Previous work has demonstrated that plant leaf polar lipid fatty acid composition varies during the diurnal (dark–light) cycle. Fatty acid synthesis occurs primarily during the light, but fatty acid desaturation continues in the absence of light, resulting in polyunsaturated fatty acids reaching their highest levels toward the end of the dark period. In this work, Arabidopsis thaliana were grown at constant (21°C) temperature with 12-h light and 12-h dark periods. Collision induced dissociation time-of-flight mass spectrometry (MS) demonstrated that 16:3 and 18:3 fatty acid content in membrane lipids of leaves are higher at the end of the dark than at the end of the light period, while 16:1, 16:2, 18:0, and 18:1 content are higher at the end of the light period. Lipid profiling of membrane galactolipids, phospholipids, and lysophospholipids by electrospray ionization triple quadrupole MS indicated that the monogalactosyldiacylglycerol, phosphatidylglycerol, and phosphatidylcholine classes include molecular species whose levels are highest at end of the light period and others that are highest at the end of the dark period. The levels of phosphatidic acid (PA) and phosphatidylserine classes were higher at the end of the dark period, and molecular species within these classes either followed the class pattern or were not significantly changed in the diurnal cycle. Phospholipase D (PLD) is a family of enzymes that hydrolyzes phospholipids to produce PA. Analysis of several PLD mutant lines suggests that PLDζ2 and possibly PLDα1 may contribute to diurnal cycling of PA. The polar lipid compositional changes are considered in relation to recent data that demonstrate phosphatidylcholine acyl editing.
Keywords: Arabidopsis thaliana leaves, diurnal cycle, galactolipids, lipidomics, mass spectrometry, phosphatidic acid, phospholipase D, phospholipids
Citation: Maatta S, Scheu B, Roth MR, Tamura P, Li M, Williams TD, Wang X and Welti R (2012) Levels of Arabidopsis thaliana leaf phosphatidic acids, phosphatidylserines, and most trienoate-containing polar lipid molecular species increase during the dark period of the diurnal cycle. Front. Plant Sci. 3:49. doi: 10.3389/fpls.2012.00049
Received: 17 December 2011; Accepted: 27 February 2012;
Published online: 14 March 2012.
Edited by:Kent D. Chapman, University of North Texas, USA
Reviewed by:Changcheng Xu, Brookhaven National Laboratory, USA
Copyright: © 2012 Maatta, Scheu, Roth, Tamura, Li, Williams, Wang and Welti. This is an open-access article distributed under the terms of the Creative Commons Attribution Non Commercial License, which permits non-commercial use, distribution, and reproduction in other forums, provided the original authors and source are credited.
*Correspondence: Ruth Welti, Division of Biology, Kansas Lipidomics Research Center, Kansas State University, Manhattan, KS 66506-4901, USA. e-mail: firstname.lastname@example.org