Diversity of the bacterial hyperparasite Pasteuria penetrans in relation to root-knot nematodes (Meloidogyne spp.) control on Acacia holosericea

Pasteuria penetrans isolates sampled from different geographical areas were characterised both for the heterogeneity of the endospore surface using monoclonal antibodies and for the ability of spores to attach to different isolates of Meloidogyne spp. The efficacy of these different Pasteuria isolates as biological control agents was tested in a glasshouse experiment with M. incognita from Senegal on Acacia holosericea. The immunoprofiles divided the P. penetrans isolates broadly differently from the attachment tests. Isolate PP16 from Senegal was associated with better seedling development of M. incognita-inoculated A. holoceria than were other isolates. Substantial variation in root and shoot biomass was not related to the observed variation in spore attachment tests. The difficulties involved in obtaining consistent biological control with Pasteuria are discussed in relation to the high degree of variability of this bacterium.