The olfactory system of insects is crucial in modulating behaviors such as host seeking, mating, and oviposition. Odorant-binding proteins (OBPs) are involved in semiochemical recognition. OBPs recognize and bind odorants and transport them to odorant receptors located in olfactory neurons. Harmonia axyridis (Coleoptera: Coccinellidae) is a widely used predacious biological control agent for many agricultural and forestry pests. This study identified 19 OBPs in H. axyridis based on the antennal and whole-body transcriptomes of adults and obtained all the full-length open reading frames, including 11 ‘Classic’ OBPs, 7 ‘Minus-C’ OBPs and 1 ‘Plus-C’ OBP. They encoded 125 to 241 amino acid proteins with molecular weights ranging from 13.75 to 27.75 kDa and isoelectric points ranging from 4.15 to 8.80. Phylogenetic analyses were used to study the relationships between H. axyridis OBPs and OBPs from other species of Coleoptera. Quantitative real-time PCR (qPCR) analysis showed that HaxyOBP2, 3, 5, 8, 10, 12, 13, 14, and 15 were highly expressed in antennae of both adult females and males. Moreover, HaxyOBP2, 3, 5, 12, and 15 were more abundantly expressed in antennae than other body parts, while HaxyOBP13 and HaxyOBP14 were expressed predominantly, and at similar levels, in the head and antennae. The other OBP genes were highly expressed in non-olfactory tissues including the thorax, abdomen, legs, and wings. These results provide valuable information for further study of H. axyridis olfaction, which may ultimately enhance its use as a biocontrol agent.

昆虫的嗅觉系统对于调节宿主寻找、交配和产卵等行为至关重要。气味结合蛋白 (OBP) 参与符号化学识别。OBPs 识别并结合气味物质，并将它们输送到位于嗅觉神经元中的气味受体。绣线菊（鞘翅目：瓢虫科）是一种广泛使用的捕食性生物防治剂，可防治多种农林害虫。本研究在H. axyridis 中鉴定了 19 个 OBP基于成人的触角和全身转录组，获得了所有的全长开放阅读框，包括 11 个“经典”OBP、7 个“Minus-C”OBP 和 1 个“Plus-C”OBP。它们编码 125 至 241 个氨基酸的蛋白质，分子量范围为 13.75 至 27.75 kDa，等电点范围为 4.15 至 8.80。系统发育分析被用来研究H. axyridis OBPs 和来自其他鞘翅目物种的 OBPs之间的关系。定量实时PCR（qPCR的）分析表明，HaxyOBP2，3， 5，8，10，12，13，14，和15是高度在天线成年女性和男性的表达。此外，HaxyOBP2、3、5、12和15HaxyOBP13和HaxyOBP14在触角中的表达量高于身体其他部位，而在头部和触角中的表达水平相似。其他 OBP 基因在非嗅觉组织中高度表达，包括胸部、腹部、腿部和翅膀。这些结果为进一步研究刺螟嗅觉提供了有价值的信息，最终可能会增强其作为生物防治剂的用途。