Hannink Nerissa K, Subramanian Murali, Rosser Susan J, Basran Amrik, Murray James A H, Shanks Jacqueline V, Bruce Neil C
Institute of Biotechnology, University of Cambridge, Cambridge, UK.
Int J Phytoremediation. 2007 Sep-Oct;9(5):385-401. doi: 10.1080/15226510701603916.
The manufacture, disposal, and detonation of explosives have resulted in the pollution of large tracts of land and groundwater. Historically, 2,4,6-trinitrotoluene (TNT) is the most widely used military explosive and is toxic to biological systems and recalcitrant to degradation. To examine the feasibility of enhancing the ability of plants to detoxify the explosive TNT, we created transgenic tobacco (Nicotiana tabacum) constitutively expressing the nsfI nitroreductase gene from Enterobacter cloacae. The product of TNT reduction by the nitroreductase was found to be 4-hydroxylamino-2,6-dinitrotoluene (4-HADNT). Characterization of the transgenic lines in sterile, aqueous conditions amended with TNT demonstrated that these plants were able to remove all of the TNT from the medium at an initial concentration of 0.5 mM (113 mg L(-1)) TNT. In contrast, growth was suppressed in wild-type plants at 0.1 mM (23 mg L(-1)). Following uptake, transgenic seedlings transformed TNT predominantly to 4-HADNT and its high levels appeared to correlate with enhanced tolerance and transformation of TNT. Transformation products of TNT were subsequently conjugated to plant macromolecules to a greater degree in transgenic tobacco, indicating enhanced detoxification compared to the wild type.
炸药的制造、处理及引爆已导致大片土地和地下水受到污染。从历史上看，2,4,6-三硝基甲苯（TNT）是使用最广泛的军用炸药，对生物系统有毒且难降解。为研究增强植物对炸药TNT解毒能力的可行性，我们培育了组成型表达来自阴沟肠杆菌的nsfI硝基还原酶基因的转基因烟草（烟草）。发现硝基还原酶还原TNT的产物是4-羟基氨基-2,6-二硝基甲苯（4-HADNT）。在用TNT改良的无菌水条件下对转基因株系进行表征表明，这些植物能够从初始浓度为0.5 mM（113 mg L(-1)）TNT的培养基中去除所有TNT。相比之下，野生型植物在0.1 mM（23 mg L(-1)）时生长受到抑制。吸收后，转基因幼苗将TNT主要转化为4-HADNT，其高水平似乎与TNT耐受性和转化增强相关。与野生型相比，TNT的转化产物随后在转基因烟草中与植物大分子的结合程度更高，表明解毒能力增强。
