Fungus-initiated catalytic reactions at hyphal-mineral interfaces drive iron redox cycling and biomineralization
Fungus-initiated catalytic reactions at hyphal-mineral interfaces drive iron redox cycling and biomineralization
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DOI：
10.1016/j.gca.2019.06.029
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发表时间：
2019-07
影响因子：
5
通讯作者：
Guanghui Yu;Zhilai Chi;H. Henry Teng;Haiquan Dong;A. Kappler;M. R. Gillings;M. Polizzotto;
中科院分区：
文献类型：
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作者：
Guanghui Yu;Zhilai Chi;H. Henry Teng;Haiquan Dong;A. Kappler;M. R. Gillings;M. Polizzotto;
真菌对各种矿物质的耐受能力影响植物营养，并增强了生命必需元素的全球生物地球化学循环。真菌-矿物界面在风化过程中起着关键作用，但这些过程背后的具体机制仍然知之甚少。在这里，我们用赤铁矿和贵州木霉研究了真菌-矿物风化作用。我们发现，随着培养时间的推移，赤铁矿的溶解增加，培养66小时后，在界面处形成的次生矿物高达3000 µm− 2。与菌丝有关的赤铁矿中，约15%转化为次生矿物水铁矿。重要的是，超氧自由基检测在菌丝尖端和沿着整个菌丝。在培养过程中，还检测到高浓度（约1000 nM）的羟基自由基。同步辐射光谱显微镜在真菌矿物界面表明，真菌菌丝改变当地的铁氧化还原状态，因此是氧化还原活性。这些研究结果表明，真菌引发的催化反应发生在菌丝-矿物界面，鉴于超氧化物不会扩散远离形成的网站。此外，这些结果也表明，催化反应可能作为一种新的策略，微生物铁的吸收。总之，这些发现构成了理解真菌使矿物质可用于生物系统的方式的重要一步。
The ability of fungi to weather a wide range of minerals influences plant nutrition and enhances global biogeochemical cycles of life-essential elements. The fungus-mineral interface plays a key role in weathering, but the specific mechanisms underlying these processes remain poorly understood. Here, we examined fungal-mineral weathering using hematite andTrichoderma guizhouense.We showed that hematite dissolution increased over cultivation time, with the formation of secondary minerals up to ∼3000 µm−2at the interfaces after 66 h cultivation. Of the hematite associated with hyphae, approximately 15% was converted to the secondary mineral ferrihydrite. Importantly, superoxide radicals were detected at the hyphal tips and along the whole hyphae. During cultivation, a high concentration (∼1000 nM) of hydroxyl radical was also detected. Synchrotron radiation based spectromicroscopies at fungus-mineral interfaces suggest that fungus hyphae alter the local redox state of iron and thus are redox-active. These findings indicate that fungus-initiated catalytic reactions occur at hyphal-mineral interfaces, in view of the fact that superoxide does not diffuse far from the site of formation. Furthermore, these results also suggest that the catalytic reactions may serve as a new strategy for microbial iron uptake. Together, these findings constitute a significant step forward in understanding the ways that fungi make minerals available to biological systems.