Reassessment of phylogenetic relationships of some lentinoid fungi with velutinate basidiomes based on partial 28S ribosomal RNA gene sequencing

Douanla-Meli C. & Langer E. (2010) Reassessment of phylogenetic relationships of some lentinoid fungi with velutinate basidiomes based on partial 28S ribosomal RNA gene sequencing.

Sydowia 62 (1): 23–35

Lentinoid fungi characterised by villosity of pileus and/or stem mostly belong to the genera Lentinus and Panus. However, morphology-based taxonomy of some of these species has remained controversial and they used to be classified back and forth between the two genera. The aim of this study was to investigate the phylogenetic relationships of these velutinate lentinoid fungi based on partial sequences of nuclear large subunit (nucLSU) rDNA. Fourteen sequences generated from Cameroon specimens out of which eleven sequences of velutinate collections were included in the dataset of taxa belonging to the polyporoid clade; their phylogeny was obtained by Bayesian, maximum parsimony, and likelihood analyses. In all trees a clade comprising all Lentinus taxa was resolved, whereas taxa referred to as Panus spp. formed a strongly supported monophyletic group. Species with velutinate to tomentose basidiomes were distributed over both clades. Those with pilose-strigose basidiomes and corresponding to Lentinus subsect. Criniti grouped together in the Lentinus clade. Contrarily, species with velutinate to strigose basidiomes and thick-walled skeletocystidia, which are considered belonging to Lentinus sect. Velutini, nested in the Panus clade, but were nonmonophyletic. In this latter clade, the P. velutinus complex, including taxa with velutinate to hispid-strigose basidiomes and long-slender stems, was moderately supported. The results indicated that the combination of uninflated vegetative hyphae, unbranched skeletal hyphae, and a radiate hymenophoral trama type is phylogenetically supported and characterises those species in the Panus clade.

Keywords: lamellate Polyporales, Lentinus, Panus, hyphal pegs, nucLSU phylogeny, ribosomal RNA