基于代谢组学的黄芪根瘤象取食胁迫下黄芪应答机制研究

Gansu Province is China's critical production area of Chinese herbal medicines, Astragalus is one of the most important authentic medicinal materials in Gansu. With the enlarged planting area of astragalus, Sitona ophtalmicus Desbrochers (new records in China) has become predominant species in Astragalus membranaceus for excessive human intervention.The pest infest will caused the corresponding change of the chemical defense of astragalus, which also will affect the quality of the medicinal material. So, It is very necessary to study the response mechanism of the feeding threat on sitona ophthalmicus desbrochers. In this study,we use Astragalus membranaceus and Sitona ophtalmicus Desbrochers as research materials, using the feeding characteristics that larve feed on roots and adult feed on the leaves we will conduct aboveground and belowground feeding treatment. Nuclear magnetic resonance (NMR) and liquid chromatography-mass spectrometry(LC-MS) will conduct to investigate the changes of secondary chemicals and plant nutrients when Astragalus membranaceus was infected by Sitona ophtalmicus Desbrochers, then we will discuss the response mechanism of Astragalus membranaceus infested by Sitona ophtalmicus Desbrochers , reveal the complex relationship interactions between Astragalus membranaceus,aboveground adult and blowground laval. we will use bioassay to identify the secondary chemicals effective of reproduction and growth to Sitona ophtalmicus Desbrochers.Thus the response mechanism of Astragalus membranaceus infested by Sitona ophtalmicus Desbrochers will be revealed,finally ,the result will rich the coevolution between Chinese herbal medicines and pest in theory, and practically the result has important significance for the strategy of integrated pest management in traditional Chinese medicines.

甘肃是我国的中药材生产大省，黄芪是甘肃最主要的道地药材之一。随着黄芪栽植面积的逐年扩大，过分的人为干预使得黄芪根瘤象（我国新纪录害虫）上升为优势害虫种群。害虫取食胁迫会导致黄芪化学防御发生相应的改变，进而影响药材的品质形成，因此非常有必要开展黄芪根瘤象取食胁迫下黄芪的应答机制研究。本项目选取黄芪和黄芪根瘤象为研究对象，利用该虫幼虫取食根部、成虫取食叶部的为害特点，设置地上、地下不同取食处理，采取核磁代谢组学及液相色谱-质谱研究方法，分析不同取食胁迫下黄芪次生代谢物质、植物营养物质的变化，探讨不同取食压力下黄芪应答反应的内在机制，揭示黄芪-地上成虫-地下幼虫互作的复杂关系，并通过生物测定明确不同次生代谢物质对害虫生长发育的影响。研究结果有助于阐明黄芪根瘤象不同取食胁迫下黄芪应答反应的化学机制，理论上将丰富中药材与昆虫协同进化的内容，实践上将为黄芪及中药材害虫综合治理策略的完善提供科学依据。

黄芪根瘤象是甘肃省道地产区普遍发生主要为害黄芪的重要害虫，严重影响黄芪的产量、品质及药农的生产积极性。由于幼虫地下为害的特性，生产中缺乏科学有效的治理手段，只能依赖毒性高持效期长的化学药剂，黄芪根瘤象已经成为制约甘肃省黄芪产业健康发展的关键因子。昆虫取食胁迫会对植物次生代谢产生重要影响，而药用植物的次生代谢产物是其发挥药效的核心基础。因此，研究黄芪根瘤象取食胁迫对黄芪化学防御的影响具有重要的科学意义。.本项目以黄芪根瘤象和黄芪为研究对象，系统研究了黄芪对黄芪根瘤象取食胁迫的应答防御反应，并利用代谢组学及转录组学方法研究了黄芪根瘤象取食胁迫对黄芪次生代谢产物特别是药效物质的影响。.黄芪根瘤象取食胁迫诱导黄芪释放更多的防御性挥发物质，挥发性黄酮类和萜烯类物质的释放量显著高于健康植株。黄芪根瘤象取食诱导后黄芪叶片中的PAL、PPO活性显著提升，意味着黄芪体内用于化学防御的黄酮类、酚类物质合成增多。转录组分析显示，黄芪根瘤象的取食胁迫显著抑制了光合作用，取食72小时后，类黄酮和苯丙烷素合成和代谢相关基因在体内表达显著上调。KEGG分析表明，取食72小时后富集最显著的是异黄酮生物合成和多种次生代谢物质合成通路。黄芪根瘤象取食诱导激活了黄芪的茉莉酸合成和信号传导，对水杨酸的信号传导没有显著影响，取食72小时后萜烯类及苯丙烷类合成基因显著上调。代谢组分析显示，黄芪根瘤象取食胁迫后，叶片中酚酸类、醌类的防御物质增多，黄酮类防御物质减少，而在根系中，黄酮类和三萜皂苷的含量显著上升，氨基酸及衍生物下降较多。.应对不同的取食压力黄芪的防御策略并不一致，适度的黄芪根瘤象取食胁迫诱导了黄酮类及萜类次生代谢产物的基因表达显著上升，促进了黄芪药效物质的积累。本研究为黄芪根瘤象的综合治理提供了新的视角和科学的理论依据，同时也为其他药用植物的害虫治理提供借鉴与指导，丰富和完善了药用植物害虫综合治理策略。