한국균학회소식:학술대회논문집
The Korean Society of Mycology (KSM)
- 기타
Domain
- Life Science > Phylogenetics/Ecology/Environmentalbiology
2014.10a
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Park, Sook-Young;Choi, Jaehyuk;Choi, Jaeyoung;Kim, Seongbeom;Jeon, Jongbum;Kwon, Seomun;Lee, Dayoung;Huh, Aram;Shin, Miho;Jung, Kyungyoung;Jeon, Junhyun;Kang, Chang Hyun;Kang, Seogchan;Lee, Yong-Hwan 9
Null mutants generated by targeted gene replacement are frequently used to reveal function of the genes in fungi. However, targeted gene deletions may be difficult to obtain or it may not be applicable, such as in the case of redundant or lethal genes. Constitutive expression system could be an alternative to avoid these difficulties and to provide new platform in fungal functional genomics research. Here we developed a novel platform for functional analysis genes in Magnaporthe oryzae by constitutive expression under a strong promoter. Employing a binary vector (pGOF1), carrying$EF1{\beta}$ promoter, we generated a total of 4,432 transformants by Agrobacterium tumefaciens-mediated transformation. We have analyzed a subset of 54 transformants that have the vector inserted in the promoter region of individual genes, at distances ranging from 44 to 1,479 bp. These transformants showed increased transcript levels of the genes that are found immediately adjacent to the vector, compared to those of wild type. Ten transformants showed higher levels of expression relative to the wild type not only in mycelial stage but also during infection-related development. Two transformants that T-DNA was inserted in the promotor regions of putative lethal genes, MoRPT4 and MoDBP5, showed decreased conidiation and pathogenicity, respectively. We also characterized two transformants that T-DNA was inserted in functionally redundant genes encoding alpha-glucosidase and alpha-mannosidase. These transformants also showed decreased mycelial growth and pathogenicity, implying successful application of this platform in functional analysis of the genes. Our data also demonstrated that comparative phenotypic analysis under over-expression and suppression of gene expression could prove a highly efficient system for functional analysis of the genes. Our over-expressed transformants library would be a valuable resource for functional characterization of the redundant or lethal genes in M. oryzae and this system may be applicable in other fungi. -
Fungal pathogens have huge impact on health and economic wellbeing of human by causing life-threatening mycoses in immune-compromised patients or by destroying crop plants. A key determinant of fungal pathogenesis is their ability to undergo developmental change in response to host or environmental factors. Genetic pathways that regulate such morphological transitions and adaptation are therefore extensively studied during the last few decades. Given that epigenetic as well as genetic components play pivotal roles in development of plants and mammals, contribution of microbial epigenetic counterparts to this morphogenetic process is intriguing yet nearly unappreciated question to date. To bridge this gap in our knowledge, we set out to investigate histone modifications among epigenetic mechanisms that possibly regulate fungal adaptation and processes involved in pathogenesis of a model plant pathogenic fungus, Magnaporthe oryzae. M. oryzae is a causal agent of rice blast disease, which destroys 10 to 30% of the rice crop annually. Since the rice is the staple food for more than half of human population, the disease is a major threat to global food security. In addition to the socioeconomic impact of the disease it causes, the fungus is genetically tractable and can undergo well-defined morphological transitions including asexual spore production and appressorium (a specialized infection structure) formation in vitro, making it a model to study fungal development and pathogenicity. For functional and comparative analysis of histone modifications, a web-based database (dbHiMo) was constructed to archive and analyze histone modifying enzymes from eukaryotic species whose genome sequences are available. Histone modifying enzymes were identified applying a search pipeline built upon profile hidden Markov model (HMM) to proteomes. The database incorporates 22,169 histone-modifying enzymes identified from 342 species including 214 fungal, 33 plants, and 77 metazoan species. The dbHiMo provides users with web-based personalized data browsing and analysis tools, supporting comparative and evolutionary genomics. Based on the database entries, functional analysis of genes encoding histone acetyltransferases and histone demethylases is under way. Here I provide examples of such analyses that show how histone acetylation and methylation is implicated in regulating important aspects of fungal pathogenesis. Current analysis of histone modifying enzymes will be followed by ChIP-Seq and RNA-seq experiments to pinpoint the genes that are controlled by particular histone modifications. We anticipate that our work will provide not only the significant advances in our understanding of epigenetic mechanisms operating in microbial eukaryotes but also basis to expand our perspective on regulation of development in fungal pathogens.
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Species belonging to the genus Fusarium are widely distributed and cause diseases in many plants. Isolation of fungal strains from air or cereals is necessary for disease forecasting, disease diagnosis, and population genetics [1]. Previously we showed that Fusarium species are resistant to toxoflavin produced by the bacterial rice pathogen Burkholderia glumae while other fungal genera are sensitive to the toxin, resulting in the development of a selective medium for Fusarium species using toxoflavin [2]. In this study, we have tried to elucidate the resistant mechanism of F. graminearum against toxoflavin and interaction between the two pathogens in nature. To test whether B. glumae affects the development of F. graminearum, the wild-type F. graminearum strains were incubated with either the bacterial strain or supernatant of the bacterial culture. Both conditions increased the conidial production five times more than when the fungus was incubated alone. While co-incubation resulted in dramatic increase of conidial production, conidia germination delayed by either the bacterial strain or supernatant. These results suggest that certain factors produced by B. glumae induce conidial production and delay conidial germination in F. graminearum. To identify genes related to toxoflavin resistance in F. graminearum, we screened the transcriptional factor mutant library previously generated in F. graminearum [3] and identified one mutant that is sensitive to toxoflavin. We analyzed transcriptomes of the wild-type strain and the mutant strain under either absence or presence of toxoflavin through RNAseq. Expression level of total genes of 13,820 was measured by reads per kilobase per million mapped reads (RPKM). Under the criteria with more than two-fold changes, 1,440 genes were upregulated and 1,267 genes were down-regulated in wild-type strain than mutant strain in response to toxoflavin treatment. A comparison of gene expression profiling between the wild type and mutant through gene ontology analysis showed that genes related to metabolic process and oxidation-reduction process were highly enriched in the mutant strain. The data analyses will focus on elucidating the resistance mechanism of F. graminearum against toxoflavin and the interaction between the two pathogens in rice. Further evolutionary history will be traced through figuring out the gene function in populations and in other filamentous fungi.
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Fusarium graminearum (teleomorph Gibberella zeae) is an important plant pathogen that causes head blight of major cereal crops such as wheat, barley, and rice, as well as causing ear and stalk rot on maize worldwide. Plant diseases caused by this fungus lead to severe yield losses and accumulation of harmful mycotoxins in infected cereals [1]. Fungi utilize spore production as a mean to rapidly avoid unfavorable environmental conditions and to amplify their population. Spores are produced sexually and asexually and their production is precisely controlled. Upstream developmental activators consist of fluffy genes have been known to orchestrate early induction of condiogenesis in a model filamentous fungus Aspergillus nidulans. To understand the molecular mechanisms underlying conidiogenesis in F. graminearum, we characterized functions of the F. graminearum fluffy gene homologs [2]. We found that FlbD is conserved regulatory function for conidiogenesis in both A. nidulans and F. graminearum among five fluffy gene homologs. flbD deletion abolished conidia and perithecia production, suggesting that FlbD have global roles in hyphal differentiation processes in F. graminearum. We further identified and functionally characterized the ortholog of AbaA, which is involved in differentiation from vegetative hyphae to conidia and known to be absent in F. graminearum [3]. Deletion of abaA did not affect vegetative growth, sexual development, or virulence, but conidium production was completely abolished and thin hyphae grew from abnormally shaped phialides in abaA deletion mutants. Overexpression of abaA resulted in pleiotropic defects such as impaired sexual and asexual development, retarded conidium germination, and reduced trichothecene production. AbaA localized to the nuclei of phialides and terminal cells of mature conidia. Successful interspecies complementation using A. nidulans AbaA and the conserved AbaA-WetA pathway demonstrated that the molecular mechanisms responsible for AbaA activity are conserved in F. graminearum as they are in A. nidulans. F. graminearum ortholog of Aspergillus nidulans wetA has been shown to be involved in conidiogenesis and conidium maturation [4]. Deletion of F. graminearum wetA did not alter mycelial growth, sexual development, or virulence, but the wetA deletion mutants produced longer conidia with fewer septa, and the conidia were sensitive to acute stresses, such as oxidative stress and heat stress. Furthermore, the survival rate of aged conidia from the F. graminearum wetA deletion mutants was reduced. The wetA deletion resulted in vigorous generation of single-celled conidia through autophagy-dependent microcycle conidiation, indicating that WetA functions to maintain conidia dormancy by suppressing microcycle conidiation in F. graminearum. In A. nidulans, FlbB physically interacts with FlbD and FlbE, and the resulting FlbB/FlbE and FlbB/FlbD complexes induce the expression of flbD and brlA, respectively. BrlA is an activator of the AbaA-WetA pathway. AbaA and WetA are required for phialide formation and conidia maturation, respectively [5]. In F. graminearum, the AbaA-WetA pathway is similar to that of A. nidulans, except a brlA ortholog does not exist. Amongst the fluffy genes, only fgflbD has a conserved role for regulation of the AbaA-WetA pathway.
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Pleurotus ostreatus, P. eryngii, and Flammulina velutipes are major edible mushrooms that account for over 89% of total mushroom production in Korea. Recently, Agrocybe cylindracea, Hypsizygus marmoreus, and Hericium erinaceu are increasingly being cultivated in mushroom farms. In Korea, the production of edible mushrooms was estimated to be 614,224 ton in 2013. Generally, about 5 kg of mushroom substrate is needed to produce 1 kg of mushroom, and consequently about 25 million tons of spent mushroom substrate (SMS) is produced each year in Korea. Because this massive amount of SMC is unsuitable for reuse in mushroom production, it is either used as garden fertilizer or deposited in landfills, which pollutes the environment. It is reasonably assumed that SMS includes different secondary metabolites and extracellular enzymes produced from mycelia on substrate. Three major groups of enzymes such as cellulases, xylanases, and lignin degrading enzymes are involved in breaking down mushroom substrates. Cellulase and xylanase have been used as the industrial enzymes involving the saccharification of biomass to produce biofuel. In addition, lignin degrading enzymes such as laccases have been used to decolorize the industrial synthetic dyes and remove environmental pollutions such as phenolic compounds. Basidiomycetes produce a large number of biologically active compounds that show antibacterial, antifungal, antiviral, cytotoxic or hallucinogenic activities. However, most previous researches have focused on therapeutics and less on the control of plant diseases. SMS can be considered as an easily available source of active compounds to protect plants from fungal and bacterial infections, helping alleviate the waste disposal problem in the mushroom industry and creating an environmentally friendly method to reduce plant pathogens. We describe extraction of lignocellulytic enzymes and antimicrobial substance from SMSs of different edible mushrooms and their potential applications.
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The importance of utilizing biological resources has become magnified and it has been a big issue to share the benefit among nations as Nagoya Protocol began in 2010. This study was conducted to research the diversity and distribution of wild mushrooms, and to survey the traditional mushroom knowledge of the people in Jejudo which is a volcanic island having a distinctive climate and forest environment. The research sites were Dongbaekdongsan, Keuneonggot, Hallasan National Park, Muryeongarioreum, Saryeonisupgil and other important area where mushrooms are growing spontainously in Jejudo. A total of 511 species comprising 2 phylums, 8 classes, 20 orders and 74 genera were identified from 1600 specimens collected from 2006 to 2012. In previous studies, a total of 561 species comprising 69 families and 99 genera were investigated. As a result, a total of 755 species comprising 23 orders, 87 families and 263 genera were documented in Jejudo. In this study, 137 species were newly identified as unrecorded species in Jejudo and 9 species, Amanita gemmata, Tricholoma aurantiipes, Panellus violaceofulvus, Leucopaxillus septentrionalis, Bondarzewia montana, Psilocybe argentipes, Boedijnopeziza insititia, Sarcoscypha occidentalis for. occidentalis and Morchella patula var. semilibera were the first record for Korea. Also, 7 species, Amanita gemmata, Tricoloma aurantiipes, Panellus violaceofulvus, Leucopaxillus septentrionalis, Boedijnopeziza insititia, Sarcoscypha occidentalis for. occidentalis and Morchella patula var. semilibera were known as only growing in Jejudo. The traditional knowledge was collected from visiting and questionnaire survey in 50 villages in Jejudo. A total of 23 mushrooms were found in which 12 species were used for food, 2 species were poisonous, 6 species were medicinal, 2 species were used for folk religion and 3 species were used for play purposes. Macrolepiota procera was the most commonly used as an edible mushroom and Chlorophyllum neomastoidea was the most well known poisonous mushroom. Also, 267 cases of traditional knowledge about using mushrooms as a food and medicine were collected. This study has significance for supplementing previous studies about distribution of wild mushrooms in Jejudo and documenting unrecorded species in Korea. Also, it is valuable by providing important data of traditional knowledge for using mushrooms since old times.
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There are many yeast strains have been discovered for industrial usage in global scale. In the point of view for the alcoholic fermentation performance and producing alcoholic beverage products, recently many countries have known about the importance of microorganisms as a valuable resource. Discovered with well performed yeasts have potential industrial application in diverse ways such as foods, beverages, cosmetics, pharmaceutical functions, and so on. In Korea, the yeast research has not been sufficiently performed especially for distilled spirits industry. As a result, not so little manufacturers use exotic yeasts from overseas even included the expensive royalties. Besides of those, to produce distilled spirits, many manufacturers do not use specialized yeast for distilled spirits. Distiller's characterized yeasts such as whisky, brandy, vodka, Japanese shochu and awamori, are all well-known industrialized. For decades, the distillers, except us, have selected, developed, and practised yeasts in accordance with distilled spirits characters. This study is about selection and industrial application of yeasts for the Korean pot distilled spirits. Finally 7 yeast strains were selected among over 1,000 yeasts from the traditional Nuruks, through the essential related tests based on brewing and distilling science. The selected yeasts show the appropriate characteristics of distilled spirits. The result of this study could help our distilled spirits industry be activated and stand independent from the exotic microbes.
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Three species of Fusarium, F. fujikuroi, F. verticillioides and F. proliferatum, are known to be associated with bakanae disease of rice [1, 2]. F. fujikuroi infects rice flowers and survive in endosperm and embryo of the seeds. Infected seed is an important source of primary inoculum of pathogens [3]. Seeds of rice (Oryza sativa cv. Boramchan) collected from bakanae-infected field were found to be 96% infected with Fusarium sp., 52% with F. fujikuroi, 42% with F. verticillioides, and 12% with F. proliferatum as determined by incubation method and species-specific PCR assays. F. fujikuroi was detected at lemma/palea, endosperm and embryo whereas F. verticillioides and F. proliferatum were recovered only from lemma/palea by means of component plating test. Seed disinfection methods have been developed to control bakanae disease and prochloraz has been most widely used for rice seeds. Two chemicals formulated with prochloraz (PC 1) and prochloraz + hexaconazole (PC 2) that inhibit biosynthesis of ergosterol strongly reduced the incidence of Fusarium spp. on selective media to 4.7% and 2.0%, respectively. Disease symptoms of rice seedlings in nursery soil were alleviated by chemical treatment; seedlings with elongated leaves or wide angle between leaf and stem were strikingly reduced from 15.6 to 3.2% (PC 1) and 0 (PC 2), stem rots were reduced from 56.9 to 26.2% (PC 1) and 32.1% (PC 2), and normal seedling increased from 0.4 to 13.3% (PC 2). Prochloraz has some disadvantages and risks such as the occurrence of tolerant pathogens [4] and effects on the sterol synthesis in animals and humans [5]. For these reasons, it is necessary to develop new disinfection method that do not induce fungal tolerance and are safe to humans and animals. Chlorine dioxide (
$ClO_2$ ), that is less toxic, produces no harmful byproducts, and has high oxidizing power, has been reported to be effective at disinfection of several phytopathogenic fungi including Colletotrichum spp. and Alternaria spp. [6]. Gaseous$ClO_2$ applied to rice seeds at a concentration of 20 ppm strongly suppressed mycelial growth of Fusarium fujikuroi, F. verticillioides and F. proliferatum. The incidence of Fusarium spp. in dry seed with 8.7% seed moisture content (SMC) tended to decrease as the concentration of$ClO_2$ increased from 20 to 40 ppm. Applying 40 ppm$ClO_2$ at 90% relative humidity, incidence was reduced to 5.3% and resulted in significant reduction of disease symptoms on MS media. In nursery soil, stem rot was reduced from 56.9 to 15.4% and the number of normal seedlings increased from 0.4 to 25.5%. With water-soaked seeds (33.1% SMC) holding moisture in the endosperm and embryo, the effectiveness of disinfection using$ClO_2$ increased, even when treated with only 20 ppm for four hours. This suggests that moisture was a key element for action of$ClO_2$ . Removal of the palea and lemma from seeds significantly decreased the incidence of Fusarium spp. to 3.0%. Seed germination appeared to decrease slightly by water-soaking at$30^{\circ}C$ because of increased SMC and by physical damage of embryos from hulling. These results indicate that the use of gaseous$ClO_2$ was effective as a means to disinfect rice seeds infected with Fusarium spp. and that moisture around the pathogens in the seed was an important factor for the action of$ClO_2$ . Further investigations should be conducted to ascertain the best conditions for complete disinfection of Fusarium spp. that infect deep site of rice seeds. -
Since Darwin and Wallace introduced the concept on the evolution of species, scientists have been furiously debating what species are, and how to define them. This basic yet intriguing question has bothered us ever since, as communicating to fellow biologists about fungal species is the very cornerstone of mycology. For the species presently known, this has largely been accomplished via Latin binomials linked to morphology in the absence of DNA barcodes. In recent years mycologists have embraced the ribosomal ITS as official barcode region for Fungi, and this locus is also mainly used in environmental pyrosequencing studies. Furthermore, DNA data can now also be used to describe sterile species in the absence or lack of distinct morphological structures. Recent developments such as the registration of names in MycoBank, and linking the phenotype to the genotype, have significantly changed the face of fungal systematics. By employing the Consolidated Species Concept, incorporating genealogical concordance, ecology and morphology, robust species recognition is now possible. Several international initiatives have since built on these developments, such as the DNA barcoding of holdings of Biological Resource Centres, followed by the Genera of Fungi Project, aiming to recollect, and epitypify all type species of all genera. What these data have revealed, is that most genera are poly- and paraphyletic, and that morphological species normally encompass several genetic entities, which may be cryptic species. Once we provide a stable genetic backbone capturing our existing knowledge of the past 250 years, we will be able to accommodate novelties obtained via environmental sequencing platforms. Being able to communicate these species to other biologists in a clear manner that is DNA-based, will enable scientists to elucidate the importance, role and ecological interactions that these fungi have on our planet.
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Meju is a brick of dried fermented soybeans and is the core material for Jang such as Doenjang and Ganjang. Jang is produced by addition of salty water to Meju and is considered the essential sauces of authentic Korean cuisine. Meju is fermented by diverse microorganisms such as bacteria, fungi and yeasts. It is known that fungi play an important role in the Meju fermentation and they degrade macromolecules of the soybeans into small nutrient molecules. In previous study, 26 genera and 0 species were reported as Meju fungi. However, it is not comprehensively examined where the fungi present on the Meju are originated. In order to elucidate the origin of the fungi present on the Meju, the mycobiota of 500 samples soybean kernels, 296 rice straw pieces and air samples of Jang factories was determined in 0, 2 and 7 Jang factories respectively. Forty-one genera covering 86 species were isolated from the soybeans and 33 species were identical with the species from Meju. From sodium hypochlorite untreated soybeans, Eurotium herbariorum, Eurotium repens, Cladosporium tenuissimum, Fusarium fujikuroi, Aspergillus oryzae/flavus and Penicillium steckii were the predominant species. In case of sodium hypochlorite-treated soybeans, Eurotium herbariorum, E. repens and Cladosporium tenuissimum were the predominant species. Of the 4 genera and 86 species isolated from soybeans, 3 genera and 33 species were also found in Meju. Thirty-nine genera and 92 species were isolated from the rice straws and 40 species were identical with the species from Meju. Fusarium asiaticum, Cladosporium cladosporioides, Aspergillus tubingensis, A. oryzae, E. repens and Eurotium chevalieri were frequently isolated from the rice straw obtained from many factories. Twelve genera and 40 species of fungi that were isolated in the rice straw in this study, were also isolated from Meju. Especially, A. oryzae, C. cladosporioides, E. chevalieri, E. repens, F. asiaticum and Penicillium polonicum that are abundant species in Meju, were also isolated frequently from rice straw. C. cladosporioides, F. asiaticum and P. polonicum that are abundant in low temperature fermentation process of Meju fermentation, were frequently isolated from rice straw incubated at
$5^{\circ}C$ and$25^{\circ}C$ , while A. oryzae, E. repens and E. chevalieri that are abundant in high temperature fermentation process of Meju fermentation, were frequently isolated from rice straw incubated at$25^{\circ}C$ and$35^{\circ}C$ . This suggests that the mycobiota of rice straw have a large influence in mycobiota of Meju. Thirty-nine genera and 92 species were isolated from the air of Jang factories and 34 species were identical with the species from Meju. In outside air of the fermentation room, Cladosporium sp. and Cladosporium cladosporioides were the dominant species, followed by Cladosporium tenuissimum, Eurotium sp., Phoma sp. Sistotrema brinkmannii, Alternaria sp., Aspergillus fumigatus, Schizophyllum commune, and Penicillium glabrum. In inside air of the fermentation room, Cladosporium sp., Aspergillus oryzae, Penicillium chrysogenum, A. nidulans, Aspergillus sp., C. cladosporioides, Eurotium sp., Penicillium sp., C. tenuissimum, A. niger, E. herbariorum, A. sydowii, and E. repens were collected with high frequency. The concentrations of the genus Aspergillus, Eurotium and Penicillium were significantly higher in inside air than outside air. From this results, the origin of fungi present on Meju was inferred. Of the dominant fungal species present on Meju, Lichtheimia ramosa, Mucor circinelloides, Mucor racemosus, and Scopulariopsis brevicaulis are thought to be originated from outside air, because these species are not or are rarely isolated from rice straw and soybean; however, they were detected outside air of fermentation room and are species commonly found in indoor environments. However, A. oryzae, P. polonicum, E. repens, P. solitum, and E. chevalieri, which are frequently found on Meju, are common in rice straw and could be transferred from rice straw to Meju. The fungi grow and produce abundant spores during Meju fermentation, and after the spores accumulate in the air of fermentation room, they could influence mycobiota of Meju fermentation in the following year. This could explain why concentrations of the genus Aspergillus, Eurotium, and Penicillium are much higher inside than outside of the fermentation rooms. -
Filamentous fungi of the genus Colletotrichum (teleomorph, Glomerella) are considered major plant pathogens worldwide. Cereals, legumes, vegetables, and fruit trees may be seriously affected by this pathogen (1). Colletotrichum species cause typical disease symptoms known as anthracnoses, characterized by sunken necrotic tissue, where orange conidial masses are produced. Anthracnose appears in both developing and mature plant tissues (2). We investigated disease occurrence in apple orchards from 2013 to 2014 in northern Gyeongbuk province, Korea. Typical anthracnose with advanced symptoms was observed in all apple orchards studied. Of late, static fruit spot symptoms are being observed in apple orchards. A small lesion, which does not expand further and remains static until the harvesting season, is observed at the beginning of fruit growth period. In our study, static symptoms, together with the typical symptoms, were observed on apples. The isolated fungus was tested for pathogenicity on cv. 'Fuji apple' (fully ripe fruits, unripe fruits, and cross-section of fruits) by inoculating the fruits with a conidial suspension (
$10^5$ conidia/ml). In apple inoculated with typical anthracnose fungus, the anthracnose symptoms progressed, and dark lesions with salmon-colored masses of conidia were observed on fruit, which were also soft and sunken. However, in apple inoculated with fungi causing static symptoms, the size of the spots did not increase. Interestingly, the shape and size of the conidia and the shape of the appressoria of both types of fungi were found to be similar. The conidia of the two types of fungi were straight and cylindrical, with an obtuse apex. The culture and morphological characteristics of the conidia were similar to those of C. gloeosporioides (5). The conidia of C. gloeosporioides germinate and form appressoria in response to chemical signals such as host surface wax and the fruitripening hormone ethylene (3). In this study, the spores started to germinate 4 h after incubation with an ethephon suspension. Then, the germ tubes began to swell, and subsequently, differentiation into appressoria with dark thick walls was completed by 8 h. In advanced symptoms, fungal spores of virtually all the appressoria formed primary hyphae within 16 h. However, in the static-symptom fungus spores, no primary hyphae formed by 16 h. The two types of isolates exhibited different growth rates on medium containing apple pectin, Na polypectate, or glucose as the sole carbon. Static-symptom fungi had a >10% reduction in growth (apple pectin, 14.9%; Na polypectate, 27.7%; glucose, 10.4%). The fungal isolates were also genetically characterized by sequencing. ITS regions of rDNA, chitin synthase 1 (CHS1), actin (ACT), and${\beta}$ -tubulin (${\beta}t$ ) were amplified from isolates using primer pairs ITS 1 and ITS 4 (4), CHS-79F and CHS-354R, ACT-512F and ACT-783R, and T1 and${\beta}t2$ (5), respectively. The resulting sequences showed 100% identity with sequences of C. gloeosporioides at KC493156, and the sequence of the${\beta}$ t gene showed 100% identity with C. gloeosporioides at JX009557.1. Therefore, sequence data from the four loci studied proves that the isolated pathogen is C. gloeosporioides. We also performed random amplified polymorphic DNA-PCR, which showed clearly differentiated subgroups of C. gloeosporioides genotypes. The clustering of these groups was highly related to the symptom types of the individual strains. -
Apple blotch, caused by Marssonina coronaria, induce early defoliation in apple and leading to critical economic losses in apple orchards in Korea. Since M. coronaria is difficult to culture, we developed isolation and cultural method. We collected M. coronaria isolates from Gyeongbuk Province and then constructed phylogentic tree based on ITS regions. As the results, phylogenetic relationship indicated that all Korean isolates formed a same cluster and closely related to Chinese isolates [1]. Ecological characteristic of M. coronaria have been observed in apple orchards which located in Gyeongbuk Province from 2011 to present. As the results, the typical apple blotch symptoms were observed from July, and then the infected leaves were discolored and formed acervuli on the leaves. After rainfall, severe infection of symptoms such as discoloration and early defoliation were continuously observed until October. Also overwintered conidia were observed in next March on the fallen diseased leaves [2]. In the last 5 years, ascopores of M. coronaria were not observed in apple orchards which were severely infected by M. coronaria in Korea. Thus, it is assumed that overwintered conidia could be a primary inoculum of M. coronaria. Meanwhile, apple blotch has long latent periods compare to other apple disease. During the latent period, early diagnosis of apple blotch is the most important to control the disease by spray fungicide. In this reason, we developed novel diagnostic method to detect M. coronaria during latent period using optical coherence tomography (OCT) and Loop-mediated isothermal amplification (LAMP) method [2, 3]. In this presentation, it will introduce ecological characterization of M. coronaria in Korea and unique detection technique of M. coronaria in apple. It will be helpful to develop new strategies to control apple blotch in Korea.
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Agaricus bisporus, commonly known as the button mushroom, is the most widely cultivated species of edible fungi. Low frequency of recombination ratio and homokaryotic or monokaryotic spore on meiotic basidia form obstacles for breeding programs. Since the first hybrid varieties for white button mushrooms were released in Europe, new varieties released afterwards were either identical of very similar to these first hybrids on morphologies. Therefore, different DNA markers have been used to define unique varieties of A. bisporus strains. Aim of this study is to assess the genetic diversity of different A. bisporus strains in Korea. Twelve UFP (Universal fungal primer, JK BioTech. Ltd), 12 simple sequence repeat (ISSR) and 30 SSR primers were used to assess genetic diversity of monokaryotic and dikaryotic Agaricus bisporus strains including other 19 Agaricus spp. Of them, four UFP, four SSR primers,
$(GA)_8T$ ,$(AG)_8YC$ ,$(GA)_8C$ and$(CTC)_6$ and seven SSR markers produced PCR polymorphic bands between the Agaricus species or within A. bisporus strains. PCR polymorphic bands were inputted for UPGMA cluster analysis. Forty five strains of A. bisporus are genetically clustered into 6 groups, showing coefficient similarity from 0.75 to 0.9 among them. In addition, genetic variations of monokaryotic and dikaryotic Agaricus bisporus strains were partially detected by PCR technologies of this study. The varieties, Saea, saedo, Saejeong and Saeyeon that have recently been developed in Korea were involved in the same group with closely genetic relationship of coefficient similarity over 0.96, whereas, other strains were genetically related to A. bisporus strains that were introduced from USA, Eroupe and Chinese. -
Mating of tetrapolar mushrooms is regulated by to chromosomal loci, A and B. A locus contains A gene that expresses a homeodomain protein whereas B locus contains multiple pheromones and receptor genes. In order to characterize the mating loci in Korean cultivated strains of Lentinula edodes, one hundred monokaryotic myclelia were isolated from the basidiospores of cultivated strains, including Cham-A-Ram, Sanjo701, and Sanjo707. Both mating loci were amplified using primer sets targeting conserved sequence regions for homeodomain (HD), pheromone, and receptor genes. Subsequent sequence analysis revealed that the Korean strains contained significant variations in the homeodomain of A locus, even within the same A1 or A2 mating type. Similarly, B locus was also highly diversified in the sequences of pheromones and receptors as well as gene organization. These results enabled us to design mating type-specific probes which can distinguish mating type of each strain. The specificity was confirmed by between intra- and inter-strain mating experiment.
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The rice blast disease caused by of Magnaporthe oryzae is one of the most destructive diseases of rice. By the microarray analysis, we profiled expression changes of genes during conidiation and found out many putative genes that are up-regulated. Among those, we first selected MGG_06399 encoding a dual-specificity tyrosine-regulated protein kinase (DYRK), homologous to YAK1 in yeast. To investigate functional roles of MoYAK1, We made
${\Delta}Moyak1$ mutants by homology dependent gene replacement. The deletion mutant showed a remarkable reduction in conidiation and produced abnormally shaped conidia smaller than those of wild type. The conidia form${\Delta}Moyak1$ were able to develop a germ tube, but failed to form apppressoria on a hydrophobic coverslip. The${\Delta}Moyak1$ formed appressria on a hydrophobic cover slip when exogenous cAMP was induced, but the appressoria shape was abnormal. The${\Delta}Moyak1$ also formed appressoria abberent in shape on onion epidermis and rice sheaths and failed to penetrate the surface of the plants. These data indicate that MoYAK1 is associated with cAMP/PKA pathway and important for conidiation, appressorial formation and pathogenic development in Magnaporthe oryzae. Detailed characterization of MoYAK1 will be presented. -
Yeasts were isolated from wild flowers of some islands and mountains such as Jeju-do, Ulleungdo, Yokjido, Seonyudo and Gyejoksan, Oseosan, Beakamsan and Deogyusan in Korea and were identified by comparison of nucleotide sequences for PCR-amplified D1/D2 region of 26S rDNA or internal transcribed pacer(ITS) 1 and 2 including 5.8S rDNA using BLAST. Seventy two yeast strains of two hundred eighty nine species were isolated from wild flowers in islands and mountains, Korea. Among them, Cryptococcus species were isolated the most dominantly, and Metschnikowia reukaufii were also isolated thirty species, 10.3% of total strains. Twenty-three species including Cryptococcus aureus were overlapped between yeast strains of the islands and mountains. Some physiological functionality of the culture broth and cell-free extracts from two hundred eighty nine yeast strains were determined. The supernatant of Candida sp. 78-J-2 showed antioxidant activity of 22.5%, and supernatant of Metschnilowia reukaufii SY44-6 showed anti-gout xanthine oxidase inhibitory activity of 49.6% and whitening tyrosinase inhibitory activity of 38.4%, respectively.
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Dokdo island is located in the northeastern part of Ulleungdo, known as volcanic island. In total, 53 fungal isolates were isolated from Dokdo island soil sample, using dilution plate technique. The isolates were identified on the basis of morphological characteristics and rDNA ITS sequence analysis. Out of them, 41 isolates were identified at the level of species. The dominant fungal species and genera included Fusarium spp., Mucor sp., Clonostachys spp., and Trichoderma sp. The % sequence identity (the number of matches/the complete alignment length) values via NCBI BLAST searching of EML-IF9, EML-MF30-1 and EML-DDSF4 represented 97.19% (485/499) with Clonostachys cf. rosea (GenBank accession no. KC313107), 98.33% (472/480) with Metarhizium guizhouense (GenBank accession no. HM055445), and 100% (350/350) with Mortierella oligospora (GenBank accession no. JX976032), respectively. Three species of C. rosea, M. guizhouense and M. oligospora represented new records of fungi from Dokdo island, Korea. The antimicrobial activities of the fungal strains varied with tested. Two isolates (EML-MFS30-1 and EML-IF9) showed antifungal activity against several fungi including Fusarium oxysporum and Rhizotonia solani. Clonostachys rosea (EML-IF9) showed strong hydrolytic enzyme activity. Our results showed that the antagonistic fungi including Clonostachys rosea will be used as potential biocontrol agents for control of fungal diseases.
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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.
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Yadav, Dil Raj;Kim, Sang Woo;Adhikari, Mahesh;Babu, Anam Giridhar;Um, Yong Hyun;Gim, Eun Bi;Yang, Jae Seok;Lee, Hyug Goo;Lee, Youn Su 49
In order to find indigenous beneficial fungal species from crop field soils of Nigeria, 23 soil samples were collected from various places of Nigeria in June, 2013 and fungi were isolated through serial dilution technique. Isolated fungi were purified and differentiated according to their morphological and microscopic characteristics. In total, 38 different representative isolates were recovered and the genomic DNA of each isolates was extracted using QIAGEN$^{(R)}$ Plasmid Mini Kit (QIAGEN Sciences, USA) and the identification of fungi was carried out by sequence analysis of internal transcribed spacer (ITS) region of the 18S ribosomal DNA (18S rDNA). Recovered isolates belonged to 9 fungal genera comprising Fusarium, Aspergillus, Chaetomium, Coniothyrium, Dipodascaceae, Myrothecium, Neosartorya, Penicillium and Trichoderma. Aspergillus spp., Penicillium spp. and Trichoderma spp. were the most dominant taxa in this study. The antagonistic potentiality of species belonged to Trichoderma against 10 phytopathogenic fungi (F. oxysporum, C. gloesporoides, P. cytrophthora, A. alternata, A. solani, S. rolfsii, F. solani, R. solani, S. sclerotiorum and P. nicotiana) was assessed in vitro using dual culture assay. The dual culture assay results showed varied degree of antagonism against the tested phytopathogens. The potential Trichoderma spp. will be further evaluated for their antagonistic and plant growth promotion potentiality under in vivo conditions. -
In this study, we used pyrosequencing method to analysis of soil fungal communities on the Ulleungdo and Dokdo islands. 768 operational taxonomic units (OTUs) were analyzed from the Ulleungdo sample and 640 OTUs and 382 OTUs were analyzed from the Dongdo and Seodo samples, respectively. Compared to the species richness of Ulleungdo and the Dokdo sample, the Ulleungdo sample was higher than in the Dongdo and Seodo samples. Species diversity was much the same. The phylum Basidiomycota was dominant in the Ulleungdo sample, while the phylum Ascomycota was dominant in the Dongdo sample.