ICOM1 Abstract

DIEZ, JESUS1, FRANCIS MARTIN2 & JOSE. L. MANJON1. 1Biologia Vegetal, Universidad de Alcala de Henares, 28871 Alcala de Henares, Spain. 2Microbiologie Forestiere, I.N.R.A., Centre de Nancy, 54280 Champenoux, France. - Biodiversity of the desert truffles associated with Tuberaria guttata in the Mediterranean Spanish vegetation. A "dehesa-like" vegetation exists in the Extremadura Region of Spain. This one comprises a grass land with some trees, mainly holm oaks (Quercus rotundifolia) and/or cork trees (Quercus suber). During the spring season, the local inhabitants collect desert truffles near the annual plant Tuberaria guttata. The desert truffles are known to form mycorrhizas with the Cistaceae. However, no genetic diversity studies have been reported for these fungi. The main objective of the present study is to assess the genetic biodiversity of the desert truffles in this region. Three different mycorrhizal fungal species were identified by studying morphological features of the fruiting bodies, by optical and scanner microscopy. They were Tuber asa, Terfezia arenaria and T. leptoderma, which form mycorrhizal communities with Tuberaria guttata in siliceous acid-sandy soils. The internal transcribed spacer (ITS) of the nuclear ribosomal DNA (rDNA) from fruiting bodies and isolates have been amplified by PCR. RADP and polymorphism of microsatellite rich DNA were also carried out. PCR-RFLP was very homogeneous within species. In contrast, RAPD and polymorphism of microsatellite rich regions were much larger. These data suggest that RAPD and polimorphism analysis of microsatellite rich DNA have a higher power of resolution for assaying the variability of these mycorrhizal communities.