Phylogenetic relationships of cantharelloid and clavarioid Homobasidiomycetes based on mitochondrial and nuclear rDNA sequences

Abstract

Sequence data from mitochondrial and nuclear small subunit rDNA were used to estimate phylogenetic relationships of cantharelloid and clavarioid Homobasidiomycetes. Sixty-five diverse Homobasidiomycete species were investigated, including 23 cantharelloid and clavarioid species. Although nodes deep in the tree could not be resolved, four lineages containing cantharelloid and clavarioid fungi were identified, (i) Cantharellaceae (Cantharellus, Craterellus) is closely related to Hydnum, which is toothed, Stichoclavaria, which is a simple club, and Clavulina, which is coralloid. These taxa all have stichic nuclear division, which is a synapomorphy supporting this clade. (ii) Clavariadelphus is closely related to Gomphus and Ramaria. This relationship is supported by green reactions of sporocarps treated with iron salts, which is reflective of the presence of the compound pistillarin. The nearest relatives of these cantharelloid and clavarioid fungi are gastero-mycetes, including the earth star Geastrum, the stinkhorn Pseudocolus, and the “cannon-ball fungus” Sphaerobolus. (iii) The clavarioid fungi Clavaria, Clavulinopsis, Pterula, and Typhula appear to be derived from the lineage that contains most of the gilled fungi. (iv) Clavicorona is closely related to Auriscalpium, which is toothed, and Lentinellus, which is gilled. This lineage is united by amyloid spore ornamentation. Although these results suggest that there has been extensive convergence in fruiting body morphology, certain anatomical and biochemical features appear to be phylogenetically informative, notably stichic nuclear division, presence of pistillarin, and cyanophily or amyloidity of spore ornamentation.