Seminars

A very large effort has been made in rice functional genomics research involving many institutions and multiple funding agencies in China with the long-term goal to identify the functions of all the genes in the rice genome together with joint efforts by the international community. Significant progress has been made in recent years in the following areas: (1) development of technological platforms, (2) functional genomics of agriculturally important traits and, (3) molecular cloning of functional genes. The platforms aims at enabling high throughput analyses and effective characterization of gene functions, which consist of three major parts: generation and characterization of a large mutant library by T-DNA insertion; global expression profiling of genes in the entire genome; and isolation of full length cDNAs of indica rice. The traits targeted for functional genomic studies in this program include grain quality, yield, stress tolerance, disease and insect resistance, and nutrient use efficiency. Totally 270,000 independent transformants have been generated for the T-DNA insertion mutant library and are now being screened for mutations affecting an array of traits. Over 50000 flanking sequences have been isolated, and their analyses identified a number of interesting features of nonrandom distributions of the T-DNA insertions in the rice genome. A large number of mutants have now been targeted for gene isolation. For genome-wide expression profiling, data have been collected from more than 40 tissues covering the whole life cycle of the rice plants and under various conditions. Map-based cloning has been applied to isolate genes of agronomic importance. Dozens of genes have been cloned using this approach including genes for yield traits, grain quality, fertility restoration, disease resistance and salt tolerance. Attempts have also been made to incorporate these genes into rice breeding programs.