The limited regulatory roles of juvenile hormone degradation pathways in reproductive diapause preparation of the cabbage beetle, Colaphellus bowringi
The limited regulatory roles of juvenile hormone degradation pathways in reproductive diapause preparation of the cabbage beetle, Colaphellus bowringi
复制标题
保幼激素降解途径在卷心菜甲虫（Colaphellus Bowringi）生殖滞育准备中的有限调节作用。
DOI：
10.1016/j.jinsphys.2019.103967
复制
发表时间：
2019-11-01
影响因子：
2.2
通讯作者：
Wang, Xiao-Ping
中科院分区：
文献类型：
--
作者：
Guo, Shuang;Sun, Dan;Wang, Xiao-Ping
保幼激素（JH）的缺乏会导致许多昆虫出现生殖滞育。 JH生物合成下调被认为是降低JH水平的关键因素。然而，上调的 JH 降解是否也会导致 JH 缺乏，进而导致生殖滞育仍然知之甚少。在这项工作中，我们使用卷心菜甲虫（Colaphellus Bowringi）作为模型，通过 RNAi 介导的功能丧失研究了 JH 降解基因在生殖滞育准备中的功能。克隆了三个 JH 降解基因，包括 JH 环氧化物水解酶 1 (JHEH1)、JHEH2 和 JH dial 激酶 (JHDK)，推导的蛋白质包含在其他昆虫的相同蛋白质中明确识别的保守结构域和基序。与非滞育 (NDD) 雌性相比，JHEH1、JHEH2 和 JHDK 在滞育 (DD) 雌性中均高度表达。敲除 DD 雌性中的这些 JH 降解基因会升高 JH 信号传导，这通过 JH 诱导基因和卵黄蛋白原基因表达的增加表明，但不会诱导卵巢发育。同时，JH降解基因的敲低显着抑制了滞育相关的表型性状，包括脂肪储存以及与脂肪储存和应激耐受相关的基因的表达。光周期转移实验表明，DD雌性中JHEH2的高表达是由幼虫阶段的长日照预先编程的。通过 Methoprene 耐受性和 Kriippel 同源物 1 敲除 JH 信号传导可诱导 DD 雌性中 JHEH2 的高表达。考虑到JH降解基因的RNAi影响了DD雌性中的一些滞育相关性状，但未能完全诱导非滞育表型，我们得出结论，JH降解途径在C. Bowringi的生殖滞育准备中发挥有限的调节作用。
The absence of juvenile hormone (JH) induces reproductive diapause in many insects. Downregulated JH biosynthesis is considered the critical factor that decreases the JH level. However, whether upregulated JH degradation could also contribute to JH deficiency and then induce reproductive diapause remains poorly known. In this work, we used the cabbage beetle, Colaphellus bowringi, as the model and investigated the function of JH degradation genes in reproductive diapause preparation via RNAi-mediated loss-of-function. Three JH degradation genes, including JH epoxide hydrolase 1 (JHEH1), JHEH2, and JH dial kinase (JHDK), were cloned, and the deduced proteins contained the conserved domains and motifs well-identified in the same proteins of other insects. JHEH1, JHEH2, and JHDK were all highly expressed in the diapause-destined (DD) females compared to the non-diapause-destined (NDD) females. Knocking down these JH degradation genes in DD females elevated JH signaling, indicated by increased expressions of JH-inducible genes and vitellogenin genes, but did not induce ovary development. Meanwhile, the knockdown of JH degradation genes significantly suppressed diapause-associated phenotypic traits, including fat storage, and the expression of genes related to fat storage and stress tolerance. A photoperiodic transfer experiment suggested that high expression of JHEH2 in DD female was preprogrammed by long day during the larval stage. Knockdown of JH signaling through Methoprene-tolerant and Kriippel homolog 1 induced high expression of JHEH2 in DD females. Considering that RNAi of JH degradation genes affected some diapause-related traits in DD females but failed to induce the non-diapause phenotype in full, we conclude that JH degradation pathways play limited regulatory roles in the reproductive diapause preparation of C. bowringi.