title: UV-B Inhibits Leaf Growth through Changes in Growth Regulating Factors and Gibberellin Levels.
abstract: Ultraviolet-B (UV-B) radiation affects leaf growth in a wide range of species. In this work, we demonstrate that UV-B levels present in solar radiation inhibit maize (Zea mays) leaf growth without causing any other visible stress symptoms, including the accumulation of DNA damage. We conducted kinematic analyses of cell division and expansion to understand the impact of UV-B radiation on these cellular processes. Our results demonstrate that the decrease in leaf growth in UV-B-irradiated leaves is a consequence of a reduction in cell production and a shortened growth zone (GZ). To determine the molecular pathways involved in UV-B inhibition of leaf growth, we performed RNA sequencing on isolated GZ tissues of control and UV-B-exposed plants. Our results show a link between the observed leaf growth inhibition and the expression of specific cell cycle and developmental genes, including growth-regulating factors (GRFs) and transcripts for proteins participating in different hormone pathways. Interestingly, the decrease in the GZ size correlates with a decrease in the concentration of GA19, the immediate precursor of the active gibberellin, GA1, by UV-B in this zone, which is regulated, at least in part, by the expression of GRF1 and possibly other transcription factors of the GRF family.
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos, Universidad Nacional de Rosario, Rosario S2002LRK, Argentina (J.F., R.C., P.C.).|Integrated Molecular Plant Physiology Research, Department of Biology, University of Antwerp, 2000 Antwerp, Belgium (H.A., E.P., M.N.M., G.T.S.B.); and.|Department of Botany and Microbiology, Faculty of Science, University of Beni-Suef, 62511 Beni-Suef, Egypt (H.A.).
authors.forename: Julieta
authors.initials: J
authors.lastname: Fina
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos, Universidad Nacional de Rosario, Rosario S2002LRK, Argentina (J.F., R.C., P.C.).|Integrated Molecular Plant Physiology Research, Department of Biology, University of Antwerp, 2000 Antwerp, Belgium (H.A., E.P., M.N.M., G.T.S.B.); and.|Department of Botany and Microbiology, Faculty of Science, University of Beni-Suef, 62511 Beni-Suef, Egypt (H.A.).
authors.forename: Romina
authors.identifier: http://orcid.org/0000-0003-1060-1857
authors.initials: R
authors.lastname: Casadevall
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos, Universidad Nacional de Rosario, Rosario S2002LRK, Argentina (J.F., R.C., P.C.).|Integrated Molecular Plant Physiology Research, Department of Biology, University of Antwerp, 2000 Antwerp, Belgium (H.A., E.P., M.N.M., G.T.S.B.); and.|Department of Botany and Microbiology, Faculty of Science, University of Beni-Suef, 62511 Beni-Suef, Egypt (H.A.).
authors.forename: Hamada
authors.initials: H
authors.lastname: AbdElgawad
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos, Universidad Nacional de Rosario, Rosario S2002LRK, Argentina (J.F., R.C., P.C.).|Integrated Molecular Plant Physiology Research, Department of Biology, University of Antwerp, 2000 Antwerp, Belgium (H.A., E.P., M.N.M., G.T.S.B.); and.|Department of Botany and Microbiology, Faculty of Science, University of Beni-Suef, 62511 Beni-Suef, Egypt (H.A.).
authors.forename: Els
authors.initials: E
authors.lastname: Prinsen
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos, Universidad Nacional de Rosario, Rosario S2002LRK, Argentina (J.F., R.C., P.C.).|Integrated Molecular Plant Physiology Research, Department of Biology, University of Antwerp, 2000 Antwerp, Belgium (H.A., E.P., M.N.M., G.T.S.B.); and.|Department of Botany and Microbiology, Faculty of Science, University of Beni-Suef, 62511 Beni-Suef, Egypt (H.A.).
authors.forename: Marios N
authors.identifier: http://orcid.org/0000-0001-5328-9694
authors.initials: MN
authors.lastname: Markakis
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos, Universidad Nacional de Rosario, Rosario S2002LRK, Argentina (J.F., R.C., P.C.).|Integrated Molecular Plant Physiology Research, Department of Biology, University of Antwerp, 2000 Antwerp, Belgium (H.A., E.P., M.N.M., G.T.S.B.); and.|Department of Botany and Microbiology, Faculty of Science, University of Beni-Suef, 62511 Beni-Suef, Egypt (H.A.).
authors.forename: Gerrit T S
authors.identifier: http://orcid.org/0000-0001-6014-053X
authors.initials: GTS
authors.lastname: Beemster
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos, Universidad Nacional de Rosario, Rosario S2002LRK, Argentina (J.F., R.C., P.C.); casati@cefobi-conicet.gov.ar.|Integrated Molecular Plant Physiology Research, Department of Biology, University of Antwerp, 2000 Antwerp, Belgium (H.A., E.P., M.N.M., G.T.S.B.); and casati@cefobi-conicet.gov.ar.|Department of Botany and Microbiology, Faculty of Science, University of Beni-Suef, 62511 Beni-Suef, Egypt (H.A.) casati@cefobi-conicet.gov.ar.
authors.forename: Paula
authors.identifier: http://orcid.org/0000-0002-3194-4683
authors.initials: P
authors.lastname: Casati
mesh_terms: D001696:Biomechanical Phenomena; D002455:Cell Division / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D005875:Gibberellins / Q000378:metabolism*; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D019441:Plant Epidermis / Q000166:cytology / Q000528:radiation effects; D010937:Plant Growth Regulators / Q000378:metabolism*; D018515:Plant Leaves / Q000254:growth & development* / Q000528:radiation effects*; D059467:Transcriptome / Q000235:genetics; D014466:Ultraviolet Rays; D003313:Zea mays / Q000235:genetics / Q000254:growth & development* / Q000528:radiation effects*
chemical_list: D005875:Gibberellins; D035683:MicroRNAs; D010937:Plant Growth Regulators