Functional Analysis Of The Meiotic Gene OsSGO1 In Oryza Sativa

Meiosis, an essential process in sexual life cycle, is necessary not only for the maintenance of genomic stability but also for the creation of genetic diversity. Meiosis involves two sequential rounds of chromosome segregation following a single round of DNA replication. The first meiotic division is unique and involves the segregation of homologous chromosomes. To ensure accurate segregation, homologous chromosomes form stable bivalents through a complex processes which include homologous pairing, synapsis and recombination. The corn Sgo1 gene has been shown to play an important role in protecting of centromeric cohesion. OsSGO1 is the rice homologue of the maize Sgo1 gene. Here, we analyzed the function of OsSGO1 in meiosis using the RNA interference (RNAi) approach. We constructed an OsSGO1-RNAi vector and transformed it into rice calli by Agrobacterium-mediated DNA transfer. OsSGO1-RNAi lines were obtained by screening the plants regenerated from the transformed calli by PCR. The OsSGO1-RNAi lines showed normal vegetative growth but sterile during flowering phase. The sterility phenotypes were associated with down-regulated OsSGO1 transcript level mediated by RNAi. Further cytological observations of male meiocytes revealed that knockdown of OsSGO1 caused precocious disassociation and random segregation of sister chromatids at telophaseâ… and anaphase II, respectively, which finally led to sterile pollen formation. Immunostaining experiments revealed that the OsSGO1 localizes to centromere. These results indicate that OsSGO1 is essential for rice meiosis and plays an important role in protecting centromeric cohesion during meiosis.