• Korean Journal of Soil Science and Fertilizer
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• v.43 no.1
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• pp.96-104
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• 2010

A comparative study was performed in gnotobiotic and greenhouse conditions to evaluate the effect of exogenous application of indole-3-acetic acid (IAA) and inoculation of Methylobacterium spp. possessing 1-aminocyclopropane-1-carboxylate deaminase (ACCD) and IAA activity on red pepperand tomato seedling growth and development. Application of 1.0 ${\mu}g\;mL^{-1}$ IAA positively influenced root growth while high concentrations (>10.0 ${\mu}g\;mL^{-1}$) suppressed root growth of red pepper and tomato under gnotobiotic condition. On the other hand, inoculation of Methylobacterium strains with ACCD activity and IAA or without IAA enhanced root growth in both plants. Similarly, under greenhouse condition the inoculation of Methylobacterium sp. with ACCD activity and IAA enhanced plant fitness recorded as average nodal length and specific leaf weight (SLW) but the effect is comparable with the application of low concentrations of IAA. Seedling length was significantly increased by Methylobacterium strains while total biomass was enhanced by Methylobacterium spp. and exogenous applications of < 10.0 ${\mu}g\;mL^{-1}$ IAA. High concentrations of IAA retard biomass accumulation in red pepper and tomato. These results confirm that bacterial strains with plant growth promoting characters such as IAA and ACCD have characteristic effects on different aspects of growth of red pepper and tomato seedlings which is comparable or better than exogenous applications of synthetic IAA.

• Journal of Microbiology and Biotechnology
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• v.16 no.10
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• pp.1622-1628
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• 2006

Bacteria from the Methylobacterium genus, called pink-pigmented facultative methylotrophic bacteria (PPFMs), are common inhabitants of plants, potentially dominating the phyllosphere population, and are also encountered in the rhizosphere, seeds, and other parts of plants, being versatile in nature. The consistent success of the Methylobacterium plant association relies on methylotrophy, the ability to utilize the one-carbon compound methanol emitted by plants. However, the efficiency of Methylobacterium in plant growth promotion could be better exploited and thus has attracted increasing interest in recent years. Accordingly, the present study investigated the inoculation effects of Methylobacterium sp. strains CBMB20 and CBMB 110 on seed imbibition to tomato and red pepper on the growth and accumulation of phytohormone levels under gnotobiotic conditions. Seeds treated with the Methylobacterium strains showed a significant increase in root length when compared with either the uninoculated control or Methylobacterium extorquens $miaA^-$ knockout mutanttreated seeds. Extracts of the plant samples were used for indole-3-acetic acid (IAA), trans-zeatin riboside (t-ZR), and dihydrozeatin riboside (DHZR) assays by immunoanalysis. The treatment with Methylobacterium sp. CBMB20 or CBMB 110 produced significant increases in the accumulation of IAA and the cytokinins t-ZR and DHZR in the red pepper extracts, whereas no IAA was detected in the tomato extracts, although the cytokinin concentrations were significantly increased. Therefore, this study proved that the versatility of Methylobacterium as a plant-growth promoting bacteria could be better exploited.

• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.94-99
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• 1991

- The further study for the identification of the previously reported pink-pigmented facultative methylotrophic bacterium (PPFM) GL-10 was carried out. The PPFM GL-10 was Gram nagative, rod, and motile by a single polarly inserted flagellum. The colonies were smooth, pink, circular, along with convex with entire margin. The isolate could utilize C1 compounds and a variety of multicarbon substrates as sole carbon and energy source. The isolate was obligately aerobic, and exhibited both catalase and oxidase activities. The deoxyribonucleic acid base composition was 65-67 mol% guanine plus cytosine. The isolate was mostly identical with Methylobacterium extorquens and named Methylobacterium sp. strain GL-10. Methylobacterium GL-10 accumulated a copolyester of 3-hydroxybutyrate and 3-hydroxyvalerate (poly-3HB/3 HV) when grown in nitrogen-free culture media containing sodium propionate as substrate at the second polyester accumulation stage. The composition of copolyester, as determined from $^1h$ NMR spectra, was 23 mol% of 3-hydroxyvalerate (3HV).

• Microbiology and Biotechnology Letters
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• v.35 no.1
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• pp.58-65
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• 2007

The role of soil microorganisms, specifically rhizobacteria, in the development of rhizoremediation techniques is important to speed up the process and to increase the rate of mobilization or absorption of heavy metals to the plant. In this study, Methylobacterium sp. SY-NiR1 was isolated from the rhizosphere soils of plants in oil and heavy metal-contaminated soil. Based on its pink pigmented colony, rod-shape cells, and belonging in $\alpha-Proteobacteria$, Methylobacterium sp. SY-NiR1 is considered a pink-pigmented facultative methylotroph. SY-NiR1 had the ability to produce indole acetic acid which is one of phytohormones. This bacterium showed resistance against multiple heavy metals such as Cd, Cr, Cu, Pb, Ni, Zn, and the order of its resistance based on $EC_{50}$ was Zn > Ni > Cu > Pb > Cd > Cr. Therefore, Methylobacterium sp. SY-NiR1 can stimulate seed germination and plant growth in soil contaminated with heavy metals.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.812-816
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• 2016

We isolated a novel methylotrophic bacterium from soil collected in Dongducheon Environment Affairs Agency. The isolate was identified as Methylobacterium sp. WJ4 based on phylogenetic analysis. Plackett-Burman design was employed for screening eight parameters of nitrate mineral salts (NMS) medium for cell growth of a newly isolated Methylobacterium sp. WJ4 with experimental validation. Trace element solution and vitamin stock were found to affect cell growth, which can be further optimized for increased cell growth. This is the first report of screening parameters of NMS medium which affect cell growth of strain belonging to the genus Methylobacterium using Plackett-Burman design.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.37-42
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• 2012

Improvement of plant growth by Methylotrophic bacteria can be influenced through alterations in growth modulating enzymes or hormones, especially by decreasing ethylene levels enzymatically by 1-aminocyclopropane-1-carboxylate (ACC) deaminase or by production of indole-3-acetic acid (IAA). In this study, the effect of seven strains of Methylobacterium on seedling ethylene emission of tomato and red pepper plants was evaluated under greenhouse condition. Ethylene emission was lowest in Methylobacterium oryzae CBMB20 inoculated tomato plants and CBMB110 inoculated red pepper plants at 47 days after sowing (DAS). However, at 58 DAS all inoculated plants showed almost similar pattern of ethylene emission. Methylobacterium inoculated tomato and red pepper plants showed significantly less ethylene emission compared to control. Our results demonstrated that Methylobacterium spp. inoculation promotes plant growth due to the reduction of ethylene emission and therefore can be potentially used in sustainable agriculture production systems.

• Journal of Microbiology and Biotechnology
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• v.17 no.2
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• pp.226-233
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• 2007

Members of Methylobacterium, referred as pink-pigmented facultative methylotrophic bacteria, are frequently associated with terrestrial and aquatic plants, tending to form aggregates on the phyllosphere. We report here that the production of autoinducer molecules involved in the cell-to-cell signaling process, which is known as quorum sensing, is common among Methylobacterium species. Several strains of Methylobacterium were tested for their ability to produce N-acyl-homoserine lactone (AHL) signal molecules using different indicators. Most strains of Methylobacterium tested could elicit a positive response in Agrobacterium tumefaciens harboring lacZ fused to a gene that is regulated by autoinduction. The synthesis of these compounds was cell-density dependent, and the maximal activity was reached during the late exponential to stationary phases. The bacterial extracts were separated by thin-layer chromatography and bioassayed with A. tumefaciens NTI (traR, tra::lacZ749). They revealed the production of various patterns of the signal molecules, which are strain dependent. At least two signal molecules could be detected in most of the strains tested, and comparison of their relative mobilities suggested that they are homologs of N-octanoyl-$_{DL}$-homoserine lactone ($C_8-HSL$) and N-decanoyl-$_{DL}$-homoserine lactone ($C_{10}-HSL$).

• Korean Journal of Environmental Agriculture
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• v.41 no.2
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• pp.115-124
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• 2022

BACKGROUND: Methane is a major greenhouse gas attributed to global warming partly contributed by agricultural activities from ruminant fermentation and rice paddy fields. Methanotrophs are microorganisms that utilize methane. Their unique metabolic lifestyle is enabled by enzymes known as methane monooxygenases (MMOs) catalyzing the oxidation of methane to methanol. Rice absorbs, transports, and releases methane directly from soil water to its stems and the micropores and stomata of the plant epidermis. Methylobacterium species associated with rice are dependent on their host for metabolic substrates including methane. METHODS AND RESULTS: Methylobacterium spp. isolated from rice were evaluated for methane oxidation activities and screened for the presence of sMMO mmoC genes. Qualitatively, the soluble methane monooxygenase (sMMO) activities of the selected strains of Methylobacterium spp. were confirmed by the naphthalene oxidation assay. Quantitatively, the sMMO activity ranged from 41.3 to 159.4 nmol min^-1 mg of protein^-1. PCR-based amplification and sequencing confirmed the presence and identity of 314 bp size fragment of the mmoC gene showing over 97% similarity to the CBMB27 mmoC gene indicating that Methylobacterium strains belong to a similar group. CONCLUSION(S): Selected Methylobacterium spp. contained the sMMO mmoC gene and possessed methane oxidation activity. As the putative methane oxidizing strains were isolated from rice and have PGP properties, they could be used to simultaneously reduce paddy field methane emission and promote rice growth.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.4
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• pp.317-322
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• 2009

Healthy seedling generation is the major concern in overcoming adverse effects of biotic and abiotic stresses during tender stage of development in vegetables and horticultural crops. Because of this, priority is given to research leading to the generation of healthy seedlings in crops subjected to transplanting and bedding. In this study, growth pouch experiments were conducted to determine the effect of inoculation of six different strains of Methylobacterium sp. namely, M. oryzae CBMB20, M. phyllosphaerae CBMB27, M. suomiense CBMB120, and Methylobacterium strains CBMB12, CBMB15 and CBMB17 on the seedling development of the vegetable crops cabbage, Chinese cabbage and cucumber; and horticultural crops tomato and red pepper. Crops treated with the test strains generally showed higher seedling dry matter accumulation compared to the control. Significantly higher accumulation was exhibited by CBMB12, CBMB17, and CBMB20 in cabbage, as well as for CBMB27 and CBMB120 on tomato and Chinese cabbage, respectively. Furthermore, all the strains promoted root elongation in cucumber and tomato seedlings while in Chinese cabbage and red pepper, root elongation was observed with CBMB120 and CBMB12 inoculation, respectively. Large scale nursery study is needed to develop a thorough protocol for healthy seedling development with the use of these strains.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.719-721
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• 2016

Formate has been considered as an environmentally sustainable feedstock that can be used to accelerate the production of valuable chemicals. This study presents brief results of the formatotrophic production of Poly-${\beta}$-hydroxybutyric acid (PHB) by Methylobacterium sp. To evaluate the production of PHB, five species of Methylobacteria were tested using formate as the sole carbon and energy source. Methylobacterium chloromethanicum CM4 exhibited the highest productivity of PHB, which showed 1.72 g/L PHB production, 32.4% PHB content, and 0.027 g-PHB/g-formate PHB yield. These results could be used for the formatotrophic production of PHB with the concurrent reduction of $CO_2$ to formate.