Map of the YBT locus in (A) Y. pestis 91001, (B) P. syringae DC3000, and (C) P. luminescens TTO1, according to annotated genomes. The genes are designed according to the encoded protein functions: black, biosynthetic enzymes, apart from ybtS homologues, represented by a dark squaring; gray, membrane receptors; horizontal lines, transport proteins; light squaring, regulatory proteins; and vertical lines, proteins of unknown function. The white-coded genes have no homologues in the other species.