Jeudi 11 janvier 2018 Amphi 2 (Bât 2Bis) à 14h00

Plant interactome network mapping to understand plant signaling and host-microbe interactions

Pascal Falter-Braun

(Institute of Network Biology (INET), Helmholtz Zentrum München & Ludwig-Maximilians-University, München, DE)

Biotic and abiotic stresses affect plant growth and threaten the capacity to feed a growing world population. To understand and alter how plants tolerate stress it will be critical to understand how the complex and dynamic molecular networks translate genome encoded and environmental information into phenotypes. INET maps and functionally studies plant protein-interaction and signaling networks in the context of biotic and abiotic stress responses using an interdisciplinary systems biology approach.

Plant pathogens sustain their infection by injecting virulence effectors into their host cytosol to manipulate its physiology and immune system. We performed a systematic high- throughput analysis of the physical protein-protein interactions of virulence effectors from a fungal, an oomycete and a bacterial pathogen with the protein network of their host Arabidopsis thaliana. The network was extensively validated using cell biological and genetic data. We showed that effectors from any individual pathogen and effectors from the three distant pathogens converge on common host targets. Integration of the plant- pathogen interactome network 2 with our previously obtained host network Arabidopsis Interactome 1 (AI-1) and with information on natural genetic variation reveals that direct interaction partners of the most intensely targeted host proteins and show clear signs of positive and balancing selection, suggesting that evolutionary adaptation occurs in the network neighborhood of the most targeted proteins. Mechanistically we showed that LSU1 stimulates chloroplastic H2O2 production in abiotic and biotic stress conditions. These finding reinforce the importance of analyzing infections and evolutionary processes from a network perspective. Future studies will be aimed at understanding how non-pathogenic microbes modulate their host metabolic and signaling networks.