Response of soil fungal communities to long-term soil mercury pollution

Mercury naturally occurs in soil and can accumulate in high concentrations because of various human activities. In order to further explore the effect of long-term mercury contamination of soil near a mercury mining area (Tongren, Guizhou Province, China) on soil fungal communities. Soil samples (mercury content: SMO20 > SMO2 > SMO650 > SMO30 > SMO500) were collected from five locations at distances of 2 m, 20 m, 30 m, 500 m, and 650 m, respectively, from the only sewage outlet of a mercury mining area (Guizhou, China). The soil microbial DNA was extracted from each soil sample and sequenced via high-throughput sequencing technology. The sequencing results indicated that, at both the phylum and class levels, the soil fungal community diversity of SMO2 and SMO30 was greater than that of SMO20, SMO500, and SMO650. The soil fungal community structure analysis revealed common and unique dominant fungal communities within the soil sample groups at both the phylum and class levels. Redundancy analysis (RDA) of relationships between soil fungal community structure and soil environmental factors (pH, EC, available N, P, K, and mercury content) revealed that mercury was the most influential factor. The survival of high-abundance fungal community taxa is strong evidence of the fungal community's high adaptability to long-term soil mercury contamination. The results of this study provide a scientific basis for further studies on the mechanism of mercury tolerance in soil fungi under long-term mercury stress.