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3. Doktoritööd

Selle kollektsiooni püsiv URIhttp://hdl.handle.net/10492/2490

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Sirvi 3. Doktoritööd Autor "Andersson, Björn (opponent)" järgi

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    Phenotypic traits influencing changes in potato late blight pathogen Phytophthora infestans populations in Europe
    (Estonian University of Life Sciences, 2025) Puidet, Britt; Mänd, Marika (advisor); Koppel, Mati (advisor); Kiiker, Riinu (advisor); Institute of Agricultural and Environmental Sciences; Andersson, Björn (opponent)
    ABSTRACT. Potato late blight, caused by Phytophthora infestans, remains a substantial threat to global food security. European P. infestans populations are generally divided into Northern (genetically diverse) and Western (mainly clonal) populations. However, new genotypes have recently emerged and successfully established themselves in Northern Europe. Additionally, new strains that are more aggressive and more virulent or exhibit fungicide sensitivity to widely used active ingredients emerge frequently. The main objectives of this thesis were to study the drivers of new invasive lineages of P. infestans in Europe and the reason behind the shift in Northern European populations. Samples were collected from potato plants from conventional production fields, organic fields and trap nurseries in Estonia, Denmark, Norway, the UK, and France in ten growing seasons (between 2005-¬2022). DNA acquired from all the samples was genotyped through simple sequence repeat analysis. Phenotypic experiments were performed for samples collected in 2016 and 2017 and involved testing the isolates’ fungicide sensitivity to active ingredients widely used in Europe and evaluating their virulence to assess the ability of P. infestans to damage potato plants. Various population genetic indices were calculated to characterise the genetic diversity and dynamics of the pathogen in Estonia. Results showed that the Western European genotype EU_37_A2 exhibits fluazinam resistance, likely aiding its invasiveness. Genotype EU_41_A2 has successfully been established in Northern Europe, possibly due to higher virulence combined with other fitness traits or changes in environmental conditions not examined in this study. Substantial genetic and genotypic diversity persists in Estonia, suggesting a high likelihood of random mating. Still, monitoring results showed introductions of clonal lineages to the country, which creates a potential risk for future establishment. Our findings underscore the importance of continuous pathogen population monitoring to enable timely adjustments in control strategies.