Analysis Of Polyphenols Contents And Quality Of Tobacco Leaf In Different Varieties Of Tobacco In Southeastern Guizhou

This experiment was carried out in the Shibing County experimental field in southeast Guizhou Province in 2018.The test materials were Yun 87,K326 and Yuyan No.11.Test on phenylalanine,chlorogenic acid,rutin,total phenolic content,phenylalanine ammonia-lyase(PAL),cinnamic acid-4-hydroxylase(C4H),4-coumaric acid ligase(4CL),quinic acid hydroxycinnamoyltransferase(HQT),chalcone synthase(CHS)and polyphenol oxidase(PPO)activity and gene expression and tobacco quality were analyzed to explore the metabolism of polyphenols Regularity provides a useful reference for the regulation of polyphenols in flue-cured tobacco and improves the quality of tobacco leaves.The main findings are as follows:(1)The content of phenylalanine in Yunyan 87 was significantly lower than that of Yuyan No.11,slightly lower than K326,while the main polyphenols chlorogenic acid and rutin were significantly higher than Yuyan No.11 and K326,further to polyphenols.The activity of key enzymes in the metabolism of the substances was found to be significantly higher than that of Yuyan No.11 and K326 except for HQT activity,and the activities of PAL,C4H,4CL and CHS in Yunyan 87 tobacco leaves.Therefore,the content of phenylalanine in the substrate had no significant effect on the content of chlorogenic acid and rutin,the main polyphenols,and was mainly affected by the activities of PAL,C4H,4CL and CHS,the key enzymes of polyphenols.(2)Studying the key enzyme activities and gene expression levels of polyphenols metabolism,it was found that the relative expression levels of the enzymes corresponding to the enzymes were not completely consistent.The relative gene expression levels of C4H and 4CL in Yun 87 were significantly higher than that of Yuyan 11 and K326.The activities of C4H and 4CL were also significantly higher than that of Yuyan 11 and K326.The relative expression of HQT gene in K326 was significantly higher than that in Yun 87 and Yuyan No.11,its HQT enzyme activity was also significantly higher than Yun 87 and Yuyan No.11,and the above enzyme activity was consistent with its relative expression.The relative expression of PAL and CHS genes in Yunyan 87 was significantly lower than that of Yuyan No.11,and its PAL and CHS activities were significantly higher than that of Yuyan No.11,and its enzyme activity and gene relative expression were not consistent.Therefore,the enzyme activity is not directly related to the relative gene expression level of the enzyme..(4)From the chemical composition analysis of each variety,K326 nicotine and total nitrogen content are higher,cloud 87 and Y11 have higher total sugar and reducing sugar content,cloud 87 potassium content is higher,chlorine content is lower,potassium chloride It is relatively high;from the sensory quality evaluation of each variety,the scores of Yunyan 87 are higher than K326 and Yuyan No.11,especially the aroma and irritancy;Compared with the chromaticity,foliar structure,luster and leaf structure,the scores of the appearance quality of Yunyan 87 tobacco leaves were higher than those of K326 and Yuyan No.11,especially in terms of oil content,flexibility and color.Significantly higher than K326 and Yuyan No.11.With comprehensive chemical composition,sensory quality and appearance quality,Yun 87 tobacco leaves perform better.