The tobacco cutworm Spodoptera litura (Lepidoptera: Noctuidae) is a polyphagous pest with a highly selective and sensitive chemosensory system involved in complex physiological behaviors such as searching for food sources, feeding, courtship, and oviposition. However, effective management strategies for controlling the insect pest populations under threshold levels are lacking. Therefore, there is an urgent need to formulate eco-friendly pest control strategies based on the disruption of the insect chemosensory system. In this study, we identified 158 putative chemosensory genes based on transcriptomic and genomic data for S. litura, including 45 odorant-binding proteins (OBPs, nine were new), 23 chemosensory proteins (CSPs), 60 odorant receptors (ORs, three were new), and 30 gustatory receptors (GRs, three were new), a number higher than those reported by previous transcriptome studies. Subsequently, we constructed phylogenetic trees based on these genes in moths and analyzed the dynamic expression of various genes in head capsules across larval instars using quantitative real-time polymerase chain reaction. Nine genes–SlitOBP8, SlitOBP9, SlitOBP25, SlitCSP1, SlitCSP7, SlitCSP18, SlitOR34, SlitGR240, and SlitGR242–were highly expressed in the heads of 3- to 5-day-old S. litura larvae. The genes differentially expressed in olfactory organs during larval development might play crucial roles in the chemosensory system of S. litura larvae. Our findings substantially expand the gene inventory for S. litura and present potential target genes for further studies on larval feeding in S. litura.

中文翻译：

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斜纹夜蛾幼虫头部的化学感应基因

烟草地老虎斜纹夜蛾鳞翅目（鳞翅目：夜蛾科）是一种多食性害虫，具有高度选择性和敏感的化学感应系统，参与复杂的生理行为，如寻找食物来源、取食、求偶和产卵。然而，缺乏将害虫种群控制在阈值水平以下的有效管理策略。因此，迫切需要制定基于昆虫化学感应系统破坏的生态友好型害虫防治策略。在这项研究中，我们根据转录组学和基因组数据确定了 158 个推定的化学感应基因斜纹夜蛾, 包括 45 种气味结合蛋白 (OBPs, 9 个是新的), 23 个化学感觉蛋白 (CSPs), 60 个气味受体 (ORs, 3 个是新的), 和 30 个味觉受体 (GRs, 3 个是新的), 数量高于那些以前的转录组研究报道。随后，我们基于飞蛾中的这些基因构建了系统发育树，并使用定量实时聚合酶链反应分析了幼虫头囊中各种基因的动态表达。九个基因——狭缝OBP8,狭缝OBP9,狭缝OBP25,狭缝CSP1,狭缝CSP7,狭缝CSP18,SlitOR34,狭缝GR240， 和狭缝GR242– 在 3 至 5 天大的孩子的头脑中高度表达斜纹夜蛾幼虫。幼虫发育过程中嗅觉器官中差异表达的基因可能在斜纹夜蛾幼虫。我们的发现大大扩展了基因库斜纹夜蛾并为进一步研究幼虫摄食提供潜在的靶基因斜纹夜蛾.