Simple "on-demand" production of bioactive natural products.

Exchange of the native promoter to the arabinose-inducible promoter P-BAD was established in entomopathogenic bacteria to silence and/or activate gene clusters involved in natural product biosynthesis. This allowed the on-demand production of GameXPeptides, xenoamicins, and the blue pigment indigoidine. The gene clusters for the novel mevalagmapeptides and the highly toxic xenorhabdins were identified by this approach.