• Journal of Microbiology and Biotechnology
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• 제17권11호
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• pp.1805-1810
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• 2007

Purple nonsulfur bacteria were isolated from river sediments and their growth promoting capabilities on tomato were examined. Isolated strains KL9 and BL6 were identified as Rhodopseudomonas spp. by 16S rDNA sequence analysis. Rhodopseudomonas strain KL9 maximally produced 5.56 mM/min/mg protein and $67.2\;{\mu}M/min/mg$ protein of indole-3-acetic acid (IAA) and 5-aminolevulinic acid (ALA), respectively, which may be one of the mechanisms of plant growth enhancement. The germination percentage of tomato seed, total length, and dry mass of germinated tomato seedling increased by 30.2%, 71.1%, and 270.8%, respectively, compared with those of the uninoculated control 7 days after inoculation of strain KL9. The lengths of the root and shoot of germinated seedling treated with 3 mM tryptophan, a precursor of IAA, increased by 104.4% and 156.5%, respectively, 7 days after inoculation of strain KL9. Rhodopseudomonas KL9 increased 123.5% and 54% of the root and shoot lengths of germinated seedling, respectively, treated with 15 mM glycine and succinate, precursors of ALA. This plant growth promoting capability of purple nonsulfur bacteria may be a candidate for a biofertilizer in agriculture.

• 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.

• International Journal of Industrial Entomology and Biomaterials
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• 제6권2호
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• pp.133-138
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• 2003

Five seed kernel namely, Neem (Azadirachta indica A. Juss.), Pongamia (Pongamia glabra L. Pierre), Tamarind (Tamarindus indica L.), Mahua (Madhuca indica Gmel.) and Shikakai (Acacia cancinna De.) were tested against hatching of eggs and larval mortality of Meloidogyne incognita causing root knot disease in mulberry along with Furadan (Carbofuran) and Bionema (a bioformulation developed from Verticillium chlamydosporium) for comparison. Results revealed that highest hush-up of hatching was observed in Neem (77.40%) and Pongamia (75.99%) seed kernel extracts at 100% concentration over the check. Similarly, highest larval mortality was observed in Neem and Pongamia by 76.00% and 74.50%, respectively at 100% concentration after 72 hrs of exposure period. Pot culture studies revealed that pre-application of seed kernel powders (20 days before inoculation of nematode) found to be more effective in controlling the root knot disease than post application. In pre application of seed kernel powders, maximum reduction of root knots was observed in case of Neem seed kernel powder (54.85%) followed by Pongamia (51.9%). Similar trend was also observed in reduction of egg masses/plant and nematode population ／250 cc soil. Rest of the seed kernel extracts was found to be less effective in suppression of hatching, enhancing the larval mortality and controlling the root knot disease. However, application of Furadan and Bionema tested for the comparison were found to be more effective than seed kernel powders. The generated information seems to be useful in developing an ecofriendly integrated approach for the control of root knot nematode disease in mulberry.

• The Plant Pathology Journal
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• 제15권2호
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• pp.127-130
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• 1999

Cytological changes of cowpea root at the early stage of root nodule formation (within 5 days after inoculation) were viewed by light and electron microscopy. The root region affected by the rhizobial infection, which was composed of a redial array of cortical cells, had prominent cell divisions, mostly anticlinal in the inner cortical cells and in addition oblique and periclinal in the outer cells. An infected root hair cell (or root hair-producing epidermal cell) had numerous infection threads and degenerated cytoplasm. Module meristem was formed adjacent to the infected root hair cell, and characterized by dense cytoplasm, prominent nucleus, numerous small vacuoles, and increased plastids, containing infection threads as well. Bacterial cells were dividing inside the infection thread, the wall materials of which appeared to be dissolved ad accumulated in small vacuoles. inner cortical cells contiguous to the nodule meristem appeared to be actively dividing and dedifferentiating; however, they were not infected by the rhizobia. These structural characteristics are similar to those in the Bradyrhizobium-soybean association previously reported, and may reflect the similar cytological process in cowpea in the early nodule formation.

• Journal of Microbiology and Biotechnology
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• 제21권1호
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• pp.55-61
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• 2011

Forty yeast strains isolated from soils taken from different locations in Egypt were tested for their P-solubilizing activities on the basis of analyzing the clear zone around colonies growing on a tricalcium phosphate medium after incubation for 5 days at $25^{\circ}C$, denoted as the solubilization index (SI). Nine isolates that exhibited P-solubilization potential with an SI ranging from 1.19 to 2.76 were genetically characterized as five yeasts belonging to the genus Saccharomyces cerevisiae and four non-Saccharomyces, based on a PCR analysis of the ITS1-26S region amplied by SC1/SC2 species-specific primers. The highest P-solubilization efficiency was demonstrated by isolate PSY- 4, which was identified as Saccharomyces cerevisiae by a sequence analysis of the variable D1/D2 domain of the 26S rDNA. The effects of single and mixed inoculations with yeast PSY-4 and Bacillus polymyxa on the P-uptake and growth of corn were tested in a greenhouse experiment using different levels of a phosphorus chemical fertilizer (50, 100, and 200 kg/ha super phosphate 15.5% $P_2O_5$). The results showed that inoculating the corn with yeast PSY-4 or B. polymyxa caused significant increases in the shoot and root dry weights and P-uptake in the shoots and roots. The P-fertilization level also had a significant influence on the shoot and root dry weights and P-uptake in the shoots and roots when increasing the P-level from 50 up to 200 kg/ha. Dual inoculation with yeast strain PSY-4 and B. polymyxa at a P-fertilization level of 200 kg/ha gave higher values for the shoot and root dry weights and P-uptake in the shoots and roots, yet these increases were nonsignificant when compared with dual inoculation with yeast strain PSY-4 and B. polymyxa at a P-fertilization level of 100 kg/ha. The best increases were obtained from dual inoculation with yeast strain PSY-4 and B. polymyxa at a P-fertilization level of 100 kg/ha, which induced the following percentage increases in the shoot and root dry weights, and P-uptake in the shoots and roots; 16.22%, 46.92%, 10.09%, and 31.07%, respectively, when compared with the uninoculated control (fertilized with 100 kg/ha).

• 한국토양비료학회지
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• 제32권1호
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• pp.68-75
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• 1999

인산축적 시설재배지에서 Arbuscular mycorrhizal fungj의 이용을 위한 기초자료를 얻고자 비교적 내생균근균의 의존도가 높은 고추를 대상으로한 AMF의 전종방법 및 인간시용량에 따른 AMF의 접종효과를 검토하였다. 두 균주의 접종효율을 증진하기 위하여 접종시기, 접종밀도 및 배합토내 인산수준에 따른 고추의 생장반응을 본 결과, 배지내 인산수준별로는 $200mg\;P\;kg.soil^{-1}$이하의 수준에서 AMF접종시 유의적인 생체중 증가를 보였다. 인산시비량에 따른 고추의 AMF 감염율은 두 종 모두 인산수준이 낮을수록 높은 경향이었고 고추의 생체중은 무접종에 비하여 5~34%정도 높았다. 또한 AMF의 접종시 고추의 무기성분은 $P_2O_5$, $K_2O$의 함량이 뚜렷이 증가하였으며 특히 인산과 칼륨은 지상부에 비해 지하부에서의 증가가 더욱 뚜렷하였다. 이상의 결과로 보아 고추의 육묘시 AMF를 접종하면 지하부의 발달로 인한 고추이식시 근부손상의 감소와 이식직후 묘의 활착회복 및 균일성의 증가로 생육촉진효과가 증대될 것으로 기대되었다.

• 한국토양비료학회지
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• 제20권1호
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• pp.85-88
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• 1987

상수리나무에 대한 모래밭버섯균(Pt)와 알버섯균(Rr)의 접종효과(接種效果) 및 적정(適正) Pt 접종량(接種量)을 구명(究明)코저 토양소독(土壤消毒)을 실시(實施)하고 균근균(菌根菌)을 접종(接種)한 결과(結果)는 다음과 같다. 1. 균근형성율(菌根形成率)은 생장(生長) 2년차(年次)에 Pt가 최고(最高) 42%, Rr이 36%로 비교적 낮았으나 1년차(年次)에는 높았을 것으로 생각된다. 2. 상수리나무묘목(苗木)의 생장(生長)은 토양소독구(土壤消毒區)에서 우세하였으며 특히 Pt 배량접종구(倍量接種區)가 가장 좋았다. 3. Rr 접종구(接種區)는 Pt 접종구(接種區)와 비슷한 생장(生長)을 하여 Rr 균(菌)의 접종효과(接種效果)가 나타났다. 4. 토양소독후(土壤消毒後) 균접종(菌接種)으로 지하부(地下部) 중량(重量)이 크게 증가(增加)하였으며 따라서 조림후(造林後) 활착율증대(活着率增大)가 기대된다. 그러나 토양무소독구(土壤無消毒區)에서는 균접종효과(菌接種效果)가 뚜렷하지 않았음. 5. 엽내양분함량(葉內養分含量)은 N과 $P_2O_5$에서 처리간(處理間)의 차(差)없이 상당히 높았고 $K_2O$와 CaO는 토양소독접종구(土壤消毒接種區)가 높아 균접종(菌接種)에 의한 양분흡수(養分吸收) 효과(效果)가 인정(認定)되었다.

• 한국토양비료학회지
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• 제40권4호
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• pp.249-254
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• 2007

식물생장촉진 미생물을 농업적으로 활용하는데 있어서 미생물의 접종 수준이 근권에서의 원활한 정착과 식물의 생장촉진 효과를 결정하는데 중요한 기준이 된다. Azospirillum brasilense CW903균주 $10^5$, $10^6$ 및 $10^8cfu\;mL^{-1}$ 현택액에 토마토, 벼, 고추의 종자를 침지시킨 후 포트에 파종하여 온실에서 재배하였으며 파종 후 20일과 30일에 1 mL씩 근권토양에 접종하여 각 식물의 생장과 양분흡수를 조사하였다. Azospirillum brasilense CW903 균주 $10^6$ 및 $10^8cfu\;mL^{-1}$ 현택액을 처리하였을 때 식물생장 촉진효과가 나타났으며, $10^8cfu\;mL^{-1}$ 현택액을 처리하였을 각 식물의 줄기와 뿌리의 생장 및 양분흡수가 가장 우수한 것으로 나타났다.

• 한국산림과학회지
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• 제83권4호
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• pp.531-539
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• 1994

본 연구는 모래밭버섯 균근균(菌根菌)(Pisolithus tinctorius)의 인공접종(人工接種)이 30년생(年生) 상수리나무와 소나무 조직배양묘(組織培養苗)의 줄기생장과 발근(發根)에 미치는 영향(影響)을 조사(調査)하여, 조직배양(組織培養)을 통한 영양증식(營養增殖)에 균근균(菌根菌)의 잠재적(潛在的) 이용가능성(利用可能性)을 파악(把握)하고자 수행(遂行)하였다. 상수리나무의 아배양(芽培養)은 겨울철에 휴면상태(休眠狀態)에 있는 30년생(年生) 개체목(個體木)에서 채취(採取)한 휴면지(休眠枝)의 동아(冬芽)를 이용(利用)하여 실시(實施)하였고, 소나무의 기내삽목(器內揷木)은 종자(種子)에서 발아(發芽)한 실생묘(實生苗)를 이용(利用)하였다. 전반적(全般的)으로 상수리나무와 소나무 모두 모래밭버섯 균근균(菌根菌)의 접종(接種)으로 부정근(不定根)의 수(數), 길이, 발근율(發根率), 생존율(生存率) 등이 향상(向上)되었다. 소나무는 생존율(生存率)이 100%로 처리간(處理間)에 차이(差異)를 보이지 않았지만, 상수리나무에서는 접종구(接種區)가 100%인 반면(反面), 비접종구(非接種區)는 75%로 나타났다. 발근율(發根率)에 있어서도 소나무 기내삽목(器內揷木)에서는 발근율(發根率)이 비접종구(非接種區)에서 63%에 그친 반면(反面)에, 접종구(接種區)는 100%로 나타났고, 상수리나무는 비접종구(非接種區)가 20%로 매우 낮은 데 비(比)하여 접종구(接種區)가 70%로 유의적(有意的)인 균근균(菌根菌) 접종효과(接種效果)가 나타났다. 따라서 기내(器內) 삽목(揷木)과 조직배양(組織培養)에 균근균(菌根菌)을 응용(應用)함으로서, 발근유도(發根誘導)와 뿌리 발달(發達) 및 줄기 생장(生長)을 촉진(促進)시킬 수 있을 것으로 기대(期待)된다.

• 한국토양비료학회지
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• 제45권1호
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• pp.59-65
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• 2012

Plant growth-promoting effects of rhizobacterial inoculation obtained in pot experiments cannot always be dependably reproduced in fields. In this study, we investigated the effect of inoculation with Azospirillum brasilense and Methylobacterium oryzae, which have displayed growth promoting effects in several pot experiments, on growth and fruit yield of red pepper under field condition in a plastic-film house. Four rows spaced 90 cm apart were prepared after application of compost ($10Mg\;ha^{-1}$), and red pepper seedlings (Capsicum annum L., Nocgwang) were transplanted in each row with 40-cm space. Experimental treatments were consisted of A. brasilense CW903 inoculation, M. oryzae CBMB20 inoculation, and uninoculated control. Twelve plots, 10 plants per plot, were allotted to the three treatments with four replicates in a completely randomized design. At the time of transplanting, 50 mL of each inoculum ($1{\times}10^8cells\;mL^{-1}$) was introduced into root zone soil of each plant, and re-inoculated at 7 and 14 days after transplant. Plant growth and fruit yield were measured during the experiment. Both A. brasilense CW903 and M. oryzae CBMB20 could not promote growth of red pepper plants. All growth parameters measured were not significantly different among treatments. There were large variations in fruit yield recorded on plot basis, and no statistically significant differences were found among treatments. The failure to demonstrate the expected plant growth promoting effect of the inoculants is possibly due to various environmental factors, including weather and soil characteristics, reducing the possibility to express the potential of the inoculated bacterial strains.