Proteomic changes associated with the initiation and termination of aestivation in the cabbage stem flea beetle

The cabbage stem flea beetle (CSFB, Psylliodes chrysocephala) is a major pest of oilseed rape crops and exhibits obligatory adult aestivation that coincides with the summer season. The aestivation in CSFB is characterized by metabolic suppression, cessation of feeding, and reproductive activities. Previous investigations have employed RNA-seq to explore gene expression changes associated with aestivation, providing initial insights into the molecular pathways. However, studies assessing proteomic changes during aestivation in this species and insects more broadly have been lacking. In this study, we conducted a comprehensive quantitative proteomic analysis of adult CSFB at four time points: aestivation preparatory phase (pre-aestivation, day 5), early (day 15) and late (day 30) aestivation maintenance, and post-aestivation (day 55), to investigate proteomic changes associated with aestivation. We found that proteins related to the central dogma decreased in abundance, and metabolism-related proteins were altered during the initiation of aestivation. The proteomic changes during aestivation were minor and included a reduction in mitochondrial proteins. Notably, the proteolysis-related proteins were enriched at the termination of aestivation. Interestingly, we observed discrepancies between our previous RNA-seq results and the proteomic data, particularly in the genes that increased in abundance during aestivation compared to post-aestivation. This highlights the importance of proteomic analysis for a more complete understanding of molecular mechanisms underlying aestivation. Body composition measurements showed that TAG and chitin levels peaked, while ATP and glucose got depleted during aestivation, following the changes in proteins belonging to different biological pathways.