Dissertation Research: Molecular Phylogenetics of Phlebia (Basidiomycotina) and Related Genera

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The taxonomic study of fungi is difficult because of the simple morphology and plasticity of these organisms. One method that shows great promise in resolving questions in fungal taxonomy is DNA analysis. In fungi there are two kinds of DNA: (1) DNA that occurs in the mitochondria (mtDNA) and encodes genes necessary for mitochondrial (energy) functions; and (2) DNA in the nucleus encoding all other genes. Because mtDNA is easy to extract and characterize, it has been favored in taxonomic studies of fungi. Mapping of restriction sites and sequencing of conserved genes are the best approaches to study mtDNA in fungi. Graduate student Karen Nakasone, under the direction of faculty adviser Dr. Ken Sytsma, will obtain both kinds of data. The data will be analyzed in two basic ways: (1) to calculate overall genetic similarity between samples and (2) to determine phylogenetic relationships between taxa. The genus Phlebia consists of small and inconspicuous but ubiquitous fungi that decay wood. Some species show great potential in the biomechanical pulping of wood. The objectives of this study are: (1) to delimit and define the 30-35 species of Phlebia that occur in North America based on morphology, laboratory cultures, and DNA characteristics and to assess the reliability of traditional morphological characters in their taxonomy; (2) to determine the phylogenetic relationships of species within Phlebia and of Phlebia to other genera in the family; and (3) to study the inheritance of mtDNA in Phlebia and relate these findings to other fungi. The study will contribute to establishing a reliable taxonomy of these fungi, one that reflects evolutionary relationships.