Research Of REP1,REPEN1 And OsMADS6 In Regulating Rice Floral Development

Angiosperm is the largest plant species in the world because of the sexual reproduction during evolution. The appearance of flowers ensures that sexual reproduction could be carried out effectively, which is also the reason for the angiosperms are known as flowering plants. While the colorful and diversity flowers provide angiosperms more reproductive opportunities. Among them, the symmetry of flowers is one of the factors that affect the diversity of flowers. Therefore, the studies on flowers symmetry have become a hotspot in evolutionary developmental biology recently. The investigation on mechanism of flower symmetry in Antirrhinum majus has contributed a big deal to our knowledge in dicots. The floral organ development program is conservative in some ways. However, considering that the flower morphology are significantly different between monocots and dicots, there might be some different mechanisms of flower symmetry in monocots. As one of the most important alimentary crops, rice has a small genome and is easy to do gene transform. In addition, its whole genome sequencing was completed. Therefore, as a model monocot, rice is an ideal experimental material. Through genetic screen, we identified the mutants with palea defects. To determine the function and networks of these genes, we studied the phenotypes and expression pattern between the mutants and wild type. The main results are as follow:1. Deletion of REPEN1 causes a defection in palea developmentThe palea of repenl is a mosaic organ with some lemma features. This demonstrates that the palea of repen1 partially transform into lemma-like organ. Deletion of REPEN1 causes a defect in palea since stage sp4. We speculate that REPEN1 regulates development of palea since the initiation of palea primordium.2. Interaction between REPEN1 and REP1There is notable distinction between single mutants and double mutant rep1 repenl. And the expression level of REP1 is slightly higher in repenl. The results indicate that REPEN1 inhibits REP1expression and regulate rice palea development.3. Interaction between REPEN1 and OsMADS6The phenotypes of single mutants are significantly different from double mutant repenl, osmads6 and repen1 osmads6 double mutant. The expression level of OsMADS6 is slightly higher in repenl. Meanwhile, the expression pattern of OSMADS6 in repenl is changed. It shows that OsMADS6 is up-regulated by REPEN1 and regulate rice palea development cooperatively.4. Integrative function of REPEN1, REP1 and OsMADS6 in flower symmetryREPEN1 influences flower symmetry by regulating development of palea. The observation of repl repenland repenl osmads6 double mutants suggests that REPEN1, REP1 and OsMADS6 can influence development of palea and control both number and arrangement of floral organs in addition to regulating the flower symmetry development.