FELD 1/2025

Truffle The trees on the

Truffle The trees on the LIL truffle plantation are still too young to have truffles on their roots. Therefore, the lateral roots of some of the young trees are carefully exposed and samples are taken. These are examined under a microscope in the laboratory, and genetic analysis provides information about the type of mycorrhiza found. The tree produces sugar, which it then makes available to the truffle fungus. In return, the tree receives nitrogen and phosphorus, since the truffle fungus has better access to water than the tree roots. The fungus is aided in this by its fine hyphal network: underground thread-like cells that can absorb nutrients and water. If the proportion of truffle mushroom mycorrhiza is high, it is also very likely that the underground truffles will be able to grow. The lateral roots of some of the young trees are carefully exposed, and the samples later examined under a microscope in the laboratory. In addition, a genetic analysis is carried out to determine exactly which mycorrhiza is growing in each case. This will help to conclude as to whether the truffle fungus will be able to establish itself in the future or whether it will possibly be displaced by other fungi. Since, according to current findings, the mycorrhization rate needs to be significantly increased, so-called truffle traps are now to be used on a further 140 trees. This involves carefully introducing a substrate enriched with truffle spores into the root system. And then it’s time to wait and see. Search dog Erik found a few truffles after all. To train him, truffle expert and LIL project partner Tine Grebenc buried a few truffles he had brought along specifically for this purpose, and the well-trained dog found them all. The famous truffle pigs are now only used in a few regions of France, and then 32

Truffle It usually takes about ten years for truffles to form at the roots of trees. KATJA KÜHDORF mostly for show. Pigs are much more difficult to control when searching for truffles and often dig up the ground so much that no more truffles can grow. In addition, pigs love to eat truffles themselves; this is not a risk with dogs, such as Erik. So when truffles can hopefully be harvested in the Lusatia, our four-legged friend will leave enough for us humans. Text: Elke Thiele Dr. Katja Kühdorf conducts research at ZALF in the Microbial Biogeochemistry working group, focusing primarily on plant-fungus interactions (ectomycorrhiza). Dr. Tine Grebenc, from the Slovenian Forestry Institute, focuses his research on the diversity of hypogeous fungi (truffles) at the regional and global level. 33