title: Catalase and NO CATALASE ACTIVITY1 promote autophagy-dependent cell death in Arabidopsis.
abstract: Programmed cell death often depends on generation of reactive oxygen species, which can be detoxified by antioxidative enzymes, including catalases. We previously isolated catalase-deficient mutants (cat2) in a screen for resistance to hydroxyurea-induced cell death. Here, we identify an Arabidopsis thaliana hydroxyurea-resistant autophagy mutant, atg2, which also shows reduced sensitivity to cell death triggered by the bacterial effector avrRpm1. To test if catalase deficiency likewise affected both hydroxyurea and avrRpm1 sensitivity, we selected mutants with extremely low catalase activities and showed that they carried mutations in a gene that we named NO CATALASE ACTIVITY1 (NCA1). nca1 mutants showed severely reduced activities of all three catalase isoforms in Arabidopsis, and loss of NCA1 function led to strong suppression of RPM1-triggered cell death. Basal and starvation-induced autophagy appeared normal in the nca1 and cat2 mutants. By contrast, autophagic degradation induced by avrRpm1 challenge was compromised, indicating that catalase acted upstream of immunity-triggered autophagy. The direct interaction of catalase with reactive oxygen species could allow catalase to act as a molecular link between reactive oxygen species and the promotion of autophagy-dependent cell death.
authors.affiliation: Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hackenberg
authors.forename: Trine
authors.initials: T
authors.lastname: Juul
authors.forename: Aija
authors.initials: A
authors.lastname: Auzina
authors.forename: Sonia
authors.initials: S
authors.lastname: Gwizdz
authors.forename: Anna
authors.initials: A
authors.lastname: Malolepszy
authors.forename: Katrien
authors.initials: K
authors.lastname: Van Der Kelen
authors.forename: Svend
authors.initials: S
authors.lastname: Dam
authors.forename: Simon
authors.initials: S
authors.lastname: Bressendorff
authors.forename: Andrea
authors.initials: A
authors.lastname: Lorentzen
authors.forename: Peter
authors.initials: P
authors.lastname: Roepstorff
authors.forename: Kåre
authors.initials: K
authors.lastname: Lehmann Nielsen
authors.forename: Jan-Elo
authors.initials: JE
authors.lastname: Jørgensen
authors.forename: Daniel
authors.initials: D
authors.lastname: Hofius
authors.forename: Frank
authors.initials: F
authors.lastname: Van Breusegem
authors.forename: Morten
authors.initials: M
authors.lastname: Petersen
authors.forename: Stig Uggerhøj
authors.initials: SU
authors.lastname: Andersen
mesh_terms: D000626:Aminopeptidases / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001343:Autophagy / Q000187:drug effects / Q000502:physiology*; D000071183:Autophagy-Related Proteins; D001426:Bacterial Proteins / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002374:Catalase / Q000235:genetics / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects / Q000235:genetics; D006918:Hydroxyurea / Q000494:pharmacology; D009154:Mutation; D018384:Oxidative Stress
chemical_list: D029681:Arabidopsis Proteins; D000071183:Autophagy-Related Proteins; C502082:AvrRpm1 protein, Pseudomonas syringae; D001426:Bacterial Proteins; D002352:Carrier Proteins; C568852:NBR1 protein, Arabidopsis; C490276:CAT2 protein, Arabidopsis; D002374:Catalase; D000626:Aminopeptidases; C518661:Atg2 protein, Arabidopsis; D006918:Hydroxyurea