• Journal of Microbiology and Biotechnology
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• 제19권11호
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• pp.1431-1438
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• 2009

The role of plant growth-promoting rhizobacteria (PGPR) in the phytoremediation of heavy-metal-contaminated soils is important in overcoming its limitations for field application. A plant growth-promoting rhizobacterium, Serratia sp. SY5, was isolated from the rhizoplane of barnyard grass (Echinochloa crus-galli) grown in petroleum and heavy-metal-contaminated soil. This isolate has shown capacities for indole acetic acid production and siderophores synthesis. Compared with a non-inoculated control, the radicular root growth of Zea mays seedlings inoculated with SY5 can be increased by 27- or 15.4-fold in the presence of 15 mg-Cd/l or 15 mg-Cu/l, respectively. The results from hydroponic cultures showed that inoculation of Serratia sp. SY5 had a favorable influence on the initial shoot growth and biomass of Zea mays under noncontaminated conditions. However, under Cd-contaminated conditions, the inoculation of SY5 significantly increased the root biomass of Zea mays. These results indicate that Serratia sp. SY5 can serve as a promising microbial inoculant for increased plant growth in heavy-metal-contaminated soils to improve the phytoremediation efficiency.

• Plant Biotechnology Reports
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• 제4권3호
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• pp.179-183
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• 2010

Ethylene is a key gaseous hormone that controls various physiological processes in plants including growth, senescence, fruit ripening, and responses to abiotic and biotic stresses. In spite of some of these positive effects, the gas usually inhibits plant growth. While chemical fertilizers help plants grow better by providing soil-limited nutrients such as nitrogen and phosphate, overusage often results in growth inhibition by soil contamination and subsequent stress responses in plants. Therefore, controlling ethylene production in plants becomes one of the attractive challenges to increase crop yields. Some soil bacteria among plant growth-promoting rhizobacteria (PGPRs) can stimulate plant growth even under stressful conditions by reducing ethylene levels in plants, hence the term "stress controllers" for these bacteria. Thus, manipulation of relevant genes or gene products might not only help clear polluted soil of contaminants but contribute to elevating the crop productivity. In this article, the beneficial soil bacteria and the mechanisms of reduced ethylene production in plants by stress controllers are discussed.

• 한국토양비료학회지
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• 제49권6호
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• pp.776-782
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• 2016

Salinity has been a threat to agriculture in some parts of the world; and recently, the threat has grown. Plant growth-promoting rhizobacteria (PGPR) may benefit plant growth, either by improving plant nutrition or producing plant growth hormones. The effects of rhizobacterial strains to attenuate the salinity stress on the germination of Chinese cabbage seeds were tested using four different concentrations of NaCl (50, 100, 150, and 200 mM). Also, PGPR strains were tested to enhance the early germination of Chinese cabbage seeds under normal conditions. Azotobacter chroococcum performed best with enhancing the radicle length of 4.0, 1.2, and 1.0 times at treatments of 50, 100, and 150 mM of NaCl, respectively. Additionally, significant differences were found in plumule length, A. chroococcum and Lactobacillus sp. showed remarkable activation either in normal or under stress conditions. Co-inoculation by three rhizobacterial strains (LAPmix) indicated synergistic effect to enhance the early germination of the seeds. The results of this study are promising for application of rhizobacterial strains that possess plant growth promoting traits to enhance the plant tolerance against salinity.

• KSBB Journal
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• 제31권1호
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• pp.58-65
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• 2016

In this study, Arthrobacter scleromae SYE-3, which was isolated from indigenous plant in a subtropical region, Neigeria, with plant growth promoting activity was evaluated to determine the optimal culture condition. A bacterial strain SYE-3 had the IAA productivity ($89.15{\pm}0.36mg/L$) and ACC deaminase activity ($0.20{\pm}0.06$ at 72 hours). Also, optimal culture conditions such as temperature and pH of strain SYE-3 were $20^{\circ}C$ and 10 in LB medium, respectively. Strain SYE-3 had up to 3% salt tolerance in the LB medium. Plant growth promoting ability of strain SYE-3 using yam (Dioscorea japonica Thunb.) was evaluated. As a result, strain SYE-3 had showed very powerful effect on the increase of the shoot length and root biomass of yam (190.0% and 282.41% increase for 112 days, respectively). These results indicated that Arthrobacter scleromae SYE-3 can serve as a promising microbial resource for the biofertilizers of subtropical crops.

• 한국균학회지
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• 제49권4호
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• pp.441-454
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• 2021

Fungal diseases including anthracnose, stem rot, blight, wilting, and root rot of crops are caused by phytopathogens such as Colletotrichum species, Sclerotinia sclerotiorum, Phytophthora species, and Fusarium oxysporum and F. solani which threaten the production of chili pepper. In this study, to identify biological control agents (BCAs) of phytopathogenic fungi, potentially useful Bacillus species were isolated from the field soils. We screened out five Bacillus strains with antagonistic capacity that are efficiently inhibiting the growth of phytopathogenic fungi. Bacillus species were characterized by the production of extracellular enzymes, siderophores, and indole-3-acetic acid (IAA). Furthermore, the influence of bacterial strains on the plant growth promoting activity and seedling vigor index were assessed using Brassica juncea as a model plant. Inoculation with Bacillus subtilis SRCM 121379 significantly increased the length of B. juncea shoots and roots by 45.6% and 52.0%, respectively. Among the bacterial isolates, Bacillus subtilis SRCM 121379 showed the superior enzyme activities, antagonistic capacity and plant growth promoting effects. Based on the experimental results, Bacillus subtilis SRCM 121379 (GenBank accession no. NR027552) was finally selected as a BCA candidate.

• 한국미생물·생명공학회지
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• 제48권4호
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• pp.399-422
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• 2020

도시화 및 산업화로 인해 발생된 중금속으로 오염된 토양의 정화는 인간의 건강 뿐 아니라 지구생태계의 지속성을 위해 매우 중요하다. 중금속 오염 토양 정화 기술 중 식물상복원법은 타 방법에 비해 처리 단가가 저렴하고, 토양 비옥도 및 생물 다양성이 영향을 덜 받는 환경친화적인 방법이다. 이러한 식물상복원법에 식물생장촉진세균(plant growth promoting bacteria, PGPB)을 도입하여 중금속 독성 하에서 식물 생장을 촉진하고 중금속 정화 효율을 향상시킬 수 있다. 본 논문에서는 주요 토양오염물인 중금속의 발생원, 미생물·식물·인간에 미치는 중금속 영향 및 PGPB의 식물생장촉진 기작을 정리하였다. 중금속 오염 토양 정화를 위하여 식물상복원에 PGPB의 활용에 관한 최근 10년 동안의 연구 동향을 분석하였다. 또한, PGPB의 실제 적용 시 중금속 제거 효율에 미치는 다양한 환경 인자와 PGPB의 접종 방법의 영향을 고찰하였다. PGPB 활용 식물상복원 기술의 혁신을 위해서는 실제 현장에서 PGPB의 거동과 식물-PGPB-자생미생물 사이의 상호작용에 대한 이해가 필요하다.

• 한국토양비료학회지
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• 제43권4호
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• pp.514-521
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• 2010

지속가능한 친환경농업을 위해서는 비료와 함께 식물생장촉진 미생물 또는 생장조절물질을 적절히 혼합 사용하는 것이 바람직하다. 본 연구에서는 Methylobacterium oryzae CBMB20의 근권토양접종과 메탄올 엽면살포에 따른 고추의 생육촉진 효과를 유기질 비료의 시용 수준별로 조사하였다. M. oryzae CBMB20의 근권토양접종과 메탄올 엽면살포는 각기 고추생육을 증대시켰다. 또한 이들을 동시에 혼합 처리하였을 경우에는 고추의 생장촉진 효과가 더욱 현저하게 나타났다. M. oryzae CBMB20의 근권토양접종과 메탄올 엽면살포에 따른 고추 생장촉진 효과는 유기질 비료의 시용수준이 낮은 경우에 더욱 현저하게 나타났다. M. oryzae CBMB20와 메탄올을 혼합 처리한 경우 권장시비수준 100%와 300% 처리 사이에 고추생육과 수량에서 유의성 있는 차이가 없었다. 시비량이 지나치게 많을 경우 생장촉진제의 처리효과를 거둘 수 없으며, 적정한 시비 수준에서 M. oryzae CBMB20와 메탄올을 혼합 처리함으로써 고추를 비롯한 작물의 생장과 수량을 유지하면서도 시비량을 크게 줄일 수 있을 것으로 판단된다.

• The Plant Pathology Journal
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• 제29권2호
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• pp.174-181
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• 2013

The plant growth-promoting rhizobacterium Ochrobactrum lupini KUDC1013 elicited induced systemic resistance (ISR) in tobacco against soft rot disease caused by Pectobacterium carotovorum subsp. carotovorum. We investigated of its factors involved in ISR elicitation. To characterize the ISR determinants, KUDC1013 cell suspension, heat-treated cells, supernatant from a culture medium, crude bacterial lipopolysaccharide (LPS) and flagella were tested for their ISR activities. Both LPS and flagella from KUDC1013 were effective in ISR elicitation. Crude cell free supernatant elicited ISR and factors with the highest ISR activity were retained in the n-butanol fraction. Analysis of the ISR-active fraction revealed the metabolites, phenylacetic acid (PAA), 1-hexadecene and linoleic acid (LA), as elicitors of ISR. Treatment of tobacco with these compounds significantly decreased the soft rot disease symptoms. This is the first report on the ISR determinants by plant growth-promoting rhizobacteria (PGPR) KUDC1013 and identifying PAA, 1-hexadecene and LA as ISR-related compounds. This study shows that KUDC1013 has a great potential as biological control agent because of its multiple factors involved in induction of systemic resistance against phytopathogens.

• The Plant Pathology Journal
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• 제31권3호
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• pp.310-315
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• 2015

Certain bacterial species associate with plant roots in soil. The plant growth-promoting rhizobacteria (PGPR) stimulate plant growth and yield in greenhouse and field. Here, we examined whether application of known bacilli PGPR strains stimulated growth and asexual reproduction in the succulent plant Kalanchoe daigremontiana. Four PGPR strains B. amyloliquefaciens IN937a, B. cereus BS107, B. pumilus INR7, and B. subtilis GB03 were applied to young plantlets by soil-drenching, and plant growth and development was monitored for three months. Aerial growth was significantly stimulated in PGPR-inoculated plants, which was observed as increases in plant height, shoot weight, and stem width. The stimulated growth influenced plant development by increasing the total number of leaves per plant. Treatment with bacilli also increased the total root biomass compared with that of control plants, and led to a 2-fold increase in asexual reproduction and plantlet formation on the leaf. Collectively, our results firstly demonstrate that Bacillus spp. promote vegetative development of K. daigremontiana, and the enhanced growth stimulates asexual reproduction and plantlet formation.

• Journal of Applied Biological Chemistry
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• 제43권2호
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• pp.104-108
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• 2000

The plant growth-promoting activity of Acremonium strictum MJN1 isolated from roots of Panox ginseng was explored. The myceliaI extract of A. strictum MJN1 enhanced the rice seedling growth by 14.5 and 9.0% in the dried weight of shoots and roots, and the growth of red pepper by 54 and 85% in the top length and the dried weight in pot experiments, respectively. The plant growth-promoting substances in the myceliaI extract of Acremonium strictum MJN1 were identified as D-adenosine and glycerol. Both commercial D-adenosine and glycerol also promoted significantly the rice seedling growth but, unlike the mycelial extract of A. strictum MJN1, hardly affected the yields of plants grown in pots or field. Therefore, it is possible that other plant growth-promoting substances are produced by A. strictum MJN1. However, this study shows that A. strictum MJN1 has a great potential as a biofertilizer.