Rory Osborne, Laura Rehneke, Silke Lehmann, Jemma Roberts, Melina Altmann, Stefan Altmann, Yingqi Zhang, Eva Köpff, Ana Dominguez-Ferreras, Emeka Okechukwu, Chrysi Sergaki, Charlotte Rich-Griffin, Vardis Ntoukakis, Ruth Eichmann, Weixing Shan, Pascal Falter-Braun & Patrick Schäfer

The mechanisms of symbiont-mediated beneficial effects and similarities and differences to pathogen strategies are mostly unknown. Here, we use 106 (effector-) proteins, secreted by the symbiont Serendipita indica (Si) to modulate host physiology, to map interactions with Arabidopsis thaliana host proteins. Using integrative network analysis, we show significant convergence on target-proteins shared with pathogens and exclusive targeting of Arabidopsis proteins in the phytohormone signalling network. Functional in planta screening and phenotyping of Si effectors and interacting proteins reveals previously unknown hormone functions of Arabidopsis proteins and direct beneficial activities mediated by effectors in Arabidopsis. Thus, symbionts and pathogens target a shared molecular microbe-host interface. At the same time Si effectors specifically target the plant hormone network and constitute a powerful resource for elucidating the signalling network function and boosting plant productivity.

Nature Communications. July 2023