Molecular phylogenetics of Ramaria and related genera: evidence from nuclear large subunit and mitochondrial small subunit rDNA sequences

Abstract

Phylogenetic relationships of the genus Ramaria and additional related taxa were examined through phylogenetic analysis of mitochondrial and nuclear ribosomal DNA sequence data. Related genera included Clathrus, Clavariadelphus, Gautieria, Gomphus, Hysterangium, Kavinia and Pseudocolus. Outgroup genera included Bondarzewia, Favolus, Ganoderma, Lactarius and Russula. The nuclear large subunit ribosomal DNA (nuc LSU rDNA) (approx. 610 bp) from 78 collections including 34 Ramaria species was used to test generic, subgeneric and selected species concepts for Ramaria. The mitochondrial small subunit ribosomal DNA (mt SSU rDNA) (ca 470 bp) from 51 representative holobasidiomycetes including ten Ramaria species also was used to independently test the monophyly of the genus Ramaria. Parsimony analyses of both datasets indicated that the genus Ramaria was paraphyletic and that several morphologically distinct groups of holobasidiomycetes were derived from ramarioid ancestors. In the nuc LSU rDNA analyses, Gautieria was nested among the terricolous Ramaria species and was closely related to R. subg Ramaria. The nuc LSU rDNA results also indicated that R. subg Laeticolora and R. subg Lentoramaria formed paraphyletic grades. Ramaria subg Laeticolora was paraphyletic due to the terminally derived R. subg Ramaria/Gautieria clade and a nested Gomphus. Ramaria subg Lentoramaria was paraphyletic due to a nested Clavariadelphus, Kavinia, and R. abietina of subg Echinoramaria. Both the nuc LSU rDNA and the mt SSU rDNA analyses demonstrated strong bootstrap support for the inclusion of the Phallales with the ingroup taxa, but the relationship of the Phallales to the Gomphales was indeterminate. Selected species concepts were also tested (e.g., R. amyloidea and R. celerivirescens, and R. araiospora and R. stuntzii). These data rejected the monophyly of Ramaria and suggested that the ramarioid morphology and lignicolous substrate affinity were ancestral for the Gomphales.