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Transcriptional changes when Myxococcus xanthus preys on Escherichia coli suggest myxobacterial predators are constitutively toxic but regulate their feeding.

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journal contribution
posted on 30.01.2018, 15:31 by Paul G. Livingstone, Andrew D. Millard, Martin T. Swain, David E. Whitworth
Predation is a fundamental ecological process, but within most microbial ecosystems the molecular mechanisms of predation remain poorly understood. We investigated transcriptome changes associated with the predation of Escherichia coli by the myxobacterium Myxococcus xanthus using mRNA sequencing. Exposure to pre-killed prey significantly altered expression of 1319 predator genes. However, the transcriptional response to living prey was minimal, with only 12 genes being significantly up-regulated. The genes most induced by prey presence (kdpA and kdpB, members of the kdp regulon) were confirmed by reverse transcriptase quantitative PCR to be regulated by osmotic shock in M. xanthus, suggesting indirect sensing of prey. However, the prey showed extensive transcriptome changes when co-cultured with predator, with 40 % of its genes (1534) showing significant changes in expression. Bacteriolytic M. xanthus culture supernatant and secreted outer membrane vesicles (OMVs) also induced changes in expression of large numbers of prey genes (598 and 461, respectively). Five metabolic pathways were significantly enriched in prey genes up-regulated on exposure to OMVs, supernatant and/or predatory cells, including those for ribosome and lipopolysaccharide production, suggesting that the prey cell wall and protein production are primary targets of the predator's attack. Our data suggest a model of the myxobacterial predatome (genes and proteins associated with predation) in which the predator constitutively produces secretions which disable its prey whilst simultaneously generating a signal that prey is present. That signal then triggers a regulated feeding response in the predator.

Funding

This work was funded by a grant from the Aberystwyth University Research Fund. The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication. IBERS receives strategic funding from the BBSRC.

History

Citation

Microbial Genomics, 2018, 5

Author affiliation

/Organisation/COLLEGE OF LIFE SCIENCES/School of Medicine/Department of Infection, Immunity and Inflammation

Version

VoR (Version of Record)

Published in

Microbial Genomics

Publisher

Microbiology Society

eissn

2057-5858

Acceptance date

21/12/2017

Copyright date

2018

Available date

30/01/2018

Publisher version

http://mgen.microbiologyresearch.org/content/journal/mgen/10.1099/mgen.0.000152

Notes

Supplementary material is available with the online version of this article. Reads from all sequencing experiments are deposited under accession numbers SRX3143879, SRX3143880, SRX3143934, SRX3143935, SRX3143947, SRX3143951, SRX3143956, SRX3143960 and SRX3143962 at the Sequence Read Archive: https://www.ncbi.nlm.nih.gov/sra.

Language

en