NO way back:: nitric oxide and programmed cell death in Arabidopsis thaliana suspension cultures
NO way back:: nitric oxide and programmed cell death in Arabidopsis thaliana suspension cultures
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DOI：
10.1046/j.1365-313x.2000.00911.x
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发表时间：
2000-12-01
期刊：
影响因子：
7.2
通讯作者：
Neill, SJ
中科院分区：
文献类型：
--
作者：
Clarke, A;Desikan, R;Neill, SJ
最近的研究表明，在植物与病原体相互作用过程中，一氧化氮（NO）参与了过敏反应（HR）的诱导。在这里，我们证明了拟南芥悬浮培养在应对无毒细菌的挑战时产生了升高的NO水平，并且使用NO供体，表明这些升高的NO水平足以诱导拟南芥细胞独立于活性氧（ROS）而死亡。我们还提供证据表明，NO诱导的细胞死亡是程序性细胞死亡（PCD）的一种形式，需要基因表达，并且具有哺乳动物细胞PCD的许多特征：NO诱导拟南芥细胞的染色质凝集和caspase样活性，而caspase-1抑制剂Ac-YVAD-CMK可阻断NO诱导的细胞死亡。在哺乳动物细胞中介导NO反应的第二信使是cGMP，由鸟苷酸环化酶产生。鸟苷酸环化酶的特异性抑制剂阻断了no诱导的拟南芥细胞死亡，这种抑制作用被细胞渗透性cGMP类似物8Br-cGMP逆转，尽管单独8Br-cGMP不会诱导细胞死亡或增强no诱导的细胞死亡。这表明cGMP的合成是必需的，但不是拟南芥no诱导细胞死亡的充分条件。凝胶蛋白激酶实验表明，NO激活了潜在的丝裂原活化蛋白激酶（MAPK），尽管哺乳动物MAPK活化的特异性抑制剂PD98059可以阻断h2o2诱导的细胞死亡，但却不能抑制NO的作用。
Recent research has implicated nitric oxide (NO) in the induction of the hypersensitive response (HR) during plant-pathogen interactions. Here we demonstrate that Arabidopsis suspension cultures generate elevated levels of NO in response to challenge by avirulent bacteria, and, using NO donors, show that these elevated levels of NO are sufficient to induce cell death in Arabidopsis cells independently of reactive oxygen species (ROS). We also provide evidence that NO-induced cell death is a form of programmed cell death (PCD), requiring gene expression, and has a number of characteristics of PCD of mammalian cells: NO induced chromatin condensation and caspase-like activity in Arabidopsis cells, while the caspase-1 inhibitor, Ac-YVAD-CMK, blocked NO-induced cell death. A well-established second messenger mediating NO responses in mammalian cells is cGMP, produced by the enzyme guanylate cyclase. A specific inhibitor of guanylate cyclase blocked NO-induced cell death in Arabidopsis cells, and this inhibition was reversed by the cell-permeable cGMP analogue, 8Br-cGMP, although 8Br-cGMP alone did not induce cell death or potentiate NO-induced cell death. This suggests that cGMP synthesis is required but not sufficient for NO-induced cell death in Arabidopsis. In-gel protein kinase assays showed that NO activates a potential mitogen-activated protein kinase (MAPK), although a specific inhibitor of mammalian MAPK activation, PD98059, which blocked H2O2-induced cell death, did not inhibit the effects of NO.