Received June 22, 2006
Accepted July 28, 2006
Quantitative Profiling of Arabidopsis Polar Glycerolipids in Response to Phosphate Starvation. Roles of PLDæ1 and PLDæ2 in Phosphatidylcholine Hydrolysis and Digalactosyldiacylglycerol Accumulation in Phosphate-starved Root
Maoyin Li , Ruth Welti , and Xuemin Wang *
Department of Biology, University of Missouri, St. Louis, MO 63121 and Danforth Plant Science Center, St. Louis, MO 63132
Division of Biology, Kansas State University, Manhattan, KS, 66506
* Corresponding author; email: wangxue{at}umsl.edu.
Phosphorus is an essential macronutrient that often limits plant growth and development. Under phosphorus-limited conditions, plants undergo substantial alterations in membrane lipid composition to cope with phosphorus deficiency. To characterize the changes in lipid species and to identify enzymes involved in plant response to phosphorus starvation, 140 molecular species of polar glycerolipids were quantitatively profiled in rosettes and roots of wild-type Arabidopsis thaliana and phospholipase D knockout mutants, pld
1, pld2, and pld1pld2. In response to phosphorus starvation, the concentration of phospholipids was decreased and that of galactolipids was increased. Phospholipid lost in phosphorus-starved Arabidopsis rosettes was replaced by an equal amount of galactolipid. The concentration of phospholipid lost in roots was much greater than in rosettes. Disruption of both PLD1 and PLD2 function resulted in a smaller decrease in phosphatidylcholine (PC) and a smaller increase in digalactosyldiacylglycerol (DGDG) in phosphorus-starved roots. The results suggest that hydrolysis of PC by PLDs during phosphorus starvation contributes to the supply of inorganic phosphorus for cell metabolism and diacylglycerol moieties for galactolipid synthesis.
