Abstract
Phospholipase D (PLD) is the enzyme that hydrolyzes glycerophospholipids, a major component of biological membranes, to produce phosphatidic acid, a signaling molecule on membranes. Plants encode two classes of PLD; one exists generally in eukaryotes and contains PX and PH domains, and the other exists specifically in plants and contains a C2 domain. PLDζ1 is one of the two PX-PH-type PLDs in Arabidopsis thaliana. Its gene has been reported to be directly regulated by the transcription factor GL2 and act as a positive factor for root hair formation during root hair patterning. Examined T-DNA insertion mutants of the gene, however, have shown no significant phenotypes in root hair patterning. We found that another T-DNA insertion line, which is likely to be a loss-of-function mutant of the gene, exhibited unstable, but significant abnormality in growth. This low-penetrance phenotype could be complemented with a transgene encoding PLDζ1-YFP, confirming that the phenotype is due to a defect in the PLDζ1 gene function. Using this transgenic line, we investigated intracellular localization of the functional PLDζ1 fusion protein.
