SCFAtPP2-B11 modulates ABA signaling by facilitating SnRK2.3 degradation in Arabidopsis thaliana

• Published in: PLoS genetics Vol. 13; no. 8; p. e1006947
• Main Authors: Cheng, Chunhong, Wang, Zhijuan, Ren, Ziyin, Zhi, Liya, Yao, Bin, Su, Chao, Liu, Liu, Li, Xia
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.08.2017; Public Library of Science (PLoS)
• Subjects: Abiotic stress; Abscisic acid; Abscisic Acid - pharmacology; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Biology and Life Sciences; Cullin; Developmental biology; Drought; Droughts; F-box protein; F-Box Proteins - genetics; F-Box Proteins - metabolism; Gene Expression Regulation, Plant; Kinases; Laboratories; Phosphatase; Phosphorylation; Plant Growth Regulators - pharmacology; Plant sciences; Promoter Regions, Genetic; Proteasome 26S; Proteasome Endopeptidase Complex - genetics; Proteasome Endopeptidase Complex - metabolism; Protein phosphatase; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - metabolism; Proteins; Proteolysis; Regulation; Research and Analysis Methods; RNA, Ribosomal - genetics; Seed germination; Seeds; Signal Transduction; SKP Cullin F-Box Protein Ligases - genetics; SKP Cullin F-Box Protein Ligases - metabolism; Software; Stress response; Transcription factors; Ubiquitin; Ubiquitin-protein ligase; Beijing China; China
• ISSN: 1553-7404; 1553-7390; 1553-7404
• DOI: 10.1371/journal.pgen.1006947

The phytohormone abscisic acid (ABA) is an essential part of the plant response to abiotic stressors such as drought. Upon the perception of ABA, pyrabactin resistance (PYR)/PYR1-like (PYL)/regulatory components of ABA receptor (RCAR) proteins interact with co-receptor protein phosphatase type 2Cs to permit activation Snf1-related protein kinase2 (SnRK2) kinases, which switch on ABA signaling by phosphorylating various target proteins. Thus, SnRK2 kinases are central regulators of ABA signaling. However, the mechanisms that regulate SnRK2 degradation remain elusive. Here, we show that SnRK2.3 is degradated by 26S proteasome system and ABA promotes its degradation. We found that SnRK2.3 interacts with AtPP2-B11 directly. AtPP2-B11 is an F-box protein that is part of a SKP1/Cullin/F-box E3 ubiquitin ligase complex that negatively regulates plant responses to ABA by specifically promoting the degradation of SnRK2.3. AtPP2-B11 was induced by ABA, and the knockdown of AtPP2-B11 expression markedly increased the ABA sensitivity of plants during seed germination and postgerminative development. Overexpression of AtPP2-B11 does not affect ABA sensitivity, but inhibits the ABA hypersensitive phenotypes of SnRK2.3 overexpression lines. These results reveal a novel mechanism through which AtPP2-B11 specifically degrades SnRK2.3 to attenuate ABA signaling and the abiotic stress response in Arabidopsis.