• The Plant Pathology Journal
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• 제38권4호
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• pp.417-422
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• 2022

Apple stem grooving virus (ASGV) is a destructive viral pathogen of pome fruit trees that causes significant losses to fruit production worldwide. Obtaining ASGV-free propagation materials is essential to reduce economic losses, and accurate and sensitive detection methods to screen ASGV-free plantlets during in vitro propagation are urgently necessary. In this study, ASGV was sensitively and accurately quantified from in vitro propagated apple plantlets using a reverse transcription droplet digital polymerase chain reaction (RT-ddPCR) assay. The optimized RT-ddPCR assay was specific to other apple viruses, and was at least 10-times more sensitive than RT-real-time quantitative PCR assay. Furthermore, the optimized RT-ddPCR assay was validated for the detection and quantification of ASGV using micropropagated apple plantlet samples. This RT-ddPCR assay can be utilized for the accurate quantitative detection of ASGV infection in ASGV-free certification programs, and can thus contribute to the production of ASGV-free apple trees.

• 식물병연구
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• 제29권2호
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• pp.193-199
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• 2023

The apple stem grooving virus (ASGV) is one of the most harmful latent viruses infecting pear orchards worldwide. To examine the genetic diversity of ASGV in Korean pear orchards, the complete coat protein (CP) gene of five ASGV isolates collected from various regions were identified. The five Korean ASGV isolates showed 88-96% nucleotide identity with the 11 isolates worldwide occurring elsewhere in the world. Phylogenetic analysis of five isolates, as well as the previously sequenced isolates, indicated that the ASGV clusters had no correlation with the host or geographical regions of origin. Recombination analysis showed that one of the five Korean isolates is a recombinant, with a recombination site in the CP gene region (nt 532-708). This study is the first report of natural recombination within the CP gene of ASGV isolates from pears grown in Korea.

• The Plant Pathology Journal
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• 제22권3호
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• pp.260-264
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• 2006

Talaromyces flavus mediates the transmission of Apple stem grooving virus (ASGV) to several host plants. The ASGV-F carried by T.flavus was partially purified from the fungus. Based on sequence analysis and homology searches, this is closely related to other ASGV strains isolated from host plants. The partially purified viral coat protein (CP) was separated on a 12% SDS-polyacrylamide gel and analyzed by Western blotting with an ASGV anti-serum. A single band at 28 kDa reacted with the ASGV anti-serum. The deduced amino acid sequence of the ORF-l showed conserved domains, including an NTP-binding helicase motif, GFAGSGKT. The amino acid sequences of the helicase and CP showed strong homology to other ASGV strains (98%). All ASGV isolated from plants and fungi had salt bridges composed of the CP and the GFAGSGKT motif of the helicase, which are commonly conserved in plant viruses. These results suggest that ASGV-F is one of ASGV strains isolated from T.flavus based on sequence similarity as well as the serological analysis of CP.

• 식물병연구
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• 제16권3호
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• pp.326-330
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• 2010

2009년 가을, 배 주산단지인 나주, 울산, 안성의 3개 지역에서 신고, 원황, 추황 품종을 대상으로 배 바이러스병 발생률을 ELISA와 RT-PCR로 조사한 결과 ELISA 검정은 ACLSV, ASPV, ASGV 3종 바이러스가 검출되어 35.2%의 발생률을 보였다. RT-PCR 검정은 ELISA 검정 보다는 적은 시료로 검정을 수행하였지만 ACLSV, ASPV, ASGV 3종 바이러스가 검출되었고 86.3%의 높은 발생률을 보였다. ELISA와 RT-PCR 진단 모두 ASGV > ASPV > ACLSV 순으로 ASGV의 발생률이 높게 나타났지만 발생률에는 ELISA 22.1%, RT-PCR 74.2%로 큰 차이가 있었다. 따라서 배 바이러스 검정은 ELISA 방법 보다 RT-PCR 방법이 바이러스 검출에 적합하다. ASGV가 감염된 신고 잎에서는 부정형의 검은점 증상이 보였으며 ASPV와 ACLSV가 감염된 식물체에서는 별다른 이상증상은 보이지 않았다. RT-PCR로 증폭된 ACLSV, ASPV, ASGV 유전자는 기존에 보고된 바이러스와 83~94%의 상동을 보였고, 특히, ASPV는 국내에서 처음으로 발생이 확인되었다.

• The Plant Pathology Journal
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• 제22권2호
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• pp.168-173
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• 2006

To develop the diagnostic method for the viral infection in apple, the partial genes corresponding to the N-terminal region of RNA polymerase of Apple stem grooving virus (ASGV) and coat protein of Apple chlorotic leaf spot virus (ACLSV) were characterized from the infected apple cultivars in Korea. Based on the nucleotide sequences of the characterized partial genes, the virus gene-specific primers were designed for the detection of ASGV and ACLSV infected in species of Malus. The RT-PCR using the primers for the genes of ASGV and ACLSV successfully gave rise to 404 and 566 bp DNA fragments, respectively. Using those viral gene-specific primers, the multiplex RT-PCR assays were also established to diagnose the mixed infection by ASGV and ACLSV simultaneously. Furthermore, the control primers, which have to be included for the RT-PCR as an internal control, were designed using the nucleotide sequence of the gene encoding elongation factor $1{\alpha}(EF1{\alpha})$. This multiplex RT-PCR including the control primers provides more reliable, rapid and sensitive assay for the detection of ASGV and ACLSV infected in Korean apple cultivars.

• 식물병연구
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• 제28권2호
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• pp.92-97
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• 2022

Apple stem grooving virus (ASGV) is a high-risk viral pathogen that infects many types of fruit trees, especially pear and apple, and causes serious economic losses across the globe. Thus, rapid and reliable detection assay is needed to identify ASGV infection and prevent its spread. A reliable reverse transcription loop-mediated isothermal amplification (RT-LAMP) was developed, optimize, and evaluated for the coding region of coat protein of ASGV in pear leaf. The developed RT-LAMP facilitated the simple screening of ASGV using visible fluorescence and electrophoresis. The optimized reaction conditions for the RT-LAMP were 63℃ for 50 min, and the results showed high specificity and 100-fold greater sensitivity than the reverse transcription polymerase chain reaction. In addition, the reliability of the RT-LAMP was validated using field-collected pear leaves. Furthermore, the potential application of paper-based RNA isolation, combined with RT-LAMP, was also evaluated for detecting ASGV from field-collected samples. These assays could be widely applied to ASGV detection in field conditions and to virus-free certification programs.

• 식물병연구
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• 제23권4호
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• pp.355-362
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• 2017

국내에서 유통되고 있는 사과나무 묘목의 바이러스 감염 실태를 파악하기 위하여 사과 '홍로'와 '후지' 및 '후지' 아조변이 품종을 구입하여 5종류의 바이러스에 대한 감염 여부를 검정하였다. 그 결과, '홍로' 품종의 접수 부위는 ACLSV, ASPV 및 ASGV에 각각 100%, 81.3% 및 100%의 감염률을 보였고 ApMV와 ASSVd에는 전혀 감염되지 않았다. '홍로' 품종의 대목 부위에 대하여, ACLSV, ASPV 및 ASGV의 감염률은 각각 87.5%, 81.3% 및 100%이었고 ApMV와 ASSVd의 감염률은 각각 12.5% 및 6.3%이었다. '후지' 품종 및 '후지' 아조변이 품종의 접수 부위는 ACLSV, ASPV 및 ASGV에 각각 86.7%, 86.7% 및 100%의 감염률을 보였고 ApMV와 ASSVd에는 전혀 감염되지 않았다. 대목 부위는 ACLSV, ASPV 및 ASGV에 각각 86.7%, 93.3% 및 93.3%의 감염률을 보였고 ApMV와 ASSVd에 대한 감염률은 각각 12.5%와 6.3%이었다.

• The Plant Pathology Journal
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• 제22권3호
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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.

• 식물병연구
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• 제25권1호
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• pp.43-47
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• 2019

Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV), Apple stem grooving virus (ASGV), and Apple scar skin viroid (ASSVd) are economically important viruses that infect pear tree species worldwide. To evaluate the prevalence of these viruses in Korea, we investigated infection degree of three viruses and one viroid for the commercial nursery trees of the pear cultivars, Niitaka, Chuwhang, Wonwhang, and Whasan in 2017 and 2018. The results showed that the infection ratio of ACLSV, ASPV, ASGV, and ASSVd for the scion of pear cultivar Niitaka was 10%, 45%, 77%, and 50%, respectively. From the scion of pear cultivar Chuwhang, infection ratios of ASPV, ASGV, and ASSVd were found to be 70%, 50%, and 60%, respectively. From the scion of pear cultivar Whasan, infection ratios of ACLSV, ASPV, ASGV and ASSVd were found to be 40%, 60%, 93%, and 20%, respectively. From the root stock of pear cultivar Wonwhang, infection ratios of ACLSV, ASPV, ASGV, and ASSVd showed 28%, 57%, 100%, and 14%, respectively. ASGV had the highest recorded infection rate, and ACLSV was characterized by the lowest infection rate. The mixed infection ratio of Niitaka, Chuwhang, Whasan, and Wonwhang was 45%, 60%, 70%, and 85%, respectively.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.122-123
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• 2003

Apple stem grooving virus (ASGV) belongs to Capillovirus and infects pome fruits. Transmission mode of ASGV is known by grafting and mechanical inoculation into susceptible hosts, not by any other natural vectors. But we have observed the spread of ASGV in the field without mechanical inoculation or grafting. Transmission seems to be occurred from tree-to-tree and tree-to-susceptible herbaceous plants along but not across ditches in the field. In order to ascertain this possibility, various fungi were isolated and cultured from ASGV-infected plants and 69 isolates were characterized. By means of RNA dot-blot hybridization and PCR analysis, 3 isolates were sorted out for further studies. The isolates were identified to Tataromyces sp. and belonged to Phenicillium by morphological characteristics and molecular markers. As an experimental host, 10 kidney beans (Phaseolus vulgaris) were screened and Kyunggi-5 was selected for virus amplification and symptom development. Kyunggj-5 infected by fungi which seemed to carry ASGV showed the typical disease symptoms and viral coat protein genes were detected from all tested plants. To confirm the Koch's rule, fungi cultured from inoculation origins of kidney bean were grown on PDA media and re-inoculated to hosts. The fungi isolated from inoculation origins induced the typical disease symptoms on hosts. However virus free fungi did not induce any symptom on the experimental hosts. This bioassay showed that these typical symptoms were caused by virus, not fungi.