Produção de moléculas sinalizadoras em Solanum lycopersicum em resposta ao estresse salino

Abstract

Soil salinization is one of the factors that most decrease plant nutritional value and crop productivity. A better understanding of the biochemical mechanisms that drive plant tolerance to high salinity is valuable for the development of technologies to overcome the negative impact of this abiotic stress on agriculture. This work focuses on the extent of production of signaling molecules in Solanum lycopersicum cv. MT and MT yg-2 during the response to salt stress. The lower water and chlorophyll contents found in MT yg-2 plants confirm its phenotype as such genotype is defective for the biosynthesis of heme oxidase 1 (HO-1), involved in phytochrome production. NaCl treatment for 48 h induced the activity of the antioxidant enzymes catalase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD) in a salt concentration manner. Strikingly, the HO activity in MT yg-2 leaves were higher than that of its parental MT, suggesting that HO isoforms other than HO-1 are being stimulated during the abiotic stress. Additionally, 100 mM NaCl fastly induced CO accumulation in MT yg-2 plants when compared to the MT ones. Exogenous CO provided as CORM-2 induced the production of NO and H2S in roots and leaves of MT plants while only NO accumulation was recorded in yg-2 upon CORM-2 treatment. Overall, the differential response of MT yg-2 to CO regarding the stimulation of NO and H2S production during stress may partly explain the higher sensitiveness of MT yg-2 to high salinity than that of MT plants.