KEGG pathway of the DEGs in NP1-C.

Coix lacryma-jobi L. belongs to family Poaceae, is widely cultivated in tropical Asian countries for its nutritional and medicinal values. Coix is often threatened by lepidopteran such as Mythimna separata during its life cycle, resulting in severe yield reduction. Insect feeding can trigger defense signaling and increased defense responses in many other crops, yet little is known about whether simulated armyworm feeding on Coix leaves could induce anti-herbivory responses and whether armyworm feeding could activate priming in systemic leaves. In this study, Mythimna separata simulated herbivory elicited increased jasmonic acid (JA) level, JA-Ile (JA-isoleucine conjugate) and altered transcriptome in the Coix leaves. Meanwhile, M. separata simulated herbivory in local leaves primed the systemic leaves for increased accumulation of jasmonic acid and enhanced resistance to M. separata. Consistently, transcriptome analysis showed the systemic leaves were primed, which were up- or down-regulated comparing with the non-primed systemic leaves. In this study, we first reported Mythimna separata simulated herbivory induced increased defense response in leaves of Coix, also Mythimna separata herbivory primed Coix resistance in systemic leaves. This study provides new insight into the regulation of defense responses of Coix against M. separata and the ecological function of priming in Coix.薏苡 (Coix lacryma-jobi L.) 隶属于禾本科 (Poaceae)，因其兼具营养与药用价值，在亚洲热带国家被广泛栽培。薏苡在整个生长周期中常遭受粘虫 (Mythimna separata) 这类鳞翅目昆虫的为害，进而导致产量严重下降。已有研究表明，昆虫取食可触发诸多作物的防御信号通路并增强防御响应，但目前学界对以下两个问题尚不清楚：模拟粘虫取食薏苡叶片是否能诱导抗植食性防御反应，以及粘虫取食是否能激活系统叶片的启动作用 (priming)。本研究发现，模拟粘虫取食可提升薏苡叶片内茉莉酸 (JA)、茉莉酸-异亮氨酸结合物 (JA-Ile) 的含量，并改变其转录组 (transcriptome) 谱。同时，局部叶片的模拟粘虫取食可致敏系统叶片，使其茉莉酸积累量提升，并增强对粘虫的抗性。与之相符的是，转录组分析结果显示，与未致敏的系统叶片相比，致敏后的系统叶片基因表达存在显著上调或下调差异。本研究首次报道了模拟粘虫取食可诱导薏苡叶片产生增强的防御响应，且粘虫取食可在系统叶片中致敏薏苡的防御抗性。本研究为解析薏苡对抗粘虫的防御调控机制，以及启动作用在薏苡中的生态功能提供了全新视角。