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Waxy(Wx)基因在调控直链淀粉含量形成过程中起着重要的作用,是稻米蒸煮食味品质的一个关键决定因素。在本项研究中,我们以直链淀粉含量为8.7%和10.2%的优质稻品种‘青香软粳’和‘南粳46’为主要研究对象,初步分析并探讨了这两个优质稻品种稻米低直链淀粉形成的分子调控机理。结果显示,虽然都为Wx-II型粳稻品种,‘南粳46’的Wx基因在启动子1773位置存在AA/CT的变异,‘南粳46’和‘青香软粳’的Wx基因在启动子+693位置具有G/A位点多态性。转录水平分析表明,在‘南粳46’和‘青香软粳’稻米发育过程中,Wx基因的表达模式有较大的差异,可能与其启动子序列的多态性相关,AA/CT变异处于Wx基因的转录调控区。Wx基因启动子后+693位点的多态性与已报道Wxmq多态性位点之一相同,引起Arg158/His158的变异;生物信息学软件分析表明,该位点处于底物进入Wx蛋白催化中心的袋口上,Arg158/His158位点的变异可能影响到底物进入Wx蛋白催化活性中心的速率,从而影响稻米直链淀粉的合成过程和含量。文章丰富了Wx基因多态性的研究,为进一步验证其核苷酸变异与稻米直链淀粉含量的相关性奠定了基础。
The Waxy (Wx) gene plays an important role in the regulation of amylose content formation and is a key determinant of rice cooking and eating quality. In this study, we mainly focused on the cultivars ’Qingxiang soft japonica’ and ’Nanjing 46’ with high quality rice varieties with 8.7% and 10.2% amylose content. We analyzed and discussed the two high quality rice varieties Molecular Mechanism of Low Amylose Formation in Rice. The results showed that there were AA / CT variations in the Wx gene of Nanjing 46 at the position of promoter 1773 in both Wx-II japonica rice varieties and the Wx gene in Nanjing 46 and Qingxiangjingjing There is a G / A polymorphism in the +693 position. The transcriptional level analysis showed that Wx gene expression patterns were significantly different during the development of ’Nanjing 46’ and ’Qingxiang Soft Japonica’ rice, which may be related to the polymorphism of its promoter sequence and AA / CT variation Wx gene transcriptional regulatory region. The polymorphism at the +693 site of Wx gene promoter was the same as one of the reported Wxmq polymorphisms, which caused the mutation of Arg158 / His158. Analysis by bioinformatics software showed that this site was at the site of substrate entry into Wx protein catalysis Variation in the Arg158 / His158 site on the pocket of the center may affect the rate at which the substrate enters the catalytic active site of the Wx protein, thereby affecting the amylose synthesis process and content in rice. The article enriched the study of Wx gene polymorphism, which laid the foundation for further verifying the correlation between nucleotide variation and rice amylose content.