The genome of plant-associated Bacillus amyloliquefaciens FZB42 harbors an array of
giant gene clusters involved in synthesis of lipopeptides and polyketides with antifungal,
antibacterial and nematocidal activity. Five gene clusters, srf, bmy, fen, nrs, dhb,
covering altogether 137 kb, were shown to direct synthesis of the cyclic lipopeptides
surfactin, bacillomycin, fengycin, an unknown peptide, and the iron-siderophore bacillibactin.
In addition, one gene cluster encoding enzymes involved in synthesis and export of
the antibacterial dipeptide bacilysin is also functional in FZB42. Three gene clusters,
mln, bae, and dfn, with a total size of 199 kb were shown to direct synthesis of the
antibacterial acting polyketides macrolactin, bacillaene, and difficidin. In total,
FZB42 dedicates about 340 kb, corresponding to 8.5% of its total genetic capacity,
to synthesis of secondary metabolites. On the contrary, genes involved in ribosome-dependent
synthesis of lantibiotics and other peptides are scarce. Apart from two incomplete
gene clusters directing immunity against mersacidin and subtilin, only one peptide-like
compound has been detected in the culture fluid that inhibits the growth of B. subtilis
lacking the alternative sigma factor W.