Morphological characterization of molecular-typed Tuber magnatum ectomycorrhizae

Recent reports of discrepancies between the morphological and molecular-based characterization of Tuber Magnatum ectomycorrhizae suggest misleading morphological typing of these structures. This study reports a new morphological and anatomical description of T magnatum ectomycorrhizae at different development stages using nursery-inoculated host plants. Both ascocarps, used as spore donors in the inoculation process, and the resulting ectomycorrhizae were first checked by single-step PCR analysis using a T magnatum species-specific ITS primer pair. Direct sequence analysis of the entire ITS1-5.8S-ITS2 fragment of DNA from mycorrhizal pools demonstrated the purity of the samples processed. Thus, the validity of the criteria reported here for the morphological identification of T magnatum symbiotic structures is supported by molecular analysis. When diagnostic morphological traits appear only occasionally, as a result of ageing or of particular edaphic conditions, only molecular markers such as the species-specific ITS primers designed here ensure reliable typing of T magnatum mycorrhizae for the purpose of controlling and/or certifying mycorrhizal plants present on the market.