title: Cloning and functional expression of a cDNA encoding stearoyl-ACP Δ9-desaturase from the endosperm of coconut (Cocos nucifera L.).
abstract: Coconut (Cocos nucifera L.) is an economically tropical fruit tree with special fatty acid compositions. The stearoyl-acyl carrier protein (ACP) desaturase (SAD) plays a key role in the properties of the majority of cellular glycerolipids. In this paper, a full-length cDNA of a stearoyl-acyl carrier protein desaturase, designated CocoFAD, was isolated from cDNA library prepared from the endosperm of coconut (C. nucifera L.). An 1176 bp cDNA from overlapped PCR products containing ORF encoding a 391-amino acid (aa) protein was obtained. The coded protein was virtually identical and shared the homology to other Δ9-desaturase plant sequences (greater than 80% as similarity to that of Elaeis guineensis Jacq). The real-time fluorescent quantitative PCR result indicated that the yield of CocoFAD was the highest in the endosperm of 8-month-old coconut and leaf, and the yield was reduced to 50% of the highest level in the endosperm of 15-month-old coconut. The coding region showed heterologous expression in strain INVSc1 of yeast (Saccharomyces cerevisiae). GC-MS analysis showed that the levels of palmitoleic acid (16:1) and oleic acid (18:1) were improved significantly; meanwhile stearic acid (18:0) was reduced. These results indicated that the plastidial Δ9 desaturase from the endosperm of coconut was involved in the biosynthesis of hexadecenoic acid and octadecenoic acid, which was similar with other plants. These results may be valuable for understanding the mechanism of fatty acid metabolism and the genetic improvement of CocoFAD gene in palm plants in the future.
authors.affiliation: Department of Biotechnology, Hainan University, Haikou, Hainan 570228, China.
authors.forename: Lingchao
authors.initials: L
authors.lastname: Gao
authors.affiliation: Department of Biotechnology, Hainan University, Haikou, Hainan 570228, China.
authors.forename: Ruhao
authors.initials: R
authors.lastname: Sun
authors.affiliation: Department of Biotechnology, Hainan University, Haikou, Hainan 570228, China.
authors.forename: Yuanxue
authors.initials: Y
authors.lastname: Liang
authors.affiliation: Department of Biotechnology, Hainan University, Haikou, Hainan 570228, China.
authors.forename: Mengdan
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Department of Biotechnology, Hainan University, Haikou, Hainan 570228, China. Electronic address: hainanzyh@hotmail.com.
authors.forename: Yusheng
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Biotechnology, Hainan University, Haikou, Hainan 570228, China; Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Hainan University, Haikou, Hainan 570228, China. Electronic address: liddfym@hotmail.com.
authors.forename: Dongdong
authors.initials: D
authors.lastname: Li
mesh_terms: D003001:Cloning, Molecular; D003059:Cocos / Q000196:embryology / Q000201:enzymology* / Q000235:genetics; D056625:Endosperm / Q000201:enzymology* / Q000235:genetics; D005229:Fatty Acids, Monounsaturated / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D006639:Histidine / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000235:genetics* / Q000378:metabolism*; D019301:Oleic Acid / Q000378:metabolism; D016366:Open Reading Frames; D010802:Phylogeny; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013229:Stearic Acids / Q000378:metabolism
chemical_list: D005229:Fatty Acids, Monounsaturated; D010940:Plant Proteins; D029701:Saccharomyces cerevisiae Proteins; D013229:Stearic Acids; C008757:palmitoleic acid; D019301:Oleic Acid; C031183:stearic acid; D006639:Histidine; D006899:Mixed Function Oxygenases; C018747:acyl-(acyl-carrier-protein)desaturase
keywords: Coconut (Cocos nucifera L.); Fatty acid desaturase; Function analysis; Saccharomyces cerevisiae