转番茄正义抗坏血酸过氧化物酶基因提高烟草耐盐能力

 【目的】探讨叶绿体类囊体膜抗坏血酸过氧化物酶（tAPX）与耐盐性的关系。【方法】从番茄叶片中分离到类囊体膜抗坏血酸过氧化物酶基因（LetAPX），利用农杆菌介导的叶盘法转入到烟草中。Northern 杂交分析了LetAPX在盐胁迫（NaCl）下的表达特征。以野生型（WT），转正义LetAPX烟草株系T2-2（+）和T2-6（+）为试材，测定了盐胁迫条件下APX酶活性，过氧化氢（H2O2）含量，种子发芽率，植株的鲜重、干重，光合速率及叶绿素荧光参数。【结果】Northern杂交显示LetAPX已转到烟草基因组中，且基因的表达受盐胁迫的诱导。盐胁迫下转基因烟草的种子发芽率，植株的鲜重与干重，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净光合速率（Pn）和PSII最大光化学效率（Fv/Fm）。【结论】LetAPX的过量表达有助于提高烟草的耐盐能力。

Tobacco Plants Transformed with Tomato Sense LetAPX Enhanced Sair Tolerance

【Objective】 The objective is to investigate the relationship between thylakoid-bound ascorbate peroxidase (tAPX) and the salt tolerance. 【Method】 WT, sense-transgenic lines T2-2 (+) and T2-6 (+) of tobacco were used to measure the activities of APX and the content of hydrogen peroxide (H2O2), germination of seeds, photosynthetic rate and chorophyll fluorescence parameters under salt stress. 【Result】 Northern blot analysis confirmed that tomato thylakoid-bound ascorbate peroxidase gene (LetAPX) was transferred into the tobacco genome and the expression of LetAPX was induced by salt tolerance. Activities of APX and the capability for scavenging H2O2 of the transgenic tobacco plants were distinctly higher than those of WT under NaCl treatment. Overexpression of LetAPX in tobacco improved germination of seeds, fresh weight and dry weight of seedlings under salt stress. The photosynthetic rate and maximal photochemistry efficiency of PSII (Fv/Fm) in the transgenic plants were higher than those of WT after NaCl treatment. 【Conclusion】 These results indicate that the overexpression of LetAPX improved salt tolerance in transgenic tobacco plants.