Abscisic acid (ABA) is an important plant hormone that plays a crucial role in response to abiotic stresses. It is well-known that the level of ABA will be dynamically regulated under stress conditions, however, the regulatory mechanism of ABA homeostasis remains largely unknown. In this study, we isolated and characterized a putative UDP-glycosyltransferase (UGT3) in rice, which is proven to be stress-induced and involved in ABA dynamic change. Our data demonstrated that overexpression of the glycosyltransferase gene UGT3 enhanced drought and salt stress tolerance of the transgenic rice. However, ugt3 mutant exhibited sensitive phenotypes under stresses. The ectopic expression of UGT3 in Arabidopsis also enhanced the plant tolerance to drought and salt stresses. Overexpression of UGT3 in rice increased endogenous ABA level and showed hypersensitive phenotype to exogenous ABA treatment at both germination and post-germination stages. Further studies demonstrated that UGT3 elevated activities of the antioxidant enzymes and reduced the production of reactive oxygen species to control the oxidative burst under stress conditions. Taken together, this work reveals that glycosyltransferase UGT3 can cope with the environmental challenges through a possible interactive network of ABA, ROS and antioxidants under abiotic stresses.

脱落酸（ABA）是一种重要的植物激素，在应对非生物胁迫中起着至关重要的作用。众所周知，在胁迫条件下ABA水平会受到动态调节，然而，ABA稳态的调节机制在很大程度上仍是未知的。在这项研究中，我们分离并表征了水稻中一种推定的 UDP-糖基转移酶 (UGT3)，该酶被证明是胁迫诱导的并参与 ABA 动态变化。我们的数据表明，糖基转移酶基因UGT3 的过表达增强了转基因水稻的干旱和盐胁迫耐受性。然而，ugt3突变体在压力下表现出敏感的表型。UGT3的异位表达拟南芥还增强了植物对干旱和盐胁迫的耐受性。水稻中UGT3 的过表达增加了内源 ABA 水平，并在萌发和萌发后阶段对外源 ABA 处理表现出超敏表型。进一步的研究表明，UGT3 提高了抗氧化酶的活性并减少了活性氧的产生，以控制应激条件下的氧化爆发。总之，这项工作表明，糖基转移酶 UGT3 可以通过 ABA、ROS 和抗氧化剂在非生物胁迫下可能的交互网络来应对环境挑战。