Influence of Edaphic Factors on Edible Ectomycorrhizal Mushrooms: New Hypotheses on Soil Nutrition and C Sinks Associated to Ectomycorrhizae and Soil Fauna Using the Tuber Brûlé Model

Fungi can strongly acidify their immediate soil environment and can cause a change in the equilibrium of soil carbonates. The Tuber melanosporum brule is an interesting biological model for studying soil reaction (pH) and decarbonation–recarbonation soil processes associated with ectomycorrhizal plants and soil fauna communities. Over the past 10 years ,we have observed that (1) a high concentration of active carbonate and exchangeable Ca2+ in the soil favors T. melanosporum fruiting body production and larger brules, (2) the amount of active carbonate is significantly higher and the total carbonate is significantly lower inside the T. melanosporum brule than outside the brule, (3) T. melanosporum ectomycorrhizae impact biodiversity and soil quality, and (4) the calciferous glands of Lumbricidae have an impact on soil reaction and carbonate availability in the brules. Here we propose new hypotheses on ectomycorrhizal fungal ecology, soil biology, and inorganic C soil sinks, suggesting that (1) the model that best explains the cause and effect of all brule observations is a feedback process; (2) this model assumes that T. melanosporum’s ability to modify soil properties has a direct impact on plant nutrition and degree of plant mycorrhization, and this hypothesis could have a considerable impact from the evolutionary standpoint of ectomycorrhizal fungi; and (3) the integrated action of T. melanosporum and/or other ectomycorrhizal fungal populations, and earthworms, could be of major importance in the cycling and sequestration of inorganic C in the soil.