FUNGAL AND BACTERIAL DISEASE RESISTANCE IN TRANSGENIC PLANTS EXPRESSING HUMAN LYSOZYME

The human lysozyme gene, which is assembled by the stepwise ligation o f chemically synthesized oligonucleotides, was introduced into tobacco (Nicotiana tabacum cv 'SR1') by the Agrobacterium-mediated method. Th e introduced human lysozyme gene was highly expressed under the contro l of the cauliflower mosaic virus 35S promoter, and the gene product a ccumulated in the transgenic tobacco plants. The transgenic tobacco pl ants showed enhanced resistance against the fungus Erysiphe cichoracea rum - both conidia formation and mycelial growth were reduced, and the size of the colony was diminished. Microscopic observation revealed t hat the transgenic tobacco plants carried the resistant phenotype, ana logous to that of the resistant cultivar 'Kokubu' which had been selec ted by conventional breeding. Growth of the phytopathogenic bacterium Pseudomonas syringae pv. tabaci was also strongly retarded in the tran sgenic tobacco, and the chlorotic halo of the disease symptom was redu ced to 17% of that observed in the wild-type tobacco. Thus, the introd uction of a human lysozyme gene is an effective approach to crops agai nst both fungal and bacterial diseases.