A Repressor Protein Complex Regulates Leaf Growth in Arabidopsis. Issue 8 (31st July 2015)

• Record Type: Journal Article
• Authors: Gonzalez, Nathalie; Pauwels, Laurens; Baekelandt, Alexandra; De Milde, Liesbeth; Van Leene, Jelle; Besbrugge, Nienke; Heyndrickx, Ken S.; Pérez, Amparo Cuéllar; Durand, Astrid Nagels; De Clercq, Rebecca; Van De Slijke, Eveline; Vanden Bossche, Robin; Eeckhout, Dominique; Gevaert, Kris; Vandepoele, Klaas; De Jaeger, Geert; Goossens, Alain; Inzé, Dirk
• Is Part Of: The Plant Cell. Volume 27:Issue 8(2015)
• Page Start: 2273
• Page End: 2287
• Publication Date: 2015-07-31
• DOI: 10.1105/tpc.15.00006
• Languages: English
• ISSNs: 1040-4651

Abstract

Abstract : PPD2 interacts with KIX8 and KIX9 proteins to regulate the transcription of its target genes, including the CYCD3s, and helps to control final leaf size 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.