Tricholosporum goniospermum, genetic diversity and phylogenetic relationship with the Tricholomatineae [formerly tricholomatoid clade]

The species Tricholosporum goniospermum is mainly known from north Europe and north Italy. However, recently, the presence of this species was reported also in central Italy. In this study we examined samples collected in central Italy that showed a spore size smaller than typically reported for this species. In agreement with morphological observations we found genetic polymorphisms in the ITS region suggesting that populations from central Italy are genetically different from those of northern Italy. Moreover, we detected intra-individual polymorphism in the ITS region. These fiding may be explained with the extremely fragmented habitat of this species that may represent a limit for gene flw. Based on morphology the genus Tricholosporum is currently classifid in the Tricholomataceae, however the presence of cruciate basidiospores represents a distinctive character with respect to other Tricholomataceae. Thus, we used nuclear ITS, LSU, SSU and rpb2 DNA sequences to evaluate the phylogenetic position of this genus within the clade of "tricholomatoid" fungi. This analysis showed a low affiity of Tricholosporum with the clade of the Tricholomataceae and an isolated position of this genus within the Tricholomatineae. Thus the analyses performed in this study provided further insight for the revision of the species and family in the Tricholomatineae.