Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, Zhejiang, China.
Plant J. 2024 Nov;120(3):901-909. doi: 10.1111/tpj.17023. Epub 2024 Sep 11.
Changes in plant morphology due to mechanical stimulation are known as thigmo responses. As climbing organs in plants, tendrils can sense mechanical stimulation after attaching to a support and then change their morphology within a short time. Here, the thigmo responses of cucumber tendril were investigated. Our results showed that mechanical stimulation stopped tendril elongation and that tendril length was determined by the distance from the support in cucumber. The mimicry touch treatment indicated that mechanical stimulation stopped tendril elongation by inhibiting cell expansion. RNA-seq data showed that three gibberellin (GA) metabolic genes (CsGA2ox3, CsCYP714A2, and CsCYP714A3) were upregulated in mechanically stimulated tendrils, and a major endogenous bio-active GA (GA) was reduced in mechanically stimulated tendrils. The roles of CsGA2ox3, CsCYP714A2, and CsCYP714A3 in GA deactivation were confirmed by their overexpression in transgenic Arabidopsis. Moreover, exogenous GA treatment recovered tendril elongation under mechanical stimulation, whereas exogenous uniconazole treatment inhibited tendril elongation without mechanical stimulation, suggesting that mechanical stimulation stopped tendril elongation, depending on GA deactivation. In summary, our results suggest that GA deactivation plays an important role in tendril thigmo response, ensuring that tendrils obtain a suitable final length according to their distance from the support in cucumber.
由于机械刺激而导致的植物形态变化被称为感震反应。作为植物的攀援器官，卷须在附着到支撑物后能够感知机械刺激，然后在短时间内改变其形态。在这里，研究了黄瓜卷须的感震反应。我们的结果表明，机械刺激停止了卷须的伸长，并且卷须的长度取决于黄瓜中离支撑物的距离。模拟触摸处理表明，机械刺激通过抑制细胞扩展来停止卷须的伸长。RNA-seq 数据显示，三种赤霉素（GA）代谢基因（CsGA2ox3、CsCYP714A2 和 CsCYP714A3）在机械刺激的卷须中上调，并且主要的内源性生物活性 GA（GA）在机械刺激的卷须中减少。通过在转基因拟南芥中过表达 CsGA2ox3、CsCYP714A2 和 CsCYP714A3，证实了它们在 GA 失活中的作用。此外，外源 GA 处理恢复了机械刺激下卷须的伸长，而外源烯效唑处理抑制了无机械刺激下卷须的伸长，这表明机械刺激停止卷须伸长取决于 GA 的失活。总之，我们的结果表明，GA 失活在卷须感震反应中起着重要作用，确保卷须根据其与黄瓜中支撑物的距离获得合适的最终长度。
