Genomic and Gene-Expression Comparisons among Phage-Resistant Type-IV Pilus Mutants of Pseudomonas syringae pathovar phaseolicola

Sistrom, Mark; Park, Derek; O’Brien, Heath; Wang, Zheng; Guttman, David S.; Townsend, Jeffrey P.; Turner, Paul

doi:10.1371/journal.pone.0144514

Cited by 12 publications

(9 citation statements)

References 48 publications

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“…Recently, Sistrom et al (2015) showed that P. syringae pv. phaseolicola can evolve resistance to phage φ6 by eliminating type-IV pili, but the phage mutants presented reduced virulence [53]. In our study, the experimental results of the fitness of phage showed that the concentration of sensitive bacteria and resistant mutants, when grown in the absence of phage φ6, are similar (Figure 7).…”

Section: Discussionsupporting

confidence: 51%

“…According to our results, this phage can be used also against other Pseudomonas syringae pathovars, such as P. syringae pv. syringae , which are important phytopathogens for the agriculture sector because they can easily infect several horticultural plants [4,52,53,54,55,56], causing severe economic losses worldwide.…”

Section: Discussionmentioning

confidence: 99%

“…However, phage φ6 has been shown to alter its host range, mostly through mutations in its receptor binding proteins [62]. The high mutation rate associated with its RNA-based genome allow it to exploit new niches by infecting closely related Pseudomonas species [53,63]. Nevertheless, in the future, new phages need to be isolated and tested together with phage φ6 in order to produce a cocktail with a broader spectrum of activity to control several pathovars of P. syringae .…”

Section: Discussionmentioning

confidence: 99%

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Efficiency of Phage φ6 for Biocontrol of Pseudomonas syringae pv. syringae: An in Vitro Preliminary Study

et al. 2019

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Pseudomonas syringae is a plant-associated bacterial species that has been divided into more than 60 pathovars, with the Pseudomonas syringae pv. syringae being the main causative agent of diseases in a wide variety of fruit trees. The most common treatments for biocontrol of P. syringae pv. syringae infections has involved copper derivatives and/or antibiotics. However, these treatments should be avoided due to their high toxicity to the environment and promotion of bacterial resistance. Therefore, it is essential to search for new approaches for controlling P. syringae pv. syringae. Phage therapy can be a useful alternative tool to the conventional treatments to control P. syringae pv. syringae infections in plants. In the present study, the efficacy of bacteriophage (or phage) φ6 (a commercially available phage) was evaluated in the control of P. syringae pv. syringae. As the plants are exposed to the natural variability of physical and chemical parameters, the influence of pH, temperature, solar radiation and UV-B irradiation on phage φ6 viability was also evaluated in order to develop an effective phage therapy protocol. The host range analysis revealed that the phage, besides its host (P. syringae pv. syringae), also infects the Pseudomonas syringae pv. actinidiae CRA-FRU 12.54 and P. syringae pv. actinidiae CRA-FRU 14.10 strains, not infecting strains from the other tested species. Both multiplicities of infection (MOIs) tested, 1 and 100, were effective to inactivate the bacterium, but the MOI 1 (maximum reduction of 3.9 log CFU/mL) was more effective than MOI 100 (maximum reduction of 2.6 log CFU/mL). The viability of phage φ6 was mostly affected by exposure to UV-B irradiation (decrease of 7.3 log PFU/mL after 8 h), exposure to solar radiation (maximum reduction of 2.1 PFU/mL after 6 h), and high temperatures (decrease of 8.5 PFU/mL after 6 days at 37 °C, but a decrease of only 2.0 log PFU/mL after 67 days at 15 °C and 25 °C). The host range, high bacterial control and low rates of development of phage-resistant bacterial clones (1.20 × 10−3) suggest that this phage can be used to control P. syringae pv. syringae infections in plants, but also to control infections by P. syringae pv. actinidiae, the causal agent of bacterial canker of kiwifruit. Although the stability of phage φ6 was affected by UV-B and solar radiation, this can be overcome by the application of phage suspensions at the end of the day or at night.

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Section: Discussionsupporting

confidence: 51%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Efficiency of Phage φ6 for Biocontrol of Pseudomonas syringae pv. syringae: An in Vitro Preliminary Study

et al. 2019

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“…In a global transcriptome analysis of phage-resistant A. baumanii, the expression of vgrG was downregulated by two-fold and a subset of seven other genes involved in Type II, V, and VI secretion were also significantly downregulated [25]. Upregulation of virulence factors as a result of phage resistance has been reported elsewhere [51,52].…”

Section: Adhesion and Invasion Assaysmentioning

confidence: 87%

Bacteriophage-Insensitive Mutants of Antimicrobial-Resistant Salmonella Enterica are Altered in their Tetracycline Resistance and Virulence in Caco-2 Intestinal Cells

Fong

Rheault

et al. 2020

IJMS

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Bacteriophages have shown promise as therapeutic alternatives to antibiotics for the control of infectious bacteria, including the human pathogen Salmonella. However, the development of effective phage-based applications requires the elucidation of key interactions between phages and target hosts, particularly since host resistance to phage is inevitable. Little is known about the alteration of host phenotypes following the development of resistance to phage. The aim of this study is to evaluate the antibiotic susceptibility and virulence of a Salmonella isolate following the development of resistance to bacteriophage SI1. We observed enhanced susceptibility to tetracycline and decreased invasion capacity in a differentiated Caco-2 intestinal cell line. Whole genome sequence analysis revealed an array of mutations, most notably, truncations in vgrG1_2, a core gene involved in Type VI secretion and mutations in the lipopolysaccharide, thereby indicating the plausible attachment site of phage SI1. These findings shed light on understanding the underlying mechanism for phage immunity within the host. Importantly, we reveal an associated genetic cost to the bacterial host with developing resistance to phages. Taken together, these results will aid in advancing strategies to delay or eliminate the development of host resistance when designing informed phage-based antimicrobials.

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“…Several studies have investigated the effect of type IV pilus mutations and phage resistance. Interestingly, phage F6, a dsRNA cystovirus of Pseudomonas syringae pathovar phaseolicola, selects for several types of mutants that differ in the number of type IV pili expressed per cell, but none of the mutated genes is known to be directly involved in type IV pilus expression (Sistrom et al, 2015).…”

Section: Cross-resistance and Reversibility Of Mutantsmentioning

confidence: 99%

Pseudolysogeny and sequential mutations build multiresistance to virulent bacteriophages in Pseudomonas aeruginosa

Latino

2016

Microbiology

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Coevolution between bacteriophages (phages) and their prey is the result of mutualistic interactions. Here, we show that pseudolysogeny is a frequent outcome of infection by virulent phages of Pseudomonas aeruginosa and that selection of resistant bacterial mutants is favoured by continuous production of phages. We investigated the frequency and characteristics of P. aeruginosa strain PAO1 variants resisting infection by different combinations of virulent phages belonging to four genera. The frequency of resistant bacteria was 10 25 for single phage infection and 10 26 for infections with combinations of two or four phages. The genome of 27 variants was sequenced and the comparison with the genome of the parental PAO1 strain allowed the identification of point mutations or small indels. Four additional variants were characterized by a candidate gene approach. In total, 27 independent mutations were observed affecting 14 genes and a regulatory region. The mutations affected genes involved in biosynthesis of type IV pilus, alginate, LPS and O-antigen. Half of the variants possessed changes in homopolymer tracts responsible for frameshift mutations and these phase variation mutants were shown to be unstable. Eleven double mutants were detected. The presence of free phage DNA was observed in association with exclusion of superinfection in half of the variants and no chromosomal mutation could be found in three of them. Upon further growth of these pseudolysogens, some variants with new chromosomal mutations were recovered, presumably due to continuous evolutionary pressure.

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Genomic and Gene-Expression Comparisons among Phage-Resistant Type-IV Pilus Mutants of Pseudomonas syringae pathovar phaseolicola

Cited by 12 publications

References 48 publications

Efficiency of Phage φ6 for Biocontrol of Pseudomonas syringae pv. syringae: An in Vitro Preliminary Study

Efficiency of Phage φ6 for Biocontrol of Pseudomonas syringae pv. syringae: An in Vitro Preliminary Study

Bacteriophage-Insensitive Mutants of Antimicrobial-Resistant Salmonella Enterica are Altered in their Tetracycline Resistance and Virulence in Caco-2 Intestinal Cells

Pseudolysogeny and sequential mutations build multiresistance to virulent bacteriophages in Pseudomonas aeruginosa

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