Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212100, Jiangsu, China; Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212100, Jiangsu, China.
Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212100, Jiangsu, China; Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212100, Jiangsu, China.
Gene. 2023 Sep 25;881:147626. doi: 10.1016/j.gene.2023.147626. Epub 2023 Jul 8.
Diapause of the silkworm (Bombyx mori) is an important ecological adaptation strategy regulated by multiple signaling pathways. As an evolutionarily conserved signaling pathway, the insulin/IGF signaling (IIS) pathway is essential in regulating lifespan, energy accumulation, and stress resistance in diapause insects. However, the regulatory mechanism of IIS on diapause in B. mori is still not fully understood. To investigate the role of the IIS pathway in regulating diapause, we first analyzed the transcription levels of the insulin receptor (BmINR) and its downstream gene adenylate cyclase 6 (BmAC6). The diapause-terminated eggs of a bivoltine strain QiuFeng (V-QF) were incubated at 25 °C in natural room light for preparing diapause egg producers (DEPs) and at 17 °C in total darkness for preparing non-diapause egg producers (NDEPs), respectively. Then we investigated the effects of BmINR and BmAC6 on diapause phenotype and expression of diapause-related genes by RNA interference (RNAi) and overexpression techniques. The results showed that the mRNA expression levels of BmINR and BmAC6 in the head and ovary of NDEPs were higher than those in DEPs during the early and middle pupal stages. Furthermore, when BmINR was knocked down in the NDEPs, approximately 14.43% of eggs were in light red color and subsequently changed into gray-purple color after 48 h post-oviposition, then stayed in a diapause state. On the other hand, overexpression of BmINR or BmAC6 via recombinant baculoviruses did not cause any obvious phenotypic alterations in NDEPs, but it upregulated the expression of genes related to carbohydrate metabolism, which provides energy for embryonic growth and development. Therefore, it can be concluded that BmINR and BmAC6 genes regulate embryonic diapause in bivoltine B. mori.
家蚕滞育是一种重要的生态适应策略，受多种信号通路调控。作为一个进化上保守的信号通路，胰岛素/胰岛素样生长因子信号（IIS）通路在调控滞育昆虫的寿命、能量积累和抗逆性方面至关重要。然而，IIS 在家蚕滞育中的调控机制尚不完全清楚。为了研究 IIS 通路在调控家蚕滞育中的作用，我们首先分析了胰岛素受体（BmINR）及其下游基因腺苷酸环化酶 6（BmAC6）的转录水平。将二化性秋丰（V-QF）滞育终期卵在 25°C 的自然光照下孵化，以制备滞育卵生产者（DEPs）；在 17°C 的全暗环境下孵化，以制备非滞育卵生产者（NDEPs）。然后，我们通过 RNA 干扰（RNAi）和过表达技术，研究了 BmINR 和 BmAC6 对滞育表型和滞育相关基因表达的影响。结果表明，在早期和中期蛹期，NDEPs 头部和卵巢中 BmINR 和 BmAC6 的 mRNA 表达水平均高于 DEPs。此外，当 NDEPs 中的 BmINR 被敲低时，约 14.43%的卵呈浅红色，随后在产卵后 48 小时后变为灰紫色，然后处于滞育状态。另一方面，通过重组杆状病毒过表达 BmINR 或 BmAC6 不会引起 NDEPs 出现任何明显的表型改变，但它上调了与碳水化合物代谢相关基因的表达，为胚胎生长和发育提供能量。因此，可以得出结论，BmINR 和 BmAC6 基因调控二化性家蚕的胚胎滞育。
