• Korean Journal Plant Pathology
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• v.11 no.2
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• pp.173-178
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• 1995

동물계에서 항바이러스와관련된 dsRNA 의존성 인산화 효소(PKR)의 유전자를 식물체에서 발현시킬 경우 PKR에 의한 단백질합성 및 식물바이러스의 증식조절 가능성에 대한 기초자료를 확보하기 위하여 사람에서 분리된 PKR cDNA를 Agrobacterium 방법에 의하여 연초식물체(Nicotiana tabacum cv. Xanthi-nc)로 형질전환시켰다. HindIII/PstI처리에 의해 얻어지는 약 1.8kb의 phPKR cDNA절편을 일련의 유전자 조작 방법을 통하여 식물발현벡터인 pBI121에 도입하여, p12168을 재조합하였다. 이를 A. tumefaciens LBA 4404에 형질전환시켜 연초식물체형질 전환에 이용하였다. 2mg/l BA와 0.5mg/l NAA가 포함되고 100$\mu\textrm{g}$/ml의 kanamycin이 첨가된 MS배지에서 shooting시킨 후 phytohormone이 첨가되지 않은 MS배지상에서 rooting을 시켜 형질전환 연초식물체를 얻었으며, 형질전환식물체는 정상식물체와 유사한 생육양상을 나타내었다. 형질전환식물체의 유전자도입은 hPKR cDNA의 전사부여는 RT-PCR 방법에 의하여 확인되었다.

• Journal of Ginseng Research
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• v.9 no.1
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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.

• Korean Journal of Plant Resources
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• v.11 no.2
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• pp.176-176
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• 1998

This study was carried out to obtain the information for growth characteristics of crown gall tumor and hairy root transformed by Agrobacterium spp,. on the media with phytohormones, casein hydrolysate and activated charoal. Crown gall tumors and hairly roots were formed respectively on potato tuber discs infected by tumerfaciens A ch 5 and A.rhizogenes ATCC15834. These tumors and roots could be grown on the phytohormone free media. PCR analysis of Rol C and Vir C gene fragments confirmed that crown gall root was prompted on the medium containing 2,4-D 2mg/l with casein hydrolysate lg/l. The survival ration of crown gall tumor callus derived from potato increased on medium containing the activated charcoal 0.5∼0.2mg/l because of the prevention, on the other hand, hairly roots were necrosis on the same medium. Callus derived from hairly root were excellently grown for a short time by suspension culture on liquid medium containing 2.4-d 2mg/L and casein hydrolysate lg/l.

• Korean Journal of Plant Resources
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• v.11 no.2
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• pp.179-187
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• 1998

This study was carried out to obtain the information for growth characteristics of crown gall tumor and hairy root transformed by Agrobacterium spp,. on the media with phytohormones, casein hydrolysate and activated charoal. Crown gall tumors and hairly roots were formed respectively on potato tuber discs infected by tumerfaciens A ch 5 and A.rhizogenes ATCC15834. These tumors and roots could be grown on the phytohormone free media. PCR analysis of Rol C and Vir C gene fragments confirmed that crown gall root was prompted on the medium containing 2,4-D 2mg/l with casein hydrolysate lg/l. The survival ration of crown gall tumor callus derived from potato increased on medium containing the activated charcoal 0.5∼0.2mg/l because of the prevention, on the other hand, hairly roots were necrosis on the same medium. Callus derived from hairly root were excellently grown for a short time by suspension culture on liquid medium containing 2.4-d 2mg/L and casein hydrolysate lg/l.

• Journal of Plant Biology
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• v.31 no.2
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• pp.121-130
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• 1988

In order to clarify effects of phytohormones on the viability and the cell wall regeneration of protoplasts isolated from Nicotiana tobacum L. var. BY4, protoplasts isolated from mesophyll tissue were cultured on the Murashige-Skoog liquid media supplemented with auxin(2, 4-D, NAA, IAA) and/or cytokinin (kinetin, BAP, 2ip). Viability of protopplasts was higher in the culture medium containing auxin and cytokinin, especially in the combination of 2, 4-D and BAP. The effectual cell wall regeneration of protolasts was observed when theprotoplasts were cultrued on the medium supplemented with auxin alone, especially with IAA. Cell wall regernation started from 2-3 days after culture and was not detected at budding regions. When the protoplasts were cultured on the phytohormone-free medium, the viability of protoplasts dramatically decreased 4 days after culture.

• Plant Resources
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• v.8 no.3
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• pp.286-292
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• 2005

Shoot induction system was developed in the recalcitrant plant species, Brassica rapa ssp. rapifera by using optimum selection of profit organ, phytohormone combination, seedling age and kind of culture container. Out of in vitro cultured leaf segment, petiole, hypocotyl, and cotyledon with petiole, only cotyledon with petiole derived from 4 day-old seedlings induced multiple shoot. The optimum combination of auxin and cytokinin for the multiple shoot induction was MS medium containing 5mg/L BA and 0.5mg/L NAA. The major factors for multiple shoot propagation were part of plant organ, age of seedling, and ratio of auxin and cytokinin. In addition, shoot regeneration was promoted in the 100ml Erlenmeyer flask compared with the $90mm{\times}20mm$ Petri-dish. The induced shoots formed roots easy on MS medium containing 0.1mg/L IBA and the whole plants were successfully cultivated in soil.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.46-50
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• 2013

Some rhizobacteria producing 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase can make plant to continue growth under the stress conditions through lowering the level of phytohormone, ethylene which inhibits the plant growth and accelerates plant aging. In this study, some rhizobacteria producing ACC deaminase have been isolated from the rhizosphere of plants grown at sand beaches, and identified as Escherichia hermannii m-2, Enterobacter asburiae m-4, Pseudomonas thivervalensis BD2-26 and Pseudomonas brassicacearum subsp. neoaurantiaca BD3-35 through sequencing of 16S rRNA genes. Strain BD3-35 showed the highest activity of ACC deaminase among the isolates, 20.26 ${\alpha}$-ketobutyrate ${\mu}M/mg$ protein/h. Strains BD3-35 and BD2-26 secreted a phytohormone cytokinin, and strains m-4 and m-2 could produce auxin and abscisic acid, respectively. When these bacteria were applied to the 7-day old tomato plant under drought stress for 7 days, strains BD3-35, m-2, and m-4 increased the length of tomato root by 14, 15, and 35%, respectively, and strains m-2, BD2-26 and BD3-35 increased the dry weight of tomato plant by 22, 33, and 68%, respectively compared to the uninoculated control tomatoes. Therefore, these rhizobacteria may be utilized as a microbial fertilizer for the plants under drought stress.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.4
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• pp.266-287
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• 2004

The non infecting, plant associated bacteria have attracted increased attention for stimulating plant growth and as environmental friendly plant protecting agents. Pink-pigmented facultatively methylotrophic bacteria (PPFMs), classified as Methylobacterium spp., are persistent colonizers of plant leaf surfaces. As the leaves of most or all plants harbor PPFMs that utilize leaf methanol as their sole source of carbon and energy, which is a specific attribute of the genus Methylobacterium. Although they are not well known, these bacteria are co-evolved, interacting partners in plant metabolism. This claim is supported, for example, by the following observations: (1) PPFMs are seed-transmitted, (2) PPFMs are frequently found in putatively axenic cell cultures, (3) Low numbers of seed-borne PPFMs correlate with low germinability, (4) Plants with reduced numbers of PPFM show elevated shoot/root ratios, (5) Foliar application of PPFMs to soybean during pod fill enhances seed set and yield, (6) Liverwort tissue in culture requires PPFM-produced vitamin B12 for growth, (7) treated plants to suppress or decrease disease incidence of sheath blight caused by Rhizoctonia solani in rice, and (8) the PPFM inoculation induced number of stomata, chlorophyll concentration and malic acid content, they led to increased photosynthetic activity. Methylobacterium spp. are bacterial symbionts of plants, shown previously to participate in plant metabolism by consuming plant waste products and producing metabolites useful to the plant. There are reports that inform about the beneficial interactions between this group of bacteria and plants. Screening of such kind of bacteria having immense plant growth promoting activities like nitrogen fixation, phytohormone production, alleviating water stress to the plants can be successfully isolated and characterized and integration of such kind of organism in crop production will lead to increased productivity.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.714-719
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• 2013

The bent peduncle phenomenon (BPP) is known as a kind of physiological disorders found in cut rose plants, which causes the reduction of cut flower yields. As yet unknown mechanisms, however, it has not been easy to find solutions for BPP. To address this challenge, this study was conducted to investigate the characteristics of floral morphology, growth, and endogenous phytohormone level of BPP shoots in cut rose plants (Rosa hybrida L. 'Beast'). Morphological observation confirmed the fact that BPP was accompanied by the early formation and being phyllody of a specific sepal among five sepals, which gave rise to peduncle bending in the upper part of the phyllody with fasciation. Year-round BPP frequency in 'Beast' cultivar was in the range of 5 to 20% with seasonal change, increasing rapidly with an average temperature rise in summer. Except bent peduncle, the BPP shoots appeared to grow normally in terms of speed and size of floral development in comparison with normal. However, carbohydrate distribution to the floral part in BPP shoots was significantly reduced. The level of endogenous IAA (3-Indoleacetic acid) within the floral part in BPP shoots was highly maintained during floral development, in contrast to normal shoots. $GA_3$ contents were not significantly different between normal and BPP shoots. This study indicates that BPP would be induced by a series of courses: abnormally early formation of a specific sepal relative to high temperature, being phyllody of the sepal with fasciation, and continuous supply of endogenous IAA by phyllody.

• Journal of Life Science
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• v.29 no.11
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• pp.1281-1293
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• 2019

The rhizosphere is the active zone where plant roots communicate with the soil microbiome, each responding to the other's signals. The soil microbiome within the rhizosphere that is beneficial to plant growth and productivity is known as plant growth-promoting rhizobacteria (PGPR). PGPR take part in many pivotal plant processes, including plant growth, development, immunity, and productivity, by influencing acquisition and utilization of nutrient molecules, regulation of phytohormone biosynthesis, signaling, and response, and resistance to biotic- and abiotic-stresses. PGPR also produce secondary compounds and volatile organic compounds (VOCs) that elicit plant growth. Moreover, plant roots exude attractants that cause PGPR to aggregate in the rhizosphere zone for colonization, improving soil properties and protecting plants against pathogenic factors. The interactions between PGPR and plant roots in rhizosphere are essential and interdependent. Many studies have reported that PGPR function in multiple ways under the same or diverse conditions, directly and indirectly. This review focuses on the roles and strategies of PGPR in enhancing nutrient acquisition by nutrient fixation/solubilization/mineralization, inducing plant growth regulators/phytohormones, and promoting growth and development of root and shoot by affecting cell division, elongation, and differentiation. We also summarize the current knowledge of the effects of PGPR and the soil microbiota on plants.