Plant Protection Institute, Centre for agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary.
Phytopathology. 2012 Sep;102(9):848-56. doi: 10.1094/PHYTO-01-12-0012-R.
Pretreatment of tobacco leaves with low concentrations (5 to 10 mM) of H₂O₂ suppressed hypersensitive-type necrosis associated with resistance to Tobacco mosaic virus (TMV) or Pseudomonas syringae pv. phaseolicola. The same pretreatment resulted in suppression of normosensitive necrosis associated with susceptibility to Botrytis cinerea. This type of H₂O₂-mediated, induced disease symptom resistance correlated with enhanced host antioxidant capacity, i.e., elevated enzymatic activities of catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (POX) after viral and bacterial infections. Induction of genes that encode the antioxidants superoxide dismutase (SOD), CAT, and APX was also enhanced early after TMV infection. Artificial application of SOD and CAT suppressed necroses caused by viral, bacterial, or fungal pathogens similarly as H₂O₂ pretreatment, implying that H₂O₂-mediated symptom resistance operates through enhancement of plant antioxidant capacity. Pathogen multiplication was not significantly affected in H₂O₂-pretreated plants. Salicylic acid (SA), a central component of plant defense, does not seem to function in this type of H₂O₂-mediated symptom resistance, indicated by unchanged levels of free and bound SA and a lack of early up-regulation of an SA glucosyltransferase gene in TMV-infected H₂O₂-pretreated tobacco. Taken together, H₂O₂-mediated, induced resistance to necrotic symptoms in tobacco seems to depend on enhanced antioxidant capacity.
用低浓度（5 至 10mM）的 H₂O₂预处理烟叶可以抑制与烟草花叶病毒（TMV）或丁香假单胞菌 pv. phaseolicola 抗性相关的过敏性坏死。相同的预处理会抑制与灰葡萄孢菌易感性相关的正常坏死。这种类型的 H₂O₂介导的诱导性疾病症状抗性与增强的宿主抗氧化能力相关，即在病毒和细菌感染后，过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）和愈创木酚过氧化物酶（POX）的酶活性升高。感染 TMV 后，抗氧化剂基因（编码超氧化物歧化酶（SOD）、CAT 和 APX）的诱导也增强。人工应用 SOD 和 CAT 可抑制病毒、细菌或真菌病原体引起的坏死，与 H₂O₂预处理相似，这表明 H₂O₂介导的症状抗性通过增强植物的抗氧化能力来发挥作用。在 H₂O₂预处理的植物中，病原体的繁殖并没有受到显著影响。水杨酸（SA）是植物防御的核心成分，在这种 H₂O₂介导的症状抗性中似乎不起作用，这表现在游离和结合的 SA 水平没有变化，以及在 TMV 感染的 H₂O₂预处理烟草中缺乏早期上调 SA 葡萄糖基转移酶基因。综上所述，烟草中与坏死症状相关的 H₂O₂介导的诱导抗性似乎依赖于增强的抗氧化能力。
