Taxonomic status of genera in the "Nowakowskiella" clade (Kingdom Fungi, Phylum Chytridiomycota)
Mozley, Sharon Elizabeth
MetadataShow full item record
Chytrid fungi represent the earliest group of fungi to have emerged within the Kingdom Fungi. Unfortunately despite the importance of chytrids to understanding fungal evolution, the systematics of the group is in disarray and in desperate need of revision. Funding by the NSF PEET program has provided an opportunity to revise the systematics of chytrid fungi with an initial focus on four specific clades in the order Chytridiales. The “Nowakowskiella” clade was chosen as a test group for comparing molecular methods of phylogenetic reconstruction with the more traditional morphological and developmental character system used for classification in determining generic limits for chytrid genera. Portions of the 18S and 28S nrDNA genes were sequenced for isolates identified to genus level based on morphology to seven genera in the “Nowakowskiella” clade: Allochytridium, Catenochytridium, Cladochytrium, Endochytrium, Nephrochytrium, Nowakowskiella, and Septochytrium. Bayesian, parsimony, and maximum likelihood methods of phylogenetic inference were used to produce trees based on one (18S or 28S alone) and two-gene datasets in order to see if there would be a difference depending on which optimality criterion was used and the number of genes included. In addition to the molecular analysis, taxonomic summaries of all seven genera covering all validly published species with a listing of synonyms and questionable species is provided to give a better idea of what has been described and the morphological and developmental characters used to circumscribe each genus. All of the isolates sequenced for the molecular portion of this study have been cryopreserved for future work and a review of cryopreservation of chytrid fungi is included. A modification of a previously published Q-tip method used to cryopreserve fungi for this study is also given.