Mycorrhizal status of Phlebopus bruchii (Boletaceae): does it form ectomycorrhizas with Fagara coco (Rutaceae)?

NOUHRA, E. C. URCELAY, A. BECERRA & L. DOMÍNGUEZ

SYMBIOSIS

Año: 2008

0334-5114

Fagara coco (Gill.) Engl., a native tree in the mountains of Central Argentina, generally grows associated with Phlebopus bruchii (Speg.) Heineman & Rammeloo. The association with this edible bolete has been considered an ectomycorrhizal symbiosis. To test the hypothesis of their co-occurrence as mutualistic partners, we studied mycorrhizal colonization in roots from natural stands and roots inoculated with spores of P. bruchii in a greenhouse and pure culture experiments. No ectomycorrhizal (ECM) colonization were detected. Instead, roots collected from the field were colonized by arbuscular mycorrhizal (AM) fungi showing Arum-type structures. The percentage of AM mycorrhizal colonization varied among seasons, being higher in autumn (March, April and May). Spores of ten Glomalean taxa were isolated from the rhizosphere. Based on the results achieved, we believe that Phlebopus bruchii, is an exception to the mycorrhizal habit of most Boletales.