Molecular Characterization of Some Truffle Species

Summary

In order to attempt the molecular characterization of ectomycorrhizal Ascomycetous fungi eight Tuber species ( Tuber magnatum, Tuber melanosporum, Tuber aestivum, Tuber rufum, Tuber ferrugineum, Tuber macrosporum, Tuber brumale and Tuber borchii) were analyzed at the DNA and protein levels. DNA was extracted from truffle fruitbodies and digested with EcoRI to perform Southern analysis. Ribosomal DNA was used as a probe, and gave rise to highly polymorphic patterns. Small differences were noted even between two samples of T. magnatum harvested in different geographical areas. AcDNA library of T. magnatum was prepared in order to obtain truffle homologous probes. SDS-PAGE analysis was performed on total protein extracts leading to similar conclusions: patterns are specific for each truffle, with the exception of T. magnatum for which small differences between the two samples previously described were observed, and no difference was noticed among the patterns of proteins extracted from morphologically different parts of the same fruitbody. Isoelectric focusing (IEF) was carried out on six protein extracts (from T. borchii, T. melanosporum, T. magnatum, T. uncinatum and two samples of T aestivum,), giving rise to specific patterns for each truffle. Two-dimensional analysis (IEF followed by SDS-PAGE) of truffle total proteins could be very helpful in differentiating between similar species.

These molecular approaches have proved to be particularly useful in discriminating among the different truffle species and it is worth verifying whether the same techniques can also be adopted to identify these symbiotic fungi in ectomycorrhizae.