title: Omega-3 fatty acid desaturase genes isolated from purslane (Portulaca oleracea L.): expression in different tissues and response to cold and wound stress.
abstract: Two full-length cDNA clones PoleFAD7 and PoleFAD8, encoding plastidial omega-3 fatty acid desaturases were isolated from purslane (Portulaca oleracea). The encoded enzymes convert linoleic to alpha-linolenic acid (C18:3n-3). Three histidine clusters characteristic of fatty acid desaturases, a putative chloroplast transit peptide in the N-terminal, and three putative transmembrane domains were identified in the sequence. Both genes were expressed in all analyzed tissues showing different levels of expression. PoleFAD7 was up-regulated by wounding but not by low temperature. PoleFAD8 was up-regulated by cold stress but not by wounding. Total fatty acid and linolenic acid content were higher both, in wounded and intact leaves of plants exposed to low temperature.
authors.affiliation: University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
authors.forename: Monica C
authors.initials: MC
authors.lastname: Teixeira
authors.forename: Isabel S
authors.initials: IS
authors.lastname: Carvalho
authors.forename: Maria
authors.initials: M
authors.lastname: Brodelius
mesh_terms: D003080:Cold Temperature; D044943:Fatty Acid Desaturases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D031822:Portulaca / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D017434:Protein Structure, Tertiary; D013312:Stress, Physiological
chemical_list: D010940:Plant Proteins; D044943:Fatty Acid Desaturases; C078565:omega-3 fatty acid desaturase