TITLE:
Emergence of Plastidial Intergenic Spacers as Suitable DNA Barcodes for Arid Medicinal Plant Rhazya stricta
AUTHORS:
Samia A. Khan, Mohammed N. Baeshen, Hassan A. Ramadan, Nabih A. Baeshen
KEYWORDS:
Rhazya Stricta, Medicinal Plant, DNA Barcoding, matK, rbcl, rpoB, rpoC1, atpF-atpH, psbK-psbI, Two-Dimensional DNA Barcode, QR Code
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.8 No.8,
July
3,
2017
ABSTRACT: The
desert plant Rhazya stricta has
anticancer and antimicrobial properties, and is widely used in indigenous
medicines of Saudi Arabia. However, the therapeutic benefits rely on an
accurate identification of this species. The authenticity of R. stricta and other medicinal plants and herbs procured from
local markets can be questionable due to a lack of clear phenotypic traits. DNA
barcoding is an emerging technology for rapid and accurate species
identification. In this study, six candidate chloroplastid barcodes were
investigated for the authentication of R. stricta. We compared the DNA sequences from fifty locally collected and five
market samples of R. stricta with database sequences of R. stricta and seven closely related species. We found that the coding regions matK, rbcL, rpoB, and rpoC1 were highly similar among the taxa. By contrast, the intergenic spacers psbK-psbI and atpF-atpH were variable loci distinct for the medicinal plant R. stricta. psbK-psbI clearly discriminated R. stricta samples as an efficient single locus marker, whereas a
two-locus marker combination comprising psbK-psbI + atpF-atpH was
also promising according to results from the Basic Local Alignment Search Tool
and a maximum likelihood gene tree generated using PHyML. Two-dimensional DNA
barcodes (i.e., QR codes) for the psbK-psbI and psbK-psbI + atpF-atpH regions were created for the validation of fresh or dried R. stricta samples.