拟南芥
赤霉素
茉莉酸
抑制因子
转录因子
分解代谢
拟南芥
茉莉酸
生物
突变体
细胞生物学
调节器
生物化学
信号转导
酶
基因
遗传学
作者
Lei Wang,Canrong Ma,Shuanghua Wang,Fei Yang,Yan Sun,Jinxiang Tang,Ji Luo,Jianqiang Wu
标识
DOI:10.1093/plphys/kiad556
摘要
Touch induces marked morphological changes in plants, including reduced rosette diameters and delayed flowering, a process called thigmomorphogenesis. Previous studies have revealed that thigmomorphogenesis in Arabidopsis (Arabidopsis thaliana) results from touch-induced accumulation of jasmonic acid (JA) and GIBBERELLIN 2-OXIDASE7 (GA2ox7) transcripts, which encode a gibberellin (GA) catabolism enzyme, leading to reduced levels of active GAs. However, the mechanisms underlying thigmomorphogenesis remain uncharacterized. Here we showed that touch induces ethylene (ET) production in Arabidopsis. After touch treatment, ET biosynthesis and signaling mutants exhibited even greater thigmomorphogenic changes and more decreased GA4 contents than did wild-type plants. Biochemical analysis indicated that the transcription factor ETHYLENE INSENSITIVE3 (EIN3) of the ET pathway binds to the promoter of GA2ox8 (encoding another GA 2-oxidase performing the same GA modification as GA2ox7) and represses GA2ox8 transcription. Moreover, MYC2, the master regulator of JA signaling, directly promoted GA2ox7 expression by binding the MYC2 promoter. Further genetic analysis suggested that the ET and JA pathways independently control the expression of GA2ox8 and GA2ox7, respectively. This study reveals that the ET pathway is a novel repressor of touch-induced thigmomorphogenesis and highlights that the ET and JA pathway converge on GA catabolism but play opposite roles to fine-tune GA4 content during thigmomorphogenesis.
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