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An apple CIPK protein kinase targets a novel residue of AREB transcription factor for ABA‐dependent phosphorylation
Author(s) -
Ma QiJun,
Sun MeiHong,
Lu Jing,
Liu YaJing,
You ChunXiang,
Hao YuJin
Publication year - 2017
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.13013
Subject(s) - abscisic acid , phosphorylation , biology , transcription factor , gene , transgene , kinase , signal transduction , protein kinase a , abiotic stress , microbiology and biotechnology , genetics
Phytohormone abscisic acid (ABA) regulates many important processes in plants. It is a major molecule facilitating signal transduction during the abiotic stress response. In this study, an ABA‐inducible transcription factor gene, MdAREB2 , was identified in apple. Transgenic analysis was performed to characterize its function in ABA sensitivity. Overexpression of the MdAREB2 gene increased ABA sensitivity in the transgenic apple compared with the wild‐type (WT) control. In addition, it was found that the protein MdAREB2 was phosphorylated at a novel site Thr 411 in response to ABA. A yeast two‐hybridization screen of an apple cDNA library demonstrated that a protein kinase, MdCIPK22, interacted with MdAREB2. Their interaction was further verified with Pull Down and Co‐IP assays. A series of transgenic analyses in apple calli and plantlets showed that MdCIPK22 was required for ABA‐induced phosphorylation at Thr 411 of the MdAREB2 protein and enhanced its stability and transcriptional activity. Finally, it was found that MdCIPK22 increased ABA sensitivity in an MdAREB2‐dependent manner. Our findings indicate a novel phosphorylation site in CIPK‐AREB regulatory module for the ABA signalling pathway, which would be helpful for researchers to identify the functions of uncharacterized homologs in the future.