title: Low temperature and light regulate delta 12 fatty acid desaturases (FAD2) at a transcriptional level in cotton (Gossypium hirsutum).
abstract: Lipid modifying enzymes play a key role in the development of cold stress tolerance in cold-resistant plants such as cereals. However, little is known about the role of the endogenous enzymes in cold-sensitive species such as cotton. Delta 12 fatty acid desaturases (FAD2), known to participate in adaptation to low temperatures through acyl chain modifications were used in gene expression studies in order to identify parameters of plant response to low temperatures. The induction of microsomal delta 12 fatty acid desaturases at an mRNA level under cold stress in plants is shown here for first time. Quantitative PCR showed that though both delta 12 omega 6 fatty acid desaturase genes FAD2-3 and FAD2-4 identified in cotton are induced under cold stress, FAD2-4 induction is significantly higher than FAD2-3. The induction of both isoforms was light regulated, in contrast a third isoform FAD2-2 was not affected by cold or light. Stress tolerance and light regulatory elements were identified in the predicted promoters of both FAD2-3 and FAD2-4 genes. Di-unsaturated fatty acid species rapidly increased in the microsomal fraction isolated from cotton leaves, following cold stress. Expression analysis patterns were correlated with the observed increase in both total and microsomal fatty acid unsaturation levels suggesting the direct role of the FAD2 genes in membrane adaptation to cold stress.
authors.affiliation: Institute of Agrobiotechnology, Center for Research and Technology, 6th Km Charilaou, Thermi Road, 570 01 Thermi, Thessaloniki, Greece.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Kargiotidou
authors.forename: Dimitra
authors.initials: D
authors.lastname: Deli
authors.forename: Dia
authors.initials: D
authors.lastname: Galanopoulou
authors.forename: Athanasios
authors.initials: A
authors.lastname: Tsaftaris
authors.forename: Theodora
authors.initials: T
authors.lastname: Farmaki
mesh_terms: D000595:Amino Acid Sequence; D003080:Cold Temperature; D003624:Darkness; D044943:Fatty Acid Desaturases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D003368:Gossypium / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D008027:Light; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020218:Response Elements; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D013045:Species Specificity; D014158:Transcription, Genetic
chemical_list: D005227:Fatty Acids; D010940:Plant Proteins; D020033:Protein Isoforms; D044943:Fatty Acid Desaturases; C040448:delta-12 fatty acid desaturase