title: GROWTH REGULATING FACTOR5 stimulates Arabidopsis chloroplast division, photosynthesis, and leaf longevity.
abstract: Arabidopsis (Arabidopsis thaliana) leaf development relies on subsequent phases of cell proliferation and cell expansion. During the proliferation phase, chloroplasts need to divide extensively, and during the transition from cell proliferation to expansion, they differentiate into photosynthetically active chloroplasts, providing the plant with energy. The transcription factor GROWTH REGULATING FACTOR5 (GRF5) promotes the duration of the cell proliferation period during leaf development. Here, it is shown that GRF5 also stimulates chloroplast division, resulting in a higher chloroplast number per cell with a concomitant increase in chlorophyll levels in 35S:GRF5 leaves, which can sustain higher rates of photosynthesis. Moreover, 35S:GRF5 plants show delayed leaf senescence and are more tolerant for growth on nitrogen-depleted medium. Cytokinins also stimulate leaf growth in part by extending the cell proliferation phase, simultaneously delaying the onset of the cell expansion phase. In addition, cytokinins are known to be involved in chloroplast development, nitrogen signaling, and senescence. Evidence is provided that GRF5 and cytokinins synergistically enhance cell division and chlorophyll retention after dark-induced senescence, which suggests that they also cooperate to stimulate chloroplast division and nitrogen assimilation. Taken together with the increased leaf size, ectopic expression of GRF5 has great potential to improve plant productivity.
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); and Central European Institute of Technology, 60177 Brno, Czech Republic (V.B.T., A.B.).
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Vercruyssen
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); and Central European Institute of Technology, 60177 Brno, Czech Republic (V.B.T., A.B.).
authors.forename: Vanesa B
authors.initials: VB
authors.lastname: Tognetti
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); and Central European Institute of Technology, 60177 Brno, Czech Republic (V.B.T., A.B.).
authors.forename: Nathalie
authors.initials: N
authors.lastname: Gonzalez
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); and Central European Institute of Technology, 60177 Brno, Czech Republic (V.B.T., A.B.).
authors.forename: Judith
authors.initials: J
authors.lastname: Van Dingenen
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); and Central European Institute of Technology, 60177 Brno, Czech Republic (V.B.T., A.B.).
authors.forename: Liesbeth
authors.initials: L
authors.lastname: De Milde
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); and Central European Institute of Technology, 60177 Brno, Czech Republic (V.B.T., A.B.).
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Bielach
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); and Central European Institute of Technology, 60177 Brno, Czech Republic (V.B.T., A.B.).
authors.forename: Riet
authors.initials: R
authors.lastname: De Rycke
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); and Central European Institute of Technology, 60177 Brno, Czech Republic (V.B.T., A.B.).
authors.forename: Frank
authors.initials: F
authors.lastname: Van Breusegem
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (L.V., V.B.T., N.G., J.V.D., L.D.M., A.B., R.D.R., F.V.B., D.I.); and Central European Institute of Technology, 60177 Brno, Czech Republic (V.B.T., A.B.) dirk.inze@psb.vib-ugent.be.
authors.forename: Dirk
authors.initials: D
authors.lastname: Inzé
mesh_terms: D048948:14-3-3 Proteins / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D002455:Cell Division / Q000187:drug effects; D002734:Chlorophyll / Q000378:metabolism; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D003583:Cytokinins / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D009584:Nitrogen / Q000172:deficiency; D010788:Photosynthesis / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development / Q000502:physiology* / Q000648:ultrastructure; D030821:Plants, Genetically Modified; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*
chemical_list: D048948:14-3-3 Proteins; D003583:Cytokinins; C503422:GRF5 protein, Arabidopsis; D015534:Trans-Activators; D002734:Chlorophyll; D009584:Nitrogen