An approximation to the phylogeny of Sclerotinia and related genera

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Abstract
Phylogenies are constructed based on nuclear ribosomal internal transcribed spacer (ITS) DNA sequences from an ingroup consisting of 50 isolates representing 24 species of the discomycete family Sclerotiniaceae and an outgroup consisting of five related taxa of the same family. The ingroup taxa are: three Botrytis spp., two Botryotinia spp., one Ciborinia sp., one Dumontinia sp., one Grovesinia sp., six Myriosclerotinia spp., nine Sclerotinia spp. and one Sclerotium sp. The outgroup taxa are: one Ciboria sp., one Encoelia sp. and three Monilinia spp. The type species is included for all taxa except for Ciborinia and Encoelia. Several of the included taxa are important plant pathogens. The resulting phytogenies are discussed with regard to morphology, life history and taxonomy. A suspected relationship between Sclerotinia borealis and S. tetraspora, and Myriosclerotinia is rejected, while a suspected relationship between Ciborinia ciborium and Myriosclerotinia is strongly supported. Sclerotinia ulmariae, previously synonymized with Dumontinia tuberosa, is reinstated as an independent species of Dumontinia. Two new combinations, Dumontinia ulmariae and Myriosclerotinia ciborium, are proposed. The imperfectly known taxon Sclerotium cepivorum seems most closely related to Dumontinia. We conclude that Dumontinia, and Myriosclerotinia, as currently conceived, are monophyletic, and that Botryotinia along with Botrytis anamorphs probably also constitute a monophyletic lineage. The genus Sclerotinia is probably polyphyletic and characterized by symplesiomorphies rather than synapomorphies. Two putatively new taxa, Sclerotinia sp. 1, and Sclerotinia sp.2 are most closely related to S. minor, S. sclerotiorum and S. trifoliorum, and to S. borealis, respectively.