Genetically engineered potatoes and tobacco plants would now save themselves from four major fungal diseases. Matteo Lorito of the Federico II University of Naples and his colleagues have equipped these plants with a gene which helps make a powerful anti-fungal endochiti-nase. This enzyme digests fungal cell walls and other structures made from the tough biopolymer chitin. The gene itself conies from the fungus Trichoderma harzianum, a parasite which attacks other fungi. It was found that about 10 per cent of the altered plants proved resistant to all four diseases, a trait that was inherited by subsequent genera-tions. According to Lorito, this is the first time a gene of fungal origin has been used successfully to fortify plants against fungal diseases. Earlier, botanists have loaded plants with plant genes which make anti-fungal enzymes, but these provide only weak protection and usually only work against one fungal species. T harzianum overcomes these limi-tations as it makes a powerful chitin-digesting enzyme that is lethal to several strains of fungi (New Scientist, Vol 159, No 2142).