谷子SiPSY1基因与米色形成相关性分析

为明确谷子八氢番茄红素合成酶基因与谷子米色形成的相关性,本研究从黄色和白色2种不同米色谷子中克隆出SiPSY1基因的cDNA全长序列,并进行生物信息学分析,同时,利用实时荧光定量PCR方法检测该基因在谷子米色形成过程中的表达模式。结果表明,SiPSY1基因编码序列(CDS)全长为1 248 bp,共编码415个氨基酸。SiPSY1蛋白的理论分子量为46.866 kDa,等电点为8.97,为不稳定亲水性蛋白。该蛋白的二级结构由α螺旋(57.35%)、不规则卷曲(29.64%)、延伸链结构(9.88%)和β转角(3.13%)四种结构组成。SiPSY1蛋白与玉米ZmPSY1的同源性较高,二者的亲缘关系较近。在谷子米色形成的初期和中期,黄色米色品种籽粒中SiPSY1基因的表达水平显著高于白色米色品种,而在米色形成后期,该基因在白色米色品种中的表达水平显著提高,并高于在黄色米色品种中的表达水平。随着籽粒成熟米色的形成,SiPSY1基因在黄色米色品种七月黄中的表达量呈先上升后显著下降的趋势,在白色米色品种中呈逐渐上升的趋势。通过对SiPSY1基因结构和表达特性的分析,初步推测谷子米色差异及形成与SiPSY1基因结构无关,而与基因的表达特性有一定的相关性。本研究结果为进一步阐明SiPSY1基因的功能以及谷子米色形成的分子机制奠定了基础。

Correlation Analysis Between SiPSY1 Gene and Millet Color Formation in Foxtail Millet

In order to clarify the relationship between the SiPSY and the formation of millet color, the full-length cDNA sequence of SiPSY1 gene was cloned from two foxtail millet varieties with colors of yellow and white, and bioinformatics analysis was performed. Meanwhile, the expression pattern of SiPSY1 was detected by real-time qPCR. The results showed that the full length of CDS of SiPSY1 gene was 1 248 bp, encoding 415 amino acids. The theoretical molecular weight of SiPSY1 protein was 46.866 kDa, the isoelectric point was 8.97, and the protein was an unstable hydrophilic protein. The secondary structure of the protein was composed of α-helix (57.35%), random coil (29.64%), extended strand (9.88%) and β-turn (3.13%). The SiPSY1 protein had high homology with maize ZmPSY1, and their genetic relationship was close. The expression level of SiPSY1 in the varieties with yellow millet color was significantly higher than that in white millet varieties in the early and middle stages of millet color formation, while in the late stage of millet color formation, the expression level of SiPSY1 in white millet varieties was increased significantly, higher than that in varieties with yellow millet color. With the formation of millet color, the expression of SiPSY1 gene in yellow millet varieties Qiyuehuang showed a trend of increasing first and then decreasing, while gradually increasing in white varieties. Through the analysis of the structure and expression pattern of SiPSY1 gene, it was preliminarily speculated that the difference and formation of millet color were not related to the structure of SiPSY1 gene, but had a certain correlation with the expression patterns of the gene. The results laid a foundation for further elucidating the function of SiPSY1 and the molecular mechanism of millet color formation.