Analysis of the relationship between ribosomal DNA ITS sequences and active components in Rhodiola plants.

Rhodiola plants are a valuable resource in traditional Chinese medicine. The objective of this study was to evaluate the correlation between ribosomal DNA internal transcribed spacer (ITS) sequences and the three active components in Rhodiola plants. For this, we determined ITS sequence polymorphisms and the concentrations of active components salidroside, tyrosol, and gallic acid in different Rhodiola species from the Tibetan Plateau. In a total of 23 Rhodiola samples, 16 different haplotypes were defined based on their ITS sequences. Analysis of the active components in these same samples revealed that salidroside was not detected in species with haplotypes H4, H5, or H10, tyrosol was not detected with haplotypes H3, H5, H7, H10, H14, or H15, and gallic acid was detected in with all haplotypes except H14 and H15. In addition, the concentrations of salidroside, tyrosol and gallic acid varied between samples with different haplotypes as well as those with the same haplotype, implying that no significant correlation exists between haplotype and salidroside, tyrosol or gallic acid concentrations. However, a statistically significant positive correlation was observed for among these three active components.

Isolation of microsatellite loci for Rhodiola alsia (Crassulaceae), an important ethno-medicinal herb endemic to the Qinghai-Tibetan plateau.

Rhodiola alsia, which has been used widely in traditional Chinese medicine for a considerable time, grows on moist habitats at high altitude near the snow line. Microsatellite loci were developed for R. alsia to investigate its population genetics. In total, 17 polymorphic microsatellites were developed based on ESTs from the Illumina HiSeq(TM) 2000 platform. The microsatellite loci were checked for variability using 80 individuals of R. alsia sampled from four locations on the Qinghai-Tibet Plateau. The total number of alleles per locus ranged from 10 to 20, and the observed heterozygosity ranged from 0.000 to 1.000. The null allele frequency ranged from 0.000 to 0.324. These microsatellites are expected to be helpful in future studies of population genetics in R. alsia and related species.

Determination of genetic variation in Rhodiola crenulata from the Hengduan Mountains Region, China using inter-simple sequence repeats

The plant Rhodiola crenulata is a perennial herbaceous species distributed in the plateau region of southwestern China, especially the Hengduan Mountains region. It has been one of the most important traditional herbal remedies in Tibet for more than one thousand years, but the accelerated and uncontrolled collection of this plant since the 1980s has lead to deforestation. We used inter-simple sequence repeats (ISSR) to assess levels of genetic variation in R. crenulata from nine diverse natural populations in eastern Tibet and northern Yunnan, the first time such a study has been carried out. The 12 primers we used were able to detect 184 polymorphic loc. Analysis of molecular variance (AMOVA) indicated that species level genetic diversity was relatively high (p = 97.83 percent, and Ho = 0.464) and analysis using ShannonÆs index showed that the within and between genetic diversity of R. crenulata are approximately equal. NeiÆs genetic distance and unweighted pair-group method with arithmetic averages (UPGMA) cluster analysis showed that the three populations from Tibet and the six populations from Yunnan form two major clusters. The Yunnan populations from three locations were further divided into three corresponding groups, indicating that genetic differentiation was correlated to geographic distribution. Understanding the genetic structure of R. crenulata provides insight for the conservation and management of this endangered species.