ABSTRACT
italic>Gentiana crassicaulis Duthie ex Burk. is one of the plant sources of Gentianae Macrophyllae Radix (QinJiao). Gentiana tibetica King ex Hook. f. and Gentiana robusta King ex Hook. f. are relative species of G. crassicaulis. Due to the large intraspecific morphological variation, G. crassicaulis showed high morphological similarity with G. tibetica and G. robusta. And the distribution area of the three species overlaps to some extent, which makes it difficult to identify them. On the basis of morphological identification, the method of molecular identification of the three species was constructed in this study based on chloroplast genomes. The chloroplast genome of Gentiana tibetica is 148 765bp long, with LSC, SSC and IR 81 163 bp, 17 070 bp and 25 266 bp, respectively. The structure of the three is consistent. The chloroplast genome sequences of G. tibetica and G. crassicaulis are highly similar, and the number of variable sites is 9 (149 267 bp in total). Diagnostic SNP that could effectively identify the three species was screened and verified, and a dual-peak SNP detection method was established for the effective identification of each species and mixed samples. Our study provides basic data for the molecular identification of G. crassicaulis and its related species, and the arrangement of related Tibetan medicine.
ABSTRACT
The key factors for producing the best quality Chinese herbal medicines are high-quality germplasm, suitable cultivation area and the proper processing methods for herbal raw materials. Gentiana crassicaulis in Gentiana (Sect. Cruciata), Gentianaceae is one of the original plants of the Chinese herb Qinjiao (Gentianae Macrophyllae Radix), and its type specimen was collected in Lijiang, Yunnan. There is a long planting history of the herb in this area. In this study a sampling plot was designated in these traditional planting areas. G. crassicaulis was planted and herbal raw materials were harvested from the plot. The raw materials were prepared locally and at a pharmaceutical factory in Shanghai using processing methods such as "sweating" or "no sweating", "slicing" or "no slicing" (whole root), and "stoving" or "no stoving" (air drying). The quality of all processed samples was evaluated. In addition, molecular markers were determined for identifying cultivated and wild samples from Lijiang, Yunnan. The results are as follows: ① Samples from the sampling plot and the field are taxonomically identified as Gentiana crassicaulis. ② A total of 270 sequences of trnC-GCA-petN, atpB-rbcL, psbN, ndhB-rps7 and ycf1 were obtained, and three genotypes were determined from the cultivated samples; the type III was shared by both cultivated and wild plants. Based on the molecular markers, a DNA barcoding method to identify cultivated and wild samples of G. crassicaulis from Lijiang, Yunnan was established. ③ Total content of loganic acid and gentiopicroside in all samples was ≥ 2.5%, and above the Chinese Pharmacopoeia (2020) limit. ④ In HPLC fingerprinting, 9 common peaks were assigned and similarity between all samples was > 0.999; and ⑤ In a PCA score plot all slice samples were clustered, while whole root samples were scattered. Therefore, our studies could provide basic data for optimizing the processing method, producing best quality Gentianae Macrophyllae Radix, and evaluating the quality of different ecotype varieties and the multiple origin of herbal medicines.
ABSTRACT
italic>Gentiana crassicaulis Duthie ex Burk. in Gentiana (Sect. Cruciata), Gentianaceae, is one of the original plants of both Gentianae Macrophyllae Radix and Tibetan herb Jie-Ji Na-Bao, which contain such bioactive iridoids as gentiopicroside, loganic acid and others. In this study, based on previous work, the transcriptome of G. crassicaulis was sequenced and analyzed to construct transcriptome databases of roots, stems, leaves and flowers. qRT-PCR verification was conducted for parts of unigenes that may be key enzymes in the pathway of iridoid biosynthesis. The results are as follows: ① a total of 159 534 unigenes were obtained, with an average length of 679 bp. According to the functional classification of GO, unigenes can be divided into 3 categories with 67 branches. The unigenes were aligned in the KOG database and were classified into 25 categories according to function. ② In the KEGG database, 215 unigenes were implicated in 20 standard secondary metabolism pathways. The analysis shows that 305 unigenes encoded 28 key enzymes in the pathway of iridoid biosynthesis, and their expression in different organs is different; and ③ qRT-PCR was approximately consistent with RNA-Seq results. The 7 annotated unigenes identified in this study, HMGS, DXS, MCS, GPPS, G10H, 7-DLNGT and STR, all had higher relative expression levels in the above-ground parts (stem, leaf and flower) than in the underground part (root). Iridoids are common active and index components of such traditional Chinese medicines as Qinjiao, Longdan, Dangyao, and Qingyedan, among others. Therefore, this work provides basic scientific data for further development including obtaining active components or intermediates through biotechnology, exploring the accumulation of effective components, evaluating the quality of different ecotype varieties, and identifying authentic biosynthesis pathways of medicinal materials.
ABSTRACT
Jieji Nabao is a common Tibetan herb. According to our ethnobotanical studies, one of its original plants is identified as Gentiana crassicaulis Duthie ex Burk. (Gentianaceae). Endemic to the Qinghai-Tibet Plateau, this medicinal alpine plant is a threatened species. In this study, 163 individuals from 20 populations of G. crassicaulis were collected throughout its geographical range and amplified fragment length polymorphism (AFLP) was used to investigate genetic variation in this species. A cluster analysis was performed on the AFLP data with Halenia elliptica and Gentiana straminea as the outgroups. From 64 pairs of AFLP primer combinations, 12 pairs were selected for amplification and a total of 315 bands were amplified, of which 254 bands were polymorphic, accounting for 80.63%. High genetic differentiation was detected between populations (87%), and low within populations (13%). The UPGMA (unweighted pair-group method with arithmetic means) tree was topologically consistent with the traditional taxonomic treatments at the species level, and the populations of G. crassicaulis were divided into two branches: one from Yunnan and Guizhou, the other from Tibet, Qinghai, Sichuan and Gansu. PCA analysis and the Mantel test showed that there was a positive correlation between genetic distance and geographical distance. In addition, combined with SSR and SNP markers within cpDNA, the genetic differentiation within the Sichuan population S1 was validated.