Abiotic stress conditions, such as salt stress, water deficit, extreme temperatures, and high light, are the major factors that reduce plant growth and result in significant yield losses. Although plants have evolved a wide spectrum of pathways for sensing, responding, and adapting to changing environments, the current understanding of the mechanisms associated with the ability of crops to maintain yield under abiotic stress is poorly understood.

In plants, abiotic and biotic stresses usually interfere with the redox state of the cells and elicit generation of excess reactive oxygen and nitrogen species (ROS, RNS) that affect plant development under normal and stress conditions. Redox regulation and signaling is an essential feature of mitochondrial function in which thioredoxin Trxo1, involved in disulphide/dithiol interchange, and peroxiredoxin PrxIIF, involved in H2O2 and hydroperoxides detoxification, play an important role.

Our group has recently identified in pea plants a novel mitochondrial and nuclear PsTrxo1 that interacts with PrxIIF identified in mitochondria, which role mainly in the nucleus need to be elucidated. This proposal is aimed to explore the functions of antioxidant and redox systems in plant cell signaling using new advances in Omics technologies and plant cell technology to deeper inside in the scientific knowledge, particularly in the areas of fruit ripening, seed germination, and stress tolerance in crops such as tomato and pepper.

The implications of this work are large not only for understanding how plant redox signaling functions but also for enhancing our understanding of factors that can contribute to the production of improved plants with enhanced stress tolerance. Despite the importance of plant natural bioactive compounds (specifically secondary metabolites, antioxidant compounds, and redox proteins) for both people and plants, plant secondary metabolites continue to be a great unknown.

With the development of this project, we aim to clarify significant aspects of all of them, using elicited plant cell cultures. Any new knowledge acquired will be applied to enhance the biotechnological production of the bioactive compounds to be used in improving crop yields and fruit quality.

For that, the effects of some plant cell extracts with high content of those plant bioactive compounds will be used as a new strategy for strengthening both seed germination and abiotic stress tolerance. In addition, we extend our research to exploiting the potentiality of plant cell cultures, specifically those derived from crops which are interested for Murcia's Region, including pepper, tomato, and broccoli, to produce important secondary metabolites and proteins of potential interest to biotechnological applications in agrofood and pharmacological processes.

Particularly in human dermal fibroblasts and keratinocytes we will investigate the role of some selected plant cellular extracts enriched in the secondary metabolites, antioxidants, and/or Trxs, on inflammatory response induced by oxidative damage caused by H2O2 treatments and certain pollutant agents. The last two challenges will be used as a promising new approach to be carried out in our research group.

The proposed research implies the complementation of our expertise in plant physiology, cellular biology, proteomic, and molecular biology with expert groups in molecular genetics and clinical research which are going to collaborate with us. Finally, the Objectives proposed will also allow us important advances in our research activities and visibility in redox biology.

The progress will be focused on the knowledge of thioredoxin function in important and vital cell processes in plants, as well as to deep inside into the gene regulation of this redox protein due to the existing scarce information.