Arabidopsis PLDs with C2-domain function distinctively in hypoxia

Area of Science:

• Plant Physiology
• Molecular Biology
• Biochemistry

Background:

• Hypoxia (oxygen deprivation) disrupts plant metabolism, growth, and development.
• Phospholipase D (PLD) signaling pathways are known to mediate plant responses to various environmental stresses.

Purpose of the Study:

• To investigate the role of Phospholipase D (PLD) isoforms in plant signaling during hypoxia.
• To determine how PLDs influence cytosolic calcium (Ca2+cyt), reactive oxygen species (ROS), and phosphatidic acid (PA) levels under oxygen deprivation.

Main Methods:

• Utilized wild type Arabidopsis thaliana and 10 pld isoform mutants.
• Measured Ca2+cyt and ROS levels using fluorescence microscopy and confocal imaging.
• Quantified PA levels via an enzymatic method in mesophyll protoplasts.

Main Results:

• All 10 PLD isoform mutants showed reduced elevations in Ca2+cyt and PA under hypoxia.
• Different PLD isoforms exhibited distinct kinetic patterns in response to hypoxia-induced Ca2+ and ROS changes.
• Pharmacological experiments confirmed both external and internal sources contribute to hypoxia-induced Ca2+ and ROS accumulation.

Conclusions:

• PLDα1-3, PLDβ1, and PLDγ1-3 are implicated in calcium signaling and PA production during hypoxia.
• Most investigated PLDs, excluding PLDγ3, play a role in hypoxia-induced ROS elevation.
• PLDs are essential components of the plant signaling network responding to oxygen deprivation.