To be specific, certain "P. fluorescens" isolates produce the secondary metabolite 2,4-diacetylphloroglucinol (2,4-DAPG), the compound found to be responsible for antiphytopathogenic and biocontrol properties in these strains. The "phl" gene cluster encodes factors for 2,4-DAPG biosynthesis, regulation, export, and degradation. Eight genes, "phlHGFACBDE", are annotated in this cluster and conserved organizationally in 2,4-DAPG-producing strains of "P. fluorescens". Of these genes, "phlD" encodes a type III polyketide synthase, representing the key biosynthetic factor for 2,4-DAPG production. "PhlD" shows similarity to plant chalcone synthases and has been theorized to originate from horizontal gene transfer. Phylogenetic and genomic analysis, though, has revealed that the entire "phl" gene cluster is ancestral to "P. fluorescens", many strains have lost the capacity, and it exists on different genomic regions among strains.