Hyuk Woo Kwon

Detection of Extracellular enzymes Activities in Various Fusarium spp.

Thirty seven species of Fusarium were evaluated for their ability of producing extracellular enzymes using chromogenic medium containing substrates such as starch, cellobiose, CM-cellulose, xylan, and pectin. Among the tested species Fusarium mesoamericanum, F. graminearum, F. asiaticum, and F. acuminatum showed high β-glucosidase acitivity. Xylanase activity was strongly detected in F. proliferatum and oxysporum. Strong pectinase activity was also found in F. oxysporum and F. proliferutum. Amylase activity was apparent in F. oxysporum. No clear activity in cellulase was found from all the Fusarium species tested.

Identification and Characterization of Trichoderma citrinoviride Isolated from Mushroom Fly-Infested Oak Log Beds Used for Shiitake Cultivation

Recently, mushroom flies have been infesting in oak log beds usedfor shiitake cultivation in many mushroom farms all over Korea(Shin et al., 2011). Some shiitake farmers argue that the fly-infestedoak log beds do not produce or reduce the fruiting body of shiitake,resulting in huge economic loss. Other shiitake farmers assume thatthe mushroom fly vectors green mold disease in infested oak logbeds. In an effort to chase the green mold disease, we sampledmushroom fly-infested shiitake log beds from a mushroom farmlocated in Cheonan, Korea in June, 2009. When we debarked thesampled shiitake log bed, the mushroom fly’s larvae were present inthe brown colored log bed (Fig. 1A, B). The fungus DUCC001 wasisolated from the brown colored log bed and deposited at DankookUniversity Culture Collection (DUCC).The fungus DUCC001 produced pale yellow pigment on PDAand formed numerous conidia around inoculums on Czapek yeastextract agar (CYA) (Fig. 1C, D). Optimal growth temperature andpH for the fungus were 30

Extracellular Enzyme Activities of the Monokaryotic Strains Generated from Basidiospores of Shiitake Mushroom

To obtain basic information on the biochemical property of basidiospores of shiitake mushroom (Lentinula edodes), the ability of producing extracellular enzyme was assessed using a chromogenic plate-based assay. For the aim, amylase, avicelase, β-glucosidase, CM-cellulase, pectinase, proteinase, and xylanase were tested against monokaryotic strains generated from forty basidiospores of two different parental dikaryotic strains of shiitake mushroom, Sanjo-101Ho and Sanjo-108Ho. These two parental strains showed different degree of extracellular enzyme activity. No identical patterns of the degree of enzyme activity were observed between monokaryotic strains and parental strains of the two shiitake cultivars. The degree of extracellular enzyme activity also varied among monokaryotic strains of the two shiitake cultivars. Our results showed that dikaryotic parental strains of shiitake mushroom produce monokaryotic basidiospores having very diverse biochemical properties.

Unrecorded Fungal Species Isolated from Greenhouses Used for Shiitake Cultivation in Korea

Fungal contamination is a detrimental factor affecting sawdust media-based shiitake cultivation in greenhouses. During fungal monitoring of greenhouses used for shiitake cultivation, eight fungal species were isolated and identified from indoor air and mushroom flies collected in the greenhouses. The current study reported five species as new in Korea, viz. Ascochyta hordei, Discosia artocreas, Mucor nidicola, Perenniporia medulla-panis, and Pseudozyma prolifica, and confirmed two species, Penicillium charlesii and Penicillium brevicompactum, which were previously recorded in Korea without molecular taxonomic validation. The morphological characteristics and phylogenetic relationships based on nucleotide sequences of the internal transcribed spacer rDNA region or calmodulin gene were described for all identified species.

Genetic and Biochemical Characterization of Monokaryotic Progeny Strains of Button Mushroom (Agaricus bisporus)

Abstract To promote the selection of promising monokaryotic strains of button mushroom (Agaricus bisporus) during breeding, 61 progeny strains derived from basidiospores of two different lines of dikaryotic parental strains, ASI1038 and ASI1346, were analyzed by nucleotide sequencing of the intergenic spacer I (IGS I) region in their rDNA and by extracellular enzyme assays. Nineteen different sizes of IGS I, which ranged from 1,301 to 1,348 bp, were present among twenty ASI1346-derived progeny strains, while 15 different sizes of IGS I, which ranged from 700 to 1,347 bp, were present among twenty ASI1038-derived progeny strains. Phylogenetic analysis of the IGS sequences revealed that different clades were present in both the ASI10388- and ASI1346-derived progeny strains. Plating assays of seven kinds of extracellular enzymes (β-glucosidase, avicelase, CM-cellulase, amylase, pectinase, xylanase, and protease) also revealed apparent variation in the ability to produce extracellular enzymes among the 40 tested progeny strains from both parental A. bisporus strains. Overall, this study demonstrates that characterization of IGS I regions and extracellular enzymes is useful for the assessment of the substrate-degrading ability and heterogenicity of A. bisporus monokaryotic strains.

Biochemical Characterization of Agaricus bisporus Dikaryon Strains

Mushroom Research Division, Department of Herbal Crop Research, National Institute of Horticultural and Medicinal Crop RDA,Eumseong 369-874, KoreaABSTRACT: Button mushroom (Agaricus bisporus) strains from diverse origins were compared in this study to obtain basicinformation on their growth and biochemical properties that are helpful for breeding. Among 31 dikaryotic strains tested, moststrains showed better mycelial growth on oatmeal agar than on MEA and PDA. Mycelia of the mushroom strains revealed β-glucosidase activity the most clearly among the seven extracellular enzymes tested. All the strains showed protease activity, but β-glucosidase activity was found in 27 strains and xylanase activity was found in 30 strains. The activity of avicelase, CM-cellulase,amylase, and pectinase was detected in less than 20 strains. These results implied that enzymatic characteristics could be used asa criterion of strain selection for breeding study.KEYWORDS :

Ribosomal Intergenic Spacer 1 Based Characterization of Button Mushroom (Agaricus bisporus) Strains

Abstract Breeding the button mushroom requires genetic information about its strains. This study was undertaken to genetically characterize four domestically bred button mushroom strains (Saea, Saejung, Saedo, Saeyeon cultivars) and to assess the possibility of using the intergenic spacer 1 (IGS1) region of rDNA as a genetically variable region in the genetic characterization. For the experiment, 34 strains of Agaricus bisporus, two strains of A. bitorquis, and one strain of A. silvaticus, from 17 countries were used. Nucleotide sequence analysis of IGS1 rDNA in these 37 Agaricus strains confirmed that genetic variations exist, not only among the four domestic strains, but also between the four domestic strains and foreign strains. Crossing two different haploid strains of A. bisporus seems to generate genetic variation in the IGS1 region in their off-spring haploid strains. Phylogenetic analysis based on the IGS1 sequence revealed all A. bisporus strains could be differentiated from A. silvaticus and A. bitorquis strains. Five genetic groups were resolved among A. bisporus strains. Saejung and Saeyeon cultivars formed a separate genetic group. Our results suggest that IGS1 could be complementarily applied in the polymorphism analysis of button mushroom.

First Report of Leaf Rust Caused by Puccinia caricis in Farfugium japonicum in Korea

Abstract Farfugium japonicum is used in traditional medicine and as an edible herb in China and Korea. In July 2013, leaf spots were observed in F. japonicum seedlings at Ulleung Island, Gyeongsangbuk Province, Korea. Early symptoms on the leaf adaxial surface included roughly circular yellow spots that later developed brown, necrotic centers. The aecia were hypophyllous, cupulate, yellowish, 180~430 μm in diameter, clustered, and erumpent with a peridium with a recurved margin. The aeciospores were globoid, 14~17 × 13~16 μm, light yellow or colorless, and densely verrucose. The 28S rDNA sequence of the isolate was identical to each other and shared 99% identity with Puccinia caricis. This is the first report of rust caused by P. caricis in F. japonicum in Korea or elsewhere in the world.

Investigation of bacteria in indoor air of a greenhouse for button mushroom cultivation

ABSTRACT: Since button mushroom (Agaricus bisporus) cultivation is performed in closed environment, the understanding ofindoor environment becomes essential for the quality and quantitative production of the greenhouse-grown mushroom. Togenerate information on indoor environmental factors affecting on fruiting body quality, we investigated temperature, humidity,and bacterial concentration and species in a greenhouse located in Buyeo, Chungnam Province. Temperature and humidity wererecorded as 19.75±0.35 O C and 87±3.67%, respectively. The total concentration of bacteria was measured as 3.84×103 CFU / M 3 .Advenella kashmirensis, Bacillus vietnamensism, B. licheniformis, Burkholderia sordidicola, Fictibacillus phosphorivorans, Lysobacterdaejeonensis, Microbacterium esteraromaticum, Pseudomonas aeruginosa, P. protegens, P. gessardii, P. mosseli were identified fromindoor air of the greenhouse. KEYWORDS: Button mushroom, Airborne bacteria, Greenhouse 서론 양송이는 전 세계에서 많은 양이 재배되고 소비되는 버섯 중 하나이다. 식용버섯으로서 양송이는 건조중량 대비19-38%의 단백질을 함유하고 있으며(Braaksma andSchaap, 1996), 재배환경을 조절하여 비타민 D를 생산할수 있는 것으로 보고가 되었다(Koyyalamudi et al, 2009).약리효과로는 양송이 섭취시 혈당과 콜레스테롤 수치 저하에 도움을 준다고 보고가 되었다(Jeong et al, 2010). 양송이는 퇴비배지를 이용하여 재배가 된다. 퇴비배지는 크게 2개 단계로 나누어서 준비가 된다. 첫 단계에서는 재료를 혼합하고 발효시키고 두 번째 단계에서는 발효가 된 배지를 저온살균하고 병원균이 없는 퇴비를 선정한다(Randle and Hayes, 1972; Ross and Harris, 1983;Bech, 1973). 후발효까지 진행된 배지에는 양송이 종균을접종하고 복토 후 재배에 들어간다. 양송이 재배에 있어서 퇴비발효는 중요한 부분을 차지하기 때문에 발효에 관한 연구는 다방면으로 많이 연구가 되어왔고 발효에 관여하는 미생물의 활력에 관해서도 많은 부분이 연구가 되어졌다(Adams and Frostick, 2008).양송이 재배는 외부환경과 차단된 재배사를 이용하여이루어진다. 따라서 환기가 불충분하고 습하며 기온이 높을 경우 재배사내 공기질이 저하되면서 실내공기 중에 부유하는 미생물의 증식이 활발하게 이루어질 수 있다. 미생물이 증식하면 대사 과정에서 생산하는 휘발성 물질에의해 세균을 전파하는 버섯파리 등의 유입이 발생하여 재배하는 버섯 자실체의 오염을 야기할 수 있다. 또한 증식된 미생물은 공기중에 부유하면서 에어로졸로 존재하여그 농도가 높아질 경우 버섯 재배자들이 미생물에 많이노출될 수 있다. 이 경우 호흡기 질환, 알레르기 질환, 인

Characterization of Myrothecium roridum Isolated from Imported Anthurium Plant Culture Medium

Abstract During an investigation of microorganisms and pests in plant culture media from imported anthurium pots, a fungal isolate (DUCC4002) was detected. Based on its morphological characters including colony shape on potato dextrose agar, the microstructures of spores observed by light and scanning electron microscopy and the results of phylogenetic analysis using an internal transcribed spacer rDNA sequence, the fungal isolate was identified as Myrothecium roridum. Pathogenicity testing on anthurium leaves revealed that the fungus could colonize and produce sporodochia on the inoculated leaves. This is the first report of M. roridum detected in imported plant culture medium in Korea.