• Preventive Nutrition and Food Science
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• v.6 no.3
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• pp.192-196
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• 2001

Ethanol extracts from 36 vegetable samples were assayed for their growth-promoting effects on Bifidobacterium bifidum, B. longum, and Lactobacillus casei The growth-promoting effects varied according to bacterial strain and vegetable species. In modified Gy rgy broth, extracts of Lactuca sativa, Lycopersicon esculentum and L escutentum var. cerasiforme exhibited strong growth-promoting responses toward B. longum, and significant and strong growth- promoting response toward B. bifidum was observed in extracts of Actinidia arguta, Allium cepa, A. sativum, Brassica campestris subsp. napus vats. pekinensis, Capsicum frutescens, Daucus carota var. sativa, L sativa, 1. esculentum and L. esculentum var. cerasforme, Nelumbo nucifera, Cucurbita moschata, Lackca sativa var. capitata, and Rubus coreanus. For L casei, extracts of A. fshlosum, A. hberosum, Cichorium intbus, Cucurbita moschat\ulcorner Ipomoea batatas, 1. sativa var. capitata, L. esculentum, P. brachycarpa, Raphanus sativus, R. coreanus, and S. melongena strongly enhanced the growth of this bacteria. In modified Gy rgy broth, the promoting effect was most pronounced with B. bifidum and L. casei among lactic acid bacteria used. In MRS broth, A. arguta, A. cepa, A. sativum, B. campestris subsp. napus var. pekinensis, C. frutescens, and D. carota var. sativa L. satiw var. capitata, and R. coreanus strongly enhanced the growth of B. bifidum, Growth of B. longum was strongly affected by the addition of extracts from L. sativa var. capitata. For L casei, moderate growth-promoting responses were observed in 9 vegetable extracts. The promoting effect in MRS broth was most pronounced with B. bifidum among lactic acid bacteria used.

• Journal of Microbiology and Biotechnology
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• v.31 no.9
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• pp.1218-1230
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• 2021

Cold-adapted plant growth-promoting bacteria (PGPB) with multiple functions are an important resource for microbial fertilizers with low-temperature application. In this study, culturable cold-adapted PGPB strains with nitrogen fixation and phosphorus solubilization abilities were isolated. They were screened from root and rhizosphere of four dominant grass species in nondegraded alpine grasslands of the Qilian Mountains, China. Their other growth-promoting characteristics, including secretion of indole-3-acetic acid (IAA), production of siderophores and ACC deaminase, and antifungal activity, were further studied by qualitative and quantitative methods. In addition, whether the PGPB strains could still exert plant growth-promoting activity at 4℃ was verified. The results showed that 67 isolates could maintain one or more growth-promoting traits at 4℃, and these isolates were defined as cold-adapted PGPB. They were divided into 8 genera by 16S rRNA gene sequencing and phylogenetic analysis, of which Pseudomonas (64.2%) and Serratia (13.4%) were the common dominant genera, and a few specific genera varied among the plant species. A test-tube culture showed that inoculation of Elymus nutans seedlings with cold-adapted PGPB possessing different functional characteristics had a significant growth-promoting effect under controlled low-temperature conditions, including the development of the roots and aboveground parts. Pearson correlation analysis revealed that different growth-promoting characteristics made different contributions to the development of the roots and aboveground parts. These cold-adapted PGPB can be used as excellent strain resources suitable for the near-natural restoration of degraded alpine grasslands or agriculture stock production in cold areas.

• 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.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.759-771
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• 2023

Plant growth-promoting rhizobacteria (PGPR) are naturally occurring bacteria that intensively colonize plant roots and are crucial in promoting the crop growth. These beneficial microorganisms have garnered considerable attention as potential bio-inoculants for sustainable agriculture. PGPR directly interacts with plants by providing essential nutrients through nitrogen fixation and phosphate solubilization and accelerating the accessibility of other trace elements such as Cu, Zn, and Fe. Additionally, they produce plant growth-promoting phytohormones, such as indole acetic acids (IAA), indole butyric acids (IBA), gibberellins, and cytokinins.PGPR interacts with plants indirectly by protecting them from diseases and infections by producing antibiotics, siderophores, hydrogen cyanide, and fungal cell wall-degrading enzymes such as glucanases, chitinases, and proteases. Furthermore, PGPR protects plants against abiotic stresses such as drought and salinity by producing 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase and modulating plant stress markers. Bacteria belonging to genera such as Bacillus, Pseudomonas, Burkholderia, Pantoa, and Enterobacter exhibit multiple plant growth-promoting traits, that can enhance plant growth directly, indirectly, or through synergetic effects. This comprehensive review emphasizes how PGPR influences plant growth promotion and presents promising prospects for its application in sustainable agriculture.

• Journal of Microbiology
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• v.45 no.2
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• pp.171-174
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• 2007

The growth stimulation of wild plants by several bacterial species showing plant growth-promoting capabilities was examined in a barren lakeside area at Lake Paro, Korea. Microbial numbers and activities in the field soil were monitored for 73 days after inoculation of the bacteria. The acridine orange direct counts for the total soil bacterial populations ranged between $2.0-2.3{\times}10^{9}\;cells/g$ soil and $1.4-1.8{\times}10^{9}\;cells/g$ soil in the inoculated and uninoculated soils, respectively. The numbers of Pseudomonas spp., which is known as a typical plant growth-promoting rhizobacteria, and the total microbial activity were higher in the inoculated soil compared to those in the uninoculated soil. The average shoot and root lengths of the wild plants grown in the inoculated soil were 17.3 cm and 12.4 cm, respectively, and longer than those of 11.4 cm and 8.5 cm in the uninoculated soil. The total dry weight of the harvested wild plants was also higher in the inoculated soil (42.0 g) compared to the uninoculated soil (35.1 g). The plant growth-promoting capabilities of the inoculated bacteria may be used for the rapid revegetation of barren or disturbed land, and as biofertilizer in agriculture.

• Journal of Microbiology and Biotechnology
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• v.31 no.3
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• pp.398-407
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• 2021

Using salt-tolerant bacteria to protect plants from salt stress is a promising microbiological treatment strategy for saline-alkali soil improvement. Here, we conducted research on the growth-promoting effect of Brevibacterium frigoritolerans on wheat under salt stress, which has rarely been addressed before. The synergistic effect of B. frigoritolerans combined with representative salt-tolerant bacteria Bacillus velezensis and Bacillus thuringiensis to promote the development of wheat under salt stress was also further studied. Our approach involved two steps: investigation of the plant growth-promoting traits of each strain at six salt stress levels (0, 2, 4, 6, 8, and 10%); examination of the effects of the strains (single or in combination) inoculated on wheat in different salt stress conditions (0, 50, 100, 200, 300, and 400 mM). The experiment of plant growth-promoting traits indicated that among three strains, B. frigoritolerans had the most potential for promoting wheat parameters. In single-strain inoculation, B. frigoritolerans showed the best performance of plant growth promotion. Moreover, a pot experiment proved that the plant growth-promoting potential of co-inoculation with three strains on wheat is better than single-strain inoculation under salt stress condition. Up to now, this is the first report suggesting that B. frigoritolerans has the potential to promote wheat growth under salt stress, especially combined with B. velezensis and B. thuringiensis.

• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.223-228
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• 2011

BACKGROUND: Rhizosphere bacteria may improve plant growth and productivity both by supply nutrients and hormonal stimulation. Although many experiments have shown improvements in plant growth with inoculation of bacterial cultures to the rhizosphere, the main obstacle in the applications of plant growth promoting rhizobacteria in a large scale is the inconsistency of the results. We tested the growth promoting effects of Azospirillum and Methylobacterium strains on red pepper plant. METHODS AND RESULTS: Red pepper seedlings were grown for 25 days in a growth media inoculated with A. brasilense CW903 or M. oryzae CBMB20. The seedlings were transplanted and grown for 45 days in pots with soil in a greenhouse, at half the recommended level of fertilizer. Bacterial culture, $4.0{\times}10^9$ for A. brasilense CW903 and $5.8{\times}10^8$ CFU for M. oryzae CBMB20, was applied in root zone soil periodically every 10 days during the experiment. Inoculation of M. oryzae CBMB20 significantly increased the red pepper plant growth in terms of leaf number, height and mass of shoot, or root mass compared to uninoculated control plants. Although beneficial effects of A. brasilense on plant growth of many crops were observed, the growthpromoting effect of A. brasilense CW903 on red pepper plant was not found in this study. CONCLUSION(s): The factors responsible for the irregularities in plant growth promoting of rhizobacteria are difficult to elucidate. Extensive inoculation experiments in the greenhouse and in the field should enable us to define the factors critical to obtain successful application of plant growth promoting rhizobacteria.

• Journal of Microbiology and Biotechnology
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• v.19 no.11
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• pp.1431-1438
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• 2009

The role of plant growth-promoting rhizobacteria (PGPR) in the phytoremediation of heavy-metal-contaminated soils is important in overcoming its limitations for field application. A plant growth-promoting rhizobacterium, Serratia sp. SY5, was isolated from the rhizoplane of barnyard grass (Echinochloa crus-galli) grown in petroleum and heavy-metal-contaminated soil. This isolate has shown capacities for indole acetic acid production and siderophores synthesis. Compared with a non-inoculated control, the radicular root growth of Zea mays seedlings inoculated with SY5 can be increased by 27- or 15.4-fold in the presence of 15 mg-Cd/l or 15 mg-Cu/l, respectively. The results from hydroponic cultures showed that inoculation of Serratia sp. SY5 had a favorable influence on the initial shoot growth and biomass of Zea mays under noncontaminated conditions. However, under Cd-contaminated conditions, the inoculation of SY5 significantly increased the root biomass of Zea mays. These results indicate that Serratia sp. SY5 can serve as a promising microbial inoculant for increased plant growth in heavy-metal-contaminated soils to improve the phytoremediation efficiency.

• Journal of Microbiology and Biotechnology
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• v.7 no.1
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• pp.13-20
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• 1997

Plant growth-promoting Psudomonas fluorescens GL20 was isolated from a ginseng rhizosphere on chrome azurol Sagar. P. fluorescens GL20 produced a large amount of hydoxamate siderophore in an iron-deficient medium. The siderophore showed significantly high specific activity of 20.2 unit. Using an in vitro antifungal test, P. fluorescens GL20 considerably suppressed growth of phytopathogenic fungus Fusarium solani, inhibiting spore germination and germ tube elongation. In pot trials of kidney beans with P. fluorescens GL20, disease incidence was remarkably reduced up to $68{\%}$ compared with that of F. solani alone, and plant growth was also increased nearly 1.6 fold as compared to that of the untreated control, promoting elongation and development of the roots. These results indicate that the plant growth-promoting activity of P. fluorescens GL20 can play an important role in biological control of soil-borne plant disease in a rhizosphere, enhancing the growth of plants.

• Korean Journal of Organic Agriculture
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• v.6 no.1
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• pp.151-160
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• 1997

Azospirillum sp., photosynthetic bacteria(Rhodopseudomonas sp.) and Pseudomonas sp. were separated and screened from soil and soilless culture, and identificated. The antifungal activities against root-infected pathogens and plant growth promoting effects of the cultured solution of the starins(5.0$\times$105 cells/$m\ell$) in the peatmoss compost on the early growth of cucumber and tomato seedling were investigated. Azospirillum sp. and Pseudomonas sp. showed a antifungal activities against Fusarium sp., Pythium sp. and Rhizoctonia sp in thed ranges of 51.0% to 72.0% on potato dextrose agar medium, however photosynthetic bacteria had not antifungal activities. When cultured solution of Azospirillum sp., photosynthetic bacterial and Pseudomonas sp. were bacterialized by mixing with peatmoss compost, early growth of cucumber and tomato in terms of plant height, number of leaves, leaf area, root length, fresh anf dry weight of leaf, stem and root were promoted, especially photosynthetic bacteria had a the best plant growth promting activities.