"Influence of plasmids, selection markers and auxotrophic mutations on Haloferax volcanii cell shape plasticity"

Megha Patro; Iain G Duggin; Sonja-Verena Albers; Solenne Ithurbide

doi:10.3389/fmicb.2023.1270665

"Influence of plasmids, selection markers and auxotrophic mutations on Haloferax volcanii cell shape plasticity"

Front Microbiol. 2023 Sep 29:14:1270665. doi: 10.3389/fmicb.2023.1270665. eCollection 2023.

Authors

Megha Patro^{1

2}, Iain G Duggin³, Sonja-Verena Albers¹, Solenne Ithurbide¹

Affiliations

¹ Molecular Biology of Archaea, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany.
² Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany.
³ The Australian Institute for Microbiology and Infection, University of Technology Sydney, Sydney, NSW, Australia.

Abstract

Haloferax volcanii and other Haloarchaea can be pleomorphic, adopting different shapes, which vary with growth stages. Several studies have shown that H. volcanii cell shape is sensitive to various external factors including growth media and physical environment. In addition, several studies have noticed that the presence of a recombinant plasmid in the cells is also a factor impacting H. volcanii cell shape, notably by favoring the development of rods in early stages of growth. Here we investigated the reasons for this phenomenon by first studying the impact of auxotrophic mutations on cell shape in strains that are commonly used as genetic backgrounds for selection during strain engineering (namely: H26, H53, H77, H98, and H729) and secondly, by studying the effect of the presence of different plasmids containing selection markers on the cell shape of these strains. Our study showed that most of these auxotrophic strains have variation in cell shape parameters including length, aspect ratio, area and circularity and that the plasmid presence is impacting these parameters too. Our results indicated that ΔhdrB strains and hdrB selection markers have the most influence on H. volcanii cell shape, in addition to the sole presence of a plasmid. Finally, we discuss limitations in studying cell shape in H. volcanii and make recommendations based on our results for improving reproducibility of such studies.

Keywords: HDRB; Haloferax volcanii; auxotrophy; cell shape; haloarchaea; plasmid.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. SI was supported by a Momentum grant from the VW Science Foundation (grant number 94933) granted to S-VA. MP was supported by grant AL1206/4-3 by the German Science Foundation (DFG). ID was supported by the Australian Research Council (DP160101076 and FT160100010).