Genome Sequences of Allochromatium palmeri and Allochromatium humboldtianum Expand the Allochromatium Family Tree of Purple Sulfur Photosynthetic Bacteria within the Gammaproteobacteria and Further Refine the Genus.

New genomes of two Allochromatium strains were sequenced. Whole-genome and average nucleotide identity based on BLAST (ANIb) comparisons show that Allochromatium humboldtianum is the nearest relative of Allochromatium vinosum (ANIb, 91.5%), while both Allochromatium palmeri and Thermochromatium tepidum are more distantly related (ANIb, <87%). These new sequences firmly establish the position of Allochromatium on the family tree.