跨界RNA沉默信息流的抗虫作用机制及功能

RNA silencing is a universal gene regulatory mechanism mediated by small RNA (sRNA) in eukaryotic organisms. One of the major functions is to inhibit the invasion of genetic materials from other organisms, which contributes to the resistance against a variety of biotic and abiotic stresses. The cross-kingdom RNA silencing has been proved to be transmitted from crops to insects and implicated in the anti-insect defence to Helicoverpa armigera, cotton bollworm, and aphid, which both are important crop pests in China. However, the generation, transportation, and function of the cross-kingdom RNA silencing are largely unknown. The piercing-sucking mouthpart of the aphid could bi-directionally transport molecules involved in the interaction between plants and insects. Focusing on aphids and cotton ballworm, we propose to identify the signal carriers of the cross-kingdom plant-to-insect silencing, uncover the mechanism of plant-to-insect silencing, and explore the possibility and function of insect-to-plant silencing. Taken together, this proposed study will not only reveal the biological function of cross-kingdom RNA silencing, but also benefit our knowledge base of the interaction between crop and insect. It will also provide new insights into the development of next generation anti-pest technology, which is much safer and more powerful and will significantly benefit the sustainable development of agriculture

中文摘要：RNA沉默是一种普遍存在于真核生物内，通过小分子RNA调节基因表达的调控方式。其主要功能之一是抵御外源遗传物质的入侵，帮助机体更好的应对各种胁迫。跨界RNA沉默已经被证明可以由作物传播到昆虫，并参与作物对棉花主要害虫--棉铃虫和影响农业生产的重要害虫--蚜虫等的抵抗，这为抗虫研究提供了新的研究思路。但是跨界RNA沉默的发生、传播及分子机制却研究甚少。蚜虫的刺吸式口器可以在昆虫和作物之间双向传递物质。因此，本项目选择蚜虫和玉米为研究模型，全面解析植物到昆虫传播的抗虫RNA沉默信息流组份；揭示植物跨界信息流在昆虫内的作用机制；明确昆虫到植物RNA沉默发生的可能性及作用,从不同角度阐明跨界RNA沉默在植物昆虫互作过程中的生物学意义。本研究的开展将有助于拓宽对作物昆虫相互作用的认识，为开发更加安全专一的新一代抗虫技术提供新的思路，对农作物生产和可持续发展具有重要的社会经济效益。

RNA沉默是一种普遍存在于真核生物体内，通过小分子RNA调节基因表达的调控机制。RNA沉默的主要功能之一是帮助机体更好的应对各种胁迫。有研究表明植物可向昆虫传递体内表达的异源RNA，从而起到抗虫的作用，而内源RNA沉默是否参与抗虫信息流以及昆虫向植物的跨界RNA沉默仍知之甚少。本项目研究发现棉铃虫取食后植物sRNA的积累和不同长度sRNA的分布均发生显著变化；AGO1和RBP2为植物RNA沉默途径中的关键基因，植物AGO1的功能缺失或RBP2过量表达会造成取食昆虫体重大幅降低；进一步研究发现昆虫体重下降是由于取食这些植物后，体内脂代谢基因的累积发生显著变化，进而影响到脂肪的累积；蚜虫取食过程中，可将大量RNA，包括miRNA，向植物传递，说明昆虫向植物跨界RNA沉默机制的存在。本研究对RNA沉默在植物昆虫互作过程中的作用和机制进行了比较系统的研究，阐释了RNA沉默在植物和昆虫的互作中的重要意义。