Dutch scientists from the Centre for Plant Breeding and Reproduction Research in Wageningen have genetically modified plants so that honey made from their nectar contains medically useful proteins. The work is based on the discovery of a gene promoter that is specific for the nectary, the nectar-producing organ of the plant. By expressing genes under the control of this promoter, specific proteins are produced in the nectar, which is then collected by bees and concentrated into honey. The high concentration of sugars in honey stabilizes the protein structure, making purification relatively easy. "It's very simple to purify proteins from honey," says lead scientist Tineke Creemers, "because the other constituents are just sugar." Creemers has filed for a patent on the method in Europe, the US, Japan, and Korea, and is now looking for commercial collaborators to produce a vaccine against parvovirus in genetically modified petunias. Parvovirus is highly contagious and causes severe vomiting and diarrhea in dogs; Creemers thinks a vaccine could be given directly as honey or honey capsules.