Resistance of the oyster pathogen <i>Vibrio tasmaniensis</i> LGP32 against grazing by <i>Vannella</i> sp. marine amoeba involves Vsm and CopA virulence factors

Robino, Etienne; Poirier, Aurore; Amraoui, Hajar; Bissonnais, Sandra Le; Perret, Angélique; López-Joven, Carmen; Auguet, Jean‐Christophe; Rubio, Tristan; Cazevieille, Chantal; Rolland, Jean‐Luc; Héchard, Yann; Destoumieux-Garzón, D.; Charrière, Guillaume M.

doi:10.1111/1462-2920.14770

Cited by 10 publications

(17 citation statements)

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“…To study marine bacteria-amoeba interactions, we first tried to axenize amoebae (such as Acanthamoeba griffini CCAP 1501/4 and Vahlkampfia dumnonica CCAP 1588/9) isolated from marine environments recovered from the marine culture collection (Culture Collection of Algae and Protozoa CCAP/The Scottish Association for Marine Science (SAMS)), but without success. We then decided to perform our experiments with a well-known amoeba model Acanthamoeba castellanii , which has previously been isolated from marine environments and studied in interaction with marine bacteria such as Vibrio strains [ 1 , 10 , 11 , 25 , 37 , 38 ].…”

Section: Resultsmentioning

confidence: 99%

Marine Bacteria Display Different Escape Mechanisms When Facing Their Protozoan Predators

2020

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Free-living amoeba are members of microbial communities such as biofilms in terrestrial, fresh, and marine habitats. Although they are known to live in close association with bacteria in many ecosystems such as biofilms, they are considered to be major bacterial predators in many ecosystems. Little is known on the relationship between protozoa and marine bacteria in microbial communities, more precisely on how bacteria are able survive in environmental niches where these bacterial grazers also live. The objective of this work is to study the interaction between the axenized ubiquitous amoeba Acanthamoeba castellanii and four marine bacteria isolated from immersed biofilm, in order to evaluate if they would be all grazed upon by amoeba or if they would be able to survive in the presence of their predator. At a low bacteria-to-amoeba ratio, we show that each bacterium is phagocytized and follows a singular intracellular path within this host cell, which appears to delay or to prevent bacterial digestion. In particular, one of the bacteria was found in the amoeba nucleolar compartment whereas another strain was expelled from the amoeba in vesicles. We then looked at the fate of the bacteria grown in a higher bacteria-to-amoeba ratio, as a preformed mono- or multi-species biofilm in the presence of A. castellanii. We show that all biofilms were subjected to detachment from the surface in the presence of the amoeba or its supernatant. Overall, these results show that bacteria, when facing the same predator, exhibit a variety of escape mechanisms at the cellular and population level, when we could have expected a simple bacterial grazing. Therefore, this study unravels new insights into the survival of environmental bacteria when facing predators that they could encounter in the same microbial communities.

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Section: Resultsmentioning

confidence: 99%

Marine Bacteria Display Different Escape Mechanisms When Facing Their Protozoan Predators

2020

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“…Marine amoebae Vannella sp. AP1411 (Robino et al, 2019) was grown for 3 days prior experiments at 18 C in 70% sterile seawater (70% SSW), using E. coli SBS363 as a nutritive source. Other strains, plasmids and primers used are included in Tables S2-S4.…”

Section: Methodsmentioning

confidence: 99%

Vibrio splendidus O‐antigen structure: a trade‐off between virulence to oysters and resistance to grazers

Oyanedel

Labreuche

Bruto

et al. 2020

Environmental Microbiology

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A major debate in evolutionary biology is whether virulence is maintained as an adaptive trait and/or evolves to non-virulence. In the environment, virulence traits of non-obligatory parasites are subjected to diverse selective pressures and trade-offs. Here, we focus on a population of Vibrio splendidus that displays moderate virulence for oysters. A MARTX (Multifunctional-autoprocessing repeats-in-toxin) and a type-six secretion system (T6SS) were found to be necessary for virulence toward oysters, while a region (wbe) involved in O-antigen synthesis is necessary for resistance to predation against amoebae. Gene inactivation within the wbe region had major consequences on the O-antigen structure, conferring lower immunogenicity, competitive advantage and increased virulence in oyster experimental infections. Therefore, O-antigen structures that favour resistance to environmental predators result in an increased activation of the oyster immune system and a reduced virulence in that host. These trade-offs likely contribute to maintaining O-antigen diversity in the marine environment by favouring genomic plasticity of the wbe region. The results of this study indicate an evolution of V. splendidus towards moderate virulence as a compromise between fitness in the oyster as a host, and resistance to its predators in the environment.

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“…First, strategies that enhance a facultative pathogen's survival in the reservoir can also result in higher virulence within a host as a result of preadaptation or coincidental evolution. For example, antipredator adaptations in the reservoir environment could function as virulence factors within a host (Adiba et al 2010;Robino et al 2019). As a result, This is the author's accepted manuscript without copyediting, formatting, or final corrections.…”

Section: Modelmentioning

confidence: 99%

Virulence Evolution of Pathogens That Can Grow in Reservoir Environments

Pandey

Mideo

Platt

2022

The American Naturalist

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Many pathogens reside in environmental reservoirs within which they can reproduce and from which they can infect hosts. These facultative pathogens experience different selective pressures in host-associated environments and reservoir environments.Heterogeneous selective pressures have the potential to influence the virulence evolution of these pathogens. Previous research has examined how environmental transmission influences the selective pressures shaping the virulence of pathogens that cannot reproduce in environmental reservoirs, yet many pathogens of human, crop plants, and livestock can reproduce in these environments. We build on this work to examine how reproduction in reservoirs influences disease dynamics and virulence evolution in a simple facultative pathogen model. We use adaptive dynamics to examine the evolutionary dynamics of facultative pathogens under potential trade-offs between transmission and virulence, shedding and virulence, and reservoir persistence and virulence. We then perform critical function analysis to generalize the results independent of specific trade-off assumptions. We determine that diverse virulence strategies, sometimes resulting from evolutionary bistability or evolutionary branching conditions, are expected for facultative pathogens. Our findings motivate research establishing which trade-offs most strongly influence the virulence evolution of facultative pathogens.

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Resistance of the oyster pathogen Vibrio tasmaniensis LGP32 against grazing by Vannella sp. marine amoeba involves Vsm and CopA virulence factors

Cited by 10 publications

References 50 publications

Marine Bacteria Display Different Escape Mechanisms When Facing Their Protozoan Predators

Marine Bacteria Display Different Escape Mechanisms When Facing Their Protozoan Predators

Vibrio splendidus O‐antigen structure: a trade‐off between virulence to oysters and resistance to grazers

Virulence Evolution of Pathogens That Can Grow in Reservoir Environments

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