UPLC-MS/MS-based differential analysis of seed primordial metabolism in different sorghum varieties

Objective: This study aims to screen brewing sorghum materials from sorghum germplasm resources and conduct differential analysis, in order to address the issues of cultivar degradation and varietal homogenization. Methods: UPLC-MS/MS-based metabolomics was employed to analyze primary metabolites in five sorghum cultivars. Multivariate statistical methods, including Principal Component Analysis (PCA) and Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA), were used in combination with metabolic pathway enrichment analysis to systematically explore the effects of varietal differences on sorghum primary metabolite profiles. Results: A total of 503 metabolites were detected in this study. Statistical analyses indicated that sorghum cultivar had a significant influence on both the composition and abundance of metabolites. The OPLS-DA model revealed distinct clustering among the cultivar samples, suggesting that primary metabolic profiles exhibit cultivar specificity. Metabolic pathway enrichment analysis further revealed that the metabolic differences among cultivars were mainly concentrated in pathways related to amino acids, flavonoids, and phenolic acids, with changes in flavonoid compounds being particularly prominent. This study not only provides a metabolomic basis for sorghum cultivar identification, but also offers scientific reference for sorghum cultivation and the breeding of brewing-specific cultivars. Conclusion: Based on UPLC-MS/MS metabolomics technology, this study analyzed the primary metabolites of five sorghum cultivars and detected a total of 503 metabolites. Comparative analyses among samples from different regions (hyz vs. jinl, hyz vs. jinnl, hyz vs. lnh, hyz vs. lz19, jinl vs. lz19, jinnl vs. jinl, jinnl vs. lz19, lnh vs. jinl, lnh vs. jinnl, lnh vs. lz19) identified 175, 179, 152, 175, 123, 187, 153, 194, 220, and 170 significantly different metabolites, respectively, indicating substantial differences in metabolic profiles among sorghum cultivars. Further analysis showed that varietal differences significantly affected metabolite composition and relative abundance, and these specific metabolites may serve as potential biomarkers for cultivar identification. KEGG pathway enrichment analysis indicated that flavonoid biosynthesis was the major differential metabolic pathway, with particularly notable changes in flavonoid compounds. These findings suggest that flavonoid metabolism plays a key role in cultivar-specific metabolic regulation and provides valuable insight into the molecular mechanisms underlying sorghum quality formation.