Gene Cloning And Plant Expression Vector Construction Of Apple Ascorbate Peroxidase Gene

The growth and development process of the plant was frequently influenced by environmental factors. When the plant was undergoing some adverse circumstances such as the high temperature, the droughts stress and so on, plants reactive oxygen system was triggered and reactive oxygen species were accumulated. Ascorbate peroxidase is the critical enzyme of scavenging the reactive oxygen species, which act to limit the effects of H₂O₂ generated during normal plant development, and protect chloroplast and other cellular components against oxidative injury. When the reactive oxygen species accumulated, the APX expression and detoxification of H₂O₂ through reaction of ascorbate and H₂O₂ can be immediately induced. So far this is the first report of the full length APX gene from apple.In this study, a full length ascorbate peroxidase gene was cloned from apple leaf and a plant expression vector was constructed. Further information about APX gene functions in AsA-GSH cycle and its metabolism pathway will be investigated by gene transformation. Main results of this study were as follows:1. SDS-Hot Hydro-xybenzene method was adopted to extract RNA from apple leaves, which has laid the base for the following experiment.2. Based on submitted APX sequences from other plants, first we get a APX fragment from apple, then we get the full length APX cDNA sequence by using 3'-RACE and 5'-RACE. The largest ORF encodes 250 amino acids. Apple APX gene showed high identity with other plants respectively.3. The plant expression vector pUAm+pSB166-APX was constructed.