Cellular dissolution at hypha- and spore-mineral interfaces revealing unrecognized mechanisms and scales of fungal weathering
Cellular dissolution at hypha- and spore-mineral interfaces revealing unrecognized mechanisms and scales of fungal weathering
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DOI：
10.1130/g37561.1
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发表时间：
2016-04-01
期刊：
影响因子：
5.8
通讯作者：
Teng, H. Henry
中科院分区：
文献类型：
--
作者：
Li, Zibo;Liu, Lianwen;Teng, H. Henry
真菌与矿物质的相互作用在塑造地球方面发挥着无与伦比的作用，但相对于细菌的影响却被低估了。考虑到相关的膨压差以及关键区域中菌丝体和矿物质之间的巨大接触面积，菌丝与孢子-矿物质相互作用的界面过程和广泛性是真菌所独有的，但在很大程度上是未知的。在这里，我们使用共焦激光扫描显微镜、原子力显微镜和透射电子显微镜-能量色散 X 射线光谱检查天然真菌菌株单细胞对蜥蜴石 [Mg3Si2O5(OH)(4)] 的溶解，以探索界面反应的机制、驱动力和强度。我们的检查结果显示（1）矿物质表面附着后细胞附近的 pH 值显着降低，（2）细胞-矿物质界面处的矿物质仅损失铁，（3）菌丝定殖区域下方的矿物晶体结构被破坏，但孢子定殖区域没有。与大量实验和矿泉水界面的结果相比，这些观察结果表明（1）只有附着细胞释放铁载体，（2）菌丝生长的生物力学力对于真菌风化是不可或缺的，并且足够强大以破坏矿物晶格。界面处估计的矿物质量损失表明，细胞溶解最终可占总体生物风化的 40%-50%，明显大于之前估计的约 1% 的贡献。
Fungus-mineral interactions play unparalleled roles in shaping the planet Earth but are underappreciated relative to bacterial influences. Unique to fungus, but largely unknown, are the interfacial processes and extensiveness of hypha-versus spore-mineral interactions given the associated turgor pressure differences and the vast contact areas between mycelia and minerals in the critical zone. Here we examine lizardite [Mg3Si2O5(OH)(4)] dissolution by single cells of a native fungal strain using confocal laser scanning microscopy, atomic force microscopy, and transmission electron microscopy-energy dispersive X-ray spectroscopy to explore the mechanism, driving force, and magnitude of the interfacial reactions. Results from our inspection showed (1) significant pH reduction in the vicinity of cells upon mineral surface attachment, (2) exclusive Fe loss from the mineral at the cell-mineral interfaces, and (3) destruction of the mineral crystal structure below the area colonized by hyphae but not that by spores. Compared to the results from bulk experiments and at the mineral-water interface, these observations indicate that (1) only attached cells release siderophores and (2) biomechanical forces of hyphal growth are indispensable for fungal weathering and strong enough to breach the mineral lattice. Estimated mineral mass loss at the interface suggests that cellular dissolution can ultimately account for similar to 40%-50% of the overall bio-weathering, significantly larger than the previous estimate of similar to 1% contribution.