PLANT PHYSIOLOGY , Vol 114, Issue 4 1533-1539, Copyright © 1997 by American Society of Plant Biologists
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BIOCHEMISTRY AND ENZYMOLOGY |
Overexpression of the FAD3 Desaturase Gene in a Mutant of Arabidopsis
S. Shah, Z. Xin and J. Browse
Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
A mutant of Arabidopsis contained increased levels of 18:3 fatty acids and
correspondingly decreased levels of 18:2. The fatty acid phenotype was
strongly expressed in root and seed tissues and this observation, together
with other data, suggested that the mutation leads to increased activity of
the endoplasmic reticulum 18:2 desaturase encoded by the FAD3 gene.
Gel-blot analysis of RNA from wild-type and mutant plants established that
FAD3 transcript levels were increased 80% in the mutant relative to the
wild type. Genetic analysis demonstrated a linkage between the new mutation
and the fad3 locus. Linkage of the mutation to fad3 raises the possibility
that the lesion is an alteration to the promoter or another regulatory
region of the FAD3 gene, which results in increased transcription.
