• 식물병연구
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• 제29권4호
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• pp.433-439
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• 2023

당근 세균잎마름병은 세계적으로 가장 중요한 병에 속한다. 지난 10년 전 국내에서 처음 발견됨으로써 당근 생산에 큰 위협이 되는 병으로 간주되었다. 원인균으로 Xathomonas hortorum pv. carotae (Xhc)이며 본 연구는 제주도 당근재배지 토양에서 이 병원균을 분리 동정하고자 수행하였다. 분리한 세균 중 인공배지에서 균총의 형태가 당근 세균잎마름병균과 유사한 세균균총을 분리하여 선발하였다. 또한 이들 선발된 세균들을 대상으로 DNA 염기 서열과 NCBI 자료를 통해 몇몇 분리 세균이 Xhc으로 동정되었다. 게다가 이들 세균을 당근 잎에 접종하였더니 당근 세균잎마름병의 전형적인 병징이 나타났다. 본 연구 결과는 제주도 토양내 Xhc의 존재 가능성을 시사하고 앞으로의 당근 세균잎마름병 방제 수단을 강구하는 데 매우 필요한 자료로서 가치가 있다고 본다.

• 한국미생물·생명공학회지
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• 제46권4호
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• pp.346-359
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• 2018

Xanthomonas oryzae, a bacterial pathogen causing leaf blight disease (BLB) in rice, can cause widespread disease and has caused epidemics globally, resulting in severe crop losses of 50% in Asia. The pathogen is seed-borne and is transmitted through seeds. Thus, control of BLB requires the elimination of the pathogen from seeds. Concern about environment-friendly organic production has spurred improvements in a variety of biological disease control methods, including the use of bacteriophages, against bacterial plant pathogens. The present study explored the potential of bacteriophages isolated from diseased plant leaves and soil samples in killing the bacterial pathogen in rice seeds. Eight different phages were isolated and evaluated for their bacteriolytic activity against different pathogenic X. oryzae strains. Of these, a phage designated ${\varphi}XOF4$ killed all the pathogenic X. oryzae strains and showed the broadest host range. Transmission electron microscopy of ${\varphi}XOF4$ revealed it to be a tailed phage with an icosahedral head. The virus was assigned to the family Siphoviridae, order Caudovirales. Seedlings raised from the seeds treated with $1{\times}10^8pfu/ml$ of ${\varphi}XOF4$ phage displayed reduced incidence of BLB disease and complete bacterial growth inhibition. The findings indicate the potential of the ${\varphi}XOF4$ phage as a potential biological control agent against BLB disease in rice.

• The Plant Pathology Journal
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• 제16권6호
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• pp.331-334
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• 2000

Alternaria helianthi and two unreported species of Alternaria in Korea were isolated from lesions of Alternaria leaf spot disease of sunflower. The unrecorded species of Alternaria were identified as A. helianthinficients and A. protenta based on the morphological characteristics of conidiophores and conidia. A. helianthi was the dominant species, although all the three species were associated with the disease. A. helianthi, A. helianthinficiens and A. protenta produced similar symptoms on detached sunflower leaves. This is the first report of A. helianthinficiens and A. protenta pathogenic on sunflower in Korea.

• 식물병연구
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• 제16권1호
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• pp.94-96
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• 2010

In May of 2004 through 2007, Leptosphaerulina leaf blight caused by Leptosphaerulina trifolii occurred on Kentucky bluegrass (Poa pratensis) at golf courses in Gangwon Province, Korea. Symptoms on the turfgrass caused by L. trifolii were leaf blights, dying from the leaf tip downwards to the crown, which appeared patches in the field because of local pockets of severely infected (blighted) grass. Perithecia were produced on old or weak leaves, including club-shaped asci, each of which contained 8 pale brown muriform ascospores with cross and longitudinal septa. Ascospores of the fungus isolated from the diseased leaf tissue and cultured on potato-dextrose agar (PDA) were muriform multicellular (composed of 3-6 cells) and $23.4-40.5{\times}7.8-15.6{\mu}m$ in size with 3-4 transverse and 0-3 longitudinal septa, which were morphologically identical to L. trifolii reported previously. DNA sequences of ribosomal RNA gene (internal transcribed spacer) of the fungus were homologous with similarity of 99% to those of L. trifolii isolates in GenBank database, confirming the identity of the causal agent of the disease. Pathogenicity of the fungus was also confirmed on the creeping bentgrass by Koch's postulates. This is first report of Leptosphaerulina leaf blight on turfgrass caused by L. trifolii in Korea.

• The Plant Pathology Journal
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• 제28권2호
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• pp.164-171
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• 2012

Rice blast disease caused by Magnaporthe grisea (Hebert) Barr [teleomorph] is one of the most devastating diseases in rice plantation areas. Silicon is considered as a useful element for a large variety of plants. Rice variety MR219 was grown in the glasshouse to investigate the function of silicon in conferring resistance against blast. Silica gel was applied to soil while sodium silicate was used as foliar spray at the rates of 0, 60, 120, 180 g/5 kg soil and 0, 1, 2, 3 ml/l respectively. The treatments were arranged in a completely randomized design. Disease severity and silicon content of leaves were compared between the non-amended controls and rice plants receiving the different rates and sources of silicon. Silicon at all rates of application significantly (${\alpha}$ = 0.05) reduced the severity of disease with highest reduction (75%) recorded in treatments receiving 120 g of silica gel. SEM/EDX observations demonstrated a significant difference in weight concentration of silicon in silica cells on the leaf epidermis between silicon treated (25.79%) and non treated plants (7.87%) indicating that Si-fertilization resulted in higher deposition of Si in silica cells in comparison with non-treated plants. Application of silicon also led to a significant increase in Si contents of leaves. Contrast procedures indicated higher efficiency of silica gel in comparison to sodium silicate in almost all parameters assessed. The results suggest that mitigated levels of disease were associated with silicification and fortification of leaf epidermal cells through silicon fertilization.

• 식물병연구
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• 제14권1호
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• pp.21-25
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• 2008

본 연구는 잎도열병에 대한 합리적 약제방제수준을 설정하기 위하여 수행하였다. 발병은 온실에서 도열병균을 접종하여 발병시킨 전파식물을 시험식물 이앙 2주 후에 이식하여 발병을 유도하였다. 발병정도 설정은 병 발생 최성기에 병반면적율에 따라 수준을 설정하고 표식하였다. 병반면적율에 따라 주당이삭수, 이삭당입수, 등숙율, 천립중 그리고 수량에 대한 상관을 분석한 결과 주당이삭수, 등숙율, 수량과는 1%수준에서 -0.97, -1.00, -0.96의 부의 상관이 있었으며, 이삭당입수와 천립중은 1% 수준에서 공히 0.98의 정의 상관이 있었다. 수익역치(GT) 값은 방제비용을 쌀 시장가격으로 나누어 8.35가 되며, 경제적 피해수준(EIL)은 수익역치값을 회귀식의 피해계수로 나눈 값이 된다. 경제적 방제수준(ET)은 EIL값에다 80%를 곱한 값이 된다. 본 시험에서의 경제적 피해허용 수준은 주당 이삭수, 이삭당입수, 등숙율, 천립중, 수량에서 각각 병반면적율 41.77%, 9.74%, 19.01%, 291.06%, 3.36%가 된다. 수량에 대한 경제적 방제수준은 2.7%가 된다($3.4%(EIL){\times}0.8$). 수량에서의 경제적 방제수준은 하위 2엽이 거의 병반으로 덮여 있거나 20개 이상의 대형병반이 하위엽에 발생하였을 때 방제하는 시점으로 나타났다.

• 한국식물병리학회지
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• 제11권4호
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• pp.338-343
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• 1995

Incidence of blast caused by Pyricularia grisea on five new cultivars and four elite lines (C/L) of rice was investigated at different locations, Icheon, Chuncheon, Jecheon and Naju, 1992 to 1994. Disease indices of leaf blast on the tested C/L except Juanbyeo and Keumnambyeo ranged from 0 to 6 in the blast nursery. Under the field conditions, percentages of diseased leaf area of Kuemnambyeo were 6.5% in Jecheon and 2.8% in Icheon in 1993. The incidence of panicle blast on the C/L except Suweon 394 and Milyang 117 differed depending on the locations and years. In case of Unjangbyeo, panicle blast was rarely observed n the fields in Icheon and Naju, but the disease incidences were 21.8% in Jecheon in 1993 and 16.4% in Chuncheon in 1994. Race distribution of the blast fungus was variable according to the locations. The major race in the Jecheon site was KI-197, which was recently identified.

• 식물병과 농업
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• 제5권2호
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• pp.105-110
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• 1999

Bacterial leaf spot by Xanthomonas campestris pv. vesicatoria has been known to cause serious problem in red pepper in Korea. However recent survey showed that most smptoms in the leaves were mixed with two different symptoms one was leaf spot and the other was canker. bacteria isolated from canker were identified as Clavibacter michiganensis subsp. michiganensis on the basis of biochemical and physiological characteristics. The causal bacteria were non-motile rod-shaped and Gram-positive. The lesions on pepper leaves appeared at first as small blisters or pimple-like white spots which enlarged in size at a later stage. The centers of some of the spots became necrotic and brown and were surrounded by a white halo. Pathogenicity tests were performed on pepper cv. Alchan seedling by spraying of bacterial suspension. During 1997 and 1998 total 17% of 527 fields surveyed were infected by C. michiganensis subsp. michiganensis. The canker of red pepper caused by C. michiganensis subsp. michiganensis was first identified in this study in Korea, and new name "gueyangbyung" was tentatively given to the disease.

• 식물병연구
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• 제13권3호
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• pp.152-156
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• 2007

백합을 노지재배할 경우 'Raizan'과 'Casa Blanca' 품종에서 잎마름병의 발병엽율이 각각 50%, 45.4%인 반면, 비가림 시설재배할 경우는 발병엽율이 1.5%, 1.9%로 현저히 감소하였다. 또한 비가림 시설재배에서 스프링클러 관수시에 잎마름병 발생율이 $14.5{\sim}16.5%$였으나 점적 관수시에는 $1.5{\sim}2%$로 감소하였다. 백합 잎마름병 발생에 미치는 연작의 영향을 조사하였던 바 초작지에 비하여 재작지 및 3년 연작지의 병 발생율이 현저히 높았다. 월동한 병든 식물체의 잎, 줄기, 꼬투리, 종구에서 B. elliptica의 분리비율은 43.3%, 46.7%, 60%, 0%, B. cinerea의 분리비율은 10.3%, 0%, 3.3%, 0%였으며, 두 균 모두 백합의 꼬투리에서 가장 높은 비율로 분리되었다. Raizan 품종을 절화한 후 식물체 잔재물을 방치한 포장에서는 다음 해 최고 56.5%의 발병엽율을 나타낸 반면에 잔재물을 제거한 포장에서는 발병엽율이 7.3%로 매우 낮았다. 노지재배시 흑색비닐, 수피, 볏짚을 이용하여 멀칭재배를 한 경우 잎마름병의 발병엽율이 각각 6.6%, 8.2%, 11.3%로서 비멀칭재배의 발병엽율 21.3%에 비해 현저히 감소하였다.

• 식물병연구
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• 제27권4호
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• pp.180-186
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• 2021

경남과 전남의 육묘중인 수박과 정식한 포장의 유묘에서 황색의 둘레무리와수침상의 갈색 및 검은색의 반점의 병반이 관찰되었다. 병반에서 분리한 분리균은 수박과 쥬키니에서 높은 병원성을 보여주었다, 분리균은 4개의 속생모를 가진 막대형 세균이었다. 분리균은 그람음성으로 LOPAT group 1a에 속하였으며, King'B 배지에서 형광성이 없었다. 16S rRNA 유전자 염기서열을 이용한 계통수 분석과 4개의 항존유전자 염기서열(gapA, gltA, gyrB, rpoD)을 이용한 multi-locus sequencing typing 분석 결과 분리균들은 Pseudomonas syringae pv. syringae와 가장 높은 상동성을 보여주었고, 같은 그룹(clade)으로 묶이었다. 또한 이들은 P. syringae genomospecies group 1에 속하였다. 수박의 잎점무늬병징에서 분리한 세균의 형태적, 생리적, 유전적 특징은 이들이 P. syringae pv. syringae임을 제시한다. 본 논문은 한국에서 P. syringae pv. syringae가 수박에서 점무늬병을 일으키는 최초의 보고이다.