Cell biology of corn smut disease - Ustilago maydis as a model for biotrophic interactions

Ustilago maydis is a well-established model system for biotrophic fungal plant pathogens. The fungus has a dimorphic life cycle with a yeast-like saprophytic phase switching to filamentous, pathogenic growth upon hyphal fusion. Due to its highly differentiated development and the amenability for reverse-genetics U. maydis provides a model system for both fungal cell biology as well as the study of biotrophic plant interaction. The present article highlights key findings in different aspects of cell biology on the corn smut disease and provides an outlook on the most intriguing open questions.