Molecular diversity of 5S-rRNA spacer domain in Fritillaria species revealed by PCR analysis

Beimu (bulbs of Fritillaria) is an important traditional Chinese herbal med icine commonly used as an antitussive and expectorant. There are about 25 s pecies and varieties of Fritillaria that carry the name Beimu on commercial markets. The price for each Beimu may differ by more than 100-fold. Howeve r, the identification of the origin of a particular species on the market i s difficult. Here, a molecular method was used to identify various species of Fritillaria regardless of their geographical origin. The 5S-rRNA coding sequence is highly conserved in higher eukaryotes, but the spacer sequence of the 55-rRNA gene is variable among different species. Total genomic DNA from fresh leaves and bulbs of Fritillaria cirrhoso, F. puqiensis, F. anhui ensis, and F. thunbergii was extracted. The 5S-rRNA spacer region of the ex tracted DNAs was amplified by PCR with a pair of primers located within the conserved coding region. The isolated cDNA clones (similar to 600bp) cover ing the 5S-rRNA spacer domain were sequenced. By aligning the isolated nucl eotide sequences of the four Fritillaria species, sequence diversity was fo und in the spacer region. Furthermore, a unique EcoR I site was used for th e rapid identification of different species of Fritillaria. To our knowledg e, this is the first report on the detection of 5S-rRNA spacer domain seque nces of Fritillaria and their use to identify species.