Welcome to the Research Group 5682 MadFungi
Over the last 20 years, extensive knowledge has been acquired on the molecular mechanisms underpinning interactions between plant hosts and beneficial or pathogenic fungi. In contrast to the mechanisms responsible for virulence on the host, the principles underlying the fungal adaptation to specific niches in their host plant are poorly understood. We here define niche as the particular plant compartment that is occupied by the fungus and which is characterized by its microbial community and biophysical and biochemical properties. Adaptation to the host niche can be viewed as a gain of colonization efficiency of specific plant organs or cell types, which can involve the manipulation of plant metabolism and/or plant development to create unique compartments for fungal propagation. Adaptation is determined by various selection factors on the plant-colonizing fungi, as well as an interaction between the invading fungus and the plant microbiota during niche occupation. Both aspects have been insufficiently studied so far. However, recent findings indicate that fungi compete for the colonized space on the host plant against other microbes. Such microbial antagonisms can result, for example, from the secretion of antimicrobial effectors by pathogens. On the other hand, perturbations of host immunity and host nutrient availability by hostadapted fungi are plausible mechanisms to exclude or limit competing microbes from colonizing a particular host niche. In this Research Unit (RU), MadFungi, we aim to investigate the mechanisms of niche establishment employed by plant-colonizing fungi, focusing on inter-microbial competition. To this end, we will concentrate all our efforts on a single plant species, the crop barley, in combination with a range of fungi that exert different lifestyles, ranging from mutualistic to parasitic and from biotrophic to necrotrophic, and that have adapted to thrive in different niches of the barley plant (root, shoot, flowers; epiphytic, endophytic, apoplastic, intercellular). The RU consists of a team of leading experts with in-depth knowledge of molecular interactions between plants and fungi and one leading scientist in barley genetics and biotechnology. With this consortium, we aim to gain ground-breaking insights into the mechanisms of niche adaptation and defense against competing microbes and make new crosssystem comparisons by combining our expertise on the different fungal species and the barley plant.