PCE | 吲哚启动的防御信号增强茶树抗虫性
2020-11-07 作者: admin 来源: 未知 已阅读次
Abstract
Upon herbivore attack, plants emit herbivore‐induced plant volatiles (HIPVs). HIPVs can prime defenses and resistance of intact plants. However, how HIPVs are decoded and translated into functional defense responses is not well understood, especially in long‐lived woody plants. Here, we investigated the impact of the aromatic HIPV indole on defense‐related early signaling, phytohormone accumulation, secondary metabolite biosynthesis and herbivore resistance in tea plants. We find that tea plants infested with tea geometrid caterpillars release indole at concentrations > 450 ng*h‐1. Exposure to corresponding doses of synthetic indole primes the expression of early defense genes involved in calcium (Ca2+) signaling, MPK signaling and jasmonate biosynthesis. Indole exposure also primes the production of jasmonates and defense‐related secondary metabolites. These changes are associated with higher herbivore resistance of indole‐exposed tea plants. Chemical inhibition of Ca2+ and jasmonate signaling provides evidence that both are required for indole‐mediated defense priming and herbivore resistance. Our systematic assessment of the impact of indole on defense signaling and deployment shows that indole acts by boosting Ca2+ signaling, resulting in enhanced jasmonate‐dependent defense and resistance in a woody plant. Our work extends the molecular basis of HIPV‐induced defense priming from annual plants to an economically important tree species.
一旦发生害虫攻击，植物会释放出虫害诱导的植物挥发物（HIPV）。HIPV可以启动未受害植物的防御反应。然而，HIPV是如何被解码并转化为功能性防御反应的机制还并不清楚，尤其是在多年生的木本植物中。在这里，我们研究了芳香族HIPV吲哚对茶树防御相关的早期信号、植物激素积累、次生代谢产物生物合成和茶树的草食抗性的影响。我们发现，茶树在遭受茶尺蠖危害时，其释放吲哚的浓度可以大于450 ng/h。用相应剂量的吲哚处理茶树会引发包括钙信号、MPK信号和茉莉酸合成等在内的植物早期防御途径相关基因的表达，而且也会引发茉莉酸盐和防御相关次级代谢物的产生。这些变化与吲哚释放茶树具有较高的草食害虫抗性有关。化学抑制钙离子和茉莉酸信号发现这两种物质都是吲哚介导的防御启动和抗虫性所必需的。吲哚通过增强钙离子信号传导增强了木本植物的茉莉酸依赖的防御和抗性反应。我们的工作将HIPV诱导防御启动的分子基础从一年生植物扩展到了重要的经济作物。
责任编辑：千鹤茶苗