Characterization of the Arabidopsis thaliana 2-Cys peroxiredoxin interactome

Peroxiredoxins are ubiquitous thiol-dependent peroxidases for which chaperone and signaling roles havebeen reported in various types of organisms in recent years. In plants, the peroxidase function of thetwo typical plastidial 2-Cys peroxiredoxins (2-Cys PRX A and B) has been highlighted while the otherfunctions, particularly in ROS-dependent signaling pathways, are still elusive notably due to the lack ofknowledge of interacting partners. Using an ex vivo approach based on co-immunoprecipitation of leafextracts from Arabidopsis thaliana wild-type and mutant plants lacking 2-Cys PRX expression followedby mass spectrometry-based proteomics, 158 proteins were found associated with 2-Cys PRXs. Alreadyknown partners like thioredoxin-related electron donors (Chloroplastic Drought-induced Stress Proteinof 32 kDa, Atypical Cysteine Histidine-rich Thioredoxin 2) and enzymes involved in chlorophyll synthe-sis (Protochlorophyllide OxidoReductase B) or carbon metabolism (Fructose-1,6-BisPhosphatase) wereidentified, validating the relevance of the approach. Bioinformatic and bibliographic analyses allowedthe functional classification of the identified proteins and revealed that more than 40% are localized inplastids. The possible roles of plant 2-Cys PRXs in redox signaling pathways are discussed in relation withthe functions of the potential partners notably those involved in redox homeostasis, carbon and aminoacid metabolisms as well as chlorophyll biosynthesis.