diseases of Ornamental Plants

Location: Floral and Nursery Plants Research

Title: A single nucleotide change in the overlapping MP and CP reading frames results in differences in symptoms caused by two isolates of Youcai mosaic virus

item JU, HYE-KYOUNG - Chungnam National University
item KIM, IK-HYUN - Chungnam National University
item HU, WEN-XING - Chungnam National University
item KIM, BORAM - Chungnam National University
item CHOI, GO-WOON - Chungnam National University
item KIM, JUNGKYU - Chungnam National University
item LIM, YONG PYO - Chungnam National University
item Domier, Leslie
item Hammond, John
item LIM, HYOUN-SUB - Chungnam National University

Submitted to: Archives of Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/22/2019
Publication Date: 3/28/2019
Citation: Ju, H., Kim, I., Hu, W., Kim, B., Choi, G., Kim, J., Lim, Y., Domier, L.L., Hammond, J., Lim, H. 2019. A single nucleotide change in the overlapping MP and CP reading frames results in differences in symptoms caused by two isolates of Youcai mosaic virus. Archives of Virology. 164(6):1553-1565.

Interpretive Summary: Plant viruses cause significant diseases of many crop plants, and cannot be effectively controlled by applications of agrochemicals. Control measures must instead either reduce the levels of virus entering the crop through sanitation and removal of disease reservoirs, or by breeding and selection of crop genotypes with resistance against the most prevalent viruses. In order to develop and utilize virus-resistant cultivars, the breeder and producer must have knowledge of the variability between viral isolates. Youcai mosaic virus is a virus affecting a range of horticultural crops, and emerging as a threat to crop productivity in Chinese cabbage in Korea. Two isolates of Youcai mosaic virus from Chinese cabbage that differ in pathogenicity were identified, and the factors causing the differences in symptom severity were analyzed. This knowledge will aid plant breeders in screening, selection and introduction of crop varieties with different resistance genes, allowing sustainable crop production without the need for added input.

Technical Abstract: Two isolates of Youcai mosaic virus (YoMV) were isolated and their full-length sequences were determined. Full-length infectious cDNA clones of each YoMV isolate were generated under control of dual T7 and 35S promoters for both in vitro transcript production and Agro-infiltration. Amino acid analysis demonstrated that they have just four amino acid differences, three in the RNA dependent RNA polymerase (RdRp) (V383I and M492I in 125kDa, T1245M in 182kDa); and one in the overlapping region of the movement protein (MP) and coat protein (CP) genes, affecting only the CP N-terminal domain (CP M17T). The two isolates show distinct severe and mild symptoms respectively in Nicotiana benthamiana. In order to identify the amino acid residues associated with symptom severity, chimeric constructs were generated between the two infectious YoMV clones, and their symptoms were compared to those induced by the parental isolates. The chimeric constructs demonstrated that the substitution of M17T in the CP N-terminal domain was responsible for the difference in symptom severity; and the M17T variation found to be unique amongst characterized YoMV isolates. A difference in potential post-translational modification of the CP may be responsible for the symptom differences.