Rice Glycosyltransferase Gene UGT85E1 Is Involved in Drought Stress Tolerance Through Enhancing Abscisic Acid Response

Abstract

Drought is one of the most important environmental constraints affecting plant growth and development and ultimately leads to yield loss. Uridine diphosphate (UDP)-dependent glycosyltransferases (UGTs) are believed to play key roles in coping with environmental stresses. In rice, it is estimated that there are more than 200 <i>UGT</i> genes. However, most of them have not been identified as their physiological significance. In this study, we reported the characterization of a putative glycosyltransferase gene <i>UGT85E1</i> in rice. <i>UGT85E1</i> gene is significantly upregulated by drought stress and abscisic acid (ABA) treatment. The overexpression of <i>UGT85E1</i> led to an enhanced tolerance in transgenic rice plants to drought stress, while the <i>ugt85e1</i> mutants of rice showed a more sensitive phenotype to drought stress. Further studies indicated that <i>UGT85E1</i> overexpression induced ABA accumulation, stomatal closure, enhanced reactive oxygen species (ROS) scavenging capacity, increased proline and sugar contents, and upregulated expression of stress-related genes under drought stress conditions. Moreover, when <i>UGT85E1</i> was ectopically overexpressed in Arabidopsis, the transgenic plants showed increased tolerance to drought as well as in rice. Our findings suggest that <i>UGT85E1</i> plays an important role in mediating plant response to drought and oxidative stresses. This work may provide a promising candidate gene for cultivating drought-tolerant crops both in dicots and monocots.