• The Plant Pathology Journal
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• v.22 no.3
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• pp.235-238
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• 2006

Chrysanthemum stunt viroid (CSVd) induced systemic symptoms on chrysanthemum. We detected small RNAs of approximately 22 nucleotides with sequence specificity to CSVd in chrysanthemum infected with CSVd: an indication of the presence of RNA silencing. Regardless of symptom differences associated with CSVd, the small RNAs distributed similarly in amount. Small RNAs were detected with partial-length or full-length probes, indicating that they are not restricted to specific viroid regions but likely representing most of the viroid molecule.

• The Plant Pathology Journal
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• v.17 no.4
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• pp.194-200
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• 2001

Chrysanthemum stunt viroid (CSVd) ws identified in chrysanthemum cv. Chunkwang showing symptoms of stunt with leaf distortion (K1) and stunt with chlorosis of leaves (K2) collected from the main cultivation area of Masan, Kyongnam province in Korea. The specific RNAs related with the diseased chrysanthemums were detected. Full-length 354 bp CSVd cDNAs were amplified from infected tissue by reverse transcription and polymerase chain reaction using a pair of primers specific for CSVd sequence. The amplified cDNA products were analyzed by agarose gel electrophoresis and the specific cDNAs were cloned. Nucleotide sequences of the two CSVd isolates K1 and K2 varied. Phylogenetic analysis of the nucleotide sequences of CSVd isolates indicated that K1 was closely related with J2 and Am 2 isolates. K1 and K2 were transmitted by grafting to Dendranthema grandiflorum cv. Mistletoe, Gynura aurantiaca, and Lycopersicon esculentum cv. Rutgers. This is the first report of CSVd in D. grandiflorum in Korea.

• The Plant Pathology Journal
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• v.24 no.1
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• pp.31-35
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• 2008

The presence of Chrysanthemum stunt viroid (CSVd) in seed and pollen of diseased chrysanthemum was demonstrated. In seeds infected male parent from crosses in May, CSVd was transmitted to 6.7% of the progeny seedlings, whereas if the female parent was infected, CSVd transmission rate was between 46.9 and 75.7%. A relatively high incidence of 94.4 to 96.0% seed transmission occurred when both parents were infected. In seeds infected male parent from crosses in December, no progeny seedlings were infected with CSVd, whereas if the female parent did, CSVd transmission rate was 1.5%. When both parents were infected, 6.9% seed transmission was occurred. The seed transmission rate depended on the temperature when the crosses were made. CSVd was not detected in the non-infected female parent pollinated with infected pollen but was transmitted to the progenies. This is the first report of seed-borne transmission of CSVd in chrysanthemum.

• The Plant Pathology Journal
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• v.21 no.4
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• pp.377-382
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• 2005

Infection rate of Chrysanthemum stunt viroid (CSVd) in 64 commercial chrysanthemum cultivars cultivated in Korea ranged from 9.7 to 66.8$\%$. Symptoms on leaves of CSVd-infected chrysanthemum included yellow spots, chlorosis, vein clearing, vein bending and crumpling. CSVd induced flower malformation in 'Scot', color change in 'Sharotte', and color breaking in 'Sharon'. CSVd caused reduction of plant height, leaf size, flower size and the flowers number by $32-50\%,\;26-35\%$, $14-36\%\;and\;14-75\%$, respectively. In conclusion, CSVd affected plant height, leaf size and flower quality in chrysanthemum plants.

• The Plant Pathology Journal
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• v.30 no.1
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• pp.68-74
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• 2014

Chrysanthemum stunt viroid (CSVd), a noncoding infectious RNA molecule, causes seriously economic losses of chrysanthemum for 3 or 4 years after its first infection. Monomeric cDNA clones of CSVd isolate SK1 (CSVd-SK1) were constructed in the plasmids pGEM-T easy vector and pUC19 vector. Linear positive-sense transcripts synthesized in vitro from the full-length monomeric cDNA clones of CSVd-SK1 could infect systemically tomato seedlings and chrysanthemum plants, suggesting that the linear CSVd RNA transcribed from the cDNA clones could be replicated as efficiently as circular CSVd in host species. However, direct inoculation of plasmid cDNA clones containing full-length monomeric cDNA of CSVd-SK1 failed to infect tomato and chrysanthemum and linear negative-sense transcripts from the plasmid DNAs were not infectious in the two plant species. The cDNA sequences of progeny viroid in systemically infected tomato and chrysanthemum showed a few substitutions at a specific nucleotide position, but there were no deletions and insertions in the sequences of the CSVd progeny from tomato and chrysanthemum plants.

• The Plant Pathology Journal
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• v.22 no.2
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• pp.152-154
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• 2006

CSVd-infected chrysanthemum plants grown under $10^{\circ}C\;or\;15^{\circ}C$ growth chamber for 2 months resulted a higher dilution endpoint of template RNA for Reverse transcription and polymerase chain reaction (RT-PCR) than those grown for 1 month: $10^{-4}(1.35{\times}10^{-2}ug/ml)$ for 1 month, and $10^{-3}(1.35{\times}10^{-1}ug/ml)$ for 2 months. Independent experiment, shoots cut from CSVd (Chrysanthemum stunt viroid)-in footed chrysanthemum plants grown under $10^{\circ}C\;or\;20^{\circ}C$ growth chamber for 2 months showed the same CSVd concentration as control($30^{\circ}C$) at 8 weeks after moving them to normal green-house condition($30^{\circ}C$). From those results, it was concluded that even though the concentration of CSVd was reduced in plants grown at low temperatures, when they were moved to normal glass-house temperature CSVd concentration increased to that of untreated plants in 8 weeks. This conclusion was supported by the rapid replication of CSVd in chrysanthemum after infection.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1999.10a
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• pp.18.1-18
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• 1999

• Research in Plant Disease
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• v.28 no.4
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• pp.237-244
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• 2022

Chrysanthemum plants are one of the most economically important plants in South Korea. Both virus and viroid can cause diseases and economic damage to the plants. In this study, we investigated the detection of seven viruses and two viroids in 350 chrysanthemum plants cultivated in Yesan-gun, Chungcheongnam-do. Two viruses, chrysanthemum virus B (CVB) and tomato aspermy virus (TAV), and two viroids, chrysanthemum chlorotic mottle viroid (CChMVd) and chrysanthemum stunt viroid (CSVd), were detected in this study. The two viruses were detected in six samples and one sample, respectively. The two viroids were detected in 97 samples and 21 samples, respectively. The nucleotide sequences of the CVB-CN-Y, TAV-CN-Y, CChMVd-CN-Y, and CSVd-CN-Y obtained in this study showed 83.7-86.9%, 99.2-100.0%, 94.4-99.5%, and 95.7-99.7% identity, respectively, compared to their other strains/isolates. The CVB-CN-Y and TAV-CN-Y showed the greatest nucleotide sequence homology to CVB-GS1 and three TAV isolates (TAV-V, TAV-P, and TAV-ChJ), respectively. The CChMVd-CN-Y and CSVd-CN-Y showed the greatest nucleotide sequence homology to CChMVd-Horst and four CSVd isolates (Au1.1, K4pop, Sagae, and Tochigi), respectively. This study is the report on the infection rate of viruses and viroids in chrysanthemum plants cultivated in Yesan-gun in 2021.

• Journal of Practical Agriculture & Fisheries Research
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• v.22 no.1
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• pp.131-142
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• 2020

Chrysnathemum stunt viroid (CSVd), a small, single-stranded, infectious RNA, has caused a severe problem in chrysanthemum in the world. In Korea, since CSVd was firstly observed in 1997, the disease has been spread throughout the whole country rapidly. In spite of the seriousness, few methods for control of CSVd have been known without prevention. The use of resistant cultivars is one of the most efficient approaches for overcoming CSVd disease in chrysanthemum cultivation. This study was carried out to identify chrysanthemum genetic resources for the resistance to chrysanthemum stunt viroid (CSVd). A total of 192 commercial cultivars including 167 spray and 25 standard chrysanthemum were screened with CSVd through grafting inoculation method. In most of the inoculated cultivars, typical disease symptoms, stunting of plant height, reduced flower size, and flower color bleaching, were induced. Several cultivars, however, were symptomless or showed delay in symptom expression. Of 192 chrysanthemum cultivars, two cultivars with less than 5% of the average reduction rate of plant height, 'Chiwerel' and 'Jeongheungdaesin', were rated as resistant. And six cultivars less than 20% inculding 'Inga' were rated as moderate resistant. The remaining 184 cultivars with a high level of reduction were rated as susceptible. We expect that these genetic resources can be used in crossbreeding programs for developing CSVd resistant cultivars of chrysanthemum.

• Research in Plant Disease
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• v.17 no.3
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• pp.334-341
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• 2011

The kinds of crop requested from agricultural actual places of famers, Agricultural extension services and so forth was 8 including red pepper for vegetables, 4 including apple for fruit trees and 6 including chrysanthemum for flowers in 2010. The important vegetables in clinical diagnosis of viral diseases were tomato, watermelon and red pepper having the requested rate of 31.8%, 21.4% and 19.5%, respectively. On fruit trees, grape and apple were most common with the requested rate of 63.6% and 33.0%, orderly. On floral crops, tulip and cactus were damaged by viral diseases with the requested rate of 60.0% and 20.0%, orderly. On peppers and tomatoes, six viruses including Cucumber mosaic virus (CMV) and Broad bean wilt virus 2 (BBWV2) infected. Five viruses including Melon necrotic spot virus (MNSV) and CMV were identified from watermelons. On grapes, six viruses including Grapevine fleck virus (GFkV) infected. CMV was identified from six vegetables including pepper out of 8 kinds of vegetables and tulip plant. Total agents of virus and viroid species were 32 and 4 species, respectively, in 2010. Tomato yellow leaf curl disease by Tomato yellow leaf curl virus and Tobacco yellow leaf curl virus was occurred newly at 18 Si/Gun areas including Buan, Jeonbuk province in 2010 and the total areas were increased up to 58 Si/Gun from the first incidence in 2008. Tomato spotted wilt virus (TSWV) occurred newly at two areas of Jinan, Jeonbuk and Jeju in Jeju province in 2010, and the incidence areas were expanded to 25 Si/Gun areas from severe occurrence at Anyang area in 2004. No incidence of TSWV was recorded only in Gyeongbuk and Chungbuk province. Tomato bushy stunt virus occurred newly at Jinju, Gyeongnam, and it had the total incidence areas of 5 Si/Gun after first observation at Sacheon, Gyeongnam in 2004.