【目的】 为深入了解和探究明确草地贪夜蛾Spodoptera frugiperda对杀虫剂甲维盐的解毒机制。【方法】 对草地贪夜蛾敏感度下降品系和敏感品系3龄幼虫进行转录组测序分析和代谢组学分析，并对转录组与代谢组进行联合分析。【结果】 转录组中鉴定出222个差异表达基因，其中76个基因上调，146个基因下调（P<0.05）。其中草地贪夜蛾敏感度下降品系的11个代谢相关基因较敏感品系升高，转录水平升高2.0倍以上。在差异代谢物中定位到尿苷二磷酸葡萄糖、L-谷氨酸、γ-氨基丁酸、L-苏氨酸、L-半胱氨酸等代谢物，其中γ-氨基丁酸显著上调（P<0.05），差异倍数为2.47；L-谷氨酸显著下调（P<0.05），差异倍数为0.69。转录组与代谢组联合分析结果表明，差异基因和差异代谢物主要共同富集于戊糖和葡萄糖酸盐的相互转化、氨基酸-tRNA生物合成以及丙氨酸、天门冬氨酸和谷氨酸代谢等通路。谷氨酸代谢途径富集到4个差异表达基因编码3种关键酶，包括谷氨酸合成酶、4-氨基丁酸转氨酶和谷氨酸脱羧酶。该途径富集到4种代谢产物，其中天门冬氨酸、2-氧化戊二酸和γ-氨基丁酸含量显著增加，L-谷氨酸含量显著降低。敏感度下降品系的谷氨酸脱羧酶活性升高，催化L-谷氨酸合成更多抑制性神经递质γ-氨基丁酸。【结论】 谷氨酸代谢途径可能在草地贪夜蛾对甲维盐的解毒过程中起到重要的作用。本研究结果为进一步研究草地贪夜蛾对杀虫剂的解毒机制提供了依据。

[Objectives]  To investigate and clarify the mechanism used by Spodoptera frugiperda to detoxify the insecticide emamectin benzoate. [Methods]  Transcriptome sequencing and metabolomic analysis were performed on 3rd instar S. frugiperda larvae from an emamectin benzoate-hyposensitive strain (EB-HS) and a sensitive strain (SS). The transcriptome and metabolome were analyzed jointly. [Results]  Two hundred and twenty-two differentially expressed genes (DEGs) were detected in the transcriptome, of which 76 were up-regulated and 146 down-regulated (P < 0.05). Among these, eleven metabolism-related genes were more common in the EB-HS than in the SS, and transcript levels were more than 2.0-fold higher in the EB-HS. Identified differential metabolites include uridine diphosphate glucose, L-glutamic acid, gamma- aminobutyric acid, L-threonine and L-cysteine. Gamma-aminobutyric acid was significantly up-regulated with a time difference of 2.47 and L-glutamic acid was significantly down-regulated with a difference multiple of 0.69. The combined analysis of the transcriptome and metabolome indicates that DEGs and DMs are mainly enriched in pentose and glucuronate interconversion, aminoacyl-tRNA biosynthesis, alanine, aspartate and glutamate metabolism, and other pathways. The glutamate metabolic pathway was enriched to four DEGs encoding three key enzymes, including glutamate synthetase, 4-aminobutyrate aminotransferase and glutamate decarboxylase. Four metabolites were enriched by this pathway, which significantly increased aspartic acid, 2-oxoglutarate and gamma-aminobutyric acid content, whereas L-glutamic acid content significantly decreased. Glutamate decarboxylase activity increased in the EB-HS, catalyzing L-glutamate synthesis of the more inhibitory neurotransmitter gamma-aminobutyric acid. [Conclusion]  The glutamate metabolism pathway may play an important role in the detoxification of emamectin benzoate by S. frugiperda. These findings provide a basis for further research on the mechanism responsible for insecticide detoxification in this species.