Summary: With non-seed plant research gaining momentum and a vibrant community emerging, this Meeting Review highlights the growing impact of diverse model systems on key questions in plant evolution.

Receptor signalling determines cellular responses and is crucial for defining specific biological outcomes. In legume root cells, highly similar and structurally conserved chitin and Nod factor receptor kinases activate immune or symbiotic pathways, respectively, when chitinous ligands are perceived1. Here we show that specific amino acid residues in the intracellular part of the Nod factor receptor NFR1 control signalling specificity and enable the distinction of immune and symbiotic responses. Functional investigation of CERK6, NFR1 and receptor variants thereof revealed a conserved motif that we term Symbiosis Determinant 1 in the juxtamembrane region of the kinase domain, which is key for symbiotic signalling. We show that two residues in Symbiosis Determinant 1 are indispensable hallmarks of NFR1-type receptors and are sufficient to convert Lotus CERK6 and barley RLK4 kinase outputs to enable symbiotic signalling in Lotus japonicus.

Symbioses have been fundamental to colonization of terrestrial ecosystems by plants and their evolution. Emergence of the ancient arbuscular mycorrhizal symbiosis was followed by the diversification o...

Abstract. Plastids and mitochondria are key to plant survival and adaptation. The evolutionary progress of land plants (embryophytes) witnessed gene and ge

Abstract. The paradox of evolutionary stasis and dynamism—how morphologically static lineages persist through deep geological periods despite environmental

Defense-associated reverse transcriptases (DRTs) employ diverse and distinctive mechanisms of cDNA synthesis to protect bacteria against viral infection. However, much of DRT family diversity remains ...

Land plants include angiosperms, gymnosperms, bryophytes, lycophytes, and ferns, each of which may deploy distinct strategies to resist pathogens. Here, we investigate fern-pathogen interactions by characterizing novel pathosystems and analyzing the diversity of fern immune receptors. A collection of fern species was inoculated with a diverse set of filamentous microbes, and disease symptoms were assessed. We further leveraged published genome mining tools to analyse the diversity of receptor-like kinases, receptor-like proteins (RLKs/RLPs) and nucleotide-binding and leucine-rich repeats (NLRs), along with key immune signalling components, in ferns. Our results reveal that ferns exhibit a range of responses to pathogens, including putative non-host resistance and more specific resistance mechanisms. Among ten ferns tested, Pteris vittata displays the broadest spectrum of pathogen compatibility. Genome mining indicates that ferns encode a diverse repertoire of putative immune receptors, antimicrobial peptides, and mediators of systemic acquired resistance. Ferns possess numerous RLKs/RLPs, resembling those required for cell-surface immunity in angiosperms. They also encode diverse NLRs, including sub-families lost in flowering plants. These findings provide insights into disease resistance evolution and open promising perspectives for crop protection strategies.

The fossil record demonstrates that filamentous microbes invaded ancient plant cells with intracellular hyphal structures over 450 million years ago. To this day, a rich diversity of extant land plant...