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Janusz J Zwiazek - One of the best experts on this subject based on the ideXlab platform.
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effects of ph on nacl tolerance of american elm Ulmus Americana seedlings inoculated with hebeloma crustuliniforme and laccaria bicolor
Acta Physiologiae Plantarum, 2009Co-Authors: Monica Calvopolanco, Melanie D Jones, Janusz J ZwiazekAbstract:In the present study, we investigated the effects of pH treatments on NaCl tolerance in mycorrhizal and non-mycorrhizal American elm. American elm (Ulmus Americana) seedlings were inoculated with Hebeloma crustuliniforme, Laccaria bicolor or with both mycorrhizal fungi and subsequently subjected to different pH solutions (pH 3, 6 and 9) containing 0 mM (control) and 60 mM NaCl for 4 weeks. Inoculation with the mycorrhizal fungi did not have a large effect on seedling dry weights when the pH and NaCl treatments were considered independently. However, when the inoculated seedlings were treated with 60 mM NaCl at pH 3 or 6, shoot to root ratios and root hydraulic conductivity were higher compared with non-inoculated plants, likely reflecting changes in seedling water flow properties. At pH 6, transpiration rates were about twofold lower in non-inoculated plants treated with NaCl compared with non-treated controls. For NaCl-treated H. crustuliniforme- and L. bicolor-inoculated plants, the greatest reduction of transpiration rates was at pH 9. Treatment with 60 mM NaCl reduced leaf chlorophyll concentrations more in non-inoculated compared with inoculated plants, with the greatest, twofold, decrease occurring at pH 6. At pH 3, root Na concentrations were higher in inoculated than non-inoculated seedlings; however, there was no effect of inoculation on root Na concentrations at pH 6 and 9. Contrary to the roots, the leaves of inoculated plants had lower Na concentrations at pH 6 and 9, but not at pH 3. The results point to an interaction between ECM fungi and root zone pH for salt tolerance of American elm.
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responses of ectomycorrhizal american elm Ulmus Americana seedlings to salinity and soil compaction
Plant and Soil, 2008Co-Authors: Monica Calvo Polanco, Janusz J Zwiazek, Mihaela C VoicuAbstract:American elm (Ulmus Americana) seedlings were either non-inoculated or inoculated with Hebeloma crustuliniforme, Laccaria bicolor and a mixture of the two fungi to study the effects of ectomycorrhizal associations on seedling responses to soil compaction and salinity. The seedlings were grown in the greenhouse in pots containing non-compacted (0.4 g cm−3 bulk density) and compacted (0.6 g cm−3 bulk density) soil and subjected to 60 mM NaCl or 0 mM NaCl (control) treatments for 3 weeks. All three fungal inocula had similar effects on the responses of elm seedlings to soil compaction and salt treatment. In non-compacted soil, ectomycorrhizal fungi reduced plant dry weights, root hydraulic conductance, but did not affect leaf hydraulic conductance and net photosynthesis. When treated with 60 mM NaCl, ectomycorrhizal seedlings had several-fold lower leaf concentrations of Na+ compared with the non-inoculated plants. Soil compaction reduced Na+ leaf concentrations in non-ectomycorrhizal plants and decreased dry weights, gas exchange and root hydraulic conductance. However, in ectomycorrhizal plants, soil compaction had little effect on the leaf Na+ concentrations and on other measured growth and physiological parameters. Our results demonstrated that ECM associations could be highly beneficial to plants growing in sites with compacted soil such as urban areas.
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ectomycorrhizas increase apoplastic water transport and root hydraulic conductivity in Ulmus Americana seedlings
New Phytologist, 2002Co-Authors: T M Muhsin, Janusz J ZwiazekAbstract:Summary • The extent to which water channel transport is responsible for the observed increases in root water flow of ectomycorrhizal plants is reported here. • To examine the contribution of water channel transport to root hydraulic conductance, temperatures in the range 4–20°C and mercuric chloride (HgCl2) were used to study the kinetics of water transport in ectomycorrhizal and nonmycorrhizal roots of American elm (Ulmus Americana) seedlings. • Hydraulic conductance declined with decreasing temperatures in both mycorrhizal and nonmycorrhizal seedlings. However, hydraulic conductance and conductivity were higher in the mycorrhizal than the nonmycorrhizal roots at all temperatures studied. Mercuric chloride had a relatively greater impact on root hydraulic conductance in nonmycorrhizal than mycorrhizal roots and activation energy for root hydraulic conductance was significantly higher in mycorrhizal than nonmycorrhizal plants. • The results suggest that ectomycorrhizal hyphae increase hydraulic conductance of roots by decreasing water flow resistance of the apoplast rather than by water channel-mediated transport. The high rates of hydraulic conductance at low root temperatures might be important to plants growing in cold soils and under other challenging environmental conditions that inhibit metabolism and limit water transport.
Cristina Rosa - One of the best experts on this subject based on the ideXlab platform.
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First Report of ‘Candidatus Phytoplasma trifolii’-Related Strain of 16SrVI-A Phytoplasma Subgroup, Associated with Elm Yellows Disease in American Elm (Ulmus Americana L.) in Ohio, U.S.A
Plant Disease, 2017Co-Authors: Charles E. Flower, James M Slavicek, Nancy Hayes-plazolles, Cristina RosaAbstract:During the investigation of the sudden and early onset of yellowing and mortality of American elm (Ulmus Americana L.) trees at the USDA Forest Service Northern Research Station in Delaware, OH, a phytoplasma of the clover proliferation group (16SrVI) was detected as the putative causal agent of the disease outbreak.
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first report of candidatus phytoplasma trifolii related strain of 16srvi a phytoplasma subgroup associated with elm yellows disease in american elm Ulmus Americana l in ohio u s a
Plant Disease, 2017Co-Authors: Charles E. Flower, James M Slavicek, Nancy Hayesplazolles, Cristina RosaAbstract:During the investigation of the sudden and early onset of yellowing, followed by mortality of American elm (Ulmus Americana L.) trees at the USDA Forest Service Northern Research Station in Delaware, Ohio, a phytoplasma of the clover proliferation group (16SrVI) was detected as the putative causal agent of the disease outbreak. Onset of symptoms was rapid and widespread, occurring in late July 2016 and affecting ∼60 trees across two elm research plantations. Symptoms included a general yellowing of individual tree canopies, epinasty of foliage throughout the canopy, phloem discoloration, and on a subset of trees, a strong odor of methyl salicylate (observed in phloem tissue extracted from the lower stem). Similar symptoms in elms have been attributed to the classic elm yellows ‘Candidatus Phytoplasma ulmi’ (16SrV-A) (Lee et al. 2004) and the Illinois elm yellows phytoplasma (16SrVI-C) (Jacobs et al. 2003). In July 2016, samples were collected from 12 symptomatic and 8 asymptomatic American elm trees. DNA from the leaf midrib and branch phloem was isolated and analyzed for phytoplasma via seminested polymerase chain reactions (PCR). PCRs were first primed by phytoplasma universal primer pair P5/P7 (Jomantiene et al. 1998), followed by P7 and the reverse complement of the universal phytoplasma primer R16R2 for amplification of the phytoplasma 16S-23 ribosomal (r) DNA (16S-23 rRNA gene) sequences as per Gundersen and Lee (1996). The predicted band size of the second PCR product is 487 base pair (bp). The product bands were isolated, purified, and sequenced using primer P7. Sequencing results of the PCR products indicated that nine of the symptomatic and one of the asymptomatic American elm trees tested were infected by a phytoplasma. A BLAST search of the DNA sequences indicated high similarities to members of the ‘Ca. P. trifolii’ group 16SrVI-A. The sequences of all 10 phytoplasma-infected trees were identical to each other. To further confirm that a strain of ‘Ca. P. trifolii’ was infecting the elms, a PCR product was cloned and sequenced. The 1,557 bp band was the product of primers P1a/P7, followed by PCR primers designed from the sequence of ‘Ca. P. trifolii’. This band was cloned into the pMiniT 2.0 vector. Plasmid sequencing used standard sequencing primers (SP6 and T7 promoters), the primers included with the vector, and finally, custom designed phytoplasma primers that eliminate other bacterial DNA from getting amplified. The entire plasmid clone was sequenced in both directions with four to six times of coverage per base. Determination of the phytoplasma classification group was based on the nucleotide sequence within the phytoplasma universal primers F2n/R2 PCR fragment within the 16Sr gene. Using iPhyClassifier, the online tool for phytoplasma classification and taxonomic assignment (https://plantpathology.ba.ars.usda.gov/cgi-bin/resource/iphyclassifier.cgi), the sequence similarity between the Delaware elm phytoplasma and ‘Ca. P. trifolii’ (GenBank accession no. AB279597.1) is 99.9% in the 16Sr region, which places the Delaware elm phytoplasma in the 16SrVI-A group. The sequence of the plasmid was deposited in GenBank under accession number MF385584. Elm decline and yellows diseases in North America have been associated with the Illinois elm yellows phytoplasma (16SrVI-C, GenBank accession no. AF268893.1) (Jacobs et al. 2003), ‘Ca. Phytoplasma ulmi’ (16SrV-A) (Lee et al. 2004), and phytoplasma in the aster yellows group (16SrI-C) (Lee et al. 1995).
Praveen K Saxena - One of the best experts on this subject based on the ideXlab platform.
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protoplast to plant regeneration of american elm Ulmus Americana
Protoplasma, 2015Co-Authors: Andrew Maxwell Phineas Jones, Mukund R Shukla, G C G Biswas, Praveen K SaxenaAbstract:This study describes a protocol for regeneration of plants from cell suspension-derived protoplasts of American elm (Ulmus Americana). Efficient protoplast isolation was achieved from a two-phase culture system through the incorporation of 100 μM 2-aminoindan-2-phosphonic acid, with a yield of approximately 2 × 106 protoplasts/ml packed cell volume. Isolated protoplasts failed to survive in liquid or alginate bead culture systems but initiated and continued to divide when embedded in low melting point agarose beads. Protoplast-derived callus proliferated and differentiated into shoot buds in response to 10 or 20 μM thidiazuron. Differentiated buds elongated and continued to proliferate on elm shoot medium supplemented with 3.0 μM GA3. The protoplast-derived shoots rooted and acclimatized to greenhouse conditions and continued to grow. This system provides the first protoplast-to-plant regeneration system for American elm and provides a framework for the development of protoplast fusion or genome editing technologies.
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inhibition of phenylpropanoid biosynthesis increases cell wall digestibility protoplast isolation and facilitates sustained cell division in american elm Ulmus Americana
BMC Plant Biology, 2012Co-Authors: Maxwell A P Jones, Mukund R Shukla, Abhishek Chattopadhyay, Praveen K SaxenaAbstract:Background Protoplast technologies offer unique opportunities for fundamental research and to develop novel germplasm through somatic hybridization, organelle transfer, protoclonal variation, and direct insertion of DNA. Applying protoplast technologies to develop Dutch elm disease resistant American elms (Ulmus Americana L.) was proposed over 30 years ago, but has not been achieved. A primary factor restricting protoplast technology to American elm is the resistance of the cell walls to enzymatic degradation and a long lag phase prior to cell wall re-synthesis and cell division.
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in vitro conservation of american elm Ulmus Americana potential role of auxin metabolism in sustained plant proliferation
Canadian Journal of Forest Research, 2012Co-Authors: Mukund R Shukla, Maxwell A P Jones, Alan J Sullivan, Susan Gosling, Praveen K SaxenaAbstract:An efficient procedure for the conservation of mature American elm (Ulmus Americana L.) trees that have survived the epidemics of Dutch elm disease and are potential sources of disease resistance i...
Charles E. Flower - One of the best experts on this subject based on the ideXlab platform.
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the complete chloroplast genome sequence of american elm Ulmus Americana and comparative genomics of related species
bioRxiv, 2020Co-Authors: Aziz Ebrahimi, Cornelia C Pinchot, James M Slavicek, Charles E. Flower, Jennifer D Antonides, Keith WoesteAbstract:American elm, Ulmus Americana L., was cultivated widely in USA and Canada as a landscape tree, but the genome of this important species is poorly characterized. For the first time, we describe the sequencing and assembly of the chloroplast genomes of two American elm genotypes (RV16 and Am57845). The complete chloroplast genome of U. Americana ranged from 158,935-158,993 bp. The genome contains 127 genes, including 85 protein-coding genes, 34 tRNA genes and 8 rRNA genes. Between the two American elm chloroplasts we sequenced, we identified 240 sequence variants (SNPs and indels). To evaluate the phylogeny of American elm, we compared the chloroplast genomes of two American elms along with seven Asian elm species and twelve other chloroplast genomes available through the NCBI database. As expected, Ulmus was closely related to Morus and Cannabis, as all three genera are assigned to the Urticales. Comparison of American elm with Asian elms revealed that trnH was absent from the chloroplast of American elm but not most Asian elms; conversely, petB, petD, psbL, trnK, and rps16 are present in the American elm but absent from all Asian elms. The complete chloroplast genome of U. Americana will provide useful genetic resources for characterizing the genetic diversity of U. Americana and potentially help to conserve natural populations of American elm. Key words: Phylogeny; whole chloroplast genome; conservation genetics; comparative genomics; American elm
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First Report of ‘Candidatus Phytoplasma trifolii’-Related Strain of 16SrVI-A Phytoplasma Subgroup, Associated with Elm Yellows Disease in American Elm (Ulmus Americana L.) in Ohio, U.S.A
Plant Disease, 2017Co-Authors: Charles E. Flower, James M Slavicek, Nancy Hayes-plazolles, Cristina RosaAbstract:During the investigation of the sudden and early onset of yellowing and mortality of American elm (Ulmus Americana L.) trees at the USDA Forest Service Northern Research Station in Delaware, OH, a phytoplasma of the clover proliferation group (16SrVI) was detected as the putative causal agent of the disease outbreak.
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first report of candidatus phytoplasma trifolii related strain of 16srvi a phytoplasma subgroup associated with elm yellows disease in american elm Ulmus Americana l in ohio u s a
Plant Disease, 2017Co-Authors: Charles E. Flower, James M Slavicek, Nancy Hayesplazolles, Cristina RosaAbstract:During the investigation of the sudden and early onset of yellowing, followed by mortality of American elm (Ulmus Americana L.) trees at the USDA Forest Service Northern Research Station in Delaware, Ohio, a phytoplasma of the clover proliferation group (16SrVI) was detected as the putative causal agent of the disease outbreak. Onset of symptoms was rapid and widespread, occurring in late July 2016 and affecting ∼60 trees across two elm research plantations. Symptoms included a general yellowing of individual tree canopies, epinasty of foliage throughout the canopy, phloem discoloration, and on a subset of trees, a strong odor of methyl salicylate (observed in phloem tissue extracted from the lower stem). Similar symptoms in elms have been attributed to the classic elm yellows ‘Candidatus Phytoplasma ulmi’ (16SrV-A) (Lee et al. 2004) and the Illinois elm yellows phytoplasma (16SrVI-C) (Jacobs et al. 2003). In July 2016, samples were collected from 12 symptomatic and 8 asymptomatic American elm trees. DNA from the leaf midrib and branch phloem was isolated and analyzed for phytoplasma via seminested polymerase chain reactions (PCR). PCRs were first primed by phytoplasma universal primer pair P5/P7 (Jomantiene et al. 1998), followed by P7 and the reverse complement of the universal phytoplasma primer R16R2 for amplification of the phytoplasma 16S-23 ribosomal (r) DNA (16S-23 rRNA gene) sequences as per Gundersen and Lee (1996). The predicted band size of the second PCR product is 487 base pair (bp). The product bands were isolated, purified, and sequenced using primer P7. Sequencing results of the PCR products indicated that nine of the symptomatic and one of the asymptomatic American elm trees tested were infected by a phytoplasma. A BLAST search of the DNA sequences indicated high similarities to members of the ‘Ca. P. trifolii’ group 16SrVI-A. The sequences of all 10 phytoplasma-infected trees were identical to each other. To further confirm that a strain of ‘Ca. P. trifolii’ was infecting the elms, a PCR product was cloned and sequenced. The 1,557 bp band was the product of primers P1a/P7, followed by PCR primers designed from the sequence of ‘Ca. P. trifolii’. This band was cloned into the pMiniT 2.0 vector. Plasmid sequencing used standard sequencing primers (SP6 and T7 promoters), the primers included with the vector, and finally, custom designed phytoplasma primers that eliminate other bacterial DNA from getting amplified. The entire plasmid clone was sequenced in both directions with four to six times of coverage per base. Determination of the phytoplasma classification group was based on the nucleotide sequence within the phytoplasma universal primers F2n/R2 PCR fragment within the 16Sr gene. Using iPhyClassifier, the online tool for phytoplasma classification and taxonomic assignment (https://plantpathology.ba.ars.usda.gov/cgi-bin/resource/iphyclassifier.cgi), the sequence similarity between the Delaware elm phytoplasma and ‘Ca. P. trifolii’ (GenBank accession no. AB279597.1) is 99.9% in the 16Sr region, which places the Delaware elm phytoplasma in the 16SrVI-A group. The sequence of the plasmid was deposited in GenBank under accession number MF385584. Elm decline and yellows diseases in North America have been associated with the Illinois elm yellows phytoplasma (16SrVI-C, GenBank accession no. AF268893.1) (Jacobs et al. 2003), ‘Ca. Phytoplasma ulmi’ (16SrV-A) (Lee et al. 2004), and phytoplasma in the aster yellows group (16SrI-C) (Lee et al. 1995).
Louis Bernier - One of the best experts on this subject based on the ideXlab platform.
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identification and monitoring of Ulmus Americana transcripts during in vitro interactions with the dutch elm disease pathogen ophiostoma novo ulmi
Physiological and Molecular Plant Pathology, 2010Co-Authors: Mirella Aoun, Volker Jacobi, Brian Boyle, Louis BernierAbstract:Molecular mechanisms underlying the interaction leading to Dutch elm disease were studied in vitro using Ulmus Americana L. callus culture inoculated with budding cells of the fungal pathogen Ophiostoma novo-ulmi (Brasier). An interaction cDNA library employing suppression subtractive hybridization was constructed from infected elm callus tissue 72 h post-inoculation. Five hundred and thirty-five expressed sequence tags, mostly from the host, were grouped into 314 unisequences and distributed into functional categories. After differential screening, 53 U. Americana unisequences were considered upregulated during the interaction. The expression profiles at six time points of a subset of 18 elm transcripts were analyzed in more detail by quantitative reverse-transcriptase polymerase chain reaction. Upregulated sequences included transcripts with sequence similarity to genes coding for different classes of pathogenesis-related proteins and enzymes belonging to different branches of the phenylpropanoid pathway. The possible association with compartmentalization-related compounds and phytoalexin production is discussed. This study provides, for the first time, snapshots of molecular mechanisms involved in the compatible interaction between U. Americana and O. novo-ulmi. The interaction library dataset also represents a valuable genomic resource for the highly appreciated urban tree U. Americana.
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fungal colonization and host defense reactions in Ulmus Americana callus cultures inoculated with ophiostoma novo ulmi
Phytopathology, 2009Co-Authors: Mirella Aoun, D Rioux, M Simard, Louis BernierAbstract:ABSTRACT The host–pathogen interaction leading to Dutch elm disease was analyzed using histo- and cyto-chemical tests in an in vitro system. Friable and hard susceptible Ulmus Americana callus cultures were inoculated with the highly aggressive pathogen Ophiostoma novo-ulmi. Inoculated callus tissues were compared with water-treated callus tissues and studied with light microscopy (LM), transmission-electron microscopy (TEM), and scanning-electron microscopy (SEM). New aspects of this interaction are described. These include the histological observation, for the first time in plant callus cultures, of suberin with its typical lamellar structure in TEM and the intracellular presence of O. novo-ulmi. Expression of the phenylalanine ammonia lyase gene, monitored by real-time quantitative polymerase chain reaction, was correlated with the accumulation of suberin, phenols, and lignin in infected callus cultures. This study validates the potential use of the in vitro system for genomic analyses aimed at identif...
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Assessment of Phaeotheca dimorphospora for biological control of the Dutch elm disease pathogens, Ophiostoma ulmi and O. novo‐ulmi
Plant Pathology, 1996Co-Authors: Louis Bernier, G. B. Ouellette, D. Yang, M. DessureaultAbstract:The antagonistic fungus Phaeotheca dimorphospora was tested as a biocontrol agent against the Dutch elm disease pathogens, Ophiostoma ulmi and 0. novo-ulmi, on Ulmus Americana seedlings in the glasshouse. Curative inoculation of seedlings with P. dimorphospora had no significant effect on disease development. Conditioning inoculation of seedlings with the antagonist protected them against 0. ulmi but not against the more aggressive 0. novo-ulmi. In seedlings challenged with both the antagonist and either one of the pathogens, P. dimorphospora only spread locally around the inoculation point; however, the pathogens spread systemically throughout the whole plant. O. novo-ulmi survived in the region colonized by P. dimorphospora, whereas 0. ulmi did not.
