Effect of temperature on the Arabidopsis cryptochrome photocycle
Effect of temperature on the Arabidopsis cryptochrome photocycle
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DOI：
10.1111/ppl.13365
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发表时间：
2021-03-01
影响因子：
6.4
通讯作者：
Ahmad, Margaret
中科院分区：
文献类型：
--
作者：
Pooam, Marootpong;Dixon, Nykiera;Ahmad, Margaret
隐花色素是在植物和动物中发现的具有许多重要信号功能的蓝光吸收光感受器。这些包括控制植物生长、发育和昼夜节律钟。植物隐花色素最近被牵连在适应温度变化，包括昼夜节律钟的温度补偿。然而，温度对隐花色素感光体的光化学性质的直接影响仍然未知。在这里，我们表明，响应光的纯化的拟南芥Cry 1和Cry 2蛋白的温度显着改变。光谱分析表明，在15摄氏度的显着降低黄素再氧化率从生物活性，光诱导（FADH度）信号状态的隐花色素的非活性（FADox）休息氧化还原状态相比，环境温度（25摄氏度）。这一结果表明，在低温下，Cry的生物活性FADH度氧化还原形式的浓度增加，导致违反直觉的预测，即在较低温度下Cry的生物活性应该增加。使用Cry 1隐花色素C-末端磷酸化作为体内Cry激活的直接生物测定证实了这一点。我们的结论是，增强隐花色素功能在体内低温下是一致的隐花色素光循环的温度调制。
Cryptochromes are blue light-absorbing photoreceptors found in plants and animals with many important signalling functions. These include control of plant growth, development, and the entrainment of the circadian clock. Plant cryptochromes have recently been implicated in adaptations to temperature variation, including temperature compensation of the circadian clock. However, the effect of temperature directly on the photochemical properties of the cryptochrome photoreceptor remains unknown. Here we show that the response to light of purified Arabidopsis Cry1 and Cry2 proteins was significantly altered by temperature. Spectral analysis at 15 degrees C showed a pronounced decrease in flavin reoxidation rates from the biologically active, light-induced (FADH degrees) signalling state of cryptochrome to the inactive (FADox) resting redox state as compared to ambient (25 degrees C) temperature. This result indicates that at low temperatures, the concentration of the biologically active FADH degrees redox form of Cry is increased, leading to the counterintuitive prediction that there should be an increased biological activity of Cry at lower temperatures. This was confirmed using Cry1 cryptochrome C-terminal phosphorylation as a direct biological assay for Cry activation in vivo. We conclude that enhanced cryptochrome function in vivo at low temperature is consistent with modulation by temperature of the cryptochrome photocycle.