Magnaporthe oryzae effectors utilized by the fungal plant pathogen to manipulate host resistance responses at different stages of the hemi-biotrophic infection process

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Food securing for an ever growing word population is one of the main global challenges in our century. Generally, crop yield is not only threatened by climate change or natural catastrophes but also by plant pathogens which have the capacity to completely destroy the harvest. Treatments with chemicals to control diseases are expensive and thus not applicable throughout the world and in addition might impact the environment in an unforeseeable fashion. Therefore an ideal way to guarantee reliable harvests would be to provide plants with a genetic constitution to naturally withstand pathogen attack. To generate such smart plants an in-depth knowledge of the molecular requirements of pathogens to cause disease is essential.The proposed project will address this important issue by analyzing the fungal plant pathogen Magnaporthe oryzae. This pathogen is capable to destroy each year rice harvests that otherwise could have feed 60-million people and was ranked as the no. 1 plant pathogen for its scientific/economic importance (Dean et al., 2012). The life-cycle of M. oryzae is rather complicated encompassing different stages in which the fungus initially feed from living host tissue but later-on produces toxins leading to host cell death. This infection strategy is referred to a hemi-biotrophy. Despite roughly 20 years of research, the infection process of the microbe on its host plant is not fully understood at the molecular level. We aimed at closing this gap in an integrated approach encompassing the analyses of all infection stages of the pathogen. This ambitious project will be realized based on the long-standing expertise of the two proposing research labs from Germany and China who will join their forces to fight against a global threat.What is becoming increasingly apparent is the involvement of small molecules, so-called effectors, secreted by pathogens which sabotage the host defense machinery, in making plants accessible for colonization by the pathogen. This is mediated by interaction of the effectors with host proteins necessary for mounting resistance responses. The Schaffrath- and the Zhang-labs both have successfully worked on the discovery and characterization of M. oryzae effectors. So far both have concentrated mostly on particular stages of pathogen development, thereby being able to provide only a snap-shot of the whole effector picture. Aiming at providing the global view, the actual proposal addresses the effectome across all stage of colonization, i.e. penetration, biotrophic and necrotrophic development. This will pave the way to a knowledge-based generation of smart plants.