Group C MAP kinases phosphorylate MBD10 to regulate ABA‐induced leaf senescence in Arabidopsis

• Published in: The Plant journal : for cell and molecular biology 2024-06, Vol.118 (6), p.1747-1759
• Main Authors: Li, Yangdan, Kamiyama, Yoshiaki, Minegishi, Fuko, Tamura, Yuki, Yamashita, Kota, Katagiri, Sotaro, Takase, Hinano, Otani, Masahiko, Tojo, Ryo, Rupp, Gabrielle E., Suzuki, Takamasa, Kawakami, Naoto, Peck, Scott C., Umezawa, Taishi
• Format: Article
• Language: English
• Subjects: Abscisic acid; Abscisic Acid - metabolism; Abscisic Acid - pharmacology; Arabidopsis; Arabidopsis - genetics; Arabidopsis - physiology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Environmental stress; Gene Expression Regulation, Plant; Kinases; leaf senescence; Leaves; MAPK; MBD10; Mitogen-Activated Protein Kinases - genetics; Mitogen-Activated Protein Kinases - metabolism; Phenotypes; Phosphorylation; Plant Growth Regulators - metabolism; Plant hormones; Plant Leaves - genetics; Plant Leaves - metabolism; Plant Leaves - physiology; Plant Senescence - genetics; Plants; Plants, Genetically Modified; Senescence
• ISSN: 0960-7412; 1365-313X; 1365-313X
• DOI: 10.1111/tpj.16706

SUMMARY Abscisic acid (ABA) is a phytohormone that promotes leaf senescence in response to environmental stress. We previously identified methyl CpG‐binding domain 10 (MBD10) as a phosphoprotein that becomes differentially phosphorylated after ABA treatment in Arabidopsis. ABA‐induced leaf senescence was delayed in mbd10 knockout plants but accelerated in MBD10‐overexpressing plants, suggesting that MBD10 positively regulates ABA‐induced leaf senescence. ABA‐induced phosphorylation of MBD10 occurs in planta on Thr‐89, and our results demonstrated that Thr‐89 phosphorylation is essential for MBD10's function in leaf senescence. The in vivo phosphorylation of Thr‐89 in MBD10 was significantly downregulated in a quadruple mutant of group C MAPKs (mpk1/2/7/14), and group C MAPKs directly phosphorylated MBD10 in vitro. Furthermore, mpk1/2/7/14 showed a similar phenotype as seen in mbd10 for ABA‐induced leaf senescence, suggesting that group C MAPKs are the cognate kinases of MBD10 for Thr‐89. Because group C MAPKs have been reported to function downstream of SnRK2s, our results indicate that group C MAPKs and MBD10 constitute a regulatory pathway for ABA‐induced leaf senescence. Significance Statement ABA‐induced leaf senescence is one of the important processes involved in the translocation of nutrients from one tissue to another under drought stress. We found that group C MAP kinases phosphorylate MBD10 in response to ABA, and the two proteins constitute a regulatory pathway for ABA‐induced leaf senescence in Arabidopsis.