Hoey, D. J. | bioRxiv Science

bioRxiv2024

An environment-responsive SCLA-type GRAS protein controls reproductive strategy in Marchantia polymorpha

By controlling their reproductive strategies, plants strike a balance between generating genetic diversity or maintaining stability, promoting long-term survival in a range of environmental conditions. The liverwort Marchantia polymorpha propagates clonally through vegetative gemmae or via sexually generated spores, but our understanding of the genetic pathways underpinning reproductive decision-making is limited. GRAS transcriptional regulators are highly conserved proteins across land plants, with diverse functionality in stress and development. Here, we discover a central role for the SCLA-type transcription regulator MpGRAS7 in both stress signalling and reproduction in Marchantia. MpGRAS7 is highly expressed in gemma cups and gametangiophores and is activated in response to Far Red (FR) light and abscisic acid (ABA) environmental cues. Genetic dissection further suggests MpGRAS7 is required to maintain gemma dormancy, gemma cup frequency, and FR-induced gametangiophore development. The sequence conservation and expression patterns of MpGRAS7 orthologs in flowering plants hints towards the broader function of SCLA-type GRAS proteins in stress-regulated developmental transitions in plants.

plant biology↗

bioRxiv2023

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.

plant biology↗