Niu Zhi-Long, Wei Jian, Wang Qian, Yang Yu-Bo, Gao Ying-Nan, Li Lu, Jia Jia, Guo Wei, Zhao Dan
College of Plant Protection, Hebei Agricultural University, Baoding, China.
Experiment and Practice Training Center, Hebei Agricultural University, Baoding, China.
J Insect Physiol. 2025 Jul 21;165:104861. doi: 10.1016/j.jinsphys.2025.104861.
Nuclear receptors (NRs) are ligand-regulated transcription factors that play crucial roles in insect growth and development. However, their functions in Holotrichia oblita Faldermann remain uncharacterized. In this study, we identified and characterized three HoNRs from H. oblita. Spatiotemporal expression analysis revealed that all three HoNRs were predominantly expressed in eggs and first-instar larvae. Tissue localization showed high expression in the epidermis, fat body, and rectum. RNA interference (RNAi) experiments demonstrated that silencing these HoNRs reduced larval feeding, impaired molting, and resulted in a 37-50 % weight inhibition rate and a 73-93 % mortality rate. Hematoxylin-eosin staining showed that knockdown of HoHR3, HoE75, and HoEcR led to the formation of a thinner cuticle compared to controls, accompanied by a 46-48 % reduction in chitin content and downregulation of chitin metabolic Pathway genes. Additionally, the expression of these HoNRs was influenced by 20E at different time points. Therefore, these findings demonstrate that these three HoNRs are essential for normal molting in H. oblita through chitin metabolic pathway regulation.
核受体（NRs）是配体调节的转录因子，在昆虫生长和发育中起关键作用。然而，它们在暗黑鳃金龟中的功能仍未得到表征。在本研究中，我们从暗黑鳃金龟中鉴定并表征了三种HoNRs。时空表达分析表明，所有三种HoNRs主要在卵和一龄幼虫中表达。组织定位显示在表皮、脂肪体和直肠中高表达。RNA干扰（RNAi）实验表明，沉默这些HoNRs会减少幼虫取食、损害蜕皮，并导致体重抑制率为37-50%，死亡率为73-93%。苏木精-伊红染色显示，与对照组相比，敲低HoHR3、HoE75和HoEcR会导致表皮变薄，同时几丁质含量降低46-48%，几丁质代谢途径基因下调。此外，这些HoNRs的表达在不同时间点受20E影响。因此，这些发现表明这三种HoNRs通过几丁质代谢途径调节对暗黑鳃金龟的正常蜕皮至关重要。
