• Journal of Microbiology and Biotechnology
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• 제30권8호
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• pp.1169-1179
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• 2020

In this study, two soybean genotypes, i.e., aluminum-tolerant Baxi 10 (BX10) and aluminumsensitive Bendi 2 (BD2), were used as plant materials and acidic red soil was used as growth medium. The soil layers from the inside to the outside of the root are: rhizospheric soil after washing (WRH), rhizospheric soil after brushing (BRH) and rhizospheric soil at two sides (SRH), respectively. The rhizosphere bacterial communities were analyzed by high-throughput sequencing of V4 hypervariable regions of 16S rRNA gene amplicons via Illumina MiSeq. The results of alpha diversity analysis showed that the BRH and SRH of BX10 were significantly lower in community richness than that of BD2, while the WRH exhibited no significant difference between BX10 and BD2. Among the three sampling compartments of the same soybean genotype, WRH had the lowest community richness and diversity while showing the highest coverage. Beta diversity analysis results displayed no significant difference for any compartment between the two genotypes, or among the three different sampling compartments for any same soybean genotype. However, the relative abundance of major bacterial taxa, specifically nitrogen-fixing and/or aluminum-tolerant bacteria, was significantly different in the compartments of the BRH and/or SRH at phylum and genus levels, indicating genotype-dependent variations in rhizosphere bacterial communities. Strikingly, as compared with BRH and SRH, the WRH within the same genotype (BX10 or BD2) always had an enrichment effect on rhizosphere bacteria associated with nitrogen fixation.

• 한국토양비료학회지
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• 제20권2호
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• pp.185-192
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• 1987

담수상태(湛水狀態)의 논토양(土壤)에서 광합성미생물(光合成微生物) 및 타양성미생물(他養性微生物)에 의한 질소고정력(窒素固定力)을 알기 위하여 우리나라 전국(全國) 수도(水稻) 삼요소시비량시험지(三要素施肥量試驗地) 16개소(個所)의 무질소구(無窒素區) 표토(表土)를 채취(採取)하여 초자실(硝子室)에서 항온(恒溫)하면서 토양통(土壤統), 농업기후대(農業氣候帶), 논토양유형(土壤類型), 토성(土性) 및 배수정도(排水程度)에 따른 질소고정량(窒素固定量) 차이조사(差異調査)를 한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 담수항온기간중(湛水恒溫期間中) 광합성질소고정미생물(光合成窒素固定微生物)에 의한 Acetylene 환원력(還元力)은 항온(恒溫) 7일째, 그리고 타양성질소고정미생물(他養性窒素固定微生物)에 의한 Acetylene 환원력(還元力)은 항온(恒溫) 35일째 가장 높았다. 2. 타양성미생물(他養性微生物)에 의한 질소고정력(窒素固定力)이 가장 높은 토양통(土壤統)은 장계(長溪), 옥천(沃泉) 및 화동통(華東統)이었으며 질소고정력(窒素固定力)이 낮은 토양(土壤)은 부용(芙蓉) 및 대정통(大靜統)이었다. 광합성미생물(光合成微生物)에 의한 질소고정력(窒素固定力)이 가장 높은 토양(土壤)은 대정(大靜) 및 지산통(芝山統)이였으며 낮은 토양(土壤)은 장계(長溪), 함창통(咸昌統)이였다. 3. 항온(恒溫) 105 일간(日間) Acetylene 환원법(還元法)에 의한 생물질소고정량(生物窒素固定量)은 광합성미생물(光合成微生物)에 의하여 3.0mg, 그리고 타양성미생물(他養性微生物)에 의하여 4.9mg/100g이었다. 4. 농업기후대별(農業氣候帶別) 생물질소고정량(生物窒素固定量)은 광합성미생물(光合性微生物)의 경우 기온(氣溫)이 온난(溫暖)한 남부해안지역(南部海岸地域)에서 높고 타양성미생물(他養性微生物)은 산간지(山間地)와 충청내륙지역(忠淸內陸地域)에서 높았다. 5. 답토양유형별(沓土壤類型別) 질소고정량(窒素固定量)은 광합성미생물(光合成微生物)의 경우 보통답(普通沓) 토양(土壤)에서 높고 타양성미생물(他養性微生物)의 경우는 조립질(粗粒質)의 사질답(砂質畓) 토양(土壤)에서 높았다. 6. 토양(土壤)의 특성별(特性別) 질소고정력(窒素固定力)을 볼 때 광합성미생물(光合成微生物)은 배수(排水) 약간불량(若干不良)한 식질(埴質) 혹(或)은 식양질토양(埴壤質土壤)에서 높고 타양성미생물(他養性微生物)은 배수양호(排水良好)한 사질토양(砂質土壤)에서 높았다.

• 한국미생물·생명공학회지
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• 제47권3호
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• pp.390-400
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• 2019

본 연구에서 부산, 창원, 제주도 일대에서 채취한 토양으로부터 분리한 미생물을 이용하여 식물 생장 촉진활성 및 식물병원성 곰팡이에 대한 길항능을 확인하고자 하였으며, 분리주 간에 비교우위를 통해 Pseudomonas plecoglossicida ANG14, Pseudarthrobacter equi ANG28, Beijerinckia fluminensis ANG34, Acinetobacter calcoaceticus ANG35를 최종 선정하였다. 이들은 ACC deaminase 생성능, IAA 생성능, 질소 고정능, 인산 가용화능 및 siderophore 생성능을 모두 가지며, 일부 식물병원성 곰팡이에 대해 길항능을 가지는 것을 확인하였다. 특히 ANG35의 경우에는 7가지 식물병원성 곰팡이 중 6가지에 대해 비교적 높은 억제율을 나타내어 식물 생장 촉진뿐만 아니라 방제활성을 가지므로 식물이 생장하는 데 도움을 줄 것으로 기대된다. 또한, 4균주 간의 세포외 효소활성 synergy effect를 확인한 결과 단독배양을 했을 때보다 혼합배양 시 세포외 효소활성이 증가하는 것을 확인하였다. 따라서, 식물 생장촉진 활성 및 식물병원성 곰팡이에 대한 결과를 통해 새로운 생물학적 제제로서 이용 가능성을 제시한다.

• 한국토양비료학회지
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• 제20권3호
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• pp.269-274
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• 1987

간척지(干拓地) 토양(土壤)의 잡초(雜草) 및 수도근(水稻根) 조직(組織)에서 분리동정(分離同定)한 수종(數種)의 협생질소고정균(協生窒素固定菌)을 질소(窒素)를 함유(含有)하지 않은 순수배양(純粹培養) 내(內)에서 재배형(栽培型) 및 품종(品種)이 상이(相異)한 수도종자권(水稻種子圈)에 접종(接種)하여 수도(水稻)의 건물중(乾物重), 초장(草長), 근장(根長), 근수등(根數等)의 생육특징(生育特徵)과 협생질소고정력(協生窒素固定力)을 조사(調査)한 결과(結果) 수도품종(水稻品種) 및 협생질소고정균(協生窒素固定菌)의 조합간(組合間) 교호작용(交互作用)은 통계적(統計的)으로 유의(有意)한 상관관계(相關關係)를 보이지 않했다. 그러나 공시수도품종중(供試水稻品種中)에서 Annapuruna는 7종(種)의 협생질소고정균(協生窒素固定菌)을 접종(接種)하므로써 생육량(生育量) 증가(增加)를 보였다. 그리고 7종(種)의 협생질소고정균(協生窒素固定菌)을 교호접종(交互接種)했을때 협생질소고정력(協生窒素固定力)은 Annapuruna와 신광(新光)벼 조합(組合)에서 가장 높았으며 IR-8이 가장 낮았다. 또한 협생질소고정균(協生窒素固定菌)과 수도품종간(水稻品種間)에는 신광(新光)벼와 Pseudomonas sp. H8 조합(組合)에서 질소고정력(窒素固定力)이 가장 높았다.

• 한국토양비료학회지
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• 제44권1호
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• pp.58-66
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• 2011

Arsenic pollution is a serious global concern which affects all life forms. Being a toxic metalloid, the continued search for appropriate technologies for its remediation is needed. Phytoremediation, the use of green plants, is not only a low cost but also an environmentally friendly approach for metal uptake and stabilization. However, its application is limited by slow plant growth which is further aggravated by the phytotoxic effect of the pollutant. Attempts to address these constraints were done by exploiting plant-microbe interactions which offers more advantages for phytoremediation. Several bacterial mechanisms that can increase the efficiency of phytoremediation of As are nitrogen fixation, phosphate solubilization, siderophore production, ACC deaminase activity and growth regulator production. Many have been reported for other metals, but few for arsenic. This mini-review attempts to present what has been done so far in exploring plants and their rhizosphere microbiota and some genetic manipulations to increase the efficiency of arsenic soil phytoremediation.

• 농업과학연구
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• 제50권4호
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• pp.759-771
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• 2023

Plant growth-promoting rhizobacteria (PGPR) are naturally occurring bacteria that intensively colonize plant roots and are crucial in promoting the crop growth. These beneficial microorganisms have garnered considerable attention as potential bio-inoculants for sustainable agriculture. PGPR directly interacts with plants by providing essential nutrients through nitrogen fixation and phosphate solubilization and accelerating the accessibility of other trace elements such as Cu, Zn, and Fe. Additionally, they produce plant growth-promoting phytohormones, such as indole acetic acids (IAA), indole butyric acids (IBA), gibberellins, and cytokinins.PGPR interacts with plants indirectly by protecting them from diseases and infections by producing antibiotics, siderophores, hydrogen cyanide, and fungal cell wall-degrading enzymes such as glucanases, chitinases, and proteases. Furthermore, PGPR protects plants against abiotic stresses such as drought and salinity by producing 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase and modulating plant stress markers. Bacteria belonging to genera such as Bacillus, Pseudomonas, Burkholderia, Pantoa, and Enterobacter exhibit multiple plant growth-promoting traits, that can enhance plant growth directly, indirectly, or through synergetic effects. This comprehensive review emphasizes how PGPR influences plant growth promotion and presents promising prospects for its application in sustainable agriculture.

• Journal of Applied Biological Chemistry
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• 제42권1호
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• pp.1-6
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• 1999

Poly-${\beta}$-hydroxybutyrate (PHB) and enzymes related PHB metabolism have been measured in nitrogen-fixing symbiosis of chickpea and cowpea plants. Bacteroids from chickpea and cowpea contained PHB to 0.8% and 43% of their dry weight, respectively, whereas the free-living cells CC 1192 and I 16 produced $285{\pm}55mg$ and $157{\pm}18mg$ of PHB g (dry weight)$^{-1}$. To further understand why chickpea bacteroids contained little PHB, the enzyme activities of PHB metabolism (3-ketothiolase, acetoacetyl-CoA reductase, PHB depolymerase, and 3-hydroxybutyrate dehydrogenase), the TCA cycle (malate dehydrogenase, citrate synthase, and isocitrate dehydrogenase), and related reactions (malic enzyme, pyruvate dehydrogenase, and glutamate:2-oxoglutarate transaminase) were compared in extracts from chickpea and cowpea bacteroids and the respective free-living bacteria. Significant differences were observed between chickpea and cowpea bacteroids and between the bacteroid and free-living forms of CC 1192, with respect to the capacity for some of these reactions. It is indicated that a greater potential for oxidizing malate to oxaloacetate in chickpea bacteroids could be a factor that favors the utilization of acetyl-CoA in TCA cycle rather than for PHB synthesis.

• 미생물학회지
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• 제49권2호
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• pp.131-136
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• 2013

본 연구에서는 헤어리베치로부터 뿌리혹 형성능과 질소 고정능이 우수한 Rhizobium 균주를 분리하고자 하였다. 전국의 일곱 군데 헤어리베치 재배 지역에서 수집 후 뿌리혹으로부터 균주를 분리하였고, 헤어리베치에 분리 균주를 재접종하여 뿌리혹 형성능과 질소 고정능을 확인하였다. 그 결과, 52개의 Rhizobium 속 균주를 분리하였고, 이 중 0.5% NaCl 농도 이상에서 자라는 Rhizobium은 16균주이었다. 뿌리혹 형성능은 16개 균주 중 Rhizobium sp. RH1, RH3, RH81, RH82, RH84, RH93의 균주를 접종한 시험구에서 우수하였다. 또한, 질소 고정능을 확인한 결과 Rhizobium sp. RH84가 가장 높은 acetylene reduction activity를 보였다. 이러한 결과는 향후 염의 분포가 불균일한 간척지에 적용 시에도 헤어리베치의 생육을 촉진해 녹비 작물로의 활용 가능성을 높여주는 결과로 판단된다.

• Journal of Microbiology and Biotechnology
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• 제20권11호
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• pp.1577-1584
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• 2010

In total, 140 halotolerant bacterial strains were isolated from both the soil of barren fields and the rhizosphere of six naturally growing halophytic plants in the vicinity of the Yellow Sea, near the city of Incheon in the Republic of Korea. All of these strains were characterized for multiple plant growth promoting traits, such as the production of indole acetic acid (IAA), nitrogen fixation, phosphorus (P) and zinc (Zn) solubilization, thiosulfate ($S_2O_3$) oxidation, the production of ammonia ($NH_3$), and the production of extracellular hydrolytic enzymes such as protease, chitinase, pectinase, cellulase, and lipase under in vitro conditions. From the original 140 strains tested, on the basis of the latter tests for plant growth promotional activity, 36 were selected for further examination. These 36 halotolerant bacterial strains were then tested for 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity. Twenty-five of these were found to be positive, and to be exhibiting significantly varying levels of activity. 16S rRNA gene sequencing analyses of the 36 halotolerant strains showed that they belong to 10 different bacterial genera: Bacillus, Brevibacterium, Planococcus, Zhihengliuella, Halomonas, Exiguobacterium, Oceanimonas, Corynebacterium, Arthrobacter, and Micrococcus. Inoculation of the 14 halotolerant bacterial strains to ameliorate salt stress (150 mM NaCl) in canola plants produced an increase in root length of between 5.2% and 47.8%, and dry weight of between 16.2% and 43%, in comparison with the uninoculated positive controls. In particular, three of the bacteria, Brevibacterium epidermidis RS15, Micrococcus yunnanensis RS222, and Bacillus aryabhattai RS341, all showed more than 40% increase in root elongation and dry weight when compared with uninoculated salt-stressed canola seedlings. These results indicate that certain halotolerant bacteria, isolated from coastal soils, have a real potential to enhance plant growth under saline stress, through the reduction of ethylene production via ACC deaminase activity.

• 한국미생물·생명공학회지
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• 제49권3호
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• pp.391-402
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• 2021

Earthworms play an important role in soil fertilization, interacting continually with microorganisms. This study aims to demonstrate the existence of beneficial microorganisms living in the earthworm's immune system, the coelomic fluid. To achieve this goal, a molecular identification technique was performed, using cytochrome c oxidase I (COI) barcoding to identify abundant endogenic earthworms inhabiting the temperate zone of Rabat, Morocco. Then, 16S rDNA and ITS sequencing techniques were adopted for bacteria and fungi, respectively. Biochemical analysis, showed the ability of bacteria to produce characteristic enzymes and utilize substrates. Qualitative screening of plant growth-promoting traits, including nitrogen fixation, phosphate and potassium solubilization, and indole acetic acid (IAA) production, was also performed. The result of mitochondrial COI barcoding allowed the identification of the earthworm species Aporrectodea molleri. Phenotypic and genotypic studies of the sixteen isolated bacteria and the two isolated fungi showed that they belong to the Pseudomonas, Aeromonas, Bacillus, Buttiauxella, Enterobacter, Pantoea, and Raoultella, and the Penicillium genera, respectively. Most of the isolated bacteria in the coelomic fluid showed the ability to produce β-glucosidase, β-glucosaminidase, Glutamyl-β-naphthylamidase, and aminopeptidase enzymes, utilizing substrates like aliphatic thiol, sorbitol, and fatty acid ester. Furthermore, three bacteria were able to fix nitrogen, solubilize phosphate and potassium, and produce IAA. This initial study demonstrated that despite the immune property of earthworms' coelomic fluid, it harbors beneficial microorganisms. Thus, the presence of resistant microorganisms in the earthworm's immune system highlights a possible selection process at the coelomic fluid level.