• The Plant Pathology Journal
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• v.24 no.1
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• pp.52-57
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• 2008

Twenty isolates of Bacillus spp. obtained from livestock manure composts and cotton-waste composts were tested for in vitro antagonistic effects against soilborne plant pathogenic fungi, Fusarium oxysporum, Phytophthora capsici, Rhizoctonia solani AG-4, and Sclerotinia sclerotiorum. Seven isolates of Bacillus spp. had antagonistic effects on mycelial growth of all the isolates of F. oxysporum tested. The bacterial isolate RM43 was the most effective to inhibit the mycelial growth of the fungal isolates. Twelve isolates of Bacillus spp. had antagonistic effects on mycelial growth of all the isolates of P. capsici tested. The bacterial isolates M34 and M47 were very effective to inhibit the mycelial growth of the fungal isolates. Thirteen isolates of Bacillus spp. had antagonistic effects on mycelial growth of all the isolates of R. solani AG-4 tested. The bacterial isolates M27 and M75 were very effective to inhibit the mycelial growth of the fungal isolates. Fourteen isolates of Bacillus sp. had antagonistic effects on mycelial growth of all the isolates of S. sclerotiorum tested. The bacterial isolates M49 and M75 were very effective to inhibit the mycelial growth of the fungal isolates. The antagonistic effects of most Bacillus spp. isolates against the isolates of the four fungi differed depending on the fungal species and the isolates of each fungus. The bacterial isolates M27 and M75 were the most effective to inhibit the mycelial growth of all four fungi.

• Weed & Turfgrass Science
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• v.6 no.2
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• pp.157-164
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• 2017

Functional microorganisms decompose various organic matter by enzyme activity and suppress plant disease caused by pathogen. This study was conducted to isolate and select functional microorganisms with protein or carbohydrate degradation activities and antagonistic activity against turfgrass fungal pathogens for eco-friendly turfgrass management in golf course from compost containing livestock manure of poultry or swine. Totally 68 isolates collected from livestock manure compost strains were isolated and tested for their activities of amylase, protease and lipase and antagonistic activities against Rhizoctonia solani AG2-2, R. solani AG1-1, and Sclerotinia homoeocarpa. Among the isolates, 34 strains were selected as functional microbes showing higher activities of amylase and protease. Three isolates of ASC-14, ASC-18, and ASC-35 among the 34 strains were selected as antifungal bacterial strains repressing the above 3 turfgrass fungal pathogens. Analysis results of 16s rRNA gene sequence and phylogenic cluster indicated that ASC-14 and ASC-18 belonged to Bacillus amyloliquefaciens, while ASC-35 was B. subtilis, respectively.

• Microbiology and Biotechnology Letters
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• v.36 no.4
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• pp.268-275
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• 2008

In order to develop the multi-functional rhizobacteria that can exert positive effect on the growth of plants growing in the coastal sand dune located along East Coast of Korea, rhizospheral bacteria of 11 different plants from this area were isolated 1,330 rhizobacteria. Among these, 23 strains were able to produce auxin and had spectrum of antagonism toward various phytopathogenic microbes. To know the mechanism of this antifungal activity, these 23 strains were subjected to further analyses; 19 strains of these produced siderophore as determined by color reaction on CAS-blue plate, 4 strains produced antifungal cellulase as judged by color change on CMC-Congo red plate, 17 strains were able to utilized insoluble phosphate salts, also determined by clear zone formation on PVK medium. Identification of the strain was assigned to all 23 strains by l6s rDNA sequence analysed, and all were identified to be in the genus of Bacillus and Pseudomonas. One strain of these, denoted Pseudomonas fluorescens IB4-14, showed ACC deaminase activity which is known to be involved in the resistance of environmental stress such as salt and drought. Also, P. fluorescens IB4-l4 showed the germination stimulation and roots growth promoting activity on the in vivo assay of Lysimachia mauritiana Lam. (spoonleaf yellow loosestrife).

• Korean Journal of Microbiology
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• v.42 no.2
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• pp.135-141
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• 2006

We isolated a bacterium which produces antifungal substances from the Sanktpeterburg soils at Russia. The iso-lated strain was identified as Brevibacillus sp. and shown a strong antifungal activity on plant pathogenic fungi. Brevibacillus sp. KMU-391 produced maximum level of antifungal substances under incubation aerobically at $30^{\circ}C$ for 48 hours in trypticase soybean broth containing 1.0% sucrose and 1.0% polypeptone at 180 rpm and initiated pH adjusted to 7.0. Precipitate of culture broth by $30{\sim}60%$ ammonium sulfate precipitation exhibited strong antifungal activity against Didymella bryoniae by dry cell weight. Butanol extract of cultured broth also shown fungal growth inhibitory activity against Botrytis cinerea KACC 40573, Botrytis fabae KACC 40962, Colletotrichum gloeosporioides KACC 40804, Colletotrichum orbiculare KACC 40808, Didymella bryoniae KACC 40669, Fusarium graminearum KACC 41040, Fusarium oxysporum KACC 40037, Fusarium oxysporum KACC 40052, Fusarium oxysporum f, sp. radicis-Iycopersici KACC 40537, Fusarium oxysporum KACC 40902, Monosporascus cannonballus KACC 40940, Phytophthora camvibora KACC 40160, Rhizoctonia solani AG-1(IA) KACC 40101, Rhizoctonia solani AG-4 KACC 40142, and Scleotinia scleotiorum KACC 41065 by agar diffusion method.

• Research in Plant Disease
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• v.21 no.1
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• pp.12-19
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• 2015

Antimicrobial activities of nano-materials were tested against several plant pathogens. Twelve different nano-materials were used to observe the antagonistic activity against three kinds of mold and sixteen different kinds of watermelon fruit rot pathogens (Acidovorax citrulli). According to the results, no antagonism have been found against the pathogen, Cylindrocarpon destructans. However in the case of Pythium ultimum, combination of Brass/Glucose 1,000 ppm confirmed the mycelial growth reduction by 94%. In addition, little effect was found against Rhizoctonia solani by Ag/Glucose 3,000 ppm. The remaining other nano-materials have different antimicrobial effect depending on the strains of A. citrulli. But in the case of lime (Cu/Salt 1,000 ppm) highest antimicrobial activity was observed with 97%. Moreover growth of five different strains of A. citrulli was checked by 99% with the combination of Ag/Glucose 1,000 ppm. 92% reduction of A. citrulli growth was observed with $Brass/CaCO_3$ 3,000 ppm. Tested nano-materials against different plant pathogens in this study showed the antimicrobial activity at the range of 24-70%.

• Mycobiology
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• v.40 no.1
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• pp.59-65
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• 2012

Antagonistic microorganisms against $Rhizoctonia$ $solani$ were isolated and their antifungal activities were investigated. Two hundred sixteen bacterial isolates were isolated from various soil samples and 19 isolates were found to antagonize the selected plant pathogenic fungi with varying degrees. Among them, isolate C9 was selected as an antagonistic microorganism with potential for use in further studies. Treatment with the selected isolate C9 resulted in significantly reduced incidence of stem-segment colonization by $R.$ $solani$ AG2-2(IV) in Zoysia grass and enhanced growth of grass. Through its biochemical, physiological, and 16S rDNA characteristics, the selected bacterium was identified as $Bacillus$ $subtilis$ subsp. $subtilis$. Mannitol (1%) and soytone (1%) were found to be the best carbon and nitrogen sources, respectively, for use in antibiotic production. An antibiotic compound, designated as DG4, was separated and purified from ethyl acetate extract of the culture broth of isolate C9. On the basis of spectral data, including proton nuclear magneric resonance ($^1H$ NMR), carbon nuclear magneric resonance ($^{13}C$ NMR), and mass analyses, its chemical structure was established as a stereoisomer of acetylbutanediol. Application of the ethyl acetate extract of isolate C9 to several plant pathogens resulted in dose-dependent inhibition. Treatment with the purified compound (an isomer of acetylbuanediol) resulted in significantly inhibited growth of tested pathogens. The cell free culture supernatant of isolate C9 showed a chitinase effect on chitin medium. Results from the present study demonstrated the significant potential of the purified compound from isolate C9 for use as a biocontrol agent as well as a plant growth promoter with the ability to trigger induced systemic resistance of plants.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.492-500
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• 2015

Our previous report demonstrated successful isolation of soil-borne bacteria that suppressed the potential of Rhizoctonia solani AG2-2 (IV) causing turfgrass large patch disease when applied to Korean lawngrass (Zoysia japonica). The current study aimed to uncover the mechanisms of this antagonism of Rhizoctonia solani and to define culture conditions for the isolated microbes. We found that two Bacillus isolates, I-009 and FRIN-001-1 strains, produced cellulase and siderophore, but not chitinase, while the Pseudomonas YPIN-022 strain was found to release only siderophore, implying that three antagonistic bacteria commonly interrupt Fe uptake by the large patch pathogen. The I-009 and FRIN-001-1 isolates grew best at 35 and $30^{\circ}C$ in growth medium of pH 5 to 8 for 32 and 28 h, respectively, while optimum growth for the YPIN-022 strain was found at $35^{\circ}C$ at pH 5 to 9 for 24 h. Good growth of I-009 and YPIN-022 over 24 h was obtained in M9 minimal medium supplemented with 1% sucrose, 0.5% yeast extract and 0.1% potassium chloride. FRIN-001-1 grew well in M9 medium with 1% mannitol, 0.5% yeast extract and 0.1% potassium phosphate dibasic.

• The Korean Journal of Mycology
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• v.37 no.2
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• pp.181-188
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• 2009

A Gram-positive, rod-shaped bacteria named DY5 was isolated from a peat sample collected from Daeam mountain in Korea. The culture filtrate of the bacterial isolate DY5 showed a broad spectrum of antifungal activity on various crop pathogenic fungi such as Trichoderma koningii, Fusarium oxysporum, Colletotrichum gloeosporioides, Sclerotinia sclerotiorum, Rhizoctonia solani AG-1(IA) For the identification of the DY5, morphological, biochemical, API 50 CHB test, analysis of fatty acid and molecular phylogenetic approaches were performed. The DY5 was found to be a member of the genus Paenibacillus on the basis of morphological and biochemical analysis. The 16S rRNA of DY5 showed high similarity(98%) with Paenibacillus polymyxa. On the basis of these results, the DY5 was identified as Paenibacillus polymyxa. Antifungal substance of the DY5 would be mild alkaline proteine molecule. The DY5 seems to have a great potential to be a biocontrol agent against various crop pathogens.

• Applied Biological Chemistry
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• v.34 no.1
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• pp.54-60
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• 1991

Serratia marcescens CK-3, decomposing chitin which is a mar component of cell wall in phyitopathogenic fungi, was isolated from the continuous cropping rhizosphere of pepper and cucumber and its enzymatic property was examined. S. marcescens CK-3 was found tn have an tagonistic effects against, Fusarium axysporum and Rhizoctonia solani and to have complex enzyme system such as chitinase, laminarinase, and proteinase. The preferable composition of the medium for production of chitinase was fond and was as follows : colloidal chitin 1.5%, tryptone 0.5%, glucose 1.0%, peptone 0.2%, $MgSO_4{\cdot}7H_2O\;0.1%,\;K_2HPO_4\;0.1%,\;and\;NaCl\;0.1%$(w/v), pH 6.8. The maximum enzyme production was observed after culture of 72 hours at $30^{\circ}C$ using a medium containing the above chemical composition. The optimal pH and temperature for in vitro activity of chitinase from S. marcescens CK-3 were pH 7.5 and $50^{\circ}C$, respectively. The enzyme activity in-creased by metal ions such as$Ag^+$ and $Mn^{++}$.

• Journal of Life Science
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• v.12 no.3
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• pp.242-249
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• 2002

The optimal culture conditions in 500$m\ell$ flask suture, 5$\ell$ jar fermenter and 2,000 $\ell$ large stale culture were investigated to maximize the production of antibiotic on Rhizoctonia solani AC4, the causal agent of vegetables damping-off, by the strain Bacillus ehimensis YJ-37. Starch (1.5%) as a carbon source, peptone (0.6%) as a nitrogen source and MgC1$_2$(0.15%) as a metal ion in the medium containing N $a_2$HP $O_4$(0.3%) showed the highest production of the antibiotic(s) in a rotary shake (200 rpm). Optimal initial pH of the culture medium, culture temperature and culture time for the antibiotic(s) production were pH 8.0, 32$^{\circ}C$ and 54hrs, respertively. Under the optimal renditions in flask culture, cell growth and antifungal activity (clear zone size) were 1.42 $\times$ 10$^{8}$ cfu/$m\ell$ (21g-DCW/ $\ell$) and 13.9 mm, respectively. In 5 $\ell$ jar fermenter (medium 3 $\ell$), optimal air flow, agitation speed and culture time for the antibiotic(s) production were 2 vvm, 200 rpm and 48hrs, respectively. Under the optimal conditions in 5 $\ell$ jar fermenter, tell growth and antifungal activity were 2.06 $\times$ 10$^{8}$ cfu/$m\ell$ (30g-DCW/ $\ell$) and 13.4 mm, respectively. Under the culture conditions of air flow (30 vvm) and agitation speed (200 rpm) at 32$^{\circ}C$ for 10 days in 2,000 $\ell$ large scale culture (medium 1,800 $\ell$, pH 8.0), cell growth and antifungal activity were 0.81$\times$10$^{8}$ cfu/$m\ell$ (12g-DCW/ $\ell$) and 8.6 mm, respectively.