昆虫与植物相互作用过程中，许多信号分子在其间传递和作用。sRNA作为机体间传递的重要信号分子，参与调控植物和动物的防御反应。项目前期研究发现棉铃虫取食dcl1突变体拟南芥后体重显著降低，总脂肪含量降低，脂滴量减少，脂代谢相关基因表达明显变化；sRNA高通量测序和定量验证发现去除消化道棉铃虫中出现拟南芥sRNA，且与脂代谢酶基因有潜在结合。在此基础上项目拟开展如下研究：1）采用体外荧光素酶、RNA免疫共沉淀和共定位实验，确定拟南芥sRNA对棉铃虫脂代谢酶的调控作用；2）昆虫过表达或沉默植物sRNA，分析其对总脂肪含量及脂代谢基因和蛋白表达的影响；3）植物过表达/沉默sRNA以及昆虫RNAi/rescue实验，阐明植物sRNA对昆虫脂代谢的调控机制。研究结果不仅将发现昆虫与植物互作中防御机制的调控节点，还将揭示植物sRNA跨界调控昆虫脂代谢的作用机制，对指导抗虫育种和害虫有效治理具有重要意义。

Many signaling molecules that transmitted among insects and plants regulate the interaction of insects and plants. Small RNA (sRNA) is one of these signaling molecules. Our preliminary dates showed that dcl1 mutation significantly reduces the growth of cotton bollworm feeds on plants. The expressions of lipid metabolism genes are also significantly changed in bollworms fed with dcl1 mutant plants compared with bollworms fed with CK plants. Moreover, the fat content and the lipid droplet content of bollworms feed with dcl1 mutant plants are much lower than those of bollworms feed with CK plants. We then removed the bollworm guts and found plant sRNAs accumulate in the rest organs of bollworm. These sRNAs potentially target bollworm genes and regulate their expressions. These results suggested that these plant sRNAs can regulate the lipid metabolism of insects.. Next, we will determine the regulation of lipid metabolic enzyme by plant sRNAs in insects with in vitro luciferase, RNA co-immunoprecipitation and co-localization assays. The function of these sRNAs in bollworms will be validated by directly injecting the agomir/antagomir into bollworms. The cross-kingdom regulations of these plant sRNAs in insects will also be determined in sRNA over-expression and knockout plants. This proposed study not only will reveal the biological functions of cross-kingdom sRNAs, but also will identify key genes involved in pest-plant interaction. The overall goal of this proposal is developing novel technology to control the pests and benefit crop production.