Analysis of nitric oxide signaling functions in tobacco cells challenged by the elicitor cryptogein
Analysis of nitric oxide signaling functions in tobacco cells challenged by the elicitor cryptogein
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DOI：
10.1104/pp.104.038968
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发表时间：
2004-05-01
期刊：
影响因子：
7.4
通讯作者：
Wendehenne, D
中科院分区：
文献类型：
--
作者：
Lamotte, O;Gould, K;Wendehenne, D
一氧化氮（NO）是植物防御反应中的重要细胞介质。然而，NO参与这一信号通路的生化机制的阐明仍处于起步阶段。我们以前证明，cryptogein，烟草防御反应的激发子，触发一个NO爆发在几分钟内从烟草叶（烟草品种Xanthi）的表皮部分。在这里，我们调查的信号事件，介导NO的生产，并分析在隐地蛋白转导通路中的NO信号活动。使用流式细胞仪和荧光分光光度法，我们观察到，在烟草细胞悬浮液中的隐地蛋白诱导的NO的产生是敏感的一氧化氮合酶抑制剂，并可能催化的变种P，最近确定的病原体诱导的植物一氧化氮合酶。NO的合成受到Ca 2+内流和磷酸化事件的信号级联的严格调节。使用烟草细胞组成型表达的Ca 2+报告apoaequorin在胞质溶胶中，我们已经表明，NO参与的cryptogein介导的升高胞质游离Ca 2+通过动员Ca 2+从细胞内存储。NO供体二乙胺NONOate促进细胞内游离Ca ~（2+）浓度的增加，这对细胞内Ca ~（2+）通道抑制剂敏感。此外，NO似乎参与导致编码热休克蛋白TLHS-1、乙烯形成酶cEFE-26的转录物积累和细胞死亡的途径。相反，NO不作用于激发子诱导的丝裂原活化蛋白激酶的激活、阴离子通道的开放、GST、LOX-1、PAL和PR-3基因的表达的上游。总的来说，我们的数据表明，NO密切参与信号转导过程，导致隐地蛋白诱导的防御反应。
Nitric oxide (NO) has recently emerged as an important cellular mediator in plant defense responses. However, elucidation of the biochemical mechanisms by which NO participates in this signaling pathway is still in its infancy. We previously demonstrated that cryptogein, an elicitor of tobacco defense responses, triggers a NO burst within minutes in epidermal sections from tobacco leaves (Nicotiana tabacum cv Xanthi). Here, we investigate the signaling events that mediate NO production, and analyze NO signaling activities in the cryptogein transduction pathway. Using flow cytometry and spectrofluorometry, we observed that cryptogein-induced NO production in tobacco cell suspensions is sensitive to nitric oxide synthase inhibitors and may be catalyzed by variant P, a recently identified pathogen-inducible plant nitric oxide synthase. NO synthesis is tightly regulated by a signaling cascade involving Ca2+ influx and phosphorylation events. Using tobacco cells constitutively expressing the Ca2+ reporter apoaequorin in the cytosol, we have shown that NO participates in the cryptogein-mediated elevation of cytosolic free Ca2+ through the mobilization of Ca2+ from intracellular stores. The NO donor diethylamine NONOate promoted an increase in cytosolic free Ca2+ concentration, which was sensitive to intracellular Ca2+ channel inhibitors. Moreover, NO appears to be involved in the pathway(s) leading to the accumulation of transcripts encoding the heat shock protein TLHS-1, the ethylene-forming enzyme cEFE-26, and cell death. In contrast, NO does not act upstream of the elicitor-induced activation of mitogen-activated protein kinase, the opening of anion channels, nor expression of GST, LOX-1, PAL, and PR-3 genes. Collectively, our data indicate that NO is intimately involved in the signal transduction processes leading to cryptogein-induced defense responses.