Abscisic acid receptors maintain abscisic acid homeostasis by modulating UGT71C5 glycosylation activity

• 作者: Yanlin Ma Jing Cao Qiaoqiao Chen Jiahan He Zhibin Liu Jianmei Wang Xufeng Li Yi Yang
• 来源期刊: 植物学报（英文版）
• 年，卷（期）: 2021,（3）
• 所属期刊栏目: Research Articles
• 页码范围: 543-552
• 页数: 10页
• 语种: 英文

摘要

Uridine diphosphate-glucosyltransferases (UGTs) maintain abscisic acid (ABA) homeostasis in Arabidopsis thaliana by converting ABA to abscisic acid-glucose ester (ABA-GE). UGT71C5 plays an im-portant role in the generation of ABA-GE. Abscisic acid receptors are crucial upstream components of the ABA signaling pathway, but how UGTs and ABA receptors function together to modulate ABA levels is unknown. Here, we demonstrated that the ABA re-ceptors RCAR12/13 and UGT71C5 maintain ABA homeostasis in Arabidopsis following rehydration under drought stress. Biochemical analyses show that UGT71C5 directly interacted with RCAR8/12/13 in yeast cells, and the interactions between UGT-71C5 and RCAR12/13 were enhanced by ABA treatment. Enzyme activity analysis showed that ABA-GE contents were significantly elevated in the presence of RCAR12 or RCAR13, suggesting that these ABA receptors enhance the activity of UGT71C5. Determination of the content of ABA and ABA-GE in Arabidopsis following rehydration under drought stress revealed that ABA-GE contents were significantly higher in Arabidopsis plants over-expressing RCAR12 and RCAR13 than in non-transformed plants and plants overexpressing RCAR11 following rehydration under drought stress. These observations suggest that RCAR12 and RCAR13 enhance the activity of UGT71C5 to glyco-sylate excess ABA into ABA-GE following rehydration under drought stress, representing a rapid mecha-nism for regulating plant growth and development.