Multilocus phylogenetic and coalescent analyses identify two cryptic species in the Italian bianchetto truffle, Tuber borchii Vittad.

Tuber borchii (Ascomycota, Pezizales) is a highly valued truffle sold in local markets in Italy. Despite its economic importance, knowledge on its distribution and genetic structure is scarce. The objective of this work was to investigate the factors shaping the genetic structure of T. borchii using 61 representative specimens with a broad distribution throughout Italy. In spite of the lack of morphological differences, phylogenetic and coalescent-based analyses using four loci identified two genetically isolated groups sympatrically distributed. The low levels of divergence between the two clades may be the result of recent range expansions from geographically distinct refugia, potentially mediated by reforestation using coniferous species that are common ectomycorrhizal symbionts for both groups.