Abstract：
Symbiosis between Glycine max and Bradyrhizobium diazoefficiens were used as a model system to investigate whether biohydrogen utilization promotes the transformation of the tetrachlorobiphenyl PCB77. Both a H2 uptake-positive (Hup+) strain (wild type) and a Hup- strain (a hupL deletion mutant) were inoculated into soybean nodules. Compared with Hup- nodules, Hup+ nodules increased dechlorination significantly by 61.1 % and reduced the accumulation of PCB77 in nodules by 37.7 % (p < 0.05). After exposure to nickel, an enhancer of uptake hydrogenase, dechlorination increased significantly by 2.2-fold, and the accumulation of PCB77 in nodules decreased by 54.4 % (p < 0.05). Furthermore, the tetrachlorobiphenyl transformation in the soybean root nodules was mainly testified to be mediated by nitrate reductase (encoded by the gene NR) for tetrachlorobiphenyl dechlorination and biphenyl-2,3-diol 1,2-dioxygenase (bphC) for biphenyl degradation. This study demonstrates for the first time that biohydrogen utilization has a beneficial effect on tetrachlorobiphenyl biotransformation in a legume-rhizobium symbiosis.
摘要：
甘氨酸max与缓生根瘤菌重氮二氮杂之间的共生关系被用作模型系统，以研究生物氢的利用是否促进了四氯联苯PCB77的转化。将H2摄取阳性(Hup+)菌株(野生型)和Hup-菌株(hupL缺失突变体)接种到大豆结节中。与Hup结节相比，Hup+结节显著增加脱氯61.1%，减少结节中PCB77的积累37.7%(p<0.05)。接触镍后，氢化酶的摄取增强剂，脱氯率显著增加了2.2倍，结核中PCB77的积累减少了54.4%(p<0.05)。此外，大豆根瘤中的四氯联苯转化主要是由硝酸还原酶（由基因NR编码）介导的四氯联苯脱氯和联苯-2,3-二醇1,2-双加氧酶（bphC）介导的联苯降解。这项研究首次表明，生物氢的利用对豆科植物-根瘤菌共生中的四氯联苯生物转化具有有益的影响。
