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异黄酮合酶基因(isoflavone synthase,IFS)是合成异黄酮的关键酶基因之一,能够在转录水平对异黄酮的生物合成进行调控。为研究大豆籽粒中IFS基因与大豆异黄酮合成的关系,本研究选择8个不同地理来源的大豆品种,利用高效液相色谱法(HPLC)测定大豆籽粒中异黄酮4种主要组分含量(染料木素,大豆甙元,染料木甙和大豆甙),并利用荧光定量PCR的方法测定了IFS1基因(IFS基因的同源基因之一)在大豆籽粒中的相对表达量。结果表明:大豆异黄酮4种主要组分含量在不同品种中差异较大,在所测试的品种中,中品03-5368和中豆27籽粒的总异黄酮含量较高,分别达到1 873.136μg/g、1 526.203μg/g,兴县灰皮支和Wiliams82总异黄酮含量较低,分别为1 258.591μg/g和1 255.300μg/g;大豆籽粒中大豆异黄酮总含量与籽粒中IFS1基因的相对表达量呈显著正相关(r=0.995 5,P<0.000 1),大豆异黄酮4种主要成分中的染料木素和大豆甙与IFS1基因的相对表达量也成正相关,这一结果说明IFS1基因作为苯丙氨酸合成路径中进入异黄酮合成途径的第一个酶,在异黄酮化合物合成中起关键作用。本研究不仅可以为明确大豆异黄酮合成途径中IFS基因分子调控机理提供科学理论依据,而且能够为高异黄酮生物合成和大豆品质改良奠定理论基础。
Isoflavone synthase (IFS) is one of the key enzyme genes for the synthesis of isoflavones, and can regulate the biosynthesis of isoflavones at the transcriptional level. In order to study the relationship between IFS gene and soybean isoflavone synthesis in soybean, eight soybean cultivars from different geographical origins were selected to determine the content of four major isoflavone components in soybean seeds by high performance liquid chromatography (HPLC) Lignin, daidzein, genistin and daidzin). The relative expression level of IFS1 gene (one of IFS gene) in soybean grain was determined by fluorescence quantitative PCR. The results showed that the contents of four main components of soybean isoflavones varied greatly among different varieties. Among the tested varieties, the content of total isoflavones of Zhongyou 03-5368 and Zhongzhong 27 were higher, reaching 1873.136μg / g and 1 526.203 μg / g respectively, while the total isoflavones content of Hedysarum scabies and Wiliams82 was lower, which were 1 258.591 μg / g and 1 255.300 μg / g, respectively. The total content of soybean isoflavones in soybean seeds was significantly correlated with the IFS1 gene (R = 0.995 5, P <0.0001). There was also a positive correlation between genistein and daidzein relative expression of IFS1 in the four main components of soybean isoflavones The IFS1 gene, as the first enzyme entering the isoflavone synthesis pathway in the phenylalanine synthesis pathway, plays a key role in isoflavone synthesis. This study not only provides a scientific theoretical basis for clarifying the molecular regulation mechanism of IFS in the synthetic pathway of soybean isoflavones, but also lays a theoretical foundation for the biosynthesis of isoflavones and the improvement of soybean quality.