Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China.
International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China.
Pest Manag Sci. 2021 Jul;77(7):3068-3079. doi: 10.1002/ps.6352. Epub 2021 Apr 3.
Odorant-binding proteins (OBPs) in insects contribute to the sensitivity of the olfactory system and connect external odorants to olfactory receptor neurons. Determination of the chemosensory functions in Diaphorina citri, a vector of the citrus Huanglongbing pathogen, may help in developing a potential target for pest management.
Diaphorina citri showed dose-dependent electroantennogram recording (EAG) responses to 12 host plant volatiles. A two-choice behavioral trap experiment showed that four compounds (methyl salicylate, linalool, citral and R-(+)-limonene) that elicited high EAG responses also had significant attraction to adults. The expression profiles induced by these compounds were detected in nine OBP genes, DcitOBP1-9. DcitOBP3, DcitOBP6 and DcitOBP7 commonly showed significant upregulation or downregulation compared with the control. Microscale thermophoresis (MST) showed that the recombinant protein DcitOBP7 had high in vitro binding affinities (K < 10 μm) to methyl salicylate, linalool and R-(+)-limonene, and moderate binding affinity to citral with a K value of 15.95 μm. Furthermore, RNA interference (RNAi)-suppressed messenger RNA (mRNA) expression of DcitOBP7 resulted in a significant reduction in EAG activity and in adult D. citri behavioral responses to tested volatiles and the preferred host, Murraya paniculata. The hydrophilic residue Arg107 of DcitOBP7 may have a key role in binding odorants via formation of hydrogen bonds.
These results show that DcitOBP7 plays an important role in the olfactory response. This finding may provide new insight into the functions of OBP families in D. citri and aid in the development of safe strategies for managing D. citri populations. © 2021 Society of Chemical Industry.
昆虫的气味结合蛋白（OBPs）有助于嗅觉系统的敏感性，并将外部气味与嗅觉受体神经元连接起来。确定柑橘黄龙病病原体的载体柑橘木虱的化学感觉功能，可能有助于开发潜在的害虫管理目标。
柑橘木虱对 12 种寄主植物挥发物表现出剂量依赖性的触角电位记录（EAG）反应。双选择行为陷阱实验表明，四种化合物（水杨酸甲酯、芳樟醇、柠檬醛和 R-(+)-柠檬烯）引起高 EAG 反应，对成虫也有显著的吸引力。在 9 个 OBP 基因（DcitOBP1-9）中检测到这些化合物诱导的表达谱。与对照相比，DcitOBP3、DcitOBP6 和 DcitOBP7 通常表现出显著的上调或下调。微量热泳动（MST）显示，重组蛋白 DcitOBP7 对水杨酸甲酯、芳樟醇和 R-(+)-柠檬烯具有高体外结合亲和力（K < 10 μm），对柠檬醛具有中等结合亲和力，K 值为 15.95 μm。此外，DcitOBP7 的 RNA 干扰（RNAi）抑制信使 RNA（mRNA）表达导致 EAG 活性显著降低，以及成年柑橘木虱对测试挥发物和首选寄主植物芸香的行为反应显著降低。DcitOBP7 的亲水残基 Arg107 可能在通过形成氢键结合气味物质方面发挥关键作用。
这些结果表明 DcitOBP7 在嗅觉反应中起重要作用。这一发现可能为 OBP 家族在柑橘木虱中的功能提供新的见解，并有助于开发安全的柑橘木虱种群管理策略。 © 2021 化学工业协会。
