Diversity, phylogeny, and adaptation of bryophytes: insights from genomic and transcriptomic data

We review recent advances in the knowledge of bryophyte diversity, phylogeny, and adaptation made using genomic and transcriptomic data, and particularly emphasize their adaptation to early land environments and modern ecosystems. Bryophytes including mosses, liverworts, and hornworts are among the earliest land plants, and occupy a crucial phylogenetic position to aid in the understanding of plant terrestrialization. Despite their small size and simple structure, bryophytes are the second largest group of extant land plants. They live ubiquitously in various habitats and are highly diversified, with adaptive strategies to modern ecosystems on Earth. More and more genomes and transcriptomes have been assembled to address fundamental questions in plant biology. Here, we review recent advances in bryophytes associated with diversity, phylogeny, and ecological adaptation. Phylogenomic studies have provided increasing supports for the monophyly of bryophytes, with hornworts sister to the Setaphyta clade including liverworts and mosses. Further comparative genomic analyses revealed that multiple whole-genome duplications might have contributed to the species richness and morphological diversity in mosses. We highlight that the biological changes through gene gain or neofunctionalization that primarily evolved in bryophytes have facilitated the adaptation to early land environments; among the strategies to adapt to modern ecosystems in bryophytes, desiccation tolerance is the most remarkable. More genomic information for bryophytes would shed light on key mechanisms for the ecological success of these 'dwarfs' in the plant kingdom.

Automated summary

This article reviews recent advances in bryophyte research, focusing on their diversity, phylogeny, and adaptation using genomic and transcriptomic data. Bryophytes are among the earliest land plants and play a crucial role in understanding plant terrestrialization. Despite their small size and simple structure, they are the second largest group of extant land plants, diversified and adapted to modern ecosystems. Genomic studies support their monophyly, with hornworts sister to liverworts and mosses. Whole-genome duplications contribute to moss species richness and morphological diversity. Gene gain or neofunctionalization in bryophytes has facilitated their adaptation to early land environments, with desiccation tolerance being the most remarkable strategy in adapting to modern ecosystems. More genomic information on bryophytes would enhance our understanding of their ecological success in the plant kingdom.