Mutations in the fatty acid elongation 1 gene are associated with a loss of beta-ketoacyl-CoA synthase activity in low erucic acid rapeseed.
Low erucic acid rapeseed (LEAR) is characterised by a near absence of very long chain fatty acids in the seed oil which has been correlated with a lack of acyl-CoA elongation activity. Here we show that the absence of acyl-CoA and ATP-dependent elongation activities in microsomes isolated from LEAR embryos is associated with an absence of beta-ketoacyl-CoA synthase activity encoded by the Bn-fatty acid elongation 1 (FAE1) genes. Size exclusion chromatography of solubilised microsomes revealed the presence of a high molecular mass acyl-CoA elongase complex in high erucic acid rapeseed which was absent in microsomes isolated from LEAR seeds. Although transcripts for the Bn-FAE1 genes were detected in LEAR embryos, immunoblots using antisera raised against the beta-ketoacyl-CoA synthase indicated an absence of this protein. Comparison of the deduced amino acid sequences of immature embryo cDNAs reveals that LEAR alleles of Bn-FAE1 encode variant beta-ketoacyl-CoA synthase proteins.
Laboraoire de Génome et Développement des Plantes, CNRS UMR 5096, Université de Perpignan, France. roscoe@univ-perp.fr
T J
TJ
Roscoe
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R
Lessire
J
J
Puyaubert
M
M
Renard
M
M
Delseny
D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase / Q000378:metabolism*; D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001937:Brassica / Q000201:enzymology* / Q000378:metabolism; D002850:Chromatography, Gel; D018076:DNA, Complementary / Q000032:analysis; D004883:Erucic Acids / Q000378:metabolism*; D000081031:Fatty Acid Elongases; D014644:Genetic Variation; D007118:Immunoassay; D008969:Molecular Sequence Data; D009154:Mutation; D017386:Sequence Homology, Amino Acid; D012995:Solubility
D018076:DNA, Complementary; D004883:Erucic Acids; C049811:erucic acid; D000123:Acetyltransferases; D000081031:Fatty Acid Elongases; D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase