The origin and early evolution of plants

Highlights The origin of the first photosynthetic eukaryotes through to the first land plants transformed the Earth's biosphere. There is no single unified view of the processes and timing of early plant evolution despite myriad fossil and geochemical evidence. Phylogenetically targeted genomic, morphological, and Earth system data will be necessary to make significant advances in our understanding of early plant evolution given the deep timescales. Abstract Plant (archaeplastid) evolution transformed the biosphere but we are only now beginning to learn how through comparative genomics, phylogenetics and the fossil record. This has illuminated the phylogeny of Archaeplastida, Viridiplantae and Streptophyta, resolving the evolution of key characters, genes and genomes revealing many key innovations to have evolved long before the clades with which they have been casually associated. Molecular clock analyses estimate Streptophyta and Viridiplantae to have emerged in the late Mesoproterozoic-late Neoproterozoic, Archaeplastida in the late-mid Palaeoproterozoic. Together, these insights inform on the coevolution of plants and the Earth system, transforming ecology and global biogeochemical cycles, increasing weathering and precipitating snowball Earth events during which they would have been key to oxygen production and net primary productivity.