Cloning and sequence analysis of rdna its from plants in genus asarum l / 中草药

ABSTRACT

Objective To clone and analyze ITS sequences of eight Asarum L. medical plants, and to provide evidence for both molecular identification and genetic diversity studies. Methods PCR amplifications were performed with genomic DNA as templates to isolate ITS sequences, and sequence comparisons as well as phylogenetic tree construction were conducted by bioinformatics software. Results Sequencing results indicated that the full ITS sequences of eight Asarum plants ranged from 637 to 646 bp in length, and 5.8 S sequence was highly conserved with identical sequence length and nucleotide composition. However, sequence variations were observed in ITS1 and ITS2, their sequences were 255-257 bp and 226-232 bp in length, respectively. Insertion/deletion and conversion/transition events were occurred frequently in ITS1 and ITS2 sequences, with variable sites of 46 and 30 and parsimony informative sites of 14 and 9, respectively. Results of the phylogenetic analysis indicated that the eight plants grouped to four different clades, which were completely coincide with traditional plant taxonomy. Groups of I-IV corresponded to section Asarum L., Asiasarum L., Longiflora L., and Heterotropa (Nakai) Hara, respectively. Conclusion ITS sequences of eight Asarum plants were rich in informative sites, which could be applied as molecular marker to identify these species.