Understanding tolerance mechanisms of NO alleviating alkaline stress in tomato

STEELHEART, CHARLOTTE; GANGANELLI, INTI M; ALEGRE, MATÍAS LEONEL; GERGOFF GROZEFF, GUSTAVO E.; BARTOLI, CARLOS GUILLERMO

Rosario

Congreso; XXXIV Reunión de la Sociedad Argentina de Fisiología Vegetal; 2023

Sociedad Argentina de Fisiología Vegetal

Abiotic stress is the main factor negatively affectingcrop growth and productivity worldwide. Tomato plants are sensitive to variousabiotic stresses. Both alkaline and saline conditions influence photosynthesisand metabolism, and many studies show that tolerance is closely associated withthe ability to maintain redox homeostasis. Previous works demonstrated theparticipation of exogenous nitric oxide (NO) increasing tolerance to alkalinestress. The present study was designed to determine the effect of exogenous NOin tomato seedlings to alleviate alkaline stress (sodium bicarbonate - NaHCO3)in roots and leaves. The experiments were conducted with tomato seedlings (Solanum lycopersicum L UCO14 de INTA), and thetreatments included control treatment (Hoagland nutrient solution), alkalinitytreatment (Hoagland nutrient solution plus 5 mM or 15 mM NaHCO3) andNO treatment (Hoagland nutritive solution plus 5 mM GSNO -S-nitrosoglutathione, a NO donor- and 5 mM or 15 mM NaHCO3) which were performedfor 10 days when all physiological indices were evaluated. Compared with thecontrol, it was observed that tomato plants exposed to alkaline stressdecreased height and fresh weight of shoot and roots and decreasedphotosynthesis and chlorophyll in leaves, while GSNO application toalkaline-stressed seedlings significantly improved these growth parameters. Differentpatterns in ROS production, antioxidant content, lipid peroxidation and organicacid content were observed between roots and leaves of seedlings during NOtreatment under alkaline stress, suggesting a tissue-specific NO responsesalleviating alkaline stress in tomato plants. Analysis of NADH/NAD+content and the expression of genes encoding for the enzyme malatedehydrogenase isoforms and the expression of NAD+ transporter genes(NDT1/2 and PXN), in roots and leaves of tomato plants are in progress and willprovide more information on the redox interaction of tomato plants underalkaline stress.