Plants under attack communicate with common 'language molecules': Study

In a first, researchers have found that the smell molecules plants use to communicate with each other when under attack become more similar over the time of the threat -- an advance that could help improve plant-to-plant interactions in organic agriculture to protect crops.

The study, published in the journal Current Biology, noted that plants secrete airborne chemicals known as volatile organic compounds (VOCs) which transfer information among plants.

The researchers, including those from Cornell University in the US, found that the messages tended to converge on the same language -- or the same warning signs -- to share the information freely between individual plants.

The team conducted experiments on Solidago altissima -- a species of goldenrod native to the northeastern parts of the US -- and monitored the reactions of the plant to the herbivorous goldenrod leaf beetle.

The researchers found that neighboring plants picked up on the warning signals in the form of VOCs, and prepared for the perceived threat, such as an incoming insect pest.

"What we very often see when plants get attacked by pathogens or herbivores is, they change their metabolism," said Andre Kessler, co-author of the study from Cornell University.

Kessler added that the metabolism change was not random but meant to help the plants cope with the attackers.

"It's very much like our immune system: though plants don't have antibodies like we have, they can fight back with pretty nasty chemistry," Kessler said.

He added that the information exchange converged on the same language, becoming independent of how closely related the plants were.

The study noted that these language molecules included defensive compounds that can attract predacious insects, or parasitoids, which kill the herbivore and save the plant.

The findings could have practical applications around the world, according to the researchers, such as in understanding plant-to-plant interactions in organic agriculture to protect crop plants, especially in intercropping systems.

"We are involved in work on a system in Kenya - called 'push-pull' and developed by the International Center for Insect Physiology and Ecology - which is based on manipulating the flow of information to control a pest in corn fields," Kessler said.