The KNRL nuclear receptor controls hydrolase-mediated vitellin breakdown during embryogenesis in the brown planthopper, Nilaparvata lugens
The KNRL nuclear receptor controls hydrolase-mediated vitellin breakdown during embryogenesis in the brown planthopper, Nilaparvata lugens
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KNRL核受体控制褐飞虱胚胎发生过程中水解酶介导的卵黄蛋白分解
DOI：
10.1111/1744-7917.12885
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发表时间：
2020-12-08
期刊：
影响因子：
4
通讯作者：
Sun, Zhong-Xiang
中科院分区：
文献类型：
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作者：
Lu, Kai;Cheng, Yi-Bei;Sun, Zhong-Xiang
卵磷蛋白（Vn）的稳态是卵生昆虫繁殖力的核心。大多数研究都集中在Vn的合成和运输上，作为卵黄发生期间卵子发育的组成部分;然而，人们对这种营养储备的利用如何影响胚胎发育知之甚少。在这里，我们表明，单一的直向同源物的knirps和knirps样核受体，KNRL，负调控Vn击穿抑制水解酶基因的表达，褐飞虱，褐飞虱。KNRL在成年雌性的卵巢中高度表达，通过RNA干扰敲低KNRL导致Vn分解加速和胚胎发育抑制。转录组测序分析表明，许多水解酶基因，包括组织蛋白酶和胰蛋白酶KNRL敲低后上调。9个显著富集的基因本体论术语中至少有8个是与蛋白水解相关的。KNRL基因敲除后，5个胰蛋白酶基因的表达水平和胰蛋白酶在胚胎中的酶活性显著增加。此外，胰蛋白酶注射延长卵的持续时间，延迟胚胎发育，加速Vn的分解，并严重降低卵的孵化率，类似于在KNRL沉默的N。lugens。这些观察结果表明，KNRL控制通过转录抑制水解酶在胚胎中的Vn分解。总的来说，这项研究为了解胚胎发育过程中胚胎营养储备是如何动员的提供了基础，并确定了几个基因和途径，这些基因和途径可能被证明是害虫防治的有价值的目标。
Vitellin (Vn) homeostasis is central to the fecundity of oviparous insects. Most studies have focused on the synthesis and transportation of Vn as a building block for developing eggs during vitellogenesis; however, less is known about how the utilization of this nutrient reserve affects embryonic development. Here, we show that the single ortholog of the knirps and knirps-like nuclear receptors, KNRL, negatively regulates Vn breakdown by suppressing the expression of hydrolase genes in the brown planthopper, Nilaparvata lugens. KNRL was highly expressed in the ovary of adult females, and knockdown of KNRL by RNA interference resulted in the acceleration of Vn breakdown and the inhibition of embryonic development. Transcriptome sequencing analysis revealed that numerous hydrolase genes, including cathepsins and trypsins were up-regulated after KNRL knockdown. At least eight of the nine significantly enriched Gene Ontology terms for the up-regulated genes were in proteolysis-related categories. The expression levels of five selected trypsin genes and the enzymatic activities of trypsin in the embryos were significantly increased after KNRL knockdown. Moreover, trypsin injection prolonged egg duration, delayed embryonic development, accelerated Vn breakdown and severely reduced egg hatchability, a pattern similar to that observed in KNRL-silenced N. lugens. These observations suggest that KNRL controls Vn breakdown in embryos via the transcriptional inhibition of hydrolases. Generally, this study provides a foundation for understanding how embryo nutrient reserves are mobilized during embryogenesis and identifies several genes and pathways that may prove valuable targets for pest control.