Shewanella oneidensis is a dissimilatory metal reducing bacterium and model for extracellular electron transfer (EET), a respiratory mechanism in which electrons are transferred out of the cell. In the last 10 years, migration to insoluble electron acceptors for EET has been shown to be nonrandom and tactic, seemingly in the absence of molecular or energy gradients that typically allow for taxis. As the ability to sense, locate, and respire electrodes has applications in bioelectrochemical technology, a better understanding of taxis in S. oneidensis is needed. While the EET conduits of S. oneidensis have been studied extensively, its taxis pathways and their interplay with EET are not yet understood, making investigation into taxis phenomena nontrivial. Since S. oneidensis is a member of an EET-encoding clade, the genetic circuitry of taxis to insoluble acceptors may be conserved. We performed a bioinformatic analysis of Shewanella genomes to identify S. oneidensis chemotaxis orthologs conserved in the genus. In addition to the previously reported core chemotaxis gene cluster, we identify several other conserved proteins in the taxis signaling pathway. We present the current evidence for the two proposed models of EET taxis, “electrokinesis” and flavin-mediated taxis, and highlight key areas in need of further investigation.
Bibliographical noteFunding Information:
This work was supported by a grant from the Office of Naval Research (N00014‐18‐1‐2632) to MYE‐N, DRB, and JAG. RSW was supported in part by a 3M Science and Technology Fellowship. The authors would also like to thank Bridget Conley (University of Minnesota) for critical feedback on the manuscript.
© 2020 John Wiley & Sons Ltd
Copyright 2020 Elsevier B.V., All rights reserved.
- dissimilatory iron reduction
- energy taxis
PubMed: MeSH publication types
- Journal Article