A strategy for identifying six species of Sect. Cruciata (Gentiana) in Gansu using DNA barcode sequences / 药学学报

ABSTRACT

Located in the transition zone between the Qinghai-Tibet Plateau and the Loess Plateau, Gansu province is one of the distribution centers of Sect. Cruciata, Gentiana (Gentianaceae) in China. Six species in the section, G. crassicaulis, G. straminea, G. siphonantha, G. officinalis, G. dahurica and G. macrophylla, are native to Gansu. In this paper, samples of 6 species and Halenia elliptica (outgroup) were collected. Nuclear DNA ITS, chloroplast DNA matK, rbcL, rpoC1, trnL (UAA) intron, psbA-trnH, atpB-rbcL, trnS (GCU)-trnG (UCC), rpl20-rps12 and trnL (UAA)-trnF (GAA) were sequenced from these samples. Based on the sequence analyses, high intragenomic polymorphisms were detected in ITS regions of G. crassicaulis, G. straminea, G. siphonantha, G. officinalis and G. dahurica, and they showed incomplete concerted evolution. A methodological study to identifying such close-related species as G. macrophylla, G. officinalis and G. dahurica was carried out based on the special genotypes. The results showed that 7 cp DNA sequence fragments could be used to identify G. crassicaulis, G. straminea and G. siphonantha. With nr ITS genotype II, III and IV of G. dahurica, the species can be distinguished from the close-related G. officinalis using 12 cloned sequences in a sample (with statistical significance). The cp DNA sequences of G. macrophylla were classified into two genotypes, and with genotype II, the species can be distinguished from the close-related G. officinalis and G. dahurica using 6 test samples each (with statistical significance). Furthermore, DNA barcode sequences were determined for all 6 species in Gansu. Also, the studies provide some basic data for analyses of genetic diversity and identification of Gentiana species.