UCK2 and infection: In this study, GhUKL4 showed significant expression differences between the resistant and the susceptible cultivar after inoculation with V. dahliae, and showed up-regulated expression after intection in the resistant inbred lines, but down-regulated expression in the susceptible inbred lines (Figure 2), which is in accordance with the results in previous study, showing that the expression of uridine kinase genes in rice was significantly upregulated after infection with X. oryzae pv.