Editing of phosphatidic acid and phosphatidylethanolamine by acyl-CoA: lysophospholipid acyltransferases in developing Camelina sativa seeds

• Published in: Planta 2020-07, Vol.252 (1), p.4-4, Article 4
• Main Authors: Klińska, Sylwia, Jasieniecka-Gazarkiewicz, Katarzyna, Demski, Kamil, Banaś, Antoni
• Format: Article
• Language: English
• Subjects: 1-Acylglycerophosphocholine O-Acyltransferase - genetics; 1-Acylglycerophosphocholine O-Acyltransferase - metabolism; Acyl Coenzyme A - metabolism; Agriculture; Biomedical and Life Sciences; Biosynthesis; Calcium; Camelina sativa; Camellia - enzymology; Camellia - genetics; Camellia - growth & development; Ecology; Esterification; Fatty acids; Fatty Acids - metabolism; Fish oils; Forestry; Ions; Lecithin; Life Sciences; Lipids; Lysophosphatidic acid; Lysophospholipids - metabolism; Magnesium; Original; Original Article; pH effects; Phosphatidic acid; Phosphatidic Acids - metabolism; Phosphatidylcholine; Phosphatidylcholines - metabolism; Phosphatidylethanolamine; Phosphatidylethanolamines - metabolism; Phospholipids; Plant Sciences; Seeds; Seeds - enzymology; Seeds - genetics; Seeds - growth & development
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-020-03408-z

Main conclusions The main source of polyunsaturated acyl-CoA in cytoplasmic acyl-CoA pool of Camelina sativa seeds are fatty acids derived from phosphatidylcholine followed by phosphatidic acid. Contribution of phosphatidylethanolamine is negligible. While phosphatidylethanolamine (PE) is the second most abundant phospholipid, phosphatidic acid (PA) only constitutes a small fraction of C. sativa seeds’ polar lipids. In spite of this, the relative contribution of PA in providing fatty acids for the synthesis of acyl-CoA, supplying cytosolic acyl-CoA pool seems to be much higher than the contribution of PE. Our data indicate that up to 5% of fatty acids present in mature C. sativa seeds are first esterified with PA, in comparison to 2% first esterified with PE, before being transferred into acyl-CoA pool via backward reactions of either acyl-CoA:lysophosphatidic acid acyltransferases ( Cs LPAATs) or acyl-CoA:lysophoshatidylethanolamine acyltransferases ( Cs LPEATs). Those acyl-CoAs are later reused for lipid biosynthesis or remodelling. In the forward reactions both aforementioned acyltransferases display the highest activity at 30 °C. The spectrum of optimal pH differs for both enzymes with Cs LPAATs most active between pH 7.5–9.0 and Cs LPEATs between pH 9.0 to 10.0. Whereas addition of magnesium ions stimulates Cs LPAATs, calcium and potassium ions inhibit them in concentrations of 0.05–2.0 mM. All three types of ions inhibit Cs LPEATs activity. Both tested acyltransferases present the highest preferences towards 16:0-CoA and unsaturated 18-carbon acyl-CoAs in forward reactions. However, Cs LPAATs preferentially utilise 18:1-CoA and Cs LPEATs preferentially utilise 18:2-CoA while catalysing fatty acid remodelling of PA and PE, respectively.