Gene Cloning And Function Al Analysis Of A Flower Develop Ment Mutant In Rice

Rice is the model for studying development of monocotyledon in Molecular Biology and mutants are important materials for research into functional genomics. The acquisition and research on the mutants related to development play an important role in understanding the function and interaction of genes in development process, especially in floral development. Recently, there have been many progresses in genes regulating the development of rice. Many genes about this process have been cloned by mutants. So that, the study on molecular mechanism of monocotyledon development using rice mutants becomes one of the focuses in plant molecular genetics. The research about development regulation and control mechanism has a major significance in higher plantWe obtained a floral organ mutant from the Nipponbare mutant library which was constructed by our lab. Further observation of the whole plant found that there were differences from height, leaf, and sheath, particularly in floral organ. Genetic analysis showed the phenotype of the mutant is controlled by a semi-dominant gene on Chromosome8. We fine mapped this gene and predicted it as a WD40repeat protein which is homologous with TOPLESS in Arabidopsis thaliana by map-based cloning and we provisionally named it as Ostopless8(Ostpl8). The sequencing result showed that the A change to T and cause GAG change to GTG (Glu> Val). We constructed several vectors such as complementation, GUS, GFP and over-expression to research the gene’s function. The mutation in Nipponbare successfully caused mutant phenotype and GUS transgene plant showed the expression location iof Ostpl8in tissue while other vectors were under transgene. We extract RNA from leaves of wild type, mutant and heterozygote in vegetative period for gene chip and found some relationship between genes, some of these results had been proved by Realtime-PCR. The cloning and function analysis of Ostpl8lays a good foundation for further studying of molecular mechanisms in regulation of rice development.