Magnetic sensitivity mediated by the Arabidopsis blue-light receptor cryptochrome occurs during flavin reoxidation in the dark
Magnetic sensitivity mediated by the Arabidopsis blue-light receptor cryptochrome occurs during flavin reoxidation in the dark
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DOI：
10.1007/s00425-018-3002-y
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发表时间：
2019-02-01
期刊：
影响因子：
4.3
通讯作者：
Ahmad, Margaret
中科院分区：
文献类型：
--
作者：
Pooam, Marootpong;Arthaut, Louis-David;Ahmad, Margaret
结论拟南芥隐色素介导了在无光条件下对磁场的响应，与黄素再氧化作为主要检测机制一致。隐色素是一种高度保守的蓝光吸收蛋白，与许多生物对电磁刺激的感知有关。其中包括让候鸟感知地球磁场的方向，以及让昆虫和植物感知磁场的强度。当暴露在光下时，隐花色素经历黄素还原/再氧化氧化还原循环，导致生物活化，产生被认为是磁敏感性基础的自由基对。然而，磁敏感自由基对的性质和它们在隐花色素氧化还原循环中的作用步骤目前是一个有争议的问题。在这里，我们研究了拟南芥隐色素-1在体内对500T（10倍地球磁场）静态磁场的响应，同时使用植物生长和光依赖性磷酸化作为实验。磁场增强了隐花色素对光的响应，表明下胚轴伸长的抑制增加，隐花色素磷酸化增加。然而，当光照和黑暗间隔间歇性地给予时，即使在光照之间的黑暗间隔中只给予磁场，也可以观察到植物对磁场的反应。这表明隐花色素光循环中的磁敏反应步骤必须发生在黄素再氧化过程中，并且可能涉及活性氧的形成。
Main conclusionArabidopsis cryptochrome mediates responses to magnetic fields that have been applied in the absence of light, consistent with flavin reoxidation as the primary detection mechanism.AbstractCryptochromes are highly conserved blue-light-absorbing flavoproteins which have been linked to the perception of electromagnetic stimuli in numerous organisms. These include sensing the direction of the earth's magnetic field in migratory birds and the intensity of magnetic fields in insects and plants. When exposed to light, cryptochromes undergo flavin reduction/reoxidation redox cycles leading to biological activation which generate radical pairs thought to be the basis for magnetic sensitivity. However, the nature of the magnetically sensitive radical pairs and the steps at which they act during the cryptochrome redox cycle are currently a matter of debate. Here, we investigate the response of Arabidopsis cryptochrome-1 in vivo to a static magnetic field of 500T (10xearth's field) using both plant growth and light-dependent phosphorylation as an assay. Cryptochrome responses to light were enhanced by the magnetic field, as indicated by increased inhibition of hypocotyl elongation and increased cryptochrome phosphorylation. However, when light and dark intervals were given intermittently, a plant response to the magnetic field was observed even when the magnetic field was given exclusively during the dark intervals between light exposures. This indicates that the magnetically sensitive reaction step in the cryptochrome photocycle must occur during flavin reoxidation, and likely involves the formation of reactive oxygen species.