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Toward a Global
Phylogeny of the Boletales
The
Boletales is a monophyletic order of homobasidiomycetes (Fungi) that
includes approximately 1025 described species that are distributed
worldwide. The Boletales are diverse in both morphology and ecology.
Fruiting bodies in the group include stipitate-pileate forms (those with a
stalk and cap), crust-like resupinate forms, earthballs, and false truffles.
Members of the Boletales obtain carbon nutrition by entering into
ectomycorrhizal symbioses or by decaying wood, and a few are suspected to be
mycoparasites. Some are highly prized edibles; others are important food
sources for mammals, and many are rearing sites for insects.
The
Boletales have been widely studied by fungal systematists, chemists,
ecologists, and mycorrhizal biologists. However, investigations in all these
areas have been hampered by the lack of a comprehensive phylogenetic
classification for the group. For example, poor resolution of the basal
clades of Boletales makes it difficult to infer the ancestral form of the
group; lack of understanding of generic boundaries makes it difficult to
assess relationships of newly discovered species; and ambiguous species
limits within many clades are a barrier to ecology and biodiversity studies.
We propose to perform an
intensive molecular phylogenetic study across all major groups of the
Boletales. The proposed research involves two nested subprojects:
1.
A multi-gene analysis using exemplars of all major groups of
Boletales and representatives of potential outgroups in the
homobasidiomycetes. We will analyze a dataset of six loci (nuc-ssu, nuc-lsu,
atp6, RPB1, RPB2, EF-1a)
of 52 species from the major clades of Boletales, as well as potential
outgroup taxa. The goals of these studies are to provide a “backbone”
phylogeny and resolve the major clades of Boletales.
2.
A survey of diverse Boletales, using nuclear large-subunit rDNA and ITS
sequences. We will analyze an extensive data set of nuc-lsu rDNA and ITS
sequences of approximately 700 species from all continents except
Antarctica, with an emphasis on North American, European, and neotropical
material. The goals of these studies
are to
develop a broad phylogenetic framework for the Boletales; provide resources
for species-level taxonomy and molecular ecology; and understand the
evolution of nutritional modes, fruiting body forms, and other characters.
Outreach activities
in this project will take two forms:
1.
We will create a series of pages in the Tree of Life Web Project for each of
the major groups of Boletales. These pages will bring information about the
diversity and ecology of Boletales to a broad audience, including students
and educators.
2.
We will design and implement a four-week learning module on "Molecular
Ecology and Systematics of Mycorrhizal Fungi" for high school students, in
collaboration with Minuteman Regional High School (Lexington, MA). This
module will engage students in a discovery-based research project that
demonstrates the integration of molecular biology, organismal biology, and
bioinformatics.
Significance:
Intellectual merit of
the proposed activity:
This project will
contribute to a phylogenetic classification of a large, ecologically
important clade of fungi. Well-sampled phylogenetic trees will permit
analyses of the evolution of fruiting body forms and other taxonomically
important characters, as well as transitions between symbiotic and
free-living lifestyles.
Broader impacts
resulting from the proposed activity:
This project will provide resources for
fungal molecular ecologists (specifically ITS sequences in GenBank) and
systematists, and will promote the discovery of new species of Boletales.
There are currently several ongoing projects in Boletales, but these are
either regional in scope, or limited to specific genera. The proposed
research will provide a comparative database that can be used to integrate
the results of disparate studies in Boletales and contribute to a global
classification of the group. The Tree of Life web pages will provide
resources for students and educators. The four-week module in “molecular
ecology and systematics of ectomycorrhizal basidiomycetes” for high school
students will raise awareness about fungal biology specifically, and
molecular approaches to problems in ecology and evolutionary biology. It
will also forge ties between a private liberal arts university (Clark
University) and a public high school (Minuteman Regional High School).
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