Interaction between arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing fungi. Effect on AMF hyphal growth and alkaline phosphatase activity

DELLA MONICA I,; PEÑA R,; SCERVINO J.M

Belo Horizonte, Minas Gerais, Brazil

Congreso; 6th INTERNATIONAL CONFERENCE ON MYCORRHIZA (ICOM6); 2009

International Mycorrhiza Society

Phosphorus (P) is one of the main nutrients. It occurs mainly as inorganic phosphate (iP) and as organic phosphate (oP) derivatives, unavailable to plants. iP is converted into plant-available forms by some saprophytic fungi (SF). Arbuscular mycorrhizal fungi (AMF) produce alkaline phosphatase enzymes (AP) that solubilize oP sources and improve nutrient absorption by plants by increasing the absorptive surface area of the roots. Exudates of some SF are considered germination modulators, since they either stimulate or inhibit hyphal growth, depending on their concentrations. In this work, we tested the effect of Talaromyces flavus exudates on Gigaspora rosea in vitro by studying the interaction between SF and AMF. The 1-3% and 0.5-1% SF exudate concentrations increased the hyphal length and the number of branches respectively, suggesting the presence of substances that improve the growth and ramification of the AMF mycelia in the exudates of SF. We also evaluated the effect of T. flavus on the hyphal AP of Glomus intraradices in green-house experiments. The AP activity percentage was higher in the presence of T. flavus with iP amendment. The results show that the presence of iP produces changes in T. flavus exudates that positively influence the activity of AP of G. intraradices.