• Research in Plant Disease
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• v.10 no.2
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• pp.145-149
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• 2004

'Hongro' is one of the most important apple cultivars whose growing area is increasing because of its good quality. Recently fruit shrinking symptom causing decrease of fruit size, juice, and quality, appears in some commercial 'Hongro' orchards. The average frequency of occurrence of fruit shrinking symptom was 12 % of total trees investigated and Apple chlorotic leaf spot virus (ACLSV) was detected from all the trees showing fruit shrinking symptom by ELISA. A typical virus infection symptom of leaf epinasty and stem necrosis appeared on woody indicators, Spy227 and Virginia crab grafted with infected trees and all the grafted trees showed positive reaction to ACLSV antiserum by ELISA. It was proved that ACLSV can be easily transmitted by grafting. ACLSV was also isolated from the leaves of C. quinoa inoculated with sprouting leaf sap of infected trees. To prove that the fruit shrinking symptom was caused by ACLSV infection, ACLSV-infected scion was grafted on virus-free 'Hongro/M9' and the fruit characteristics were investigated. Consequently the same symptoms of fruit size and juice decreasing were observed from the trees grafted with ACLSV-infected scion. Therefore, it is suggested that the fruit shrinking symptom is caused by ACLSV infection and 'Hongro' can be classified as sensitive cultivar to ACLSV.

• Research in Plant Disease
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• v.18 no.4
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• pp.391-395
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• 2012

To investigate the occurrence of viruses in peach, leaf samples were collected from peach trees in commercial orchard of six areas in Korea. Reverse transcription polymerase chain reaction (RT-PCR) was used to identify the presence of the following stone fruit viruses: Apple chlorotic leaf spot virus (ACLSV), Apple mosaic virus (ApMV), Prune dwarf virus (PDV), Prunus necrotic ringspot virus (PNRSV) and Plum pox virus (PPV). About 65.0% of the 515 samples were infected with ACLSV and PNRSV. Virus-like symptoms showing mosaic on leaves was observed in ACLSV infected peach trees. However, PNRSV infected peach trees showed no symptoms. These viral DNAs by sequence analysis were confirmed 4 ACLSV isolates and 3 PNRSV isolates. The Korean peach isolates of ACLSV and PNRSV showed 70-99% and 88-99% amino acid sequence identities, respectively, with those reported previously and their amino acid sequence identities with each other were approximately 95% and 88%, respectively. Phylogenetic analysis indicated that the Korean ACLSV isolates belong to the A group of ACLSV. The Korean PNRSV isolates reported in this study were grouped into I (PV32), II (PV96) and III (PE5) groups.

• The Plant Pathology Journal
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• v.22 no.2
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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.

• Research in Plant Disease
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• v.16 no.3
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• pp.326-330
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• 2010

Three pome fruit viruses, Apple chlorotic leaf spot virus (ACLSV), Apple stem grooving virus (ASPV) and Apple stem pitting virus (ASGV) were detected in pear trees (Pyrus pyrifolia) using double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) in Ansung, Naju and Ulsan provinces of Korea. Infection rate of three viruses was 35.2% from 452 leaf samples of the three cultivars of pear trees. Also, each of three viruses was detected by reverse transcription polymerase chain reaction (RT-PCR) for a limited number of samples. Infection rate of three viruses was 86.3% from 233 leaf samples of the three pear cultivars. The virus infection rates by RT-PCR were much higher than ELISA. ASGV was prevailing on pear with 74.2%, whereas ASPV and ACLSV were found in 34.8% and 0.4% of tested samples, respectively. Symptoms caused by ASGV showed black spots of infected Niitaka cultivar leaves. The ACLSV, ASPV and ASGV isolates showed 83~94% sequence identity at a nucleotide level to other pome fruit virus isolates when analyzed by NCBI BLAST. Pome fruit viruses occurring in pear were ACLSV, ASPV and ASGV. This is the first report of pear trees infected ASPV in Korea.

• Research in Plant Disease
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• v.23 no.4
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• pp.355-362
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• 2017

The 4 viruses, the Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV), Apple stem grooving virus (ASGV), and Apple mosaic virus (ApMV) and 1 viroid, Apple scar skin viroid (ASSVd) are known major viral pathogens of apple trees in Korea. Infection degree of the 5 viral pathogens in the commercial nursery trees of major apple cultivars, 'Hongro', 'Fuji' and bud mutation of 'Fuji' was investigated. Infection ratio of the ACLSV, ASPV and ASGV for scion of an apple cultivar 'Hongro' were 100%, 81.3% and 100%, respectively. On the other hand, no infection for either ApMV and ASSVd detected. For the root stock of the cultivar, infection ratio of ACLSV, ASPV and ASGV showed 87.5%, 81.3% and 100% as well as ApMV and ASSVd were 12.5% and 6.3%, respectively. From the scion of apple cultivars 'Fuji' and bud mutation of 'Fuji', infection ratio of ACLSV, ASPV and ASGV showed 86.7%, 86.7% and 100%, respectively. Whereas, no infection for either ApMV or ASSVd detected. From the root stock of the cultivars, infection ratio of ACLSV, ASPV and ASGV showed 86.7%, 93.3% and 93.3% as well as ApMV and ASSVd were 12.5% and 6.3%, respectively. Result of our study indicates that most of commercial nursery apple trees were supplied with multiple infections by apple viruses causing potential losses for apple growers and, henceforth, agricultural policy for supply of the virus-free trees should be employed as soon as possible.

• Research in Plant Disease
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• v.25 no.1
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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.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.52-52
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• 2018

Apple (Malus domestica) is one of the most economically important fruits in Korea. But virus infection has decreased sustainable production of apple and caused the serious problems such as yield loss and poor fruit quality. Virus or viroid infection including Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV), Apple stem grooving virus (ASGV), Apple mosaic virus (ApMV) and Apple scar skin viroid (ASSVd) has been also reported in Korea, furthermore, its damages and economic losses have increased constantly. In our research, we tried to survey virus infection for commercial nursery trees of major apple cultivars, especially dwarfing rootstocks 'M.9' and 'M.26' as well as scions. Trees were collected from 11 locations which have produced a great amount of apple nursery stocks in Korea. Infection degree was investigated in apple cultivars, 'Hongro' and 'Fuji' using RT-PCR method. In the scion of cultivar 'Hongro', infection ratio of ACLSV, ASPV and ASGV were 100%, 81.8% and 100% respectively. In the rootstock of cultivar 'Hongro', infection ratio of ACLSV, ASPV, ASGV and ApMV were 90.9%, 81.8%, 100% and 9.1% respectively. In the scion of cultivar 'Fuji', infection ratio of ACLSV, ASPV and ASGV were 81.8%, 90.9% and 100% respectively. In the rootstock of cultivar 'Fuji', infection ratio of ACLSV, ASPV, ASGV and ApMV were 81.8%, 90.9%, 100% and 9.1% respectively. Infection of ASSVd was not detected in both cultivars. From our results, it was found that most of apple rootstocks and scions had multiple infections by apple viruses which have caused economic damage in fruit production.

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.379-387
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• 2017

Various sizes (0.2 ~ 1.2 mm) and developmental stages (referred to as Stage 1 ~ 3) of apical and lateral meristems were excised, together or separately, directly from dormant buds of apple 'Hongro'. They were mixed infected by Apple scar skin viroid (ASSVd), Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV) and Apple stem grooving virus (ASGV), which are major viruses attacking apples. A total of 31 callus lines (> 10 mm in diameter) were obtained by culturing the explants on Murashige and Skoog (MS) medium supplemented with 3% sucrose, 3.0 mg/L benzyladenine (BA) and 0.1 mg/L indole-3-butyric acid (IBA), and they were subjected to RT-PCR analysis for virus detection. A high rate of virus elimination (expressed as the percentage of calli that did not amplify during RT-PCR, i.e., RT-PCR negative calli per total number of calli obtained) was achieved for ACLSV (100%), ASSVd (93.7%), and ASPV (93.7%), whereas it was only 25.8% for ASGV. ASPV was detected in the presence of 2 ~ 3 bracts. Simultaneous virus elimination of ASSVd, ASPV, ACLSV, and ASGV occurred during the meristem culture, in which the early stages of the dormant buds (Stage 1) were used, because ASGV was mostly eliminated during that stage. The results of the present study will be valuable for the production of virus-free apple trees.

• Research in Plant Disease
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• v.19 no.4
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• pp.326-330
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• 2013

During the 2012 growing season, 154 leaf samples were collected from sweet cherry trees in Hwaseong, Pyeongtaek, Gyeongju, Kimcheon, Daegu, Yeongju and Eumseong and tested for the presence of Cherry green ring mottle virus (CGRMV). PCR products of the expected size (807 bp) were obtained from 6 samples. The PCR products were cloned and sequenced. The nucleotide sequences of the clones showed over 88% identities to published coat protein sequences of CGRMV isolates in the GenBank database. The sequences of CGRMV isolates, CGR-KO 1-6 shared 98.8 to 99.8% nucleotide and 99.6 to 100% amino acid similarities. Phylogenetic analysis indicated that the Korean CGRMV isolates belong to the group II of CGRMV coat protein genes. The CGRMV infected sweet cherry trees were also tested for Apple chlorotic leaf spot virus (ACLSV), Apple mosaic virus (ApMV), Cherry necrotic rusty mottle virus (CNRMV), Cherry mottle leaf virus (CMLV), Cherry rasp leaf virus (CRLV), Cherry leafroll virus (CLRV), Cherry virus A (CVA), Little cherry virus 1 (LChV1), Prune dwarf virus (PDV) and Prunus necrotic ringspot virus (PNRSV) by RT-PCR. All of the tested trees were also infected with ACLSV.

• Research in Plant Disease
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• v.26 no.2
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• pp.95-102
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• 2020

The investigation of the infection rate of domestic apple orchards by four types of apple viruses (Apple chlorotic leaf spot virus [ACLSV], Apple stem pitting virus [ASPV], Apple stem grooving virus [ASGV], Apple mosaic virus [ApMV]) and one type of viroid (Apple scar skin viroid, ASSVd) found that most apple trees were infected with viruses and viroid at the rate of 97.3%. By region, the infection rate in Jeongseon stood at 98.8%, Danyang at 100%, Yesan at 100%, Jangsu at 89.1%, and Muju at 98.1%. By each virus and viroid, the infection rate of ASGV was the highest at 93.4%, followed by ASPV at 85.7%, ACLSV at 59.0%, ASSVd at 6.7%, and ApMV at the lowest 3.6%. In addition, 84.8% of the cases were infected with two or more types of viruses and viroid, nearly seven times the single type infection rate of 12.4%, and the cases infected with three viruses, ASPV, ACLSV, and ASGV accounted for 56.2%, more than the half the total number of trees investigated.