• Applied Biological Chemistry
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• v.41 no.1
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• pp.53-59
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• 1998

The Rhizobium and Azospirillum spp. were isolated from the root nodules of several leguminous plants and rhizosphere of various paddy rice varieties. The growth of the nitrogen-fixing strains isolated was largely inhibited in yeast extract-mannitol medium (AMA) containing 0.6 M NaCl. In response to osmotic stress, the nitrogen-fixing strains accumulate intracellular free glutamate. The growth and nitrogenase activity of Rhizobium and Azospirillum were increased by addition of osmoprotectants such as proline, glycine betaine, and glutamate during salt stress. Glycine betaine was the most effective among exogenous osmoprotectants tested. In the absence of sodium chloride, nitrogenase activity seem to be slightly decreased by the presence of the proline or glycine betaine. These results revealed that nitrogenase activity was repressed by fixed nitrogens such as proline or glycine betaine.

• Journal of Plant Biology
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• v.32 no.3
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• pp.137-144
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• 1989

In order to clarify the effect of the associative nitrogen fixing bacteria on the growth of corn(Zea mays L. Suwon19), we inoculated corn seedlings with Azospirillum amazonense Y1, a micro-aerobic and acid-tolerant nitrogen fixer, and analyzed the growth and dry matter production and changes of nitrogen and phosphorus quantity of the plant during the growing period. The inoculation of associative N-fixing bacgteria increased the growth of height, leaf area, dry weight and total nitrogen quantity of the plant by 15.4%, 65.4%, 33.7% and 38.0%, respectively, on the day of 56th after sowing. Especially the inoculation of A. amazonense Y1 showed two to three-fold accumulation of phosphorus in each organ of plant. The associative bacteria accelerated the growth of the under ground parts more than those of the upper ground parts of corn plant, and caused decrease in T/R ratios.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.249-254
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• 2007

Inoculation dose of agriculturally important microbes is an important criterion that decides the establishment and hence their effects on plant growth. Effects of the inoculation dose of Azospirillum brasilense strain CW903 on the growth and nutrient absorption of three different crops, tomato, rice and red pepper were assessed under green house condition. Three different concentrations of A. brasilense strain CW903 ($10^5$, $10^6$ and $10^8cfu\;mL^{-1}$) were applied through seed treatment and through the soil near the root zone (1 mL per plant) at 20 and 30 days after sowing. Positive effects on the growth of tomato, rice and red pepper were found at $10^6$ and $10^8cfu\;mL^{-1}$ inoculation doses of A. brasilense strain CW903. The inoculation dose of $10^8cfu\;mL^{-1}$ of A. brasilense strain CW903 recorded the best effects on growth parameters like shoot and root length and the absorption of important nutrients.

• Korean Journal of Agricultural Science
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• v.16 no.2
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• pp.163-168
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• 1989

Fourty-four isolates showed acetylene-reducing(nitrogenase)activity under the atmosphere of 89% Ar, 10% $C_2H_2$ and 1 % $O_{2{\cdot}}$, these nitrogen-fixing isolates characterized chemotaxonomically and their taxonomic status was disscussed; twenty-three isolates corresponded to Azospirillum. They were curved/spiral rods, gram negative, motile by a polar flagellum, and also utilized glucose in nitrogen free medild by a polar flagellum, and also utilized glucose in nitrogen free medium. but the cellular fatty acid composition and quinone system of these isolates showed quite different characteristics with reference strains. Therefore, the taxonomic status of this nitrogen-fixing bacteria is disscussed and a new species Azospirillum. Sixty forur isolates utilized C-l compounds such as methanol and formic acid. phenotypic and chemotaxonomic characteristics of methanol utilizing isolates were investigated and their taxonomic status was discussed; Twenty-one isolates corresponded to Hyphomicrobium and for the other regular rods and irregular rods utilizing isolates showed different cellular fatty acid composition. These isolates were grouped into 8 cluster analysis and similarity values based on correlation coefficients. Among these 8 clusters, two corresponded Pseudomonas and for the other were not decided.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.2
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• pp.73-80
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• 2003

An experiment was carried out at the Field Laboratory of the Department of Crop Botany, Bangladesh Agricultural University, Mymensingh from March to July, 2001 to investigate the effect of biofertilizers on morpho-physiological characters of okra. The experiment was laid out in a randomized complete block design with four replications. There were nine treatments such as $\textrm{T}_0$ (control), $\textrm{T}_1$ (Azotobacter biofertilizer), $\textrm{T}_2$ (Azospirillum biofertilizer), $\textrm{T}_3$ (Azotobacter+Azospirillum biofertilizers), $\textrm{T}_4$ (Azotobacter+Cowdung 5 ton $\textrm{ha}^{-1}$), $\textrm{T}_5$ (Azospirillum+Cowdung 5 ton $\textrm{ha}^{-1}$), $\textrm{T}_6$(Azotobacter+Azospirillum+Cowdung 5 ton $\textrm{ha}^{-1}$), $\textrm{T}_7$ (Cowdung 5 ton $\textrm{ha}^{-1}$) and $\textrm{T}_8$ (60% Nitrogen). The experimental results revealed that significant variations exist among the treatments regarding morphological characters e.g. plant height, number of leaves/plant, stem base diameter, tap root length, and physiological characters like, root dry weight, leaf area index and crop growth rate. Number of leaves/plant, stem base diameter, root length, root dry weight, leaf area index and crop growth rate were found higher in $\textrm{T}_4$, $\textrm{T}_5$, $\textrm{T}_6$ and $\textrm{T}_8$ than the others. In all the parameters, $\textrm{T}_8$ gave the similar result with biofertilizers in combination with cowdung treatments and $\textrm{T}_7$ showed identical with $\textrm{T}_0$ (control). Biofertilizer treatments had insignificant effect on 1000-seed weight(g). Experimental results mentioned above revealed that morpho-physioligical characters of okra could be modified by the application of biofertilizer+cowdung. However, biofertilizers+Cowdung treatments were comparable to $\textrm{T}_8$(60% Nitrogen) in this study. This suggests that $\textrm{T}_4$ or $\textrm{T}_6$ or $\textrm{T}_5$ were more benificial in environmentally friendly okra cultivation and may be used as an alternative of inorganic nitrogen by saving cost of production and sustaining productivity.

• 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.

• Korean Journal of Organic Agriculture
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• v.7 no.1
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• pp.129-135
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• 1998

This study was conducted to clarify the plant growth promoting effects of the various rhizobacteria on the growth of hydroponically grown tomatoes in rockwool, perlite and cocopeat cultures. Strains in terms of $Azospirilham\;sp.(4.5{\times}10^7cells/g),\;Rhodopseudomonas\;sp.(5.8{\times}10^5cells/g),\;Pseudomonas\;sp.(6.1{\times}10^6cells/g$), fusant of $Bacillus\;sp.\;and\;Corynebacterium\;glutamicum(9.1{\times}10^5cells/g$) was bacterialized into the root zone of tomatoes before sowing. Overall growth of tomato plants was promoted by bacterialization of the various rhizobacteria. Strains which showed the highest plan growth promoting effects of hydroponically grown tomatoes was Azospirillum sp., and optimum cultural substrates for the plant growth promotion by rhizobactera were in the order of cocopeat > perlite = rockwool cultures.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.4
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• pp.415-427
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• 1984

This experiment was carried out to investigate the distribution of associative nitrogen fixers, Azospirillum spp. and their nitrogenase activities measured by ARA in the rhizosphers of rice, soybean, and weed grown in the rice paddy field at ear formation stage of rice. Nitrogenase activities produced by Azospirillum spp. enriched from histophere ranged from 16 to 53 n mole/tube/hr.. High nitrogen fixing activities more than 30 n mole/tube/hr. were observed in the histophere of the Echinochloa crus-galli L., Finbristylis miliacea L., and Monochoria vaginalis var.. Nitrogen fixing activities of Azospirillum spp. obtained from single colonies which originated from the rhizoplane of rice (pot-kwang var.), Finbris tylis miliacea L., Monochoria vaginaliz var., Glycine max L. were higher over 100 n mole/tube/hr. than those histophere. Genus of Azopsirillum isoltated from roots of the Graminease (Oriza sativa L., $C_3$-plant, Echinochloa crus=galli L., $C_4$-plant, Cyperus difforuis L.. $C_4$-plant), and Aeschynomene indica L. (Leguminosae, $C_3$-plant) was identified as A. brasilense. However, both strains, A. lipoferum and A. brasilense ($nir^-$ or $nir^+$ strain) were isolated from other plant roots, Both $nir^-$ and $nir^+$ strains of A. brasilense were associated with the same host plant.

• The Plant Pathology Journal
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• v.25 no.2
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• pp.199-204
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• 2009

Three plant growth-promoting yeasts and two rhizobacteria were tested for controlling tomato wilt caused by Fusarium oxysporum f. sp. lycopersici under green-house and field conditions. Under greenhouse and field conditions, all treatments were significantly reduced disease severity of tomato wilt relative to the infected control. The highest disease reductions in pots (75.0, 67.4%) and field (52.5, 42.4%) were achieved by Azospirillum brasilense and Bacillus subtilis compared to infected control. Under field condition all treatments produced the highest tomato yield compared to the control plants inoculated with the pathogen.

• Journal of Microbiology and Biotechnology
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• v.32 no.2
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• pp.170-175
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• 2022

3-Hydroxypropionic acid (3HP) is a platform chemical and can be converted into other valuable C3-based chemicals. Because a large amount of glycerol is produced as a by-product in the biodiesel industry, glycerol is an attractive carbon source in the biological production of 3HP. Although eight 3HP-producing aldehyde dehydrogenases (ALDHs) have been reported so far, the low conversion rate from 3-hydroxypropionaldehyde (3HPA) to 3HP using these enzymes is still a bottleneck for the production of 3HP. In this study, we elucidated the substrate binding modes of the eight 3HP-producing ALDHs through bioinformatic and structural analysis of these enzymes and selected protein engineering targets for developing enzymes with enhanced enzymatic activity against 3HPA. Among ten AbKGSADH variants we tested, three variants with replacement at the Arg281 site of AbKGSADH showed enhanced enzymatic activities. In particular, the AbKGSADH^R281Y variant exhibited improved catalytic efficiency by 2.5-fold compared with the wild type.