ABSTRACT
Genetic engineering gives plants additional characteristics and values for cultivation, post-harvest products and their quality, in addition to quantitatively improved yield. Genetically modifi ed (GM) plants of the “first generation” were conferred with traits beneficial to producers, whereas GM plants in subsequent “generations” are intended to provide benefi cial traits for consumers. Golden Rice developed by Professor Ingo Potrykus is a promising example of a GM plant in the second generation, and has overcome a number of obstacles for practical use. Furthermore, consumer-acceptable plants with health-promoting properties that are genetically modifi ed using native genes are being developed. The emerging technology of metabolomics will also support the commercial realization of GM plants providing healthy biochemical components, highly functional in providing human health. Another example of rice producing health benefi t is that provided by rice seed-based edible vaccines expressing T-cells epitope peptides derived from Japanese cedar major pollen allergens, which have been used to successfully suppress allergen-specifi c Th2-mediated immunoglobulin E (IgE) responses in mouse experiments. In order to further expand the application of seed-based allergen-specifi c immunotherapy for controlling Japanese cedar pollinosis, Yang et al. (2007) generated transgenic
rice plants that specifi cally express recombinant Cry j1 allergens in seeds. Cyry j1 allergens give low specifi c IgE-binding activity but contain all of the T-cell epitopes. The allergens were expressed directly or as a protein fusion with the major rice storage protein glutelin. Fusion proteins expressed under control of the strong rice endosperm-specifi c GluB-1 promoter accumulated in rice endosperm tissue up to 15% of the total seed protein. The fusion proteins aggregated with cysteine-rich prolamin and were deposited in endoplasmic reticulum-derived protein body I. The production of transgenic rice expressing structurally disrupted Cry j1 peptides with low IgE binding activity but spanning the entire Cry j1 region can be used as an universal, safe and effective tolerogen for rice seed-based oral immunotherapy for cedar pollen allergy in humans and other mammals.
