DNA-Barcoding of Some Medicinal Plant Species in Saudi Arabia Using rbcL and matK Genes

In the Kingdom of Saudi Arabia(KSA),thousands of plants are considered to have therapeutic value.The ambiguous use of identification mainly morphological characteristics of many plants has resulted in the adulteration and displacement of plant products which undermine their therapeutic value and weak documentation of plant resources.The aims of this study were therefore to evaluate genetic variability and explore the phylogeographic architecture for Saudi medicinal plant samples using rbcL and matK genes as barcodes for genomic identification.The matK and rbcL sequences collected for these samples were used as key markers for examining the relationship between Saudi medicinal plant species based on genetic diversity.During our study we were successful in identifying and documenting 4 different species(Foeniculum vulgare,Nitraria retusa,Dodonaea viscosa,and Rumex nervosus)located in Saudi Arabia using DNA barcoding technique.A total number of 8 sequences were obtained with a total sequence length of 6176 bp,where it ranged from 617 bp to 878 bp with an aver-age length of 772 bp.The total number of rbcL sequences length is 2801 bp,where it ranges from 617 bp to 807 bp with an average length of 700.2 bp.Out of the 4 plant samples used,only three samples were identified correctly on the species level with an identity percentage higher than 95%using rbcL gene.Additionally,4 matK sequences have been retrieved belong to 4 species.The total number of matK sequences length is 3375 bp,where it ranges from 819 bp to 878 bp with an average length of 843.8 bp.Out of the 4 plant samples used,only two samples were identified correctly on the species level with an identity percentage higher than 98% using matK gene.Both rbcL and matK have been able to identify most of our collected plant samples by genus,and some by species.Using only one DNA-barcoding technique was not reliable for plant identification,where matK and rbcL must be used as a dual DNA-barcoding procedure.

Cloning of fatty acid elongase1 gene and molecular identification of A and C genome in Brassica species

The fatty acid elongase 1 (FAE1) genes of Brassic napus were cloned from two cultivars, i.e. Zhong- shuan No. 9 with low erucic acid content, and Zhongyou 821 with high erucic acid content, using the degenerate PCR primers. The sequence analysis showed that there was no intron within the FAE1 genes. The FAE1 genes from Zhongyou 821 contained a coding sequence of 1521 nucleotides, and those cloned from Zhongshuan No. 9 contained a 1517 bp coding sequence. Alignment of the FAE1 sequences from Brassica rapa, B. oleracea and B. napus detected 31 single nucleotide polymorphic sites (2.03%), which resulted in 7 amino-acid substitutions. Further analysis indicated that 19 SNPs were genome-specific, of which, 95% were synonymous mutations. The nucleotide substitution at po- sition 1217 in the FAE1 genes led to a specific site of restricted cleavage. An AvrII cleavage site was present only in the C genome genes and absent in the A genome FAE1 genes. Digestion profile of the FAE1 sequences from B. rapa, B. oleracea and B. napus produced with AvrII confirmed that the FAE1 genes of B. oleracea origin was recognized and digested, while that of B. rapa origin could not. The results indicated that by AvrII cleavage it was possible to distinguish B. rapa from B. oleracea and be- tween the A and C genome of B. napus. In addition, the FAE1 genes could be used as marker genes to detect the pollen flow of B. napus, thus providing an alternative method for risk assessment of gene flow.