Manganese oxidation states in Gaeumannomyces-infested wheat rhizospheres probeb by micro-XANES spectroscopy
Manganese oxidation states in Gaeumannomyces-infested wheat rhizospheres probeb by micro-XANES spectroscopy
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通过微型 XANES 光谱法探测全甘酵母侵染的小麦根际中的锰氧化态
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
D. Huber
中科院分区：
文献类型：
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作者：
D. Schulze;T. Mccay;S. Sutton;D. Huber
小麦全蚀病是由小麦全蚀病菌Gaeumannomyces graminis var.小麦白粉病是世界上危害最大的小麦根部病害之一。据推测，该菌在入侵前通过催化根面和根周土壤中可溶性Mn2+氧化为不溶性Mn4+，从而降低了寄主的防御机制。第一次，这一假设的直接测试已经完成了使用微X射线吸收近边结构（XANES）光谱，以获得有关的空间分布的锰氧化态的小麦根和周围的活的琼脂感染G。禾谷变种三个月。锰在透明琼脂中仅以Mn2+形式存在，而在感染G.禾谷变种三氧化二锰主要以Mn4+形式存在。Mn氧化态的分布清楚地表明，在感染G.禾谷变种三个月。这是一致的锰浓度的地图，显示了相对积累的总锰在根的内部作为一个结果G。禾谷变种小麦催化的生物矿化鉴于X射线的穿透性，微XANES技术应适用于生长在土壤中的根，从而提供了一种技术，以测量锰氧化态发病过程中的条件下，密切模拟自然土壤环境。
The take-all disease, caused by Gaeumannomyces graminis var. tritici, is one of the world's most damaging root diseases of wheat. It has been hypothesized that the fungus reduces the host's defense mechanism prior to invasion by catalyzing the oxidation of soluble Mn 2+ to insoluble Mn 4+ on the rhizoplane and in the soil surrounding the root. For the first time, a direct test of this hypothesis has been accomplished using micro-X-ray absorption near edge structure (XANES) spectroscopy to obtain information about the spatial distribution of Mn oxidation states in and around live wheat roots growing in agar infected with G. graminis var. tritici. Mn in clear agar occurred only as Mn 2+ , whereas Mn around dark roots infected with G. graminis var. tritici was predominately present as Mn 4+ . The distribution of Mn oxidation states clearly showed the presence of Mn 4+ -containing precipitates in the interior of a root infected with G. graminis var. tritici. This was consistent with a map of Mn concentration that showed a relative accumulation of total Mn in the interior of the root as a result of G. graminis var. tritici-catalyzed biomineralization. Given the penetrating nature of X rays, the micro-XANES technique should be applicable to roots growing in soil, thus providing a technique to measure Mn oxidation states during pathogenesis under conditions that closely simulate the natural soil environment.