Publication Date:
2016-08-16
Description:
Environmental factors such as temperature strongly impact microbial communities. In the current context of global warming, it is therefore crucial to understand the effects of these factors on human, animal, or plant pathogens. Here, we used a common-garden experiment to analyze the thermal responses of three life-history traits (latent period, lesion growth, spore number) in isolates of the potato late blight pathogen Phytophthora infestans from different climatic zones. We also used a fitness index (FI) aggregating these traits into a single parameter. The experiments revealed patterns of local adaptation to temperature for several traits and for the FI, both between populations and within clonal lineages. Local adaptation to temperature could result from selection for increased survival between epidemics, when isolates are exposed to more extreme climatic conditions than during epidemics. We also showed different thermal responses among two clonal lineages sympatric in western Europe, with lower performances of lineage 13_A2 compared to 6_A1, especially at low temperatures. These data therefore stress the importance of thermal adaptation in a widespread, invasive pathogen, where adaptation is usually considered almost exclusively with respect to host plants. This must now be taken into account to explain, and possibly predict, the global distribution of specific lineages and their epidemic potential. We used a common-garden experiment to analyse the thermal responses of three life-history traits (latent period, lesion growth, and spore number) in isolates of the potato late blight pathogen Phytophthora infestans from different climatic zones. The experiments revealed patterns of local adaptation to temperature, both between populations and within clonal lineages. We also showed differential thermal response curves for two clonal lineages sympatric in western Europe, 6_A1 and 13_A2. The consequences for invasive potential and pathogen distribution in a context of changing temperatures are discussed.
Electronic ISSN:
2045-7758
Topics:
Biology
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