Genetic signatures of variation in population size in a native fungal pathogen after the recent intensive plantation of its host tree

Historical fluctuations in forests’ distribution driven by past climate changes and anthropogenic activities can have large impacts on the demographic history of pathogens that have a long co-evolution history with these host trees. Using a population genetic approach, we investigated that hypothesis by reconstructing the demographic history of Armillaria ostoyae, one of the major pathogens of the maritime pine (Pinus pinaster), in the largest monospecific pine planted forest in Europe (south-western France). Genetic structure analyses and approximate Bayesian computation approaches revealed that a single pathogen population underwent a severe reduction in effective size (12 times lower) 1080–2080 generations ago, followed by an expansion (4 times higher) during the last 4 generations. These results are consistent with the history of the maritime pine forest in the region characterized by a strong recession during the last glaciation (~19 000 years ago) and massive plantations during the second half of the nineteenth century. Results suggest that recent and intensive plantations of a host tree population have offered the opportunity for a rapid spread and adaptation of their pathogens

Recherche de l'impact de la sylviculture intensive sur l'expression des maladies racinaires: cas particulier de l'armillaire (A. ostoyae) en foret des Landes de Gascogne

National audienc

Etude in situ des principales étapes du cycle infectieux de l'armillaire (Armillaria ostoyae) du pin maritime en forêt de Gascogne

National audienc

A method to screen Trichoderma isolates against soil sclerotial fungi and armillaria root rot

International audienc

Enzyme equipment in the Armillaria ostoyae/Pinus pinaster interaction : relation to host aggression

International audienc

Gestion durable et santé de la forêt aquitaine de pin maritime

International audienc

Epidémiologie

chap. 11National audienc

Sylviculture intensive du pin maritime et risques phytosanitaires

National audienc

Identification and partial characterization of an extracellular manganese-dependent peroxidase in Armillaria ostoyae and <em>Armillaria mellea</em>

National audienceAbstract Laccase and manganese-dependent peroxidase (Mn peroxidase) activities were detected in the culture media of Armillaria ostoyae and A. mellea. Mn peroxidase was produced in significantly higher quantity by the A. ostoyae isolates and was purified by chromatography from one isolate of this species. Some properties of the purified enzyme were examined (absorption spectrum, H2O2 and MnSO4 optimal concentrations, pH optimum and lactate stimulation). Enzymes of potential importance in the lignin degradation (especially Mn peroxidase) by Armillaria sp. are compared to those of other root-rotting fungi. The possible role of Mn peroxidase in modulating the pathogenicity of Armillaria sp. is discussed

Root and butt rots of forest trees

International audienc