Abstract - The ability to rapidly adapt to changing environments, especially to artificial environments created by industrial agriculture and modern medicine, is crucial for the success of pathogens infecting plants and animals. In some eukaryotic pathogens, rapid evolution can be mediated by genome rearrangements. Rearrangements and genetic variation are often associated with transposable elements and regions with distinct epigenetic signatures. Using the plant pathogenic fungus Zymoseptoria tritici as a model, we show that the genome of this fungus is highly unstable, especially under stress conditions. This instability is influenced by histone modifications that impact genome evolution by destabilizing (accessory) chromosomes and transcriptional regulation. We furthermore discovered intraspecies variation in DNA methylation, where loss of a DNA methyltransferase in populations outside of the center of origin reduced mutation rates in transposable elements. Taken together, variation of epigenetic regulation may represent an evolutionary trade-off offering adaptive potential at the cost of genome stability.

Biography - Dr Mareike Moeller (she/her) is currently a postdoctoral scientist at Oregon State University, USA, studying the influence of histone and DNA methylation on transcriptional silencing and genome stability in filamentous fungi. She did her BSc (Biology) and MSc (Molecular and Cellular Biology) at the University of Marburg and the Max Planck Institute for Terrestrial Microbiology in Germany. For her PhD, she moved to Kiel, Germany, where she worked on how epigenetic mechanisms contribute to genome evolution in fungal plant pathogens in the group of Prof Eva H. Stukenbrock at the University of Kiel and the Max Planck Institute for Evolutionary Biology. After completing her PhD, she received a postdoctoral fellowship from the German Research Foundation to join the group of Prof Michael Freitag at Oregon State University, USA.