Department of Biotechnology, Bioenergy Research Center, Interdisciplinary Program of Bioenergy and Biomaterials, Chonnam National University, Gwangju, South Korea.
J Pineal Res. 2012 Aug;53(1):107-11. doi: 10.1111/j.1600-079X.2012.00976.x. Epub 2012 Jan 31.
The effect of light on melatonin biosynthesis was examined in detached rice (Oryza sativa cv. Asahi) leaves during the senescence process. The detached leaves were exposed to senescence treatment either in constant darkness or in constant light, and subjected to HPLC analysis for melatonin and its precursors. Higher melatonin levels were detected in rice leaves under constant light while very low levels were observed in constant darkness. Levels of the melatonin intermediates, tryptamine, serotonin, and N-acetylserotonin significantly decreased in the dark compared to those in the light. Furthermore, relative mRNA levels of melatonin biosynthetic genes and their corresponding proteins decreased accordingly in constant darkness. The most striking difference between constant light and dark was observed in levels of the protein tryptamine 5-hydroxylase. These results suggest that melatonin biosynthesis during senescence is dependent on light signals in rice leaves, contrary to the response found in animals.
在衰老过程中，研究了光对离体水稻（Oryza sativa cv. Asahi）叶片中天冬氨酸合成的影响。将离体叶片分别置于持续黑暗或持续光照下进行衰老处理，并通过 HPLC 分析检测褪黑素及其前体。结果表明，在持续光照下，水稻叶片中的褪黑素水平较高，而在持续黑暗中则非常低。与光照相比，黑暗中褪黑素中间体色胺、血清素和 N-乙酰血清素的水平显著降低。此外，在持续黑暗中，褪黑素生物合成基因及其相应蛋白质的相对 mRNA 水平相应降低。在持续光照和黑暗之间最显著的差异是色氨酸 5-羟化酶蛋白水平。这些结果表明，与动物的反应相反，在水稻叶片衰老过程中，褪黑素的生物合成依赖于光信号。
