Polyamine Oxidase Is One of the Key Elements for Oxidative Burst to Induce Programmed Cell Death in Tobacco Cultured Cells1
Polyamine Oxidase Is One of the Key Elements for Oxidative Burst to Induce Programmed Cell Death in Tobacco Cultured Cells1
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DOI：
10.1104/pp.106.080515
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发表时间：
2006-07
期刊：
影响因子：
7.4
通讯作者：
H. Yoda;Yoshinobu Hiroi;H. Sano
中科院分区：
文献类型：
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作者：
H. Yoda;Yoshinobu Hiroi;H. Sano
程序性细胞死亡在植物防御系统的过敏反应中起着至关重要的作用。触发它的成分之一是过氧化氢，它是通过多种途径产生的。一个例子是多胺氧化，但这一点的直接证据有限。在本文中，我们使用由烟草（Nicotiana tabacum）培养细胞及其引发子隐黄蛋白组成的模型系统研究了多胺氧化酶、过氧化氢和程序性细胞死亡之间的关系。当用隐黄蛋白处理培养的细胞时，程序性细胞死亡发生，并伴有明显的 DNA 降解模式。过氧化氢水平同时增加，质外体中的多胺氧化酶活性也增加。在α-二氟甲基-Orn（一种多胺生物合成抑制剂）存在下进行相同的处理，过氧化氢的产生受到抑制，并且没有发生程序性细胞死亡。分离存在于质外体中的编码烟草多胺氧化酶的基因并用于构建RNAi转基因细胞系。当用隐黄素处理这些细胞系时，多胺不会降解，而是分泌到培养基中，并且几乎不产生过氧化氢，同时抑制细胞死亡。有丝分裂原激活的蛋白激酶（伤口和水杨酸诱导的蛋白激酶）的活性也受到抑制，表明磷酸化级联涉及多胺氧化引起的细胞死亡。这些结果表明，多胺氧化酶是氧化爆发的关键元素，这对于诱导程序性细胞死亡至关重要，而丝裂原激活蛋白激酶是介导该途径的因素之一。
Programmed cell death plays a critical role during the hypersensitive response in the plant defense system. One of components that triggers it is hydrogen peroxide, which is generated through multiple pathways. One example is proposed to be polyamine oxidation, but direct evidence for this has been limited. In this article, we investigated relationships among polyamine oxidase, hydrogen peroxide, and programmed cell death using a model system constituted of tobacco (Nicotiana tabacum) cultured cell and its elicitor, cryptogein. When cultured cells were treated with cryptogein, programmed cell death occurred with a distinct pattern of DNA degradation. The level of hydrogen peroxide was simultaneously increased, along with polyamine oxidase activity in apoplast. With the same treatment in the presence of α-difluoromethyl-Orn, an inhibitor of polyamine biosynthesis, production of hydrogen peroxide was suppressed and programmed cell death did not occur. A gene encoding a tobacco polyamine oxidase that resides in the apoplast was isolated and used to construct RNAi transgenic cell lines. When these lines were treated with cryptogein, polyamines were not degraded but secreted into culture medium and hydrogen peroxide was scarcely produced, with a concomitant suppression of cell death. Activities of mitogen-activated protein kinases (wound- and salicylic acid-induced protein kinases) were also suppressed, indicating that phosphorylation cascade is involved in polyamine oxidation-derived cell death. These results suggest that polyamine oxidase is a key element for the oxidative burst, which is essential for induction of programmed cell death, and that mitogen-activated protein kinase is one of the factors that mediate this pathway.