We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Heterologous expression of a fatty acid hydroxylase gene in developing seeds of Arabidopsis thaliana.
- Authors
Mark A. Smith; Hangsik Moon; Gangamma Chowrira; Ljerka Kunst
- Abstract
Expression of a cDNA encoding the castor bean ( Ricinus communis L.) oleate ?12-hydroxylase in the developing seeds of Arabidopsis thaliana (L.) Heynh. results in the synthesis of four novel hydroxy fatty acids. These have been previously identified as ricinoleic acid (12-hydroxy-octadec- cis-9-enoic acid: 18:1-OH), densipolic acid (12-hydroxy-octadec- cis-9,15-enoic acid: 18:2-OH), lesquerolic acid (14-hydroxy-eicos- cis-11-enoic acid: 20:1-OH) and auricolic acid (14-hydroxy-eicos- cis-11,17-enoic acid: 20:2-OH). Using mutant lines of Arabidopsis that lack the activity of the FAE1 condensing enzyme or FAD3 ER ?-15-desaturase, we have shown that these enzymes are required for the synthesis of C20 hydroxy fatty acids and polyunsaturated hydroxy fatty acids, respectively. Analysis of the seed fatty acid composition of transformed plants demonstrated a dramatic increase in oleic acid (18:1) levels and a decrease in linoleic acid (18:2) content correlating to the levels of hydroxy fatty acid present in the seed. Plants in which FAD2 (ER ?12-desaturase) activity was absent showed a decrease in 18:1 content and a slight increase in 18:2 levels corresponding to hydroxy fatty acid content. Expression of the castor hydroxylase protein in yeast indicates that this enzyme has a low level of fatty acid ?12-desaturase activity. Lipase catalysed 1,3-specific lipolysis of triacylglycerol from transformed plants demonstrated that ricinoleic acid is not excluded from the sn-2 position of triacylglycerol, but is the only hydroxy fatty acid present at this position.
- Subjects
CASTOR beans; ARABIDOPSIS thaliana; SEED development; FATTY acids
- Publication
Planta: An International Journal of Plant Biology, 2003, Vol 217, Issue 3, p507
- ISSN
0032-0935
- Publication type
Article
- DOI
10.1007/s00425-003-1015-6