• The Korean Journal of Mycology
• /
• v.51 no.3
• /
• pp.179-190
• /
• 2023

Grapevine downy mildew, caused by Plasmopara viticola, significantly damages vineyards and is one of the most devastating diseases affecting cultivated grapes worldwide. In this study, we characterized the phenotypic and molecular traits of 11 P. viticola isolates from four grape-growing regions in South Korea. Additionally, we investigated the diversity of pathogenicity among these isolates and conducted an assay to evaluate the response of grape cultivars to P. viticola infection. Lemon-shaped sporangia were identified in the collected isolates, which released zoospores into the suspension at room temperature. Within a few hours of inoculation, the zoospores developed germ tubes. We tested 11 P. viticola isolates for pathogenicity in 845 grape cultivars to screen for grape host resistance to downy mildew infection. Among the tested isolates, JN-9 showed the highest virulence. Grape cultivars displayed varying phenotypic reactions to P. viticola infection: approximately 7% were highly susceptible, 41% were susceptible, 20% were moderately susceptible, 8% were resistant, and 24% exhibited extreme resistance. Phylogenetic analysis based on four genomic regions (internal transcribed spacer 1 [ITS1], actin, beta-tubulin, and cytochrome c oxidase II) revealed a close evolutionary relationship among all the Korean isolates, forming a single monophyletic lineage. Notably, these isolates showed greater similarity to European isolates than to American isolates. This comprehensive study contributes to a deeper understanding of the identity and behavior of P. viticola, which is crucial for developing effective resistance strategies against this pathogen in grape cultivars cultivated in South Korea.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.24 no.2
• /
• pp.17-26
• /
• 1979

Comparative tolerance of the new rice varieties from Indicax Japonica cross to elastic and plastic chilling injuries was examined at the 3rd leaf-stage, the most sensitive stage to chilling during nursery, using a chilling chamber set 11\circ C, 13hrs. 20K lux day/5$^{\circ}C$ night. Seedlings were reared until 35 days after seeding in a 26\circ C, 13hrs. day / 18\circ C night chamber except the period of chilling treatment for 0, 3, 4, 6, 8 or 10 days. The new varieties were approximately twice susceptible to elastic injuries, and thrice susceptible to plastic injuries than the Japonica varieties in the term of chilling duration. Among the variables indicating apparant chilling injuries the reduction in dry matter responded most sensitively and differentiated well the varietal difference in chilling resistance even with shorter chilling period. Sequential aspects of the cause and effect relations involved in the development of the apparant chilling injuries are discussed and a schematic diagram is presented as Fig. 5 in the text.

• Journal of Mushroom
• /
• v.9 no.4
• /
• pp.170-179
• /
• 2011

In coculturing with strains of Trichoderma and oyster mushroom, we could detect the difference in the resistance of oyster mushroom against Trichoderma with the phenomena of barrage reaction, overgrowth and lysis. We selected the isolates ASI 2183, ASI2504 and ASI 2477 as varieties that showed the resistance. The isolates ASI 2240, ASI 2479 and ASI 2181 were the best in their resistance against Trichoderma in the method using culture filtrate. In common, the isolates ASI 2479 and ASI 2240 were selected in both methods. In post-inoculation method, the isolates ASI 2479, ASI 2333 and ASI 2181 were selected and ASI 2302 was susceptible. For the same isolate of Trichoderma, the resistance varied depending on the isolates of oyster mushroom used in the experiments. Because we could detect the interactions between Trichoderma and oyster mushroom, it is possible to detect the level of the resistance that differs in the varieties. However, there were the cases of detecting the level of the resistance in repetitions with the same isolate, which may be caused by the vitality of isolates of Trichoderma and oyster mushroom. It is efficient to test the resistance with the resistant isolate of Pleurotus salmoneostramine and the susceptible isolate of ASI 2302.

• Plant Disease and Agriculture
• /
• v.5 no.1
• /
• pp.8-13
• /
• 1999

Twenty two different disease on strawberry have been reported in Korea. Their occurrence patterns were depended on the varieties cultivated. Fusarium wilt occurred seriously on var. Hokowase, a variety used for the fields or semi-forcing culture. In recent years, however, anthracnose occurred remarkably as the acreage of forcing culture increases. Consequently, anthracnose reduced the stand rate and yield of the strawberry. Average occurrence rate of anthracnose was 36.9% on major strawberry cropping areas. Nyoho and Akihime, which are popular varieties for the forcing culture, are considered to be susceptible, but Holiwase and Suhong are resistant against this disease. Colletotrichum gloeosporioides and Glomerella cingulata have been reported as casual agents for this disease in Korea. C. gloeosporoides was recently reported, but C. fragariae, known to be a strong pathogen in foreign countries, has bot been found yet in Korea. These two fungal pathogens showed significant differences in some characteristics such as major infection parts of plant and responses to temperatures as well as benomyl resistance. In addition, C. gloeosporioides is more pathogenic than G. cingulata. Because vinly sheltering is effective for control of anthracnose to protect water disposal of the pathogen during the seedling stages, it is strongly recommend to use this method in conjunction with integrated control programs.

• Korean Journal of Agricultural Science
• /
• v.4 no.2
• /
• pp.191-198
• /
• 1977

This study was conducted to determine the inheritance to bacterial leaf blight in rice. Varieties used in the study were IR1544-349-2, IR1698-237-2, IR1529-680-3, IR28, IR29, RP663-337-7-8-4-1-1, RP291-20, 62-595 and Kele. The isolate of bacteial leaf blight used was 71-23, 76-1 of Xanthomonas oryzae. $F_1s$ were obtained from crosses between resistant and susceptible varieties. Field observation was made from the Parents, $F_1s$ and $F_2$ sagregating population. The result is summaryzed as fallow: 1) The resistance to the bacterial leaf blight (71-23) derived from cultivars IR1529-680-3, IR28, IR29, RP663-337-7-8-4-1-1, RP291-20 and 62-595 was controlled by a single dominant gene. 2) The resistance to the bacterial leaf blight (71-23) derived from cultivars IR1545-339-2, IR1544-340, IR1698-237-2 and Kele was controlled by a single recessive gene. 3) The resistance to the bacterial leaf blight (76-1) derived from cultivars IR1545-339-2, IR1544-340, IR 1698-237-2 was controlled by a single dominant gene. 4) Degree of resistance to the bacterial leaf blight and genetic type were different depending on isolates within the same resistant cultivar. 5) There was no relation between resistance to the bacterial leaf blight and heading days.

• Korean Journal Plant Pathology
• /
• v.13 no.2
• /
• pp.90-94
• /
• 1997

Interaction of races of rice blast fungus and cultivars has been evaluated. Dongjinbyeo was infected by four KJ races and two KI races, while other varieties were susceptible to four to six KJ or KI races. Among the single spores reisolated from the leaf blast lesion of Dongjinbyeo after mixed inoculation of 10 races, 63% was race KJ-301 which produced a small number and small size lesions, while 30% was race KI-313 which produced a large number of lesions. However, 93% of single spores reisolated from Palgongbyeo was a highly virulent race KJ-105. On the other hand, all the races were equally reisolated from the susceptible cultivar Jinmibyeo. Frequency of races isolated from the naturally infected leaf blast lesions in the field was similar to that of reisolated races from the cultivars inoculated with 10 mixed races in the greenhouse. However, 30% of single spores isolated from the naturally infected Dongjinbyeo was race KI-329 ut ace KI-313 was not detected. Genetic relationship of the isolates collected from leaf and neck blast fungus of Jinmibyeo and Nakdongbyeo showed specific bands on RFLP-P64, However, their genetic similarity was 80%.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.188-188
• /
• 2022

Our previous study identified a resistance locus to Phytophthora sojae (isolate 2457) in an interval of 3.8-4.7 Mbp on chromosome 3 via genetic mapping using a 'Daepung'×'Daewon' recombinant inbred population. Since differential gene expression between Daepung (susceptible) and Daewon (resistant) after inoculation of P. sojae is unknown, RNA sequencing was carried out to compare transcriptomic changes between the two genotypes following inoculation with P. sojae isolate 2457. The two varieties were inoculated using hypocotyl inoculation at the VC stage and stem tissue of 1 cm above and below of the inoculated site were sampled at 0, 6, 12 hours after inoculation (hai), respectively. Differentially expressed genes (DEGs) under same cultivar in different time point and Daepung vs. Daewon in same time point were investigated. In comparison of Daepung vs. Daewon at 12 hai, a total of 3,513 DEGs were identified, including two nucleotide-binding site-leucine rich repeat (NBS-LRR) genes (Glyma.03g034800 and Glyma.03g034900) that are located in the previously reported resistance locus on chromosome 3. In addition, 14,966 DEGs were detected between 0 vs. 6 hai, containing one of candidate genes (Glyma.03g035300). This gene was upregulated by up to 4-fold in Daewon and Daepung. Additional results will be further discussed in the presentation. This study will provide valuable information for soybean crop improvement.

• Research in Plant Disease
• /
• v.12 no.2
• /
• pp.75-80
• /
• 2006

Crown gall on rose was observed in greenhouse during year 2003-2005. The disease incidence was up to 28.3% and the disease was the severer in hydrophonics culture than that in soil. The typical gall symptom occurred mainly on the root and crown resulting in poor foliage, stunting, and fewer blossoms. Sixty-three rose cultivars were inoculated with Agrobacterium. tumefaciens isolated from rose crown gall, to evaluate rose cultivar-specific resistance. The size of galls from inoculated rose stems was measured in a greenhouse test. Tumors formed in almost varieties of rose inoculated. Based on the frequency of tumor occurrence and weight of galls formed on the stem of rose, it was shown that 'Little Marble', 'Golden Gate' and 'Rosa Rox-ette' were extremely susceptible to crown gall. Some varieties such as 'Little Silver' appeared to be resistant to the crown gall.

• Research in Plant Disease
• /
• v.19 no.3
• /
• pp.188-195
• /
• 2013

This study was carried out for the downy mildew resistant test between 2010 and 2012. A set of 22 accessions belonging to 2 wild species and 20 varieties of the genus Cucumis, originating mainly from the Asian Vegetable Research and Development Center (AVRDC) Gene Centre, was evaluated for resistance to Pseudoperonospora cubensis, causal agent of cucumber downy mildew. The youngest fully expanded true leaves were found suitable for in vitro screening. Both leaf discs and full leaves could be kept fresh longer when applying 0.2 ${\mu}g/ml$ of gibberellin acid (GA). The incubation temperature of $20^{\circ}C$ was found to be the most suitable temperature for symptom development comparing with 15 and $25^{\circ}C$. Symptom development was faster when contact diseased leaf discs (2 weeks after inoculation) on to fresh leaf samples comparing with using conidia suspension ($10^5$ spores/ml). The numbers of spots in 'C-19' were lower than other varieties. 'C-19' variety was also showed the highest level of downy mildew resistant at $20^{\circ}C$ chamber in 6 days after inoculating with pathogen and displayed 0.90 (under 10%) of the infected rate. However, other varieties displayed susceptible in the pathogen sprayed plots. 'C-19' was the most resistant variety and no lesion was observed. Based on all data, 'C-19' can be a useful variety for the prevention of downy mildew.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.51 no.5
• /
• pp.477-482
• /
• 2006

Viral diseases, especially Barley yellow mosaic virus (BaYMV) and Barley mud mosaic virus (BaMMV), have been most serious in barley fields. In this study, we investigated the effect of different level of resistance to viral diseases on the plant growth and yield in barley. Various viral disease symptoms on leaves of overwintered plants were similar between medial-resistant and susceptible varieties of Saessalbori and Baegdong. In diagnosis of virus infection, BaYMV and BaMMV were detected in Saessalbori and Baegdong, but not in the resistant variety, Naehanssalbori. Plant height was restrained about $11{\sim}12cm$ prior to heading in Saessalbori and Baegdong comparing to Naehanssalbori. Even if both varieties were medial resistant to virus diseases, Saessalbori was different from Baegdong in heading date and culm length due to its recovery from viral damages prior to heading. Both medial-resistant and susceptible varieties were quite different from the resistant variety in yield components such as heading date, number of spikes and culm length when evaluated in the virus-infected or non-infected field. Baegdong delayed 7 days in heading date and reduced by more than 50% in culm length and spike numbers as compared to Naehanssalbori. On the other hand, Saessalbori showed similar heading date, but was shorter by 20% in culm length than Naehanssalbori. Three varieties tested in the non-infected field over two years were not significantly different for yield potential with ranges of $340{\sim}405kg/10a$. However, significant yield reduction (P<0.01) was observed in Saessalbori and Baegdong with ranges of $108{\sim}288kg/10a$ as compared to Naehanssalbori (391 kg/10a) when tested in the virus-infected field. Yield potentials of Saessalbori and Baegdong reduced by 35 and 63%, respectively in the virus-infected field as compared to those in the non-infected field. Our results showed that damages from virus diseases were significant on the early plant growth to yield and its components in barley.