• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.4
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• pp.498-504
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• 2014

Potato virus Y (PVY) and potato leafroll virus (PLRV) are among the most damaging potato viruses and prevalent in most potato growing areas. In this study, cryopreservation was used to eradicate PVY and PLRV using two cryogenic methods. Potato shoot tips proliferated in vitro were cryopreserved through droplet-vitrification and encapsulation-vitrification using plant vitrification solution 2 (PVS2; 30% glycerol + 15% dimethyl sulfoxide + 15.0% ethylene glycol + 13.7% sucrose) and modified PVS2. Both cryogenic procedures produced similar rates of survival and regrowth, which were lower than those from shoot tip culture alone. The health status of plantlets regenerated from shoot tip culture alone and cryopreservation was checked by reverse transcription-polymerase chain reaction. The frequency of virus-free plants regenerated directly from highly proliferating shoot tips reached 42.3% and 48.6% for PVY and PLRV, respectively. In comparison, the frequency of PVY and PLRV eradication after cryopreservation was 91.3~99.7% following shoot-tip culture. The highest cryopreserved shoot tip regeneration rate was observed when shoot tips were 1.0~1.5 mm in length, but virus eradication rates were very similar (96.4~99.7%), regardless of shoot tip size. This efficient cryotherapy protocol developed to eliminate viruses can also be used to prepare potato material for safe long-term preservation and the production of virus-free plants.

• Korean Journal of Veterinary Service
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• v.25 no.1
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• pp.87-96
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• 2002

In this study, we wanted to determine if the respirotropic JMK strain of infectious bronchitis virus(IBV), which has a spike glycoprotein gene that is 99% similar to the nephropathogenic Gray strain of IBV, could adapt and cause lesions in the kidney following intracloacal passage in chickens. Two day old specific pathogen free(SPF) cchickens were infected with Gray and JMK strains by the intraocular and cloacal route. Several tissue samples were collected at various times. Viruses were recovered from more tissues and earlier in the infection from chickens infected cloacally than chickens infected intraocularly. Virus was isolated from the kidney of chickens infected with Gray by the intraocular route and JMK by the intracloacal route, but not from chicken given JMK the intraocular route. Histopathologically, interstitial nephritis was observed in Gray infected chickens. However, viral RNA or antigen were not detected in the kidney by in situ hybridization and immunohistochemistry. We further passaged the JMK strain ten times in two day old SPF chickens using cloacal inoculation. We examined the virus titer and histopathological change in the kidney at each passage level. The amount of virus recovered from the kidney was stable throughout this serial passage and the passaged virus did not caused renal damage. Further, virus could not be isolated from the kidney when chickens were infected with the passaged virus by the intraocular route. We conclude that the JMK strain has a strict upper respiratory tract tropism since cloacal passage did not produce nephrotropism or nephropathogenicity.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.107.2-108
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• 2003

Viral disease symptoms were investigated in the field grown Longiflorum hybrid cultivars, and the damages caused by infection with Lily mottle virus (LMoV) and Cucumber mosaic virus (CMV) were assessed by comparing growth of plants produced from seeds of Longiflorum hybrid cultivar both infected by artificial inoculation and free from infection with theses viruses. Dominant symptom caused by spotaneous infection with LMoV and CMV in the field was mottle combined with chlorotic stripe on leaves. LMoV developed brownish necrotic lesion on floral leaves. The incidence of viral disease by mixed infection with LMoV, CMV or Lily symptomless virus (LSV) in the filed grown Longiflorum hybrid cultivar, cultivated for more than 6 years, was 80 to 84 percent. In comparison with virus-free plants, plants doubly infected with CMV and LMoV by artificial inoculation decreased stem length by 14 percent and fresh weight by 38 percent. In conclusion, flower quality and the stem length of Longiflorum hybrid cultivar were affected by LMoV and CMV infection.

• Journal of Plant Biotechnology
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• v.46 no.3
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• pp.228-235
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• 2019

Apple (Malus pumila) is one of the most economically important fruits in Korea. but virus infection has decreased the sustainable production of apples and caused serious problems such as yield loss and poor fruit quality. Virus or viroid infection including apple chlorotic leaf spot virus (ACLSV), apple stem pitting virus (ASPV), apple stem grooving virus (ASGV), apple mosaic virus (ApMV) and apple scar skin viroid (ASSVd) have been also reported in Korea. In many cases, as apple gets infected with virus and viroid with no specific symptoms, the damage and symptoms caused by the viruses are not detected. In our research, viruses in the rootstock were eliminated for a virus-free apple dwarfing rootstock of M.9 and M.26. The virus elimination methods were apical meristem culture, thermotherapy ($37^{\circ}C$, 6 weeks) and chemotherapy($Ribavirin^{(R)}$). The detection of apple viruses was accomplished by Enzyme-linked Immuno-Sorbent Assay (ELlSA) and reverse transcription-polymerase chain reaction (RT-PCR). RT- PCR method was 10 ~ 30% more sensitive than the ELISA method. The efficiency of virus elimination was enhanced in apical meristem culture method. The acquisition rate of virus-free apple dwarfing rootstocks was 30 ~ 40% higher in apical meristem culture. After the meristem culturing of M.9, the infection ratio of ACLSV, ASPV and ASGV was 45%, 60% and 50%, respectively. In the apple dwarfing rootstock of M.26, the infection ratio of ACLSV, ASPV and ASGV was 40%, 55% and 55%, respectively. Based on this study, the best method for the production of virus-free apple dwarfing rootstocks was the apical meristem culture.

• Research in Plant Disease
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• v.9 no.1
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• pp.1-9
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• 2003

The occurrence of potato(Sotanum tuberosum) viral diseases caused by Potato virus X(PVX), Potato virus Y (PVY), Potato leafroll virus(PLRV), Potato vims S(PVS), Potato virus M(PVM), Potato virus A(PVA), Potato virus T(PVT), Alfalfa mosic virus(AIMV), Tobacco mosic virus(TMV), Potato mop top virus(PMTV) Tobacco rattle virus(TRV) and Potato spindle tuber viroid(PSTVd), potato witches' broom phytoplasma, have been identified so far in Korea. Major viral diseases such as PVX, PVY and PLRV had been studied more deeply, however, the others are just identified and only partially characterized since the first study on the relation between PVX nucleic acid and virus protein by Kim in 1961. The most studies on potato viral diseases are mainly focused on the problems of seed potato production. The National Alpine Agricultural Experiment Station(NAAES), since it began its activities in 1961, has given special attention to this problem by doing studies to identify, characterize and control potato virus diseases. This effort resulted in the development of new potato virus detection methods as a basis for elaborating new method of control, such as the production of seed potato free of virus and the selection of new virus-resistant transgenic potatoes. The further studies of potato viral diseases required would be fallowings: the continuous monitoring for the occurrence of identified or not identified potato viruses in Korea, the isolation of resistant viral genes, the development of control method for the non-persistently transmitted viruses like PVY, special vectors such as nematode and fungus transmitted viruses, TRV and PMTV and the development of control methods against potato viral diseases by viral cross protection, therapy, transgenic plant, and the use of the agents or molecules, such as virus inhibitors and antiviral proteins, etc., blocking viral replication.

• Journal of Plant Biology
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• v.4 no.1
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• pp.9-11
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• 1961

A comparative investigation of free amino acids content in healthy check and virus diseased leaves of Chinese date tree, Zyzyphus jujuqa Mill var. inermis Rhed, was carried out by authors throughout the growing season of 1959 and 1960 from June to October. The methods of qualitative analysis of free amino acids aplied in this experiment is followed by Moore and Stein. Free amino acids determined in this experiment are shown in Fig. 1 and Table 1. As the figure and the table are shown, three more amino acids such as glutamine, asparagine and histidine are detected in the diseased material. The additional amino acids which are known as diamines in diseased leaves are conspicuous. It is presumed that the diamine might be incresed by the self-reproduction of the virus in cooporation with certain enzymes which are carrying out the protein metabolism in the host protoplast in contrast with the healthy checks which is carrying out normal protein metabolism. From the histological poing of view, the facts of phloem degeneration or necrosis in diseased leaves, it seems to interrupt to move free amino acids from roots to leaves and it possibly takes place an excessive production of NH3 which is diaminated by the metabolism of nitrogen compounds in such conditioned leaves. Therefore, it is also presumed that additional diamino acids are accumulated in diseased leaves. There are no change of amino acids are accumulated in diseased leaves. There are no change of amino acids in both materials of this plant throughout the growing season qualitatively, and this result agress with the paper of Knight.

• The Plant Pathology Journal
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• v.40 no.1
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• pp.40-47
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• 2024

Garlic can be infected by a variety of viruses, but mixed infections with leek yellow stripe virus, onion yellow dwarf virus, and allexiviruses are the most damaging, so an easy, inexpensive on-site method to simultaneously detect at least these three viruses with a certain degree of accuracy is needed to produce virus-free plants. The most common laboratory method for diagnosis is multiplex reverse transcription polymerase chain reaction (RT-PCR). However, allexiviruses are highly diverse even within the same species, making it difficult to design universal PCR primers for all garlic-growing regions in the world. To solve this problem, we developed an inexpensive on-site detection system for the three garlic viruses that uses a commercial mobile PCR device and a compact electrophoresis system with a blue light. In this system, virus-specific bands generated by electrophoresis can be identified by eye in real time because the PCR products are labeled with a fluorescent dye, FITC. Because the electrophoresis step might eventually be replaced with a lateral flow assay (LFA), we also demonstrated that a uniplex LFA can be used for virus detection; however, multiplexing and a significant cost reduction are needed before it can be used for on-site detection.

• The Plant Pathology Journal
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• v.22 no.3
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• pp.255-259
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• 2006

The pathogenicity to pear trees and other experimental hosts of the Apple stem grooving virus Korean isolate (ASGV-K) carried by a fungal vector, Talaromyces flavus was examined. ASGV-harboring T. flavus induced mild symptoms on virus-free pears. Symptom severity was intermediate between pears showing typical PBNLS and virus-free pears. Ten cultivars of Phaseolus vulgaris showed 35%-90% infectivity by direct infiltration into leaves and roots by ASGV-harboring T. flavus. Application of fungal cultures to soils showed 0%-70% infectivity depending on the P. vulgaris cultivar. Sap extracted from ASGV-infected Chenopodium quinoa induced similar symptoms on P. vulgaris at 25 days after inoculation. Similar symptoms were also detected on P. vulgaris which were inoculated with ASGV-harboring T.flavus. When healthy P. vulgaris leaves were challenged with sap extracted from P. vulgaris leaves infected with ASGV-harboring T. flavus, typical symptoms were observed. These data suggest that T. flavus mediates the transfer of ASGV to host plants.

• Korean Journal of Microbiology
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• v.36 no.4
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• pp.306-311
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• 2000

Infection of Vero cells with herpes simplex virus type-1 (HSV-1) resulted in a series of changes in intra-cellular free calcium concentration $([Ca^{2+}]_i)$. A significant and maximal decrease $[Ca^{2+}]_i$ was observed at 4 hours postinfection (hr p.i.) in HSV-1-infected in Vero cells. Inactivation of HSV-1 with UV irradiation and heat treatment abolished HSV-1-induced decrease in $[Ca^{2+}]_i$ at 4 hr p.i. in Vero cells. And the degree of the decrease in $[Ca^{2+}]_i$ was dependent on the amount of input virus. Taxol, which stabilizes the polymerization of microtubule blocked HSV-1-induced decrease in $[Ca^{2+}]_i$ at 4 hr p.i., suggesting that microtubule may mediate the transport of HSV-1 nucleocapsid to the nucleus of infected cell. Treatment of HSV-1-infected Vero cells with metabolic inhibitors such as cycloheximide, cordycepin, or acyclovir partially reversed the decrease in $[Ca^{2+}]_i$ at 4 hr p.i.. Thus, it is suggested that HSV-1 induced decrease in $[Ca^{2+}]_i$ at 4 hr p.i. in Vero cells may play an important role in the multiplication of HSV-1.

• Horticultural Science & Technology
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• v.33 no.6
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• pp.891-899
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• 2015

The lily symptomless virus (LSV) is the most common virus in Korean native lilies and causes various types of damage to overall plant growth. This study was carried out to investigate the elimination rate of the LSV by the in vitro scale culture (scaling) method in Korean native lilies and to test reinfection rates of the LSV under several field culture conditions of bulb production. Four Korean native lilies (Lilium dauricum, L. distichum, L. lancifolium, and L. maximowitzii) were used and their scales were cultured in vitro for micro-scale formation. The micro-scales were subcultured repeatedly using MS culture medium supplemented with 30 or $90g{\cdot}L^{-1}$ sucrose. The culture conditions were $24{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD with 16 hour daylength using fluorescent lamps and maintained at $22{\pm}2^{\circ}C$. The virus-free bulblets were grown for one to three years in the greenhouse and transplanted to the field in October or March. Virus infection rates were investigated by direct tissue blotting immunobinding assays and measurement of chlorophyll and protein contents. Virus-free plants could be obtained from the 5th subculture of micro-scales in L. lancifolium and L. maximowitzii or from primary culture in L. dauricum and L. distichum. LSV-free plants were reinfected during bulb production in the field. Reinfection rates were higher at older bulb ages and under higher planting density. The plants planted in October and at inland Gyeongsan had higher infection rates than those planted in March and at coastal area Pohang. The reinfection rate of L. maximowitzii was higher than those of L. dauricum and L. lancifolium. The LSV-infected plants had lower chlorophyll contents and unchanged protein contents compared to virus-free plants.