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ORIGINAL RESEARCH article

Front. Plant Sci.
Sec. Plant Metabolism and Chemodiversity
Volume 15 - 2024 | doi: 10.3389/fpls.2024.1473527
This article is part of the Research Topic Plant Specialized Metabolisms: Physiological Responses and Molecular Mechanisms View all 8 articles

LC-MS/MS-Based Metabolic Profiling: Unraveling the Impact of Varying Degrees of Curing on Metabolite Transformations in Tobacco

Provisionally accepted
Kesu Wei Kesu Wei 1Xuling Chen Xuling Chen 2Zhijun Cheng Zhijun Cheng 3Heng Wang Heng Wang 4Feng Wang Feng Wang 5Lei Yang Lei Yang 3Wu Shengjiang Wu Shengjiang 6Yijun Yang Yijun Yang 3Yonggao Tu Yonggao Tu 6Yan WANG Yan WANG 2Chenggang Liang Chenggang Liang 2*
  • 1 Guizhou Academy of Tobacco Science, Guiyang, China
  • 2 Guizhou Normal University, Guiyang, China
  • 3 China Tobacco Hunan Industrial Co. Ltd, Changsha, China
  • 4 Guiyang University, Guiyang, Guizhou Province, China
  • 5 Guizhou Academy of Tobacco Science, Guiyang, Guizhou Province, China
  • 6 Guizhou Institute of Tobacco Science, Guiyang, Guizhou Province, China

The final, formatted version of the article will be published soon.

    The curing process regulates metabolite transformations of leaves and significantly influences the formation of tobacco quality. This study investigated the major physicochemical compositions and metabolic profiles under normal curing (NC), excessive curing (EC), and insufficient curing (IC) treatments. The results indicated that the contents of nicotine, nitrogen, potassium, and chlorine remained stable among treatments, while the sugar content in EC was significantly lower than in IC. LC-MS/MS identified 845 metabolites, with flavonoids as the most abundant class. Comparative analyses identified a series of differentially expressed metabolites (DEMs) among fresh leaf, NC, EC, and IC leaves at the end of 42 °C, 54 °C, and 68 °C, respectively. At the end of 68 °C, 256 up-regulated and 241 down-regulated common DEMs across treatments were isolated in comparison to fresh leaf, underscoring the consistency of metabolic changes during curing. Notably, nonivamide varied markedly across treatments, suggesting its potential as a key curing indicator. NC_68°C displayed 11 up-regulated and 17 down-regulated unique DEMs, differing from EC_68°C and IC_68°C, suggesting their potential availability in evaluating tobacco leaf quality. KEGG pathway analysis revealed temporal shifts in metabolic pathways, particularly those involved in secondary metabolite biosynthesis (such as flavonoids, flavones, flavonols) and amino acid metabolism, during the transition from yellowing to color-fixing. Correlation analysis isolated the top 25 DEMs correlated with curing degree and stage, which might play pivotal roles in the curing process and could serve as potential biomarkers for assessing curing degree and stage. Specifically, D-(+)-cellobiose displayed the strongest negative correlation with curing degree, while 5,7-dihydroxychromone exhibited the highest positive correlation coefficient. Furthermore, curcurbitacin IIa showed the highest positive correlation with curing stage, followed by hesperetin and 8-shogaol. Additionally, random forest analysis emphasized morellic acid as a core molecular metabolite across curing degrees, suggesting its potential as a biomarker. Debiased sparse partial correlation (DSPC) network analysis further pinpointed hispidulin as a key metabolite, underscoring its significance in elucidating flavonoid metabolism during the curing process. Collectively, this study enhances the understanding of metabolite transformations underlying tobacco curing processes and provides a valuable reference for optimizing curing strategies to achieve desired outcomes.

    Keywords: Tobacco, Curing degree, Curing stage, Metabolite transformation, Flavonoids, sugar

    Received: 31 Jul 2024; Accepted: 16 Oct 2024.

    Copyright: © 2024 Wei, Chen, Cheng, Wang, Wang, Yang, Shengjiang, Yang, Tu, WANG and Liang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Chenggang Liang, Guizhou Normal University, Guiyang, China

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