• 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.

• 농업과학연구
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• 제43권1호
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• pp.21-27
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• 2016

Apple stem grooving virus (ASGV), Apple chlorotic leaf spot virus (ACLSV), and Apple stem pitting virus (ASPV) have been known to induce top working disease causing economical damage in apple. Occurrences of these three viruses in pome fruit trees, including apple, have been reported around the world. The transmission of the three viruses was reported by grafting, and there was no report of transmission through mechanical contact, insect vector, or seed except some herbaceous hosts of ASGV. As RNA extraction methods for fruit trees, Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) and multiplex RT-PCR techniques have been improved for reliability and stability, and low titer viruses that could not be detected in the past have become detectable. We studied the seed transmission ability of three apple viruses through apple seedling diagnosis using RT-PCR. Nineteen seeds obtained from commercially grown apple were germinated and two of the resulting plants were ASGV positive. Seven clones of the amplified ASGV coat protein (CP) genes of these isolates were sequenced. Overall sequence identities were 99.84% (nucleotide) and 99.76% (amino acid). Presence of a previously unreported single nucleotide and amino acid variation conserved in all of these clones suggests a possible association with seed transmission of these 'S' isolates. A phylogenetic tree constructed using ASGV CP nucleotide sequences showed that isolate S sequences were grouped with Korean, Chinese, Indian isolates from apple and Indian isolates from kiwi.

• Journal of Plant Biotechnology
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• 제49권3호
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• pp.222-229
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• 2022

사과는 국내 과수산업에서 가장 많이 재배되고 있는 과종이다. 하지만 apple mosaic virus (ApMV), apple stem grooving capillovirus (ASGV), apple stem pitting virus (ASPV), apple chlorotic leaf spot virus (ACLSV), apple scar skin viroid (ASSVd)와 같은 바이러스 및 바이로이드에 감염되면 과실의 수확량 감소 및 품질 저하를 야기시킨다. 본 연구에서는 국내 사과 농가에서 가장 많이 감염되어 있는 ASGV 바이러스를 제거하기 위한 효율적인 무병화 시스템을 확립하고자 하였다. ASGV에 감염된 폿트묘를 36℃, 38℃, 40℃가 유지되는 항온·항습장치에서 4주간 열처리를 수행하였으며, 신초 생장율과 바이러스 제거율을 조사하였다. 신초 생장률은 36℃ 처리구에서 가장 높았으며 신초의 중간부와 상단부는 바이러스가 제거되었으나 하단부는 바이러스가 제거되지 않았다. 38℃, 40℃ 처리구는 신초의 모든 구간에서 바이러스가 제거되지 않았으며, 40℃ 처리구는 신초의 생장 없이 열처리 3주 후 고사되었다. 36℃ 온도에서 열처리된 폿트묘의 경정을 절취하여 기외에서 접목하였으며 94%의 생존율과 20%의 바이러스 제거율을 보였다. 따라서 열처리 및 경정접목을 통해 무병묘 생산이 가능할 것으로 판단되었다.

• 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.

• 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.

• The Plant Pathology Journal
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• 제34권6호
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• pp.575-579
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• 2018

Apple stem grooving virus (ASGV) is considered to cause the most economically important viral disease in pears in Korea. The current PCR-based methods used to diagnose ASGV are time-consuming in terms of target detection. In this study, a novel assay for specific ASGV detection that is based on reverse transcription-recombinase polymerase amplification is described. This assay has been shown to be reproducible and able to detect as little as $4.7ng/{\mu}l$ of purified RNA obtained from an ASGV-infected plant. The major advantage of this assay is that the reaction for the target virus is completed in 1 min, and amplification only requires an incubation temperature of $42^{\circ}C$. This assay is a promising alternative method for pear breeding programs or virus-free certification laboratories.

• 식물병연구
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• 제26권2호
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• pp.95-102
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• 2020

사과 바이러스 4종(Apple chlorotic leaf spot virus [ACLSV], Apple stem pitting virus [ASPV], Apple stem grooving virus [ASGV], Apple mosaic virus [ApMV]), 바이로이드 1종(Apple scar skin viroid [ASSVd])을 대상으로 국내 감염률을 조사한 결과, 감염률은 97.3%로 대부분의 사과나무가 바이러스 및 바이로이드에 감염되어 있는 것으로 조사되었다. 지역별로는 정선 98.8%, 단양 100%, 예산 100%, 장수 89.1%, 무주 98.1%였으며, 바이러스 및 바이로이드 각각의 감염률은 ASGV 93.4%, ASPV 85.7%, ACLSV 59.0%, ASSVd 6.7%, ApMV 3.6% 순으로 ASGV의 감염률이 가장 높았고 ApMV의 감염률이 가장 낮은 것으로 조사되었다. 또한, 바이러스 및 바이로이드 2종 이상 복합 감염비율은 84.8%로 단 1종만 감염된 비율인 12.4%와 비교하여 약 7배 가까이 되는 것으로 조사되었다.

• Journal of Plant Biotechnology
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• 제44권4호
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• pp.379-387
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• 2017

Apple scar skin viroid (ASSVd), Apple chlorotic leaf spot virus(ACLSV), Apple stem pitting virus (ASPV), Apple stem grooving virus (ASGV)는 사과를 감염시키는 대표적인 바이러스로, 이러한 4종 바이러스에 복합 감염된 사과 '홍로'의 동절기 가지의 휴면아(측아)로부터 다양한 크기 (0.4 mm ~ 1.2 mm)와 발달단계 (이하 Stage 1, Stage 2, Stage 3라 칭함)의 경정 및 측부 분열조직을 절취하여 BA 3.0 mg/L 와 IBA 0.1 mg/L가 혼합된 배지에 배양하여 캘러스를 형성시킨 후, 감염 바이러스바이러스의 제거유무를 조사하였다. 직경 10 mm이상 증식된 캘러스 31 계통을 RT-PCR 분석으로 제거효율을 알아 본 결과, ACLSV는 100%, ASSVd와 ASPV는 93.5%의 높은 제거 효율을 보인 반면, ASGV는 25.8%로 상대적으로 제거효율이 낮았다. 4종 바이러스가 동시에 모두 제거되는 경우는 Stage 1의 휴면아의 분열조직을 배양하였을 때만 가능하였는데, 그 이유는 ASGV가 이 시기의 배양에서 주로 제거되었기 때문으로, ASGV는 다른 바이러스와는 달리 분열조직의 발달단계가 큰 영향을 미치는 것으로 나타났다. 휴면아의 분열조직을 배양하여 바이러스를 제거한 예는 세계적으로 보고된 바가 없는 것으로서, 본 연구결과는 향 후 사과의 무병묘 생산에 매우 유용한 자료로 활용될 것이다.

• 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.