SUMO proteases ULP1c and ULP1d are required for development and osmotic stress responses in Arabidopsis thaliana.
Sumoylation is an essential post-translational regulator of plant development and the response to environmental stimuli. SUMO conjugation occurs via an E1-E2-E3 cascade, and can be removed by SUMO proteases (ULPs). ULPs are numerous and likely to function as sources of specificity within the pathway, yet most ULPs remain functionally unresolved. In this report we used loss-of-function reverse genetics and transcriptomics to functionally characterize Arabidopsis thaliana ULP1c and ULP1d SUMO proteases. GUS reporter assays implicated ULP1c/d in various developmental stages, and subsequent defects in growth and germination were uncovered using loss-of-function mutants. Microarray analysis evidenced not only a deregulation of genes involved in development, but also in genes controlled by various drought-associated transcriptional regulators. We demonstrated that ulp1c ulp1d displayed diminished in vitro root growth under low water potential and higher stomatal aperture, yet leaf transpirational water loss and whole drought tolerance were not significantly altered. Generation of a triple siz1 ulp1c ulp1d mutant suggests that ULP1c/d and the SUMO E3 ligase SIZ1 may display separate functions in development yet operate epistatically in response to water deficit. We provide experimental evidence that Arabidopsis ULP1c and ULP1d proteases act redundantly as positive regulators of growth, and operate mainly as isopeptidases downstream of SIZ1 in the control of water deficit responses.
Biosystems and Integrative Sciences Institute (BioISI), Plant Functional Biology Center, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.|Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento Biología Celular, Genética y Fisiología, Universidad de Málaga, Campus Teatinos, 29071, Malaga, Spain.|Section for Plant and Soil Science, Department of Plant and Environmental Sciences, University of Copenhagen, 1871, Frederiksberg C, Denmark.
Pedro Humberto
PH
Castro
Biosystems and Integrative Sciences Institute (BioISI), Plant Functional Biology Center, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.|The Sainsbury Laboratory, Colney Lane, Norwich, NR4 7UH, UK.
Daniel
D
Couto
Biosystems and Integrative Sciences Institute (BioISI), Plant Functional Biology Center, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
Sara
S
Freitas
Biosystems and Integrative Sciences Institute (BioISI), Plant Functional Biology Center, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
Nuno
N
Verde
Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento Biología Celular, Genética y Fisiología, Universidad de Málaga, Campus Teatinos, 29071, Malaga, Spain.|Shanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, 201602, Shanghai, China.
Alberto P
AP
Macho
Unité de Recherche en Génomique Végétale (URGV), UMR INRA 1165, Université d'Evry Val d'Essonne, ERL CNRS 8196, 2 rue G. Crémieux, CP 5708, 91057, Evry Cedex, France.
Stéphanie
S
Huguet
Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento Biología Molecular y Bioquímica, Universidad de Málaga, Campus Teatinos, 29071, Malaga, Spain.
Miguel Angel
MA
Botella
Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento Biología Celular, Genética y Fisiología, Universidad de Málaga, Campus Teatinos, 29071, Malaga, Spain.
Javier
J
Ruiz-Albert
Biosystems and Integrative Sciences Institute (BioISI), Plant Functional Biology Center, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
Rui Manuel
RM
Tavares
Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento Biología Celular, Genética y Fisiología, Universidad de Málaga, Campus Teatinos, 29071, Malaga, Spain.
Eduardo Rodríguez
ER
Bejarano
CIBIO, InBIO-Research Network in Biodiversity and Evolutionary Biology, Universidade do Porto, Campus Agrário de Vairão, 4485-661, Vairão, Portugal. hazevedo@cibio.up.pt.
Herlânder
H
Azevedo
D000040:Abscisic Acid / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018525:Germination / Q000187:drug effects / Q000502:physiology; D064587:Osmoregulation / Q000187:drug effects / Q000502:physiology*
D029681:Arabidopsis Proteins; D000040:Abscisic Acid
ABA; Osmotic stress; Plant development; SIZ1; SUMO proteases; Stomatal aperture