Abstract

Plants encounter many environmental factors such as low and high temperatures during phytoremediation processes. In this study, our aim was to produce the transgenic tobacco plants by using a newly characterized bacterial nitroreductase, Ntr, which was active at a broad range temperature in order to detoxify 2,4-dinitrotoluene (2,4-DNT) at lower temperature. The presence of Ntr and its heterologous expression was verified in T1 transgenic plants and their growing ability were determined under toxic amount of 2,4-DNT (35 µM). Fresh weight and dry weight of transgenic plants were significantly higher than wild type (WT) under toxic 2,4-DNT at 22 °C, indicating higher growth capacity of the transgenics. Transgenic plants also showed a higher tolerance than WT when exposed to 2,4-DNT at 15 °C. Moreover, transformation rate of 2,4-DNT was gradually decreased through decreasing temperatures in WT media, however, it was increased through decreasing temperatures in transgenic plant TR3-25 media and it had the highest transformation rate (54%) of 2,4-DNT at 4 °C. Correlatively, 2,4-DNT treatment at 4 °C led to a significant decrease in H₂O₂ level in transgenic plants. Thus, transgenic plants overexpressing nitroreductase might have an important advantage for phytoremediation of toxic nitroaromatic compounds in field applications at low temperatures.

 抽象的

植物在植物修复过程中会遇到许多环境因素，例如低温和高温。在这项研究中，我们的目标是通过使用新表征的细菌硝基还原酶Ntr来生产转基因烟草植物，该酶在较宽的温度范围内具有活性，以便在较低温度下解毒 2,4-二硝基甲苯 (2,4-DNT) 。在 T1 转基因植物中验证了Ntr的存在及其异源表达，并在有毒量的 2,4-DNT (35 µM) 下测定了它们的生长能力。在22℃有毒2,4-DNT条件下，转基因植物的鲜重和干重均显着高于野生型（WT），表明转基因植物具有更高的生长能力。当在 15 °C 下暴露于 2,4-DNT 时，转基因植物也表现出比 WT 更高的耐受性。此外，在WT培养基中，2,4-DNT的转化率随着温度的降低而逐渐降低，而在转基因植物TR3-25培养基中，2,4-DNT的转化率则随着温度的降低而增加，其中2,4-DNT的转化率最高(54%)。 -DNT，4°C。相应地，4°C 下的2,4-DNT 处理导致转基因植物中H ₂ O ₂水平显着降低。因此，过表达硝基还原酶的转基因植物可能对低温下田间有毒硝基芳香族化合物的植物修复具有重要优势。