A MULTI-GENE MOLECULAR SYSTEMATIC STUDY OF THE KICKXELLOMYCOTINA, INCLUDING THE EXAMINATION OF TWO NEW GENES (MCM7 AND TSR1) FOR PHYLOGENETIC INFERENCE by

The protein-coding genes MCM7 and TSR1 have shown significant promise for phylogenetic resolution within the Ascomycota and Basidiomycota, but have remained unexamined within other fungal groups (except for Mucorales). We designed and tested primers to amplify these genes across early-diverging fungal clades, with emphasis on the Kickxellomycotina, zygomycetous fungi with characteristic flared septal walls forming pores with lenticular plugs. Phylogenetic tree resolution and congruence with MCM7 and TSR1 were compared against those inferred with nuclear small (SSU) and large subunit (LSU) rRNA genes. We also combined MCM7 and TSR1 data with the rDNA data to create 3and 4-gene trees of the Kickxellomycotina that help to resolve evolutionary relationships among and within the core clades of this subphylum. Phylogenies suggest that Orphella, Barbatospora, Spiromyces, and Ramicandelaber may represent unique lineages. These two new protein-coding genes may be more broadly useful for phylogenetic studies among other groups of early-diverging fungi.