• 식물병과 농업
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• 제5권2호
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• pp.100-104
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• 1999

A total of 65 isolates of Penicillium were isolated from decayed post-harvest fruits of apple pear citrus and grape. The Penicillium species isolated from the apple were idnetified as P. aurantiogriseum and P. expansum those from the pear were P. crustosum and P. expansum and those from the grape were P. aurantiogriseum and P. expansum, From decayed citrus fruits. P. digitatum and P. italicum were isolated. Citrinin and patulin from these species in the YES(yeast extract sucrose) broth were extracted with ethyl acetate and purified by thin-layer chromatography(TLC) and high performance liquid chromatography(HPLC) Among 51 isolates of Penicillium from apple pear and grape 7 isolates produced citrinin 13 isolates produces patulin and 12 isolates produced citrinin and patulin also. All 14 isolates of Penicillium from citrus produced only patulin.

• The Plant Pathology Journal
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• 제34권6호
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• pp.499-505
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• 2018

Huanglongbing (HLB, Citrus greening disease) is one of the most devastating diseases that threaten citrus production worldwide. Although HLB presents systemically, low titer and uneven distribution of these bacteria within infected plants can make reliable detection difficult. It was known loop-mediated isothermal amplification (LAMP) method has the advantages of being highly specific, rapid, efficient, and laborsaving for detection of plant pathogens. We developed a new LAMP method targeting gene contained tandem repeat for more rapid and sensitive detection of Candidatus Liberibacter asiaticus (CLas), putative causal agent of the citrus huanglongbing. This new LAMP method was 10 folds more sensitive than conventional PCR in detecting the HLB pathogen and similar to that of real-time PCR in visual detection assay by adding SYBR Green I to mixture and 1% agarose gel electrophoresis. Positive reactions were achieved in reaction temperature 57, 60 and $62^{\circ}C$ but not $65^{\circ}C$. Although this LAMP method was not more sensitive than real-time PCR, it does not require a thermocycler for amplification or agarose gel electrophoresis for resolution. Thus, we expect that this LAMP method shows strong promise as a reliable, rapid, and cost-effective method of detecting the CLas in citrus and can be applied for rapid diagnosis is needed.

• The Plant Pathology Journal
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• 제40권2호
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• pp.125-138
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• 2024

Citrus yellow vein clearing virus (CYVCV) is a member of the Alphaflexiviridae family that causes yellow vein clearing symptoms on citrus leaves. A total of 118 leaf samples from nine regions of six provinces in Korea were collected from various citrus species in 2020 and 2021. Viral diagnosis using next-generation sequencing and reverse transcription polymerase chain reaction (RT-PCR) identified four viruses: citrus tristeza virus, citrus leaf blotch virus, citrus vein enation virus, and CYVCV. A CYVCV incidence of 9.3% was observed in six host plants, including calamansi, kumquat, Persian lime, and Eureka lemon. Among the citrus infected by CYVCV, only three samples showed a single infection; the other showed a mixed infection with other viruses. Eureka lemon and Persian lime exhibited yellow vein clearing, leaf distortion, and water-soak symptom underside of the leaves, while the other hosts showed only yellowing symptoms on the leaves. The complete genome sequences were obtained from five CYVCV isolates. Comparison of the isolates reported from the different geographical regions and hosts revealed the high sequence identity (95.2% to 98.8%). Phylogenetic analysis indicated that all the five isolates from Korea were clustered into same clade but were not distinctly apart from isolates from China, Pakistan, India, and Türkiye. To develop an efficient diagnosis system for the four viruses, a simultaneous detection method was constructed using multiplex RT-PCR. Sensitivity evaluation, simplex RT-PCR, and stability testing were conducted to verify the multiplex RT-PCR system developed in this study. This information will be useful for developing effective disease management strategies for citrus growers in Korea.

• 식물병연구
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• 제20권3호
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• pp.196-200
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• 2014

본 연구는 파라핀유 첨가가 감귤 과실 표면에서의 만코제브 수화제의 내우성 증대에 대한 효과와 검은점무늬병 방제 효과 증진 여부를 구명하고자 실시하였다. 인공강우를 0시간, 5시간, 10시간 처리한 후 과실표면에 부착되어 있는 만코제브 양을 분석한 결과, 강우 처리 10시간 후에는 만코제브에 파라핀유 0.1%를 혼용 처리한 구에서 과실 표면에 부착된 만코제브 함량이 $7.43{\mu}g/cm^2$으로 가장 많았다. 노지에서 재배하고 있는 온주밀감 나무에 만코제브 0.2%, 만코제브 0.2% + 파라핀유 0.1%, 만코제브 0.2% + 파라핀유 0.25% 그리고 만코제브 0.2% + 전착제를 살포하고 1일, 15일, 25일 후 과실을 채취하여 과실 표면에 부착된 만코제브 양을 조사해 본 결과, 2009년과 2010년 시험 모두 처리 1일, 15일, 25일 후 0.2% 만코제브 수화제에 파라핀유 0.1% 또는 0.25% 혼용하여 살포한 구에서 부착된 만코제브 가장 양이 많았다. 파라핀유를 혼용하여 살포하였을 경우 만코제브 수화제의 감귤 검은점무늬병에 대한 방제 효과 증진 여부를 조사해 본 결과, 2009년의 경우 만코제브 0.2%에 파라핀유 0.1% 또는 0.25%를 각각 첨가하여 5회 살포한 구에서의 발병도가 만코제브 0.2%만 처리한 구 보다 낮았으며 만코제브 0.2%를 6회 살포한 구의 발병도와 비슷하였다. 2010년, 2012년의 경우도 만코제브 0.2%만 처리한 구보다는 만코제브 0.2%에 파라핀유 0.1% 또는 0.25% 첨가한 구에서 발병도가 낮았다. 따라서 감귤 재배 농가에서 검은점무늬병 방제를 위하여 만코제브에 파라핀유 0.1%를 혼용하여 살포하면 훨씬 방제 효과를 높일 수 있을 것으로 생각된다.

• 한국토양비료학회지
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• 제51권1호
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• pp.28-34
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• 2018

Yuzu (Citrus junos) gummosis disease, caused by Phytophthora nicotianae, was first reported in 1997. As known in citrus, Phytophthora is the most fastidious soil-borne pathogen to control. In order to minimize its damage to Citrus spp., integrated pest management (IPM) approach, including fungicide chemicals and resistant cultivars, is necessary. Therefore, in this study we tried to evaluate tolerance of yuzu cultivars and its related species against yuzu Phytophthora. Trifoliate orange was evaluated as a susceptible host to yuzu Phytophthora by both mycelial growth onto extract media and immature fruit inoculation. However, in zoospores spray-inoculation on 2-year-old cuttings tree, trifoliate orange appeared to have a resistant property as showing less than 6% diseased leaf rate. Among yuzu cultivars only 'Namhae No. 1' appeared resistant property against both P. nicotianae and P. citrophthora. The 'Namhae No. 1' showed 5.7% and 10.6% diseased leaf ratio by P. nicotianae and P. citrophthora, respectively. Clearly, in order to reduce damages caused by two yuzu Phytophthora, we suggest that growers may utilize a trifoliate orange as a rootstock and 'Namhae No. 1' as a scion for fruit production.

• The Plant Pathology Journal
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• 제24권3호
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• pp.357-360
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• 2008

Several pathotypes have been recognized in citrus bacterial canker, which causing serious damage in citrus cultivation area. To control the disease, it is important to understand the pathological diversity and reason of difference in virulence of the causal pathogen. We analyzed 124 strains of Xanthomonas causing citrus bacterial canker by southern hybridization with an internal 3.4-kb BamHI fragment from pthA gene. Assuming each band represented an intact gene, each strain of Xanthomonas was estimated to have approximately 1 to 4 copies of pthA gene. X. a. pv. citri A type had more than 3 copies of pthA gene, and the number of pthA gene in X. a. pv. citri $A^*,\;A^w$, and X. a. pv. aurantifolii B, C were different from 1 to 3 according to the strains. When the pthA gene profile was classified into 13 groups according to the number and size of hybridization bands, most of the A types belong to the 3A group, and 4A and 4B type was dominant when they had 4 bands. However, there was no general pattern of difference between the virulence and pthA gene group in this test.

• 식물병연구
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• 제21권3호
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• pp.231-234
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• 2015

Elsinoe fawcettii and E. australis are two currently recognized scab pathogens of citrus. E. fawcettii has at least six pathotypes while E. australis has at least two pathotypes. Colonies of E. fawcettii and E. australis do not sporulate in artificial media including potato dextrose agar (PDA). Whiteside's method has been widely used for preparing conidial inoculum in vitro. This study was carried out to develop efficient method for conidia production from artificial media. We developed a shaking method which included the following steps: 1) Colony grown on PDA was mashed with a steel spatula; 2) Mycelia fragments were cultured in 50 ml sterilized rain water in a rotary shaker-incubator (180 rpm) at $25^{\circ}C$ for 24 h: 3) The conidia suspension was filtered through two layers of cheesecloth. Average conidia production of all isolates tested using this shaking method was approximately 13.1 times higher than that from Whiteside's method in this study.

• The Plant Pathology Journal
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• 제39권4호
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• pp.351-360
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• 2023

Citrus melanose, caused by Diaporthe citri, has been one of the serious diseases, and chemical fungicides were used for protection in many citrus orchards of Jeju Island. Establishing a disinfectant resistance management system and reducing pesticide usage would be important for contributing to safe agricultural production. In this study, monitoring of chemical resistance was performed with 40 representative D. citri isolates from many citrus orchards in Jeju Island. Four different fungicides, kresoxim-methyl, benomyl, fluazinam, and prochloraz manganese, with seven different concentrations were tested in vitro by growing the mycelium of the fungal isolates on the artificial medium potato dextrose agar. Among the 40 fungal isolates, 12 isolates were investigated as resistant to kresoxim-methyl which could not inhibit the mycelium growth to more than 50%. Especially isolate NEL21-2 was also resistant against benomyl, whose hyphae grew well even on the highest chemical concentration. However, any chemical resistance of fungal isolates was found against neither fluazinam nor prochloraz manganese. On the other hand, in vivo bio-testing of some resistant isolates was performed against both kresoxim-methyl and benomyl on young citrus leaves. Typical melanose symptoms developed on the citrus leaves pre-treated with both agrochemicals after inoculation with the resistant isolates. However, no or less symptoms were observed when the susceptible isolates were inoculated. Based on these results, it was suggested that some resistant isolates of D. citri occurred against both systemic fungicides, which may be valuable to build a strategy for protecting citrus disease.

• Nutrition Research and Practice
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• 제12권2호
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• pp.129-134
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• 2018

BACKGROUND/OBJECTIVES: Although several recent studies have reported the anti-cancer effects of extracts or components of Citrus unshiu peel, which has been used for various purposes in traditional medicine, the molecular mechanisms for their effects remain unclear. In the present study, the anti-cancer activity of a water-soluble extract of C. unshiu peel (WECU) in MDA-MB-231 human breast carcinoma cells at the level of apoptosis induction was investigated. MATERIALS/METHODS: Cytotoxicity was evaluated using the MTT assay. Apoptosis was detected using DAPI staining and flow cytometry analyses. Mitochondrial membrane potential, reactive oxygen species (ROS) assay, caspase activity and Western blotting were used to confirm the basis of apoptosis. RESULTS: The results indicated that WECU-induced apoptosis was related to the activation of caspase-8, and -9, representative initiator caspases of extrinsic and intrinsic apoptosis pathways, respectively, and caspase-3 accompanied by proteolytic degradation of poly(ADP-ribose) polymerase and down-regulation of the inhibitors of apoptosis protein family members. WECU also increased the pro-apoptotic BAX to anti-apoptotic BCL-2 ratio, loss of mitochondrial membrane potential and cytochrome c release from mitochondria to cytoplasm. Furthermore, WECU provoked the generation of ROS, but the reduction of cell viability and induction of apoptosis by WECU were prevented when ROS production was blocked by antioxidant N-acetyl cysteine. CONCLUSIONS: These results suggest that WECU suppressed proliferation of MDA-MB-231 cells by activating extrinsic and intrinsic apoptosis pathways in a ROS-dependent manner.

• 한국유기농업학회지
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• 제28권2호
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• pp.223-233
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• 2020

본 연구에서는 친환경 농가에서 사용되고 있는 바이오 황(Bio-S, bio-sulfur)을 이용하여 감귤 더덩이병(Citrus scab)에 대한 발병 억제 효과를 알아보고자 수행되었다. 바이오 황이 감귤 더뎅이병의 발아관 생장 억제 효과는 감귤 더뎅이병균을 PDB와 Agar 배지에서 배양하여 발아관을 관찰한 결과 접종 40시간과 88시간 모두 바이오 황 500배, 1,000배, 2,000배 처리구에서 발아관 형성이 억제되었으며, 4,000배 이상 희석배수가 높아질수록 발아관은 형성되었으나 무처리구에 비해 생장이 억제되었다. 포장에서 감귤 봄순 잎에 대한 더뎅이병의 발병 억제 효과는 무처리구 이병율은 40.3%였으며, 화학농약인 Imibenconazole 수화제 이병율이 5.3%을 보였으며, 친환경 농업에 사용하는 석회보르도액 2-4식과 6-6식은 모두 10.3%, 바이오 황 500배 12.3%, 석회유황합제 15.3%로 비슷한 경향을 나타냈으며, 반면 바이오 황 1,000배에서는 24.0%로 비교적 높은 이병율을 보였다. 감귤 과실에 대한 시험결과 무처리구 이병율은 79.3%였으며, Imibenconazole 수화제 이병율은 4.0%을 보였으며, 석회보르도액 2-4식 33.8%, 6-6식 42.0%, 바이오 황 500배 43.3%, 석회유황합제 44.8%로 비슷한 효과를 나타냈으며, 반면 바이오 황 1,000배에서는 78.0%로 비교적 높은 이병율을 보였다. 따라서 감귤 더뎅이병은 봄순이 전개되는 5월부터 감귤의 잎에 발생하기 때문에 봄순이 전개되기 전인 4월 중하순부터 예방방제를 시작하여 예찰을 통해 방제하면 높은 방제율과 노동력 및 영농비용 등을 절감할 수 있을 것으로 생각된다.