The role of diffusible signals in the establishment of rhizobial and mycorrhizal symbioses.- Infection of Lotus japonicus roots by Mesorhizobium loti.-Signalling and re-structuring of the plant cell architecture in AM symbiosis.- Common pathways in legume and arbuscular mycorrhizal symbioses.- Signalling and communication in the actinorhizal symbioses.- Signalling in the cyanobacterial-plant symbioses.- Signalling in ectomycorrhizal symbiosis.- Signaling in the Epichlo? festucae - perennial ryegrass mutualistic symbiotic interaction.- Plant infection by biotrophic fungal and oomycete pathogens.- Compatibility in biotrophic plant-fungal interactions: Ustilago maydis and friends.- Compatible plant-root knot nematode interaction and parallels with symbiosis.