P-108 - AI-guided identification of novel extracellular protein interactions between wheat and Zymoseptoria tritici

The apoplast is the frontline of plant defense, with numerous induced hydrolases that may disrupt pathogen progression. Many adapted plant pathogens use small secreted proteins (SSPs) to suppress the harmful hydrolases. These dynamic interactions are key determinants of disease outcomes yet remain largely underexplored in many pathosystems. To address this, we investigated wheat and its major fungal pathogen Zymoseptoria tritici (Zt), which resides in the apoplast for most of its infection cycle and manipulates the host through yet unknown interactions. Leveraging AlphaFold Multimer, we screened for hydrolase-SSP interactions among 103 detected wheat hydrolases and 104 Zt SSPs, identifying 459 high-confidence complexes (0.8ipTM+0.2pTM > 0.75) from 10,712 predicted models. Manual inspection suggested 69 inhibitory interactions, which we are validating through in vitro enzymatic assays and activity-based protein profiling. Additionally, we are clustering SSP structures from different Zt strains to study their evolution and understand their interaction dynamics. The study will generate an open-access database of predicted and confirmed wheat-Zt interactions, providing insights into disease mechanisms and informing durable crop protection strategies.