Cloning And Genetic Transformation Of ε-LCY, Encoding Key Enzyme In Phytoxanthin Biosynthsis Pathway In Wheat(Triticum Aestivum L.)

Wheat is the world’s second largest food crop, and improving the nutritional quality of wheat is one of the important issues in wheat breeding. Carotenoids is one kind of indispensable components in the human diet, and different carotenoids on human health have different physiological roles. Because human and animal body can not synthesize carotenoids and must rely on daily food supply, while the content of carotenoids in wheat is relatively low (4μg/g or less), therefore, how to increase carotenoid content in wheat is especially important.Lutein plays an important role on human health, which constitutes the human retinal macular pigments. The human eye contains high levels of lutein, and this compound must be supplemented by intake because our human body can not synthesize it. Lutein deficiency will result in blindness. Besides, lutein is antioxidant and helps to prevent aging induced cardiovascular disease, coronary heart disease and cancer diseases. It is non-toxic, has excellent physiological effect, and is often used as a kind of food additive.Based on the genes encoding key enzyme ε-LCY in phytoxanthin biosynthsis pathway in wheat (GenBank number:EU649786.1), a1,611bp-long cDNA sequence containing the complete ORF of ε-LCY was cloned using total RNA isolated from leaves of wheat seedlings as template by RT-PCR approach. It encoded a protein with536amino acid residues. The ε-LCYoverexpression vector pAHC25-ε-LCY was constructed by inserting the ORF of ε-LCY between Ubi promoter and Nos terminator in pAHC25plasmid. This vector was then transferred in wheat by particle bombardment transformation. Sixteen PCR-positive lines of transgenic wheat were confirmed by PCR.The transgenic wheat lines overexpressing ε-LCY gene laid the foundation of wheat nutritional quality improvement through genetic engineering.