Bioremediation of 2,4,6-trinitrotoluene by bacterial nitroreductase expressing transgenic aspen
Bioremediation of 2,4,6-trinitrotoluene by bacterial nitroreductase expressing transgenic aspen
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DOI：
10.1021/es801231w
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发表时间：
2008-10-01
影响因子：
11.4
通讯作者：
Ramos, Juan L.
中科院分区：
文献类型：
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作者：
van Dillewijn, Pieter;Couselo, Jose L.;Ramos, Juan L.
杨属植物因其根系形成深、生长快、蒸腾速率高等特点，常被用于植物修复。在这里，我们研究了转基因杂交杨的生长能力。表达细菌硝基还原酶基因PNRA，以耐受并从受污染的水和土壤中吸收更多有毒和顽固的爆炸物2，4，6-三硝基甲苯(TNT)。在水培条件下，转基因杨树最高耐受量为57mgTNT/L，在土壤中耐受量超过1000mgTNT/kg，而亲本杨树则不能耐受高于11mgTNT/L的水培或高于500mgTNT/kg的土壤。同样，转基因植株对恒定浓度的TNT的植物毒性下限为20mgTNT/L，而野生型植株仅耐受10mgTNT/L。当TNT的初始浓度在液体介质中大于35mgTNT/L或在土壤中大于750mgTNT/kg时，转基因植株对TNT的吸收也高于野生植株。用C-13标记TNT的分析表明，TNT迅速吸附到根表面，然后进入植物的速率较慢，从标记TNT中被植物吸收的大部分C-13-碳(>；95%)仍然留在根中，很少转移到茎中。总之，表达PNRA的转基因杨树在污染土壤和地下含水层的植物修复应用中具有很高的兴趣。
Trees belonging to the genus Populus are often used for phytoremediation due to their deep root formation, fast growth and high transpiration rates. Here, we study the capacity of transgenic hybrid aspen (Populus tremula x tremuloides var. Etropole) which expresses the bacterial nitroreductase gene, pnrA, to tolerate and take-up greater amounts of the toxic and recalcitrant explosive, 2,4,6-trinitrotoluene (TNT) from contaminated waters and soil. Transgenic aspen tolerate up to 57 mg TNT/L in hydroponic media and more than 1000 mg TNT/kg soil,whereas the parental aspen could not endure in hydroponic culture with more than 11 mg TNT/L or soil with more than 500 mg TNT/kg. Likewise,the phytotoxicological limit for transgenic plants to a constant concentration of TNT was 20 mg TNT/L while wild-type plants only tolerated 10 mg TNT/L. Transgenic plants also showed improved uptake of TNT over wild-type plants when the original TNT concentration was above 35 mg TNT/L in liquid media or 750 mg TNT/kg in soil. Assays with C-13-labeled TNT show rapid adsorption of TNT to the root surface followed by a slower entrance rate into the plant Most of the C-13-carbon from the labeled TNT taken up by the plant (>95%) remains in the root with little translocation to the stem. Altogether, transgenic aspen expressing pnrA are highly interesting for phytoremediation applications on contaminated soil and underground aquifers.