水稻粒宽QTL-GW(t)的克隆与功能分析

The grain shape, consisting of grain length, grain width and a length/width ratio, is the determinant of grain yield and apperence qualities in rice. Characterization and identification of novel genes for grain shape can help facilitate the understanding of grain formation and genetic mechanism, and improvement of grain yield and quality by marker-assisted selection in rice breeding program. In the study, a japonica cultivar NIP (wide grain) and an indica cultivar ROS (narrow grain) were the parental lines. Compared with the NIP, the grain width was reduced 1.3 mm, the length/width ratio was increased 1.5 and 1000-grain weights were decreased about 10 g in ROS. Based on F2, F3, BC2F2 and BC2F3 populations, the QTL-Grain Width (t) (qGW(t)) gene was preliminarily mapped between the markers SH61 and SH28 on chromosome 12, an approximate 1 cM region. So far, no gene that was involved in the development of grain was reported in this region. Based on this, we will further construct BC3F2, BC3F3, BC4F2 and BC4F3 populations to perform fine mapping and gene cloning. After that, we will employ DNA complementation test, RNAi, expression analysis, subcellular localization, histocytological analysis to understand of the molecular mechanism involved in grain shape development in rice and identify the value in breeding field.

粒型（包括粒长、粒宽和长宽比）是水稻产量和外观品质的重要指标，发掘和深入研究水稻粒型基因对解析粒型表型构成、遗传机制和分子标记辅助选择育种具有重要的理论和实践意义。本研究利用粳稻品种日本晴NIP(宽粒)和籼稻品种ROS(窄粒)作为亲本材料。与日本晴NIP相比，ROS粒宽减小1.3mm，长宽比增加约1.5，千粒重下降约10g。利用F2、F3、BC2F2和BC2F3遗传群体，将粒宽QTL-Grain Width (t) (qGW(t))定位在第12号染色体的标记SH61与SH28之间，约1cM的区间内。目前，定位区间内并未发现已克隆的粒型相关基因被报道，该基因可能是新的功能基因。在此基础上，本申请项目拟构建高世代回交群体进行精细定位、克隆基因并通过DNA互补、RNAi、表达模式分析、亚细胞定位、细胞组织学等分析了解qGW(t)基因调控粒型的分子机理，同时挖掘其在育种领域中的价值。

粒型（包括粒长、粒宽和长宽比）是水稻产量和外观品质的重要指标，发掘和深入研究水稻粒.型基因对解析粒型表型构成、遗传机制和分子标记辅助选择育种具有重要的理论和实践意义。.本研究利用粳稻品种日本晴NIP(宽粒)和籼稻品种ROS(窄粒)作为亲本材料。与日本晴NIP相比.，ROS粒宽减小1.3mm，长宽比增加约1.5，千粒重下降约10g。利用F2、F3、BC2F2和BC2F3遗传.群体，将粒宽QTL-Grain Width (t) (qGW(t))定位在第12号染色体的标记SH61与SH28之间，约.1cM的区间内。目前，定位区间内并未发现已克隆的粒型相关基因被报道，该基因可能是新的.功能基因。本申请项目构建高世代回交群体进行精细定位、克隆基因并通过DN.A互补、RNAi、表达模式分析、亚细胞定位、细胞组织学等分析了解qGW(t)基因调控粒型的分.子机理，同时挖掘其在育种领域中的价值。

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