类黄酮和类胡萝卜素代谢物的变化特征及其与褪色的关系

Variations of flavonoid and carotenoid metabolites in cured tobacco and their relationships with color fading

为探究原烟褪色过程中代谢物的变化特征及其与褪色的关系,以易褪色烤烟品种云烟87为供试材料,采用200μmol/(m^(2)·s)光照强度分别处理0、15、30 d得到不同褪色程度的烟叶,观察原烟褪色前后的色差及类黄酮和类胡萝卜素代谢物的变化特征,分析其与原烟褪色的关系。结果表明:①原烟在褪色过程中表现为L^(*)值先降低后升高、a^(*)和b^(*)值不断降低的趋势。②不同褪色处理的原烟中共检出4987种、共25类代谢物,褪色越严重,差异代谢物及下调差异代谢物数量越多。③代谢通路分析结果表明,原烟褪色过程中,类黄酮和类胡萝卜素代谢物的转化代谢途径均显著富集,说明这两条通路与烟叶颜色的变化密切相关;通过定量分析,发现类黄酮和类胡萝卜素代谢物含量(质量分数)与烟叶颜色指标之间均存在较强的相关关系,类黄酮和类胡萝卜素代谢物的降解和转化与原烟红度值和黄度值的降低关系密切,可能是造成原烟褪色的主要内因。

To investigate the characteristics of metabolites in cured tobacco during color fading and their relationship,the easily fading flue-cured tobacco variety Yunyan 87 was treated under 200μmol/(m^(2)·s)light intensity for 0,15,and 30 d to obtain tobacco leaves with different degrees of fading.The color differences and the characteristic flavonoid and carotenoid metabolites before and after color fading were observed,and their relationships with the degree of fading were analyzed.The results showed that:1)The L^(*) value first decreased and then increased,and the a^(*) and b^(*) values decreased continuously during the fading process of cured tobacco.2)A total of 4987 metabolites belonging to 25 categories were detected in the cured tobacco after different fading treatments.The more severe the fading was,the higher the amounts of differential metabolites and down-regulated differential metabolites.3)The results of metabolic pathway analysis showed that the transformation metabolic pathways of flavonoid and carotenoid metabolites were significantly enriched during the fading process,indicating that these two pathways were closely related to the development of tobacco color.Quantitative analysis revealed that there were strong correlations between the flavonoid and carotenoid metabolite contents(mass fractions)and the color indexes of the cured tobacco leaves.The degradation and transformation of flavonoid and carotenoid metabolites were closely related to the decrease of redness and yellowness values of the cured tobacco,which might be the main internal cause of cured tobacco fading.