仿生型信号分子对烟草生物碱的抑制作用机制

Mechanism of Inhibition Action of Bionic Signal Molecule to Tobacco Alkaloid

为了明确仿生型信号分子(BSM)抑制打顶后烟草生物碱积累的机制,研究了打顶、打顶后立即涂抹BSM以及对照植株的茉莉酸(JA)含量、脂氧合酶(LOX)和鸟氨酸脱羧酶(ODC)酶活性的变化。结果表明:打顶后烟草叶片和根部的JA含量增加,而BSM处理可以降低JA含量的增加幅度,且对根部JA含量有显著的抑制作用,在处理后6 h根部JA降低了38.5%;烟草打顶后的24 h内叶片中LOX活性大幅度增加,BSM处理可以使LOX活性下降,在峰值处LOX活性降低了25.0%;根部的ODC酶在打顶后迅速增加,BSM同样对其活性有抑制作用,在峰值处ODC活性降低了11.2%。BSM抑制打顶后烟草植株中生物碱的积累机制是抑制了创伤信号路径上游的LOX活性,继而抑制了JA的含量及ODC的活性,从而最终降低了烟草植株中生物碱的含量。

For better understanding the mechanism of inhibition action of bionic signal molecule （BSM） to the alkaloid accumulation in tobacco after topping, the changes of j asmonic acid （JA） content, and the activities of lipoxygenase （LOX） and ornithine decarboxylase （ODC） in tobacco plants under different treatments, including topping, topping followed by BSM application, and the control, were analyzed. The results showed that： 1） JA content increased in tobacco leaves and roots after topping, while BSM application would inhibit the increasing rate of JA in roots and leaves, particularly in roots, which was reduced by 38.5% in 6 hours after application. 2） LOX activity in tobacco leaves obviously increased within 24 hours after topping. BSM application decreased LOX activity, it decreased the activity peak by 25.0%. 3） ODC activity in roots increased rapidly after topping. BSM application inhibited ODC activity, it reduced the activity peak by 11.2%. 4） By inhibiting LOX activity at the upstream of the wound signal path, then inhibiting JA content and ODC activity, BSM lowered alkaloid accumulation in tobacco after