Developments to Watch
A GENETIC SWITCH THAT TURNS PLANT GROWTH ON OR OFF
Farmers use chemical growth regulators to thin their fruit trees, speed up ripening, and then delay the fruits' falling. Of course, plants have their own ways of doing this--with growth hormones. If scientists could figure out how to switch Mother Nature's hormones on and off, environmentally damaging chemicals could take a backseat.
Michigan State University scientists have isolated from corn the first gene controlling the action of a plant growth hormone. The gene regulates the binding of indole-3-acetic acid, or IAA, to a sugar molecule. This binding prevents the IAA hormone from promoting growth. Isolating and altering equivalent genes from other crops could produce plants whose fruit follows a tailored growth pattern when triggered by, say, a specific temperature. MSU biochemist Robert S. Bandurski estimates that such genetic methods could be available in two years. "As we move toward a greener world, we'd like to control growth genetically rather than chemically," he says.EDITED BY OTIS PORT