| Flowering is an important stage in life cycle of plants, which indicates the transitionfrom the vegetable phase to reproductive phase. Rice (Oryza sativa L.),a short-day plant, isone of the most important crops in the world. The flowering time is linked to cropproductivity. With the completion of rice genome sequencing and establishment of a largenumber of rice mutant libraries, many genes related to heading time were successfully cloned.The following functional analysis contribute to establish the molecular basis of regulatorynetwork and provide important genetic basis and theoretical guidance for the breeding.The target of this article is an early flowering mutant osef1which was selected from theone million mutant library of our laboratory. This work is based on the following results:According to the flanking sequence amplification result and complementation test, we provedthat the osef1phenotype was resulted from Tos17insertion at3’UTR in OsEF1gene.Subcellular localization revealed that OsEF1gene was localized in the nucleus in onionepidermal cells. We used yeast two-hybrid test to acquire thirty-five candidate proteins whichinteracted with OsEF1protein.Firstly, the field survey of agronomic traits found that the flowering time of Osef1mutant is30days earlier than the wild-type in the natural long-day conditions. Also, themutant’s height is about17centimeters shorter.Secondly, The OsEF1protein expression level in osef1mutant tested by the antibody ofOsEF1revealed that the translation of OsEF1is decreased as the Tos17insertion at3’UTR inOsEF1gene.Thirdly, the diurnal expression pattern of OsEF1were analyzed under long-daycondition by quantitative RT-PCR. We found that OsEF1mRNA accumulate during darkperiod, with a peak at the beginning of the light. The results suggest that OsEF1transcriptionexhibites a diurnal rhythm expression pattern under LD conditions. Comparison of theexpression level of some flowering related genes revealed that OsEF1regulates theexpression of Hd1.Fourthly, BiFC assay confirmed that OsEF1interacts with OSK4, which was screenedby yeast two-hybrid system. In order to analyse whether the OsK4gene is involved in theregulation of flowering time, RNAi method was used to inference the expression of the OsK4gene using the pTCK309vector to construct the RNAi vector. Then there were three lineswith early flowering phenotype in the transgenic groups. |
