Integrative lipidomic and proteomic analysis reveals the mechanisms of freezing tolerance in Meloidogyne incognita eggs

The accelerated northward shift of the overwintering boundary of Meloidogyne incognita suggests that this nematode has acquired enhanced capacity for low-temperature adaptation. Increased freeze tolerance in eggs is considered a key factor contributing to this range expansion. Although global climate change plays a role, low-temperature acclimation during the autumn-winter transition is also thought to influence this process. In this study, integrated analysis using untargeted metabolomics and proteomics revealed that acclimation at 4 °C significantly increased the accumulation of metabolites such as acylcarnitine CAR(20:0), triacylglycerol TG, Bis(monoacylglycero)phosphate BMP(36:2), and phosphatidylinositol PI(13:1_18:2). Conversely, levels of fatty acid FA(19:0, 20:0, and 22:0), diacylglycerol DG(16:0_16:0), and ceramide-1-phosphate CerP(17:0;2O/16:0) decreased. Proteomic analysis further demonstrated downregulation of proteins including glycerol-3-phosphate dehydrogenase (GPDH) and long-chain-fatty-acyl-CoA ligase (FACL), alongside upregulation of phospholipid/glycerol acyltransferase and phosphatidic acid phosphatase (PAP). Correlation analysis integrating lipidomic and proteomic changes helped establish a more robust metabolic and cellular regulatory network. As the first whole-organism lipid and protein profiling in this species, these findings, despite limited current integration, provide a mechanistic framework for pest cold adaptation and pinpoint specific molecular targets within overwintering metabolic pathways.