Most land plants form a symbiosis with arbuscular mycorrhizal fungi (AM) to acquire water and phosphorus, while nitrogen-fixing symbiosis with rhizobia (NFS) is restricted to legumes (Oldroyd, 2013). Genetic studies have revealed the crucial roles of plasma membrane LysM Receptor-Like Kinases (LysM-RLK) in perceiving bacterial NOD-factors essential for establishing NFS (Buendia et al., 2018). In contrast, single loss-of-function mutants of LysM-RLKs in angiosperms only have quantitative effects on AM establishment, raising the question of whether AM formation strictly requires perception by LysM-RLKs of Myc-factors. To avoid potential functional redundancy in angiosperms, we conducted a systematic study using Marchantia paleacea, an AM forming liverwort which has only four LysM-RLKs in its genome. We generated all single loss-of-function mutants and examined their ability to host AM. In parallel, we generated similar mutants in a background expressing aequorin to assess their ability to respond to microbial compounds such as chitin oligomers (CO) and/or lipochitooligosaccharidic (LCOs) signals. Mutants of the CERK1 orthologue (MpaLYKa) completely lost the ability to establish AM while mutants of the single Marchantia LYR gene retained their ability to form AM. Interestingly, both MpaLYKa and MpalLYR mutants lost responsiveness to COs and MycLCOs as measured by cytosolic calcium variations. Furthermore, binding experiments demonstrated that MpalLYR is a bona fide receptor for this class of molecules. Overall, our findings question the crucial role of Myc-factors in AM establishment in Marchantia Paleacea.