Low temperature-induced accumulation of eicosapentaenoic acids in Marchantia polymorpha cells

The composition of fatty acids in suspension-cultured cells from the liverw ort Marchantia polymorpha L. grown at 25 and 15 degrees C was analyzed. The liverwort cells grown at 25 degrees C contained approximately 18% linoleni c acid (18:3 omega 3), 11% arachidonic acid (20:4 omega 6) and 3% eicosapen taenoic acid (20:5 omega 3) as percentages of total fatty acids. When the c ells were grown at 15 degrees C, the relative amounts of 18:3 and 20:5 show ed a large increase, while those of other fatty acids were less affected. S ubcellular fractionation experiments showed that the levels of 20:4 and 20: 5 were increased in the chloroplast fraction but not in the extrachloroplas t fraction, while the level of 18:3 was increased in both fractions. Lipid analysis revealed that galactolipids were present in chloroplasts, PE (phos phatidylethanolamine) in the extrachloroplast fraction and PC (phosphatidyl choline), PG (phosphatidylgiycerol), PI (phosphatidylinositol) and DAG (dia cylglycerol) in both compartments. Of lipid species bound to 20:5, only MGD G (monogalactosyldiacylglycerol) and chloroplastic PC were increased by low temperature. (C) 1999 Elsevier Science Ltd. All rights reserved.