The proposed research concerns the phylogenetic relationships of cyphelloid and aquatic
homobasidiomycetes. Cyphelloid homobasidiomycetes include roughly 300 species that have minute
cup-shaped or tubular fruiting bodies. These fungi have been grouped in the family Cyphellaceae (or
Porotheleaceae), but it is widely accepted that they are polyphyletic. Aquatic homobasidiomycetes
include about 20 marine and freshwater species (including sexual and asexual taxa), some of which
have modified spores with elongate appendages that presumably function in dispersal in aquatic
habitats. A few aquatic homobasidiomycetes can be tentatively linked to certain terrestrial groups
based on morphology, but many are taxonomically enigmatic.

Recently, we discovered that the marine homobasidiomycete, Nia vibrissa (which has
appendaged spores and a puffball-like enclosed fruiting body), is closely related to the terrestrial
cyphelloid fungus, Henningsomyces candidus (Binder et al., 2001). The sister group of the Nia-
Henningsomyces clade includes Schizophyllum commune and Fistulina hepatica, which have unusual
gill-like and pore-like spore-bearing structures, respectively. Preliminary analyses combining
published sequences and unpublished sequences from our laboratory suggest that there may be many
other cyphelloid forms in these groups, as well as certain resupinate (crust-like) forms, poroid forms,
and at least two additional marine taxa. If this is correct, then the Nia-Henningsomyces clade plus the
Schizophyllum-Fistulina clade provide dramatic examples of morphological and ecological
diversification in homobasidiomycetes. However, preliminary analyses also suggest that many other
cyphelloid and aquatic fungi occur outside of these groups.

The central goal of the proposed research is to delimit the major clades of cyphelloid and
aquatic homobasidiomycetes and identify their closest relatives. Special emphasis will be placed on
taxa that may be related to the Nia-Henningsomyces clade and the Schizophyllum-Fistulina clade.
Much of the material required for this study is available in herbaria and culture collections, but we
will also undertake several collecting trips in the neotropics (Puerto Rico and Panama) and the
temperate zone (New England).

Phylogenetic analyses will occur in two phases. In the first phase, nuclear large subunit
ribosomal DNA (nuc-lsu rDNA) sequences will be obtained from all individuals studied. These data
will be added to reference datasets drawn from the emerging nuc-lsu rDNA database of
homobasidiomycetes, which derives largely from the work of Moncalvo and Vilgalys and Langer, as
well as our own work. Analyses of the nuc-lsu rDNA data will permit resolution of terminal clades of
cyphelloid and aquatic homobasidiomycetes, but this region probably will not provide robust resolution
of higher-level relationships of homobasidiomycetes. In the second phase of phylogenetic analyses,
exemplars of major groups of cyphelloid and aquatic homobasidiomycetes will be selected (based on
results of nuc-lsu rDNA analyses) for inclusion in a four-region dataset, which will contain nuclear and
mitochondrial large and small subunit rDNAs. Based on results of a recent study (Binder and Hibbett, in
review), the four-region dataset is expected to resolve deeper nodes in the homobasidiomycetes, which
will make it possible to place the major groups of cyphelloid and aquatic homobasidiomycetes in a
broad phylogenetic context. Ancestral state reconstruction (using both parsimony and maximum
likelihood approaches) will be performed to infer the historical pattern of transformations between
cyphelloid and other fruiting body forms, as well as transitions between aquatic and terrestrial
habitats.
 

Training and outreach are important aspects of the proposed research. This project will continue
the collaboration of DSH and MB, and will also support a Ph.D. student (Mr. Zheng Wang) and several
Clark University undergraduates (who we hope to support via REU supplements, as we have done in
the past). This project will also involve local high school students and high school biology teachers,
who will take part in six-week summer research experiences. The high school teachers will receive
professional development points, which are required for certification by the Massachusetts
Department of Education. Lastly, this project will provide funds to support a two-month research visit
by a German Ph.D. student, Ms Philomena Bodensteiner, who is studying taxonomy of cyphelloid fungi
under the direction of Prof. Dr. Reinhard Agerer (University of Munchen).

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