研究者データベース

JUNG GEUNHWA(ユング グヌワ)
農学研究院 食水土資源グローバルセンター
教授

基本情報

所属

  • 農学研究院 食水土資源グローバルセンター

職名

  • 教授

ホームページURL

J-Global ID

研究キーワード

  • Plant genomics/genetics/breeding   Fungal genetics   Population dynamics   Drug metabolism/discovery   Drug resistance mechanism/xenobiotic detoxification   

研究分野

  • 環境・農学 / 作物生産科学 / Plant Breeding/Genetics; Comparative Genomics
  • ナノテク・材料 / 生物分子化学 / Drug Discovery
  • 環境・農学 / 化学物質影響 / Drug Resistance; Drug Metabolism
  • 環境・農学 / 植物保護科学 / Fungal Genetics/Biology

職歴

  • 2017年01月 - 現在 University of Massachusetts Amherst Journal of Crop Science Associate Editor
  • 2000年01月 - 2006年05月 University of Wisconsin-Madison Plant Pathology Department Assistant Professor
  • 1995年01月 - 1999年10月 University of Wisconsin-Madison Horticulture Department Post-Doc Researcher and Senior Scientist

学歴

  • 1989年01月 - 1995年05月   University of Nebraska-Lincoln   Plant Breeding and Genetics   Ph.D.

所属学協会

  • American Phytopathological Society   Crop Science Society of America   

研究活動情報

論文

  • Jaemin Lee, Michaela R. Elliott, Toshihiko Yamada, Geunhwa Jung
    Plant Disease PDIS - 06 2021年05月04日 
    Dollar spot, caused by Clarireedia spp. (formerly Sclerotinia homoeocarpa F.T. Bennett), is the most economically important turfgrass disease causing considerable damage on golf courses. While cultural practices are available for reducing dollar spot infection, chemical fungicide use is often necessary for maintaining optimal turf quality. Since the release of boscalid in 2003, the succinate dehydrogenase inhibitor (SDHI) class has become an invaluable tool for managing dollar spot. However, resistance to this class has recently been reported in Clarireedia spp. and many other plant pathogenic fungi. After SDHI field failure on four golf courses and one university research plot, a total of six unique SDH mutations conferring differential in vitro sensitivities to SDHIs have been identified in Clarireedia spp. In 2018 and 2019, turf research plots were inoculated with sensitive, non-mutated isolates of Clarireedia spp., as well as resistant isolates harboring each unique identified mutation. Fungicide efficacy trials were conducted on inoculated plots to assess differential sensitivity to five SDHI active ingredients (boscalid, fluxapyroxad, isofetamid, fluopyram, and pydiflumetofen) across mutations under field conditions. Results indicate unique mutations are associated with distinct SDHI field efficacy profiles as shown in in-vitro sensitivity assays. Isolate populations with B subunit mutations (H267Y/R) were more sensitive to fluopyram, whereas isolate populations with C subunit mutations (C-G91R, C-G150R) showed resistance to all SDHIs tested. Mutation-associated differential sensitivity observed under field conditions indicates a need for a nation-wide survey and frequent monitoring of SDHI sensitivity of dollar spot populations on golf courses in the USA. Further, the information gained from this study will be useful in providing sustainable management recommendations for controlling site-specific resistant populations of Clarireedia spp.
  • A method for the examination of SDHI fungicide resistance mechanisms in phytopathogenic fungi using a heterologous expression system in Sclerotinia sclerotiorum.
    Jingyu Peng, Hyunkyu Sang, Tyre Proffer, Jacqueline Gleason, Cory Outwater, Geunhwa Jung, George W. Sundin
    Phytopathology 111 5 819 - 830 2021年04月 [査読有り]
  • Jaemin Lee, Michaela R. Elliott, Minsoo Kim, Toshihiko Yamada, Geunhwa Jung
    Plant Disease 105 3 660 - 666 2021年03月 
    Dollar spot, caused by the ascomycete fungus Clarireedia (formerly Sclerotinia), is one of the most resource-demanding diseases on amenity turfgrasses in North America. Differential resistance to the succinate dehydrogenase inhibitor (SDHI) fungicide class, conferred by singular point mutations on the SdhB, SdhC, and SdhD subunits of the succinate dehydrogenase enzyme (SDH), has been reported in dollar spot as well as many other plant-pathogenic fungal diseases. Four unique mutations were previously reported from Clarireedia field isolates collected from two different cool-season golf courses in Japan and Rhode Island: an amino acid substitution H267Y and a silent mutation (CTT to CTC) at codon 181 on the SdhB subunit gene, and amino acid substitutions G91R and G150R on the SdhC subunit gene. To properly diagnose and monitor SDHI resistance in the field, a rapid detection system for known mutations is crucial. As part of this study, additional SDHI-resistant Clarireedia isolates were collected from Rutgers University research plots and in vitro sensitivity to four SDHI active ingredients was assessed. SdhB, SdhC, and SdhD subunits of these isolates were sequenced to reveal an additional mutation on the SdhB subunit gene, H267R, not previously observed in Clarireedia. Cleaved amplified polymorphic sequence (CAPS) and derived CAPS molecular markers were developed to detect five mutations conferring SDHI resistance in Clarireedia isolates and validated using samples from two additional golf courses in Connecticut and Wisconsin experiencing SDHI field failure. This PCR-based molecular detection system will be useful for continued monitoring, assessment, and delay of SDHI resistance in the field.
  • Soil nutrient and nematode community changes in response to hardwood charcoal application
    Emily J. Cole, Allen V. Barker, Omid R. Zandvakili, Amir Sadeghpour, Baoshan Xing, Masoud Hashemi, Elisha Allan-Perkins, Geunhwa Jung
    COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 52 9 917 - 925 2021年 [査読有り]
  • Soil Microbial Communities on Roughs, Fairways, and Putting Greens of Cool-Season Golf Courses
    Elisha Allan-Perkins, Daniel K. Manter, Geunhwa Jung
    Crop Science 59 1753 - 1767 2019年 [査読有り][通常論文]
  • James T. Popko, Hyunkyu Sang, Jaemin Lee, Toshihiko Yamada, Yoichiro Hoshino, Geunhwa Jung
    Plant Disease 102 12 2625 - 2631 2018年12月 [査読有り][通常論文]
  • Dylan Kessler, Hyunkyu Sang, Amanda Bousquet, Jonathan P. Hulvey, Dawlyn Garcia, Siyeon Rhee, Yoichiro Hoshino, Toshihiko Yamada, Geunhwa Jung
    Fungal Genetics and Biology 115 64 - 77 2018年06月01日 [査読有り][通常論文]
     
    Sclerotinia homoeocarpa is the causal organism of dollar spot in turfgrasses and is a multinucleate fungus with a history of resistance to multiple fungicide classes. Heterokaryosis gives rise to the coexistence of genetically distinct nuclei within a cell, which contributes to genotypic and phenotypic plasticity in multinucleate fungi. We demonstrate that field isolates, resistant to either a demethylation inhibitor or methyl benzimidazole carbamate fungicide, can form heterokaryons with resistance to each fungicide and adaptability to serial combinations of different fungicide concentrations. Field isolates and putative heterokaryons were assayed on fungicide-amended media for in vitro sensitivity. Shifts in fungicide sensitivity and microsatellite genotypes indicated that heterokaryons could adapt to changes in fungicide pressure. Presence of both nuclei in heterokaryons was confirmed by detection of a single nucleotide polymorphism in the β-tubulin gene, the presence of microsatellite alleles of both field isolates, and the live-cell imaging of two different fluorescently tagged nuclei using laser scanning confocal microscopy. Nucleic adaptability of heterokaryons to fungicides was strongly supported by the visualization of changes in fluorescently labeled nuclei to fungicide pressure. Results from this study suggest that heterokaryosis is a mechanism by which the pathogen adapts to multiple fungicide pressures in the field.
  • Abundance of bacteria, fungi, and Sclerotinia homoeocarpa in the thatch versus soil of golf courses
    Elisha Allan-Perkins, Daniel Manter, Geunhwa Jung
    Phytobiomes 2 71 - 81 2018年 [査読有り][通常論文]
  • Chlorothalonil Biotransformation by Cytochrome P450 Monooxygenases in Sclerotinia homoeocarpa
    Robert Green, Hyunkyu Sang, Jeongdae Im, Geunhwa Jung
    FEMS Microbiology Letters 365 2018年 [査読有り][通常論文]
  • A Xenobiotic detoxification pathway through transcriptional regulation in filamentous fungi
    Hyunkyu Sang, Jonatha, P. Hulvey, Robert Green, Hao Xu, Jeongdae Im, Taehyun Chang, Geunhwa Jung
    mBio 9 2018年 [査読有り][通常論文]
  • Elisha Allan-Perkins, Daniel K. Manter, Robert Wick, Scott Ebdon, Geunhwa Jung
    APPLIED SOIL ECOLOGY 121 161 - 171 2017年12月 [査読有り][通常論文]
     
    Nematodes are an important component of the golf course ecosystem. Many species provide benefits to turfgrass, while others can cause significant damage. Previous studies on golf courses have focused only on herbivore nematodes, mostly on putting greens. This study aimed to characterize all nematode trophic groups and nematode maturity and ecological indices under different management intensities (depicted by roughs, fairways, and putting greens) of three golf courses representing conventional and organic management types over two seasons in 2013 and 2014. The putting greens on all three golf courses had lower diversity and herbivore (plant-parasitic) index (PPI) values than the other management areas. The relative abundance of herbivores, bacterivores, and structure index (SI) values differed among organic and conventional management. Canonical correspondence and multiple stepwise regression analyses revealed pH, phosphorous, and organic matter were positively related to increased herbivores and negatively related to increased bacterivores. The results of this study can be used to develop alternative management practices aimed at decreasing problematic herbivore populations on putting greens and increasing potentially beneficial bacterivores.
  • 日本と韓国のゴルフ場におけるダラースポット病低減のためのフェアウェイローリングの効果
    Geunhwa Jung, Taehyun Chang, 山田敏彦
    北海道芝草研究会誌 41 16 - 18 2017年07月 [査読無し][通常論文]
  • Elisha Allan-Perkins, Katie Campbell-Nelson, James T. Popko, Hyunkyu Sang, Geunhwa Jung
    CROP SCIENCE 57 S301 - S309 2017年07月 [査読有り][通常論文]
     
    Dollar spot, caused by Sclerotinia homoeocarpa F.T. Bennett, is the most economically important disease of golf course turfgrass in the northern United States. Fungicide resistance, especially to demethylation inhibitor (DMI) fungicides, is common for S. homoeocarpa. Plant growth regulators (PGRs) are commonly applied on golf courses and have a similar chemistry to DMIs. Previous research has suggested multiple resistance among the PGRs flurprimidol and paclobutrazol, the succinase dehydrogenase inhibitor fungicide boscalid, and the DMI propiconazole, with evidence for the involvement of the multidrug efflux transporter gene, ShPDR1. The objective of this research was to investigate if flurprimidol, paclobutrazol, and boscalid select for DMI insensitivity in the field. We tested eight treatments: flurprimidol alone, tank-mixed with propiconazole, and rotated with propiconazole; paclobutrazol alone, tank-mixed with propiconazole, and rotated with propiconazole; propiconazole alone; and boscalid alone. S. homoeocarpa was isolated from infected turfgrass three times per year in 2010 and 2011 following treatment applications. A significant shift in DMI insensitivity was observed from the initial sampling in 2010 to the final sampling in 2011 for all treatments, except the PGRs alone and the untreated control. Both PGRs induced overexpression of ShPDR1, and we confirmed the functional involvement of ShPDR1 in reducing S. homoeocarpa sensitivity to PGRs using the ShPDR1 overexpressing yeast mutant. These results have important implications for managing DMI resistance, further investigating the fungistatic activity of PGRs, and developing new fungicides for S. homoeocarpa.
  • Junli Li, Hyunkyu Sang, Huiyuan Guo, James T. Popko, Lili He, Jason C. White, Om Parkash Dhankher, Geunhwa Jung, Baoshan Xing
    NANOTECHNOLOGY 28 15 2017年04月 [査読有り][通常論文]
     
    Fungicides have extensively been used to effectively combat fungal diseases on a range of plant species, but resistance to multiple active ingredients has developed in pathogens such as Sclerotinia homoeocarpa, the causal agent of dollar spot on cool-season turfgrasses. Recently, ZnO and Ag nanoparticles (NPs) have received increased attention due to their antimicrobial activities. In this study, the NPs' toxicity and mechanisms of action were investigated as alternative antifungal agents against S. homoeocarpa isolates that varied in their resistance to demethylation inhibitor (DMI) fungicides. S. homoeocarpa isolates were treated with ZnO NPs and ZnCl2 (25-400 mu g ml(-1)) and Ag NPs and AgNO3 (5-100 mu g ml(-1)) to test antifungal activity of the NPs and ions. The mycelial growth of S. homoeocarpa isolates regardless of their DMI sensitivity was significantly inhibited on ZnO NPs (>= 200 mu g ml(-1)), Ag NPs (>= 25 mu g ml(-1)), Zn2+ ions (>= 200 mu g ml(-1)), and Ag+ ions (>= 10 mu g ml(-1)) amended media. Expression of stress response genes, glutathione S-transferase (Shgst1) and superoxide dismutase 2 (ShSOD2), was significantly induced in the isolates by exposure to the NPs and ions. In addition, a significant increase in the nucleic acid contents of fungal hyphae, which may be due to stress response, was observed upon treatment with Ag NPs using Raman spectroscopy. We further observed that a zinc transporter (Shzrt1) might play an important role in accumulating ZnO and Ag NPs into the cells of S. homoeocarpa due to overexpression of Shzrt1 significantly induced by ZnO or Ag NPs within 3 h of exposure. Yeast mutants complemented with Shzrt1 became more sensitive to ZnO and Ag NPs as well as Zn2+ and Ag+ ions than the control strain and resulted in increased Zn or Ag content after exposure. This is the first report of involvement of the zinc transporter in the accumulation of Zn and Ag from NP exposure in filamentous plant pathogenic fungi. Understanding the molecular mechanisms of NPs' antifungal activities will be useful in developing effective management strategies to control important pathogenic fungal diseases.
  • Hyunkyu Sang, James T. Popko, Taehyun Chang, Geunhwa Jung
    PHYTOPATHOLOGY 107 2 198 - 207 2017年02月 [査読有り][通常論文]
     
    The dicarboximide fungicide class is commonly used to control Sclerotinia homoeocarpa, the causal agent of dollar spot on turfgrass. Despite frequent occurrences of S. homoeocarpa field resistance to iprodione (dicarboximide active ingredient), the genetic mechanisms of iprodione resistance have not been elucidated. In this study, 15 field isolates (seven suspected dicarboximide resistant, three multidrug resistance (MDR)-like, and five dicarboximide sensitive) were used for sequence comparison of a histidine kinase gene, Shos1, of S. homoeocarpa. The suspected dicarboximide-resistant isolates displayed nonsynonymous polymorphisms in codon 366 (isoleucine to asparagine) in Shos1, while the MDR-like and sensitive isolates did not. Further elucidation of the Shos1 function, using polyethylene glycol mediated protoplast transformation indicated that S. homoeocarpa mutants (Shos1(1366N)) from a sensitive isolate gained resistance to dicarboximides but not phenylpyrrole and polyols. The deletion of Shos1 resulted in higher resistance to dicarboximide and phenylpyrrole and higher sensitivity to polyols than Shos1(1366N). Levels of dicarboximide sensitivity in the sensitive isolate, Shos1(1366N), and Shosl deletion mutants were negatively correlated to values of iprodione-induced expression of ShHog1, the last kinase in the high-osmolarity glycerol pathway. Increased constitutive and induced expression of the ATP-binding cassette multidrug efflux transporter ShPDR1 was observed in six of seven dicarboximide-resistant isolates. In conclusion, S. homoeocarpa field isolates gained dicarboximide resistance through the polymorphism in Shosl and the overexpression of ShPDR1.
  • Draft genome sequences of the turfgrass pathogen Sclerotinia homoeocarpa
    Robert Green, Hyunkyu Sang, Taehyun Chang, Elisha Allan-Perkins, Elsa Petit, Geunhwa Jung
    Genome Announcements 4 2016年 [査読有り][通常論文]
  • Hyunkyu Sang, Jon Hulvey, James T. Popko, John Lopes, Aishwarya Swaminathan, Taehyun Chang, Geunhwa Jung
    MOLECULAR PLANT PATHOLOGY 16 3 251 - 261 2015年04月 [査読有り][通常論文]
     
    Dollar spot, caused by Sclerotinia homoeocarpa, is a prevalent turfgrass disease, and the fungus exhibits widespread fungicide resistance in North America. In a previous study, an ABC-G transporter, ShatrD, was associated with practical field resistance to demethylation inhibitor (DMI) fungicides. Mining of ABC-G transporters, also known as pleiotropic drug resistance (PDR) transporters, from RNA-Seq data gave an assortment of transcripts, several with high sequence similarity to functionally characterized transporters from Botrytis cinerea, and others with closest BLASTX hits from Aspergillus and Monilinia. In addition to ShatrD, another PDR transporter showed significant over-expression in replicated RNA-Seq data, and in a collection of field-resistant isolates, as measured by quantitative polymerase chain reaction. These isolates also showed reduced sensitivity to unrelated fungicide classes. Using a yeast complementation system, we sought to test the hypothesis that this PDR transporter effluxes DMI as well as chemically unrelated fungicides. The transporter (ShPDR1) was cloned into the Gal1 expression vector and transformed into a yeast PDR transporter deletion mutant, AD12345678. Complementation assays indicated that ShPDR1 complemented the mutant in the presence of propiconazole (DMI), iprodione (dicarboximide) and boscalid (SDHI, succinate dehydrogenase inhibitor). Our results indicate that the over-expression of ShPDR1 is correlated with practical field resistance to DMI fungicides and reduced sensitivity to dicarboximide and SDHI fungicides. These findings highlight the potential for the eventual development of a multidrug resistance phenotype in this pathogen. In addition, this study presents a pipeline for the discovery and validation of fungicide resistance genes using de novo next-generation sequencing and molecular biology techniques in an unsequenced plant pathogenic fungus.
  • Loreto Araneda, Sung-Chur Sim, Jin-Joo Bae, Nanda Chakraborty, Joe Curley, Taehyun Chang, Maiko Inoue, Scott Warnke, Geunhwa Jung
    PLoS ONE 8 2013年 [査読有り][通常論文]
  • Jon Hulvey, James T. Popko, Hyunkyu Sang, Andrew Berg, Geunhwa Jung
    APPLIED AND ENVIRONMENTAL MICROBIOLOGY 78 18 6674 - 6682 2012年09月 [査読有り][通常論文]
     
    We investigated genetic factors that govern the reduced propiconazole sensitivity of Sclerotinia homoeocarpa field isolates collected during a 2-year field efficacy study on dollar spot disease of turf in five New England sites. These isolates displayed a >50-fold range of in vitro sensitivity to a sterol demethylation inhibitor (DMI) fungicide, propiconazole, making them ideal for investigations of genetic mechanisms of reduced DMI sensitivity. The CYP51 gene homolog in S. homoeocarpa (ShCYP51B), encoding the enzyme target of DMIs, is likely a minor genetic factor for reduced propiconazole sensitivity, since there were no differences in constitutive relative expression (RE) values and only 2-fold-higher induced RE values for insensitive than for sensitive isolate groups. Next, we mined RNA-Seq transcriptome data for additional genetic factors and found evidence for the overexpression of a homolog of Botrytis cinerea atrD (BcatrD), ShatrD, a known efflux transporter of DMI fungicides. The ShatrD gene showed much higher constitutive and induced RE values for insensitive isolates. Several polymorphisms were found upstream of ShatrD but were not definitively linked to overexpression. The screening of constitutive RE values of ShCYP51B and ShatrD in isolates from two golf courses that exhibited practical field resistance to propiconazole uncovered evidence for significant population-specific overexpression of both genes. However, linear regression demonstrated that the RE of ShatrD displays a more significant relationship with propiconazole sensitivity than that of ShCYP51B. In summary, our results suggest that efflux is a major determinant of the reduced DMI sensitivity of S. homoeocarpa genotypes in New England, which may have implications for the emergence of practical field resistance in this important turfgrass pathogen.
  • James T. Popko, Chang-Ho Ok, Katie Campbell-Nelson, Geunhwa Jung
    PLANT DISEASE 96 4 552 - 561 2012年04月 [査読有り][通常論文]
     
    Dollar spot (Sclerotinia homoeocarpa) is a major turfgrass disease requiring fungicide application to maintain acceptable conditions for golf. A 2-year field experiment was conducted to determine the association between field efficacy of propiconazole and in vitro fungicide sensitivity of isolates from five S. homoeocarpa populations. Four golf courses with prior propiconazole exposure (Hartford Golf Club, Hickory Ridge Country Club, Shuttle Meadow Country Club, and Wintonbury Hills Golf Club), and a baseline site with no prior propiconazole exposure (Joseph Troll Turf Research Facility) were chosen as field sites. Experimental plots at each site received the following treatments at 21-day intervals: untreated, propiconazole (0.44, 0.88, 1.32, and 1.76 kg a.i. ha(-1)), and chlorothalonil (8.18 kg a.i. ha(-1)). S. homoeocarpa isolates were sampled at three time points during 2009 and 2010: initial (directly before fungicide treatment). 7 days after treatment (DAT), and 21 days after the last treatment. Isolates sampled from dollar spot infection centers at 7 DAT (2009 and 2010) were considered to exhibit "practical field resistance". In parallel, S. homoeocarpa isolates from each site were assayed for in vitro sensitivity to propiconazole by determining relative mycelium growth percentages (RMG%) on potato dextrose agar amended with propiconazole at a discriminatory concentration of 0.1 pg a.i. ml(-1). S. homoeocarpa isolates from the four exposed populations displayed significantly higher RMG% values than the baseline population. In general, field efficacy at all propiconazole rates tested was lower at the four locations with prior propiconazole exposure when compared with the baseline population. Increased RMG% values on the propiconazole discriminatory concentration 0.1 pg a.i. ml(-1) were associated with decreased relative control values for all propiconazole rates in 2009 and 2010. Results suggest RMG values above 50% at the propiconazole discriminatory concentration of 0.1 pg a.i. ml(-1) may be a suitable threshold for detection of S. homoeocarpa isolates that cause practical DMI field resistance.
  • Chang-Ho Ok, James T. Popko, Katie Campbell-Nelson, Geunhwa Jung
    PLANT DISEASE 95 1 51 - 56 2011年01月 [査読有り][通常論文]
     
    Dollar spot (caused by Sclerotinia homoeocarpa) is the most economically important turfgrass disease in North America. This disease is primarily controlled by fungicide applications on golf courses; however, fungicide resistance has been confirmed in three of the four systemic fungicide classes commonly used to control dollar spot. The main objective of this study was to evaluate S. homoeocarpa sensitivity to multiple chemical classes and cross-resistance among active ingredients within the same class; in particular, the association between the fungistatic effect of demethylation inhibitors (DMIs) and plant growth regulators (PGRs). Fifty-eight isolates were selected arbitrarily from four locations in the United States and assayed for in vitro sensitivity to six DMI, two dicarboximide, one carboximide, and one benzimidazole fungicide as well as three type II PGRs. A series of concentrations for each active ingredient was used to determine the mean 50% effective concentration (EC(50)) values and correlation coefficients were calculated for all active ingredients. The EC(50) values of all active ingredients from the DMI class were highly correlated (P < 0.0001) to each other as well as to the one dicarboximide (iprodione) and two PGRs (flurprimidol and paclobutrazol). Isolates resistant to thiophanate-methyl had significantly higher EC(50) values than sensitive isolates for all active ingredients assayed except for boscalid. Findings showed that multiple and cross-resistance has developed in S. homoeocarpa and that the two PGRs have a fungistatic effect on this pathogen similar to that of DMI fungicides. The high correlation of in vitro sensitivities among PGRs and DMI fungicides further suggests that PGRs may contribute to the selection of DMI-resistant isolates or facilitate decreased sensitivity to DMI fungicides in the field.
  • Young-Ki Jo, Seog Won Chang, Michael Boehm, Geunhwa Jung
    PHYTOPATHOLOGY 98 12 1297 - 1304 2008年12月 [査読有り][通常論文]
     
    Dollar spot, caused by Sclerotinia homoeocarpa, is the most prevalent and economically important turfgrass disease in North America. Increasing levels of fungicide resistance, Coupled with tightening environmental scrutiny of existing fungicides, has left fewer options for managing dollar spot. More knowledge about S. homoeocarpa populations is needed to improve dollar spot management strategies, especially with respect to minimizing the development of fungicide resistance. Population diversity of S. homoeocarpa was examined using inter-simple sequence repeat markers and vegetative compatibility assays. Two subgroups Were found in S. homoeocarpa field populations on both fairway and Putting green turfgrass at a research field in Wisconsin. These subgroups were genetically different, vegetatively incompatible, and had different fungicide sensitivities. The frequency of the two genetic Subgroups differed significantly between the fairway and putting green, but was uniform within the fairway or within the green. Population dynamics of S. homoeocarpa in response to two systemic fungicides (thiophanate-methyl and propiconazole) were assessed based oil in vitro fungicide sensitivity. Dynamics of S. homoeocarpa populations depended on the presence of fungicide-resistant isolates in the initial populations before fungicide applications and changed rapidly after fungicide applications. Shifting of the population toward propiconazole resistance was gradual, whereas thiophanatemethyl resistance developed rapidly in the population. In conclusion, field populations of S. homoeocarpa containing genetically distinct. vegetatively incompatible groups were different on turfgrass that was managed differently, and they were changed rapidly after exposure to fungicides.

書籍

  • Fungicide Resistance in North America, Second Edition, APS PRESS
    Elisha Allan, Jon Hulvey, James Popko, Jr, Nathaniel Mitkowski, Joe Vargas, Geunhwa Jung (担当:共著)
    APS Press 2019年08月

講演・口頭発表等

  • Dollar spot management: rolling, really?  [招待講演]
    Geunhwa Jung
    the 6th ETS Field Days 2019 in Padova, Italy 2019年05月 口頭発表(招待・特別)

共同研究・競争的資金等の研究課題

  • Sclerotinia homoeocarpa epidemiology and resistance development as measured through improved molecular detection techniques
    United States Golf Association:
    研究期間 : 2018年03月 -2021年03月 
    代表者 : Paul Koch, JoAnne Crouch, Bruce Clarke, James Murphy, Geunhwa Jung


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