Genetic and plasmid diversity within natural populations of Pseudomonas syringae with various exposures to copper and streptomycin bactericides

Sundin, George W.; Demezas, David H.; Bender, Carol L.

doi:10.1128/aem.60.12.4421-4431.1994

Cited by 77 publications

(29 citation statements)

References 62 publications

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“…The incidence of Sm resistance in pathogenic and commensal bacteria in clinical and agricultural habitats is often high and this has most likely been caused by the use of Sm in these environments [3,32,33]. However, the spread and distribution of these genes in pristine habitats, i.e.…”

Section: Discussionmentioning

confidence: 99%

Prevalence of streptomycin-resistance genes in bacterial populations in European habitats

VANOVERBEEK¹,

WELLINGTON²,

EGAN³

et al. 2002

FEMS Microbiology Ecology

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The prevalence of selected streptomycin (Sm)-resistance genes, i.e. aph (3''), aph (6)-1d, aph (6)-1c, ant (3'') and ant (6), was assessed in a range of pristine as well as polluted European habitats. These habitats included bulk and rhizosphere soils, manure from farm animals, activated sludge from wastewater treatment plants and seawater. The methods employed included assessments of the prevalence of the genes in habitat-extracted DNA by PCR, followed by hybridisation with specific probes, Sm-resistant culturable bacteria and exogenous isolation of plasmids carrying Sm-resistance determinants. The direct DNA-based analysis showed that aph (6)-1d genes were most prevalent in the habitats examined. The presence of the other four Sm-modifying genes was demonstrated in 58% of the tested habitats. A small fraction of the bacterial isolates (8%) did not possess any of the selected Sm-modifying genes. These isolates were primarily obtained from activated sludge and manure. The presence of Sm-modifying genes in the isolates often coincided with the presence of IncP plasmids. Exogenous isolation demonstrated the presence of plasmids of 40-200 kb in size harbouring Sm-resistance genes from all the environments tested. Most plasmids were shown to carry the ant (3'') gene, often in combination with other Sm-resistance genes, such as aph (3'') and aph (6)-1d. The most commonly found Sm-modifying gene on mobile genetic elements was ant (3''). Multiple Sm-resistance genes on the same genetic elements appeared to be the rule rather than the exception. It is concluded that Sm-resistance genes are widespread in the environmental habitats studied and often occur on mobile genetic elements and ant (3'') was most often encountered.

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Section: Discussionmentioning

confidence: 99%

Prevalence of streptomycin-resistance genes in bacterial populations in European habitats

VANOVERBEEK¹,

WELLINGTON²,

EGAN³

et al. 2002

FEMS Microbiology Ecology

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“…syringae strains. AP-PCR analysis is a useful tool for distinguishing individual strains within a related taxonomic group and has been used successfully with plant pathogenic bacteria for intrapathovar strain differentiation (Louws et al, 1994;Sundin et al, 1994). In our AP-PCR experiments, DNA fragment patterns were generated, analysed from multiple agarose gels, and a matrix indicating the presence or absence of particular fragments among strains was constructed (data not shown).…”

Section: Uv-b Tolerance Assays Of Phyllosphere Populationsmentioning

confidence: 99%

“…To this reaction mixture, we added approximately 10 6 cells (previously grown on PAF medium for 12 h) with a sterile toothpick, and the mixture was covered with one drop of mineral oil. The amplification cycles, electrophoresis of PCR products and visualization of strain-specific PCR patterns were as described previously (Sundin et al, 1994). The AP-PCR product data were converted into a two-dimensional binary matrix in which 1 indicated that a particular PCR product was present and 0 indicated the absence of a particular PCR product.…”

Section: Arbitrarily Primed Pcr Analysismentioning

confidence: 99%

Functional analysis of the Pseudomonas syringae rulAB determinant in tolerance to ultraviolet B (290–320 nm) radiation and distribution of rulAB among P. syringae pathovars

Sundin

Murillo

1999

Environmental Microbiology

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The effect of the plasmid-encoded rulAB (resistance to ultraviolet radiation) determinant on responses of Pseudomonas syringae to ultraviolet-B (UV-B) radiation and the distribution of rulAB among pathovars of P. syringae were determined. The cloned rulAB determinant and the native rulAB+ plasmid pPSR1 both conferred approximately a 10-fold increase in survival on P. syringae pv. syringae FF5 following increasing doses of UV-B radiation. rulAB+ P. syringae strains also maintained significantly larger epiphytic populations on leaf surfaces irradiated with UV-B. rulAB-insertional mutants, constructed in two native rulAB+ strains, were from 10- to 100-fold more sensitive to UV-B radiation. The UV tolerance phenotype and the rulAB genes were widely distributed among P. syringae pathovars isolated from varied plant hosts throughout the world and within a broad range of genotypic backgrounds of P. syringae pv. syringae. With one exception, the rulAB determinant was harboured on pPT23A-like plasmids; these replicons are indigenous residents of the species P. syringae and also tend to encode determinants of importance in host-pathogen interactions.

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“…Additionally, plasmids of P. syringae have a mosaic structure and often share extensive regions of similarity, suggesting their evolution through the acquisition and loss of large DNA regions in a multistep process [17-20, 23, 26]. Despite this, plasmid profiles of individual strains appear to be characteristic and stable, although certain plasmids can be lost with high frequency under certain culture conditions [3,[27][28][29][30]. In fact, diverse potential stability determinants were identified among PFP plasmids [18,20,21,[31][32][33], although it is not yet clear whether or not they are functional and what their role in the bacterial life cycle is.…”

Section: Thementioning

confidence: 99%

Integrity and stability of virulence plasmids fromPseudomonas syringaeare modulated by mobile genetic elements and multiple toxin-antitoxin systems

Bardaji

Añorga

Echeverría

et al. 2018

Preprint

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Background: Virulence plasmids are critically exposed to genetic decay and loss, particularly in Pseudomonas syringae strains because of their high content of mobile genetic elements and their exploitation of environmental niches outside of the plant host. The demonstrated high plasticity and adaptability of P. syringae plasmids, involving the acquisition and loss of large DNA regions, contrasts with their usual high stability and the maintenance of key virulence genes in free living conditions. The identification of plasmid stability determinants and mechanisms will help to understand their evolution and adaptability to agroecosystems as well as to develop more efficient control measures. Results:We show that the three virulence plasmids of P. syringae pv. savastanoi NCPPB 3335 contain diverse functional stability determinants, including three toxin-antitoxin systems (TA) in both pPsv48A and pPsv48C, whereas one of the two replicons of pPsv48C can confer stable inheritance by itself. Loss of pPsv48A increased by two orders of magnitude upon functional inactivation of its TA systems. However, inactivation of the TA systems from pPsv48C did not result in its curing but led to the recovery of diverse deletion derivatives. One type consisted in the deletion of an 8.3 kb fragment, with a frequency of 3.8 ± 0.3 × 10 -3 , by recombination between two copies of MITEPsy2. Likewise, IS801 promoted the occurrence of deletions of variable size by one-ended transposition with a frequency of 5.5 ± 2.1 × 10 -4 , 80 % of which resulted in the loss of virulence gene idi. These deletion derivatives were stably maintained in the population by replication mediated by repJ, which is adjacent to IS801. IS801 also promoted deletions in plasmid pPsv48A, either by recombination or one-ended transposition. In all cases, functional TA systems contributed significantly to reduce the occurrence of plasmid deletions in vivo. Conclusions:Virulence plasmids from P. syringae harbour a diverse array of stability determinants with a variable contribution to plasmid persistence. Additionally, multiple TA systems favour the long-term survival and integrity of virulence plasmids, as well as the maintenance of pathogenicity genes in free-living conditions. This strategy is likely widespread amongst native plasmids of P. syringae and other bacteria.(MINECO), co-financed by the Fondo Europeo de Desarrollo Regional (FEDER).

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Genetic and plasmid diversity within natural populations of Pseudomonas syringae with various exposures to copper and streptomycin bactericides

Cited by 77 publications

References 62 publications

Prevalence of streptomycin-resistance genes in bacterial populations in European habitats

Prevalence of streptomycin-resistance genes in bacterial populations in European habitats

Functional analysis of the Pseudomonas syringae rulAB determinant in tolerance to ultraviolet B (290–320 nm) radiation and distribution of rulAB among P. syringae pathovars

Integrity and stability of virulence plasmids fromPseudomonas syringaeare modulated by mobile genetic elements and multiple toxin-antitoxin systems

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