Institute of Microbiology, Faculty of Biosciences, Friedrich Schiller University Jenagrid.9613.d, Jena, Germany.
Leibniz Institute for Natural Compound Research and Infection Biology- Hans Knöll Institute, Jena, Germany.
Appl Environ Microbiol. 2022 Jun 14;88(11):e0008522. doi: 10.1128/aem.00085-22. Epub 2022 May 23.
The extreme metal tolerance of up to 130 mM NiSO in Streptomyces mirabilis P16B-1 was investigated. Genome sequencing revealed the presence of a large linear plasmid, pI. To identify plasmid-encoded determinants of metal resistance, a newly established transformation system was used to characterize the predicted plasmid-encoded loci , and . Reintroduction into the plasmid-cured S. mirabilis ΔpI confirmed that the predicted metal transporter gene constitutes a nickel resistance factor, which was further supported by its heterologous expression in Escherichia coli. In contrast, the predicted nickel exporter gene decreased nickel tolerance, while copper tolerance was enhanced. The predicted copper-dependent transcriptional regulator gene did not induce tolerance toward either metal. Since genes for transfer were identified on the plasmid, its conjugational transfer to the metal-sensitive Streptomyces lividans TK24 was checked. This resulted in acquired tolerance toward 30 mM nickel and additionally increased the tolerance toward copper and cobalt, while oxidative stress tolerance remained unchanged. Intracellular nickel concentrations decreased in the transconjugant strain. The high extracellular nickel concentrations allowed for biomineralization. Plasmid transfer could also be confirmed into the co-occurring actinomycete spp. in soil microcosms. Living in extremely metal-rich environments requires specific adaptations, and often, specific metal tolerance genes are encoded on a transferable plasmid. Here, Streptomyces mirabilis P16B-1, isolated from a former mining area and able to grow with up to 130 mM NiSO, was investigated. The bacterial chromosome, as well as a giant plasmid, was sequenced. The plasmid-borne gene was confirmed to confer metal resistance. A newly established transformation system allowed us to construct a plasmid-cured S. mirabilis as well as an -rescued strain in addition to confirming encoding nickel resistance if heterologously expressed in E. coli. The potential of intra- and interspecific plasmid transfer, together with the presence of metal resistance factors on that plasmid, underlines the importance of plasmids for transfer of resistance factors within a bacterial soil community.
研究了一株 Streptomyces mirabilis P16B-1 对高达 130mM NiSO 的极端金属耐受性。基因组测序揭示了一个大型线性质粒 pI 的存在。为了鉴定质粒编码的金属抗性决定因素，建立了一个新的转化系统来表征预测的质粒编码基因 和 。将其重新引入质粒缺失的 S. mirabilis ΔpI 中证实，预测的金属转运基因 构成了镍抗性因子，这一结果在大肠杆菌中的异源表达中得到了进一步支持。相比之下，预测的镍外排基因 降低了镍耐受性，而铜耐受性增强。预测的铜依赖型转录调节基因 对两种金属均未诱导出耐受性。由于质粒上鉴定出了转移基因，因此检查了其向金属敏感的 Streptomyces lividans TK24 的共轭转移。这导致对 30mM 镍的获得性耐受性增加，并且还增加了对铜和钴的耐受性，而氧化应激耐受性保持不变。转导株细胞内镍浓度降低。高浓度的细胞外镍允许生物矿化。质粒转移也可以在土壤微宇宙中的共生放线菌 spp. 中得到确认。生活在富含金属的极端环境中需要特定的适应，通常，特定的金属耐受性基因编码在可转移的质粒上。在这里，研究了一株从以前的采矿区分离出来的、能够在高达 130mM NiSO 的条件下生长的 Streptomyces mirabilis P16B-1。测序了细菌染色体和一个巨大的质粒。证实了质粒携带的基因 赋予了金属抗性。建立的新转化系统允许我们构建质粒缺失的 S. mirabilis 以及 拯救菌株，除了确认在大肠杆菌中异源表达时 编码镍抗性。质粒的种内和种间转移潜力以及该质粒上存在金属抗性因子，突出了质粒在细菌土壤群落中转移抗性因子的重要性。
