How bean plants sense very hungry caterpillars and call for backup

Plants may not appear aggressive, but they can still defend themselves while under attack. When caterpillars chomp the leaves of bean plants, these plants release gases that lure predatory wasps. The wasps prey on the caterpillars, saving the plants from further destruction. In a paper published May 27 in Science Advances, a UW-led team demonstrated that this defense strategy is run by a protein called INR, or inceptin receptor. The researchers grew bean plants with naturally occurring mutations in the INR gene alongside plants with functional INR in an experimental field in Oaxaca, Mexico. The knock-out plants didn't emit gases and attracted far fewer wasps. This result helps explain a previous study by this team that first identified the biochemical pathway behind this defense mechanism. These results also showcase how the tiny actions of a single protein can affect the behavior of wasps and caterpillars, and in turn, protect the health of the plant. This could benefit nearby plants as well, the researchers said. Beans are often grown alongside "companion crops," such as corn, with the idea that each plant provides a benefit for the others. Beans help make the soil richer for their companions, and, through the actions of INR, could also protect their neighbors from pests.

For more information, contact senior author Adam Steinbrenner, UW associate professor of biology, at astein10@uw.edu.  

The other UW co-authors are Natalia Guayazán Palacios, Brian Behnken, Di Wu, Antonio Chaparro and Benjamin Sheppard. A full list of co-authors and funding is included in the paper.