You are here

Down-regulation of catalase activity allows transient accumulation of a hydrogen peroxide signal in Chlamydomonas reinhardtii

TitleDown-regulation of catalase activity allows transient accumulation of a hydrogen peroxide signal in Chlamydomonas reinhardtii
Publication TypeJournal Article
Year of Publication2013
AuthorsMichelet, L, Roach, T, Fischer, BB, Bedhomme, M, Lemaire, SD, Krieger-Liszkay, A
JournalPlant Cell Environ
Volume36
Pagination1204-13
Date PublishedJun
ISBN Number1365-3040 (Electronic)0140-7791 (Linking)
KeywordsCatalase/*antagonists & inhibitors/radiation effects, Chlamydomonas reinhardtii/*enzymology/genetics/radiation effects, Down-Regulation, Gene Expression Regulation, Plant, Hydrogen Peroxide/*metabolism, Light, Stress, Physiological
Abstract

In photosynthetic organisms, excess light is a stress that induces production of reactive oxygen species inside the chloroplasts. As a response, the capacity of antioxidative defence mechanisms increases. However, when cells of Chlamydomonas reinhardtii were shifted from dark to high light, a reversible partial inactivation of catalase activity was observed, which correlated with a transient increase in the level of H2 O2 in the 10 mum range. This concentration range seems to be necessary to activate H2 O2 -dependent signalling pathways stimulating the expression of H2 O2 responsive genes, such as the heat shock protein HSP22C. Catalase knock-down mutants had lost the transient accumulation of H2 O2 , suggesting that a decrease in catalase activity was the key element for establishing a transient H2 O2 burst. Catalase was inactivated by a one-electron event consistent with the reduction of a single cysteine. We propose that under high light intensity, the redox state of the photosynthetic electron transport chain is sensed and transmitted to the cytosol to regulate the catalase activity. This allows a transient accumulation of H2 O2 , inducing a signalling event that is transmitted to the nucleus to modulate the expression of chloroplast-directed protection enzymes.

URLhttp://www.ncbi.nlm.nih.gov/pubmed/23237476
Short TitlePlant, cell & environment