光照对大豆叶片苯丙氨酸裂解酶(PAL)基因表达及异黄酮合成的调节

Light Regulation of the Expression of PAL Gene in Soybean Leaves and Isoflavone Synthesis

异黄酮是大豆体内特别是种子中积累的一类重要的次生代谢产物 ,它具有特殊的生物效能。本实验在不同水平 (RNA/酶 /产物 )上研究不同光照条件对大豆叶片异黄酮合成过程中的第一个关键酶苯丙氨酸氨基裂解酶 (PAL)基因表达的影响。研究发现 ,在光照条件下pal表达量比黑暗条件下高 ,而且其影响程度与品种有关系 ,种子中异黄酮含量低的品种表现更敏感 ;其mRNA的合成受红光、蓝光、紫外光的促进 ,其中紫外光最有效 ;随着处理时间的延长 ,mRNA的量和酶活性增加 ;但是在异黄酮的积累水平上 ,随着紫外光照射时间的延长 。

Isoflavones are a group of important secondary metabolites accumulated in soybean plant ( Glycine max Merri) especially in seeds, and have a lot of important functions. The accumulation of isoflavones in soybean leaves can be induced by light. Our experiments aimed at the soybean phenylalanine ammonia_lyase (PAL) gene expression under different light conditions. It was found that expression of pal in light was higher than that in darkness. The effects which depend on different varieties was more sensitive to light in the variety which has lower contents of flavones in seeds. Red light (R), Blue light (B) and UV light (UV) increased PAL mRNA abundance, and UV was the most effective light. With the elongation of treatment time, the mRNA abundance for pal and activity of the enzyme increased. The isoflavones accumulation showed to decline with the UV time. This pattern was not consistent with that at the level of mRNA and the enzyme.