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Orchestration of plant development and defense by indirect crosstalk of SA and BR signaling through a transcription factor GhTINY2

更新时间:2021-05-03 19:56:04点击次数:285次字号:T|T
Sheng-hua Xiao, Qin Hu, Xiao-jun Zhang, Huan Si, Shi-ming Liu, Lin Chen, Kun Chen, Sabina Berne, Dao-jun Yuan, Keith Lindsey, Xian-long Zhang, Long-fu Zhu

Abstract

Salicylic acid (SA) and brassinosteroids (BRs) are well known to regulate diverse processes of plant development and stress responses, but the mechanisms by which these phytohormones mediate the growth-defense trade-off is largely unclear. In addition, little is known about the roles of DEHYDRATION RESPONSIVE ELEMENT BINDING (DREB) transcription factors, especially in biotic stress and plant growth. Here, we identified a cotton (Gossypium hirsutum) APETALA2/ETHYLENE RESPONSIVE FACTOR (AP2/ERF) gene GhTINY2 which is strongly induced by Verticillium dahliae. Overexpression of GhTINY2 in cotton and Arabidopsis (Arabidopsis thaliana) enhanced tolerance to V. dahliae, while knockdown of GhTINY2 expression increased cotton susceptibility to the pathogen. By directly activating WRKY51 expression, GhTINY2 promoted SA accumulation and SA signaling transduction. Moreover, GhTINY2-overexpressing cotton and Arabidopsis showed growth retardation, increased sensitivity to inhibitors of BR biosynthesis and downregulation of several BR-induced genes and upregulation of BR-repressed genes, while GhTINY2-RNAi cotton showed the opposite results. We further demonstrate that GhTINY2 negatively regulates BR signaling by interacting with BRASSINAZOLE-RESISTANT 1 (BZR1) and restraining its transcriptional activation of the expression of INDOLE-3-ACETIC ACID INDUCIBLE 19 (IAA19). These findings indicate that GhTINY2 fine-tunes the immunity-growth trade-off via an indirect crosstalk between WRKY51-mediated SA biosynthesis and BZR1-IAA19-regulated BR signaling.