title: Tightly controlled WRKY23 expression mediates Arabidopsis embryo development.
abstract: The development of a multicellular embryo from a single zygote is a complex and highly organized process that is far from understood. In higher plants, apical-basal patterning mechanisms are crucial to correctly specify root and shoot stem cell niches that will sustain and drive post-embryonic plant growth and development. The auxin-responsive AtWRKY23 transcription factor is expressed from early embryogenesis onwards and the timing and localization of its expression overlaps with the root stem cell niche. Knocking down WRKY23 transcript levels or expression of a dominant-negative WRKY23 version via a translational fusion with the SRDX repressor domain affected both apical-basal axis formation as well as installation of the root stem cell niche. WRKY23 expression is affected by two well-known root stem cell specification mechanisms, that is, SHORTROOT and MONOPTEROS-BODENLOS signalling and can partially rescue the root-forming inability of mp embryos. On the basis of these results, we postulate that a tightly controlled WRKY23 expression is involved in the regulation of both auxin-dependent and auxin-independent signalling pathways towards stem cell specification.
authors.affiliation: 1] Department of Plant Systems Biology, VIB, and Bioinformatics, Ghent University, 9052 Ghent, Belgium [2] Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Wim
authors.initials: W
authors.lastname: Grunewald
authors.forename: Ive
authors.initials: I
authors.lastname: De Smet
authors.forename: Bert
authors.initials: B
authors.lastname: De Rybel
authors.forename: Helene S
authors.initials: HS
authors.lastname: Robert
authors.forename: Brigitte
authors.initials: B
authors.lastname: van de Cotte
authors.forename: Viola
authors.initials: V
authors.lastname: Willemsen
authors.forename: Godelieve
authors.initials: G
authors.lastname: Gheysen
authors.forename: Dolf
authors.initials: D
authors.lastname: Weijers
authors.forename: Jiří
authors.initials: J
authors.lastname: Friml
authors.forename: Tom
authors.initials: T
authors.lastname: Beeckman
mesh_terms: D017360:Arabidopsis / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism; D018519:Meristem / Q000196:embryology / Q000378:metabolism; D055153:Stem Cell Niche; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D014157:Transcription Factors; C532783:WRKY23 protein, Arabidopsis