Nitric oxide (NO) and its role in post-harvest and the nutraceutical properties of pepper fruits

1 página - Conferencia invitada presentada en Iberian Plant Biology 2023. XVIII Portuguese-Spanish Congress on Plant Biology and the XXV Meeting of the Spanish Society of Plant Biology. 9-12 Julio 2023, Braga, Portugal.Nitric oxide (NO) is a gas radical which is endogenously generated in plant cells with important roles in physiological events such as germination, growth, flowering, senescence, and fruit ripening, but also in the response to biotic and abiotic stresses. In this work, an overview of the main processes modulated by NO in the ripening and post‐harvest of pepper fruits is provided. Pepper (Capsicum annuum L., cv. Melchor) fruits from California type (Syngenta Seeds, Ltd.) were used. NO was found to lower during fruit ripening. In assays where incubation with NO gas was performed, a delay of fruit ripening was observed. This effect was accompanied by an increase in the ascorbate content, as a consequence of the modulation at both gene expression and enzyme activity levels of the L‐galactono‐1,4‐lactone dehydrogenase, the last enzyme of the ascorbate biosynthetic pathway. Overall, it has been demonstrated that much of the effects provoked by NO in pepper fruits are associated to the modulation of the protein functions throughout posttranslational modifications including nitration, S‐ nitrosation, persulfidation, and oxidation. NO also influenced the level of certain flavonoids such as quercetin, a compound which displays anti‐carcinogenic activity. Thus, it was found that crude extracts from pepper fruits showed high anti‐proliferative activity against tumor cell lines from the liver and pancreas. NO was proven to exert important roles in the physiology of pepper fruits. The assays carried out allow to assert that the treatment with NO can be used as a tool to handle post‐harvest strategies focused on the improvement of the nutraceutical properties of pepper fruits and, perhaps, other crops.Supported by European Regional Development Fund‐cofinanced grants from the Ministry of Science and Innovation (PID2019‐103924GB‐I00) and Junta de Andalucía (P18‐FR‐1359), Spai