Note: Excellent photographs available

The next time you pick up a bag of weed killer from The Home Depot, think about this: a chemical company probably spent years of testing and millions of dollars to develop an effective herbicide that is harmful to weeds but safe for you, your children, and your pets. Now a new study of root growth in a tiny weed called Arabidopsis thaliana suggests that genetics could help scientists save valuable time and money in developing better herbicides for the future.

Scientists at the Whitehead Institute for Biomedical Research report that they have cloned and characterized a plant gene called EIR1 (Ethylene Insensitive Root 1) that plays a critical role in the ability of roots to grow toward the earth in response to gravity. The roots of mutant weeds lacking EIR1 lose their ability to respond to gravity and are unable to grow downward into the soil. The findings are reported in the July 15 issue of Genes and Development by first author Dr. Christian Luschnig and his colleagues Ms. Paula Grisafi, Dr. Roberto Gaxiola, and Dr. Gerald R. Fink, director of the Whitehead Institute.

"These findings provide important new insights into age-old mysteries about root growth, and they also may have tremendous implications for the agricultural and pharmaceutical industries," says Dr. Fink. "Currently, most herbicides are developed by trial and error. Compounds first are tested for their ability to kill weeds, and then later tested--often for years--to ensure their safety in animals. Often the most effective ones turn out, in hindsight, to be the compounds that act against genes present only in plants but not in animals. Our findings suggest that one can design new classes of compounds targeted at plant-specific genes like EIR1 such that they would automatically be harmful to plants but safe for humans."

The Fink lab findings have additional implications for the agricultural industry. The genetic makeup o
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Contact: Seema Kumar or Eve Nichols
kumar@wi.mit.edu
(617) 258-5183
Whitehead Institute for Biomedical Research
24-Jul-1998