• The Plant Pathology Journal
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• v.24 no.1
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• pp.67-73
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• 2008

Seedling damping-off and bottom rot caused by Rhizoctonia solani are yield limiting diseases of crisphead lettuce. To provide biocontrol measure in the management of the diseases, biocontrol strain Pseudomonas aeruginosa LY-11 was isolated from lettuce rhizosphere and introduced into crisphead lettuce rhizosphere by the seed coating delivery method. Alginate was used as a coating material to generate beads containing $10^6-10^{6.5}$ colony-forming units (CFUs) of viable bacterial cells of LY-11. When seeds germinated from the alginate beads containing the strain LY-11, the bacteria established mostly in plant rhizosphere to maintain at least $10^4$ CFU per gram of plant tissues. Crisphead lettuce seedlings germinated from the entrapped seeds were less affected from damping-off and bottom rot with disease control values of 70.4% and 85.4% respectively. Although P. aeruginosa LY-11 colonized plant rhizosphere and not phyllosphere, the result indicated that bottom rot caused by the foliar inoculation of R. solani was effectively reduced by the rhizobacteria. All data suggested that immobilized rhizobacterial application in seeds by alginate coating could control damping-off and induce induced systemic resistance of crisphead lettuce to reduce bottom rot.

• Food Science of Animal Resources
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• v.34 no.4
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• pp.543-551
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• 2014

The aim of this study was to evaluate the effect of proteolytic (Serratia liquefaciens, match %: 99.39) or lipolytic (Acinetobacter genomospecies 10, match %: 99.90) psychrotrophic bacteria (bacterial counts, analysis of free fatty acids (FFA) and analysis of free amino acids) on the microbial and chemical properties (yogurt composition), and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of yogurt during storage. Yogurts were prepared with raw milk preinoculated with each psychrotrophic bacteria. The total solid, fat, and protein content were not affected by preinoculation, but the pH of yogurt preinoculated with psychrotrophic bacteria was higher than in control. There was a dramatic increase in short chain free fatty acids among FFA in yogurt with Acinetobacter genomospecies 10. For 14 d of cold storage condition, SCFFA was 25.3 mg/kg to 34.4 mg/kg (1.36 times increased), MCFFA was 20.4 mg/kg to 25.7 mg/kg (1.26 times increased), and LCFFA was 240.2 mg/kg to 322.8 mg/kg (1.34 times increased). Serratia liquefaciens (match %: 99.39) in yogurt caused a greater accumulation of free amino acids (FAA), especially bitter peptides such as leucine, valine, arginine, and tyrosine, but SDS-PAGE showed that the inoculation of Serratia liquefaciens did not affect the degree of casein degradation during storage. Taken together, the excessive peptides and FFA in yogurt generated from psychrotrophic bacteria could develop off-flavors that degrade the quality of commercial yogurt products.

• The Plant Pathology Journal
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• v.19 no.5
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• pp.239-247
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• 2003

In Korea, a local soybean (Glycine max) genotype 56l. was found to be strongly resistant to a virulent bacterial strain of a Pseudomonas sp. SN239. Specific genes involved in the resistance of the soybean genotype 561 were identified and the pattern of gene expression against the Pseudomonas infection was analyzed using differential-display reverse transcription PCR (DDRT-PCR). More than 126 cDNA fragments representing mRNAs were induced within 48 hours of bacteria inoculation. Among them, 28 cDNA fragments were cloned and sequenced. Twelve differentially displayed clones with open reading frames had unknown functions. Sixteen selected cDNA clones were homologous to known genes of other organisms. Some of the identified cDNAs were pathogenesis-related (PR) genes and PR-like genes. These cDNAs included a putative calmodulin-binding protein; an endo-l,3-1,4-$\bate$-D-glucanase; a $\bate$-1,3-endoglucanase; a $\bate$-1,3-exoglucanase; a phytochelatin synthetase-like gene; a thiol protease; a cycloartenol synthase; and a putative receptor-like serine/threonine protein kinase. Among them, four genes were found to be putative PR genes induced significantly by the Pseudomonas infection. These included a calmodulin-binding protein gene, a $\bate$-1,3-endoglucanase gene, a receptor-like serine/threonine protein kinase gene, and pS321 (unknown function). These results suggest that the differentially expressed genes may mediate the strong resistance of soybean 561 to the strain SN239 of Pseudomonas sp.

• The Plant Pathology Journal
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• v.32 no.4
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• pp.300-310
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• 2016

Pathogen infection in plants induces complex responses ranging from gene expression to metabolic processes in infected plants. In spite of many studies on biotic stress-related changes in host plants, little is known about the metabolic and phenotypic responses of the host plants to Pseudomonas cichorii infection based on image-based analysis. To investigate alterations in tomato plants according to disease severity, we inoculated plants with different cell densities of P. cichorii using dipping and syringe infiltration methods. High-dose inocula (${\geq}10^6cfu/ml$) induced evident necrotic lesions within one day that corresponded to bacterial growth in the infected tissues. Among the chlorophyll fluorescence parameters analyzed, changes in quantum yield of PSII (${\Phi}PSII$) and non-photochemical quenching (NPQ) preceded the appearance of visible symptoms, but maximum quantum efficiency of PSII ($F_v/F_m$) was altered well after symptom development. Visible/near infrared and chlorophyll fluorescence hyperspectral images detected changes before symptom appearance at low-density inoculation. The results of this study indicate that the P. cichorii infection severity can be detected by chlorophyll fluorescence assay and hyperspectral images prior to the onset of visible symptoms, indicating the feasibility of early detection of diseases. However, to detect disease development by hyperspectral imaging, more detailed protocols and analyses are necessary. Taken together, change in chlorophyll fluorescence is a good parameter for early detection of P. cichorii infection in tomato plants. In addition, image-based visualization of infection severity before visual damage appearance will contribute to effective management of plant diseases.

• Korean Journal of Organic Agriculture
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• v.25 no.2
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• pp.461-473
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• 2017

Total mixed ration (TMR) including concentrate diet and roughage together have been used for the ruminant animal. Relatively high concentrations of moisture and water soluble carbohydrate are representative feature of TMR. Those moisture and water can also provide a niche for bacterial growth. Therefore, a possible fermentation of TMR induced by micro-organism is generally accepted. The present study hypothesized that different lactic acid bacteria could alter fermentation of TMR and subsequently rumen fermentation. Three lactic acid bacteria, Lactobacillus paracasei (A), L. plantarum (B) and L. parabuchneri (C), were employed and 7 treatments under full factorial design were compared with control without inoculation. TMR for dairy cow was used. Significant alterations by treatments were detected at lactic acid and butyric acid contents in TMR (p<0.05). Treatment AC (mixture of A and C) and BC (mixture of B and C) showed great lactate production. Great butyrate production was found at treatment C. At in vitro rumen fermentation, treatments B, C and AB (mixture of A and B) showed significantly great total gas production (p<0.05). All treatments except treatments B and AB, showed less dry matter digestibility, significantly (p<0.05). Total volatile fatty acid production at treatment AC was significantly greater than others (p<0.05). In individual volatile fatty acid production, treatment AB and AC showed great acetate and propionate productions, significantly (p<0.05). This study investigated correlation between organic acid production in TMR and rumen volatile fatty acid production. And it was found that butyric acid in TMR had significant negative correlation with acetate, propionate, total volatile fatty acid, AP ratio and dry matter digestibility.

• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.3
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• pp.201-206
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• 2015

An experiment was carried out to determine the homofermentative activity of Lactobacillus plantarum KCC-10 and KCC-19 on the ensiling of whole crop barley (WCB). The crude protein in the silages was slightly higher in the KCC-10 and KCC-19 treatments compared to the control, but there was no significant difference between the two inoculant-treated silages. Nutrient parameters such as acid detergent fiber, neutral detergent fiber and in vitro dry matter digestibility in L. plantarum KCC-10 and KCC-19 treated silages did not differ from those in the control silage. The lactic acid content increased in KCC-10 and KCC-19 treated silage when compared with the control silage but the contents of acetic acid and butyric acid produced in KCC-10 and KCC-19 treated silages were similar with the control silage. Further, the number of lactic acid bacteria (LAB) in KCC-10 treated silage demonstrated a significant increase when compared to the control. Especially, KCC-19 treated silage showed greater lactic acid bacterial growth potential. Other microbes such as yeast and fungi were not detected in KCC-10 and KCC-19 treated WCB silages. Hence, this study suggests that the addition of L. Plantarum KCC-10 and KCC-19 to the WCB silage can improve fermentation quality for the production of high-quality silage.

• Preventive Nutrition and Food Science
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• v.18 no.2
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• pp.104-110
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• 2013

Presence of Helicobacter pylori is associated with an increased risk of developing upper gastrointestinal tract diseases. Antibiotic therapy and a combination of two or three drugs have been widely used to eradicate H. pylori infections. Due to antibiotic resistant drugs, new drug resources are needed such as plants which contain antibacterial compounds. The aim of this study was to investigate the ability of GutGard$^{TM}$ to inhibit H. pylori growth both in Mongolian gerbils and C57BL/6 mouse models. Male Mongolian gerbils were infected with the bacteria by intragastric inoculation ($2{\times}10^9$ CFU/gerbil) 3 times over 5 days and then orally treated once daily 6 times/week for 8 weeks with 15, 30 and 60 mg/kg GutGard$^{TM}$. After the final administration, biopsy samples of the gastric mucosa were assayed for bacterial identification via urease, catalase and ELISA assays as well as immunohistochemistry (IHC). In the Mongolian gerbil model, IHC and ELISA assays revealed that GutGard$^{TM}$ inhibited H. pylori colonization in gastric mucosa in a dose dependent manner. The anti-H. pylori effects of GutGard$^{TM}$ in H. pylori-infected C57BL/6 mice were also examined. We found that treatment with 25 mg/kg GutGard$^{TM}$ significantly reduced H. pylori colonization in mice gastric mucosa. Our results suggest that GutGard$^{TM}$ may be useful as an agent to prevent H. pylori infection.

• Applied Biological Chemistry
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• v.28 no.2
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• pp.92-97
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• 1985

UV irradiation method was applied to Agrobacterium tumefaciens A 136 to obtain arginine auxotrophic mutant which is applicable as a host of Ti-plasmid. When the bacterial growth was measured at 600 nm, it showed the exponential phase between 7 and 16 hours after 2% inoculation (v/v) in TY medium and the generation time of 4.8 hours. Survival rate of $1{\sim}0.1%$ was reserved when irradiated at the intensity of $800\;{\mu}w/cm^2$ for $30{\sim}50sec$. Fifteen mutants were selected among 5,000 colonies after UV irradiation. Two of them were identified as arginine auxotrophs, three of them as asparagine auxotrophs, ana the other not as arginine, asparagine, glycine nor cysteine auxotrophs.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.3
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• pp.213-216
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• 2014

Arsenic is a known hazardous metalloid not only to the animals but also to plants. With high concentrations, it can impede normal plant growth and cause even death of plants at extremely high levels. A known plant response to stress conditions such as toxic levels of metal (loids) is the production of stress ethylene, causing inhibitory effect on root growth in plants. When the effect of various arsenic concentrations was tested to maize plant, the stress ethylene emission proportionately increased with increasing concentration of As(V). The inoculation of two arsenic tolerant bacteria; Pseudomonas grimonti JS126 and Pseudomonas taiwanensis JS238 having respective high and low 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity reduced stress ethylene emission by 59% and 30% in maize grown in arsenic polluted soils. The result suggested the possible use of Pseudomonas grimonti JS126 for phytoremediation of arsenic polluted soils.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.3
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• pp.141-146
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• 2014

The necessity to develop economical and eco-friendly technologies is steadily increasing. Plant growth promoting rhizomicrobial strains PGPR are a group of microorganisms that actively colonize plant roots and increase plant growth and yield. Pot experiments were used to investigate the potential of some rhizobacterial strains to enhance the Brassica rapa growth. Microbial strains were successfully isolated from the rhizosphere of Panax ginseng and characterized based on its morphological and plant growth promotion characters. Surface disinfected seeds of Wisconsin Fast B. rapa were inoculated with the selected PGPR microorganisms. The different pots treatments were inoculated by its corresponding PGPR ($10^7cfu\;mL^{-1}$) and incubated in the growth chamber at $25^{\circ}C$ and 65% RH, the light period was adjusted to 24 hours (day). NPK chemical fertilizer and trade product (EMRO, USA) of effective microorganisms as well as un-inoculated control were used for comparison. Plants harvested in 40 days were found to have significant increase in leaf chlorophyll units and plant height and also in dry weight of root and shoot in the inoculated seedlings. Root and shoot length and also leaf surface area significantly were increased by bacterial inoculation in sterile soil. The study suggests that Rhodobacter capsulatus and Azotobacter chroococcum are beneficial for B. rapa growth as they enhance growth and induced IAA production and phosphorus solubilization. This study presents some rhizomicrobial strains that significantly promoted growth of Wisconsin Fast Plant B. rapa in pot experiment under different soil conditions.