Li Zheng, Jia Fang, Li Lei-Lei, Kong Chui-Hua
Department of Ecology, College of Resources and Environmental Sciences, China Agricultural University, Beijing, China.
Pest Manag Sci. 2024 Aug 20. doi: 10.1002/ps.8378.
Plant chemical defense can be elicited by signaling chemicals. As yet, the elicitation is mainly known from volatile aboveground signals. Root-secreted belowground signals and their underlying mechanisms are largely unknown. This study examined a root-secreted signaling (-)-loliolide to trigger chemical defense in rice and wheat against pests by means of cocultivation and incubation experiments.
Wild-type Arabidopsis (WT) and its root exudates with (-)-loliolide induced the production of defensive metabolites of rice and wheat and reduced the performance of weeds, pathogens and herbivores, while a carotenoid-deficient mutant (szl1-1) and its root exudates without (-)-loliolide had no similar effects. However, the induction and reduction occurred in the szl1-1 root exudates by (-)-loliolide supplementation with the level equal to that of WT. RNA-sequencing analysis revealed a significant change in the transcript level of defense-related genes in rice exposure to (-)-loliolide. Furthermore, (-)-loliolide enhanced rice resistance against Rhizoctonia solani through changing reactive oxygen species (ROS) system, and mediating jasmonic acid, salicylic acid and abscisic acid biosynthesis.
Root-secreted signaling (-)-loliolide can trigger chemical defense in rice and wheat against their pests. Such perception-dependent chemical defenses provide an intriguing possibility for ecological pest management to increase crop productivity and sustainability. © 2024 Society of Chemical Industry.
植物化学防御可由信号化学物质引发。迄今为止，这种引发主要是通过地上挥发性信号得知的。根系分泌的地下信号及其潜在机制在很大程度上尚不清楚。本研究通过共培养和孵育实验，研究了根系分泌的信号物质（-）-黑麦草内酯能否触发水稻和小麦对害虫的化学防御。
野生型拟南芥（WT）及其含有（-）-黑麦草内酯的根系分泌物诱导了水稻和小麦防御性代谢产物的产生，并降低了杂草、病原体和食草动物的侵害能力，而类胡萝卜素缺陷型突变体（szl1-1）及其不含（-）-黑麦草内酯的根系分泌物则没有类似效果。然而，通过补充与WT水平相当的（-）-黑麦草内酯，szl1-1根系分泌物中出现了诱导和降低的现象。RNA测序分析显示，水稻暴露于（-）-黑麦草内酯时，防御相关基因的转录水平发生了显著变化。此外，（-）-黑麦草内酯通过改变活性氧（ROS）系统，介导茉莉酸、水杨酸和脱落酸的生物合成，增强了水稻对立枯丝核菌的抗性。
根系分泌的信号物质（-）-黑麦草内酯可触发水稻和小麦对害虫的化学防御。这种依赖感知的化学防御为生态害虫管理提供了一种有趣的可能性，以提高作物生产力和可持续性。© 2024化学工业协会。
