Regulation On The Flavonoids Accumulation And Related Gene Expression By Moderate Drought Stress In Glycyrrhiza Uralensis

Glycyrrhiza uralensis Fisch is a herbaceous of perennial legume, the roots and rhizomes of which named licorice are used as medicine, with Spleen Qi, detoxification, expectorant cough, reconcile the various drugs and other effects, and effective medicament for Stomach weakness, malaise, fatigue, palpitations, shortness of breath, cough and sputum. In ecent years, with the pharmacological effects of licorice depth, indicating that flavonoids are very effective active ingredient in G. uralensis. The flavonoids has pharmacological effects of antioxidant, anti-tumor, anti-inflammatory, anti-allergic, anti-AIDS virus, etc. G. uralensis and its extracts are used widely in making food, medicine and cosmetic, which demand continues to rise, but there is considerable difference between cultivated and wild licorice, and no real sense of cultivars in production. It limits the development of licorice industry. Many studies have shown that moderate drought stress can promote the active ingredient accumulation of licorice and improve the quality of G. uralensis. Previous experiments have used transcriptome sequencing technology to analyze regulation of G. uralensis roots transcriptomics by moderate drought stress, and found some genes of flavoinoid biosynthesis. On the basis of further study on regulation of effective content accumulation and gene expression on biosynthesis of flavionoid, and preliminarily revals molecular mechanism of accumulated glycyrrhiza flavonoids by moderate drought stress.In this experiment, six-month-old cultivation of G. uralensis as experimental materials sampled by different times of drought stress, measured and analyzed by were HPLC to definite dynamic changes of the content of each component. The results showed that flavonoids and terpenoids are the main effective active ingredient of G. uralensis. G. uralensis is the main component of licorice flavonoids, which content change and accumulation trendcontent have certain correlation with the accumulation of flavonoids. Content of G. uralensis under Stress 50 d is not significantly increased, while stress 70 d increased rapidly, showing prolonged stress can contribute to the cumulative time of glycyrrhiza flavonoids. The content of glycyrrhizic acid is showing an increasing trend after the first reduction, which is not consistent with flavonoids growth trend. The content of the active ingredient of G. uralensis under stress 70 d in the highest, which is relacted with G. uralensis traditionally grown in the more arid areas. Promoting the active ingredient of glycyrrhizic acid and improve the quality of G. uralensis itself herbs under longer-time stress.This research moderate drought stress(field capacity: 40-45%) of G. uralensis as materials, using Solexa Genome-wide expression profiling technology, establish differences in gene transcription G. uralensis expression profiles, and isolution of differentially expressed under drought conditions genes. Screening transcriptome sequencing results from drought stress stress-related genes on the biosynthesis of flavonoids active ingredients, using RT-PCR to detect gene G. uralensis flavonoids, including isoflavones 2’-hydroxylase(I2’H), isoflavonoid glucosyltransferase(IFG), chalcone isomerase(CHI), flavonoids synthase 2(FS2) differentially expressed. Moderate drought stress makes overexpression of CHI, and reached highest expression of CHI under stress 50d; the appropriate time of drought stress can promote FS2 expression, and longer-time period of drought stress will inhibit the expression of FS2 gene. Where appropriate drought stress, high expression of IFG transfer time and drought stress has no direct impact on the IFG. According to the results of the above semi-quantitative RT-PCR, moderate drought stress conditions, the flavonoid biosynthetic pathway leading to upregulation of key genes, making the cumulative licorice flavonoids.In GuI2’H c DNA sequences for the study, successfully cloned the gene, and put a basis forlater experiment. To analyse the structure, function and molecular evolution of an isoflavone 2’-hydroxylase cDNA sequence(Gu I2’H) and encoded protein by bioinformatics software and network tools in Glycyrrhiza uralensis. The cDNA full sequence of GuI2’H was 2425 bp with an open reading frame of 1521 bp, encoding a polypeptide of 475 amino acid residues. The protein GuI2’H encoded belongs to the endoplasmic reticulum transmembrane protein, which has a high sequence identity with I2’H of other species, and closely related with I2’H in Astragalus mongholicus, Glycine max and other Leguminosae plants, which belong to the cytochrome P450 family.