FlavrSavr Tomato

The FlavrSavr tomato is a genuinely early and instructive example of genetic engineering aimed not at pest or herbicide resistance, but purely at improving a food product's shelf life and eating quality. It was produced using Agrobacterium-mediated genetic engineering - the same basic Ti-plasmid delivery mechanism covered earlier in the chapter - with the specific goal of retaining the tomato's natural colour and flavour for longer than an ordinary tomato manages. The mechanism is precise: an antisense gene was introduced that interferes with production of polygalacturonase, the enzyme a ripening tomato normally uses to break down pectin in its cell walls, which is what makes a ripe tomato progressively softer over time. By suppressing this one enzyme, the engineered tomato's ripening process is deliberately slowed down, which in turn delays softening and rotting and meaningfu …