Fig. 6

Genomic analysis of viral genomes in Cr-contaminated soils. A The relative abundance of viral genes coding membrane transporter (dark blue) and reductase (gray) were annotated by KEGG datasets (Table S3 and Table S4). There was a significant increase in the relative abundance of these genes associated with reduction and transport of heavy metals in L3 and Z2. B The distribution ratio of genes coding reductase (left) and membrane transporter (right) on lysogenic phages (blue) and other viruses (green), which were are calculated by determining whether these genes are carried by viral contigs with the integrase genes. It shows that over 60% of them were on lysogenic phages, so lysogenic phages are an important reservoir for MRGs. C Genome map of four viral contigs containing both the phage integrase gene and the metal detoxification gene. Key of gene families and their colors are found in the figure, and arrow length within the gene maps correspond to the size of the open reading frame (ORF). Detailed function descriptions of the seven viral contigs are listed in Table S5