Morphological characterisation of the mycorrhizal symbiosis between Tuberaria guttata (L.) Fourr and Terfezia arenaria (Moris) Trappe

Desert truffles are hypogeous fungi, with an important role in the folklore and cuisine of many countries. They are mycorrhizal fungi belonging to the Ascomycetes and forming symbiotic associations with several species of the family Cistaceae. The plant-desert truffle association has been the subject of numerous studies. The main purpose of the present research was to characterise the mycorrhizal system between Tuberaria guttata (L.) Fourr and Terfezia arenaria (Moris) Trappe. Plants of T. guttata were grown in pots under greenhouse conditions. They were inoculated in vivo with a solution containing spores of T. arenaria. The mycorrhizal level was assessed after root staining. T. guttata roots were also collected from littoral dunes in northeastern Algeria in order to compare the mycorrhizal status under both natural and in vivo conditions. Two principal ectomycorrhizal morphotypes were observed: branched mycorrhizae and club-shaped mycorrhizae. Root staining and observations of semi-thin sections showed that the in vivo produced roots had an ectomycorrhiza with Hartig net and extracellular hyphae more or less organised in a “real” sheath. The less-developed sheath was seen in the branched mycorhhiza and the well-developed one in the club-shaped mycorrhiza. This is the first report of a sheathing ectomycorrhiza formed by a desert truffle species associated with herbaceous plant.