Crop pathogens have to adapt to diverse selective pressures such as varying cultural practices, new host plants or climate change. Quantitative traits of pathogenicity are expected to evolve in response to these factors and could be good proxies to assess pathogen fitness in agricultural ecosystems. This research aims to understand how plant pathogen life history traits respond to global changes including host resistance introduction, cultural practices and climate change. More specifically, we study a broad range of quantitative traits of pathogenicity in a biotrophic oomycete pathogen (the causal agent of grapevine downy mildew) and compare the aggressiveness of strains: (i) collected in abandoned versus conventional vineyard; (ii) resistant versus sensitive to fungicides; (iii) collected in resistant versus sensitive host populations. The overall hypothesis of our work is that intensive agricultural practices and the introduction of resistant host varieties would increase pathogen aggressiveness.

Related publications:

Delmas et al. (in prep) Adaptation of grapevine powdery mildew to partial plant resistance.

Delmas et al. (2017) Soft selective sweeps in fungicide resistance evolution: recurrent mutations without fitness costs in grapevine downy mildew. PDF, Dataset

Delmas et al. (2016) Adaptation of a plant pathogen to partial host resistance: selection for greater aggressiveness in grapevine downy mildew. PDF, Dataset, Press release (in french)

Delmas et al. (2014) Simultaneous quantification of sporangia and zoospores in a biotrophic oomycete with an automatic particle analyzer: disentangling dispersal and infection potentials. PDF