scholarly journals Comparisons of Ectomycorrhizal Colonization of Transgenic American Chestnut with Those of the Wild Type, a Conventionally Bred Hybrid, and Related Fagaceae Species

2014 ◽  
Vol 81 (1) ◽  
pp. 100-108 ◽  
Author(s):  
Katherine M. D'Amico ◽  
Thomas R. Horton ◽  
Charles A. Maynard ◽  
Stephen V. Stehman ◽  
Allison D. Oakes ◽  
...  
Keyword(s):  
Cryphonectria Parasitica ◽  
Oxalate Oxidase ◽  
Fungal Species ◽  
American Chestnut ◽  
Fungal Colonization ◽  
Wild Type ◽  
Root Tips ◽  
Oxidase Gene ◽  
Content Type ◽  
Ectomycorrhizal Colonization

ABSTRACTAmerican chestnut (Castanea dentata[Marsh.] Borkh.) dominated the eastern forests of North America, serving as a keystone species both ecologically and economically until the introduction of the chestnut blight,Cryphonectria parasitica, functionally eradicated the species. Restoration efforts include genetic transformation utilizing genes such as oxalate oxidase to produce potentially blight-resistant chestnut trees that could be released back into the native range. However, before such a release can be undertaken, it is necessary to assess nontarget impacts. Since oxalate oxidase is meant to combat a fungal pathogen, we are particularly interested in potential impacts of this transgene on beneficial fungi. This study compares ectomycorrhizal fungal colonization on a transgenic American chestnut clone expressing enhanced blight resistance to a wild-type American chestnut, a conventionally bred American-Chinese hybrid chestnut, and other Fagaceae species. A greenhouse bioassay used soil from two field sites with different soil types and land use histories. The number of colonized root tips was counted, and fungal species were identified using morphology, restriction fragment length polymorphism (RFLP), and DNA sequencing. Results showed that total ectomycorrhizal colonization varied more by soil type than by tree species. Individual fungal species varied in their colonization rates, but there were no significant differences between colonization on transgenic and wild-type chestnuts. This study shows that the oxalate oxidase gene can increase resistance againstCryphonectria parasiticawithout changing the colonization rate for ectomycorrhizal species. These findings will be crucial for a potential deregulation of blight-resistant American chestnuts containing the oxalate oxidase gene.

scholarly journals First Report of Ectomycorrhizal Fungus, Laccaria ochropurpurea, Associated with Castanea dentata (American Chestnut) Roots in a Mixed-Species Plantation

2019 ◽  
Vol 20 (3) ◽  
pp. 140-141
Author(s):  
Morgan V. Ritzi ◽  
Stephen D. Russell ◽  
M. Catherine Aime ◽  
Gordon G. McNickle
Keyword(s):  
Cryphonectria Parasitica ◽  
Ectomycorrhizal Fungus ◽  
Castanea Dentata ◽  
American Chestnut ◽  
Fungal Colonization ◽  
Root Tips ◽  
Mixed Species ◽  
Plant Host ◽  
Mutualistic Association ◽  
Direct Confirmation

American chestnut (Castanea dentata) is critically endangered by chestnut blight caused by Cryphonectria parasitica. Beneficial interactions with mutualistic ectomycorrhizae sometimes confer resistance to pathogens; however, little is known about the mycorrhizal partners of American chestnut. Basidiocarps of Laccaria ochropurpurea were observed in a 10-year-old American chestnut plantation. The identity of the species was confirmed utilizing the nuclear ribosomal internal transcribed spacer. In spring 2018, root fragments were excised from beneath three American chestnut trees in three separate plots where basidiocarps were observed. Root tips with evidence of mycorrhizal fungal colonization were pooled, extracted, and sequenced to confirm both the plant host and mycorrhizal associates. To our knowledge, this is the first direct confirmation of American chestnut roots associated with L. ochropurpurea. We suggest further studies to investigate whether this association is common, whether it confers any disease resistance, and if this mutualistic association could be employed in restoration efforts of the American chestnut.

scholarly journals Agrobacterium-mediated co-transformation of American Chestnut (Castanea dentata) somatic embryos with a wheat oxalate oxidase gene

2011 ◽  
Vol 5 (S7) ◽  
Author(s):  
Bo Zhang ◽  
Andrew Newhouse ◽  
Linda McGuigan ◽  
Charles Maynard ◽  
William Powell
Keyword(s):  
Somatic Embryos ◽  
Oxalate Oxidase ◽  
Castanea Dentata ◽  
American Chestnut ◽  
Oxidase Gene

scholarly journals Mutual Exclusion between Fungal Species of the Fusarium Head Blight Complex in a Wheat Spike

2015 ◽  
Vol 81 (14) ◽  
pp. 4682-4689 ◽  
Author(s):  
Dorothée Siou ◽  
Sandrine Gélisse ◽  
Valérie Laval ◽  
Frédéric Suffert ◽  
Christian Lannou
Keyword(s):  
Mutual Exclusion ◽  
Field Studies ◽  
Fungal Species ◽  
Microdochium Nivale ◽  
Fungal Colonization ◽  
Head Blight ◽  
Classical Analysis ◽  
Content Type ◽  
Single Spike ◽  
Wheat Spike

ABSTRACTFusariumhead blight (FHB) is one of the most damaging diseases of wheat. FHB is caused by a species complex that includes two genera of Ascomycetes:MicrodochiumandFusarium. Fusarium graminearum,Fusariumculmorum,Fusariumpoae, andMicrodochium nivaleare among the most common FHB species in Europe and were chosen for these experiments. Field studies and surveys show that two or more species often coexist within the same field or grain sample. In this study, we investigated the competitiveness of isolates of different species against isolates ofF. graminearumat the scale of a single spike. By performing point inoculations of a single floret, we ensured that each species was able to establish independent infections and competed for spike colonization only. The fungal colonization was assessed in each spike by quantitative PCR. After establishing that the spike colonization was mainly downwards, we compared the relative colonization of each species in coinoculations. Classical analysis of variance suggested a competitive interaction but remained partly inconclusive because of a large between-spike variance. Further data exploration revealed a clear exclusion of one of the competing species and the complete absence of coexistence at the spike level.

scholarly journals Micafungin Breakthrough Fungemia in Patients with Hematological Disorders

2018 ◽  
Vol 62 (5) ◽  
Author(s):  
Muneyoshi Kimura ◽  
Hideki Araoka ◽  
Hisashi Yamamoto ◽  
Shigeki Nakamura ◽  
Minoru Nagi ◽  
...  
Keyword(s):  
Candida Parapsilosis ◽  
Drug Susceptibility ◽  
Fungal Species ◽  
Limited Data ◽  
Wild Type ◽  
Content Type ◽  
Hematological Disorders ◽  
Crude Mortality Rate ◽  
Crude Mortality ◽  
High Range

ABSTRACT Limited data are available on micafungin breakthrough fungemia (MBF), fungemia that develops on administration of micafungin, in patients with hematological disorders. We reviewed medical and microbiological records of patients with hematological disorders who developed MBF between January 2008 and June 2015. A total of 39 patients with MBF were identified, and Candida (30 strains) and non- Candida (9 strains) fungal species were recognized as causative strains. Among 35 stored strains, Candida parapsilosis (14 strains), Trichosporon asahii (7 strains), Candida glabrata (5 strains), and other fungal species (9 strains) were identified by sequencing. Neutropenia was identified as an independent predictor of non- Candida fungemia ( P = 0.023). T. asahii was the most common causative strain (7/19) during neutropenia. The 14-day crude mortality rate of patients treated with early micafungin change (EMC) to other antifungal agents was lower than that of the patients not treated with EMC (14% versus 43%, P = 0.044). Most of the stored causative Candida strains were susceptible (80%) or showed wild-type susceptibility (72%) to micafungin. The MICs of voriconazole for T. asahii were low (range, 0.015 to 0.12 μg/ml), whereas the MICs of amphotericin B for T. asahii were high (range, 2 to 4 μg/ml). MBF caused by non- Candida fungus should be considered, especially in patients with neutropenia. EMC could improve early mortality. Based on epidemiology and drug susceptibility profiling, empirical voriconazole-containing therapy might be suitable for treating MBF during neutropenia to cover for T. asahii .

scholarly journals A threshold level of oxalate oxidase transgene expression reduces Cryphonectria parasitica-induced necrosis in a transgenic American chestnut (Castanea dentata) leaf bioassay

2013 ◽  
Vol 22 (5) ◽  
pp. 973-982 ◽  
Author(s):  
Bo Zhang ◽  
Allison D. Oakes ◽  
Andrew E. Newhouse ◽  
Kathleen M. Baier ◽  
Charles A. Maynard ◽  
...  
Keyword(s):  
Transgene Expression ◽  
Threshold Level ◽  
Cryphonectria Parasitica ◽  
Oxalate Oxidase ◽  
Castanea Dentata ◽  
American Chestnut

scholarly journals Major impacts on the primary metabolism of the plant pathogen Cryphonectria parasitica by the virulence-attenuating virus CHV1-EP713

Microbiology ◽  
2009 ◽  
Vol 155 (12) ◽  
pp. 3913-3921 ◽  
Author(s):  
Angus L. Dawe ◽  
Wayne A. Van Voorhies ◽  
Tannia A. Lau ◽  
Alexander V. Ulanov ◽  
Zhong Li
Keyword(s):  
Metabolic Rate ◽  
Carbohydrate Metabolism ◽  
Cryphonectria Parasitica ◽  
Fungal Species ◽  
Primary Metabolism ◽  
Wild Type ◽  
Primary Metabolites ◽  
Antiviral Responses ◽  
Chestnut Blight Fungus ◽  
The Family

Cryphonectria parasitica, the chestnut blight fungus, can be infected by virulence-attenuating mycoviruses of the family Hypoviridae. Previous studies have led to the hypothesis that the hypovirus-infected phenotype is partly due to metabolic changes induced by the viral infection. To investigate this, we measured the metabolic rate and respiration of C. parasitica colonies grown on solid medium. These experiments supported historical observations of other fungal species done in liquid cultures that the metabolic rate steadily declines with age and differentiation of the mycelium. Hypovirus infection increased metabolic rate in the youngest mycelium, but a subsequent decline was also observed as the mycelium aged. By measuring both CO2 production and O2 consumption, we also observed that changes occur in carbohydrate metabolism as a result of ageing in both infected and uninfected mycelium. Mycelium on the periphery of the colony exploited fermentation pathways extensively, before transitioning to aerobic carbohydrate metabolism and finally lipid metabolism in the interior regions, despite abundant remaining glucose. However, the hypovirus affected the extent of these changes, with infected mycelium apparently unable to utilize lipid-related metabolic pathways, leading to an increased depletion of glucose. Finally, we used metabolic profifiling to determine the changes in accumulation of primary metabolites in wild-type and hypovirus-infected mycelium and found that approximately one-third of the 164 detected metabolites were affected. These results are consistent with those expected from the physiological measurements, with significant alterations noted for compounds related to lipid and carbohydrate metabolism. Additionally, we observed an increase in the accumulation of the polyamine spermidine in the presence of hypovirus. Polyamines have been implicated in antiviral responses of mammalian systems; therefore this may suggest a novel antiviral response mechanism in fungi.

scholarly journals Mutations in fbiD (Rv2983) as a Novel Determinant of Resistance to Pretomanid and Delamanid in Mycobacterium tuberculosis

2020 ◽  
Vol 65 (1) ◽  
pp. e01948-20
Author(s):  
Dalin Rifat ◽  
Si-Yang Li ◽  
Thomas Ioerger ◽  
Keshav Shah ◽  
Jean-Philippe Lanoix ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Clinical Evidence ◽  
Clinical Samples ◽  
Loss Of Function ◽  
Wild Type ◽  
Content Type ◽  
Solid Media ◽  
High Level ◽  
Level Resistance

ABSTRACTThe nitroimidazole prodrugs delamanid and pretomanid comprise one of only two new antimicrobial classes approved to treat tuberculosis (TB) in 50 years. Prior in vitro studies suggest a relatively low barrier to nitroimidazole resistance in Mycobacterium tuberculosis, but clinical evidence is limited to date. We selected pretomanid-resistant M. tuberculosis mutants in two mouse models of TB using a range of pretomanid doses. The frequency of spontaneous resistance was approximately 10−5 CFU. Whole-genome sequencing of 161 resistant isolates from 47 mice revealed 99 unique mutations, of which 91% occurred in 1 of 5 genes previously associated with nitroimidazole activation and resistance, namely, fbiC (56%), fbiA (15%), ddn (12%), fgd (4%), and fbiB (4%). Nearly all mutations were unique to a single mouse and not previously identified. The remaining 9% of resistant mutants harbored mutations in Rv2983 (fbiD), a gene not previously associated with nitroimidazole resistance but recently shown to be a guanylyltransferase necessary for cofactor F420 synthesis. Most mutants exhibited high-level resistance to pretomanid and delamanid, although Rv2983 and fbiB mutants exhibited high-level pretomanid resistance but relatively small changes in delamanid susceptibility. Complementing an Rv2983 mutant with wild-type Rv2983 restored susceptibility to pretomanid and delamanid. By quantifying intracellular F420 and its precursor Fo in overexpressing and loss-of-function mutants, we provide further evidence that Rv2983 is necessary for F420 biosynthesis. Finally, Rv2983 mutants and other F420H2-deficient mutants displayed hypersusceptibility to some antibiotics and to concentrations of malachite green found in solid media used to isolate and propagate mycobacteria from clinical samples.

scholarly journals The Serratia marcescens Siderophore Serratiochelin Is Necessary for Full Virulence during Bloodstream Infection

2020 ◽  
Vol 88 (8) ◽  
Author(s):  
Danelle R. Weakland ◽  
Sara N. Smith ◽  
Bailey Bell ◽  
Ashootosh Tripathi ◽  
Harry L. T. Mobley
Keyword(s):  
Serratia Marcescens ◽  
Bloodstream Infection ◽  
Iron Acquisition ◽  
Gene Clusters ◽  
Clinical Isolates ◽  
Wild Type ◽  
Serratia Plymuthica ◽  
Content Type ◽  
Cas Assay ◽  
Essential Nutrient

ABSTRACT Serratia marcescens is a bacterium frequently found in the environment, but over the last several decades it has evolved into a concerning clinical pathogen, causing fatal bacteremia. To establish such infections, pathogens require specific nutrients; one very limited but essential nutrient is iron. We sought to characterize the iron acquisition systems in S. marcescens isolate UMH9, which was recovered from a clinical bloodstream infection. Using RNA sequencing (RNA-seq), we identified two predicted siderophore gene clusters (cbs and sch) that were regulated by iron. Mutants were constructed to delete each iron acquisition locus individually and in conjunction, generating both single and double mutants for the putative siderophore systems. Mutants lacking the sch gene cluster lost their iron-chelating ability as quantified by the chrome azurol S (CAS) assay, whereas the cbs mutant retained wild-type activity. Mass spectrometry-based analysis identified the chelating siderophore to be serratiochelin, a siderophore previously identified in Serratia plymuthica. Serratiochelin-producing mutants also displayed a decreased growth rate under iron-limited conditions created by dipyridyl added to LB medium. Additionally, mutants lacking serratiochelin were significantly outcompeted during cochallenge with wild-type UMH9 in the kidneys and spleen after inoculation via the tail vein in a bacteremia mouse model. This result was further confirmed by an independent challenge, suggesting that serratiochelin is required for full S. marcescens pathogenesis in the bloodstream. Nine other clinical isolates have at least 90% protein identity to the UMH9 serratiochelin system; therefore, our results are broadly applicable to emerging clinical isolates of S. marcescens causing bacteremia.

scholarly journals Cytochrome P450 Monooxygenase-Mediated Metabolic Utilization of Benzo[a]Pyrene by Aspergillus Species

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Erin M. Ostrem Loss ◽  
Mi-Kyung Lee ◽  
Ming-Yueh Wu ◽  
Julia Martien ◽  
Wanping Chen ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Environmental Pollutants ◽  
Energy Generation ◽  
Fungal Species ◽  
Metabolic Changes ◽  
Cytochrome P450 Monooxygenase ◽  
Cellular Growth ◽  
P450 Monooxygenase ◽  
Content Type ◽  
Fundamental Knowledge

ABSTRACT Soil-dwelling fungal species possess the versatile metabolic capability to degrade complex organic compounds that are toxic to humans, yet the mechanisms they employ remain largely unknown. Benzo[a]pyrene (BaP) is a pervasive carcinogenic contaminant, posing a significant concern for human health. Here, we report that several Aspergillus species are capable of degrading BaP. Exposing Aspergillus nidulans cells to BaP results in transcriptomic and metabolic changes associated with cellular growth and energy generation, implying that the fungus utilizes BaP as a growth substrate. Importantly, we identify and characterize the conserved bapA gene encoding a cytochrome P450 monooxygenase that is necessary for the metabolic utilization of BaP in Aspergillus. We further demonstrate that the fungal NF-κB-type velvet regulators VeA and VelB are required for proper expression of bapA in response to nutrient limitation and BaP degradation in A. nidulans. Our study illuminates fundamental knowledge of fungal BaP metabolism and provides novel insights into enhancing bioremediation potential. IMPORTANCE We are increasingly exposed to environmental pollutants, including the carcinogen benzo[a]pyrene (BaP), which has prompted extensive research into human metabolism of toxicants. However, little is known about metabolic mechanisms employed by fungi that are able to use some toxic pollutants as the substrates for growth, leaving innocuous by-products. This study systemically demonstrates that a common soil-dwelling fungus is able to use benzo[a]pyrene as food, which results in expression and metabolic changes associated with growth and energy generation. Importantly, this study reveals key components of the metabolic utilization of BaP, notably a cytochrome P450 monooxygenase and the fungal NF-κB-type transcriptional regulators. Our study advances fundamental knowledge of fungal BaP metabolism and provides novel insight into designing and implementing enhanced bioremediation strategies.

scholarly journals MetR-Regulated Vibrio cholerae Metabolism Is Required for Virulence

mBio ◽  
2012 ◽  
Vol 3 (5) ◽  
Author(s):  
Ryan W. Bogard ◽  
Bryan W. Davies ◽  
John J. Mekalanos
Keyword(s):  
Amino Acid ◽  
Vibrio Cholerae ◽  
Virulence Factor ◽  
Current Knowledge ◽  
Intestinal Colonization ◽  
Wild Type ◽  
Pathogenic Potential ◽  
Content Type ◽  
Mouse Intestine

ABSTRACTLysR-type transcriptional regulators (LTTRs) are the largest, most diverse family of prokaryotic transcription factors, with regulatory roles spanning metabolism, cell growth and division, and pathogenesis. Using a sequence-defined transposon mutant library, we screened a panel ofV. choleraeEl Tor mutants to identify LTTRs required for host intestinal colonization. Surprisingly, out of 38 LTTRs, only one severely affected intestinal colonization in the suckling mouse model of cholera: the methionine metabolism regulator, MetR. Genetic analysis of genes influenced by MetR revealed thatglyA1andmetJwere also required for intestinal colonization. Chromatin immunoprecipitation of MetR and quantitative reverse transcription-PCR (qRT-PCR) confirmed interaction with and regulation ofglyA1, indicating that misregulation ofglyA1is likely responsible for the colonization defect observed in themetRmutant. TheglyA1mutant was auxotrophic for glycine but exhibited wild-type trimethoprim sensitivity, making folate deficiency an unlikely cause of its colonization defect. MetJ regulatory mutants are not auxotrophic but are likely altered in the regulation of amino acid-biosynthetic pathways, including those for methionine, glycine, and serine, and this misregulation likely explains its colonization defect. However, mutants defective in methionine, serine, and cysteine biosynthesis exhibited wild-type virulence, suggesting that these amino acids can be scavenged in vivo. Taken together, our results suggest that glycine biosynthesis may be required to alleviate an in vivo nutritional restriction in the mouse intestine; however, additional roles for glycine may exist. Irrespective of the precise nature of this requirement, this study illustrates the importance of pathogen metabolism, and the regulation thereof, as a virulence factor.IMPORTANCEVibrio choleraecontinues to be a severe cause of morbidity and mortality in developing countries. Identification ofV. choleraefactors critical to disease progression offers the potential to develop or improve upon therapeutics and prevention strategies. To increase the efficiency of virulence factor discovery, we employed a regulator-centric approach to multiplex our in vivo screening capabilities and allow whole regulons inV. choleraeto be interrogated for pathogenic potential. We identified MetR as a new virulence regulator and serine hydroxymethyltransferase GlyA1 as a new MetR-regulated virulence factor, both required byV. choleraeto colonize the infant mouse intestine. Bacterial metabolism is a prerequisite to virulence, and current knowledge of in vivo metabolism of pathogens is limited. Here, we expand the known role of amino acid metabolism and regulation in virulence and offer new insights into the in vivo metabolic requirements ofV. choleraewithin the mouse intestine.

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