RNAi and functional genomics

Various genome projects have recently provided abundant data on the genomes of different organisms, from simple microbes to higher plants and animals. More tools are needed to characterize the function of these many genes. RNAi offers many advantages regarding the down-regulation of gene expression. To increase the effectiveness of RNAi, novel RNAi methods (transient RNAi, differential RNAi (dRNAi), comprehensive RNAi with simple construction, quantitatively regulated RNAi, etc.) have been developed for functional genomics in plant. These methods have been used to reveal the functions of many genes and functional networks in genomes of higher plants. The further development of a gene-substitution method based on dRNAi could provide a new tool for the characterization of plant gene functions using a more rational approach. RNAi has also been shown to be useful in metabolic engineering. Detailed characterization of the mechanism of RNAi could also provide the molecular basis for the next generation of gene engineering.