P-089 - The immune system of ferns and liverworts

The diversity of land plants includes angiosperms, bryophytes and ferns, which may deploy specific strategies to resist against pathogens. We propose to investigate this question in bryophytes, using Marchantia polymorpha and in ferns, using Pteris vittata.

In bryophytes, we investigated natural variation of a M. polymorpha population in response to the Fabaceae-infecting oomycete Aphanomyces euteiches. GWAS revealed genes associated with resistance, including genes encoding putative immune receptors and transcription factors. We also measured gene expression changes mediated by A. euteiches in M. polymorpha. We found that some genes identified by GWAS are as well deregulated by A. euteiches. The characterization of some gene candidates is ongoing.

In ferns, we established novel pathosystems and investigated the diversity of two immune receptors families: receptor-like kinase and proteins (RLKs/RLPs) and nucleotide-binding and leucine-rich repeats (NLRs). Ferns likely counter some microbe with nonhost resistance and some with specific defence mechanism. Ferns have many RLKs and RLPs, reminiscent to those required for cell-surface immunity in angiosperms. They also produce NLRs, including a class absent in angiosperms, with a disordered N-terminal domain, that we called disN-NLR. Our findings on pathosystems in ferns and their immune receptors open exciting perspectives for future research on disease resistance evolution and crop protection strategies.