Studies on authentication of true source of honey using pollen DNA barcoding
Praghadeesh Manivanan, Srinivasan Madapuji Rajagopalan and Mohankumar Subbarayalu
Plant pollen DNA comprising unique barcode signatures– serve as a highly resilient biomarker to establish its true biological origin. Over a decade, DNA barcoding of plants has evolved as an effective tool to identify its origin down to species level that promptedits practical applications in various fields of applied biology. Premium unifloral honey, due to its economic value as a medicinal product is vulnerable to intentional mislabelling and adulteration to fetch higher price. Melissopalynological and physiochemical based approaches to ascertain the true source of honey is not yet available on commercial scale. DNA barcoding of pollen trapped in honey can be effectively used to identify the true source of honey with high feasibility across labs at cheaper price. The current study was carried out to standardise an efficient pollen DNA isolation protocol and to assess the efficiency of two barcode (rbcL and matK gene) combinations in identifying the botanical origin of pollen and to ascertain its true source. Six honey samples with diverse characteristics were used in the study. Pollen DNA isolated using modified CTAB solution resulted in quantitatively appreciable yield with less Polymerase Chain Reaction inhibitors. Further, the two barcode combinations were found to be effective in identifying the true botanical origin of honey samples with 96 to 98 percent confidence. We report here a unique methodology to authenticate true honey source by harnessing the power of both efficient DNA isolation strategy and pollen DNA barcoding.