Extended Data Fig. 4: Contribution of UBA868 sulfur oxidizing genes to the overall expression and in the metagenomes, and phylogeny of SoxB peptides.

(A) Average contribution of UBA868 for other genes in the pathways to oxidize sulfur oxidation is highest in the mesopelagic (MES) than in the deep chlorophyll maximum (DCM) or in the surface (SRF). soxB expression and gene abundance were quantified with the KO specific for it and HMM profiles specific for peptides annotated as “thiosulfohydrolase SoxB” in RefSeq and the peptides retrieved with the TIGRFAM specific for SoxB. The contribution of the two subunits for the RuBisCO genes, large and small subunits, rbcL and rbcS is also represented. HMM profiles were also designed to tell apart the contribution of rbcL type I and II. (B) SAR324 SoxB peptides fall in two subclusters, most of which are outside the groups with RefSeq and UBA868 peptides. Only those SAR324 genomes that cluster with RefSeq are predicted to have soxAXYZ (predicted with their KOs). For the rest of taxa, the pathway seems incomplete. The phylogenetic reconstruction suggests that the KO specific for it retrieves SoxB peptides in the SAR324, Flavobacteriales, Pirellulales and part of the Alphaproteobacteria, that might instead have a related but different function from SoxB. Phylogenetic trees were obtained with IQ-TREE as described in the main text.