Responses of Antioxidant Enzyme and PSII Electron Transport in Leaf of Transgenic Tobacco Carrying 2-Cys Prx to Salt and Light Stresses

Abstract

2-Cys Peroxiredoxins(2-Cys Prxs)in plants were reported to localize to plant chloroplasts and perform antioxidative function during plant development and photosynthesis.This paper investigated the function of tobacco 2-Cys Prx gene overexpressed in transgenic tobacco(Nicotiana tabacum)plants with tolerance against light intensity and salt stresses.The results showed that superoxide dismutase(SOD)activity in leaves of two types of tobacco increased under weak light(200 μmol m–2s–1)and salt stresses,ascorbateperoxidase(APX)activity changed little,and the content of H2O2slightly increased.Salt stress enhanced SOD activity and decreased APX activity under strong light(1000 μmol m–2s–1).The content of H2O2in leaves of transgenic tobacco with 2-Cys Prx increased slower than that of wild tobacco.The electron transport rate(ETR),PSII photochemical efficiency(Fv/Fm)and actual photochemical efficiency( PSII)in leaves of transgenic tobacco with 2-Cys Prx were higher than those of control under high light.Electron transports in the receptor side were lower than that in control.The results suggested that2-Cys Prx could be the effective removal of excess H2O2while APX activity decreased under high light and salt stresses,and could reduce PSII photoinhibition induced by high light and salt stresses.