Fig. 4: The proposed metabolic pathways associated with methylmercury (CH₃Hg⁺) degradation by soil microorganisms.

A The potential metabolic pathways linked with CH₃Hg⁺ degradation at the community level from the high Hg-contaminated paddy soil based on the predicted genes. B Heatmaps of the genes involved in Hg reduction and metabolisms of carbon, methane and nitrogen detected in the CH₃Hg⁺ degraders associated MAGs recovered from the ¹³CH₃Hg⁺ treatment. The color gradient in (A) represents the relative abundances of major genes of metagenomic analysis in the heavy DNA fraction from the ¹³CH₃Hg⁺ treatment and the corresponding fraction in the ¹²CH₃Hg⁺ treatment. The square and circle in (A) represent genes in the ¹²CH₃Hg⁺ and ¹³CH₃Hg⁺ treatments, respectively. The definitions of genes are listed in the Source data. * indicates genes that exhibited significant enrichment in the heavy fraction of the ¹³C-labeled treatment compared to the corresponding fraction in the ¹²C control at levels of p < 0.05 based on two-sided T Test. The colors in (B) indicate the number of the gene(s) detected in the MAGs. Exact p-values and Source data are provided as a Source Data file. Figure 4A was created in BioRender (https://BioRender.com/oksd9hf).