LuxI homologs in Novosphingobium strains. (A) Phylogenetic tree depicting the evolutionary relationship of the curated LuxI homologs and the putative LuxI homologs from Novosphingobium strains. (B) Alignment of LuxI homologs used in the construction of phylogenetic trees. Asterisk indicates amino acid residues that are 100% conserved in all LuxI homologs. (C) Linear comparison of luxI/R pairs identified in the Novosphingobium strains and the surrounding genes within 5,000 bp of the luxI homolog. Arrows with black dots represents genes coding for hypothetical proteins.