Juvenile hormone regulates the photoperiodic plasticity of elytra coloration in a ladybird Harmonia axyridis

Many animals, including insects, exhibit plasticity of body color in response to environmental changes. Varied expression of carotenoids, major cuticle pigments, significantly contributes to body color flexibility. However, the molecular mechanisms by which environmental cues regulate carotenoid expression remain largely unknown. In this study, we used the ladybird Harmonia axyridis as a model to investigate the photoperiodic-responsive plasticity of elytra coloration and its endocrine regulation. It was found that H. axyridis females under long-day conditions develop elytra that are much redder than those under short-day conditions, resulting from the differential accumulation of carotenoids. Exogenous hormone application and RNAi-mediated gene knockdown indicate that carotenoid deposition was directed through the juvenile hormone (JH) receptor-mediated canonical pathway. Moreover, we characterized an SR-BI/CD36 (SCRB) gene SCRB10 as the carotenoid transporter responding to JH signalin..., ,

包括昆虫在内的诸多动物，均会响应环境变化而展现体色可塑性。类胡萝卜素作为主要的表皮色素，其表达差异是驱动体色可塑性的核心因素。然而，环境信号调控类胡萝卜素表达的分子机制目前仍未被完全阐明。本研究以异色瓢虫（Harmonia axyridis）为模式生物，探究其鞘翅（elytra）色泽的光周期响应可塑性及其内分泌调控机制。研究发现，相较于短日照条件，长日照环境下的异色瓢虫雌虫鞘翅颜色更为深红，该差异源于类胡萝卜素的积累量差异。通过外源激素处理与RNA干扰（RNAi）介导的基因敲低实验，本研究证实类胡萝卜素的沉积通过保幼激素（JH）受体介导的经典通路完成调控。此外，本研究还鉴定出一个隶属于SR-BI/CD36（SCRB）家族的基因SCRB10，其作为响应JH信号的类胡萝卜素转运蛋白……