PhlD is proposed to condense three malonyl-CoAs to form phloroglucinol
Phloroglucinol is known for its broad-spectrum antiviral, antibacterial, antifungal, anthelmintic, and phytotoxic activities. 2,4-Diacetylphloroglucinol (2,4-DAPG), produced by plant-associated Pseudomonas, is particularly important in agriculture due to its antifungal activity. 43-45 The 2,4-DAPG biosynthesis gene cluster contains six genes, phlABCDEF, of which phlACBD is responsible for 2,4-DAPG biosynthesis. Two hypotheses were proposed regarding the biosynthetic pathway leading to the formation of 2,4-DAPG: (1) Bangera and Thomashow proposed that PhlD condenses two malonyl-CoAs and one acetyl-CoA to form 2-monoacetylphloroglucinol, Subsequent conversion to 2,4-DAPG by PhlABC.46 (2) However, Achkar et al. PhlD is proposed to condense three malonyl-CoAs to form phloroglucinol, which can also be converted to 2,4-DAPG by PhlABC (Scheme 7).