不同品种烤烟成熟期糖代谢酶活性及基因的表达分析

为了探究不同品种烤烟成熟期糖代谢的变化规律，明确烟叶品质形成的分子作用机理。以烤烟品种秦烟96、豫烟6号和K326为试验材料，测定分析了烤烟成熟期水溶性糖组分（葡萄糖、果糖、麦芽糖、蔗糖、还原糖和可溶性总糖）含量、糖代谢关键酶活性及基因表达的变化。结果表明，3个品种烤烟水溶性糖组份含量变化趋势基本一致，各水溶性糖（蔗糖除外）含量呈先升高后降低的变化趋势，烟叶成熟时其含量达到峰值；蔗糖含量呈双峰波动，烟叶成熟时蔗糖含量较低。烟叶打顶至适熟阶段，SPS和AI酶活性对烟叶中水溶性糖的积累贡献最大，NtINV对烟叶糖代谢起主要调控作用；当烟叶由适熟至过熟时，AI酶活性主要参与烟叶糖代谢活动，而SS和SPS则对蔗糖积累起重要作用，NtSS和NtSPS对烟叶糖代谢起主要调控作用。同一生态环境和栽培条件下，豫烟6号内含物质充实，具有较高的水溶性糖分含量，SPS和AI酶活性的差异可能是造成烟叶糖组分及含量不同的重要原因。

Dynamic Analysis of Sugar Metabolic Enzyme Activities and Gene Expression in Different Flue-cured Tobacco Varieties at Mature Stage

In order to explore the changes of sugar metabolism in different varieties of flue-cured tobacco, clarifying the molecular mechanism of the formation of tobacco leaf quality, the flue-cured tobacco varieties Qinyan 96, Yuyan 6 and K326 were taken as the sample materials to determine the changes of water-soluble sugar components (glucose, fructose, maltose, sucrose, reducing sugars, and total soluble sugars), key enzyme activities in sugar metabolic and gene expression changes at mature stage. The results showed that the trend of change in water soluble sugar content in the three varieties of flue-cured tobacco was basically the same. The contents of water soluble sugars (except sucrose) first increased and then decreased, reaching the peak when tobacco leaves matured. The sucrose content showed a bimodal fluctuation, and the sucrose content was the lowest when the tobacco was mature. The activity of SPS and AI enzymes contributed the most to the accumulation of water-soluble sugars in tobacco leaves from topping to proper maturity. NtINV played a major role in regulating sugar metabolism in tobacco leaves. When tobacco leaves were from ripe to overripe status, AI enzyme activity was mainly involved in tobacco sugar metabolism, while SS and SPS played an important role in sucrose accumulation. NtSS and NtSPS played a major role in regulating sugar metabolism. Under the same ecological environment and cultivation conditions, the content of metabolites in Yuyan 6 was enriched and had high water-soluble sugar content. The difference of SPS and AI enzyme activity may be an important reason for the different sugar components and content of tobacco leaves.