[Isolation and characterization of the centromeric BAC clones from different genomes in genus Oryza]

Centromeres play an important role in ensuring the correct segregation and transmission of chromosome during mitosis and meiosis in eukaryotes. In this research, we constructed five BAC libraries for diploid wild rice with different genomes. Together with the technique of colony blot hybridization and fluorescence in situ hybridization (FISH), centromere-related BAC clones were screened and characterized from different genomes. Meanwhile, co-hybridization was detected between these clones and the five genomes. The results from this study demonstrated that: (1) there were centromere-specific satellite repeat in Oryza officinalis (CC genome) and O. brachyantha (FF genome), respectively, and centromere-specific CRR-related sequence was found in O. brachyantha; (2) homology sequences of CentO and CRR of O. sativa (AA genome) were detected on all centromeres of O. glaberrima (AA genome), O. punctata (BB genome) and O. australiensis (EE genome); And (3) the two somatic chromosomes of O. officinalis comprised of homology sequences of CentO satellites as revealed FISH analysis probed with RCS2. Homology sequences of CRR of O. sativa were also detected on all centromeres of O. officinalis. The results provided a foundation toward cloning the centromeric sequences from different genomes of genus Oryza, studying centromere organization and evolution of different genome, analyzing the relationship between centromeric structure and function among different genome.