• The Plant Pathology Journal
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• 제34권6호
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• pp.480-489
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• 2018

Bitter rot caused by Colletotrichum species is a common fruit rotting disease of apple and one of the economically important disease in worldwide. In 2015 and 2016, distinct symptoms of bitter rot disease were observed in apple orchards in five regions of South Korea. In the present study, infected apples from these regions were utilized to obtain eighteen isolates of Colletotrichum spp. These isolates were identified and characterized according to their morphological characteristics and nucleotide sequence data of internal transcribed spacer regions and glyceraldehyde-3-phosphate-dehydrogenase. Molecular analyses suggested that the isolates of Colletotrichum causing the bitter rot disease in South Korea belong to 4 species: C. siamense; C. fructicola; C. fioriniae and C. nymphaeae. C. siamense and C. fructicola belonged to Musae Clade of C. gloeosporioides complex species while C. fioriniae and C. nymphaeae belonged to the Clade 3 and Clade 2 of C. acutatum complex species, respectively. Additionally, we also found that the isolates of C. gloeosporioides species-complex were more aggressive than those in the C. acutatum species complex via pathogenicity tests. Taken together, our results suggest that accurate identification of Colletotrichum spp. within each species complex is required for management of bitter rot disease on apple fruit in South Korea.

• The Plant Pathology Journal
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• 제40권1호
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• pp.16-29
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• 2024

The Colletotrichum gloeosporioides species complex includes many phytopathogenic species, causing anthracnose disease on a wide range of host plants and appearing to be globally distributed. Seventy-one Colletotrichum isolates in the complex from different plants and geographic regions in Korea were preserved in the Korean Agricultural Culture Collection (KACC). Most of them had been identified based on hosts and morphological features, this could lead to inaccurate species names. Therefore, the KACC isolates were re-identified using DNA sequence analyses of six loci, comprising internal transcribed spacer, gapdh, chs-1, his3, act, and tub2 in this study. Based on the combined phylogenetic analysis, KACC strains were assigned to 12 known species and three new species candidates. The detected species are C. siamense (n = 20), C. fructicola (n = 19), C. gloeosporioides (n = 9), C. aenigma (n = 5), C. camelliae (n = 3), C. temperatum (n = 3), C. musae (n = 2), C. theobromicola (n = 2), C. viniferum (n = 2), C. alatae (n = 1), C. jiangxiense (n = 1), and C. yulongense (n = 1). Of these, C. jiangxiense, C. temperatum, C. theobromicola and C. yulongense are unrecorded species in Korea. Host plant comparisons showed that 27 fungus-host associations are newly reported in the country. However, plant-fungus interactions need to be investigated by pathogenicity tests.

• The Plant Pathology Journal
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• 제39권4호
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• pp.384-396
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• 2023

Colletotrichum acutatum species complex is one of the most important groups in the genus Colletotrichum with a high species diversity and a wide range of host plants. C. acutatum and related species have been collected from different plants and locations in Korea and deposited into the Korean Agricultural Culture Collection (KACC), National Institute of Agricultural Sciences since the 1990s. These fungal isolates were previously identified based mainly on morphological characteristics, and a limitation of molecular data was provided. To confirm the identification of species, 64 C. acutatum species complex isolates in KACC were used in this study for DNA sequence analyses of six loci: nuclear ribosomal internal transcribed spacers (ITS), betatubulin 2 (TUB2), histone-3 (HIS3), glyceraldehyde3-phosphate dehydrogenase (GAPDH), chitin synthase 1 (CHS-1), and actin (ACT). The molecular analysis revealed that they were identified in six different species of C. fioriniae (24 isolates), C. nymphaeae (21 isolates), C. scovillei (12 isolates), C. chrysanthemi (three isolates), C. lupini (two isolates), and C. godetiae (one isolate), and a novel species candidate. We compared the hosts of KACC isolates with "The List of Plant Diseases in Korea", previous reports in Korea and global reports and found that 23 combinations between hosts and pathogens could be newly reported in Korea after pathogenicity tests, and 12 of these have not been recorded in the world.

• Mycobiology
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• 제46권2호
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• pp.92-100
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• 2018

The filamentous Ascomycota Colletotrichum gloeosporioides sensu lato is a fungus that has been reported worldwide as a causal agent of anthracnose disease in avocado and other crops. In Mexico, this species affects fruits from an early stage of development in the orchard until the post-harvest stage. Although fungicides are continuously applied to control Colletotrichum species, pericarp cankers and soft rot mesocarp in fruits are still frequently observed. Considering the lack of a precise description of the causative agent, the aim of the current study was to determine the pathogens involved in this symptomatology. Twenty-four isolates were consistently obtained from the pericarp of avocado fruits cv. "Hass" collected in the central avocado-producing area of Mexico. Morphological features such as colony growth, conidia size, and mycelial appressorium were assessed. Bayesian multilocus phylogenetic analyses were performed using amplified sequences of the internal transcribed spacer region of the nuclear ribosomal DNA; actin, chitin synthase, glyceraldehyde-3-phosphate dehydrogenase partial genes; and APn2-Mat1-2 intergenic spacer and mating type Mat1-2 partial gene from the nine selected isolates. In addition, fruits were inoculated with a conidial suspension and reproducible symptoms confirmed the presence of Colletotrichum fructicola in this area. This pathogenic species can now be added to those previously reported in the country, such as C. acutatum, C. boninense, C. godetiae, C. gloeosporioides, and C. karstii. Disease management programs to reduce the incidence of anthracnose should include C. fructicola to determine its response to fungicides that are routinely applied, considering that the appearance of new species is affecting the commercial quality of the fruits and shifting the original population structure.

• Journal of Forest and Environmental Science
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• 제37권2호
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• pp.154-162
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• 2021

Blueberry, which produces phenolic compounds, is one of the most popular fruits in Korea. During a survey on blueberry diseases, 16 Colletotrichum isolates were obtained from blueberry leaves in Chuncheon and Gosung, Kangwon province, Korea. Using morphological and molecular analyses, the isolates were identified as Colletotrichum aenigma, C. fioriniae, C. fructicola, C. gloeosporioides, and C. nymphaeae. C. gloeosporioides was the most frequently isolated (11 isolates), and only one or two isolates of the other species were found. After inoculation with all isolates, those leaves and fruits with wounds easily developed anthracnose; whereas, fruits without wounds became infected but leaves without wounds were infected by only two of C. gloeosporioides. Typically, around seven fungicidal agents are used to control anthracnose on blueberries in Korea. Fluzinam and prochloraz manganese complex strongly (over than 80%) inhibited the growth of all Colletotrichum species, while dithianon and mancozeb only weakly (about 80% or less) inhibited their growth.

• The Plant Pathology Journal
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• 제33권2호
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• pp.118-124
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• 2017

Bell pepper is an economically important crop worldwide; however, production is restricted by a number of fungal diseases that cause significant yield loss. Chemical control is the most common approach adopted by growers to manage a number of these diseases. Monitoring for the development to resistance to fungicides in pathogenic fungal populations is central to devising integrated pest management strategies. Two fungal species, Fusarium incarnatum-equiseti species complex (FIESC) and Colletotrichum truncatum are important pathogens of bell pepper in Trinidad. This study was carried out to determine the sensitivity of 71 isolates belonging to these two fungal species to fungicides with different modes of action based on in vitro bioassays. There was no significant difference in log effective concentration required to achieve 50% colony growth inhibition ($LogEC_{50}$) values when field location and fungicide were considered for each species separately based on ANOVA analyses. However, the $LogEC_{50}$ value for the Aranguez-Antracol locationfungicide combination was almost twice the value for the Maloney/Macoya-Antracol location-fungicide combination regardless of fungal species. $LogEC_{50}$ values for Benomyl fungicide was also higher for C. truncatum isolates than for FIESC isolates and for any other fungicide. Cropping practices in these locations may explain the fungicide sensitivity data obtained.

• 식물병연구
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• 제29권4호
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• pp.345-362
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• 2023

탄저병원균(Colletotrichum) 속의 많은 식물병원균은 한국을 비롯하여 전 세계 과수 생산에 큰 위협이 된다. 사과, 감, 자두, 복숭아, 대추, 포도 및 호두와 같은 과실에서 탄저병과 관련된 탄저병원균의 종이 동정되었다. 형태적, 다중 유전자의 계통발생적 및 병원성 시험이 다양한 접근으로 실시되었다. 동정된 탄저병원균의 종에 대한 감수성은 살균제에 대하여 평가하였다. 2종의 종복합체인 gloeosporioides와 acutatum에 속한 9종의 탄저병원균이 국내 과실에 탄저병의 주요 원인균으로 동정되었다. Colletotrichum gloeosporioides 종 복합체 안에는 6종인 C. aenigma, C. fructicola, C. gloeosporioides, C. horii, C. siamense 및 C. viniferum이 있는 반면, Colletotrichum acutatum 종 복합체 안에 종은 C. fioriniae, C. nymphaeae 및 C. orientalis이 동정되었다. 사과 탄저병원균은 C. fructicola, C. siamense, C. fioriniae 및 C. nymphaeae, 자두 탄저병원균은 C. siamense, C. fioriniae 및 C. nymphaeae, 복숭아 탄저병원균은 C. siamense, C. fructicola 및 C. fioriniae, 감 탄저병원균은 C. siamense, C. horii 및 C. nymphaeae, 오미자 탄저병원균은 C. fioriniae, 호두탄저병원균은 C. orientalis, 대추탄저병원균은 C. nymphaeae, 포도 탄저병원균인 C. aenigma, C. fructicola 및 C. siamense를 국내 과수류의 과실에 병을 일으키는 병원균의 종류로 처음 국제학술지에 보고되었다. 이들 병원균의 종에 대한 살균제의 감수성 시험에서 여러 살균제에 대한 탄저병원균의 종 간에 EC₅₀값이 매우 다양하여 감수성의 차이가 크게 나타났다.

• 한국균학회지
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• 제48권3호
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• pp.297-312
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• 2020

2014년부터 2016년까지 국내 콩 재배 포장에서 시들음 증상을 보이는 시료에서 진균을 분리한 결과, Fusarium spp., Colletotrichum spp., Rhizoctonia spp., Macrophomina sp., Phytophthora spp., Calonectria ilicicola가 분리되었고, Fusarium균이 79.1%로 가장 많이 분리되었다. 53개의 Fusarium균을 균학적 특성에 의해 동정한 결과, F. solani, F. oxysporum, F. graminearum, F. fujikuroi 등 4개의 종 복합체(species complex)로 동정되었다. 염기서열분석을 통한 종 동정을 위해 translation elongation factor 1 alpha (TEF) 유전자 부위를 계통분석한 결과, F. solani, F. oxysporum, F. commune, F. asiaticum, F. fujikuroi 등 5종으로 확인되었다. 44개 Fusarium균주의 병원성을 확인하기 위하여 콩 3개 품종을 대상으로 유묘 침지 접종한 결과, F. asiaticum은 병원성이 없거나 미미한 것으로 나타났다. 병원성이 있는 10개 균주를 선발하여 기주범위를 조사한 결과, F. solani, F. oxysporum, F. commune은 콩에만 병원성이 있었고, F. fujikuroi는 콩, 강낭콩, 황동부콩, 흑동부콩 및 팥에 병원성을 보였다. 또한 13개 콩 품종을 대상으로 저항성 검정을 수행한 결과, F. commune과 F. fujikuroi는 모든 품종에 병을 일으켰다. 장기콩, 풍산나물콩, 소청자콩은 Fusarium에 의한 시들음병에 비교적 저항성이 것으로 나타났고, 황금올콩, 참올콩은 감수성 품종으로 확인되었다.

• The Plant Pathology Journal
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• 제37권3호
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• pp.307-314
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• 2021

Pepper (Capsicum annuum L.) is an important agricultural crop worldwide. Recently, Colletotrichum scovillei, a member of the C. acutatum species complex, was reported to be the dominant pathogen causing pepper anthracnose disease in South Korea. In the present study, we isolated bacterial strains from rhizosphere soil in a pepper field in Gangwon Province, Korea, and assessed their antifungal ability against C. scovillei strain KC05. Among these strains, a strain named BS1 significantly inhibited mycelial growth, appressorium formation, and disease development of C. scovillei. By combined sequence analysis using 16S rRNA and partial gyrA sequences, strain BS1 was identified as Bacillus velezensis, a member of the B. subtilis species complex. BS1 produced hydrolytic enzymes (cellulase and protease) and iron-chelating siderophores. It also promoted chili pepper (cv. Nockwang) seedling growth compared with untreated plants. The study concluded that B. velezensis BS1 has good potential as a biocontrol agent of anthracnose disease in chili pepper caused by C. scovillei.

• 한국균학회지
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• 제50권3호
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• pp.235-241
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• 2022

Anthracnose crown rot (ACR) has been observed in greenhouses during the nursery and harvest seasons in Gangwon Province, Korea. Infected plants showed black leaf spot, dark sunken pink conidial masses on petioles, wilting, and eventually death. Five isolates were obtained from the lesions of strawberry plants and were identified as a Colletotrichum gloeosporioides species complex based on their cultural and morphological characteristics. Multilocus sequence analysis of actin, calmodulin, chitin synthase, glyceraldehyde-3-phophate dehydrogenase genes, and internal transcribed spacer rDNA regions showed that the isolates formed a monophyletic group with the type strain of C. siamense. Pathogenicity tests were performed on the isolate, and Koch's postulates were performed to verify the relationship between Colletotrichum sp. and the strawberry plant variety Seolhyang. The isolate was pathogenic to strawberry plants, which exhibited typical ACR symptoms. Based on morphological characteristics, pathogenicity, and DNA sequence analyses, the fungus isolated in Korea was identified as C. siamense. This is first time C. siamense has been confirmed in ever-bearing strawberry varieties in Korea.