Biology researcher discovers new role for jasmonic acid in plants

A research team led by University of Florida Genetics Institute member Sixue Chen, PhD, recently discovered a new role for jasmonic acid in plants.

Scientists have long been aware of the existence of jasmonic acid, and its role associated with defense from predators. However, they were previously unaware of its role in stomata regulation in response to high levels of carbon dioxide.

Chen, a Professor in the department of biology, published a paper in The Plant Journal that describes this discovery. Chen also serves as faculty director of the Proteomics and Mass Spectrometry core at the Interdisciplinary Center for Biotechnology Research.

Plant response to rising levels of CO₂ is significant considering how human activity continues to introduce more of it into the atmosphere. Current levels of CO₂ are approximately 380 parts per million, Chen said. They are projected to reach 550ppm by 2050. The worldwide human population is projected to hit 9 billion at the same time.

“What do we need? We need food,” he said. “We have to increase food production by 70 percent to feed 9 billion people.”

However, while some studies suggest that minor increases in CO₂ levels boost photosynthesis– the process whereby plants use CO₂ and water to produce sugar to feed themselves– too much CO₂ can inhibit the process.

Plants absorb CO₂ and evaporate water through openings on their leaves called stomata. When CO₂ levels rise nearby, plants close their stomata, in order to avoid releasing too much water, and becoming dehydrated.

Chen’s research team introduced a plant to high levels of CO₂ to trigger its stomata to close. After examining the plant, they were surprised to find increased level of jasmonic acid.

To determine whether jasmonic acid has a role in stomatal control, Chen’s lab tested a mutant plant that is unable to detect the metabolite. When exposed to high levels of CO₂, the plant’s stomata remained open.

The lab also tested mutant plants that were incapable of producing jasmonic acid. When the CO₂ levels rose, the stomata remained open.

Chen said their eventual goal is to devise a way to compel plant stomata to remain open when CO₂ levels rise. Doing so would provide a two-fold benefit– ensuring high yield, while preventing the plant from becoming dehydrated.

Chen’s work was supported by US National Science Foundation grants NSF-0818051, NSF-1412547 and NSF-1158000.