独脚金内酯通过木质素调控菊花抗蚜性的分子机制研究

菊花是我国十大传统名花和世界四大切花之一，观赏、经济价值极高。蚜虫是严重为害菊花的最主要害虫，化学防治困难，已成为限制我国菊花产业化发展的瓶颈。木质素作为防御蚜虫取食的第一道有效防线，受其合成基因及转录因子调控。项目组先前发现新型植物激素独角金内酯抑制菊花木质素合成，促进蚜虫取食，而其调控木质素合成从而改变菊花抗蚜性的分子机制尚不清楚。为此，本申请拟借助qRT-PCR、RT-PCR、RACE技术发掘、克隆独脚金内酯调控的抗蚜性相关木质素合成关键基因；通过酵母单杂交、DNA结合蛋白亲和捕获技术发掘关键合成基因上游转录因子；借助超表达、基因沉默反向遗传学技术鉴定目标基因功能和抗蚜性；采用间苯三酚染色、紫外自发荧光、NMR、透射电镜检测木质素含量、单体成分及细胞壁厚度。揭示独脚金内酯借助木质素调控菊花抗蚜性的分子机制及新功能，为菊花蚜虫科学防治及减药栽培提供依据，具重要的科学意义与实践价值。

Chrysanthemum, one of ten traditional Chinese famous flowers and one of four cut flowers over the world, of high ornamental and economic values, is extremely susceptive to aphid. Aphid causes direct damage to plants via draining the plant nutrition and indirect damage via spreading virus and pathogen disease. Chemical application fails to control the aphid efficiently, and aphid infestation has become a bottleneck of chrysanthemum industry. Lignin is the main composition of cell wall which serves as the first defensive barrier against aphid feeding, the biosynthesis of lignin is catalyzed by a series enzymes and regulatory transcription factors. We previously found that the new phytohormone, strigolactone (SL), inhibits the synthesis of lignin, while enhances the aphid feeding in chrysanthemum, however, how SL regulates the biosynthesis of chrysanthemum lignin, thereby regulating the resistance of chrysanthemum to aphid, remains unknown. Therefore, in the present proposal, we aim to isolate genes involved in the lignin biosynthesis by quantitative RT-PCR, RT-PCR and RACE cloning; to isolate transcription factors via yeast one-hybrid, and affinity trapping of DNA-binding proteins; and to identify gene function via overexpressing or artificial microRNA interfering transformation. The resistance of transgenic plants to aphid will be identified as well. Lignin content, lignin monolignols and the cell wall thickness will be detected via Phloroglucinol staining, UV autofluorescence, Nuclear magnetic resonance (NMR) and transmission electron microscope. Present study will illustrate the molecular regulatory network of lignin biosynthesis by strigolactone and how it regulates the chrysanthemum resistance to aphid. The findings will provide a guide for aphid control and minimize the application of chemicals in controlling aphid, thus the proposal is of important theoretical significance and practical value.