Tra调控烟粉虱性别决定的分子机理研究

性别决定是发育和进化生物学研究的一个重大问题。昆虫性别决定级联的上游调控机制复杂多变，但下游机制相对保守，特别是tra+tra2→dsx的调控模式在大多数昆虫中存在共性。申请者在前期研究中，鉴定了烟粉虱tra、tra2及dsx基因，发现tra2与dsx存在级联互作，且二者与雄虫生殖器的形成有关。沉默tra，下游一系列性别决定基因的表达量均下调，推测tra是烟粉虱性别决定级联的主调控因子。为验证该假设，本项目拟开展以下研究：1）利用RT-PCR及RT-qPCR，分析tra及其它性别决定基因在胚胎发育早期的剪接及表达模式；2）利用特异性RNAi，明确tra在烟粉虱性别决定中的重要作用，以及tra与其它性别决定基因的关系，阐明烟粉虱性别决定级联调控的分子机理。研究结果不仅为解析其他单双倍体型昆虫的性别决定机制提供了理论指导，还为防治烟粉虱提供了潜在的分子靶标。

Sex determination is an outstanding question in developmental and evolutionary biology. The upstream regulatory mechanisms governing somatic sex determination cascade in insects are highly divergent, however the downstream regulatory mechanisms are relatively conserved. In particular, the tra + tra2 → dsx pathway is fairly common in most insects. In the proceeding phase of this proposed research, we identified tra, tra2 and dsx in the sweet potato whitefly, Bemisia tabaci, and found that dsx and tra2 interacted with each other and were important for male genitalia formation. More importantly, suppression of tra by dietary RNAi down-regulated an array of genes involved in sex determination cascade. Based on our preliminary research, we hypothesized that tra serves as a master regulator in B. tabaci sex determination cascade. To test this overarching hypothesis, we are planning the following studies: 1) RT-PCR and RT-qPCR were used to analyze the splicing and expression patterns of tra and other sex determination genes during early embryonic development; 2) specific RNAi were used to clarify the important role of tra in sex determination of B. tabaci and the relationship between tra and other sex determination genes, so as to further revealing the regulation mechanism of sex determination cascade in B. tabaci. A genetic understanding of tra and its regulatory gene networks in B. tabaci not only will shed light on the sex determination cascade in other haplodiploid insects, but also offer potential molecular targets to control this global invasive insect pest.