Mycelium of Terfezia claveryi as inoculum source to produce desert truffle mycorrhizal plants.

Terfezia claveryi Chatin was the first desert truffle species to be cultivated, the mycorrhizal plants being successfully produced by using both desert truffle spores and mycelia. However, it is more advisable to use mycelium than spores whenever possible and profitable. Given the low yields of mycelia obtained using traditional culture methods of this truffle, the medium composition was modified in an attempt to determine its nutritional requirements. For this, an assay involving response surface methodology was performed using Box-Behnken design to find the optimal parameters for the high production of mycelial biomass. The best results were obtained with glucose as carbon source, buffering the pH at 5 during culture, adding a pool of vitamins, and adjusting the optimal concentrations of carbon and nitrogen sources of the MMN medium. Biomass production increased from 0.3 to 3 g L dry weight and productivity increased from 10.7 to 95.8 mg L day dry weight. The produced mycelium was able to colonize Helianthemum roots efficiently, providing more than 50% ectomycorrhizal colonization.