Licorice Hmgr, Sqs1 And Beta Contents As Gene Cnvs And Glycyrrhizic Acid, Licorice Correlation Studies

As the most frequently used Chinese medicine in TCM clinical prescription, the roots of Glycyrrhiza uralensis Fisch. are extensively used in worldwide. The amount of glycyrrhizin, which is the key therapeutic compound of the herb, is an important indicator for the evaluation of the licorice quality. However, the amout of glycyrrhizin in cultivated licorice is lower than the wild licorice, which has influenced the clinic efficacy and drug quality of licorice. Therefore, improving the quality of cultivated licorice has become the key to solve this problem. Revealing the molecular mechanism of the biosynthetic pathway of glycyrrhizin will provide an efficient route for improving the quality of cultivar of Glycyrrhiza uralensis.In our previous studies, we have found the single nucleotide polymorphisms (SNPs) of functional genes can be used to explain why there were differences in the content of glycyrrhizin in different licorice plants, but it can not fully reveal the molecular mechanism of the biosynthetic pathway of glycyrrhizin. In addition, we have also analyzed the correlations between the copy number variations (CNVs) of the functional genes and morphological characteristics of licorice.In this paper, the conditions of real-time PCR were improved and used to determine the copy number of functional genes, HMGR, SQS1and β-AS. HPLC was used to analyse the content of glycyrrhizin.6different groups with different copy number of functional genes were determined. And the relationship between CNVs of the functional genes and the level of glycyrrhizin was revealed.The results of this paper are as follows:1. The conditions of real-time PCR were improved and used to determine the copy number of functional genes, HMGR, SQSI and β-AS.2. There were two types of copy number, one copy or two copies, present in the62samples. For HMGR, the copy number in55samples was one copy (88.7%), while only in7samples the copy number was two copies. For SQS1, the copy number in51samples was two copies (82.3%), while only in11samples the copy number was one copy. For β-AS, the copy number in55samples was two copies (88.7%), while only in7samples the copy number was one copy.3. On the basis of the copy number of β-AS, HMGR and SQS1gene, there were six groups, type B (1+1+1), type A (1+2+1), type H (2+1+1), type I (2+1+2), type F (2+2+1) and type G (2+2+2). Frequency of occurrence of type I was the highest, about74.2%. 4. The content of glycyrrhizin and liquiritin in62samples of cultivated licorice were detected. The differences were very great. The highest content of glycyrrhizin was about2.21%while the lowest was0.07%, and the average was0.55%, while the highest content was31.6times more than the lowest content. The highest content of liquiritin was about3.33%while the lowest was0.59%, and the average was1.51%, while the highest content is5.6times more than the lowest content. It has been found that the glycyrrhizin content and liquiritin content were significantly correlated (r2=0.515).5. The correlation between CNVs of3functional genes and the content of glycyrrhizin and liquiritin was analyzed. In type A the content of liquiritin was the highest (2.21%), and in type H the content of liquiritin was the lowest (0.31%). In type A the content of glycyrrhizin was the highest (3.33%), and in type I the content of glycyrrhizin was the lowest (1.35%). The results of variance analysis showed the differences in content of glycyrrhizin and liquiritin between each group were great. And type A, type B and type F might lead to the accumulation of glycyrrhizin and liquiritin.