DNA Barcoding of Six Ethnomedicinal and Economically Important Pandanus Parkinson (Pandanaceae) in the Philippines

Abstract

Members of the genus Pandanus are popularly known for their variety of uses, yet there is difficulty identifying its species since discrimination is dependent on its seasonal reproductive parts. DNA barcoding was utilized to establish an ideal locus for the rapid identification and authentication of six Pandanus species in the Philippines. A total of 17 samples representing six species with three endemic taxa were collected and analyzed. Genomic DNA was extracted from leaf samples and was used as a template to generate the DNA barcodes. The BLAST (Basic Local Alignment Search Tool) method, divergence, and NJ (neighbor-joining) analyses were conducted to determine the efficiency of each barcode. The internal transcribed spacer, a nuclear region, was initially assessed in this study; however, plastid markers showed more universality with better amplification and sequencing success rates. In terms of discriminatory power, trnH-psbA revealed a significantly higher interspecific divergence compared to its intraspecific divergence. Phylogenetic analyses using the NJ approach exhibited that trnH-psbA has a better ability to resolve species identity and exclusive lineages than matK. The concatenated gene trnH-psbA + matK was able to generate better species resolution compared to the single barcodes analyzed. In general, rbcL performed poorly in the NJ analysis and has the lowest species discrimination based on its interspecific and intraspecific distances with close values. We provisionally recommend trnH-psbA as the most efficient single candidate barcode for the molecular authentication of Philippine Pandanus species and the combination of trnH-psbA + matK for a better discriminatory ability.