Certainties and uncertainties about the life cycle of the P,rigord black truffle (Tuber melanosporum Vittad.)

Context The hypogeous sporophores of several Tuber species, renowned for their aromatic and gustatory qualities, are widely commercialized. One of the most valuable species is Tuber melanosporum Vittad., the P,rigord black truffle also known as the black diamond. However, many aspects of T. melanosporum life cycle remain unsolved. Aims In this work, we examine past and recent findings on the life cycle of T. melanosporum, currently regarded as a model system for Tuber species, with the view of highlighting aspects of its life cycle which remain unsolved. Results Several aspects of its life cycle have recently been elucidated (i.e. characterization of two mating type genes, heterothallism, prevalence of sexual reproduction on vegetative propagation, exclusion of one mating type by its opposite on ectomycorrhizas, dependency of ascocarps on their host for carbon allocation), while others remain unaddressed. Conclusion Numerous additional aspects of the T. melanosporum life cycle remain unsolved, such as exclusion or competition mechanisms between ectomycorrhizal mating types, factors involved in ascocarp initiation, the nature of the connection linking ascocarps and mycorrhizas and atmospheric nitrogen fixation.