Auxin controls virtually all facets of growth and development. This plant hormone is sensed by TIR1/AFB F-box receptors which promote ubiquitin-mediated degradation of AUX/IAA transcriptional repressors, releasing ARF transcription factors from inhibition. Phylogenetic analyses divide the ARF family into three conserved classes: A/B/C, where A-ARFs act as activators, with some B and C-ARFs acting as […]
Streptophytes are a grade of mostly freshwater algae that transitioned into land, a singularity that in turn gave rise to all present terrestrial flora. This passage along the hydrological gradient that culminated in land habitation required key adaptations to overcome previously unencountered terrestrial stressors such as UV radiation, and hydric and temperature stress. In this […]
Colonization of the terrestrial environment by land plants (embryophytes), a monophyletic clade that evolved from freshwater streptophyte algae, forever changed Earth by transforming biogeochemical cycles. The evolution of stomata was a key adaptation that allowed the colonization of terra firma. Present in most land plants, stomata control the passage of carbon dioxide and water vapor, […]
In multicellular organisms, the patterning of different cell types in spatial arrays is regulated through several mechanisms, one of which is lateral inhibition, a process well characterized in metazoans. In this process, an individual cell transmits signals to neighboring cells to instruct a different cell fate to that of the instructing cell. In plants, lateral […]
The vascular cambium, a meristematic tissue responsible for xylem and phloem production, is an ancestral trait in angiosperms, however, its loss has independently occurred in at least 5 flowering plant lineages. One of such is the Nymphaeales, which includes Nymphaea thermarum, an emergent model for early flowering plant evolution. Studies in several species have determined […]
Plant cells are entrapped in rigid cell walls, so morphogenesis relies on asymmetric cell division (ACD) and positional cues to regulate tissue patterning. The Arabidopsis phloem is a good system to study tissue patterning due to its relatively simple composition: sieve elements (SEs) and companion cells (CCs) lineages. Although the regulatory programs that control phloem […]
Plants are constantly exposed to biotic and biotic stresses that can cause tissue damage, and, as a response, plants have evolved remarkably plastic regenerative mechanisms in response to wounding. Although some genes required for regeneration have been identified in the Arabidopsis root context, most notably PLETHORA (PLT) genes, the molecular players required for wound repair […]