• The Plant Pathology Journal
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• 제39권1호
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• pp.28-38
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• 2023

Plant viruses are responsible for worldwide production losses of numerous economically important crops. The most common plant RNA viruses are positivesense single-stranded RNA viruses [(+)ss RNA viruses]. These viruses have small genomes that encode a limited number of proteins. The viruses depend on their host's machinery for the replication of their RNA genome, assembly, movement, and attraction to the vectors for dispersal. Recently researchers have reported that chloroplast proteins are crucial for replicating (+)ss plant RNA viruses. Some chloroplast proteins, including translation initiation factor [eIF(iso)4E] and 75 DEAD-box RNA helicase RH8, help viruses fulfill their infection cycle in plants. In contrast, other chloroplast proteins such as PAP2.1, PSaC, and ATPsyn-α play active roles in plant defense against viruses. This is also consistent with the idea that reactive oxygen species, salicylic acid, jasmonic acid, and abscisic acid are produced in chloroplast. However, knowledge of molecular mechanisms and functions underlying these chloroplast host factors during the virus infection is still scarce and remains largely unknown. Our review briefly summarizes the latest knowledge regarding the possible role of chloroplast in plant virus replication, emphasizing chloroplast-related proteins. We have highlighted current advances regarding chloroplast-related proteins' role in replicating plant (+)ss RNA viruses.

• Journal of Microbiology
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• 제34권1호
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• pp.61-67
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• 1996

Double-stranded RNA (dsRNA) viruses and single-stranded RNA(ssRNA) viruses were detected in a strain of Pleurotus mushroom cultivated in a farm. Those fungal virsus were purified in the pH 6.0 or pH 7.2 using CsCI or Cs$_{2}$SO$_{4}$ buoyant density centrifugation. Each viral particles were not completely separated at any trials. However, mushroom bacili-form virus contains a single major nucleic acid with 0.7 Kb ssRNA, which might code for 20 Kd viral capsid protein. The dsRNAs are encapsidatred into spherical-form viruses, whereas ssRNA viral genomes are encapsidated into two different sizes of bacili-form particles. A healthy-looking mushroom also contained some spherical-form viruses with dsRNAs. Laboratory strains of Pleurotus ostreatus and a cultivated strain of P. sajor-caju did not show any viral particles. Mushrooms with specific disease symptoms. however, contained at least four different sizes of spherical-form viruses. Thus, we concluded that a bacilli-form virus case a severe disease symptoms of adnormal on mushroom development.

• The Plant Pathology Journal
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• 제27권3호
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• pp.197-206
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• 2011

RNA silencing has had a large impact on biology in general, as well as on our understanding of plant-pathogen interactions, especially interactions between plants and viruses. While most of what we know about the mechanism of RNA silencing was deduced in the last 12 years, many of the interactions between plants and viruses, as well as virus-virus interactions in plants, which we now know are manifestations of RNA silencing, were the subject of decades of work from numerous laboratories. These laboratories were examining the nature and extent of phenomena such as recovery from infection, the formation of dark green islands resistant to re-infection, synergy between unrelated viruses and cross-protection between related viruses, all first described in the late 1920s. In this review, the relationships between these phenomena and their place in the defense mechanism we call RNA silencing will be described, to show how they are all linked.

• 식물병연구
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• 제27권4호
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• pp.137-148
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• 2021

식물 RNA 바이러스는 전세계적으로 작물 생산량에 큰 손실을 일으키는 주요 병원체 중 하나로, RNA 바이러스가 갖는 특징인 짧은 복제 주기, 게놈 복제 중의 높은 변이 발생률 등으로 인해 높은 유전적 다양성과 적응성을 가지며 진화해 왔다. 식물 RNA 바이러스는 유전적 다양성을 갖는 유사종 군집으로 존재하며, 환경 변화에 따른 선택압으로 새로운 적합성을 갖는 군집으로의 변천이 빠르게 일어날 수 있다. 식물의 저항성은 일종의 선택압으로 작용하여 바이러스의 적합성에 영향을 미치며, 이는 기주의 저항성을 극복하는 변이 바이러스의 출현으로 이어질 수 있다. 본 논문에서는 식물 RNA 바이러스에 대한 진화적 관점 및 진화의 원동력을 소개하고, 이를 바탕으로 식물 저항성을 극복하는 변이 바이러스의 출현 기작을 다루고자 한다. 또한 바이러스병에 대한 저항성 전개 및 내구성 향상을 위한 전략에 대해 논하였다.

• 한국식물병리학회지
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• 제11권4호
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• pp.367-373
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• 1995

The cDNAs derived from the coat protein (CP) genes of six plant RNA viruses, tobacco mosaic virus-pepper strains (TMV-P) and -ordinary strain (TMV-OM), potato virus Y (PVY), turnip mosaic virus (TuMV), cucumber mosaic virus (CMV) and potato leafroll virus (PLRV), were subcloned into the transcription vector, pSPT18, containing SP6 and T7 promoters. The digoxigenin (DIG)-labeled RNA polymerase after linearlization of the cloned pSPTs with XbaI or SacI, and were tested for their sensitivities for the detection of the six viruses. In slot-blot hybridization, dilution end points for the detection of TMV-P and TMV-OM were 10-4, while those of PVY, TuMV and CMV were 10-3. PLRV was detected at the dilution of 10-2. When each RNA probe was applied for the detection of the viruses in the preparations from the leaf disks (8 mm in diameter, and 12 to 15 mg in weight) of infected natural host plants, TMV-P, TMV-OM and TuMV could be detected from one disk, while PVY from 1 or 2 disks. CMV was detected in the preparation from two disks, and PLRV from three disks. With DIG-labeled RNA probe, PVY was detected at 5 days after inoculation, but with ELISA the virus was detected at 8 days after inoculation to tobacco (Nicotiana tabacum cv. Xanthi nc) plants on which symptoms appeared at 9 days after inoculation. No difference was observed in cross reaction between the RNA probes for the detection of TMV-P and TMV-OM.

• The Plant Pathology Journal
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• 제21권1호
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• pp.13-20
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• 2005

Chlorella viruses are large icosahedral, plaque-forming, dsDNA viruses that infect certain unicellular, chlorellalike green algae. The genomic DNA of over 300 kb contains many useful genes and promoters. Over 40 chlorella viruses have been isolated from fresh water in Korea since 1998. The viruses were amplified initially in chlorella strain NC64A, and pure isolates were obtained by repeated plaque isolation. SDS-PAGE analysis revealed similar but distinct protein patterns, both among the group of purified viruses and in comparison with the prototype chlorella virus PBCV-1. Digestions of the 330- to 350-kb genomic DNAs with 10 restriction enzymes revealed different restriction fragment patterns among the isolates. The tRNA-coding regions of 8 chlorella viruses were cloned and sequenced. These viruses contain 14-16 tRNA genes within a 1.2- to 2-kb region, except for the SS-1 isolate, which has a 1039-bp spacer in a cluster of 11 tRNA genes. Promoter regions of several early genes were isolated and their activities were analyzed in transformed chlorella. Some promoters showed stronger activity than commonly used CaMV 35S promoter and chlorella transformation vectors for heterologous protein are beings constructed using these promoters.

• 미생물학회지
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• 제43권4호
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• pp.285-291
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• 2007

볼티모어의 분류체계에 의하면 바이러스는 복제 및 단백질합성 전략에 따라 6개의 집단으로나눌 수 있다. 몇 종류의 작은 DNA 바이러스를 제외한 대부분의 바이러스는 게놈 복제를 위한 자신의 핵산중합효소를 유전자로 암호화하고 있다. 바이러스 핵산중합효소에는 DNA-의존DNA 중합효수, RNA-의존RNA 중합효소, RNA-의존 DNA 중합효소 세 종류가 있으며, 이들은 모두 4개의 공통된 모티프(motif)를 가진다. 우리는 볼티모어의 분류체계와 바이러스의 핵산중합효소와의 관계를 아미노산 서열을 통해 분자 계통분류학적 분석을 통해 알아보고자 하였다. NCBI GenBank에서 얻은 바이러스 중합효소의 아미노산 서열을 CLUSTAL X 프로그램으로 다중서열하고, Neighbor-joining, Maximum-likelihood, Bayesian의 세 가지 방법으로 계통도를 그려보았다. 미세한 차이는 있었으나, 세 가지 방법 모두에서 볼티모어의 분류법과 일치하는 결과를 보였고, 특이하게도 두 가닥 RNA 바이러스는 숙주의 종류에 따라, (-)RNA 바이러스는 게놈의 절편화에 따라 각각2개의 소집단으로 나뉘어지는 것을 볼 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제16권7호
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• pp.1017-1025
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• 2006

Hantaviruses possess three RNA segments of negative sense. Co-infection of closely related hantaviruses may result in generation of a progeny virus with genomic polyploidy, containing a partial or complete set of genome originated from more than one parental virus. To characterize the formation of viral genomic polyploidy, cultured Vero-E6 cells were co-infected with two closely related hantaviruses, Hantaan and Maaji, and the progeny viruses examined. The genotype of plaque-purified viruses was analyzed by a virus-specific RT-PCR. Seventy percent (67/96) of the progeny virus was categorized as Hantaan and 3.3% (2/96) was classified as Maaji, whereas 20% (21/96) was considered polyploidy as they contained both types of the S RNA segment. Most of the polyploidy progeny viruses were unstable and gave rise to either one of the parental viruses or a reassortant after several rounds of plaque purification. No recombination between the heterologous pair of S RNA was observed for those polyploid viruses during three consecutive plaque-to-plaque passages. These data suggest that the viral polyploidy formation constitutes a primary mechanism underlying the generation of a newly emerged hantavirus.

• The Plant Pathology Journal
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• 제38권3호
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• pp.220-228
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• 2022

Pollen is a vector for viral transmission. Pollenmediated viruses cause serious economic losses in the fruit industry. Despite the commercial importance of pollen-associated viruses, the diversity of such viruses is yet to be fully explored. In this study, we performed metatranscriptomic analyses using RNA sequencing to investigate the viral diversity in imported apple and kiwifruit pollen. We identified 665 virus-associated contigs, which corresponded to four different virus species. We identified one virus, the apple stem grooving virus, from pear pollen and three viruses, including citrus leaf blotch virus, cucumber mosaic virus, and lychnis mottle virus in kiwifruit pollen. The assembled viral genome sequences were analyzed to determine phylogenetic relationships. These findings will expand our knowledge of the virosphere in fruit pollen and lead to appropriate management of international pollen trade. However, the pathogenic mechanisms of pollen-associated viruses in fruit trees should be further investigated.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 1999년도 학술발표회 진행표 및 논문초록
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• pp.37-37
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• 1999

The influenza A viruses which are the most severe and common among the influenza viruses have 8 segmented RNA genomes Each RNA segment has highly conserved 3' and 5' terminal sequence except a single U\longrightarrowC variation especially in the 4 position of the 3' terminal of the 3 segments encoding own RNA polymerase.(omitted)