Tuber melanosporum spread within sub-optimal climatic zones is controlled by fruiting triggers and not mycorrhiza survival

Tuber melanosporum is the most valuable of all cultivatable truffle species. Farming of this species spans every continent with the exception of Antarctica. Tuber aestivum (syn. T. uncinatum) and Tuber brumale are truffle species that have similar host plant preference and a similar affinity for calcareous soils as T. melanosporum, but occur over a broader geographic zone. The geographic limit of T. melanosporum is thought to be climatically dictated but it is not known whether this is due to an impact on mycorrhizal survival or climatically-derived fruiting triggers. Here, data is compiled from five cultivated research sites in the climatically sub-optimal conditions of the UK in order to address this question. Here we show:(i)Tuber melanosporum mycorrhiza can survive and grow in sub-optimal climatic conditions.(ii)It is climatically-derived fruiting triggers and not ectomycorrhiza survival that dictate the climatic preferences and geographic spread of T. melanosporum.(iii)Important climatic parameters for potential fruiting triggers are sunshine hours, summer rainfall and summer temperatures. The data presented here not only aid our understanding of the ecological parameters of T. melanosporum but also have a practical application for truffle cultivators in choosing suitable locations for a plantation