The -Barley Interaction Is a Versatile System for Characterization of Fungal Effectors.

Obligate biotrophic fungal pathogens, such as and , are amongst the most devastating plant pathogens, causing dramatic yield losses in many economically important crops worldwide. However, a lack of reliable tools for the efficient genetic transformation has hampered studies into the molecular basis of their virulence or pathogenicity. In this study, we present the -barley pathosystem as a model to characterize effectors from different plant pathogenic fungi. We generate solopathogenic strains, which form infectious filaments without the presence of a compatible mating partner. Solopathogenic strains are suitable for heterologous expression system for fungal virulence factors. A highly efficient Crispr/Cas9 gene editing system is made available for . In addition, infection structures during barley colonization are analyzed using transmission electron microscopy, showing that forms intracellular infection structures sharing high similarity to haustoria formed by obligate rust and powdery mildew fungi. Thus, has high potential as a fungal expression platform for functional studies of heterologous effector proteins in barley.