• Mycobiology
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• v.50 no.5
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• pp.269-293
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• 2022

Oomycete pathogens that belong to the genus Phytophthora cause devastating diseases in solanaceous crops such as pepper, potato, and tobacco, resulting in crop production losses worldwide. Although the application of fungicides efficiently controls these diseases, it has been shown to trigger negative side effects such as environmental pollution, phytotoxicity, and fungicide resistance in plant pathogens. Therefore, biological control of Phytophthora-induced diseases was proposed as an environmentally sound alternative to conventional chemical control. In this review, progress on biological control of the soilborne oomycete plant pathogens, Phytophthora capsici, Phytophthora infestans, and Phytophthora nicotianae, infecting pepper, potato, and tobacco is described. Bacterial (e.g., Acinetobacter, Bacillus, Chryseobacterium, Paenibacillus, Pseudomonas, and Streptomyces) and fungal (e.g., Trichoderma and arbuscular mycorrhizal fungi) agents, and yeasts (e.g., Aureobasidium, Curvibasidium, and Metschnikowia) have been reported as successful biocontrol agents of Phytophthora pathogens. These microorganisms antagonize Phytophthora spp. via antimicrobial compounds with inhibitory activities against mycelial growth, sporulation, and zoospore germination. They also trigger plant immunity-inducing systemic resistance via several pathways, resulting in enhanced defense responses in their hosts. Along with plant protection, some of the microorganisms promote plant growth, thereby enhancing their beneficial relations with host plants. Although the beneficial effects of the biocontrol microorganisms are acceptable, single applications of antagonistic microorganisms tend to lack consistent efficacy compared with chemical analogues. Therefore, strategies to improve the biocontrol performance of these prominent antagonists are also discussed in this review.

• Journal of Korean Society of Forest Science
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• v.99 no.3
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• pp.277-284
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• 2010

rust fungus, Uromyces truncicola, infected stems, branches and leaves of Sophora japonica trees, and 78% of planted host depending on investigated sites. Teliospores of this fungus were reddish brown, global to oval and $29-37{\times}24-27\;{\mu}m$. The urediniospores were yellowish brown, elliptical to oval with spiny surface and $28-39{\times}19-22\;{\mu}m$. In the infected branches cork layers were thickened, ray parenchymatous cells were distorted, branched or combined and increased in numbers. While ray parenchymatous cells in healthy branches were one or two layers, the cells in the infected branches were three or more layers to shape fusiform. In the infected branches xylem tissues also distorted and yellowish pigments formed in the intercellular space. In the less infected trees the hairs on the branches were dense and long, and the thickness of upper epidermal cell walls were ca 23.3 ${\mu}m$, while in the highly infected trees the hairs were less dense and short, and the thickness of upper epidermal cell walls was ca 17.4 ${\mu}m$. We think individual host trees resistant to this fungus are present.

• Research in Plant Disease
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• v.13 no.3
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• pp.183-190
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• 2007

308 isolates of Ampelomyces quisqualis were isolated from powdery mildew fungi of 73 plant species in Korea from 1994 to 2004. Among them, the new mycohosts and new plant hosts of A. quisqualis were found in 13 species of powdery mildew fungi in 38 species of plant. The new hosts of A. quisqualis were Erysiphe heraclei on Heracleum moellenderfii; E. hommae on Elsholtzia splendins; E. glycines on Glycine max; E. lespedezae on Lespedeza biclor; E. pileae on Pilea mongolica; E. pisi on Phaseolus radiatus; E. polygoni on Rumex aquatica and Rumex crispus; Golovinomyce artemisiae on Artemisia princeps var. orientalis; G. cichoracearum on Rudbeckia laciniata var. hortensis; G. rubiae on Rubia akane; Oidium sp. on Valeriana fauriei, Lactuca indica var. laciniata, Carpesium triste var. manshuricum, Aster ageratoides var. turczaninow, Lufa cylindrica, Ixeris demtats Nakai, Phlox paniculata, Bidens bipinnata and Pathenocissus tricuspidata; Microsphaera alphitoides on Quercus aliema, M. pseudolonicerae on Cocculus trilobos; Podosphaera sp. on Ligustrum obtusifolium; Sphaerotheca aphanisi on Fragaria ananassa; S. balsaminae on Impatiens textori; S. fusca on Cucurbita pepo, Cucurbita maxima, Ligularia fischeri, Solanum melongena, Lagenaria leucantha, Cucumis melo var. makuwa, Acalypha australis, Cosmos bipinnatus and Aster scaber; Uncinuliella simulans on Rosa muliflora and Uncinula australiana on Lagerstroemia indica.

• Research in Plant Disease
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• v.15 no.1
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• pp.23-29
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• 2009

Cooking oil and yolk mixture (COY), a environmentally acceptable plant protection agent, and COY+$CaCO_3$+neem oil mixture were studied to control the powdery mildew occurring on eggplant, paprika, cherry tomato and maturity tomato in glass houses and vinyl houses during 2005 to 2007. The morphological changes of the pathogenic fungi on the leaf surface before and after treatment of COY were observed. COY made of rape seed oil and COY+$CaCO_3$+neem oil mixture were sprayed three times with 5 days interval to foliar parts of eggplant, paprika and tomato and the disease development were examined 5 days after final spray. In eggplant, the control efficacy of COY to powdery mildew was 94.6%. In paprika, the control efficacy of COY to powdery mildew was 91.6% and that of COY+$CaCO_3$+neem oil mixture was 96.2% that revealed little higher than COY itself. In tomatoes(cherry or maturity tomato), the control efficacy of COY were about 91 %, however, when COY mixture were sprayed to tomato leaves and stems the powdery mildew was controlled completely. Typical and healthy mycelia, conidiophores and condia were observed through scanning electron microscope in COY unsprayed leaf surface, on the other hand destroyed and winkled mycelia and conidiophores were observed in COY treated leaves regardless host plants nor taxonomic differences of fungi.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.5
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• pp.290-303
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• 2003

Modern agriculture has been heavily dependent on chemical fertilizers to meet the food demands of ever increasing population. Progressive depletion of major plant nutrients in soil due to intensive cultivation practices has also necessitated the use of higher dose of chemical fertilizers particularly in soils where the organic matter content is very low. Indiscriminate use of chemical fertilizers and pressure on agriculturists to enhance per area crop yields has led to fast depletion of fossil fuel resources with concomitant increase in the prices of chemical fertilizers and also led to environmental pollution. Hence, the current trend throughout the world is to explore the possibility of using alternate nutrient sources or increasing the efficiency of chemical fertilizers by supplementing them with organic fertilizers and bioinoculants comprising largely microbes like, bacteria, fungi, algae etc to enhance nitrogen and phosphates in the soil thus creating a sustainable agricultural environment. Among the different microbial inoculants or biofertilizers, Azospirillum could be a potential candidate due to its non specific host root colonization. It had the capability to fix $N_2$ in wide pH regimes and even in presence of combined nitrogen. Azospirillum inoculation can increase the crop yield to 10-25% and substitute 25% of recommended doses of nitrogenous fertilizers. Apart from nitrogen fixation, Azospirillum is also involved in the root improvement, the activity which was attributed to an increase in the rate of water and mineral uptake by roots. The ability of Azospirillum to produce phytohormones was reported to enhance the root respiration rate, metabolism and root proliferation. They have also been reported to produce polyhydroxybutyrate, that can be used as a biodegradable thermosplastic. A lot of studies have addressed improvements in enhancing its efficiency to fix nitrogen fixation and hormone production.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.15-15
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• 2015

Aspergillus fumigatus is a major cause of invasive aspergillosis (IA), a significant health issue worldwide with high mortality rates up to 95%. Our lab is interested in how A. fumigatus adapts to low oxygen conditions 'hypoxia', which is one of the important host microenvironments. A. fumigatus SrbA is a basic helix-loop-helix (bHLH) transcriptional regulator and belongs to sterol regulatory element binding protein (SREBP) family members. Loss of SrbA completely blocks growth in hypoxia and results in avirulence in murine models of IA suggesting an essential role of SrbA in hypoxia adaptation and virulence in A. fumigatus. We conducted chromatin immunoprecipitation sequencing (ChIP-seq) with A. fumigatus wild type using a SrbA specific antibody, and 97 genes were revealed as SrbA direct targets. One of the 'SrbA regulons' (AFUB_099590) was a putative bHLH transcriptional regulator whose sequence contained a characteristic tyrosine substitution in the basic portion of the bHLH domain of SREBPs. Therefore, we designated AFUB_099590 SrbB. Further characterization of SrbB demonstrated that SrbB is important for radial growth, biomass production, and biosynthesis of heme intermediates in hypoxia and virulence in A. fumigatus. A series of quantitative real time PCR showed that transcription of several SrbA regulons is coordinately regulated by two SREBPs, SrbA and SrbB in hypoxia. This suggests that SrbA and SrbB have both dependent and independent functions in regulation of genes responsible for hypoxia adaptation in A. fumigatus. Together, our data provide new insights into complicated roles of SREBPs in adaptation of host environments and virulence in pathogenic fungi.

• Economic and Environmental Geology
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• v.39 no.6 s.181
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• pp.629-641
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• 2006

The Standing Buddha Statue in the Gwanchoksa temple consists of medium to coarse grained biotite granodiorite with dark grey color, and it has a week gneissosity along the pegmatite veins. The results of magnetic susceptibility and geochemical patterns of the host rock of Standing Buddha Statue and the basement rock suggest that both values are formed from the co-genetic magma with the same differentiation process. The CIAs of the basement rock and the Standing Buddha Statue are calculated to 51.43 and 50.86, and the WPIs are estimated 4.52 and 8.95, respectively. So the weathering potential from the host rock of Standing Buddha Statue and basement rock prove to be high. The Standing Buddha Statue is terribly damaged with physical weathering from deterioration and exfoliation, and are scattered with secondary pollutant and precipitate. Basement rock is also in danger of ground collapse because of irregularly developed discontinuity system. Most surface of Standing Buddha Statue is seriously discolored into yellowish brown and dark gray, or black precipitates are also formed. Moreover, it is heavily covered with crustose lichen, fungi and algae, or moss are also found. In order to control the influential factors with the complex deterioration of Standing Buddha Statue, it is needed to rearrange a site environments, and conservation scientific management is required to protect it from covering lichens, exfoliations and fractures.

• Journal of Life Science
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• v.28 no.10
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• pp.1244-1253
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• 2018

Rumen microbiome consists of a wide variety of microorganisms, such as bacteria, archaea, protozoa, fungi, and viruses, that are in a symbiotic relationship in a strict anaerobic environment in the rumen. These rumen microbiome, a vital maker, play a significant role in feed fermentation within the rumen and produce different volatile fatty acids (VFAs). VFAs are essential for energy metabolism and protein synthesis of the host animal, even though emission of methane gas after feed fermentation is considered a negative indicator of loss of dietary energy of the host animal. To improve rumen microbial efficiency, a variety of approaches, such as feed formulation, the addition of natural feed additives, dietary feed-microbes, etc., have taken to increase ruminant performance. Recently with the application of high-throughput sequencing or next-generation sequencing technologies, especially for metagenomics and metatranscriptomics of rumen microbiomes, our understanding of rumen microbial diversity and function has significantly increased. The metaproteome and metabolome provide deeper insights into the complicated microbial network of the rumen ecosystem and its response to different ruminant diets to improve efficiency in animal production. This review summarized some recent advances of rumen microbiome techniques, especially "meta-omics," viz. metagenomic, metatranscriptomic, metaproteomic, and metabolomic techniques to increase feed fermentation and utilization in ruminants.

• Korean journal of applied entomology
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• v.23 no.2 s.59
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• pp.82-88
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• 1984

Fruit rot and blister canker, a disease of apple occurring severely in Korea has been studied for correct identification of the syndrome In fruit and apple trees. Among the fungi isolated from blister cankers, rough barks or fruits showing rotting of 7 different host species were Botryosphaeria berengeriana (pycnidial stage. Dethiorella mali), Penicillium expansum and Alternaria sp. from apple rots and Phomopsis sp. from pear fruit rots. The most dominant isolates were B. berengeriana. Ten isolates of D. mali were grouped in to two conidial types based up mycelial growth rate, growth habits and mycelial coloration on PDA. None of 10 isolates was chromogenic. Pycnidia in apple stems, stromatic, dark brown, globose or subglobose and the measuring were $103.5-287.5{\mu}\times92.0-287.5\mu$. The pycnidia contained hyaline, nonseptate, fusiform conidia. The sizes of pycnidiospore of isolates obtained from apple twig were $4.3-7.2{\mu}\times20.0-31.5{\mu}(average\;5.9\times25.4\mu)$. Some conidia of this fungus from apple, pear, peach and ornamental cherry showed 1-,2-,3-septate before or during germination. Microconidia were observed in pycnidia on PDA and fruit lesion of inoculated host. Symptoms on leaves and fruits were contoured brown spots when inoculated. Wart-like protuberance were formed on the surface of apple and pear. Canker appeared on branches of peach and ornamental cherry inoculated.

• Journal of Microbiology and Biotechnology
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• v.26 no.1
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• pp.89-98
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• 2016

Endophytes play an important role in the growth and development of the host. However, the study of endophytes is mostly focused on plants, and reports on bacteria associated with fungi are relatively rare. We studied the bacteria associated with fruiting bodies of Tricholoma matsutake picked from seven main T. matsutake-producing areas in Sichuan, China, by barcoded pyrosequencing. About 8,272 reads were obtained per sample, representing 40 phyla, 103 classes, and 495 genera of bacteria and archaea, and 361-797 operational taxonomic units were observed at a 97% similarity level. The bacterial community was always both more abundant and more diverse than the archaeal community. UniFrac analysis showed there were some difference of bacterial communities among the samples sites. Three bacterial phyla, Proteobacteria, Bacteroidetes, and Firmicutes, were dominant in all samples. Correlation analysis showed there was a significant correlation between some soil properties and bacterial community associated with T. matsutake. This study demonstrated that the bacteria associated with T. matsutake fruiting bodies were diversified. Among these bacteria, we may find some strains that can promote the growth of T. matsutake.