Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary.
Plant Biol (Stuttg). 2020 Jan;22(1):70-80. doi: 10.1111/plb.13030. Epub 2019 Jul 31.
The effects of elevated glutathione levels on defence responses to powdery mildew (Euoidium longipes) were investigated in a salicylic acid-deficient tobacco (Nicotiana tabacum cv. Xanthi NahG) and wild-type cv. Xanthi plants, where salicylic acid (SA) contents are normal. Aqueous solutions of reduced glutathione (GSH) and its synthetic precursor R-2-oxothiazolidine-4-carboxylic acid (OTC) were injected into leaves of tobacco plants 3 h before powdery mildew inoculation. SA-deficient NahG tobacco was hyper-susceptible to E. longipes, as judged by significantly more severe powdery mildew symptoms and enhanced pathogen accumulation. Strikingly, elevation of GSH levels in SA-deficient NahG tobacco restored susceptibility to E. longipes to the extent seen in wild-type plants (i.e. enhanced basal resistance). However, expression of the SA-mediated pathogenesis-related gene (NtPR-1a) did not increase significantly in GSH or OTC-pretreated and powdery mildew-inoculated NahG tobacco, suggesting that the induction of this PR gene may not be directly involved in the defence responses induced by GSH. Our results demonstrate that artificial elevation of glutathione content can significantly reduce susceptibility to powdery mildew in SA-deficient tobacco.
研究了在水杨酸缺乏型烟草（Nicotiana tabacum cv. Xanthi NahG）和野生型 cv. Xanthi 植株中，提高谷胱甘肽水平对防御白粉病（Euoidium longipes）反应的影响，其中水杨酸（SA）含量正常。还原型谷胱甘肽（GSH）及其合成前体 R-2-氧代噻唑烷-4-羧酸（OTC）的水溶液在白粉病接种前 3 小时被注入烟草叶片。与野生型植株相比，水杨酸缺乏型 NahG 烟草对白粉病的超敏性更为明显，表现为更严重的白粉病症状和增强的病原体积累。引人注目的是，在水杨酸缺乏型 NahG 烟草中提高 GSH 水平将其对白粉病的敏感性恢复到野生型植株的程度（即增强基础抗性）。然而，在 GSH 或 OTC 预处理和白粉病接种的 NahG 烟草中，SA 介导的病程相关基因（NtPR-1a）的表达并没有显著增加，这表明该 PR 基因的诱导可能不会直接参与 GSH 诱导的防御反应。我们的研究结果表明，人工提高谷胱甘肽含量可以显著降低水杨酸缺乏型烟草对白粉病的敏感性。
