Torriani*, Stefano F. F.; Goodwin⁺, Stephen B.; Kema^#, Gert H. J.;  Pangilinan^§, Jasmyn L.; McDonald, Bruce A. Intraspecific comparison of complete mitochondrial genome sequences from two strains of the plant pathogenic fungus Mycosphaerella graminicola. In: International Meeting on "Population and Evolutionary Biology of Fungal Symbionts", Ascona, Switzerland, 2007. AB-53.

Complete mitochondrial genomes of two isolates of Mycosphaerella graminicola were sequenced to confirm previous RFLP results showing very low levels of mitochondrial genetic variability of this plant-pathogenic ascomycete. The mitochondrial genome of M. graminicola is a circular molecule of approximately 43,960 bp containing the typical genes coding for 14 proteins related to oxidative phosphorylation, one RNA polymerase, two rRNA genes and a set of 27 tRNAs. The mitochondrial DNA of M. graminicola lacks the gene encoding the putative ribosomal protein (rsp3-like), commonly found in fungal mitochondrial genomes. Most of the tRNA genes were grouped, with the two larger clusters showing conservation of tRNA gene position with other ascomycetes. Intraspecific nucleotide variation was extremely low between the two sequenced strains of M. graminicola (IPO323 and STBB1) originating from Europe and North America, supporting previous findings of low mitochondrial diversity. The two sequences are the first from the Dothideomycetes and provide the basis for developing new tools to identify and exploit polymorphic regions in the mitochondrial genome to better understand the evolution of fungicide resistance and the conflicting pattern of high nuclear and low mitochondrial diversity present in M. graminicola populations around the world.

Keywords: comparative genomics, genome organization, microsatellites, mitochondrial genome, Septoria tritici

*Institution: ETH Swiss Federal Institute of Technology Zürich, Institute of Integrative Biology, Plant Pathology group / ⁺USDA-ARS, Purdue University, West Lafayette, IN, USA / ^#Plant Research International B.V., Wageningen, The Netherlands / ^§Department of Energy Joint Genome Institute, Walnut Creek, CA, USA

Email: stefano.torriani@agrl.ethz.ch