Abdollahi Hamid, Ghahremani Zahra, Erfaninia Kobra, Mehrabi Rahim
Horticulture Research Department, Seed and Plant Improvement Institute, Karaj, Iran,
Photosynth Res. 2015 May;124(2):231-42. doi: 10.1007/s11120-015-0127-8. Epub 2015 Mar 28.
Erwinia amylovora is a necrogenic bacterium, causing the fire blight disease on many rosaceous plants. Triggering oxidative burst by E. amylovora is a key response by which host plants try to restrain pathogen spread. Electron transport chain (ETC) of chloroplasts is known as an inducible source of reactive oxygen species generation in various stresses. This research was performed to assess the role of this ETC in E. amylovora-host interaction using several inhibitors of this chain in susceptible and resistant apple and pear genotypes. All ETC inhibitors delayed appearance of disease necrosis, but the effects of methyl viologen, glutaraldehyde, and DCMU were more significant. In the absence of inhibitors, resistant genotypes showed an earlier and severe H2O2 generation and early suppression of redox dependent, psbA gene. The effects of inhibitors were corresponding to the redox potential of ETC inhibitory sites. In addition, delayed necrosis appearance was associated with the decreased disease severity and delayed H2O2 generation. These results provide evidences for the involvement of this ETC in host oxidative burst and suggest that chloroplast ETC has significant role in E. amylovora-host interaction.
梨火疫病菌是一种致坏死细菌，可在多种蔷薇科植物上引发火疫病。梨火疫病菌引发的氧化爆发是寄主植物试图抑制病原菌传播的关键反应。叶绿体电子传递链（ETC）是各种胁迫下活性氧产生的诱导源。本研究使用该链的几种抑制剂，在易感和抗性苹果及梨基因型中评估了该电子传递链在梨火疫病菌与寄主相互作用中的作用。所有电子传递链抑制剂均延迟了病害坏死的出现，但甲基紫精、戊二醛和敌草隆的效果更显著。在没有抑制剂的情况下，抗性基因型表现出更早且严重的过氧化氢产生以及对氧化还原依赖性psbA基因的早期抑制。抑制剂的作用与电子传递链抑制位点的氧化还原电位相对应。此外，坏死出现延迟与病害严重程度降低和过氧化氢产生延迟相关。这些结果为该电子传递链参与寄主氧化爆发提供了证据，并表明叶绿体电子传递链在梨火疫病菌与寄主的相互作用中具有重要作用。
