Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam-Golm, Germany.
Nature. 2011 Oct 23;479(7373):419-22. doi: 10.1038/nature10536.
The majority of eukaryotic organisms rely on molecular oxygen for respiratory energy production. When the supply of oxygen is compromised, a variety of acclimation responses are activated to reduce the detrimental effects of energy depletion. Various oxygen-sensing mechanisms have been described that are thought to trigger these responses, but they each seem to be kingdom specific and no sensing mechanism has been identified in plants until now. Here we show that one branch of the ubiquitin-dependent N-end rule pathway for protein degradation, which is active in both mammals and plants, functions as an oxygen-sensing mechanism in Arabidopsis thaliana. We identified a conserved amino-terminal amino acid sequence of the ethylene response factor (ERF)-transcription factor RAP2.12 to be dedicated to an oxygen-dependent sequence of post-translational modifications, which ultimately lead to degradation of RAP2.12 under aerobic conditions. When the oxygen concentration is low-as during flooding-RAP2.12 is released from the plasma membrane and accumulates in the nucleus to activate gene expression for hypoxia acclimation. Our discovery of an oxygen-sensing mechanism opens up new possibilities for improving flooding tolerance in crops.
大多数真核生物依赖分子氧来进行呼吸能量产生。当氧气供应受到影响时，会激活各种适应反应来减轻能量耗竭的有害影响。已经描述了各种氧感应机制，这些机制被认为会触发这些反应，但它们似乎都具有特定的生物领域特异性，并且直到现在才在植物中确定任何感应机制。在这里，我们表明，蛋白质降解的泛素依赖性 N 末端规则途径的一个分支在哺乳动物和植物中都很活跃，在拟南芥中作为一种氧感应机制发挥作用。我们鉴定出乙烯反应因子 (ERF)-转录因子 RAP2.12 的保守的氨基末端氨基酸序列专门用于一种依赖于氧的翻译后修饰序列，该序列最终导致 RAP2.12 在有氧条件下降解。当氧浓度较低（例如在洪水期间）时，RAP2.12 从质膜释放并积累在核内以激活低氧适应的基因表达。我们发现氧感应机制为提高作物的耐淹水能力开辟了新的可能性。
