The plasma membrane-bound phospholipase Dδ enhances freezing tolerance in Arabidopsis thaliana

Freezing injury is a major environmental limitation on the productivity and geographical distribution of plants. Here we show that freezing tolerance can be manipulated in Arabidopsis thaliana by genetic alteration of the gene encoding phospholipase Dδ (PLDδ), which is involved in membrane lipid hydrolysis and cell signaling. Genetic knockout of the plasma membrane–associated PLDδ rendered A. thaliana plants more sensitive to freezing, whereas overexpression of PLDδ increased freezing tolerance. Lipid profiling revealed that PLDδ contributed approximately 20% of the phosphatidic acid produced in wild-type plants during freezing, and overexpression of PLDδ increased the production of phosphatidic acid species. The PLDδ alterations did not affect the expression of the cold-regulated genes COR47 or COR78 or alter cold-induced increases in proline or soluble sugars, suggesting that the PLD pathway is a unique determinant of the response to freezing and may present opportunities for improving plant freezing tolerance.