Manipulation of lipophilic antioxidants to enhance oxidative stress tolerance and nutritional quality in transgenic sweetpotato

Abstract

Overproduction of reactive oxygen species (ROS) in plant cells under environmental stress cause oxidative stress, which is one of major factors limiting the plant productivity. To prevent this limitation by stress conditions, a possible strategy is to strengthen the antioxidant defense of plants by gene manipulation of antioxidant enzymes and low molecular-weight (LMW) antioxidants. LMW antioxidants are important for the plant protection to environmental stress and also have nutritional merits for humans as antiaging and antidisease molecules. Sweetpotato [Ipomoea batatas (L.) Lam] as a nutritional food crop has many advantages in terms of the cultivation on the global marginal lands. Thus sweetpotato is considered as an emerging multifunctional food crop ensuring the food and nutrition security in the face of climate crisis, since it contains high levels of LMW antioxidants, minerals, and dietary fiber. This review describes the current status and prospects of metabolic engineering of two lipophilic antioxidants, carotenoids and tocopherols, in transgenic sweetpotato. In addition, the potentiality of an orange (Or) gene involved in enhanced tolerance to various abiotic stresses by high accumulation of carotenoids is introduced in detail. The rational metabolic engineering of LMW antioxidants can be applicable to all plant species to cope with oxidative stress in face of climate change and nutritional problems in aging society.