株型是产量建成的形态学基础，株型改良及相关基因的分子鉴定和利用将有利于设计育种。本申请以一个从日本晴的EMS诱变库中获得的多蘖矮秆迟抽穗的突变体tr1（tree-like on chromosome 1）为研究材料，在已精细定位并确定候选基因（植物特有的MSH7增变基因）的研究基础上，拟进一步利用TR1等位突变体、完成细胞形态观察，分离和验证该株型控制基因；同时构建不同的功能和表达载体及Cas9突变体，开展tr1的功能研究；结合RNA-seq和酵母双杂交分析，开展上下游基因和互作蛋白的筛选、验证和分析，初步探明TR1(OsMSH7)基因如何高转录表达形成增变表型及株型发育遗传和调控机理；以及利用OsMSH7具有增变表型创制水稻突变体；本研究为丰富水稻株型的基因资源和种质资源，开展分子设计育种，培育新株型高产水稻新品种打下了良好的理论和材料基础

Plant architecture is the morphological basis of yield formation. Plant architecture improvement, and molecular identification and utilization of its related genes will be helpful to design breeding. In this study, the semi dominant mutant with multi tillers dwarfing late heading phenotype tr1 (tree-like on chromosome 1) was obtained from mutant library of the Nipponbare after EMS mutagenesis. On the base of fine mapping and identifying candidate gene, we will carry out the cell morphology observation, isolation and cloning of the plant architecture gene; TR1 gene function analysis by constructing different function and expression vectors and Cas9 mutant analyzing; and RNA-seq and yeast two-hybrid system to screening, verifying and analyzing of upstream and downstream genes and interacting proteins of TR1 using tr1 allelic mutants. This research will preliminarily ascertain the genetic and molecular mechanism of the TR1 (OsMSH7) gene in plant architecture development,and its mutator phenotype mechanism, and creat rice mutants using OsMSH7 mutator phenotype method. It will enrich rice plant-architecture germplasm, and benefit our understanding of the gene regulatory networks, provide theoretical and materials basis of molecular design breeding for high yield with new plant-type in rice.