Study on the DNA Barcoding of Genus Ligularia Cass. (Asteraceae)

DNA barcoding is a new technology which can identify species rapidly based on short and standardized DNA sequences. Ligularia, a genus of Asteraceae with about 140 species, exhibits high morphological and ecological diversity, which makes the classification and species delimitation difficult, especially in the cases of closely related taxa. In this study, we tested four DNA core barcoding regions (ITS, matK, psbA trnH and rbcL) in 144 samples representing 35 species of Ligularia. The results revealed that the chloroplast regions (matK, psbA trnH and rbcL) have extremely low species identification rate due to low interspecific variation. Conversely, ITS sequence showed higher species identification rate (60%) and could discriminate the species which are difficult to identify. The combination of these four gene fragments did not improve the ability of species discrimination.