title: Non-redundant Contribution of the Plastidial FAD8 ω-3 Desaturase to Glycerolipid Unsaturation at Different Temperatures in Arabidopsis.
abstract: Plastidial ω-3 desaturase FAD7 is a major contributor to trienoic fatty acid biosynthesis in the leaves of Arabidopsis plants. However, the precise contribution of the other plastidial ω-3 desaturase, FAD8, is poorly understood. Fatty acid and lipid analysis of several ω-3 desaturase mutants, including two insertion lines of AtFAD7 and AtFAD8, showed that FAD8 partially compensated the disruption of the AtFAD7 gene at 22 °C, indicating that FAD8 was active at this growth temperature, contrasting to previous observations that circumscribed the FAD8 activity at low temperatures. Our data revealed that FAD8 had a higher selectivity for 18:2 acyl-lipid substrates and a higher preference for lipids other than galactolipids, particularly phosphatidylglycerol, at any of the temperatures studied. Differences in the mechanism controlling AtFAD7 and AtFAD8 gene expression at different temperatures were also detected. Confocal microscopy and biochemical analysis of FAD8-YFP over-expressing lines confirmed the chloroplast envelope localization of FAD8. Co-localization experiments suggested that FAD8 and FAD7 might be located in close vicinity in the envelope membrane. FAD8-YFP over-expressing lines showed a specific increase in 18:3 fatty acids at 22 °C. Together, these results indicate that the function of both plastidial ω-3 desaturases is coordinated in a non-redundant manner.
authors.affiliation: Estación Experimental de Aula Dei (EEAD-CSIC), Avda. Montañana 1005, 50059 Zaragoza, Spain; Instituto de la Grasa (IG-CSIC), Campus Universidad Pablo de Olavide, Building 46, Ctra. Utrera km. 1, 41013 Seville, Spain.
authors.forename: Ángela
authors.initials: Á
authors.lastname: Román
authors.affiliation: Instituto de la Grasa (IG-CSIC), Campus Universidad Pablo de Olavide, Building 46, Ctra. Utrera km. 1, 41013 Seville, Spain.
authors.forename: María L
authors.initials: ML
authors.lastname: Hernández
authors.affiliation: Estación Experimental de Aula Dei (EEAD-CSIC), Avda. Montañana 1005, 50059 Zaragoza, Spain.
authors.forename: Ángel
authors.initials: Á
authors.lastname: Soria-García
authors.affiliation: Estación Experimental de Aula Dei (EEAD-CSIC), Avda. Montañana 1005, 50059 Zaragoza, Spain.
authors.forename: Sara
authors.initials: S
authors.lastname: López-Gomollón
authors.affiliation: Estación Experimental de Aula Dei (EEAD-CSIC), Avda. Montañana 1005, 50059 Zaragoza, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Lagunas
authors.affiliation: Estación Experimental de Aula Dei (EEAD-CSIC), Avda. Montañana 1005, 50059 Zaragoza, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Picorel
authors.affiliation: Instituto de la Grasa (IG-CSIC), Campus Universidad Pablo de Olavide, Building 46, Ctra. Utrera km. 1, 41013 Seville, Spain.
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Martínez-Rivas
authors.affiliation: Estación Experimental de Aula Dei (EEAD-CSIC), Avda. Montañana 1005, 50059 Zaragoza, Spain. Electronic address: alfonso@eead.csic.es.
authors.forename: Miguel
authors.initials: M
authors.lastname: Alfonso
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D044943:Fatty Acid Desaturases / Q000235:genetics* / Q000378:metabolism; D038983:Galactolipids / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005989:Glycerides / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism; D030821:Plants, Genetically Modified; D018087:Plastids / Q000378:metabolism; D013696:Temperature
chemical_list: D029681:Arabidopsis Proteins; D038983:Galactolipids; D005989:Glycerides; D010743:Phospholipids; C000611285:FAD8 protein, Arabidopsis; D044943:Fatty Acid Desaturases; C084083:Fad7 protein, Arabidopsis
keywords: Arabidopsis thaliana; FAD7; FAD8; fatty acid; glycerolipid; plastid