利用二化螟内源microRNA培育抗二化螟转基因水稻的机理及应用研究

基于转基因植物表达针对害虫靶标基因的双链RNA（dsRNAs）或人工microRNAs（amiRNAs）诱导取食害虫的RNAi效应，已经成为一种重要的抗虫转基因作物培育策略。我们拟对一种新的利用RNAi培育抗二化螟水稻的方法进行研究。miRNA在昆虫的生长发育过程中扮演重要的调控角色。我们假设在水稻中超表达二化螟的miRNA，则取食该水稻的二化螟吸收水稻组织中过表达的二化螟miRNA后，体内miRNA水平异常上升，扰乱其调控功能，从而出现发育异常或致死。在前期工作中，20个二化螟miRNA序列被挑选和评价，其中5个miRNA在水稻中过表达后导致取食二化螟幼虫出现生长抑制、羽化异常、死亡率上升等RNAi表型。我们拟进一步对5个选择的miRNA开展靶标基因研究及生物学功能分析，双价amiRNA水稻培育及抗性评估，以及相应的田间抗性试验。

Transgenic plant-mediated RNAi has become a promising strategy of developing insect resistant crops, in which dsRNAs or artificial microRNAs (amiRNAs) aiming on pest target genes are overexpressed. In this project, a novel RNAi method of developing striped stemborer (SSB) resistant rice is studied. miRNAs play an important regulatory role in the growth and development of insects. It is hypothesized that the corresponding miRNA amount in SSB would rise abnormally when SSB feeds on transgenic rice overexpressing SSB endogenous miRNAs. Then the regulatory functions of miRNAs would be interfered, causing developmental abnormalities or mortality in SSB. In the previous study, 20 SSB miRNA sequences were selected and assessed, and among them 5 miRNAs caused obvious RNAi effects of the feeding SSB larvae when overexpressed in transgenic rice, including growth inhibition, abnormal eclosion, or higher mortality. The further research would be conducted including identifying the target genes of 5 selected miRNAs and studying their biological functions, developing dual amiRNA rice and evaluating their SSB resistance, and conducting SSB resistant evaluation under field conditions.