[Improving the nutritional value of plant foods through transgenic approaches].

The most nutrients required in the human diet come from plants. The nutritional quality of plant products affects the human healthy. The advance of molecular cloning and transgenic technology has provided a new way to enhance the nutritional value of plant material. Transgenic modification of plant nutritional value has progressed greatly in the following aspects: improving the quality, composition and levels of protein, starch and fatty acid in different crops; increasing the levels of antioxidants (e.g. carotenoids and flavonoids); breeding the new type of plants with medical value for human. To date, many transgenic plants with nutritional enhancement have been developed. These transgenic plant products could be directly used as human diet or as valued materials in developing the "functional food" with especial nutritional quality and healthy effects after they are approved by a series of evaluations on their safety and nutritional efficiency for human being. We designed new zinc finger transcription factors (ZFP-TFs) that can specifically down-regulate the expression of the endogenous soybean FAD2-1 gene which catalyzes oleic acid to linoleic acid. Seed-specific expression of these ZFP-TFs in transgenic soybean somatic embryos repressed FAD2-1 transcription and increased significantly the levels of oleic acid, indicating that the engineered ZFP-TFs are capable of regulating fatty acid metabolism and modulating the expression of endogenous genes in plants.