title: bZIP67 regulates the omega-3 fatty acid content of Arabidopsis seed oil by activating fatty acid desaturase3.
abstract: Arabidopsis thaliana seed maturation is accompanied by the deposition of storage oil, rich in the essential ω-3 polyunsaturated fatty acid α-linolenic acid (ALA). The synthesis of ALA is highly responsive to the level of fatty acid desaturase3 (FAD3) expression, which is strongly upregulated during embryogenesis. By screening mutants in leafy cotyledon1 (LEC1)-inducible transcription factors using fatty acid profiling, we identified two mutants (lec1-like and bzip67) with a seed lipid phenotype. Both mutants share a substantial reduction in seed ALA content. Using a combination of in vivo and in vitro assays, we show that bZIP67 binds G-boxes in the FAD3 promoter and enhances FAD3 expression but that activation is conditional on bZIP67 association with LEC1-like (L1L) and nuclear factor-YC2 (NF-YC2). Although FUSCA3 and abscisic acid insensitive3 are required for L1L and bZIP67 expression, neither protein is necessary for [bZIP67:L1L:NF-YC2] to activate FAD3. We conclude that a transcriptional complex containing L1L, NF-YC2, and bZIP67 is induced by LEC1 during embryogenesis and specifies high levels of ALA production for storage oil by activating FAD3 expression.
authors.affiliation: School of Life Sciences, University of Warwick, Warwickshire CV35 9EF, United Kingdom.
authors.forename: Ana
authors.initials: A
authors.lastname: Mendes
authors.forename: Amélie A
authors.initials: AA
authors.lastname: Kelly
authors.forename: Harrie
authors.initials: H
authors.lastname: van Erp
authors.forename: Eve
authors.initials: E
authors.lastname: Shaw
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Powers
authors.forename: Smita
authors.initials: S
authors.lastname: Kurup
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Eastmond
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D004789:Enzyme Activation; D044943:Fatty Acid Desaturases / Q000235:genetics / Q000378:metabolism*; D015525:Fatty Acids, Omega-3 / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D009929:Organ Size; D010713:Phosphatidylcholines / Q000378:metabolism; D010938:Plant Oils / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding / Q000235:genetics; D055314:Seed Storage Proteins / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation / Q000235:genetics; D014280:Triglycerides / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D004269:DNA, Bacterial; D015525:Fatty Acids, Omega-3; D010713:Phosphatidylcholines; D010938:Plant Oils; D055314:Seed Storage Proteins; C036483:T-DNA; D014280:Triglycerides; C587936:bZIP67 protein, Arabidopsis; D044943:Fatty Acid Desaturases; C474651:fad3 protein, Arabidopsis