title: Origins and Evolution of Stomatal Development.
abstract: The fossil record suggests stomata-like pores were present on the surfaces of land plants over 400 million years ago. Whether stomata arose once or whether they arose independently across newly evolving land plant lineages has long been a matter of debate. In Arabidopsis, a genetic toolbox has been identified that tightly controls stomatal development and patterning. This includes the basic helix-loop-helix (bHLH) transcription factorsSPEECHLESS(SPCH),MUTE,FAMA, andICE/SCREAMs(SCRMs), which promote stomatal formation. These factors are regulated via a signaling cascade, which includes mobileEPIDERMAL PATTERNING FACTOR(EPF) peptides to enforce stomatal spacing. Mosses and hornworts, the most ancient extant lineages to possess stomata, possess orthologs of these Arabidopsis (Arabidopsis thaliana) stomatal toolbox genes, and manipulation in the model bryophytePhyscomitrella patenshas shown that the bHLH and EPF components are also required for moss stomatal development and patterning. This supports an ancient and tightly conserved genetic origin of stomata. Here, we review recent discoveries and, by interrogating newly available plant genomes, we advance the story of stomatal development and patterning across land plant evolution. Furthermore, we identify potential orthologs of the key toolbox genes in a hornwort, further supporting a single ancient genetic origin of stomata in the ancestor to all stomatous land plants.
authors.affiliation: Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de Mexico, Cuernavaca 62210, Mexico (C.C.C.C.); c.chater@sheffield.ac.uk.|Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom (R.S.C., J.E.G.); and c.chater@sheffield.ac.uk.|Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom (A.J.F.) c.chater@sheffield.ac.uk.
authors.forename: Caspar C C
authors.identifier: http://orcid.org/0000-0003-2058-2020
authors.initials: CCC
authors.lastname: Chater
authors.affiliation: Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de Mexico, Cuernavaca 62210, Mexico (C.C.C.C.).|Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom (R.S.C., J.E.G.); and.|Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom (A.J.F.).
authors.forename: Robert S
authors.identifier: http://orcid.org/0000-0002-6480-218X
authors.initials: RS
authors.lastname: Caine
authors.affiliation: Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de Mexico, Cuernavaca 62210, Mexico (C.C.C.C.).|Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom (R.S.C., J.E.G.); and.|Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom (A.J.F.).
authors.forename: Andrew J
authors.identifier: http://orcid.org/0000-0002-9703-0745
authors.initials: AJ
authors.lastname: Fleming
authors.affiliation: Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de Mexico, Cuernavaca 62210, Mexico (C.C.C.C.).|Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom (R.S.C., J.E.G.); and.|Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom (A.J.F.).
authors.forename: Julie E
authors.identifier: http://orcid.org/0000-0001-9972-5156
authors.initials: JE
authors.lastname: Gray
mesh_terms: D017360:Arabidopsis / Q000502:physiology; D005075:Biological Evolution; D044002:Bryophyta / Q000502:physiology; D019068:Bryopsida / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D015233:Models, Statistical; D005810:Multigene Family; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D054046:Plant Stomata / Q000502:physiology*
chemical_list: D010940:Plant Proteins