Abstract
Otostegia fruticosa (Forssk.) Schweinf. ex Penz. plant is native to eastern Africa and the Middle East. This study is the first work for barcoding of Otostegia fruticosa subsp. fruticosa in Saudi Arabia with six specific primers (ITS, ITS2, matK, rbcL, TrnH-trnH2 and TrnH-GUG) and evaluating which one of these primers is more efficient than the other to characterize this plant. The results reveled from GenBank showed that there are only two rbcL reference sequences, one ITS sequence and no reference data for ITS2, matK, TrnH-trnH2 and TrnH-GUG sequences are available for Otostegia fruticosa plant. The results of DNA barcoding showed that ITS and matK loci recorded higher values of sequence length and variable sites than those of ITS2 and rbcL. The phylogenetic trees of ITS, TrnH-trnH2 and TrnH-GUG segregated O. fruticosa in a separate clade demonstrating that these loci performed better than ITS2, matK and rbcL for determining the genetic identity of this plant. This study contribute to supply molecular data about O. fruticosa based on DNA barcoding in Gene Banks, can be used for taxonomical studies of O. fruticosa and detect its relationship with other Lamiaceae species and determine the position of the Otostegia fruticosa collected from Saudi Arabia in the new generic classification.