Identification of UV-B-induced microRNAs in wheat.

MicroRNAs (miRNAs) play critical roles in post-transcriptional gene regulation and act as important endogenous regulators to various stressors. Ultraviolet-B (UV-B) radiation is a major factor influencing crop growth and development. In this study, we isolated a novel wheat miRNA, named Tae-miR6000, and confirmed its expression diversity after UV-B treatments. Additionally, using the Northern blotting technique, we found that six miRNAs were highly responsive to UV-B stress in wheat. Of these six miRNAs, miR159, miR167a, and miR171 were significantly upregulated, and the remaining three miRNAs were downregulated, at different time points after UV-B treatment. This result indicates that miRNAs may be involved in the regulation of targets after induction by UV-B stress. Furthermore, promoter analysis of the UV-B-responsive miRNA genes revealed some light-relevant cis-elements, such as the I-box and G-box. Taken together, the results of this study suggest that wheat miRNAs play important roles in the response to UV-B stress.