Long-distance wind-dispersal of spores in a fungal plant pathogen: estimation of anisotropic dispersal kernels from an extensive field experiment.
2014
Rieux, Adrien | Soubeyrand, Samuel, S. | Bonnot, Francois | Klein, Etienne, E. | Ngando, Josue E | Mehl, Andreas | Ravigné, Virginie | Carlier, Jean | de Lapeyre de Bellaire, Luc | Biologie et Génétique des Interactions Plante-Parasite (UMR BGPI) ; Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro) | Biostatistique et Processus Spatiaux (BioSP) ; Institut National de la Recherche Agronomique (INRA) | Biologie et Génétique des interactions Plantes-parasites pour la Protection Intégrée ; Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro) | African Center for Research on Bananas and Plantains = Centre Africain de Recherches sur Bananiers et Plantains (CARBAP) | Bayer Pharma AG [Berlin] | Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad) | CIFRE doctoral fellowship from Bayer CropScience; Agence Nationale de la Recherche et de la Technologie [ANRT-123/2008]; Agence Nationale de la Recherche [ANR 07-BDIV-003/Emerfundis, ANR 09-BLAN-0145-01/EMILE]; Europaid contract [ATF/UE-No146-762/786/798/801]; European Research Council (ERC) [260801]
International audience
Mostrar más [+] Menos [-]Inglés. Given its biological significance, determining the dispersal kernel (i.e., the distribution of dispersal distances) of spore-producing pathogens is essential. Here, we report two field experiments designed to measure disease gradients caused by sexually- and asexually-produced spores of the wind-dispersed banana plant fungus Mycosphaerella fijiensis. Gradients were measured during a single generation and over 272 traps installed up to 1000 m along eight directions radiating from a traceable source of inoculum composed of fungicide-resistant strains. We adjusted several kernels differing in the shape of their tail and tested for two types of anisotropy. Contrasting dispersal kernels were observed between the two types of spores. For sexual spores (ascospores), we characterized both a steep gradient in the first few metres in all directions and rare long-distance dispersal (LDD) events up to 1000 m from the source in two directions. A heavy-tailed kernel best fitted the disease gradient. Although ascospores distributed evenly in all directions, average dispersal distance was greater in two different directions without obvious correlation with wind patterns. For asexual spores (conidia), few dispersal events occurred outside of the source plot. A gradient up to 12.5 m from the source was observed in one direction only. Accordingly, a thin-tailed kernel best fitted the disease gradient, and anisotropy in both density and distance was correlated with averaged daily wind gust. We discuss the validity of our results as well as their implications in terms of disease diffusion and management strategy.
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