Gene expression profiling of diapause termination in E and Z strains of the European corn borer moth, Ostrinia nubilalis

Evolutionary change in diapause timing will be key for insects to adapt to a globally warming climate. However, the molecular mechanisms behind shifts in diapause timing are still unclear. The European corn borer moth (Ostrinia nubilalis) shows evolved differences in the length of larval diapause termination, where Z-strain individuals have a long termination time and E-strain individuals have a short termination time. Here, we use whole transcriptome profiling of larval head tissues through a developmental time-course of diapause termination to, i) identify putative loci responsible for initiating divergence in diapause timing, and ii) identify downstream molecular pathways that may direct moths to an earlier or later end of diapause. As diapause is induced under short-day conditions (12:12 light:dark) and broken under long-day conditions (16:8 light:dark), we sample both strains under short-day conditions during diapause maintenance, and on days 1 and 7 after exposure to long-day conditions during diapause termination, to illuminate the critical mechanisms for observed shifts to seasonal timing.

昆虫在适应全球变暖的气候过程中，其滞育期时间的进化变化将起到关键作用。然而，滞育期时间变化背后的分子机制尚不明确。欧洲玉米螟（Ostrinia nubilalis）在幼虫滞育期终止的时间长度上表现出进化差异，其中Z株个体具有较长的终止时间，而E株个体则具有较短的终止时间。本研究通过在滞育期终止的发育时间进程中，对幼虫头部组织进行全转录组分析，旨在i) 确定导致滞育期时间分化起始的潜在位点，以及ii) 确定可能引导蛾类提前或推迟滞育期结束的下游分子通路。由于滞育期在短日照条件下（12:12 光暗）诱导，而在长日照条件下（16:8 光暗）打破，我们在滞育期维持期间以及暴露于长日照条件后第1天和第7天，对两种株系进行采样，以阐明观察到的季节性时间变化背后的关键机制。