• Korean Journal Plant Pathology
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• v.11 no.1
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• pp.39-46
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• 1995

Ditylenchus destructor isolated from diseased ginseng roots was cultured on ginseng calli, fungal mycelium (Fusarium solani), carrot discs and radish sprouts. Effects of temperature, organic material and flooding on the nematode population changes were examined. D. destructor multiplied readily on the culture media except radish sprout medium, and was cultured best on the fungal culture at 2$0^{\circ}C$. Feeding of the fungal hypha and radish root hairs, molting and mating in the fungal culture medium were observed. Addition of organic materials (perilla, sesame, soybean and ginseng leaves) in soil significantly increased Aphelenchus avenae and saprophytic nematode populations, while D. destructor populations changed little and the nematode population growths were limited by the organic amendments (except sesame leaves). The nematode populations in soil including D. destructor were decreased by flooding. The results indicate that D. destructor may survive but not multiply readily in soil without host plants and that it can be effectively controlled by flooding.

• The Plant Pathology Journal
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• v.29 no.4
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• pp.435-439
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• 2013

Rice blast fungus, Magnaporthe oryzae, inflicts serious damage to global rice production. Due to high variability of this fungal pathogen, resistance of newly-released rice cultivars is easily broken down. To understand the population structure of M. oryzae, we analyzed the genetic diversity of the Korean population using multilocus microsatellite typing. Eleven microsatellite markers were applied to the population of 190 rice isolates which had been collected in Korea for two decades since the 1980's. Average values of gene diversity and allele frequency were 0.412 and 6.5, respectively. Comparative analysis of the digitized allele information revealed that the Korean population exhibited a similar level of allele diversity to the integrated diversity of the world populations, suggesting a particularly high diversity of the Korean population. Therefore, these microsatellite markers and the comprehensive collection of field isolates will be useful genetic resources to identify the genetic diversity of M. oryzae population.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.7
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• pp.918-921
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• 2000

A comparative study on rumen bacterial and protozoal population and fungal zoospores in cattle (Brahman$\times$Native) and swamp buffalo (Bubalus bubalis) was conducted. Forty animals, twenty of each, with same sex and similar age which were raised under similar condition in the Northeast of Thailand, were used. Rumen digesta were sampled immediately post slaughtering for total microscopic counts of bacteria, protozoa and fungal zoospores. It was found that total bacterial population were higher in swamp buffalo that those in cattle (1.6 vs $1.36{\times}10^{8}cells/ml$) having more population of cocci, rods and ovals. Lower rumen protozoal pupulation in swamp buffalo with lower numbers of Holotrichs and Entodiniomorphs were found as compared to those in cattle. Significant higher fungal zoospore counts were in swamp buffalo than those in cattle being 7.30 and $3.78{\times}10^6$, respectively. Study under electron microscope, revealed Anaeromyces sp. with acuminate apex were more predominant in the rumen of swamp buffalo. With these findings, cattle and swamp buffaloes showing differences in rumen bacterial, protozoal population and fungal zoospore counts, offer new additional information as why swamp buffaloes exhibit conditionally better than cattle especially during long dry season without green grass.

• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.831-838
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• 2018

Trophic interactions of introduced biocontrol fungi with soil animals can be a key determinant in the fungal proliferation and activity. This study investigated the trophic interaction of an introduced biocontrol fungus with soil nematodes. The biocontrol fungus Trichoderma harzianum ThzID1-M3 and the fungivorous nematode Aphelenchoides sp. (10 per gram of soil) were added to nonsterile soil, and microbial populations were monitored for 40 days. Similar results were obtained when the experiment was duplicated. ThzID1-M3 stimulated the population growth of indigenous nematodes (p < 0.05), regardless of whether Aphelenchoides sp. was added. Without ThzID1-M3, indigenous nematodes did not increase in number and the added Aphelenchoides sp. nematodes almost disappeared by day 10. With ThzID1-M3, population growth of nematodes was rapid between 5 and 10 days after treatment. ThzID1-M3 biomass peaked on day 5, dropped at day 10, and then almost disappeared at day 20, which was not influenced by the addition of nematodes. In contrast, a large quantity of ThzID1-M3 hyphae were present in a heat-treated soil in which nematodes were eliminated. Total fungal biomass in all treatments peaked on day 5 and subsequently decreased. Addition of nematodes increased the total fungal biomass (p < 0.05), but ThzID1-M3 addition did not affect the fungal biomass. Hyphae of total fungi when homogenously distributed did not support the nematode population growth; however, hyphae of the introduced fungus did when densely localized. The results suggest that soil fungivorous nematodes are an important constraint on the hyphal proliferation of fungal agents introduced into natural soils.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.48-48
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• 2014

Arbuscular Mycorrhizal Fungi(AMF) is widespread symbiont forming mutualistic relationship with plant root in terrestrial forest in ecosystem. They provide improved absorption of nutrient and water, and enhance the resistance against plant pathogen or polluted soil, therefore AM fungi are important for survival and maintaining of individual or community of plant. For last decade, many studies about the functional variation of AM fungi on host plant growth response were showed that different geographic isolates, even same species, have different effect on host plant. However, little was known about functional variation of AM fungal isolates originated single population, which provide important insight about intraspecific diversity of AMF and their role in forest ecosystem. In this study, four AM fungal isolates of Rhizophagus clarus were cultured in vitro using transformed carrot (Daucus carota) root and they showed the difference between isolates in ontogenic characteristics such as spore density and hyphal length. The plant growth response by mycorrhizas were measured also. After 20 weeks from inoculation of these isolates to host plants, dry weight, Root:Shoot ratio, colonization rates and N, P concentration of host plant showed host plant was affected differently by AM fungal isolates. This results suggest that AM fungi have high diversity in their functionality in intraspecific level, even in same population.

• Korean Journal of Environmental Agriculture
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• v.16 no.4
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• pp.291-294
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• 1997

The purpose of this study was to investigate the change of microbial flora of using coal fly ash as humidity conditioner during the household garbage composting.The summarized results of microbial flora were as follows:There was no difference of t he seasonal fluctuation of mesophilic and themophilic microorganisms.The population of thermophilic actinomycetes was rapidly increased in winter,but not much changed in spring and summer.Thermophilic and mesophilic fungal flora were increased at the same time,but the population of thermophilic fungal flora was smaller than that of mesophilic. The population of bacteria, actinomycestes and fungi showed not much difference.

• Journal of Forest and Environmental Science
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• v.30 no.2
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• pp.179-188
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• 2014

This research reports the effects of shifting cultivation on soil environment collecting samples from 0-5 cm soil depth from five locations viz. at Burburichhara, Maichchari, Longadu, Sukurchhari and Muralipara in Rangamati district of Chittagong Hill Tracts (CHTs). Soil analyses showed that fungal and bacterial population, microbial respiration and active microbial biomass, maximum water holding capacity, conductivity and moisture contents were significantly (at least $p{\leq}0.05$) lower in shifting cultivated soil compared to adjacent mixed tree plantations at all the sites. On an average in soils of 5 different shifting cultivated lands fungal population was $1.33{\times}10^5$ CFU/g dry soil and bacterial population $1.80{\times}10^7$ CFU/g dry soil and in mixed plantations fungal population was $1.70{\times}10^5$ and bacterial population $2.51{\times}10^7$ CFU/g dry soil. Organic matter and exchangeable Ca and Mg contents were significantly (at least $p{\leq}0.05$) lower and bulk density significantly (at least $p{\leq}0.05$) higher in shifting cultivated land in most of the locations compared to adjacent mixed tree plantations. Ratios of microbial respiration and organic carbon as well as active microbial biomass and organic carbon were distinctly lower and pH higher at 3 locations in shifting cultivated soils compared to mixed plantations. Findings of various soil properties, therefore, suggest that shifting cultivation has deteriorating effects on soil environment.

• Research in Plant Disease
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• v.7 no.1
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• pp.25-30
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• 2001

Influence of soil flooding with organic matters amendment at various temperatures on population changes of fungi, including Fusarium, and bacteria in ginseng-replanting field soils was examined to evaluate the effective flooding conditions for reducing the progress of ginseng root rot. Populations of Fusarium spp. and total fungi in flooded soils declined with days after flooding. The higher was the temperature in range of 20$\^{C}$ to 35$\^{C}$, the greater was the effect of flooding on the decrease of the fungal population. Flooding of soils with organic matters amendment had synergistic effect on the decrease of the fungal population at the same temperature; Fungal populations in flooded soils with and without organic matters amendment were reduced to 1/100 and 1/10, respectively, relative to those in non-flooded soils after 60 days of treatment at 30$\^{C}$. rice straw seemed to be more effective than greens. Population changes of total bacteria in flooded soils were similar to the trend of total fungi. However, the flooding seemed to influence less effect on the bacterial population than on the fungal population. Based on these experiments, we suggest than the progress of ginseng root rot in ginseng-replanting field soils may be significantly reduced by flooding them for longer than 3 months near at 30$\^{C}$ after amendment of organic matters.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.6
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• pp.599-602
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• 1997

Fluctuation of fungal zoospores on agar strips were observed in the rumen of sheep fed three different levels of dietary concentrate, timothy hay: concentrate = 3:0 (AF diet), timothy hay: concentrate = 2:1 (MC diet), timothy hay : concentrate = 1:2 (HC diet) respectively. The number of zoospores on the strip was drastically decreased after morning feed with AF diet. The number was the highest at 0 h ($1.34{\times}10^2/cm^2$), then declined to $2.0{\times}10^3/cm^2$ at 9 h after feeding. In the rumen of animals fed MC diet, the number of zoospores decreased with time after feeding, although the decrement was slower than that with AF diet. During 0-3 h after feeding, number of zoospores was $1.6{\times}10^4/cm^2$. Although the number slightly decreased at 6 and 9 h, relatively high levels were maintained. It seems that the inducers for zoospore-release were maintained at relatively high concentration throughout incubation period. The fluctuation pattern of number of germinated zoospores was different in the rumen of animals fed HC diet from those of AF and MC diets. The number of zoospores was constantly maintained at lower level ($1.0{\times}10^3/cm^2$) than the other diets. For MC diet, continuous high number of germinated zoospores may be due to the continuous release of zoospores by hemes in timothy hay and concentrate feed, and by unknown mechanisms. Unlike AF diet which promoted relatively rapid decline of zoosporogenesis, supplementation of concentrate feed to the timothy hay did not promote such rapid decline of zoosporogenesis. It was suggested that release of inducers for zoosporogenesis from concentrate feed persisted longer time than from timothy hay. HC diet promoted the lowest zoospore production, suggested the lowest fungal population size in this experiment. These results show that an appropriate amount of concentrate may support fungal growth and stimulate zoosporogenesis in the rumen.

• The Journal of the Korean Society for Microbiology
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• v.7 no.1
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• pp.51-54
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• 1972

The determination of fungal flora in various kinds of local grains have been carded out in order to obtain an appropriate information of the population of toxigenic fungi in Korean local grains. Results of fungal examination on nine kinds of grain such as soy bean(18 samples), red bean(12 samples), rice(8 samples), kidney bean(8 samples), millet(7 samples), barley(5 samples), malze(5 samples), wheat(4 samples) and sesame(3 samples) were described in this report. 1. Of the 70 various grains, 283 colonies of fungi were isolated. Among the 283 colonies, 262 were possible to identity into 15 genera. 2. Predominant genera of fungi in most local grains were Penicillium sp.(24.39%), Aspergillus sp.(20.49%) and Alternaria sp.(13.43%).