Wu Shuang, Tang Yan, Su Shaojun, Ding Wenbing, He Hualiang, Xue Jin, Gao Qiao, Qiu Lin, Li Youzhi
Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, College of Plant Protection, Hunan Agricultural University, Changsha, 410128, China.
Agricultural Bureau of Dingcheng County, Changde, 415006, China.
Mol Biol Rep. 2022 Dec;49(12):11765-11773. doi: 10.1007/s11033-022-07948-3. Epub 2022 Oct 6.
The nutritional signaling pathway regulates an insect's size, development, and lifespan, as well as playing a vital role in reproduction. The insulin/insulin-like growth factor signaling (IIS) pathway plays a key role in the nutrition signaling pathway. As an integral component of the IIS pathway, insulin receptor (InR), a receptor tyrosine kinase, plays a role in the insulin pathway by controlling reproduction in many insect species. However, the precise molecular function of InR in non-model insect reproduction is poorly understood.
In our study, Chilo suppressalis, a well-known rice pest, was used as a molecular system to determine the role of InR in insect reproduction. Sequencing the InR gene of C. suppressalis, comparing the amino acid sequence-specific structure, and constructing a phylogenetic tree revealed that this gene has four main domains: ligand binding L domain, Furin-like region, fibronectin type III domains, and Tyrosine kinase catalytic domain, which were all highly conserved in insects.
By characterizing the spatiotemporal expression profile of InR in different developmental stages and tissues, we found that InR gene expression was highest on the 3-day old in female pupae, 6th instar larvae, and fat body on the 6-day old in female pupae. InR gene expression may promote the molting and pupation of larvae and play a role in reproduction in the fat body. Furthermore, the RNA interference knockdown of InR dramatically reduced yolk deposition and blocked oocyte maturation. After suppression of InR, the expression of several other genes fluctuated to varying degrees.
In conclusion, InR is vital to reproduction and is expected to become a new target for pest management.
营养信号通路调节昆虫的体型、发育和寿命，并且在繁殖中起着至关重要的作用。胰岛素/胰岛素样生长因子信号传导（IIS）通路在营养信号通路中起关键作用。作为IIS通路的一个组成部分，胰岛素受体（InR）是一种受体酪氨酸激酶，在许多昆虫物种中通过控制繁殖在胰岛素通路中发挥作用。然而，InR在非模式昆虫繁殖中的精确分子功能尚不清楚。
在我们的研究中，使用一种著名的水稻害虫——二化螟作为分子系统来确定InR在昆虫繁殖中的作用。对二化螟的InR基因进行测序、比较氨基酸序列特异性结构并构建系统发育树，结果表明该基因有四个主要结构域：配体结合L结构域、弗林蛋白酶样区域、纤连蛋白III型结构域和酪氨酸激酶催化结构域，这些结构域在昆虫中都高度保守。
通过表征InR在不同发育阶段和组织中的时空表达谱，我们发现InR基因在3日龄雌蛹、6龄幼虫以及6日龄雌蛹的脂肪体中的表达最高。InR基因表达可能促进幼虫的蜕皮和化蛹，并在脂肪体的繁殖中发挥作用。此外，RNA干扰敲低InR显著减少了卵黄沉积并阻断了卵母细胞成熟。抑制InR后，其他几个基因的表达也有不同程度的波动。
总之，InR对繁殖至关重要，有望成为害虫防治的新靶点。
