• Journal of Microbiology and Biotechnology
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• 제30권10호
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• pp.1500-1509
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• 2020

Drought is a major abiotic factor and has drastically reduced crop yield globally, thus damaging the agricultural industry. Drought stress decreases crop productivity by negatively affecting crop morphological, physiological, and biochemical factors. The use of drought tolerant bacteria improves agricultural productivity by counteracting the negative effects of drought stress on crops. In this study, we isolated bacteria from the rhizosphere of broccoli field located in Daehaw-myeon, Republic of Korea. Sixty bacterial isolates were screened for their growth-promoting capacity, in vitro abscisic acid (ABA), and sugar production activities. Among these, bacterial isolates YNA59 was selected based on their plant growth-promoting bacteria traits, ABA, and sugar production activities. Isolate YNA59 highly tolerated oxidative stress, including hydrogen peroxide (H₂O₂) and produces superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities in the culture broth. YNA59 treatment on broccoli significantly enhanced plant growth attributes, chlorophyll content, and moisture content under drought stress conditions. Under drought stress, the endogenous levels of ABA, jasmonic acid (JA), and salicylic acid (SA) increased; however, inoculation of YNA59 markedly reduced ABA (877 ± 22 ng/g) and JA (169.36 ± 20.74 ng/g) content, while it enhanced SA levels (176.55 ± 9.58 ng/g). Antioxidant analysis showed that the bacterial isolate YNA59 inoculated into broccoli plants contained significantly higher levels of SOD, CAT, and APX, with a decrease in GPX levels. The bacterial isolate YNA59 was therefore identified as Variovorax sp. YNA59. Our current findings suggest that newly isolated drought tolerant rhizospheric Variovorax sp. YNA59 is a useful stress-evading rhizobacterium that improved drought-stress tolerance of broccoli and could be used as a bio-fertilizer under drought conditions.

• 식물조직배양학회지
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• 제21권6호
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• pp.341-345
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• 1994

식물세포의 기내배양에 의한 ubiquinone 10의 생산연구의 일환으로 Nicotiana tabacum cv Xanthi 품종으로부터 ubiquinone 10의 생성여부을 확인하고, 식물호르몬의 종류와 농도의 조건에 따른 ubiquinone 10의 생산증대를 조사하고자 본 실험을 수행하였다. Xanthi 캘러스 생장은 NAA 및 2,4-D와 혼합처리시 생장이 양호하였으며 NAA 단독처리구에서도 생장량이 증가되었고 암배양보다는 광배양상태에서 더 양호하였다. 또한 HPLC에 의해서 ubiquinone 10의 생성 여부를 조사한 결과 어느 조건에서도 모두 ubiquinone 10이 검출되었다. 식물호르몬에 의한 ubiquinone 10의 함량은 2,4-D와 NAA 혼합처리구에서보다 NAA 0.5 mg/L 단독처리구에서 ubiquinone 10의 함량이 증가되었으며, 특히 IBA 1mg/L와 NAA 0.5 mg/L 혼합처리구에서 더 양호한 경향을 보였고 단위 플라스크당 ubiquinone 10의 생산량도 더 높았다. 그러나 2,4-D 0.5 mg/L와 kinetin 0.5 mg/L 혼합한 처리구에서는 캘러스의 생장량은 비록 적었지만 ubiquinone 10의 함량이 가장 높아 단위 플라스크당 생산량은 제일 높은 경향을 보였다.

• Journal of Plant Biotechnology
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• 제42권3호
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• pp.168-179
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• 2015

We previously identified the rice gene, OsSAP, as an encoder of a highly conserved putative senescence-associated protein that was shown to have anti-apoptotic activity. To confirm the role of OsSAP in inducing abiotic stress tolerance in rice, we introduced OsSAP and AtBI-1, a plant homologue of Bax inhibitor-1, under the control of the CaMV 35S promoter into the rice genome through Agrobacterium-mediated transformation. The OsSAP transformants showed a similar chlorophyll index after salinity treatments with AtBI-1. Furthermore, we compared the effects of salinity stress on leaves and roots by examining the hormone levels of abscisic acid (ABA), jasmonic acid (JA), gibberellic acid (GA3), and zeatin in transformants compared to the control. With the exception of phytohormones, stress-induced changes in hormone levels putatively related to stress tolerance have not been investigated previously. Hormonal level analysis confirmed the lower rate of stress in the transformants compared to the control. The levels of ABA and JA in OsSAP and AtBI-1 transformants were similar, where stress rates increased after one week and decreased after a two week period of drought; there was a slightly higher accumulation compared to the control. However, a similar trend was not observed for the level of zeatin, as the decrease in the level of zeatin accumulation differed in both OsSAP and AtBI-1 transformants for all genotypes during the early period of salinity stress. The GA3 level was detected under normal conditions, but not under salinity stress.

• Journal of Plant Biology
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• 제35권4호
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• pp.371-383
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• 1992

Chlorella ellipsoidea에서 분리한 엽록체의 인지질 생합성과 그의 지방산 조성에 미치는 $10^{-3}M$의 IAA(indole acetic acid)와 $2{\times}10^{-8}M의\;GA_3의$ 효과를 분석하였다. 처리구가 대조구에 비하여 생장률, 총 지질, 인지질 함량이 높은 것으로 나타났으며 특히 $GA_3$ 처리구에서는 phosphatidyl-choline 함량이 높은 것으로 분석되었다. Whole cell system에서의 주요 지방산은 대조구에서는 palmitic acid가 27.43% 였으며 IAA 처리구에서는 linolenic acid가 20.25%로 분석되었다. $GA_3$ 처리구에서는 linolenic acid가 23.17%로 인지질 형성에 이용된 주요 지방산인 것으로 분석되었다. 분리한 엽록체에서는 대조구의 주요 지방산은 palmitic acid가 35.67%로 나타났으며 IAA 처리구에서는 linolenic acid가 24.91%, GA3 처리구에서는 linolenic acid가 22.80%로 인지질 형성에 이용된 주요 지방산으로 분석되었다.

• Journal of Plant Biology
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• 제35권2호
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• pp.135-142
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• 1992

발아시킨 물오리나무(Alnus hirsuta)의 하배축 부위를 절단하여 얻은 떡잎이 포함된 상부를 6% glucose, MS(Murashige and Skoog, 1962) 비타민 혼합체, PVP(polyvinylpyrrolidone) 및 $0-50\;\mu\textrm{M}$이 BAP(6-benzylaminopurine)를 첨가한 NT(Nagata and Takebe, 1971) 무기염배지에서 배양한 결과, $5\;\mu\textrm{M}$이 BAP가 shoot 증식에 가장 적합한 것으로 나타났다. 따라서 이 배지에서 shoot 증식을 계속하여 실험에 사용할 200여개의 shoot를 확립하였다. Shoot 증식에 미치는 무기염류와 탄소원의 영향을 조사한 결과 탄소원에 무관하게 NT 무기염이 MS 무기염에 비해 3-12배의 증식을 나타냈으나 NT 무기염배지에서 탄소원은 특별한 차이를 보여주지 않았다. 발근에 미치는 NT 무기염, sucrose, IBA의 농도에 따른 영향을 조사한 결과 1/4-1/2 농도의 NT 무기염, 3%의 sucrose, $1-8\;\mu\textrm{M}$의 IBA에서 100% 가까운 발근율을 보였으며 뿌리발달도 양호하였다. 발근된 개체를 토양에 이식하고 습도를 점진적으로 낮추면서 적응시키면 거의 100%의 생존율을 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제30권5호
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• pp.717-725
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• 2020

The use of plant growth-promoting rhizobacteria is economically viable and environmentally safe for mitigating various plant stresses. Abiotic stresses such as flood and drought are a serious threat to modern agriculture. In the present study, the indole-3-acetic acid-producing rhizobacterium R. sphaeroides KE149 was selected, and its effects on the growth of adzuki bean plants under flood stress (FS) and drought stress (DS) were investigated. IAA quantification of bacterial pure culture revealed that KE149 produced a significant amount of IAA. Moreover, KE149 inoculation notably decreased stress-responsive endogenous abscisic acid and jasmonic acid and increased salicylic acid in plants under DS and FS. KE149 inoculation also increased proline under DS and methionine under FS. In addition, KE149 inoculation significantly increased the levels of calcium (Ca), magnesium (Mg), and potassium (K) while lowering the sodium (Na) content in the plant shoot under stress. KE149-treated plants had markedly greater root length, shoot length, stem diameter, biomass, and higher chlorophyll content under both normal and stressed conditions. These results suggest that KE149 could be an efficient biofertilizer for mitigating water stress.

• 식물병연구
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• 제21권3호
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• pp.161-179
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• 2015

식물은 다양한 병원성 미생물에 대하여 효과적인 방어 기제를 발전시켜 왔다. 최근 유전체와 다중 오믹스 기술의 발전은 우리에게 미생물 인자에 의한 식물 면역을 폭넓게 이해할 수 있는 단초를 제공해 주었다. 하지만 아직까지는 이러한 기술을 병 방제 전략에 이용한 적은 많지 않다. 그래서 본 리뷰에서 식물 면역의 기본 개념을 소개하고 최근 얻어진 결과들을 소개하였다. 덧붙여 이미 논문에서 발표된 진균, 세균, 바이러스 유래 결정인자에 의한 생물적 방제 가능한 방법에 대해 기술하였다. 특히 미생물 결정인자인 chitin, glucan, LPS/EPS, 미생물분자패턴, 항생제, 식물유사호르몬, AHLs, harpin, 비타민, 휘발성물질에 대한 결과를 자세하게 기술하였다. 이 리뷰를 통하여 많은 과학자들과 농민들이 미생물 결정인자 기반의 생물적 방제에 대한 지식이 폭넓어지고, 다양한 미생물 결정 인자가 앞으로 농업현장의 종합적인 병방제 전략의 하나로 자리매김하기를 바란다.

• Journal of Ginseng Research
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• 제41권3호
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• pp.419-427
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• 2017

Background: Glycosylation of natural compounds increases the diversity of secondary metabolites. Glycosylation steps are implicated not only in plant growth and development, but also in plant defense responses. Although the activities of uridine-dependent glycosyltransferases (UGTs) have long been recognized, and genes encoding them in several higher plants have been identified, the specific functions of UGTs in planta remain largely unknown. Methods: Spatial and temporal patterns of gene expression were analyzed by quantitative reverse transcription (qRT)-polymerase chain reaction (PCR) and GUS histochemical assay. In planta transformation in heterologous Arabidopsis was generated by floral dipping using Agrobacterium tumefaciens (C58C1). Protein localization was analyzed by confocal microscopy via fluorescent protein tagging. Results: PgUGT72AL1 was highly expressed in the rhizome, upper root, and youngest leaf compared with the other organs. GUS staining of the promoter: GUS fusion revealed high expression in different organs, including axillary leaf branch. Overexpression of PgUGT72AL1 resulted in a fused organ in the axillary leaf branch. Conclusion: PgUGT72AL1, which is phylogenetically close to PgUGT71A27, is involved in the production of ginsenoside compound K. Considering that compound K is not reported in raw ginseng material, further characterization of this gene may shed light on the biological function of ginsenosides in ginseng plant growth and development. The organ fusion phenotype could be caused by the defective growth of cells in the boundary region, commonly regulated by phytohormones such as auxins or brassinosteroids, and requires further analysis.

• Molecules and Cells
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• 제27권2호
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• pp.217-223
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• 2009

Development of symbiotic root nodules in legumes involves the induction and repression of numerous genes in conjunction with changes in the level of phytohormones. We have isolated several genes that exhibit differential expression patterns during the development of soybean nodules. One of such genes, which were repressed in mature nodules, was identified as a putative aldo/keto reductase and thus named Glycine max aldo/keto reductase 1 (GmAKR1). GmAKR1 appears to be a close relative of a yeast aldo/keto reductase YakC whose in vivo substrate has not been identified yet. The expression of GmAKR1 in soybean showed a root-specific expression pattern and inducibility by a synthetic auxin analogue 2,4-D, which appeared to be corroborated by presence of the root-specific element and the stress-response element in the promoter region. In addition, constitutive overexpression of GmAKR1 in transgenic soybean hairy roots inhibited nodule development, which suggests that it plays a negative role in the regulation of nodule development. One of the Arabidopsis orthologues of GmAKR1 is the ARF-GAP domain 2 protein, which is a potential negative regulator of vesicle trafficking; therefore GmAKR1 may have a similar function in the roots and nodules of legume plants.

• Journal of Microbiology and Biotechnology
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• 제21권7호
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• pp.686-696
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• 2011

To deal with pathogens, plants have evolved sophisticated mechanisms including constitutive and induced defense mechanisms. Phytohormones play important roles in plant growth and development, as well as in the systemic response induced by beneficial and pathogen microorganisms. In this work, we identified an Aspergillus ustus isolate that promotes growth and induces developmental changes in Solanum tuberosum and Arabidopsis thaliana. A. ustus inoculation on A. thaliana and S. tuberosum roots induced an increase in shoot and root growth, and lateral root and root hair numbers. Assays performed on Arabidopsis lines to measure reporter gene expression of auxin-induced/ repressed or cell cycle controlled genes (DR5 and CycB1, respectively) showed enhanced GUS activity, when compared with mock-inoculated seedlings. To determine the contribution of phytohormone signaling pathways in the effect elicited by A. ustus, we evaluated the response of a collection of hormone mutants of Arabidopsis defective in auxin, ethylene, cytokinin, or abscisic acid signaling to the inoculation with this fungus. All mutant lines inoculated with A. ustus showed increased biomass production, suggesting that these genes are not required to respond to this fungus. Moreover, we demonstrated that A. ustus synthesizes auxins and gibberellins in liquid cultures. In addition, A. ustus induced systemic resistance against the necrotrophic fungus Botrytis cinerea and the hemibiotrophic bacterium Pseudomonas syringae DC3000, probably through the induction of the expression of salicylic acid, jasmonic acid/ethylene, and camalexin defense-related genes in Arabidopsis.