title: SUMO proteases OTS1 and 2 control filament elongation through a DELLA-dependent mechanism.
abstract: SUMOylation and anther growth. During fertilization, stamen elongation needs to be synchronized with pistil growth. The phytohormone gibberellic acid (GA) promotes stamen growth by stimulating the degradation of growth repressing DELLA proteins. DELLA accumulation is negatively regulated by GAs through the ubiquitin-proteasome system. In Arabidopsis thaliana, a proportion of DELLAs is also conjugated to the small ubiquitin-like modifier (SUMO) protein, which stabilizes DELLAs. Increased DELLA levels occur in the SUMO protease-deficient OVERLY TOLERANT TO SALT 1 and 2 (ots1 ots2) double mutants, especially under salt stress conditions. Here, we show that OTS genes play a redundant role in the control of plant fertility under non-stress conditions. Mutants of ots1 ots2 display reduced fertility compared with the wild type, owing to reduced stamen elongation. Stamen growth, pollination rate and seed production are restored in ots1 ots2 della mutants, thus linking OTS1 function to the control of DELLA activity in the context of filament elongation. OTS levels appear to be developmentally regulated as OTS1/2 transcript upregulation during stamen development overlaps with GAs accumulations. We propose that OTS genes enable synchronization of stamen development by facilitating DELLA degradation at a specific developmental stage.
authors.affiliation: Department of Biosciences, Università degli studi di Milano, Milan, Italy.|Biological and Biomedical Sciences, Durham University, Durham, DH1 3LE, UK.
authors.forename: Alberto
authors.initials: A
authors.lastname: Campanaro
authors.affiliation: Department of Biosciences, Università degli studi di Milano, Milan, Italy.|CREA - Genomics Research Centre, Fiorenzuola d'Arda, PC, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Battaglia
authors.affiliation: Department of Biosciences, Università degli studi di Milano, Milan, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Galbiati
authors.affiliation: Biological and Biomedical Sciences, Durham University, Durham, DH1 3LE, UK.
authors.forename: Ari
authors.initials: A
authors.lastname: Sadanandom
authors.affiliation: Department of Biosciences, Università degli studi di Milano, Milan, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Tonelli
authors.affiliation: Department of Biosciences, Università degli studi di Milano, Milan, Italy. Lucio.Conti@unimi.it.
authors.forename: Lucio
authors.identifier: http://orcid.org/0000-0002-7837-4227
authors.initials: L
authors.lastname: Conti
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism*; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D005875:Gibberellins / Q000378:metabolism; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism*; D058207:Sumoylation; D025801:Ubiquitin / Q000378:metabolism; D014452:Ubiquitins / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C109555:GAI protein, Arabidopsis; D005875:Gibberellins; D010937:Plant Growth Regulators; C403233:SUMO protein, plant; D025801:Ubiquitin; D014452:Ubiquitins; C007842:gibberellic acid; D010447:Peptide Hydrolases; D003546:Cysteine Endopeptidases; C535127:OTS1 protein, Arabidopsis; C535128:OTS2 protein, Arabidopsis
keywords: DELLA; Flower development; Gibberellin; SUMO proteases; SUMOylation