title: Repression of BLADE-ON-PETIOLE genes by KNOX homeodomain protein BREVIPEDICELLUS is essential for differentiation of secondary xylem in Arabidopsis root.
abstract: Repression of boundary genes by KNOTTED1-like homeodomain transcription factor BREVIPEDICELLUS promotes the differentiation of phase II secondary xylem in Arabidopsis roots. Plant growth and development relies on the activity of meristems. Boundaries are domains of restricted growth that separate forming organs and the meristem. Class I KNOX homeodomain transcription factors are important regulators of meristem maintenance. Members of this class including BREVIDICELLUS also called KNOTTED-LIKE FROM ARABIDOPSIS THALIANA1 (BP/KNAT1) fulfill this function in part by spatially regulating boundary genes. The vascular cambium is a lateral meristem that allows for radial expansion of organs during secondary growth. We show here that BP/KNAT1 repression of boundary genes plays a crucial role in root secondary growth. In particular, exclusion of BLADE-ON-PETIOLE1/2 (BOP1/2) and other members of this module from xylem is required for the differentiation of lignified fibers and vessels during the xylem expansion phase of root thickening. These data reveal a previously undiscovered role for boundary genes in the root and shed light on mechanisms controlling wood development in trees.
authors.affiliation: Department of Biology and Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada.|Institut Jean-Pierre Bourgin, UMR1318, INRA, Agro Paris Tech, CNRS, Université Paris-Saclay, RD10, 78026, Versailles Cedex, France.
authors.forename: Natalie
authors.initials: N
authors.lastname: Woerlen
authors.affiliation: Department of Biology and Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada.
authors.forename: Gamalat
authors.initials: G
authors.lastname: Allam
authors.affiliation: Department of Biology and Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada.|Institut Jean-Pierre Bourgin, UMR1318, INRA, Agro Paris Tech, CNRS, Université Paris-Saclay, RD10, 78026, Versailles Cedex, France.
authors.forename: Adina
authors.initials: A
authors.lastname: Popescu
authors.affiliation: Department of Biology and Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada.
authors.forename: Laura
authors.initials: L
authors.lastname: Corrigan
authors.affiliation: Institut Jean-Pierre Bourgin, UMR1318, INRA, Agro Paris Tech, CNRS, Université Paris-Saclay, RD10, 78026, Versailles Cedex, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Pautot
authors.affiliation: Department of Biology and Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada. shelley_hepworth@carleton.ca.
authors.forename: Shelley R
authors.identifier: http://orcid.org/0000-0002-6496-3792
authors.initials: SR
authors.lastname: Hepworth
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism*; D052584:Xylem / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; C092212:KNAT1 protein, Arabidopsis; C095848:Kn1 protein, plant; D010940:Plant Proteins
keywords: ARABIDOPSIS THALIANA HOMEOBOX GENE1; Arabidopsis thaliana; BLADE-ON-PETIOLE1/2; BREVIPEDICELLUS/KNAT1; KNOTTED1-LIKE FROM ARABIDOPSIS THALIANA6; Lignin; Root; Secondary growth; Xylem