Friday, May 20, 2022

U professor looks for natural alternative to combat insects

January 31, 2001
Gregg Howe, assistant professor of biochemistry and molecular biology, is researching plants —

MSU Professor Gregg Howe knows there’s a lot more going on in plants than meets the eye.

Howe, an assistant professor of biochemistry and molecular biology, is researching a project to use plants’ own defense mechanisms as pesticides.

“We study plant defense systems,” Howe said. “Our goal is to discover natural pesticides that are effective against herbivores, especially insects - they are the major threat to plants.”

Fifteen percent of all foliage is consumed by herbivores, he said.

“This loss is not a big deal on campus, but for a farmer it is a big deal,” Howe said. “Billions of dollars are lost every year as a result of plant predators.”

Traditionally, farmers spray chemical pesticides to protect their crops and it has been a very effective way to control pests, he said. However, due to environmental impacts, the government has banned the use of some of the more potent pesticides. Additionally, insects have a remarkable ability to develop resistance to these pesticides, Howe said.

“Our aim is to understand plants’ natural defense mechanisms,” he said. “If we can understand these, we might be able to use them as an alternative to harmful chemicals.”

What Howe and his assistants have researched is how tomato plants naturally repel predators. The resistance is triggered by a chemical found in plants called jasmonic acid. When an attack by a predator is felt, the acid produces a reaction which releases the plant’s defense mechanisms, he said.

“Plants have been defending themselves this way for years,” Howe said. “What we’ve discovered in tomato plants can be used in other crops as well.”

When the attack is sensed by a plant, it releases a hormone that gives the imposing insect a stomachache. At the same time the plant releases another chemical which lures the insect’s natural predators.

“To understand this complex system we’ve created mutations of plants without jasmonic acid,” Howe said. “We isolate the mutant plants and compare them with their natural counterparts.”

Lei Li, a genetics graduate student, is researching the isolated mutant plants to determine exactly how the process works.

“Right now we’re trying to understand how jasmonic acid works to regulate plant defenses,” Li said. “My job is to characterize these mutants’ response to stress, (predator) attack and other stimuli.”

If they find the responses researchers are looking for, they could produce a much better, natural tool to protect plants, he said.

David Shaffer, a biology junior, has been working with Howe for more than a year and plays a large role in screening mutated plants for jasmonic acid levels.

“Professor Howe treats this project like work, but in a way it really feels like a class because he’s always open to questions,” Shaffer said. “He always makes sure I understand the scientific principles behind the work instead of the work itself.”

Shaffer looks for the mutated tomato plants with very little defense to herbivores and compares them with plants from the wild.

“He’s a really great person to work for,” Shaffer said. “All the experiences I’ve had with him have been positive.”


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