Ruben obtained his Bachelor's degree at the University of Münster in 2019 and his Master's degree at the University of Düsseldorf and Cologne in 2022 in the frame of the CEPLAS Graduate School. In his PhD project he focuses on the molecular mechanisms underlying plant-protective fungus-fungus interactions.

The root endophytic fungus Serendipita indica displays several beneficial effects on plants, including growth promotion and nutrient supply. Moreover, S. indica can protect barley and Arabidopsis from the necrotrophic pathogen Bipolaris sorokiniana. This protection is thought to strongly rely on a direct antagonism between the mutualistic and the pathogenic fungus. However, the precise molecular mechanisms of this antagonism are not yet known. Transcriptomics revealed that during fungus-fungus interaction, a set of effector proteins, including small-secreted proteins (SSPs), proteases, and CAZymes is induced in S. indica.  Using protein purification, genetic manipulation, and physiological methods, he investigates the antifungal effects of these S. indica effectors towards B. sorokiniana and the underlying mechanism of action. One of these effectors is a secreted GH18-CBM5 chitinase that decreases the fungal viability, plant colonization success, and disease symptoms of B. sorokiniana. In the long run, he wants to understand how different fungal effectors act synergistically to inhibit fungal plant pathogens.