Polyphenolics, antioxidant characterization and DNA barcoding of Kala zeera [Bunium persicum (Boiss.) Fedtsch] through multiple barcode analysis to unravel best barcode combination

BACKGROUND: Kala zeera [Bunium persicum (Boiss.) Fedtsch] is one of the important spice crops of North Western Himalayas with lot of medicinal and culinary values. In spite of having great importance, this crop is under the threat of extinction due to loss of habitat and lack of awareness. The limited availability of the seeds has ultimately increased the economic value of this spice. The upmarket of Kala zeera leads to its adulteration with other black seeds and cumin seeds. The present investigation was undertaken to evaluate polyphenolics and antioxidant properties of Kala zeera genotypes collected from North Western Himalayas and to develop DNA barcodes that can ensure their purity and can also guide in conservation of selected Kala zeera germplasm lines. METHODS AND RESULTS: Various locations of North Western Himalayas were explored for collecting 31 diverse germplasm lines of Kala zeera. The collected germplasm was maintained at our experimental stations during 2019–2020 and 2020–2021. These genotypes were evaluated for different seed traits and the methanolic extract from Kala zeera seeds was examined for total phenolic content, total flavonoid content, antioxidant activities by DPPH and FRAP. The results revealed significant variation in seed traits, polyphenolic content and antioxidant properties. 100 seed weight ranged from 0.05 to 0.35 g, TPC ranged from 7.5 to 22.56 mg/g, TFC ranged from 0.58 to 4.15 mg/g, antioxidant properties DPPH ranged from 168 to 624.4 μg/ml and FRAP ranged from 0.72 to 6.91 mg/g. Further, three different barcodes (ITS, rbcL and psbA-trnH) were used to reveal the authenticity of selected Kala zeera. MEGA 5 software was used for clustering and the barcodes did clustering based on geographical distribution of Kala zeera germplasm. CONCLUSION: Based on molecular barcoding, best barcode combination was identified that may discriminate the Kala zeera germplasm vis-a-vis can authenticate their purity. Moreover, the identified DNA barcodes will have significant role in studying the evolutionary biology of Bunium species and will be important for designing a strategy to conserve the selected Kala zeera germplasm lines. The identified genotypes with high phenolic content and antioxidant activity can further be utilized in Kala zeera breeding programmes.