Novel seed lipid phenotypes in combinations of mutants altered in fatty acid biosynthesis inArabidopsis.

The seed fatty acid (FA) composition of various single mutant combinations ofArabidopsis thaliana that affect FA biosynthesis has been examined. Double mutant combinations offae, a mutation affecting CIS elongation, and a series of four other FA biosynthetic mutants were synthesized. The four other single mutants were:fad2 andfad3, which are deficient in 18∶1 and 18∶2 desaturation, respectively;fab1, which is elevated in 16∶0 and decreased in 18∶1; andfab2, which is elevated in 18∶0 and decreased in 18∶1. The superimposition of two blocks in the FA biosynthetic pathway leads to dramatic changes in the FA content of the double mutants. The tenArabidopsis stocks analyzed to date (wild-type, five single mutants, and four double mutants) make seed oils with a wide range of FA compositions, and illustrate the diversity of oils it is possible to obtain from a single plant species.