茉莉酸甲酯诱导的苹果悬浮细胞的防卫响应

Methyl Jasmonate-induced Defense Responses of Apple Suspension Cells

以苹果悬浮细胞为试材,以硝普钠(SNP)为一氧化氮(NO)供体,L-NNA(Nx-nitro-L-ar-ginine)为一氧化氮合酶(NOS)抑制剂,PTIO(2-phenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide)为NO清除剂,研究了茉莉酸甲酯(MeJA)处理苹果悬浮细胞诱发NO和H2O2信号分子及其对PAL酶活性、植保素和丙二醛(MDA)的影响。结果表明,MeJA处理能明显诱发NO生成,在处理6h时NO生成量达到峰值,而L-NNA和PTIO则能够抑制NO生成。另外,MeJA处理也显著提高了细胞内的H2O2水平,而SNP单独处理不能提高H2O2水平。在各种处理中,PAL活性以及植保素和MDA含量均表现出先升后降趋势,分别在4h或6h时达到峰值。本研究结果揭示了MeJA可以激发NO生成,而细胞内H2O2水平的提高则是MeJA和NO协同作用的结果,植保素和MDA含量以及PAL活性的提高主要受NO的诱导,但也存在其它诱导途径。

Meythyl jasmonate （MeJA） is an elicitor for defensive responses of plant to pathogens, while NO and H2O2 are signal molecules related to defensive responses. In this study, MeJA-induced defense responses of apple suspension cells were monitored in NO release, H2O2 accumulation, PAL activity and MDA content, with sodium nitroprusside （SNP） as a NO donor, L-NNA （Nx-nitro-L-arginine） as NOS inhibitor and PTIO （2-phenyl-4, 4, 5, 5-tetramethyl-imidazoline-1-oxyl-3-oxide） as NO scavengers. The results showed that apple suspension cells constantly produced NO and reached a peak release at 6 h when exposed to MeJA treatment. On the contrary, L-NNA and PTIO inhibited the generation of NO in cells. MeJA treatment also led to a great increase in H2O2 level in suspension cells, but SNP treatment did not. In addition, PAL ac- tivities as well as MDA and phytoalexin contents displayed similar dynamic curves with different treatments, increasing firstly and then decreasing with peak activity or content at 4 to 6 hours. Those findings indicated that MeJA induced the generation of NO, and then MeJA and NO worked together to increase H2O2 level in suspension cells. Phytoalexin and MDA increase as well as PAL activity enhancement were mainly induced by NO, although it seemed other signals involved.