高温和湿度互作胁迫下韭菜迟眼蕈蚊表型可塑性响应及其机制

The damage of Bradysia odoriphaga, is one of the tremendous biological disasters, hampers the production of Chinese chives in China. Our previous data has shown that the interaction between the high temperature and humidity in summer has effects on phenotypic plasticity of Bradysia odoriphaga, which thus significantly affects population quantity. Based on our preliminary data, this research will be focused on the effects of different temperature and humidity on the development, growth and reproduction of Bradysia odoriphaga, to unravel how their life history in response to climate changes including temperature and humidity in summer. Furthermore, we will address the cross-stress between high temperature and humidity on the modulation of the energy allocation and metabolism for their larvae, and reveal the physiological adaptation strategies of the population growth and development to the temperature and humidity variation. To the end, heat shock proteins (HSPs) and aquaporins (APQs) family genes under the same stress condition will be detected. RNA interference (RNAi) as a gene knockdown technique will be carried out to clarify the molecular strategies of Bradysia odoriphaga to survive summer. The results of this study will elucidate the stress response and mechanism of Bradysia odoriphaga to high temperature and humidity variation in summer, which will contribute to the theoretical and practical significance for pest forecasting and green control.

韭菜迟眼蕈蚊危害是制约我国韭菜生产的重大生物灾害。申请者前期研究发现夏季高温和湿度互作影响韭菜迟眼蕈蚊的表型可塑性，从而显著影响其田间种群的数量。本项目拟在此基础上，研究不同高温和湿度互作对韭菜迟眼蕈蚊胚胎发育、生长和繁殖的影响，明确其生活史对夏季温湿度气候变化的响应特性；并进一步研究高温和湿度互作胁迫对韭菜迟眼蕈蚊幼虫体内能量分配和新陈代谢的调节，揭示其种群生长发育对温湿度变化的生理适应策略；最后研究温湿度胁迫条件下与热耐受性密切相关的热休克蛋白(HSPs)和协助水分运输的水通道蛋白(APQs)家族基因的表达特性，并借助RNAi技术对相关基因实现沉默后的分析，阐明韭菜迟眼蕈蚊越夏的分子对策。研究结果将阐明越夏昆虫对夏季高温和湿度气候变化的响应方式及响应机制，对害虫测报和绿色防控具有重要的理论与实践意义。

韭菜迟眼蕈蚊Bradysia odoriphaga（俗称：韭蛆）是我国蔬菜产业的重大生物灾害。本项目利用生物生态学、分子生物学等手段，从宏观和微观层面研究高温和湿度互作胁迫下韭菜迟眼蕈蚊表型可塑性响应及其机制，结果表明：韭菜迟眼蕈蚊种群数量与月平均大气温度和土壤温度显著相关，尤其是7-8月的夏季高温是制约其田间种群数量的关键因子。韭菜迟眼蕈蚊能够正常生存的湿度范围较广，其种群数量与月平均大气相对湿度和土壤含水量无显著相关性，但同等条件下，土壤含水量高的田块韭菜迟眼蕈蚊数量相对较多。随着温度升高和时间延长，韭菜迟眼蕈蚊的死亡率增加。37℃胁迫4 h是韭菜迟眼蕈蚊幼虫开始死亡的临界值，同样也会显著抑制其蛹的羽化。无论高温胁迫处理幼虫还是蛹，只要后续能羽化出成虫，对雌性成虫的寿命无显著影响，但显著缩短了雄性成虫的寿命。高温胁迫幼虫，不影响其后续成虫的产卵量和卵孵化，但是胁迫蛹能够降低其后续成虫的产卵量和卵孵化率。从生殖器形态结构上观察，高温胁迫对雄性的影响显著大于雌性。通过第三代全长转录组测序获得韭菜迟眼蕈蚊雌雄成虫的差异基因，克隆并验证高温胁迫能够显著抑制雌性卵黄原蛋白基因BrcVg1和BrcVg2的表达。同时，通过比较高温胁迫组与对照组韭菜迟眼蕈蚊的转录组数据差异，发现它们之间存在654个表达差异基因，并找到韭菜迟眼蕈蚊与搜寻寄主相关的28个OBP基因，3个CSP基因和46个OR基因，重点对差异基因中的热休克蛋白基因进行研究，发现高温胁迫诱导3个sHsp家族的基因显著上调。在揭示高温胁迫明确韭菜迟眼蕈蚊响应机制的基础上，本项目还发明和完善了防治韭菜迟眼蕈蚊的覆膜升温法，同时还研发出“温水滴灌”系统模型，筛选出高效的绿色防控方法。本项目构建了“从哪里来到哪里去”的闭路研究思路，既揭示了高温和湿度互作胁迫下韭菜迟眼蕈蚊表型可塑性的响应及其机制，也利用寄主与害虫耐受温度的差异研发了防控技术，开辟了害虫绿色防控新方向，为其它作物害虫的新型绿色防控技术研发奠定了基础。