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为了探讨叶绿体类囊体膜抗坏血酸过氧化物酶(tAPX)与其抗氧化性的关系,从番茄叶片中分离了叶绿体类囊体膜抗坏血酸过氧化物酶基因(StAPX)并转入到烟草中。以野生型(WT)、转正义StAPX烟草株系T3-3和T3-6为试材,测定了外源过氧化氢诱导的氧化胁迫条件下APX酶活性、过氧化氢酶(CAT)活性、过氧化氢(H2O2)含量、叶绿素荧光参数及叶绿素含量等。Northern杂交显示StAPX基因的表达受外源H2O2氧化胁迫的诱导。氧化胁迫下转基因烟草的APX酶活性和清除H2O2的能力都显著高于野生型,并且转基因烟草比野生型具有更高的PSII最大光化学效率及叶绿素含量。结果表明,StAPX的过量表达有助于提高外源H2O2诱导的转基因烟草的抗氧化能力。
In order to investigate the relationship between the chloroplast thylakoid membrane ascorbate peroxidase (tAPX) and its antioxidant activity, the chloroplast thylakoid membrane ascorbate peroxidase gene (StAPX) was isolated from tomato leaves and transferred into tobacco. The wild-type (WT) and T3 transgenic tobacco lines T3-6 and T3-6 were used as materials to measure the activity of APX, catalase (CAT) under the condition of oxidative stress induced by exogenous hydrogen peroxide, Hydrogen peroxide (H2O2) content, chlorophyll fluorescence parameters and chlorophyll content. Northern blotting showed that StAPX gene expression was induced by exogenous H2O2 oxidative stress. The oxidase-induced APXase activity and H2O2-clearing ability of transgenic tobacco were significantly higher than wild type, and transgenic tobacco had higher PSII maximum photochemical efficiency and chlorophyll content than wild type. The results showed that overexpression of StAPX could enhance the antioxidant capacity of exogenous H2O2-induced transgenic tobacco.