title: Genome Wide Analysis of Fatty Acid Desaturation and Its Response to Temperature.
abstract: Plants modify the polyunsaturated fatty acid content of their membrane and storage lipids in order to adapt to changes in temperature. In developing seeds, this response is largely controlled by the activities of the microsomal ω-6 and ω-3 fatty acid desaturases, FAD2 and FAD3. Although temperature regulation of desaturation has been studied at the molecular and biochemical levels, the genetic control of this trait is poorly understood. Here, we have characterized the response of Arabidopsis (Arabidopsis thaliana) seed lipids to variation in ambient temperature and found that heat inhibits both ω-6 and ω-3 desaturation in phosphatidylcholine, leading to a proportional change in triacylglycerol composition. Analysis of the 19 parental accessions of the multiparent advanced generation intercross (MAGIC) population showed that significant natural variation exists in the temperature responsiveness of ω-6 desaturation. A combination of quantitative trait locus (QTL) analysis and genome-wide association studies (GWAS) using the MAGIC population suggests that ω-6 desaturation is largely controlled by cis-acting sequence variants in theFAD25' untranslated region intron that determine the expression level of the gene. However, the temperature responsiveness of ω-6 desaturation is controlled by a separate QTL on chromosome 2. The identity of this locus is unknown, but genome-wide association studies identified potentially causal sequence variants within ∼40 genes in an ∼450-kb region of the QTL.
authors.affiliation: Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom (G.N.M., J.M.M., F.M.B., O.M.-A., K.H.-P., S.K., P.J.E.); and.|School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom (A.A.K.).
authors.forename: Guillaume N
authors.initials: GN
authors.lastname: Menard
authors.affiliation: Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom (G.N.M., J.M.M., F.M.B., O.M.-A., K.H.-P., S.K., P.J.E.); and.|School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom (A.A.K.).
authors.forename: Jose Martin
authors.initials: JM
authors.lastname: Moreno
authors.affiliation: Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom (G.N.M., J.M.M., F.M.B., O.M.-A., K.H.-P., S.K., P.J.E.); and.|School 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 (G.N.M., J.M.M., F.M.B., O.M.-A., K.H.-P., S.K., P.J.E.); and.|School 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 (G.N.M., J.M.M., F.M.B., O.M.-A., K.H.-P., S.K., P.J.E.); and.|School 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 (G.N.M., J.M.M., F.M.B., O.M.-A., K.H.-P., S.K., P.J.E.); and.|School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom (A.A.K.).
authors.forename: Keywan
authors.initials: K
authors.lastname: Hassani-Pak
authors.affiliation: Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom (G.N.M., J.M.M., F.M.B., O.M.-A., K.H.-P., S.K., P.J.E.); and.|School 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 (G.N.M., J.M.M., F.M.B., O.M.-A., K.H.-P., S.K., P.J.E.); and peter.eastmond@rothamsted.ac.uk.|School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom (A.A.K.) peter.eastmond@rothamsted.ac.uk.
authors.forename: Peter J
authors.identifier: 0000-0003-4526-5136
authors.initials: PJ
authors.lastname: Eastmond
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D044943:Fatty Acid Desaturases / Q000235:genetics / Q000378:metabolism; D015525:Fatty Acids, Omega-3 / Q000096:biosynthesis*; D043371:Fatty Acids, Omega-6 / Q000096:biosynthesis*; D018506:Gene Expression Regulation, Plant; D055106:Genome-Wide Association Study / Q000379:methods*; D008055:Lipids / Q000032:analysis; D010713:Phosphatidylcholines / Q000032:analysis / Q000378:metabolism; D030821:Plants, Genetically Modified; D040641:Quantitative Trait Loci / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D013696:Temperature; D014280:Triglycerides / Q000032:analysis / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D008055:Lipids; D010713:Phosphatidylcholines; D014280:Triglycerides; D044943:Fatty Acid Desaturases; C523310:FAD2 protein, Arabidopsis; C474651:fad3 protein, Arabidopsis