• Korean Journal Plant Pathology
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• v.12 no.3
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• pp.291-296
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• 1996

옥수수 유묘접종시 깜부기병이 가장 잘 발병하는 조건은 4엽기 옥수수묘를 10\ulcorner~10\ulcorner/ml 농도의 소생자 현탁액으로 경엽살포한 후 28~3$0^{\circ}C$의 습실상에서 24시간 둔 후 꺼내어 온실에 두었을 때였다. 유묘의 엽기가 이보다 어리거나 접종원 농도가 이보다 높을 때, 혹은 습실상내 처리기간이 길어지면 접종후 유묘의 이른 고사를 초래하였다. 또한 습실상의 온도가 낮아질수록 깜부기병의 발병정도도 감소하였다. 깜부기병의 발생은 소생자 현탁액의 경엽살포 및 줄기주사접종에 의해서는 가능하였지만 토양관주에 의해서는 발병하지 않았다. 소생자 현탁액은 별도의 영양원의 첨가 없이도 발병을 잘 유도하였다. 동포자 현탁액을 직접 경엽살포하거나 줄기주사접종하여도 발병하였으나 소생자 현탁액접종에 비하여 발병정도가 현저히 낮았다.

• Korean Journal Plant Pathology
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• v.12 no.3
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• pp.297-301
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• 1996

옥수수 깜부기병균에 대한 살균제 활성검정시 실내 검정과 온실 유묘검정과의 상관정도를 조사하기 위하여 5가지 살균제를 공시하여 실내와 온실에서 깜부기병균에 대한 억제효과를 비교하였다. 실내검정방법으로 사용한 최소생육억제농도법, 저지원법, 소생자발아검정법의 결과는 모두 온실유묘검정에서 얻어진 결과와 상관이 높았으며 특히 저지원법은 유묘검정결과와 매우 높은 상관관계를 보였다. 따라서 저지원법과 같은 실내검정방법은 대량의 활성검정시 간이검정방법으로 유용하게 이용될 수 있으리라 생각된다.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.142-146
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• 1996

옥수수 깜부기병균 Ustilago maydis 동포자를 풍건한 후 모래나 silica gel을 보존매체로 해서 4$^{\circ}C$나 그 이하 온도에서 24개월 두었을 때 동포자 생존율은 40~45%였다. 동포자는 28$^{\circ}C$ PDA상에서 쉽게 발아하여 많은 소생자를 형성하였다. U. maydis 동포자로부터 소생자 형성의 최적배지는 corn meal broth였고, carrot broth와 potato-dextrose broth의 순으로 좋았다. 소생자 형성에 가장 적합한 조건은 온도 28~3$0^{\circ}C$, pH5~7이었다. 소생자 형성은 암조건에서 보다 좋았다.

• The Korean Journal of Mycology
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• v.39 no.3
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• pp.249-253
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• 2011

Cetecol has been known as a component of melanin in teliospores of the corn smut fungus Ustilago maydis. Its metabolic precursor has been assumed to be benzoic acid but it has not been proven yet. This study was carried out to verify the synthesis of benzoic acid and to chase its metabolic origin in U. maydis. For this aim, the catabolic process of phenylalanine was investigated by culturing the fungus in the complete medium containing L-$^{14}C$-phenylalanine and $^{14}C$-trans-cinnamic acid. We detected trans-cinnamic acid, benzoic acid, 4-hydroxybenzoic acid and hydroxybenzoic acid derivatives from the extracts of the fungus cells and cultural filtrates by thin layered chromatography analysis. We also observed that the fungus could completely catabolize L-$^{14}C$-phenylalanine and produce $^{14}CO_2$ in the air. Conclusively, this study provided an evidence that U. maydis could produce benzoic acid through catabolic process of phenylalanine.

• Korean Journal of Microbiology
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• v.31 no.3
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• pp.184-188
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• 1993

Novel Ustilagomaydis strains, designated as SH1 to 14 containing new types of ds RNA segments, are identified from corn smut in Korea. Among 14 isolates, 7 isolates appear to posses virus particles and the other isolates may contain dsRNA as a plasmid form. The pattern of dsRNA is highly diverse form a typical P-type containing one or more of H, M, and L dsRNAs to the one containing one or move M dsRNAs. It is likely that the strains containing H dsRNA posses virus particles which were confirmed by sucrose density gradient followed with different range of specificity and the activity of the strain (SH14) is stronger than A4 toxin. The sensitivity of 14 isolates is also very diverse and two strains (SH10, SH11) appear tobe universal sensitve strains against 5 tested toxin samples.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.147-149
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• 1996

Ustilago maydis의 소생자는 물한천배지에서 접종후 8시간 후에 98% 이상 발아하였다. PDA를 포함한 기타 영야배지에서의 발아율도 이와 비슷하였다. 소생자 발아에 가장 적당한 온도는 3$0^{\circ}C$였으며 $25^{\circ}C$나 35$^{\circ}C$순으로 양호하였으나 2$0^{\circ}C$나 그 이하의 저온에서는 발아율이 급격히 떨어졌다. 소생자는 pH 5~9의 범위에서 80%이상 발아하였으나 최적 pH는 6~7이었다. 광조사는 소생자 발아에 큰 영향을 미치지 못하였다. 소생자는 자유수분(RH 100%)하에서 24시간 후 81%가 발아하였으나 상대습도가 93%나 그 이하에서는 발아율이 19~34%였다. 이 실험결과는 소생자 발아에 가장 큰 영향을 미치는 환경요인은 온도와 습도였으며 우리나라 기후조건에서 소생자는 7~8월의 한여름철 장마기간 동안 왕성하게 발아할 수 있음을 뜻하고 있다.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.60-60
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• 2015

Hybrid histidine kinase is a part of two-component system that is required for various stress responses and pathogenesis of pathogenic fungi. In the present study, Tco1, a homologue of human pathogen Cryptococcus neoformans Tco1 encoding a hybrid histidine kinase, was identified in corn smut pathogen Ustilago maydis by bioinformatic analysis. To explore the role of Tco1 in the virulence of U. maydis, mutants in which the tco1 gene was partially deleted were constructed by allelic exchange. The U. maydis tco1 mutants did show unaltered growth rate on axenic medium but were unable to produce conjugation tubes and develop fuzzy filaments, resulting in impaired mating of compatible strains. The expression levels of prf1, pra1, and mfa1 which are involved in the pheromone pathway significantly decreased in the tco1 mutants. In inoculation tests to host, the tco1 mutants showed significantly reduced ability in the production of anthocyanin pigments and tumor development on maize leaves. Overall, the combined results indicated that Tco1 plays important roles in sexual development and virulence of U. maydis by regulating the expression of the genes involved in the pheromone pathway.

• The Plant Pathology Journal
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• v.27 no.1
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• pp.20-25
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• 2011

Gibberella zeae (anamorph: Fusarium graminearum), a homothallic (self-ferile) ascomycete with ubiquitous geographic distribution, causes serious diseases in several cereal crops. Ascospores (sexual spores) produced by this fungal pathogen have been suggested as the main source of primary inoculum in disease development. Here, we report the function of a gene designated GzRUM1, which is essential for ascospore formation in G. zeae. The deduced product of GzRUM1 showed significant similarities to the human retinoblastoma (tumor suppressor) binding protein 2 and a transcriptional repressor, Rum1 in the corn smut fungus (Ustilago maydis). The transcript of GzRUM1 was detected during the both vegetative and sexual stages, but was more highly accumulated during the latter stage. In addition, no GzRUM1 transcript was detected in a G. zeae strain lacking a mating-type gene (MAT1-2), a master regulator for sexual development in G. zeae. Targeted deletion of GzRUM1 caused no dramatic changes in several traits except ascospore formation. The ${\Delta}$GzRUM1 strain produced perithecia (sexual fruit bodies) but not asci nor ascospores within them. This specific defect leading to an arrest in ascospore development suggests that GzRUM1, as Rum1 in U. maydis, functions as a transcriptional regulator during sexual reproduction in G. zeae.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.3
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• pp.233-238
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• 2006

This study was conducted to evaluate growth characteristics, yield and feed value of newly bred domestic silage corn hybrids compared to foreign imported corn hybrid. Days to silking were $78{\sim}86$ days and longer than that of P3394 (Control). Kwangpyeongok, Cheonganok, and Cheongsaok were resistant to lodging. Such trait of stay-green of Kwanganok, Kwangpyeongok, Cheonganok, Cheongsaok, and Suwon159 was not different from that of P3394. Duruok, Kwangpyeongok, and Suwon159 were more resistant to Bipolaris maydis (southern corn leaf blight) than P3394. All of the silage corn hybrids were resistant to Exserohilum turcicum (northern corn leaf blight) and Smut. Ear ratios to total dry matter (%) of Cheonganok was similar to P3394. Ear lengths of domestic hybrids were similar or longer than that of P3394. Dry matter yield of domestic hybrids except Suwon19 and Jangdaok were similar to that of P3394. Total digestible nutrient (TDN) yields, Duruok, Kwangpyeongok, Cheonganok, and Cheongsaok were similar to P3394, but Kwanganok, Suwon19, Jangdaok and Suwon159 were lower than P3394. Acid detergent fiber(ADF), Suwon19 was lowest among all hybrids, and all hybrids except Suwon19 had values ranging from 44.7 to 49.0%, similarly with P3394. Neutral detergent fiber (NDF) values of the hybrids were similar to that of P3394, and ranged from 68.1 to 72.8%, except for Duruok which was lowest. Relative feed values (RFV) of Duruok, Kwangpyeongok, Cheonganok, Jangdaok, and Suwon159 had values ranging from 71.0 to 75.7 and were not significantly different from P3394. ADF was significantly negatively correlated with number of days to silking, number of days to maturity, and fresh matter yield, but was significantly positively correlated with resistance to corn borer. RFV showed a significantly positive correlations with no. of days to maturity and fresh matter yield, but significantly negative correlation with resistance to European corn borer. Therefore, indices for evaluation of feed value as well as production were important to select corn hybrids for silage. It is concluded that domestic hybrids tested in this study have high feed value as well as high production similar to those of imported corn hybrid.

• Korean Journal of Organic Agriculture
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• v.18 no.1
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• pp.93-104
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• 2010

This study was conducted screening of the population densities of fungal pathogens and insect and observed the disease symptoms on the organic sweet corn seed producing field from 2008 to 2009. The dissemination spores, Alternaria sp., Cladosporium sp., Helminthosporium sp., Pyricularia sp., Collectotrichum sp., and Bipolaris sp., were detected and the three fungal spores from the front were observed for whole growth stage. Seed and seedling diseases were shown as the rotted seed and damping-off seedling caused by Penicillium sp. and Rhizoctonia sp.. The larva of Black cutworm cut down the root crown of seedlings. The damaged plants were ranged from 14% to 16%. On the Oriental corn borer, the population densities and the percentage of damaged plants were showed a low difference between two sweet corn varieties. The population densities of Oriental corn borer were scored as from 3.5 to 20.5 in 2008 and from 0.5 to 6 in 2009. Also the percentage of damaged plants were significantly increased until harvesting stage and was recorded from 7.5% to 21% in 2008 and from 1% to 46% in 2009. On the Corn leaf blight, the percentage of diseased plant were scored from 7% to 34% in 2008. The first occurrence of date was after June 18, and the percentage of diseased plant was continuously increased after August 21 and the values of diseased plants was ranged from 56% to 69% in 2009. On common smut, the percentage of diseased plant was recorded from 5% to 15% in 2008, and the first occurrence date were delayed as 17 days (July 17) and were showed less than 8% of diseased plants in 2009. Corn Southern Leaf spot was scored as average 11% at early stage and showed high score as 62% at September 19 in 2008. In 2009, the first occurrence date were advanced about 20 days (after June 8), and continuously increased up to 86% in 2009.