Two Indica Rice Dwarf Mutant Dwarf Physiological And Molecular Mechanism Research

In this study, the physiological and molecular machanisms of two dwarf mutants, named Tm046and Tm049were investigated based on the relationship between GA/BR and dwarfism with different approaches such as morphology, physiology, biochemistry and gene expression analysis. The main results were as follows:Firstly, the plant height of the two mutants was severly decreased. The internode elongatin pattern of them belonged to dn-type. In contrast to wild type9311, the seed width and tiller number of Tm046was decreased and increased respectively, and the seed length and tiller number of Tm049were both significantly decreased, the seed width of Tm049was increased. The dwarfism of the two mutants was attributed to both cell division and cell expansion. In addition, Tm049shows erection leaves, which is a BR associated phenotype.Secondly, Tm046showed hypersensitive to exgenous GA. Tm049was hyposensitive to exgenous GA and hypersensitive to exgenous BR.Thirdly, the endogenous GA content of Tm046and Tm049was both significantly decreased, especially for Tm046.Finally, according to Tm046, the expression of GA20ox2and GID1was decreased and increased respectively, compared to that of9311. There was no significant difference in the expression of SLR1and RGA1between Tm046and wild type. The GA biosynthesis pathway of Tm046was blocked. In Tm049, the expression of GA20ox2and RGAl was decreased and that of SLR1was increased. The expression of GID1was the same as wild-type. The GA biosynthesis and signaling pathway of Tm049both were abnormal.In conclusion, the imparement of GA biosynthesis resulted in the dwarf of Tm046. The number of tillers of Tm046is high and there was no abnormal phenotyes. There was close relationship between BR and GA in Tm049plant. Consequently, Tm046and Tm049could be used as good materials for dwarf rice breeding and for elucidating the interaction between GA and BR signaling, respectively.