The rhizobacterium Pseudomonas aeruginosa M18 can produce a broad spectrum of secondary metabolites, including the antibiotics pyoluteorin (Plt) and phenazine-1-carboxylic acid (PCA), hydrogen cyanide, and the siderophores pyoverdine and pyochelin. The antibiotic biosynthesis of M18 is coordinately controlled by multiple distinct regulatory pathways, of which the GacS/GacA system activates Plt ...

2, 4-Diacetylphloroglucinol (2,4-DAPG), a natural phenolic compound, has been investigated in light of its biological activities against plant pathogens. To improve its potential application, fourteen 2,4-DAPG analogous were synthesized through the Friedel-Crafts reaction using acyl chlorides and phloroglucinol. Of the 2,4-DAPG derivatives, MP4 exhibited much higher antifungal activity against ...

Pseudomonas sp. M18, isolated from the watermelon rhizosphere, is antagonistic against a number of soil-borne pathogens. This strain produces an uncharacterized red pigment, pyoluteorin (Plt), and two N-acylhomoserine lactones (AHLs). A previously isolated red-pigment-defective mutant, M18-T510, contains an insert within a gene similar to rhlI in P. aeruginosa PAO1. The M18 rhlI gene product is...

A diverse and versatile spectrum of metabolic activities among isolates of fluorescent Pseudomonas putida indicates their adaptability to various niches. These polyhydroxybutyrate producing and phosphate solubilizing isolates showed a high level of functional and genetic versatility among themselves. One of the potential P. putida isolate P132 can contribute as a candidate agent for both biocon...

Kwak, Y.-S., Bakker, P. A. H. M., Glandorf, D. C. M., Rice, J. T., Paulitz, T. C., and Weller, D. M. 2009. Diversity, virulence, and 2,4-diacetylphloroglucinol sensitivity of Gaeumannomyces graminis var. tritici isolates from Washington State. Phytopathology 99:472-479. We determined whether isolates of the take-all pathogen Gaeumannomyces graminis var. tritici become less sensitive to 2,4-diac...

Bacterial extracellular electron transfer (EET) is envisioned for use in applied biotechnologies, necessitating electrochemical characterization of natural and engineered electroactive biofilms under conditions similar to the target application, including small-scale biosensing or biosynthesis platforms, which often distinct from standard 100 mL-scale stirred-batch bioelectrochemical test platf...

Plants have evolved strategies of stimulating and supporting specific groups of antagonistic microorganisms in the rhizosphere as a defense against diseases caused by soilborne plant pathogens owing to a lack of genetic resistance to some of the most common and widespread soilborne pathogens. Some of the best examples of natural microbial defense of plant roots occur in disease suppressive soil...

Production of 2,4-diacetylphloroglucinol (2,4-DAPG) in the rhizosphere by strains of fluorescent Pseudomonas spp. results in the suppression of root diseases caused by certain fungal plant pathogens. In this study, fluorescent Pseudomonas strains containing phlD, which is directly involved in the biosynthesis of 2,4-DAPG, were isolated from the rhizosphere of wheat grown in soils from wheat-gro...

Some soil bacteria protect plants against soil-borne diseases by producing toxic secondary metabolites. Such beneficial biocontrol bacteria can be used in agricultural systems as alternative to agrochemicals. The broad spectrum toxins responsible for plant protection also inhibit predation by protozoa and nematodes, the main consumers of bacteria in soil. Therefore, predation pressure may favou...