ABSTRACT
OBJECTIVE: To study and exploit Chinese medicine Astragali Radix, the molecular markers that relates to the phenotypic traits on medicinal components of Astragali Radix and would be detected. METHODS: The genetic diversity of 43 Astragali Radix samples was analyzed with ISSR molecular marker technique and then the population genetic structure was studied through 13 selected markers. The association analysis between ISSR markers and 4 phenotypic traits of medicinal components were performed with GLM (general linear model) programs in Tassel 2.1. Certain genetic diversity was discovered among the 43 Astragali Radix samples. RESULTS: The genetic distance varied between 0.050 6 and 0.743 8, with an average of 0.274 1. Moreover, the cultivated Astragali Radix from Ningxia and Gansu province closely related to the wild Astragali Radix collected from Liupanshan town in Ningxia. On the other hand, No. 340 had the farthest relationship with other Astragali Radix. The content of polysaccharide, total saponins, total flavonoids, and Astragaloside IV ranged between 7.693-27.840 mg•g-1, 7.167-17.579 mg•g-1, 2.212-6.164 mg•g-1 and 6.070-107.920 μg•g-1, respectively. Meanwhile, linear regression analysis indicated that there was a significant positive correlation between the content of the total saponins and that of flavonoids (r=0.650 5,P=2.3×10-6<0.01), while the content of astragaloside had no significant correlation with that of polysaccharide, total saponins and total flavonoids. The population genetic structural analysis showed that the 43 samples were divided into 4 subgroups. There were total of 34 locus in 13 ISSR markers significantly associated (P<0.01) with the content of polysaccharide,total saponins, flavonoids and astragaloside , and the rate of explanation on the phenotype of related marker ranged from 8.14% to 51.39%. Among the locus, 15 were related with astragaloside content at interpretation rates above 30%, 1 with polysaccharide content an interpretation rate reached as high as 51.39% with high threshold (P<1×10-5). CONCLUSION: These results would provide supporting evidence for identification and protection of germplasm resources as well as molecular marker-assisted breeding.
ABSTRACT
Establishing the genetic transformation system of medicinal plant is important to study their functional genes. Based on the established regeneration system of Sophra alopecuroides, 6 factors of genetic transformation were optimized, that was the concentration of Agrobacterium tumefaciens, the infection time, the co-cultivation time of agrobacterium tumefaciensand S.alopecuroides callus, the preculture time of S.alopecuroides callus, the adding method ofacetosyringone (AS) and the concentration of AS, respectively. The results showed that a maximum genetic transformation efficiency of 83.33% was achieved with 15d-precultured of S.alopecuroides callus, which was infected by A600=0.9 A. tumefaciens for 15 minutes and then co-cultivated for 48 hours with 200 μmol•L-1AS. The promoter sequence (1 260 bp) of upstream SaLDC was cloned from S.alopecuroides genomic DNA (gene bank accession number: KY038928). The deletion fragment of SaLDC promoter with different length (310,594,765,924,1 260 bp) were ligated with the GUS reporter gene to form five plant expression vectors named P310,P594,P765,P924,P1260, which were then transferred into S.alopecuroides callus. The GUS transient expression showed that all 5 different deletion fragment of SaLDC promoter can drive the GUS gene expression in S. alopecuroides callus. The SaLDC promoter we cloned has high promoter activity, and they may facilitate its function analysis in the future.