• 식물병연구
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• 제19권4호
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• pp.300-307
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• 2013

This study was conducted to determine the occurrence of leaf rot and leaf ring spot, caused by Rhizoctonia solani in Chinese cabbage under seedling nursery and cultivation greenhouses. Symptoms of leaf rot and leaf ring spot were found in three Chinese cabbage cultivars, Brassica campestris subsp. pekinensis, 'Ryeokgwang', 'Daetong', and 'CR mat'. In Hwacheon, the disease incidence was 73.8% in the seedling stage of the Chinese cabbage. In Icheon, the symptoms were observed on the upper leaves of the Chinese cabbage cultivar, 'Norangmini' with 20.5% of disease incidence. The symptoms appeared as primary lesions consisting of small, circular necrotic ring spots with gray color, 1.4-3.0 mm in diameter, accompanied by secondary rot lesions with large irregular borders of leaves. The color of mycelial mat of 20 isolates was dark brown and light brown. The average hyphal diameter of all the isolates was within 5.01-11.12 ${\mu}m$. Among the 20 strains isolated from Chinese cabbage, 16 isolates and four isolates anastomosed with the AG-1 (IB) and AG-1 (IC), respectively. Twenty isolates tested were only virulent on foliage parts of Chinese cabbage leaves but were avirulent on stem parts of the plants. Based on the mycological characteristics and pathogenicity test on host plants, the fungus was identified as Rhizoctonia solani.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.242-242
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• 2017

A potato cultivar, Haryeong, was released for table stock in 2005 and has been supplied to farmers since 2010. Black dot has been known as a disease causing tuber blemishes in the cultivar, which is primarily an issue in storage. To investigate the effect of curing periods on disease occurrence, four periods (1, 3, 6 and 9 weeks) of curing were applied on Haryeong tubers harvested from the highlands (800 m a.s.l) in September. Tubers were stored at $2-3^{\circ}C$ and 80-90% RH for 6-7 months and were visually checked for disease occurrence. Tuber infection was characterized by barely visible small black spots on tubers and dark sooty lesions in stolon end of tubers. Another symptoms were observed on the upper surface of tubers which showed irregular, small to large, and depressed areas of brown to blackish skin with necrotic lesions inside. Results showed decrease in black dot depending on the curing period that ranges 18-48, 3-35, 0-14 and 0-3% at 1, 3, 6 and 9 weeks curing, respectively. During the storage, however, percentage weight loss of tubers and percentage of tubers with sprouts increased slightly with increasing the curing period from 1-3 to 6-9 weeks.

• 식물병연구
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• 제24권1호
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• pp.81-85
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• 2018

2016년 충북 충주에서 모자이크 병징을 보이는 초석잠을 채집하였다. 담배와 명아주에 즙액접종을 실시한 결과 담배에서 접종엽에 괴사반점이 나타나고 명아주 2종에서 상엽에 퇴록반점을 동반한 모자이크 병징이 관찰되었다. 기주반응과 결과를 통해 여러 바이러스의 복합감염을 추정할 수 있었고, 추정되는 바이러스의 확인을 위해 속특이 및 종특이 프라이머를 이용하여 RT-PCR을 수행하여 3종의 바이러스(AMV, CMV, TMV)를 검정하였다. 본 연구는 국내 초석잠에서 3종의 바이러스 감염을 확인하였고 CMV의 감염에 대한 첫 보고이다.

• 대한수의학회지
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• 제34권4호
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• pp.787-799
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• 1994

To elucidate morphologic lesion of porcine exudative epidermitis which is occurred sporadically in Korea, Staphylococcus hyicus subsp. hyicus isolated from the naturally affected pigs was inoculated to suckling pigs. The infected piglets were observed grossly and histopathologically. Although affected piglets were taking acute, subacute, or chronic course, some piglets suffered from chronic disease showed poor prognosis and marked growth depression. Affected peglets had erythematous skin on the face, ear, and abdomen and these localized lesions appear as brownish spots of exudative epidermitis and fromed crust in the early stage. But, after this stage, the skin were covered by viscous greasy exudate and formed blackish brown crust and appeared fissures and hypertrophy. Grossly, there has been hemorrhage with the removal of crust-like materials of epidermis and edematous subcutis. The superficial lymph nodes were edematous and swollen or congested and hemorrhagic. Some piglets had swollen ureters, cysts in the renal cortex, or polyarthritis. A few cases had mild edematous swelling of kidney, intestinal catarrh and congestion of brain. Microscopically, skin lesions had detachment of keralinized layer and parakeratosis of epidermis, hydropic degeneration of epidermal cell, and retrogressive degeneration of hair root sheath. Dermis had edema, and infiltration of neutrophils and mononuclear cells. As the disease was proceeded, there was marked perivasculitis with lots of mononuclear inflammatory cells. More chronic lesions formed granuloma-like bodies(nodules) due to more mononuclear, perivascular inflammatory cell infiltration and proliferation of fibroblast. Lots of plasma cells and eosinophils were also present in dermis. Epidermis was hyperplastic by proliferation of basal cells stratum germinativum and epidermal pegs often extended into the dermis. In secondary infection, lots of neutrophils could be seen in epidermis and derms. Kidney had neutrophilic infiltration, necrotic and cystic glomeruli, and dilation of renal tubules and ureters. Purulent arthritis was sometimes observed in joints. Three days old mice administrated Staphylococcus hyicus subsp hyicus subcutaneously before had focal congestion and hemorrhage, necrosis, and subcutaneous edema of the skin. This observation was also seen in the study of mice administrated exfoliatin toxin of Staphylococcus which evoked human staphylococcal scalded skin syndrome.

• 대한수의학회지
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• 제40권1호
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• pp.101-109
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• 2000

Duck viral hepatitis is an acute, highly infectious viral disease of young dacklings aged from two days to three weeks. The significant lesion associated with the disease was enlarged liver including necrotic foci and numerous hemorrhagic spots. We have isolated five strains of duck hepatitis virus (DHV) from field cases showing about 20% mortality with a sign of opisthotonos. When a-day-old ducklings were intramuscularly inoculated with one of the isolates, 92% of the birds were died within 5 days. We attempted to develop an attenuated strain of duck hepatitis virus (DHV) using one of the isolates by serial chicken embryo passages. The propagation of DHV in chicken embryos was carried 140 passages. The virus titer increased gradually from the $21^{st}$ through the $50^{th}$ passage, but there was no significant increase of virus titer in subsequent passages after then. Through the serial passages, the virulence of the virus for chicken embryos was gradually increased but decreased for ducklings. The pathogenicity of the virus for ducklings was preserved up to the $21^{st}$ passage but disappeared at the $50^{th}$passage. An attenuated Korean isolate which was passaged 140 times in chicken embryos gave good protection in ducklings against both challenge infection to a Korean virulent strain and to a DHV-DRL strain, a type 1 reference strain of DHV, which indicated that the Korean isolates could be classified as DHV type 1. And the above results suggest that an attenuated Korean isolate can be used for developing a live DHV vaccine.

• Journal of Microbiology and Biotechnology
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• 제16권9호
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• pp.1392-1398
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• 2006

We investigated a possible coordination between the biosyntheses of two polyketides in the cereal head blight fungus Gibberella zeae, zearalenone (ZEA) and aurofusarin (AUR), which are catalyzed by the polyketide synthases (PKS) PKS4/PKS13 and PKS12, respectively. To determine if the production of one polyketide influences that of the other, we used four different transgenic strains of G zeae; three were deficient for either ZEA or AUR or both, and one was an AUR-overproducing strain. The mycelia of both the wild-type and ${\Delta}PKS4$ strain deficient for ZEA produced AUR normally, whereas the mycelia of both the ${\Delta}PKS12$ and ${\Delta}PKS4::{\Delta}PKS12$ strain showed no AUR accumulation. All the examined deletion strains caused necrotic spots on the surface of com kernels and were found to produce the nonpolyketide mycotoxins trichothecenes to the same amount as the wild-type strain. In contrast, the AUR-deficient ${\Delta}PKS12$ strains produced greater quantities of ZEA and its derivatives than the wild-type progenitor on both a rice substrate and a liquid medium; the AUR-overproducing strain did not produce ZEA on either medium. Furthermore, the expression of both PKS4 and PKS13 was induced earlier in the ${\Delta}PKS12$ strains than in the wild-type strain, and there was no difference in the transcription of PKS12 between the two strains. Therefore, these results indicate that the ZEA biosynthetic pathway is negatively regulated by the accumulation of another polyketide (AUR) in G zeae.

• The Plant Pathology Journal
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• 제31권4호
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• pp.371-378
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• 2015

Surveys of yellowing viruses in plastic tunnels and in open field crops of melon (Cucumis melo cultivar catalupo), oriental melon (C. melo cultivar oriental melon), and cucumber (C. sativus) were carried out in two melon-growing areas in 2014, Korea. Severe yellowing symptoms on older leaves of melon and chlorotic spots on younger leaves of melon were observed in the plastic tunnels. The symptoms were widespread and included initial chlorotic lesions followed by yellowing of whole leaves and thickening of older leaves. RT-PCR analysis using total RNA extracted from diseased leaves did not show any synthesized products for four cucurbit-infecting viruses; Beet pseudo-yellows virus, Cucumber mosaic virus, Cucurbit yellows stunting disorder virus, and Melon necrotic spot virus. Virus identification using RT-PCR showed Cucurbit aphid-borne yellows Virus (CABYV) was largely distributed in melon, oriental melon and cucumber. This result was verified by aphid (Aphis gossypii) transmission of CABYV. The complete coat protein (CP) gene amplified from melon was cloned and sequenced. The CP gene nucleotide and the deduced amino acid sequence comparisons as well as phylogenetic tree analysis of CABYV CPs showed that the CABYV isolates were undivided into subgroups. Although the low incidence of CABYV in infections to cucurbit crops in this survey, CABYV may become an important treat for cucurbit crops in many different regions in Korea, suggesting that CABYV should be taken into account in disease control of cucurbit crops in Korea.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2020년도 추계국제학술대회
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• pp.63-63
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• 2020

Rice stripe virus (RSV) disease is one of the major constraints in rice production, transmitted by the small brown planthopper (SBPH; Laodelphax striatellus). Upon RSV infection, plants develop typical symptoms, which include chlorosis and weakness of newly emerged leaves, white and yellow spots, stripe on leaves, and necrotic and wilting leaves, resulting in plant growth inhibition, oxidative damage that may culminate in programmed cell death (PCD) and plant death in severe epidemics. Although RSV-resistant quantitative trait loci (QTLs), Stv-a, Stv-b, and Stv-bi, were mapped using various resistant varieties, one RSV-resistant gene, OsSOT1, has been identified so far. In this study, we used the rice cultivar Zenith, known to carry Stv-b, to investigate novel RSV-genes through fine mapping. Therefore, we crossed Zenith (Donor parent, RSV resistant) with Ilpum (Recurrent parent, RSV susceptible) to fine-map using a BC₂F₂ population of 2100 plants. Chromosome segment introgression lines that were heterozygous at a different region were selected, two types of heterozygous lines showed an heterozygous genotype between Sid2 and Sid75 to Indel9 and RM6680. Interestingly, we identified qSTV11^Z region harboring Stv-b, covering about 171-kb region between the InDel markers Sid75 and Indel8. The localization of qSTV11^Z provides useful information that could be used for marker-assisted selection and determination of genetic resources in rice breeding.

• 식물병연구
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• 제30권2호
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• pp.157-164
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• 2024

Jack bean (Canavalia ensiformis) is one of healthy products for fermented or functional food in Korea and is widely distributed and cultivated worldwide. During August 2022, Jack bean plants showing symptoms of yellow flecks, chlorosis, necrotic spots and mosaic were observed in Jangheung-gun, South Korea. By transmission electron microscopy, flexuous filamentous virus particles of approximately 750×13 nm in size were observed in the symptomatic leaf samples. The infection of a Korean isolate of clover yellow vein virus (ClYVV-Ce-JH) was confirmed using double antibody sandwich enzyme-linked sorbent assay, reverse transcription polymerase chain reaction and high-throughput sequencing. The complete genome sequence of ClYVV-Ce-JH consists of 9,549 nucleotides (nt) excluding the poly (A) tail and encodes 3,072 amino acids (aa), with an AUG start and UAG stop codon, containing one open reading frame that is typical of a potyvirus polyprotein. The polyprotein of ClYVV-Ce-JH was divided into ten proteins and each protein's cleavage sites were determined. The coat protein (CP) and polyprotein of ClYVV-Ce-JH were compared at the nt and aa levels with those of the previously reported 14 ClYVV isolates. ClYVV-Ce-JH shared 92.62% to 99.63% and 93.39% to 98.05% at the CP and polyprotein homology. To our knowledge, this is the first report of a Korean isolate of ClYVV from Jack bean plants and the complete genome sequence of a ClYVV Jack bean isolate in the world.

• 식물병연구
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• 제18권3호
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• pp.250-254
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• 2012

2011년 7월 남양주에서 코스모스에 흰깜부기병이 크게 발생함을 발견하였다. 중부지방의 코스모스 집단식재지 9곳을 답사한 결과, 모두 50% 이상의 발병률을 보였다. 초기 병징은 잎에 담녹색이거나 퇴색부위가 생기고, 이어서 병반에는 흰 곰팡이가 서릿발처럼 밀생하였다. 각 병반이 융합되고 괴사되면서 식물체의 관상적 가치는 크게 훼손되었다. 분생포자다발은 잎 뒷면에 생기나 발병 후기에는 앞면에서도 관찰되었다. 분생포자경은 10-40개 정도가 다소 빽빽한 다발을 형성하며, 무색이며, 대부분 기름방울을 가지며, 길이 $20-45{\mu}m$에 폭 $2-4{\mu}m$이며, 꼭대기는 대체로 둥근 편이며, 분생포자흔은 뚜렷하지 않았다. 분생포자는 단생하며, 소시지 모양이며, 무색이며, 단세포이며, 대부분 기름방울을 가지며, 위쪽은 둥글며, 아래쪽은 둥글거나 절단형이며, 길이 $17-24{\mu}m$에 폭 $3.5-5{\mu}m$이며, 배꼽은 뚜렷하지 않았다. 포자퇴는 둥글거나 길쭉하며, 초기에는 희끗하게 보이나 후기에는 갈색의 점처럼 보였다. 겨울포자는 잎 조직 속에 박혀있으며, 근원형이거나 타원형이며, 무색에 가깝거나 옅은 황갈색이며, 길이 $12.5-20{\mu}m$에 폭 $10-15{\mu}m$였다. 이러한 균학적 특징은 코스모스 흰깜부기병균 E. cosmi V$\acute{a}$nky, Horita & Jage와 일치하였다. 이는 한국에서 E. cosmi에 의한 코스모스 흰깜부기병의 최초 보고이다.