Flavins secreted by roots of iron-deficient Beta vulgaris enable mining of ferric oxide via reductive mechanisms.
Flavins secreted by roots of iron-deficient Beta vulgaris enable mining of ferric oxide via reductive mechanisms.
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DOI：
10.1111/nph.13633
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发表时间：
2016
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影响因子：
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通讯作者：
Patricia Sisó-Terraza;J. J. Ríos-J.;J. Abadía;A. Abadı́a;A. Álvarez-Fernández
中科院分区：
文献类型：
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作者：
Patricia Sisó-Terraza;J. J. Ríos-J.;J. Abadía;A. Abadı́a;A. Álvarez-Fernández
铁(Fe)在土壤中含量丰富，但一般很难溶解。植物，除禾本科外，利用铁(III)-螯合还原酶偶联到铁(II)转运体来吸收铁。非禾本科植物是否能将难溶的Fe(III)转化为可溶的Fe(III)，到目前为止还没有引起足够的重视。我们以甜菜为材料，研究黄素是否参与铁的获取，甜菜是缺铁时根分泌黄素的众多物种之一。从营养液中去除缺铁植物分泌的黄素，并与缺铁植物和不去除黄素的缺铁植物进行比较。在存在或不存在黄素、NADH(还原型烟酰胺腺嘌呤二核苷酸)或植物根以及Fe(II)捕捉剂的情况下，对难溶的Fe(III)-氧化物的增溶作用进行了评估。营养液中黄素的去除加剧了缺铁诱导的叶片失绿。在NADH存在下，黄素能溶解Fe(III)-氧化物。胞外黄素的加入能够使缺铁植物的根还原地溶解Fe(III)-氧化物。我们的结论是，根分泌的黄素改善了普通菜豆的铁营养。黄素通过还原机制从铁(III)-氧化物中提取铁。
Iron (Fe) is abundant in soils but generally poorly soluble. Plants, with the exception of Graminaceae, take up Fe using an Fe(III)-chelate reductase coupled to an Fe(II) transporter. Whether or not nongraminaceous species can convert scarcely soluble Fe(III) forms into soluble Fe forms has deserved little attention so far. We have used Beta vulgaris, one among the many species whose roots secrete flavins upon Fe deficiency, to study whether or not flavins are involved in Fe acquisition. Flavins secreted by Fe-deficient plants were removed from the nutrient solution, and plants were compared with Fe-sufficient plants and Fe-deficient plants without flavin removal. Solubilization of a scarcely soluble Fe(III)-oxide was assessed in the presence or absence of flavins, NADH (nicotinamide adenine dinucleotide, reduced form) or plant roots, and an Fe(II) trapping agent. The removal of flavins from the nutrient solution aggravated the Fe deficiency-induced leaf chlorosis. Flavins were able to dissolve an Fe(III)-oxide in the presence of NADH. The addition of extracellular flavins enabled roots of Fe-deficient plants to reductively dissolve an Fe(III)-oxide. We concluded that root-secretion of flavins improves Fe nutrition in B. vulgaris. Flavins allow B. vulgaris roots to mine Fe from Fe(III)-oxides via reductive mechanisms.