Cold Tolerance Differences Between the Widely Used Model S. lycopersicum Cultivars and the Wild Species S. lycopersicoides: Role of Fatty Acid Profile and CBF Genes

Late spring frosts and transient cold spells constrain tomato productivity. This study presents a comparative analysis of the chilling response of two Solanum lycopersicum cultivars, MoneyMaker (MM) and Micro-Tom (MT), and the wild relative S. lycopersicoides. The assessment integrated physiological parameters, such as electrolyte leakage and PSII efficiency, expression levels of CBF1–3 genes (via qPCR), and fatty acid composition dynamics of membrane lipids (via gas-liquid chromatography-mass spectrometry). The results revealed distinct response strategies. S. lycopersicoides exhibited comprehensive tolerance and was coordinated across biological levels. Its key mechanisms include superior membrane integrity, sustained PSII photochemical efficiency, stable upregulation of CBF genes (with predominant CBF3 induction), and consistently high α-linolenic acid content. This integration prevented membrane damage and sustained photosynthesis. Conversely, the MM cultivar displayed high sensitivity, characterized by transient CBF1 upregulation, an absence of adaptive lipid remodelling, rapid membrane damage, and severe photoinhibition, explaining its poor recovery. The MT genotype demonstrated an intermediate phenotype, featuring delayed but persistent CBF activation, and the partial lipid profile shifted toward the wild-type pattern, indicating a partial adaptive capacity for membrane adjustment. These findings establish S. lycopersicoides as a vital genetic resource for breeding cold-tolerant tomatoes, while MT provides a model for studying adaptation mechanisms in cultivated varieties.