Institute of Microbiology, Friedrich Schiller University, Neugasse 25, 07743 Jena, Germany.
Institute of Geosciences, Applied Geology, Friedrich Schiller University, Burgweg 11, 07749 Jena, Germany.
J Hazard Mater. 2022 Mar 5;425:127978. doi: 10.1016/j.jhazmat.2021.127978. Epub 2021 Dec 3.
Fungi living in heavy metals and radionuclides contaminated environments, namely the Chernobyl Exclusion Zone need to be able to cope with these pollutants. In this study, the wood-rot fungus Schizophyllum commune was investigated for its metal tolerance mechanisms, and for its ability to transport such metals through its hyphae. Effects of temperature and pH on tolerance of Cs, Sr, Cd, and Zn were tested. At concentrations allowing for half-maximal growth, adapted strains were raised. The strontium-adapted strain, S. commune 12-43 Sr, showed transport of specifically Sr over distances on a cm-scale using split plates. The adaptation did not yield changes in cell or colony morphology. Intracellular metal localization was not changed, and gene expression profiles under metal stress growing on soil versus artificial medium showed a higher impact of a structured surface for growth on soil than with different metal concentrations. In the transcriptome, transporter genes were mostly down-regulated, while up-regulation was seen for genes involved in the secretory pathway under metal stress. A comparison of wildtype and adapted strains could confirm lower cellular stress levels leading to lack of glutathione S-transferase up-regulation in the adapted strain. Thus, we could show metal transport as well as specific mechanisms in metal stress avoidance.
生活在重金属和放射性核素污染环境中的真菌，即切尔诺贝利隔离区，需要能够应对这些污染物。在这项研究中，研究了木材腐朽真菌裂褶菌（Schizophyllum commune）的金属耐受机制及其通过菌丝运输这些金属的能力。测试了温度和 pH 值对 Cs、Sr、Cd 和 Zn 耐受性的影响。在允许半最大生长的浓度下，培养了适应菌株。适应 Sr 的菌株 S. commune 12-43 Sr 在使用分裂平板的情况下，能够在厘米级的距离上特异性地运输 Sr。适应并没有改变细胞或菌落形态。细胞内金属定位没有改变，在土壤与人工培养基上生长时，金属胁迫下的基因表达谱显示，与不同的金属浓度相比，结构化表面对生长的影响更大。在转录组中，转运蛋白基因大多下调，而在金属胁迫下，与分泌途径相关的基因则上调。野生型和适应型菌株的比较可以证实适应型菌株中细胞应激水平较低，导致谷胱甘肽 S-转移酶上调缺失。因此，我们可以证明金属运输以及金属应激回避中的特定机制。
