Phloroglucinol Derivatives in Plant-Beneficial Pseudomonas spp.: Biosynthesis, Regulation, and Functions

Abstract

Plant-beneficial Pseudomonas spp. aggressively colonize the rhizosphere and produce numerous secondary metabolites, such as 2,4-diacetylphloroglucinol (DAPG). DAPG is a phloroglucinol derivative that contributes to disease suppression, thanks to its broad-spectrum antimicrobial activity. A famous example of this biocontrol activity has been previously described in the context of wheat monoculture where a decline in take-all disease (caused by the ascomycete Gaeumannomyces tritici) has been shown to be associated with rhizosphere colonization by DAPG-producing Pseudomonas spp. In this review, we discuss the biosynthesis and regulation of phloroglucinol derivatives in the genus Pseudomonas, as well as investigate the role played by DAPG-producing Pseudomonas spp. in natural soil suppressiveness. We also tackle the mode of action of phloroglucinol derivatives, which can act as antibiotics, signalling molecules and, in some cases, even as pathogenicity factors. Finally, we discuss the genetic and genomic diversity of DAPG-producing Pseudomonas spp. as well as its importance for improving the biocontrol of plant pathogens.

Exploring the Antivirulence Activity of Pulverulentone A, a Phloroglucinol-Derivative from Callistemon citrinus Leaf Extract, against Multi-Drug Resistant Pseudomonas aeruginosa

“…Interestingly, the plant-beneficial microorganisms such as Pseudomonas spp. produce several phloroglucinol derivatives such as 2,4-diacetylphloroglucinol, commonly recognized as secondary metabolites with an important role as antibiotics via signaling molecules and as pathogenicity factors [ 30 ]. In addition, these phloroglucinol derivatives were recently regarded as effective bio-control agents that provide protection for the plant root system from numerous soil-borne plant diseases [ 30 ].…”

Pyoluteorin and 2,4-diacetylphloroglucinol are major contributors to Pseudomonas protegens Pf-5 biocontrol against Botrytis cinerea in cannabis

“…Altogether, these results are thus encouraging regarding the sustainable use of antibiotic-producing Pseudomonas spp. as biocontrol agents ( Biessy and Filion, 2021 ).…”

“…The genes required for DAPG biosynthesis are located within a highly conserved 6.5-kb genomic DNA fragment comprising nine open reading frames ( phlACBDEFGHI ) grouped together in a biosynthetic gene cluster. Four of these genes ( phlACBD ) constitute the operon directly involved in the biosynthesis, while the others ( phlEFGHI ) code for efflux, degradation, and regulatory proteins ( Gross and Loper, 2009 ; Biessy and Filion, 2021 ). Notably, phlA , phlC , and phlB encode the subunits of a multimeric enzyme that catalyzes the conversion of phloroglucinol to MAPG, and of MAPG to DAPG ( Pavkov-Keller et al, 2019 ).…”

Genome mining andIn‐silicodetermination of secondary metabolites of bacteria againstFusarium oxysporumf. sp.Lycopersici

“…Similarly, DAPG are secondary metabolites usually produced by Pseudomonas spp. and they are involved in elicitation of plant defence system through induced systemic resistance and directly in the modulation of plant hormonal balance (Biessy & Filion, 2021;Brazelton et al, 2008;Weller et al, 2012). DAPG present in P. fluorescens has been reported to be responsible for the antagonistic property against Athelia rolfsil, a fungus causing rot and wilt on more than 500 plant species (Zhou et al, 2014).…”