• Journal of Mushroom
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• v.17 no.2
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• pp.64-69
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• 2019

The present study was conducted to investigate the synergistic effects caused by single and co-inoculation of the phosphate solubilizing bacteria (PSB), Paraburkholderia phenazinium YH3 and Paraburkholderia metrosideri YH4. Phosphate solubilization was assessed by measuring the phosphorus contents for 7 days in a single and co-inoculation medium. Co-inoculation of the two strains was found to release the highest content of soluble phosphorus ($1,250{\mu}g\;mL^{-1}$) into the medium, followed by the single inoculation of P. metrosideri YH4 ($1196.59{\mu}g\;mL^{-1}$) and P. phenazinium YH3 ($994.34{\mu}g\;mL^{-1}$). The highest pH reduction, organic acid production and glucose consumption was also observed in the co-inoculation medium of the two strains. A plant growth promotion bioassay revealed that co-inoculation with the two strains enhanced the growth of romaine lettuce more than single inoculation with either of the two strains (28.5% for leaf and 16.6% for root). Although there was no significant difference between single and co-inoculation of bacterial strains in terms of phosphorous release and plant growth, the synergistic effects of co-inoculation with PSB could be beneficial for crop growth.

• Microbiology and Biotechnology Letters
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• v.14 no.2
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• pp.187-192
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• 1986

The inoculation effect of the highly nitrogen fixing strains of R. japonicum were tested in the 3 kinds of soil with different cultural history onto Gycine max cv. Jang-yeob. The nodulation and nitrogen fixation activity in 3 test soils all showed the great increase in inoculated group compared to the non-inoculated group. The plant dry weight of the in-oculated groups were increased about 10% than that of the non-inoculated groups. The numerical index of the increase in total nitrogen fixation activity were 238% in the pre-cultivated, 266% in the immatured and 157% in the matured soil and these results suggested the clear effect of inoculation. Among the strains tested, R. japonicum R214 and Rl38 showed the excellent inoculation effect.

• Journal of Microbiology and Biotechnology
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• v.22 no.7
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• pp.960-966
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• 2012

The diversity and composition of yeast populations may greatly impact wine quality. This study investigated the yeast microbiota in two different types of wine fermentations: direct inoculation of a commercial starter versus pied de cuve method at an industrial scale. The pied de cuve fermentation entailed growth of the commercial inoculum used in the direct inoculation fermentation for further inoculation of additional fermentations. Yeast isolates were collected from different stages of wine fermentation and identified to the species level using Wallersterin Laboratory nutrient (WLN) agar followed by analysis of the 26S rDNA D1/D2 domain. Genetic characteristics of the Saccharomyces cerevisiae strains were assessed by a rapid PCR-based method, relying on the amplification of interdelta sequences. A total of 412 yeast colonies were obtained from all fermentations and eight different WL morphotypes were observed. Non-Saccharomyces yeast mainly appeared in the grape must and at the early stages of wine fermentation. S. cerevisiae was the dominant yeast species using both fermentation techniques. Seven distinguishing interdelta sequence patterns were found among S. cerevisiae strains, and the inoculated commercial starter, AWRI 796, dominated all stages in both direct inoculation and pied de cuve fermentations. This study revealed that S. cerevisiae was the dominant species and an inoculated starter could dominate fermentations with the pied de cuve method under controlled conditions.

• Research in Plant Disease
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• v.18 no.4
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• pp.331-337
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• 2012

Citrus melanose is one of important disease in citrus cultivation, reducing quality of citrus fruits and resulting in economic loss. Like other diseases in citrus, melanose was mainly protected by chemical fungicide in the field. Recently, alternative method of disease control is highly required due to the side effect of the chemicals. In this study four rhizobacterial strains TRH423-3, MRL408-3, THJ609-3, and TRH415-2 are selected by dual-culture testing its antifungal activity against Diaporthe citri causing citrus melanose. To investigate the protection efficacy of the selected rhizobacterial strains to citrus melanose, the bacteria were pre-treated on citrus leaves following inoculation with melanose pathogen. Pre-treatment with all selected rhizobacterial strains showed disease suppression in which the levels of protection rates were different by the rhizobacterial strains. Additional treatment with the rhizobacterial strains after the pathogen inoculation enhanced protection rates in all cases. The strain MRL408-3 and TRH423-3 were identified as Burkholderia gladioli, TRH415-2 as Pseudomons fluorescens and THJ609-3 as Pseudomonas pudia as a result of analyzing the internal transcript spaces of the rhizobacterial strains rDNA. The selected rhizobacterial strains may be valuable as biological control agents in the environment-friendly citrus farm in which chemical application is limited.

• Journal of Microbiology and Biotechnology
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• v.28 no.7
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• pp.1156-1167
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• 2018

The aim of this study was to isolate and characterize lead (Pb)-solubilizing bacteria from heavy metal-contaminated mine soils and to evaluate their inoculation effects on the growth and Pb absorption of Brassica juncea. The isolates were also evaluated for their plant growth-promoting characteristics as well as heavy metal and salt tolerance. A total of 171 Pb-tolerant isolates were identified, of which only 15 bacterial strains were able to produce clear haloes in solid medium containing PbO or $PbCO_3$, indicating Pb solubilization. All of these 15 strains were also able to dissolve the Pb minerals in a liquid medium, which was accompanied by significant decreases in pH values of the medium. Based on 16S rRNA gene sequence analysis, the Pb-solubilizing strains belonged to genera Bacillus, Paenibacillus, Brevibacterium, and Staphylococcus. A majority of the Pb-solubilizing strains were able to produce indole acetic acid and siderophores to different extents. Two of the Pb-solubilizing isolates were able to solubilize inorganic phosphate as well. Some of the strains displayed tolerance to different heavy metals and to salt stress and were able to grow in a wide pH range. Inoculation with two selected Pb-solubilizing and plant growth-promoting strains, (i.e., Brevibacterium frigoritolerans YSP40 and Bacillus paralicheniformis YSP151) and their consortium enhanced the growth and Pb uptake of B. juncea plants grown in a metal-contaminated soil. The bacterial strains isolated in this study are promising candidates to develop novel microbe-assisted phytoremediation strategies for metal-contaminated soils.

• Korean Journal of Environmental Agriculture
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• v.40 no.1
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• pp.49-59
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• 2021

BACKGROUND: Soil salinity causes reduction of crop productivity. Rhizosphere microbes have metabolic capabilities and ability to adaptation of plants to biotic and abiotic stresses. Plant growth-promoting bacteria (PGPB) could play a role as elicitors for inducing tolerance to stresses in plants by affecting resident microorganism in soil. This study was conducted to demonstrate the effect of selected strains on rhizosphere microbial community under salinity stress. METHODS AND RESULTS: The experiments were conducted in tomato plants in pots containing field soil. Bacterial suspension was inoculated into three-week-old tomato plants, one week after inoculation, and -1,000 kPa-balanced salinity stress was imposed. The physiological and biochemical attributes of plant under salt stress were monitored by evaluating pigment, malondialdehyde (MDA), proline, soil pH, electrical conductivity (EC) and ion concentrations. To demonstrate the effect of selected Bacillus strains on rhizosphere microbial community, soil microbial diversity and abundance were evaluated with Illumina MiSeq sequencing, and primer sets of 341F/805R and ITS3/ITS4 were used for bacterial and fungal communities, respectively. As a result, when the bacterial strains were inoculated and then salinity stress was imposed, the inoculation decreases the stress susceptibility including reduction in lipid peroxidation, enhanced pigmentation and proline accumulation which subsequently resulted in better plant growth. However, bacterial inoculations did not affect diversity (observed OTUs, ACE, Chao1 and Shannon) and structure (principle coordinate analysis) of microbial communities under salinity stress. Furthermore, relative abundance in microbial communities had no significant difference between bacterial treated- and untreated-soils under salinity stress. CONCLUSION: Inoculation of Bacillus strains could affect plant responses and soil pH of tomato plants under salinity stress, whereas microbial diversity and abundance had no significant difference by the bacterial treatments. These findings demonstrated that Bacillus strains could alleviate plant's salinity damages by regulating pigments, proline, and MDA contents without significant changes of microbial community in tomato plants, and can be used as effective biostimulators against salinity stress for sustainable agriculture.

• The Journal of the Korean Society for Microbiology
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• v.34 no.5
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• pp.471-478
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• 1999

Spirochetes were isolated from the midgut of Ixodes persulcatus ticks captured at Chungju, Korea and identified as Borrelia afzelii strains by polymerase chain reaction. To determine the pathogenicity of the B. afzelii strains isolated in Korea, the microbiological and pathological features of Lyme disease were observed in C3H/He mice after intraperitoneal inoculation of the fresh isolate of B. afzelii strain. The results are summarized as follows 1) The Borrelia were detected in the tissues of heart, spleen, kidney, urinary bladder and knee joint within 7 days after inoculation of infection by dark field microscopic examination. The isolation rate from heart, urinary bladder and joint was significantly higher than the rate from spleen, kidney, and blood samples. 2) The Borrelia was detected in heart muscle by indirect immunofluorescent antibody test. 3) Antibody to the Borrelia was detected as early as one week after inoculation. 4) The marked tropism of the Borrelia was observed in myocardial, urinary tract and joint tissue. The main pathological features are inflammation in tissues of heart, kidney, joint and urinary bladder. From these results, the Borrelia afzelii strain isolated in Korea were determined as pathogenic strain.

• Journal of Mushroom
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• v.15 no.4
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• pp.183-189
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• 2017

This study investigated the synergistic effect of single inoculation and co-inoculation of phosphate-solubilizing bacteria (PSB) Burkholderia metallica JH-7 and Burkholderia contaminans JH-15. Phosphate-solubilizing abilities of these strains were assessed by measuring phosphorus content in culture media that were singly inoculated or co-inoculated with these strains for 7 days. B. metallica JH-7 was found to release the highest content of soluble phosphorus ($140.80{\mu}g\;mL^{-1}$ ) into the medium, followed by single inoculation of B. contaminans JH-15 ($135.95{\mu}g\;mL^{-1}$ ) and co-inoculation of two strains ($134.84{\mu}g\;mL^{-1}$ ). The highest pH reduction, organic acid production, and glucose consumption were observed in the medium inoculated with B. metallica JH-7 alone compared with that in the medium co-inoculated with both the strains. Results of a plant growth promotion bioassay showed 17.4% and 7.48% higher leaf and root growth, respectively, in romaine lettuce inoculated with B. metallica JH-7 alone than in romaine lettuce inoculated with a control strain. However, no significant difference was observed between single inoculation and co-inoculation of these strains with respect to phosphorus release and plant growth. Although the results of the present study did not show the synergistic effect of phosphate solubilization by the PSB strains examined, these results indicate that treatment with PSB exerts a beneficial effect on crop growth.

• Entomological Research
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• v.48 no.5
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• pp.339-347
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• 2018

Seven different strains of Beauveria bassiana were used in a bioassay on Pieris rapae larvae. The results showed that an B. bassiana strain showed relatively high pathogenicity towards P. rapae larvae. The adjusted mortality rate was 92.86 %, and the infection rate was 85.71 % in 10 days post inoculation. Molecular identification was performed to identify the unknown strain. Internal Transcribed Spacer sequence analysis showed that the polymerase chain reaction amplicon length of the unknown strain of Beauveria sp. was 573 bp, and sequence similarity to the known B. bassiana sequences in the NCBI database was 99 %. The B. bassiana strain was named Bb01. The changes of proteins and PPO of P. rapae larvae infected by B. bassiana Bb01 strain at different times was determined. The activity of PPO increased in 1-6 d and decreased in 7 d again after inoculation. The B. bassiana invaded into the insect body affected the balance of the proteins and PPO.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.2
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• pp.181-188
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• 1992

This study was carried out to evaluate the fate of inoculant Bradyrhizobium japonicum and the inoculation effect on soybean in complex soil environment. To moniter Rhizobium strains from the root, streptomycine and streptomycine and nalidixic acid resistant marker strains were prepared by spontaneous mutagenesis. The characteristics and properties of antibiotic marked strains were not altered by the mutagenesis. The comparison of properties of wild type and antibiotic resistant Bradyrhizobium strains are summarized as follow : 1) The strains of USDA110K-$STR^r$, USDA110N-$STR^r$ and R318-$STR^r$ showed weak tolerance to pH 9.0. The utilization of carbon sources by fast growing group was different from that of slow growing group. The marked strains of R214-$STR^rNAL^r$, USDA110K-$STR^r$ and USDA110N-$STR^r$ was doubtful in utilization of sorbitol and R138-$STR^rNAL^r$ was doubtful in utilization of xylose as a carbon source. 2) By examining the agglutination reaction of serogroups, the strains used were identified as different ones. There were no differences between wild type and marked strains in agglutination titer values. 3) The plasmid size of fast group was slightly greater than that of slow group. However, there was no differences in plasmid size between the wild type and antibiotic resistant strains. This result indicates that the antibiotic resistance was not encoded in plasmid. 4) The recovery of the inoculated strains was up to 12.5 % in soybean cultivated soil and was up to 25 % in soybean uncultivated soil. 5) When the wild type or marked strains were inoculated. there was no significant effect on soybean plant, whereas the inoculation effect was pronounced in soybean uncultivated soil. The inoculation effect seemed to be more pronounced in wild type strains than antibiotic resistant strains. however, the difference was not significant.