title: Subunits B'γ and B'ζ of protein phosphatase 2A regulate photo-oxidative stress responses and growth in Arabidopsis thaliana.
abstract: Plants survive periods of unfavourable conditions with the help of sensory mechanisms that respond to reactive oxygen species (ROS) as signalling molecules in different cellular compartments. We have previously demonstrated that protein phosphatase 2A (PP2A) impacts on organellar cross-talk and associated pathogenesis responses in Arabidopsis thaliana. This was evidenced by drastically enhanced pathogenesis responses and cell death in cat2 pp2a-b'γ double mutants, deficient in the main peroxisomal antioxidant enzyme CATALASE 2 and PP2A regulatory subunit B'γ (PP2A-B'γ). In the present paper, we explored the impacts of PP2A-B'γ and a highly similar regulatory subunit PP2A-B'ζ in growth regulation and light stress tolerance in Arabidopsis. PP2A-B'γ and PP2A-B'ζ display high promoter activities in rapidly growing tissues and are required for optimal growth under favourable conditions. Upon acclimation to a combination of high light, elevated temperature and reduced availability of water, however, pp2a-b'γζ double mutants grow similarly to the wild type and show enhanced tolerance against photo-oxidative stress. We conclude that by controlling ROS homeostasis and signalling, PP2A-B'γ and PP2A-B'ζ may direct acclimation strategies upon environmental perturbations, hence acting as important determinants of defence responses and light acclimation in plants.
authors.affiliation: Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014, Turku, Finland.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Konert
authors.affiliation: Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014, Turku, Finland.
authors.forename: Moona
authors.initials: M
authors.lastname: Rahikainen
authors.affiliation: Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014, Turku, Finland.
authors.forename: Andrea
authors.initials: A
authors.lastname: Trotta
authors.affiliation: Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014, Turku, Finland.
authors.forename: Guido
authors.initials: G
authors.lastname: Durian
authors.affiliation: Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland.
authors.forename: Jarkko
authors.initials: J
authors.lastname: Salojärvi
authors.affiliation: Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014, Turku, Finland.
authors.forename: Sergey
authors.initials: S
authors.lastname: Khorobrykh
authors.affiliation: Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014, Turku, Finland.
authors.forename: Esa
authors.initials: E
authors.lastname: Tyystjärvi
authors.affiliation: Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014, Turku, Finland.
authors.forename: Saijaliisa
authors.initials: S
authors.lastname: Kangasjärvi
mesh_terms: D000064:Acclimatization; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D017930:Genes, Reporter; D006706:Homeostasis; D008027:Light; D009154:Mutation; D018384:Oxidative Stress; D010766:Phosphorylation; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D054648:Protein Phosphatase 2 / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits; D017382:Reactive Oxygen Species / Q000378:metabolism; D036226:Seedlings / Q000201:enzymology / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D013312:Stress, Physiological
chemical_list: D029681:Arabidopsis Proteins; D021122:Protein Subunits; D017382:Reactive Oxygen Species; D054648:Protein Phosphatase 2
keywords: PP2A; growth regulation; light acclimation; reactive oxygen species (ROS); signalling