Document Type

Article

Abstract

Rapid activation of phospholipase D (PLD), which hydrolyzes membrane lipids to generate phosphatidic acid (PA), occurs under various hyperosmotic conditions, including salinity and water deficiency. The Arabidopsis thaliana PLD family has 12 members, and the function of PLD activation in hyperosmotic stress responses has remained elusive. Here, we show that knockout (KO) and overexpression (OE) of previously uncharacterized PLDα3 alter plant response to salinity and water deficit. PLDα3 uses multiple phospholipids as substrates with distinguishable preferences, and alterations of PLDα3 result in changes in PA level and membrane lipid composition. PLDα3-KO plants display increased sensitivities to salinity and water deficiency and also tend to induce abscisic acid–responsive genes more readily than wild-type plants, whereas PLDα3-OE plants have decreased sensitivities. In addition, PLDα3-KO plants flower later than wild-type plants in slightly dry conditions, whereas PLDα3-OE plants flower earlier. These data suggest that PLDα3 positively mediates plant responses to hyperosmotic stresses and that increased PLDα3 expression and associated lipid changes promote root growth, flowering, and stress avoidance.

Publication Date

March 2008

Publication Title

The Plant Cell

Volume

20

First Page

803

Last Page

816

Comments

© American Society of Plant Biologists.

DOI

10.1105/tpc.107.056390

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