Analysis of factors involved in fungal recognition responses to host-derived signals by arbuscular mycorrhizal fungi

SUMMARY An experimental model for the study of recognition responses by arbuscular mycorrhizal symbionts to host roots was validated by analysing the main factors which might affect such responses. Results showed that fungal responses to host-derived signals were unaffected by the degree of sterility of the system, host age and mycorrhizal status, symbiont age, or different chemical and physical characteristics of hydrophilic membranes. Use of dialysis membranes showed that the molecules putatively eliciting fungal responses weigh less than 500 Da. Utilization of the model for studies of developmental expression of proteins and genes in arbuscular mycorrhizal symbionts is examined.