• Title/Summary/Keyword: Rhizobacterium

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Isolation and Characterization of a N2O-Reducing Rhizobacterium, Pseudomonas sp. M23 from Maize Rhizosphere Soil (옥수수 근권토양으로부터 N2O 환원 근권세균 Pseudomonas sp. M23의 분리 및 특성)

  • Ji-Yoon Kim;Soo Yeon Lee;Kyung-Suk Cho
    • Microbiology and Biotechnology Letters
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    • v.51 no.2
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    • pp.203-207
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    • 2023
  • The N2O-reducing rhizobacterium, Pseudomonas sp. M23, was isolated from maize rhizosphere soil. The maximum N2O reduction rate of the strain M23 was 15.6 mmol·g-dry cell weight-1·h-1. Its N2O reduction activity was not inhibited by diesel contaminant, and it was enhanced by the addition of the root exudates of maize and tall fescue. The remediation efficiency of diesel-contaminated soil planted with maize or tall fescue was not inhibited by inoculating with the strain M23. Root weights in the soil inoculated with the strain M23 were greater than those in the non-inoculated soil. These results suggest that Pseudomonas sp. M23 is a promising bacterium to mitigate N2O emissions during the remediation of diesel-contaminated soil.

Biological Control of Phytopathogenic Fungi by Bacillus amyloliquefaciens 7079; Suppression Rates are Better Than Popular Chemical Fungicides

  • CHUNG SOOHEE;KIM SANG-DAL
    • Journal of Microbiology and Biotechnology
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    • v.15 no.5
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    • pp.1011-1021
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    • 2005
  • Rhizobacteria are actively sought for the substitution of chemical fertilizers and pathogen control agents in environment-friendly sustainable agriculture. To be successfully commercialized in the current Korean market as agriculture biomaterials, microbial agents should exhibit both properties of plant growth promotion and pathogen control. That is, the organism must be a phytostimulator as well as a biocontrol agent. These criteria and the survival rate of a rhizobacterium, Bacillus amyloliquefaciens 7079, in the soil system were investigated to evaluate the suitability for future commercialization. B. amyloliquefaciens 7079-treated seedlings showed $22.8\%$ maximum increase in leaf-length growth, compared with water-treated controls, showing the phytostimulating property. The disease suppression rates of Phytophthora-blight of peppers and Fusarium-wilt of tomatoes by B. amyloliquefaciens 7079 were 1.5 and 2.2 times better, respectively, than by three popular chemical fungicides used in actual agricultural practices to control the respective pathogens. Survival of B. amyloliquefaciens 7079 on the rhizoplane and in the rhizosphere was favorable up to 50 days in the soil system employed. These positive properties show that B. amyloliquefaciens 7079 is likely to be a suitable candidate for commercialization to market as agricultural biomaterials.

A Study on the Effect of the Rhizobacterium, Bacillus sp. SH1RP8 and Potassium Family Polymers on the Crop Growth under Saline (염 환경 하에서 Bacillus sp. SH1RP8와 Polyacrylate Polymers가 작물 생장에 미치는 영향에 관한 연구)

  • Hong, Sun Hwa;Kim, Ji Seul;Park, Jang Woo;Lee, Eun Young
    • KSBB Journal
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    • v.30 no.3
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    • pp.97-102
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    • 2015
  • This study aimed to evaluate the potential plantgrowth promoting effects of potassium polyacrylate, a superabsorbent polymer, and Bacillus sp. SH1RP8, a family of plant-growth-promoting bacteria. Potassium polyacrylate was selected as the polymer for use due to its high molecular weight and its ability to retain and continuously supply moisture. Plant-growth-promoting rhizobacteria (PGPR) were isolated from the soil and applied to plants growing in dry environments, such as saline conditions. The moisture absorption and retention abilities of potassium polyacrylate were evaluated at a high temperature ($50^{\circ}C$) and in a dry condition, during which time the polymer showed a water retention potential of 19606.07% after 29 days. To overcome the reaming problem in the soil environment, natural polymers (such as cellulose) were mixed with the potassium acrylate. The shoot growths of Peucedanum japonicum Thunb and Arundo donax were significantly enhanced when treated with the mixture of the isolated rhizosphere bacterium SH1RP8 and potassium polyacrylate (63.5 and 124.3%, respectively).

Biological Control of Apple Anthracnose by Paenibacillus polymyxa APEC128, an Antagonistic Rhizobacterium

  • Kim, Young Soo;Balaraju, Kotnala;Jeon, Yongho
    • The Plant Pathology Journal
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    • v.32 no.3
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    • pp.251-259
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    • 2016
  • The present study investigated the suppression of the disease development of anthracnose caused by Colletotrichum gloeosporioides and C. acutatum in harvested apples using an antagonistic rhizobacterium Paenibacillus polymyxa APEC128 (APEC128). Out of 30 bacterial isolates from apple rhizosphere screened for antagonistic activity, the most effective strain was APEC128 as inferred from the size of the inhibition zone. This strain showed a greater growth in brain-heart infusion (BHI) broth compared to other growth media. There was a reduction in anthracnose symptoms caused by the two fungal pathogens in harvested apples after their treatment with APEC128 in comparison with non-treated control. This effect is explained by the increased production of protease and amylase by APEC128, which might have inhibited mycelial growth. In apples treated with different APEC128 suspensions, the disease caused by C. gloeosporioides and C. acutatum was greatly suppressed (by 83.6% and 79%, respectively) in treatments with the concentration of $1{\times}10^8$ colony forming units (cfu)/ml compared to other lower dosages, suggesting that the suppression of anthracnose development on harvested apples is dose-dependent. These results indicated that APEC128 is one of the promising agents in the biocontrol of apple anthracnose, which might help to increase the shelf-life of apple fruit during the post-harvest period.