Exploring Estrategies for Vitamin E Biofortification in Green Leaves


García Romañach, Laura


Tocopherols and tocotrienols are antioxidant compounds that form the vitamin E family. Their synthesis occurs in plastids and they are regulated during plant development and oxidative stress. The function of vitamin E in photosynthetic organisms is to contribute to their photoprotection, inhibiting singlet oxygen and lipid peroxidation. In addition, this vitamin also has an important influence on human health, preventing diseases related to oxidative stress. Increasing the content of α-tocopherol, the tocopherol with the highest antioxidant activity in vivo, is the main objective of biofortification in vitamin E. In this study, different approaches based on metabolic engineering of the enzymes that catalyze the synthesis of tocopherols. As a basis for this work, a system developed in the host laboratory has been used that allows the artificial differentiation of chloroplasts to Chromoplasts in Nicotiana benthamiana leaves. It has been proven that the differentiation of synthetic chromoplasts favors the synthesis and accumulation of α-tocopherol, due to an increase in plasma clumps. Additional channeling of metabolic precursors into tocopherol synthesis by overexpression of VTE1 increases the concentration of α-tocopherol but also γ-tocopherol, suggesting limiting activity of VTE4 (which transforms γ-tocopherol into α-tocopherol). Finally, it has been verified that the exposure of N. benthamiana leaves to high intensity light also produces a change in the composition of tocopherols, increasing the proportion of α-tocopherol. Therefore, these results provide solutions for the biofortification of plants in vitamin E.



Leivar Rico, Pau 


IQS SE - Undergraduate Program in Biotechnology