BACKGROUND Limited genetic resource in the cultivated rice may hinder further yield improvement. Some valuable genes that contribute to rice yield may be lost or lacked in the cultivated rice. Identification of the quantitative trait locus (QTL) for yield-related traits such as thousand-grain weight (TGW) from wild rice speices is desired for rice yield improvement. RESULTS In this study, sixteen TGW QTL were identified from a recombinant inbred line (RIL) population derived from the cross between the introgression line K1561 of Oryza minuta and the rice cultivar G1025. TGW12, One of most effective QTL was mapped to the region of 204.12 kb between the marker 2,768,345 and marker 2,853,491 of the specific locus amplified fragment (SLAF). The origin of TGW12 was tested using three markers nearby or within the TGW12 region, but not clarified yet. Our data indicated thirty-two open reading fragments (ORFs) were present in the region. RT-PCR analysis and sequence alignment showed that the coding domain sequences of ORF12, one MADS-box gene, in G1025 and K1561 were different due to alternative slicing, which caused premature transcription termination. The MADS-box gene was considered as a candidate of TGW12. CONCLUSION The effective QTL, TGW12, was mapped to a segment of 204.12 kb using RILs population and a MADS-box gene was identified among several candidate genes in the segment. The region of TGW12 should be further narrowed and creation of transgenic lines will reveal the gene function. TGW12 could be applied for improvement of TGW in breeding program.

中文翻译：

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基于野生稻（Oryza minuta）渗入系K1561和in稻G1025杂交的重组自交系群体，鉴定了负责水稻粒重的QTL TGW12。

背景技术栽培稻中有限的遗传资源可能阻碍进一步的产量提高。在栽培水稻中可能会丢失或缺乏一些有助于水稻产量的有价值的基因。为了提高水稻产量，需要鉴定与产量相关的性状（例如来自野生稻种的千粒重（TGW））的数量性状位点（QTL）。结果在本研究中，从重组自交系（RIL）群体中鉴定出16个TGW QTL，该自交系来自Oryza minuta渗入系K1561与水稻品种G1025之间的杂交。TGW12，最有效的QTL之一，被定位到特定基因座扩增片段（SLAF）的标记2,768,345和标记2,853,491之间的204.12 kb区域。TGW12的起源使用TGW12区域附近或内部的三个标记物进行了测试，但尚未弄清。我们的数据表明该区域存在32个开放阅读片段（ORF）。RT-PCR分析和序列比对表明，由于选择性切分，G1025和K1561中一个MADS-box基因ORF12的编码域序列不同，导致转录提前终止。MADS-box基因被认为是TGW12的候选基因。结论使用RILs群体将有效的QTL TGW12定位到204.12 kb的片段上，并在该片段的几个候选基因中鉴定了MADS-box基因。TGW12的区域应进一步缩小，转基因品系的建立将揭示该基因的功能。TGW12可用于改良TGW的育种程序。RT-PCR分析和序列比对表明，由于选择性切分，G1025和K1561中一个MADS-box基因ORF12的编码域序列不同，导致转录提前终止。MADS-box基因被认为是TGW12的候选基因。结论使用RILs群体将有效的QTL TGW12定位到204.12 kb的片段上，并在该片段的几个候选基因中鉴定了MADS-box基因。TGW12的区域应进一步缩小，转基因品系的建立将揭示该基因的功能。TGW12可用于改良TGW的育种程序。RT-PCR分析和序列比对表明，由于选择性切分，G1025和K1561中一个MADS-box基因ORF12的编码域序列不同，导致转录提前终止。MADS-box基因被认为是TGW12的候选基因。结论使用RILs群体将有效的QTL TGW12定位到204.12 kb的片段上，并在该片段的几个候选基因中鉴定了MADS-box基因。TGW12的区域应进一步缩小，转基因品系的建立将揭示该基因的功能。TGW12可用于改良TGW的育种程序。结论使用RILs群体将有效的QTL TGW12定位到204.12 kb的片段上，并在该片段的几个候选基因中鉴定了MADS-box基因。TGW12的区域应进一步缩小，转基因品系的建立将揭示该基因的功能。TGW12可用于改良TGW的育种程序。结论使用RILs群体将有效的QTL TGW12定位到204.12 kb的片段上，并在该片段的几个候选基因中鉴定了MADS-box基因。TGW12的区域应进一步缩小，转基因品系的建立将揭示该基因的功能。TGW12可用于改良TGW的育种程序。