茉莉酸甲酯对烟草愈伤组织一些活性氧生成和相关酶活性的影响

Effects of Methyl Jasmonate on the Active Oxygen Production and Related Enzyme Activities in Tobacco Calli

烟草愈伤组织用茉莉酸甲酯(MJ, 1mgml-1)处理;同时将愈伤组织在含AIP(0.1mmol/L,水杨酸合成抑制剂)和/或AOA(1mmol/L,乙烯合成抑制剂)的MS培养基上进行暗培养,测定在活性氧产生和脂质过氧化中起作用的相关酶活性及一些代谢物的含量。结果表明,茉莉酸甲酯能激活超氧阴离子的产生,提高脂氧合酶同工酶1(LOX1)的活性从而启动脂质过氧化,对脂氧合酶同工酶3(LOX3)没有明显影响;降低过氧化氢(H2O2)的含量、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)及抗坏血酸过氧化物酶(APX)等保护酶的活性,减少了膜脂过氧化中有毒物质丙二醛(MDA)的含量。AIP和AOA都对MJ的作用有不同程度的影响。MJ调节超氧阴离子和过氧化氢生成以及相关酶活性是通过不同的信号转导途径,MJ调节超氧阴离子和MDA生成、SOD和APX活性很可能是通过乙烯起作用,且对MDA生成和APX活性的调节可能通过水杨酸起作用;MJ直接调节LOX1活性,但对LOX3活性没有明显作用。

The tobacco calli were cultured on MS or MS containing 0.1 mmo/L 2-aminoindan-2-phosphonic acid (AIP,inhibitor of SA synthesis,gift from Professor B. Mauch-Mani) or 1 mmol/L aminoxyacetic acid (AOA, inhibitor of ethylene synthesis) in dark (25±2℃),while methyl jasmonate (MJ) were sprayed to the calli. After treatment,the contents of malondialdehyde (MDA),active oxygen,hydrogen peroxide (H2O2) and the activities of superoxide dismutase (SOD),lipoxygenase (LOX1 and LOX3),catalase (CAT),ascorbate peroxidase (APX) were determined during 2-10 days. MJ largely decreased the content of MDA,H2O2, and the activities of SOD,CAT,APX. By contrast,MJ increased the activity of LOX1 and the content of active oxygen. However, MJ had little effects on the activity of LOX3. The treatment of AOA completely inhibited the effects of MJ on MDA,active oxygen,SOD and CAT,but,AIP had little effects on that substances and enzymes. AIP and AOA differed in the effects on the activity of APX and the MDA content,and had different effects on promoting the LOX activity induced by MJ. The results indicate there are different pathways of signal transduction in the activities of some enzymes and some metabolized substances that involved in the active oxygen burst and lipid peroxide. Ethylene plays a main role in inducing MDA,active oxygen and SOD,but SA had little effects on the induction of these substances. Thus,the effects of MJ are mainly induced by the ethylene pathway. However,SA is essential to the production of MDA and has a particular effect on modulating the activity of SOD under the condition of ethylene deficiency.