The Effect of UV-B Pretreatment on the Drought Response of Arabidopsis uvr8-2 Mutants

The effect of UV-B pretreatment on the drought response of Arabidopsis thaliana uvr8-2 mutants and the role of plant hormones in this process were investigated. The following results were obtained. Both morphological observation and physiological indicators showed that UV-B pretreatment significantly improved the drought adaptability of uvr8-2 mutants, which was consistent with the result of research on wild-type Landsberg erecta (Ler). The activities of antioxidant enzymes (SOD, POD, and CAT) were significantly increased upon UV-B pretreatment in Arabidopsis uvr8-2 mutants. The expression of antioxidant enzyme genes (POD and CAT) and the levels of plant hormones (ABA, JA and SA) also were increased. In addition, the degree of cell membrane damage was reduced. The fact that UV-B pretreatment induced the drought adaptability of uvr8-2 mutant implies that the signaling involved in the process is UVR8-independent, namely, the UV-B pretreatment induced drought adaptability by increasing plant hormones such as ABA, JA and SA to enhance the activity of antioxidant enzymes and antioxidant enzyme genes CAT and POD so as to alleviate the withering of leaves and the decreasing of relative water content under drought stress.