• Journal of Plant Biotechnology
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• v.30 no.1
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• pp.13-18
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• 2003

This study was carried out to investigate the expression patterns of foreign gene that controlled by tuber-specific patatin promoter in transgenic potatoes. Potato leaf disc cultured in vitro were transformed by the Agrobacterium strain LBA4404 containing pBl121 or pATGUS from potato cv. Desiree. In order to select the transgenic lines, gene-specific primers deduced from the NPTII were synthesized and used for polymerase chain reaction. The down part of the putative transgenic potatoes was transplanted weekly onto sucrose-enriched medium to accelerate the microtuber formation. RNA gel blot analysis was performed on the total RNAs obtained from tuber that had been harvested at a week interval. Also, histochemical assay was observed in the explants transformed with either pBI121 or pATGUS. Results showed that the transgenic plant containing pATGUS expressed GUS transcripts mainly at the tuber, not in stem, with the highest expression level in 5 weeks-grown microtubers. In contrast to pATGUS plants, the transformed plants with pBI121 showed an equal expression pattern throughout the whole developing stages. Consistent with RNA gel blot analysis, histochemical GUS staining and enzyme activity exhibited pATGUS transcripts were at the highest level in 5 weeks cultures. From these results, we suggest that the best stage to analyze the foreign gene introduced by patatin promoter into potato plants is at 5 weeks cultures after tuber formation.

• The Plant Pathology Journal
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• v.30 no.3
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• pp.254-260
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• 2014

Potato Rpi-blb2 encodes a protein with a coiled-coil-nucleotide binding site and leucine-rich repeat (CC-NBSLRR) motif that recognizes the Phytophthora infestans AVRblb2 effector and triggers hypersensitive cell death (HCD). To better understand the components required for Rpi-blb2-mediated HCD in plants, we used virus-induced gene silencing to repress candidate genes in Rpi-blb2-transgenic Nicotiana benthamiana plants and assayed the plants for AVRblb2 effector. Rpi-blb2 triggers HCD through NbSGT1-mediated pathways, but not NbEDS1- or NbNDR1-mediated pathways. In addition, the role of salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) in Rpi-blb2-mediated HCD were analyzed by monitoring of the responses of NbICS1-, NbCOI1-, or NbEIN2-silenced or Rpi-blb2::NahG-transgenic plants. Rpi-blb2-mediated HCD in response to AVRblb2 was not associated with SA accumulation. Thus, SA affects Rpi-blb2-mediated resistance against P. infestans, but not Rpi-blb2-mediated HCD in response to AVRblb2. Additionally, JA and ET signaling were not required for Rpi-blb2-mediated HCD in N. benthamiana. Taken together, these findings suggest that NbSGT1 is a unique positive regulator of Rpi-blb2-mediated HCD in response to AVRblb2, but EDS1, NDR1, SA, JA, and ET are not required.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.736-741
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• 2000

The abilities of petroleum ether-extracts prepared from 75 plants to inhibit tyrosinase activity were evaluated in reverse micelles composed of isooctane/AOT(100 mM)/phosphate buffer(20 mM, pH 8.0) containing tyrosinase(105.3 units/mL) and 3,4-dihydroxyphenylalanine(0.18 mM). Compared with control which has no plant extracts, garlic could completely inhibit in vitro melanogenesis by tyrosinase, and Chinese quince, sweet potato, onion, radish bud and apple did more than 60%. Lipophilic extracts of medicinal plants and herbs such as rosemary, coriander, cinnamomi ramulus, crataegii fructus, ramulus biotae folium, mume fructus, menthae herba, eucommiae cortex and clove also inhibited tyrosinase activity more than 60%. When the extraction yield of lipophilic materials was considered together with their inhibition effect on tyrosinase, it was possible to select plants of which tyrosinase inhibitors could be produced in high quantity from unit weight. Using reverse micelles, the analysis of the capacity of lipophilic materials to inhibit tyrosinase activity which was difficult up to present could be possible.

• Korean Journal of Organic Agriculture
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• v.23 no.2
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• pp.311-322
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• 2015

The study was conducted on growth and yield of potatoes in a wick hydroponic culture as affected by concentration of aqueous extracts in order to develop natural agricultural resources using Persicaria longiseta. Each 500 ml of distilled water (control) and P. blumei extracts (25%, 50%, 75%, and 100%) was applied to potato plants at 5 d intervals from 1 d after potato transplanting. The potatoes with P. blumei extract emerged 1 d earlier and had 0.3 to 0.4 more stem numbers per plant compared with those of control plot. The plant height was higher in plots with P. blumei extract than in control in early stage of potatoes (50 d), but there was no significant difference observed after mid-stage of potatoes (70 and 90 d). The stem diameter and fresh weight of potatoes estimated a higher values in plots with P. blumei extract than in control plots, although there was no statistical difference. The 100% P. blumei extract increased by up to $13.8kg/m^2$ of potato yield. The numbers of tubers in classes of < 5 g and 5 to 30 g per plant did not show a specific trend among experimental treatments while it in class of > 30 g was much higher in plots with P. blumei extract than in control plot. Accordingly, the P. blumei extract had a positive effect on the growth and yield of potatoes, could be applied as of eco-friendly fertilizers

• Plant Biotechnology Reports
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• v.5 no.4
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• pp.331-344
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• 2011

The well-conserved NBS domain of resistance (R) genes cloned from many plants allows the use of a PCR-based approach to isolate resistance gene analogs (RGAs). In this study, we isolated an RGA (CapRGC) from Capsicum annuum "CM334" using a PCR-based approach. This sequence encodes a protein with very high similarity to Rx genes, the Potato Virus X (PVX) R genes from potato. An evolutionary analysis of the CapRGC gene and its homologs retrieved by an extensive search of a Solanaceae database provided evidence that Rx-like genes (eight ESTs or genes that show very high similarity to Rx) appear to have diverged from R1 [an NBS-LRR R gene against late blight (Phytophthora infestans) from potato]-like genes. Structural comparison of the NBS domains of all the homologs in Solanaceae revealed that one novel motif, 14, is specific to the Rx-like genes, and also indicated that several other novel motifs are characteristic of the R1-like genes. Our results suggest that Rx-like genes are ancient but conserved. Furthermore, the novel conserved motifs can provide a basis for biochemical structural. function analysis and be used for degenerate primer design for the isolation of Rx-like sequences in other plant species. Comparative mapping study revealed that the position of CapRGC is syntenic to the locations of Rx and its homolog genes in the potato and tomato, but cosegregation analysis showed that CapRGC may not be the R gene against PVX in pepper. Our results confirm previous observations that the specificity of R genes is not conserved, while the structure and function of R genes are conserved. It appears that CapRGC may function as a resistance gene to another pathogen, such as the nematode to which the structure of CapRGC is most similar.

• The Plant Pathology Journal
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• v.25 no.1
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• pp.26-37
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• 2009

Tomato spotted wilt virus (TSWV) was identified from seven plants at two areas, Anyang and Dangjin, in Korea. The isolates of TSWV were seven as TSWV-KATm from tomato, TSWV-KAPo from potato, TSWV-KABal from balsam, TSWV-KACTm from cherry tomato and TSWV-KAIxe from Ixeris dentata at Anyang area, and TSWV-KDSe from sesame and TSWV-KDRP from red pepper at Dangjin area. Pathogenicity of seven TSWV isolates was various on the assay plants, and could not be grouped definitely. Three isolates of TSWV-KAIxe, TSWV-KACTm and TSWV-KABal had relatively narrower host ranges among the seven isolates. Percentage of nucleotide substitution in nucleotide sequences encoding nucleocapsid protein (NCP) was 1.2-1.7% among seven TSWV isolates and TSWV-KP. Korean TSWV isolates were divided into three groups by nucleotide homology or amino acid compositions. From the analysis of nucleotide sequences of Korean TSWV isolates compared with those of TSWV reported from other 5 countries including Japan, the Korean seven isolates of TSWV was grouped with German TSWV (D13926). No Korean TSWV isolates were grouped with those from The Netherlands, Brazil and USA.

• Mycobiology
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• v.43 no.2
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• pp.170-173
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• 2015

Herein, we report the first occurrence of web blight of rosemary caused by Rhizoctonia solani AG-1-IB in Gangneung, Gangwon Province, Korea, in August 2014. The leaf tissues of infected rosemary plants were blighted and white mycelial growth was seen on the stems. The fungus was isolated from diseased leaf tissue and cultured on potato dextrose agar for identification. The young hyphae had acute angular branching near the distal septum of the multinucleate cells and mature hyphal branches formed at an approximately $90^{\circ}$ angle. This is morphologically identical to R. solani AG-1-IB, as per previous reports. rDNA-ITS sequences of the fungus were homologous to those of R. solani AG-1-IB isolates in the GenBank database with a similarity percentage of 99%, thereby confirming the identity of the causative agent of the disease. Pathogenicity of the fungus in rosemary plants was also confirmed by Koch's postulates.

• Mycobiology
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• v.38 no.4
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• pp.286-294
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• 2010

Epicoccum purpurascens stain 5615 AUMC was investigated for its biocontrol activity against root rot disease caused by Pythium irregulare. E. purpurascens greenhouse pathogenicity tests using three leguminous plants indicated that the fungus was nonpathogenic under the test conditions. The germination rate of the three species of legume seeds treated with a E. purpurascens homogenate increased significantly compared with the seeds infested with P. irregulare. No root rot symptoms were observed on seeds treated with E. purpurascens, and seedlings appeared more vigorous when compared with the non-treated control. A significant increase in seedling growth parameters (seedling length and fresh and dry weights) was observed in seedlings treated with E. purpurascens compared to pathogen-treated seedlings. Pre-treating the seeds with the bioagent fungus was more efficient for protecting seeds against the root rot disease caused by P. irregulare than waiting for disease dispersal before intervention. To determine whether E. purpurascens produced known anti-fungal compounds, an acetone extract of the fungus was analyzed by gas chromatography mass spectrometry. The extract revealed a high percentage of the cinnamic acid derivative (trimethylsiloxy) cinnamic acid methyl ester. The E. purpurascens isolate grew more rapidly than the P. irregulare pathogen in a dual culture on potato dextrose agar nutrient medium, although the two fungi grew similarly when cultured separately. This result may indicate antagonism via antibiosis or competition.

• Research in Plant Disease
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• v.8 no.2
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• pp.78-83
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• 2002

Tobacco diseases have not been recorded until 1900s in Korea, where tobacco plants were introduced at early 1700s. Practical researches on the disease have been conducted since mid 1960s. Major ten tobacco diseases were mosaic caused by tobacco mosaic virus·potato virus Y·cucumber mosaic virus, bacterial wilt, hollow stalk, wild fire caused by angular leaf spot strain, black shank, brown spot, powdery mildew and fusarium wilt. But their annual occurrences were varied according to changes of tobacco varieties and their cultivating practices. As no useful chemicals, several biological tactics have been developed to control the viral or bacterial diseases that give significant economic damages on sustainable crop yield, but not practicable to field farming condition yet. Transgenic tobacco plants containing foreign disease resistant genes have been developed by current bio-technology, but not released to farmers yet. Though some disease-resistant tobacco varieties have been developed by the conventional breeding technology and currently used by farmers, their disease controlling efficacy have been diminished by occurrence of the new strain or race. Future research on tobacco diseases has been focused on technical development to produce high quality tobacco with less production cost, which leads Korean tobacco industry to keep its competence against foreign industry and decreasing overall market.

• The Plant Pathology Journal
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• v.29 no.1
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• pp.110-115
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• 2013

Theobroxide, a novel compound isolated from a fungus Lasiodiplodia theobromae, stimulates potato tuber formation and induces flowering of morning glory by initiating the jasmonic acid synthesis pathway. To elucidate the effect of theobroxide on pathogen resistance in plants, Nicotiana benthamiana plants treated with theobroxide were immediately infiltrated with Pseudomonas syringae pv. tabaci. Exogenous application of theobroxide inhibited development of lesion symptoms, and growth of the bacterial cells was significantly retarded. Semiquantitative RT-PCRs using the primers of 18 defense-related genes were performed to investigate the molecular mechanisms of resistance. Among the genes, the theobroxide treatment increased the expression of patho-genesis-related protein 1a (PR1a), pathogenesis-related protein 1b (PR1b), glutathione S-transferase (GST), allen oxide cyclase (AOC), and lipoxyganase (LOX). All these data strongly indicate that theobroxide treatment inhibits disease development by faster induction of defense responses, which can be possible by the induction of defense-related genes including PR1a, PR1b, and GST triggered by the elevated jasmonic acid.