1.Exploration of Mycobiota in Cypripedium japonicum, an Endangered Species
Gyeongjun CHO ; Geun-Hye GANG ; Hee-Young JUNG ; Youn-Sig KWAK
Mycobiology 2022;50(2):142-149
Orchids live with mycorrhizal fungi in mutualism. This symbiotic relationship plays an essential role in the overall life cycle of orchids from germination, growth, settlement, and reproduction. Among the 1000 species of the orchid, the Korean lady’s slipper, Cypripedium japonicum, is known as an endangered species. Currently, only five natural habitats of the Korean lady’s slipper remain in South Korea, and the population of Korean lady’s slipper in their natural habitat is not increasing. To prevent extinction, this study was designed to understand the fungal community interacting in the rhizosphere of the Korean lady’s slipper living in the native and artificial habitats. In-depth analyses were performed to discover the vital mycorrhizal fungi contributing to habitat expansion and cultivation of the endangered orchid species. Our results suggested that Lycoperdon nigrescens contributed most to the increase in natural habitats and Russula violeipes as a characteristic of successful cultivation. And the fungi that helped L. nigrescens and R. violeipes to fit into the rhizosphere community in Korean lady’s slipper native place were Paraboeremia selaginellae and Metarhizium anisopliae, respectively. The findings will contribute to restoring and maintaining the endangered orchid population in natural habitats.
2.Genetic Variation of Strawberry Fusarium Wilt Pathogen Population in Korea
Mycobiology 2022;50(1):79-85
Strawberries are a popular economic crop, and one of the major plantations and exporting countries is Korea in the world. The Fusarium oxysporum species complex (FOSC) is a soil-borne pathogen with genetic diversity, resulting in wilt disease in various crops. In Korea, strawberries wilt disease was first reported in the 1980s due to the infection of FOSC, causing significant economic damage every year. The causal agent, F. oxysporum f. sp. fragariae, is a soil-borne pathogen with a characteristic of FOSC that is difficult to control chemically and mutates easily. This study obtained genetic polymorphism information that was based on AFLP, of F. oxysporum f. sp. fragariae 91 strains, which were isolated from strawberry cultivation sites in Gyeongsangnam-do and Chungcheongnam-do, and compared strains information, which was the isolated location, host variety, response to chemical fungicide, and antagonistic bacteria, and mycelium phenotype. As a result, AFLP phylogeny found that two groups were mainly present, and group B was present at a high frequency in Gyeongsangnam-do. Group B proved less sensitive to tebuconazole than group A through Student’s t-test. In addition, the fractions pattern of AFLP was calculated by comparing the strain information using PCA and PERMANOVA, and the main criteria were separated localization and strawberry varieties (PERMANOVA; p < 0.05). And tebuconazole was different with weak confidence (PERMANOVA; p < 0.10). This study suggests that the F. oxysporum f. sp. fragariae should be continuously monitored and managed, including group B, which is less chemically effective.
3.First Report of Stemonitis splendens Rostaf Causing Bark Decay of Oak Logs Used for Shiitake Cultivation in Korea.
Jung Han LEE ; Da Ran KIM ; Youn Sig KWAK
Mycobiology 2014;42(3):279-281
Severe bark decay disease was observed on oak logs at a shiitake cultivation farm in Geochang-gun, Gyeongnam province. The symptoms observed were fruiting bodies that had developed on the top and side surface of oak logs. As a result, the bark came off easily exposing the sapwood. Slime mold specimens collected from oak logs showed developing fruiting bodies comprising of stalks, hypothallus, capillitium, and columella, and the causal agent of bark decay disease was identified as Stemonitis splendens on the basis of morphological characteristics. To our knowledge, this is the first report of Stemonitis splendens causing bark decay of oak logs used for shiitake mushroom cultivation in Korea.
Fruit
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Fungi
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Korea
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Shiitake Mushrooms
4.First Report of Black Spot Disease Caused by Alternaria alternata on Sweet Persimmon Fruits.
Jung Han LEE ; Jinwoo KIM ; Youn Sig KWAK
Mycobiology 2013;41(3):167-169
Black spot of sweet persimmon, caused by Alternaria alternata, occurred in an orchard in Gyeongnam province, Korea in 2012. The symptom was appearance of 0.5 to 4 cm black spots on the surface of fruit. The pathogen was isolated from flesh of disease lesions. The causal agent was identified as A. alternata by morphological characteristics and sequencers of the internal transcribed spacer (ITS) 1 and ITS4 regions of rRNA. Artificial inoculation of the pathogen resulted in development of disease symptoms and the re-isolated pathogen showed characteristics of A. alternata.
Alternaria*
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Diospyros*
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Fruit*
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Korea
5.Morphological and Molecular Characteristics of the Oak Tree Canker Pathogen, Annulohypoxylon truncatum.
Jaeyul CHA ; Bitna HEO ; Soo Jeong AHN ; Guenhye GANG ; Chung Gyoo PARK ; Youn Sig KWAK
Mycobiology 2012;40(1):79-81
Cankers are localized dead areas in the bark of stems, branches or twigs of many types of trees and shrubs, and are usually caused by fungi. We observed severe canker symptoms in oak trees located in Gyeongnam province in 2011. A total 31 trees were discovered with cankers of varied size, with an average of 48.5 x 15.2 cm. Black, half-rounded globular mound shaped stromata were associated with the cankers, and the asci of the fungi associated with the cankers were cylindrical shaped with their spore-bearing parts being up to 84 microm in length. The average fungal ascospores size was 7.59 x 4.23 microm. The internal transcribed spacer sequence for the canker causing fungus showed 99% similarity to the sequence of Annulohypoxylon truncatum. In this study, the isolated fungus was precisely described and then compared with fungi of similar taxa.
Fungi
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Quercus
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Trees
6.Distribution of Rhizosphere and Endosphere Fungi on the First-Class Endangered Plant Cypripedium japonicum.
Geun Hye GANG ; Gyeongjun CHO ; Youn Sig KWAK ; Eun Hee PARK
Mycobiology 2017;45(2):97-100
Endangered native plant habitats and populations are rapidly disappearing because of climate and environmental changes. As a representative, the abundance of the first-class endangered wild plant, Cypripedium japonicum, has been rapidly decreasing in Korea. The purpose of this study was to evaluate the distribution of rhizosphere and endophytic fungi on C. japonicum in its native habitat. A total of 440 rhizosphere and 79 endosphere fungi isolates were isolated and identified on the basis of their molecular characteristics. Sixty-five genera and 119 fungi species were identified in this study. The genus Trichoderma showed the highest abundance among both rhizosphere and endosphere fungi. Mortierella, Hypocrea, and Penicillium spp. were also relatively dominant species on C. japonicum. The community structures of rhizosphere and endosphere fungi were similar, but endosphere fungi showed greater diversity.
Climate
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Ecosystem
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Fungi*
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Hypocrea
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Korea
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Mortierella
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Penicillium
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Plants*
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Rhizosphere*
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Trichoderma
7.Spot Anthracnose Disease Caused by Colletotrichum gloeosporioides on Tulip Tree in Korea.
Okryun CHOI ; Okhee CHOI ; Youn Sig KWAK ; Jinwoo KIM ; Jin Hyeuk KWON
Mycobiology 2012;40(1):82-84
The tulip tree (Liriodendron chinense) has been widely cultivated in Korea as a street or garden tree for its large flowers, which have a superficial resemblance to tulips. Occurrence of anthracnose disease on the leaves of tulip trees growing on the campus of Gyeongsang National University, Jinju, Korea, has been observed. Based on mycological characteristics, pathogenicity, and internal transcribed spacer sequence, the causal fungus was identified as Colletotrichum gloeosporioides. This is the first report on anthracnose disease caused by C. gloeosporioides on tulip trees in Korea.
Colletotrichum
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Flowers
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Fungi
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Korea
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Liriodendron
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Trees
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Tulipa
8.Occurrence of Sooty Blotch and Flyspeck Disease on Sweet Persimmon in Korea.
Jin Hyeuk KWON ; Jinwoo KIM ; Okhee CHOI ; Guenhye GANG ; Youn Sig KWAK
Mycobiology 2012;40(3):210-213
Sooty blotch and flyspeck (SBFS), a disease caused by a complex of fungi, results in substantial economic losses for commercial growers of sweet persimmon (Diospyros kaki L.) in Korea. However, many species causing SBFS in Korea have not been identified and sources of inoculum are uncertain. Based on mycological characteristics, pathogenicity, and molecular data, the causal fungi were identified as Dissoconium sp. and Zygophiala wisconsinensis. This is the first report of SBFS of sweet persimmon in Korea.
Diospyros
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Fungi
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Korea
9.Investigation of Fungal Strains Composition in Fruit Pollens for Artificial Pollination
Heeil DO ; Su-Hyeon KIM ; Gyeongjun CHO ; Da-Ran KIM ; Youn-Sig KWAK
Mycobiology 2021;49(3):249-257
Plants pollination are conducted through various pollinators such as wind, animals, and insects. Recently, the necessity for artificial pollination is drawing attention as the proportion of natural pollinators involved is decreasing over the years. Likewise, the trade in pollen for artificial pollination is also increasing worldwide. Through these imported pollens, many unknown microorganisms can flow from foreign countries. Among them, spores of various fungi present in the particles of pollen can be dispersed throughout the orchard. Therefore, in this study, the composition of fungal communities in imported pollen was revealed, and potential ecological characteristics of the fungi were investigated in four types of imported pollen. Top 10 operational taxonomic unit (OTU) of fungi were ranked among the following groups: Alternaria sp., Cladosporium sp., and Didymella glomerata which belong to many pathogenic species. Through FUNGuild analysis, the proportion of OTUs, which is assumed to be potentially plant pathogens, was higher than 50%, except for apple pollen in 2018. Based on this study of fungal structure, this information can suggest the direction of the pollen quarantine process and contribute to fungal biology in pollen
10.Investigation of Fungal Strains Composition in Fruit Pollens for Artificial Pollination
Heeil DO ; Su-Hyeon KIM ; Gyeongjun CHO ; Da-Ran KIM ; Youn-Sig KWAK
Mycobiology 2021;49(3):249-257
Plants pollination are conducted through various pollinators such as wind, animals, and insects. Recently, the necessity for artificial pollination is drawing attention as the proportion of natural pollinators involved is decreasing over the years. Likewise, the trade in pollen for artificial pollination is also increasing worldwide. Through these imported pollens, many unknown microorganisms can flow from foreign countries. Among them, spores of various fungi present in the particles of pollen can be dispersed throughout the orchard. Therefore, in this study, the composition of fungal communities in imported pollen was revealed, and potential ecological characteristics of the fungi were investigated in four types of imported pollen. Top 10 operational taxonomic unit (OTU) of fungi were ranked among the following groups: Alternaria sp., Cladosporium sp., and Didymella glomerata which belong to many pathogenic species. Through FUNGuild analysis, the proportion of OTUs, which is assumed to be potentially plant pathogens, was higher than 50%, except for apple pollen in 2018. Based on this study of fungal structure, this information can suggest the direction of the pollen quarantine process and contribute to fungal biology in pollen