Nitrate Reductase Modulation in Response to Changes in C/N Balance and Nitrogen Source in Arabidopsis
Nitrate Reductase Modulation in Response to Changes in C/N Balance and Nitrogen Source in Arabidopsis
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DOI：
10.1093/pcp/pcy065
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发表时间：
2018-06
影响因子：
4.9
通讯作者：
Thais Huarancca Reyes;A. Scartazza;A. Pompeiano;A. Ciurli;Yu Lu;L. Guglielminetti;J. Yamaguchi
中科院分区：
文献类型：
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作者：
Thais Huarancca Reyes;A. Scartazza;A. Pompeiano;A. Ciurli;Yu Lu;L. Guglielminetti;J. Yamaguchi
环境因子调节植物代谢和生长所必需的碳（C）和氮（N）的平衡。在拟南芥中，不平衡的C/N比影响PSII的光化学效率、许多酶的磷酸化状态和定位以及总可溶性糖的水平。由于C/N的差异会影响这些参数，因此我们检查了当施加高C/N比时，不同的N源是否具有不同的影响。在C/N培养基中分别提供NO3-和NH 4+。研究了C/N胁迫条件下与对照相比，对水稻叶片PSII光化学效率、可溶性总糖含量和硝酸还原酶活性的影响。我们发现，处理过的植物积累更多的总可溶性糖相比，控制。24 h后，两种氮源的PSII光化学效率差异不显著。实际硝酸还原酶活性是活性、活化状态和蛋白质水平的组合的结果。在对照条件下，该活性从时间0开始不断下降;相反，实际硝酸还原酶活性在用NO3-处理后2 h和用NH 4+处理后30 min显示出峰值。根据总可溶性糖的水平，这可以通过培养基中过量的糖和低硝酸盐之间存在的串扰来解释，该串扰在胁迫糖条件下阻断硝酸还原酶的活性，直到植物适应胁迫。
Environmental cues modulate the balance of carbon (C) and nitrogen (N) which are essential elements for plant metabolism and growth. In Arabidopsis, photochemical efficiency of PSII, phosphorylation status and localization of many enzymes, and the level of total soluble sugars were affected by an unbalanced C/N ratio. Since differences in C/N affect these parameters, here we checked whether different sources of N have different effects when a high C/N ratio is imposed. NO3- and NH4+ were separately provided in C/N medium. We investigated the effects on photochemical efficiency of PSII, the level of total soluble sugars and nitrate reductase activity under stressful C/N conditions compared with control conditions. We found that treated plants accumulated more total soluble sugars when compared with control. Photochemical efficiency of PSII did not show significant differences between the two sources of nitrogen after 24 h. The actual nitrate reductase activity was the result of a combination of activity, activation state and protein level. This activity constantly decreased starting from time zero in control conditions; in contrast, the actual nitrate reductase activity showed a peak at 2 h after treatment with NO3-, and at 30 min with NH4+. This, according to the level of total soluble sugars, can be explained by the existence of a cross-talk between the sugars in excess and low nitrate in the medium that blocks the activity of nitrate reductase in stressful sugar conditions until the plant is adapted to the stress.