Kalemba Ewa Marzena, Alipour Shirin, Wojciechowska Natalia
Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland.
Department of General Botany, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland.
Antioxidants (Basel). 2021 Dec 20;10(12):2021. doi: 10.3390/antiox10122021.
European beech is an important component of European lowland forests in terms of ecology, and produces irregular seeds categorized as intermediate due to their limited longevity. Removal of the excess of reactive oxygen species is crucial for redox homeostasis in growing plant tissues. Hydrogen peroxide (HO) is detoxified via the plant-specific ascorbate-glutathione cycle, and enzymatically, mainly by catalase (CAT). The reduced and oxidized (redox) forms of ascorbate (AsA, DHA) and glutathione (GSH, GSSG) decreased during maturation as the content of redox forms of nicotinamide adenine dinucleotide (NADH, NAD) phosphate (NADPH, NADP), cofactors of ascorbate-glutathione enzymes, declined and limited this cycle. The degree of oxidation of glutathione peaked at approximately 80%, at the exact time when the NADP content was the lowest and the NADPH/NADP ratio reached the highest values. The glutathione pool was reflected in changes in the NADP pool, both in embryonic axes (R = 0.61) and in cotyledons (R = 0.98). A large excess of NADPH was reported in embryonic axes, whereas cotyledons displayed more unified levels of NADP redox forms. As a result, anabolic redox charge and reducing power were higher in embryonic axes. CAT was recognized as two proteins, and the abundance of the 55 kDa protein was correlated with all redox forms of ascorbate, glutathione, NAD, and NADP, whereas the 37 kDa protein was oppositely regulated in embryonic axes and cotyledons. Here, we discuss the role of NAD(P) in the regulation of the ascorbate-glutathione cycle, catalase, and seed longevity concerning a putative role of NAD(P)H as a redox biomarker involved in predefining seed quality, because NAD(P)H-derived redox homeostasis was found to be better controlled in embryonic axes than cotyledons.
从生态学角度来看，欧洲山毛榉是欧洲低地森林的重要组成部分，其产生的种子不规则，由于寿命有限而被归类为中间型种子。清除过量的活性氧对于生长中的植物组织的氧化还原稳态至关重要。过氧化氢（H₂O₂）通过植物特有的抗坏血酸-谷胱甘肽循环进行解毒，主要通过过氧化氢酶（CAT）进行酶促解毒。随着烟酰胺腺嘌呤二核苷酸（NADH、NAD）磷酸（NADPH、NADP）（抗坏血酸-谷胱甘肽酶的辅因子）的氧化还原形式含量下降并限制了这个循环，抗坏血酸（AsA、DHA）和谷胱甘肽（GSH、GSSG）的还原态和氧化态（氧化还原态）在种子成熟过程中降低。谷胱甘肽的氧化程度在大约80%时达到峰值，此时NADP含量最低，NADPH/NADP比值达到最高值。谷胱甘肽库反映在NADP库的变化中，在胚轴（R = 0.61）和子叶（R = 0.98）中均如此。胚轴中报告有大量过量的NADPH，而子叶中NADP氧化还原形式的水平更为统一。因此，胚轴中的合成代谢氧化还原电荷和还原能力更高。CAT被识别为两种蛋白质，55 kDa蛋白质的丰度与抗坏血酸、谷胱甘肽、NAD和NADP的所有氧化还原形式相关，而37 kDa蛋白质在胚轴和子叶中受到相反的调节。在这里，我们讨论了NAD(P)在抗坏血酸-谷胱甘肽循环、过氧化氢酶和种子寿命调节中的作用，涉及NAD(P)H作为参与预先确定种子质量的氧化还原生物标志物的假定作用，因为发现胚轴中NAD(P)H衍生的氧化还原稳态比子叶中得到更好的控制。
