• The Plant Pathology Journal
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• 제40권1호
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• pp.59-72
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• 2024

A comprehensive survey of mungbean-growing areas was conducted to observe leaf spot disease caused by Alternaria alternata. Alternaria leaf spot symptoms were observed on the leaves. Diversity of 50 genotypes of mungbean was assessed against A. alternata and data on pathological traits was subjected to cluster analysis. The results showed that genotypes of mungbean were grouped into four clusters based on resistance parameters under the influence of disease. The principal component biplot demonstrated that all the disease-related parameters (% disease incidence, % disease intensity, lesion area, and % of infection) were strongly correlated with each other. Alt a 1 gene that is precisely found in Alternaria species and is responsible for virulence and pathogenicity. Alt a 1 gene was amplified using gene specific primers. The isolated pathogen produced similar symptoms when inoculated on mungbean and tobacco. The sequence analysis of the internal transcribed spacer (ITS) region, a 600 bp fragment amplified using specific primers, ITS1 and ITS2 showed 100% identity with A. alternata. Potato virus X (PVX) -based silencing vector expressing Alt a 1 gene was constructed to control this pathogen through RNA interference in tobacco. Out of 50 inoculated plants, 9 showed delayed onset of disease. Furthermore, to confirm our findings at molecular level semi-quantitative reverse transcriptase polymerase chain reaction was used. Both phenotypic and molecular investigation indicated that RNAi induced through the VIGS vector was efficacious in resisting the pathogen in the model host, Tobacco (Nicotiana tabacum). To the best of our knowledge, this study has been reported for the first time.

• 한국균학회지
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• 제51권3호
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• pp.179-190
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• 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.

• 한국가금학회지
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• 제46권3호
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• pp.173-183
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• 2019

조류인플루엔자 바이러스 H7 subtype에 속하는 바이러스 중 일부는 가금류에 감염할 경우 고병원성이 발휘된다. 또 H7 아형 AIV중 일부는 사람에 감염하여 사망 등을 유발할 수도 있다. 본 연구는 야생조류로부터 분리된 H7 아형 조류인플루엔자 바이러스 6주(H7N7 아형 4주, H7N1 아형 2주)를 대상으로 8개 유전자 분절 전체의 염기서열을 분석하여 병원성, 사람 감염 가능성 등 그 특성을 조사하였다. 계통유전학적 분석결과, 국내에서 분리된 H7 아형 분리주들은 8개 유전자(HA, NA, PB2, PB1, PA, NP, M, NS) 모두 Eurasian lineage로 분류되었으나, Eurasian lineage 내에서도 각기 다른 sublineage로 분류되어 유전적 다양성이 있는 것으로 분석되었다. 한국 분리주 6주는 HA 단백질 분절부위 아미노산은 두 종류(PEIPKGR 및 PELPKGR)의 motif를 가지고 있었으나, 모두 저병원성 바이러스 특성을 가지고 있었다. 숙주세포 결합 특이성과 관련 있는 HA 단백질 receptor-binding site를 분석한 결과, 한국 분리주 모두는 사람 세포 수용체 결합특이성보다는 조류 세포 수용체 결합 특이성을 가지는 것으로 나타났다. 사람 감염 가능성을 높게 하는 부위에서의 아미노산 치환(PB2 단백질의 E627K 및 PB1단백질의 I368V)도 나타나지 않았고, 또한 NA stalk region에서의 결손도 관찰되지 않았다. 이상의 결과를 미루어 볼 때 한국 야생조류에서 분리된 H7 아형 6주 모두는 저병원성 바이러스로 최근 중국에서 사람 감염이 나타나고 있는 H7N9 바이러스와는 유전적으로 다른 계열의 바이러스인 것으로 판단된다.