Pamela Leonardi

Spatio-temporal dynamic of Tuber magnatum mycelium in natural truffle grounds.

Tuber magnatum produces the worlds most expensive truffle. This fungus produces very rare ectomycorrhizas which are difficult or even impossible to detect in the field. A “real-time” PCR assay was recently developed to quantify and to track T. magnatum mycelium in soil. Here, this technique was used to investigate the spatial distribution of T. magnatum extra-radical mycelium in soil productive patches and its dynamic across seasons. This study was carried out in four different natural T. magnatum truffle grounds located in different Italian regions. During the fruiting seasons, the amount of T. magnatum mycelium was significantly higher around the fruiting points and decreased going farther away from them. Moreover, T. magnatum mycelium inside the productive patches underwent seasonal fluctuations. In early spring, the amount of T. magnatum mycelium was significantly higher than in summer. In summer, probably due to the hot and dry season, T. magnatum mycelium significantly decreased, whereas in autumn it increased again and was concentrated at the putative fruiting points. These results give new insights on T. magnatum ecology and are useful to plan the most appropriate sampling strategy for evaluating the management of a truffle ground.

First evidence for truffle production from plants inoculated with mycelial pure cultures.

Truffle (Tuber spp.) cultivation is based on raising mycorrhizal trees in greenhouses that have been inoculated with suspensions of ascospores. The problem with this is that pests, pathogens, and other mycorrhizal fungi can contaminate the trees. Furthermore, because ascospores are produced sexually, each plant potentially has a different genetic mycorrhizal makeup from each other so tailoring the mycorrhizal component of plants to suit a particular set of soil and climatic conditions is out of the question. Here, we report on the production of Tuber borchii-mycorrhized plants using pure cultures, establishing a truffière with these and subsequent production of its fruiting bodies. This study opens up the possibility of producing commercial numbers of Tuber-mycorrhized trees for truffle cultivation using mycelial inoculation techniques. It also poses questions about the mechanism of fertilization between the different strains which were located in different parts of the experimental truffière.