红火蚁蚁后信息素调控工蚁DNA甲基化影响社会分工的机制

Queen pheromone plays a quite critical role in regulating worker growth and division of labor in social insects. The difference of gene expression among behaviorally different worker castes is largely results from alteration of epigenetic modifications such as DNA methylation. Exploring the epigenetic mechanism of DNA methylation has important theoretical and practical significance for understanding the genetic and evolution of social insect, as well as for the beneficial insect utilization and pest control. Thus, this project will use the fire ants Solenopsis invicta as research material. The queen-right (QR) and queen-less (QL) nests will be regarded as the queen pheromone treatment and control groups, respectively. Firstly, the social behavior and hormone titers of nurse and forager workers will be compared between QR and QL nests with behavioral observation and liquid chromatography methods. Secondly, using the whole genome DNA methylation sequencing and transcription sequencing methods, the differentially methylated regions and differentially expressed genes will be compared between nurses and foragers in QR and QL nests, inwhich the genes involved in behavioral regulation of workers will be picked out from the significantly enriched pathways. Finally, we use RNAi method to suppress the expression of selected important genes of workers in QR nest to validate their function in regulating social behavior and physiological state of workers. Expected results will reveal the DNA methylation mechanism of queen pheromone regulating and maintaining workers division of labor.

王虫信息素对社会性昆虫工虫的生长发育和社会分工具有重要的调节作用，而不同分工的工虫间基因表达的差异很大程度上是由于DNA甲基化等表观遗传修饰变化引起的，探究王虫信息素对工虫社会分工过程中大脑DNA甲基化的调节机制，对于了解社会性昆虫的遗传与生物进化、益虫利用与害虫防治等方面均具有重要的理论与实际意义。本项目以红火蚁作为研究对象，将巢中有蚁后和无蚁后分别作为蚁后信息素处理组和对照组。首先，利用行为记录和液相色谱法比较不同处理组工蚁（哺育蚁/觅食蚁）的行为与激素含量差异。其次，利用全基因组DNA甲基化和转录组测序方法，比较不同处理组间工蚁的基因表达和甲基化差异，并从与工蚁行为调控相关的富集通路里面筛选出关键基因。最后，采用RNAi方法抑制关键基因在工蚁体内的表达，验证基因在调控工蚁社会行为及生理状态方面的功能。预期研究结果将揭示DNA甲基化在蚁后信息素调控工蚁社会分工过程中的作用机制。

蚁后信息素对红火蚁工蚁的生长发育和社会行为具有重要的调节作用，而不同行为分工在一定程度上是由于甲基化等表观遗传修饰引起的。本项目研究了在有蚁后和无蚁后两种条件下，工蚁的行为、生理、基因表达、RNA甲基化等方面的差异，发现蚁后信息素对工蚁的行为、生理及基因表达和RNA甲基化等多个方面具有重要的调节作用。通过RNAi干扰重要基因的表达，结果表明蚁后信息素对工蚁的调节作用可能是通过RNA甲基化等表观遗传调控基因表达，从而引起行为的变化。本研究结果揭示了RNA甲基化等表观遗传机制在蚁后信息素调控工蚁社会分工过程中具有重要的作用，为将来基于行为的红火蚁的防治策略提供参考依据。