Phospholipase D and phosphatidic acid signalling in plant response to drought and salinity

The activity of phospholipase D (PLD) in plants increases under different hyperosmotic stresses, such as dehydration, drought, and salinity. Recent results begin to shed light onto the involvement of PLD in response to water deficits and salinity. Different PLDs have unique and overlapping functions in these responses. PLDa1 promotes stomatal closure and reduces water loss. PLDa1 and PLDd are involved in seedling tolerance to salt stress. PLDa3 and PLDe enhance plant growth and hyperosmotic tolerance. The different PLDs regulate the production of phosphatidic acid (PA) that is a key class of lipid mediators in plant response to environmental stresses. Further studies on the upstream regulators that activate different PLDs and the downstream effectors of PLDs and PA have the potential to unveil the linkage between the stimulus perception at the cell membrane to intracellular responses to drought and salinity stresses.