Tuber magnatum (the white truffle) is the most precious species of the genus Tuber which comprises the hypogeous ectomycorrhizal species called “true truffle.” Despite its high economic value, the knowledge on its ecology is scant, principally due to the difficulty to find its mycorrhizas in the soil. The possibility to detect its mycelium by DNA extracted from soil has given a new chance for studying this truffle species. In this work, the co-occurrence of other Tuber species with T. magnatum mycelium was investigated by using species-specific primers in several productive areas located in central and northern Italy. Most (82%) of the examined soil samples showed at least one other Tuber species in addition to T. magnatum. The most common was T. maculatum (72% of soil samples) followed by T. borchii, T. rufum, T. brumale, T. dryophilum, T. macrosporum, and T. melanosporum (40%, 37%, 22%, 19%, 12%, and 1% of soil samples, respectively). Tuber aestivum was never detected in T. magnatum productive patches. Analysis of species co-occurrence showed that the pairwise associations between T. dryophilum-T. brumale, T. brumale-T. borchii, and T. borchii-T. dryophilum was significant. The results suggest that Tuber mycelial network in white truffle grounds is much more extensive than the distribution of their ectomycorrhizas and competitive exclusion between different Tuber species seems to take place only for root colonization.

块茎大块茎（白色块菌）是块茎类中最珍贵的物种，其中包括称为“真正的块菌”的皮毛外生菌根。尽管其具有很高的经济价值，但有关其生态学的知识很少，这主要是由于难以在土壤中发现其菌根。通过从土壤中提取DNA来检测其菌丝体的可能性，为研究这种松露菌种提供了新的机会。在这项工作中，通过使用位于意大利中部和北部几个生产性地区的物种特异性引物，研究了其他块茎物种与巨大隐孢子虫菌丝体的共存。大部分（82％）的土壤样本中除显示了至少一种其他块茎菌种麻疯树（T. magnatum）。最常见的是斑斑木耳（T. maculatum）（占土壤样品的72％），其次是博尔奇木（T. borchii），红褐麦草（T. rufum），布鲁马草（T. brumale），干枯草木（T. dryophilum），大孢子草（T. macrosporum）和黑麦草（T. melanosporum）（40％，37％，22％分别为19％，12％和1％的土壤样本）。从未在巨大的T. magnatum生产斑块中发现过小麦块茎。对物种共现的分析表明，T。dryophilum-T之间成对关联。布鲁马莱（T. brumale-T）。博尔奇（Borchii）和博尔奇（T. borchii-T。）干燥菌很显着。结果表明，块茎白松露地中的菌丝网络比其菌根的分布要广泛得多，不同块茎种之间的竞争排斥似乎仅发生在根部定植上。