Expedient identification of Magnoliaceae species by DNA barcoding

Magnoliaceae species have high ornamental and medicinal importance, but they are morphologically similar. DNA barcoding has been regarded as a rapid and effective approach for species identification. To determine the efficiency of expedient identification in Magnoliaceae species by DNA barcoding, in this study, we collected 83 samples belonging to 68 species in 10 genera of Magnoliaceae. Candidate DNA regions (i.e., psbA-trnH, matK, rbcL, ITS, ITS2, rpoB, and rpoC1) were amplified and sequenced for the evaluation of their PCR amplification, sequencing efficiency, intra- and inter-specific divergence and barcoding gap by sequence alignment and Kimura 2-Parameter (K2P) distance analysis, and the rate of correct identification was assessed by BLAST analysis. The results showed that psbA-trnH and matK exhibited high performance in efficiency of PCR amplification and the rate of successful sequencing, followed by rbcL. Associated with the analysis of 199 sequences for 96 species in 9 genera of Magnoliaceae retrieved from GenBank, it was discovered that psbA-trnH was highest in inter-specific divergence and rate of correct identification, indicating its efficiency in the identification of Magnoliaceae species. Besides, matK was also easy to amplify and had high rate of correct identification, suggesting its potential to distinguish Magnoliaceae species. This study indicates that DNA barcoding provides an effective technique for the expedient identification of morphologically similar species, and it is a powerful aid to the conventional methods for species identification.