title: ACYL-ACYL CARRIER PROTEIN DESATURASE2 and 3 Are Responsible for Making Omega-7 Fatty Acids in the Arabidopsis Aleurone.
abstract: Omega-7 monounsaturated fatty acids (ω-7s) are specifically enriched in the aleurone of Arabidopsis (Arabidopsis thaliana) seeds. We found significant natural variation in seed ω-7 content and used a Multiparent Advanced Generation Inter-Cross population to fine-map a major quantitative trait loci to a region containing ACYL-ACYL CARRIER PROTEIN DESATURASE1 (AAD1) and AAD3 We found that AAD3 expression is localized to the aleurone where mutants show an approximately 50% reduction in ω-7 content. By contrast, AAD1 is localized to the embryo where mutants show a small reduction in ω-9 content. Enzymatic analysis has previously shown that AAD family members possess both stearoyl- and palmitoyl-ACP Δ(9) desaturase activity, including the predominant isoform SUPPRESSOR OF SALICYLIC ACID INSENSITIVE2. However, aad3 ssi2 aleurone contained the same amount of ω-7s as aad3 Within the AAD family, AAD3 shares the highest degree of sequence similarity with AAD2 and AAD4. Mutant analysis showed that AAD2 also contributes to ω-7 production in the aleurone, and aad3 aad2 exhibits an approximately 85% reduction in ω-7s Mutant analysis also showed that FATTY ACID ELONGASE1 is required for the production of very long chain ω-7s in the aleurone. Together, these data provide genetic evidence that the ω-7 pathway proceeds via Δ(9) desaturation of palmitoyl-ACP followed by elongation of the product. Interestingly, significant variation was also identified in the ω-7 content of Brassica napus aleurone, with the highest level detected being approximately 47% of total fatty acids.
authors.affiliation: Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom (F.M.B., O.M.-A., F.B., S.K., P.J.E.); andSchool of Life Sciences, University of Warwick, Coventry, CV4 7AL, United Kingdom (A.A.K.).
authors.forename: Fiona M
authors.initials: FM
authors.lastname: Bryant
authors.affiliation: Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom (F.M.B., O.M.-A., F.B., S.K., P.J.E.); andSchool of Life Sciences, University of Warwick, Coventry, CV4 7AL, United Kingdom (A.A.K.).
authors.forename: Olaya
authors.initials: O
authors.lastname: Munoz-Azcarate
authors.affiliation: Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom (F.M.B., O.M.-A., F.B., S.K., P.J.E.); andSchool of Life Sciences, University of Warwick, Coventry, CV4 7AL, United Kingdom (A.A.K.).
authors.forename: Amélie A
authors.identifier: 0000-0003-2142-9327
authors.initials: AA
authors.lastname: Kelly
authors.affiliation: Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom (F.M.B., O.M.-A., F.B., S.K., P.J.E.); andSchool of Life Sciences, University of Warwick, Coventry, CV4 7AL, United Kingdom (A.A.K.).
authors.forename: Frédéric
authors.identifier: 0000-0001-9847-3866
authors.initials: F
authors.lastname: Beaudoin
authors.affiliation: Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom (F.M.B., O.M.-A., F.B., S.K., P.J.E.); andSchool of Life Sciences, University of Warwick, Coventry, CV4 7AL, United Kingdom (A.A.K.).
authors.forename: Smita
authors.initials: S
authors.lastname: Kurup
authors.affiliation: Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom (F.M.B., O.M.-A., F.B., S.K., P.J.E.); andSchool of Life Sciences, University of Warwick, Coventry, CV4 7AL, United Kingdom (A.A.K.) peter.eastmond@rothamsted.ac.uk.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Eastmond
mesh_terms: D000213:Acyl Carrier Protein / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D044943:Fatty Acid Desaturases / Q000235:genetics / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D030821:Plants, Genetically Modified; D040641:Quantitative Trait Loci / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000235:genetics / Q000378:metabolism*
chemical_list: D000213:Acyl Carrier Protein; D029681:Arabidopsis Proteins; D005231:Fatty Acids, Unsaturated; D007527:Isoenzymes; D044943:Fatty Acid Desaturases