High Variability in Infection Mechanisms and Host Responses: A Review of Functional Genomic Studies of Amphibian Chytridiomycosis

Zamudio, Kelly R.; McDonald, Cait A.; Belasen, Anat M.

doi:10.1655/0018-0831-76.2.189

Cited by 25 publications

(34 citation statements)

References 87 publications

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“…Chytridiomycosis threatens amphibian populations worldwide, however, disease risk varies greatly depending on a myriad of factors, including Bd lineage (12,13,16,24). While several studies have characterized the infection response of different amphibian species (21,(28)(29)(30)(31)(32)(33)(34)(35), our work contributes to identify Bd's functional machinery driving invasion and disease dynamics in a wide amphibian host range.…”

Section: Discussionmentioning

confidence: 99%

“…The copyright holder for this preprint this version posted December 1, 2021. ; https://doi.org/10.1101/2021.11.29.470466 doi: bioRxiv preprint multiple strategies to avoid or control disease progression, including skin microbiome interactions, immune system activation, and behavioral traits to reduce exposure (see review (23)). Not surprisingly, Bd infection outcome is highly variable across amphibian species and both biotic and abiotic context-dependent (24).…”

Section: Introductionmentioning

confidence: 99%

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Panzootic chytrid fungus exploits diverse amphibian host environments through plastic infection strategies

Torres‐Sánchez

Villate

McGrath-Blaser

et al. 2021

Preprint

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While many pathogens are limited to a single host, others can jump from host to host, which likely contributes to the emergence of infectious diseases. Despite this threat to biodiversity, traits associated with overcoming eco-evolutionary barriers to achieve host niche expansions are not well understood. Here, we examined the case of Batrachochytrium dendrobatidis (Bd), a multi-host pathogen that infects the skin of hundreds of amphibian species worldwide. To uncover functional machinery driving multi-host invasion, we analyzed Bd transcriptomic landscapes across 14 amphibian hosts and inferred the origin and evolutionary history of pathogenic genes under a phylogenetic framework comprising 12 other early-divergent zoosporic fungi. Our results not only revealed a conserved basal genetic machinery, but also highlighted the ability of Bd to display plastic infection strategies when challenged under suboptimal host environments. We found that genes related to amphibian skin exploitation have arisen mainly via gene duplications. We argue that plastic gene expression can drive variation in Bd lifecycles with different mode and tempo of development. Our findings support the idea that host skin environments exert contrasting selective pressures, such that gene expression plasticity constitutes one of the evolutionary keys leading to the success of this panzootic multi-host pathogen.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Panzootic chytrid fungus exploits diverse amphibian host environments through plastic infection strategies

Torres‐Sánchez

Villate

McGrath-Blaser

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…Survivors to Bsal exposures were characterized by the absence of infections (see Supporting Information dataset), indicating that the individuals effectively mounted an immune response to both pathogens. Although we did not quantify any immune parameters in this study, we expect that earlier exposure to Bd , variation in skin microbiomes or host genotypes are part of the systemic immune responses involved in this process (Rollins‐Smith, 2020; Zamudio et al, 2020). For example, anurans exposed to Bd have shown that immunogenetic responses are diverse and can range from immune dysregulation to immunosuppression (Grogan et al, 2018; Rollins‐Smith, 2020; Zamudio et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

Preparing for invasion: Assessing risk of infection by chytrid fungi in southeastern plethodontid salamanders

et al. 2020

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Understanding the responses of naïve communities to the invasion of multihost pathogens requires accurate estimates of susceptibility across taxa. In the Americas, the likely emergence of a second amphibian pathogenic fungus (Batrachochytrium salamandrivorans, Bsal) calls for new ways of prioritizing disease mitigation among species due to the high diversity of naïve hosts with priorB. dendrobatidis(Bd) infections. Here, we applied the concept of pathogenic potential to quantify the virulence of chytrid fungi on naïve amphibians and evaluate species for conservation efforts in the event of an outbreak. The benefit of this measure is that it combines and summarizes the variation in disease effects into a single numerical index, allowing for comparisons across species, populations or groups of individuals that may inherently exhibit differences in susceptibility. As a proof of concept, we obtained standardized responses of disease severity by performing experimental infections withBsalon five plethodontid salamanders from southeastern United States. Four out of five species carried natural infections ofBdat the start of the experiments. We showed thatBsalexhibited its highest value of pathogenic potential in a species that is already declining (Desmognathus auriculatus). We find that this index provides additional information beyond the standard measures of disease prevalence, intensity, and mortality, because it leveraged these disease parameters within each categorical group. Scientists and practitioners could use this measure to justify research, funding, trade, or conservation measures.

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“…Where the fungus became endemic, some amphibian hosts have evolved effective defenses against it including secretion of antimicrobial peptides (Rollins-Smith et al 2005 ; Woodhams et al 2007 ), adaptive immune responses (Rollins-Smith 2020 ; Zamudio et al 2020 ), and commensal bacteria that mitigate fungal effects (Harris et al, 2006 ). Bd has been associated mostly with declines in anurans, while Bsal’s effects so far seem limited to urodeles (Farrer 2019 ).…”

Section: Species Conceptsmentioning

confidence: 99%

Early-diverging fungal phyla: taxonomy, species concept, ecology, distribution, anthropogenic impact, and novel phylogenetic proposals

et al. 2021

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The increasing number of new fungal species described from all over the world along with the use of genetics to define taxa, has dramatically changed the classification system of early-diverging fungi over the past several decades. The number of phyla established for non-Dikarya fungi has increased from 2 to 17. However, to date, both the classification and phylogeny of the basal fungi are still unresolved. In this article, we review the recent taxonomy of the basal fungi and re-evaluate the relationships among early-diverging lineages of fungal phyla. We also provide information on the ecology and distribution in Mucoromycota and highlight the impact of chytrids on amphibian populations. Species concepts in Chytridiomycota, Aphelidiomycota, Rozellomycota, Neocallimastigomycota are discussed in this paper. To preserve the current application of the genus Nephridiophaga (Chytridiomycota: Nephridiophagales), a new type species, Nephridiophaga blattellae, is proposed.

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High Variability in Infection Mechanisms and Host Responses: A Review of Functional Genomic Studies of Amphibian Chytridiomycosis

Cited by 25 publications

References 87 publications

Panzootic chytrid fungus exploits diverse amphibian host environments through plastic infection strategies

Panzootic chytrid fungus exploits diverse amphibian host environments through plastic infection strategies

Preparing for invasion: Assessing risk of infection by chytrid fungi in southeastern plethodontid salamanders

Early-diverging fungal phyla: taxonomy, species concept, ecology, distribution, anthropogenic impact, and novel phylogenetic proposals

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