Preliminary geoherbalism study of Dendrobium officinale food by DNA molecular markers

Dendrobium officinale is commonly used as a traditional valuable Chinese tonic hygienic food. In order to authenticate the quality of hygienic food in the market and geoherbalism in the process of GAP (good agriculture practice), sequences of chloroplast genes (matK and rbcL), the nuclear rDNA ITS region and mitochondria gene nad1 intron2 were used to survey eight populations of D. officinale. No difference was found in sequences of matK, rbcL and nad1 intron2 between populations, except for nine single nucleotide polymorphisms (SNPs) sites in rDNA ITS regions. Two pairs of allele-specific PCR primers based on SNPs were designed to authenticate two genuine populations (GSG and FSC populations). The AS-PCR (allele-specific PCR) fragments of GSG and FSC populations are about 600 and 560 bp, and annealing temperatures are 55–57 and 58–60°C, respectively. Dried “Fengdou” food samples from genuine populations could also be authenticated using two pairs of diagnostic primers. It is demonstrated that methods based on SNPs of rDNA ITS region and AS-PCR are simple, practical and effective for genuine germplasm authentication of D. officinale during the process of GAP and hygienic food quality control.