Leaf lipids of Ribes nigrum: a plant containing 16:3, α-18:3, γ-18:3 and 18:4 fatty acids

The glycerolipid composition of Ribes nigrum (blackcurrant) leaves was determined. The total fatty acid composition was unusual in that α-linolenic acid (α-18:3) occurred together with cis-7,10,13-hexadecatrienoic acid (16:3) and lower amounts of stearidonic acid (18:4) and γ-linolenic acid (γ-18:3). Monogalactosyldiacylglycerol contained the highest proportion of 16:3 with less in digalactosyldiacylglycerol. γ-18:3 and 18:4 were present in all lipids and 18:4 was always greater than γ-18:3. The highest percentages of γ-18:3 and 18:4 were in phosphatidylcholine, but phosphatidylglycerol was particularly low in these acids. In summary, the lipid composition was largely typical of 16:3 plants but there was a minor contribution typical of 18:4 plants. The possibility of three pathways for glycolipid biosynthesis is discussed.