Salicylic acid‐activated BIN2 phosphorylation of TGA3 promotes Arabidopsis PR gene expression and disease resistance. (11th August 2022)

• Record Type: Journal Article
• Authors: Han, Qing; Tan, Wenrong; Zhao, Yuqing; Yang, Feng; Yao, Xiuhong; Lin, Honghui; Zhang, Dawei
• Is Part Of: EMBO journal. Volume 41:Number 19(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-08-11
• Subjects: BIN2 -- brassinosteroid -- plant immunity -- salicylic acid -- TGA3; Molecular biology -- Periodicals; 572.805
• DOI: 10.15252/embj.2022110682
• Languages: English
• ISSNs: 0261-4189

Abstract

Abstract: The plant defense hormone, salicylic acid (SA), plays essential roles in immunity and systemic acquired resistance. Salicylic acid induced by the pathogen is perceived by the receptor nonexpressor of pathogenesis‐related genes 1 (NPR1), which is recruited by TGA transcription factors to induce the expression of pathogenesis‐related (PR) genes. However, the mechanism by which post‐translational modifications affect TGA's transcriptional activity by salicylic acid signaling/pathogen infection is not well‐established. Here, we report that the loss‐of‐function mutant of brassinosteroid insensitive2 (BIN2) and its homologs, bin2‐3 bil1 bil2, causes impaired pathogen resistance and insensitivity to SA‐induced PR gene expression, whereas the gain‐of‐function mutant, bin2‐1, exhibited enhanced SA signaling and immunity against the pathogen. Our results demonstrate that salicylic acid activates BIN2 kinase, which in turn phosphorylates TGA3 at Ser33 to enhance TGA3 DNA binding ability and NPR1–TGA3 complex formation, leading to the activation of PR gene expression. These findings implicate BIN2 as a new component of salicylic acid signaling, functioning as a key node in balancing brassinosteroid‐mediated plant growth and SA‐induced immunity. Synopsis: How pathogen‐induced salicylic acid (SA)‐mediated expression of pathogenesis‐related (PR) genes is integrated into more long‐term signals is incompletely understood. Here, the brassinosteroid signaling kinase BIN2 is found involved in SA signaling via TGA transcription factor phosphorylation. BIN2 is an indispensable component of SA signaling; BIN2 interacts with and phosphorylates TGA3; SA‐induced phosphorylation of TGA3 by BIN2 promotes the interaction between TGA3 and NPR1, which enhances the transcriptional activity of TGA3; SA‐induced TGA3 phosphorylation positively regulates plant immunity. Abstract : Plant pathogen response signaling via salicylic acid and brassinosteroid‐mediated stress/developmental signals are more intertwined than previously thought.