Flipping the stress tolerance switch

Many plants have evolved to endure harsh environmental conditions, yet the detailed mechanisms of plant stress resistance have long remained unclear. A single plant hormone, abscisic acid (ABA), has been known to play a central regulatory role in such resistance, holding the key to advances in the development of stress-resistant crops.

In results published this month in the Proceedings of the National Academy of Sciences, research teams at RIKEN and the Japan Science and Technology Agency (JST) have for the first time unlocked the secret to ABA-mediated signaling. The teams demonstrated that a protein phosphatase (PP2C) interacts with a protein kinase (SnRK2) to regulate the elusive ABA signal transmission pathway, acting as an ON/OFF switch.

Combining this discovery with the recent finding that PP2C activity is regulated by ABA receptors (RCAR and PYR), the researchers went on to trace the ABA signal pathway itself. In conditions of high environmental stress, they showed that ABA production leads ABA receptors to suppress PP2C, which in turn results in activation of SnRK2, flipping the ABA “switch” and triggering various stress response mechanisms.

Elucidation of the mechanism underlying ABA signaling has wide-ranging implications for plant science. In addition to its role in regulating resistance to drought, salt and cold, ABA contributes to defending against disease and pests, while also functioning at various stages of plant development. Applications are anticipated in the development of stress-resistant crops, in the improvement of seed stability, and in the control of pre-harvest sprouting.

For more information, please contact:

Dr. Taishi Umezawa
Gene Discovery Research Group
RIKEN Plant Science Center
Tel: +81-(0) 29-836-4359 / fax: +81-(0) 29-836-9060
Ms. Saeko Okada (PI officer)
Global Relations Office
RIKEN
Tel: +81-(0)48-462-1225 / Fax: +81-(0)48-467-9443
Email: koho@riken.jp