• 한국식물병리학회지
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• 제13권2호
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• pp.132-137
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• 1997

Phytotoxicity of the culture filtrate and culture conditions for the production of the phytotoxin by Exserohilum monoceras 92-044 were examined. The necrotic lesions were developed on the leaves of Echinochloa crus-galli within 48 hrs after inoculation of the culture filtrate, and the leaves were completely blighted within 5∼7 days. Maximum toxicity was found in the culture broth containing 20% V-8 juice. Phytotoxin accumulation and fungal growth reached their highest peak at around 11 days. Typical symptom appeared on the leaf of E. crus-galli within 48 hrs. Only a weak chlorosis appeared on rice, Arundinella hirta (THUNB) and henry crabgrass (Digitaria sanguinalis SCOP.), but no further symptom developed.

• 식물병연구
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• 제10권2호
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• pp.145-149
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• 2004

사과 '홍로' 품종은 품질이 우수하여 재배면적이 증가되고 있는 중요한 품종으로 최근 일부 농가에서 과실 크기가 작아지면서 과육이 딱딱해지고 과즙이 거의 없어지는 소과증상이 발생되고 있어 재배현장에서 문제가 제기되고 있다. '홍로' 품종의 소과증상은 주요 재배지역에서 조사한 결과 조사농가당 홍로품종 재배주수의 평균 12%정도 발생되고 있었으며 ELISA에 의한 바이러스 진단 결과 소과 발생나무에서 고농도의 ACLSV가 100% 검출되었다. 즙액 접종한 C. quinoa에서 ACLSV가 분리되었으며, 접목 접종한 목본지표식물에서도 잎 상편생장 및 줄기괴사 병징을 나타내어 접목전염성이 확인되었다. 소과증상의 원인 구명을 위해 열처리와 생장점배양으로 육성된 바이러스 무독주에 인위적으로 ACLSV 등 바이러스를 접목접종 한 다음 결실된 과실의 특성을 조사한 결과 ACLSV 접종주에서 소과증상이 발생되는 것을 확인할 수 있었다. 결론적으로, 소과증상을 일으키는 주된 요인이 ACLSV 감염에 의한 것으로 판단되며 국내 육성종인 '홍로' 품종은 ACLSV에 대한 감수성 품종으로 분류될 수 있을 것으로 판단된다.

• 식물병과 농업
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• 제1권2호
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• pp.18-21
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• 1995

Mycosphaerella nawae, the causal organism, of spotted leaf casing disease of persimmon, was isolated from infected leaves showing typical symptom. The cultural characteristics of the fungus were compared on artificial media. Among 24 different combinations of culture media and supplements, oatmeal agar+persimmon leaf extract (PLE) and PAD+ PLE+streptomycin showed the highest rate of isolating as 57.1%. The best medium for mycelial growth of the fungus was PDA+persimmon leaf powder (PLP). The colony diameter was reached 47mm for 30 days at 2$0^{\circ}C$. PDA+PLE also supported good mcyelial growth showing 46mm of diameter in same condition. The optimum growth temperature of this fungus in PDA was recognized fairly low. The mycelial growth was higher at 2$0^{\circ}C$ than 15$^{\circ}C$. The variation of pH between pH 4 to pH 8 did not affect to the mycelial growth of the pathogen.

• The Plant Pathology Journal
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• 제17권3호
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• pp.128-140
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• 2001

Infection of pepper leaves by Colletotrichum cocodes at the two- and eight-leaf stages caused susceptible and resistant lesions 96 h after inoculation, respectively. At the two-leaf stage, progressive symptom development occurred on the infected leaves. In contrast, localized necrotic spots were characteristic symptoms at the eight-leaf stage. Infected leaves at the two-leaf stage exhibited cell death accompanied by the accumulation of autofluorescent compounds. At the eight-leaf stage, pepper leaves infected by the anthracnose fungus displayed localized autofluorescence from the symptoms. Infection of pepper leaves by C. cocodes at the two-leaf stage resulted in its rapidand massive colonization of all the leaf tissues including the vascular tissue, together with cytoplasmic collapse, distortion of chloroplasts, and disruption of host cell walls. However, penetration of C. cocodes was very limited in the older leaf tissues of pepper plants at the eight-leaf stage. Fungal hyphae grew only in the intramural spaces of the epidermal cell walls at this stage. Occlusion of amorphous material in xylem vessels, aggregation of fibrillar material in inter-cellular spaces, and deposition of protein bodies were found as resistance responses to C. cocodes.

• 한국약용작물학회지
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• 제22권1호
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• pp.32-37
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• 2014

To study the cause of physiological disorder in leaf of ginseng cultivated at paddy soil, the degree of brown-colored symptom (BCS) and the contents of inorganic matter in leaf were investigated by irrigating the solution of ferric and ferrous iron of 0.1 ~ 2.0%, and citric acid of 1.0 ~ 4.0% on bed soil, respectively. Ratio of BCS by variety was as high as 85.0% in Yoenpoong, while it was as low as 5.4%, 7.5% in Chunpoong and Hwangsook, respectively. The contents of inorganic matter of leaf in Yoenpoong were lower in $P_2O_5$, Ca, and Mg, while it were higher in K, Fe, and Mn than other variety. Iron solution caused BCS more distinctly when each ferric and ferrous iron were dissolved with 1.0% citric acid than when each iron was dissolved without citric acid. Ferric iron caused BCS more effectively than ferrous iron. BCS occurred in 4.0% citric acid was as same as 2.0% ferric iron mixed with 1.0% citric acid. Low $P_2O_5$ and high Fe content in leaf appeared in both of artificial and natural symptoms. We concluded that excessive Fe uptake caused BCS to leaf because the solubility of iron was increased in condition of low soil pH.

• The Plant Pathology Journal
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• 제32권5호
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• pp.377-387
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• 2016

Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus, is one of the most important viruses of cultivated tomatoes worldwide, mainly causing yellowing and curling of leaves with stunting in plants. TYLCV causes severe problems in sub-tropical and tropical countries, as well as in Korea. However, the mechanism of TYLCV infection remains unclear, although the function of each viral component has been identified. TYLCV C4 codes for a small protein involved in various cellular functions, including symptom determination, gene silencing, viral movement, and induction of the plant defense response. In this study, through yeast-two hybrid screenings, we identified TYLCV C4-interacting host proteins from both healthy and symptom-exhibiting tomato tissues, to determine the role of TYLCV C4 proteins in the infection processes. Comparative analyses of 28 proteins from healthy tissues and 36 from infected tissues showing interactions with TYLCV C4 indicated that TYLCV C4 mainly interacts with host proteins involved in translation, ubiquitination, and plant defense, and most interacting proteins differed between the two tissues but belong to similar molecular functional categories. Four proteins-two ribosomal proteins, S-adenosyl-L-homocysteine hydrolase, and 14-3-3 family protein-were detected in both tissues. Furthermore, the identified proteins in symptom-exhibiting tissues showed greater involvement in plant defenses. Some are key regulators, such as receptor-like kinases and pathogenesis-related proteins, of plant defenses. Thus, TYLCV C4 may contribute to the suppression of host defense during TYLCV infection and be involved in ubiquitination for viral infection.

• 식물병연구
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• 제10권4호
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• pp.209-216
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• 2004

The circular leaf spot of persimmon is occurred almost every place where persimmon is cultivated, especially the disease outbreak severely in southern part of Korea. The disease reveals unusually long incubation period after pathogen invade into leaf tissue and no practical control measure is available once the symptom has appeared. Most of the farmers just follow the suggested spray schedules calculated on the basis of weather condition of ordinary years. Therefore the damages due to circular leaf spot greatly differ year after year. In this article, we tried to describe and summarized the investigation on the circular leaf spot pathogen, Mycosphaerella nawae, related to disease outbreak such as overwintering of pathogen, inoculum formation and spread, incubation period after infection, and secondary inoculum. With the summary of these results, we suggest the disease cycle of circular leaf spot of persimmon. The pathogen overwinters in diseased leaves as mycelial form or pseudoperithecial premodium. The pseudoperitheria become matured in spring as the temperature raise and forms asci and ascospores. The maturation of pseudoperithecia are closely related to the temperatures during March and early April. The ascospores completely mature in early May and the ascospores released when the pseudoperithecia absorbed enough moisture after rainfall. The release of ascospores are diverse greatly with the variation of maturity of pseudoperithecia. Generally the spore start to release from middle of May to early of July. Duration of ascospore release is depend on the weather condition of particular year, especially amount and number of precipitation. The ascospores produced from pseudoperithecia is known to the only inoculum for circular leaf spot disease. But according to the results obtained from our investigations, the conidia formed on the lesions which incited by natural infection. This conidia are infectious to persimmon leaves and formed identical symptom as natural infection. The time of producing secondary inoculum of circular leaf spot of persimmon is considered too late to develop new disease. Generally the importance of secondary inoculum is low but the conidia produced in early September are competent to develop new disease and new infection also significantly affect to harvest of persimmon. The importance of circular leaf spot disease is recognized well to farmers. The approaches to control of the disease should be initiated on the basis of the knowledges of inoculum dynamics and ecology of disease development. The forecasting system for circular leaf spot is need to be developed.

• 생물환경조절학회지
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• 제27권3호
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• pp.222-230
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• 2018

본 실험은 LED 광원이 시금치 품종 별 생육, 잎 형태변화 및 세포 길이에 대한 영향을 구명하고자 수행하였다. 최아된 시금치(Spinacia oleracea.) 품종 '월드스타'와 '수시로'를 버미큘라이트에 육묘한 후 NFT 시스템에 정식 한 뒤 LED 적색광(R), 청색광(B), 혼합광(적색:청색=2:1)(RB) 및 백색광(W)에서 $130{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD 광도로 25일간 재배하였다. 정식 후 일주일 간격으로 25일 동안 엽장, 엽폭, 엽병, 엽수, 광합성률을 측정하였고, 상편생장지수(leaf epinasty index, LEI)는 잎이 최대로 전개된 후에 측정하였다. 상편생장이 발생된 잎 가운데와 가장자리를 자른 조직의 세포길이, 폭 및 세포면적은 400배율 광학현미경을 이용하여 측정하였다. 정식 후 25일째에는 엽면적, 뿌리길이, 지상부 및 지하부의 생체중, 건물중을 조사하였다. 지상부 생체중과 건물중, 엽수, 엽면적 모두 월드스타 품종이 수시로 품종에 비해 유의적으로 높았다. 건물중은 월드스타 품종의 경우 혼합광(RB)와 적색광(R) 두 처리구에서 청색광(B)와 흰색광(W) 두 처리보다 약 35% 유의적으로 높았다. 수시로 품종의 경우 혼합광(RB) 처리구에서 지상부 건물중이 가장 높아 건물중이 가장 낮았던 흰색광(W) 처리구에 비해 40% 높은 건물중 결과를 보였다. 두 품종 모두 혼합광(RB)와 적색광(R) 두 처리구에서만 정식 21일 이후 잎 상편생장(leaf epinasty)이 나타났고 적색광(R) 처리구에서 혼합광(RB) 처리구 보다 유의적으로 높아 잎 상편생장은 적색광(R)과 관련이 있는 것을 알 수 있었다. 잎 가운데와 가장자리 부위 세포크기를 현미경으로 관찰한 결과 두 품종 모두 상편생장이 나타난 적색광(R) 처리구의 잎 가장자리 세포밀도가 잎 가운데 보다 낮은 것으로 나타나 앞서 보고된 연구결과들에서 제시한 상편생장과 잎 가운데와 가장자리 부위의 세포크기 차이 연관성을 뒷받침하고 있다. 또한 청색광(B)이 적색광(B)에서 발생되는 상편생장을 완화시켜주는 역할을 하는 것으로 보여 앞으로 두 광원의 적절한 혼합비율 규명이 필요한 것으로 판단된다. 또한, 엽형 변화가 심했던 수시로 품종보다는 월드스타 품종이 LED 광원을 이용한 식물공장 재배에 더 적합한 것으로 판단된다.

• 한국작물학회지
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• 제36권5호
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• pp.459-480
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• 1991

인삼의 생리장해를 산지중심으로 증상별로 종합검토하였다. 뿌리의 장해는 적피, 은피, 동해, 동해, 근부, 안삼, 출아불재, 달래삼, 소수가 있고 지상부에는 황엽, 조기낙엽, 소엽, 지엽, 백반엽, 동해, 풍해와 경열이 있다. 적피와 황엽이 인삼생산에 가장 크게 영향한다. 농약해, 붕소과 잉해 및 산업공해에 의한 피해 경우도 보고되었다. 원료수삼 가공한 후의 품질요인에 관계되는 생리장해들도 검토하였다.

• Journal of Forest and Environmental Science
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• 제39권1호
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• pp.49-54
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• 2023

For unknown reasons, a few trees in a private chestnut orchard in Icheon si, Gyunggi-do suffered leaf chlorosis and growth decline. Based on symptoms, phytoplasma was a probable cause. Leaf samples were collected from two symptomatic and non-symptomatic trees in the orchard for phytoplasma detection. An amplicon of about 1.2 bp size was obtained from both symptomatic trees by PCR with the universal 16S rDNA primers. Sequences of these amplicons were found to have 99% nucleotide sequence identity to the corresponding genomic region of 16SrIII (X-disease group). More than 100 phytoplasma isolates, such as Candidatus phytoplasma pruni, Milkweed yellows phytoplasma, Goldenrod yellows phytoplasma, Tsuwabuki witches'-broom phytoplasma, Candidatus Phytoplasma trifolii, etc. were involved in the list. Phylogenetic analysis revealed that the sequence obtained in this study closely clustered with Candidatus phytoplasma groups. While one of the amplicons shared 91% identity with the Candidatus phytoplasma castaneae, the other shared only 47%. It needs further analysis and investigation to determine the exact taxonomy. Meanwhile, based on the analysis of the sequences, chlorosis, and small leaves were associated with phytoplasma.