• Korean Journal of Microbiology
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• v.30 no.4
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• pp.286-290
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• 1992

The present study was performed to isolate the fluorescent pseudomonads from Kwang-Ju soil and to construct a mutant strain defective in siderophore biosynthesis. The siderophore-secreting pseudomonads were screened on Blue agar (Chrome Azuol S agar) plates and one strain of them was designated to Pseudominas fluorescens (P. fluorescens) PY002. To construct a mutant defective in siderophore biosynthesis, P. fluorescens PY002 was randomly mutagenized with a transposon Tn5. The location of Tn5 integrated into chromosomal of the mutants strain was determined by Southern blot analysis. The mutagenized strain showed non-fluorescent on a King's B agar plate and were defective in iron (III) acquisition ability.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.4
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• pp.275-282
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• 2000

Among the fluorescent pseudomonad isolates from soil- root system of red pepper in Chinju, Kyunsangnam-Do, the phylogenetic analysis for 35 isolates were conducted. The partial 16S ribosomal DNA sequences were used as taxonomic key for phylogenetic analyses, and these sequences were enabled to identification of the fluorescent pseudomonad isolates on the species level. The 17 isolates among them were classified into Pseudomonas putida group, and consisted of the strains isolated mainly from soil. This group were subdivided into 4 subgroups (I, II, III, and IV). The subgroup I and IV were unique ones which were relatively remotely related with subgroup II and III including the type strain of P. putida. The 15 isolates among 35 isolates were grouped along with the type strain of Pseudomonas fluorescens, and 3 isolate were characterized as intermediates of P. fluorescens and Pseudomonas chlororaphis. Most of strain isolateds from the rhizosphere soil and rhizoplane of red pepper were identified as P. fluorescens and closely related with each other. In this study, root of red pepper was supposed to be colonized by a specific strain or strains of P. fluorescens.

• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.86-90
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• 2005

Strain M-18 was isolated from the rhizosphere soil of sweet melon, using 1-aminocyclopropane-1-carboxylate (ACC) as a sole nitrogen source. Its phenotypic characteristics, metabolic tests, and 16S rDNA sequence were analyzed. The antibiotics secreted by strain M-18 were determined to be phenazine 1-carboxylic acid and pyoluteorin. These data showed that strain M-18 was a new fluorescent Pseudomonas strain that produced both phenazine 1-carboxylic acid and pyoluteorin, some features being similar to Pseudomonas aeruginosa and Pseudomonas fluorescens. Therefore, the strain M-18 appears to be the first pseudomonad described to date that is capable of producing both phenazine 1-carboxylic acid and pyoluteorin.

• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1688-1694
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• 2009

A novel strain of fluorescent pseudomonad (PB-St2) was isolated from surface-sterilized stems of sugarcane grown in Pakistan. The bacterium was identified as Pseudomonas aurantiaca on the basis of 16S rRNA gene sequence analysis and results from physiological and biochemical characteristics carried out with API50 CH and QTS 24 bacterial identification kits. Assays using substrate-specific media for enzymes revealed lipase and protease activities but cellulase, chitinase, or pectinase were not detected. The bacterium was unable to solubilize phosphate or produce indole acetic acid. However, it did produce HCN, siderophores, and homoserine lactones. In dual culture assays on agar, the bacterium showed antifungal activity against an important pathogen of sugarcane in Pakistan, namely Colletotrichum falcatum, as well as for pathogenic isolates of Fusarium oxysporium and F. lateritium but not against F. solani. The antifungal metabolites were identified using thin-layer chromatography, UV spectra, and MALDI-TOFF spectra and shown to be phenazine-1-carboxylic acid (PCA), 2-hydroxyphenazine (2-OH-PHZ), and N-hexanoyl homoserine lactone (HHL) (assessed using only TLC data). The capacity of this bacterium to produce HCN and 2-OH-PHZ, as well as to inhibit the growth of C. falcatum, has not been previously reported.