Vegetable oil production in vegetative plant tissues

Abstract

Vegetable oils, which are stored in seeds as triacylglycerol (TAG), represent a valuable source of food, fuel, and industrial raw materials. Given the increasing demand for vegetable oils, it is essential to increase vegetable oil production in a sustainable manner. To boost the supply of vegetable oil, strategies to produce oils in the vegetative tissues of biomass crops are being investigated. Producing oils in leaves is challenging, due to the major role of leaves in producing sugars, via photosynthesis, that are then transported to storage tissues. Several strategies have been developed to overcome this limitation, such as increasing fatty acid and TAG biosynthesis, stabilizing lipid droplets, and reducing carbon flux to starch biosynthesis in the leaves. For example, overexpressing the WRINKLED 1 (WRI1) transcription factor, which upregulates fatty acid biosynthesis; DIACYLGLYCEROL ACYLTRANSFERASE 1 (DGAT1) enzymes, which participate in the last step of TAG biosynthesis; and oleosin, which stabilizes oil droplets and simultaneously suppressing the expression of genes encoding enzymes involved in lipogenesis and lipases led to the accumulation of significant levels of oil in leaves in tobacco, Arabidopsis, and sugarcane. To facilitate the sustainable production of biofuels and industrial raw materials, efforts are underway to modulate metabolic flux between the carbohydrate and lipid biosynthesis pathways in non-edible biomass plants that can grow on barren or reclaimed lands.