Scientists have found a way to switch on a plant's genes by letting it soak up some booze. The intoxicating approach, described in next month's Nature Biotechnology, might eventually be used to control production of pest-resistant proteins or to tell plants when to flower.
Ethanol turns on a fungal gene, called AlcR, that tells other genes to make proteins. A team led by Brian Tomsett of the University of Liverpool in the U.K. infected tobacco plants with a virus engineered to carry the AlcR gene. Infected plant cells incorporated the viral DNA, including AlcR, into their own genetic machinery. The researchers rigged it so that the plant cells also incorporated a second gene that AlcR could control--one that produces invertase, a protein poisonous to plants.
The plants grew normally until the researchers added a nip of ethanol--1 part per thousand--to their water. Within 4 days, invertase levels in the plants shot up 15 times, and younger leaves thickened, curled, and yellowed. Adding plain water helped the plants detox--within 8 days, they had started to grow normally again. Tomsett's team also got the genetic switch to work in tomatoes, rapeseed, and the well-researched Arabidopsis thaliana.
The AlcR switch "clearly has commercial potential," says Tomsett. But other plant geneticists aren't ready to pop the champagne yet. "I'm a little bit dubious as to how well it will work in the field," says Christiane Gatz of the University of Göttingen in Germany. For one, she notes, it may be tricky to deliver precise doses of ethanol, which is toxic to plants at high levels.