• Journal of Microbiology and Biotechnology
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• 제3권4호
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• pp.238-243
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• 1993

In the suspension cultures of Eschscholtzia californica, phytohormone effects showed that alkaloid production was increased by IAA treatment without kinetin in both volumetric and specific way. Kinetin, however, suppressed alkaloid accumulation. Addition of ethephon inhibited cell growth. However, it enhanced the alkaloid production significantly in both volumetric and specific way. IAA promoted alkaloid production during elicitation. The highest alkaloid accumulation was observed at 5 $\mu$ M of IAA. Ethephon also enhanced alkaloid production during elicitation. The highest alkaloid formation was observed at 460 mg/l of ethephon with elicitation. Elicitation with ethephon, however, altered cell growth and the pattern of benzophenanthridine alkaloids production.

• Korean Chemical Engineering Research
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• 제58권4호
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• pp.514-523
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• 2020

이동성이 없는 식물은 주위 환경에서 다양한 형태의 스트레스를 받게 되는데 이를 대응하기 위한 방어 기작으로 스트레스 저항성 단백질과 조절 단백질이 생성된다. 앱시스산은 이러한 신호전달 역할을 하는 호르몬 분자로 잘 알려져 있으며, 잎의 노화, 종자의 휴면 등 식물의 생리적 반응에도 관여한다. 특히 식물이 아닌 동물, 조류(algae) 등 다른 생물계에서도 다양한 기능을 수행하는 것으로 밝혀졌다. 본 총설에서는 앱시스산의 생합성 및 신호전달 과정 그리고 그 기능에 대하여 조사하였고, 농생명공학, 의생명공학, 산업생명공학을 포함한 다양한 생명공학분야에서 앱시스산을 활용한 작물량 증대, 질병 치료제 개발, 바이오에너지 생산 등 최신 응용 연구 및 산업적 활용에 대한 동향을 살펴보았다.

• Journal of Ginseng Research
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• 제9권1호
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• pp.42-53
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• 1985

This study was carried out to obtain the basic information about the large scale propagation of ginseng (Panax ginseng C.A. Meyer). Therefore, the stem cuttings of 1-year old ginseng, treated with various concentrations of plant growth regulators for 5 seconds (quick dipping) and 24 hours (prolonged soaking), were cultured. The root formation of stem cuttings was varied with the concentrations, kinds, and treatment methods of plant growth regulators. Besides normal-looking roots various malformed roots were observed. In the prolonged soaking method, the culture of stem cuttings, treated with 10 ppm of IBA or NAA, resulted in profuse root regeneration. And stem cuttings, in quick dipping method, treated with 2000 ppm of IBA or NAA resulted in more excellent root regeneration. In general, IBA was more vigorous for the root formation than NAA, The treatment with 50 ppm kinetin or 100 ppm BA brought good result for the retardation of senescence of stem cuttings and BA treatment was more effective than kinetin. As for the saponin content of roots derived from stem cutting culture, the roots, formed by non-treatment of growth regulators, were higher in saponin content than those formed by treatment of growth regulators.

• ALGAE
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• 제31권3호
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• pp.267-276
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• 2016

Microalgae are currently a very promising source of biomass and triacylglycerol (TAG) for biofuels. In a previous study, we identified Chlorella saccharophila as a suitable source of oil for biodiesel production because it showed high biomass and lipid content with an appropriate fatty acid methyl esters profile. To improve the TAG accumulation in C. saccharophila, in this study we evaluated the effect of abscisic acid (ABA) addition on cell concentration, lipid content and TAG production in this microalga. First, we evaluated the effects of four ABA concentrations (1, 4, 10, and 20 μM) added at the beginning of a single-stage cultivation strategy, and found that all concentrations tested significantly increased cell concentration and TAG content in C. saccharophila. We then evaluated the addition of 1 μM ABA during the second stage of a two-stage cultivation strategy and compared it with a nitrogen deficiency treatment (ND) and a combination of ND and ABA (ND + ABA). Although ABA alone significantly increased lipid and TAG contents compared with the control, ND showed significantly higher TAG content, and ND + ABA showed the highest TAG content. When comparing the results of both strategies, we found a superior response in terms of TAG accumulation with the addition of 1 μM ABA at the beginning of a single-stage cultivation system. This strategy is a simple and effective way to improve the TAG content in C. saccharophila and probably other microalgae as a feedstock for biodiesel production.

• Molecules and Cells
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• 제37권11호
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• pp.795-803
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• 2014

To withstand ever-changing environmental stresses, plants are equipped with phytohormone-mediated stress resistance mechanisms. Salt stress triggers abscisic acid (ABA) signaling, which enhances stress tolerance at the expense of growth. ABA is thought to inhibit the action of growth-promoting hormones, including brassinosteroids (BRs). However, the regulatory mechanisms that coordinate ABA and BR activity remain to be discovered. We noticed that ABA-treated seedlings exhibited small, round leaves and short roots, a phenotype that is characteristic of the BR signaling mutant, brassinosteroid insensitive1-9 (bri1-9). To identify genes that are antagonistically regulated by ABA and BRs, we examined published Arabidopsis microarray data sets. Of the list of genes identified, those upregulated by ABA but downregulated by BRs were enriched with a BRRE motif in their promoter sequences. After validating the microarray data using quantitative RT-PCR, we focused on RD26, which is induced by salt stress. Histochemical analysis of transgenic Arabidopsis plants expressing RD26pro:GUS revealed that the induction of GUS expression after NaCl treatment was suppressed by co-treatment with BRs, but enhanced by co-treatment with propiconazole, a BR biosynthetic inhibitor. Similarly, treatment with bikinin, an inhibitor of BIN2 kinase, not only inhibited RD26 expression, but also reduced the survival rate of the plant following exposure to salt stress. Our results suggest that ABA and BRs act antagonistically on their target genes at or after the BIN2 step in BR signaling pathways, and suggest a mechanism by which plants fine-tune their growth, particularly when stress responses and growth compete for resources.

• Molecules and Cells
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• 제39권9호
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• pp.705-713
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• 2016

The efficiency of Agrobacterium-mediated transformation in plants depends on the virulence of Agrobacterium strains, the plant tissue culture conditions, and the susceptibility of host plants. Understanding the molecular interactions between Agrobacterium and host plant cells is crucial when manipulating the susceptibility of recalcitrant crop plants and protecting orchard trees from crown gall disease. It was discovered that Arabidopsis voltage-dependent anion channel 1 (atvdac1) mutant has drastic effects on Agrobacterium-mediated tumorigenesis and growth developmental phenotypes, and that these effects are dependent on a Ws-0 genetic background. Genetic complementation of Arabidopsis vdac1 mutants and yeast porin1-deficient strain with members of the AtVDAC gene family revealed that AtVDAC1 is required for Agrobacterium-mediated transformation, and there is weak functional redundancy between AtVDAC1 and AtVDAC3, which is independent of porin activity. Furthermore, atvdac1 mutants were deficient in transient and stable transformation by Agrobacterium, suggesting that AtVDAC1 is involved in the early stages of Agrobacterium infection prior to transferred-DNA (T-DNA) integration. Transgenic plants overexpressing AtVDAC1 not only complemented the phenotypes of the atvdac1 mutant, but also showed high efficiency of transient T-DNA gene expression; however, the efficiency of stable transformation was not affected. Moreover, the effect of phytohormone treatment on competence to Agrobacterium was compromised in atvdac1 mutants. These data indicate that AtVDAC1 regulates the competence of Arabidopsis to Agrobacterium infection.

• 미생물학회지
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• 제49권1호
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• pp.46-50
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• 2013

일부 근권세균은 ACC deaminase를 생성하여 식물의 생장을 저해하고 노화를 촉진시키는 식물호르몬 에틸렌의 수준을 낮춤으로써 스트레스 조건 하의 식물의 생장을 지속시킨다. 본 연구에서는 모래사장에서 자라는 식물의 근권에서 ACC deaminase를 생성하는 세균 균주들을 분리하여 16S rDNA 염기서열 분석을 통해 Escherichia hermannii m-2, Enterobacter asburiaem-4, Pseudomonas thivervalensis BD2-26, and Pseudomonas brassicacearum subsp. neoaurantiaca BD3-35로 동정하였다. BD3-35 균주는 이들 중 가장 높은 ACC deaminase 활성, 20.26 ${\alpha}$-ketobutyrate ${\mu}M/mg$ protein/h을 나타내었다. 균주 BD3-35와 BD2-26는 식물호르몬 시토키닌, m-4는 옥신 IAA와 IBA, 그리고 균주 m-2는 ABA 생성능을 가졌다. 이 균주들은 모두 토마토종자 발아 시 유묘의 뿌리신장을 유의성 있게 촉진하였다. 또한 7일간 자란 토마토 식물에 처리하고 가뭄 스트레스 하에서 7일간 재배하였을 때 비접종 대조군에 비해 균주 BD3-35, m-2와 m-4는 토마토 뿌리의 길이를 각각 14, 15와 35% 증가시켰으며, m-2, BD2-26와 BD3-35는 토마토 식물의 건조중량을 각각 22, 33과 68% 증가시켰다. 따라서 이 균주들은 가뭄 스트레스 하의식물을 위한 미생물 비료로 사용될 수 있는 가능성을 보였다.

• 한국약용작물학회지
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• 제13권1호
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• pp.57-62
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• 2005

인삼에 염류내성을 증진시키기 위해서 Arobidopsis에서 분리한 SAL1 (3‘(2’),5‘-bis-phosphate nucleotidase) 유전자를 Agrobacterium Tumefaciens을 이용하여 인삼자엽으로부터 형질 전환체를 유도하였다. Agrobacterium 과 공동배양 후 식물호르몬 무첨가 선발배지 (kanamycin 100 mg/l)에 치상한 결과 10%미만의 자엽에서 형질전환 인삼체세포배가 발생되었으나, Agrobacterium과 공동배양 후 1.0 mg/l 2.4-D와 0.5 mg/l kinetin의 식물호르몬을 첨가한 배지에 옮겨준 경우에는 74%의 형질전환율을 보였다. 발생한 체세포배는 초기에 250 mg/l 의 cefotaxime이 첨가된 MS배지에서 3주간 배양한 후 100 mg/l kanamycin과 250 mg/l cefotaxime이 첨가된 MS배지에 계대배양하여 선발하였다. 자엽단계로 발달한 체세포배들은 발아시키기 위해서 50 mg/l kanamycin과 10 mg/l 지베렐린이 첨가된 MS 배지로 옮겨 선발하였다. Kanamycin 첨가배지에서 선발된 체세포배들은 특이 프라이머로 PCR 증폭을 통하여 최종적으로 형질전환체를 확인하였으며, 줄기와 뿌리가 잘 발달된 형질전환체들은 성공적으로 토양에 순화시켰다.

• Journal of Microbiology and Biotechnology
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• 제16권10호
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• pp.1622-1628
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• 2006

Bacteria from the Methylobacterium genus, called pink-pigmented facultative methylotrophic bacteria (PPFMs), are common inhabitants of plants, potentially dominating the phyllosphere population, and are also encountered in the rhizosphere, seeds, and other parts of plants, being versatile in nature. The consistent success of the Methylobacterium plant association relies on methylotrophy, the ability to utilize the one-carbon compound methanol emitted by plants. However, the efficiency of Methylobacterium in plant growth promotion could be better exploited and thus has attracted increasing interest in recent years. Accordingly, the present study investigated the inoculation effects of Methylobacterium sp. strains CBMB20 and CBMB 110 on seed imbibition to tomato and red pepper on the growth and accumulation of phytohormone levels under gnotobiotic conditions. Seeds treated with the Methylobacterium strains showed a significant increase in root length when compared with either the uninoculated control or Methylobacterium extorquens $miaA^-$ knockout mutanttreated seeds. Extracts of the plant samples were used for indole-3-acetic acid (IAA), trans-zeatin riboside (t-ZR), and dihydrozeatin riboside (DHZR) assays by immunoanalysis. The treatment with Methylobacterium sp. CBMB20 or CBMB 110 produced significant increases in the accumulation of IAA and the cytokinins t-ZR and DHZR in the red pepper extracts, whereas no IAA was detected in the tomato extracts, although the cytokinin concentrations were significantly increased. Therefore, this study proved that the versatility of Methylobacterium as a plant-growth promoting bacteria could be better exploited.

• 한국잡초학회지
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• 제18권4호
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• pp.295-303
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• 1998

잡초(雜草)의 휴면(休眠)은 불량(不良)한 외부조건(外部條件)에 적응하기 위한 기작으로서 잡초방제(雜草防除)에 있어서 많은 난점을 발생시킨다, 잡초종(雜草種)들의 발아(發芽)와 휴면(休眠) 현상을 특성을 규명하기 위하여 우리나라에 우점(優占)는 잡초(雜草)50여종의 잡초(雜草)에 대하여 화학물질(化學物質)처리와 종자매몰(種子埋沒)을 실시한 결과는 다음과 같다. 1. $KNO_3$, thiourea, KOH, $H_2O_2$ 등의 화학물질(化學物質)처리는 휴면타파(休眠打破)보다는 비휴면(非休眠) 종자(種子)의 발아촉진(發芽促進)에 효과가 있었다. 2. Pectinase는 강아지풀, 금강아지풀, 방동사니 대가리, 개구리자리 등의 휴면타파(休眠打破)에 효과가 있었다. 3. $GA_3$는 효과는 크지 않았으나 왕바랭이와 개여뀌, 개구리자리의 휴면타파(休眠打破)에 효과가 있었다. 4. 7주(週)이상 토양(土壤)에 매몰(埋沒)되었던 잡초종자(雜草種子)의 발아율(發芽率)은 크게 증가하였으며 변온(變溫)은 발아율(發芽率)에 상승작용(相乘作用)을 일으켰다. 그러나 매몰(埋沒)기간이 지속되면 발아율(發芽率)이 낮아져 이차휴면(二次休眠)에 들어가는 것으로 추정되었다. 특히 마디풀과의 Persicaria속(屬)과 명아주과의 Chenopodium속의 식물은 토양(土壤) 매몰(埋沒)에 의한 휴면(休眠) 타파(打破) 정도가 크게 나타났다.