Comparative evaluation of PCR success with universal primers of maturase K (matK) and ribulose-1, 5-bisphosphate carboxylase oxygenase large subunit (rbcL) for barcoding of some arid plants

DNA barcoding is the use of short DNA sequences (~650 bp) of the standard segment of the genome for large scale species identification. The Consortium for the Barcode of Life (CBOL) plant-working group recommended the 2-locus combination of rbcL and matK as the standard plant barcode. These two regions of chloroplast DNA were chosen due to efficient recovery of quality sequences and high levels of species discrimination. We evaluated the success rates of universal primers for amplification of matK and rbcL loci in 26 different plant species (covering 14 families) from Saudi Arabia. Success rate in PCR was higher for rbcL (88%) compared with matK (69%). The universal primers of both matK and rbcL failed to amplify the DNA form 3 plant species belonging to the family Asteraceae (Anthemis deserti, Pulicaria undulate, and Sonchus oleraceus). Two plant species Malva parviflora (Malvaceae) and Salsola imbricate (Chenopodiaceae) indicated different primer binding site (matK) as the amplified PCR products were of lower size than expected for these species. These findings indicate that although currently used universal primers of rbcL and matK are able to amplify many of the plant species they may fail in certain cases due to primer mismatch at the annealing site. Further studies are therefore needed for protocol development, particularly designing of novel universal primers, to extend the barcoding for a broader coverage of plant species.