• Journal of the Korean Wood Science and Technology
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• 제47권4호
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• pp.459-471
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• 2019

Several species of Aquilaria and Gyrinops are native to Indonesia and well known as agarwood-producing trees with a high economic value. Their bioactive compounds have a wide spectrum of uses, such as in medicine and cosmetics. These genera have undergone extensive search for novel bioactive compounds. The purpose of this study was to isolate, identify, and characterize the endophytic fungi community associated with Aquilaria malaccensis, A. microcarpa, Gyrinops versteegii, and A. crassna trees and investigate their bioactive properties as antioxidant agents and antagonists. A total of 50 fungi were successfully isolated from different tissues of the four species of agarwood-producing trees. Two isolates exhibited strong antioxidant activity, namely, Apodus oryzae (R2MC3A, $IC_{50}$ 60.92 mg/mL) and Diaporthe sp. (P1DS1[C], $IC_{50}$ 76.65 mg/mL). Two isolates, Pestalotiopsis theae (P3BS3[B]) and Curvularia sp. (P2CD3A), showed >75% antifungal activity against pathogenic Fusarium solani. The results revealed that endophytic fungi associated with the studied agarwood-producing trees had potential antioxidant and antifungal activities for further applications in biotechnology.

• 농약과학회지
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• 제17권4호
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• pp.379-387
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• 2013

지자체에서 배양하여 보급되고 있는 농업미생물 활용을 증진할 목적으로 18개 농업기술센터에서 51종의 미생물을 수집하여 작물생장촉진 및 식물병 방제와 관련한 기능성인 항균활성, 인산가용화, IAA 및 siderophore 생성능력, 질소고정능력, 가수분해활성을 비교 조사하여 최종적으로 항균활성이 우수하고 다양한 농업적 기능을 보이는 Panenibacillus polymyxa CW균주를 선발하였다. P. polymyxa CW균주는 벼 도열병균, 고추 탄저병균, 채소류 시들음병균, Phomopsis sp., 양파 검은곰팡이병균, 잘록병균(Rhizoctonia solani) 및 고추 역병균에 대하여 높은 항균활성을 보였다. 시험 병원균 중 잘록병균을 제외한 모든 병원균에 대하여 P. polymyxa CW균주는 농과원에서 보유하고 있는 P. polymyxa AC-1보다 높은 항균활성을 보였다. P. polymyxa CW균주는 항균활성 외에도 siderophore 생성, IAA 생성 및 질소고정 능력이 우수한 것으로 나타났다. P. polymyxa CW균주의 siderophore 생성능력은 P. polymyxa AC-1과 비슷하였으나 IAA 생성이나 질소고정능력은 P. polymyxa AC-1보다 우수하였다. 그러나 가수분해능력에 있어서는 P. polymyxa CW균주와 P. polymyxa AC-1균주 모두 활성을 보이지 않았다. 고추 흰가루병을 대상으로 P. polymyxa CW균주를 농도별로 처리하고($10^8$, $10^7$. $10^6$ cfu/ml) 처리 후 10일에 병 억제효과를 조사하였을 때, 가장 높은 농도처리에서 병 발생을 68.3%까지 억제하였다. P. polymyxa CW균주의 처리농도가 감소됨에 따라 병 방제효과도 비례해서 감소되었다. 또한 토마토 흰가루병에 대하여 P. polymyxa CW균주 배양액을 $10^6$, $10^7$, $10^8$ 농도로 희석하여 처리하고 7일 후에 병 발생정도를 조사한 결과, 무처리의 병반면적율이 56.3%인데 비하여 0.03, 19.5, 45.7%로 병 발생을 현저히 억제하는 것으로 나타났다. 고추 흰가루병의 경우처럼 토마토 흰가루병에 대한 P. polymyxa CW균주의 방제효과도 처리농도에 비례하는 것으로 나타났다. P. polymyxa CW균주는 고추 및 토마토 흰가루병에 대하여 높은 방제효과를 보였으며, 방제효과가 밀도에 좌우되는 것으로 나타나 시험한 두가지 흰가루병 방제에 대한 작용기작은 항생작용으로 추측되며 효과적인 병 방제를 위해서는 $10^8$ cfu/ml 이상 농도로 처리해야 할 것으로 생각되었다. 이상의 결과를 근거로 P. polymyxa CW균주는 고추 및 토마토 흰가루병 방제를 위한 유망한 방제제로 사용될 수 있을 것으로 사료된다.

• The Plant Pathology Journal
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• 제15권3호
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• pp.152-157
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• 1999

An antibiotic compound was isolated from the culture of an antagonist against Fusarium oxysporum f. sp. sesami, Bacillus polymyxa strain KB-8, and tested for the control of Fusarium wilt of sesame in greenhouse conditions. Optimum conditions for culturing the antagonist to obtain the maximum antibiotic activity were determined using different culture media, initial medium acidity, and incubation periods for which yeast -malt extract agar with the initial acidity of pH 5 and over 13 days culture were best. Antibiotic substances extracted by methanol had 2 main fractions, KB-8A and KB-8B, in thin layer chromatography (OLC) with Rf values of 0.35 and 0.67 in a solvent system of chloroform : methanol = 7 : 3. The fraction KB-8A wa purified further by XAD-2, silica gel and Sephadex LH-20 column chromatography, and crystalization. Its minimum inhibitory concentrations (MICs) were $12.8\mu\textrm{g}$/ml for F. oxysporum and Alternaria mali, $6.4\mu\textrm{g}$/ml for Colletotrichum gloeosporioides and Rhizoctonia solani, and $3.2\mu\textrm{g}$/ml for Phytophthora capsici. Soil drenching of antibiotic KB-8A in the concentrations of $13.0\mu\textrm{g}$/ml and $26.0\mu\textrm{g}$/ml effectively inhibited the Fusarium wilt of sesame in a greenhouse test, which appeared to be comparable to the fungicide benlate of $6.5\mu\textrm{g}$ a. i./ml.

• Journal of Microbiology and Biotechnology
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• 제23권1호
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• pp.29-35
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• 2013

A Nodulisporium sp. (Hypoxylon sp.) has been isolated as an endophyte of Thelypteris angustifolia (Broadleaf Leaf Maiden Fern) in a rainforest region of Central America. It has been identified both on the basis of its morphological characteristics and by scanning electron microscopy as well as ITS sequence analysis. The endophyte produces volatile organic compounds (VOCs) that have both fuel (mycodiesel) and use for biological control of plant disease. When grown on potato dextrose agar, the organism uniquely produces a series of ketones, including acetone; 2-pentanone; 3-hexanone, 4-methyl; 3-hexanone, 2,4-dimethyl; 2-hexanone, 4-methyl, and 5-hepten, 2-one and these account for about 25% of the total VOCs. The most abundant identified VOC was 1,8 cineole, which is commonly detected in this group of organisms. Other prominent VOCs produced by this endophyte include 1-butanol, 2-methyl, and phenylethanol alcohol. Moreover, of interest was the presence of cyclohexane, propyl, which is a common ingredient of diesel fuel. Furthermore, the VOCs of this isolate of Nodulisporium sp. were selectively active against a number of plant pathogens, and upon a 24 h exposure caused death to Phytophthora palmivora, Rhizoctonia solani, and Sclerotinia sclerotiorum and 100% inhibition to Phytophthora cinnamomi with only slight to no inhibition of the other pathogens that were tested. From this work, it is becoming increasingly apparent that each isolate of this endophytic Nodulisporium spp., including the Daldina sp. and Hypoxylon spp. teleomorphs, seems to produce its own unique set of VOCs.

• Journal of Microbiology and Biotechnology
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• 제15권4호
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• pp.895-898
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• 2005

In the course of searching for potent chitin synthase 1 inhibitors from natural resources, Streptomyces sp. A6705 was found to exhibit potent inhibitory activity against the chitin synthase 1 from C. albicans (CaCHS1p). As a result, the inhibitor was isolated and identified using a series of chromatographies. Through chemical analyses with UV spectrophotometry, MS spectrometry, and various NMR techniques, the inhibitor was identified as N,N-bis(2-phenylethyl)urea. The compound exhibited strong inhibitory activity against the chitin synthase 1 from C. albicans with an $IC_{50}$ of 14 ${\mu}g$/ml, representing a similar inhibitory activity to that of the well-known chitin synthase inhibitor, polyoxin D ($IC_{50}$ 15 ${\mu}g$/ml). However, the compound showed no inhibitory activity against the chitin synthase 2 of Saccharomyces cerevisiae up to 280 ${\mu}g$/ml, which is structurally and functionally analogous to CaCHS 1 p. In addition, the compound exhibited weak antifungal activities against Cryptococcus neoformans and Rhizoctonis solani.

• Journal of Microbiology and Biotechnology
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• 제16권3호
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• pp.450-456
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• 2006

Pseudomonas fluorescens MC07 is a growth-promoting rhizobacterium that suppresses mycelial growth in fungi such as Rhizoctonia solani, Pythium ultimum, Fusarium oxysporum, and Phytophthora capsici. To determine the role of the bacterium's antifungal activity in disease suppression, we screened 2,500 colonies generated by Tn5lacZ insertions, and isolated a mutant 157 that had lost antifungal activity. The EcoRI fragment carrying Tn5lacZ was cloned into pBluescript II SK(+) and used as a probe to isolate wild-type clones from a genomic library of the parent strain, MC07. Two overlapping cosmid clones, pEH4 and pEH5, that had hybridized with the mutant clone were isolated. pEH4 conferred antifungal activity to the heterologous host P.fluorescens strain 1855.344, whereas pEH5 did not. Through transposon mutagenesis of pEH4 and complementation analyses, we delineated the 14.7-kb DNA region that is responsible for the biosynthesis of an antifungal compound. DNA sequence analysis of the region identified 11 possible open reading frames (ORF), ORF1 through ORF11. A BLAST search of each putative protein implied that the proteins may be involved in an antifungal activity similar to polyketides.

• Journal of Microbiology and Biotechnology
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• 제15권5호
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• pp.984-991
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• 2005

Soil or seed applications of plant growth-promoting rhizobacteria (PGPR) have been used to enhance growth of several crops as well as to suppress the growth of plant pathogens. In this study, we selected a PGPR strain, Paenibacillus polymyxa strain E681, out of 3,197 heat-stable bacterial isolates from winter wheat and barley roots. Strain E681 inhibited growth of a broad spectrum plant pathogenic fungi in vitro, and treatment of cucumber seed with E681 reduced incidence of damping-off disease caused by Pythium ultimum, Rhizoctonia solani, or Fusarium oxysporum. When inoculated onto seeds as vegetative cells or as endospores, E681 colonized whole cucumber root systems and root tips. Different temperatures such as $20^{\circ}C\;and\;30^{\circ}C$ did not affect root colonization by strain E681. This colonization was associated with a consistent increase in foliar growth of cucumber in the greenhouse. These results indicate that strain E681 is a promising PGPR strain for application to agricultural systems, particularly during the winter season.

• 미생물학회지
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• 제8권2호
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• pp.53-64
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• 1970

In order to study ecology of microorganisms during Takju brewing, microflora changes were examined fromm the start to the sixth day of Takju fermentation in 24 hours intervals. Takju made from rice, flour and dried sweet potato in a liter volume open container at the laboratory and a sanple of Takju brewing factory were studied for their microflora and their changes during fermentationl together with a sample of Kokja. Results obtained were as follows ; 1. The followings were the identified microorganisms in Kokja. The molds ; Absidia spinosa, Aspergillus parasiticus. The yeasts ; Candida melinii, Candida Solani, Hansenula anomala. The bacteria ; Luctobacillus casei, Leuconostoc mesenteroides, Bacillus subtilis, Bacillus pumilus. 2. Torulopsis inconspicua, Lactobacillus casei, Leuconotoc mesenteroides, Bacillus subtilis, Bacillus pumilus were isolated from main mash of laboratory-made Takju samples. The yeast, Torupsis inconspicua which was not present in Kokja and, probably of a contaminant yeast, dominated the yeast flora of Takju mash of rice, flour and sweet potato of labotatory brewing. The laboratory brewing lost also always showed large population of lactic acid bacteria flora. 3. None of the wild yeasts which were present in Kokja appeared in Takju mashes. The Kokja appears to be of no use as the yeast source for Takju fermentation. Also the Kokja appears to be of not so effective amylolytic and proteolytic enzyme sources considering the microflora characteristics. Probably the major role of Kokja in Takju fermentation may be to contribute in taste formation. 4. Inoculation of Sacharomyces cerevisiae into the mash to the level of $10^7$ ml at the start of fermentation greatly changed the ecological aspects eliminating conditions of rather slow rising of natural contaminant yeast populaiton and fermentation which might give rise to prosperity of lactic acid and Bacillus bacteria that would be avoidable. 5. Examination of microflora of the large factory scale Takju fermentation showed the quite similar pattern of microflora and their changes to that of the cultured yeast-inoculated laboratory batch Takju fermentation. The cultured yeast dominated as the only predominant microflora, and the lactic acid bacteria flora were completely suppressed and aerobic bacteria, greatly. Probably this may be the regular microflora pattern of normal Takju fermentation. The role of lactic acid bacteria and aerobic bacteria in Takju fermentation may not be clear yet from this experiment alone.

• 한국유기농업학회지
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• 제29권2호
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• pp.257-273
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• 2021

취나물 재배 시 문제가 되는 점무늬병(Septoria sp.)에 대해 항균활성을 나타내는 세균 P. polymyxa JE201를 분리하였다. JE201 균주를 이용하여 점무늬병 방제효과 포장검정을 시행한 결과, 대조구로 사용한 세레나데 맥스와 비슷한 정도의 방제효과를 나타낼 정도로 효과가 있었으며, 다른 식물 병원성 진균에 대한 항균활성 스펙트럼을 조사한 결과, 10종 중 9종에 대해서도 균사생장억제력이 크게 나타나는 것으로 보아, 앞으로 추가적인 연구를 통해 다른 병에도 적용할 수 있을 것으로 기대된다.

• Journal of Microbiology and Biotechnology
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• 제33권5호
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• pp.607-620
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• 2023

The biocontrol approach using beneficial microorganisms to control crop diseases is becoming an essential alternative to chemical fungicides. Therefore, new and efficient biocontrol agents (BCA) are needed. In this study, a rhizospheric actinomycete isolate showed unique and promising antagonistic activity against three of the most common phytopathogenic fungi, Fusarium oxysporum MH105, Rhizoctonia solani To18, and Alternaria brassicicola CBS107. Identification of the antagonistic strain, which was performed according to spore morphology and cell wall chemotype, suggested that it belongs to the Nocardiopsaceae. Furthermore, cultural, physiological, and biochemical characteristics, together with phylogenetic analysis of the 16S rRNA gene (OP869859.1), indicated the identity of this strain to Nocardiopsis alba. The cell-free filtrate (CFF) of the strain was evaluated for its antifungal potency, and the resultant inhibition zone diameters ranged from 17.0 ± 0.92 to 19.5 ± 0.28 mm for the tested fungal species. Additionally, the CFF was evaluated in vitro to control Fusarium wilt disease in Vicia faba using the spraying method under greenhouse conditions, and the results showed marked differences in virulence between the control and treatment plants, indicating the biocontrol efficacy of this actinomycete. A promising plant-growth promoting (PGP) ability in seed germination and seedling growth of V. faba was also recorded in vitro for the CFF, which displayed PGP traits of phosphate solubilization (48 mg/100 ml) as well as production of indole acetic acid (34 ㎍/ml) and ammonia (20 ㎍/ml). This study provided scientific validation that the new rhizobacterium Nocardiopsis alba strain BH35 could be further utilized in bioformulation and possesses biocontrol and plant growth-promoting capabilities.