State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, PR China.
State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, PR China.
Environ Pollut. 2018 Apr;235:700-709. doi: 10.1016/j.envpol.2018.01.006. Epub 2018 Jan 12.
A heterotrophic arsenite [As(III)]-oxidizing bacterium Agrobacterium tumefaciens GW4 isolated from As(III)-rich groundwater sediment showed high As(III) resistance and could oxidize As(III) to As(V). The As(III) oxidation could generate energy and enhance growth, and AioR was the regulator for As(III) oxidase. To determine the related metabolic pathways mediated by As(III) oxidation and whether AioR regulated other cellular responses to As(III), isobaric tags for relative and absolute quantitation (iTRAQ) was performed in four treatments, GW4 (+AsIII)/GW4 (-AsIII), GW4-ΔaioR (+AsIII)/GW4-ΔaioR (-AsIII), GW4-ΔaioR (-AsIII)/GW4 (-AsIII) and GW4-ΔaioR (+AsIII)/GW4 (+AsIII). A total of 41, 71, 82 and 168 differentially expressed proteins were identified, respectively. Using electrophoretic mobility shift assay (EMSA) and qRT-PCR, 12 genes/operons were found to interact with AioR. These results indicate that As(III) oxidation alters several cellular processes related to arsenite, such as As resistance (ars operon), phosphate (Pi) metabolism (pst/pho system), TCA cycle, cell wall/membrane, amino acid metabolism and motility/chemotaxis. In the wild type with As(III), TCA cycle flow is perturbed, and As(III) oxidation and fermentation are the main energy resources. However, when strain GW4-ΔaioR lost the ability of As(III) oxidation, the TCA cycle is the main way to generate energy. A regulatory cellular network controlled by AioR is constructed and shows that AioR is the main regulator for As(III) oxidation, besides, several other functions related to As(III) are regulated by AioR in parallel.
从富含砷地下水沉积物中分离到一株异养亚砷酸盐 [As(III)] 氧化菌根癌农杆菌 GW4，该菌具有较高的砷抗性，并能将 As(III)氧化为 As(V)。As(III) 氧化可以产生能量并促进生长，AioR 是 As(III)氧化酶的调控因子。为了确定 As(III)氧化介导的相关代谢途径，以及 AioR 是否调控其他细胞对 As(III)的响应，在 4 种处理中进行了相对和绝对定量同位素标记 (iTRAQ)，分别为 GW4(+AsIII)/GW4(-AsIII)、GW4-ΔaioR(+AsIII)/GW4-ΔaioR(-AsIII)、GW4-ΔaioR(-AsIII)/GW4(-AsIII)和 GW4-ΔaioR(+AsIII)/GW4(+AsIII)。分别鉴定出 41、71、82 和 168 个差异表达蛋白。通过电泳迁移率变动分析 (EMSA) 和 qRT-PCR，发现 12 个基因/操纵子与 AioR 相互作用。这些结果表明，As(III)氧化改变了与亚砷酸盐相关的几种细胞过程，如砷抗性 (ars 操纵子)、磷酸盐 (Pi) 代谢 (pst/pho 系统)、TCA 循环、细胞壁/膜、氨基酸代谢和运动/趋化性。在有 As(III)的野生型中，TCA 循环流动受到干扰，As(III)氧化和发酵是主要的能量来源。然而，当菌株 GW4-ΔaioR 失去 As(III)氧化能力时，TCA 循环是产生能量的主要途径。构建了一个由 AioR 控制的调控细胞网络，表明除了 As(III)氧化外，AioR 还是主要的调控因子，同时，AioR 还平行调控其他几种与 As(III)相关的功能。
