• Journal of Microbiology and Biotechnology
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• v.30 no.5
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• pp.689-699
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• 2020

Brevibacillus brevis GZDF3 is a gram-positive, plant growth-promoting rhizosphere bacterium (PGPR) isolated from the rhizosphere soil of Pinellia ternata (an important herb in traditional Chinese medicine). The GZDF3 strain produces certain active compounds, such as siderophores, which are the final metabolite products of non-ribosomal peptide synthetase (NRPS) and independent non-ribosomal peptide synthetase (NIS) activity. With the present study, we attempted to investigate the siderophore production characteristics and conditions of Bacillus sp. GZDF3. The antibacterial activity of the siderophores on pathogenic fungi was also investigated. Optimal conditions for the synthesis of siderophores were determined by single factor method, using sucrose 15 g/l, asparagine 2 g/l, 32℃, and 48 h. The optimized sucrose asparagine medium significantly increased the production of siderophores, from 27.09% to 54.99%. Moreover, the effects of different kinds of metal ions on siderophore production were explored here. We found that Fe³⁺ and Cu²⁺ significantly inhibited the synthesis of siderophores. The preliminary separation and purification of siderophores by immobilized-metal affinity chromatography (IMAC) provides strong antibacterial activity against Candida albicans. The synergistic effect of siderophores and amphotericin B was also demonstrated. Our results have shown that the GZDF3 strain could produce a large amount of siderophores with strong antagonistic activity, which is helpful in the development of new biological control agents.

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.2
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• pp.152-159
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• 1990

Four active strains, producing siderophore and antagonizing to soil plant disease fungi, were isolated and identified from the wheat rhizosphere to reduce the injurious effects of continuous cropping and study on the biological control. The obtained results were summerized as follow. 1. Four strains of fluorescent Pseudomonas were isolated from the wheat rhizosphere and identified as Pseudomonas fluorescens Biotype A(Ps-1,2,5) and Biotype B(Ps-3) That strains inhibitied growth of R. solani, F.oxysperum and F. solani in vitro 2. Optical density of pigment was maximum at 410nm. 3. Siderophore production by identified strains was decreased with addition of $Fe^{+3}$, although not decreased with addition of $Fe^{+2}$ 4. Pigment of Ps-1, 2 and 3 strain inhibitied growth of R. slani, F. oxysperum and F. solani but pigment of Ps-5 strain did not inhibitie growth of R. solani 5. Effect of inoculation was in order of Ps-2, 1, 5 and 3 strain through the dark culture method, and effect of Ps-1 and Ps-2 was greater than that of treatment of captan 50ppm.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.10b
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• pp.14-14
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• 2003

The aim of the present study isto assess the importance of siderophore producing rhizosphere bacteria on the growth of Brassica junceaunder chromium stress. Pseudomonassp. (A4) produced an iron chelating substance siderophores in iron deficient medium. Under chromium stress condition Pseudomonassp. (A4) markedly increased the root and shoot length and also biomass of Brassica juncea as compared to Pseudomonas sp. (A3). This plant growth promotion has been related to the microbial production of siderophore.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.10b
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• pp.45-45
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• 2003

The aim of the present study was to assess the importance of siderophore producing rhizobacteria on the growth of Brassica juncea under chromium stress. Pseudomonas sp. (A4) produced an iron chelating substance siderophores in iron deficient medium. Under chromium stress condition Pseudomonassp. (A4) markedly increased the root and shoot length and also biomass of Brassica juncea as compared to Pseudomonas sp. (A3). This plantgrowth promotion has been related to the microbial production of siderophore.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.10a
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• pp.20-29
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• 2003

The aim of the present study isto assess the importance of siderophore producing rhizosphere bacteria on the growth of Brassica junceaunder chromium stress. Pseudomonassp. (A4) produced an iron chelating substance siderophores in iron deficient medium. under chromium stress condition Pseudomonassp. (A4) markedly increased the root and shoot length and also biomass of Brassica juncea as compared to Pseudomonas sp. (A3). This plant growth promotion has been related to the microbial production of siderophore.

• The Korean Journal of Mycology
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• v.40 no.1
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• pp.44-48
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• 2012

Ginseng (Panax ginseng) is one of the most widely cultivated medicinal herb in Korea. However, yield losses reached up to 30~60 % due to various diseases during 3 or 5 years of ginseng cultivation. Therefore, successful production of ginseng roots depends primarily on the control of diseases. The objective of this study is to select potential multifunctional biocontrol agents from actinomycetes for the control of multiple ginseng diseases as an alternative to fungicides. Ninety three Streptomyces strains were selected and their ability to produce antibiotics, siderophore and lytic enzymes such as protease and cellulose were investigated. Eight of the isolates, strains A75, A501, 515, 523, A704, A1444, A3265 and A3283 produced cellulase and protease. These strains also produced siderophore and showed potent antifungal activity against Botrytis cinerea, Cylindrocarpon destructans, Collectotricum gloeosporioides, Phytophthora capsici and Rhizoctonia solani causing ginseng root rot.

• Journal of Life Science
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• v.17 no.12
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• pp.1682-1688
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• 2007

To develop multifunctional microbial inoculant, microorganisms with antagonistic activity and biofertilizing activity were screened. Pantoea agglomerans and Bacillus megaterium from our laboratory culture collection, and strain MF12 from soil near poultry farm in Miryang were selected. On the basis of morphological, physiological studies and 16S rDNA sequence analysis, isolate MF12 was identified as the Bacillus pumilis. Three strains were studied for insoluble phosphate solubilization, indole-3-acetic acid (IAA) and siderophore production, ammonification ability, hydrolytic enzyme production and antifungal activity against phytopathogenic fungi. P. agglomerans did not produce any visible clear zone on agar plate containing 0.5% $Ca_3(PO_4){_2}$ as a sole phosphorus source. However, this strain could solubilize insoluble phosphate in liquid medium. All strains produced IAA ranged from $3{\sim}639{\mu}g/ml$ depending on culture time and had ammonification ability. Among three strains, only P. agglomerans produced siderophore. P. agglomerans produced pectinase and lipase, B. megaterium produced amylase, protease and lipase while B. pumilis produced protease and lipase. P. agglomerans showed antifungal activities against phytopathogenic fungi, Fusarium oxysporum and Colletotrichum gloeosporioides. B. pumilis showed antifungal activities against Botrytis cinerea, Sclerotinia sclerotiorum and Phythium ultimum.

• Journal of Mushroom
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• v.19 no.3
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• pp.134-139
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• 2021

A diverse group of plant-growth promoting bacteria were isolated in button mushroom (Agaricus bisporus) media to investigate the plant-growth promoting traits of compounds including indole acetic acid (IAA), ammonia, 1-aminocyclopropane-1-carboxylic acid deaminase, siderophore, and hydrogen cyanide. Twenty-one bacterial strains showing positive effects for all the test traits were selected and classified to confirm bacterial diversity in the media habitat. Plant-growth promoting traits of the isolates were also assessed. All strains produced IAA ranging from 20 ㎍/mL to 250 ㎍/mL. Most of the isolates produced more than 80% siderophore. Four strains (Pantoea sp., PSB-08, Bacillus sp., PSB-13, Pseudomonas sp., PSB-17, and Enterobacter sp., PSB-21) showed outstanding performances for all the tested traits. In a bioassay of these four strains using mung bean plant, the best growth performances (23.16 cm, 22.98 cm, 2.27 g/plant, and 1.83 g/plant for shoot length, root length, shoot dry weight, and root dry weight, respectively) were obtained from the plants co-inoculated with Bacillus sp., PSB-13. The resultant data indicate that button mushroom media have got a diverse group of bacteria with plant growth promoting abilities. Thus, the media could be a good recycling resource for using to an effective bio-fertilizer.

• Microbiology and Biotechnology Letters
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• v.51 no.4
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• pp.484-499
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• 2023

Plant growth-promoting (PGP) bacteria can be used as bioresources to enhance phytoremediation through their PGP traits and pollutant removal capacity. In this study, 49 rhizobacteria were primarily isolated from the rhizosphere of tall fescue grown in diesel- and heavy metal-contaminated soil. Their biosurfactant production, phosphate (P) solubilization, and siderophore production were qualitatively and quantitatively evaluated to identify superior PGP bacteria. The optimal conditions for the growth of PGP bacteria and the stability of their PGP traits were a temperature of 35℃, a pH of 7, and 2 days of cultivation time. Four superior PGP bacteria (Pseudomonas sp. NL3, Bacillus sp. NL6, Bacillus sp. LBY14, and Priestia sp. TSY6) were finally selected. Pseudomonas sp. NL3 exhibited superior biosurfactant production and P solubilization. Bacillus sp. NL6 showed the highest P solubilization and superior production of biosurfactants and siderophores. Bacillus sp. LBY14 offered the best siderophore production and impressive P solubilization. Priestia sp. TSY6 had superior capacity for all three PGP traits. Through their secretion of beneficial PGP metabolites, the four bacteria isolated in this study have the potential for use in the phytoremediation of contaminated soil.

• The Plant Pathology Journal
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• v.29 no.3
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• pp.323-329
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• 2013

The stationary-phase sigma factor, RpoS, influences the expression of factors important in survival of Pseudomonas chlororaphis O6 in the rhizosphere. A partial proteomic profile of a rpoS mutant in P. chlororaphis O6 was conducted to identify proteins under RpoS regulation. Five of 14 differentially regulated proteins had unknown roles. Changes in levels of proteins in P. chlororaphis O6 rpoS mutant were associated with iron metabolism, and protection against oxidative stress. The P. chlororaphis O6 rpoS mutant showed increased production of a pyoverdine-like siderophore, indole acetic acid, and altered isozyme patterns for peroxidase, catalase and superoxide dismutase. Consequently, sensitivity to hydrogen peroxide exposure increased in the P. chlororaphis O6 rpoS mutant, compared with the wild type. Taken together, RpoS exerted regulatory control over factors important for the habitat of P. chlororaphis O6 in soil and on root surfaces. The properties of several of the proteins in the RpoS regulon are currently unknown.