An aluminum-resistance mechanism in Eucalyptus camaldulensis: complexation between aluminum and oenothein B in presence of organic acids in vitro
An aluminum-resistance mechanism in Eucalyptus camaldulensis: complexation between aluminum and oenothein B in presence of organic acids in vitro
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DOI：
10.1080/13416979.2017.1326656
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发表时间：
2017-01-01
影响因子：
1.5
通讯作者：
Shinohara, Kenji
中科院分区：
文献类型：
--
作者：
Tahara, Ko;Hiradate, Syuntaro;Shinohara, Kenji
近年来，在赤桉（Eucalyptus camaldulensis）中发现了一种可水解的单宁--月见草黄素（oenothein）B，它是一种新型的铝结合解毒配体。月见草肽B主要定位于根共质体中，其中也存在已知的配体柠檬酸盐和草酸盐。在这项研究中，为了研究在柠檬酸盐和草酸盐存在下，月见草碱B是否可以与Al形成复合物，我们在体外分析了含有Al、月见草碱B、柠檬酸盐和草酸盐的多配体混合物中Al的化学形式，其浓度模拟了大肠杆菌共质体中的那些. Camaldulensis根在混合物中，27%的总铝中检测到的不溶性馏分，和28%的高分子量（> 10 kDa）的可溶性馏分。这意味着混合物中一半以上的Al与月见草素B发生相互作用，因为在三种配体中，只有月见草素B主要与Al形成不溶或高分子量可溶性复合物。混合物的Al-27-核磁共振分析表明，低分子量可溶性Al并非主要由简单的Al-柠檬酸盐或Al-草酸盐复合物组成。这些结果支持了我们的假设，即oenothein B有助于在E. Camaldulensis根
A hydrolyzable tannin, oenothein B, has recently been identified as a novel type of Al-binding and detoxifying ligand in a highly aluminum (Al)-resistant tree, Eucalyptus camaldulensis. Oenothein B is mainly localized in the root symplast, where the known ligands, citrate and oxalate, are also present. In this study, to investigate whether oenothein B can form complexes with Al in the presence of citrate and oxalate, we analyzed the chemical form of Al in multiple - ligand mixtures containing Al, oenothein B, citrate, and oxalate in vitro at concentrations mimicking those in the symplast of E. camaldulensis roots. In the mixture, 27% of total Al was detected in the insoluble fraction, and 28% in the high-molecular mass (> 10 kDa) soluble fraction. This means that more than half of Al in the mixture interacts with oenothein B, because among the three ligands only oenothein B can predominantly form insoluble or high molecular mass soluble complexes with Al. The Al-27-nuclear magnetic resonance analyses of the mixture showed that low-molecular mass soluble Al was not mainly composed of simple Al-citrate or Al-oxalate complexes. These results support our hypothesis that oenothein B contributes to internal detoxification of Al in the symplast of E. camaldulensis roots.