• The Plant Pathology Journal
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• 제17권5호
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• pp.281-289
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• 2001

We analyzed 88 strains of Gibberella fujikuroi (Analmorph: Fusarium section Liseola) from maize in Korea for mating population, mating type, fumonisin production vegetative compatibility, and random amplified polymorphic DNA (RAPD) patterns. We found 50 strains that were MATA-2, 22 that were MATA-1, 1 that was MATD-1, and 15 that were not reproducibly fertile with any of the mating type testers. Of the 50 MATA-2, 15 were female fertile, while 10 of the 22 MATA-1 strains were female fertile. A total of 1,138 nitrate non-utilizing (nit) mutants were recovered from a total of 88 strains. These strains were grouped into 39 vegetative compatability groups (VCGs) by demonstrating heterokaryosis between nit mutants. A single maize ear could be infected by more than one VCG of F. moniliforme. RAPD analysis measured genetic diversity among 63 strains of F. moniliforme. Several VCGs were distinguished by RAPD fingerprinting patterns. Most strains produced significant levels of fumonisins. However, 6 MATA-2 strains from a single VCG produced higher levels of fumonisin $\textrm{B}_3$ than that of fumonisin $\textrm{B}_1$ or $\textrm{B}_2$. From these data, we concluded that most Korean strains of F. moniliforme associated with maize belonged to mating population A and produced significant levels of fumonisins. Futhermore, RAPD analysis could differentiate strains associated with different VCGs.

• Journal of Microbiology and Biotechnology
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• 제15권1호
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• pp.22-28
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• 2005

Gibberellins (GAs) play important roles in plant growth and development. Fifty-four fungi were isolated from the roots of 4 kinds of Sesamum indicum plants, and the production of GAs was spectrophotometrically examined. The number of GA-producing fungi was two strains from S. indicum, four strains from Gold S. indicum, and five strains from Brown S. indicum. Eleven fungi with GAs-producing activity were incubated for seven days in 40 ml of Czapek's liquid medium at $25^{\circ}C$ and 120 rpm, and the amount of each GA in the medium was measured by gas chromatographymass spectrometery (GC-MS). Penicillium commune KNU5379 produced more $GA_3$, $GA_4$, and $GA_7$ than Gibberella fujikuroi, Fusarium proliferatum, and Neurospora crassa which are known as GAs-producing fungi. GAs-producing activity of the P. commune KNU5379 was shown to produce 71.69 ng of $GA_1$, 252.42 ng of $GA_3$, 612.00 ng of $GA_4$, 259.00 ng of $GA_7$, and 202.69 ng of $GA_9$ in 25 ml of liquid medium. Bioassay of culture fluid of GA-producing fungi was also performed on rice sprout.

• Journal of Microbiology and Biotechnology
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• 제30권5호
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• pp.668-680
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• 2020

Bacillus velezensis is an important plant growth-promoting rhizobacterium with immense potential in agriculture development. In the present study, Bacillus velezensis Lle-9 was isolated from the bulbs of Lilium leucanthum. The isolated strain showed antifungal activities against plant pathogens like Botryosphaeria dothidea, Fusarium oxysporum, Botrytis cinerea and Fusarium fujikuroi. The highest percentage of growth inhibition i.e., 68.56±2.35% was observed against Fusarium oxysporum followed by 63.12 ± 2.83%, 61.67 ± 3.39% and 55.82 ± 2.76% against Botrytis cinerea, Botryosphaeria dothidea, and Fusarium fujikuroi, respectively. The ethyl acetate fraction revealed a number of bioactive compounds and several were identified as antimicrobial agents such as diketopiperazines, cyclo-peptides, linear peptides, latrunculin A, 5α-hydroxy-6-ketocholesterol, (R)-S-lactoylglutathione, triamterene, rubiadin, moxifloxacin, 9-hydroxy-5Z,7E,11Z,14Z-eicosatetraenoic acid, D-erythro-C18-Sphingosine, citrinin, and 2-arachidonoyllysophosphatidylcholine. The presence of these antimicrobial compounds in the bacterial culture might have contributed to the antifungal activities of the isolated B. velezensis Lle-9. The strain showed plant growth-promoting traits such as production of organic acids, ACC deaminase, indole-3-acetic acid (IAA), siderophores, and nitrogen fixation and phosphate solubilization. IAA production was accelerated with application of exogenous tryptophan concentrations in the medium. Further, the lily plants upon inoculation with Lle-9 exhibited improved vegetative growth, more flowering shoots and longer roots than control plants under greenhouse condition. The isolated B. velezensis strain Lle-9 possessed broad-spectrum antifungal activities and multiple plant growth-promoting traits and thus may play an important role in promoting sustainable agriculture. This strain could be developed and applied in field experiments in order to promote plant growth and control disease pathogens.

• The Plant Pathology Journal
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• 제17권5호
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• pp.276-280
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• 2001

Fusarium isolates of Gibberella fujikuroi species complex were obtained from sorghum grown in five provinces of Korea in 1996 and 1997. These isolates were characterized based on their mating behavior, mycotoxin production, and vegetative compatibility. Only three mating populations (A, D, and F) were recovered from a total of 155 isolates examined. The relative frequency of the mating populations was significantly different: F was predominant (80%), while D and A were observed at low frequencies of 9% and 3%, respectively. Female fertile isolates were more common within F (44 our of 124) than D (2 out of 14), while none of the five A isolates were female fertile. The inbreeding effective population sizes ($\textrm{N}_e$)for mating type and male/hermaphrodite ratios in mating populations A and D produced significant amounts of fumonisins, while F isolates produced none or only traces of fumonisin B$_1$. In contrast. F isolates produced higher amounts of moniliformin (average of 3,820 ppm) than A and D isolates (averages of 77 and 1,819 ppm, respectively). Fifty-one isolates were tested for vegetative compatibility using nitrogen non-utilization mutants of each isolate, and 44 vegetative compatibility groups (VCGs) were identified. A single VC type (VC1) was found in all of the five A isolates examined. Six of the D isolates examined consisted of three VC types: two for VC2, two for VC3, and the rest for VC4. All of the F isolates tested were incompatible in every combination and , thus, each constituted a unique VCG.

• 식물병연구
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• 제25권4호
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• pp.157-163
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• 2019

본 연구에서는 귀리에서 독성곰팡이 발생현황을 평가하기 위해 2017년 2018년 4월부터 6월까지 귀리 재배지 강진, 정읍을 정기적으로 모니터링 하였다. 총 745개의 곰팡이 균주를 형태학적 방법으로 분리한 후 마커 유전자 염기서열을 분석하여 동정하였다. 분리된 곰팡이의 약 92%가 Fusarium속 균주였고, Penicillium속(5.9%)과 Aspergillus속(2.1%) 순으로 분리되었다. Fusarium속 균주의 대부분이 F. asiaticum (83.1%)이었고, F. incarnatum (5.4%), F. proliferatum (3.5%), F. fujikuroi (2.8%), F. tricinctum species complex (FTSC) 11 (1.5%), F. graminearum (1.0%) 순으로 많이 분리되었다. F. asiaticum의 약 97%가 nivalenol 독소화학형이 있었고, 3-acetyl deoxynivalenol (3.2%) 독소화학형과 15-acetyl deoxynivalenol (0.4%) 독소화학형도 발견되었다. 선발된 Fusarium 균들의 병원성 실험결과 F. asiaticum이 실험에 사용된 모든 식물체에서 다양한 범위의 병원성을 나타내었다. 병증이 있는 종실에서 분리된 F. graminearum and FTSC 11 균주들은 쌀귀리에서 강한 병원성을 나타내었다. 또한 FTSC 11 균주를 제외한 모든 균주들이 쌀배지에서 nivalenol (0.2-7.6 ㎍/g), deoxynivalenol (0.03-6.1 ㎍/g), zearalenone (0.1-27.0 ㎍/g)을 생성하였다. 본 연구는 국내에서는 처음 보고되는 F. asiaticum에 의한 귀리의 붉은 곰팡이병 사례이다. 본 연구의 결과는 밀, 보리, 벼와 마찬가지로 F. asiaticum이국내귀리에서우점종임을보여준다.

• 한국균학회지
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• 제38권1호
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• pp.75-79
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• 2010

2006년부터 2007년까지 벼키다리병균을 수집하여 25개 균주의 prochloraz와 benomyl + thiram에 대한 약제저항성을 검정하였다. 공시한 균주 중, 대부분의 균주가 감수성이었으나 prochloraz에 대한 약제저항성 균주는 6개로 조사되었고, benomyl + thiram에 대해서는 3개 균주가 저항성을 나타내었다. 이 중 CF245, CF249, CF337은 공시약제 모두에 대해 저항성이었다. 감수성 균주간 교배 및 감수성, 저항성 균주간 교배를 통해 얻어진 후대균주를 분리하여 온도별 균사 생장율과 약제에 대한 반응을 조사하였다. 온도별 균사 생장은 감수성 균주간 교배(CF202 $\times$ CF232)에서는 모균주와 비슷하였으나, 감수성과 저항성 균주간 교배(CF179 $\times$ CF337)에서는 모균주에 비해 후대균주의 균사생장이 빠른 것으로 나타났다. 공시약제에 대한 반응은 약제에 따라 모균주와 다른 양상을 나타내었다. Prochloraz의 경우, 감수성균주인 CF202 $\times$ CF232의 후대균주에서 감수성과 저항성의 분포비율이 86 : 14로 나타났고, 감수성과 저항성 균주인 CF179 $\times$ CF337의 후대균주에서는 78 : 22로 나타났다. Benomyl + thiram의 경우, CF202 $\times$ CF232의 후대균주는 모두 감수성인 것으로 나타났으며, CF179 $\times$ CF337의 후대균주에서는 35 : 65로 조사되었다.

• 식물병연구
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• 제19권4호
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• pp.254-258
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• 2013

후자린산(FA)는 Fusarium 속 균이 생성하는 독소로서 다른 곰팡이독소보다 독성은 낮으나 다른 독소와 중복 오염시 전체 독성을 증진시키는 것으로 알려졌다. 현재까지 FA 생합성 관련 효소나 유전자가 Fusarium oxysporum에서 밝혀지지 않았기 때문에 본 연구에서는 관련 생합성 유전자의 발굴을 위해 제한효소를 통한 무작위 삽입 형질전환방법인 REMI를 이용하여 FA 생성 F. oxysporum 균주의 생합성유전자의 결손을 시도하였다. F. oxysporum 균주 2주를 대상으로 REMI를 시도한 결과, 평균 3.2주 ($1{\mu}g$ DNA 당)의 효율로 7,100주 이상의 형질전환체를 육성하였다. FA 미생성 형질전환체를 스크리닝 하기 위해 FA가 함유된 배양액에서 다양한 식물종자의 발아여부를 조사한 결과, 11종의 종자 중 가장 감수성인 배추종자를 선발하였다. 각 형질전환체는 Czapek-Dox broth에서 3주간 배양한 후 배양여액을 배추종자의 발아여부 검정에 사용하였다. 검정결과 총 5,000여 주의 REMI 형질전환체 중 53주의 배양여액에서 종자가 발아하지 않아, 이들을 FA 미(저) 생성 추정 형질전환체로 선발하였다. 이중 26주의 FA 생성량을 HPLC로 분석한 결과, 2주의 형질전환체에서 모균주 생성량의 1% 이하의 FA가 검출되었다. 이 중 형질전환체 1주로부터 REMI 벡터 삽입 부위 게놈 DNA의 염기서열(252 bp)을 확보하였으며, 이 부위는 F. fujikuroi의 미동정 게놈부위와 93% 유사성이 있음을 확인하였다. 이 부위의 FA생성 관련성 증명을 위해서는 추후 연구가 필요하다.

• The Plant Pathology Journal
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• 제32권3호
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• pp.228-241
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• 2016

In our previous study, we reported that a novel endophytic bacterium Bacillus oryzicola YC7007 has suppressed bacterial diseases of rice via induced systemic resistance and antibiotic production. This endophytic strain, B. oryzicola YC7007 was used as a biological control agent against bakanae disease of rice caused by Fusarium fujikuroi, and its mechanism of interaction with the pathogen and the rice was further elucidated. Root drenching with B. oryzicola YC7007 suspension reduced the disease severity of bakanae significantly when compared with the untreated controls. The treatments of B. oryzicola YC7007 suspension ($2.0{\times}10^7cfu/ml$) to the rice rhizosphere reduced bakanae severity by 46-78% in pots and nursery box tests containing autoclaved and non-autoclaved soils. Moreover, in the detached rice leaves bioassay, the development of necrotic lesion and mycelial expansion of F. fujikuroi were inhibited significantly by spraying the culture filtrate of B. oryzicola YC7007. Drenching of ethyl acetate extracts of the culture filtrate to the rhizosphere of rice seedlings also reduced the bakanae disease severity in the plant culture dish tests. With the root drenching of B. oryzicola YC7007 suspension, the accumulation of hydrogen peroxide was observed at an early stage of rice seedlings, and a hormonal defense was elicited with and without pathogen inoculation. Our results showed that the strain B. oryzicola YC7007 had a good biocontrol activity against the bakanae disease of rice by direct inhibition, and was also capable of inducing systemic resistance against the pathogen via primed induction of the jasmonic acid pathway.

• 식물병연구
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• 제14권3호
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• pp.176-181
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• 2008

본 연구는 키다리병에 심하게 감염된 종자를 온탕침법과 prochloraz 유제로 종자소독 시 그 효과가 떨어지는 원인을 규명하기 위해 시행하였다. 키다리병이 발병한 포장에서 수확한 종자의 경우 병원균이 벼 종자의 배와 배유 안쪽까지 감염되어 있었다. $60^{\circ}C$에서 10분 동안 온탕 소독한 종자의 경우 종피 표면의 균사는 파괴되어 비정상적인 반면 배 주피 안쪽에 존재하는 균사는 정상적인 형태로 존재하였다. 포자는 종피 표면에서 비정상적인 포자와 정상적인 포자를 모두 확인하였다. prochloraz 유제로 $30^{\circ}C$ 24시간 침지소독 한 경우 종피의 균사는 완전히 파괴되었으나 포자는 정상과 비정상 포자 모두 확인할 수 있었다. 이러한 결과를 통해 온탕소독의 경우 종피 같은 물리적 한계로 인해 고열이 병원균에 전달되지 못하고, prochloraz의 경우 병원균 포자를 완전히 사멸시키기 못하기 때문에 종자소독 효과가 떨어짐을 알 수 있었다.

• Mycobiology
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• 제41권2호
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• pp.100-107
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• 2013

Diverse fungi are present in Korean traditional meju and they are known to play an important role in fermented soybean products. To determine the origin of the fungi in meju, we examined the mycoflora of soybeans from 10 traditional meju factories. The samples were untreated or treated with sodium hypochlorite, and placed on malt extract agar (MEA), dichloran 18% glycerol agar (DG18), and dichloran rose bengal chloramphenicol agar (DRBC) medium. A total of 794 fungal strains were isolated and they were identified as 41 genera and 86 species. From sodium hypochlorite untreated soybeans, the genera, Cladosporium (55%), Eurotium (51%), Fusarium (33%), Penicillium (22%), and Aspergillus (exclusion of Eurotium) (20%), were mainly isolated, and Eurotium herbariorum (22%), Eurotium repens (18%), Cladosporium tenuissimum (18%), F. fujikuroi (18%), Aspergillus oryzae/flavus (7%), and Penicillium steckii (6%) were the predominant species. In case of sodium hypochloritetreated soybeans, Eurotium (31%) and Cladosporium (5%) were frequently isolated, but Aspergillus (excluding Eurotium), Penicillium and Fusarium which were frequently isolated from untreated soybeans, were rarely isolated. Eurotium herbariorum (21%), Eurotium repens (8%), and Cladosporium tenuissimum (3%) were the predominant species. Of the 41 genera and 86 species isolated from soybeans, 13 genera and 33 species were also found in meju. These results suggest that the fungi on soybeans may influence the mycoflora of meju.