title: SPL8, a local regulator in a subset of gibberellin-mediated developmental processes in Arabidopsis.
abstract: Gibberellins (GAs) are important plant growth regulators, regulating many plant developmental processes, including seed germination, root and stem elongation, rosette expansion, floral induction and anther development. The diverse effects of GAs on plant development make it critical to maintain an appropriate endogenous GA level and a fine-tuned GA signalling. Some global regulators in GA signalling have been identified but little is known about genes specifically involved in local implementation of GA signalling. Here we report that the Arabidopsis thaliana SBP-box gene SQUAMOSA-PROMOTER-BINDING-PROTEIN-LIKE8 (SPL8) acts as a local regulator in a subset of GA-dependent developmental processes. Previous knowledge holds that SPL8 is involved in reproductive development as deduced from its loss-of-function phenotype (Unte et al. (2003) Plant Cell 15:1009-1019). We now determined that constitutive overexpression of SPL8 affects fertility due to non-dehiscent anthers, likely resulting from a constitutive GA response, suggesting a positive role of SPL8 in GA-mediated anther development. On the other hand, SPL8 gain- and loss-of-function mutants showed opposite responses to GA and its biosynthetic inhibitor paclobutrazol (PAC) with respect to seed germination and root elongation during the seedling stage. Genes involved in GA biosynthesis and signalling are transcriptionally affected by altered SPL8 expression. Our study uncovered a tissue-dependent regulatory role for SPL8 in the response to GA signalling in plant development.
authors.affiliation: Department of Molecular Plant Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Stefan
authors.initials: S
authors.lastname: Schwarz
authors.forename: Heinz
authors.initials: H
authors.lastname: Saedler
authors.forename: Peter
authors.initials: P
authors.lastname: Huijser
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D018744:DNA, Plant / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000187:drug effects / Q000254:growth & development; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000187:drug effects; D005875:Gibberellins / Q000378:metabolism / Q000494:pharmacology; D009154:Mutation; D010937:Plant Growth Regulators / Q000378:metabolism / Q000494:pharmacology; D030821:Plants, Genetically Modified; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D004268:DNA-Binding Proteins; D005875:Gibberellins; D010937:Plant Growth Regulators; C475164:SPL8 protein, Arabidopsis