A high temperature responsive UDP-glucosyltransferase gene OsUGT72F1 enhances heat tolerance in rice and Arabidopsis.

Abstract

Key message: OsUGT72F1 enhances heat tolerance in plants by improving ROS scavenging and modifying multiple metabolic pathways, under the regulation of transcription factors OsHSFA3 and OsHSFA4a. High temperature is one of the most critical environmental constraints affecting plant growth and development, ultimately leading to yield losses in crops such as rice (Oryza sativa L.). UDP (uridine diphosphate)-dependent glycosyltransferases (UGTs) are believed to play crucial roles in coping with environmental stresses. However, the functions for the vast majority of UGTs under high temperature stress remain largely unknown. In this study, we isolated and characterized a high temperature responsive UDP-glycosyltransferase gene OsUGT72F1 in rice. Our findings demonstrated that overexpression of OsUGT72F1 enhanced heat-stress tolerance, while the mutant plants displayed a sensitive phenotype under the same stress conditions. Ectopic expression of OsUGT72F1 in Arabidopsis thaliana also conferred improved heat tolerance to the plants. Further investigation revealed that OsUGT72F1 reduced the generation of reactive oxygen species (ROS) and boosted the activity of antioxidant enzymes, thereby alleviating oxidative damage under heat-stress conditions. Moreover, transcriptomic analysis indicated that the action of OsUGT72F1 leads to the upregulation of multiple metabolic pathways including phenylpropanoid biosynthesis, zeatin biosynthesis, and flavonoid biosynthesis. In addition, the upstream regulatory mechanism of the OsUGT72F1 gene has been identified. We found that the transcription factors OsHSFA3 and OsHSFA4a can bind to the OsUGT72F1 promoter and enhance its transcription level. Together, this study revealed that the glycosyltransferase gene OsUGT72F1 plays a vital role in the adaptive adjustment of high temperature stress in plants, revealing a new heat tolerance pathway and providing a promising gene candidate for the breeding of heat-resistant crop varieties.