International Research Team Finds Novel Function of Plant Hormone Jasmonic Acid

An international research team led by plant biologist Dirk Becker of Julius-Maximilians-Universität Würzburg (JMU) in Bavaria, Germany, reports on their novel findings that the plant hormone jasmonic acid is involved in the quick closure of stomata.

Jasmonic acid is responsible for the aromatic odor of the plant Jasminum grandiflorum used in cosmetics and perfume industries. When wounded, plants produce jasmonic acid as a defense signal, as a phytohormone to mount their defense responses, including the formation of toxic substances. They even employ volatile derivatives of jasmonic acid to warn their neighbors to fight the rising threat in time.

Stomata are adjustable pores formed by two guard cells in the epidermis of plant leaves. They control the uptake of carbon dioxide and the plants' water balance. The phytohormone abscisic acid (ABA) represents a key signal for stomatal closure. Plants produce ABA during drought stress to save water. In their experiments on guard cell volume control by biotic stress, the team noticed that mechanical wounding of leaves of the model plant Arabidopsis thaliana quickly triggers stomatal closure, too. They also noticed that this effect was not restricted to the wounded leaf, but also occurred in neighboring leaves. Professor Becker explains that this observation was not reported before and suggests that the jasmonate signaling pathway might have been turned-on in the guard cells.

For more details, read the news release from JMU.