P-068 - Proximity labelling for detection of effector-receptor interactions in the Nicotiana benthamiana apoplast

Wheat is a major cereal crop globally, contributing significantly to agricultural production. Zymoseptoria tritici causes Septoria tritici blotch (STB), a damaging disease in all wheat-producing regions. Given the limited genetic diversity among elite cultivars, identifying new and effective resistance sources is crucial. This study builds on the observation that several Z. tritici effectors are recognised in the non-host plant Nicotiana benthamiana but not in the natural wheat host. Our goal is to identify the recognition determinants for these Z. tritici effectors which could provide new sources of resistance.

Proximity labelling using TurboID has emerged as a powerful tool for studying proximal and low-affinity protein interactions. However, applying this approach in the apoplast presents challenges due to the unique extracellular environment. In a pilot study, we characterised the interaction between the oomycete apoplastic elicitor INF1 and the cell-surface receptor-like protein (RLP) REL to demonstrate the feasibility of proximity labelling in the apoplast. By supplying external ATP and magnesium acetate, we successfully detected biotinylation of plant proteins in the apoplast of N. benthamiana leaves. The next step involves confirming that REL interacts with INF1 through mass spectrometry analysis. Simultaneously, we are extending this approach to investigate the interactomes of the Z. tritici effectors Zt9, Zt11, and Zt12 to understand their recognition mechanisms.