Energy Biosciences Institute, University of California- Berkeley, Berkeley, CA, USA.
Department of Plant and Microbial Biology, University of California- Berkeley, Berkeley, CA, USA.
Environ Microbiol. 2019 Apr;21(4):1395-1406. doi: 10.1111/1462-2920.14570. Epub 2019 Mar 19.
Hydrogen sulfide produced by sulfate-reducing microorganisms (SRM) poses significant health and economic risks, particularly during oil recovery. Previous studies identified perchlorate as a specific inhibitor of SRM. However, constant inhibitor addition to natural systems results in new selective pressures. Consequently, we investigated the ability of Desulfovibrio alaskensis G20 to evolve perchlorate resistance. Serial transfers in increasing concentrations of perchlorate led to robust growth in the presence of 100 mM inhibitor. Isolated adapted strains demonstrated a threefold increase in perchlorate resistance compared to the wild-type ancestor. Whole genome sequencing revealed a single base substitution in Dde_2265, the sulfate adenylyltransferase (sat). We purified and biochemically characterized the Sat from both wild-type and adapted strains, and showed that the adapted Sat was approximately threefold more resistant to perchlorate inhibition, mirroring whole cell results. The ability of this mutation to confer resistance across other inhibitors of sulfidogenesis was also assayed. The generalizability of this mutation was confirmed in multiple evolving G20 cultures and in another SRM, D. vulgaris Hildenborough. This work demonstrates that a single nucleotide polymorphism in Sat can have a significant impact on developing perchlorate resistance and emphasizes the value of adaptive laboratory evolution for understanding microbial responses to environmental perturbations.
硫酸盐还原微生物（SRM）产生的硫化氢会对健康和经济造成重大风险，尤其是在采油过程中。先前的研究已经确定高氯酸盐是 SRM 的特定抑制剂。然而，在自然系统中持续添加抑制剂会产生新的选择性压力。因此，我们研究了脱硫弧菌 G20 对高氯酸盐抗性的进化能力。在逐渐增加高氯酸盐浓度的连续传代中，在 100mM 抑制剂存在的情况下实现了旺盛的生长。与野生型祖先相比，分离出的适应株表现出对高氯酸盐抗性增加了三倍。全基因组测序揭示了硫酸盐腺苷酰转移酶（sat）基因 Dde_2265 中的单个碱基取代。我们从野生型和适应株中纯化并对 Sat 进行了生化特性分析，结果表明适应株 Sat 对高氯酸盐的抑制作用的抗性大约增加了三倍，与全细胞结果相吻合。还检测了该突变赋予其他硫化物生成抑制剂抗性的能力。该突变在多个进化 G20 培养物和另一种 SRM 脱硫菌（D. vulgaris Hildenborough）中得到了证实。这项工作表明，Sat 中的单个核苷酸多态性会对高氯酸盐抗性的发展产生重大影响，并强调了适应性实验室进化在理解微生物对环境扰动的反应方面的价值。
