Wheat yellow mosaic virus (WYMV) is one of the most important soil-borne viral diseases of wheat. The disease can cause symptoms such as yellowing of leaves, growth retardation in spring, and reduced number of tillers, which not only seriously affects wheat yield but also affects its quality. When the onset is severe, it is easy to cause a 70%-80% reduction in production. Protected by the soil-borne vector Polymyxa graminis, the disease can exist in the susceptible soil for decades once infected, seriously endangering wheat production, and it is difficult to remove it with chemical agents and easily causes environmental pollution. At present, the most effective measure to control the disease is to breed and plant disease-resistant varieties, but the main resistance genes that can be used in the disease-resistant breeding are very rare.
Recently, the Kohei Mishina team of the Institute of Crop Sciences, National Agriculture and Food Research Organization and their collaborators published a research paper entitled " Wheat Ym2 originated from Aegilops sharonensis and confers resistance to soil-borne Wheat yellow mosaic virus infection to the roots" on PNAS. This study is the first to verify its function and analyze its evolutionary origin through positional cloning of the dominant anti-WYMV gene.
In this study, the WYMV-resistant gene Ym2 located on wheat 3BS chromosome was cloned by positional cloning. It was verified by transgenic complementation assay, bacterial artificial chromosome (BAC) library construction and sequencing, RNA in situ hybridization, enzyme-linked immunosorbent assay and other methods. At the same time, it was confirmed by evolutionary analysis that the gene was derived from a near relative of wheat, Aegilops sharonensis. The function of the gene in wheat roots has been determined through natural disease and artificial virus inoculation, that is, it can play a role in disease resistance at the source. Transferring the gene into susceptible wheat varieties by backcrossing method not only improves its disease resistance, but also increases its yield by 20%-50%. Therefore, this gene has important application value.
Reference:
Mishina, K.; et al. Wheat Ym2 originated from Aegilops sharonensis and confers resistance to soil-borne Wheat yellow mosaic virus infection to the roots. PNAS. 2023, 120 (11): e2214968120.
