Can parasites adapt to pollutants? A multigenerational experiment with a Daphnia × Metschnikowia model system exposed to the fungicide tebuconazole.
Aquat Toxicol
; 226: 105584, 2020 Sep.
Article
en En
| MEDLINE
| ID: mdl-32795838
ABSTRACT
There is increasing evidence about negative effects of fungicides on non-target organisms, including parasitic species, which are key elements in food webs. Previous experiments showed that environmentally relevant concentrations of fungicide tebuconazole are toxic to the microparasite Metschnikowia bicuspidata, a yeast species that infects the planktonic crustacean Daphnia spp. However, due to their short-term nature, this and other experimental studies were not able to test if parasites could potentially adapt to these contaminants. Here, we tested if M. bicuspidata parasite can adapt to tebuconazole selective pressure. Infected D. magna lineages were reared under control conditions (no tebuconazole) and environmentally realistic tebuconazole concentrations, for four generations, and their performance was compared in a follow-up reciprocal assay. Additionally, we assessed whether the observed effects were transient (phenotypic) or permanent (genetic), by reassessing parasite fitness after the removal of selective pressure. Parasite fitness was negatively affected throughout the multigenerational exposure to the fungicide prevalence of infection and spore load decreased, whereas host longevity increased, in comparison to control (naive) parasite lineages. In a follow-up reciprocal assay, tebuconazole-conditioned (TEB) lineages performed worse than naive parasite lineages, both in treatments without and with tebuconazole, confirming the cumulative negative effect of tebuconazole. The underperformance of TEB lineages was rapidly reversed after removing the influence of the selective pressure (tebuconazole), demonstrating that the costs of prolonged exposure to tebuconazole were phenotypic and transient. The microparasitic yeast M. bicuspidata did not reveal potential for rapid evolution to an anthropogenic selective pressure; instead, the long-term exposure to tebuconazole was hazardous to this non-target species. These findings highlight the potential environmental risks of azole fungicides on non-target parasitic fungi. The underperformance of these microbes and their inability to adapt to such stressors can interfere with the key processes where they intervene. Further research is needed to rank fungicides based on the hazard to non-target fungi (parasites, but also symbionts and decomposers), towards more effective management and protective legislation.
Palabras clave
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Triazoles
/
Contaminantes Químicos del Agua
/
Daphnia
/
Metschnikowia
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Fungicidas Industriales
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Modelos Biológicos
Tipo de estudio:
Prognostic_studies
/
Risk_factors_studies
Límite:
Animals
Idioma:
En
Revista:
Aquat Toxicol
Asunto de la revista:
BIOLOGIA
/
TOXICOLOGIA
Año:
2020
Tipo del documento:
Article