Download Resveratrol, a plant phenolic compound, is found in grapes and red

BIOTECHNOLOGICAL PRODUCTION OF RESVERATROL IN TOMATO IMPROVES THE
HEALTH PROPERTIES OF FRUITS AND AFFECTS THE SEEDS SET
Laddomada B., Ingrosso I., Di Presa C.A., D’Amico L., Santino A., Giovinazzo G.
Istituto di Scienze delle Produzioni Alimentari-C.N.R, Via Monteroni, 73100 Lecce, Italy
Resveratrol, a plant phenolic compound, is found in grapes and red wine but is not widely
distributed in other common food sources. The pathway for resveratrol biosynthesis is well
characterised. In this work metabolic engineering of resveratrol has been achieved in tomato plants
(Lycopersicon esculentum Mill.). Tomato plants synthesising resveratrol were obtained via the
heterologous expression of a grape (Vitis vinifera L.) cDNA encoding for the enzyme stilbene
synthase (StSy), under the control of the cauliflower mosaic virus (CaMV) 35S promoter.
Transgenic plants accumulated novel compounds identified by high-pressure liquid
chromatography, as trans-resveratrol and trans-resveratrol-glucopyranoside. The amount of transresveratrol and its piceid form was evaluated in different tissues of the transgenic plants. It was
found that the content of the metabolite varied during fruit maturation by up to 53 g g-1 fresh
weight of the total trans-resveratrol at the red stage of ripening. This metabolite accumulation was
possibly dependent upon a combination of sufficiently high levels of stilbene synthase and the
availability of substrates. To establish whether the presence of a novel antioxidant molecule
affected the redox regulation in transgenic tomato fruit cells, the effect of resveratrol accumulation
on the naturally present antioxidant pool was analysed.
We show here that in transgenic fruits which accumulate trans-resveratrol there is an increase in the
levels of ascorbate and glutathione, the soluble antioxidants of primary metabolism, as well as in
the total antioxidant activity. These results could explain the higher capability of transgenic fruits to
counteract the pro-inflammatory effects of phorbol ester in monocyte-macrophages, via the
inhibition of induced cyclooxygenase-2 enzyme.
Moreover stsy overexpression caused altered pollen formation and male sterility, probably due to
competition between the introduced StSy enzyme and the endogenous Chalcone Synthase for the
common substrates. Thus, StSy gene expression in tomato can be promising strategy for the
production of parthenocarpic fruits and the development of a novel hybrid seed system.