Temperate phages promote colicin‐dependent fitness of <scp><i>S</i></scp><i>almonella enterica</i> serovar <scp>T</scp>yphimurium

Nedialkova, Lubov; Sidstedt, M.; Koeppel, Martin B.; Spriewald, Stefanie; Ring, Diana; Gerlach, Roman G.; Bossi, Lionello; Stecher, Bärbel

doi:10.1111/1462-2920.13077

Cited by 35 publications

(38 citation statements)

References 53 publications

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“…The resulting heterodimeric complex is often released from the cell through the action of a bacteriocin-release protein or lysis protein, which is often encoded within bacteriocin operons [ 13 ]. In cases where a bacteriocin-release protein has not been identified latent prophage genes have been implicated in release [ 33 ]. NB-specific immunity proteins are only jettisoned during translocation of the toxin into a susceptible cell [ 17 ].…”

Section: Resultsmentioning

confidence: 99%

Diversity and distribution of nuclease bacteriocins in bacterial genomes revealed using Hidden Markov Models

et al. 2017

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Bacteria exploit an arsenal of antimicrobial peptides and proteins to compete with each other. Three main competition systems have been described: type six secretion systems (T6SS); contact dependent inhibition (CDI); and bacteriocins. Unlike T6SS and CDI systems, bacteriocins do not require contact between bacteria but are diffusible toxins released into the environment. Identified almost a century ago, our understanding of bacteriocin distribution and prevalence in bacterial populations remains poor. In the case of protein bacteriocins, this is because of high levels of sequence diversity and difficulties in distinguishing their killing domains from those of other competition systems. Here, we develop a robust bioinformatics pipeline exploiting Hidden Markov Models for the identification of nuclease bacteriocins (NBs) in bacteria of which, to-date, only a handful are known. NBs are large (>60 kDa) toxins that target nucleic acids (DNA, tRNA or rRNA) in the cytoplasm of susceptible bacteria, usually closely related to the producing organism. We identified >3000 NB genes located on plasmids or on the chromosome from 53 bacterial species distributed across different ecological niches, including human, animals, plants, and the environment. A newly identified NB predicted to be specific for Pseudomonas aeruginosa (pyocin Sn) was produced and shown to kill P. aeruginosa thereby validating our pipeline. Intriguingly, while the genes encoding the machinery needed for NB translocation across the cell envelope are widespread in Gram-negative bacteria, NBs are found exclusively in γ-proteobacteria. Similarity network analysis demonstrated that NBs fall into eight groups each with a distinct arrangement of protein domains involved in import. The only structural feature conserved across all groups was a sequence motif critical for cell-killing that is generally not found in bacteriocins targeting the periplasm, implying a specific role in translocating the nuclease to the cytoplasm. Finally, we demonstrate a significant association between nuclease colicins, NBs specific for Escherichia coli, and virulence factors, suggesting NBs play a role in infection processes, most likely by enabling pathogens to outcompete commensal bacteria.

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Section: Resultsmentioning

confidence: 99%

Diversity and distribution of nuclease bacteriocins in bacterial genomes revealed using Hidden Markov Models

et al. 2017

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“…The diameter of colonies was measured at 6 days. The media used for assays include the CM medium 46 , CM medium supplemented with 1.2 M sorbitol or 200 μg/ml congo red 47 , 1.2% agar, Czapek-Dox medium, nitrogen or carbon starvation medium 48 and rice medium with pH 8.0 or 5.0 49 , 1/10 CM medium supplemented with 8 μM DTPA 50 .…”

Section: Methodsmentioning

confidence: 99%

The Nep1-like protein family of Magnaporthe oryzae is dispensable for the infection of rice plants

Fang

Peng

Fan

2017

Sci Rep

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The necrosis- and ethylene-inducing protein 1 (Nep1)-like proteins (NLPs) are a class of microbe-associated molecular patterns widely distributed across diverse groups of plant-associated microorganisms. In spite of the cytotoxic activity in dicot plants, the role of most NLPs in the virulence of plant pathogens is still largely unknown. We showed that the MoNLP family of rice blast fungus varied very little in amino acid sequence, transient expression of three MoNLPs induced cell death and the production of reactive oxygen species in Nicotiana benthamiana, and the expression of MoNLPs was induced during infection of susceptible rice plants. To further investigate the biological role of the MoNLP family, a marker-free gene replacement vector was developed and used to knock out the whole family in Magnaporthe oryzae. Results showed no significant difference in disease levels caused by wild type and the quadruple ΔMoNLP mutant strains. Likewise, the sporulation and radial growth of the two strains were similar under various unfavorable cultural conditions including malnutrition and abiotic stresses. These observations demonstrated that the MoNLP family is dispensable for the fungal tolerance to the tested adverse cultural conditions, and more importantly, for the virulence of blast fungus on susceptible rice plants.

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“…However, phages can also influence bacterial physiology by other means. For example, the release of colicin 1b in S. enterica SL1344 depends on the lysis genes of the ST64B prophage (Nedialkova et al ., ). Indeed, under specific conditions such as DNA damage or iron limitation, colicin 1b accumulates in the cell and needs the induction of ST64B lysis genes to be found in the extracellular medium.…”

Section: Host‐prophage Regulatory Networkmentioning

confidence: 97%

Prophages in Salmonella enterica: a driving force in reshaping the genome and physiology of their bacterial host?

Wahl

Battesti

Ansaldi

2018

Molecular Microbiology

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Thanks to the exponentially increasing number of publicly available bacterial genome sequences, one can now estimate the important contribution of integrated viral sequences to the diversity of bacterial genomes. Indeed, temperate bacteriophages are able to stably integrate the genome of their host through site-specific recombination and transmit vertically to the host siblings. Lysogenic conversion has been long acknowledged to provide additional functions to the host, and particularly to bacterial pathogen genomes where prophages contribute important virulence factors. This review aims particularly at highlighting the current knowledge and questions about lysogeny in Salmonella genomes where functional prophages are abundant, and where genetic interactions between host and prophages are of particular importance for human health considerations.

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Temperate phages promote colicin‐dependent fitness of Salmonella enterica serovar Typhimurium

Cited by 35 publications

References 53 publications

Diversity and distribution of nuclease bacteriocins in bacterial genomes revealed using Hidden Markov Models

Diversity and distribution of nuclease bacteriocins in bacterial genomes revealed using Hidden Markov Models

The Nep1-like protein family of Magnaporthe oryzae is dispensable for the infection of rice plants

Prophages in Salmonella enterica: a driving force in reshaping the genome and physiology of their bacterial host?

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