蚜虫取食priming诱导玉米系统性叶片长期抗虫能力的机理研究

Plants need to cope with various biotic and abiotic stress, plants can remember the first stress and then retrieve the stress memory, thus stimulating faster and stronger response when plants suffer the same stress again (priming, PRM). PRM is an important part of plant response to stress within a certain spatial and temporal scales, but the molecular mechanism of PRM is still unclear. It is generally believed that phytohormones and epigenetics may regulate PRM. Maize (Zea mays L.), as an important crop, is threatened by insects, especially aphids. The bird cherry oat aphid (Rhopalosiphum padi) is one of the most detrimental aphids on maize plant. Recently, we found that R. padi pre-infestation on maize local leaf (PRM) increased long-lasting resistance of the systemic leaf against R. padi, which presents a strong PRM effect. In this proposal, we intend to use maize (A188) and R. padi as research objects, furthermore, we plan to analyze phytohormones, secondary insect-resistant metabolites, transcriptional regulation and epigenetic control (DNA methylation) of the systemic leaf which is systemically primed by R. padi on local leaf, combined analysis with maize transgenic lines lacking salicylic acid, jasmonic acid, and benzoxazinoids (NahG, irAOC, and bx2) , respectively, thus dissecting the intrinsic regulation mechanism of this process through multi-omics and genetics integration analysis. In addition, we will analyze whether the PRM effect is conserved among different maize inbred lines. This work will not only provide vital information for maize response to insect feeding in a certain spatial and temporal scales, but also supply theoretical support for agricultural pest control and insect-resistant crop breeding.

植物面临多种生物和非生物胁迫，其可“记忆”首次胁迫，为再次类似胁迫做准备，以作出更快、更强烈的应答，即priming（PRM）。PRM是植物对逆境时空响应的重要部分，但PRM的分子机制仍然缺乏研究。目前一般认为植物激素途径和表观遗传学都可能调控PRM。玉米是重要的粮食作物，但蚜虫等虫害严重危害其生长。我们前期研究发现禾谷缢管蚜取食玉米叶片后，其它未被取食（系统性）叶片的长期抗禾谷缢管蚜能力大为增强，呈现出强烈的PRM响应。本研究拟从激素、抗虫代谢物、转录和表观遗传（DNA甲基化）等四个维度，结合玉米缺失水杨酸、茉莉酸和丁布的转基因株系（NahG、irAOC和bx2），关联多重组学和遗传学等方法，解析禾谷缢管蚜取食诱导的PRM增强玉米系统叶片长期抗虫性的分子机制，并分析玉米不同自交系的PRM效应是否存在保守性。本研究为玉米调控抗虫响应提供重要信息，也为农业虫害防控及抗虫作物育种提供理论支撑。

Priming（PRM）是植物对逆境时空响应的重要部分，但PRM的分子机制仍然缺乏研究。本研究以重要的粮食作物玉米为研究对象，从激素、抗虫代谢物、和转录等三个维度，解析禾谷缢管蚜取食诱导的PRM增强玉米系统叶片抗虫性的分子机制。本研究的主要结论如下：.1. 通过表型实验证明，禾谷缢管蚜取食本地叶片（PRM）以后，可增强系统叶片抵御斜纹夜蛾的能力；.2. 禾谷缢管蚜PRM本地叶片以后，当斜纹夜蛾取食系统叶片时，与对照组相比，系统叶片中的水杨酸、茉莉酸和茉莉酸异亮氨酸含量显著升高，以更高效地应对斜纹夜蛾的侵害并增强系统性叶片抗虫能力;.3. 禾谷缢管蚜PRM本地叶片，增强了系统叶片中丁布类物质含量上升的能力，进而增强系统叶片抵御斜纹夜蛾取食的能力；.4. 转录组分析表明，禾谷缢管蚜PRM本地叶片以后，当斜纹夜蛾取食系统叶片时，与对照组相比，差异表达基因主要集中在应对刺激和胁迫等过程；.5. 进一步对丁布类物质合成基因、萜烯类合成基因和抗虫激素茉莉酸合成和代谢基因的表达进行分析，发现无论蚜虫是否取食本地叶片，系统叶片中抗逆相关基因的表达均受到相似的诱导调控；.6. 从转录组数据中筛选到四个转录因子，可能是参与响应系统性抗虫的关键候选转录因子；.本研究为玉米抗虫响应的研究提供重要信息，也为深入理解Priming在植物应对生物胁迫过程中作用提供理论支撑，具有重要的现实指导意义。