The biocontrol ability of pseudomonads is directly correlated with production of potential antibiotics such as 2,4-diacetylphloroglucinol (2,4-DAPG) which exhibits broad antiviral, antibacterial, antifungal and antihelminthic properties and induces systemic resistance and systemic tolerance in the host plant. The antifungal metabolite 2,4-DAPG is synthesized through the expression of the six genes phlFACBDE which forms the phl operon. The different functions of these genes have been well characterized of which phlD plays an important role in the biosynthesis of the precursor molecule for 2,4-DAPG production, phlE acts as an exporter of 2,4- DAPG metabolic (toxic) intermediates, phlG is involved in the degradation of 2,4-DAPG, phlF is a pathway-specific repressor and phlH acts as a regulator. Among these genes phlD is a key gene involved in the synthesis of monoacetylphloroglucinol (MAPG), the precursor of 2,4-DAPG from acetoacetylCoA which encodes for a polyketide synthase. Pseudomonas fluorescens strains that produce the polyketide antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) are the most effective rhizobacteria that suppress root and crown rots, blast, wilts, and damping-off diseases of a variety of crops under field conditions. A number of commercial products of Pseudomonas spp. have been successfully employed in agriculture systems.