• Korean Journal of Microbiology
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• v.29 no.1
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• pp.8-15
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• 1991

Interspecific hybrids between the ASpergillus spp., A. awamori, A. usamii and A. oryzae, were obtained by nuclear transfer technique. Nuclei isolated from an auxotrophic mutant strain were transferred into the protoplasts of a recipient strain of different species. The frequency of interspecific hybrid formation by nuclear transfer was $2*10^{-5}$ $-7*10^{-4}$ In contrast, no interspecific hybrid was isolated by protoplast fusion. Among the hybrids tested, 10 strains showed increased activity of some or all components of cellulases, xylanases and amylase up to more than two times. Isozyme pattern of the hybrids were analyzed by polyacrylamide gel electrophoresis and isoelectric focusing followed by activity staining, which showed that some of the hybrids have isozyme patterns unidentical to either of the two parents. By measuring the DNA contents and the sizes ofthe conidia, the karyotypes of the hybrids were estimated to be aneuploid near to haploid, diploid or triploid. It was concluded that the unclear transfer technique is much more efficient in the formation of interspecific hybrids than protoplast fusion and is very useful for the improvement of Aspergillus strains.

• The Korean Journal of Mycology
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• v.41 no.4
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• pp.292-294
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• 2013

In February 2010, the grayish fungus was found on Neofinetia falcata at Namsa-myeon, Yongin city, Gyeonggi-do, Korea. The symptoms start mainly on the leaves and stems, and the infected stems were rotten. Many conidia appeared on the lesions under humid condition. Colonies were grayish brown color and sclerotial formation was observed on potato dextrose agar (PDA). Conidia were mostly ellipsoidal to ovoid in shape, hyaline, one-celled, and $5.3-16.5{\times}3.8-11.0{\mu}m$ in size. Based on morphological characteristics and pathogenicity, the causal fungus was identified as Botrytis cinerea Pers. This is the first report of gray mold on N. falcata caused by B. cinerea in Korea.

• Research in Plant Disease
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• v.9 no.3
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• pp.145-148
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• 2003

In April of 2002, the gray mold disease occurred severely on kalanchoe (Kalanch oe blossfeldiana) grown in a nursery in Daesan-myon, Changwon City, Korea. The lesions were started with water-soaked spot and the leaves discolored from the tip and became gray or dark and gradully expanded to whole leaf. The conidia and mycelia of pathogen appearedd on flower, flower stalk and stem. Conidia were gray, 1-celled, mostly ellipsoid or ovoid in shape and were 8~17 ${\times}$5~12${\mu}m$ in size. Conidiophores were 13~34${\mu}m$ in size. The sclerotia were formed abundantly on potato-dextrose agar. The optimum temperature for sclerotial formation was $20^{\circ}C$. Pathogenicity of the causal organism was proved on Kalanchoe blossfeldiana according to Koch,s postulate. The causal organism was identified as Botrytis cinerea based on mycological characteristics. This is the first report on gray mold of Kalanchoe(Kalanchoe blossfeldiana) caused by Botrytis cinerea in Korea.

• Research in Plant Disease
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• v.10 no.4
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• pp.337-340
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• 2004

In April of 2003, the gray mold disease caused by Botrytis cinerea was occured in zinnia seedlings grown in greenhouse at Gyeongsangnam-do Agricultural Research and Extension Services, and farmer's nursery. The symptoms of infected plants were started with water-soaking lesions in flower bud, leaves and stems. The lesions gradually expanded and infected plants became withered and discolored to gray or dark from the tip. The conidia and mycelia of the pathogen were appeared on flowers, leaves and stem. The conidia were gray, 1-celled, mostly ellipsoid or ovoid in shape and were 5${\sim}$16 ${\times}$ 4${\sim}$8 ${\mu}m$ in size. Conidiophores were 12${\sim}$28 ${\mu}m$ in size. The pathogenic fungi formed sclerotia abundantly on potato dextrose agar. The optimum temperature for sclerotial formation was $20^{\circ}C$. Pathogenicity of the causal organism was proved according to Koch's postulate. The causal organism was identified as Botrytis cinerea Persoon: Fries based on mycological characteristics. This is the first report on gray mold of Zinnia elegans caused by Botrytis cinerea in Korea.

• The Korean Journal of Mycology
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• v.32 no.1
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• pp.50-53
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• 2004

In March of 2003, the gray mold occurred severely on pea (Pisum sativum) grown in the green houses and open fields in Changseon-myon, Namhae-gun, Gyeongnam Province, Korea. The symptoms started with water-soaking lesions in the leaves, stems and pods. The typical symptoms of the leaves, stems and pods became withered, discolored and blighted, and then eventually died. The mycelia, conidia and conidiophore of the pathogen appeared on leaves, stems and pods. The conidia were gray, 1-celled, mostly ellipsoid or ovoid in the shape and were $8{\sim}17{\times}5{\sim}13\;{\mu}m$ in size. Conidiophores were $14{\sim}30\;{\mu}m$ in size. The sclerotia were formed abundantly on potato dextrose agar. The optimum temperature for sclerotial formation was $20^{\circ}C$. Pathogenicity of the causal organism was proven according to Koch's postulate. The causal organism was identified as Botrytis cinerea based on mycological characteristics. This is the first report on gray mold of Pisum sativum caused by B. cinerea in Korea.

• Korean journal of applied entomology
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• v.42 no.1
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• pp.65-70
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• 2003

For the purpose of the protection of beneficial insects from pathogens and the development of control agent against pests, a strain of Metarhizium sp. was isolated from the infected Protaetia brevitarsis seulensis larvae in Korea. Under the scanning electron microscope, the isolate, Metarhizium sp. KMA-1, showed distinct formation of conidia on the palisade-like masse which were comprised of elongate chains and this shape is a typical feature of Metarhizium species. PCR techniques were used to identify the isolate and the primers used were designed on the basis of two kinds of rRNAs sequences, 28S rRNA and internal transcribed spacer(ITS). The specific PCR products from each primer set were amplified and the DNA sequences were determined for the similarity comparison. Sequence alignment of these fragments using GenBank database resulted in the highest homology similarity between the isolate Metarhizium sp. KMA-1 and M. anisopliae. From these results, the isolate Metarhizium sp. KMA-1 in this study was identified as M. anisopliae.

• Research in Plant Disease
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• v.10 no.2
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• pp.117-120
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• 2004

In April of 2003, the gray mold disease occurred severely on statice (Limonium shinuatum Mill. cv. Sophia) grown in the commerical farms in Seosang-myon, Hamyang-gun, Gyeongnam Province, Korea, 2003. The infected plants were started with water-soaking lesions in the stems, the leaves and the flowers became withered and discolored to gray or dark from the tip then gradually expanded to die. The conidia and mycelia of the pathogen appeared on flowers, leaves, calyx and flower stalk. The conidia were gray, I-celled, mostly ellipsoid or ovoid in shape and were 8∼20 x 6∼14 ${\mu}{\textrm}{m}$ in size. Conidiophores were 14∼34 ${\mu}{\textrm}{m}$ in size. The sclerotia were formed abundantly on potato-dextrose agar. The optimum temperature for sclerotial formation was 2$0^{\circ}C$. Pathogenicity of the causal organism was proved according to Koch's postulate. The causal organism was identified as Botrytis cinerea Persoon: Fries based on mycological characteristics. This is the first report on gray mold of statice (Limonium shinuatum) caused by Botrytis cinerea in Korea.

• Research in Plant Disease
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• v.15 no.2
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• pp.127-129
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• 2009

Gray mold caused by Botrytis cinerea occurred on Astragalus sinicus in an experimetal rice field of Gyeongsangnam-do Agricultural Research and Extension Services in Korea from 2008 to 2009. The symptoms appeared on the leaves, petiole and stems of infected plants. and then started with water-soaked, rotted and eventually died blight on plants. The colony were grayish brown and the optimum temperature for sclerotial formation was $20^{\circ}C$ on potato dextrose agar. The conidia were one celled, mostly ellipsoid or ovoid in shape, and were colorless or pale brown in color. The conidia were $7{\sim}16{\times}5{\sim}10{\mu}m$ in size and conidiophores were $14{\sim}28{\mu}m$ in length. On the basis of mycological characteristics and pathogenicity test on host plants, the fungus was identified as Botrytis cinerea Persoon: Fries.

• Mycobiology
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• v.34 no.2
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• pp.61-66
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• 2006

Chestnut blight disease caused by Cryphonectria parasitica is widely distributed throughout chestnut tree plantations in Korea. We surveyed 65 sites located at 9 provinces in South Korea, and isolated 248 virulent and 3 hypovirulent strains of chestnut blight fungus. Hypovirulent strains had dsRNA virus in the cytoplasm, which is one of the typical characteristics of hypovirulent strains. In addition, they showed more characteristics of hypovirulent strains, i.e., suppressed conidiation, reduced pigmentation in colony color, and reduced phenol oxidase activity as well as reduced pathogenicity. Hypovirulent strains, KCPH-22, KCPH-135 and KCPH-136, had a genomic dsRNA band with the molecular weight of 12.7 kb, which is the L-dsRNA of CHV1. They also had a 2.7 kb defective dsRNA band. Single conidia isolated from hypovirulent strains were cultured and various phenotypes and absence of dsRNA bands were obtained from single conidial cultures, which means that hypovirulence transmission is unstable in asexual reproduction and variations in viral heredity by asexual reproduction. Biocontrol trial using hypovirulent strains was also carried out in the chestnut tree plantations, and canker expansion in the treated trees was stopped and healed by callus formation at the margin of the canker. These results show the potentials in successful biocontrol of chestnut blight if the vegetatively compatible hypovirulent strains could be directly used around the canker formed by compatible virulent strains.

• The Plant Pathology Journal
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• v.38 no.6
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• pp.593-602
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• 2022

Anthracnose, caused by the ascomycete fungus Colletotrichum scovillei, is a destructive disease in pepper. The fungus germinates and develops an infection structure called an appressorium on the plant surface. Several signaling cascades, including cAMP-mediated signaling and mitogen-activated protein kinase (MAPK) cascades, are involved in fungal development and pathogenicity in plant pathogenic fungi, but this has not been well studied in the fruit-infecting fungus C. scovillei. Ste50 is an adaptor protein interacting with multiple upstream components to activate the MAPK cascades. Here, we characterized the CsSTE50 gene of C. scovillei, a homolog of Magnaporthe oryzae MST50 that functions in MAPK cascades, by gene knockout. The knockout mutant ΔCsste50 had pleiotropic phenotypes in development and pathogenicity. Compared with the wild-type, the mutants grew faster and produced more conidia on regular agar but were more sensitive to osmotic stress. On artificial and plant surfaces, the conidia of the mutant showed significantly reduced germination and failed to form appressoria. The mutant was completely non-pathogenic on pepper fruits with or without wounds, indicating that pre-penetration and invasive growth were both defective in the mutant. Our results show that the adaptor protein CsSTE50 plays a role in vegetative growth, conidiation, germination, appressorium formation, and pathogenicity in C. scovillei.