• 농업생명과학연구
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• 제43권6호
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• pp.105-109
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• 2009

경산 묘목단지는 대단위 과수종묘를 생산하고 있어 경쟁력 강화를 위하여 무독묘 보증 생산이 요구되고 있다. 특히 생산규모가 큰 사과종묘에 대한 빠르고 정확한 바이러스 진단이 시급하다. 본 연구에서는 사과바이러스 진단을 위하여 다량의 시료를 동시 분쇄할 수 있는 bead beater를 이용하였으며 분쇄 bead는 저가의 산업용 glass bead (0.4 mm 직경)를 일회용으로 채택하였다. RNA추출을 위하여서는 guanidine thiocyanate 용액이 Trizol 용액보다 효과적인 것으로 나타났으며 silica membrane tube의 이용으로 RNA추출 간편성을 높일 수 있었다. 사과바이러스는 RT-PCR에 의하여 검증하였다.

• The Plant Pathology Journal
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• 제35권5호
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• pp.530-537
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• 2019

Fuji, a major apple cultivar in Korea, is susceptible to white rot. Apple white rot disease appears on the stem and fruit; the development of which deteriorates fruit quality, resulting in decreases in farmers' income. Thus, it is necessary to characterize molecular markers related to apple white rot resistance. In this study, we screened for differentially expressed genes between uninfected apple fruits and those infected with Botryosphaeria dothidea, the fungal pathogen that causes white rot. Antimicrobial tests suggest that a gene expression involved in the synthesis of the substance inhibiting the growth of B. dothidea in apples was induced by pathogen infection. We identified seven transcripts induced by the infection. The seven transcripts were homologous to genes encoding a flavonoid glucosyltransferase, a metallothionein-like protein, a senescence-induced protein, a chitinase, a wound-induced protein, and proteins of unknown function. These genes have functions related to responses to environmental stresses, including pathogen infections. Our results can be useful for the development of molecular markers for early detection of the disease or for use in breeding white rotresistant cultivars.

• Journal of Biosystems Engineering
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• 제22권2호
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• pp.217-226
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• 1997

This study was to develop a machine vision system to detect and to discriminate 5 kinds of apple surface defectbruise, decay. fleck, worm hole and scar. To detect the defects from an image of apple, thresholding technique was applied to images on various frames (R, G, B, H, S and I) of the color machine vision and an image of near infrared (NIR). To discriminate the detected region of defect, various features of the 5 kind defect regions were extracted from the 4 kinds of images selected above. The features were size of area, roundness, axes length ratio, mean and valiance of pixel values, standard deviation of real part of amplitude spectrum in frequency domain obtained by Fourier transform of pixel data and mean and standard deviation of power spectrum obtained by the same transform of pixel data. Routines to discriminate the defects from the features of image were developed and tested to prove their validity. The test resulted that I-frame and NIR images were the most desirable. Accuracies of the two images to discriminate the defects were noted as 76% and 77%, respectively.

• 한국환경농학회지
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• 제23권4호
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• pp.245-250
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• 2004

An analytical method was developed to determine monocrotophos residues in apple, citrus, and soil using high-performance liquid chromatography (HPLC) with ultraviolet absorption detection. Monocrotophos was extracted with acetone from apple, citrus and moist soil samples. The extract was concentrated, added with saline water, and subjected to n-hexane washing to remove nonpolar co-extractives. Dichloromethane partition was then followed to recover monocrotophos from the aqueous phase. Silica gel column chromatography was employed to further purify the extract prior to HPLC determination. Reverse-phase HPLC using an oct-adecylsilyl column was successfully applied to separate and quantitate the monocrotophos residue in sample extracts at the wavelength of 230 nm. Overall recoveries of monocrotophos from fortified samples averaged $95.3{\pm}2.1%$ (n=6), $970{\pm}0.7%$ (n=6), and $92.8{\pm}4.3%$ (n=12) for apple, citrus, and soil, respectively. The proposed method was quite reproducible and sensitive enough to replace the troublesome gas-liquid chromatographic analysis for monocrotophos residues.

• 분석과학
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• 제9권2호
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• pp.123-133
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• 1996

기체 크로마토그래피법을 이용하여 과수 재배용 살균제인 difenoconazole의 분석을 위한 최적 조건을 구하고, 사과와 토양 중에서의 잔류성을 조사하였다. 사과사료는 5% NaCl과 n-hexane액으로 분리, 농축하여 florisil column상에서 acetone과 n-hexane 혼합액으로 정제하여 GLC(ECD)로 분석하였다. 0.20과 1.0ppm의 표준물 첨가실험결과 평균회수율은 86.0~92.0% 였고, 검출한계는 0.01ppm 이었다. 사과에 대한 안정 사용기간은 수확 15일 전 3회 사용이 적당한 것으로 나타났으며, 이 경우 difenoconazole의 잔류량은 0.037ppm에서 0.044ppm 이었다. 토양시료를 methanol과 ammonium hydroxide 의 혼합액으로 추출하여 여과한 후 포화 NaCl 용액과 dichloromethane층으로 분배하였다. 유기층을 농축하여 toluene 용매로 재용해하였고, Sep-Pak column으로 정제한 후 GLC(FID)로 분석하였다. 0.10, 0.50과 1.0ppm 표준물 첨가실험 결과 평균 회수율은 101.2~103.7% 였고, 검출한계는 0.025ppm 이었다.

• The Plant Pathology Journal
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• 제30권2호
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• pp.195-199
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• 2014

Apple stem pitting virus (ASPV), of the Foveavirus genus in the family Betaflexiviridae, is one of the most common viruses of apple and pear trees. To examine variability of the coat protein (CP) gene from ASPV, eight isolates originating from 251 apple trees, which were collected from 22 apple orchards located in intensive apple growing areas of the North Gyeongsang and North Jeolla Provinces in Korea, were sequenced and compared. The nucleotide sequence identity of the CP gene of eight ASPV isolates ranged from 77.0 to 97.0%, while the amino acid sequence identity ranged from 87.7 to 98.5%. The N-terminal region of the viral CP gene was highly variable, whereas the C-terminal region was conserved. Genetic algorithm recombination detection (GARD) and single breakpoint recombination (SBP) analyses identified base substitutions between eight ASPV isolates at positions 54 and 57 and position 771, respectively. GABranch analysis was used to determine whether the eight isolates evolved due to positive selection. All values in the GABranch analysis showed a ratio of substitution rates at non-synonymous and synonymous sites (dNS/dS) below 1, suggestive of strong negative selection forces during ASPV CP history. Although negative selection dominated CP evolution in the eight ASPV isolates, SLAC and FEL tests identified four possible positive selection sites at codons 10, 22, 102, and 158. This is the first study of the ASPV genome in Korea.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 동계 학술대회 논문집
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• pp.445-450
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• 2000

• The Plant Pathology Journal
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• 제22권1호
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• pp.63-67
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• 2006

Apple scar skin, one of the most destructive diseases affecting apple, is caused by Apple scar skin viroid (ASSV d). Fruit dappling appeared on several cultivars in Korea and has been distributed to major cultivated areas since 2001. ASSVd was identified from infected fruits by using nucleic acid sequence-based amplification with electrochemiluminescence (NASBA-ECL). NASBA-ECL method was faster and hundredfold more sensitive than reverse transcription-polymerase chain reaction (RT-PCR) for ASSVd detection in apple leaves/ stems. ASSVd was rapidly transmitted to the entire tree in the second year after artificial inoculation. The ASSVd could be transmitted efficiently by using contaminated pruning scissors to both lignified stems (60 to $70\%$) and green shoots (20 to $40\%$) of apple tree and young plants. Dipping of contaminated scissors in $2\%$ sodium hypochlorite solution effectively prevented viroid transmission. In the ASSV d-infected fruits, the viroid was easily detected from fruit skin, seed coat, and embryo. Moreover, embryo and endosperm separately excised from the ASSVd-infected seeds were ASSVd positive in NASBA-ECL assay. Seedlings germinated from ASSVd-positive seeds showed $7.7\%$ infection rate., which indicated that ASSVd is seed-borne.

• The Plant Pathology Journal
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• 제32권5호
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• pp.441-451
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• 2016

Deep sequencing has generated 52 contigs derived from five viruses; Apple chlorotic leaf spot virus (ACLSV), Apple stem grooving virus (ASGV), Apple stem pitting virus (ASPV), Apple green crinkle associated virus (AGCaV), and Apricot latent virus (ApLV) were identified from eight apple samples showing small leaves and/or growth retardation. Nucleotide (nt) sequence identity of the assembled contigs was from 68% to 99% compared to the reference sequences of the five respective viral genomes. Sequences of ASPV and ASGV were the most abundantly represented by the 52 contigs assembled. The presence of the five viruses in the samples was confirmed by RT-PCR using specific primers based on the sequences of each assembled contig. All five viruses were detected in three of the samples, whereas all samples had mixed infections with at least two viruses. The most frequently detected virus was ASPV, followed by ASGV, ApLV, ACLSV, and AGCaV which were withal found in mixed infections in the tested samples. AGCaV was identified in assembled contigs ID 1012480 and 93549, which showed 82% and 78% nt sequence identity with ORF1 of AGCaV isolate Aurora-1. ApLV was identified in three assembled contigs, ID 65587, 1802365, and 116777, which showed 77%, 78%, and 76% nt sequence identity respectively with ORF1 of ApLV isolate LA2. Deep sequencing assay was shown to be a valuable and powerful tool for detection and identification of known and unknown virome in infected apple trees, here identifying ApLV and AGCaV in commercial orchards in Korea for the first time.

• The Plant Pathology Journal
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• 제39권1호
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• pp.88-107
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• 2023

In the present investigation, bacterial isolates from infected apple trees causing apple canker during winter were studied in the northern Gyeongbuk Province, Korea. The pathogen was identified as Pseudomonas syringae pv. syringae (Pss) through various physiological and biochemical characterization assays such as BIOLOG, gas chromatography of fatty acid methyl esters, and 16S rRNA. Bioassays for the production of phytotoxins were positive for syringopeptin and syringomycin against Bacillus megaterium and Geotrichum candidum, respectively. The polymerase chain reaction (PCR) method enabled the detection of toxin-producing genes, syrB1, and sypB in Pss. The differentiation of strains was performed using LOPAT and GATTa tests. Pss further exhibited ice nucleation activity (INA) at a temperature of -0.7℃, indicating an INA⁺ bacterium. The ice-nucleating temperature was -4.7℃ for a non-treated control (sterilized distilled water), whereas it was -9.6℃ for an INA^- bacterium Escherichia coli TOP10. These methods detected pathogenic strains from apple orchards. Pss might exist in an apple tree during ice injury, and it secretes a toxin that makes leaves yellow and cause canker symptoms. Until now, Korea has not developed antibiotics targeting Pss. Therefore, it is necessary to develop effective disease control to combat Pss in apple orchards. Pathogenicity test on apple leaves and stems showed canker symptoms. The pathogenic bacterium was re-isolated from symptomatic plant tissue and confirmed as original isolates by 16S rRNA. Repetitive element sequence-based PCR and enterobacterial repetitive intergenic consensus PCR primers revealed different genetic profiles within P. syringae pathovars. High antibiotic susceptibility results showed the misreading of mRNA caused by streptomycin and oxytetracycline.