EXPRESSION AND TARGETTING OF ANTIFREEZE PROTEINS IN TRANSGENIC PLANTS

THE QUALITY OF PLANT PRODUCTS WHICH HAVE BEEN FROZEN FOR STORAGE CAN BE COMPROMISED BY THE DAMAGING EFFECTS OF ICE GROWTH WITHIN THE FROZEN TISSUE. A NUMBER OF PROTEINS HAVE BEEN IDENTIFIED WHICH CAN INHIBIT ICE CRYSTAL GROWTH WHEN PRESENT IN VERY LOW CONCENTRATIONS. WE WILL STUDY A GENE FOR ONE OF THESE PROTEINS CLONED INTO PLANTS. IN ADDITION, THE GENE WILL BE MODIFIED SO THAT THE PROTEIN IT CODES FOR IS LARGER AND MORE EASILY DETECTED (BY FUSION TO PROTEIN A FROM STAPHYLOCOCCUS AUREUS), AND IS SECRETED FROM PLANT CELLS (BY THE ATTACHMENT OF SECRETION SIGNAL SEQUENCES). THE ABILITY OF THE TRANSFORMED PLANTS TO EXPRESS AND LOCALISE THE FUSION PROTEINS WILL BE DETERMINED. SIMPLE ASSAYS WHICH MEASURE THE DAMAGE CAUSED BY ICE CRYSTAL GROWTH IN FROZEN PLANT TISSUE WILL BE USED TOASSESS THE ABILITY OF THE PROTEIN TO PROTECT AGAINST THIS DAMAGE. THIS APPROACH OFFERS A NOVEL WAY OF IMPROVING THE QUALITY OF FROZEN FRUITS AND VEGETABLES, AND INCREASING THE RANGE OF FRUITS AND VEGETABLES THAT CAN BE SUCCESSFULLY FROZEN.