Molecular phylogeny of ectomycorrhizal fungi in the family Boletaceae from North and Northeastern of Thailand

Abstract

The ectomycorrhizal basidiocarps in the family Boletaceae were collected from various forests and plantations in five provinces, Chiang Mai, Chaiyaphum, Nan, Phitsanulok and Ubon Ratchathani. Ninety-five basidiocarps were classified in 8 genera, Boletus (24 species), Tylopilus (14 species), Boletellus (5 species), Strobilomyces (4 species), Heimioporus (3 species), Lecinum (2 species), Pulveroboletus (1 species) and Zangia (1 species). Phylogenetic relationships among ectomycorrhizal Boletaceae were studied based on both ribosomal DNA regions, internal transcribed spacer (ITS) and large subunit (LSU). ITS and LSU sequences of Thai specimens were compared with some species in Boletaceae available in GenBank database. Phylogenetic analysis based on ITS suggested that Boletellus, Heimioporus, Pulveroboletus and Strobilomyces were monophyletic groups while Boletus and Tylopilus were not monophyletic groups. It was dissimilar to phylogenetic tree based on LSU which indicated that only Heimioporus, Pulveroboletus and Strobilomyces were monophyletic groups. This inconsistence might be from the few ITS sequences in each genus. However, the relationships among genera were still unclear. In addition, the phylogeny of the large genus, Tylopilus was investigated based on both rDNA regions. Two similar phylogenetic analyses showed that Tylopilus could be clearly divided into at least 4 clades. Moreover, the relationships among Tylopilus species corresponded to their host plant families. Fourteen Tylopilus species existed in Thailand. Moreover, this study provided the important morphological and molecular database of tropical Boletaceae. Nevertheless, more information both morphology and molecular studies in this family especially in tropical region is significantly needed to fulfill the systematic study of Boletaceae.