Integrative physiological, transcriptomic, and metabolomic analyses reveal novel insights into quality maturation in...

Newly harvested wheat kernels undergo a critical after-ripening period that impairs storage stability and limits its utilization, while the key indicators and metabolic pathways underlying quality improvement in wheat grains remain poorly unclear. This study analyzed wheat kernels stored at 25 °C for 120 days using physiological, transcriptomic, and metabolomic approaches. Results showed germination rate, along with activities of catalase, NADPH oxidase, glucose-6-phosphate dehydrogenase and malate dehydrogenase, underwent significant changes during the first 60 days before stabilizing. In contrast, key quality parameters, including glutenin content, gluten index, lactic acid solvent retention capacity, disulfide bonds content and farinograph properties, stabilized after 80 d. Moreover, multi-omics analysis further revealed that the after-ripening process induced significantly alterations in multiple metabolic pathways, especially the 'starch and sucrose metabolism', 'nitrogen metabolism', and 'amino acid metabolism', up-regulated the expression of key genes (TPP, GAD, PAL, PD, ASL, NAGK and AGM) involved in them, as well as increased the levels of trehalose, D-gluconic acid and phenylalanine and decreased the content of sucrose, L-glutamate, and tyrosine, ultimately refine the maturation of wheat grain quality. These changes synergistically enhanced gluten network and starch functionality, providing molecular insight into quality maturation and scientific support for improving wheat storage and processing quality.