Microbial Biotechnology and Health, Institute of Biology, Leiden University, Leiden, The Netherlands.
Institute of Applied Microbiology - iAMB, Aachen Biology and Biotechnology - ABBt, RWTH Aachen University, Aachen, Germany.
Microb Biotechnol. 2017 Nov;10(6):1558-1568. doi: 10.1111/1751-7915.12495. Epub 2017 Apr 11.
Organic solvent-tolerant bacteria are outstanding and versatile hosts for the bio-based production of a broad range of generally toxic aromatic compounds. The energetically costly solvent tolerance mechanisms are subject to multiple levels of regulation, involving among other mobile genetic elements. The genome of the solvent-tolerant Pseudomonas putida S12 contains many such mobile elements that play a major role in the regulation and adaptation to various stress conditions, including the regulation of expression of the solvent efflux pump SrpABC. We recently sequenced the genome of P. putida S12. Detailed annotation identified a threefold higher copy number of the mobile element ISS12 in contrast to earlier observations. In this study, we describe the mobile genetic elements and elaborate on the role of ISS12 in the establishment and maintenance of solvent tolerance in P. putida. We identified three different variants of ISS12 of which a single variant exhibits a high translocation rate. One copy of this variant caused a loss of solvent tolerance in the sequenced strain by disruption of srpA. Solvent tolerance could be restored by applying selective pressure, leading to a clean excision of the mobile element.
有机溶剂耐受细菌是生物基生产广泛的一般毒性芳香族化合物的出色且多功能的宿主。能源成本高的溶剂耐受机制受到多层次的调节，涉及其他移动遗传元件。耐溶剂假单胞菌 S12 的基因组包含许多这样的移动元件，它们在调节和适应各种应激条件中发挥主要作用，包括对溶剂外排泵 SrpABC 的表达调控。我们最近对 P. putida S12 的基因组进行了测序。详细的注释表明，与早期观察到的相比，移动元件 ISS12 的拷贝数增加了三倍。在这项研究中，我们描述了移动遗传元件，并详细阐述了 ISS12 在 P. putida 中建立和维持溶剂耐受性中的作用。我们鉴定了三种不同的 ISS12 变体，其中一种变体具有很高的转位率。通过破坏 srpA，该变体的一个拷贝会导致测序菌株失去溶剂耐受性。通过施加选择压力可以恢复溶剂耐受性，从而导致移动元件的干净切除。
