Integrated proteomic analysis reveals differential remodelling of defense responses in potato to herbivory by Phthorimaea operculella.

Plants rely on both transcriptional reprogramming and post-translational machinery to regulate their responses to biotic stress. While transcriptome-wide dynamics underlying plant defense against insect herbivores have been extensively documented, systematic investigations into protein-level regulation and integrative analyses of these multi-layered regulatory networks remain limited. In this study, we employed quantitative proteomics and phospho-proteomics to characterize the protein-level responses of potato plants to attacks by Phthorimaea operculella. A total of 60 differentially expressed proteins (DEPs) and 56 differentially phosphorylated proteins (DPPs) were identified in potato leaves at 5 h post-herbivory. Among them, 88.3% of DEPs showed upregulated protein accumulation post herbivory, whereas 92.8% of DPPs showed downregulated protein phosphorylation post herbivory. Integrated transcriptomic and proteomic analyses revealed a multi-layered regulatory complexity in the herbivory response, with only approximately 50% of the observed proteomic changes being explained by transcriptional regulation. Notably, CDPK2 (Calcium-Dependent Protein Kinase 2) was found to be dually regulated at both transcriptional and phosphorylation levels following herbivory. Our functional analyses in Nicotiana benthamiana suggest that CDPK2 enhances plant herbivore resistance by promoting jasmonic acid (JA) biosynthesis and likely suppressing salicylic acid (SA) signaling activation during herbivory response. Collectively, this study provides integrated insights into mechanisms underlying potato herbivore defense and identifies an important regulatory factor.