Leveraging genetic diversity in the model liverwort Marchantia to discover novel immunity mechanisms in plants. – LEVEL-UP

The diversity of plant immune mechanisms, shaped by 450 million years of evolution remains largely unexplored. The “LEVEL-UP” proposal will take advantage of a unique collection of 200 sequenced accessions of the model liverwort Marchantia polymorpha to run Genome Wide Association Study (GWAS) for the first time in a non-angiosperm plant and uncover novel immunity mechanisms. We will use complementary pathosystems with filamentous pathogens (oomycete and fungi) representing the diversity of pathogen lifestyles (e.g. biotrophy, hemibiotrophy and necrotrophy), either isolated from M. polymorpha or crops. In-depth cytological characterisations of each selected pathosystem coupled with phylotranscriptomic studies on different representatives of non-vascular and vascular land plants will reveal the universal components of plant immunity or those that are specific to each lineage tested. In parallel, and in a complementary manner, conserved factors or specific adaptations, which are involved in the virulence of broad host spectrum filamentous pathogens, will also be identified. Ultimately, this work will shed light on a still hidden part of the role of evolution on plant immunity. We will use genome editing to validate new resistance genes identified in M. polymorpha, paving the way for assessing their transferability from bryophytes to angiosperms.