Repartition of superoxide reductase (SOR) and superoxide dismutase (SOD) genes regarding the 16S rRNA gene distance tree of all archaeal described in SORGOdb. All of the sequences were retrieved from SILVA  when available or GenBank (http://www.ncbi.nlm.nih.gov/). SOR are represented with a single green arrow, Dx-SOR with a double khaki arrow, Fe-Mn SOD by a light blue dot and Cu-Zn SOD by a dark blue dot. SOD-type genes were determined using OxyGene . Scale bar: 3% difference. Crenarchaeota (in red) are developed in Figure 4.