A plant Lysin Motif Receptor-Like Kinase plays an ancestral function in mycorrhiza
Eve Teyssier, Sabine Grat, David Landry, Mathilde Ouradou, Mélanie K. Rich, Sébastien Fort, Jean Keller, Benoît Lefebvre, Pierre‐Marc Delaux, Malick Mbengué
Abstract
Arbuscular mycorrhiza (AM) with soilborne Glomeromycota fungi was pivotal in the conquest of land by plants almost half a billion years ago. In flowering plants, it is hypothesized that AM is initiated by the perception of AM fungi-derived chito- and lipochito-oligosaccharides (COs/LCOs) in the host via Lysin Motif Receptor-Like Kinases (LysM-RLKs). However, it remains uncertain whether plant perception of these molecules is a prerequisite for AM establishment and for its origin. Here, we made use of the reduced LysM-RLK complement present in the liverwort Marchantia paleacea to assess the conservation of the role played by this class of receptors during AM and in CO/LCO perception. Our reverse genetic approach demonstrates the critical function of a single LysM-RLK, MpaLYKa, in AM formation, thereby supporting an ancestral function for this receptor in symbiosis. Binding studies, cytosolic calcium variation recordings and genome-wide transcriptomics indicate that another LysM-RLK of M. paleacea , MpaLYR, is also required for triggering a response to COs and tested LCOs, despite being dispensable for AM formation. Collectively, our results demonstrate that the perception of symbionts by LysM-RLK is an ancestral feature in land plants, and suggest the existence of yet-uncharacterized AM fungi signals.