Stomatal opening under high temperatures is controlled by the OST1-regulated TOT3-AHA1 module.

Area of Science:

• Plant Physiology
• Molecular Biology
• Environmental Stress Response

Background:

• Plants regulate gas exchange and water loss via stomata.
• Environmental factors like temperature and drought trigger opposing stomatal responses.
• Cellular mechanisms for resolving conflicting stress signals in stomata remain unclear.

Purpose of the Study:

• To elucidate the cellular mechanisms governing stomatal responses to combined heat and drought stress.
• To identify key molecular players involved in harmonizing stomatal signaling pathways.

Main Methods:

• Investigated the role of the kinase TARGET OF TEMPERATURE 3 (TT3) in high-temperature-induced stomatal opening.
• Examined the interaction between TT3 and OPEN STOMATA 1 (OST1) in response to drought stress.
• Utilized molecular and physiological techniques to analyze stomatal regulation.

Main Results:

• TARGET OF TEMPERATURE 3 directly activates plasma membrane H+-ATPases, promoting stomatal opening in response to high temperatures.
• OPEN STOMATA 1 phosphorylates and inactivates TARGET OF TEMPERATURE 3, mediating stomatal closure during drought.
• A novel signaling axis integrating heat and drought signals for stomatal control was identified.

Conclusions:

• The TT3-OST1 signaling module reconciles conflicting stomatal responses to concurrent heat and drought stresses.
• This pathway is critical for maintaining plant homeostasis under adverse environmental conditions.
• Understanding this mechanism is vital for developing climate-resilient crops.