Identification and In Situ Distribution of a Fungal Gene Marker: The Mating Type Genes of the Black Truffle.

Truffles are ectomycorrhizal fungi harvested mainly in human managed agroforestry ecosystems. Truffle production in truffle orchards faces two important bottlenecks or challenges: the initiation of the sexual reproduction and the growth of the ascocarps during several months. The black Périgord truffle, Tuber melanosporum, is a heterothallic species and the mating type genes (MAT1-1 and M1T1-2) have been characterized. In this context, the unraveling of the T. melanosporum mating type strains distribution in truffle orchards is a critical starting point to provide new insights into its sexual reproduction. The aim of this chapter is to present the protocol used to characterize the T. melanosporum mating type present in a truffle orchard from ascocarps, hazel mycorrhizal root tips, and/or soil samples, by polymerase chain reactions using specific primers for those genes, but it can be adapted for other fungal species.