采后烟叶碳代谢的动态变化分析

Dynamic Analysis of Carbon Metabolism in Tobacco Leaves after Harvest

为探究采后离体烟叶内碳代谢的变化规律,以烤烟品种豫烟12号和秦烟96为供试材料,测定采后不同时段烟叶淀粉、总糖和还原糖含量变化,并对淀粉和糖代谢相关基因进行实时荧光定量PCR分析。结果表明,秦烟96采后烟叶淀粉含量显著高于豫烟12号,烟叶采后0~30 h,淀粉含量逐渐下降,总糖和还原糖含量逐渐升高,且糖含量在采后12 h后增加速率变快。秦烟96鲜烟叶中淀粉和糖代谢相关基因的表达量高于豫烟12号,而淀粉分解相关基因Ntα-amylase和Ntβ-amylase表达量低于豫烟12号。烟叶采后30 h内,淀粉合成相关基因Nt AGPS1、Nt AGPS3和直链淀粉合成关键基因Nt GBSS1表达量逐渐下调;支链淀粉合成的相关酶基因表达量变化呈无序增降模式;淀粉分解代谢和糖代谢相关酶基因的表达量或呈先升后降趋势,或呈逐渐上升趋势。Nt AGPS1和Nt GBSS1表达量变化与采后烟叶中淀粉和糖含量变化相关性显著。同一生态条件下,豫烟12号和秦烟96采后烟叶淀粉和糖代谢规律存在差异,其中Nt AGPS1和Nt GBSS1可能是采后离体烟叶碳代谢的关键调控基因。

To explore the molecular mechanism of carbon metabolism in tobacco leaves after harvest,the flue-cured tobacco varieties“Yuyan 12”and“Qinyan 96”were taken as the sample materials to determine the changes of starch,total sugar,and reducing sugar contents,and the expression levels of starch and sucrose metabolism related genes in tobacco leaves after harvest were analyzed by real-time fluorescence quantitative PCR.The results indicated that the starch content of“Qinyan 96”was significantly higher than that of“Yuyan 12”.Starch content decreased gradually after harvested for 0-30 h,while total sugar and reducing sugar gradually increased,and sugar content increased rapidly after 12 h.The expression of NtAGPS3,NtGBSS1,NtSS1,NtSS2,NtSBE1,NtSBE2,NtISO2,NtISO3,NtSP,NtSPSA,NtSPSB,NtSPSC,NtSPP1,NtSPP2,NtSuS and NtVIN1 in fresh tobacco leaves of“Qinyan 96”was significantly higher than that of“Yuyan 12”,while the expression of Ntα-amylase and Ntβ-amylase was significantly lower than that of“Yuyan 12”.The expression levels of NtAGPS1,NtAGPS3 and NtGBSS1 decreased rapidly after harvested for 0-30 h;the expression levels of amylopectin synthesis related genes showed disordered increasing and decreasing;the expression of NtSR1,Ntα-amylase,Ntβ-amylase,NtSP,NtSPSA,NtSPSB,NtSPSC,NtSPP1,NtSPP2,NtSuS and NtVIN1 showed the trend of ascending first then descending,or increasing gradually.The expression levels of NtAGPS1 and NtGBSS1 were significantly correlated to the changes of starch and sugar contents.These results suggested that there are some differences in starch and sugar metabolism between“Yuyan 12”and“Qinyan 96”,and NtAGPS1 and NtGBSS1 might be the key genes regulating the carbon metabolism in tobacco leaves after harvest.