Identification of a gene that complements an Arabidopsis mutant deficient in chloroplast omega 6 desaturase activity.

AUTOR(ES)

Falcone, D L

RESUMO

Membrane lipids of the fad6 (formerly fadC) mutant of Arabidopsis, which is deficient in chloroplast omega 6 desaturase activity, have increased levels of monounsaturated fatty acids and are deficient in trienoic fatty acids. A putative fad6 cDNA clone was isolated by probing a cDNA library with a degenerate oligonucleotide based on a conserved region within known omega 3 desaturase genes. Expression of the cDNA in transgenic plants of a fad6 mutant restored normal levels of all fatty acids. When used as a hybridization probe, the cDNA identified a restriction fragment-length polymorphism that co-segregated with the fad6 mutation. Thus, on the basis of a genetic complementation test and genetic map position, the fad6 gene is encoded by the cDNA. The cDNA encoded a 418-amino acid polypeptide of 47,727 D that displayed a high degree of sequence similarity to a delta 12 desaturase from the cyanobacterium Synechocystis. The fad6 gene exhibited less sequence homology to any known higher plant desaturase, including an endoplasmic reticulum-localized omega 6 desaturase corresponding to the Arabidopsis fad2 gene.

Documentos Relacionados

• Cloning of a temperature-regulated gene encoding a chloroplast omega-3 desaturase from Arabidopsis thaliana.
• A Mutation at the fad8 Locus of Arabidopsis Identifies a Second Chloroplast [omega]-3 Desaturase.
• Properties of an Escherichia coli mutant deficient in phosphoenolpyruvate carboxylase catalytic activity.
• Altered regulation of lipid biosynthesis in a mutant of Arabidopsis deficient in chloroplast glycerol-3-phosphate acyltransferase activity
• Overexpression of the FAD3 desaturase gene in a mutant of Arabidopsis.