Investigating the molecular interplay between plant immunity and the leaf microbiota

• Applicant: Professorin Dr. Julia Vorholt
• Subject Area: Microbial Ecology and Applied Microbiology ; Organismic Interactions, Chemical Ecology and Microbiomes of Plant Systems
• Term: since 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 402123997

Plants are colonized by a large and diverse range of microorganisms referred to as the plant microbiota. Among these, bacteria are the most abundant inhabitants, and they colonize plants in taxonomically structured community composition. These bacterial communities extend the host phenotype and play an important role in plant growth and health. Our prior work in the SPP2125 has shown that the plant innate immune system in general, and reactive oxygen species (ROS)-mediated immunity in particular, has a significant impact on the bacterial community structure in the phyllosphere and prevents dysbiosis. However, it is currently unclear whether the plant immune system directly affects the majority of strains or whether it primarily keeps keystone species in check that themselves contribute to community assembly. In this project, we will use a synthetic community approach consisting of the model plant Arabidopsis thaliana and a genome-sequenced leaf bacterial strain collection that comprises exemplars from the majority of species found on A. thaliana leaves in nature. We will use synthetic drop-out communities to understand how the plant's immune system shapes the composition of the bacterial community and the abundance of different strains. Specifically, we will test the hypothesis that ROS signaling is a central part of a genetic network and functions as a rheostat to dynamically control the microbiota structure. In addition, we will investigate the boundaries between the pathogenic and beneficial potential of the members of the microbiota and the consequences for the health status of the host, and seek to identify novel immunomodulating features. Overall, this project will contribute to our understanding of the plant immune system and its role in controlling the structure and function of the plant microbiota.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2125: Deconstruction and Reconstruction of the Plant Microbiota "DECRyPT"
• International Connection: Switzerland