Developing an efficient DNA barcoding system to differentiate between Lilium species.

Background: Lilium is an important ornamental bulb, possesses medicinal properties, and is also edible. Species within the Lilium genus share very similar morphology and macroscopic characteristics, thus they cannot be easily and clearly distinguished from one another. To date, no efficient species-specific markers have been developed for classifying wild lily species, which poses an issue with further characterizing its medicinal properties.

Results: To develop a simple and reliable identification system for Lilium, 45 representative species from 6 sections were used to develop a DNA barcoding system, which was based on DNA sequence polymorphisms. In this study, we assessed five commonly used DNA barcode candidates (ITS, rbcL, ycf1b, matK and psbA-trnH) and five novel barcode candidates obtained from highly variable chloroplast genomic regions (trnL-trnF, trnS-trnG, trnF-ndhJ, trnP-psaJ-rpI33 and psbB-psbH). We showed that a set of three novel DNA barcodes (ITS + trnP-psaJ-rpI33 + psbB-psbH) could be efficiently used as a genetic marker to distinguish between lily species, as assessed by methods including DNAsp, BI and ML tree, and Pair Wise Group (PWG).

Conclusions: A rapid and reliable DNA barcoding method was developed for all 45 wild Lilium species by using ITS, trnP-psaJ-rpI33, and psbB-psbH as DNA barcoding markers. The method can be used in the classification of wild Lilium species, especially endangered species, and also provides an effective method for selective lily breeding.