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Séminaire "Pesticides in agro-systems : Unintended effect of triazoles fungicides"

13H30-15H30
Salle -107M
Chrono-environnement, 16 Route de Gray, 25030 Besançon, France

PROGRAM

-  E. Snelders (Post-doctoral researcher - Laboratory of Genetics, Wageningen, The Netherlands)
Aspergillus fumigatus and triazole resistance : focusing on the ecological aspects and evolutionary genetics.

Eveline Snelders finished her PhD on azole resistance development in Aspergillus fumigatus in 2012 at the RadboudUMC in Nijmegen, the Netherlands with Prof Paul Verweij. She then continued with her degree as Medical Molecular Microbiologist also at the RadboudUMC in Nijmegen which she successfully finished in 2014. In January 2015 she started a Post-doc position at the Institute Pasteur, in the group of Prof Françoise Dromer where she worked on Cryptococcus. In 2016 she started on a personal 3 year grant (NWO VENI) in the laboratory of Prof. Bas Zwaan at the Laboratory of Genetics (WUR). After investigating the topic of antifungal resistance from a clinical point of view during her PhD, she is now also focusing on the ecological aspects and evolutionary genetics.

-  S. Rocchi (PhD – CHRU Besançon/ UMR Chrono-Environment, Besançon, France)
Triazole-resistant Aspergillus fumigatus in Franche-Comté : from the fields to the hospital

In 2012, the mycology team at the Besançon University Hospital described the first French case of invasive aspergillosis (AI) due to a resistant strain in a farmer using triazole fungicides. A second occurred in a woodworker, where triazoles are also used to control wood-eating filamentous fungi. These clinical cases led us to study the presence of these strains in different types of professional environments (cereals crops, sawmills, market gardens). The number of clinical cases involving resistant strains is increasing at the University Hospital of Besançon, particularly in cystic fibrosis patients (16% of patients with A. fumigatus-positive cultures in 2017). And since 2015, the number of resistant isolates obtained in air of corridors has also increased. Currently, 230 resistant A. fumigatus have been characterized in our laboratory : location, origin and date of sampling, resistance phenotype, sequencing of the main gene involved in triazole resistance, genotyping.

-  Fabrice Martn-Laurent (Director of Research, INRA – AgroSup Dijon, UMR Agroécologie, Dijon, France)
Fate of tebuconazole in an arable soil and ecotoxicological impact of this fungicide on soil bacterial communities.

Triazole fungicides are frequently used to protect crops from fungal diseases. Although being efficient, they are relatively recalcitrant to biodegradation and residues persist in the soil from where they can be dispersed and where they may impact in-soil living organisms, including soil microorganisms that are supporting numerous ecosystemic functions. This talk will present results showing on the one hand the fate and the transformation of tebuconazole in an arable soil and on the other hand, the ecotoxicological effect of tebuconazole and its transformation products on the abundance, composition and diversity of soil bacterial communities.

-  Clémentine Fritsch (Researcher, CNRS – UMR Chrono-Environment, Besançon, France)
Residues of currently used pesticides in soils and non target wildlife : a silent threat ?

Within the framework of RESCAPE research program, we investigate exposure to currently used pesticides (CUPs) of earthworms, carabid beetles and small mammals. Soils and animals have been sampled in cereal crops and grasslands cultivated under conventional and organic farming as well as hedgerows in agricultural landscapes over a long term environmental research site in France. Multi-residue analyses of CUPs show an ubiquity of contamination by CUP mixtures since pesticides have detected in samples from both treated and untreated habitats, with high proportion of samples containing at least one pesticide (more than 75% for beetles, 92% for earthworms and 100% for soils and small mammals). Mixtures of at least one insecticide, one herbicide and one fungicide were found in most of soil and non-target wildlife samples. Predicted Environmental Concentrations in soils and toxic thresholds for earthworms were exceeded in several cases, notably fungicides. Further, fungicides are of particular concerns for both high occurrence of detection in all taxa and high levels of concentration, notably azoles such as epoxiconazole, cyproconazole, and metconazole. Our results strongly suggest that the use of CUPs cause contamination of target and non-target soils and beneficial organisms that can negatively affect agro-ecosystem functioning, biodiversity and ecosystem services.

-  Chloé Godeau (PhD student, UMR Chrono-Environment, Besançon, France)

The environmental source of resistance to azole molecules in Aspergillus fumigatus has been widely described. Avoid the use of azole molecules both in agriculture and in the wood industry seems not feasible in terms of yield loss. One of the research tracks to restrain the phenomenon of resistance appearance would be to limit the unintended effect of the fungicide excess in the environment. Biodegradable chemical molecules named cyclodextrins could limit the contact between azole molecules excess and Aspergillus fumigatus strains without reducing the treatment effectiveness.

Contact : Steffi Rocchi

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