干旱胁迫对苗期大豆异黄酮合成的影响

以不同耐旱性的2个大豆品种(高耐旱JP-6、低耐旱JP-16)为研究材料,采用高效液相色谱和实时荧光定量PCR技术,分析不同时间持续干旱胁迫下,大豆叶片和根系中异黄酮的积累变化及关键酶基因的表达情况.结果表明:大豆根部异黄酮含量显著高于叶部,而异黄酮关键酶基因的表达量则在叶片中更高,耐旱品种JP-6根部的异黄酮积累量更大.随着干旱胁迫持续时间的增加,不同耐旱品种的异黄酮合成与积累变化规律存在显著差异:强耐旱品种JP-6的根和叶中,异黄酮积累量均呈现先下降后升高的趋势;而弱耐旱品种JP-16则相反,异黄酮积累量在不同部位中均呈现先上升后降低的趋势;除JP-6叶中C4H、4CL、IFS2等异黄酮合成上游基因外,其他不同品种、不同部位的关键酶基因表达量均随着干旱胁迫持续时间的增加,呈现先下降后上升的趋势.大豆叶片是异黄酮的主要合成部位,大豆根部也存在少量的异黄酮合成.弱耐旱大豆根部的异黄酮合成和最终积累量均较低,强耐旱品种则较高.根部异黄酮积累量高的大豆品种,其耐旱性更强.

Effects of drought stress on biosynthesis of isoflavones in soybean seedling

In this present study, two soybean cultivars with different drought tolerance in serial number of JP-6 (high drought-tolerant species) and JP-16 (low drought-tolerant species) were researched. The HPLC and real-time PCR analyses were used to determine the isoflavone contents and relative expression levels of key genes, which encoded isoflavone synthesis relative enzymes in lea-ves and roots under different drought stress levels, respectively. The results indicated that the isoflavone contents in roots were significantly higher than that in leaves, whereas the relative expression of isoflavone synthetic enzyme related genes in leaves was significantly higher than that in roots. Analysis of isoflavone accumulation by comparing two different drought tolerance soybean cultivars found that the isoflavone accumulation in roots of JP-6 was greater than that in others. With increa-sing levels of the drought stress, there were significant differences in both isoflavone synthesis and accumulation between JP-6 and JP-16 soybean cultivars. In JP-6, the isoflavone accumulation in root and leaf increased after slight decreasing, while the opposite result was obtained in JP-16, in which the isoflavone accumulation in different parts were decreased after slight increasing. The expression of isoflavone synthesis relative enzyme genes presented a trend that decreased and then gradually increased with the increasing level of drought stress, except C4H, 4CL and IFS2 which were synthesis genes upstream of isoflavones in leaves of JP-6. Soybean isoflavones were mainly synthesized in leaves, little was synthesized in roots. The isoflavone synthesis and accumulation of low drought-tolerant species were scare, while those of high drought-resistant variety were relatively higher. The variety with high isoflavone accumulation in the root was more drought-resistant.