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phytochemistry of the salicaceae. v. the use of a gas-liquid chromatographic screening test to detect phytochemical variations in populus deltoides marsh. 19734745800
degradation of trichloroethylene in wetland microcosms containing broad-leaved cattail and eastern cottonwood.remediation of aquifers containing trichloroethylene (tce) relies primarily on physical extraction of contaminated groundwater and soil. unfortunately, this is typically expensive and does not always attain the desired treatment goals. in situ bioremediation via natural attenuation is an alternative treatment process in which tce is transformed by indigenous microorganisms and plants. in this study, tce was observed in a surficial aquifer that discharges into a wetland. experiments were undertak ...200211996342
increased leaf area expansion of hybrid poplar in elevated co2. from controlled environments to open-top chambers and to face.we examined the response of hybrid poplar to elevated co2 in contrasting growth environments: controlled environment chamber (ce). open-top chamber (otc) and poplar free air co2 enrichment (popface) in order to compare short versus long-term effects and to determine whether generalisations in response are possible for this fast growing tree. leaf growth, which for poplar is an important determinant of stemwood productivity was followed in all environments, as were the determinants of leaf growth ...200111789926
molecular characterization and distribution of a 145-bp tandem repeat family in the genus populus.this report aims to describe the identification and molecular characterization of a 145-bp tandem repeat family that accounts for nearly 1.5% of the populus genome. three members of this repeat family were cloned and sequenced from populus deltoides and p. ciliata. the dimers of the repeat were sequenced in order to confirm the head-to-tail organization of the repeat. hybridization-based analysis using the 145-bp tandem repeat as a probe on genomic dna gave rise to ladder patterns which were ide ...199910584311
polyphenol oxidase from hybrid poplar. cloning and expression in response to wounding and herbivory.the inducible expression of polyphenol oxidase (ppo), a presumed antiherbivore enzyme, was examined in hybrid poplar (populus trichocarpa x populus deltoides). following mechanical wounding simulating insect damage, ppo activity increased dramatically in wounded and unwounded leaves on wounded plants beginning at 24 and 48 h, respectively. a hybrid poplar ppo cdna was isolated and its nucleotide sequence determined. on northern blots, ppo transcripts were detected within 8 h of wounding, and rea ...200010982443
4-coumarate:coenzyme a ligase in hybrid poplar. properties of native enzymes, cdna cloning, and analysis of recombinant enzymes.the enzyme 4-coumarate:coenzyme a ligase (4cl) is important in providing activated thioester substrates for phenylpropanoid natural product biosynthesis. we tested different hybrid poplar (populus trichocarpa x populus deltoides) tissues for the presence of 4cl isoforms by fast-protein liquid chromatography and detected a minimum of three 4cl isoforms. these isoforms shared similar hydroxycinnamic acid substrate-utilization profiles and were all inactive against sinapic acid, but instability of ...19989489021
functional characterization and subcellular localization of poplar (populus trichocarpa x populus deltoides) cinnamate 4-hydroxylase.cinnamic acid 4-hydroxylase (c4h), a member of the cytochrome p450 monooxygenase superfamily, plays a central role in phenylpropanoid metabolism and lignin biosynthesis and possibly anchors a phenylpropanoid enzyme complex to the endoplasmic reticulum (er). a full-length cdna encoding c4h was isolated from a hybrid poplar (populus trichocarpa x p. deltoides) young leaf cdna library. rna-blot analysis detected c4h transcripts in all organs tested, but the gene was most highly expressed in develop ...200111351095
nonradioactive assay for cellular dimethylallyl diphosphate.a sensitive, nonradioactive method was developed to measure cellular levels of dimethylallyl diphosphate (dmapp), a central intermediate of isoprenoid metabolism in nature. the assay is based on the hydrolysis of dmapp in acid to the volatile hydrocarbon isoprene (2-methyl-1,3-butadiene), with subsequent analysis of isoprene by headspace gas chromatography with reduction gas detection. in the assay, cell samples are directly acidified with 4 m h(2)so(4) in sealed reaction vials. therefore, there ...200111355861
transgenic analysis of a hybrid poplar wound-inducible promoter reveals developmental patterns of expression similar to that of storage protein genes.the wound-inducible win3 multigene family from hybrid poplars (populus trichocarpa x populus deltoides) encodes proteins with structural similarities with kunitz-type protease inhibitors (h.d. bradshaw jr., j.b. hollick, t.j. parsons, h.r.g. clarke, m.p. gordon [1990] plant mol biol 14: 51-59), and at least one member, win3.12, is transcribed de novo in the injured and uninjured leaves of wounded trees (j.b. hollick, m.p. gordon [1993] plant mol biol 22: 561-572). a previous study demonstrated t ...19957480333
characteristics of pollen diffusates and pollen wall cytochemistry in poplars.pollen diffusates, known to be important in pollen-stigma interactions controlling interspecific incompatibility between populus deltoides and populus alba, have been partly characterized and shown to contain more than 20 protein bands by polyacrylamide gel electrophoresis, at least 4 of these being glycoproteins. seven fractions had antigenic activity in rabbits and several enzyme activities were also present. peroxidase and leucine aminopeptidase isoenzymes were detected in the diffusates, dem ...19807440650
repression of pseudomonas putida phenanthrene-degrading activity by plant root extracts and exudates.the phenanthrene-degrading activity (pda) of pseudomonas putida atcc 17484 was repressed after incubation with plant root extracts of oat (avena sativa), osage orange (maclura pomifera), hybrid willow (salix alba x matsudana), kou (cordia subcordata) and milo (thespesia populnea) and plant root exudates of oat (avena sativa) and hybrid poplar (populus deltoides x nigra dn34). total organic carbon content of root extracts ranged from 103 to 395 mg l(-1). characterization of root extracts identifi ...200415142245
phylogenetic and molecular evidence for allochronic speciation in gall-forming aphids (pemphigus).sympatric populations can diverge when variation in phenology or life cycle causes them to mate at distinctly different times. we report patterns consistent with this process (allochronic speciation) in north american gall-forming aphids, in the absence of a host or habitat shift. pemphigus populi-transversus riley and p. obesinymphae aoki form a monophyletic clade within the north american pemphigus group. they are sympatric on the eastern cottonwood, populus deltoides (salicaceae), but have di ...200415119438
responses of riparian cottonwoods to alluvial water table declines./ human demands for surface and shallow alluvial groundwater have contributed to the loss, fragmentation, and simplification of riparian ecosystems. populus species typically dominate riparian ecosystems throughout arid and semiarid regions of north american and efforts to minimize loss of riparian populus requires an integrated understanding of the role of surface and groundwater dynamics in the establishment of new, and maintenance of existing, stands. in a controlled, whole-stand field experi ...19999950697
a vegetative storage protein homolog is expressed in the growing shoot apex of hybrid poplar.the ability of poplars (populus deltoides bartr. ex marsh., and populus trichocarpa torr. and gray) to sequester nitrogen in stems in preparation for winter has been associated with the massive accumulation of protein bodies in the bark and xylem ray parenchyma. these protein bodies contain a bark storage protein (bsp) that can account for up to 30% of the total soluble bark protein during the winter months. perhaps the plant's ability to efficiently cycle nitrogen through bsp is an important as ...19979362569
detection in situ and characterization of lignin in the g-layer of tension wood fibres of populus deltoides.the occurrence of lignin in the additional gelatinous (g-) layer that differentiates in the secondary wall of hardwoods during tension wood formation has long been debated. in the present work, the ultrastructural distribution of lignin in the cell walls of normal and tension wood fibres from poplar (populus deltoides bartr. ex marshall) was investigated by transmission electron microscopy using cryo-fixation-freeze-substitution in association with immunogold probes directed against typical stru ...200415067547
autumnal changes of sulfur fractions and the ratio of organic sulfur to total nitrogen in leaves and adjacent bark of eastern cottonwood, white basswood and actinorhizal black alder.autumnal changes in organic-s, sulfate-s, total-s and the ratios of organic-s to total-n and sulfate-s to organic-s were followed in leaves and adjacent bark of actinorhizal (frankia-nodulated) black alder (alnus glutinosa (l.) gaertn.) and eastern cottonwood (populus deltoides bartr. ex marsh.) trees growing on a minespoil site high in extractable soil sulfate, and in black alder and white basswood (tilia heterophylla venten.) trees growing on a prairie-derived soil in illinois. organic-s conce ...198814972822
loss of hydraulic conductivity due to water stress in intact juveniles of quercus rubra and populus deltoides.despite many studies of the percent loss of hydraulic conductivity in excised branches, there is doubt as to whether cutting stems in air introduces unnatural embolism into the xylem at the cut surface. to address this question, hydraulic conductivity was measured in seedlings of northern red oak (quercus rubra l.) and rooted scions of eastern cottonwood (populus deltoides bartr. ex marsh.) that had been droughted in pots. results indicate that in situ dehydration produced a very similar vulnera ...199214969978
biodegradation of nitro-substituted explosives 2,4,6-trinitrotoluene, hexahydro-1,3,5-trinitro-1,3,5-triazine, and octahydro-1,3,5,7-tetranitro-1,3,5-tetrazocine by a phytosymbiotic methylobacterium sp. associated with poplar tissues (populus deltoides x nigra dn34).a pink-pigmented symbiotic bacterium was isolated from hybrid poplar tissues (populus deltoides x nigra dn34). the bacterium was identified by 16s and 16s-23s intergenic spacer ribosomal dna analysis as a methylobacterium sp. (strain bj001). the isolated bacterium was able to use methanol as the sole source of carbon and energy, which is a specific attribute of the genus methylobacterium. the bacterium in pure culture was shown to degrade the toxic explosives 2,4,6-trinitrotoluene (tnt), hexahyd ...200414711682
poplar metal tolerance protein 1 confers zinc tolerance and is an oligomeric vacuolar zinc transporter with an essential leucine zipper motif.cation diffusion facilitator (cdf) proteins are a recently discovered family of cation efflux transporters that might play an essential role in metal homeostasis and tolerance. here, we describe the identification, characterization, and localization of ptdmtp1, a member of the cdf family from the hybrid poplar populus trichocarpa x populus deltoides. ptdmtp1 is expressed constitutively and ubiquitously, although at low levels. heterologous expression in yeast showed that ptdmtp1 was able to comp ...200314630973
molecular analysis of natural populations of populus nigra l intermingled with cultivated hybrids.in this study six simple sequence repeats (ssr or microsatellites) were selected for their ability to fingerprint a total of 60 commercial clones of populus deltoides marsh. and populus x canadensis moench (typically derived from crosses between populus nigra l and p. deltoides) and to characterize a natural population of p. nigra growing along the ticino river in the north of italy. out of six ssrs used, four microsatellite loci were found to have alleles which were species-specific to p. delto ...200312859627
rapid alkalinization factors in poplar cell cultures. peptide isolation, cdna cloning, and differential expression in leaves and methyl jasmonate-treated cells.a family of peptides inducing rapid ph alkalinization in hybrid poplar (populus trichocarpa x populus deltoides) cell culture medium was isolated from hybrid poplar leaves. five related approximately 5-kd peptides were purified by high-performance liquid chromatography and analyzed by matrix-assisted laser desorption ionization-mass spectrometry. the n-terminal sequence of one of the isolated peptides was very similar to a previously characterized peptide from tobacco (nicotiana tabacum), rapid ...200312586905
cloning, functional expression, and subcellular localization of multiple nadph-cytochrome p450 reductases from hybrid poplar.nadph:cytochrome p450 reductase (cpr) provides reducing equivalents to diverse cytochrome p450 monooxygenases. we isolated cdnas for three cpr genes (cpr1, cpr2, and cpr3) from hybrid poplar (populus trichocarpa x populus deltoides). deduced cpr2 and cpr3 amino acid sequences were 91% identical, but encoded isoforms divergent from cpr1 (72% identity). cpr1 and cpr2 were co-expressed together with the p450 enzyme cinnamate-4-hydroxylase (c4h) in yeast (saccharomyces cerevisiae). microsomes isolat ...200212481067
structure, inheritance, and expression of hybrid poplar (populus trichocarpa x populus deltoides) phenylalanine ammonia-lyase genes.a heterologous probe encoding phenylalanine ammonia-lyase (pal) was used to identify pal clones in cdna libraries made with rna from young leaf tissue of two populus deltoides x p. trichocarpa f1 hybrid clones. sequence analysis of a 2.4-kb cdna confirmed its identity as a full-length pal clone. the predicted amino acid sequence is conserved in comparison with that of pal genes from several other plants. southern blot analysis of popular genomic dna from parental and hybrid individuals, restrict ...19938108506
phytoremediation of subarctic soil contaminated with diesel fuel.the effects of several plant species, native to northern latitudes, and different soil amendments, on diesel fuel removal from soil were studied. plant treatments included scots pine (pinus sylvestris), poplar (populus deltoides x wettsteinii), a grass mixture (red fescue, fesuca rubra; smooth meadowgrass, poa pratensis and perennial ryegrass, lolium perenne) and a legume mixture (white clover, trifolium repens and pea, pisum sativum). soil amendments included npk fertiliser, a compost extract a ...200212118697
annotation of a 95-kb populus deltoides genomic sequence reveals a disease resistance gene cluster and novel class i and class ii transposable elements.poplar has become a model system for functional genomics in woody plants. here, we report the sequencing and annotation of the first large contiguous stretch of genomic sequence (95 kb) of poplar, corresponding to a bacterial artificial chromosome clone mapped 0.6 centimorgan from the melampsora larici-populina resistance locus. the annotation revealed 15 putative genetic objects, of which five were classified as hypothetical genes that were similar only with expressed sequence tags from poplar. ...200415085260
deposition velocities to sorbus aria, acer campestre, populus deltoides x trichocarpa 'beaupré', pinus nigra and x cupressocyparis leylandii for coarse, fine and ultra-fine particles in the urban environment.trees are effective in the capture of particles from urban air to the extent that they can significantly improve urban air quality. as a result of their aerodynamic properties conifers, with their smaller leaves and more complex shoot structures, have been shown to capture larger amounts of particle matter than broadleaved trees. this study focuses on the effects of particle size on the deposition velocity of particles (vg) to five urban tree species (coniferous and broadleaved) measured at two ...200515327866
hypersensitivity to common tree pollens in new york city patients.testing for tree pollen hypersensitivity typically requires the use of several tree pollens. identifying patterns of cross-sensitivity to tree pollens could reduce the number of trees used for testing. the goal of this study was to relate reported tree pollen levels to hypersensitivity patterns. three hundred seventy-one allergy patients were tested serologically for hypersensitivity toward prevalent tree pollens in the surrounding new york area over the years 1993-2000. specific tree pollens th ...200212221895
laboratory-scale measurements of n2o and ch4 emissions from hybrid poplars (populus deltoides x populus nigra).the purpose of this study was to determine whether or not young hybrid poplar (populus deltoides x populus nigra) could transport landfill biogas internally from the root zone to the atmosphere, thereby acting as conduits for landfill gas release. fluxes of methane (ch4) and nitrous oxide (n2o) from the seedlings to the atmosphere were measured under controlled conditions using dynamic flux chambers and a tunable diode laser trace gas analyser (tdltga). nitrous oxide was emitted from the seedlin ...200415666448
mycorrhizal inoculum potentials of pure reclamation materials and revegetated tailing sands from the canadian oil sand industry.recent improvements in the management of oil sand tailings used by the canadian oil sand industry have resulted in the production of composite tailing sands (ct): a new challenging material for reclamation work. jack pine (pinus banksiana lamb.), hybrid poplar (populus deltoides bartr. ex marsh. xpopulus nigra l.) and red clover (trifolium pratense l.) plants were used in an 8-week greenhouse bioassay to evaluate the mycorrhizal inoculum potential of ct. this inoculum potential was compared with ...200415883852
genetic architecture of qualitative and quantitative melampsora larici-populina leaf rust resistance in hybrid poplar: genetic mapping and qtl detection.in order to elucidate the genetic control of resistance to melampsora larici-populina leaf rust in hybrid poplars, a populus deltoides x p. trichocarpa f(1) progeny was analysed for qualitative and quantitative rust resistances. this progeny was evaluated for three components of quantitative resistance (latent period, uredinia number and uredinia size) to seven m. larici-populina strains in controlled conditions, and for one component of field susceptibility (rust colonization on the most infect ...200515948835
surface-enhanced raman spectroscopy of bacteria and pollen.a technique for distinguishing biological material based on surface-enhanced raman scattering (sers) is reported in this work. of particular interest is biological material that can be airborne. silver colloidal particles with diameters in the range 10 to 20 nm and with a characteristic ultraviolet-visible (uv-vis) absorption band at 400 nm were used to obtain sers spectra of escherichia coli, pseudomonas aeruginosa, and salmonella typhimurium bacteria and a number of tree and grass pollens (cup ...200516105210
chronic ozone exposure increases the susceptibility of hybrid populus to disease caused by septoria musiva.rooted cuttings of hybrid populus (dn34, populus deltoides x nigra) were grown outdoors in pots in open-top chambers at ithaca, ny (74.5 degrees w, 42.5 degrees n), during 1988 and 1989 (experiment 1) and during 1989 and 1990 (experiment 2). ambient air was passed through charcoal filters to produce a 0.5 times ambient ozone treatment, and ozone generated from oxygen was added to produce one and two times ambient ozone treatments. in experiment 1, treatments were applied for 8-12 h each day for ...199415091652
cyanide removal by chinese vegetation--quantification of the michaelis-menten kinetics.little is known about metabolism rates of environmental chemicals by vegetation. a good model compound to study the variation of rates among plant species is cyanide. vascular plants possess an enzyme system that detoxifies cyanide by converting it to the amino acid asparagine. knowledge of the kinetic parameters, the half-saturation constant (km) and the maximum metabolic capacity (vmax), is very useful for enzyme characterization and biochemical purposes. the goal of this study is to find the ...200516137157
phytoremediation of polycyclic aromatic hydrocarbons in manufactured gas plant-impacted soil.contamination of soil by hazardous substances poses a significant threat to human, environmental, and ecological health. cleanup of the contaminants using destructive, invasive technologies has proven to be expensive and more importantly, often damaging to the natural resource properties of the soil, sediment, or aquifer. phytoremediation is defined as the cleanup of contaminated sites using plants. there has been evidence of enhanced polycyclic aromatic hydrocarbons (pahs) degradation in rhizos ...200516151227
stomatal characteristics of riparian poplar species in a semi-arid environment.several native poplar species meet at the margins of their natural distributions in southern alberta, canada. in this semi-arid area, poplars are obligate riparian species but they occupy several intergrading ecoregions. populus deltoides bartr. ex marsh predominates in the warmest and driest eastern prairie ecoregions; p. balsamifera l. occupies the cooler and wetter western parkland and montane ecoregions; and p. angustifolia james and hybrids between the species occur in the intermediate gras ...200616356918
activation of stress-responsive mitogen-activated protein kinase pathways in hybrid poplar (populus trichocarpa x populus deltoides).plant mitogen-activated protein kinase (mapk) cascades are important amplifying modules that can rapidly transduce stress signals into various appropriate intracellular responses. several extracellular regulated kinase (erk)-type mapks involved in plant defense signaling have been identified in herbaceous species, but no mapk cascade has yet been characterized in a tree species. we examined the signal transduction events that lead to activation of defense mechanisms in poplar, a major forest spe ...200515631976
assessment of populus wood chemistry following the introduction of a bt toxin gene.unintended changes in plant physiology, anatomy and metabolism as a result of genetic engineering are a concern as more transgenic plants are commercially deployed in the ecosystem. we compared the cell wall chemical composition of three populus lines (populus trichocarpa torr. & a. gray x populus trichocarpa bartr. ex marsh., populus trichocarpa x populus nigra l. and populus deltoides x populus nigra) genetically modified to express the cry3a or cry3b2 protein of bacillus thuringiensis (bt) wi ...200616452069
[identification of markers linked to resistance locus of marssonina leaf spot in poplars by bulked segregant analysis(bsa)].dna markers linked to resistance locus of marssonina leaf spot in poplars were found by bulked segregant analysis(bsa). the bulks consisted of individual with a extreme phenotype taken from a population of 91 f1 clones,which is a progeny of populus deltoides bartr.cv."lux"(i-69/55)(resistance) and p.euramericana cv.i-45(susceptible). out of 114 rapd primers, four markers showed polymorphisms between the resistance-bulk and the susceptible-bulk.by using selective genotype linkage analysis,opai17- ...200216135446
methylobacterium populi sp. nov., a novel aerobic, pink-pigmented, facultatively methylotrophic, methane-utilizing bacterium isolated from poplar trees (populus deltoides x nigra dn34).a pink-pigmented, aerobic, facultatively methylotrophic bacterium, strain bj001t, was isolated from internal poplar tissues (populus deltoidesxnigra dn34) and identified as a member of the genus methylobacterium. phylogenetic analyses showed that strain bj001t is related to methylobacterium thiocyanatum, methylobacterium extorquens, methylobacterium zatmanii and methylobacterium rhodesianum. however, strain bj001t differed from these species in its carbon-source utilization pattern, particularly ...200415280290
hybrid poplar clones with populus maximowiczii parentage demonstrate postoviposition antibiosis to cryptorhynchus lapathi (coleoptera: curculionidae).damage caused by the poplar-and-willow borer, cryptorhynchus lapathi (l.) (coleoptera: curculionidae), is reported to vary among hybrid poplar clones. we evaluated oviposition preferences and larval success in four hybrid poplars on potted and field-planted trees. oviposition occurred somewhat less frequently and abundantly on two clones with populus maximowiczii henry parentage in field-planted and potted trees, and significantly fewer larvae survived to adulthood on those clones. no adults eme ...200516539157
the 32-kilodalton vegetative storage protein of salix microstachya turz : characterization and immunolocalization.a 32-kilodalton vegetative storage protein, found in salix microstachya turz. bark during the overwintering period, was purified and characterized using several polyacrylamide gel electrophoretic procedures. solubility characteristics and amino acid analyses were also performed. the protein is water soluble, is glycosylated, has no disulfide-bonded subunits, but is composed of a family of isoelectric isomers. the majority of these isomers are basic. characteristic of storage proteins, the protei ...199116668465
coupling two mercury resistance genes in eastern cottonwood enhances the processing of organomercury.eastern cottonwood (populus deltoides bartr. ex marsh.) trees were engineered to express mera (mercuric ion reductase) and merb (organomercury lyase) transgenes in order to be used for the phytoremediation of mercury-contaminated soils. earlier studies with arabidopsis thaliana and nicotiana tabacum showed that this gene combination resulted in more efficient detoxification of organomercurial compounds than did merb alone, but neither species is optimal for long-term field applications. leaf dis ...200717309680
transcript profiling of poplar leaves upon infection with compatible and incompatible strains of the foliar rust melampsora larici-populina.to understand key processes governing defense mechanisms in poplar (populus spp.) upon infection with the rust fungus melampsora larici-populina, we used combined histological and molecular techniques to describe the infection of populus trichocarpa x populus deltoides 'beaupré' leaves by compatible and incompatible fungal strains. striking differences in host-tissue infection were observed after 48-h postinoculation (hpi) between compatible and incompatible interactions. no reactive oxygen spec ...200717400708
stimulation and molecular characterization of bacterial perchlorate degradation by plant-produced electron donors.root homogenate from poplar trees (populus deltoides x nigra dn34, imperial carolina) stimulated perchlorate degradation in microcosms of soil and water samples collected at a perchlorate contaminated site, the longhorn army ammunition plant (lhaap), located outside karnack, texas. direct use of root products by perchlorate-degrading bacteria was shown for the first time as six pureculture bacteria isolated from lhaap perchlorate-degrading microcosms degraded perchlorate when given root products ...200616433366
soil metal concentrations and vegetative assemblage structure in an urban brownfield.anthropogenic sources of toxic elements have had serious ecological and human health impacts. analysis of the soil samples from a brownfield within liberty state park, jersey city, nj, usa, showed that arsenic, chromium, lead, zinc and vanadium exist at concentrations above those considered ambient for the area. accumulation and translocation features were characterized for the dominant plant species of four vegetative assemblages. the trees betula populifolia and populus deltoides were found to ...200817900771
functional analysis of the kunitz trypsin inhibitor family in poplar reveals biochemical diversity and multiplicity in defense against herbivores.we investigated the functional and biochemical variability of kunitz trypsin inhibitor (kti) genes of populus trichocarpa x populus deltoides. phylogenetic analysis, expressed sequence tag databases, and western-blot analysis confirmed that these genes belong to a large and diverse gene family with complex expression patterns. five wound- and herbivore-induced genes representing the diversity of the kti gene family were selected for functional analysis and shown to produce active kti proteins in ...200818024557
thermal acclimation of photosynthesis: a comparison of boreal and temperate tree species along a latitudinal transect.common gardens were established along a approximately 900 km latitudinal transect to examine factors limiting geographical distributions of boreal and temperate tree species in eastern north america. boreal representatives were trembling aspen (populus tremuloides michx.) and paper birch (betula papyrifera marsh.), while temperate species were eastern cottonwood (populus deltoides bartr ex. marsh var. deltoides) and sweetgum (liquidambar styraciflua l.). the species were compared with respect to ...201020082671
extensive allelic variation in gene expression in populus f1 hybrids.hybridization between plant species can induce speciation as well as phenotypic novelty and heterosis. hybrids also can show genome rearrangements and gene expression changes compared with their parents. here we determined the allelic variation in gene expression in populus trichocarpa x populus deltoides f(1) hybrids. among 30 genes analyzed in four independently formed hybrids, 17 showed >1.5-fold expression biases for one of the two alleles, and there was monoallelic expression of one gene. e ...200718073418
changes in composition, structure and aboveground biomass over seventy-six years (1930-2006) in the black rock forest, hudson highlands, southeastern new york state.we sought to quantify changes in tree species composition, forest structure and aboveground forest biomass (agb) over 76 years (1930-2006) in the deciduous black rock forest in southeastern new york, usa. we used data from periodic forest inventories, published floras and a set of eight long-term plots, along with species-specific allometric equations to estimate agb and carbon content. between the early 1930s and 2000, three species were extirpated from the forest (american elm (ulmus americana ...200818244941
vegetative buffers for fan emissions from poultry farms: 1. temperature and foliar nitrogen.this study sought to evaluate the potential of trees planted around commercial poultry farms to trap ammonia (nh(3)), the gas of greatest environmental concern to the poultry industry. four plant species (norway spruce, spike hybrid poplar, streamco willow, and hybrid willow) were planted on eight commercial farms from 2003 to 2004. because temperature (t) can be a stressor for trees, t was monitored in 2005 with data loggers among the trees in front of the exhaust fans (11.4 to 17.7 m) and at a ...200818246513
microgenomic analysis reveals cell type-specific gene expression patterns between ray and fusiform initials within the cambial meristem of populus.the vascular cambium is the meristem in trees that produce wood. this meristem consists of two types of neighbouring initials: fusiform cambial cells (fccs), which give rise to the axial cell system (i.e. fibres and vessel elements), and ray cambial cells (rccs), which give rise to rays. there is little molecular information on the mechanisms whereby the differing characteristics of these neighbouring cells are maintained. a microgenomic approach was adopted in which the transcriptomes of fccs a ...200818631289
microparticle collection and concentration via a miniature surface acoustic wave device.the ability to detect microbes, pollens and other microparticles is a critically important ability given the increasing risk of bioterrorism and emergence of antibiotic-resistant bacteria. the efficient collection of microparticles via a liquid water droplet moved by a surface acoustic wave (saw) device is demonstrated in this study. a fluidic track patterned on the saw device directs the water droplet's motion, and fluid streaming induced inside the droplet as it moves along is a key advantage ...200717476381
uptake of n-nitrosodimethylamine (ndma) from water by phreatophytes in the absence and presence of perchlorate as a co-contaminant.the uptake and fate of the emerging contaminants n-nitrosodimethylamine (ndma) and perchlorate in phreatophytes was studied in a hydroponics system under greenhouse conditions. ndma is a potent carcinogen, and perchlorate disrupts the functioning ofthe human thyroid gland. the rate of removal of ndma from solution by rooted cuttings of black willow (salix nigra) and hybrid poplar (populus deltoides x nigra, dn34) trees varied seasonally, with faster removal in summer months when transpiration ra ...200617180991
fine mapping and identification of nucleotide binding site/leucine-rich repeat sequences at the mer locus in populus deltoides 's9-2'.abstract melampsora larici-populina is the most damaging leaf pathogen for poplar in europe. previous genetic analyses have revealed both qualitative and quantitative resistance to this fungus. as a starting point for positional cloning of the gene or genes conferring qualitative resistance to m. larici-populina races e1, e2, and e3, a local genetic map of the melampsora resistance (mer) locus was constructed based on amplified fragment length polymorphism (aflp) markers. eleven aflp markers wer ...200118943442
genetic structure of mycosphaerella populorum (anamorph septoria musiva) populations in north-central and northeastern north america.abstract in order to characterize the genetic variation of the poplar pathogen mycosphaerella populorum (anamorph septoria musiva), we have studied seven north american populations using the polymerase chain reaction random amplified polymorphic dna (rapd) technique. the fungal populations were sampled in 2001 and 2002 by obtaining 352 isolates from cankers and leaf spots in hybrid poplar plantations and adjacent eastern cottonwood (populus deltoides). a total of 21 polymorphic rapd markers were ...200518943776
recessive resistance to septoria stem canker of hybrid poplar.abstract stem canker, caused by septoria musiva, is the most serious disease limiting intensive hybrid poplar culture in eastern north america. populus deltoides (d) is itself resistant, but the susceptibility of western black cottonwood, p. trichocarpa (t) is apparently dominant in the f(1) generation. to test a hypothesis of recessive inheritance of canker resistance, a three-generation t x d pedigree was deployed in the field in iowa and minnesota. in both sites and in keeping with expectatio ...200118943444
genome survey and characterization of endophytic bacteria exhibiting a beneficial effect on growth and development of poplar trees.the association of endophytic bacteria with their plant hosts has a beneficial effect for many different plant species. our goal is to identify endophytic bacteria that improve the biomass production and the carbon sequestration potential of poplar trees (populus spp.) when grown in marginal soil and to gain an insight in the mechanisms underlying plant growth promotion. members of the gammaproteobacteria dominated a collection of 78 bacterial endophytes isolated from poplar and willow trees. as ...200919060168
microbiology of wetwood: importance of pectin degradation and clostridium species in living trees.wetwood samples from standing trees of eastern cottonwood (populus deltoides), black poplar (populus nigra), and american elm (ulmus americana) contained high numbers of aerobic and anaerobic pectin-degrading bacteria (10 to 10 cells per g of wood). high activity of polygalacturonate lyase (</=0.5 u/ml) was also detected in the fetid liquid that spurted from wetwood zones in the lower trunk when the trees were bored. a prevalent pectin-degrading obligately anaerobic bacterium isolated from these ...198116345848
analysis of the poplar phloem proteome and its response to leaf wounding.phloem exudate collected from hybrid poplar (populus trichocarpa x populus deltoides) was estimated to have more than 100 proteins, of which 48 were identified using lc-ms/ms. comparative two-dimensional gel electrophoresis demonstrated that two phloem exudate proteins were significantly (p<0.05) upregulated 24 h after leaf wounding. these were identified as pop3/sp1 and a thaumatin-like protein. this is the first characterization of a phloem proteome from a tree species.200919245218
productivity, water-use efficiency and tolerance to moderate water deficit correlate in 33 poplar genotypes from a populus deltoides x populus trichocarpa f1 progeny.genotypic variability for productivity, water-use efficiency and leaf traits in 33 genotypes selected from an f1 progeny of populus deltoides bartr. ex marsh x populus trichocarpa l. was explored under optimal and moderate water-deficit conditions. saplings of the 33 genotypes were grown in a two-plot open field at inra orléans (france) and coppiced every year. a moderate water deficit was induced during two successive years on one plot by withholding irrigation, while the second one remained ir ...200919773340
repeated unidirectional introgression towards populus balsamifera in contact zones of exotic and native poplars.as the evolutionary significance of hybridization is largely dictated by its extent beyond the first generation, we broadly surveyed patterns of introgression across a sympatric zone of two native poplars (populus balsamifera, populus deltoides) in quebec, canada within which european exotic populus nigra and its hybrids have been extensively planted since the 1800s. single nucleotide polymorphisms (snps) that appeared fixed within each species were characterized by dna-sequencing pools of pure ...201020002578
populus deltoides roots harbor distinct microbial communities within the endosphere and rhizosphere across contrasting soil types.the root-rhizosphere interface of populus is the nexus of a variety of associations between bacteria, fungi and host plant and an ideal model for studying interactions between plants and microorganisms. however, such studies have generally been confined to greenhouse and plantation systems. here we analyze microbial communities from the root endophytic and rhizospheric habitats of p. deltoides, in mature natural trees from both upland and bottomland sites in central tennessee. community profilin ...201121764952
histological aspects of a hypersensitive response in poplar to melampsora larici-populina.abstract the course of the infection and development of the biotrophic fungus melampsora larici-populina on leaf tissue from the hybrid poplar populus deltoides x p. nigra 'ogy' was monitored at the histological level. leaf disks were inoculated with one of two rust physiological races (e1 and e2), resulting in interactions that were either incompatible (race e1) or compatible (race e2). in the compatible interaction, the fungus rapidly colonized the leaf without inducing any apparent host respo ...199918944764
components acting downstream of short day perception regulate differential cessation of cambial activity and associated responses in early and late clones of hybrid poplar.short days (sds) in autumn induce growth cessation, bud set, cold acclimation, and dormancy in trees of boreal and temperate forests, and these responses occur earlier in northern than in southern genotypes. nevertheless, we know little about whether this variation results from differential perception of sds or differential downstream responses to the sd signal or a combination of the two. we compared global patterns of sd-regulated gene expression in the stems of hybrid poplar (populus trichoca ...201020847139
effect of poplar genotypes on mycorrhizal infection and secreted enzyme activities in mycorrhizal and non-mycorrhizal roots.the impact of ectomycorrhiza formation on the secretion of exoenzymes by the host plant and the symbiont is unknown. thirty-eight f(1) individuals from an interspecific populus deltoides (bartr.)×populus trichocarpa (torr. & a. gray) controlled cross were inoculated with the ectomycorrhizal fungus laccaria bicolor. the colonization of poplar roots by l. bicolor dramatically modified their ability to secrete enzymes involved in organic matter breakdown or organic phosphorus mobilization, such as ...201020881013
molecular characterization of flavonol synthase from poplar and its application to the synthesis of 3-o-methylkaempferol.biosynthesis of flavonoid derivatives requires enzyme(s) having high reactivity as well as regioselectivity. we have synthesized 3-o-kaempferol from naringenin using two enzymes. the first reaction, in which naringenin is converted to kaempferol, is mediated by flavonol synthase (fls). an fls (pfls) with strong catalytic activity was cloned and characterized from the genome sequence of the poplar (populus deltoides). pfls consists of a 1,008 bp orf encoding a 38 kda protein. pfls was expressed i ...201020033832
habituation to thaxtomin a in hybrid poplar cell suspensions provides enhanced and durable resistance to inhibitors of cellulose synthesis.thaxtomin a (ta), a phytotoxin produced by the phytopathogen streptomyces scabies, is essential for the development of potato common scab disease. ta inhibits cellulose synthesis but its actual mode of action is unknown. addition of ta to hybrid poplar (populus trichocarpa x populus deltoides) cell suspensions can activate a cellular program leading to cell death. in contrast, it is possible to habituate hybrid poplar cell cultures to grow in the presence of ta levels that would normally induce ...201021143977
antimicrobial flavonoids from the twigs of populus nigra × populus deltoides.a bioassay-guided fractionation of the ethyl acetate extract from the twigs of the hybrid poplar 'neva', populus nigra l. × populus deltoides marsh, led to the isolation of three flavonoids, which were identified by means of spectrometric and physicochemical analysis as 5-hydroxy-7-methoxy-flavone (1), 5,7-dihydoxy-flavone (2) and 5,7-dihydroxy-flavonol (3). these compounds were further screened for their antimicrobial activity against plant pathogens, including three bacteria (pseudomonas lachr ...201121416454
characterization of two major genetic factors controlling quantitative resistance to melampsora larici-populina leaf rust in hybrid poplars: strain specificity, field expression, combined effects, and relationship with a defeated qualitative resistance gene.abstract two genetic factors explain a significant proportion of the variability for quantitative resistance to melampsora larici-populina leaf rust in a populus deltoides x p. trichocarpa f(1) progeny. one is inherited from p. deltoides and is associated with a defeated qualitative resistance gene r(1), and the other, r(us), is inherited from p. trichocarpa. to assess the potential contribution of these two factors for durable resistance breeding, 284 genotypes from this f(1) progeny were studi ...200418943707
leaf respiratory acclimation to climate: comparisons among boreal and temperate tree species along a latitudinal transect.in common gardens along an ∼900 km latitudinal transect through wisconsin and illinois, u.s.a., tree species typical of boreal and temperate forests were compared with respect to the nature and magnitude of leaf respiratory acclimation to contrasting climates. the boreal representatives were trembling aspen (populus tremuloides michx.) and paper birch (betula papyrifera marsh.), while the temperate species were eastern cottonwood (populus deltoides bartr ex. marsh var. deltoides) and sweetgum (l ...201121990024
Developing a sustainable phytomanagement strategy for excessive selenium in western United States and India.Phytomanagement technology is recognized as an inexpensive and environmental friendly strategy for managing natural-occurring selenium (Se) in soils and in poor quality waters. Multi-year field and greenhouse studies were conducted with different plant species in California, USA and Punjab, India under high Se growing conditions. Some of the plant species included; canola (Brassica napus), mustard (B. juncea), broccoli (B. oleracea), spearmint (Mentha viridis), sugarcane (Saccharum officcinarum) ...201122046761
[Effects of cadmium stress on the microbial biodiversity in purple soil and alluvial soil potted with a poplar (Populus deltoides x Populus nigra)].Effects of current Cd contamination levels on microbial biodiversity were studied under the typical Cd contaminated soils in the Yangtze Basin. Purple soil and alluvial soil potted with a poplar (Populus deltoides x Populus nigra) were selected, and the culturable soil microbial amounts by flat method, microbial biomass and bacterial community structure by PCR-DGGE were investigated. Cd supplies significantly increased the culturable amounts of bacteria and actinomyces in purple soil, but decrea ...201121922843
maturation stress generation in poplar tension wood studied by synchrotron radiation microdiffraction.tension wood is widespread in the organs of woody plants. during its formation, it generates a large tensile mechanical stress called maturation stress. maturation stress performs essential biomechanical functions such as optimizing the mechanical resistance of the stem, performing adaptive movements, and ensuring the long-term stability of growing plants. although various hypotheses have recently been proposed, the mechanism generating maturation stress is not yet fully understood. in order to ...201021068364
effect of applying an arsenic-resistant and plant growth-promoting rhizobacterium to enhance soil arsenic phytoremediation by populus deltoides lh05-17.bioremediation of highly arsenic (as)-contaminated soil is difficult because as is very toxic for plants and micro-organisms. the aim of this study was to investigate soil arsenic removal effects using poplar in combination with the inoculation of a plant growth-promoting rhizobacterium (pgpr).201121895895
luxr- and luxi-type quorum-sensing circuits are prevalent in members of the populus deltoides microbiome.we are interested in the root microbiome of the fast-growing eastern cottonwood tree, populus deltoides. there is a large bank of bacterial isolates from p. deltoides, and there are 44 draft genomes of bacterial endophyte and rhizosphere isolates. as a first step in efforts to understand the roles of bacterial communication and plant-bacterial signaling in p. deltoides, we focused on the prevalence of acyl-homoserine lactone (ahl) quorum-sensing-signal production and reception in members of the ...201323851092
newly identified helper bacteria stimulate ectomycorrhizal formation in populus.mycorrhiza helper bacteria (mhb) are known to increase host root colonization by mycorrhizal fungi but the molecular mechanisms and potential tripartite interactions are poorly understood. through an effort to study populus microbiome, we isolated 21 pseudomonas strains from native populus deltoides roots. these bacterial isolates were characterized and screened for mhb effectiveness on the populus-laccaria system. two additional pseudomonas strains (i.e., pf-5 and bbc6r8) from existing collecti ...201425386184
diversity of pseudomonas genomes, including populus-associated isolates, as revealed by comparative genome analysis.the pseudomonas genus contains a metabolically versatile group of organisms that are known to occupy numerous ecological niches, including the rhizosphere and endosphere of many plants. their diversity influences the phylogenetic diversity and heterogeneity of these communities. on the basis of average amino acid identity, comparative genome analysis of >1,000 pseudomonas genomes, including 21 pseudomonas strains isolated from the roots of native populus deltoides (eastern cottonwood) trees resu ...201526519390
maturation stress generation in poplar tension wood studied by synchrotron radiation microdiffraction.tension wood is widespread in the organs of woody plants. during its formation, it generates a large tensile mechanical stress, called maturation stress. maturation stress performs essential biomechanical functions such as optimizing the mechanical resistance of the stem, performing adaptive movements, and ensuring long-term stability of growing plants. although various hypotheses have recently been proposed, the mechanism generating maturation stress is not yet fully understood. in order to dis ...201020071605
biodegradation of naphthalene and anthracene by chemo-tactically active rhizobacteria of populus deltoides.several naphthalene and anthracene degrading bacteria were isolated from rhizosphere of populus deltoides, which were growing in non-contaminated soil. among these, four isolates, i.e. kurthia sp., micrococcus varians, deinococcus radiodurans and bacillus circulans utilized chrysene, benzene, toluene and xylene, in addition to anthracene and naphthalene. kurthia sp and b. circulans showed positive chemotactic response for naphthalene and anthracene. the mean growth rate constant (k) of isolates ...201024031572
defining hybrid poplar (populus deltoides x populus trichocarpa) tolerance to ozone: identifying key parameters.this study examined whether two genotypes of hybrid poplar (populus deltoides x populus trichocarpa), previously classified as ozone tolerant and ozone sensitive, had differing physiological and biochemical responses when fumigated with 120 nl l(-1) ozone for 6 h per day for eight consecutive days. isoprene emission rate, ozone uptake and a number of physiological and biochemical parameters were investigated before, during and after fumigation with ozone. previous studies have shown that isopren ...200919076530
hydroxylated metabolites of 4-monochlorobiphenyl and its metabolic pathway in whole poplar plants.4-monochlorobiphenyl (cb3), mainly an airborne pollutant, undergoes rapid biotransformation to produce hydroxylated metabolites (oh-cb3s). however, up to now, hydroxylation of cb3 has not been studied in living organisms. in order to explore the formation of hydroxylated metabolites of cb3 in whole plants, poplars (populus deltoides x nigra, dn34) were exposed to cb3 for 10 days. poplars are a model plant with complete genomic sequence, and they are widely used in phytoremediation. results showe ...201020402517
partial resistance to melampsora larici-populina leaf rust in hybrid poplars: genetic variability in inoculated excised leaf disk bioassay and relationship with complete resistance.abstract inoculated excised leaf disk technique allows decomposition of poplar partial resistance to melampsora larici-populina leaf rust into key epidemiological components such as latent period (lp), uredinia number (un), uredinia size (us), and spore production (sp) for a given m. larici-populina strain under controlled environmental conditions. three hundred thirty-six genotypes from an interspecific populus deltoides x p. trichocarpa f(1) progeny segregating for complete resistance to m. la ...200318944356
a carotenoid-deficient mutant in pantoea sp. yr343, a bacteria isolated from the rhizosphere of populus deltoides, is defective in root colonization.the complex interactions between plants and their microbiome can have a profound effect on the health and productivity of the plant host. a better understanding of the microbial mechanisms that promote plant health and stress tolerance will enable strategies for improving the productivity of economically important plants. pantoea sp. yr343 is a motile, rod-shaped bacterium isolated from the roots of populus deltoides that possesses the ability to solubilize phosphate and produce the phytohormone ...201627148182
poplar pdc3h17 and pdc3h18 are direct targets of pdmyb3 and pdmyb21, and positively regulate secondary wall formation in arabidopsis and poplar.wood biomass is mainly made of secondary cell walls, whose formation is controlled by a multilevel network. the tandem ccch zinc finger (tzf) proteins involved in plant secondary wall formation are poorly understood. two tzf genes, pdc3h17 and pdc3h18, were isolated from populus deltoides and functionally characterized in escherichia coli, tobacco, arabidopsis and poplar. pdc3h17 and pdc3h18 are predominantly expressed in cells of developing wood, and the proteins they encode are targeted to cyt ...201424786865
metabolomics reveals the origins of antimicrobial plant resins collected by honey bees.the deposition of antimicrobial plant resins in honey bee, apis mellifera, nests has important physiological benefits. resin foraging is difficult to approach experimentally because resin composition is highly variable among and between plant families, the environmental and plant-genotypic effects on resins are unknown, and resin foragers are relatively rare and often forage in unobservable tree canopies. subsequently, little is known about the botanical origins of resins in many regions or the ...201324204850
qtls for woolly poplar aphid (phloeomyzus passerinii l.) resistance detected in an inter-specific populus deltoides x p. nigra mapping population.the genus populus represents one of the most economically important groups of forest trees. it is composed by approximately 30 species used for wood and non-wood products, phytoremediation and biomass. poplar is subjected to several biological and environmental threats although, compared to annual crops, we know far less about the genetic bases of biotic stress resistance. woolly poplar aphid (phloeomyzus passerinii) is considered a main pest of cultivated poplars in european and american countr ...201627022954
metabolic functions of pseudomonas fluorescens strains from populus deltoides depend on rhizosphere or endosphere isolation compartment.the bacterial microbiota of plants is diverse, with 1000s of operational taxonomic units (otus) associated with any individual plant. in this work, we used phenotypic analysis, comparative genomics, and metabolic models to investigate the differences between 19 sequenced pseudomonas fluorescens strains. these isolates represent a single otu and were collected from the rhizosphere and endosphere of populus deltoides. while no traits were exclusive to either endosphere or rhizosphere p. fluorescen ...201526528266
a luxr homolog in a cottonwood tree endophyte that activates gene expression in response to a plant signal or specific peptides.homologs of the luxr acyl-homoserine lactone (ahl) quorum-sensing signal receptor are prevalent in proteobacteria isolated from roots of the eastern cottonwood tree, populus deltoides many of these isolates possess an orphan luxr homolog, closely related to oryr from the rice pathogen xanthomonas oryzae oryr does not respond to ahl signals but, instead, responds to an unknown plant compound. we discovered an oryr homolog, pipr, in the cottonwood endophyte pseudomonas sp. strain gm79. the genes a ...201627486195
two poplar-associated bacterial isolates induce additive favorable responses in a constructed plant-microbiome system.the biological function of the plant-microbiome system is the result of contributions from the host plant and microbiome members. the populus root microbiome is a diverse community that has high abundance of β- and γ-proteobacteria, both classes which include multiple plant-growth promoting representatives. to understand the contribution of individual microbiome members in a community, we studied the function of a simplified community consisting of pseudomonas and burkholderia bacterial strains ...201627200001
dibenzo-α-pyrones: a new class of larvicidal metabolites against aedes aegypti from the endophytic fungus hyalodendriella sp. ponipodef12.in our search for new agrochemicals from endophytic fungi, the crude extract of the endophytic hyalodendriella sp. ponipodef12 associated with the hybrid 'neva' of populus deltoides marsh × p. nigra l. was found to possess larvicidal activity against aedes aegypti.201627862895
bulked segregant analysis identifies molecular markers linked to melampsora medusae resistance in populus deltoides.abstract in the north central united states, leaf rust caused by melampsora medusae is a major disease problem on populus deltoides. in this study we identified molecular markers linked to a m. medusae resistance locus (lrd1) that was segregating 1:1 within an intraspecific p. deltoides family (c9425dd). previous field results were confirmed in the controlled environment of a growth chamber through an excised whole-leaf inoculation method. using bulked segregant analysis we identified two random ...200018944531
optimization of a real-time pcr assay for the detection of the quarantine pathogen melampsora medusae f. sp. deltoidae.melampsora medusae (mm), one of the causal agents of poplar rust, is classified as an a2 quarantine pest for european plant protection organization (eppo) and its presence in europe is strictly controlled. two formae speciales have been described within mm, melampsora medusae f. sp. deltoidae (mmd), and melampsora medusae f. sp. tremuloidae (mmt) on the basis of their pathogenicity on populus species from the section aigeiros (e.g. populus deltoides) or populus (e.g. populus tremuloides), respec ...201323809649
seasonal changes between one- and two-phasic response of plant leaves to heat stress.plant leaves normally respond to increasing injurious temperatures with a more or less continuous increase of tissue damage. a discontinuous response comprising a first lethal or sublethal temperature range which is followed by a non-injurious temperature range and a second, the lethal temperature range appeared to be an exception. the data with populus deltoides x simonii show that a two-phasic response is most pronounced after heat shocks of 15 s and was no longer detected after exposure to he ...197728309148
an essential role of caffeoyl shikimate esterase in monolignol biosynthesis in medicago truncatula.biochemical and genetic analyses have previously identified caffeoyl shikimate esterase (cse) as an enzyme in the monolignol biosynthesis pathway in arabidopsis thaliana, although the generality of this finding has been questioned. here we show the presence of cse genes and associated enzyme activity in barrel medic (medicago truncatula, dicot, leguminosae), poplar (populus deltoides, dicot, salicaceae), and switchgrass (panicum virgatum, monocot, poaceae). loss of function of cse in transposon ...201627037613
poplar ft2 shortens the juvenile phase and promotes seasonal flowering.many woody perennials, such as poplar (populus deltoides), are not able to form flower buds during the first several years of their life cycle. they must undergo a transition from the juvenile phase to the reproductive phase to be competent to produce flower buds. after this transition, trees begin to form flower buds in the spring of each growing season. the genetic factors that control flower initiation, ending the juvenile phase, are unknown in poplar. the factors that regulate seasonal flowe ...200616844908
komagataella populi sp. nov. and komagataella ulmi sp. nov., two new methanol assimilating yeasts from exudates of deciduous trees.two new species of the methanol assimilating ascosporic yeast genus komagataella are described. komagataella populi sp. nov. (nrrl yb-455, cbs 12362, type strain, mycobank accession number = 564110) was isolated from an exudate on a cottonwood tree (populus deltoides), peoria, illinois, usa, and komagataella ulmi sp. nov. (nrrl yb-407, cbs 12361, type strain, mycobank accession number = 564111) was isolated from the exudate on an elm tree (ulmus americana), also growing in peoria, illinois. the ...201222302468
arabidopsis eif5a3 influences growth and the response to osmotic and nutrient stress.ateif5a3, one of three genes encoding eukaryotic translation initiation factor 5a (eif5a) in arabidopsis thaliana, and corresponding genes pdeif5a3 from populus deltoides (eastern cottonwood) and sleif5a4 from solanum lycopersicum (tomato) were constitutively over-expressed in a. thaliana. the resultant transgenic plants exhibited enhanced vegetative and reproductive growth. indeed, the increase in seed yield relative to empty vector controls for the pdeif5a3 over-expressing plants ranged from 5 ...201020492553
analysis of gene expression in poplar trees (populus deltoides x nigra, dn34) exposed to the toxic explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (rdx).poplar plants (populus deltoides x nigra, dn34) growing under hydroponic conditions were exposed to 50 mg l(-1) of hexahydro-1,3,5-trinitro-1,3,5-triazine (rdx) for 24 h. the expression of genes potentially involved in the metabolism of toxic explosives was analyzed by reverse-transcriptase (rt) real-time pcr. genes under study were selected by reference to corresponding genes that were previously shown to be upregulated in the model plant arabidopsis thaliana by exposure to 2,4,6-trinitrotoluen ...201218246712
phytostimulation of poplars and arabidopsis exposed to silver nanoparticles and ag⁺ at sublethal concentrations.the increasing likelihood of silver nanoparticle (agnp) releases to the environment highlights the importance of understanding agnp interactions with plants, which are cornerstones of most ecosystems. in this study, poplars (populus deltoides × nigra) and arabidopsis thaliana were exposed hydroponically to nanoparticles of different sizes (peg-coated 5 and 10 nm agnps, and carbon-coated 25 nm agnps) or silver ions (ag(+), added as agno₃) at a wide range of concentrations (0.01 to 100 mg/l). wher ...201323631766
host selection and probing behavior of the poplar aphid chaitophorus leucomelas (sternorrhyncha: aphididae) on two poplar hybrids with contrasting susceptibility to aphids.poplars are frequently attacked by aphids. the differential susceptibility of poplar hybrids to the aphid chaitophorus leucomelas koch (sternorrhyncha: aphididae) has been described, but the mechanism underlying this pattern is unknown. this work tested the hypothesis that poplar resistance to this aphid is associated with the presence of volatiles and secondary plant compounds that affect host selection and feeding behavior. this hypothesis was tested by studying the host choice and feeding beh ...201424665710
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