• Journal of Microbiology and Biotechnology
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• 제19권10호
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• pp.1250-1258
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• 2009

Bacillus spp., as a type of plant growth-promoting rhizobacteria (PGPR), were studied with regards promoting plant growth and inducing plant systemic resistance. The results of greenhouse experiments with tobacco plants demonstrated that treatment with the Bacillus spp. significantly enhanced the plant height and fresh weight, while clearly lowering the disease severity rating of the tobacco mosaic virus (TMV) at 28 days post-inoculation (dpi). The TMV accumulation in the young non-inoculated leaves was remarkably lower for all the plants treated with the Bacillus spp. An RT-PCR analysis of the signaling regulatory genes Coil and NPR1, and defense genes PR-1a and PR-1b, in the tobacco treated with the Bacillus spp. revealed an association with enhancing the systemic resistance of tobacco to TMV. A further analysis of two expansin genes that regulate plant cell growth, NtEXP2 and NtEXP6, also verified a concomitant growth promotion in the roots and leaves of the tobacco responding to the Bacillus spp.

• 한국토양비료학회지
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• 제43권1호
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• pp.96-104
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• 2010

무균 및 온실조건에서 indole-3-acetic acid (IAA)의 처리와 1-aminocyclopropane-1-carboxylate deaminase (ACCD) 및 IAA 활성을 갖는 Methylobacterium 균주 접종 시 토마토와 고추의 생장을 비교 평가하였다. 무균조건에서 1.0 ${\mu}g\;mL^{-1}$의 IAA는 고추와 토마토의 뿌리생장을 촉진시키는데 비해 10.0 ${\mu}g\;mL^{-1}$ 이상의 높은 농도에서는 뿌리생장이 억제되었다. 그러나 높은 ACCD 활성을 갖고, IAA 활성은 낮거나 가지고 있지 않은 Methylobacterium 균주들을 접종하였을 때에는 고추와 토마토 모두 IAA 처리구 보다 뿌리생장이 증진되는 것을 확인하였다. 마찬가지로 온실조건에서 Methylobacterium 균주들을 접종했을 때, 마디길이와 잎의 크기 그리고 단위 면적당 잎의 무게 (SLW)에서 유의성 있는 증진효과를 보였다. 전반적인 식물 생장에서 저농도의 IAA 처리 효과는 Methylobacterium의 효과와 비슷한 경향을 나타냈다. 유묘의 지상부 길이는 ACCD 활성과 IAA 생산능을 갖는 Methylobacterium 균주 처리구에서 유의성 있는 증가를 확인할 수 있었으며, 전체 건물중 또한 Methylobacterium 처리 시 유의성 있는 증진 효과를 확인 할 수 있었다. 하지만 고농도의 IAA는 고추와 토마토의 생물량을 억제시켰다. 이러한 결과는 접종 균주의 IAA와 ACCD가 고추와 토마토 유묘의 생장 증진에 영향을 끼친다는 것을 증명한다.

• Journal of Plant Biology
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• 제20권2호
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• pp.103-107
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• 1977

Two sample varieties of Yushin and Jinheung were used for the experiment in low-level wetty paddy field which was arranged with PVC pipe underdrainage of 6m in distance and 60cm, 90cm, and 120cm in depth and control, using sprit plot design with three replications. On the yield of brown rice, Yushin was increased by 24.8% in the 90cm plot and Jinheung by 16.7% in the 120cm plot, respectively, over the control. The ratio of matured grains of these two varieties was increased significantly by the underdrainage and the number of grains per head of Yushin was also increased in drained plots. Otherwise, the underdrainage enhanced the plant height in the early growth of rice plant and further increased the culm height and panicle length. It seemed that these results might enhance the light-receiving effciency in the latter growth of rice plant and bring about the effect fo increased yields by the underdrainage.

• Journal of Plant Biotechnology
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• 제38권3호
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• pp.228-233
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• 2011

Nucleoside diphosphate kinase 2 (NDPK2) is known to regulate the expression of antioxidant genes and auxin-responsive genes in plants. Previously, it was noted that the overexpression of Arabidopsis NDPK2 (AtNDPK2) under the control of an oxidative stress-inducible SWPA2 promoter in transgenic poplar (Populus alba ${\times}$ P. tremular var. glandulosa) plants (referred to as SN plants) enhanced tolerance to oxidative stress and improved growth (Plant Biotechnol J 9: 34-347, 2011). In this study, growth of transgenic poplar was assessed under living modified organism (LMO) field conditions in terms of biomass in the next year. The growth of transgenic poplar plants increased in comparison with non-transgenic plants. The SN3 and SN4 transgenic lines had 1.6 and 1.2 times higher dry weight in stems than non-transgenic plants at 6 months after planting, respectively. Transgenic poplar also exhibited increased transcript levels of auxin-response genes such as IAA1, IAA2, IAA5 and IAA6. These results suggest that enhanced AtNDPK2 expression increases plant biomass in transgenic poplar through the regulation of auxin-response genes.

• Journal of Crop Science and Biotechnology
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• 제10권1호
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• pp.45-49
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• 2007

Silicon is one of the key elements for healthy growth and development in rice crops. We analyzed the effect of silicon(Si) on some growth parameters, plant mineral contents, and bioactive gibberellins in three rice cultivars. Silicon was applied at the rates of 0 kg/0.1ha(control), 40 kg/0.1ha, and 80 kg/0.1ha throughout the course of experiment. Plant growth parameters were enhanced by the application of elevated Si, though plant height and culm length were more favorably affected than the respective dry weights. The plant mineral contents analyzed also increased in treatments where Si was applied without potassium, demonstrating that Si application promotes the absorption of these minerals in rice crops. The endogenous gibberellins measured in our study showed that $GA_1$ is the only bioactive GA form present in rice seedlings. The endogenous $GA_1$ and its precursor $GA_{20}$ contents increased after Si application. However, this increase in endogenous $GA_1$ and $GA_{20}$ contents, and plant growth parameters were different according to the rice cultivars. Our results indicate that Si is a beneficial element in rice nutrition and that different cultivars of Oryza sativa show differential responses to Si nutrition in terms of their growth and development.

• 농약과학회지
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• 제13권4호
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• pp.262-266
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• 2009

유채 근권으로 부터 분리된 고활성 근권균 Burkholderia pyrrocinia 13-1는 유채의 생육을 촉진 시키며 특히 저온조건에서의 식물 생육이 우수하다. 이 균주의 유채 처리는 저온조건에서 뿌리의 발근을 좋게 하며 지상부 생육도 다른 대조 균주처리 보다 우수하다. 근권미생물이 가지는 유용 기능 중 식물의 영양 흡수와 병 저항성에 관여하는 시드로포어의 생성, 항균활성과 토양 중 불용화 인산인 칼슘포스페이트를 가용화시켜 식물의 흡수를 돕는 용해 능력이 우수하였다. 이와 같은 특성은 식물의 생육을 촉진시키는 근권세균의 활성기작으로 식물생육 촉진용으로 유채재배에 적용할 수 있을 것으로 기대된다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제15권3호
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• pp.15-26
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• 2010

The contaminated soils near abandoned mine area can threaten human's health and natural ecosystems through multiple pathways. Remediation of contaminated soil using physicochemical technologies are expensive and destructive of soil environments. On the other hand, environmentally friendly approach that maximize biological remediation, that is, phytoremediation, attracts attention as a low carbon green growth technology. This research is a field demonstration study, focused on the enhanced phytoremediation by bioaugmenting PGPR(Plant Growth Promoting Rhizobacteria)that is helpful on the growth of and heavy metal removal by Echinochloa frumentacea, at a Zn contaminated paddy soil near SamBo mine at Hwasung, Kyunggi. The results showed that the zinc removal by the plant with PSM(Phosphate Solubilizing Bacteria), a kind of PGPR, was three times higher than that by the control. The results are valuable as it is a result from the field-scale technology demonstration. The results also implies that application of PGPR can enhance heavy metal removal from contaminated soil in full scale phytoremediation using Echinochloa frumentacea.

• Journal of Photoscience
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• 제9권2호
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• pp.94-97
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• 2002

Light is one of the most important environmental factors that influence plant growth and development. It does not function independently but exerts its role through coordinated interactions with intrinsic developmental programs, such as hormonal regulation. One typical example is hypocotyl growth in which light signals are modulated through growth hormones. However, the underlying molecular mechanisms are largely unknown. We demonstrated that brassinosteroids play an important role in the light signal transduction in etiolated hypocotyl growth. A light-responsive Ras-like G-protein, Pra2 from pea, physically and functionally interacts with a cytochrome P450 that specifically catalyzes C-2 hydroxylation in brassinosteroid biosynthesis. The cytochrome P450 expression, along with Pra2, is induced in the dark and predominantly localized in the rapidly elongating zone of etiolated pea epicotyls. Transgenic plants with a reduced level of Pra2 exhibit a dark-specific dwarfism, which is completely rescued by brassinosteroid application. On the contrary, overexpression of the cytochrome P450 results in enhanced hypocotyl growth even in the light, which phenocopies the etiolated hypocotyl growth. It is therefore envisioned that Pra2 is a molecular switch that mediates the crosstalk between light and brassinosteroids in the etiolation process.

• Journal of Applied Biological Chemistry
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• 제57권2호
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• pp.153-157
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• 2014

Plant-growth-promoting rhizobacteria can affect plant growth by various direct and indirect mechanisms. This study was conducted to determine the ability of some rhizobacterial strains to enhance the seed germination of Lactuca sativa (lettuce) and Raphanus sativus (radish). Seeds were inoculated using a spore suspension ($1{\times}10^7cfumL^{-1}$) and incubated in a growth chamber at $28^{\circ}C$ under dark conditions and 65% RH. Azotobacter chroococcum and LAP mix inoculation increased the plumule length of L. sativa by 1.3, 0.8, and 0.7 cm, respectively, in comparison to the uninoculated control. Pseudomonas putida showed an increase of only 0.6 cm in plumule length when compared to the control. Inoculation of A. chroococcum, P. putida, and LAP mix enhanced the seed germination rate of R. sativus, by 10, 5, and 30%, respectively, in comparison with the uninoculated seeds. The results demonstrated that the inoculation of seeds by select rhizobacterial strains showed remarkable enhancement to the radicle length of lettuce and radish seedlings.

• 한국작물학회지
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• 제44권2호
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• pp.176-179
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• 1999

Trinexapac-ethyl[ 4-(cyclopropyl- $\alpha$ -hydroxy-methylene)-3,5-dioxocyclohexane carboxylic acid ethylester] is a growth-retardant for plants by inhibiting a key step in biosynthesis of GA. A treatment of trinexapacethyl generally induces a reduction in vegetative growth and also inhibits heading. In addition, the trinexapacethyl was known to enhance the freeze-tolerance in annual bluegrass, however, the mechanism is not known yet. One possible reason for the enhanced freeze-tolerance may be the antifreeze protein known to be accumulated in intercellular space of the leaf during cold acclimation. In order to see the possible in-duction of the synthesis of antifreeze proteins by trinexacpacethyl, the apoplastic proteins extracted from Kentucky bluegrass treated with trinexapacethyl were analyzed by SDS-PAGE and the presence of the antifreeze protein was observed. In addition, western analysis showed the identity of the protein induced by both a cold acclimation and a trinexapacethyl treatment. It appears that an enhanced freeze-tolerance of the turf grass by trinexapacethyl is due to the synthesis and/or accumulation of the antifreeze protein similar to the enhanced freeze tolerance induced by cold acclimation.