Accumulation of human EGF in nectar of transformed plants of Nicotiana langsdorffii x N. sanderae and transfer to honey by bees.

Honey has been used successfully in wound healing for thousands of years. The peptide hormone human epidermal growth factor (hEGF) is also known to have a beneficial effect in various wound healing processes via mechanisms that differ from those for honey. In this study, we show that hEGF can be incorporated into honey via nectar. Plants of Nicotiana langsdorffii x N. sanderae were transformed with the gene for hEGF, equipped with a nectary-targeted promoter and a signal sequence for secretion to nectar. These plants accumulated hEGF in the nectar. The maximum hEGF concentration recorded with ELISA in these plants is 2.5 ng·ml⁻¹. There is a significant linear relationship (P<0.001) between hEGF concentration and induction of hEGF-receptor phosphorylation. Since the flower morphology of these plants did not allow production of honey from their nectar, we used feeding solutions, spiked with synthetic hEGF, to study transfer of this peptide into honey through bee activity. Transfer of hEGF from a feeding solution to honey by bees occurred with retention of the hEGF concentration and the capacity to induce hEGF-receptor phosphorylation. These observations indicate that plants can function as a production platform for honey containing biologically active peptides, which may enhance wound healing and other biological processes.