大蒜素抑制麦蛾产卵的生殖调控机制研究

The Angoumois grain moth, Sitotroga cerealella (Olivier), is the most serious stored grain pest in China. It is very difficult to control the pest with traditional control, due to two important factors that contribute to the pest status of the moth include its ability to develop resistance to insecticides and the tendency of larvae to feed inside grains. It becomes the important new method to control the moth by manipulating adults’ oviposition with botanical pesticide. Our previous research shows that allicin possesses the characterics to disturb the two sexes’ mating and inhibit female’s oviposition at a certain dose; however, allicin still inhibits female’s oviposition at a lower dose that has no effect on the mating behavior; transcriptional sequencing results showed that allicin can significantly change the expression level of 100 more genes related with insect reproduction. Further research indicated that the formation of egg and egg shell from a mated female was delayed, and the vitellin contents and the expression level of vitellogenin gene (Vg) in the ovaries were inhibited; moreover, the whole protein content secreted by male accessory gland was also decreased.We speculate that allicin may affect the function of these proteins secreted by male accessory gland and then disturb the female’s postmating effect, but the actual mechanism is not clear now.Therefore, based on the results, the work will be performed to study the post-maing female’s physiology and behavior for clarification the control effect of allicin to the moth reproduction; meanwhile, the function of important genes involved in reproductive would be discussed and verified from male accessory gland by some molecular biological technologies. The results of the study will lay a foundation for further understanding the molecular mechanism of garlic on the regulation of the reproductive performance, and provide technical support for the green storage of grain.

麦蛾是重要储粮害虫，具有幼虫在粮粒内为害的特点，常规防治方法难以奏效，且抗药性问题严重，利用植物源杀虫剂控制麦蛾成虫产卵是潜在的替代防控措施。大蒜素可干扰麦蛾两性交配并抑制产卵，我们发现不影响两性交配的低大蒜素剂量仍可抑制其产卵，转录组测序结果表明大蒜素显著影响了100多个生殖相关基因的表达。进一步研究发现麦蛾两性交配后卵子及卵壳发生受阻，卵黄原蛋白基因表达下降、卵巢卵黄原蛋白和雄性附腺分泌蛋白总含量降低。推测大蒜素通过干扰雄性附腺分泌蛋白的功能影响麦蛾的交配后效应，但作用机理尚未明确。基于此，本项目拟以内分泌系统调控的雄性附腺分泌蛋白为立足点，从麦蛾交配后效应方面阐明大蒜素对其生殖力的调控，并探讨关键内分泌激素及雄性附腺分泌蛋白中重要生殖相关基因的功能，最终明确大蒜素调控麦蛾生殖的作用靶标。研究结果将为深入阐明大蒜素调控麦蛾生殖的分子机理奠定基础，为粮食的绿色储存提供技术支撑。

本项目以内分泌系统调控的雄性附腺分泌蛋白为立足点，从麦蛾交配后效应阐明了大蒜素对其生殖力的调控，并探讨了关键内分泌激素及雄性附腺分泌蛋白中重要生殖相关基因的功能，明确了大蒜素调控麦蛾生殖的作用靶标。主要取得以下结果：.1.确定了大蒜素不影响麦蛾雄虫的交配行为但能抑制与之交配雌虫产卵的熏蒸浓度为0.010μL/L。明确了大蒜素干扰了雌雄虫的交配后行为，并扰乱了熏蒸后雄虫的代谢 速度，使得能量物质大大降低；.2. 阐明了DAT 显著降低了精包的大小、有效精包率、精包中的精子束与精子的数量以及精子活力，且双射精管中的精子长度显著长于精包中的精子。同时， DAT 处理 后精包中的无核和有核精子数量在任何时间段均显著少于CK 组；.3. 明确了DAT可通过影响雄虫保幼激素和蜕皮激素的合成、代谢基因的表达，使得相应的激素水平发生紊乱，从而影响了雄性生殖能力的改变；进一步转录组结果和生 化指标表明脂代谢通路上两种基因TGL 和HSL对雄虫生殖能力扮演着重要的角色，DAT可加速脂代谢过程，脂肪体中的脂滴明显比对照组空瘪，三酰甘油含量也显著下降；.4. 阐明了DAT 可作为一种有效的蛋白酶体抑制剂并抑制胰蛋白酶和类胰凝乳蛋白酶活性，导致蛋白质降解紊乱以及聚集体形成，最终抑制精子的形成。. 总之，DAT 通过加速雄虫脂代谢速率，从而降低麦蛾雄虫精子的质量，影响雄虫在交配过程中输送到雌虫体内的交配内容物；作为一种有效的蛋白酶体抑制剂，抑制精子的形成及活性，从而最终抑制了与之交配的雌虫产卵量。研究结果将为深入阐明大蒜素调控麦蛾生殖的分子机理奠定基础。