Study On Improving The Content Of Active Ingredient In Adventitious Roots Of Glycyrrhiza Uralensis

Glycyrrhiza uralensis is a leguminous plant, Glycyrrhiza uralensis is one of the most valuable and most useful medicinal herbs in the world. It has been widely used in treatment of hepatitis, bronchitis and malaria. Morever, the Glycyrrhiza uralensis is a homologous plant food medicine, the glycyrrhizic acid, as its main active components, is a widely used sweeter in food industry and is 250 times sweeter than the sugar. In this study, taking advantage of the established systems for cultivating adventitious roots of Glycyrrhiza uralensis, we elevated the contents of bioactive compounds in the adventitious roots and conducted the studies about the effects of the elicitors.Firstly, the work examined the impact of Bacillus subtilis, Penicillium fellutanum and Escherichia coli on Glycyrrhiza uralensis adventitious roots metabolites. It found that E.coli had the best effects. Furthermore, the work examined the effective component of E.coli, we roughly separated compounds (polysaccharide and proteins) and the result showed that the effect of proteins was better than polysaccharide. In order to find the effective component of protein, we divided the total protein into two fractions (fraction less than 10 kDa and fraction more than 10 kDa). The protein fragment more than 10 kDa significantly increased the metabolites contents in Glycyrrhiza uralensis adventitious roots. The results showed the highest accumulation of total flavonoids (7.59 mg·g-1), glycyrrhizic acid (0.29 mg·g-1), glycyrrhetinic acid (0.27 mg·g-1) and polysaccharide (93.11 mg·g-1) by up to 2.27-fold, 2.64-fold, 2.70-fold and 2.32-fold than control roots, respectively. In order to select more effective elicitors,then this study examined the induction effects of Saccharomyces cerevisiae and Meyerozyma guilliermondii on Glycyrrhiza uralensis adventitious roots metabolites. The highest contents of polysaccharide, glycyrrhizic acid,glycyrrhetinic acid and total flavonoids were obtained in Meyerozyma guilliermondii group,the content of polysaccharide, total flavonoids, glycyrrhizic acid and glycyrrhetinic acid was 2.6, 3.4, 6.3, 4.6-fold higher than the control.We also conduct the studies about the effects of the elicitors on the changes of bioactive compounds, the accumulation of signal molecules, the expression of defensive genes and functional genes in the glycyrrhizic acid biosynthesis pathways, the results indicate that the elicitor can significantly elevate the activities of signal molecules (PLA2,Ca2+, H2O2, ABA, SA, JA, NO and ET), also the expression of defensive genes(PDF1, NOS,PR1, PAL, LOX), the expression functional genes (HMGR, GPS, FPS, SQS, SE, β-AS,CYP88D6 and CYP72A154) in the glycyrrhizic acid biosynthesis pathways, the expression functional genes (C4H and CHI) in the flavonoid biosynthesis pathways and also induce the changes in the bioactive compounds in the adventitious roots of Glycyrrhiza uralensis.