Analysis of full-length cDNA sequence of FAD2 gene in Vernicia fordii seeds

Linoleic acid produced in seeds of Vernicia fordii is the direct material for synthesize eleostearic acid through catalysis of FAD2,the researches on FAD2 gene in seed from V.fordii has practical significance on improving yield of eleostearic acid.Taking 16 FAD2 clones in cDNA library of nearly mature V.fordii 'Duinian tung' seeds as materials,CAP3 splicing,BLAST alignment and DNAMAN analysis were carried on.The results showed that the cloned gene sequence was FAD2 full-length cDNA sequence,its length was 1 537 bp.The sequence contained a complete coding sequence,length of 1 146 bp(106-1 255 bp),encoding 383 amino acids.The relative molecular mass of the enzyme protein was 44 144.4 u,isoelectric point was 8.57.The N end of amino acid sequence had a signal peptide sequence of 6 residues,5 transmembrane domains,3 strong hydrophilic sequences existed at the N end,C end and intermediate part,respectively,and the activity center of enzyme was 3 conserved histidine clusters.In system evolution,FAD2 gene in V.fordii had a nearest phylogenetic relationship with V.montana,nearer relationship with Euphorbiaceae plants such as Ricinus communis,Triadica sebifrea,Hevea brasiliensis,Jatropha curcas,and far relationship with Olea europaea,Arachis hypogaea,Sesamum indicum,further relationship with Camelia oleifera.