Proteomic profiling of peroxisomal proteins in the ripening of sweet pepper (Capsicum annuum L.) fruit. Catalase as a case study

ABSTRACT: Fruit ripening is a very important physiological process which gains relevance in crop species due to their economical and nutritional repercussions. During fruit ripening enormous metabolic changes occur in a genetically-controlled scenario affecting the physiology of most cell compartments. Peroxisomes are single-membrane bounded organelles present in all eukaryotes which display a noteworthy nitro-oxidative metabolism, and harbor catalase as one of the major antioxidant enzymes in cells. Quantitative proteomics analysis by isobaric tags for relative and absolute quantification (iTRAQ) was used to investigate the ripening process in sweet pepper (Capsicum annuum L.) fruits. Out of 2,574 quantified proteins, 692 were found to be significantly more abundant in immature green fruits compared to red ones, but 497 showed a lower expression as the ripening proceeded. Overall, about 50% of the detectable proteins were estimated to modify their expression due to the ripening process. Data obtained from the Gene Ontology algorithms (AgriGO platform) showed that from all the identified proteins, 46 (2%) were only predicted to have a peroxisomal origin, with a high number of them displaying up-expression tendency during ripening. Catalase was framed within the group which showed lower expression in ripe fruits, but this enzyme was also susceptible to undergo posttranslational modifications (PTMs) promoted by reactive nitrogen and oxygen species (RNS and ROS) through nitration, S-nitrosylation and oxidation events which provoked its inhibition. The biochemical characterization of catalase indicates that it has atypical native molecular mass (125-135 kDa), since it behaves as a homodimer, and isoelectric point of 7.4, which is higher than that of the majority of plant catalases reported so far. Taking together, these data suggest that ROS and RNS could be essential to modulate the role of catalase for the maintenance of basic cellular peroxisomal functions during pepper fruit ripening where nitro-oxidative stress occur.

INSTRUMENT(S): TripleTOF 5600

ORGANISM(S): Capsicum Annuum

TISSUE(S): Pericarp

SUBMITTER: Antonio Ramos Fernández  

LAB HEAD: José Manuel Palma Martínez

PROVIDER: PXD010457 | Pride | 2022-05-19

REPOSITORIES: Pride