title: A Repressor Protein Complex Regulates Leaf Growth in Arabidopsis.
abstract: Cell number is an important determinant of final organ size. In the leaf, a large proportion of cells are derived from the stomatal lineage. Meristemoids, which are stem cell-like precursor cells, undergo asymmetric divisions, generating several pavement cells adjacent to the two guard cells. However, the mechanism controlling the asymmetric divisions of these stem cells prior to differentiation is not well understood. Here, we characterized PEAPOD (PPD) proteins, the only transcriptional regulators known to negatively regulate meristemoid division. PPD proteins interact with KIX8 and KIX9, which act as adaptor proteins for the corepressor TOPLESS. D3-type cyclin encoding genes were identified among direct targets of PPD2, being negatively regulated by PPDs and KIX8/9. Accordingly, kix8 kix9 mutants phenocopied PPD loss-of-function producing larger leaves resulting from increased meristemoid amplifying divisions. The identified conserved complex might be specific for leaf growth in the second dimension, since it is not present in Poaceae (grasses), which also lack the developmental program it controls.
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Gonzalez
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Laurens
authors.initials: L
authors.lastname: Pauwels
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Baekelandt
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Liesbeth
authors.initials: L
authors.lastname: De Milde
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Jelle
authors.identifier: http://orcid.org/0000-0002-4932-8192
authors.initials: J
authors.lastname: Van Leene
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Nienke
authors.initials: N
authors.lastname: Besbrugge
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Ken S
authors.identifier: http://orcid.org/0000-0001-5831-0536
authors.initials: KS
authors.lastname: Heyndrickx
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Amparo
authors.initials: A
authors.lastname: Cuéllar Pérez
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Astrid Nagels
authors.initials: AN
authors.lastname: Durand
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Rebecca
authors.identifier: http://orcid.org/0000-0002-4068-1811
authors.initials: R
authors.lastname: De Clercq
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Eveline
authors.identifier: http://orcid.org/0000-0003-2247-2976
authors.initials: E
authors.lastname: Van De Slijke
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Robin
authors.identifier: http://orcid.org/0000-0002-4593-9658
authors.initials: R
authors.lastname: Vanden Bossche
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Dominique
authors.identifier: http://orcid.org/0000-0001-5770-7670
authors.initials: D
authors.lastname: Eeckhout
authors.affiliation: Department of Medical Protein Research and Biochemistry, VIB, 9000 Ghent, Belgium Department of Biochemistry, Ghent University, 9000 Ghent, Belgium.
authors.forename: Kris
authors.identifier: http://orcid.org/0000-0002-4237-0283
authors.initials: K
authors.lastname: Gevaert
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Klaas
authors.identifier: http://orcid.org/0000-0003-4790-2725
authors.initials: K
authors.lastname: Vandepoele
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Geert
authors.identifier: http://orcid.org/0000-0001-6558-5669
authors.initials: G
authors.lastname: De Jaeger
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Alain
authors.identifier: http://orcid.org/0000-0002-1599-551X
authors.initials: A
authors.lastname: Goossens
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium dirk.inze@psb.vib-ugent.be.
authors.forename: Dirk
authors.identifier: http://orcid.org/0000-0002-3217-8407
authors.initials: D
authors.lastname: Inzé
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D056743:Cyclin D3 / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D046912:Multiprotein Complexes / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D018515:Plant Leaves / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D029681:Arabidopsis Proteins; D056743:Cyclin D3; D049452:Green Fluorescent Proteins; D046912:Multiprotein Complexes; D012097:Repressor Proteins; D014157:Transcription Factors; C000608386:KIX8 protein, Arabidopsis; C000608385:KIX9 protein, Arabidopsis; C000593019:TIFY4B protein, Arabidopsis; C511291:At1g15750 protein, Arabidopsis