Influence of nitric oxide (NO) manipulation in responses to different stresses in tomato

Abstract

Tomato (Solanum lycopersicum) is one of the most cultivated vegetable plants in the world; however, adverse environmental conditions, both biotic and abiotic, are known to cause causing significant productivity and quality losses in this crop species. Signaling compounds, such as Nitric Oxide (NO), have been successfully used in some plants to improve their response to abiotic stress conditions. However, applying NO donors to plants growing under field conditions is currently one of the main barriers to the biotechnological use of this signaling molecule, since such donors are inherently instable and their decomposition dynamics are highly influenced by the surrounding environmental conditions. In this sense, the nanoencapsulation of NO donors has recently emerged as a promising alternative for improving the physicochemical properties of these substances, providing increased bioavailability and treatment efficacy. Another biotechnological alternative to achieve this goal consists in genetically engineering the S-nitrosoglutathione (GSNO) endogenous levels in plants cells. In this context, manipulation of levels and activity of the GSNO reductase (GSNOR) enzyme, which is responsible for the removal of GSNO from plant cells, emerges as one of the most promising approaches to genetic manipulation for temporal and quantitative adjustment of GSNO/NO levels within plant tissues. In spite of its agronomic importance and its role as a model species on fleshy fruits, relatively few studies have been carried out on the manipulation of endogenous levels of GSNO/NO in tomato, aiming at increasing its resistance to stress conditions. In this context, the present work aims to: (i) characterize the impacts of GSNOR overexpression and silencing on tomato vegetative development and fruit production under high temperature and drought conditions and under pathogen infection; (ii) compare the efficacy of NO-3NPs with that offered by non-encapsulated NO donors in mitigating the deleterious effects of these biotic and abiotic stresses. Physiological, biochemical and molecular approaches will be used to identify NO-controlled genes, proteins and metabolic processes during the vegetative and reproductive development of tomato plants under optimal growth conditions as well as in the presence of environmental stresses critical for this crop. (AU)