STRESS INDUCED FACTOR 2 Regulates Arabidopsis Stomatal Immunity through Phosphorylation of the Anion Channel SLAC1

• Published in: The Plant cell 2020-07, Vol.32 (7), p.2216-2236
• Main Authors: Chan, Ching, Panzeri, Dario, Okuma, Eiji, Tõldsepp, Kadri, Wang, Ya-Yun, Louh, Guan-Yu, Chin, Tzu-Chuan, Yeh, Yu-Hung, Yeh, Hung-Ling, Yekondi, Shweta, Huang, You-Huei, Huang, Tai-Yuan, Chiou, Tzyy-Jen, Murata, Yoshiyuki, Kollist, Hannes, Zimmerli, Laurent
• Format: Article
• Language: English
• Subjects: Abscisic Acid - metabolism; Abscisic Acid - pharmacology; Animals; Arabidopsis - microbiology; Arabidopsis - physiology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - immunology; Arabidopsis Proteins - metabolism; Disease Resistance - physiology; Female; Histone Deacetylases - genetics; Histone Deacetylases - immunology; Histone Deacetylases - metabolism; Membrane Proteins - genetics; Membrane Proteins - immunology; Membrane Proteins - metabolism; Mutation; Oocytes - physiology; Phosphorylation; Plant Diseases - immunology; Plant Diseases - microbiology; Plant Immunity - drug effects; Plant Stomata - immunology; Plant Stomata - metabolism; Plants, Genetically Modified; Protein Kinases - metabolism; Protein Serine-Threonine Kinases - metabolism; Repressor Proteins - genetics; Repressor Proteins - immunology; Repressor Proteins - metabolism; Serine - metabolism; Xenopus
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.19.00578

SIF2 is critical for Arabidopsis (Arabidopsis thaliana) resistance to bacteria by regulating stomatal immunity, belongs to the FLS2/BAK1 immunity receptor complex, and phosphorylates the anion channel SLAC1. Abstract Upon recognition of microbes, pattern recognition receptors (PRRs) activate pattern-triggered immunity. FLAGELLIN SENSING2 (FLS2) and BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1 (BAK1) form a typical PRR complex that senses bacteria. Here, we report that the kinase activity of the malectin-like receptor-like kinase STRESS INDUCED FACTOR 2 (SIF2) is critical for Arabidopsis (Arabidopsis thaliana) resistance to bacteria by regulating stomatal immunity. SIF2 physically associates with the FLS2-BAK1 PRR complex and interacts with and phosphorylates the guard cell SLOW ANION CHANNEL1 (SLAC1), which is necessary for abscisic acid (ABA)-mediated stomatal closure. SIF2 is also required for the activation of ABA-induced S-type anion currents in Arabidopsis protoplasts, and SIF2 is sufficient to activate SLAC1 anion channels in Xenopus oocytes. SIF2-mediated activation of SLAC1 depends on specific phosphorylation of Ser 65. This work reveals that SIF2 functions between the FLS2-BAK1 initial immunity receptor complex and the final actuator SLAC1 in stomatal immunity.