Genetic diversity and gentiopicroside content of four Gentiana species in China revealed by ISSR and HPLC methods

G. macrophylla pall, G. dahurica Fisch, G. straminea Maxim, and G. crassicaulis Duthie ex Burk are the major cultivated Gentiana species in Gansu Province, China. The present study has collected 107 wild samples from 19 natural populations and focused on the analysis of their medicinal ingredients, genetic diversity, and relationship, concerning four species’s worrying situation and solutions. High performance liquid chromatography (HPLC) results show that their gentiopicroside contents are 9.75 ± 2.0%, 9.29 ± 2.6%, 8.18 ± 3.2%, and 7.96 ± 3.2% respectively and higher than the criterion standard for Radix Gentianae in Chinese Pharmacopoeia. Low genetic polymorphism was found among these four species with H_E (expected heterozygosity) = 0.147, G_ST (interspecies coefficient of gene differentiation) = 0.3207, and N_m (gene flow) = 1.0593. The unweighted pair group method with arithmetic mean (UPGMA) analysis was performed with POPGENE 1.31 software and Nei’s method but did not clearly differentiate these four species. Their medicinal ingredients did not correlate with the genetic variants (r = ?0.179, P = 0.586). The results indicate that there is no significant difference among four species in regard to the traits of medicinal qualities. All four Gentiana species can be widely cultivated to not only meet the demand of domestic and international market for Chinese traditional medicine, but also help the local conservation of the wild Gentiana resources in China.