Genetic Divergence and Chemotype Diversity in the Fusarium Head Blight Pathogen Fusarium poae
Adriaan Vanheule,
Marthe De Boevre,
Antonio Moretti,
Jonathan Scauflaire,
Françoise Munaut,
Sarah De Saeger,
Boris Bekaert,
Geert Haesaert,
Cees Waalwijk,
Theo van der Lee,
Kris Audenaert
Affiliations
Adriaan Vanheule
Department of Applied Biosciences, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium
Marthe De Boevre
Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, 9000 Ghent, Belgium
Antonio Moretti
Institute of Sciences of Food Production, National Research Council, 70126 Bari, Italy
Jonathan Scauflaire
Applied Microbiology, Earth and Life Institute, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
Françoise Munaut
Applied Microbiology, Earth and Life Institute, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
Sarah De Saeger
Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, 9000 Ghent, Belgium
Boris Bekaert
Department of Applied Biosciences, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium
Geert Haesaert
Department of Applied Biosciences, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium
Cees Waalwijk
Wageningen University and Research Centre, 6708PB Wageningen, The Netherlands
Theo van der Lee
Wageningen University and Research Centre, 6708PB Wageningen, The Netherlands
Kris Audenaert
Laboratory of Applied Mycology and Phenomics, Department of Applied Biosciences, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium
Fusarium head blight is a disease caused by a complex of Fusarium species. F. poae is omnipresent throughout Europe in spite of its low virulence. In this study, we assessed a geographically diverse collection of F. poae isolates for its genetic diversity using AFLP (Amplified Fragment Length Polymorphism). Furthermore, studying the mating type locus and chromosomal insertions, we identified hallmarks of both sexual recombination and clonal spread of successful genotypes in the population. Despite the large genetic variation found, all F. poae isolates possess the nivalenol chemotype based on Tri7 sequence analysis. Nevertheless, Tri gene clusters showed two layers of genetic variability. Firstly, the Tri1 locus was highly variable with mostly synonymous mutations and mutations in introns pointing to a strong purifying selection pressure. Secondly, in a subset of isolates, the main trichothecene gene cluster was invaded by a transposable element between Tri5 and Tri6. To investigate the impact of these variations on the phenotypic chemotype, mycotoxin production was assessed on artificial medium. Complex blends of type A and type B trichothecenes were produced but neither genetic variability in the Tri genes nor variability in the genome or geography accounted for the divergence in trichothecene production. In view of its complex chemotype, it will be of utmost interest to uncover the role of trichothecenes in virulence, spread and survival of F. poae.
