OsMADS6 Interacts With OsMADS32, REP1 In Specifying Palea Identity And Development

Rice is not only as one of the world’s most important food crops, but also is one of monocots model plants The development of rice flower organs (reproductive organs) has a crucial decision to rice yield. During floral organ development, it is just the crucial period of increasing agricultural production.The outer wheel organs (lemma and pale) of rice are responsible for protecting the florets and kernels from pathogen and insect attack besides supplying carbohydrates to developing seeds.Therefor, it’s theoretically important and practical to study the molecular mechanism of flower development.Through the method of forward and reverse genetics, several very important genes in specifying rice palea identity and morphogenesis have been reported. But we still have little known about the molecular mechanism of identity and morphogenesis of the lemma and palea. Our lab has obtained three genes controlling palea development by the method of forward genetics.Such as a TCP family gene RETARDED PALEA1 (REP1), and two MADS-box genes (OsMADS6 and OsMADS32). But it is remain unclear that how to control palea identity development and morphogenes is among the three genes in molecular mechanism. Therefore, with osmads6, osmads32 and rep1 three mutants as research materials, we researched how interaction among OsMADS6, OsMADS32, REP1 to regulate rice palea development in the thesis by genetics and molecular biology research.1. Through observed osmads6/osmads32, osmads6/repl double mutant and osmads6/osmads32/rep1 triple mutants, it showed that no matter in single mutant and double mutants or triple mutants, the identity of palea was changed. The numbers of vascular bundle and the mtp structure identity of palea were similar to osmads6 single mutants. It suggested OsMADS6 was up-stream gene of OsMADS32 and REP1. It showed that OsMADS6 had a more important role in specifying palea identity and development.2. OsMADS6, OsMADS32 and REP1 had different regulation mechanism in identity and morphogenesis of palea. In the identity of palea stage. OsMADS32 could inhibit OsMADS6; OsMADS6 probably promoted the expression of REP1; OsMADS32 could promote the expression of REP1. In palea morphogenesis development stage,OsMADS6 could inhibit OsMADS32 expression, at the same time promoted REP1 expression to regulate palea late formation; OsMADS32 promoted OsMADS6 and REP1 expression; REP1 inhibited OsMADS6 expression.3. Through double yeast hybridization experiments, we detected that OsMADS6 could interact with OsMADS32 and REP1 in protein level, but OsMADS32 was not detected protein interactions with REPl. It Suggested that OsMADS6, OsMADS32 and REP1 can form protein complexes to regulate palea development.