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Health based quality traits in tomato

Final Activity Report Summary - QUALITOM (Health based quality traits in tomato)

The consumption of fruits and vegetables rich in health-promoting phytochemicals has been associated with the reduced incidence of age-related chronic disease states. Carotenoids, phenolicss, flavonoids, tocopherols (vitE) and vitamin C are all examples of health-promoting phytochemicals. Tomato fruit (Solanum lycopersicum L.) are one of the principal sources of carotenoids (e.g. lycopene and beta-carotene) in the western diet. These compounds are essential components of the human diet that must be acquired from the diet as they cannot be made in the body. In addition to carotenoid tomato is rich in other nutrients such as the compounds flavonoids and other phenolic compounds. Typical health -promoting compounds have antioxidant properties which means they can dissipate the harmful effects of reactive compounds generated in the body through its metabolic reactions necessary for life.

In this project we have carried out studies to gain insight into the biosynthetic pathways responsible for the formation of health-promoting phytonutrients in tomato and assessed the in vitro antioxidant activity associated with these compounds in the tomato matrix. Additionally, we have carried out in vitro digestion to assess if these health promoting compounds are accessible to the body when present in the plant material that is typically consumed.

A collection of transgenic and natural domesticated tomato plants, as well as wild relatives and introgression lines have been studied. More specifically, the transgenic line containing the bacterial phytoene desaturase (CrtI) gene, leading to higher beta-carotene contents, was studied as compared to the untransformed line, corresponding to the Ailsa Craig variety of the domesticated tomato. In addition, up to 4 red-fruited (2 accessions of S. lycopersicum var. cerasiforme, 1 of S. lycopersicum and 1 of S. pimpinellifolium) and 6 stay-green (3 of S. chilense, 2 of S. peruvianum and 1 of S. chmielewskii) wild relatives of the domesticated tomato and 75 introgression lines (ILs) of Solanum pennellii into the M82 tomato variety, in which each line contained a single introgressed segment from that exotic species were screened.

After evaluating the antioxidant levels (carotenoids, tocopherols and phenolics) of up to 75 introgression lines, five of them have been selected for further studies due to their enhanced carotenoid patterns, which has enabled us to pinpoint definite regions of the tomato genome accounting for them. Concerning the study of the wild relatives of the domesticated tomato, evidence of the complex mechanisms that govern the biosynthesis of antioxidants both across and within taxa have been noticed, which has important repercussions in their in vitro antioxidant potency. Lastly, we are currently processing data relating to the bioaccesibility of carotenoids from the introgression lines surveyed.