Wednesday Explorers Club ~ Plant defense against invaders

Sweet potato. photo by Anja Meents, Max Planck Institute for Chemical Ecology

If a hungry predator threatens you, you can run away. You can also yell at your friends to warn them to run away too.

But what about plants? They can't run anywhere. But they have a lot of ways to defend themselves. Think: thorny roses, needle-sharp cactus spines, stinging nettle hairs. When I was writing Are Ants Like Plants, I learned how some plants can even warn their neighbors by sending a chemical message. Yesterday scientists at the Max Planck Institute for Chemical Ecology in Jena, Germany, and at the National Taiwan University released a study about how a sweet potato uses a single odor to warn its neighbors of insect attack.

First the researchers wanted to know what happened in a particular variety of sweet potato after it was attacked by leaf-munching bugs. That's because the variety was more resistant to insect attacks than other varieties. The resistant sweet potato plants produced a plant hormone in the damaged leaves - and emitted odors.

Cool thing #1: Leaves that weren't attacked by the insects also produced the same hormone - a protein that made the attacking insects lose their appetite (it affected the insects' digestive system).

Cool thing #2: Plants growing nearby that hadn't been attacked by the insects also produced the anti-herbivore protein.

Turns out, the neighboring plants could detect the odor emitted by the insect-nibbled plants, allowing them to prepare their defense against invading leaf-munchers. Pretty nifty trick for plants, right? Makes you wonder what else we can learn by studying plants.

You can learn more about this study here and about another study (at Cornell University) here. Check out this earlier article in the Scientist.