Ascorbate peroxidase postcold regulation of chloroplast NADPH dehydrogenase activity controls cold memory.

Exposure of Arabidopsis (Arabidopsis thaliana) to 4°C imprints a cold memory that modulates gene expression in response to a second (triggering) stress stimulus applied several days later. Comparison of plastid transcriptomes of cold-primed and control plants directly before they were exposed to the triggering stimulus showed downregulation of several subunits of chloroplast NADPH dehydrogenase (NDH) and regulatory subunits of ATP synthase. NDH is, like proton gradient 5 (PGR5)-PGR5-like1 (PGRL1), a thylakoid-embedded, ferredoxin-dependent plastoquinone reductase that protects photosystem I and stabilizes ATP synthesis by cyclic electron transport (CET).

The Plant Immunity Regulating F-Box Protein Supports Plastid Function in Absence of Pathogens.

The mutant ( of was isolated in a genetic screening approach for mutants with defects in chloroplast-to-nucleus redox signaling. It has an atypically low activation status of the 2-Cys peroxiredoxin-A promoter in the seedling stage. shows wildtype-like germination, seedling development and greening, but slower growth and reduced biomass in the rosette stage.

Specificity versus redundancy in the RAP2.4 transcription factor family of Arabidopsis thaliana: transcriptional regulation of genes for chloroplast peroxidases.

Background: The Arabidopsis ERFIb / RAP2.4 transcription factor family consists of eight members with highly conserved DNA binding domains. Selected members have been characterized individually, but a systematic comparison is pending.