The Marchantia pangenome reveals ancient mechanisms of plant adaptation to the environment

Plant adaptation to a terrestrial life 450 million years ago played a major role in the evolution of life on Earth. This shift from an aquatic environment has been mostly studied by focusing on flowering plants. Here, we gathered a collection of 133 accessions of the non-vascular plants Marchantia polymorpha and studied its intraspecific diversity using selection signature analyses, genome-environment association study and a gene-centered pangenome. We identified adaptive features shared with flowering plants, such as peroxidases or nucleotide-binding and leucine-rich repeat (NLR), which likely played a role in the adaptation of the first land plants to the terrestrial habitat. The M. polymorpha pangenome also harbored lineage-specific accessory genes absent from seed plants. We conclude that different land plants lineages still share many elements from the genetic toolkit evolved by their most recent common ancestor to adapt to the terrestrial habitat, refined by lineage specific polymorphisms and gene family evolutions.