• 식물병연구
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• 제16권3호
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• pp.247-253
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• 2010

우리나라 사과 및 배 주산단지 12개 지역을 대상으로 ASSVd에 대한 진단 결과, 사과 및 배나무 전체 1,193주에서 20주가 바이로이드가 검출되어 1.7%의 이병율을 나타내었다. 품종별 감염상황을 살펴본 결과, 사과는 '홍로' 품종이 이병율이 3.6%로 타 품종에 비해 많이 감염되어 있음을 알 수 있었다. 국내에서 확인된 후지 등 주요 품종에서의 ASSVd 병징은 주로 과피 얼룩반점 증상이었으나, 후지품종 과피에 발생한 코르크(corking) 반점증상이 ASSVd 감염과 연관된 것으로 새롭게 확인하였다. 본 증상은 앞으로 유관으로 바이로이드 감염여부를 판단하는 중요한 지표가 될 것으로 판단된다. ASSVd에 감염된 사과를 대상으로 real time RT-PCR을 이용하여 ASSVd을 진단하고 시료간 상대 정량값을 분석하였다. real time RTPCR은 기존 RT-PCR에 비하여 전기영동이 필요없이 신속하고 간편하게 해석할 수 있으며, 오염의 위험성이 적었다. 특히 시료 간에 상대적인 정량값을 알 수 있기 때문에 시료를 비교 분석하는데 유효하다.

• The Plant Pathology Journal
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• 제22권1호
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• pp.63-67
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• 2006

Apple scar skin, one of the most destructive diseases affecting apple, is caused by Apple scar skin viroid (ASSV d). Fruit dappling appeared on several cultivars in Korea and has been distributed to major cultivated areas since 2001. ASSVd was identified from infected fruits by using nucleic acid sequence-based amplification with electrochemiluminescence (NASBA-ECL). NASBA-ECL method was faster and hundredfold more sensitive than reverse transcription-polymerase chain reaction (RT-PCR) for ASSVd detection in apple leaves/ stems. ASSVd was rapidly transmitted to the entire tree in the second year after artificial inoculation. The ASSVd could be transmitted efficiently by using contaminated pruning scissors to both lignified stems (60 to $70\%$) and green shoots (20 to $40\%$) of apple tree and young plants. Dipping of contaminated scissors in $2\%$ sodium hypochlorite solution effectively prevented viroid transmission. In the ASSV d-infected fruits, the viroid was easily detected from fruit skin, seed coat, and embryo. Moreover, embryo and endosperm separately excised from the ASSVd-infected seeds were ASSVd positive in NASBA-ECL assay. Seedlings germinated from ASSVd-positive seeds showed $7.7\%$ infection rate., which indicated that ASSVd is seed-borne.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.143.2-143
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• 2003

A rapid and sensitive assay for the specific detection of plant viroids using reverse transcription-polymerase chain reaction(RT-PCR) has been developed already. The nested RT-PCR assay cloud be applied for the detection of apple scar skin viroid(ASSVd) from young leaves and other tissues. ASSVd has central conserved region(CCR), terminal left(T$\sub$L/) and terminal right(T$\sub$R/) domain. Primers were designed from these regions. Primer sets were successfully applicable for the amplification of full length or partial region of ASSVd by nested RT-PCR. Nested RT-PCR assay was more sensitive and accurate method to detect ASSVd from young trees during the early time of apple cultivation.

• The Plant Pathology Journal
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• 제35권2호
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• pp.164-171
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• 2019

An assay for detecting Apple scar skin viroid (ASSVd) was developed based on nucleic acid sequence based amplification (NASBA) in combination with realtime detection during the amplification process using molecular beacon. The ASSVd specific primers for amplification of the viroid RNA and molecular beacon for detecting the viroid were designed based on highly conserved regions of several ASSVd sequences including Korean isolate. The assay had a detection range of $1{\times}10^4$ to $1{\times}10^{12}$ ASSVd RNA $copies/{\mu}l$ with reproducibility and precision. Following the construction of standard curves based on time to positive (TTP) value for the serial dilutions ranging from $1{\times}10^7$ to $1{\times}10^{12}$ copies of the recombinant plasmid, a standard regression line was constructed by plotting the TTP values versus the logarithm of the starting ASSVd RNA copy number of 10-fold dilutions each. Compared to the established RT-PCR methods, our method was more sensitive for detecting ASSVd. The real-time quantitative NASBA method will be fast, sensitive, and reliable for routine diagnosis and selection of viroid-free stock materials. Furthermore, real-time quantitative NASBA may be especially useful for detecting low levels in apple trees with early viroid-infection stage and for monitoring the influence on tree growth.

• 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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• 제18권6호
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• pp.342-344
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• 2002

Apple scar skin viroid (ASSVd) has been one of the most destructive diseases in Korean apple orchards. Symptoms of the scar skin viroid disease were detected in various apple cultivars, namely, Sansa, Fuji, Chukwang, Miki-Life, Hongro, and Songbongeum cultivated in the southern part of Korea. The RNA molecules were extracted from the apples bearing dapple apple symptoms with the application of CF-11 RNA extraction method. The purified RNAs were used for the synthesis of cDNA with RT-PCR. The PCR products were cloned and sequenced. The viroid RNA molecules from the six different cultivars bearing the dapple symptos showed the same nucleotide sequences as that of the Korean strain of ASSVd（ASSVd-K). ASSVd-K was detected from apple orchards in Kunwi, Sangju, Uiseong, Yeong-yang, Andong, and Youngduk in Gyeongbuk Province in 2001, and in Muju in Jeonbuk Province in 2002. As the viroid disease could be propagated vegetatively, it can be widely transmitted gradually in Korea.

• The Plant Pathology Journal
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• 제17권5호
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• pp.300-304
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• 2001

Apple is the most economically important fruit in Korea. The suspected viroid disease of dapple apple was found in apple fruits cultivated in Kyungpook province. Symptoms begin in mid-July as small circular spots, which stand out against the background color on the young fruit. Dappling of the fruit becomes more intense and easier to detect as the fruit approaches maturity; the affected spots remain yellowish as the fruit matures. no leaf or bark syndromes have been associated with this disease. The infected fruits are downgraded considerably during quality grading. The low molecular weight RNA containing viroid RNA molecules were extracted from the peels of the apples with dapple symptoms. The RNA molecules were extracted from the apples using Qiagen column chromatography. The purified RNAs were used for the synthesis of cDNA with RT-PCR. The PCR products were then ligated into a pGEM-T Easy vector, cloned and sequenced. The sequence of the viroid RNA molecule shows 331 nucleotides with one base difference ("G" insertion between the position of 133 and 134) compared with that of the Apple scar skin viroid (ASSVd) reported by Hashimoto and Koganezawa in Japan. This is the first report on the occurrence of the ASSVd in apple trees cultivated in Korea, as well as the identification of a new Korean strain of the ASSVd.the ASSVd.

• 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.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권6호
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• pp.2634-2648
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• 2020

In this paper, an adaptive sparse singular value decomposition (ASSVD) algorithm is proposed to estimate the signal matrix when only one data matrix is observed and there is high dimensional white noise, in which we assume that the signal matrix is low-rank and has sparse singular vectors, i.e. it is a simultaneously low-rank and sparse matrix. It is a structured matrix since the non-zero entries are confined on some small blocks. The proposed algorithm estimates the singular values and vectors separable by exploring the structure of singular vectors, in which the recent developments in Random Matrix Theory known as anisotropic Marchenko-Pastur law are used. And then we prove that when the signal is strong in the sense that the signal to noise ratio is above some threshold, our estimator is consistent and outperforms over many state-of-the-art algorithms. Moreover, our estimator is adaptive to the data set and does not require the variance of the noise to be known or estimated. Numerical simulations indicate that ASSVD still works well when the signal matrix is not very sparse.

• 식물병연구
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• 제27권2호
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• pp.79-83
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• 2021

The aim of the present study was to develop a sensitive and specific detection method for the rapid detection of apple scar skin viroid (ASSVd) in apple leaves. The resulting reverse transcription recombinase polymerase amplification (RT-RPA) assay can be completed in 10 min at 42℃, is 10 times more sensitive than conventional reverse transcription polymerase chain reaction, and can specifically amplify ASSVd without any cross-reactivity with other common apple viruses, including apple stem grooving virus, apple stem pitting virus, and apple chlorotic leaf spot virus. The reliability of the RT-RPA assay was assessed, and the findings suggested that it can be successfully utilized to detect ASSVd in field-collected samples. The RT-RPA assay developed in the present study provides a potentially valuable means for improving the detection of ASSVd in viroid-free certification programs, especially in resource-limited conditions.