Fig. 4: The diversity of Myxococcota in global WWTPs.

Phylogenetic tree inferred from full-length 16S rRNA gene sequences within the phylum Myxococcota originated from global WWTPs (A) and the myxobacterial genera with presumed predatory behavior therein (B). The tree was constructed with 507 representative OTU sequences from a local WWTP (WWTP01) and 1 010 representative OTU sequences from the MiDAS 4 database [30]. The inner-ring color and labels indicate family classification with the SILVA database [46]. The external bars showed the average relative abundance of the OTUs at the WWTP01 across eight aerobic activated sludge samples collected over two years (maximum 0.07%). The scale bar corresponds to 0.1 substitutions per nucleotide position. Red-colored branches indicate sequences ≥94.5% identical to 16S rRNA gene sequences of myxobacteria with reported predatory behavior (suggesting potential predators at the genus level), the number of which was summarized for each myxobacterial genus in B. The numbers above bars indicate the proportion of the potential predators in each genus. Phylogenetic trees were inferred for Haliangium (C), the mle1-27 clade (D), and Pajaroellobacter (E) across different habitats. The trees were constructed with representative OTU sequences from WWTP01 (174, 134, and 69 sequences, for Haliangium, the mle1-27 clade, and Pajaroellobacter, respectively) and sequences obtained from the SILVA database [46] with known isolation source (507, 49, and 102 sequences, respectively).