Study Of Functions Of MiRNA160 And MiRNA167 In Rice Architecture

miRNAs are endogenous, about 21-nucliotide, non-coding riboregulators that regulate many developmentally important transcription factor genes. In this study, we investigate the functions of miR160b and miR167a in rice architecture by bioinformatics prediction, gene expressing examination and paraffin section, using MIR160b and MIR167a overexpressing TO single copy plants as the materials. The detail results in this study are summarized as follows:1 The genotypes of 30 T1 miRNAs overexpressing plants are identified by PCR. There are 22 positive plants and 9 negative ones. The segregation ratio is about 3:1 as expected. All the positive plants show the mutant phenotypes while the negative are as normal as the ordinary plants. This result demonstrates the cosegregation between the genotypes and the phenotypes on DNA level.2 The expressing levels of miR160a and miR167b are tested in overexpressing plants using miRNA stem-loop RT-PCR. The result, increasing expressing levels of these two miRNAs, shows that the overexpressing vectors worked well in the plants. Furthermore, all of the identified overexpressing plants show the mutant phenotypes so the phenotypes and the expressing level of miR160b and miR167a are cosegregated.3 The phenotypes of the miRNAs overexpressing plants are analyzed carefully. In MIR160b overexpressing plants, the tiller angle increases 1.2 times and seeds setting rate decreases 85.3%. In MIR167a overexpressing plants, the tiller angle increases 0.8 times, the height decreases 35.7%, the effective tiller numbers decreases 44.9% and the seeds setting rate decreases 79.6%.4 ARF13 and ARF12 are identified as the target genes of miR160b and miR167a respectively in rice by bioinformatics prediction and gene expressing level analysis. The expressing levels of these two genes are inversely correlated with the miRNAs. 5 The expressing levels of 7 genes related with auxin, GH3.1, GH3.3, GH3.4, GH3.8, IAA21, LAZY1 and PIN1, are tested by RT-PCR and real-time PCR. These 7 genes are included in the miRNA regulation network in plant architecture because the expressing levels change in various degrees.