Metabolomic and ionomic signatures of maize (Zea mays L.) genotypes exhibiting differential temperature tolerance

Maize (Zea mays L.) is a major cereal crop of global importance, valued not only for its nutritional importance but also for its diverse phytochemical composition. Metabolomics offers a comprehensive platform to investigate physiological and biochemical alterations caused by various factors and facilitates the analysis of metabolic alterations associated with varying temperature tolerance in maize genotypes.

In the present study, we employed gas chromatography-mass spectrometry-based untargeted metabolomics, X-ray fluorescence-based elemental profiling, seedling-stage morphological assessment, and priming-mediated germination assays to evaluate three maize genotypes differing in low-temperature (LT) tolerance from the Kashmir Himalayas. A total of 68 metabolites were identified, with unique genotype-specific distributions as follows: 19 in SMC-7 (LT susceptible), 23 in SMC-4 (moderately LT tolerant), and eight in KG-3 (LT tolerant). The rest of the metabolites were shared among the genotypes. KG-3 was characterized by the accumulation of diverse secondary metabolites with potential pharmacological relevance, whereas SMC-4 showed relative enrichment in functional fatty acids and rare sugars. In contrast, SMC-7 exhibited higher levels of polyols and primary sugars that may be associated with general metabolic functions. However, the implications of all these metabolites in terms of dietary and health relevance remains to be further validated. Elemental analysis revealed significant genotype-specific differences in micronutrient allocation, with KG-3 exhibiting elevated levels of K, Fe, and Zn, which could be related to its better agronomic performance and tolerance under LT stress. Morphological evaluation further confirmed KG-3 as highly adaptable to LT conditions. In seed priming experiments, a combined treatment of 50 mmol L^-1 KNO₃ and 8 mmol L^-1 H₂O₂ resulted in the highest germination rate (100%), with SMC-7 and SMC-4 responding more positively than KG-3.

Collectively, these findings highlight the metabolic, nutritional, and physiological bases of differential LT tolerance in maize genotypes, and suggest that genotypes such as KG-3 hold promise for both stress-resilient cultivation and nutritional enhancement in temperate agroecosystems. © 2026 Society of Chemical Industry.