Desert truffles have become an alternative agricultural crop in semiarid areas of the Iberian Peninsula due to their much appreciated edible value and their low water requirements for cultivation. Although most studies related to desert truffle production point to the sole importance of precipitation, this work is the first systematic study carried out to characterize whether other important agroclimatic parameters, for example reference evapotranspiration, soil water potential, relative air humidity %, aridity index or air vapour pressure deficit, may have an impact on a desert truffle production in an orchard with mycorrhizal plants of Helianthemum almeriense × Terfezia claveryi for 15 years from the plantation. The results show for the first time that T. claveryi production has two key periods, during its annual cycle: autumn (September to October) and spring (end of March). The aridity index and soil water potential seem to be the most manageable parameters in the field and can be easily controlled by applying irrigation during the abovementioned periods. Agroclimatic parameters can influence the final crop a long time before the desert truffle fruiting season contrary to what happens with other edible mycorrhizal mushrooms. Four different models to manage desert truffle plantations are proposed based on these agroclimatic parameters in order to optimize and stabilize carpophore fructifications over the years.

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 Desert truffles are edible hypogeous fungi forming ectendomycorrhizal symbiosis with plants of Cistaceae family. Knowledge about the reproductive modes of these fungi and the molecular mechanisms driving the ectendomycorrhizal interaction is lacking.  Genomes of the highly appreciated edible desert truffles, Terfezia claveryi Chatin and Tirmania nivea Trappe, have been sequenced and compared to other Pezizomycetes. Transcriptomes of T. claveryi x Heliantemum almeriense mycorrhiza from well-watered and drought-stressed plants, when intracellular colonizations is promoted, were investigated.  We have identified the fungal genes related to sexual reproduction in desert truffles and desert truffles specific genomic and secretomic features with respect to other Pezizomycetes, such as the expansion of a large set of gene families with unknown Pfam domains and a number of species or desert truffle-specific small secreted proteins differentially regulated in symbiosis. A core set of plant genes, including carbohydrate, lipid metabolism and defence related genes, differentially expressed in mycorrhiza under both conditions was found.  Our results highlight the singularities of desert truffles with respect to other mycorrhizal fungi while providing a first glimpse on plant and fungal determinants involved in ecto to endo symbiotic switch that occurs in desert truffle under dry conditions.