Cloning And Comparative Studies Of Genes Involved In Oil Content In Seed

Oil content is the key object of oilseed breeding. It is important to investigate the genes related to oil content. In this study, 5 genes involved in oil content during triacylglycerol biosynthesis were cloned or synthesized in order to elucidate through transgenic over-expression how different the 5 genes are on the oil content.To investigate the function of the genes involed in oil content, the full cDNA sequences of BnGPDH,BnGPAT and BnDGAT genes were cloned from rapeseed, as well as ScGPDH,ScLPAT were synthesized from yeast. These 5 sequences were aligned and analyzed by using bioinformatic tools and then incorporated into rapeseed and tobacco transgenic vectors regulated by Napin promoter. A lot of positive tobacco transformants of these genes were obtained through agrobacterium-mediated transformation. The following results were drawn through the analysis of oil content in seed by gas chromatography.The results of wild type tobacco showed that the oil content of WT is 12.68% with the fatty acids C16:0, C18:0, C18:1, C18:2, C18:3 and free of long chain fatty acid. The T0 transformants of tabacco showed significantly higher oil content in seed than WT tobacco when transformed separately with BnDGAT and ScLPAT gene and showed highly significant higher oil content in seed when transformed separately with BnGPAT, ScGPDH and BnGPDH gene.In T1 generation, all the transformants from the four genes BnGPAT, BnDGAT, ScGPDH and ScLPAT showed significantly higher oil content with the rang 14.26%-18.03%, 13.93%-18.88%, 14.18%-19.58% and 13.80%-20.64%, and the mean 15.91%, 16.05%, 16.50% and 16.93%, respectively, corresponding to an oil content increase by 25.47%,26.58%,30.13% and 33.52%. Transformants from BnGPDH showed larger variation in oil content ranging from 11.73% to 19.85%, among which only one transformant showed a 7.51% drop in oil content.In conclusion, all the 5 genes derived from rapeseed and yeast can increase seed oil content significantly and they ranked from ScLPAT, ScGPDH, BnGPDH, BnDGAT to BnGPAT according to the magnitude of the increase in oil content. This study provides a basis for the further experiment by stacking these genes into a single rapeseed cultivar.