Nitrogen fixation control in Herbaspirillum seropedicae
Nitrogen fixation control in Herbaspirillum seropedicae
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DOI：
10.1007/s11104-011-0819-6
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发表时间：
2012-07-01
期刊：
影响因子：
4.9
通讯作者：
Pedrosa, Fabio de Oliveira
中科院分区：
文献类型：
--
作者：
Chubatsu, Leda Satie;Monteiro, Rose Adele;Pedrosa, Fabio de Oliveira
Herbaspirillum seropedicae是一种革兰氏阴性内生固氮菌，与重要的农作物相关。几项研究表明，这种生物可以促进植物生长，这表明它有可能用作生物肥料。H.血清学在转录和翻译后水平都受到高度调控。这两种调节水平都通过相互作用蛋白质的级联反应来响应外部介质中的铵可用性。该过程的转录调节也响应于氧，其可能由转录调节因子NifA直接感知。本文综述了近年来有关H.血清学信号转导蛋白GlnK在转录和翻译后水平上都是固氮的关键调节因子。体外分析表明GlnK与NifA相互作用并可能调节其活性，从而控制nif表达。GlnK，连同铵通道蛋白AmtB，也参与固氮酶活性的翻译后调节的一个未知的机制。该调节系统根据H.血清学
Herbaspirillum seropedicae is a Gram-negative endophytic diazotroph that associates with important agricultural crops. Several studies have shown that this organism can contribute to plant growth suggesting potential for use as a biofertilizer. Nitrogen fixation in H. seropedicae is highly regulated both at the transcriptional and post-translational levels. Both of these regulatory levels respond to the ammonium availability in the external medium through a cascade of interacting proteins. The transcriptional regulation of the process also responds to oxygen, which is probably directly sensed by the transcriptional regulator NifA. Here, we review current knowledge of the regulation of nitrogen fixation in H. seropedicae. The signal transduction protein GlnK is a key regulator of nitrogen fixation at both the transcriptional and post-translational levels. In vitro analysis indicates that GlnK interacts with NifA and probably modulates its activity, thereby controlling nif expression. GlnK, together with the ammonium channel protein AmtB, also participates in the post-translational regulation of nitrogenase activity by an unidentified mechanism. This regulatory system efficiently controls nitrogen fixation according to prevailing fixed nitrogen and oxygen levels in H. seropedicae.