College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture, Nanjing, 210095, PR China.
College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture, Nanjing, 210095, PR China; College of Agricultural Engineering, Nanyang Normal University, Nanyang, 473061, PR China.
Ecotoxicol Environ Saf. 2020 Oct 15;203:111017. doi: 10.1016/j.ecoenv.2020.111017. Epub 2020 Jul 14.
In this study, the effect of two metal-immobilizing bacterial strains, Serratia liquefaciens CL-1 and Bacillus thuringiensis X30, on the availability of Cd and Pb and the metal accumulation in potato tubers, as well as the underlying mechanisms in metal-contaminated soils were characterized. Moreover, the impacts of the strains on metal immobilization, pH, and NH concentration in metal-contaminated soil solutions were evaluated. Strains CL-1 and X30 increased tuber dry weight by 46% and 40%, reduced tuber Cd and Pb contents by 68-83% and 42-47%, and decreased the Cd and Pb translocation factors by 61-70% and 30-34%, respectively, compared to the controls. Strains CL-1 and X30 decreased the available Cd and Pb contents by 52-67% and 30-44% and increased the NH content by 55% and 31%, pH, urease activity by 70% and 41%, and relative abundance of ureC gene copies by 37% and 20% in the rhizosphere soils, respectively, compared with the controls. Reduced Cd and Pb concentrations and increased pH and NH concentration were found in the bacteria-inoculated soil solution compared to the controls. These results suggested that the strains reduced tuber metal uptake through decreasing the metal availability and increasing the pH, ureC gene relative abundance and urease activity as well as decreasing the metal translocation from the leaves to tubers. These results may provide an effective metal-immobilizing bacteria (especially strain CL-1)-enhanced approach to reduce metal uptake of potato tubers in metal-polluted soils.
在这项研究中，研究了两种金属固定化细菌菌株——液化沙雷氏菌 CL-1 和苏云金芽孢杆菌 X30 对土壤中 Cd 和 Pb 的有效性、在马铃薯块茎中的积累以及金属污染土壤中潜在机制的影响。此外，还评估了菌株对金属固定、pH 值和金属污染土壤溶液中 NH 浓度的影响。与对照相比，菌株 CL-1 和 X30 分别使块茎干重增加了 46%和 40%，使块茎 Cd 和 Pb 含量降低了 68-83%和 42-47%，使 Cd 和 Pb 转移系数降低了 61-70%和 30-34%。菌株 CL-1 和 X30 分别使有效态 Cd 和 Pb 含量降低了 52-67%和 30-44%，使 NH 含量增加了 55%和 31%，使 pH 值、脲酶活性分别增加了 70%和 41%，使根际土壤中 ureC 基因拷贝数相对丰度分别增加了 37%和 20%。与对照相比，细菌接种土壤溶液中的 Cd 和 Pb 浓度降低，pH 值和 NH 浓度升高。这些结果表明，这些菌株通过降低金属有效性、增加 pH 值、ureC 基因相对丰度和脲酶活性，以及降低金属从叶片向块茎的转运，从而减少了块茎对金属的吸收。这些结果可能为利用金属固定化细菌（特别是菌株 CL-1）来减少金属污染土壤中马铃薯块茎对金属的吸收提供了一种有效的方法。
