Employing plant DNA barcodes for pomegranate species identification in Al-Baha Region, Saudi Arabia

Abstract

AbstractThe Punica granatum (Pomegranate) tree attracted a lot of interest for its nutritious fruits and therapeutic benefits. Although research on genetic diversity is important to develop breeding programs and implement efficient cultivar improvement, the genetic diversity of pomegranates in Saudi Arabia has not been investigated completely. The two important pomegranate cultivars in Al-Baha region of Saudi Arabia (Bidah-red and Bidah-green), which have recently gained considerable attention due to their unique sweet taste, were studied using DNA barcodes because information about their phylogeny is limited. To reveal the phylogeny of these two cultivars, three DNA barcodes [the internal transcribed spacer 2 (ITS2), ribulose 1,5-biphosphate carboxylase (rbcL), and intergenic spacer region (trnH-psbA)] were used. The ITS2 and psbA-trnH had sufficient polymorphism to allow distinction at the cultivar level, whereas the rbcL region had a uniform sequence; hence, it failed to discriminate among the cultivars. The two cultivars were found to be clustered in the same clade on the phylogenetic tree constructed using the ITS2 and psbA-trnH sequences, suggesting that they are either closely related or have adapted to their locations. As the ITS2 region exhibited higher polymorphism than psbA-trnH, the phylogenetic tree based on ITS2 indicated that Bidah-red and Bidah-green are distinct cultivars. We conclude that ITS2 and psbA-trnH DNA barcodes are capable of authenticating and identifying pomegranate cultivars and can assist in improving pomegranate quality in the future through molecular breeding.