Project description:Diterpenoids and sucrose esters are synthesized in cigar tobacco leave (CTLs) trichomes and secreted onto leaf surface as trichome exudate (TE), contributing to sensory quality.To reveal the mechanism by which TE affects CTLs quality, this study employed the half-leaf method, utilizing tobacco extract as the fermentation medium for cigar tobacco leaves. We analyze the effects of TE on the sensory quality, chemical composition, and microbial communities of cigar tobacco leaves. The levels of degradation products (solanone, isovaleric acid, sclareolide, and sclareol) in the trichome exudate increased, while the levels of reducing sugars, proteins, and tobacco alkaloids decreased. These chemical changes are key factors in enhancing the aroma of smoke, increasing sweetness, reducing harshness, and lowering physiological strength. Metabolic alterations in tobacco leaves led to significantly increased levels of lipids and lipoids, organic acids and their derivatives, and organic heterocyclic compounds. TE enriches Pseudomonas aff. cichorii and Aspergillus aff. intermedius, which degrade nicotine and protein, increase the contents of reducing sugars, amino acids, lipids and lipid-like molucules. This reduces the irritation and physiological strength of CTLs and enhances the sweet taste. Meanwhile, TE is degraded and transformed by P. aff. cichorii to generate aroma compounds, thereby enhancing the aroma quality of cigar tobacco leaves.This study demonstrated that TE not only provides aroma precursors but also modifies leaf chemical components by shaping the microbial community during fermentation, thereby improving CTLs quality and providing a theoretical basis for establishing an artificial fermentation technology system for CTLs based on TE.
Project description:In this study, we have used the comparative transcriptomic and proteomic approaches to decipher the changes in genes and protein abundances in cigar tobacco leaves under LL. In this study, DEGs and DEPs related to glycolysis, starch and sucrose metabolism, tyrosine metabolism, photosynthesis-antenna proteins, and photosynthesis pathways are significantly enriched. This study offers novel insights into both transcriptome and proteome levels response mechanisms under different light intensities.
Project description:Top removal is a widely utilized method in production process of tobacco, but little is known regarding the way it impacts protein and metabolic regulation. In this study, we investigated the underlying processes of alterations in cigar tobacco leaves with and without top removal, using a combined proteomic and metabolomic approach. The results revealed that: (1) Topping significantly affected superoxide anion (O2 -) levels, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) content, (2) In the cigar tobacco proteome, 385 differentially expressed proteins (DEPs) were identified, with 228 proteins upregulated and 156 downregulated. Key pathways enriched included flavonoid biosynthesis, porphyrin and chlorophyll metabolism, cysteine and methionine metabolism, and amino acid biosynthesis and metabolism. A network of 161 nodes interconnected by 102 significantly altered proteins was established, (3) In the cigar tobacco metabolome, 247 significantly different metabolites (DEMs) were identified, with 120 upregulated and 128 downregulated metabolites, mainly comprising lipids and lipid-like molecules, phenylpropanoids and polyketides, organic acids and derivatives, and organic heterocyclic compounds, (4) KEGG pathway enrichment revealed upregulation of proteins such as chalcone synthase (CHS), chalcone isomerase (CHI), naringenin 3-dioxygenase (F3H), and flavonoid 3'-monooxygenase (F3'H), along with metabolites like pinocembrin, kaempferol, trifolin, rutin, and quercetin, enhancing the pathways of 'flavonoid' and 'flavone and flavonol' biosynthesis. This study sheds light on the metabolic and proteomic responses of cigar tobacco after topping.