过表达水稻OsAQP增强转基因拟南芥耐盐性

水稻OsAQP是实验室前期从cDNA文库中筛选的功能未知的水通道蛋白质编码基因。本文采用DNA重组技术构建其植物过表达载体，并对拟南芥进行了遗传转化，筛选获得转基因拟南芥。采用50、100、125和150 mmol/L梯度盐胁迫处理，结果显示，转基因拟南芥的发芽率、根长以及鲜重分别比对照至少高17%、40.8%和14.29%，且差异达到显著水平（P<0.05）。在正常条件下，转基因植株叶片中抗坏血酸过氧化物酶(APX)活性显著高于WT；经300 mmol/L NaCl处理，转基因拟南芥叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)、APX酶活性均升高，与处理前相比分别提高7.37倍、30.87倍和1.77倍，且与WT的酶活性差异达到显著水平（P<0.05）；丙二醛(MDA)含量也在处理后上升，但在转基因植株中的含量低于WT，分别是WT的0.74倍、0.68倍和0.62倍，差异同样达到显著水平（P<0.05）。本研究提示，OsAQP过表达不仅能够促进拟南芥种子萌发和根系生长，而且在盐胁迫下通过提高拟南芥内源抗氧化酶活性、降低膜脂过氧化程度，增强了转基因植株对一定程度盐胁迫的耐受性。

Overexpression of Rice OsAQP Enhances Salt Tolerance of Transgenic Arabidopsis Thaliana

Aquaporin-encoding gene OsAQP was isolated from rice cDNA library with unidentified functions. In this article, the plant over-expression vector was constructed by DNA recombination technology, and then transformed into Arabidopsis thaliana. After treatment of gradient salt stress (50, 100, 125 and 150 mmol/L), the germination rate, root length and fresh weight of transgenic Arabidopsis were at least 17%, 40.8% and 14.29% significantly higher than those of the control respectively (P<0.05). Under normal conditions, APX activity in leaves of transgenic plants was significantly higher than that of WT. After treatment of 300 mmol/L NaCl, the activities of SOD, POD and APX in the leaves of transgenic Arabidopsis increased by at least 7.37 times, 30.87 times and 1.77 times, respectively, as compared with those before treatment, and the difference of the activities of SOD, POD and APX with control reached a significant level (P<0.05). Furthermore, the content of MDA was also increased, but the content of MDA in transgenic plants was significantly lower than that of WT, which was 0.74, 0.68 and 0.62 times of WT, respectively (P<0.05). This study suggests that ectopic over-expression of OsAQP can not only promote the seed germination and root growth of transgenic Arabidopsis, but also enhance the tolerance of transgenic plant to salt stress by increasing the activities of endogenous antioxidant enzymes and reducing the degree of membrane lipid peroxidation.