DNA barcoding for specific and sensitive detection of Cuminum cyminum adulteration in Bunium persicum

Bunium persicum commonly called as Kala zeera, a very high value herbaceous spice used for medicinal purposes is often adulterated with Cuminum cyminum or Safed zeera, a closely related species. Lack of distinctive morphological features makes the identification of genuine kala zeera from its adulterant difficult, the problem is even exaggerated in case of powdered material.

Genomic DNA was extracted from all the plant materials by using CTAB-SDS method (Möller et al., 1992) with slight modifications. On the basis of reproducibility and high amplification ability, four universal barcoding loci viz. ITS2, rbcL-a, mat K and psbA-trnH and a specific locus Cum were used in the present study. The amplified PCR products were sequenced bidirectionally and assembled to obtain contigs. The sequences thus obtained were aligned using MUSCLE algorithm (Edgar, 2004) and information pertaining to conserved/ variable/ parsimony informative sites, number of transitions, transversions and Indels was obtained after analyzing the sequences.

Among the tested barcoding loci, psbA-trnH has proven to be best barcode in authentication of kala zeera as its amplification and sequencing success was high and it showed the presence of polymorphic sites to detect interspecific variation. This barcode could differentiate between safed zeera and kala zeera in a single reaction, simultaneously.