Skip to main content
PMC home page
Plant Physiology logoLink to Plant Physiology
. 1986 Jul;81(3):731–736. doi: 10.1104/pp.81.3.731

Metabolism of Unsaturated Monogalactosyldiacylglycerol Molecular Species in Arabidopsis thaliana Reveals Different Sites and Substrates for Linolenic Acid Synthesis

Helen A Norman 1, Judith B St John 1
PMCID: PMC1075417  PMID: 16664893

Abstract

Synthesis of unsaturated monogalactosyldiacylglycerol (MGDG) was examined in a mutant of Arabidopsis thaliana (L.) Heynh. containing reduced levels of hexadecatrienoic (16:3) and linolenic (18:3) acids in leaf lipids. Molecular species composition and labeling kinetics following the incorporation of exogenous [14C]fatty acids suggest that at least two pathways and multiple substrates are involved in desaturation of linoleic acid (18:2) to 18:3 for production of unsaturated galactolipids. A reduction in 18:3/16:3 MGDG and an increase in 18:2/16:2 MGDG, together with labeling kinetics of these molecular species following the incorporation of exogenous [14C]12:0 fatty acids, suggests that a chloroplastic pathway for production of 18:3 at the sn-1 position of MGDG utilizes 18:2/16:2 MGDG as a substrate. This chloroplastic (prokaryotic) pathway is deficient in the mutant. When exogenous [14C]18:1 was supplied, a eukaryotic (cytoplasmic) pathway involving the desaturation of 18:2 to 18:3 on phosphatidylcholine serves as the source of 18:3 for the sn-2 position of MGDG. This eucaryotic pathway predominates in the mutant.

Full text

PDF
731

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. BLIGH E. G., DYER W. J. A rapid method of total lipid extraction and purification. Can J Biochem Physiol. 1959 Aug;37(8):911–917. doi: 10.1139/o59-099. [DOI] [PubMed] [Google Scholar]
  2. Lynch D. V., Thompson G. A. Microsomal Phospholipid Molecular Species Alterations during Low Temperature Acclimation in Dunaliella. Plant Physiol. 1984 Feb;74(2):193–197. doi: 10.1104/pp.74.2.193. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. MORRISON W. R., SMITH L. M. PREPARATION OF FATTY ACID METHYL ESTERS AND DIMETHYLACETALS FROM LIPIDS WITH BORON FLUORIDE--METHANOL. J Lipid Res. 1964 Oct;5:600–608. [PubMed] [Google Scholar]
  4. Norman H. A., Smith L. A., Lynch D. V., Thompson G. A., Jr Low-temperature-induced changes in intracellular fatty acid fluxes in Dunaliella salina. Arch Biochem Biophys. 1985 Oct;242(1):157–167. doi: 10.1016/0003-9861(85)90489-8. [DOI] [PubMed] [Google Scholar]
  5. Norman H. A., Thompson G. A., Jr Effects of low-temperature stress on the metabolism of phosphatidylglycerol molecular species in Dunaliella salina. Arch Biochem Biophys. 1985 Oct;242(1):168–175. doi: 10.1016/0003-9861(85)90490-4. [DOI] [PubMed] [Google Scholar]
  6. Ramesha C. S., Thompson G. A., Jr Cold stress induces in situ phospholipid molecular species changes in cell surface membranes. Biochim Biophys Acta. 1983 Jun 10;731(2):251–260. doi: 10.1016/0005-2736(83)90016-0. [DOI] [PubMed] [Google Scholar]
  7. Roughan P. G., Batt R. D. Quantitative analysis of sulfolipid (sulfoquinovosyl diglyceride) and galactolipids (monogalactosyl and digalactosyl diglycerides) in plant tissues. Anal Biochem. 1968 Jan;22(1):74–88. doi: 10.1016/0003-2697(68)90261-3. [DOI] [PubMed] [Google Scholar]
  8. Roughan P. G., Holland R., Slack C. R. The role of chloroplasts and microsomal fractions in polar-lipid synthesis from [1-14C]acetate by cell-free preparations from spinach (Spinacia oleracea) leaves. Biochem J. 1980 Apr 15;188(1):17–24. doi: 10.1042/bj1880017. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Smith L. A., Norman H. A., Cho S. H., Thompson G. A., Jr Isolation and quantitative analysis of phosphatidylglycerol and glycolipid molecular species using reversed-phase high-performance liquid chromatography with flame ionization detection. J Chromatogr. 1985 Oct 18;346:291–299. doi: 10.1016/s0021-9673(00)90515-6. [DOI] [PubMed] [Google Scholar]
  10. Williams J. P., Watson G. R., Leung S. P. Galactolipid Synthesis in Vicia faba Leaves: II. Formation and Desaturation of Long Chain Fatty Acids in Phosphatidylcholine, Phosphatidylglycerol, and the Galactolipids. Plant Physiol. 1976 Feb;57(2):179–184. doi: 10.1104/pp.57.2.179. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES