COMPASS-like Complex Regulates Vegetative To Flower Transition In Oryza Sativa

Flowering is the transition process from vegetative phase to reproductive growth of plants, which is regulated by both external environment and internal genetic factors.This process is critical for the reproduction of plants themselves, as well as human beings. As one of the most important crops, rice raising one-thirds of word's population. The flowering time of rice influence not only rice yield but also food safety, which has important theoretical significance and practical value.In this study, we start from rice COMPASS-like complex, through genetics,biochemistry and molecular biology methods, reveals that the epigenetics modification by the complex has apparent regulation in rice growth, development and flowering process. the main results are as follws.(1) Rice SDG723 was significantly close to ATX1 from Arabidopsis thaliana.When transformed 35S::SDG723 into atx1 mutant, the phenotype of atx1 was well rescued, which reveals that SDG723 was orthologs of ATX1.(2) The T-DNA insertion mutant of SDG723 showed late flowering phenotype under long day condition. Through RNAi(RNA interference)method,SDG723 was knock down, and the RNAi lines showed the same phenotype as the T-DNA insertion mutant.(3) SDG723 and Os WDR5 a were fusioned with GFP. After transformed into rice, the subcellular localization showed that SDG723 and Os WDR5 a could colocalized into nuclear. While Os WDR5 a was also expressed in the cytoplasm?(4) Pull down showed that Os WDR5 a could specific bind H3 in vitro.(5) In vitro methylation activity study has shown, Os WDR5 a can significantly promote the methyltransferase activity of SDG723.(6) Homozygote of the T-DNA insertion mutants of Os WDR5 a were lethal.And the death occurred in the early post-fertilization processes of grain filling ? When Ubqutin::WDR5a was transformed into oswdr5 T-DNA mutant, the lethal phenotype was rescued?(7) When Os WDR5 awas knock down through RNAi(RNA interference)method, the RNAi lines showed the same phenotype wihth the SDG723 RNAi mutants.(8) Through sampling every four hours in the continuous 24 h,RT-q PCR was used to detect the transcrition level of important flowering pathway genes. The result showed that SDG723 RNAi and WDR5 RNAi lines has the same regulation pattern with these genes. The relative transcription level of EHD1,RTF1 and EHD3 a were greatly reduced?...