Phylogeny and Co-evolution of Fungal Mutualists (Ascomycota) of Arthropods

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The proposed study will build upon two data bases of DNA sequences ınuclear encoded small subunit ribosomal DNA (SSU rDNA) and B-subunit of vacuolar ATPase (vATPase)!. Cladistic analysis of sequences from taxa selected in a current study to reconstruct the phylogeny of ascomycetes with features enhancing arthropod dispersal supports the hypothesis that these features (including long-necked ascomata and evanescent asci) are examples of convergence and parallelism in fungi. The research proposed here includes 1) field studies to provide fungal life history details within the complex arthropod assemblages and to obtain specimens for 2) expansion of the molecular data sets. Taxon sampling is based upon the hypothesis that phoretic symbioses of fungi and arthropods provide opportunities for obligate mutualisms between the organism. Taxa for sequencing (yeasts, pleomorphic ascomycetes with yeast stages, and some apothecial forms) include many species that have mutualistic associations with arthropods. Due to the sampling design, an additional outcome of the study may be answers to age-old questions of fungal phylogeny. These questions include the relationships of yeasts to other fungi (reduced and non-monophyletic as currently suggested?) and the relative position of perithecial and apothecial ascomycetes to each other and to yeasts (also involving questions of monophyly). Established field and culture techniques as well as DNA sequencing will be used to obtain data. Cladistic analysis will be performed on the independent rDNA and vATPase data sets, and congruence (or non-congruence) will be used as a measure of support of the hypotheses.