Metabolomics revealed the dynamic changes of metabolites during the ripening of upper tobacco leaves and the metabolic markers for ripeness determination
Bingye Yang, Jianwei Wang, Xiangfu Liu, Xiaodong Huang, Huaxin Dai, Jianli Liu, Yanling Zhang
Abstract
To elucidate the metabolic dynamics underlying the ripening process of upper tobacco leaves, we conducted metabolomic analyses using gas chromatography-mass spectrometry (GC-MS) for two consecutive years (2022–2023). Orthogonal partial least squares discriminant analysis (OPLS-DA) identified 83 (2022) and 48 (2023) differential metabolites, with 21 differential metabolites consistently detected across both experimental years. Among these, threonine, cysteine, proline, ribitol and arabitol gradually decreased during ripening, whereas nornicotine, anatabine and nicotine exhibited increasing trends. Pathway enrichment analysis showed that biosynthesis of amino acids was the most significantly enriched pathway for differential metabolites in both years. Notably, we found that D-malic acid and α-tocopherol were potential metabolic markers to assess leaf ripeness. Correlation analysis showed that relative humidity and maximum temperature had a strong effect on metabolite content during the ripening process of upper tobacco leaves, while lowest temperature had the least effect. These findings provide crucial insights into metabolic reprogramming during tobacco leaf ripening and establish a foundation for optimizing harvest timing based on metabolic signatures.