UF Breakthrough Turns Herbicide Into Fertilizer
GAINESVILLE — One plant’s poison may be another plant’s fertilizer. University of Florida researchers reached that conclusion about a new lettuce variety that they genetically engineered.
A gene that researchers transplanted into the lettuce digests the herbicide glyphosate, releasing the fertilizer phosphorous.
“We were surprised that the lettuce plants we sprayed with the herbicide actually did better,” says Robert Ferl, a professor of horticultural sciences with the university’s Institute of Food and Agricultural Sciences.
University researchers developed the new lettuce — and they’re working on other new varieties that will ward off insects — to help keep the “nation’s winter salad bowl,” a rich farming area bordering the Everglades, from wilting.
By eliminating manual hoeing, the new lettuce will save up to $500 per acre and help Florida growers who are struggling to compete with lettuce cultivated in Western states, where soil is better suited to herbicides that kill weeds before they sprout.
“We can apply glyphosate when the weeds are just getting started,” Ferl said. “The weeds die, but the lettuce thrives.”
Ferl and his colleagues transplanted two genes into the plant. One gene digests glyphosate, and the other prevents the lettuce from withering under the herbicide.
“Glyphosate is very compatible with the environment,” Ferl says. “It breaks down quickly and has little effect on people and animals.”
The new lettuce should increase yields by eliminating the up to 20 percent crop loss that results from hoeing. “That will benefit consumers at the checkout counter,” said Russell Nagata, an associate professor of horticultural sciences at a UF research center in Belle Glade.
It’s too soon to determine the potential for engineering other plants in which the herbicide, marketed under the trade name Roundup, will do double duty — enriching the plants while killing surrounding weeds.
Besides developing the new “Roundup Ready” lettuce, UF researchers also are working on lettuce that will ward off a tiny insect that destroys thousands of acres of crops. Their goal is to develop hybrids that will be less appetizing to the leafminer, an insect named for its burrowing of plants.
“Leafminers love the variety of romaine lettuce that most Florida growers produce, but they dislike three other varieties we tested,” Nagata said. “When we provided honey near the test plants, the insects ate the plants and did well. This makes us suspect that the honey made up for nutrition that the insects get from the popular variety.”
Why not switch immediately to other varieties of romaine lettuce?
Alas, the alternative varieties have drawbacks. “Some don’t look right to consumers, and others are susceptible to disease,” Nagata said.
Researchers plan to cross-pollinate romaine lettuce varieties to develop a plant that will resist pests yet make a great Caesar salad.
“Although we’re studying only varieties grown in Florida, our research could be applied to similar problems elsewhere,” Nagata said. “Developing a super plant could benefit everyone.”
- Chris Eversole