• The Plant Pathology Journal
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• 제18권3호
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• pp.161-164
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• 2002

Colletotrichum musae was isolated from dark-brown anthracnose lesions on commercial banana (Musa sapientum L.) to establish the causal agent of the symptom. The fungus grew fast and produced white aerial mycelium on PDA. Acervuli developed abundantly on culture plates after incubation for 10 days at $25^{\circ}C$. Pinkish conidial masses were produced on the acervuli, which mostly coalesced together, Conidia were aseptate, hyaline, straight, ellipsoid to globose, and 14.5$\times$6.9 $\mu\textrm{m}$ in size. Black, clavate, round, or irregular-shaped appressoria measuring 8.8$\times$6.8 $\mu\textrm{m}$ were readily formed from germ tubes. Setae-like structures were not found either on the lesion or on the cultures. Sclerotia were also absent. Among the media, PDA medium was the best for mycelial growth. The optimum temperature for mycelial growth was $28^{\circ}C$, while the optimum pH ranged from pH 5.5 to 6.5. The isolates of C musae caused black necrotic lesions on banana fruits by needle-wound inoculation, and orange-colored spore masses were produced on the lesions. The fungus also caused discoloration on apple fruits inoculated.

• 한국식물병리학회지
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• 제14권5호
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• pp.413-417
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• 1998

Magnaporthe grisea, the casual agent of rice blast, requires formation of an appressorium, a dome-shaped and well melanized infection structure, to penetrate its host. Environmental cues that induce appressorium formation include hydrophobicity and hardness of contact surface and chemicals from its host. Artificial surfaces are widely used to induce appressorium formation, but frequencies of appressorium induction are not always consistent. To understand variable induction of appressorium formation in M. grisea, several factors were tested on GelBond. High levels of appressorium formation were induced over a wide range of temperature (20~3$0^{\circ}C$) and pH (4~7). spore age up to 3-week-old did not significantly affect appressorium formation, but only a few apressoria on GelBond. However, adenosine specifically inhibited appressorium formation. Adenosine inhibition of appressorium formation was restored by exogenous addition of cAMP. Germ tube tips of M. grisea maintained the ability to differentiate appressoria by chemical inducers on GelBond at least up to 16 h after conidia germination. These results suggest that environmental factors have little effect on the variable induction of appressorium formation on the artificial surface in M. grisea.

• 한국식물병리학회지
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• 제14권6호
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• pp.651-653
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• 1998

A destructive anthracnose of safflower has severely occurred at Kyeongsangnam-do Agricultural Research and Extention Services in 1998. Incidence of the disease surveyed at 12 fields in Chinju, Sanchong and Hamyang was ranged fro 55.7 to 85.4%. Small irregular yellowish to brown spots appeared on all parts of the plant at initial infection stage and the spots enlarged or united into larger irregular to cylindrical black lesions with hollows. Above portions of infected stems were often blighted and pink colored conidial masses were colonized on the lesions. The causal fungus consistently isolated from the infected tissues were identified as Colletotrichum acutatum by following characteristics. The fungus grew well on PDA at 15~3$0^{\circ}C$ developing apricot to salmon color. Conidia were single-celled, colorless, fusiform and bisectioned and measured as 8~18$\times$3~5 ${\mu}{\textrm}{m}$. Brownish appressoria were cylindrical or ovate and sized as 5~10$\times$4~8 ${\mu}{\textrm}{m}$. Optimum temperature for growth and germination of conidia was recorded at $25^{\circ}C$ and at least 6 hours were required for infection to the host plants. Over 90% conidia were germinated and all plants were infected by artificial inoculation by 24 hours at $25^{\circ}C$. This is the first report of safflower anthracnose caused by C. acutatum in Korea.

• The Plant Pathology Journal
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• 제19권1호
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• pp.34-42
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• 2003

The ascomycete Magnaporthe grisea is a pathogen of rice blast and is known to form specialized infection structures called appressoria for successful infection into host cells. To understand the molecular mechanism underlying infection process, appressorium-related genes were identified through global approaches including EST sequencing, differential hybridization, and sup-pression subtractive hybridization. EST database was generated on >2,000 cDNA clones randomly selected from appressorium stage cDNA library. Large number of ESTs showed homology to known proteins possibly involved in infection-related cellular development (attachment, germination, appressorium formation, and colonization) of rice blast fungus. The 1051 ESTs showing significant homology to known genes were assigned to 11 functional categories. Differential hybridization and suppression subtractive hybridization were applied to identify genes showing an appressorium stage specific expression pattern. A number of genes were selected as up-regulated during appressorium formation compared with the vegetative growing stage. Clones from various cDNA libraries constructed in different developmental stages were arrayed on slide glass for further expression profiling study. functional characterization of genes identified from these global approaches may lead to a better understand-ing of the infection process of this devastating plant disease, and the development of novel ways to protect host plant.

• Journal of Microbiology and Biotechnology
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• 제10권6호
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• pp.805-810
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• 2000

An antifungal protein antagonistic to the rice blast fungus, Pyricularia oryzae was purified from Paenibacillus macerans PM-1 by ammonium sulfate fractionation, Q Sepharose Fast Flow column chromatography, Phenyl Sepharose CL-4B column chromatography and Superose 12 gen filtration. An apparent molecular mass of the purified antifungal protein was determined as 8 kDa by SDS-PAGE and 9 kDa by analytical gel filtration, respectively, suggesting that the purified protein is a monomer. The antifungal protein was stable at pH range from 7-12 and up to $100^{\circ}C$. The protein was also stable at 0.1-1% Tween 20 and Triton X-100. The N-terminal amino acid sequence of the antifungal protein was Thr-Glu-Leu-Pro-Leu-Gly-Ile-Val-Met-Asp-Lys-Tyr-Thr-Asp-Ala-Phe-Lys-Phe-Asp-Met-Phe. Comparison of the determined sequence with other peptide and DNA sequences did not reveal homology at all. Therefore, the purified antifungal protein was speculated to be a novel protein. The condidial germination in vitro of P. oryzae KJ301:93-39 by the purified protein ($5.9{\mu} g/ml$) was limited to $9{\pm}3.2%$ only, compared with $69{\pm}2.4%$ of the control. Ungerminated conidia were swollen at basa and mid cell by the purified protein. In vivo bioassay for inhibition of conidial germination of P. oryzae KJ 301, one of the most predominating racesin Korea. the purified protein ($5.9{\mu} g/ml$)strongly inhibited the conidial germination. The conidia, even though germinated, could not develop any further to produce appressoria efficiently.

• The Plant Pathology Journal
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• 제16권4호
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• pp.242-245
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• 2000

In 1999 and 2000, a rot of graft-cacti including Hylocereus trigonus (three-angled cactus), Gymnocalycium mihanovichii, and Chamaecereus silvestrii occurred in several greenhouses in major cactus-growing areas of Korea. Typical symptoms included a moist, light brown rot or a watery rot of the stems. A Colletotrichum sp. was isolated from the lesions. The fungus formed dark gray, dense or floccose colonies on potato dextrose agar, frequently forming many light pink acervuli often surrounded with setae. The hyaline, cylindrical conidia were one-celled with round ends. Appressoria were mostly semicircular or clavate. Thin-walled asci contained eight, one-celled, hyaline ascospores (biseriate in ascus). Ascopspores were strainht or curved, ellipsoidal or subcylindrical. Based on these characteristics, the fungus was identified as Glomerlla cingulata (anamorph : C. gloeosporioides). Wound inoculation of basal stems of the cactus by the mycelial plugs or conidia produced symptoms identical to those described above. Various cactus species were compared in susceptibility using stem disc inoculation. Cereus tetragonus, Eriocereus jusbertii, Myrtillocactus geomentrizans, and three-angled cacti from Mexico and Taiwan were susceptible, but C. peruvianus (Peruvian apple cactus) and Harrisia tortuosa not. This is the first report of G. cingulata causing stem rot of graft-cactus in Korea.

• 한국식물병리학회지
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• 제2권3호
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• pp.185-192
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• 1986

분생포자는 발아관의 수에 따라 포자내에 격막이 형성된다. 저항성 품종(금장 2호, 홍일품)과 감수성 품종(하늘초, 새고추) 간의 부착기 형성율은 큰 차이가 없었고 부착기의 모양은 엔형, 타엔형 및 성장체 등 다양하며 접종 12시간에서 그 형성율은 최고에 달했다. 접종 24시간에 저항성 품종의 잎과 열매에서는 과민성인 작은 갈색병반이 관찰되면서 표피하 조직세포내에 심한 원형질분리가 일어났으나 감수성 품종에서는 시간의 경과에 따라 큰 병반으로 급속히 진전 확대되었고 시간이 경과함에 따라 균사가 하부조직으로 확산되었고 분생자시 및 강모의 출현은 접종 96시간 후에 관찰되었다. 감염종자의 종피는 심하게 붕괴되었을 뿐만 아니라 침입균사도 관찰되었고 배유와 배는 심한 원형질분리를 일으켰다.

• 한국균학회지
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• 제25권1호통권80호
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• pp.30-34
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• 1997

온주밀감의 병든 잎으로부터 분리된 분생포자세대와 병들어 죽은 가지로부터 분리된 유성세대의 형태학적 특정을 토대로 감귤 탄저병의 병원균은 Glomerella cingulata(분생포자 세대 Colletotrichum gloeosporioides)로 분리 동정되었다. 감귤 탄저병균은 온주밀감, 유자, 하귤 등의 잎에 상처 접종에 의해서 감염을 일으켰고, 균사 생장 및 분생포자 형성의 적온은 각각 $25{\sim}30^{\circ}C$범위였다. 잎과 가지에서 분리된 감귤 탄저병균의 균총의 생장 속도와 색, 분생포자와 부착기의 형태와 크기 등과 같은 특징들은 감귤류 저장병에 관여하는 FGG strain의 특징과 유사하였지만, 일부 형태 및 병원학적 특징이 FGG strain과 일치하지 않아 다른 strain일 가능성도 배제할 수 없다.

• The Plant Pathology Journal
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• 제35권6호
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• pp.564-574
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• 2019

Like many fungal pathogens, the conidium and appressorium play key roles during polycyclic dissemination and infection of Magnaporthe oryzae. Ran-binding protein microtubule-organizing center (RanBPM) is a highly conserved nucleocytoplasmic protein. In animalia, RanBPM has been implicated in apoptosis, cell morphology, and transcription. However, the functional roles of RanBPM, encoded by MGG_00753 (named MoRBP9) in M. oryzae, have not been elucidated. Here, the deletion mutant ΔMorbp9 for MoRBP9 was generated via homologous recombination to investigate the functions of this gene. The ΔMorbp9 exhibited normal conidial germination and vegetative growth but dramatically reduced conidiation compared with the wild type, suggesting that MoRBP9 is involved in conidial production. ΔMorbp9 conidia failed to produce appressoria on hydrophobic surfaces, whereas ΔMorbp9 still developed aberrantly shaped appressorium-like structures at hyphal tips on the same surface, suggesting that MoRBP9 is involved in the morphology of appressorium-like structures from hyphal tips and is critical for development of appressorium from germ tubes. Taken together, our results indicated that MoRBP9 played a pleiotropic role in polycyclic dissemination and infection-related morphogenesis of M. oryzae.

• 식물병연구
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• 제8권4호
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• pp.224-227
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• 2002

실내 장식용 드라세나 산데리아의 줄기에 발생한 괴사 병징으로부터 탄저병원균을 확인하였다. 분생자층 위에 분생포자, 강모 및 자낭각이 관찰되었다 분생포자는 무색, 단포, 정부는 약간 둥글고 기부는 굵고 원통형 또는 약간 타원형으로 크기는 12.5-17.5 $\mu\textrm{m}$였다. 강모는 격막이 1~4 개 존재하며, 기부세포가 특징적으로 팽대되고 크기는 200 $\mu\textrm{m}$였다 부착기는 암갈색, 난형으로 크기는 5-12.5 $\mu\textrm{m}$이며, 괴사된 줄기상의 자낭각은 구형, 암갈색 또는 검은색으로 크기는 85-300 $\mu\textrm{m}$, 자낭은 곤봉형 또는 원통형이며 크기는 50-62.5$\times$8-10 $\mu\textrm{m}$로서 8개의 자낭포자를 형성하였다. 자낭포자는 타원형 또는 굽은 방추형이었다. 이 균의 불완전세대의 특징을 C. musae와 C. lindemuthianum과 비교하여 Glomerella cingulata(C. gloeosporioides)로 동정하였다.