Metabolic Differences and Formation Reasons of Open Fire Curing Tobacco Leaves Based on Metabolomics Analysis

Purpose Using metabolomics technology to analyze the metabolic differences and formation reasons of bright tobacco leaves under open fire curing.

Method Using the tobacco variety K326 as experimental material, conducting a comparative experiment between open fire curing (X) and flue-curing (CK), analyzing the metabolic differences of the two processing methods using metabolomics technology, and summarizing the formation reasons of the differences.

Results The KEGG enrichment results showed that in the X-38 VS. CK-38 comparison group, linoleic acid metabolism and plant hormone signal transduction were the top two significantly enriched pathways; in the X-42 VS. CK-42 comparison group, glycolysis/gluconeogenesis and amino acid biosynthesis were the top two significantly enriched pathways; in both the CK-42 VS. CK-38 comparison group and the X-42 VS. X-38 comparison group, linoleic acid metabolism and nucleotide metabolism were the top two significantly enriched pathways. The up-regulated metabolites in all four comparison groups included free fatty acids, amino acids and derivatives, phenolic acids, sugars, organic acids, alkaloids, nucleotides and derivatives, etc.

Conclusion The different metabolites of tobacco leaves under open fire curing include a large amount of acidic metabolites. The possible reason for the difference is that open fire curing can cause additional smoke stress and photo-thermal radiation stress on tobacco leaves, and tobacco leaves under open fire curing have a higher moisture content than those of flue-curing, which is conducive to substance conversion.