Mythimna separate herbivory primes Coix resistance in systemic leaves

Abstract Background Coix lacryma-jobi L. belongs to family Poaceae, is widely cultivated in tropic Asian countries for its nutritional and medicinal values. Coix is often threatened by lepidopteran such as Mythimna separata and Ostrinia furnacalis 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. Results 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, the response of primed systemic leaves was demonstrated via transcriptome analysis, which were up- or down-regulated comparing with the non-primed systemic leaves. Conclusions In this study, we first reported Mythimna separata simulated herbivory induced increased defense response in systemic leaves of Coix . Mythimna separate 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 .