Optimized conditions for mycorrhiza formation between the pink rockrose (Cistus incanus) and the black Périgord truffle (Tuber melanosporum)

Abstract

Motivated by the increasing interest in the black Périgord truffle (Tuber melanosporum), we have been seeking to develop a controlled cultivation method for this celebrated fungus. Our strategy is based on establishing optimal conditions for mycorrhizal development in detached media by mimicking natural productive truffle beds. Cistus incanus, a Mediterranean shrub, was used as host. The components of the growth medium—polystyrene foam flakes, Perlite, peat, and dolomite powder—provided the coarse and fine porosity required for adequate drainage, appropriate balance between aeration and moisture, the desired pH (7.5-8.2), and support of mycorrhizal development. Optimum rhizosphere temperatures for inoculation and continued mycorrhizal development were 20-25 °C. Inoculation with mycorrhized root fragments proceeded more rapidly than traditional inoculation with a carpophore suspension, particularly at suboptimal growth medium temperatures. A keystone of our system is to determine the optimum root volume required for well-established plants, while using root restriction as an efficient means to maintain an advanced mycorrhizal development. The soilless culture of C. incanus and T. melanosporum can be useful for studying the course of carpophore induction and development.

Keywords:

• Cistus incanus
• ectomycorrhiza
• rhizosphere temperature
• soilless culture
• Tuber melanosporum