Local adaptation and population structure at a micro-geographical scale of a fungal parasite on its host plant


Claire Neema, UMR de Pathologie Végétale, INA-PG, 16 rue Claude Bernard, 75231 Paris Cedex 05, France.
Tel.: 33 (0)1 44 08 17 05; fax: 33 (0)1 44 08 16 31;
e-mail: neema@inapg.fr


Local adaptation, which has been detected for several wild pathosystems is influenced by gene flow and recombination. In this study, we investigate local adaptation and population structure at a fine scale in wild populations of a plant-pathogen fungus. We sampled hierarchically strains of Colletotrichum lindemuthianum in a wild population of its host. The analysis of AFLP patterns obtained for 86 strains indicated that: (i) many different haplotypes can be discriminated, although occurrence of recombination could not be shown; (ii) migration between adjacent plants seemed rare during the season; and (iii) neutral diversity is structured according to groups of plants and individual host plants. Furthermore, we tested for the occurrence of local adaptation using a cross-inoculation experiment. Our results showed local adaptation at the scale of the individual host plant. These results indicate that fine-scale dynamics has evolutionary consequences in this pathosystem.