Krüppel homologue 1 调控大猿叶虫生殖可塑性的分子机制

Reproductive plasticity, the result of the long-term evolution, is an environmental adaption strategy, and considered as one of the most important reasons for insect pest outbreak. Many insects can perceive the information of seasonal environmental changes, such as photoperiod, to enter reproduction or diapause. This developmental switch represents a typical reproductive plasticity in insects. Previous studies have shown that juvenile hormone (JH) is the upstream regulatory signaling of reproductive plasticity, so investigating the downstream signaling of JH is the key step for uncovering the molecular mechanisms of reproductive plasticity. In this project, we plan to use the cabbage beetle Colaphellus bowringi, which has facultative diapause, as the experimental animals to study the mechanism of JH-regulated reproductive plasticity by focusing on the transcriptional factor Kr-h1 (the early key gene of JH signaling). Briefly, we will analyze the functions of Kr-h1 in reproductive plasticity, establish the signal pathways of Kr-h1-regulated reproductive plasticity, and reveal the transcriptional mechanisms of the genes directly regulated by Kr-h1 using various methods, such as RNA-seq, RT-qPCR, RNAi, yeast two-hybrid system, Co-IP, and EMSA. Our results will not only reveal the molecular mechanisms of insect reproductive plasticity regulated by JH, but also deepen the understanding of insect seasonal adaptation mechanism and provide theoretical basis for the development of pest management strategies based on insect reproductive plasticity control.

生殖可塑性是昆虫长期进化形成的一种环境适应策略，是造成农业害虫猖獗爆发的关键因素之一。多种昆虫可感受光周期等季节性环境变化，从而进入生殖或滞育，这是昆虫生殖可塑性的范例。保幼激素JH是诱导昆虫生殖可塑性的上游信号，解析其所引发的下游信号途径是阐明昆虫生殖可塑性分子机制的关键。因此，本项目以具有兼性滞育特性的蔬菜害虫大猿叶虫为材料，以JH下游早期的关键转录因子Krüppel homologue 1 (Kr-h1)为切入点，利用比较转录组、定量PCR、RNAi、酵母双杂交、Co-IP、启动子活性分析和EMSA等技术和方法，明确Kr-h1对生殖可塑性的调节作用，建立Kr-h1调控生殖可塑性的信号途径，阐明Kr-h1对生殖可塑性相关基因的转录调控机制。研究结果不仅能解析昆虫生殖可塑性JH调控的分子机制，深化人们对昆虫季节性适应机制的认识，也可为发展基于生殖可塑性调控的害虫绿色防控策略奠定理论基础。

很多昆虫可以响应季节性环境变化而进入生殖或滞育，表现出明显的生殖可塑性。这种生殖可塑可以帮助害虫规避不良环境、维持种群，这是害虫猖獗爆发的一个重要原因。保幼激素JH是决定昆虫生殖可塑的关键内分泌因子，但是JH下游信号如何调节生殖可塑还不得而知。已知转录因子Kr-h1是JH信号的一个初级响应基因，分析其在生殖可塑中的功能和作用机制，将有助于阐明JH调节昆虫生殖可塑的深层机制。因此，本项目以蔬菜害虫大猿叶虫为材料，结合RNA-seq，定量PCR、RNAi、生理生化分析等技术和方法，旨在明确Kr-h1对生殖可塑性的调节作用，建立Kr-h1调控生殖可塑性的信号途径，阐明Kr-h1对生殖可塑性相关基因的转录调控机制。通过项目研究，我们取得如下重要结果和关键数据：1）Kr-h1通过调控大量基因表达促进生殖发育、抑制滞育准备；2）Kr-h1通过上调DNA复制基因表达促进生殖发育，通过上调甘油三脂水解酶表达从而降低脂肪储存进而抑制滞育；3）Kr-h1通过超级转录延伸复合体SEC调节基因转录进而控制生殖可塑。这些结果不仅解析了JH调节生殖可塑的分子机制，还能为基于生殖可塑性调控的害虫绿色防控策略奠定理论基础。