Rice Genetics and Genomics Information as the Ultimate Tool for Rice Improvement

Abstract

With the completion of the genome sequence, rice has become a very valuable crop not only in agriculture but also in basic and applied research. Accompanying this historical achievement, fundamental knowledge on the biology of the rice plant has been elucidated and various strategies have been developed to further clarify the molecular basis of its growth and development. These include microarray of DNA sequences representing genic and/or intergenic information for inheritance, non-coding RNA identification regulating gene expression, and proteome information including interaction required for hormonal signal transduction. The availability of an accurate, complete, map-based sequence provides a real opportunity to identify all the genes corresponding to phenotypes and thereby promote ground breaking research using conventional genetic tools. This is clearly shown by the increase in the number of rice genes controlling phenotypes that have been identified so far based on genomics information. Useful applications in physiological studies ha, e also led to the clarification of gibberellin signal transduction pathway or discovery of novel genes involved in flowering among others. Another important point for basic research that will greatly facilitated by the standard genome sequence information of Oryza sativa is the clarification of biological diversity among the different species in the genus Oryza. Comparative analysis of the two major subspecies of cultivated rice, indica and japonica, and that of relative wild species will not only clarify the evolution of rice but will also facilitate the discovery of genetically important SNPs related to linkage disequilibrium. These basic tools and knowledge will provide a great opportunity to transfer the highly desirable alleles to actual breeding programs for improvement of current rice cultivars to feed the still increasing world population.