Data_Sheet_1_Exogenous Application of Gallic Acid Induces the Direct Defense of Tea Plant Against Ectropis obliqua Caterpillars.docx

Gallic acid (GA), an important polyphenolic compound in the plant, is a well-known antioxidant, antihyperglycemic, and anti-lipid peroxidative agent. Recently, GA treatment exhibited ameliorative effects on plants in response to some abiotic stresses. However, the elicitation effect of GA on plant defense against herbivorous insects has not yet been reported. In this study, we found that the exogenous application of GA induced the direct defense of tea plant (Camellia sinensis) against tea geometrid (Ectropis obliqua) larvae, through activating jasmonic acid (JA) signaling and phenylpropanoid pathways. These signaling cascades resulted in the efficient induction of several defensive compounds. Among them, astragalin, naringenin, and epigallocatechin-3-gallate were the three of the most active anti-feeding compounds. However, the exogenous GA treatment did not affect the preference of E. obliqua female moths and larval parasitoid Apanteles sp. Our study suggests that GA may serve as an elicitor that triggers a direct defense response against tea geometrid larvae in tea plants. This study will help to deepen the understanding of the interaction between plants and phytophagous insects and also provide theoretical and technical guidance for the development of plant defense elicitors.

葛根酸（GA），作为植物中一种重要的多酚类化合物，已知具有抗氧化、抗高血糖和抗脂质过氧化等作用。近期研究表明，GA处理对植物应对某些非生物胁迫表现出改善效果。然而，关于GA对植物抵御食草昆虫防御诱发的效应尚未见报道。本研究发现，外源施用GA通过激活茉莉酸（JA）信号传导和苯丙烷类代谢途径，直接诱导茶树（Camellia sinensis）对茶尺蠖（Ectropis obliqua）幼虫的防御反应。这些信号级联反应导致了几种防御化合物的有效诱导。其中，黄芪苷、柚皮素和表没食子儿茶素-3-没食子酸酯是三种最有效的抗食性化合物。然而，外源GA处理并未影响茶尺蠖雌蛾和幼虫寄生蜂Apanteles sp.的偏好。本研究表明，GA可能作为一种诱导剂，触发茶树对茶尺蠖幼虫的直接防御反应。该研究有助于加深对植物与食植性昆虫之间相互作用的了解，并为植物防御诱导剂的研发提供理论和技术指导。