• The Plant Pathology Journal
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• 제24권4호
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• pp.461-468
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• 2008

An endophytic bacterial strain YC5480 producing antifungal and phytotoxic compounds simultaneously was isolated from the surface sterilized root of Artemisia sp. collected at Jinju area, Korea. The bacterial strain was identified as a species of Pseudomonas brassicacearum based on its 16S rRNA gene sequence analysis and physiological and biochemical characteristics. The seed germination and growth of monocot and dicot plants were inhibited by culture filtrate (1/10-strength Tryptic Soy Broth) of the strain. The germination rate of radish seeds in the culture filtrate differed in various culture media. Only 20% of radish seeds germinated in the culture media of 1/2 TSB for 5 days incubation. Mycelial growth of fungal pathogens, Colletotrichum gloeosporioides, Fusarium oxysporum and Phytophthora capsici was also inhibited by the culture filtrate of the strain YC5480. An antifungal compound, KS-1 with slight inhibitory activity of radish seed germination at 1,000 ppm and a seed germination inhibitory compound, KS-2 without suppression of fungal growth were produced simultaneously in TSB. The compounds KS-1 and KS-2 were identified to be 2,4-diacetylphloroglucinol (DAPG) and 2,4,6-trihydroxyacetophenone (THA), respectively.

• 식물병연구
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• 제10권1호
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• pp.63-68
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• 2004

벼에서 문제시되는 도열병과 잎집무의마름병을 생물학적으로 방제하기 위해 병원균과 생태학적 지위가 비슷한 벼 뿌리에서 내생하는 S. marcescens 23 균주를 분리하였다. 선발 균주들을 공시하여 R. solani와 P. grisea에 대한 길항능력을 검정하여 R. solani와 P. grisea에 각각 83.9％. 88.3％의 높은 억제율을 보인 RSm220 균주를 선발하였다. 선발된 RSm220은 생리ㆍ생화학적 특성 검정결과 S. marcescens type strain과 높은 상관성을 나타내었고. 16S rDNA sequencing에 의한 계통 분석에 의해 S. marcescens의 16S rDNA sequence에 98.2％ 유사성을 나타내어 S. marcescens로 동정되었다 내생성 S. marcescens RSm220은 벼 도열병과 잎집무늬마름병에 대한 생물학적 방제제로의 사용이 가능할 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제15권1호
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• pp.112-117
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• 2005

Abstract Griseofulvin has been used as an antifungal antibiotic for the treatment of mycotic diseases of humans and veterinary animals. The purpose of this work was to identify a griseofulvin-producing endophytic fungus from Abies holophylla and evaluate its in vivo antifungal activity against plant pathogenic fungi. Based on nuclear ribosomal ITS1-5.8SITS2 sequence analysis, the fungus was identified and labeled as Xylaria sp. F0010. Two antifungal substances were purified from liquid cultures of Xylaria sp. F0010, and their chemical identities were determined to be griseofulvin and dechlorogriseofulvin through mass and NMR spectral analyses. Compared to dechlorogriseofulvin, griseofulvin showed high in vivo and in vitro antifungal activity, and effectively controlled the development of rice blast (Magnaporthe grisea), rice sheath blight (Corticium sasaki), wheat leaf rust (Puccinia recondita), and barley powdery mildew (Blumeria graminis f. sp. hordei), at doses of 50 to 150 ${\mu}$g/ml, depending on the disease. This is the first report on the production of griseofulvin and dechlorogriseofulvin by Xylaria species.

• 미생물학회지
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• 제47권4호
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• pp.375-380
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• 2011

천안의 단국대학교 근처에서 채취된 벼 뿌리로부터 내생 방선균 한 주를 분리 동정하였다. 표면 살균된 벼 뿌리를 분리 배지 위에 올려 놓고 배양하면 4주 후에 뿌리 표면에 형성된 방선균 콜로니를 볼 수 있었다. 이 중에서 한 균주 JK-5를 분리하여 동정하였다. 16S rDNA 염기서열을 확인한 결과 이 분리균주 JK-5는 Streptomyces diastaticus subsp. ardesiacus와 동일한 균주였다. 형태학적 관찰과 화학분류학적 결과에 의해 분리균주 JK-5의 분류학적 위치를 확인하였다. 기중균사의 형태는 flexible하며 포자사슬은 타원형의 약 30개 정도의 매끄러운 포자로 이루어 졌다. 세포벽은 L,L-diaminopimelic acid를 포함하고 있었다. 당 분석에서는 특이적인 당이 발견되지 않았다. 지방산으로는 anteiso-15:0, anteiso-17:0, iso-16:0 가 주요 성분이었다. 퀴논 분석결과 MK-9 ($H_6$)와 MK-9 ($H_8$)이 주요 성분으로 나타났다. GC 함량은 72%로 측정되었다. 식물병원성 곰팡이에 대하여 비교적 높은 항진균활성을 보여 주었다. 벼에 감염된 분리균주 JK-5가 뿌리와 줄기에서 균사체를 형성하며 왕성하게 생장하는 것을 SEM을 통하여 확인하였다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.161-161
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• 2017

Seed endophytes are very remarkable groups of bacteria for their unique abilities of being vertically transmitted and conserved. As plants attain hybrid vigor and heterosis in the process of crossbreeding, this might also lead to the changes in the community structure and diversity of plant endophytes in the hybrid plants ultimately affecting the endophytes of the seeds. It would be interesting to characterize how seed endophyte composition change over time. The objective of this study is to gain insights into the influence of natural crossbreeding and parental lineage in the seed bacterial endophytic communities of two pure inbred lines exploring contributions of the two most important sources of plant endophytes - colonization from external sources and vertical transmission via seeds. Total genomic DNA was isolated from rice seeds and bacterial DNA was selectively amplified by PCR. The diversity of endophytic bacteria was studied through Terminal-Restriction Fragment Length Polymorphism (T-RFLP) analysis. Diversity between the original parents and the pure inbred line may show significant differences in terms of richness, evenness and diversity indices. Heat maps reveal astonishing contributions of both or either parents (IR29 ${\times}$ Pokkali and AT401 ${\times}$ IR31868) in the shaping of the bacterial seed endophytes of the hybrid, FL478 and IC32, respectively. Most of the T-RFs of the subsequent pure inbred line could be traced to any or both of the parents. Comparison of common and genotype-specific T-RFs of parents and their offspring reveals that majority of the T-RFs are shared suggesting higher transmission of bacterial communities common to both parents. The parents influence the bacterial community of their offspring. Unique T-RFs of the offspring also suggest external sources of colonization particularly as the seeds are cultivated in different ecogeographical locations. This study showed that host parental lines contributed greatly in the shaping of bacterial seed endophytes of their offspring. It also revealed transmission and potential conservation of core seed bacterial endophytes that generally become the dominant microbiota in the succeeding generations of plant hosts.

• Mycobiology
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• 제45권3호
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• pp.178-183
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• 2017

Diabetes mellitus is a chronic disorder which affects millions of population worldwide. Global estimates published in 2010 reported the world diabetic prevalence as 6.4%, affecting 285 million adults. Foot ulceration and wound infection are major forms of disabilities arising from diabetic diseases. This study was aimed to develop a natural antimicrobial finishing on medical grade textile that meets American Association of Textiles Chemists and Colorists (AATCC) standard. The textile samples were finished with the ethanolic extract of Penicillium amestolkiae elv609, an endophytic fungus isolated from Orthosiphon stamineus Benth (common name: cat's whiskers). Endophyte is defined as microorganism that reside in the living plant tissue, without causing apparent disease symptom to the host. The antimicrobial efficacy of the ethanolic extract of P. minioluteum was tested on clinical pathogens isolated from diabetic wound. The extract exhibited significant inhibitory activity against 4 bacteria and 1 yeast with the minimal inhibitory concentration ranged from 6.25 to 12.5 mg/mL. The results indicate different susceptibility levels of the test microorganism to the ethanolic extract. However, the killing activity of the extract was concentration-dependent. The finished medical textile showed excellent antimicrobial efficacy on AATCC test assays. All the microbial cultures treated with the textile sample displayed a growth reduction of 99.9% on Hoheinstein Challenge Test. The wash durability of the finished textile was found good even after 50 washes with commercial detergent. Besides, the gas chromatography mass spectrometry analysis showed that 6-octadecenoic acid and diethyl phthalate were the main bioactive constituents of the extract. In conclusion, the developed medical textile showed good antimicrobial efficacy on laboratory tests. This work can be extended to in vivo trials for developing healthcare textile products for antimicrobial applications.

• 농약과학회지
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• 제18권4호
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• pp.422-428
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• 2014

딸기 근권에서 분리한 내생균 중 고추역병균 방제 및 고추생육촉진 효과가 우수한 균주를 선발하였다. Pseudomonas fluorescen EP103으로 명명된 내생균주는 다른 내생균주와 비교하여 식물의 뿌리 길이와 생체 중이 크게 증가하였다. 고추역병에 대한 온실검정에서 EP103처리는 방제가 78.7%을 나타냈으며 항균력 실험결과 고추역병균을 직접 억제하지는 않았다. EP103이 처리된 고추에서는 PR1, PR10등의 병저항성 유전자가 발현되었으며 EP103의 PCR분석 결과 피올테오린, 파이로니트린, 하이드로젠 싸이아나이드, 오르화미드 등의 유용유전자를 함유하고 있음이 밝혀졌다. 따라서 본 균주는 고추역병의 생물 방제용으로 활용할 가치가 있는 것으로 판단된다.

• 한국균학회지
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• 제42권4호
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• pp.262-268
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• 2014

수호초로부터 분리된 DUCC5000 균주를 형태적, 분자생물학적 분류를 통해 Paraconiothyrium brasiliense로 동정하였다. 본 균은 기존에 알려진 P. brasiliense 균주의 ITS 염기서열과 100%의 상동성을 보였다. 계통유전학적 분석 결과 P. brasiliense 균주와 같은 clade를 형성하였다. 서로 다른 영양 배지와 pH 조건 하에서 균사생육 특성을 조사한 결과 oatmeal agar 배지와 pH 9에서 최적의 생장을 보였다. 배지 종류에 따라 그리고 pH 조건에 따라 균총 형태가 달라지는 특성을 지니고 있었다. Chroma 반응배지를 이용하여 7가지 세포외 효소의 분비 능력을 조사한 결과 ${\beta}$-glucosidase 활성이 가장 활발하였고 CM-cellulase와 xylerase에서는 활성이 미약하였다. 인공 접종하였으나 수호초에 대한 병원성은 나타내지 않았다. 본 균은 수호초에서는 국제적으로 처음 보고되는 균이다.