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David F. Karnosky - One of the best experts on this subject based on the ideXlab platform.
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Gene expression responses of paper birch (Betula papyrifera) to elevated CO2 and O3 during leaf maturation and senescence.
Environmental pollution (Barking Essex : 1987), 2009Co-Authors: Sari Kontunen-soppela, Elina Oksanen, Juha Parviainen, Hanna Ruhanen, Mikael Brosché, Markku Keinänen, R. Thakur, Mikko Kolehmainen, Jaakko Kangasjärvi, David F. KarnoskyAbstract:Abstract Gene expression responses of paper birch ( Betula papyrifera ) leaves to elevated concentrations of CO 2 and O 3 were studied with microarray analyses from three time points during the summer of 2004 at Aspen FACE. Microarray data were analyzed with clustering techniques, self-organizing maps, K -means clustering and Sammon's mappings, to detect similar gene expression patterns within sampling times and treatments. Most of the alterations in gene expression were caused by O 3 , alone or in combination with CO 2 . O 3 induced defensive reactions to oxidative stress and earlier leaf senescence, seen as decreased expression of photosynthesis- and carbon fixation-related genes, and increased expression of senescence-associated genes. The effects of elevated CO 2 reflected surplus of carbon that was directed to synthesis of secondary compounds. The combined CO 2 + O 3 treatment resulted in differential gene expression than with individual gas treatments or in changes similar to O 3 treatment, indicating that CO 2 cannot totally alleviate the harmful effects of O 3 .
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Leaf size and surface characteristics of Betula papyrifera exposed to elevated CO2 and O3.
Environmental pollution (Barking Essex : 1987), 2009Co-Authors: Johanna Riikonen, Kevin E. Percy, Minna Kivimäenpää, Mark E. Kubiske, Neil D. Nelson, Elina Vapaavuori, David F. KarnoskyAbstract:Betula papyrifera trees were exposed to elevated concentrations of CO2 (1.4 � ambient), O3 (1.2 � ambient) or CO2 þ O3 at the Aspen Free-air CO2 Enrichment Experiment. The treatment effects on leaf surface characteristics were studied after nine years of tree exposure. CO2 and O3 increased epidermal cell size and reduced epidermal cell density but leaf size was not altered. Stomatal density remained unaffected, but stomatal index increased under elevated CO2. Cuticular ridges and epicuticular wax crystallites were less evident under CO2 and CO2 þ O3. The increase in amorphous deposits, particularly under CO2 þ O3, was associated with the appearance of elongated plate crystallites in stomatal chambers. Increased proportions of alkyl esters resulted from increased esterification of fatty acids and alcohols under elevated CO2 þ O3. The combination of elevated CO2 and O3 resulted in different responses than expected under exposure to CO2 or O3 alone.
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effects of decadal exposure to interacting elevated co2 and or o3 on paper birch Betula papyrifera reproduction
Environmental Pollution, 2008Co-Authors: Joseph N.t. Darbah, Mark E. Kubiske, Neil D. Nelson, Elina Vapaavuori, Elina Oksanen, David F. KarnoskyAbstract:We studied the effects of long-term exposure (nine years) of birch (Betula papyrifera) trees to elevated CO2 and/or O3 on reproduction and seedling development at the Aspen FACE (Free-Air Carbon Dioxide Enrichment) site in Rhinelander, WI. We found that elevated CO2 increased both the number of trees that flowered and the quantity of flowers (260% increase in male flower production), increased seed weight, germination rate, and seedling vigor. Elevated O3 also increased flowering but decreased seed weight and germination rate. In the combination treatment (elevated CO2 + O3) seed weight is decreased (20% reduction) while germination rate was unaffected. The evidence from this study indicates that elevated CO2 may have a largely positive impact on forest tree reproduction and regeneration while elevated O3 will likely have a negative impact.
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Effects of decadal exposure to interacting elevated CO2 and/or O3 on paper birch (Betula papyrifera) reproduction.
Environmental pollution (Barking Essex : 1987), 2008Co-Authors: Joseph N.t. Darbah, Mark E. Kubiske, Neil D. Nelson, Elina Vapaavuori, Elina Oksanen, David F. KarnoskyAbstract:We studied the effects of long-term exposure (nine years) of birch (Betula papyrifera) trees to elevated CO2 and/or O3 on reproduction and seedling development at the Aspen FACE (Free-Air Carbon Dioxide Enrichment) site in Rhinelander, WI. We found that elevated CO2 increased both the number of trees that flowered and the quantity of flowers (260% increase in male flower production), increased seed weight, germination rate, and seedling vigor. Elevated O3 also increased flowering but decreased seed weight and germination rate. In the combination treatment (elevated CO2 + O3) seed weight is decreased (20% reduction) while germination rate was unaffected. The evidence from this study indicates that elevated CO2 may have a largely positive impact on forest tree reproduction and regeneration while elevated O3 will likely have a negative impact.
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Carbon gain and bud physiology in Populus tremuloides and Betula papyrifera grown under long-term exposure to elevated concentrations of CO2 and O3.
Tree physiology, 2008Co-Authors: Johanna Riikonen, Mark E. Kubiske, Neil D. Nelson, Elina Vapaavuori, Joseph N.t. Darbah, Elina Oksanen, Karte Kets, Anu Sõber, David F. KarnoskyAbstract:Paper birch (Betula papyrifera Marsh.) and three trembling aspen clones (Populus tremuloides Michx.) were studied to determine if alterations in carbon gain in response to an elevated concentration of CO 2 ([CO 2 ]) or O 3 ([O 3 ]) or a combination of both affected bud size and carbohydrate composition in autumn, and early leaf development in the following spring. The trees were measured for gas exchange, leaf size, date of leaf abscission, size and biochemical characteristics of the overwintering buds and early leaf development during the 8th-9th year of free-air CO 2 and O 3 exposure at the Aspen FACE site located near Rhinelander, WI. Net photosynthesis was enhanced 49-73% by elevated [CO 2 ], and decreased 13-30% by elevated [O 3 ]. Elevated [CO 2 ] delayed, and elevated [O 3 ] tended to accelerate, leaf abscission in autumn. Elevated [CO 2 ] increased the ratio of monosaccharides to di- and oligosaccharides in aspen buds, which may indicate a lag in cold acclimation. The total carbon concentration in overwintering buds was unaffected by the treatments, although elevated [O 3 ] decreased the amount of starch by 16% in birch buds, and reduced the size of aspen buds, which may be related to the delayed leaf development in aspen during the spring. Elevated [CO 2 ] generally ameliorated the effects of elevated [O 3 ]. Our results show that both elevated [CO 2 ] and elevated [O 3 ] have the potential to alter carbon metabolism of overwintering buds. These changes may cause carry-over effects during the next growing season.
Bert R. Mead - One of the best experts on this subject based on the ideXlab platform.
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ocular estimates of understory vegetation structure in a closed picea glauca Betula papyrifera forest
Journal of Vegetation Science, 2000Co-Authors: W.s. Willem, Bert R. MeadAbstract:. Horizontal/vertical profiling is a method used to assess vegetation space occupancy. This study investigated consistency and repeatability of measurements made on plots designed to describe forest understory vegetation structure. 20 circular, 100-m2 plots were measured by six independent observers, three times during the summer of 1997. The plots, located in south-central Alaska, were established in a closed Picea glauca (white spruce)/Betula papyrifera (paper birch) forest. Consistency and repeatability of measurements were evaluated by examining components of variance. Response variables were absolute and relative canopy cover. Results indicate that observers were not consistent relative to each other estimating vegetative cover from one plot to the next and from one measurement period to the next, making measurements unrepeatable.
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Ocular estimates of understory vegetation structure in a closed Picea glauca/Betula papyrifera forest
Journal of Vegetation Science, 2000Co-Authors: Hees, W.s. Willem, Bert R. MeadAbstract:. Horizontal/vertical profiling is a method used to assess vegetation space occupancy. This study investigated consistency and repeatability of measurements made on plots designed to describe forest understory vegetation structure. 20 circular, 100-m2 plots were measured by six independent observers, three times during the summer of 1997. The plots, located in south-central Alaska, were established in a closed Picea glauca (white spruce)/Betula papyrifera (paper birch) forest. Consistency and repeatability of measurements were evaluated by examining components of variance. Response variables were absolute and relative canopy cover. Results indicate that observers were not consistent relative to each other estimating vegetative cover from one plot to the next and from one measurement period to the next, making measurements unrepeatable.
André Pichette - One of the best experts on this subject based on the ideXlab platform.
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Properties of mixed particleboards based on white birch (Betula papyrifera) inner bark particles and reinforced with wood fibres
European Journal of Wood and Wood Products, 2008Co-Authors: Roger Pedieu, Bernard Riedl, André PichetteAbstract:The use of white birch (Betula papyrifera) inner bark particles as a raw material for panel manufacture is more profitable than their use for energy production. The objective of this study was to manufacture three layers mixed particleboards based on white birch inner bark particles in the core and reinforced with wood fibres in the face. Two manufacturing factors were taken into account: the percentage of wood fibres in the surface and the percentage of wood fibres added to white birch inner bark particles in the core. The panel with 25% fibres in the surface and 9% fibres added to white birch inner bark particles in the core had the best mechanical properties for M-1 grade of particleboards and 120 grade of medium density fiberboards. Only panel with 22% fibres in the surface and 5% fibres added to white birch inner bark particles in the core passed the standard for the linear expansion.
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Properties of white birch (Betula papyrifera) outer bark particleboards with reinforcement of coarse wood particles in the core layer
Annals of Forest Science, 2008Co-Authors: Roger Pedieu, Bernard Riedl, André PichetteAbstract:• This study proposes substituting traditional raw materials in the surface layers of wood particle-boards with the water resistant white birch (Betula papyrifera) outer bark particles, which can help improve the dimensional stability of manufactured mixed particleboards, thereby alleviating shortages of raw material in a cost-efficient manner. • Mixed particleboards were fabricated in the laboratory using untreated or alkali treated white birch outer bark particles as substitute material. These particles were resinated successively with three percentages of phenol-formaldehyde resin. Overall, the results of this study clearly demonstrate that the panels could be manufactured using up to 45% of the proposed substitute material and still maintain the required mechanical and physical properties. • Alkali treatment was used to remove natural wax from bark particles surface which hinders resin adhesion. This treatment negatively affected mechanical and physical properties of finished panels and the variation of phenol-formaldehyde resin percentage in the bark particles significantly affected only their hardness. • Panel with untreated bark particles in the surface layers, resinated with 5% phenol-formaldehyde resin was selected as the best with the help of a statistical analysis carried out in a factorial complete block design, especially from the dimensional stability criterion.
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Properties of white birch (Betula papyrifera) outer bark particleboards with reinforcement of coarse wood particles in the core layer
Annals of Forest Science, 2008Co-Authors: Roger Pedieu, Bernard Riedl, André PichetteAbstract:• L’objet de cette étude est de substituer la matière première traditionnelle dans les couches couvrantes des panneaux de particules conventionnelles par les particules hydrophobes d’écorce externe de bouleau blanc ( Betula papyrifera ) qui peuvent aider à améliorer la stabilité dimensionnelle des panneaux mixtes produits et ainsi permettre d’alléger la pénurie de la matière première d’une manière rentable. • Les panneaux de particules mixtes ont été fabriqués à l’échelle du laboratoire en utilisant les particules d’écorce externe de bouleau blanc non traitées ou traitées à la soude comme matériel de substitution. Ces particules ont été encollées successivement avec trois pourcentages de colle phénol-formaldéhyde. Les résultats de cette étude démontrent d’un bout à l’autre que les panneaux pourraient être fabriqués en utilisant jusqu’à 45 % de matière de substitution proposée et maintenir toujours les exigences des propriétés mécaniques et physiques. • Le traitement à la soude a été utilisé afin d’enlever la cire naturelle de la surface des écorces qui empêche l’adhésion de la colle. Ce traitement a affecté négativement les propriétés mécaniques et physiques des panneaux produits et la variation du pourcentage de la colle phénol-formaldéhyde dans les particules d’écorce a affecté leur dureté de manière hautement significative. • Le panneau avec les particules d’écorce non traitées dans les couches couvrantes et encollées avec 5 % de phénol-formaldéhyde a été sélectionné comme le meilleur à l’aide d’une analyse statistique faite dans un plan factoriel en blocs complets, en se basant sur le critère de la stabilité dimensionnelle. • This study proposes substituting traditional raw materials in the surface layers of wood particle-boards with the water resistant white birch ( Betula papyrifera ) outer bark particles, which can help improve the dimensional stability of manufactured mixed particleboards, thereby alleviating shortages of raw material in a cost-efficient manner. • Mixed particleboards were fabricated in the laboratory using untreated or alkali treated white birch outer bark particles as substitute material. These particles were resinated successively with three percentages of phenol-formaldehyde resin. Overall, the results of this study clearly demonstrate that the panels could be manufactured using up to 45% of the proposed substitute material and still maintain the required mechanical and physical properties. • Alkali treatment was used to remove natural wax from bark particles surface which hinders resin adhesion. This treatment negatively affected mechanical and physical properties of finished panels and the variation of phenol-formaldehyde resin percentage in the bark particles significantly affected only their hardness. • Panel with untreated bark particles in the surface layers, resinated with 5% phenol-formaldehyde resin was selected as the best with the help of a statistical analysis carried out in a factorial complete block design, especially from the dimensional stability criterion.
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Anticancer diarylheptanoid glycosides from the inner bark of Betula papyrifera
Phytochemistry, 2007Co-Authors: Vakhtang Mshvildadze, Jean Legault, Serge Lavoie, Charles Gauthier, André PichetteAbstract:Abstract Phytochemical investigations of the MeOH extract of Betula papyrifera inner bark led to the isolation of ten phenolic compounds of the following types: diarylheptanoid glycosides ( 1 – 4 ), a diarylheptanoid ( 5 ), a lignan ( 6 ), flavonoids ( 7 – 8 ) and chavicol glycosides ( 9 – 10 ). Among them, the diarylheptanoid glycoside, ( S )-1,7-bis-(4-hydroxyphenyl)-heptan-3-one-5- O -α- l -arabinofuranosyl-(1 → 6)-β- d -glucopyranoside, papyriferoside A ( 1 ), was isolated and its structure was determined on the basis of 1D and 2D NMR, HPLC-MS, as well as high resolution mass spectroscopic data. Platyphylloside ( 4 ) exerted the strongest cytotoxic activity of all isolated compounds with IC 50 values ranging from 10.3 to 13.8 μM.
Janusz J. Zwiazek - One of the best experts on this subject based on the ideXlab platform.
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Effects of iron and root zone pH on growth and physiological responses of paper birch (Betula papyrifera), trembling aspen (Populus tremuloides) and red-osier dogwood (Cornus stolonifera) seedlings in a split-root hydroponic system
Acta Physiologiae Plantarum, 2019Co-Authors: Feng Xu, Xiangfeng Tan, Wen-qing Zhang, Janusz J. ZwiazekAbstract:Iron deficiency that is induced by high soil pH is a major factor affecting plant growth in calcareous soils and in some areas that have been reclaimed following industrial activities. Since the effects of high soil pH commonly involve Fe deficiency, in this study, we examined whether Fe provided to part of the root system exposed to low pH would alleviate high pH stress in paper birch ( Betula papyrifera ), trembling aspen ( Populus tremuloides ) and red-osier dogwood ( Cornus stolonifera ) seedlings. The plants were grown in a controlled environment growth room in mineral nutrient solution at pH 5 and 9 and provided with either 0 or 40 µM Fe in a split-root system for 8 weeks. At the end of the treatments, plant dry weights, net photosynthesis, transpiration rates, root ferric-chelate reductase activity, and leaf chlorophyll concentrations were measured, and elemental analyses were carried out in young leaves. The results demonstrated high root zone pH affected Fe, P and Zn concentrations in young leaves. In the three considered species, plants with part of their root system exposed to pH 5 had higher dry weights, net photosynthesis, and transpiration rates compared with the plants with the whole root system immersed in pH 9 solution. High root zone pH reduced photosynthesis, transpiration rates, leaf chlorophyll concentrations and the uptake of Fe, P, and Zn in plants. Partial exposure of the root system to low pH and Fe supply reduced leaf chlorosis and partly alleviated the high pH stress in the studied plants by improving Fe uptake, but did not alleviate root growth reductions.
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Effects of root medium pH on root water transport and apoplastic pH in red-osier dogwood (Cornus sericea) and paper birch (Betula papyrifera) seedlings.
Plant biology (Stuttgart Germany), 2016Co-Authors: W. Zhang, Janusz J. ZwiazekAbstract:Soil pH is a major factor affecting plant growth. Plant responses to pH conditions widely vary between different species of plants. However, the exact mechanisms of high pH tolerance of plants are largely unknown. In the present study, we compared the pH responses of paper birch (Betula papyrifera) seedlings, a relatively sensitive species to high soil pH, with red-osier dogwood (Cornus sericea), reported to be relatively tolerant of high pH conditions. We examined the hypotheses that tolerance of plants to high root zone pH is linked to effective control of root apoplastic pH to facilitate nutrient and water transport processes In the study, we exposed paper birch and red-osier dogwood seedlings for six weeks to pH 5, 7 and 9 under controlled-environment conditions in hydroponic culture. Then, we measured biomass, gas exchange, root hydraulic conductivity, ferric chelate reductase (FCR) activity, xylem sap pH and the relative abundance of major elements in leaf protoplasts and apoplasts. The study sheds new light on the rarely studied high pH tolerance mechanisms in plants. We found that compared with paper birch, red-osier dogwood showed greater growth, higher gas exchange, and maintained higher root hydraulic conductivity as well as lower xylem sap pH under high pH conditions. The results suggest that the relatively high pH tolerance of dogwood is associated with greater water uptake ability and maintenance of low apoplastic pH. These traits may have a significant impact on the uptake of Fe and Mn by leaf cells.
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Responses of ectomycorrhizal Populus tremuloides and Betula papyrifera seedlings to salinity
Environmental and Experimental Botany, 2008Co-Authors: Mónica Calvo Polanco, Michael D. Mackinnon, Janusz J. ZwiazekAbstract:Abstract Roots of trembling aspen (Populus tremuloides Michx.) and paper birch (Betula papyrifera Marsh.) seedlings were inoculated with Hebeloma crustuliniforme or Laccaria bicolor and treated with 25 mM NaCl for 6 weeks. Both tree species appeared to be relatively tolerant of the applied NaCl treatment and did not develop visible leaf symptoms that are characteristic of salt injury. Salt treatment reduced total dry weights in aspen and birch, but did not significantly affect transpiration rates and root hydraulic conductance. Salt-treated ectomycorrhizal aspen maintained higher root hydraulic conductance compared with non-mycorrhizal plants. Na and Cl concentrations increased in shoots and roots of mycorrhizal and non-mycorrhizal aspen and birch in response to NaCl treatment. Roots of NaCl-treated aspen inoculated with H. crustuliniforme had over twofold higher concentrations of Na compared with non-mycorrhizal NaCl-treated plants. Similarly to aspen, Na and Cl concentrations increased in roots and shoots of NaCl-treated birch seedlings. However, in birch, there were no significant differences in Na and Cl concentrations between mycorrhizal and non-mycorrhizal plants. The results suggest that salt exclusion by the ectomycorrhizal associations is host-specific or/and that the processes leading to salt exclusion are activated in ectomycorrhizal plants by a threshold salt level which may vary between plant species.
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Effects of root medium pH on water transport in paper birch (Betula papyrifera) seedlings in relation to root temperature and abscisic acid treatments.
Tree physiology, 2004Co-Authors: M. Kamaluddin, Janusz J. ZwiazekAbstract:We investigated the effects of root medium pH on water transport in whole-plant and detached roots of paper birch (Betula papyrifera Marsh.). Exposure of seedling roots to pH 4 and 8 significantly decreased root hydraulic conductivity (Lp) and stomatal conductance (gs), compared with pH 6. When roots of solution-culture-grown (pH 6) seedlings were transferred to pH 4 or 8, their steady-state water flow (Qv) declined within minutes, followed by a decline in gs. The root oxygen uptake rates were not significantly affected by the pH treatments. Treatment of roots with mercuric chloride resulted in a large decrease in Qv at pH 6; the extent of this decrease was similar to that brought about by pH 4 and 8. Lowering root temperature from 21 to 4 degrees C decreased Qv irrespective of medium pH. Low root temperatures did not offset the effects of medium pH 4 on Qv and the roots in this treatment had a high activation energy for water flow. Conversely, roots exposed to pH 8 had a low activation energy, similar to that at pH 6. When 2 micro M abscisic acid, (+/-)-cis-trans-ABA, was added to the root medium, Qv increased in roots that were incubated at pH 6. It also increased slightly in roots incubated at pH 4, but not at pH 8. The increase at pH 4 and 6 was temperature-dependent, occurring at 21 degrees C, but not 4 degrees C. We suggest that the pH treatments are responsible for altering root water flow properties through their effects on the activity of water channels. These results support the concept that ABA effects on water channels are modulated by other, possibly metabolic- and pH-dependent factors.
Gabriel Theriault - One of the best experts on this subject based on the ideXlab platform.
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Nickel and Copper Toxicity and Plant Response Mechanisms in White Birch ( Betula papyrifera )
Bulletin of environmental contamination and toxicology, 2016Co-Authors: Gabriel Theriault, Kabwe NkongoloAbstract:Nickel (Ni) and copper (Cu) are the most prevalent metals found in the soils in the Greater Sudbury Region (Canada) because of smelting emissions. The main objectives of the present study were to (1) determine the toxicity of nickel (Ni) and copper (Cu) at different doses in Betula papyrifera (white birch), (2) Characterize nickel resistance mechanism, and (3) assess segregating patterns for Ni and Cu resistance in B. papyrifera populations. This study revealed that B. papyrifera is resistant to Ni and Cu concentrations equivalent to the levels reported in metal-contaminated stands in the GSR. Resistant genotypes (RG) accumulate Ni in roots but not in leaves. Moderately susceptible (MSG) and susceptible genotypes (SG) show a high level of Ni translocation to leaves. Gene expression analysis showed differential regulation of genes in RG compared to MSG and SG. Analysis of segregation patterns suggests that resistance to Ni and Cu is controlled by single recessive genes.
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Comprehensive Transcriptome Analysis of Response to Nickel Stress in White Birch (Betula papyrifera).
PloS one, 2016Co-Authors: Gabriel Theriault, Paul Michael, Kabwe NkongoloAbstract:White birch (Betula papyrifera) is a dominant tree species of the Boreal Forest. Recent studies have shown that it is fairly resistant to heavy metal contamination, specifically to nickel. Knowledge of regulation of genes associated with metal resistance in higher plants is very sketchy. Availability and annotation of the dwarf birch (B. nana) enables the use of high throughout sequencing approaches to understanding responses to environmental challenges in other Betula species such as B. papyrifera. The main objectives of this study are to 1) develop and characterize the B. papyrifera transcriptome, 2) assess gene expression dynamics of B. papyrifera in response to nickel stress, and 3) describe gene function based on ontology. Nickel resistant and susceptible genotypes were selected and used for transcriptome analysis. A total of 208,058 trinity genes were identified and were assembled to 275,545 total trinity transcripts. The transcripts were mapped to protein sequences and based on best match; we annotated the B. papyrifera genes and assigned gene ontology. In total, 215,700 transcripts were annotated and were compared to the published B. nana genome. Overall, a genomic match for 61% transcripts with the reference genome was found. Expression profiles were generated and 62,587 genes were found to be significantly differentially expressed among the nickel resistant, susceptible, and untreated libraries. The main nickel resistance mechanism in B. papyrifera is a downregulation of genes associated with translation (in ribosome), binding, and transporter activities. Five candidate genes associated to nickel resistance were identified. They include Glutathione S–transferase, thioredoxin family protein, putative transmembrane protein and two Nramp transporters. These genes could be useful for genetic engineering of birch trees.
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Decrypting the regulation and mechanism of nickel resistance in white birch (Betula papyrifera) using cross-species metal-resistance genes
Genes & Genomics, 2016Co-Authors: Gabriel Theriault, Paul Michael, Kabwe NkongoloAbstract:Recent studies have found that many transporters, metabolic products and chelators play a role in heavy metal (HM) resistance in model plants. Knowledge of mechanisms involved in resistance to HM in higher plant species is limited. In the present study, the expression of four novel genes (AT2G16800, GR, ZAT11, and IREG1) in white birch ( Betula papyrifera ) growing in soil contaminated with different levels of nickel were investigated. B. papyrifera seedlings were treated with different doses of nickel including 5.56, 1600, and 4800 mg/kg in growth chamber screening trials. The expression of targeted genes in nickel resistant and susceptible genotypes was measured using RT-qPCR. Field trials were also conducted to assess the regulation of these genes in B. papyrifera growing in metal-contaminated and uncontaminated sites. The transcription factor ZAT11 was the only gene affected (downregulation) by nickel at the low dose of 5.56 mg/kg. The expression of all the four genes was affected by the high dose of 1600 mg/kg resulting in the downregulation of AT2G16800, GR, and ZAT11 and the upregulation of IREG1. ZAT11 and IREG1 were differentially expressed in resistant genotypes. No differences in gene expression were found when samples from metal-contaminated and reference field sites were compared, but the expression of AT2G16800 and IREG1 was higher in roots compared to leaves. The findings of this study suggest that the bioavailable amounts of nickel that is usually found in highly metal-contaminated soils in mining regions cannot trigger a measurable genetic response in plants.
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Contrasting Effects of Metal Contaminations and Soil Liming on Cations Exchange Capacity and Global DNA Methylation in Betula papyrifera Populations from a Mining Region
American Journal of Environmental Sciences, 2016Co-Authors: Gabriel Theriault, Kabwe NkongoloAbstract:The Greater Sudbury Region in Northern Ontario (Canada) has been one of the most contaminated regions in the world. Soil liming with dolomitic limestone applications has decreased significantly the level of soil acidity resulting in forest regeneration. This reclamation process does not affect the level of soil metal contamination but results in metals availability decrement. The coping mechanisms of birch (Betula papyrifera) to soil metal contamination have been recently characterized. The objective of this study was to assess the effects of soil liming and metal contamination on Cations Exchange Capacity (CEC) and whole DNA methylation in B. papyrifera. Cytosine and adenine methylations were measured using tandem Mass Spectrometry (MS/MS) coupled with LC (LC-MS/MS). The present study confirms that liming increases significantly soil pH even over 30 years after dolomitic applications. There was a decrease of cations exchange capacity and cytosine methylation in metal-contaminated sites compared to uncontaminated sites. CEC was significantly higher (p≤0.05) in limed and reference distal sites compared to unlimed areas. No significant difference in cytosine methylation level was observed between metal-contaminated limed and unlimed areas. This suggests that metal contamination mostly nickel and copper, the main elements found in higher concentrations in contaminated sites might be associated with cytosine methylation.
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Candidate genes involved in nickel resistance of white birch (Betula papyrifera).
2016Co-Authors: Gabriel Theriault, Paul Michael, Kabwe NkongoloAbstract:Candidate genes involved in nickel resistance of white birch (Betula papyrifera).