Cytokinins can act as suppressors of nitric oxide in Arabidopsis
Cytokinins can act as suppressors of nitric oxide in Arabidopsis
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细胞分裂素可以作为拟南芥中一氧化氮的抑制剂
DOI：
10.1073/pnas.1213235110
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发表时间：
2013-01-22
影响因子：
11.1
通讯作者：
He, Yi-Kun
中科院分区：
文献类型：
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作者：
Liu, Wei-Zhong;Kong, Dong-Dong;He, Yi-Kun
维持一氧化氮 (NO) 稳态对于正常植物生理过程至关重要。然而，人们对植物中 NO 的调节机制知之甚少。在这里，我们报告了一种基于与植物激素细胞分裂素反应的一氧化氮分解代谢的独特机制。我们在拟南芥中筛选了 NO 不敏感突变体，并分离了两个等位基因系：cnu1-1 和 1-2（连续 NO 无应激 1），它们被鉴定为先前报道的改变的分生组织程序 1 (amp1)，并且细胞分裂素水平升高。 cnu1-2 和一氧化氮过表达 1 (nox1) 的双突变体降低了由于 NO 水平过高而导致的表型的严重程度，就像用反式玉米素（拟南芥中细胞分裂素的主要形式）处理 nox1 系一样。我们进一步表明，过氧亚硝酸盐（一种活性NO衍生物）可以在体外与玉米素发生反应，这与体内结果一起表明细胞分裂素很可能通过它们之间的直接相互作用抑制NO的作用，从而导致内源性NO水平降低。这些结果为植物中 NO 信号传导及其生物活性的调节提供了见解。
Maintaining nitric oxide (NO) homeostasis is essential for normal plant physiological processes. However, very little is known about the mechanisms of NO modulation in plants. Here, we report a unique mechanism for the catabolism of NO based on the reaction with the plant hormone cytokinin. We screened for NO-insensitive mutants in Arabidopsis and isolated two allelic lines, cnu1-1 and 1–2 (continuous NO-unstressed 1), that were identified as the previously reported altered meristem program 1 (amp1) and as having elevated levels of cytokinins. A double mutant of cnu1-2 and nitric oxide overexpression 1 (nox1) reduced the severity of the phenotypes ascribed to excess NO levels as did treating the nox1 line with trans-zeatin, the predominant form of cytokinin in Arabidopsis. We further showed that peroxinitrite, an active NO derivative, can react with zeatin in vitro, which together with the results in vivo suggests that cytokinins suppress the action of NO most likely through direct interaction between them, leading to the reduction of endogenous NO levels. These results provide insights into NO signaling and regulation of its bioactivity in plants.