Abstract
A root hair is formed by tip-growth of a root hair cell. It was proposed that phospholipase D (PLD) ζ1 is involved in root-hair cell morphogenesis (Ohashi Y et al. 2003.). This suggested that root-hair cell morphogenesis is controlled by lipid signal transduction. On the other hand, it was revealed that phosphatidyl inositol bisphosphate stimulates many kinds of signaling molecules including Phospholipase D in animal cells. To clarify the mechanism of the root-hair cell morphogenesis, we focused on phosphatidyl inositol phosphate kinase (PIPK). The Arabidopsis genome contains 11 PIPK genes. Northern hybridization analysis revealed that AtPIPK3 was preferentially expressed in roots. T-DNA insertion mutants of AtPIPK3 gene were analyzed, and their root-hair lengths were significantly reduced. In addition, gene expression and the intracellular localization of the AtPIPK3 protein is analyzed. These results suggests that AtPIPK3 gene take part in the root hair tip-growth.
