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Molecular mechanisms of the generation of pigmented seeds from yellow soybean plants

黄大豆植物产生色素种子的分子机制

基本信息

批准号：
17580003
负责人：
SENDA Mineo
金额：
$ 2.53万
依托单位：
Hirosaki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17580003/
关键词：
yellow soybean pigmented seeds I gene mutation CHS gene PTGS GmIRCHS transgenic Arabidopsis プロモーター領域 GUS染色組織発現構造変異種皮着色抑制相同組換え 2本鎖RNA RT-PCR 欠失変異インバーテッドリピート配列

项目摘要

Most commercial soybean varieties have yellow seeds due to loss of pigmentation in the seed coat. The I gene inhibits pigmentation over the entire seed coat, resulting in a uniform yellow color of mature harvested seeds. We previously demonstrated that the inhibition of seed coat pigmentation by the I gene results from post-transcriptional gene silencing (PTGS) of chalcone synthase (CHS) genes. Little is known about the structure of the I gene and the mechanism by which it induces PTGS of CHS genes. In this study, we identified a candidate of the I gene, GmIRCHS, which consists of a 5'-portion of a DnaJ-like gene containing a promoter region and a perfect inverted repeat (IR) of 1.1-kb truncated CHS3 sequences (5'-ΔCHS3 and 3'-ΔCHS3). RT-PCRs indicated the existence of the read-through product from 5'-ΔCHS3 to 3'-ΔCHS3 and the dsRNA region of ΔCHS3, suggesting that dsRNA of ΔCHS3 could be transcribed from GmIRCHS and could induce PTGS of CHS genes. Moreover, the IR structure of ΔCHS3 in GmIRCHS was lost in the soybean mutants in which I was changed to i, supporting the conclusion that GmIRCHS is the I gene. Finally, to analyze the expression pattern of GmIRCHS, we constructed transgenic Arabidopsis expressing a reporter gene fusion of the GmIRCHS promoter and the β-glucronidase (GUS) gene. Intense staining was not observed in the seed coat, indicating that GmIRCHS is not specifically expressed in the seed coat tissues.

大多数商业大豆品种由于种皮中色素的损失而具有黄色种子。I基因抑制整个种皮的色素沉着，导致成熟收获的种子呈均匀的黄色。我们以前证明，抑制种皮色素沉着的I基因的结果从转录后基因沉默（PTGS）的查耳酮合酶（CHS）基因。关于I基因的结构及其诱导CHS基因PTGS的机制知之甚少。在本研究中，我们鉴定了I基因的候选基因GmIRCHS，其由含有启动子区的DnaJ样基因的5 '部分和1.1-kb截短CHS 3序列（5'-Δ CHS 3和3 '-Δ CHS 3）的完美反向重复（IR）组成。RT-PCR结果表明，存在5 '-Δ CHS 3到3'-Δ CHS 3的通读产物和Δ CHS 3的dsRNA区域，表明Δ CHS 3的dsRNA可以从GmIRCHS转录，并能诱导CHS基因的PTGS。此外，在I突变为i的突变体中，GmIRCHS中Δ CHS 3的IR结构丢失，支持GmIRCHS是I基因的结论。最后，为了分析GmIRCHS的表达模式，我们构建了表达GmIRCHS启动子和β-葡萄糖醛酸酶（GUS）基因的报告基因融合体的转基因拟南芥。在种皮中没有观察到强烈的染色，表明GmIRCHS在种皮组织中没有特异性表达。