Jiang Tao, Chen Yanhua, Tan Zhichen, Li Jiashuang, Qian Ping, Tang Shunming, Shen Xingjia
Jiangsu Key Laboratory of Sericutural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, China.
Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, Jiangsu, China.
Dev Growth Differ. 2019 Feb;61(2):150-157. doi: 10.1111/dgd.12589. Epub 2019 Jan 17.
Diapause is an important characteristic of insects used to adapt to extreme changes in environmental conditions. Embryonic diapause of the bivoltine silkworm (Bombyx mori) is determined by environmental conditions experienced by the mother while in the embryo stage. If they are incubated at 25°C with natural light, their progenies will be diapause-destined. If they are incubated at 17°C in darkness, their progenies will be non-diapause-destined. The molecular mechanism of diapause remains unknown. In the present study, we analyzed two downregulated genes (BGIBMGA003835, BGIBMGA012335) and two upregulated genes (BGIBMG012996, BGIBMG002426) related to carbohydrate metabolism, verified differentially expressed in ovaries and heads of 1-day-old fifth-instar larvae to 6-day pupae by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). In line with published data, the expression level of these genes in larvae were generally lower than in pupae. We further analyzed the expression levels of the four genes in BmN cells that had been treated with various concentrations of diapause hormone (DH). It demonstrated that the expression of these genes was affected by DH. Knockdown of the selected genes in non-diapause-destined female pupae changed the fate of the progeny from non-diapause- to daipause-destined, as seen by the appearance of diapause eggs. Our study provides insight into the molecular mechanism of diapause in B. mori.
滞育是昆虫用于适应环境条件极端变化的一个重要特征。二化性家蚕（Bombyx mori）的胚胎滞育由母体在胚胎阶段所经历的环境条件决定。如果它们在25°C自然光照下孵化，其后代将注定进入滞育。如果它们在17°C黑暗环境中孵化，其后代将注定不进入滞育。滞育的分子机制仍然未知。在本研究中，我们分析了两个与碳水化合物代谢相关的下调基因（BGIBMGA003835、BGIBMGA012335）和两个上调基因（BGIBMG012996、BGIBMG002426），通过定量实时逆转录聚合酶链反应（qRT-PCR）验证了它们在1日龄五龄幼虫至6日龄蛹的卵巢和头部中差异表达。与已发表的数据一致，这些基因在幼虫中的表达水平通常低于蛹中的表达水平。我们进一步分析了用不同浓度滞育激素（DH）处理的BmN细胞中这四个基因的表达水平。结果表明这些基因的表达受DH影响。在注定不进入滞育的雌性蛹中敲低选定基因会改变后代的命运，从不进入滞育变为进入滞育，这从滞育卵的出现可以看出。我们的研究为家蚕滞育的分子机制提供了见解。
