International Symposium on Cereal Leaf Blights 2019 | University College Dublin, Ireland | 22-24 May 2019

How mixed infection impacts the transmission of the wheat pathogen Z. tritici?

Alessio Bernasconi
ETH Zurich

Marcello Zala
ETH Zurich

Bruce McDonald
ETH Zurich

Andrea Sánchez-Vallet*
ETH Zurich

Poster Presentation
Evolution and Population Biology

Atrium, UCD O'Brien centre for Science
Poster 4

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Natural infections are frequently produced by several strains that co-infect simultaneously the same host. Mixed infections affect the outcome of the infection, the epidemiology and transmissibility of the pathogen. However, so far, only few studies have investigated how mixed infections affect the infection dynamics and the evolution of virulence of fungal pathogens. This is also the case forthe wheat fungal pathogen Zymoseptoria tritici. Z. triticiis so diverse that even in single lesions multiple strains co-exist and produce pycnidia. Our recent studieshave shown that competition between strains leads tochanges in the overall virulence and to a reduction in the expected number of pycnidia produced. In serial passage experiments, we demonstrated that one strain outcompeted the others. We observed that the outcome of the competition was dependent on the cultivar and not on the virulence phenotype of the strain. We suggest that the adaptation of each strain to a specific cultivar increased its competition capacity and provides an advantage to the strain to be successfully transmitted in mixed infections.