Comprehensive transcriptome and metabolome analysis of the adaptability and detoxification ability of Spodoptera frugiperda larvae to tobacco

Spodoptera frugiperda is among the most significant pests affecting food crops globally. Our findings indicate that the mortality rates of 1st and 2nd instar larvae are significantly higher than those of 3rd instar and older larvae following tobacco consumption. In this study, we employed integrated transcriptomic and metabolomic analyses to investigate the changes in gene expression and metabolic processes in 2nd and 3rd instar larvae after consuming tobacco and maize. Transcriptome analysis revealed that the majority of differentially expressed genes (DEGs) involved in xenobiotic biodegradation and metabolism were upregulated, particularly cytochrome P450s. Metabolomic analysis identified alkaloid metabolites in the bodies of larvae that had fed on tobacco. The 3rd instar larvae that consumed tobacco exhibited increased production of metabolites via cytochrome P450. Correlation analysis of the transcriptome and metabolome demonstrated that, when comparing the 3rd instar larvae fed on tobacco to those fed on maize, both DEGs and differentially accumulated metabolites (DAMs) shared pathways related to cytochrome P450, fatty acid metabolism, and glutathione metabolism. Transcriptome and metabolome analysis shows cytochrome P450 play an important role in the detoxification and adaptability of S. frugiperda larvae to tobacco. This study provides a preliminary explanation of the detoxification metabolism and adaptive mechanisms of S. frugiperda larvae in response to tobacco.