Fine Mapping And Functional Analysis Of The Rice Gene Mutant37

MicroRNA is the small RNA molecule found in recent years, it’s short, single, and the target gene has the characteristic of the post-transcriptional regulation. There are two precursors to synthesize microRNA:one is a kind of endogenous DNA templates, and the other is pre-mRNA. The synthesis pathway of microRNA is different between plants and animals. Plant using Dicer-likel (DL1) as the restriction enzyme twice where is completed within the nucleus. With the help of HST, miRNA/miRNA* completes subsequent assembly in the cytoplasm. MicroRNA has two synthetic pathways, so its species are also various. Besides, it plays a very important role in biological growth and development; responsing to biotic and abiotic stresses and regulating agronomic traits. As a food crop, rice is a model plant of endogen (Oryza Sativa L.) and discovers its mechanism of growth and development can effectively solve the food problem. In our study, ZH11 was mutagenized with EMS, and mutant37 showed more tillers, dwarf stem was obtained. Related morphological observation, genetic analysis, gene location, and preliminary analysis of function were carried on. Research results are as follow:1. After comparative analysis of phenotypes, we found that leaves were narrower and internodes were shorter in mutant37. By morphological observation, the cells of leaf sheath were found similar among mutant, intermediate type and wild type. The possible reason to explain the dwarf phenotype of mutant is the decrease of cell number.2. Genetic analysis result showed that the mutant traits were regulated by a dominant nuclear gene. Then we localized the gene in 89 kb physical distance in short arm of chromosome 2 using map-based cloning.3. Four candidate genes(Os02g0180500、Os02g0180700、Os02g0180800、 Os02g0180900)were identified by sequencing. There was no base mutation, deletion or insertion. We suspected that miRl 56d(Os02g0180800) might be one of the reasons for the mutation which was involved in epigenetic regulation according to the functional research of miR156d from other researcher.4. We constructed the overexpression and the RNA interference vectors of miR156d, and introduced them into mutant plants by Agrobacterium tumefaciens-mediated transformation for genetic complementation. The transformants were immigrated to the field of rice research institute in Hainan.