Phospholipase D[epsilon] and phosphatidic acid enhance Arabidopsis nitrogen signaling and growth

• Published in: The Plant journal : for cell and molecular biology 2009-05, Vol.58 (3), p.376
• Main Authors: Hong, Yueyun, Devaiah, Shivakumar P, Bahn, Sung Chul, Thamasandra, Bharath N, Li, Maoyin, Welti, Ruth, Wang, Xuemin
• Format: Article
• Language: English
• Subjects: Botany; Cellular biology; Genetics; Lipids; Nitrogen
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/j.1365-313X.2009.03788.x

Activation of phospholipase D (PLD) produces phosphatidic acid (PA), a lipid messenger implicated in cell growth and proliferation, but direct evidence for PLD and PA promotion of growth at the organism level is lacking. Here we characterize a new PLD gene, PLD[epsilon], and show that it plays a role in promoting Arabidopsis growth. PLD[epsilon] is mainly associated with the plasma membrane, and is the most permissive of all PLDs tested with respect to its activity requirements. Knockout (KO) of PLD[epsilon] decreases root growth and biomass accumulation, whereas over-expression (OE) of PLD[epsilon] enhances root growth and biomass accumulation. The level of PA was higher in OE plants, but lower in KO plants than in wild-type plants, and suppression of PLD-mediated PA formation by alcohol alleviated the growth-promoting effect of PLD[epsilon]. OE and KO of PLD[epsilon] had opposite effects on lateral root elongation in response to nitrogen. Increased expression of PLD[epsilon] also promoted root hair elongation and primary root growth under severe nitrogen deprivation. The results suggest that PLD[epsilon] and PA promote organism growth and play a role in nitrogen signaling. The lipid-signaling process may play a role in connecting membrane sensing of nutrient status to increased plant growth and biomass production. [PUBLICATION ABSTRACT]