Abstract

Vitamin E is a group of lipid soluble compounds, which are important antioxidants and play a crucial role in mammals and plants. They can protect the membrane from photooxidation, and they are involved in signal transduction and transcription regulation as well. The enzyme homogentisate phytyltransferase (HPT) has been demonstrated to be a key enzyme limiting tocopherol biosynthesis. In this study,HPT gene isolated from Lactuca sativa L. (LsHPT) was transferred into L. sativa(lettuce) via Agrobacterium-mediated method and 15 transgenic plants were obtained. The expression of LsHPT gene and the total content of α and γ-tocopherol in transgenic plants were increased up to 4 and 2.61 folds, respectively, demonstrating that overexpression of HPT gene is an effective way to improve vitamin E content in lettuce.

Key words: Lactuca sativa, tocopherol, homogentisate phytyltransferase (HPT),Agrobacterium-mediated transformation, real-time fluorescent quantitative-polymerase chain reaction (qRT-PCR).

Abbreviation

DRI, Dietary reference intake; FW, fresh weight; GGDP,geranylgeranyl diphosphate; HGA, homogentisic acid; HPLC, high performance liquid chromatography; HPT, homogentisate phytyltransferase; MPBQ, 2-methyl-6-phytyl-1,4-benzoquinol; PDP, phytyl diphosphate; PFD, photon flux density; RACE,rapid amplification of cDNA ends; ROS, reactive oxygen species.