Regulation of Sugar and Storage Oil Metabolism by Phytochrome during De-etiolation
Regulation of Sugar and Storage Oil Metabolism by Phytochrome during De-etiolation
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DOI：
10.1104/pp.19.00535
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发表时间：
2020-02-01
期刊：
影响因子：
7.4
通讯作者：
Nagatani, Akira
中科院分区：
文献类型：
--
作者：
Kozuka, Toshiaki;Sawada, Yuji;Nagatani, Akira
黑暗生长（黄化）的幼苗暴露于光诱导的异养到光自养的过渡（去黄化）过程，包括在叶绿体和子叶扩张的光合机制的形成。光敏色素是红（R）/远红光（FR）光受体，其参与去黄化的各个方面。然而，光敏色素如何调节代谢动力学响应光刺激仍然是未知的。在这项研究中，阐明参与的光敏色素在代谢反应过程中去黄化，我们进行了广泛的目标代谢组学在拟南芥（拟南芥）野生型和光敏色素A和B双突变体幼苗去黄化下的R或FR光。结果表明，光敏色素在去黄化的前24 h内对叶片的初级代谢和次级代谢有强烈的影响。在这些代谢产物中，糖水平在去黄化过程中以光敏色素依赖性方式降低。与此同时，光敏色素上调了需要糖的过程。在拟南芥幼苗中，三酰甘油作为糖的来源储存在油体中。糖由三酰基甘油通过脂肪酸β-氧化和乙醛酸酶体中的乙醛酸循环提供。我们研究了光敏色素是否以及如何调节油体的糖生产。照射黄化幼苗与R和FR光显着加速油体动员光敏色素依赖的方式。乙醛酸循环缺陷型突变体不仅不能动员油体，而且在光照下也不能形成类囊体膜和扩大子叶细胞。因此，光敏色素在去黄化过程中的代谢调节中起着关键作用。
Exposure of dark-grown (etiolated) seedlings to light induces the heterotrophic-to-photoautotrophic transition (de-etiolation) processes, including the formation of photosynthetic machinery in the chloroplast and cotyledon expansion. Phytochrome is a red (R)/far-red (FR) light photoreceptor that is involved in the various aspects of de-etiolation. However, how phytochrome regulates metabolic dynamics in response to light stimulus has remained largely unknown. In this study, to elucidate the involvement of phytochrome in the metabolic response during de-etiolation, we performed widely targeted metabolomics in Arabidopsis (Arabidopsis thaliana) wild-type and phytochrome A and B double mutant seedlings de-etiolated under R or FR light. The results revealed that phytochrome had strong impacts on the primary and secondary metabolism during the first 24 h of de-etiolation. Among those metabolites, sugar levels decreased during de-etiolation in a phytochrome-dependent manner. At the same time, phytochrome upregulated processes requiring sugars. Triacylglycerols are stored in the oil bodies as a source of sugars in Arabidopsis seedlings. Sugars are provided from triacylglycerols through fatty acid beta-oxidation and the glyoxylate cycle in glyoxysomes. We examined if and how phytochrome regulates sugar production from oil bodies. Irradiation of the etiolated seedlings with R and FR light dramatically accelerated oil body mobilization in a phytochrome-dependent manner. Glyoxylate cycle-deficient mutants not only failed to mobilize oil bodies but also failed to develop thylakoid membranes and expand cotyledon cells upon exposure to light. Hence, phytochrome plays a key role in the regulation of metabolism during de-etiolation.