4PV - Unité de Pathologie Végétale (Domaine Saint Maurice Unité de Recherche de Pathologie Végétale 67, allée des chênes CS 60094 F84143 Montfavet Cedex - France)
Abstract : Understanding the causes of population subdivision is of fundamental importance, as studying barriers to gene flow between populations may reveal key aspects of the process of adaptive divergence and, for pathogens, may help forecasting disease emergence and implementing sound management strategies. Here, we investigated population subdivision in the multi-host fungus Botrytis cinerea, based on comprehensive multiyear sampling on different hosts in three French regions. Analyses revealed a weak association between population structure and geography, but a clear differentiation according to the host plant of origin. This was consistent with adaptation to hosts, but the distribution of inferred genetic clusters and the frequency of admixed individuals indicated a lack of strict host-specificity. Differentiation between individuals collected in the greenhouse (on Solanum) and outdoor (on Vitis and Rubus) was stronger than that observed between individuals from the two outdoor hosts, probably reflecting an additional isolating effect associated with the cropping system. Three genetic clusters coexisted on Vitis, but did not persist over time. Linkage disequilibrium analysis indicated that outdoor populations were regularly recombining, whereas clonality was predominant in the greenhouse. Our findings open up new perspectives for disease control by managing plant debris in outdoor conditions, and reinforcing prophylactic measures indoor.
Anne Sophie A. S. Walker, Pierre Gladieux, Véronique Decognet, Marc Fermaud, Johann J. Confais, et al.. Population structure and temporal maintenance of the multihost fungal pathogen Botrytis cinerea: causes and implications for disease management.. Environmental Microbiology, Society for Applied Microbiology and Wiley-Blackwell, 2015, 17 (4), pp.1261-1274. ⟨10.1111/1462-2920.12563⟩. ⟨hal-02638009⟩