Fig. 7

Nitrogen metabolism in the gut of termites. A Metagenome-assembled genomes (MAGs) with complete nitrogen fixation or dissimilatory nitrate reduction pathways. All pathways potentially involved in the nitrogen metabolism, namely nitrogen fixation, dissimilatory nitrate reduction, ureases, glutamate metabolism, ammonia transport, urea transport, and arginine metabolism are represented. The tree represents a simplified maximum likelihood phylogenetic tree of the MAGs inferred from 43 marker genes. Completeness and contamination of MAGs, based on CheckM analysis, are shown beside the tree. Dark blue squares indicate gene presence, light blue squares indicate incomplete gene sets, and open squares indicate gene absence. B Abundance of NifHDK operons (nifHDK, vnfHDK, or anfHDK) present in contigs longer than 5000 bps across gut metagenomes. The color scale represents the log-transformed transcripts per million (TPM). The tree represents a simplified time-calibrated phylogenetic tree reconstructed using host termite mitochondrial genomes