Fig. 1

Organization of the Fit gene cluster and their homologues (mcf). In P. protegens and P. chlororaphis the fit gene cluster (fitA-H) is composed of eight ORFs encoding the insecticidal toxin (red arrow), predicted components of a toxin secretion system (orange arrows) including an outer membrane protein (OMP), and regulators of toxin production (green arrows). The orientation of the toxin gene within the genome is indicated by + for the leading strand and by – for lagging the strand. Transporter homologues (mtpBDE) are only found in P. luminescens adjacent to mcf2, a truncated variant of mcf1. X. bovienii SS2004 and P. asymbiotica ATTC 43949 harbor only one mcf variant. Blue arrows indicate flanking genes, which share no homology among the strains represented. The phylogenetic relationship of P. protegens, P. chlororaphis, Photorhabdus spp. and Xenorhabdus spp. with representative orders/families and groups of γ-proteobacteria is based on concatenated RecA, RpoB and RpoD protein sequences