Aro, Eva-Mari

Hiltunen, Hanna-Maija

Holmström, Maija

Kangasjärvi, Saijaliisa Maria

Konert, Grzegorz

Mulo, Paula

Rahikainen, Moona Mariia

Rips, Stephan

Scharte, Judith

Sipari, Nina

Tikkanen, Mikko

Trotta, Andrea

von Schaewen, Antje

Weis, Engelbert

Wrzaczek, Michael

PubMed

Abstract
               Light is an important environmental factor that modulates acclimation strategies and defense responses in plants. We explored the functional role of the regulatory subunit B′γ (B′γ) of protein phosphatase 2A (PP2A) in light-dependent stress responses of Arabidopsis (Arabidopsis thaliana). The predominant form of PP2A consists of catalytic subunit C, scaffold subunit A, and highly variable regulatory subunit B, which determines the substrate specificity of PP2A holoenzymes. Mutant leaves of knockdown pp2a-b′γ plants show disintegration of chloroplasts and premature yellowing conditionally under moderate light intensity. The cell-death phenotype is accompanied by the accumulation of hydrogen peroxide through a pathway that requires CONSTITUTIVE EXPRESSION OF PR GENES5 (CPR5). Moreover, the pp2a-b′γ cpr5 double mutant additionally displays growth suppression and malformed trichomes. Similar to cpr5, the pp2a-b′γ mutant shows constitutive activation of both salicylic acid- and jasmonic acid-dependent defense pathways. In contrast to cpr5, however, pp2a-b′γ leaves do not contain increased levels of salicylic acid or jasmonic acid. Rather, the constitutive defense response associates with hypomethylation of DNA and increased levels of methionine-salvage pathway components in pp2a-b′γ leaves. We suggest that the specific B′γ subunit of PP2A is functionally connected to CPR5 and operates in the basal repression of defense responses under low irradiance.</jats:p

Andrea Trotta

Michael Wrzaczek

Judith Scharte

Mikko Tikkanen

Grzegorz Konert

Moona Rahikainen

Maija Holmström

Hanna-Maija Hiltunen

Stephan Rips

Nina Sipari

Paula Mulo

Engelbert Weis

Antje von Schaewen

Eva-Mari Aro

Saijaliisa Kangasjärvi

Crossref

Regulatory Subunit B′γ of Protein Phosphatase 2A Prevents Unnecessary Defense Reactions under Low Light in Arabidopsis
 
 

Helsingin yliopiston digitaalinen arkisto

Regulatory subunit B'gamma of protein phosphatase 2A prevents unnecessary defense reactions under low light in Arabidopsis

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=3135915

Regulatory subunit B'gamma of protein phosphatase 2A prevents unnecessary defense reactions under low light in Arabidopsis

Abstract

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Helsingin yliopiston digitaalinen arkisto