Effects of cadmium pollution on fungal community structure and diversity in paddy field

【Objective】To investigate the effects of cadmium stress on soil fungal community structure and diversity in paddy fields, so as to provide scientific basis for explaining the effect of mechanism of cadmium stress on paddy soil microbial diversity.【Method】Soil samples with 3 levels of cadmium pollution(high, medium and low) collected from paddy fields with around a cadmium mine in Hunan province were taken as research object, and soil nutrient contents were measured. Soil fungal community structure was explored through Illumina MiSeq high-throughput sequencing technology to analyze the difference of soil fungal community diversity and structure.【Result】The results showed that the fungal α diversity of rice soils decreased with the increase of Cd pollution level. The α diversity in high Cd group(total cadmium content>3.0 mg/kg) was significantly lower than that in medium Cd(total cadmium content:0.3-3.0 mg/kg) and low Cd (total cadmium content <3.0 mg/kg) groups(P<0.05, the same below), but there was a slight difference between medium and low Cd groups(P>0.05). There were significant differences in fungal communities among high Cd group, medium Cd group and low Cd group. At the phylum level, Ascomycota, Basidiomycota and Mortierellomycota were dominant phyla in all sample groups, with relative abundance ranging from 51.09% to 81.93%. Relative abundance of Hypholoma, Talaromyces and Meliniomyces in the high Cd group was significantly higher than that in the medium and low Cd groups, and they may be cadmium-resistant microbes. Organic matter, pH, alkaline N, available P, available K, total P, total Cd and available Cd were extremely significantly positively correlated with soil fungal community structure(P<0.01).【Conclusion】High concentrations of cadmium pollution can reduce α diversity of soil fungal community and change soil fungal community in paddy field. pH, alkaline N, available P, available K, total P, organic matter, total Cd and available Cd are significantly correlated with soil fungal community structure, which is the main factor affecting soil fungal community structure.