• Korean Journal Plant Pathology
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• v.13 no.2
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• pp.73-78
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• 1997

A virus was purified from Korean cactus (Chamaeaereus silverstrii f. Variegata Hort) showing necrotic spots and its biophysicochemical properties were examined. The typical necrotic spots were observed on healthy looking cactus inoculated with the purified virus and the various symptoms from necrotic spots to systemic were observed on 17 species of test plats used, which suggests that the purified virus has the normal infectivity and wide host range. Ultraviolet absorption scanning analysis revealed that the viral preparation had the typical curve with shoulder at 290 nm and its ratio of absorbances at 260 nm to 280 nm and extinction coefficient was 1.156 and 2.86, respectively. The virus represented one distinct and homogeneous band and molecular weight of viral coat protein was determined to 17, 000 Dalton by SDS-PAGE. The virus revealed rod-shaped virion (325$\times$20 nm) by electron microscopy. Based on these results, it has been thought that the virus purified in this study is the pathogenic agents causing necrotic spot symptom on Korean cacuts and one of the member of tobamovirus family.

• Korean journal of applied entomology
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• v.23 no.4 s.61
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• pp.203-208
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• 1984

Four varieties of tobacco, Nicotiana tabacum var. NC 2326. NC 95, NC 744 and Havana. and two plant species, Physalis floridana Rydb., N. repanda Wild. were used for classification of ten isolates of potato virus Y(PVY) obtained Iron potato or tabacco plants showing various symptoms. Each of the 10 isolates could be distinguished by the host reactions showing necrosis, vein banding and/or mottling, or no symptom on these hosts. Five isolates of PVY, PVY-VN, PVY-N, PVY-NSNR, PVY-Chile, and PVY-Argentina, showed necrotic symptom on NC 2326, but others showed vein handing and/or mottling symptom. On NC95, each of the isolates tested showed similar symptons as on NC2326, except necrotic symptom by the isolate PVY-MSNR. Havana showed mottling reaction to the PVY-NSNR, PVY-MSNR, PVY-MSMR, PVY-VB, and necrosis to PVY-Chile, PVY-Argentina, but showed no symptom to the others. NC744 showed mottling symptom to the PVY-MSNR and PVY-MSMR, necrosis to the PVY-Chile and PVY-Argentina, and no symptom to the others. On N. repanda, necrotic reaction to PVY-Argentina. no symptom to PVY-VN and PVY-C, and nettling to others were observed.

• Research in Plant Disease
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• v.12 no.3
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• pp.221-225
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• 2006

Cucumber mosaic virus(CMV) and Broad bean wilt virus 2(BBWV2) were isolated from Gentiana scabra plants showing typical mosaic and yellowing symptoms. When the inoculum of mosaic symptom propagated in Nicotiana benthamiana was inoculated to primary leaves of Vigna sinensis, the local lesions of different types was developed. Type one produced a small necrotic spot(SNS) of pinpoint type, while the other one showed a large necrotic spot(LNS) of halo type. LNS on primary leaves of V. sinensis was also induced by inoculum from yellowing symptom on G scabra. Single lesion from SNS induced a typical mosaic symptom on N. Benthamiana. On the other hand, LNS produced a chlorotic ring symptom on inoculated leaves and mosaic plus necrotic ringspot on upper leaves of N. benthamiana. An isolate of CMV from SNS and BBWV2 from LNS were detected by using dsRNA analysis, RT-PCR and agar gel double-diffusion test. Thus, our results should provide a tool of a simple method for discrimination from mixed infected plants by CMV and BBWV2.

• The Plant Pathology Journal
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• v.24 no.1
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• pp.93-96
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• 2008

In August 2006, a severe disease incidence showing mosaic and/or necrotic symptoms on two bell pepper varieties including red-colored 'Special' and yellow-colored 'Fiesta' was observed in a greenhouse located in Gwangyang, Jeonnam province, Korea. To identify causal viruses, total RNAs were extracted from 11 fruit samples with and without symptoms. Specific oligonucleotide primers for Cucumber mosaic virus (CMV), Pepper mottle virus (PepMoV), Tomato spotted wilt virus (TSWV) and Pepper mild mottle virus (PMMoV) were designed based on the sequences available on GenBank. Database comparisons of the deduced amino acid sequences of each sequence produced 100% and 98% matches with nucleocapsid protein gene of TSWV (Acc. No. ABE11605) and coat protein gene of CMV (Acc. No. DQ018289), respectively, suggesting that the symptoms on bell pepper fruits might be caused by the infection of CMV and TSWV. To our knowledge this is the first report of necrotic as well as mosaic virus disease on bell pepper fruits by the infection of CMV and TSWV in Jeonnam province, Korea.

• Journal of the Korean Society of Tobacco Science
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• v.7 no.1
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• pp.7-13
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• 1985

Effect of the two PVY strains(PVY-VB and PVY-VN) on yield and chemical constituents of tobacco plants was determined in roar. NC2326 and Burley 21. The virus was inoculated 6 and 8 weeks after transplanting, respectively. The strains and time of inoculation were most critical factors for yield reduction. The greatest reduction was caused by the necrotic strain (PVY-VN) inoculated 6 weeks after transplanting, accounting for the loss of 40% in var. NC2326 and of 45% in var.. Burley21. When inoculated 8 weeks after transplanting with the necrotic strain, only 17% reduction was recorded in roar. Burley21, but no reduction occurred in roar. NC2326. Generally less reduction was caused by the PVY-VB strain, ranging 12-16% depending on the time of inoculation and/or variety. Compared to healthy tobacco, PVY infected tobacco contained higher concentrations of total nitrogen, protein nitrogen, nitrate nitrogen, and lower total sugar in cured leaf of roar. NC2326. Total alkaloid, P, Mg, Ca, and K levels were not altered. In var. Burley21, protein nitrogen and nitrate nitrogen increased, but other chemical components were not changed. Necrotic strain-infected tobacco with a severe symptom had higher nitrogen than did mild strain-infected tobacco.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.151.1-151
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• 2003

Chinese yam(D. opposita Thunb. cv. Jang-Ma) plants showing necrotic mosaic symptom were collected from their growing fields in Andong, Korea. Electron microscoptic examination of negatively stained preparations showed filamentous particles of 660nm in length. The virues purified partially were used to isolate Viral RNA as template for RT-PCR to amplify the CP gene with ChYNMV specific and oligo dT primers. Amino acids sequeces revealed that the viruses shared 99.3％ similarity with ChYNMV(AB044386) which was known as the member of macluravirus. So the viruses from Chinese yam(D. opposita Thunb. cv. Jang-Ma) plants were identified as ChYNMV. Comparing the amino aced sequences of ChYNMV strains with other macluraviruses such as CdMV, NLV and MacMV revealed that N-terminal was the most variable region and conserved regions were present within the genus Macluravirus.

• The Plant Pathology Journal
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• v.31 no.4
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• pp.379-387
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• 2015

Melon necrotic spot virus (MNSV) was recently identified on watermelon (Citrullus vulgaris) in Korea, displaying as large necrotic spots and vein necrosis on the leaves and stems. The average occurrence of MNSV on watermelon was found to be 30-65% in Hapcheon and Andong City, respectively. Four isolates of the virus (MNSV-HW, MNSV-AW, MNSV-YW, and MNSV-SW) obtained from watermelon plants in different areas were non-pathogenic on ten general indicator plants, including Chenopodium quinoa, while they infected systemically six varieties of Cucurbitaceae. The virus particles purified by 10-40% sucrose density gradient centrifugation had a typical ultraviolet spectrum, with a minimum at 245 nm and a maximum at 260 nm. The morphology of the virus was spherical with a diameter of 28-30 nm. Virus particles were observed scattered throughout the cytoplasm of watermelon cells, but no crystals were detected. An ELISA was conducted using antiserum against MNSV-HW; the optimum concentrations of IgG and conjugated IgG for the assay were $1{\mu}l/ml$ and a 1:8,000-1:10,000 dilutions, respectively. Antiserum against MNSV-HW could capture specifically both MNSV-MN from melon and MNSV-HW from watermelon by IC/RT-PCR, and they were effectively detected with the same specific primer to produce product of 1,172 bp. The dsRNA of MNSV-HW had the same profile (4.5, 1.8, and 1.6 kb) as that of MNSV-MN from melon. The nucleotide sequence of the coat protein of MNSV-HW gave a different phylogenetic tree, having 17.2% difference in nucleotide sequence compared with MNSV isolates from melon.

• Journal of the Korean Society of Tobacco Science
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• v.5 no.1
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• pp.43-47
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• 1983

Tobacco mosaic virus (TMV) was detected from Kimchi by biological and serological assay 5. Kimchi samples three month after cooked were collected, and were inoculated on N. tabacum var. Burley 21 and NC 95. Out of 33 samples, 6 showed typical symptoms induced by TMV, local necrotic lesions on Burley 21 and mosaic on NC 95. All saps from tobacco leaves showed the mosaic symptom reacted positively against TMV antiserum by agar gel double diffusion test. Based on the results, the Kimchi is considered as one of the important inoculum sources in Korea.

• Korean Journal Plant Pathology
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• v.13 no.2
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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.

• The Plant Pathology Journal
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• v.31 no.4
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• pp.421-427
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• 2015

Citrus scab disease is one of the destructive diseases that reduce the value of fruit for the fresh market. We analyzed the process of symptom development after infection with scab pathogen $Elsino{\ddot{e}}$ fawcettii in the susceptible satsuma mandarin leaves to observe the structural modification against pathogen. The cuticle and epidermal cells along with 3-5 layers of mesophyll tissue were degraded 1-2 days post inoculation. Surrounding peripheral cells of degraded tissues grew rapidly and then enveloped the necrotic area along with the growing conidia. Cross sections through the lesion revealed hyphal colonization in epidermis and mesophyll tissues. In response to the pathogen colonization, host cell walls were lignified, inner cells were rapidly compartmentalized and a semi-circular boundary was formed that separated the infected region from the non-infected region, and finally prevented the intercellular pathogen spread.