| Licorice, a perennial herbaceous plant, is one of the most generally used herbal medicine in the world, consisting of the roots, rhizomes, and stolons of Glycyrrhiza uralensis Fisher or Glycyrrhiza glabra Linne or Glycyrrhiza inflala Bat. (Fam. Leguminosae), which is mainly distributed in arid and semi-arid areas in Asia. With the increase of licorice usage, wild licorice resources become increasingly scarce, cultivated licorice has gradually become the mainstream of medicine market products. Many studies have shown, however, the quality of cultivated licorice is far less than that of wild licorice. And how to improve the medicinal component content in cultivated licorice has been the current focus of traditional Chinese Medicine resources. Previous studies have found that the content of glycyrrhizin in the adventitious roots from wild licorice for the asexual reproduction is much higher than that in the real roots developing from the seed. So, presumably, wild licorice has characteristic of rapid accumulation of medicinal components.Based on the results, this paper chose the wild licorice underground stolons and wild licorice seeds collected from the wild licorice in licorice main areas for materials, and decorated wild rhizome asexual and seed sexual reproduction cultivation comparing experiment according to randomized block set. And the same cultivation management measures were made for 2 years. And then the adventitious roots from wild licorice for the asexual reproduction and the real roots developing from the seed were dug respectively. On one hand, based on HPLC and UV analysis, the two analytical materials were analyzed by medicinal component quantitatively (difference comparison of the contents of glycyrrhizin, liquiritin, isoliquiritin, liquiritigenin and isoliquiritigenin and the content of total flavonoids) and medicinal component qualitatively (HPLC fingerprint analysis), comparing systematically medicinal component accumulation speed difference of wild licorice and cultivated licorice. From the results of the chemical analysis, on the other hand, the individuals who differenced significantly were extracted, and the licorice root suppression subtractive SSH cDNA library was built based on SSH technology. And further by cloning and sequencing, and bio informatics analysis, the ESTs associated with the medicinal component’s accumulate at a high-speed in wild licorice were screened. Specific results are as follows:(1) Before sampling and analysis of licorice samples, in order to ensure a reasonable sampling, and that the test results are accurate and reliable, it is necessary to analyze the distribution patterns of the contents of five activate components in wild stolon and cultivated taproot of G. uralensis. By comparing the distribution patterns of the contents of five activate components in the same wild stolon and cultivated taproot, it was indicated that the contents of glycyrrhizin, liquiritin, isoliquiritin, liquiritigenin and isoliquiritigenin in new part at the end of the stolon was lower. However, different from that of wild stolon, in cultivated taproot, the contents of glycyrrhizin, liquiritin and isoliquiritin were higher in the finer parts of the taproot, and the contents of liquiritigenin and isoliquiritigenin were higher in the thick part of the taproot.(2) Studied accumulation speed difference of the content of medicinal component under two kinds of licorice breeding mode, the result showed that in addition to the contents of liquiritigenin and isoliquiritigenin, the other three kinds of medicinal component and content of total flavonoids were higher in adventitious roots from wild licorice for the asexual reproduction than that in the real roots developing from the seed. And by SPSS analysis, in addition to isoliquiritigenin, there were significant differences between the two groups of the other medicinal component and total flavonoids. And based on HPLC fingerprint, the medicinal components between two kinds of licorice differenced significantly, similarity of 0.647. Therefore, there was significant differences between the main medicinal component contents in wild adventitious roots and in cultivated real roots, and wild licorice had the function of rapid accumulation of medicinal components.(3) This study successfully constructed the licorice root forward suppression subtractive library, and sequenced analysis 621 ESTs were clustered together to get 168 unigenes, including 55 contigs and 113 singletons. And the unigenes sequence length range is 78-1017 bp, with an average length of 278bp. Using NCBI/Blastx tools and non-redundant protein database (nr) to analyze and compare the homo logy (E-value< 10-5), there were 40 unigenes got a good match. And these sequences were then handled respectively by swissport function annotation, COG function classification, GO annotation and KEGG pathways analysis. According to above results, speculated that the underlying causes that wild licorice adventitious root was different from the cultivated real root on the accumulation speed of medicinal components may be related to the expression of these genes:glutathione S-transferase (GST), chalcone synthase (CHS), proline rich protein, S-adenosine methylthio acid synthase, phenylalanine ammonia lyase (PAL), polyketide reductase (GGPKR2), 1,3-β-D-glucosidase Portugal, poly ubiquitin and heat shock protein HSP70.The results of this study provided molecular evidence for medicinal component accumulation speed differences between wild and cultivated G. uralensis, as well as lay the molecular foundation for further revealing the molecular mechanism of gene expression of wild licorice medicinal components rapid accumulation.
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