| Astragalus is an important medicinal plant originated from the dried root of Mongolia medicinal herb Astragalus membranaceus and Astragalus membranaceus.The polysaccharides,saponins and flavonoids are the main active ingredients in Astragalus,which can enhance the immune function of the body,protect the liver,diuresis and resist aging.The medicinal value of Astragalus membranaceus is very high.In this paper,the differences of total saponins?Astragaloside IV and total flavonoids derived from 47 different Astragalus germplasm resources were studied.Using ITS and ISSR molecular markers to analyze the genetic diversity of different germplasm resources,and to carry out correlation analysis between the active ingredients and molecular markers of Astragalus membranaceus,The purpose of this study was to understand the genetic background of Astragalus germplasm resources,The relationship between total saponins,total flavonoids,astragaloside and ISSR molecular markers in Astragalus membranaceus was initially revealed and provide theoretical basis for the introduction,selection,and rational use of high quality provenances of Astragalus germplasm resources.The results of the study were as follows:(1)The content of total saponins,Astragaloside IV and total flavonoids from different Astragalus germplasm resources was difference,the coefficient of variation was 16.71%?49.23%and 19.64%,respectively.The range of total saponins?Astragaloside IV and total flavonoids in Astragalus membranaceus were 7.1670?17.5790 mg/g?6.0700?107.9200 ?g/g and 2.2120?6.1639 mg/g,respectively.The contents of total saponins were higher than those of total flavonoids,and there was a very significant positive correlation between the them.There was no correlation between the content of Astragaloside IV and content of total saponins,total flavones.(2)A total of 3 type ITS sequences which the fragment size ranged from 611?618bp were detected in 47 Astragalus germplasm resources,and the similarity of sequence was 99.67%.There were 42 SNP locus were found in these 3 sequences inclueding insertion and deletion of bases.The distributionof 42 SNP locus in ITS1,5.8S section and ITS2 ws 24,1 and 17,respectively.The sequence type of germplasm resources 340 is the largest difference with other sequences.(3)The totle of 222 polymorphic loci were detected in 780 individuals of 39 Astragalus germplasm resources by 13 ISSR primers,and the average polymorphic percentages of each primer were 100%.The average Nei 'sgenetic diversity index(H)and Shannon information index(I)in 39 germplasm resources were 0.1852 and 0.2891,respectively.The genetic diversity index(H)and Shannon information index(I)of species were 0.2419 and 0.3843,respectively.The genetic diversity of species was higher than germplasm resources.The genetic differentiation coefficient of 39 Astragalus germplasm resources was 0.2235.the average gene flow was 1.9591,which indicated that there was a certain gene exchange between the various germplasm resources of Astragalus,and 39 germplasm resources were divided into 4 categories by cluster analysis.(4)The totle of 162 polymorphic loc wsa detectedi in the mixed DNA samples of 47 germplasm resources by 13 ISSR primers,of which 155 were polymorphic.The average percentage of polymorphic loci was 95.71%,the average number in loci of each primer was 12.46,and the polymorphic loci was 11.92.The average of Nei's genetic diversity index(H)and Shannon information index(1)were 0.2327and0.3728 47 germplasm resources were divided into 4 categories by cluster analysis.(5)61 loci of 13 ISSR primers were associated with total saponins and total flavonoids,and primer 57 could be associated with the most sites,with a total of 11 loci.There were 24 loci associated with total saponin,the contribution rate was ranged from 5.05%-12.57%.There were 23 loci associated withAstragaloside ?,the contribution rate was ranged from 9.98%?30.24%.There were 35 loci associated with total flavonoids,the contribution rate was ranged from 4.64%?11.11%.There are 16 lociassociated with the contents of total saponins and total flavonoids.There are 5 loci associated withthe contents ofAstragaloside ? and total flavonoids,... |
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