H2O2参与水杨酸诱导丹参培养细胞中丹酚酸B合成的信号转导

过氧化氢(Hydrogen peroxide,H2O2)为活性氧(Reactive oxygen species,ROS)的一种,存在于许多生物体系中并介导植物中多种生理和生化过程。为了探讨H2O2作为信号分子在水杨酸(Salicylic acid,SA)诱导丹参培养细胞合成丹酚酸B(Salvianolic acid B,Sal B)过程中的作用,分别考察了SA和H2O2、过氧化氢酶(Catalase,CAT)、二甲基硫脲(2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide,DMTU)及咪唑(Imidazole,IMD)对苯丙氨酸解氨酶(Phenylalanine ammonia-lyase,PAL)和酪氨酸氨基转移酶(Tyrosine aminotransferase,TAT)的活性及Sal B含量的影响。结果表明,SA处理可有效地诱导丹参培养细胞中H2O2产生、PAL和TAT活性升高以及Sal B合成积累量的增加;外源施加10～30 mmol/L H2O2也可以有效促进PAL、TAT活性升高和Sal B合成积累量的增加;用H2O2的清除剂CAT处理发现,CAT对SA或外源H2O2诱导的Sal B合成积累具有消除作用,说明H2O2可能作为SA诱导Sal B积累过程中的上游信号分子起作用;用H2O2淬灭剂DMTU处理,可以有效抑制SA对Sal B合成的促进作用;用质膜烟酰胺腺嘌呤二核苷酸(Nicotinamide vadenine dinucleotide phosphate,NADPH)氧化酶(H2O2来源的主要酶)抑制剂IMD处理,可以抑制Sal B的合成,但这种抑制效果可以部分被外源施加的SA削弱,说明通过HADPH氧化酶产生的H2O2受阻时,SA诱导的Sal B合成积累也会受到抑制。表明H2O2是介导SA诱导丹参培养细胞中Sal B合成积累的信号分子。

Hydrogen peroxide is involved in the signal transduction of salicylic acid-induced salvianolic acid B biosynthesis in Salvia miltiorrhiza cell cultures

Hydrogen peroxide (H2O2), one of reactive oxygen species, is widely generated in many biological systems, and it mediates various physiological and biochemical process in plants. To investigate the role of H2O2 as a signaling molecule in the process of salicylic acid (SA)-induced Salvianolic acid B (Sal B) accumulation, we separately inspected the cultured cells of Salvia miltiorrhiza with SA, H2O2, Catalase (CAT), 2-(4-carboxy-2-phenyl)-4,4,5,5- tetramethylimidazoline-1-oxyl-3-oxide (DMTU) and Imidazole (IMD) to investigate the influence on the activity of phenylalanine ammonia-lyase (PAL) and tyrosine aminotransferase (TAT) and the accumulation of Sal B. Treatment of S. miltiorrhiza cells with SA resulted in an increase of H2O2, the increase of PAL and TAT and accumulation of Sal B. Exogenous application of 10~30 mmol/L H2O2 was found to effectively increase PAL and TAT activity as well as the Sal B content. CAT, a H2O2 scavenger, eliminated the Sal B-accumulating effects of exogenous H2O2 and SA. These indicated that H2O2 may serve as an upstream signaling molecule in the SA-induced accumulation of Sal B signal transduction pathway. Disposed by DMTU, a chemical trap for H2O2, as observed to be effective in inhibiting SA-induced accumulation of Sal B. IMD strongly inhibits the activity of NADPH oxidase, which is one of the main sources of H2O2 formation in plant cells. IMD treatment strongly inhibited the accumulation of Sal B in cultured cells of S. miltiorrhiza, but the effects of IMD, can be partially reversed by the exogenous SA. The accumulation of Sal B was blocked once the generation of H2O2 by NADPH oxidase was inhibited, and H2O2 served as signaling molecule mediated the SA-induced Sal B accumulation.