水稻穗大小决定基因PS1的遗传分析及克隆

Genetic Analysis and Mapping of PS1 Gene Which May Determine Panicle Size in Rice

穗大小是影响水稻产量的重要农艺性状之一。本研究在水稻粳稻品种"中花11号"T-DNA插入突变体库中鉴定了一个植株略矮、穗长变短25%、一次枝梗和二次枝梗数目分别减少33%和80%、且粒型变异的突变体。T-DNA标签共分离检测表明:该突变体的表型与T-DNA插入无关。通过与籼稻品种"珍汕97"配置杂交组合构建遗传作图群体,F2杂合后代符合经典孟德尔遗传分离比3:1,证明突变性状受一对隐性基因PS1(Panicle Size 1)所控制。采用图位克隆的方法,将基因PS1初步定位在第11号染色体短臂上的IN44和IN50标记之间,两标记物理图距为105 kb。对候选基因进行进一步的表达量分析、比较扩增及测序发现基因LOC_Os11g12740(即SP1)可能是本研究的PS1基因。本研究为进一步分离克隆PS1基因及对水稻穗大小发育的深入研究提供依据。

Panicle size is an important agronomic trait which affects rice yield. In this research, we identified a mutant from our T-DNA insertion mutant library of the japonica rice varity, Zhonghual 1. The mutant exhibited a dwarf appearance, and deviant seed size with about 25% shortened panicle length, and 33% and 80% reduced primary and secondary branch number respectively. Co-segregation analysis of T-DNA tag with mutant phenotype confirmed that the mutant phenotypes were not due to T-DNA insertion in the genome. F2 mapping populations were generated by hybridizing homozygous mutant and indica rice varity Zhenshan97. The segregation ratio of wild-type and mutants obey 3：1 Mendel ratio, indicated that the mutant traits were controlled by a single recessive gene, Panicle Size 1 （PSI）. Genetic mapping result indicated that PSI was located between molecular markers IN44 and IN50 on the short arm of chromosome 11 within physical distance of about 105 kb. The results of gene expression level and compared sequencing data suggested that LOC_Osl lg12740 （SP1） might be the candidate gene of PS1 in this study. This study will supporting evidence for further cloning ofPS1 gene and in-depth research on rice panicle size.