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United States Department of Agriculture

Agricultural Research Service

Plants Can Fight Off Foreign Invaders

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Animated graphic of a chomping plant trying to catch flying bug.Animated graphic of another chomping plant trying to catch flying bug.

Plants Fight Off
Foreign Invaders

Did you know that your body contains millions of tiny soldiers to protect it? Yep, like when you fall and skin your knee. Immediately, thousands of teeny-weeny, microscopic good guys called antibodies rush to the injury. They keep your skin from getting infected by bacteria in the dirt or on the sidewalk where you fell.

The antibody army is part of your own immune system. Plants have a similar kind of built-in protection. When a bug lands on a plant leaf and starts to chew it, something in its spit, or saliva, tells the plant that it’s time to start fighting back. These “somethings” are PR proteins.

Okay, pop quiz time. Aw, quit whining. It'll be fun! Here goes: What do you think the “PR” stands for?

A. Pathogenesis Related
B. Public Relations
C. Plant Rescue

PR proteins start operating when an outside enemy like an insect or a disease attacks a plant. But sometimes the damage from outside invaders can overwhelm a plant before the proteins can shift into high gear.

These proteins need more help, so the plant has a better chance to save itself. And that’s just what Agricultural Research Service chemist Hamed Doostdar is trying to do.

Doostdar and his colleagues at the U.S. Horticultural Research Laboratory in Orlando, Florida, have found the genes responsible for making PR proteins in citrus. By tinkering with these genes, they hope to make the plants produce more PR proteins.

The Orlando scientists are doing other neat things to help plants better protect themselves. On tomato plants, they’re spraying safe chemicals that cause a chemical reaction in the plants. This reaction keeps insects, like leafminers, from eating the plant.

If plants can better defend themselves, farmers and gardeners could rely less on chemicals to protect their crops from insects and diseases. Not only would this help keep the environment cleaner, but it would also save farmers money.

—By Doris Stanley, formerly with the Information Staff, Agricultural Research Service

To learn more, check out theAgricultural Research story Exploiting Plants' Protective Proteins.

U.S. Horticultural Research Laboratory, Orlando, Fla.

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Last Modified: 2/14/2011
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