Antioxidant metabolites in tomato organs as response to virus infection

The study regards the effects of eggplant mottled dwarf virus (EMDV) on Campanian tomato ecotypes Tondo Giallo, characterized by long shelf life, and Maiese, on ascorbic acid and polyphenol accumulations as plant response to the infection stress. Such response to virus is little studied, thus, we explored this on ecotypes for which we already found a different pattern of the metabolite accumulations during ripening that we associated also to their different shelf life. The EMDV was mechanically inoculated onto tomato plants grown in greenhouse until the second leaf stage, and virus infection was monitored by symptom expression and ELISA test. Both ecotypes showed almost similar susceptibility to the infection. In post inoculation, for both ecotypes total ascorbic acid (ascorbic and dehydroascorbic acids, tAsA) increased in leaves of diseased plants respect to healthy plants, in these latters higher tAsA was recorded for Maiese than for Tondo Giallo. Also, in leaves, although healthy Maiese showed lower total polyphenols (tPph) than healthy Tondo Giallo, in the diseased ecotypes the relative contents were inverted because tPph contents increased in Maiese and decreased in Tondo Giallo respect to the levels in the respective healthy plants. Both ecotypes, transferred in field, showed higher tPph in the typical discoloured symptomatic fruits, than in those from healty plants at any stage of sampling: immature, mature green, turning and ripe. Instead, tAsA in diseased fruits was generally lower for Tondo Giallo, and at turning and at ripe higher for Maiese, than in fruits from the respective healthy plants. Although both ecotypes were susceptible to EMDV infection, the host response seems to depend by the genotype, since Tondo Giallo did not always show increase in the antioxidant metabolites in the diseased organs as expected, because virus usually upregulates response genes. Investigations on gene regulations in tomatoes by EMDV have to be carried out

Antioxidant accumulation in different pepper organs

Pepper (Capsicum annuum L.) is an important crop not only for the economic point of view, but also for the nutritional value of its fruits which are a source of antioxidants such as ascorbic acid, polyphenols, carotenoids, and chlorophylls. These, reduce the risk of onset of diseases such as atherosclerosis, some cancers and degenerative and cardiovascular disease. Antioxidants vary according to the genotype, developmental stage and environmental conditions. The aim of this study is to evaluate during ripening the accumulation of antioxidant metabolites in different pepper ecotypes and varieties which differ in the fruit colour and shape. Pepper seeds were provided by SemiOrto Sementi (http://www.semiorto.com) and plant germoplasm Regione Campania. The experiments were carried out in a greenhouse. Antioxidants in leaves were evaluated at vegetative stage, and in fruits at the stages: immature (IG); mature green (MG); turning (T), and ripe (R). In leaves, all analyzed antioxidants varied according to the genotypes. In general at higher polyphenol contents corresponded lower total ascorbic acid. Among the numerous genotypes, Corno di Capra Giallo showed the highest accumulations of total ascorbic acid, licopene, ß‐carotene and flavonoids and had also a good amount of total polyphenols and chlorophylls. In fruits, generally total ascorbic acid increased along ripening, and at the ripe the highest values was reached in Puparulillo and Papecchia and the lowest in Nocera Giallo. Instead, in the ecotype Rogianiello the highest total ascorbic acid was at MG stage. Polyphenols generally showed a minimum at MG and in the other stages was variable among ecotypes. This investigation could be useful as preliminary study for the pepper resistance to abiotic and biotic stresses, that are know to be controlled by antioxidants, and to evaluate nutraceutical quality of peppers that in Mediterranean diet are consumed at any ripening stage