State Key Laboratory of Crop Stress Biology for Arid Areas and Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi 712100, China.
J Insect Physiol. 2020 Nov-Dec;127:104160. doi: 10.1016/j.jinsphys.2020.104160. Epub 2020 Oct 30.
Apolipoprotein D (ApoD) is a lipocalin superfamily member that plays important roles in the transport of small hydrophobic molecules, lipid metabolism, and stress resistance. Cuticular hydrocarbons are the principal components of the epicuticular lipid layer and play a critical role in water retention against environmental desiccation stress; however, the mechanism underlying the role of ApoD in insect desiccation tolerance has not yet been elucidated. Here, we report the molecular constitution, functional analysis, and phylogenetic relationship of the ApoD gene in Acyrthosiphon pisum (ApApoD). We found that ApApoD was transcribed throughout the life cycle of A. pisum, but was prominently expressed in the embryonic period and abdominal cuticle. In addition, we optimized the dose and silencing duration of RNAi, observing that RNAi against ApApoD significantly reduced the levels of both internal and cuticular hydrocarbons and adult fecundity. Moreover, cuticular hydrocarbon deficiency increased the sensitivity of aphids to desiccation stress and reduced their survival time, while desiccation stress significantly increased ApApoD expression. Together, it is confirmed that ApApoD participates in regulating cuticular hydrocarbon content of aphids under desiccation stress and is crucial for aphid reproduction. Therefore, the ApApoD gene of A. pisum may be a potential target for RNAi-based insect pest control due to its involvement in cuticular hydrocarbon accumulation and reproduction.
载脂蛋白 D（ApoD）是脂联素超家族的一员，在小分子疏水性分子的运输、脂质代谢和应激抗性中发挥重要作用。表皮烃是表皮脂质层的主要成分，在保持水分方面起着关键作用，以抵抗环境干燥胁迫；然而，ApoD 在昆虫耐旱性中的作用机制尚未阐明。在这里，我们报告了豌豆蚜（Acyrthosiphon pisum）（ApApoD）中 ApoD 基因的分子构成、功能分析和系统发育关系。我们发现 ApApoD 在豌豆蚜的整个生命周期中都有转录，但在胚胎期和腹部表皮中表达最为明显。此外，我们优化了 RNAi 的剂量和沉默时间，观察到针对 ApApoD 的 RNAi 显著降低了内部和表皮烃的水平以及成虫的繁殖力。此外，表皮烃缺乏增加了蚜虫对干燥胁迫的敏感性并降低了它们的存活时间，而干燥胁迫显著增加了 ApApoD 的表达。综上所述，证实了 ApApoD 参与调节干旱胁迫下蚜虫的表皮烃含量，对蚜虫的繁殖至关重要。因此，由于其参与表皮烃积累和繁殖，豌豆蚜的 ApApoD 基因可能成为基于 RNAi 的害虫防治的潜在靶标。
