• The Plant Pathology Journal
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• 제18권2호
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• pp.57-62
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• 2002

In vivo expression technology (IVET) has been developed to study bacterial gene expression in Salmonella typhimurium during host infection. The expression of selected genes by IVET has been elevated in vivo but not in vitro. The selected genes turned out to be important for bacterial virulence and/or pathogenicity. IVET depends on a synthetic operon with a promoterless transcriptional fusion between a selection marker gene and a reporter gene. The IVET approach has been successfully adapted in other bacterial pathogens and plant-associated bacteria using different selection markers. Pseudomonas putida suppresses citrus root rot caused by Phytophthora parasitica and enhances citrus seedling growth. The WET strategy was adapted based on a transcriptional fusion, pyrBC'-lacZ, in P. putida to study the bacterial traits important far biocontrol activities. Several genes appeared to be induced on P. parasitica hyphae and were found to be related with metabolism and regulation of gene expression. It is likely that the biocontrol strain took a metabolic advantage from the plant pathogenic fungus and then suppressed citrus root rot effectively. The result was parallel with those from the adaptation of IVET in P. fluorescens, a plant growth promoting rhizobacteria (PGPR). Interestingly, genes encoding components for type III secretion system have been identified as rhizosphere-induced genes in the PGPR strain. The type III secretion system may play a certain role during interaction with its counterpart plants. Application of IVET has been demonstrated in a wide range of bacteria. It is an important strategy to genetically understand complicated bacterial traits in the environment.

• Applied Biological Chemistry
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• 제40권2호
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• pp.167-171
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• 1997

26종 콩과식물 종실의 메탄올 조추출물의 Bifidobacterium adolescentis, B. longun, B. bifidum, Lactobacillus casei에 대한 생육촉진 및 생육억제 활성을 탄소원 배지와 비탄소원 배지를 이용하여 in vitro 혐기조건하에서 각각 분광학적 및 여지확산법으로 검정한 결과 생육반응은 공시세균과 콩의 종류에 따라 달리 나타났다. 콩과식물 종실중, 대두(밝은 청색 종실)와 땅콩 (짙은 갈색 종실) 추출물은 유산균의 생육을 촉진하였는데, 이러한 결과로 부터 이들 콩과식물 종실에 탄소원과 비탄소원의 비피더스 인자의 존재를 알 수 있었다. 공시 유산균 중에서 L. casei에서 가장 현저한 생육측진 반응을 나타내었다. 또한, 모든 콩과식물 종실시료는 상기 유산균의 생육을 저해하지 않았다.

• 한국토양비료학회지
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• 제30권2호
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• pp.196-199
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• 1997

식물생장촉진 효과가 있는 Micrococcus sp., Bacillus subtilis, Enterobacter agglomerans, Bacillus megaterium, Pseudomonas putide, Pseudomans fluorescens, Cellulomonas sp., Staphylococcus xylosus등 8종의 혼합균주 배양액을 오이에 처리하였을때 작물에 미치는 영향을 조사한 결과는 다음과 같다. 1. 균처리구는 대조구에 비해 수량은 18% 증수되었으며, 주당 수확과수는 평균 5.1개 정도 많았다. 2. 만장, 엽장, 엽폭은 균처리구와 대조구간에 차이가 없었지만 줄기의 굵기, 2차측지 발생율, 유인 측지절수, 절성성은 균처리구가 대조구에 비해 양호하였다. 3. 토양의 물리성중 가밀도, 공극률은 차이가 없었으나 수분율은 균처리구가 대조구에 비해 높은 경향이었으며, 토양 화학성은 균처리구가 대조구에 비해 EC, 유기물, Ca, $NO_3-N$ 함량은 낮아졌으며, 그외 성분은 높은 경향이었다.

• Journal of Microbiology and Biotechnology
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• 제29권7호
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• pp.1096-1103
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• 2019

UCB-1 is the commercial rootstock of pistachio. Reproduction of this rootstock by tissue culture is limited by low levels of proliferation rate. Therefore, any compound that improves the proliferation rate and the quality of the shoots can be used in the process of commercial reproduction of this rootstock. Use of plant growth-promoting bacteria is one of the best ideas. Given the beneficial effects of nanoparticles in enhancement of the growth in plant tissue cultures, the aim of the present study was to investigate the effects of nanoencapsulation of plant growth-promoting rhizobacteria (using silica nanoparticles and carbon nanotubes) and their metabolites in improving UCB1 pistachio micropropagation. The experiment was conducted in a completely randomized design with three replications. Before planting, treatments on the DKW medium were added. The results showed that the use of Pseudomonas fluorescens VUPF5 and Bacillus subtilis VRU1 nanocapsules significantly enhanced the root length and proliferation. The nanoformulation of the VUPF5 metabolite led to the highest root length (6.26 cm) and the largest shoot (3.34 cm). Inoculation of explants with the formulation of the metabolites (both bacterial strains) significantly elevated the average shoot length and the fresh weight of plant compared to the control. The explants were dried completely using both bacterial strains directly and with capsule coating after the three days.

• The Plant Pathology Journal
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• 제35권2호
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• pp.137-148
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• 2019

In search of an effective biological control agent against the tomato pathogen Fusarium oxysporum f. sp. lycopersici, rhizospheric soil samples were collected from eight agro-ecological zones of Bangladesh. Among the bacteria isolated from soil, 24 isolates were randomly selected and evaluated for their antagonistic activity against F. oxysporum f. sp. lycopersici. The two promising antagonistic isolates were identified as Brevundimonas olei and Bacillus methylotrophicus based on morphological, biochemical and molecular characteristics. These two isolates were evaluated for their biocontrol activity and growth promotion of two tomato cultivars (cv. Pusa Rubi and Ratan) for two consecutive years. Treatment of Pusa Rubi and Ratan seeds with B. olei prior to inoculation of pathogen caused 44.99% and 41.91% disease inhibition respectively compared to the untreated but pathogen-inoculated control plants. However, treatment of Pusa Rubi and Ratan seeds with B. methylotrophicus caused 24.99% and 39.20% disease inhibition respectively. Furthermore, both the isolates enhanced the growth of tomato plants. The study revealed that these indigenous bacterial isolates can be used as an effective biocontrol agent against Fusarium wilt of tomato.

• The Plant Pathology Journal
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• 제37권3호
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• pp.307-314
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• 2021

Pepper (Capsicum annuum L.) is an important agricultural crop worldwide. Recently, Colletotrichum scovillei, a member of the C. acutatum species complex, was reported to be the dominant pathogen causing pepper anthracnose disease in South Korea. In the present study, we isolated bacterial strains from rhizosphere soil in a pepper field in Gangwon Province, Korea, and assessed their antifungal ability against C. scovillei strain KC05. Among these strains, a strain named BS1 significantly inhibited mycelial growth, appressorium formation, and disease development of C. scovillei. By combined sequence analysis using 16S rRNA and partial gyrA sequences, strain BS1 was identified as Bacillus velezensis, a member of the B. subtilis species complex. BS1 produced hydrolytic enzymes (cellulase and protease) and iron-chelating siderophores. It also promoted chili pepper (cv. Nockwang) seedling growth compared with untreated plants. The study concluded that B. velezensis BS1 has good potential as a biocontrol agent of anthracnose disease in chili pepper caused by C. scovillei.

• 농업과학연구
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• 제43권1호
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• pp.100-108
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• 2016

An auxin-producing bacteria (strain 5-1) was isolated from button mushroom compost in Boryeong-Si, Chungcheongnam-Do. The 5-1 strain was classified as a novel strain of Enterobacter aerogenes based on chemotaxonomic and phylogenetic analyses. The isolated E. aerogenes 5-1 was confirmed to produce indole-3-acetic acid (IAA), one of the auxin hormones, using TLC and HPLC analyses. When the concentration of IAA was assessed by performing HPLC quantitative analysis, a maximum concentration of IAA of $109.9mgL^{-1}$ was detected in the culture broth incubated in R2A medium containing 0.1% L-tryptophan for 24 h at $35^{\circ}C$. Acidification of the culture was deemed caused by an increase of IAA because a negative relationship between IAA production and pH was observed. Supplementation with a known precursor of IAA production, L-tryptophan, appeared to induce maximal production at 0.1% concentration, but it reduced production at concentrations above 0.2%. To investigate the growth-promoting effects to crops, the culture broth of E. aerogenes 5-1 was used to inoculate water cultures and seed pots of mung bean and lettuce. In consequence, adventitious root induction and root growth of mung bean and lettuce were two times higher than those of the control.

• KSBB Journal
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• 제30권3호
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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).

• The Plant Pathology Journal
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• 제21권1호
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• pp.7-12
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• 2005

Plant growth-promoting rhizobacteria (PGPR) are a wide range of root-colonizing bacteria with the capacity to enhance plant growth and control plant pathogens. Here we review recent progress that indicate some PGPR strains release a blend of volatile organic compounds (VOCs) that promote growth in Arabidopsis seedlings and induce resistance against Erwinia carotovora subsp. carotovora. In particular, the volatile components 2,3-butanediol and acetoin released exclusively from the PGPR strains triggered the greatest level of growth promotion and induced systemic resistance. Pharmacological applications of 2,3-butanediol promoted the plant growth and induced resistance, while bacterial mutants blocked in 2,3-butanediol and acetoin synthesis was devoid of growth-promotion and induced resistance capacities. The results suggested that the bacterial VOCs play a critical role in the plant growth promotion and induced resistance by PGPR. Using transgenic and mutant lines of Arabidopsis, we provide evidences that the signal pathway activated by volatiles from one PGPR strain is dependent on cyto-kinin activation for growth promotion and dependent on an ethylene-signaling pathway for induced pathogen resistance. This discovery provides new insight into the role of bacterial VOCs as initiators of both plant growth promotion and defense responses in plants.

• 한국토양비료학회지
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• 제29권4호
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• pp.396-402
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• 1996

식물생육촉진 유용미생물을 지리산 일대의 침엽수와 활엽수 밑의 부엽토(腐葉土)에서 선발하고, 고추에 접종하였을때 고추 묘소질과 생육 및 수량에 미치는 영향에 대한 결과를 요약하면 다음과 같다. 1. 혼합배양결과 Pseudomonas P배지는 $25^{\circ}C$에 Micrococcus sp., Enterobacter agglomerans, Pseudomonas putida, Pseudomonas fluorescens등 4균주, Sabouraud dextrose배지에서는 $35^{\circ}C$에서 Bacillus subtilis, Cellulomonas sp., Bacillus megaterium, Staphylococcus xylosus등 4균주의 생육이 양호하였다. 2. 혼합균주 처리구는 무처리구에 비해 초장, 분지수등은 증가하였고, EC 수준이 높아질수록 초장은 작아진 반면, 분지수는 혼합균주 처리 58일(日) 이후 EC 2.9ds/m에 비해 EC 8.6 dS/m에서 많아지는 경향이었다. 수량은 혼합균주 처리구가 무처리구에 비해 13% 증수되었고, EC 수준이 높아질수록 감소하는 경향이었다. 3. 시험후 토양의 EC, $P_2O_5$, K, Ca, Mg, $NO_3-N$은 EC 수준이 높아질수록 현저하게 증가하는 경향이었으며, 혼합균주 처리구는 무처리구에 비해 OM 및 $NH_4{^+}-N$은 낮은 반면, EC, $P_2O_5$, K, Ca, Mg, $NO_3-N$은 높은 경향이었다. 4. 시험후 혼합균주 처리구는 무처리구에 비해 수분율이 높은 경향이었으며, EC 수준이 높아 질수록 가밀도 수분율, 공극율 등은 증가하는 경향이었다. 5. 혼합균주 처리구는 무처리구에 비해 과실과 엽에서 T-N, $P_2O_5$, $K_2O$, CaO, MgO함량이 높았으며, EC 수준이 높아질수록 $P_2O_5$, $K_2O$, MgO 함량은 증가한 반면, CaO 함량은 낮아지는 경향이었다.