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Sample records for poplar ring-h2 protein

  1. Does PtaRHE1, a poplar RING-H2 protein, play a role in water conduction through ABA signaling?

    PubMed Central

    Moussawi, Jihad; Baldacci-Cresp, Fabien; El Jaziri, Mondher; Baucher, Marie

    2014-01-01

    RING (REALLY INTERESTING NEW GENE) proteins with E3 ligase activity are largely represented in plants. They have been shown to play important roles in the regulation of many biological processes by recognizing target proteins for ubiquitination. PtaRHE1, encoding a poplar RING-H2 domain-containing protein with E3 ligase activity has been previously shown to be expressed during the establishment of secondary vascular system in poplar. In the present report, we demonstrate that the expression of PtaRHE1 and the accumulation of its corresponding protein are modulated by the relative atmospheric and soil humidity and by abscisic acid. Overall, the integrated data are discussed within a working model highlighting a plausible function of PtaRHE1 in the signaling and/or in the regulation of water status in poplar. PMID:24393707

  2. Ectopic expression of PtaRHE1, encoding a poplar RING-H2 protein with E3 ligase activity, alters plant development and induces defence-related responses

    PubMed Central

    Mukoko Bopopi, Johnny; Vandeputte, Olivier M.; Himanen, Kristiina; Mol, Adeline; Vaessen, Quentin; El Jaziri, Mondher; Baucher, Marie

    2010-01-01

    RING (really interesting new gene)-H2 domain-containing proteins are widely represented in plants and play important roles in the regulation of many developmental processes as well as in plant–environment interactions. In the present report, experiments were performed to unravel the role of the poplar gene PtaRHE1, coding for a RING-H2 protein. In vitro ubiquitination assays indicate a functional E3 ligase activity for PtaRHE1 with the specific E2 ubiquitin-conjugating enzyme UbcH5a. The overexpression of PtaRHE1 in tobacco resulted in a pleiotropic phenotype characterized by a curling of the leaves, the formation of necrotic lesions on leaf blades, growth retardation, and a delay in floral transition. The plant gene expression response to PtaRHE1 overexpression provided evidence for the up-regulation of defence- and/or programmed cell death-related genes. Moreover, genes coding for WRKY transcription factors as well as for mitogen-activated protein kinases, such as wound-induced protein kinase (WIPK), were also found to be induced in the transgenic lines as compared with the wild type. In addition, histochemical β-glucuronidase staining showed that the PtaRHE1 promoter is induced by plant pathogens and by elicitors such as salicylic acid and cellulase. Taken together, these results suggest that the E3 ligase PtaRHE1 plays a role in the ubiquitination-mediated regulation of defence response, possibly by acting upstream of WIPK and/or in the activation of WRKY factors. PMID:19892745

  3. Goliath, a ring-H2 mitochondrial protein, regulated by luteinizing hormone/human chorionic gonadotropin in rat leydig cells.

    PubMed

    Guais, A; Solhonne, B; Melaine, N; Guellaen, G; Bulle, F

    2004-01-01

    We have cloned the rat homologue of the ring-H2 protein Goliath involved in Drosophila development. The rat Goliath mRNA (1.85 kb) was translated as a major ubiquitous protein species of 28-kDa and three larger isoforms (50, 46, and 36 kDa) expressed mainly in liver, lung, stomach, heart, and thymus and barely detectable in other tissues (kidney, skeletal muscle, brain, testis, intestine, and spleen). By immunohistochemistry on rat testis sections, we localized the protein in interstitial tissue and seminiferous tubules. In tubules, Goliath was expressed mainly in postmeiotic germ cells and to a much lesser extent in Sertoli cells. In the interstitium, Goliath was exclusively present in Leydig cells. Using a series of immunolabeling, cellular fractionation, and electron microscopy experiments, we established that Goliath is present in mitochondria of the R2C Leydig cell line. Using short-term hypophysectomized animals, we showed that Goliath is regulated by LH/hCG in Leydig cells but not in germ cells. This regulation in Leydig cells concerned only the 50-kDa isoform. This report is the first description of a differential regulation of the Goliath protein between germ cells and Leydig cells.

  4. PtaRHE1, a Populus tremula × Populus alba RING-H2 protein of the ATL family, has a regulatory role in secondary phloem fibre development.

    PubMed

    Baldacci-Cresp, Fabien; Moussawi, Jihad; Leplé, Jean-Charles; Van Acker, Rebecca; Kohler, Annegret; Candiracci, Julie; Twyffels, Laure; Spokevicius, Antanas V; Bossinger, Gerd; Laurans, Françoise; Brunel, Nicole; Vermeersch, Marjorie; Boerjan, Wout; El Jaziri, Mondher; Baucher, Marie

    2015-06-01

    REALLY INTERESTING NEW GENE (RING) proteins play important roles in the regulation of many processes by recognizing target proteins for ubiquitination. Previously, we have shown that the expression of PtaRHE1, encoding a Populus tremula × Populus alba RING-H2 protein with E3 ubiquitin ligase activity, is associated with tissues undergoing secondary growth. To further elucidate the role of PtaRHE1 in vascular tissues, we have undertaken a reverse genetic analysis in poplar. Within stem secondary vascular tissues, PtaRHE1 and its corresponding protein are expressed predominantly in the phloem. The downregulation of PtaRHE1 in poplar by artificial miRNA triggers alterations in phloem fibre patterning, characterized by an increased portion of secondary phloem fibres that have a reduced cell wall thickness and a change in lignin composition, with lower levels of syringyl units as compared with wild-type plants. Following an RNA-seq analysis, a biological network involving hormone stress signalling, as well as developmental processes, could be delineated. Several candidate genes possibly associated with the altered phloem fibre phenotype observed in amiRPtaRHE1 poplar were identified. Altogether, our data suggest a regulatory role for PtaRHE1 in secondary phloem fibre development.

  5. An ATL78-Like RING-H2 Finger Protein Confers Abiotic Stress Tolerance through Interacting with RAV2 and CSN5B in Tomato

    PubMed Central

    Song, Jianwen; Xing, Yali; Munir, Shoaib; Yu, Chuying; Song, Lulu; Li, Hanxia; Wang, Taotao; Ye, Zhibiao

    2016-01-01

    RING finger proteins play an important role in plant adaptation to abiotic stresses. In the present study, a wild tomato (Solanum habrochaites) cold-induced RING-H2 finger gene, ShATL78L, was isolated, which has been identified as an abiotic stress responsive gene in tomato. The results showed that ShATL78L was constitutively expressed in various tissues such as root, leaf, petiole, stem, flower, and fruit. Cold stress up-regulated ShATL78L in the cold-tolerant S. habrochaites compared to the susceptible cultivated tomato (S. lycopersicum). Furthermore, ShATL78L expression was also regulated under different stresses such as drought, salt, heat, wound, osmotic stress, and exogenous hormones. Functional characterization showed that cultivated tomato overexpressing ShATL78L had improved tolerance to cold, drought and oxidative stresses compared to the wild-type and the knockdown lines. To understand the underlying molecular mechanism of ShATL78L regulating abiotic stress responses, we performed yeast one-hybrid and two-hybrid assays and found that RAV2 could bind to the promoter of ShATL78L and activates/alters its transcription, and CSN5B could interact with ShATL78L to regulate abiotic stress responses. Taken together, these results show that ShATL78L plays an important role in regulating plant adaptation to abiotic stresses through bound by RAV2 and interacting with CSN5B. Highlight: RAV2 binds to the promoter of ShATL78L to activates/alters its transcription to adapt the environmental conditions; furthermore, ShATL78L interacts with CSN5B to regulate the stress tolerance. PMID:27621744

  6. Investigating the Role of Extensin Proteins in Poplar Biomass Recalcitrance

    SciTech Connect

    Fleming, Margaret Brigham; Decker, Stephen R.; Bedinger, Patricia A.

    2016-04-13

    The biological conversion of cellulosic biomass to biofuel is hindered by cell wall recalcitrance, which can limit the ability of cellulases to access and break down cellulose. The purpose of this study was to investigate whether hydroxyproline-rich cell wall proteins (extensins) are present in poplar stem biomass, and whether these proteins may contribute to recalcitrance. Three classical extensin genes were identified in Populus trichocarpa through bioinformatic analysis of poplar genome sequences, with the following proposed names: PtEXTENSIN1 (Potri.001G019700); PtEXTENSIN2 (Potri.001G020100); PtEXTENSIN3 (Potri.018G050100). Tissue print immunoblots localized the extensin proteins in poplar stems to regions near the vascular cambium. Different thermochemical pretreatments reduced but did not eliminate hydroxyproline (Hyp, a proxy for extensins) from the biomass. Protease treatment of liquid hot water-pretreated poplar biomass reduced Hyp content by a further 16% and increased subsequent glucose yield by 20%. These data suggest that extensins may contribute to recalcitrance in pretreated poplar biomass, and that incorporating protease treatment into pretreatment protocols could result in a small but significant increase in the yield of fermentable glucose.

  7. Praja1, a novel gene encoding a RING-H2 motif in mouse development.

    PubMed

    Mishra, L; Tully, R E; Monga, S P; Yu, P; Cai, T; Makalowski, W; Mezey, E; Pavan, W J; Mishra, B

    1997-11-06

    As part of a cloning strategy to identify genes involved in early mouse liver development we have isolated Praja1, a gene with similar sequences to the Drosophila melanogaster gene goliath (gl) which is involved in the fate of mesodermal cells ultimately forming gut musculatures, fat body, and the heart. Praja1 is a 2.1 kb gene encoding a putative 396 amino acid ORF and includes a COOH-terminal RING-H2 domain. Using the Jackson Laboratory BSS panel, we have localized Praja1 on chromosome X at 36 cM, which may be a candidate gene for mouse sla (sex linked sideroblastic anemia), near the X inactivation center gene, Xist. Northern blot analysis demonstrated three transcripts (3.1, 2.6 and 2.1 kb) in mRNA from adult mouse tissues brain, liver, and kidney as well as in mRNA from developing mouse embryos (days 7, 11, 15 and 17 post coitus, p.c.). In vitro transcription/translation yielded a product with an Mr of 59 kD. Immunohistochemical staining of in vitro liver explant cultures using a heterologous antibody against praja1 demonstrated cytoplasmic staining of cuboidal cells that have hepatocyte morphology and organization. The presence of the RING-H2 domain, a proline-rich region at the COOH-end, and regions rich in acidic amino acids, leads to the hypothesis that the Praja1 product is possibly involved in mediating protein-protein interactions, possibly as part of a protein sorting or transport pathway. This is strengthened by the similarity of Praja1 to rat Neurodap1, whose product has been shown to localize to the endoplasmic reticulum and golgi in brain.

  8. The prolific ATL family of RING-H2 ubiquitin ligases.

    PubMed

    Guzmán, Plinio

    2012-08-01

    An abundant class of E3 ubiquitin ligases encodes the RING-finger domain. The RING finger binds to the E2 ubiquitin-conjugating enzyme and brings together both the E2 and substrate. It is predicted that 477 RING finger E3 ligases exist in Arabidopsis thaliana. A particular family among them, named Arabidopsis Tóxicos en Levadura (ATL), consists of 91 members that contain the RING-H2 variation and a hydrophobic domain located at the N-terminal end. Transmembrane E3 ligases are important in several biological processes. For instance, some transmembrane RING finger E3 ligases are main participants in the endoplasmic reticulum-associated degradation pathway that targets misfolded proteins. Functional analysis of a number of ATLs has shown that some of them regulate distinct pathways in plants. Several ATLs have been shown to participate in defense responses, while others play a role in the regulation of the carbon/nitrogen response during post-germinative seedling growth transition, in the regulation of cell death during root development, in endosperm development, or in the transition to flowering under short day conditions. The ATL family has also been instrumental in evolution studies for showing how gene families are expanded in plant genomes.

  9. The prolific ATL family of RING-H2 ubiquitin ligases

    PubMed Central

    Guzmán, Plinio

    2012-01-01

    An abundant class of E3 ubiquitin ligases encodes the RING-finger domain. The RING finger binds to the E2 ubiquitin-conjugating enzyme and brings together both the E2 and substrate. It is predicted that 477 RING finger E3 ligases exist in Arabidopsis thaliana. A particular family among them, named Arabidopsis Tóxicos en Levadura (ATL), consists of 91 members that contain the RING-H2 variation and a hydrophobic domain located at the N-terminal end. Transmembrane E3 ligases are important in several biological processes. For instance, some transmembrane RING finger E3 ligases are main participants in the endoplasmic reticulum-associated degradation pathway that targets misfolded proteins. Functional analysis of a number of ATLs has shown that some of them regulate distinct pathways in plants. Several ATLs have been shown to participate in defense responses, while others play a role in the regulation of the carbon/nitrogen response during post-germinative seedling growth transition, in the regulation of cell death during root development, in endosperm development, or in the transition to flowering under short day conditions. The ATL family has also been instrumental in evolution studies for showing how gene families are expanded in plant genomes. PMID:22827943

  10. A NAC domain protein family contributing to the regulation of wood formation in poplar.

    PubMed

    Ohtani, Misato; Nishikubo, Nobuyuki; Xu, Bo; Yamaguchi, Masatoshi; Mitsuda, Nobutaka; Goué, Nadia; Shi, Fusun; Ohme-Takagi, Masaru; Demura, Taku

    2011-08-01

    Wood harvested from trees is one of the most widely utilized natural materials on our planet. Recent environmental issues have prompted an increase in the demand for wood, especially as a cost-effective and renewable resource for industry and energy, so it is important to understand the process of wood formation. In the present study, we focused on poplar (Populus trichocarpa) NAC domain protein genes which are homologous to well-known Arabidopsis transcription factors regulating the differentiation of xylem vessels and fiber cells. From phylogenetic analysis, we isolated 16 poplar NAC domain protein genes, and named them PtVNS (VND-, NST/SND- and SMB-related proteins) genes. Expression analysis revealed that 12 PtVNS (also called PtrWND) genes including both VND and NST groups were expressed in developing xylem tissue and phloem fiber, whereas in primary xylem vessels, only PtVNS/PtrWND genes of the VND group were expressed. By using the post-translational induction system of Arabidopsis VND7, a master regulator of xylem vessel element differentiation, many poplar genes functioning in xylem vessel differentiation downstream from NAC domain protein genes were identified. Transient expression assays showed the variation in PtVNS/PtrWND transactivation activity toward downstream genes, even between duplicate gene pairs. Furthermore, overexpression of PtVNS/PtrWND genes induced ectopic secondary wall thickening in poplar leaves as well as in Arabidopsis seedlings with different levels of induction efficiency according to the gene. These results suggest that wood formation in poplar is regulated by cooperative functions of the NAC domain proteins.

  11. Engineering functional artificial hybrid proteins between poplar peroxiredoxin II and glutaredoxin or thioredoxin

    SciTech Connect

    Rouhier, Nicolas . E-mail: nrouhier@scbiol.uhp-nancy.fr; Gama, Filipe; Wingsle, Gunnar; Gelhaye, Eric; Gans, Pierre; Jacquot, Jean-Pierre

    2006-03-24

    The existence of natural peroxiredoxin-glutaredoxin hybrid enzymes in several bacteria is in line with previous findings indicating that poplar peroxiredoxin II can use glutaredoxin as an electron donor. This peroxiredoxin remains however unique since it also uses thioredoxin with a quite good efficiency. Based on the existing fusions, we have created artificial enzymes containing a poplar peroxiredoxin module linked to glutaredoxin or thioredoxin modules. The recombinant fusion enzymes folded properly into non-covalently bound homodimers or homotetramers. Two of the three protein constructs exhibit peroxidase activity, a reaction where the two modules need to function together, but they also display enzymatic activities specific of each module. In addition, mass spectrometry analyses indicate that the Prx module can be both glutathiolated or overoxidized in vitro. This is discussed in the light of the Prx reactivity.

  12. Genome-wide analysis of eukaryote thaumatin-like proteins (TLPs) with an emphasis on poplar

    PubMed Central

    2011-01-01

    Background Plant inducible immunity includes the accumulation of a set of defense proteins during infection called pathogenesis-related (PR) proteins, which are grouped into families termed PR-1 to PR-17. The PR-5 family is composed of thaumatin-like proteins (TLPs), which are responsive to biotic and abiotic stress and are widely studied in plants. TLPs were also recently discovered in fungi and animals. In the poplar genome, TLPs are over-represented compared with annual species and their transcripts strongly accumulate during stress conditions. Results Our analysis of the poplar TLP family suggests that the expansion of this gene family was followed by diversification, as differences in expression patterns and predicted properties correlate with phylogeny. In particular, we identified a clade of poplar TLPs that cluster to a single 350 kb locus of chromosome I and that are up-regulated by poplar leaf rust infection. A wider phylogenetic analysis of eukaryote TLPs - including plant, animal and fungi sequences - shows that TLP gene content and diversity increased markedly during land plant evolution. Mapping the reported functions of characterized TLPs to the eukaryote phylogenetic tree showed that antifungal or glycan-lytic properties are widespread across eukaryote phylogeny, suggesting that these properties are shared by most TLPs and are likely associated with the presence of a conserved acidic cleft in their 3D structure. Also, we established an exhaustive catalog of TLPs with atypical architectures such as small-TLPs, TLP-kinases and small-TLP-kinases, which have potentially developed alternative functions (such as putative receptor kinases for pathogen sensing and signaling). Conclusion Our study, based on the most recent plant genome sequences, provides evidence for TLP gene family diversification during land plant evolution. We have shown that the diverse functions described for TLPs are not restricted to specific clades but seem to be universal among

  13. Investigating the role of extensin proteins in poplar biomass recalcitrance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The biological conversion of cellulosic biomass to biofuel is hindered by cell wall recalcitrance, which can limit the ability of cellulases to access and break down cellulose. The purpose of this study was to investigate whether hydroxyproline-rich cell wall proteins (extensins) are present in popl...

  14. Expansion and diversification of BTL ring-H2 ubiquitin ligases in angiosperms: putative Rabring7/BCA2 orthologs.

    PubMed

    Aguilar-Hernández, Victor; Medina, Juliana; Aguilar-Henonin, Laura; Guzmán, Plinio

    2013-01-01

    RING finger E3 ligases are components of the ubiquitin proteasome system (UPS) that mediate the transfer of ubiquitin to substrates. Single-subunit RING finger E3s binds the E2 ubiquitin-conjugating enzyme and contains recognition sequences for the substrate within the same polypeptide. Here we describe the characterization of a class of RING finger E3 ligases that is conserved among eukaryotes. This class encodes a RING-H2 domain related in sequence to the ATL RING-H2 domain, another class of E3 ligases, and a C2/C2 zing finger at the amino-terminus, formerly described as BZF. In viridiplantae (green algae and land plants), we designed this family as BTL for BZF ATLs. BTLs are putative orthologs of the mammalian Rabring7/BCA2 RING-H2 E3s that have expanded in angiosperms. They are found in numbers ranging from three to thirty-one, which is in contrast to the one to three members normally found in animals, fungi, and protists. Furthermore, the number of sequence LOGOs generated in angiosperms is four times greater than that in other eukaryotes. In contrast to ATLs, which show expansion by tandem duplication, tandemly duplicated BTLs are scarce. The mode of action of Rabring7/BCA2 and BTLs may be similar since both the Rabring7/BCA2 BZF and the ath|BTL4 BZF are likely to mediate the binding of ubiquitin. This study introduces valuable information on the evolution and domain structure of the Rabring7/BCA2/BTL class of E3 ligases which may be important for core eukaryotic genes.

  15. Expansion and Diversification of BTL Ring-H2 Ubiquitin Ligases in Angiosperms: Putative Rabring7/BCA2 Orthologs

    PubMed Central

    Aguilar-Henonin, Laura; Guzmán, Plinio

    2013-01-01

    RING finger E3 ligases are components of the ubiquitin proteasome system (UPS) that mediate the transfer of ubiquitin to substrates. Single-subunit RING finger E3s binds the E2 ubiquitin-conjugating enzyme and contains recognition sequences for the substrate within the same polypeptide. Here we describe the characterization of a class of RING finger E3 ligases that is conserved among eukaryotes. This class encodes a RING-H2 domain related in sequence to the ATL RING-H2 domain, another class of E3 ligases, and a C2/C2 zing finger at the amino-terminus, formerly described as BZF. In viridiplantae (green algae and land plants), we designed this family as BTL for BZF ATLs. BTLs are putative orthologs of the mammalian Rabring7/BCA2 RING-H2 E3s that have expanded in angiosperms. They are found in numbers ranging from three to thirty-one, which is in contrast to the one to three members normally found in animals, fungi, and protists. Furthermore, the number of sequence LOGOs generated in angiosperms is four times greater than that in other eukaryotes. In contrast to ATLs, which show expansion by tandem duplication, tandemly duplicated BTLs are scarce. The mode of action of Rabring7/BCA2 and BTLs may be similar since both the Rabring7/BCA2 BZF and the ath|BTL4 BZF are likely to mediate the binding of ubiquitin. This study introduces valuable information on the evolution and domain structure of the Rabring7/BCA2/BTL class of E3 ligases which may be important for core eukaryotic genes. PMID:23951330

  16. Cobalt-60 gamma-ray irradiation pretreatment and sludge protein for enhancing enzymatic saccharification of hybrid poplar sawdust.

    PubMed

    Xiang, Yulin; Xiang, Yuxiu; Wang, Lipeng

    2016-12-01

    In order to improve the enzymatic saccharification of hybrid poplar sawdust, gamma irradiation pretreatment and enzymatic hydrolysis in the presence of sludge protein were investigated. The cellulose crystallinity index were significantly decreased after irradiation pretreatment, and adding sludge protein improved enzyme activity and increased the reducing sugar yield. The conditions of irradiation pretreatment and enzymatic hydrolysis in the presence of sludge protein were systematically examined. The maximum reducing sugar yield was 519mg/g under an irradiation dose of 300kGy, a sludge protein dosage of 2mg/mL, an enzymatic hydrolysis temperature of 45°C, an enzymatic hydrolysis time of 84h, and a 90FPU/g enzyme loading. This work indicated that the combined method of gamma irradiation pretreatment and enzymatic hydrolysis in the presence of sludge protein was a promising potential for the saccharification of hybrid poplar sawdust.

  17. PJA1, encoding a RING-H2 finger ubiquitin ligase, is a novel human X chromosome gene abundantly expressed in brain.

    PubMed

    Yu, Ping; Chen, Yiwang; Tagle, Danilo A; Cai, Tao

    2002-06-01

    RING-finger proteins contain cysteine-rich, zinc-binding domains and are involved in the formation of macromolecular scaffolds important for transcriptional repression and ubiquitination. In this study, we have identified a RING-H2 finger gene, PJA1 (for praja-1), from a human brain cDNA library and mapped it to human chromosome Xq12 between markers DXS983 and DXS1216, a region implicated in X-linked mental retardation (MRX). Northern blot analysis indicated a 2.7-kb transcript that was abundantly expressed in the brain, including regions of the cerebellum, cerebral cortex, medulla, occipital pole, frontal lobe, temporal lobe, and putamen. Amino acid sequence analysis of the 71-kDa protein PJA1 showed 52.3% identity to human PJA2 (for praja-2, also known as NEURODAP1/KIAA0438) and also a significant identity to its homologs in rat, mouse, and zebrafish. In vitro binding and immunoprecipitation assays demonstrated that both PJA1 and PJA2 are able to bind the ubiquitin-conjugating enzyme UbcH5B. Moreover, the ubiquitination assay indicated that PJA1 and PJA2 have an E2-dependent E3 ubiquitin ligase activity. Thus our findings demonstrate that PJA1 can be involved in protein ubiquitination in the brain and is a suitable candidate gene for MRX.

  18. The Poplar Rust-Induced Secreted Protein (RISP) Inhibits the Growth of the Leaf Rust Pathogen Melampsora larici-populina and Triggers Cell Culture Alkalinisation

    PubMed Central

    Petre, Benjamin; Hecker, Arnaud; Germain, Hugo; Tsan, Pascale; Sklenar, Jan; Pelletier, Gervais; Séguin, Armand; Duplessis, Sébastien; Rouhier, Nicolas

    2016-01-01

    Plant cells secrete a wide range of proteins in extracellular spaces in response to pathogen attack. The poplar rust-induced secreted protein (RISP) is a small cationic protein of unknown function that was identified as the most induced gene in poplar leaves during immune responses to the leaf rust pathogen Melampsora larici-populina, an obligate biotrophic parasite. Here, we combined in planta and in vitro molecular biology approaches to tackle the function of RISP. Using a RISP-mCherry fusion transiently expressed in Nicotiana benthamiana leaves, we demonstrated that RISP is secreted into the apoplast. A recombinant RISP specifically binds to M. larici-populina urediniospores and inhibits their germination. It also arrests the growth of the fungus in vitro and on poplar leaves. Interestingly, RISP also triggers poplar cell culture alkalinisation and is cleaved at the C-terminus by a plant-encoded mechanism. Altogether our results indicate that RISP is an antifungal protein that has the ability to trigger cellular responses. PMID:26925067

  19. Down-regulation of plasma intrinsic protein1 aquaporin in poplar trees is detrimental to recovery from embolism.

    PubMed

    Secchi, Francesca; Zwieniecki, Maciej A

    2014-04-01

    During their lifecycles, trees encounter multiple events of water stress that often result in embolism formation and temporal decreases in xylem transport capacity. The restoration of xylem transport capacity requires changes in cell metabolic activity and gene expression. Specifically, in poplar (Populus spp.), the formation of xylem embolisms leads to a clear up-regulation of plasma membrane protein1 (PIP1) aquaporin genes. To determine their role in poplar response to water stress, transgenic Populus tremula × Populus alba plants characterized by the strong down-regulation of multiple isoforms belonging to the PIP1 subfamily were used. Transgenic lines showed that they are more vulnerable to embolism, with 50% percent loss of conductance occurring 0.3 MPa earlier than in wild-type plants, and that they also have a reduced capacity to restore xylem conductance during recovery. Transgenic plants also show symptoms of a reduced capacity to control percent loss of conductance through stomatal conductance in response to drought, because they have a much narrower vulnerability safety margin. Finally, a delay in stomatal conductance recovery during the period of stress relief was observed. The presented results suggest that PIP1 genes are involved in the maintenance of xylem transport system capacity, in the promotion of recovery from stress, and in contribution to a plant's control of stomatal conductance under water stress.

  20. The effects of gamma irradiation on growth and expression of genes encoding DNA repair-related proteins in Lombardy poplar (Populus nigra var. italica).

    PubMed

    Nishiguchi, Mitsuru; Nanjo, Tokihiko; Yoshida, Kazumasa

    2012-07-01

    In this study, to elucidate the mechanisms of adaptation and tolerance to ionizing radiation in woody plants, we investigated the various biological effects of γ-rays on the Lombardy poplar (Populus nigra L. var. italica Du Roi). We detected abnormal leaf shape and color, fusion, distorted venation, shortened internode, fasciation and increased axillary shoots in γ-irradiated poplar plants. Acute γ-irradiation with a dose of 100Gy greatly reduced the height, stem diameter and biomass of poplar plantlets. After receiving doses of 200 and 300Gy, all the plantlets stopped growing, and then most of them withered after 4-10 weeks of γ-irradiation. Comet assays showed that nuclear DNA in suspension-cultured poplar cells had been damaged by γ-rays. To determine whether DNA repair-related proteins are involved in the response to γ-rays in Lombardy poplars, we cloned the PnRAD51, PnLIG4, PnKU70, PnXRCC4, PnPCNA and PnOGG1 cDNAs and investigated their mRNA expression. The PnRAD51, PnLIG4, PnKU70, PnXRCC4 and PnPCNA mRNAs were increased by γ-rays, but the PnOGG1 mRNA was decreased. Moreover, the expression of PnLIG4, PnKU70 and PnRAD51 was also up-regulated by Zeocin known as a DNA cleavage agent. These observations suggest that the morphogenesis, growth and protective gene expression in Lombardy poplars are severely affected by the DNA damage and unknown cellular events caused by γ-irradiation.

  1. Plantation forestry under global warming: hybrid poplars with improved thermotolerance provide new insights on the in vivo function of small heat shock protein chaperones.

    PubMed

    Merino, Irene; Contreras, Angela; Jing, Zhong-Ping; Gallardo, Fernando; Cánovas, Francisco M; Gómez, Luis

    2014-02-01

    Climate-driven heat stress is a key factor affecting forest plantation yields. While its effects are expected to worsen during this century, breeding more tolerant genotypes has proven elusive. We report here a substantial and durable increase in the thermotolerance of hybrid poplar (Populus tremula×Populus alba) through overexpression of a major small heat shock protein (sHSP) with convenient features. Experimental evidence was obtained linking protective effects in the transgenic events with the unique chaperone activity of sHSPs. In addition, significant positive correlations were observed between phenotype strength and heterologous sHSP accumulation. The remarkable baseline levels of transgene product (up to 1.8% of total leaf protein) have not been reported in analogous studies with herbaceous species. As judged by protein analyses, such an accumulation is not matched either by endogenous sHSPs in both heat-stressed poplar plants and field-grown adult trees. Quantitative real time-polymerase chain reaction analyses supported these observations and allowed us to identify the poplar members most responsive to heat stress. Interestingly, sHSP overaccumulation was not associated with pleiotropic effects that might decrease yields. The poplar lines developed here also outperformed controls under in vitro and ex vitro culture conditions (callus biomass, shoot production, and ex vitro survival), even in the absence of thermal stress. These results reinforce the feasibility of improving valuable genotypes for plantation forestry, a field where in vitro recalcitrance, long breeding cycles, and other practical factors constrain conventional genetic approaches. They also provide new insights into the biological functions of the least understood family of heat shock protein chaperones.

  2. Plantation Forestry under Global Warming: Hybrid Poplars with Improved Thermotolerance Provide New Insights on the in Vivo Function of Small Heat Shock Protein Chaperones1[C][W

    PubMed Central

    Merino, Irene; Contreras, Angela; Jing, Zhong-Ping; Gallardo, Fernando; Cánovas, Francisco M.; Gómez, Luis

    2014-01-01

    Climate-driven heat stress is a key factor affecting forest plantation yields. While its effects are expected to worsen during this century, breeding more tolerant genotypes has proven elusive. We report here a substantial and durable increase in the thermotolerance of hybrid poplar (Populus tremula × Populus alba) through overexpression of a major small heat shock protein (sHSP) with convenient features. Experimental evidence was obtained linking protective effects in the transgenic events with the unique chaperone activity of sHSPs. In addition, significant positive correlations were observed between phenotype strength and heterologous sHSP accumulation. The remarkable baseline levels of transgene product (up to 1.8% of total leaf protein) have not been reported in analogous studies with herbaceous species. As judged by protein analyses, such an accumulation is not matched either by endogenous sHSPs in both heat-stressed poplar plants and field-grown adult trees. Quantitative real time-polymerase chain reaction analyses supported these observations and allowed us to identify the poplar members most responsive to heat stress. Interestingly, sHSP overaccumulation was not associated with pleiotropic effects that might decrease yields. The poplar lines developed here also outperformed controls under in vitro and ex vitro culture conditions (callus biomass, shoot production, and ex vitro survival), even in the absence of thermal stress. These results reinforce the feasibility of improving valuable genotypes for plantation forestry, a field where in vitro recalcitrance, long breeding cycles, and other practical factors constrain conventional genetic approaches. They also provide new insights into the biological functions of the least understood family of heat shock protein chaperones. PMID:24306533

  3. Comparative analysis of secreted protein evolution using expressed sequence tags from four poplar leaf rusts (Melampsora spp.)

    PubMed Central

    2010-01-01

    Background Obligate biotrophs such as rust fungi are believed to establish long-term relationships by modulating plant defenses through a plethora of effector proteins, whose most recognizable feature is the presence of a signal peptide for secretion. Since the phenotypes of these effectors extend to host cells, their genes are expected to be under accelerated evolution stimulated by host-pathogen coevolutionary arms races. Recently, whole genome sequence data has allowed the prediction of secretomes, facilitating the identification of putative effectors. Results We generated cDNA libraries from four poplar leaf rust pathogens (Melampsora spp.) and used computational approaches to identify and annotate putative secreted proteins with the aim of uncovering new knowledge about the nature and evolution of the rust secretome. While more than half of the predicted secretome members encoded lineage-specific proteins, similarities with experimentally characterized fungal effectors were also identified. A SAGE analysis indicated a strong stage-specific regulation of transcripts encoding secreted proteins. The average sequence identity of putative secreted proteins to their closest orthologs in the wheat stem rust Puccinia graminis f. sp. tritici was dramatically reduced compared with non-secreted ones. A comparative genomics approach based on homologous gene groups unravelled positive selection in putative members of the secretome. Conclusion We uncovered robust evidence that different evolutionary constraints are acting on the rust secretome when compared to the rest of the genome. These results are consistent with the view that these genes are more likely to exhibit an effector activity and be involved in coevolutionary arms races with host factors. PMID:20615251

  4. Drought, salt and wounding stress induce the expression of the plasma membrane intrinsic protein 1 gene in poplar (Populus alba×P. tremula var. glandulosa).

    PubMed

    Bae, Eun-Kyung; Lee, Hyoshin; Lee, Jae-Soon; Noh, Eun-Woon

    2011-09-01

    Water uptake across cell membranes is a principal requirement for plant growth at both the cellular and whole-plant levels; water movement through plant membranes is regulated by aquaporins (AQPs) or major intrinsic proteins (MIPs). We examined the expression characteristics of the poplar plasma membrane intrinsic protein 1 gene (PatPIP1), a type of MIP, which was isolated from a suspension cell cDNA library of Populus alba×P. tremula var. glandulosa. Examination of protoplasts expressing the p35S-PatPIP1::sGFP fusion protein revealed that the protein was localized in the plasma membrane. Northern blot analysis revealed that the gene was strongly expressed in poplar roots and leaves. Gene expression was inducible by abiotic factors including drought, salinity, cold temperatures and wounding, and also by plant hormones including gibberellic acid, jasmonic acid and salicylic acid. Since we found that the PatPIP1 gene was strongly expressed in response to mannitol, NaCl, jasmonic acid and wounding, we propose that PatPIP1 plays an essential role in the defense of plants against water stress.

  5. Response of the Gypsy Moth, Lymantria dispar to Transgenic Poplar, Populus simonii x P. nigra, Expressing Fusion Protein Gene of the Spider Insecticidal Peptide and Bt-toxin C-peptide

    PubMed Central

    Cao, Chuan-Wang; Liu, Gui-Feng; Wang, Zhi-Ying; Yan, Shan-Chun; Ma, Ling; Yang, Chuan-Ping

    2010-01-01

    The response of the Asian gypsy moth Lymantria dispar (L.) (Lepidoptera: Lymantriidae) to a fusion gene consisting of the spider, Atrax robustus Simon (Araneae: Hexanthelidae) ω?-ACTX-Ar1 sequence coding for an ω?-atracotoxin and a sequence coding for the Bt-toxin C-peptide, expressed in transgenic poplar Populus simonii x P. nigra L. (Malphigiales: Salicaceae) was investigated. Individual performance, feeding selection, midgut proteinase activity and nutrition utilization were monitored. The growth and development of L. dispar were significantly affected by continually feeding on the transgenic poplar, with the larval instars displaying significantly shorter developmental times than those fed on nontransgenic poplar, but pupation was delayed. Mortality was higher in populations fed transgenic poplar leaves, than for larvae fed nontransgenic poplar leaves. The cumulative mortality during all stages of larvae fed transgenic leaves was 92% compared to 16.7% of larvae on nontransgenic leaves. The highest mortality observed was 71.7% in the last larval instar stage. A two-choice test showed that fifth-instar larvae preferred to feed on nontransgenic leaves at a ratio of 1:1.4. Feeding on transgenic leaves had highly significant negative effects on relative growth of larvae, and the efficiency of conversion of ingested and digested food. Activity of major midgut proteinases was measured using substrates TAME and BTEE showed significant increases in tryptase and chymotrypsinlike activity (9.2- and 9.0-fold, respectively) in fifth-instar larvae fed on transgenic leaves over control. These results suggest transgenic poplar is resistant to L. dispar, and the mature L. dispar may be weakened by the transgenic plants due to Bt protoxins activated by elevated major midgut proteinase activity. The new transgenic poplar expressing fusion protein genes of Bt and a new spider insecticidal peptide are good candidates for managing gypsy moth. PMID:21268699

  6. Response of the gypsy moth, Lymantria dispar to transgenic poplar, Populus simonii x P. nigra, expressing fusion protein gene of the spider insecticidal peptide and Bt-toxin C-peptide.

    PubMed

    Cao, Chuan-Wang; Liu, Gui-Feng; Wang, Zhi-Ying; Yan, Shan-Chun; Ma, Ling; Yang, Chuan-Ping

    2010-01-01

    The response of the Asian gypsy moth Lymantria dispar (L.) (Lepidoptera: Lymantriidae) to a fusion gene consisting of the spider, Atrax robustus Simon (Araneae: Hexanthelidae) ω-ACTX-Ar1 sequence coding for an ω-atracotoxin and a sequence coding for the Bt-toxin C-peptide, expressed in transgenic poplar Populus simonii x P. nigra L. (Malphigiales: Salicaceae) was investigated. Individual performance, feeding selection, midgut proteinase activity and nutrition utilization were monitored. The growth and development of L. dispar were significantly affected by continually feeding on the transgenic poplar, with the larval instars displaying significantly shorter developmental times than those fed on nontransgenic poplar, but pupation was delayed. Mortality was higher in populations fed transgenic poplar leaves, than for larvae fed nontransgenic poplar leaves. The cumulative mortality during all stages of larvae fed transgenic leaves was 92% compared to 16.7% of larvae on nontransgenic leaves. The highest mortality observed was 71.7% in the last larval instar stage. A two-choice test showed that fifth-instar larvae preferred to feed on nontransgenic leaves at a ratio of 1:1.4. Feeding on transgenic leaves had highly significant negative effects on relative growth of larvae, and the efficiency of conversion of ingested and digested food. Activity of major midgut proteinases was measured using substrates TAME and BTEE showed significant increases in tryptase and chymotrypsinlike activity (9.2- and 9.0-fold, respectively) in fifth-instar larvae fed on transgenic leaves over control. These results suggest transgenic poplar is resistant to L. dispar, and the mature L. dispar may be weakened by the transgenic plants due to Bt protoxins activated by elevated major midgut proteinase activity. The new transgenic poplar expressing fusion protein genes of Bt and a new spider insecticidal peptide are good candidates for managing gypsy moth.

  7. Proteomic Analysis of a Poplar Cell Suspension Culture Suggests a Major Role of Protein S-Acylation in Diverse Cellular Processes

    PubMed Central

    Srivastava, Vaibhav; Weber, Joseph R.; Malm, Erik; Fouke, Bruce W.; Bulone, Vincent

    2016-01-01

    S-acylation is a reversible post-translational modification of proteins known to be involved in membrane targeting, subcellular trafficking, and the determination of a great variety of functional properties of proteins. The aim of this work was to identify S-acylated proteins in poplar. The use of an acyl-biotin exchange method and mass spectrometry allowed the identification of around 450 S-acylated proteins, which were subdivided into three major groups of proteins involved in transport, signal transduction, and response to stress, respectively. The largest group of S-acylated proteins was the protein kinase superfamily. Soluble N-ethylmaleimide-sensitive factor-activating protein receptors, band 7 family proteins and tetraspanins, all primarily related to intracellular trafficking, were also identified. In addition, cell wall related proteins, including cellulose synthases and other glucan synthases, were found to be S-acylated. Twenty four of the identified S-acylated proteins were also enriched in detergent-resistant membrane microdomains, suggesting S-acylation plays a key role in the localization of proteins to specialized plasma membrane subdomains. This dataset promises to enhance our current understanding of the various functions of S-acylated proteins in plants. PMID:27148305

  8. The zinc finger protein PtaZFP2 negatively controls stem growth and gene expression responsiveness to external mechanical loads in poplar.

    PubMed

    Martin, Ludovic; Decourteix, Mélanie; Badel, Eric; Huguet, Stéphanie; Moulia, Bruno; Julien, Jean-Louis; Leblanc-Fournier, Nathalie

    2014-07-01

    Mechanical cues are essential signals regulating plant growth and development. In response to wind, trees develop a thigmomorphogenetic response characterized by a reduction in longitudinal growth, an increase in diameter growth, and changes in mechanical properties. The molecular mechanisms behind these processes are poorly understood. In poplar, PtaZFP2, a C2H2 transcription factor, is rapidly up-regulated after stem bending. To investigate the function of PtaZFP2, we analyzed PtaZFP2-overexpressing poplars (Populus tremula × Populus alba). To unravel the genes downstream PtaZFP2, a transcriptomic analysis was performed. PtaZFP2-overexpressing poplars showed longitudinal and cambial growth reductions together with an increase in the tangent and hardening plastic moduli. The regulation level of mechanoresponsive genes was much weaker after stem bending in PtaZFP2-overexpressing poplars than in wild-type plants, showing that PtaZFP2 negatively modulates plant responsiveness to mechanical stimulation. Microarray analysis revealed a high proportion of down-regulated genes in PtaZFP2-overexpressing poplars. Among these genes, several were also shown to be regulated by mechanical stimulation. Our results confirmed the important role of PtaZFP2 during plant acclimation to mechanical load, in particular through a negative control of plant molecular responsiveness. This desensitization process could modulate the amplitude and duration of the plant response during recurrent stimuli.

  9. Atypical protein disulfide isomerases (PDI): Comparison of the molecular and catalytic properties of poplar PDI-A and PDI-M with PDI-L1A

    PubMed Central

    Selles, Benjamin; Zannini, Flavien; Couturier, Jérémy; Jacquot, Jean-Pierre

    2017-01-01

    Protein disulfide isomerases are overwhelmingly multi-modular redox catalysts able to perform the formation, reduction or isomerisation of disulfide bonds. We present here the biochemical characterization of three different poplar PDI isoforms. PDI-A is characterized by a single catalytic Trx module, the so-called a domain, whereas PDI-L1a and PDI-M display an a-b-b’-a’ and a°-a-b organisation respectively. Their activities have been tested in vitro using purified recombinant proteins and a series of model substrates as insulin, NADPH thioredoxin reductase, NADP malate dehydrogenase (NADP-MDH), peroxiredoxins or RNase A. We demonstrated that PDI-A exhibited none of the usually reported activities, although the cysteines of the WCKHC active site signature are able to form a disulfide with a redox midpoint potential of -170 mV at pH 7.0. The fact that it is able to bind a [Fe2S2] cluster upon Escherichia coli expression and anaerobic purification might indicate that it does not have a function in dithiol-disulfide exchange reactions. The two other proteins were able to catalyze oxidation or reduction reactions, PDI-L1a being more efficient in most cases, except that it was unable to activate the non-physiological substrate NADP-MDH, in contrast to PDI-M. To further evaluate the contribution of the catalytic domains of PDI-M, the dicysteinic motifs have been independently mutated in each a domain. The results indicated that the two a domains seem interconnected and that the a° module preferentially catalyzed oxidation reactions whereas the a module catalyzed reduction reactions, in line with the respective redox potentials of -170 mV and -190 mV at pH 7.0. Overall, these in vitro results illustrate that the number and position of a and b domains influence the redox properties and substrate recognition (both electron donors and acceptors) of PDI which contributes to understand why this protein family expanded along evolution. PMID:28362814

  10. The MYB182 Protein Down-Regulates Proanthocyanidin and Anthocyanin Biosynthesis in Poplar by Repressing Both Structural and Regulatory Flavonoid Genes1[OPEN

    PubMed Central

    Yoshida, Kazuko; Ma, Dawei; Constabel, C. Peter

    2015-01-01

    Trees in the genus Populus (poplar) contain phenolic secondary metabolites including the proanthocyanidins (PAs), which help to adapt these widespread trees to diverse environments. The transcriptional activation of PA biosynthesis in response to herbivory and ultraviolet light stress has been documented in poplar leaves, and a regulator of this process, the R2R3-MYB transcription factor MYB134, has been identified. MYB134-overexpressing transgenic plants show a strong high-PA phenotype. Analysis of these transgenic plants suggested the involvement of additional MYB transcription factors, including repressor-like MYB factors. Here, MYB182, a subgroup 4 MYB factor, was found to act as a negative regulator of the flavonoid pathway. Overexpression of MYB182 in hairy root culture and whole poplar plants led to reduced PA and anthocyanin levels as well as a reduction in the expression of key flavonoid genes. Similarly, a reduced accumulation of transcripts of a MYB PA activator and a basic helix-loop-helix cofactor was observed in MYB182-overexpressing hairy roots. Transient promoter activation assays in poplar cell culture demonstrated that MYB182 can disrupt transcriptional activation by MYB134 and that the basic helix-loop-helix-binding motif of MYB182 was essential for repression. Microarray analysis of transgenic plants demonstrated that down-regulated targets of MYB182 also include shikimate pathway genes. This work shows that MYB182 plays an important role in the fine-tuning of MYB134-mediated flavonoid metabolism. PMID:25624398

  11. Sequencing the genome of Marssonina brunnea reveals fungus-poplar co-evolution

    PubMed Central

    2012-01-01

    Background The fungus Marssonina brunnea is a causal pathogen of Marssonina leaf spot that devastates poplar plantations by defoliating susceptible trees before normal fall leaf drop. Results We sequence the genome of M. brunnea with a size of 52 Mb assembled into 89 scaffolds, representing the first sequenced Dermateaceae genome. By inoculating this fungus onto a poplar hybrid clone, we investigate how M. brunnea interacts and co-evolves with its host to colonize poplar leaves. While a handful of virulence genes in M. brunnea, mostly from the LysM family, are detected to up-regulate during infection, the poplar down-regulates its resistance genes, such as nucleotide binding site domains and leucine rich repeats, in response to infection. From 10,027 predicted proteins of M. brunnea in a comparison with those from poplar, we identify four poplar transferases that stimulate the host to resist M. brunnea. These transferas-encoding genes may have driven the co-evolution of M. brunnea and Populus during the process of infection and anti-infection. Conclusions Our results from the draft sequence of the M. brunnea genome provide evidence for genome-genome interactions that play an important role in poplar-pathogen co-evolution. This knowledge could help to design effective strategies for controlling Marssonina leaf spot in poplar. PMID:22876864

  12. Stress-responsive mitogen-activated protein kinases interact with the EAR motif of a poplar zinc finger protein and mediate its degradation through the 26S proteasome.

    PubMed

    Hamel, Louis-Philippe; Benchabane, Meriem; Nicole, Marie-Claude; Major, Ian T; Morency, Marie-Josée; Pelletier, Gervais; Beaudoin, Nathalie; Sheen, Jen; Séguin, Armand

    2011-11-01

    Mitogen-activated protein kinases (MAPKs) contribute to the establishment of plant disease resistance by regulating downstream signaling components, including transcription factors. In this study, we identified MAPK-interacting proteins, and among the newly discovered candidates was a Cys-2/His-2-type zinc finger protein named PtiZFP1. This putative transcription factor belongs to a family of transcriptional repressors that rely on an ERF-associated amphiphilic repression (EAR) motif for their repression activity. Amino acids located within this repression motif were also found to be essential for MAPK binding. Close examination of the primary protein sequence revealed a functional bipartite MAPK docking site that partially overlaps with the EAR motif. Transient expression assays in Arabidopsis (Arabidopsis thaliana) protoplasts suggest that MAPKs promote PtiZFP1 degradation through the 26S proteasome. Since features of the MAPK docking site are conserved among other EAR repressors, our study suggests a novel mode of defense mechanism regulation involving stress-responsive MAPKs and EAR repressors.

  13. Molecular dissection of xylan biosynthesis during wood formation in poplar.

    PubMed

    Lee, Chanhui; Teng, Quincy; Zhong, Ruiqin; Ye, Zheng-Hua

    2011-07-01

    Xylan, being the second most abundant polysaccharide in dicot wood, is considered to be one of the factors contributing to wood biomass recalcitrance for biofuel production. To better utilize wood as biofuel feedstock, it is crucial to functionally characterize all the genes involved in xylan biosynthesis during wood formation. In this report, we investigated roles of poplar families GT43 and GT8 glycosyltransferases in xylan biosynthesis during wood formation. There exist seven GT43 genes in the genome of poplar (Populus trichocarpa), five of which, namely PtrGT43A, PtrGT43B, PtrGT43C, PtrGT43D, and PtrGT43E, were shown to be highly expressed in the developing wood and their encoded proteins were localized in the Golgi. Comprehensive genetic complementation coupled with chemical analyses demonstrated that overexpression of PtrGT43A/B/E but not PtrGT43C/D was able to rescue the xylan defects conferred by the Arabidopsis irx9 mutant, whereas overexpression of PtrGT43C/D but not PtrGT43A/B/E led to a complementation of the xylan defects in the Arabidopsis irx14 mutant. The essential roles of poplar GT43 members in xylan biosynthesis was further substantiated by RNAi down-regulation of GT43B in the hybrid poplar (Populus alba x tremula) leading to reductions in wall thickness and xylan content in wood, and an elevation in the abundance of the xylan reducing end sequence. Wood digestibility analysis revealed that cellulase digestion released more glucose from the wood of poplar GT43B RNAi lines than the control wood, indicating a decrease in wood biomass recalcitrance. Furthermore, RNAi down-regulation of another poplar wood-associated glycosyltransferase, PoGT8D, was shown to cause decreases in wall thickness and xylan content as well as in the abundance of the xylan reducing end sequence. Together, these findings demonstrate that the poplar GT43 members form two functionally non-redundant groups, namely PtrGT43A/B/E as functional orthologs of Arabidopsis IRX9 and Ptr

  14. Mercury uptake into poplar leaves.

    PubMed

    Assad, Mohamad; Parelle, Julien; Cazaux, David; Gimbert, Frédéric; Chalot, Michel; Tatin-Froux, Fabienne

    2016-03-01

    Tailings dumps require mercury stabilization to prevent air pollution by evaporated mercury, which can be achieved through plant covers. Plants are considered a net sink for atmospheric Hg via incorporation into leaf tissues. However, most studies related to Hg uptake by plants have considered plants exposed to only atmospheric Hg, whereas in the case of tailings dumps, plants are potentially exposed to both soil and atmospheric Hg. The goal of this work is to evaluate the relative contributions of root and atmospheric pathways by growing poplar (Populus trichocarpa X Populus maximowiczii/var Skado) cuttings on either control or polluted substrates and under either natural or controlled exposure conditions. We showed that foliar Hg concentrations significantly increased with age, reaching 120 ng g(-1) dry mass when poplars were exposed to Hg-contaminated substrate under natural exposure. Remarkably, we did not observe significantly different Hg concentrations in poplar leaves grown on either the control or polluted substrates when cultivated together in growth chambers. Our set of data prompted us to conclude that Hg entry into poplar leaves is exclusively through an atmospheric pathway. Our results are discussed in line with existing literature.

  15. Proteome Analysis of Poplar Seed Vigor.

    PubMed

    Zhang, Hong; Wang, Wei-Qing; Liu, Shu-Jun; Møller, Ian Max; Song, Song-Quan

    2015-01-01

    Seed vigor is a complex property that determines the seed's potential for rapid uniform emergence and subsequent growth. However, the mechanism for change in seed vigor is poorly understood. The seeds of poplar (Populus × Canadensis Moench), which are short-lived, were stored at 30 °C and 75 ± 5% relative humidity for different periods of time (0-90 days) to obtain different vigor seeds (from 95 to 0% germination). With decreasing seed vigor, the temperature range of seed germination became narrower; the respiration rate of the seeds decreased markedly, while the relative electrolyte leakage increased markedly, both levelling off after 45 days. A total of 81 protein spots showed a significant change in abundance (≥ 1.5-fold, P < 0.05) when comparing the proteomes among seeds with different vigor. Of the identified 65 proteins, most belonged to the groups involved in metabolism (23%), protein synthesis and destination (22%), energy (18%), cell defense and rescue (17%), and storage protein (15%). These proteins accounted for 95% of all the identified proteins. During seed aging, 53 and 6 identified proteins consistently increased and decreased in abundance, respectively, and they were associated with metabolism (22%), protein synthesis and destination (22%), energy (19%), cell defense and rescue (19%), storage proteins (15%), and cell growth and structure (3%). These data show that the decrease in seed vigor (aging) is an energy-dependent process, which requires protein synthesis and degradation as well as cellular defense and rescue.

  16. 76 FR 28308 - Modification of Class E Airspace; Poplar, MT

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-17

    ... airspace at Poplar Municipal Airport, Poplar, MT. The airport was moved 1.5 Nautical Miles (NM) to the... Airport, Poplar, MT. The airport was moved 1.5 nautical miles to the northeast, and controlled...

  17. Low temperatures counteract short-day induced nitrogen storage, but not accumulation of bark storage protein transcripts in bark of grey poplar (Populus × canescens) trees.

    PubMed

    Wildhagen, H; Bilela, S; Rennenberg, H

    2013-01-01

    According to climate change scenarios, the seasonal course of temperature will change in most regions of the world, raising the question of how this will influence seasonal nitrogen (N) storage in deciduous trees. The key to this question is a detailed understanding of the underlying regulatory mechanisms, which was addressed in this study by analysing (i) the effects of low temperatures (13-1 °C) on bark storage protein (BSP) transcription, BSP and total protein accumulation and amino acid metabolism; (ii) the effects of interactions between low temperatures and photoperiod on these processes; and (iii) the regulatory role of amino acids in the bark. For this purpose, we exposed grey poplar trees (Populus × canescens) to three different treatments of changing photoperiod at constant temperature, changing temperature at constant photoperiod, and both changing photoperiod and temperature. Under a shortened photoperiod, a substantial increase of BSP transcripts was observed that was correlated with the accumulation of bark proteins, indicating a metabolic shift to promote long-term N storage. Irrespective of the applied photoperiod, exposure to low temperatures (5 or 1 °C) caused a strong increase of BSP transcripts, which was not paralled by significant increases of BSP and total bark proteins. We conclude that the interaction between effects of photoperiod and temperature is dependent on the carbon status of the trees, and reflects a metabolic adjustment of reduced carbon consumption for BSP synthesis. These results demonstrate the differential temperature sensitivity of processes involved in seasonal N storage, implying vulnerability to changing environmental conditions.

  18. Analysis of 4,664 high-quality sequence-finished poplar full-length

    SciTech Connect

    Ralph, S.; Gunter, Lee E; Tuskan, Gerald A; Douglas, Carl; Holt, Robert A.; Jones, Steven; Marra, Marco; Bohlmann, J.

    2008-01-01

    The genus Populus includes poplars, aspens and cottonwoods, which will be collectively referred to as poplars hereafter unless otherwise specified. Poplars are the dominant tree species in many forest ecosystems in the Northern Hemisphere and are of substantial economic value in plantation forestry. Poplar has been established as a model system for genomics studies of growth, development, and adaptation of woody perennial plants including secondary xylem formation, dormancy, adaptation to local environments, and biotic interactions. As part of the poplar genome sequencing project and the development of genomic resources for poplar, we have generated a full-length (FL)-cDNA collection using the biotinylated CAP trapper method. We constructed four FLcDNA libraries using RNA from xylem, phloem and cambium, and green shoot tips and leaves from the P. trichocarpa Nisqually-1 genotype, as well as insect-attacked leaves of the P. trichocarpa x P. deltoides hybrid. Following careful selection of candidate cDNA clones, we used a combined strategy of paired end reads and primer walking to generate a set of 4,664 high-accuracy, sequence-verified FLcDNAs, which clustered into 3,990 putative unique genes. Mapping FLcDNAs to the poplar genome sequence combined with BLAST comparisons to previously predicted protein coding sequences in the poplar genome identified 39 FLcDNAs that likely localize to gaps in the current genome sequence assembly. Another 173 FLcDNAs mapped to the genome sequence but were not included among the previously predicted genes in the poplar genome. Comparative sequence analysis against Arabidopsis thaliana and other species in the non-redundant database of GenBank revealed that 11.5% of the poplar FLcDNAs display no significant sequence similarity to other plant proteins. By mapping the poplar FLcDNAs against transcriptome data previously obtained with a 15.5 K cDNA microarray, we identified 153 FLcDNA clones for genes that were differentially expressed in

  19. Symplastic phloem loading in poplar.

    PubMed

    Zhang, Cankui; Han, Lu; Slewinski, Thomas L; Sun, Jianlei; Zhang, Jing; Wang, Zeng-Yu; Turgeon, Robert

    2014-09-01

    Sap is driven through phloem sieve tubes by an osmotically generated pressure gradient between source and sink tissues. In many plants, source pressure results from thermodynamically active loading in which energy is used to transfer sucrose (Suc) from mesophyll cells to the phloem of leaf minor veins against a concentration gradient. However, in some species, almost all trees, correlative evidence suggests that sugar migrates passively through plasmodesmata from mesophyll cells into the sieve elements. The possibility of alternate loading mechanisms has important ramifications for the regulation of phloem transport and source-sink interactions. Here, we provide experimental evidence that, in gray poplar (Populus tremula × Populus alba), Suc enters the phloem through plasmodesmata. Transgenic plants were generated with yeast invertase in the cell walls to prevent Suc loading by this route. The constructs were driven either by the constitutive 35S promoter or the minor vein-specific galactinol synthase promoter. Transgenic plants grew at the same rate as the wild type without symptoms of loading inhibition, such as accumulation of carbohydrates or leaf chlorosis. Rates of photosynthesis were normal. In contrast, alfalfa (Medicago sativa) plants, which have limited numbers of plasmodesmata between mesophyll and phloem, displayed typical symptoms of loading inhibition when transformed with the same DNA constructs. The results are consistent with passive loading of Suc through plasmodesmata in poplar. We also noted defense-related symptoms in leaves of transgenic poplar when the plants were abruptly exposed to excessively high temperatures, adding to evidence that hexose is involved in triggering the hypersensitive response.

  20. Apoplast proteome reveals that extracellular matrix contributes to multistress response in poplar

    PubMed Central

    2010-01-01

    Background Riverine ecosystems, highly sensitive to climate change and human activities, are characterized by rapid environmental change to fluctuating water levels and siltation, causing stress on their biological components. We have little understanding of mechanisms by which riverine plant species have developed adaptive strategies to cope with stress in dynamic environments while maintaining growth and development. Results We report that poplar (Populus spp.) has evolved a systems level "stress proteome" in the leaf-stem-root apoplast continuum to counter biotic and abiotic factors. To obtain apoplast proteins from P. deltoides, we developed pressure-chamber and water-displacement methods for leaves and stems, respectively. Analyses of 303 proteins and corresponding transcripts coupled with controlled experiments and bioinformatics demonstrate that poplar depends on constitutive and inducible factors to deal with water, pathogen, and oxidative stress. However, each apoplast possessed a unique set of proteins, indicating that response to stress is partly compartmentalized. Apoplast proteins that are involved in glycolysis, fermentation, and catabolism of sucrose and starch appear to enable poplar to grow normally under water stress. Pathogenesis-related proteins mediating water and pathogen stress in apoplast were particularly abundant and effective in suppressing growth of the most prevalent poplar pathogen Melampsora. Unexpectedly, we found diverse peroxidases that appear to be involved in stress-induced cell wall modification in apoplast, particularly during the growing season. Poplar developed a robust antioxidative system to buffer oxidation in stem apoplast. Conclusion These findings suggest that multistress response in the apoplast constitutes an important adaptive trait for poplar to inhabit dynamic environments and is also a potential mechanism in other riverine plant species. PMID:21114852

  1. Apoplast proteome reveals that extracellular matrix contributes to multi-stress response in poplar

    SciTech Connect

    Pechanova, Olga; Hsu, Chuan-Yu; Adams, Joshua P.; Pechan, Tibor; Vandervelde, Lindsay; Drnevich, Jenny; Jawdy, Sara; Adeli, Ardeshir; Suttle, Jeffrey; Lawrence, Amanda; Tschaplinski, Timothy J; Seguin, Armand; Yuceer, Cetin

    2010-01-01

    Riverine ecosystems, highly sensitive to climate change and human activities, are characterized by rapid environmental change to fluctuating water levels and siltation, causing stress on their biological components. We have little understanding of mechanisms by which riverine plant species have developed adaptive strategies to cope with stress in dynamic environments while maintaining growth and development. We report that poplar (Populus spp.) has evolved a systems level 'stress proteome' in the leaf-stem-root apoplast continuum to counter biotic and abiotic factors. To obtain apoplast proteins from P. deltoides, we developed pressure-chamber and water-displacement methods for leaves and stems, respectively. Analyses of 303 proteins and corresponding transcripts coupled with controlled experiments and bioinformatics demonstrate that poplar depends on constitutive and inducible factors to deal with water, pathogen, and oxidative stress. However, each apoplast possessed a unique set of proteins, indicating that response to stress is partly compartmentalized. Apoplast proteins that are involved in glycolysis, fermentation, and catabolism of sucrose and starch appear to enable poplar to grow normally under water stress. Pathogenesis-related proteins mediating water and pathogen stress in apoplast were particularly abundant and effective in suppressing growth of the most prevalent poplar pathogen Melampsora. Unexpectedly, we found diverse peroxidases that appear to be involved in stress-induced cell wall modification in apoplast, particularly during the growing season. Poplar developed a robust antioxidative system to buffer oxidation in stem apoplast. These findings suggest that multistress response in the apoplast constitutes an important adaptive trait for poplar to inhabit dynamic environments and is also a potential mechanism in other riverine plant species.

  2. In silico identification and characterization of N-Terminal acetyltransferase genes of poplar (Populus trichocarpa).

    PubMed

    Zhu, Hang-Yong; Li, Chun-Ming; Wang, Li-Feng; Bai, Hui; Li, Yan-Ping; Yu, Wen-Xi; Xia, De-An; Liu, Chang-Cai

    2014-01-27

    N-terminal acetyltransferase (Nats) complex is responsible for protein N-terminal acetylation (Nα-acetylation), which is one of the most common covalent modifications of eukaryotic proteins. Although genome-wide investigation and characterization of Nat catalytic subunits (CS) and auxiliary subunits (AS) have been conducted in yeast and humans they remain unexplored in plants. Here we report on the identification of eleven genes encoding eleven putative Nat CS polypeptides, and five genes encoding five putative Nat AS polypeptides in Populus. We document that the expansion of Nat CS genes occurs as duplicated blocks distributed across 10 of the 19 poplar chromosomes, likely only as a result of segmental duplication events. Based on phylogenetic analysis, poplar Nat CS were assigned to six subgroups, which corresponded well to the Nat CS types (CS of Nat A-F), being consistent with previous reports in humans and yeast. In silico analysis of microarray data showed that in the process of normal development of the poplar, their Nat CS and AS genes are commonly expressed at one relatively low level but share distinct tissue-specific expression patterns. This exhaustive survey of Nat genes in poplar provides important information to assist future studies on their functional role in poplar.

  3. ZmRFP1, the putative ortholog of SDIR1, encodes a RING-H2 E3 ubiquitin ligase and responds to drought stress in an ABA-dependent manner in maize.

    PubMed

    Xia, Zongliang; Liu, Quanjun; Wu, Jianyu; Ding, Junqiang

    2012-03-10

    Drought is one of the most important limiting factors in crop production. To identify genes required for the drought stress response in the cereal crop maize, a gene coding for RING-finger protein (ZmRFP1), which is highly responsive to PEG-induced drought stress, was isolated by mRNA differential display and rapid amplification of cDNA ends. The ZmRFP1 encodes a protein of 280 amino acids and contains a single C(3)H(2)C(3)-type RING motif in its C-terminal region. ZmRFP1 is an ortholog of Arabidopsis SDIR1 (salt- and drought-induced RING finger 1) (66% identity to AtSDIR1).The recombinant ZmRFP1 protein purified from Escherichia coli exhibited an in vitro E3 ubiquitin ligase activity. Real-time PCR analysis indicates that the transcript levels of ZmRFP1 were higher in aerial tissues including stems, leaves, tassels and immature ears, and were markedly up-regulated by drought stress, and exogenous ABA, but not by salt, heat and cold stresses. Transient expression of the green fluorescent protein (GFP)-ZmRFP1 fusion protein in onion cells revealed a plasma membrane localization of the protein. Further analysis of ZmRFP1 transcripts between an ABA-deficient transposon mutant viviparous14 (vp14) and its isogenic wild-type line W22 showed that ZmRFP1 transcript levels were induced significantly in the wild-type line under drought stress, but not in the mutant line VP14. These results indicate that ZmRFP1 responds to drought stress in an ABA-dependent way and is likely to function in the ubiquitin conjunction pathway. The ZmRFP1 might serve as a candidate gene in genetic improvement for drought tolerance engineering in cereal crop plants.

  4. The poplar basic helix-loop-helix transcription factor BEE3 – Like gene affects biomass production by enhancing proliferation of xylem cells in poplar

    SciTech Connect

    Noh, Seol Ah Choi, Young-Im Cho, Jin-Seong Lee, Hyoshin

    2015-06-19

    Brassinosteroids (BRs) play important roles in many aspects of plant growth and development, including regulation of vascular cambium activities and cell elongation. BR-induced BEE3 (brassinosteroid enhanced expression 3) is required for a proper BR response. Here, we identified a poplar (Populus alba × Populus glandulosa) BEE3-like gene, PagBEE3L, encoding a putative basic helix-loop-helix (bHLH)-type transcription factor. Expression of PagBEE3L was induced by brassinolide (BL). Transcripts of PagBEE3L were mainly detected in stems, with the internode having a low level of transcription and the node having a relatively higher level. The function of the PagBEE3L gene was investigated through phenotypic analyses with PagBEE3L-overexpressing (ox) transgenic lines. This work particularly focused on a potential role of PagBEE3L in stem growth and development of polar. The PagBEE3L-ox poplar showed thicker and longer stems than wild-type plants. The xylem cells from the stems of PagBEE3L-ox plants revealed remarkably enhanced proliferation, resulting in an earlier thickening growth than wild-type plants. Therefore, this work suggests that xylem development of poplar is accelerated in PagBEE3L-ox plants and PagBEE3L plays a role in stem growth by increasing the proliferation of xylem cells to promote the initial thickening growth of poplar stems. - Highlights: • We identify the BEE3-like gene form hybrid poplar (Populus alba × Populus glandulosa). • We examine effects of overexpression of PagBEE3L on growth in poplar. • We found that 35S:BEE3L transgenic plants showed more rapid growth than wild-type plants. • BEE3L protein plays an important role in the development of plant stem.

  5. Continuous steam hydrolysis of tulip poplar

    SciTech Connect

    Fieber, C.A.; Roberts, R.S.; Faass, G.S.; Muzzy, J.D.; Colcord, A.R.; Bery, M.K.

    1982-01-01

    The continuous hydrolysis of poplar chips by steam at 300-350 psi resulted in the separation of hemicellulose (I) cellulose and lignin components. The I fraction was readily depolymerised by steam to acetic acid, furfural, methanol, and xylose.

  6. Finding Fingerprints of Selection in Poplar Genomes

    SciTech Connect

    Tuskan, Gerald

    2014-10-02

    Jerry Tuskan of Oak Ridge National Laboratory and the DOE JGI talks about poplar trees as models for selective adaptation to an environment. This video complements a study published ahead online August 24, 2014 in Nature Genetics.

  7. Finding Fingerprints of Selection in Poplar Genomes

    ScienceCinema

    Tuskan, Gerald

    2016-07-12

    Jerry Tuskan of Oak Ridge National Laboratory and the DOE JGI talks about poplar trees as models for selective adaptation to an environment. This video complements a study published ahead online August 24, 2014 in Nature Genetics.

  8. Genotypic variations in the dynamics of metal concentrations in poplar leaves: a field study with a perspective on phytoremediation.

    PubMed

    Pottier, Mathieu; García de la Torre, Vanesa S; Victor, Cindy; David, Laure C; Chalot, Michel; Thomine, Sébastien

    2015-04-01

    Poplar is commonly used for phytoremediation of metal polluted soils. However, the high concentrations of trace elements present in leaves may return to soil upon leaf abscission. To investigate the mechanisms controlling leaf metal content, metal concentrations and expression levels of genes involved in metal transport were monitored at different developmental stages on leaves from different poplar genotypes growing on a contaminated field. Large differences in leaf metal concentrations were observed among genotypes. Whereas Mg was remobilized during senescence, Zn and Cd accumulation continued until leaf abscission in all genotypes. A positive correlation between Natural Resistance Associated Macrophage Protein 1 (NRAMP1) expression levels and Zn bio-concentration factors was observed. Principal component analyses of metal concentrations and gene expression levels clearly discriminated poplar genotypes. This study highlights a general absence of trace element remobilization from poplar leaves despite genotype specificities in the control of leaf metal homeostasis.

  9. Comparison of adhesive properties of water- and phosphate-buffer-washed cottonseed meals with cottonseed protein isolate on maple and poplar veneers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water- and phosphate buffer (35 mM Na2HPO4/NaH2PO4, pH 7.5)-washed cottonseed meals (abbreviated as WCM and BCM, respectively) could be low-cost and environmentally friendly protein-based adhesives as their preparation does not involve corrosive alkali and acid solutions that are needed for cottonse...

  10. Rhizosphere Competitiveness of Trichloroethylene-Degrading, Poplar-Colonizing Recombinant Bacteria

    PubMed Central

    Shim, Hojae; Chauhan, Sadhana; Ryoo, Doohyun; Bowers, Kally; Thomas, Stuart M.; Canada, Keith A.; Burken, Joel G.; Wood, Thomas K.

    2000-01-01

    Indigenous bacteria from poplar tree (Populus canadensis var. eugenei ‘Imperial Carolina’) and southern California shrub rhizospheres, as well as two tree-colonizing Rhizobium strains (ATCC 10320 and ATCC 35645), were engineered to express constitutively and stably toluene o-monooxygenase (TOM) from Burkholderia cepacia G4 by integrating the tom locus into the chromosome. The poplar and Rhizobium recombinant bacteria degraded trichloroethylene at a rate of 0.8 to 2.1 nmol/min/mg of protein and were competitive against the unengineered hosts in wheat and barley rhizospheres for 1 month (colonization occurred at a level of 1.0 × 105 to 23 × 105 CFU/cm of root). In addition, six of these recombinants colonized poplar roots stably and competitively with populations as large as 79% ± 12% of all rhizosphere bacteria after 28 days (0.2 × 105 to 31 × 105 CFU/cm of root). Furthermore, five of the most competitive poplar recombinants (e.g., Pb3-1 and Pb5-1, which were identified as Pseudomonas sp. strain PsK recombinants) retained the ability to express TOM for 29 days as 100% ± 0% of the recombinants detected in the poplar rhizosphere expressed TOM constitutively. PMID:11055909

  11. Polyphenol Oxidase from Hybrid Poplar. Cloning and Expression in Response to Wounding and Herbivory1

    PubMed Central

    Constabel, C. Peter; Yip, Lynn; Patton, Joseph J.; Christopher, Mary E.

    2000-01-01

    The inducible expression of polyphenol oxidase (PPO), a presumed antiherbivore enzyme, was examined in hybrid poplar (Populus trichocarpa × 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 reached peak levels at 16 and 24 h in wounded and unwounded leaves, respectively. Methyl jasmonate spray and feeding by forest tent caterpillar also induced PPO expression. The induction of PPO was strongest in the youngest four leaves, which were generally avoided by caterpillars in free feeding experiments. This wound- and herbivore-induced expression of PPO in hybrid poplar supports the defensive role of this protein against insect pests. PMID:10982443

  12. Polyphenol oxidase from hybrid poplar. Cloning and expression in response to wounding and herbivory.

    PubMed

    Constabel, C P; Yip, L; Patton, J J; Christopher, M E

    2000-09-01

    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 reached peak levels at 16 and 24 h in wounded and unwounded leaves, respectively. Methyl jasmonate spray and feeding by forest tent caterpillar also induced PPO expression. The induction of PPO was strongest in the youngest four leaves, which were generally avoided by caterpillars in free feeding experiments. This wound- and herbivore-induced expression of PPO in hybrid poplar supports the defensive role of this protein against insect pests.

  13. The complete chloroplast genome sequence of desert poplar (Populus euphratica).

    PubMed

    Zhang, Qun-jie; Gao, Li-zhi

    2016-01-01

    The complete chloroplast sequence of the desert poplar (Populus euphratica), a plant well-adapted to salt stress, was determined in this study. The genome consists of 156,766 bp containing a pair of inverted repeats (IRs) of 16,591 bp separated by a large single-copy region and a small single-copy region of 84,888 bp and 27,646 bp, respectively. The chloroplast genome contains 130 known genes, including 89 protein-coding genes, 8 ribosomal RNA genes, and 37 tRNA genes; 18 of these are located in the inverted repeat region.

  14. Biochemical response of hybrid black poplar tissue culture (Populus × canadensis) on water stress.

    PubMed

    Popović, B M; Štajner, D; Ždero-Pavlović, R; Tari, I; Csiszár, J; Gallé, Á; Poór, P; Galović, V; Trudić, B; Orlović, S

    2017-02-27

    In this study, poplar tissue culture (hybrid black poplar, M1 genotype) was subjected to water stress influenced by polyethyleneglycol 6000 (100 and 200 mOsm PEG 6000). The aim of the research was to investigate the biochemical response of poplar tissue culture on water deficit regime. Antioxidant status was analyzed including antioxidant enzymes, superoxide-dismutase (SOD), catalase (CAT), guiacol-peroxidase (GPx), glutathione-peroxidase (GSH-Px), glutathione-reductase, reduced glutathione, total phenol content, Ferric reducing antioxidant power and DPPH radical antioxidant power. Polyphenol oxidase and phenylalanine-ammonium-lyase were determined as enzymatic markers of polyphenol metabolism. Among oxidative stress parameters lipid peroxidation, carbonyl-proteins, hydrogen-peroxide, reactive oxygen species, nitric-oxide and peroxynitrite were determined. Proline, proline-dehydrogenase and glycinebetaine were measured also as parameters of water stress. Cell viability is finally determined as a biological indicator of osmotic stress. It was found that water stress induced reactive oxygen and nitrogen species and lipid peroxidation in leaves of hybrid black poplar and reduced cell viability. Antioxidant enzymes including SOD, GPx, CAT and GSH-Px were induced but total phenol content and antioxidant capacity were reduced by PEG 6000 mediated osmotic stress. The highest biochemical response and adaptive reaction was the increase of proline and GB especially by 200 mOsm PEG. While long term molecular analysis will be necessary to fully address the poplar potentials for water stress adaptation, our results on hybrid black poplar suggest that glycine-betaine, proline and PDH enzyme might be the most important markers of poplar on water stress and that future efforts should be focused on these markers and strategies to enhance their concentration in poplar.

  15. Circadian Rhythms of Isoprene Biosynthesis in Grey Poplar Leaves1

    PubMed Central

    Loivamäki, Maaria; Louis, Sandrine; Cinege, Gyöngyi; Zimmer, Ina; Fischbach, Robert J.; Schnitzler, Jörg-Peter

    2007-01-01

    Isoprene (2-methyl-1,3-butadiene) emission varies diurnally in different species. In poplar (Populus spp.), it has recently been shown that the gene encoding the synthesizing enzyme for isoprene, isoprene synthase (ISPS), displays diurnal variation in expression. Working on shoot cultures of Grey poplar (Populus × canescens) placed under a different light regime in phytochambers, we showed that these variations in PcISPS gene expression, measured by quantitative real-time polymerase chain reaction, are not only due to day-night changes, but also are linked to an internal circadian clock. Measurement of additional selected isoprenoid genes revealed that phytoene synthase (carotenoid pathway) displays similar fluctuations, whereas 1-deoxy-d-xylulose 5-phosphate reductoisomerase, possibly the first committed enzyme of the 1-deoxy-d-xylulose 5-phosphate pathway, only shows light regulation. On the protein level, it appeared that PcISPS activity and protein content became reduced under constant darkness, whereas under constant light, activity and protein content of this enzyme were kept high. In contrast, isoprene emission rates under continuous irradiation displayed circadian changes as is the case for gene expression of PcISPS. Furthermore, binding assays with Arabidopsis (Arabidopsis thaliana) late elongated hypocotyl, a transcription factor of Arabidopsis involved in circadian regulation, clearly revealed the presence of circadian-determining regulatory elements in the promoter region of PcISPS. PMID:17122071

  16. Expression analysis of LIM gene family in poplar, toward an updated phylogenetic classification

    PubMed Central

    2012-01-01

    Background Plant LIM domain proteins may act as transcriptional activators of lignin biosynthesis and/or as actin binding and bundling proteins. Plant LIM genes have evolved in phylogenetic subgroups differing in their expression profiles: in the whole plant or specifically in pollen. However, several poplar PtLIM genes belong to uncharacterized monophyletic subgroups and the expression patterns of the LIM gene family in a woody plant have not been studied. Findings In this work, the expression pattern of the twelve duplicated poplar PtLIM genes has been investigated by semi quantitative RT-PCR in different vegetative and reproductive tissues. As in other plant species, poplar PtLIM genes were widely expressed in the tree or in particular tissues. Especially, PtXLIM1a, PtXLIM1b and PtWLIM1b genes were preferentially expressed in the secondary xylem, suggesting a specific function in wood formation. Moreover, the expression of these genes and of the PtPLIM2a gene was increased in tension wood. Western-blot analysis confirmed the preferential expression of PtXLIM1a protein during xylem differentiation and tension wood formation. Genes classified within the pollen specific PLIM2 and PLIM2-like subgroups were all strongly expressed in pollen but also in cottony hairs. Interestingly, pairs of duplicated PtLIM genes exhibited different expression patterns indicating subfunctionalisations in specific tissues. Conclusions The strong expression of several LIM genes in cottony hairs and germinating pollen, as well as in xylem fibers suggests an involvement of plant LIM domain proteins in the control of cell expansion. Comparisons of expression profiles of poplar LIM genes with the published functions of closely related plant LIM genes suggest conserved functions in the areas of lignin biosynthesis, pollen tube growth and mechanical stress response. Based on these results, we propose a novel nomenclature of poplar LIM domain proteins. PMID:22339987

  17. Methylation of microRNA genes regulates gene expression in bisexual flower development in andromonoecious poplar.

    PubMed

    Song, Yuepeng; Tian, Min; Ci, Dong; Zhang, Deqiang

    2015-04-01

    Previous studies showed sex-specific DNA methylation and expression of candidate genes in bisexual flowers of andromonoecious poplar, but the regulatory relationship between methylation and microRNAs (miRNAs) remains unclear. To investigate whether the methylation of miRNA genes regulates gene expression in bisexual flower development, the methylome, microRNA, and transcriptome were examined in female and male flowers of andromonoecious poplar. 27 636 methylated coding genes and 113 methylated miRNA genes were identified. In the coding genes, 64.5% of the methylated reads mapped to the gene body region; by contrast, 60.7% of methylated reads in miRNA genes mainly mapped in the 5' and 3' flanking regions. CHH methylation showed the highest methylation levels and CHG showed the lowest methylation levels. Correlation analysis showed a significant, negative, strand-specific correlation of methylation and miRNA gene expression (r=0.79, P <0.05). The methylated miRNA genes included eight long miRNAs (lmiRNAs) of 24 nucleotides and 11 miRNAs related to flower development. miRNA172b might play an important role in the regulation of bisexual flower development-related gene expression in andromonoecious poplar, via modification of methylation. Gynomonoecious, female, and male poplars were used to validate the methylation patterns of the miRNA172b gene, implying that hyper-methylation in andromonoecious and gynomonoecious poplar might function as an important regulator in bisexual flower development. Our data provide a useful resource for the study of flower development in poplar and improve our understanding of the effect of epigenetic regulation on genes other than protein-coding genes.

  18. Genome analysis of poplar LRR-RLP gene clusters reveals RISP, a defense-related gene coding a candidate endogenous peptide elicitor

    PubMed Central

    Petre, Benjamin; Hacquard, Stéphane; Duplessis, Sébastien; Rouhier, Nicolas

    2014-01-01

    In plants, cell-surface receptors control immunity and development through the recognition of extracellular ligands. Leucine-rich repeat receptor-like proteins (LRR-RLPs) constitute a large multigene family of cell-surface receptors. Although this family has been intensively studied, a limited number of ligands has been identified so far, mostly because methods used for their identification and characterization are complex and fastidious. In this study, we combined genome and transcriptome analyses to describe the LRR-RLP gene family in the model tree poplar (Populus trichocarpa). In total, 82 LRR-RLP genes have been identified in P. trichocarpa genome, among which 66 are organized in clusters of up to seven members. In these clusters, LRR-RLP genes are interspersed by orphan, poplar-specific genes encoding small proteins of unknown function (SPUFs). In particular, the nine largest clusters of LRR-RLP genes (47 LRR-RLPs) include 71 SPUF genes that account for 59% of the non-LRR-RLP gene content within these clusters. Forty-four LRR-RLP and 55 SPUF genes are expressed in poplar leaves, mostly at low levels, except for members of some clusters that show higher and sometimes coordinated expression levels. Notably, wounding of poplar leaves strongly induced the expression of a defense SPUF gene named Rust-Induced Secreted protein (RISP) that has been previously reported as a marker of poplar defense responses. Interestingly, we show that the RISP-associated LRR-RLP gene is highly expressed in poplar leaves and slightly induced by wounding. Both gene promoters share a highly conserved region of ~300 nucleotides. This led us to hypothesize that the corresponding pair of proteins could be involved in poplar immunity, possibly as a ligand/receptor couple. In conclusion, we speculate that some poplar SPUFs, such as RISP, represent candidate endogenous peptide ligands of the associated LRR-RLPs and we discuss how to investigate further this hypothesis. PMID:24734035

  19. Aquaporins and leaf hydraulics: poplar sheds new light.

    PubMed

    Lopez, David; Venisse, Jean-Stéphane; Fumanal, Boris; Chaumont, François; Guillot, Esther; Daniels, Mark J; Cochard, Hervé; Julien, Jean-Louis; Gousset-Dupont, Aurélie

    2013-12-01

    To help understand leaf hydraulic conductance (Kleaf) modulation under high irradiance, well-watered poplars (Populus trichocarpa Torr. & Gray ex Hook and Populus nigra L.) were studied diurnally at molecular and ecophysiological scales. Transcriptional and translational modulations of plasma membrane intrinsic protein (PIP) aquaporins were evaluated in leaf samples during diurnal time courses. Among the 15 poplar PIP genes, a subset of two PIP1s and seven PIP2s are precociously induced within the first hour of the photoperiod concomitantly with a Kleaf increase. Since expression patterns were cyclic and reproducible over several days, we hypothesized that endogenous signals could be involved in PIP transcriptional regulation. To address this question, plants were submitted to forced darkness during their subjective photoperiod and compared with their control counterparts, which showed that some PIP1s and PIP2s have circadian regulation while others did not. Promoter analysis revealed that a large number of hormone, light, stress response and circadian elements are present. Finally, involvement of aquaporins is supported by the reduction of Kleaf by HgCl2 treatment.

  20. Poplar trees for phytoremediation of high levels of nitrate and applications in bioenergy.

    PubMed

    Castro-Rodríguez, Vanessa; García-Gutiérrez, Angel; Canales, Javier; Cañas, Rafael A; Kirby, Edward G; Avila, Concepción; Cánovas, Francisco M

    2016-01-01

    The utilization of high amounts of nitrate fertilizers for crop yield leads to nitrate pollution of ground and surface waters. In this study, we report the assimilation and utilization of nitrate luxuriant levels, 20 times more than the highest N fertilizer application in Europe, by transgenic poplars overexpressing a cytosolic glutamine synthetase (GS1). In comparison with the wild-type controls, transgenic plants grown under high N levels exhibited increased biomass (171.6%) and accumulated higher levels of proteins, chlorophylls and total sugars such as glucose, fructose and sucrose. These plants also exhibited greater nitrogen-use efficiency particularly in young leaves, suggesting that they are able to translocate most of the resources to the above-ground part of the plant to produce biomass. The transgenic poplar transcriptome was greatly affected in response to N availability with 1237 genes differentially regulated in high N, while only 632 genes were differentially expressed in untransformed plants. Many of these genes are essential in the adaptation and response against N excess and include those involved in photosynthesis, cell wall formation and phenylpropanoid biosynthesis. Cellulose production in the transgenic plants was fivefold higher than in control plants, indicating that transgenic poplars represent a potential feedstock for applications in bioenergy. In conclusion, our results show that GS transgenic poplars can be used not only for improving growth and biomass production but also as an important resource for potential phytoremediation of nitrate pollution.

  1. Diversity of arthropod community in transgenic poplar-cotton ecosystems.

    PubMed

    Zhang, D J; Lu, Z Y; Liu, J X; Li, C L; Yang, M S

    2015-12-02

    Poplar-cotton agro-ecosystems are the main agricultural planting modes of plain cotton fields in China. Here, we performed a systematic survey of the diversity and population of arthropod communities in four different combination of poplar-cotton eco-systems, including I) non-transgenic poplar and non-transgenic cotton fields; II) non-transgenic poplar and transgenic cotton fields [Bacillus thuringiensis (Bt) cotton]; III) Bt transgenic poplar (high insect resistant strain Pb29) and non-transgenic cotton; and IV) transgenic poplar and transgenic cotton fields, over a period of 3 years. Based on the statistical methods used to investigate community ecology, the effects of transgenic ecosystems on the whole structure of the arthropod community, on the structure of arthropods in the nutritive layer, and on the similarity of arthropod communities were evaluated. The main results were as follows: the transgenic poplar-cotton ecosystem has a stronger inhibitory effect on insect pests and has no impact on the structure of the arthropod community, and therefore, maintains the diversity of the arthropod community. The character index of the community indicated that the structure of the arthropod community of the transgenic poplar-cotton ecosystem was better than that of the poplar-cotton ecosystem, and that system IV had the best structure. As for the abundance of nutritional classes, the transgenic poplar-cotton ecosystem was also better than that of the non-transgenic poplar-cotton ecosystem. The cluster analysis and similarity of arthropod communities between the four different transgenic poplar-cotton ecosystems illustrated that the structure of the arthropod community excelled in the small sample of the transgenic poplar-cotton ecosystems.

  2. Isolation and characterization of galactinol synthases from hybrid poplar

    PubMed Central

    Unda, Faride; Canam, Thomas; Preston, Lindsay; Mansfield, Shawn D.

    2012-01-01

    The raffinose family of oligosaccharides (RFOs) serve as transport carbohydrates in the phloem, storage compounds in sink tissues, and putative biological agents to combat both abiotic and biotic stress in several plant species. To investigate further the functional roles of this class of compounds in trees, two cDNAs encoding galactinol synthase (GolS, EC 2.4.1.123), which catalyses the first step in the biosynthesis of RFOs, were identified and cloned from hybrid poplar (Populus alba×grandidentata). Phylogenetic analyses of the Populus GolS isoforms with other known GolS proteins suggested a putative role for these enzymes during biotic or abiotic stress in hybrid poplar. The predicted protein sequences of both isoforms (Pa×gGolSI and Pa×gGolSII) showed characteristics of GolS proteins from other species, including a serine phosphorylation site and the ASAAP pentapeptide hydrophobic domain. Kinetic analyses of recombinant Pa×gGolSI and Pa×gGolSII resulted in Km values for UPD-galactose of 0.80 and 0.65 mM and Vmax values of 657.5 and 1245 nM min−1, respectively. Pa×gGolSI inherently possessed a broader pH and temperature range when compared with Pa×gGolSII. Interestingly, spatial and temporal expression analyses revealed that Pa×gGolSII transcript levels varied seasonally, while Pa×gGolSI did not, implying temperature-regulated transcriptional control of this gene in addition to the observed thermosensitivity of the respective enzyme. This evidence suggested that Pa×gGolSI may be involved in basic metabolic activities such as storage, while Pa×gGolSII is probably involved in seasonal mobilization of carbohydrates. PMID:22197892

  3. Isolation and expression analysis of low temperature-induced genes in white poplar (Populus alba).

    PubMed

    Maestrini, Pierluigi; Cavallini, Andrea; Rizzo, Milena; Giordani, Tommaso; Bernardi, Rodolfo; Durante, Mauro; Natali, Lucia

    2009-09-15

    Poplar is an important crop and a model system to understand molecular processes of growth, development and responses to environmental stimuli in trees. In this study, we analyzed gene expression in white poplar (Populus alba) plants subjected to chilling. Two forward suppression-subtractive-hybridization libraries were constructed from P. alba plants exposed to low non-freezing temperature for 6 or 48h. Hundred and sixty-two cDNAs, 54 from the 6-h library and 108 from the 48-h library, were obtained. Isolated genes belonged to six categories of genes, specifically those that: (i) encode stress and defense proteins; (ii) are involved in signal transduction; (iii) are related to regulation of gene expression; (iv) encode proteins involved in cell cycle and DNA processing; (v) encode proteins involved in metabolism and energetic processes; and (vi) are involved in protein fate. Different expression patterns at 3, 6, 12, 24, 48h at 4 degrees C and after a recovery of 24h at 20 degrees C were observed for isolated genes, as expected according to the class in which the gene putatively belongs. Forty-four of 162 genes contained DRE/LTRE cis-elements in the 5' proximal promoter of their orthologs in Populus trichocarpa, suggesting that they putatively belong to the CBF regulon. The results contribute new data to the list of possible candidate genes involved in cold response in poplar.

  4. 6. GENERAL VIEW EAST FROM ROOFTOP OF POPLAR FOREST TOWARDS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. GENERAL VIEW EAST FROM ROOFTOP OF POPLAR FOREST TOWARDS SUMMER KITCHEN (FOREGROUND) AND DAIRY; CHIMNEY OF SOUTH TENANT HOUSE BARELY VISIBLE THROUGH TREES; EAST PRIVY RARELY VISIBLE OVER EAST MOUND (1987) - Poplar Forest, Summer Kitchen, State Route 661, Forest, Bedford County, VA

  5. Morphological and molecular characterization of two Aphelenchoides from poplar leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During a long-term, large network study of the ecology of plant endophytes in native habitats, various nematodes were found. Two poplar species, Populus angustifolia (narrowleaf cottonwood) and P. trichocarpa (black poplar) represent important ecological and genomic models now used in ongoing plant...

  6. Functional Divergence of Poplar Histidine-Aspartate Kinase HK1 Paralogs in Response to Osmotic Stress

    PubMed Central

    Héricourt, François; Chefdor, Françoise; Djeghdir, Inès; Larcher, Mélanie; Lafontaine, Florent; Courdavault, Vincent; Auguin, Daniel; Coste, Franck; Depierreux, Christiane; Tanigawa, Mirai; Maeda, Tatsuya; Glévarec, Gaëlle; Carpin, Sabine

    2016-01-01

    Previous works have shown the existence of protein partnerships belonging to a MultiStep Phosphorelay (MSP) in Populus putatively involved in osmosensing. This study is focused on the identification of a histidine-aspartate kinase, HK1b, paralog of HK1a. The characterization of HK1b showed its ability to homo- and hetero-dimerize and to interact with a few Histidine-containing Phosphotransfer (HPt) proteins, suggesting a preferential partnership in poplar MSP linked to drought perception. Furthermore, determinants for interaction specificity between HK1a/1b and HPts were studied by mutagenesis analysis, identifying amino acids involved in this specificity. The HK1b expression analysis in different poplar organs revealed its co-expression with three HPts, reinforcing the hypothesis of partnership participation in the MSP in planta. Moreover, HK1b was shown to act as an osmosensor with kinase activity in a functional complementation assay of an osmosensor deficient yeast strain. These results revealed that HK1b showed a different behaviour for canonical phosphorylation of histidine and aspartate residues. These phosphorylation modularities of canonical amino acids could explain the improved osmosensor performances observed in yeast. As conserved duplicates reflect the selective pressures imposed by the environmental requirements on the species, our results emphasize the importance of HK1 gene duplication in poplar adaptation to drought stress. PMID:27941652

  7. Functional Divergence of Poplar Histidine-Aspartate Kinase HK1 Paralogs in Response to Osmotic Stress.

    PubMed

    Héricourt, François; Chefdor, Françoise; Djeghdir, Inès; Larcher, Mélanie; Lafontaine, Florent; Courdavault, Vincent; Auguin, Daniel; Coste, Franck; Depierreux, Christiane; Tanigawa, Mirai; Maeda, Tatsuya; Glévarec, Gaëlle; Carpin, Sabine

    2016-12-08

    Previous works have shown the existence of protein partnerships belonging to a MultiStep Phosphorelay (MSP) in Populus putatively involved in osmosensing. This study is focused on the identification of a histidine-aspartate kinase, HK1b, paralog of HK1a. The characterization of HK1b showed its ability to homo- and hetero-dimerize and to interact with a few Histidine-containing Phosphotransfer (HPt) proteins, suggesting a preferential partnership in poplar MSP linked to drought perception. Furthermore, determinants for interaction specificity between HK1a/1b and HPts were studied by mutagenesis analysis, identifying amino acids involved in this specificity. The HK1b expression analysis in different poplar organs revealed its co-expression with three HPts, reinforcing the hypothesis of partnership participation in the MSP in planta. Moreover, HK1b was shown to act as an osmosensor with kinase activity in a functional complementation assay of an osmosensor deficient yeast strain. These results revealed that HK1b showed a different behaviour for canonical phosphorylation of histidine and aspartate residues. These phosphorylation modularities of canonical amino acids could explain the improved osmosensor performances observed in yeast. As conserved duplicates reflect the selective pressures imposed by the environmental requirements on the species, our results emphasize the importance of HK1 gene duplication in poplar adaptation to drought stress.

  8. Effector-Mining in the Poplar Rust Fungus Melampsora larici-populina Secretome

    PubMed Central

    Lorrain, Cécile; Hecker, Arnaud; Duplessis, Sébastien

    2015-01-01

    The poplar leaf rust fungus, Melampsora larici-populina has been established as a tree-microbe interaction model. Understanding the molecular mechanisms controlling infection by pathogens appears essential for durable management of tree plantations. In biotrophic plant-parasites, effectors are known to condition host cell colonization. Thus, investigation of candidate secreted effector proteins (CSEPs) is a major goal in the poplar–poplar rust interaction. Unlike oomycetes, fungal effectors do not share conserved motifs and candidate prediction relies on a set of a priori criteria established from reported bona fide effectors. Secretome prediction, genome-wide analysis of gene families and transcriptomics of M. larici-populina have led to catalogs of more than a thousand secreted proteins. Automatized effector-mining pipelines hold great promise for rapid and systematic identification and prioritization of CSEPs for functional characterization. In this review, we report on and discuss the current status of the poplar rust fungus secretome and prediction of candidate effectors from this species. PMID:26697026

  9. Dual targeted poplar ferredoxin NADP(+) oxidoreductase interacts with hemoglobin 1.

    PubMed

    Jokipii-Lukkari, Soile; Kastaniotis, Alexander J; Parkash, Vimal; Sundström, Robin; Leiva-Eriksson, Nélida; Nymalm, Yvonne; Blokhina, Olga; Kukkola, Eija; Fagerstedt, Kurt V; Salminen, Tiina A; Läärä, Esa; Bülow, Leif; Ohlmeier, Steffen; Hiltunen, J Kalervo; Kallio, Pauli T; Häggman, Hely

    2016-06-01

    Previous reports have connected non-symbiotic and truncated hemoglobins (Hbs) to metabolism of nitric oxide (NO), an important signalling molecule involved in wood formation. We have studied the capability of poplar (Populus tremula × tremuloides) Hbs PttHb1 and PttTrHb proteins alone or with a flavin-protein reductase to relieve NO cytotoxicity in living cells. Complementation tests in a Hb-deficient, NO-sensitive yeast (Saccharomyces cerevisiae) Δyhb1 mutant showed that neither PttHb1 nor PttTrHb alone protected cells against NO. To study the ability of Hbs to interact with a reductase, ferredoxin NADP(+) oxidoreductase PtthFNR was characterized by sequencing and proteomics. To date, by far the greatest number of the known dual-targeted plant proteins are directed to chloroplasts and mitochondria. We discovered a novel variant of hFNR that lacks the plastid presequence and resides in cytosol. The coexpression of PttHb1 and PtthFNR partially restored NO resistance of the yeast Δyhb1 mutant, whereas PttTrHb coexpressed with PtthFNR failed to rescue growth. YFP fusion proteins confirmed the interaction between PttHb1 and PtthFNR in plant cells. The structural modelling results indicate that PttHb1 and PtthFNR are able to interact as NO dioxygenase. This is the first report on dual targeting of central plant enzyme FNR to plastids and cytosol.

  10. Patterns of genomic variation in the poplar rust fungus Melampsora larici-populina identify pathogenesis-related factors

    PubMed Central

    Persoons, Antoine; Morin, Emmanuelle; Delaruelle, Christine; Payen, Thibaut; Halkett, Fabien; Frey, Pascal; De Mita, Stéphane; Duplessis, Sébastien

    2014-01-01

    Melampsora larici-populina is a fungal pathogen responsible for foliar rust disease on poplar trees, which causes damage to forest plantations worldwide, particularly in Northern Europe. The reference genome of the isolate 98AG31 was previously sequenced using a whole genome shotgun strategy, revealing a large genome of 101 megabases containing 16,399 predicted genes, which included secreted protein genes representing poplar rust candidate effectors. In the present study, the genomes of 15 isolates collected over the past 20 years throughout the French territory, representing distinct virulence profiles, were characterized by massively parallel sequencing to assess genetic variation in the poplar rust fungus. Comparison to the reference genome revealed striking structural variations. Analysis of coverage and sequencing depth identified large missing regions between isolates related to the mating type loci. More than 611,824 single-nucleotide polymorphism (SNP) positions were uncovered overall, indicating a remarkable level of polymorphism. Based on the accumulation of non-synonymous substitutions in coding sequences and the relative frequencies of synonymous and non-synonymous polymorphisms (i.e., PN/PS), we identify candidate genes that may be involved in fungal pathogenesis. Correlation between non-synonymous SNPs in genes encoding secreted proteins (SPs) and pathotypes of the studied isolates revealed candidate genes potentially related to virulences 1, 6, and 8 of the poplar rust fungus. PMID:25309551

  11. Interaction of nitrogen nutrition and salinity in Grey poplar (Populus tremula x alba).

    PubMed

    Ehlting, B; Dluzniewska, P; Dietrich, H; Selle, A; Teuber, M; Hänsch, R; Nehls, U; Polle, A; Schnitzler, J-P; Rennenberg, H; Gessler, A

    2007-07-01

    Salinity represents an increasing environmental problem in managed ecosystems. Populus spp. is widely used for wood production by short-rotation forestry in fertilized plantations and can be grown on saline soil. Because N fertilization plays an important role in salt tolerance, we analysed Grey poplar (Populus tremula x alba, syn. Populus canescens) grown with either 1 mM nitrate or ammonium subjected to moderate 75 mM NaCl. The impact of N nutrition on amelioration of salt tolerance was analysed on different levels of N metabolism such as N uptake, assimilation and N (total N, proteins and amino compounds) accumulation. Na concentration increased in all tissues over time of salt exposure. The N nutrition-dependent effects of salt exposure were more intensive in roots than in leaves. Application of salt reduced root increment as well as stem height increase and, at the same time, increased the concentration of total amino compounds more intensively in roots of ammonium-fed plants. In leaves, salt treatment increased concentrations of total N more intensively in nitrate-fed plants and concentrations of amino compounds independently of N nutrition. The major changes in N metabolism of Grey poplar exposed to moderate salt concentrations were detected in the significant increase of amino acid concentrations. The present results indicate that N metabolism of Grey poplar exposed to salt performed better when the plants were fed with nitrate instead of ammonium as sole N source. Therefore, nitrate fertilization of poplar plantations grown on saline soil should be preferred.

  12. Cytokinin signaling regulates cambial development in poplar.

    PubMed

    Nieminen, Kaisa; Immanen, Juha; Laxell, Marjukka; Kauppinen, Leila; Tarkowski, Petr; Dolezal, Karel; Tähtiharju, Sari; Elo, Annakaisa; Decourteix, Mélanie; Ljung, Karin; Bhalerao, Rishikesh; Keinonen, Kaija; Albert, Victor A; Helariutta, Ykä

    2008-12-16

    Although a substantial proportion of plant biomass originates from the activity of vascular cambium, the molecular basis of radial plant growth is still largely unknown. To address whether cytokinins are required for cambial activity, we studied cytokinin signaling across the cambial zones of 2 tree species, poplar (Populus trichocarpa) and birch (Betula pendula). We observed an expression peak for genes encoding cytokinin receptors in the dividing cambial cells. We reduced cytokinin levels endogenously by engineering transgenic poplar trees (P. tremula x tremuloides) to express a cytokinin catabolic gene, Arabidopsis CYTOKININ OXIDASE 2, under the promoter of a birch CYTOKININ RECEPTOR 1 gene. Transgenic trees showed reduced concentration of a biologically active cytokinin, correlating with impaired cytokinin responsiveness. In these trees, both apical and radial growth was compromised. However, radial growth was more affected, as illustrated by a thinner stem diameter than in WT at same height. To dissect radial from apical growth inhibition, we performed a reciprocal grafting experiment. WT scion outgrew the diameter of transgenic stock, implicating cytokinin activity as a direct determinant of radial growth. The reduced radial growth correlated with a reduced number of cambial cell layers. Moreover, expression of a cytokinin primary response gene was dramatically reduced in the thin-stemmed transgenic trees. Thus, a reduced level of cytokinin signaling is the primary basis for the impaired cambial growth observed. Together, our results show that cytokinins are major hormonal regulators required for cambial development.

  13. Overexpression of Poplar Pyrabactin Resistance-Like Abscisic Acid Receptors Promotes Abscisic Acid Sensitivity and Drought Resistance in Transgenic Arabidopsis.

    PubMed

    Yu, Jingling; Yang, Lei; Liu, Xiaobing; Tang, Renjie; Wang, Yuan; Ge, Haiman; Wu, Mengting; Zhang, Jiang; Zhao, Fugeng; Luan, Sheng; Lan, Wenzhi

    2016-01-01

    Drought stress is an important environmental factor limiting productivity of plants, especially fast growing species with high water consumption like poplar. Abscisic acid (ABA) is a phytohormone that positively regulates seed dormancy and drought resistance. The PYR1 (Pyrabactin Resistance 1)/ PYRL (PYR-Like)/ RCAR (Regulatory Component of ABA Receptor) (PYR/PYL/RCAR) ABA receptor family has been identified and widely characterized in Arabidopsis thaliana. However, their functions in poplars remain unknown. Here, we report that 2 of 14 PYR/PYL/RCAR orthologues in poplar (Populus trichocarpa) (PtPYRLs) function as a positive regulator of the ABA signal transduction pathway. The Arabidopsis transient expression and yeast two-hybrid assays showed the interaction among PtPYRL1 and PtPYRL5, a clade A protein phosphatase 2C, and a SnRK2, suggesting that a core signalling complex for ABA signaling pathway exists in poplars. Phenotypic analysis of PtPYRL1 and PtPYRL5 transgenic Arabidopsis showed that these two genes positively regulated the ABA responses during the seed germination. More importantly, the overexpression of PtPYRL1 and PtPYRL5 substantially improved ABA sensitivity and drought stress tolerance in transgenic plants. In summary, we comprehensively uncovered the properties of PtPYRL1 and PtPYRL5, which might be good target genes to genetically engineer drought-Resistant plants.

  14. Overexpression of Poplar Pyrabactin Resistance-Like Abscisic Acid Receptors Promotes Abscisic Acid Sensitivity and Drought Resistance in Transgenic Arabidopsis

    PubMed Central

    Liu, Xiaobing; Tang, Renjie; Wang, Yuan; Ge, Haiman; Wu, Mengting; Zhang, Jiang; Zhao, Fugeng; Luan, Sheng; Lan, Wenzhi

    2016-01-01

    Drought stress is an important environmental factor limiting productivity of plants, especially fast growing species with high water consumption like poplar. Abscisic acid (ABA) is a phytohormone that positively regulates seed dormancy and drought resistance. The PYR1 (Pyrabactin Resistance 1)/ PYRL (PYR-Like)/ RCAR (Regulatory Component of ABA Receptor) (PYR/PYL/RCAR) ABA receptor family has been identified and widely characterized in Arabidopsis thaliana. However, their functions in poplars remain unknown. Here, we report that 2 of 14 PYR/PYL/RCAR orthologues in poplar (Populus trichocarpa) (PtPYRLs) function as a positive regulator of the ABA signal transduction pathway. The Arabidopsis transient expression and yeast two-hybrid assays showed the interaction among PtPYRL1 and PtPYRL5, a clade A protein phosphatase 2C, and a SnRK2, suggesting that a core signalling complex for ABA signaling pathway exists in poplars. Phenotypic analysis of PtPYRL1 and PtPYRL5 transgenic Arabidopsis showed that these two genes positively regulated the ABA responses during the seed germination. More importantly, the overexpression of PtPYRL1 and PtPYRL5 substantially improved ABA sensitivity and drought stress tolerance in transgenic plants. In summary, we comprehensively uncovered the properties of PtPYRL1 and PtPYRL5, which might be good target genes to genetically engineer drought-Resistant plants. PMID:27992471

  15. Comparative physiological and proteomic responses to drought stress in two poplar species originating from different altitudes.

    PubMed

    Yang, Fan; Wang, Yong; Miao, Ling-Feng

    2010-08-01

    Cuttings of Populus kangdingensis C. Wang et Tung and Populus cathayana Rehder were examined during a single growing season in a greenhouse for comparative analysis of their physiological and proteomic responses to drought stress. The said species originate from high and low altitudes, respectively, of the eastern Himalaya. Results revealed that the adaptive responses to drought stress vary between the two poplar species. As a consequence of drought stress, the stem height increment and leaf number increment are more significantly inhibited in P. cathayana compared with P. kangdingensis. On the other hand, in response to drought stress, more significant cellular damages such as reduction in leaf relative water content and CO(2) assimilation rate, increments in the contents of malondialdehyde and hydrogen peroxide and downregulation or degradation of proteins related to photosynthesis occur in P. cathayana compared with P. kangdingensis. On the other hand, P. kangdingensis can cope better with the negative impact on the entire regulatory network. This includes more efficient increases in content of solute sugar, soluble protein and free proline and activities of antioxidant enzymes, as well as specific expressions of certain proteins related to protein processing, redox homeostasis and sugar metabolism. Morphological consequences as well as physiological and proteomic responses to drought stress between species revealed that P. kangdingensis originating from a high altitude manifest stronger drought adaptation than did P. cathayana originating from a low altitude. Functions of various proteins identified by proteomic experiment are related with physiological phenomena. Physiological and proteomic responses to drought stress in poplar may work cooperatively to establish a new cellular homeostasis, allowing poplar to develop a certain level of drought tolerance.

  16. 8. EXTERIOR VIEW OF THE BARNES BUILDING FROM POPLAR STREET, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. EXTERIOR VIEW OF THE BARNES BUILDING FROM POPLAR STREET, FACING NORTHEAST. CITY AUDITORIUM (BACKGROUND RIGHT) AND THE SHRINE TEMPLE (BACKGROUND LEFT). - Barnes Building, 477 Cotton Avenue, Macon, Bibb County, GA

  17. Poplar and its bacterial endophytes: coexistence and harmony

    SciTech Connect

    van der Lelie, D.; Taghavi, S.; Monchy, S.; Schwender, J.; Miller, L.; Ferrieri, R.; Rogers, A.; Zhu, W.; Weyens, N.; Vangronsveld, J.; Newman, L.

    2009-09-01

    Associations between plants and microorganisms are very complex and are the subject of an increasing number of studies. Here, we specifically address the relationship between poplar and its endophytic bacteria. The role and importance of endophytic bacteria in growth and development of their host plants is still underestimated. However, since many endophytes have a beneficial effect on their host, an improved understanding of the interaction between poplar and its endophytic bacteria has the potential to provide major breakthroughs that will improve the productivity of poplar. Endophytic bacteria can improve plant growth and development in a direct or indirect way. Direct plant growth promoting mechanisms may involve nitrogen fixation, production of plant growth regulators such as auxins, cytokinins and gibberellins, and suppression of stress ethylene synthesis by 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. Endophytic bacteria can indirectly benefit the plant by preventing the growth or activity of plant pathogens through competition for space and nutrients, antibiosis, production of hydrolytic enzymes, inhibition of pathogen-produced enzymes or toxins, and through systemic induction of plant defense mechanisms. Examples of applications for custom endophyte-host partnerships include improved productivity and establishment of poplar trees on marginal soils and the phytoremediation of contaminated soils and groundwater. A systems biology approach to understand the synergistic interactions between poplar and its beneficial endophytic bacteria represents an important field of research, which is facilitated by the recent sequencing of the genomes of poplar and several of its endophytic bacteria.

  18. Continuous steam hydrolysis of tulip poplar

    SciTech Connect

    Fieber, C.; Colcord, A.R.; Faass, S.; Muzzy, J.D.; Roberts, R.S.

    1982-08-01

    To produce ethanol from hardwood it is desirable to fractionate the hardwood in order to produce a relatively pure cellulosic pulp for dilute acid hydrolysis. An experimental investigation of continuous steam hydrolysis of tulip poplar wood chips indicates that over 90% of the lignin present can be extracted by 0.1N sodium hydroxide, resulting in a cellulose pulp containing over 90% hexosan. The study was performed using a Stake Technology, Ltd., continuous digester rated at one oven dry ton per hour of wood chips. The yields of hexosans, hexoses, xylan, xylose, lignin, furfural, acetic acid and methanol were determined as a function of residence time and steam pressure in the digester. The information provides a basis for establishing a material and energy balance for a hardwood to ethanol plant.

  19. Genomic insights into salt adaptation in a desert poplar

    SciTech Connect

    Ma, Tao; Wang, Junyi; Zhou, Gongke; Yue, Zhen; Hu, Quanjun; Chen, Yan; Liu, Bingbing; Qiu, Qiang; Wang, Zhuo; Zhang, Jian; Wang, Kun; Jiang, Dechun; Gou, Caiyun; Yu, Lili; Zhan, Dongliang; Zhou, Ran; Luo, Wenchun; Ma, Hui; Yang, Yongzhi; Pan, Shengkai; Fang, Dongming; Luo, Yadan; Wang, Xia; Wang, Gaini; Wang, Juan; Wang, Qian; Lu, Xu; Chen, Zhe; Liu, Jinchao; Lu, Yao; Yin, Ye; Yang, Huanming; Abbott, Richard J.; Wu, Yuxia; Wan, Dongshi; Li, Jia; Yin, Tongming; Lascoux, Martin; DiFazio, Stephen P.; Tuskan, Gerald A.; Wang, Jun; Jianquan, Liu

    2013-01-01

    Despite the high economic and ecological importance of forests, our knowledge of the genomic evolution of trees under salt stress remains very limited. Here we report the genome sequence of the desert poplar, Populus euphratica, which exhibits high tolerance to sa lt stress. Its genome is very similar and collinear to that of the closely related mesophytic congener, P trichocarpa. However, we find that several gene families likely to be involved in tolerance to salt stress contain significantly more gene copies within the P euphratica lineage. Furthermore, genes showing evidence of positive selection are significantly enriched in functional categories related to salt stress. Some of these genes, and others within the same categories, are significantly upregulated under salt stress relative to their expression in another salt-sensitive poplar. Our results provide an important background for understanding tree adaptation to salt stress and facilitating the genetic improvement of cultivated poplars for saline soils.

  20. S-Nitroso-Proteome in Poplar Leaves in Response to Acute Ozone Stress

    PubMed Central

    Vanzo, Elisa; Ghirardo, Andrea; Merl-Pham, Juliane; Lindermayr, Christian; Heller, Werner; Hauck, Stefanie M.; Durner, Jörg; Schnitzler, Jörg-Peter

    2014-01-01

    Protein S-nitrosylation, the covalent binding of nitric oxide (NO) to protein cysteine residues, is one of the main mechanisms of NO signaling in plant and animal cells. Using a combination of the biotin switch assay and label-free LC-MS/MS analysis, we revealed the S-nitroso-proteome of the woody model plant Populus x canescens. Under normal conditions, constitutively S-nitrosylated proteins in poplar leaves and calli comprise all aspects of primary and secondary metabolism. Acute ozone fumigation was applied to elicit ROS-mediated changes of the S-nitroso-proteome. This treatment changed the total nitrite and nitrosothiol contents of poplar leaves and affected the homeostasis of 32 S-nitrosylated proteins. Multivariate data analysis revealed that ozone exposure negatively affected the S-nitrosylation status of leaf proteins: 23 proteins were de-nitrosylated and 9 proteins had increased S-nitrosylation content compared to the control. Phenylalanine ammonia-lyase 2 (log2[ozone/control] = −3.6) and caffeic acid O-methyltransferase (−3.4), key enzymes catalyzing important steps in the phenylpropanoid and subsequent lignin biosynthetic pathways, respectively, were de-nitrosylated upon ozone stress. Measuring the in vivo and in vitro phenylalanine ammonia-lyase activity indicated that the increase of the phenylalanine ammonia-lyase activity in response to acute ozone is partly regulated by de-nitrosylation, which might favor a higher metabolic flux through the phenylpropanoid pathway within minutes after ozone exposure. PMID:25192423

  1. Gradual Soil Water Depletion Results in Reversible Changes of Gene Expression, Protein Profiles, Ecophysiology, and Growth Performance in Populus euphratica, a Poplar Growing in Arid Regions1[W][OA

    PubMed Central

    Bogeat-Triboulot, Marie-Béatrice; Brosché, Mikael; Renaut, Jenny; Jouve, Laurent; Le Thiec, Didier; Fayyaz, Payam; Vinocur, Basia; Witters, Erwin; Laukens, Kris; Teichmann, Thomas; Altman, Arie; Hausman, Jean-François; Polle, Andrea; Kangasjärvi, Jaakko; Dreyer, Erwin

    2007-01-01

    The responses of Populus euphratica Oliv. plants to soil water deficit were assessed by analyzing gene expression, protein profiles, and several plant performance criteria to understand the acclimation of plants to soil water deficit. Young, vegetatively propagated plants originating from an arid, saline field site were submitted to a gradually increasing water deficit for 4 weeks in a greenhouse and were allowed to recover for 10 d after full reirrigation. Time-dependent changes and intensity of the perturbations induced in shoot and root growth, xylem anatomy, gas exchange, and water status were recorded. The expression profiles of approximately 6,340 genes and of proteins and metabolites (pigments, soluble carbohydrates, and oxidative compounds) were also recorded in mature leaves and in roots (gene expression only) at four stress levels and after recovery. Drought successively induced shoot growth cessation, stomatal closure, moderate increases in oxidative stress-related compounds, loss of CO2 assimilation, and root growth reduction. These effects were almost fully reversible, indicating that acclimation was dominant over injury. The physiological responses were paralleled by fully reversible transcriptional changes, including only 1.5% of the genes on the array. Protein profiles displayed greater changes than transcript levels. Among the identified proteins for which expressed sequence tags were present on the array, no correlation was found between transcript and protein abundance. Acclimation to water deficit involves the regulation of different networks of genes in roots and shoots. Such diverse requirements for protecting and maintaining the function of different plant organs may render plant engineering or breeding toward improved drought tolerance more complex than previously anticipated. PMID:17158588

  2. Sulphur flux through the sulphate assimilation pathway is differently controlled by adenosine 5'-phosphosulphate reductase under stress and in transgenic poplar plants overexpressing gamma-ECS, SO, or APR.

    PubMed

    Scheerer, Ursula; Haensch, Robert; Mendel, Ralf R; Kopriva, Stanislav; Rennenberg, Heinz; Herschbach, Cornelia

    2010-01-01

    Sulphate assimilation provides reduced sulphur for the synthesis of cysteine, methionine, and numerous other essential metabolites and secondary compounds. The key step in the pathway is the reduction of activated sulphate, adenosine 5'-phosphosulphate (APS), to sulphite catalysed by APS reductase (APR). In the present study, [(35)S]sulphur flux from external sulphate into glutathione (GSH) and proteins was analysed to check whether APR controls the flux through the sulphate assimilation pathway in poplar roots under some stress conditions and in transgenic poplars. (i) O-Acetylserine (OAS) induced APR activity and the sulphur flux into GSH. (ii) The herbicide Acetochlor induced APR activity and results in a decline of GSH. Thereby the sulphur flux into GSH or protein remained unaffected. (iii) Cd treatment increased APR activity without any changes in sulphur flux but lowered sulphate uptake. Several transgenic poplar plants that were manipulated in sulphur metabolism were also analysed. (i) Transgenic poplar plants that overexpressed the gamma-glutamylcysteine synthetase (gamma-ECS) gene, the enzyme catalysing the key step in GSH formation, showed an increase in sulphur flux into GSH and sulphate uptake when gamma-ECS was targeted to the cytosol, while no changes in sulphur flux were observed when gamma-ECS was targeted to plastids. (ii) No effect on sulphur flux was observed when the sulphite oxidase (SO) gene from Arabidopsis thaliana, which catalyses the back reaction of APR, that is the reaction from sulphite to sulphate, was overexpressed. (iii) When Lemna minor APR was overexpressed in poplar, APR activity increased as expected, but no changes in sulphur flux were observed. For all of these experiments the flux control coefficient for APR was calculated. APR as a controlling step in sulphate assimilation seems obvious under OAS treatment, in gamma-ECS and SO overexpressing poplars. A possible loss of control under certain conditions, that is Cd treatment

  3. Effects of young poplar plantations on understory plant diversity in the Dongting Lake wetlands, China

    PubMed Central

    Li, Youzhi; Chen, Xinsheng; Xie, Yonghong; Li, Xu; Li, Feng; Hou, Zhiyong

    2014-01-01

    This study evaluated the effects of young poplar plantations on understory plant diversity in the Dongting Lake wetlands, China. Poplar plantations resulted in a higher species number and Shannon's diversity. Species compositions were different between areas with poplar and reed populations: a lower ratio of hygrophytes but a higher ratio of mesophytes, and a higher ratio of heliophytes but a lower ratio of neutrophilous or shade plants in poplar areas compared to reed areas. Poplar plantations supported a higher ratio of ligneous plants in the entire Dongting Lake area, but there was no difference in the monitored plots. Unlike reedy areas, poplar plantations had higher light availability but lower soil water content during the growing seasons. These data suggest that young poplar plantations generally increased species richness and plant diversity, but significantly changed species composition due to the reduced soil water and increased light availability. PMID:25208975

  4. Transgenic poplar expressing Arabidopsis YUCCA6 exhibits auxin-overproduction phenotypes and increased tolerance to abiotic stress.

    PubMed

    Ke, Qingbo; Wang, Zhi; Ji, Chang Yoon; Jeong, Jae Cheol; Lee, Haeng-Soon; Li, Hongbing; Xu, Bingcheng; Deng, Xiping; Kwak, Sang-Soo

    2015-09-01

    YUCCA6, a member of the YUCCA family of flavin monooxygenase-like proteins, is involved in the tryptophan-dependent IAA biosynthesis pathway and responses to environmental cues in Arabidopsis. However, little is known about the role of the YUCCA pathway in auxin biosynthesis in poplar. Here, we generated transgenic poplar (Populus alba × P. glandulosa) expressing the Arabidopsis YUCCA6 gene under the control of the oxidative stress-inducible SWPA2 promoter (referred to as SY plants). Three SY lines (SY7, SY12 and SY20) were selected based on the levels of AtYUCCA6 transcript. SY plants displayed auxin-overproduction morphological phenotypes, such as rapid shoot growth and retarded main root development with increased root hair formation. In addition, SY plants had higher levels of free IAA and early auxin-response gene transcripts. SY plants exhibited tolerance to drought stress, which was associated with reduced levels of reactive oxygen species. Furthermore, SY plants showed delayed hormone- and dark-induced senescence in detached leaves due to higher photosystem II efficiency and less membrane permeability. These results suggest that the conserved IAA biosynthesis pathway mediated by YUCCA family members exists in poplar.

  5. Nucleotide diversity and linkage disequilibrium in balsam poplar (Populus balsamifera).

    PubMed

    Olson, Matthew S; Robertson, Amanda L; Takebayashi, Naoki; Silim, Salim; Schroeder, William R; Tiffin, Peter

    2010-04-01

    *Current perceptions that poplars have high levels of nucleotide variation, large effective population sizes, and rapid decay of linkage disequilibrium are based primarily on studies from one poplar species, Populus tremula. *We analysed 590 gene fragments (average length 565 bp) from each of 15 individuals from different populations from throughout the range of Populus balsamifera. *Nucleotide diversity (theta(total) = 0.0028, pi = 0.0027) was low compared with other trees and model agricultural systems. Patterns of nucleotide diversity and site frequency spectra were consistent with purifying selection on replacement and intron sites. When averaged across all loci we found no evidence for decay of linkage disequilibrium across 750 bp, consistent with the low estimates of the scaled recombination parameter, rho = 0.0092. *Compared with P. tremula, a well studied congener with a similar distribution, P. balsamifera has low diversity and low effective recombination, both of which indicate a lower effective population size in P. balsamifera. Patterns of diversity and linkage indicate that there is considerable variation in population genomic patterns among poplar species and unlike P. tremula, association mapping techniques in balsam poplar should consider sampling single nucleotide polymorphisms (SNPs) at well-spaced intervals.

  6. Wood reinforcement of poplar by rice NAC transcription factor.

    PubMed

    Sakamoto, Shingo; Takata, Naoki; Oshima, Yoshimi; Yoshida, Kouki; Taniguchi, Toru; Mitsuda, Nobutaka

    2016-01-27

    Lignocellulose, composed of cellulose, hemicellulose, and lignin, in the secondary cell wall constitutes wood and is the most abundant form of biomass on Earth. Enhancement of wood accumulation may be an effective strategy to increase biomass as well as wood strength, but currently only limited research has been undertaken. Here, we demonstrated that OsSWN1, the orthologue of the rice NAC Secondary-wall Thickening factor (NST) transcription factor, effectively enhanced secondary cell wall formation in the Arabidopsis inflorescence stem and poplar (Populus tremula×Populus tremuloides) stem when expressed by the Arabidopsis NST3 promoter. Interestingly, in transgenic Arabidopsis and poplar, ectopic secondary cell wall deposition in the pith area was observed in addition to densification of the secondary cell wall in fiber cells. The cell wall content or density of the stem increased on average by up to 38% and 39% in Arabidopsis and poplar, respectively, without causing growth inhibition. As a result, physical strength of the stem increased by up to 57% in poplar. Collectively, these data suggest that the reinforcement of wood by NST3pro:OsSWN1 is a promising strategy to enhance wood-biomass production in dicotyledonous plant species.

  7. Wood reinforcement of poplar by rice NAC transcription factor

    PubMed Central

    Sakamoto, Shingo; Takata, Naoki; Oshima, Yoshimi; Yoshida, Kouki; Taniguchi, Toru; Mitsuda, Nobutaka

    2016-01-01

    Lignocellulose, composed of cellulose, hemicellulose, and lignin, in the secondary cell wall constitutes wood and is the most abundant form of biomass on Earth. Enhancement of wood accumulation may be an effective strategy to increase biomass as well as wood strength, but currently only limited research has been undertaken. Here, we demonstrated that OsSWN1, the orthologue of the rice NAC Secondary-wall Thickening factor (NST) transcription factor, effectively enhanced secondary cell wall formation in the Arabidopsis inflorescence stem and poplar (Populus tremula×Populus tremuloides) stem when expressed by the Arabidopsis NST3 promoter. Interestingly, in transgenic Arabidopsis and poplar, ectopic secondary cell wall deposition in the pith area was observed in addition to densification of the secondary cell wall in fiber cells. The cell wall content or density of the stem increased on average by up to 38% and 39% in Arabidopsis and poplar, respectively, without causing growth inhibition. As a result, physical strength of the stem increased by up to 57% in poplar. Collectively, these data suggest that the reinforcement of wood by NST3pro:OsSWN1 is a promising strategy to enhance wood-biomass production in dicotyledonous plant species. PMID:26812961

  8. Utilization of proteomics in experimental field conditions--A case study of poplars growing on grassland affected by long-term starch wastewater irrigation.

    PubMed

    Szuba, Agnieszka; Lorenc-Plucińska, Gabriela

    2015-08-03

    The presented study verified the possibility of using proteomics as a tool for investigating poplars growing on obviously separate plots. The examination covered poplars planted on grassland irrigated for 40 years with potato industry wastewater and in a plot appropriate for poplar planting, spaced at a distance of 67 km from each other (hereinafter referred to as forest). The work aimed to compare the obtained proteomic results with data on biometric and biochemical parameters and mineral composition as well as to assess, at a molecular level, the usefulness of grasslands for planting. Proteome analysis showed that most of the stress-related proteins detected were less abundant on the irrigated grassland, confirming the viability of its revegetation with poplars. Proteomic data corresponded well with the other results, highlighting the probable reason for the proteome changes; i.e. deficiency of phosphate ions detected in the forest area. Moreover, proteome analysis revealed biotic stress symptoms in plants growing on the grassland, which were also well explained by other data but would not have been detected without performing the proteomic analysis. Therefore, environmental plant proteomics is a useful and valuable tool during field studies, even when samples are taken from plots some distance apart.

  9. Isoprene biosynthesis in hybrid poplar impacts ozone tolerance

    NASA Astrophysics Data System (ADS)

    Behnke, K.; Kleist, E.; Uerlings, R.; Wildt, J.; Rennenberg, H.; Schnitzler, J. P.

    2009-04-01

    Isoprene is the most abundant volatile compound emitted by vegetation. It influences air chemistry and is thought to take part in plant defense reactions against abiotic stress such as high temperature or ozone. However, whether or not isoprene emission interacts with ozone tolerance of plants is still in discussion. We exploited transgenic non-isoprene emitting Grey poplar (Populus x canescens) in a biochemical and physiological model study to investigate the effect of acute ozone stress on the elicitation of defense-related emissions of plant volatiles, photosynthesis and the antioxidative system. We recorded that non-isoprene emitting poplars are more resistant to ozone as indicated by less damaged leaf area and higher assimilation rates compared to ozone-exposed wild type plants. The integral of green leaf volatile (GLV) emissions was different between the two poplar phenotypes and a reliable early marker for subsequent leaf damage. For other stress-induced volatiles like mono-, homo-, and sesquiterpenes, and methyl salicylate similar time profiles, pattern and emission intensities were observed in both transgenic and wild type plants. However, un-stressed non-isoprene emitting poplars are characterized by elevated levels of ascorbate and α-tocopherol as well as a more effective de-epoxidation ratio of xanthophylls than in wild type plants. Since ozone quenching properties of ascorbate are much higher than those of isoprene and furthermore α-tocopherol also is an essential antioxidant, non-isoprene emitting poplars might benefit from changes within the antioxidative system by providing them with enhanced ozone tolerance.

  10. Isoprene emission-free poplars--a chance to reduce the impact from poplar plantations on the atmosphere.

    PubMed

    Behnke, Katja; Grote, Rüdiger; Brüggemann, Nicolas; Zimmer, Ina; Zhou, Guanwu; Elobeid, Mudawi; Janz, Dennis; Polle, Andrea; Schnitzler, Jörg-Peter

    2012-04-01

    • Depending on the atmospheric composition, isoprene emissions from plants can have a severe impact on air quality and regional climate. For the plant itself, isoprene can enhance stress tolerance and also interfere with the attraction of herbivores and parasitoids. • Here, we tested the growth performance and fitness of Populus × canescens in which isoprene emission had been knocked down by RNA interference technology (PcISPS-RNAi plants) for two growing seasons under outdoor conditions. • Neither the growth nor biomass yield of the PcISPS-RNAi poplars was impaired, and they were even temporarily enhanced compared with control poplars. Modelling of the annual carbon balances revealed a reduced carbon loss of 2.2% of the total gross primary production by the absence of isoprene emission, and a 6.9% enhanced net growth of PcISPS-RNAi poplars. However, the knock down in isoprene emission resulted in reduced susceptibility to fungal infection, whereas the attractiveness for herbivores was enhanced. • The present study promises potential for the use of non- or low-isoprene-emitting poplars for more sustainable and environmentally friendly biomass production, as reducing isoprene emission will presumably have positive effects on regional climate and air quality.

  11. Prioritization of copper for the use in photosynthetic electron transport in developing leaves of hybrid poplar

    PubMed Central

    Shahbaz, Muhammad; Ravet, Karl; Peers, Graham; Pilon, Marinus

    2015-01-01

    Plastocyanin (PC) is an essential and abundant copper (Cu) protein required for photosynthesis in higher plants. Severe copper deprivation has the potential to cause a defect in photosynthetic electron transport due to a lack in PC. The Cu-microRNAs, which are up-regulated under Cu deficiency, down-regulate the expression of target Cu proteins other than PC, cytochrome-c oxidase and the ethylene receptors. It has been proposed that this mechanism saves Cu for PC maturation. We aimed to test how hybrid poplar, a species that has capacity to rapidly expand its photosynthetically active tissue, responds to variations in Cu availability over time. Measurement of chlorophyll fluorescence after Cu depletion revealed a drastic effect on photosynthesis in hybrid poplar. The decrease in photosynthetic capacity was correlated with a reduction in PC protein levels. Compared to older leaves, PC decreased more strongly in developing leaves, which also lost more photosynthetic electron transport capacity. The effect of Cu depletion on older and more developed leaves was minor and these leaves maintained much of their photosynthetic capacity. Interestingly, upon resupply of Cu to the medium a very rapid recovery of Cu levels was seen in the younger leaves with a concomitant rise in the expression and activity of PC. In contrast, the expression of those Cu proteins, which are targets of microRNAs was under the same circumstances delayed. At the same time, Cu resupply had only minor effects on the older leaves. The data suggest a model where rapid recovery of photosynthetic capacity in younger leaves is made possible by a preferred allocation of Cu to PC in younger leaves, which is supported by Cu-microRNA expression. PMID:26089828

  12. Genome Enabled Discovery of Carbon Sequestration Genes in Poplar

    SciTech Connect

    Filichkin, Sergei; Etherington, Elizabeth; Ma, Caiping; Strauss, Steve

    2007-02-22

    The goals of the S.H. Strauss laboratory portion of 'Genome-enabled discovery of carbon sequestration genes in poplar' are (1) to explore the functions of candidate genes using Populus transformation by inserting genes provided by Oakridge National Laboratory (ORNL) and the University of Florida (UF) into poplar; (2) to expand the poplar transformation toolkit by developing transformation methods for important genotypes; and (3) to allow induced expression, and efficient gene suppression, in roots and other tissues. As part of the transformation improvement effort, OSU developed transformation protocols for Populus trichocarpa 'Nisqually-1' clone and an early flowering P. alba clone, 6K10. Complete descriptions of the transformation systems were published (Ma et. al. 2004, Meilan et. al 2004). Twenty-one 'Nisqually-1' and 622 6K10 transgenic plants were generated. To identify root predominant promoters, a set of three promoters were tested for their tissue-specific expression patterns in poplar and in Arabidopsis as a model system. A novel gene, ET304, was identified by analyzing a collection of poplar enhancer trap lines generated at OSU (Filichkin et. al 2006a, 2006b). Other promoters include the pGgMT1 root-predominant promoter from Casuarina glauca and the pAtPIN2 promoter from Arabidopsis root specific PIN2 gene. OSU tested two induction systems, alcohol- and estrogen-inducible, in multiple poplar transgenics. Ethanol proved to be the more efficient when tested in tissue culture and greenhouse conditions. Two estrogen-inducible systems were evaluated in transgenic Populus, neither of which functioned reliably in tissue culture conditions. GATEWAY-compatible plant binary vectors were designed to compare the silencing efficiency of homologous (direct) RNAi vs. heterologous (transitive) RNAi inverted repeats. A set of genes was targeted for post transcriptional silencing in the model Arabidopsis system; these include the floral meristem identity gene (APETALA1 or

  13. An Empirical Assessment of Transgene Flow from a Bt Transgenic Poplar Plantation.

    PubMed

    Hu, Jianjun; Zhang, Jin; Chen, Xingling; Lv, Jinhui; Jia, Huixia; Zhao, Shutang; Lu, Mengzhu

    2017-01-01

    To assess the possible impact of transgenic poplar plantations on the ecosystem, we analyzed the frequency and distance of gene flow from a mature male transgenic Populus nigra plantation carrying the Bacillus thuringiensis toxin gene (Bt poplar) and the survival of Bt poplar seeds. The resultant Bt poplar seeds occurred at a frequency of ~0.15% at 0 m to ~0.02% at 500 m from the Bt poplar plantation. The germination of Bt poplar seeds diminished within three weeks in the field (germination rate from 68% to 0%) compared to 48% after three weeks of storage at 4°C. The survival rate of seedlings in the field was 0% without any treatment but increased to 1.7% under the addition of four treatments (cleaning and trimming, watering, weeding, and covering with plastic film to maintain moisture) after being seeded in the field for eight weeks. The results of this study indicate that gene flow originating from the Bt poplar plantation occurred at an extremely low level through pollen or seeds under natural conditions. This study provides first-hand field data on the extent of transgene flow in poplar plantations and offers guidance for the risk assessment of transgenic poplar plantations.

  14. An Empirical Assessment of Transgene Flow from a Bt Transgenic Poplar Plantation

    PubMed Central

    Chen, Xingling; Lv, Jinhui; Jia, Huixia; Zhao, Shutang; Lu, Mengzhu

    2017-01-01

    To assess the possible impact of transgenic poplar plantations on the ecosystem, we analyzed the frequency and distance of gene flow from a mature male transgenic Populus nigra plantation carrying the Bacillus thuringiensis toxin gene (Bt poplar) and the survival of Bt poplar seeds. The resultant Bt poplar seeds occurred at a frequency of ~0.15% at 0 m to ~0.02% at 500 m from the Bt poplar plantation. The germination of Bt poplar seeds diminished within three weeks in the field (germination rate from 68% to 0%) compared to 48% after three weeks of storage at 4°C. The survival rate of seedlings in the field was 0% without any treatment but increased to 1.7% under the addition of four treatments (cleaning and trimming, watering, weeding, and covering with plastic film to maintain moisture) after being seeded in the field for eight weeks. The results of this study indicate that gene flow originating from the Bt poplar plantation occurred at an extremely low level through pollen or seeds under natural conditions. This study provides first-hand field data on the extent of transgene flow in poplar plantations and offers guidance for the risk assessment of transgenic poplar plantations. PMID:28085955

  15. Nitrogen ion utilization by tulip poplar (Liriodendron tulipifera L. ) seedlings

    SciTech Connect

    Mann, L.K.

    1982-01-01

    Growth responses of one-year-old tulip poplar seedlings were determined for different nitrogen sources (HN/sub 4/NO/sub 3/, NH+/sub 4/, NO-/sub 3/, no nitrogen) at 336 ppm N in nutrient culture. At the end of three months, there were no significant differences in growth observed among treatments in terms of stem elongation, leaf area, and leaf size. After four months, however, seedlings of the NH/sub 4/NO/sub 3/ treatment exhibited significantly (P<0.05) greater growth (final weight gain and stem elongation) than all other nitrogen sorces. Growth was slightly less for the NO-/sub 3/ treatment plants, but compared with NH+/sub 4/ and no nitrogen treatment, both NH/sub 4/NO/sub 3/ and NO-/sub 3/ treatments exhibited significantly greater growth responses. NO-/sub 3/ is recommended as the sole nitrogen source, especially for small seedlings of tulip poplar.

  16. [Phosphorus transfer between mixed poplar and black locust seedlings].

    PubMed

    He, Wei; Jia, Liming; Hao, Baogang; Wen, Xuejun; Zhai, Mingpu

    2003-04-01

    In this paper, the 32P radio-tracer technique was applied to study the ways of phosphorus transfer between poplar (Populus euramericana cv. 'I-214') and black locust (Robinia pseudoacacia). A five compartment root box (18 cm x 18 cm x 26 cm) was used for testing the existence of the hyphal links between the roots of two tree species when inoculated with vesicular-arbuscular (VA) mycorrhizal fungus (Glomus mosseae). Populus I-214 (donor) and Robinia pseudoacacia (receiver) were grown in two terminal compartments, separated by a 2 cm root-free soil layer. The root compartments were lined with bags of nylon mesh (38 microns) that allowed the passage of hyphae but not roots. The top soil of a mixed stand of poplar and black locust, autoclaved at 121 degrees C for one hour, was used for growing seedlings for testing. In 5 compartment root box, mycorrhizal root colonization of poplar was 34%, in which VA mycorrhizal fungus was inoculated, whereas 26% mycorrhizal root colonization was observed in black locust, the other terminal compartment, 20 weeks after planting. No root colonization was observed in non-inoculated plant pairs. This indicated that the mycorrhizal root colonization of black locust was caused by hyphal spreading from the poplar. Test of tracer isotope of 32P showed that the radioactivity of the treatment significantly higher than that of the control (P < 0.05), 14 days from the tracer applied, to 27 days after, when VA mycorrhizal fungus was inoculated in poplar root. Furthermore, mycorrhizal interconnections between the roots of poplar and black locust seedlings was observed in situ by binocular in root box. All these experiments showed that the hyphal links was formed between the roots of two species of trees inoculated by VA mycorrhizal fungus. Four treatments were designed according to if there were two nets (mesh 38 microns), 2 cm apart, between the poplar and black locust, and if the soil in root box was pasteurized. Most significant differences of

  17. Poplar PdC3H17 and PdC3H18 are direct targets of PdMYB3 and PdMYB21, and positively regulate secondary wall formation in Arabidopsis and poplar.

    PubMed

    Chai, Guohua; Qi, Guang; Cao, Yingping; Wang, Zengguang; Yu, Li; Tang, Xianfeng; Yu, Yanchong; Wang, Dian; Kong, Yingzhen; Zhou, Gongke

    2014-07-01

    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 cytoplasmic foci. Transcriptional activation assays showed that PdMYB2/3/20/21 individually activated the PdC3H17 and PdC3H18 promoters, but PdMYB3/21 were most significant. Electrophoretic mobility shift assays revealed that PdMYB3/21 bound directly to the PdC3H17/18 promoters. Overexpression of PdC3H17/18 in poplar increased secondary xylem width and secondary wall thickening in stems, whereas dominant repressors of them had the opposite effects on these traits. Similar alteration in secondary wall thickening was observed in their transgenic Arabidopsis plants. qRT-PCR results showed that PdC3H17/18 regulated the expression of cellulose, xylan and lignin biosynthetic genes, and several wood-associated MYB genes. These results demonstrate that PdC3H17 and PdC3H18 are the targets of PdMYB3 and PdMYB21 and are an additional two components in the regulatory network of secondary xylem formation in poplar.

  18. The poplar Phi class glutathione transferase: expression, activity and structure of GSTF1

    PubMed Central

    Pégeot, Henri; Koh, Cha San; Petre, Benjamin; Mathiot, Sandrine; Duplessis, Sébastien; Hecker, Arnaud; Didierjean, Claude; Rouhier, Nicolas

    2014-01-01

    Glutathione transferases (GSTs) constitute a superfamily of enzymes with essential roles in cellular detoxification and secondary metabolism in plants as in other organisms. Several plant GSTs, including those of the Phi class (GSTFs), require a conserved catalytic serine residue to perform glutathione (GSH)-conjugation reactions. Genomic analyses revealed that terrestrial plants have around ten GSTFs, eight in the Populus trichocarpa genome, but their physiological functions and substrates are mostly unknown. Transcript expression analyses showed a predominant expression of all genes both in reproductive (female flowers, fruits, floral buds) and vegetative organs (leaves, petioles). Here, we show that the recombinant poplar GSTF1 (PttGSTF1) possesses peroxidase activity toward cumene hydroperoxide and GSH-conjugation activity toward model substrates such as 2,4-dinitrochlorobenzene, benzyl and phenetyl isothiocyanate, 4-nitrophenyl butyrate and 4-hydroxy-2-nonenal but interestingly not on previously identified GSTF-class substrates. In accordance with analytical gel filtration data, crystal structure of PttGSTF1 showed a canonical dimeric organization with bound GSH or 2-(N-morpholino)ethanesulfonic acid molecules. The structure of these protein-substrate complexes allowed delineating the residues contributing to both the G and H sites that form the active site cavity. In sum, the presence of GSTF1 transcripts and proteins in most poplar organs especially those rich in secondary metabolites such as flowers and fruits, together with its GSH-conjugation activity and its documented stress-responsive expression suggest that its function is associated with the catalytic transformation of metabolites and/or peroxide removal rather than with ligandin properties as previously reported for other GSTFs. PMID:25566286

  19. Poplar for the phytomanagement of boron contaminated sites.

    PubMed

    Robinson, B H; Green, S R; Chancerel, B; Mills, T M; Clothier, B E

    2007-11-01

    Boron (B) is a widespread environmental contaminant that is mobile relative to other trace elements. We investigated the potential of hybrid poplar (Populus sp.) for B phytomanagement using a lysimeter experiment and a field trial on B-contaminated wood-waste. In both studies, poplars enhanced evapotranspiration from the wood-waste, reduced B leaching, and accumulated B in the aerial portions of the tree. When grown in a substrate containing 30 mg/kg B, poplar leaves had an average B concentration of 845 mg/kg, while the stems contained 21 mg/kg B. Leaf B concentrations increased linearly with leaf age. A decomposition experiment revealed that abscised leaves released 14% of their B during the winter months. Fertiliser application enhanced tree growth without decreasing the leaf B concentrations. Harvesting alternate rows of trees on a contaminated site would reduce leaching from the site while removing B. Harvested plant material may provide bioenergy, stock fodder, or an amendment for B-deficient soils.

  20. Modeling sustainable reuse of nitrogen-laden wastewater by poplar.

    PubMed

    Wang, Yusong; Licht, Louis; Just, Craig

    2016-01-01

    Numerical modeling was used to simulate the leaching of nitrogen (N) to groundwater as a consequence of irrigating food processing wastewater onto grass and poplar under various management scenarios. Under current management practices for a large food processor, a simulated annual N loading of 540 kg ha(-1) yielded 93 kg ha(-1) of N leaching for grass and no N leaching for poplar during the growing season. Increasing the annual growing season N loading to approximately 1,550 kg ha(-1) for poplar only, using "weekly", "daily" and "calculated" irrigation scenarios, yielded N leaching of 17 kg ha(-1), 6 kg ha(-1), and 4 kg ha(-1), respectively. Constraining the simulated irrigation schedule by the current onsite wastewater storage capacity of approximately 757 megaliters (Ml) yielded N leaching of 146 kg ha(-1) yr(-1) while storage capacity scenarios of 3,024 and 4,536 Ml yielded N leaching of 65 and 13 kg ha(-1) yr(-1), respectively, for a loading of 1,550 kg ha(-1) yr(-1). Further constraining the model by the current wastewater storage volume and the available land area (approximately 1,000 hectares) required a "diverse" irrigation schedule that was predicted to leach a weighted average of 13 kg-N ha(-1) yr(-1) when dosed with 1,063 kg-N ha(-1) yr(-1).

  1. Heat transfer mechanisms in poplar wood undergoing torrefaction

    NASA Astrophysics Data System (ADS)

    Sule, Idris O.; Mahmud, Shohel; Dutta, Animesh; Tasnim, Syeda Humaira

    2016-03-01

    Torrefaction, a thermal treatment process of biomass, has been proved to improve biomass combustible properties. Torrefaction is defined as a thermochemical process in reduced oxygen condition and at temperature range from 200 to 300 °C for shorter residence time whereby energy yield is maximized, can be a bridging technology that can lead the conventional system (e.g. coal-fired plants) towards a sustainable energy system. In efforts to develop a commercial operable torrefaction reactor, the present study examines the minimum input condition at which biomass is torrefied and explores the heat transfer mechanisms during torrefaction in poplar wood samples. The heat transfer through the wood sample is numerically modeled and analyzed. Each poplar wood is torrefied at temperature of 250, 270, and 300 °C. The experimental study shows that the 270 °C-treatment can be deduced as the optimal input condition for torrefaction of poplar wood. A good understanding of heat transfer mechanisms can facilitate the upscaling and downscaling of torrefaction process equipment to fit the feedstock input criteria and can help to develop treatment input specifications that can maximize process efficiency.

  2. Carbon balance in leaves of young poplar trees.

    PubMed

    Mayrhofer, S; Heizmann, U; Magel, E; Eiblmeier, M; Müller, A; Rennenberg, H; Hampp, R; Schnitzler, J-P; Kreuzwieser, J

    2004-11-01

    In the present study, important components of carbon metabolism of mature leaves of young poplar trees (Populus x canescens) were determined. Carbohydrate concentrations in leaves and xylem sap were quantified at five different times during the day and compared with photosynthetic gas exchange measurements (net assimilation, transpiration and rates of isoprene emission). Continuously measured xylem sap flow rates, with a time resolution of 15 min, were used to calculate diurnal balances of carbon metabolism of whole mature poplar leaves on different days. Loss of photosynthetically fixed carbon by isoprene emission and dark respiration amounted to 1% and 20%. The most abundant soluble carbohydrates in leaves and xylem sap were glucose, fructose and sucrose, with amounts of approx. 2 to 12 mmol m(-2) leaf area in leaves and about 0.2 to 15 mM in xylem sap. Clear diurnal patterns of carbohydrate concentration in xylem sap and leaves, however, were not observed. Calculations of the carbon transport rates in the xylem to the leaves were based on carbohydrate concentrations in xylem sap and xylem sap flow rates. This carbon delivery amounted to about 3 micromol C m(-2) s(-1) during the day and approx. 1 micromol C m(-2) s(-1) at night. The data demonstrated that between 9 and 28 % of total carbon delivered to poplar leaves during 24 h resulted from xylem transport and, hence, provide a strong indication for a significant rate of carbon cycling within young trees.

  3. Effective alkaline metal-catalyzed oxidative delignification of hybrid poplar

    SciTech Connect

    Bhalla, Aditya; Bansal, Namita; Stoklosa, Ryan J.; Fountain, Mackenzie; Ralph, John; Hodge, David B.; Hegg, Eric L.

    2016-02-09

    Background: Strategies to improve copper-catalyzed alkaline hydrogen peroxide (Cu-AHP) pretreatment of hybrid poplar were investigated. These improvements included a combination of increasing hydrolysis yields, while simultaneously decreasing process inputs through (i) more efficient utilization of H2O2 and (ii) the addition of an alkaline extraction step prior to the metal-catalyzed AHP pretreatment. We hypothesized that utilizing this improved process could substantially lower the chemical inputs needed during pretreatment. Results: Hybrid poplar was pretreated utilizing a modified process in which an alkaline extraction step was incorporated prior to the Cu-AHP treatment step and H2O2 was added batch-wise over the course of 10 h. Our results revealed that the alkaline pre-extraction step improved both lignin and xylan solubilization, which ultimately led to improved glucose (86 %) and xylose (95 %) yields following enzymatic hydrolysis. An increase in the lignin solubilization was also observed with fed-batch H2O2 addition relative to batch-only addition, which again resulted in increased glucose and xylose yields (77 and 93 % versus 63 and 74 %, respectively). Importantly, combining these strategies led to significantly improved sugar yields (96 % glucose and 94 % xylose) following enzymatic hydrolysis. In addition, we found that we could substantially lower the chemical inputs (enzyme, H2O2, and catalyst), while still maintaining high product yields utilizing the improved Cu-AHP process. This pretreatment also provided a relatively pure lignin stream consisting of ≥90 % Klason lignin and only 3 % xylan and 2 % ash following precipitation. Two-dimensional heteronuclear single-quantum coherence (2D HSQC) NMR and size-exclusion chromatography demonstrated that the solubilized lignin was high molecular weight (Mw ≈ 22,000 Da) and only slightly oxidized relative to lignin

  4. Effective alkaline metal-catalyzed oxidative delignification of hybrid poplar

    DOE PAGES

    Bhalla, Aditya; Bansal, Namita; Stoklosa, Ryan J.; ...

    2016-02-09

    Background: Strategies to improve copper-catalyzed alkaline hydrogen peroxide (Cu-AHP) pretreatment of hybrid poplar were investigated. These improvements included a combination of increasing hydrolysis yields, while simultaneously decreasing process inputs through (i) more efficient utilization of H2O2 and (ii) the addition of an alkaline extraction step prior to the metal-catalyzed AHP pretreatment. We hypothesized that utilizing this improved process could substantially lower the chemical inputs needed during pretreatment. Results: Hybrid poplar was pretreated utilizing a modified process in which an alkaline extraction step was incorporated prior to the Cu-AHP treatment step and H2O2 was added batch-wise over the course of 10more » h. Our results revealed that the alkaline pre-extraction step improved both lignin and xylan solubilization, which ultimately led to improved glucose (86 %) and xylose (95 %) yields following enzymatic hydrolysis. An increase in the lignin solubilization was also observed with fed-batch H2O2 addition relative to batch-only addition, which again resulted in increased glucose and xylose yields (77 and 93 % versus 63 and 74 %, respectively). Importantly, combining these strategies led to significantly improved sugar yields (96 % glucose and 94 % xylose) following enzymatic hydrolysis. In addition, we found that we could substantially lower the chemical inputs (enzyme, H2O2, and catalyst), while still maintaining high product yields utilizing the improved Cu-AHP process. This pretreatment also provided a relatively pure lignin stream consisting of ≥90 % Klason lignin and only 3 % xylan and 2 % ash following precipitation. Two-dimensional heteronuclear single-quantum coherence (2D HSQC) NMR and size-exclusion chromatography demonstrated that the solubilized lignin was high molecular weight (Mw ≈ 22,000 Da) and only slightly oxidized relative to lignin from untreated poplar. In conclusion: This study demonstrated that the fed

  5. Fitness dynamics within a poplar hybrid zone: I. Prezygotic and postzygotic barriers impacting a native poplar hybrid stand

    PubMed Central

    Roe, Amanda D; MacQuarrie, Chris J K; Gros-Louis, Marie-Claude; Simpson, J Dale; Lamarche, Josyanne; Beardmore, Tannis; Thompson, Stacey L; Tanguay, Philippe; Isabel, Nathalie

    2014-01-01

    Hybridization and introgression are pervasive evolutionary phenomena that provide insight into the selective forces that maintain species boundaries, permit gene flow, and control the direction of evolutionary change. Poplar trees (Populus L.) are well known for their ability to form viable hybrids and maintain their distinct species boundaries despite this interspecific gene flow. We sought to quantify the hybridization dynamics and postzygotic fitness within a hybrid stand of balsam poplar (Populus balsamifera L.), eastern cottonwood (P. deltoides Marsh.), and their natural hybrids to gain insight into the barriers maintaining this stable hybrid zone. We observed asymmetrical hybrid formation with P. deltoides acting as the seed parent, but with subsequent introgression biased toward P. balsamifera. Native hybrids expressed fitness traits intermediate to the parental species and were not universally unfit. That said, native hybrid seedlings were absent from the seedling population, which may indicate additional selective pressures controlling their recruitment. It is imperative that we understand the selective forces maintaining this native hybrid zone in order to quantify the impact of exotic poplar hybrids on this native system. PMID:24967081

  6. Functional Characterization and Subcellular Localization of Poplar (Populus trichocarpa × Populus deltoides) Cinnamate 4-Hydroxylase1

    PubMed Central

    Ro, Dae Kyun; Mah, Nancy; Ellis, Brian E.; Douglas, Carl J.

    2001-01-01

    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 × P. deltoides) young leaf cDNA library. RNA-blot analysis detected C4H transcripts in all organs tested, but the gene was most highly expressed in developing xylem. C4H expression was also strongly induced by elicitor-treatment in poplar cell cultures. To verify the catalytic activity of the putative C4H cDNA, two constructs, C4H and C4H fused to the FLAG epitope (C4H::FLAG), were expressed in yeast. Immunoblot analysis showed that C4H was present in the microsomal fraction and microsomal preparations from strains expressing both enzymes efficiently converted cinnamic acid to p-coumaric acid with high specific activities. To investigate the subcellular localization of C4H in vivo, a chimeric C4H-green fluorescent protein (GFP) gene was engineered and stably expressed in Arabidopsis. Confocal laser microscopy analysis clearly showed that in Arabidopsis the C4H::GFP chimeric enzyme was localized to the ER. When expressed in yeast, the C4H::GFP fusion enzyme was also active but displayed significantly lower specific activity than either C4H or C4H::FLAG in in vitro and in vivo enzyme assays. These data definitively show that C4H is localized to the ER in planta. PMID:11351095

  7. Down-regulation of gibberellic acid in poplar has negligible effects on host-plant suitability and insect pest response

    DOE PAGES

    Buhl, Christine; Strauss, Steven H.; Lindroth, Richard L.

    2015-01-06

    Abstract Endogenous levels and signaling of gibberellin plant hormones such as gibberellic acid (GA) have been genetically down-regulated to create semi-dwarf varieties of poplar. The potential benefits of semi-dwarf stature include reduced risk of wind damage, improved stress tolerance, and improved wood quality. Despite these benefits, modification of growth traits may have consequences for non-target traits that confer defense against insect herbivores. According to the growth-differentiation balance hypothesis, reductions in growth may shift allocation of carbon from growth to chemical resistance traits, thereby altering plant defense. To date, host-plant suitability and pest response have not been comprehensively evaluated in GAmore » down-regulated plants. We quantified chemical resistance and nitrogen (an index of protein) in GA down-regulated and wild-type poplar (Populus alba × P. tremula) genotypes. We also evaluated performance of both generalist (Lymantria dispar) and specialist (Chrysomela scripta) insect pests reared on these genotypes. Our evaluation of resistance traits in four GA down-regulated genotypes revealed increased phenolic glycosides in one modified genotype and reduced lignin in two modified genotypes relative to the non-transgenic wild type. Nitrogen levels did not vary significantly among the experimental genotypes. Generalists reared on the four GA down-regulated genotypes exhibited reduced performance on only one modified genotype relative to the wild type. Specialists, however, performed similarly across all genotypes. Results from this study indicate that although some non-target traits varied among GA down-regulated genotypes, the differences in poplar pest susceptibility were modest and highly genotype-specific.« less

  8. Down-regulation of gibberellic acid in poplar has negligible effects on host-plant suitability and insect pest response

    SciTech Connect

    Buhl, Christine; Strauss, Steven H.; Lindroth, Richard L.

    2015-01-06

    Abstract Endogenous levels and signaling of gibberellin plant hormones such as gibberellic acid (GA) have been genetically down-regulated to create semi-dwarf varieties of poplar. The potential benefits of semi-dwarf stature include reduced risk of wind damage, improved stress tolerance, and improved wood quality. Despite these benefits, modification of growth traits may have consequences for non-target traits that confer defense against insect herbivores. According to the growth-differentiation balance hypothesis, reductions in growth may shift allocation of carbon from growth to chemical resistance traits, thereby altering plant defense. To date, host-plant suitability and pest response have not been comprehensively evaluated in GA down-regulated plants. We quantified chemical resistance and nitrogen (an index of protein) in GA down-regulated and wild-type poplar (Populus alba × P. tremula) genotypes. We also evaluated performance of both generalist (Lymantria dispar) and specialist (Chrysomela scripta) insect pests reared on these genotypes. Our evaluation of resistance traits in four GA down-regulated genotypes revealed increased phenolic glycosides in one modified genotype and reduced lignin in two modified genotypes relative to the non-transgenic wild type. Nitrogen levels did not vary significantly among the experimental genotypes. Generalists reared on the four GA down-regulated genotypes exhibited reduced performance on only one modified genotype relative to the wild type. Specialists, however, performed similarly across all genotypes. Results from this study indicate that although some non-target traits varied among GA down-regulated genotypes, the differences in poplar pest susceptibility were modest and highly genotype-specific.

  9. Limited impact of elevated levels of polyphenol oxidase on tree-feeding caterpillars: assessing individual plant defenses with transgenic poplar.

    PubMed

    Barbehenn, Raymond V; Jones, Christopher P; Yip, Lynn; Tran, Lan; Constabel, C Peter

    2007-11-01

    Polyphenol oxidase (PPO) is commonly believed to function as an effective antiherbivore defense in plants. PPO is induced in plants following herbivory, and insect performance is often negatively correlated with PPO levels. However, induced defenses create numerous changes in plants, and very little work has been done to test the direct effects of PPO on insect herbivores separately from other changes. This study examined the impacts of high levels of PPO on the performance of two species of tree-feeding caterpillars (Lymantria dispar and Orgyia leucostigma) on poplar. Transgenic PPO-overexpressing poplar (Populus tremula x Populus alba) was used as a source of elevated-PPO leaves, thereby controlling for the multiple effects of induction. In addition, the impacts of treating poplar foliage with high levels of purified mushroom PPO were examined on the two caterpillar species. Contrary to expectation, in several cases increased PPO levels had no significant effect on insect consumption or growth rates. Although one of the mechanisms by which PPO is believed to impact herbivores is via increased oxidative stress, the ingestion of large amounts of PPO had little or no effect on semiquinone radical and oxidized protein levels in the gut contents of lymantriid caterpillars. PPO activity in caterpillars is likely limited by the low oxygen and high ascorbate levels commonly found in their gut contents. This study questions whether induced PPO functions as an effective post-ingestive defense against tree-feeding caterpillars, and indicates that controlled, mechanistic studies are needed in other plant-herbivore systems to test for a direct effect of PPO on insect performance.

  10. Quantitative Proteomic and Phosphoproteomic Approaches for Deciphering the Signaling Pathway for Tension Wood Formation in Poplar.

    PubMed

    Mauriat, Mélanie; Leplé, Jean-Charles; Claverol, Stéphane; Bartholomé, Jérôme; Negroni, Luc; Richet, Nicolas; Lalanne, Céline; Bonneu, Marc; Coutand, Catherine; Plomion, Christophe

    2015-08-07

    Trees adjust their growth following forced changes in orientation to re-establish a vertical position. In angiosperms, this adjustment involves the differential regulation of vascular cambial activity between the lower (opposite wood) and upper (tension wood) sides of the leaning stem. We investigated the molecular mechanisms leading to the formation of differential wood types through a quantitative proteomic and phosphoproteomic analysis on poplar subjected to a gravitropic stimulus. We identified and quantified 675 phosphopeptides, corresponding to 468 phosphoproteins, and 3 763 nonphosphorylated peptides, corresponding to 1 155 proteins, in the differentiating xylem of straight-growing trees (control) and trees subjected to a gravitational stimulus during 8 weeks. About 1% of the peptides were specific to a wood type (straight, opposite, or tension wood). Proteins quantified in more than one type of wood were more numerous: a mixed linear model showed 389 phosphopeptides and 556 proteins to differ in abundance between tension wood and opposite wood. Twenty-one percent of the phosphoproteins identified here were described in their phosphorylated form for the first time. Our analyses revealed remarkable developmental molecular plasticity, with wood type-specific phosphorylation events, and highlighted the involvement of different proteins in the biosynthesis of cell wall components during the formation of the three types of wood.

  11. Metagenome of an Anaerobic Microbial Community Decomposing Poplar Wood Chips

    SciTech Connect

    van der Lelie, D.; Taghavi, S.; McCorkle, S. M.; Li, L. L.; Malfatti, S. A.; Monteleone, D.; Donohoe, B. S.; Ding, S. Y.; Adney, W. S.; Himmel, M. E.; Tringe, S. G.

    2012-05-01

    This study describes the composition and metabolic potential of a lignocellulosic biomass degrading community that decays poplar wood chips under anaerobic conditions. We examined the community that developed on poplar biomass in a non-aerated bioreactor over the course of a year, with no microbial inoculation other than the naturally occurring organisms on the woody material. The composition of this community contrasts in important ways with biomass-degrading communities associated with higher organisms, which have evolved over millions of years into a symbiotic relationship. Both mammalian and insect hosts provide partial size reduction, chemical treatments (low or high pH environments), and complex enzymatic 'secretomes' that improve microbial access to cell wall polymers. We hypothesized that in order to efficiently degrade coarse untreated biomass, a spontaneously assembled free-living community must both employ alternative strategies, such as enzymatic lignin depolymerization, for accessing hemicellulose and cellulose and have a much broader metabolic potential than host-associated communities. This would suggest that such a community would make a valuable resource for finding new catalytic functions involved in biomass decomposition and gaining new insight into the poorly understood process of anaerobic lignin depolymerization. Therefore, in addition to determining the major players in this community, our work specifically aimed at identifying functions potentially involved in the depolymerization of cellulose, hemicelluloses, and lignin, and to assign specific roles to the prevalent community members in the collaborative process of biomass decomposition. A bacterium similar to Magnetospirillum was identified among the dominant community members, which could play a key role in the anaerobic breakdown of aromatic compounds. We suggest that these compounds are released from the lignin fraction in poplar hardwood during the decay process, which would point to

  12. Some physicochemical peculiarities of poplar plastocyanins a and b.

    PubMed

    Christova, Petya K; Donchev, Anthony A; Shosheva, Alexandra C; Getov, Vladimir I; Dimitrov, Mitko I

    2009-01-01

    The redox potentials of poplar plastocyanins a and b (PCa, PCb) were determined by spectrophotometric titrations of their reduced forms with [Fe(CN)6]3-. It was found that the two isoforms have the following millimolar extinction coefficients epsilon597 equilibrium constants Keq of one-electron exchange with [Fe(CN)6]4-/[Fe(CN)6]3-, and standard electron potentials E0: PCa: epsilon597 = (4.72 +/- 0.08) mM(-1) cm(-1), Keq = 0.133 +/- 0.009, E0' = (354 +/- 11) mV; PCb: epsilon597 = (5.23 +/- 0.16) mM(-1) cm(-1), Keq = 0.175 +/- 0.010, E0' = (363 +/- 12) mV. The pH dependence of the redox potential of PCb was studied too. It was found, that the value of E0' for PCb is constant in the pH range 6.5-9.5, but decreases in the range 4.8-6.5. On the whole, the dependence resembles that of PC from some well-known plant species, including poplar PCa. The changes of E0' in the pH-dependent region for poplar PCb, however, are smaller and are 13 mV per pH unit, whereas in the other well-known plant species the changes are about 50-60 mV per pH unit. It has been assumed that the weaker pH dependence of EO' of PCb accounts for some structural differences between PCa and PCb.

  13. Symplastic Phloem Loading in Poplar1[W][OPEN

    PubMed Central

    Zhang, Cankui; Han, Lu; Slewinski, Thomas L.; Sun, Jianlei; Zhang, Jing; Wang, Zeng-Yu; Turgeon, Robert

    2014-01-01

    Sap is driven through phloem sieve tubes by an osmotically generated pressure gradient between source and sink tissues. In many plants, source pressure results from thermodynamically active loading in which energy is used to transfer sucrose (Suc) from mesophyll cells to the phloem of leaf minor veins against a concentration gradient. However, in some species, almost all trees, correlative evidence suggests that sugar migrates passively through plasmodesmata from mesophyll cells into the sieve elements. The possibility of alternate loading mechanisms has important ramifications for the regulation of phloem transport and source-sink interactions. Here, we provide experimental evidence that, in gray poplar (Populus tremula × Populus alba), Suc enters the phloem through plasmodesmata. Transgenic plants were generated with yeast invertase in the cell walls to prevent Suc loading by this route. The constructs were driven either by the constitutive 35S promoter or the minor vein-specific galactinol synthase promoter. Transgenic plants grew at the same rate as the wild type without symptoms of loading inhibition, such as accumulation of carbohydrates or leaf chlorosis. Rates of photosynthesis were normal. In contrast, alfalfa (Medicago sativa) plants, which have limited numbers of plasmodesmata between mesophyll and phloem, displayed typical symptoms of loading inhibition when transformed with the same DNA constructs. The results are consistent with passive loading of Suc through plasmodesmata in poplar. We also noted defense-related symptoms in leaves of transgenic poplar when the plants were abruptly exposed to excessively high temperatures, adding to evidence that hexose is involved in triggering the hypersensitive response. PMID:25056922

  14. Two poplar cellulose synthase-like D genes, PdCSLD5 and PdCSLD6, are functionally conserved with Arabidopsis CSLD3.

    PubMed

    Qi, Guang; Hu, Ruibo; Yu, Li; Chai, Guohua; Cao, Yingping; Zuo, Ran; Kong, Yingzhen; Zhou, Gongke

    2013-09-15

    Root hairs are tip-growing long tubular outgrowths of specialized epidermal cells, and are important for nutrient and water uptake and interaction with the soil microflora. Here we characterized two poplar cellulose synthase-like D (CSLD) genes, PdCSLD5 and PdCSLD6, the most probable orthologs to the Arabidopsis AtCSLD3/KOJAK gene. Both PdCSLD5 and PdCSLD6 are strongly expressed in roots, including in the root hairs. Subcellular localization experiments showed that these two proteins are located not only in the polarized plasma membrane of root hair tips, but also in Golgi apparatus of the root hair and non-hair-forming cells. Overexpression of these two poplar genes in the atcsld3 mutant was able to rescue most of the defects caused by disruption of AtCSLD3, including root hair morphological changes, altered cell wall monosaccharide composition, increased non-crystalline β-1,4-glucan and decreased crystalline cellulose contents. Taken together, our results provide evidence indicating that PdCSLD5 and PdCSLD6 are functionally conserved with AtCSLD3 and support a role for PdCSLD5 and PdCSL6 specifically in crystalline cellulose production in poplar root hair tips. The results presented here also suggest that at least part of the mechanism of root hair formation is conserved between herbaceous and woody plants.

  15. Genetic structure and regulation of isoprene synthase in Poplar (Populus spp.).

    PubMed

    Vickers, Claudia E; Possell, Malcolm; Nicholas Hewitt, C; Mullineaux, Philip M

    2010-07-01

    Isoprene is a volatile 5-carbon hydrocarbon derived from the chloroplastic methylerythritol 2-C-methyl-D: -erythritol 4-phosphate isoprenoid pathway. In plants, isoprene emission is controlled by the enzyme isoprene synthase; however, there is still relatively little known about the genetics and regulation of this enzyme. Isoprene synthase gene structure was analysed in three poplar species. It was found that genes encoding stromal isoprene synthase exist as a small gene family, the members of which encode virtually identical proteins and are differentially regulated. Accumulation of isoprene synthase protein is developmentally regulated, but does not differ between sun and shade leaves and does not increase when heat stress is applied. Our data suggest that, in mature leaves, isoprene emission rates are primarily determined by substrate (dimethylallyl diphosphate, DMADP) availability. In immature leaves, where isoprene synthase levels are variable, emission levels are also influenced by the amount of isoprene synthase protein. No thylakoid isoforms could be identified in Populus alba or in Salix babylonica. Together, these data show that control of isoprene emission at the genetic level is far more complicated than previously assumed.

  16. [Carbon storage of poplar-crop ecosystem in Eastern Henan Plain].

    PubMed

    Li, Qing-Yun; Fan, Wei; Yu, Xin-Xiao; Wan, Meng

    2010-03-01

    Aimed to understand the carbon storage of poplar-crop ecosystem in Eastern Henan Plain, the poplar-crop ecosystems with different ages (5, 9, 11, and 13 years old) of poplar were selected, and each of them was further divided into four subsystems, i. e. , forest, crop, litterfall, and soil. In the poplar-crop ecosystems with 5, 9, 11, and 13 years old poplar, the carbon storage of the subsystems forest and litterfall was summed as 7.86, 42.07, 44.31, and 60.71 t x hm(-2), respectively. Subsystem crop averagely sequestrated 6. 8 t x hm(-2) of CO2 per year, and the carbon storage of subsystem soil achieved 45.55, 51.06, 55.94, and 60.49 t x hm(-2), respectively. The total carbon storage of these four poplar-crop ecosystems reached 60.81, 100.09, 106.76, and 127.34 t x hm(-2), respectively, much higher than that in mono-cultured farmland (49.36 t x hm(-2)). For the test poplar-crop ecosystems, the carbon storage of subsystems forest and soil occupied a large proportion, accounting for 87.1%-93.1% of the total carbon storage, while that of subsystems crop and litterfall occupied a relatively small proportion, being 6.9%-12.9% of the total, illustrating that agroforestry ecosystem had a high potential in carbon absorption and sequestration.

  17. Characterization of top phase oil obtained from co-pyrolysis of sewage sludge and poplar sawdust.

    PubMed

    Zuo, Wu; Jin, Baosheng; Huang, Yaji; Sun, Yu

    2014-01-01

    To research the impact of adding sawdust on top phase oil, a sewage sludge and poplar sawdust co-pyrolysis experiment was performed in a fixed bed. Gas chromatography (GC)/mass spectrometry (MS) was used to analyze the component distribution of top phase oil. Higher heating value, viscosity, water content, and pH of the top phase oil product were determined. The highest top phase oil yield (5.13 wt%) was obtained from the mixture containing 15% poplar sawdust, while the highest oil yield (16.51 wt%) was obtained from 20% poplar sawdust. Top phase oil collected from the 15% mixture also has the largest amount of aliphatics and the highest higher heating value (28.6 MJ/kg). Possible reaction pathways were proposed to explain the increase in the types of phenols present in the top phase oil as the proportion of poplar sawdust used in the mixture increased. It can be concluded that synergetic reactions occurred during co-pyrolysis of sewage sludge and poplar sawdust. The results indicate that the high ash content of the sewage sludge may be responsible for the characteristic change in the top phase oil obtained from the mixtures containing different proportions of sewage sludge and poplar sawdust. Consequently, co-pyrolysis of the mixture containing 15 % poplar sawdust can increase the yield and the higher heating value of top phase oil.

  18. Enhancement of Biogas Yield of Poplar Leaf by High-Solid Codigestion with Swine Manure.

    PubMed

    Wangliang, Li; Zhikai, Zhang; Guangwen, Xu

    2016-05-01

    The aim of this work was to examine the improvement of anaerobic biodegradability of organic fractions of poplar leaf from codigestion with swine manure (SM), thus biogas yield and energy recovery. When poplar leaf was used as a sole substrate, the cumulative biogas yield was low, about 163 mL (g volatile solid (VS))(-1) after 45 days of digestion with a substrate/inoculum ratio of 2.5 and a total solid (TS) of 22 %. Under the same condition, the cumulative biogas yield of poplar leaf reached 321 mL (g VS)(-1) when SM/poplar leaf ratio was 2:5 (based on VS). The SM/poplar leaf ratio can determine C/N ratio of the cosubstrate and thus has significant influence on biogas yield. When the SM/poplar leaf ratio was 2:5, C/N ratio was calculated to be 27.02, and the biogas yield in 45 days of digestion was the highest. The semi-continuous digestion of poplar leaf was carried out with the organic loading rate of 1.25 and 1.88 g VS day(-1). The average daily biogas yield was 230.2 mL (g VS)(-1) and 208.4 mL (g VS)(-1). The composition analysis revealed that cellulose and hemicellulose contributed to the biogas production.

  19. Major Chromosomal Rearrangements Distinguish Willow and Poplar After the Ancestral “Salicoid” Genome Duplication

    PubMed Central

    Hou, Jing; Ye, Ning; Dong, Zhongyuan; Lu, Mengzhu; Li, Laigeng; Yin, Tongming

    2016-01-01

    Populus (poplar) and Salix (willow) are sister genera in the Salicaceae family. In both lineages extant species are predominantly diploid. Genome analysis previously revealed that the two lineages originated from a common tetraploid ancestor. In this study, we conducted a syntenic comparison of the corresponding 19 chromosome members of the poplar and willow genomes. Our observations revealed that almost every chromosomal segment had a parallel paralogous segment elsewhere in the genomes, and the two lineages shared a similar syntenic pinwheel pattern for most of the chromosomes, which indicated that the two lineages diverged after the genome reorganization in the common progenitor. The pinwheel patterns showed distinct differences for two chromosome pairs in each lineage. Further analysis detected two major interchromosomal rearrangements that distinguished the karyotypes of willow and poplar. Chromosome I of willow was a conjunction of poplar chromosome XVI and the lower portion of poplar chromosome I, whereas willow chromosome XVI corresponded to the upper portion of poplar chromosome I. Scientists have suggested that Populus is evolutionarily more primitive than Salix. Therefore, we propose that, after the “salicoid” duplication event, fission and fusion of the ancestral chromosomes first give rise to the diploid progenitor of extant Populus species. During the evolutionary process, fission and fusion of poplar chromosomes I and XVI subsequently give rise to the progenitor of extant Salix species. This study contributes to an improved understanding of genome divergence after ancient genome duplication in closely related lineages of higher plants. PMID:27352946

  20. Major Chromosomal Rearrangements Distinguish Willow and Poplar After the Ancestral "Salicoid" Genome Duplication.

    PubMed

    Hou, Jing; Ye, Ning; Dong, Zhongyuan; Lu, Mengzhu; Li, Laigeng; Yin, Tongming

    2016-06-27

    Populus (poplar) and Salix (willow) are sister genera in the Salicaceae family. In both lineages extant species are predominantly diploid. Genome analysis previously revealed that the two lineages originated from a common tetraploid ancestor. In this study, we conducted a syntenic comparison of the corresponding 19 chromosome members of the poplar and willow genomes. Our observations revealed that almost every chromosomal segment had a parallel paralogous segment elsewhere in the genomes, and the two lineages shared a similar syntenic pinwheel pattern for most of the chromosomes, which indicated that the two lineages diverged after the genome reorganization in the common progenitor. The pinwheel patterns showed distinct differences for two chromosome pairs in each lineage. Further analysis detected two major interchromosomal rearrangements that distinguished the karyotypes of willow and poplar. Chromosome I of willow was a conjunction of poplar chromosome XVI and the lower portion of poplar chromosome I, whereas willow chromosome XVI corresponded to the upper portion of poplar chromosome I. Scientists have suggested that Populus is evolutionarily more primitive than Salix. Therefore, we propose that, after the "salicoid" duplication event, fission and fusion of the ancestral chromosomes first give rise to the diploid progenitor of extant Populus species. During the evolutionary process, fission and fusion of poplar chromosomes I and XVI subsequently give rise to the progenitor of extant Salix species. This study contributes to an improved understanding of genome divergence after ancient genome duplication in closely related lineages of higher plants.

  1. Nitrogen fertilizer and sewage sludge effects on hybrid poplars. Final report

    SciTech Connect

    Riha, S.R.; Senesac, G.P.; Naylor, L.

    1985-01-01

    Experiments conducted in the greenhouse compared the growth and nutrient and heavy metal uptake in two clones of hybrid poplar grown in soil amended with nitrogen fertilizer or sewage sludge. In addition, poplar responses to weed competition and to rooting prior to planting were investigated. Both fertilizer and sludge application increased poplar stem biomass. Weeds reduced poplar biomass. The large difference in root biomass of the two poplar clones may account for different effects weed and sludge application had on nutrient and heavy metal uptake in each clone. The relatively small root biomass of I-45/51 increased with increasing sludge application, as did the uptake of nutrients and heavy metals. The relatively large root biomass of clone NE-510 was reduced when weeds were present, as was nutrient and heavy metal uptake. Other results suggest that poplars with low root-to-stem ratios may be most affected by weed competition, especially after their first year, and that nitrogen fertilization may alleviate effects of weeds on their growth. Poplars grown in sludge-amended soil did not accumulate more of any nutrient or heavy metal studied compared to those grown in nitrogen-fertilized soil. 17 refs., 5 figs., 57 tabs.

  2. Divergence of the Dof gene families in poplar, Arabidopsis, and rice suggests multiple modes of gene evolution after duplication.

    PubMed

    Yang, Xiaohan; Tuskan, Gerald A; Cheng, Max Zong-Ming

    2006-11-01

    It is widely accepted that gene duplication is a primary source of genetic novelty. However, the evolutionary fate of duplicated genes remains largely unresolved. The classical Ohno's Duplication-Retention-Non/Neofunctionalization theory, and the recently proposed alternatives such as subfunctionalization or duplication-degeneration-complementation, and subneofunctionalization, each can explain one or more aspects of gene fate after duplication. Duplicated genes are also affected by epigenetic changes. We constructed a phylogenetic tree using Dof (DNA binding with one finger) protein sequences from poplar (Populus trichocarpa) Torr. & Gray ex Brayshaw, Arabidopsis (Arabidopsis thaliana), and rice (Oryza sativa). From the phylogenetic tree, we identified 27 pairs of paralogous Dof genes in the terminal nodes. Analysis of protein motif structure of the Dof paralogs and their ancestors revealed six different gene fates after gene duplication. Differential protein methylation was revealed between a pair of duplicated poplar Dof genes, which have identical motif structure and similar expression pattern, indicating that epigenetics is involved in evolution. Analysis of reverse transcription-PCR, massively parallel signature sequencing, and microarray data revealed that the paralogs differ in expression pattern. Furthermore, analysis of nonsynonymous and synonymous substitution rates indicated that divergence of the duplicated genes was driven by positive selection. About one-half of the motifs in Dof proteins were shared by non-Dof proteins in the three plants species, indicating that motif co-option may be one of the forces driving gene diversification. We provided evidence that the Ohno's Duplication-Retention-Non/Neofunctionalization, subfunctionalization/duplication-degeneration-complementation, and subneofunctionalization hypotheses are complementary with, not alternative to, each other.

  3. Phenylcoumaran Benzylic Ether Reductase Prevents Accumulation of Compounds Formed under Oxidative Conditions in Poplar Xylem[W

    PubMed Central

    Niculaes, Claudiu; Morreel, Kris; Kim, Hoon; Lu, Fachuang; McKee, Lauren S.; Ivens, Bart; Haustraete, Jurgen; Vanholme, Bartel; Rycke, Riet De; Hertzberg, Magnus; Fromm, Jorg; Bulone, Vincent; Polle, Andrea; Ralph, John; Boerjan, Wout

    2014-01-01

    Phenylcoumaran benzylic ether reductase (PCBER) is one of the most abundant proteins in poplar (Populus spp) xylem, but its biological role has remained obscure. In this work, metabolite profiling of transgenic poplar trees downregulated in PCBER revealed both the in vivo substrate and product of PCBER. Based on mass spectrometry and NMR data, the substrate was identified as a hexosylated 8–5-coupling product between sinapyl alcohol and guaiacylglycerol, and the product was identified as its benzyl-reduced form. This activity was confirmed in vitro using a purified recombinant PCBER expressed in Escherichia coli. Assays performed on 20 synthetic substrate analogs revealed the enzyme specificity. In addition, the xylem of PCBER-downregulated trees accumulated over 2000-fold higher levels of cysteine adducts of monolignol dimers. These compounds could be generated in vitro by simple oxidative coupling assays involving monolignols and cysteine. Altogether, our data suggest that the function of PCBER is to reduce phenylpropanoid dimers in planta to form antioxidants that protect the plant against oxidative damage. In addition to describing the catalytic activity of one of the most abundant enzymes in wood, we provide experimental evidence for the antioxidant role of a phenylpropanoid coupling product in planta. PMID:25238751

  4. The polyphenol oxidase gene family in poplar: phylogeny, differential expression and identification of a novel, vacuolar isoform.

    PubMed

    Tran, Lan T; Constabel, C Peter

    2011-10-01

    Polyphenol oxidases (PPOs) are oxidative enzymes that convert monophenols and o-diphenols to o-quinones using molecular oxygen. The quinone products are highly reactive following tissue damage and can interact with cellular constituents and cause oxidative browning and cross-linking. The induction of PPO in some plants as a result of wounding, herbivore attack, or pathogen infection has implicated them in defense. However, PPO-like enzymes that act as specific hydroxylases, for example in lignan and pigment biosynthesis, have also been discovered. Here, we present the first genome-enabled analysis of a PPO gene family. The Populus trichocarpa genome was found to contain a minimum of nine complete PPO genes, and seven of these were characterized further. The PPO gene family includes both recently duplicated and divergent sequences that are 36-98% identical at the amino acid level. Gene expression profiling in poplar tissues and organs revealed that the PPO genes are all differentially expressed during normal development, but that only a small subset of PPO genes are significantly upregulated by wounding, methyl jasmonate or pathogen infection. Our studies also identified PtrPPO13, a novel PPO gene that is predicted to encode an N-terminal signal peptide. Transient expression of green fluorescent protein fusions demonstrated its localization to the vacuolar lumen. Together, our findings show that the poplar PPO family is diverse and is likely linked to diverse physiological functions.

  5. Cell-Specific and Conditional Expression of Caffeoyl-Coenzyme A-3-O-Methyltransferase in Poplar1

    PubMed Central

    Chen, Cuiying; Meyermans, Hugo; Burggraeve, Bart; De Rycke, Riet M.; Inoue, Kentaro; De Vleesschauwer, Vera; Steenackers, Marijke; Van Montagu, Marc C.; Engler, Gilbert J.; Boerjan, Wout A.

    2000-01-01

    Caffeoyl coenzyme A-3-O-methyltransferase (CCoAOMT) plays an important role in lignin biosynthesis and is encoded by two genes in poplar (Populus trichocarpa). Here, we describe the expression pattern conferred by the two CCoAOMT promoters when fused to the gus-coding sequence in transgenic poplar (Populus tremula × Populus alba). Both genes were expressed similarly in xylem and differentially in phloem. In xylem, expression was preferentially observed in vessels and contact rays, whereas expression was barely detectable in storage rays and fibers, suggesting different routes to monolignol biosynthesis in the different xylem types. Furthermore, after wounding, fungal infection, and bending, the expression of both genes was induced concomitantly with de novo lignin deposition. Importantly, upon bending and leaning of the stem, the cell-specific expression pattern was lost, and both genes were expressed in all cell types of the xylem. CCoAOMT promoter activity correlated well with the presence of the CCoAOMT protein, as shown by immunolocalization. These expression data may explain, at least in part, the heterogeneity in lignin composition that is observed between cell types and upon different environmental conditions. PMID:10889235

  6. Phytoextraction of risk elements by willow and poplar trees.

    PubMed

    Kacálková, Lada; Tlustoš, Pavel; Száková, Jiřina

    2015-01-01

    To characterize the phytoextraction efficiency of two clones of willow trees (Salix x smithiana Willd., Salix rubens) and two clones of poplar trees (Populus nigra x maximowiczii, Populus nigra Wolterson) were planted in contaminated soil (0.4-2.0 mg Cd.kg(-1), 78-313 mg Zn.kg(-1), 21.3-118 mg Cu.kg(-1)). Field experiment was carried out in Czech Republic. The study investigated their ability to accumulate heavy metals (Cd, Zn, and Cu) in harvestable plant parts. The poplars produced higher amount of biomass than willows. Both Salix clones accumulated higher amount of Cd, Zn and Cu in their biomass (maximum 6.8 mg Cd.kg(-1), 909 mg Zn.kg(-1), and 17.7 mg Cu.kg(-1)) compared to Populus clones (maximum 2.06 mg Cd.kg(-1), 463 mg Zn.kg(-1), and 11.8 mg Cu.kg(-1)). There were no significant differences between clones of individual species. BCs for Cd and Zn were greater than 1 (the highest in willow leaves). BCs values of Cu were very low. These results indicate that Salix is more suitable plant for phytoextraction of Cd and Zn than Populus. The Cu phytoextraction potential of Salix and Populus trees was not confirmed in this experiment due to low soil availability of this element.

  7. Lignification in poplar tension wood lignified cell wall layers.

    PubMed

    Yoshinaga, Arata; Kusumoto, Hiroshi; Laurans, Françoise; Pilate, Gilles; Takabe, Keiji

    2012-09-01

    The lignification process in poplar tension wood lignified cell wall layers, specifically the S(1) and S(2) layers and the compound middle lamella (CML), was analysed using ultraviolet (UV) and transmission electron microscopy (TEM). Variations in the thickness of the gelatinous layer (G-layer) were also measured to clarify whether the lignified cell wall layers had completed their lignification before the deposition of G-layers, or, on the contrary, if lignification of these layers was still active during G-layer formation. Observations using UV microscopy and TEM indicated that both UV absorbance and the degree of potassium permanganate staining increased in the CML and S(1) and S(2) layers during G-layer formation, suggesting that the lignification of these lignified layers is still in progress during G-layer formation. In the context of the cell-autonomous monolignol synthesis hypothesis, our observations suggest that monolignols must go through the developing G-layer during the lignification of CML and the S(1) and S(2) layers. The alternative hypothesis of external synthesis (in the rays) does not require that monolignols go through the G-layer before being deposited in the CML, or the S(1) and S(2) layers. Interestingly, the previous observation of lignin in the poplar G-layer was not confirmed with the microscopy techniques used in the present study.

  8. Soils organic C sequestration under poplar and willow agroforestry systems

    NASA Astrophysics Data System (ADS)

    Gunina, Anna; Tariq, Azeem; Lamersdorf, Norbert

    2015-04-01

    Short rotation coppices (SRC) as monocultures or as agroforestry (AF) applications (e.g. alley cropping) are two techniques to implement forest into agricultural practices. Despite afforestation promotes soil carbon (C) accumulation, age and type of the tree stand can affect the C accumulation in different degrees. Here, we studied the impact of afforestation on C accumulation for: i) pure SCR of willow (Salix viminalis x Salix schwerinii) and poplar (Populus nigra x Populus maximowiczii) and ii) AF cropping system with willow. Forest systems have been established within the BEST agroforestry project in Germany. Adjacent agricultural field have been used as a control. Soil samples were collected in 2014, three years after plantation establishment, from three soil depths: 0-3, 3-20, and 20-30 cm. Total organic C, labile C (incubation of 20 g soil during 100 days with measuring of CO2) and aggregate structure were analysed. Additionally, density fractionation of the samples from 0-3 cm was applied to separate particulate organic matter (POM) and mineral fractions. Aggregates and density fractions were analyzed for C content. High input of plant litter as well as root exudates have led to increases of organic C in AF and SRC plots compare to cropland, mainly in the top 0-3 cm. The highest C content was found for willow SRC (18.2 g kg-1 soil), followed by willow-AF (15.6 g kg-1 soil), and poplar SRC (13.7 g kg-1 soil). Carbon content of cropland was 12.5 g kg-1 soil. Absence of ploughing caused increase portion of macroaggregates (>2000 μm) under SRC and AF in all soil layers as well as the highest percentage of C in that aggregate size class (70-80%). In contrast, C in cropland soil was mainly accumulated in small macroaggregates (250-2000 μm). Intensive mineralisation of fresh litter and old POM, taking place during first years of trees development, resulted to similar portions of free POM for willow AF, willow SRC and cropland (8%), and even lower ones for poplar

  9. Genomics of hybrid poplar (Populus trichocarpax deltoides) interacting with forest tent caterpillars (Malacosoma disstria): normalized and full-length cDNA libraries, expressed sequence tags, and a cDNA microarray for the study of insect-induced defences in poplar.

    PubMed

    Ralph, Steven; Oddy, Claire; Cooper, Dawn; Yueh, Hesther; Jancsik, Sharon; Kolosova, Natalia; Philippe, Ryan N; Aeschliman, Dana; White, Rick; Huber, Dezene; Ritland, Carol E; Benoit, François; Rigby, Tracey; Nantel, André; Butterfield, Yaron S N; Kirkpatrick, Robert; Chun, Elizabeth; Liu, Jerry; Palmquist, Diana; Wynhoven, Brian; Stott, Jeffrey; Yang, George; Barber, Sarah; Holt, Robert A; Siddiqui, Asim; Jones, Steven J M; Marra, Marco A; Ellis, Brian E; Douglas, Carl J; Ritland, Kermit; Bohlmann, Jörg

    2006-04-01

    As part of a genomics strategy to characterize inducible defences against insect herbivory in poplar, we developed a comprehensive suite of functional genomics resources including cDNA libraries, expressed sequence tags (ESTs) and a cDNA microarray platform. These resources are designed to complement the existing poplar genome sequence and poplar (Populus spp.) ESTs by focusing on herbivore- and elicitor-treated tissues and incorporating normalization methods to capture rare transcripts. From a set of 15 standard, normalized or full-length cDNA libraries, we generated 139,007 3'- or 5'-end sequenced ESTs, representing more than one-third of the c. 385,000 publicly available Populus ESTs. Clustering and assembly of 107,519 3'-end ESTs resulted in 14,451 contigs and 20,560 singletons, altogether representing 35,011 putative unique transcripts, or potentially more than three-quarters of the predicted c. 45,000 genes in the poplar genome. Using this EST resource, we developed a cDNA microarray containing 15,496 unique genes, which was utilized to monitor gene expression in poplar leaves in response to herbivory by forest tent caterpillars (Malacosoma disstria). After 24 h of feeding, 1191 genes were classified as up-regulated, compared to only 537 down-regulated. Functional classification of this induced gene set revealed genes with roles in plant defence (e.g. endochitinases, Kunitz protease inhibitors), octadecanoid and ethylene signalling (e.g. lipoxygenase, allene oxide synthase, 1-aminocyclopropane-1-carboxylate oxidase), transport (e.g. ABC proteins, calreticulin), secondary metabolism [e.g. polyphenol oxidase, isoflavone reductase, (-)-germacrene D synthase] and transcriptional regulation [e.g. leucine-rich repeat transmembrane kinase, several transcription factor classes (zinc finger C3H type, AP2/EREBP, WRKY, bHLH)]. This study provides the first genome-scale approach to characterize insect-induced defences in a woody perennial providing a solid platform for

  10. Systematic Characterization of the Zinc-Finger-Containing Proteins in the Mouse Transcriptome

    PubMed Central

    Ravasi, Timothy; Huber, Thomas; Zavolan, Mihaela; Forrest, Alistair; Gaasterland, Terry; Grimmond, Sean; Hume, David A.

    2003-01-01

    Zinc-finger-containing proteins can be classified into evolutionary and functionally divergent protein families that share one or more domains in which a zinc ion is tetrahedrally coordinated by cysteines and histidines. The zinc finger domain defines one of the largest protein superfamilies in mammalian genomes;46 different conserved zinc finger domains are listed in InterPro (http://www.ebi.ac.uk/InterPro). Zinc finger proteins can bind to DNA, RNA, other proteins, or lipids as a modular domain in combination with other conserved structures. Owing to this combinatorial diversity, different members of zinc finger superfamilies contribute to many distinct cellular processes, including transcriptional regulation, mRNA stability and processing, and protein turnover. Accordingly, mutations of zinc finger genes lead to aberrations in a broad spectrum of biological processes such as development, differentiation, apoptosis, and immunological responses. This study provides the first comprehensive classification of zinc finger proteins in a mammalian transcriptome. Specific detailed analysis of the SP/Krüppel-like factors and the E3 ubiquitin-ligase RING-H2 families illustrates the importance of such an analysis for a more comprehensive functional classification of large protein families. We describe the characterization of a new family of C2H2 zinc-finger-containing proteins and a new conserved domain characteristic of this family, the identification and characterization of Sp8, a new member of the Sp family of transcriptional regulators, and the identification of five new RING-H2 proteins. PMID:12819142

  11. Comparisons of Ethanol Extracts of Chinese Propolis (Poplar Type) and Poplar Gums Based on the Antioxidant Activities and Molecular Mechanism

    PubMed Central

    Zhang, Jianglin; Cao, Xueping; Ping, Shun; Wang, Kai; Shi, Jinhu; Zhang, Cuiping; Zheng, Huoqing; Hu, Fuliang

    2015-01-01

    The biological activities of propolis are varied from plant sources and the prominent antioxidant effects of Chinese propolis (poplar type) have been extensively reported. Oxidative stress is associated with inflammation and induces many diseases. In the study, to evaluate antioxidant capacities and clarify the underlying molecular mechanisms of ethanol extracts of Chinese propolis (EECP) and ethanol extracts of poplar gums (EEPG), we analyzed their compositions by HPLC, evaluating their free radical scavenging activities and reducing power by chemical analysis methods. Moreover, we studied the roles of EECP and EEPG on the elimination of ROS and expressions of antioxidant genes (HO-1, TrxR1, GCLM, and GCLC) in RAW264.7 cells. We further investigated the effects of MAPKs on the antioxidant genes expression by specific inhibitors. The nucleus translocation effects of Nrf2 were also measured by confocal microscopy analysis. The results indicated that EECP had higher TPC and FDC values but regarding TFC values were not significant. EECP also possessed more contents of 11 compounds than EEPG. Both phytochemical analysis and cell experiment reflected that EECP exerted stronger antioxidant activities than EEPG. EECP and EEPG enhanced endogenous antioxidant defenses by eliminating reactive oxygen species directly and activating Erk-Nrf2-HO1, GCLM, and TrxR1 signal pathways. PMID:25802536

  12. Cloning, Functional Expression, and Subcellular Localization of Multiple NADPH-Cytochrome P450 Reductases from Hybrid Poplar1

    PubMed Central

    Ro, Dae-Kyun; Ehlting, Jürgen; Douglas, Carl J.

    2002-01-01

    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 × 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 isolated from strains expressing CPR1/C4H or CPR2/C4H enhanced C4H activities approximately 10-fold relative to the C4H-only control strain, and catalyzed NADPH-dependent cytochrome c reduction. The divergent CPR isoforms (CPR1 and CPR2/3) contained entirely different N-terminal sequences, which are conserved in other plant CPRs and are diagnostic for two distinct classes of CPRs within the angiosperms. C-terminal green fluorescent protein fusions to CPR1 and CPR2 were constructed and expressed in both yeast and Arabidopsis. The fusion proteins expressed in yeast retained the ability to support C4H activity and, thus, were catalytically active. Both CPR::green fluorescent protein fusion proteins were strictly localized to the endoplasmic reticulum in transgenic Arabidopsis. The lack of localization of either isoform to chloroplasts, where P450s are known to be present, suggests that an alternative P450 reduction system may be operative in this organelle. Transcripts for the three poplar CPR genes were present ubiquitously in all tissues examined, but CPR2 showed highest expression in young leaf tissue. PMID:12481067

  13. Drought response transcriptomes are altered in poplar with reduced tonoplast sucrose transporter expression

    PubMed Central

    Xue, Liang-Jiao; Frost, Christopher J.; Tsai, Chung-Jui; Harding, Scott A.

    2016-01-01

    Transgenic Populus tremula x alba (717-1B4) plants with reduced expression of a tonoplast sucrose efflux transporter, PtaSUT4, exhibit reduced shoot growth compared to wild type (WT) under sustained mild drought. The present study was undertaken to determine whether SUT4-RNAi directly or indirectly altered poplar predisposition and/or response to changes in soil water availability. While sucrose and hexose levels were constitutively elevated in shoot organs, expression responses to drought were most altered in the root tips of SUT4-RNAi plants. Prior to any drought treatment, constitutively elevated transcript levels of abscisic acid biosynthetic genes and bark/vegetative storage proteins suggested altered metabolism in root tips of RNAi plants. Stronger drought-stimulation of stress-inducible genes encoding late-embryogenesis-abundant proteins in transgenic roots was consistent with increased vulnerability to soil drying. Transcript evidence suggested an RNAi effect on intercellular water trafficking by aquaporins in stem xylem during soil drying and recovery. Co-expression network analysis predicted altered integration of abscisic acid sensing/signaling with ethylene and jasmonate sensing/signaling in RNAi compared to WT roots. The overall conclusion is that steepened shoot-root sugar gradient in RNAi plants increased sensitivity of root tips to decreasing soil water availability. PMID:27641356

  14. Hydroxylated Metabolites of 4-Monochlorobiphenyl and Its Metabolic Pathway in Whole Poplar Plants

    PubMed Central

    Zhai, Guangshu; Lehmler, Hans-Joachim; Schnoor, Jerald L.

    2010-01-01

    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 × 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 showed poplar plants can metabolize CB3 into OH-CB3s. Three monohydroxy metabolites, including 2′-hydroxy-4-chlorobiphenyl (2′OH-CB3), 3′-hydroxy-4-chlorobiphenyl (3′OH-CB3) and 4′-hydroxy-4-chlorobiphenyl (4′OH-CB3), were identified in hydroponic solution and in different parts of poplar plant. The metabolite 4′OH-CB3 was the major product. In addition, there were two other unknown monohydroxy metabolites of CB3 found in whole poplar plants. Based on their physical and chemical properties, they are likely to be 2-hydroxy-4-chlorobiphenyl (2OH-CB3) and 3-hydroxy-4-chlorobiphenyl (3OH-CB3). Compared to the roots and leaves, the middle portion of the plant (the middle wood and bark) had higher concentrations of 2′OH-CB3, 3′OH-CB3 and 4′OH-CB3, which suggests that these hydroxylated metabolites of CB3 are easily translocated in poplars from roots to shoots. The total masses of 2′OH-CB3, 3′OH-CB3 and 4′OH-CB3 in whole poplar plants were much higher than those in solution, strongly suggesting that it is mainly the poplar plant itself which metabolizes CB3 to OH-CB3s. Finally, the data suggest that the metabolic pathway be via epoxide intermediates. PMID:20402517

  15. Assessing Changes in Soil Carbon Quantity and Chemistry in Short-Rotation Hybrid Poplar Plantations

    NASA Astrophysics Data System (ADS)

    Hoover, C. M.; Magrini, K. A.; Davis, M. F.

    2003-12-01

    There is increasing interest in using short-rotation woody biomass plantations as a source of fiber and as a carbon neutral energy supply. Willow, poplar, and alder are currently used in plantations in areas ranging from the Lake States to the Northwest. As with any cropping system, maintaining soil productivity through succeeding rotations is a key management goal. Where plantations are used to provide carbon sequestration benefits (i.e. bioenergy production), building and maintaining soil carbon stocks is of particular concern. We sampled three hybrid poplar farms in the Northwestern United States; all three farms are in the rain shadow of the Cascades and are on sandy soils. The farms share a similar land use history; originally sagebrush, the land was in annual crops such as peas, onions, and alfalfa, before conversion to poplar. At each farm, soil cores were taken from a field in annual crops, a first rotation poplar stand, and a second rotation poplar stand. Although results varied by farm, soil carbon concentrations were generally higher in the first and second rotation poplar stands than in the row-cropped fields; this was more pronounced in the 0-5 cm and 5-10 cm depths. There were no apparent declines in soil carbon concentration between the first and second rotations. Soil carbon concentrations under poplar were also higher than those in soils from native sagebrush, the original land cover. Analysis of the chemical composition of the carbon using pyrolysis molecular beam mass spectrometry indicates that by the second rotation, the chemical signature of the carbon resembled that found in materials taken from the poplar trees.

  16. Dechlorination of PCBs in the rhizosphere of Switchgrass and Poplar

    PubMed Central

    Meggo, Richard E.; Schnoor, Jerald L.; Hu, Dingfei

    2014-01-01

    Polychlorinated biphenyl (PCB) congeners (PCB 52, 77, and 153) singly and in mixture were spiked and aged in soil microcosms and subsequently planted with switchgrass (Panicum virgatum) or poplar (Populus deltoids x nigra DN34). The planted reactors showed significantly greater reductions in PCB parent compounds when compared to unplanted systems after 32 weeks. There was evidence of reductive dechlorination in both planted and unplanted systems, but the planted microcosms with fully developed roots and rhizospheres showed greater biotransformation than the unplanted reactors. These dechlorination products accounted for approximately all of the molar mass of parent compound lost. Based on the transformation products, reductive dechlorination pathways are proposed for rhizospheric biotransformation of PCB 52, 77, and 153. This is the first report of rhizosphere biotransformation pathways for reductive dechlorination in marginally aerobic, intermittently flooded soil as evidenced by a mass balance on transformation products. PMID:23603468

  17. Case history development of a hybrid poplar nursery at Reynolds Metals Company, Massena, New York. Final report

    SciTech Connect

    Marler, R.L.

    1981-11-01

    Intensive cultivation of fast-growing hardwoods, such as hybrid poplars, is a promising method of assuring adequate supplies of biomass for energy purposes. This report details the establishment of a hybrid poplar nursery on formerly unused land at the Reynolds Metals Company's reduction plant in Massena, NY and presents the results obtained during the first growing season. Cuttings from the nursery replanted during the Spring of 1982 are the first phase of a 600-acre hybrid poplar plantation at the Reynolds site.

  18. Development of the Poplar-Laccaria bicolor Ectomycorrhiza Modifies Root Auxin Metabolism, Signaling, and Response1

    PubMed Central

    Vayssières, Alice; Pěnčík, Ales; Felten, Judith; Kohler, Annegret; Ljung, Karin; Martin, Francis; Legué, Valérie

    2015-01-01

    Root systems of host trees are known to establish ectomycorrhizae (ECM) interactions with rhizospheric fungi. This mutualistic association leads to dramatic developmental modifications in root architecture, with the formation of numerous short and swollen lateral roots ensheathed by a fungal mantle. Knowing that auxin plays a crucial role in root development, we investigated how auxin metabolism, signaling, and response are affected in poplar (Populus spp.)-Laccaria bicolor ECM roots. The plant-fungus interaction leads to the arrest of lateral root growth with simultaneous attenuation of the synthetic auxin response element DR5. Measurement of auxin-related metabolites in the free-living partners revealed that the mycelium of L. bicolor produces high concentrations of the auxin indole-3-acetic acid (IAA). Metabolic profiling showed an accumulation of IAA and changes in the indol-3-pyruvic acid-dependent IAA biosynthesis and IAA conjugation and degradation pathways during ECM formation. The global analysis of auxin response gene expression and the regulation of AUXIN SIGNALING F-BOX PROTEIN5, AUXIN/IAA, and AUXIN RESPONSE FACTOR expression in ECM roots suggested that symbiosis-dependent auxin signaling is activated during the colonization by L. bicolor. Taking all this evidence into account, we propose a model in which auxin signaling plays a crucial role in the modification of root growth during ECM formation. PMID:26084921

  19. Development of the Poplar-Laccaria bicolor Ectomycorrhiza Modifies Root Auxin Metabolism, Signaling, and Response.

    PubMed

    Vayssières, Alice; Pěnčík, Ales; Felten, Judith; Kohler, Annegret; Ljung, Karin; Martin, Francis; Legué, Valérie

    2015-09-01

    Root systems of host trees are known to establish ectomycorrhizae (ECM) interactions with rhizospheric fungi. This mutualistic association leads to dramatic developmental modifications in root architecture, with the formation of numerous short and swollen lateral roots ensheathed by a fungal mantle. Knowing that auxin plays a crucial role in root development, we investigated how auxin metabolism, signaling, and response are affected in poplar (Populus spp.)-Laccaria bicolor ECM roots. The plant-fungus interaction leads to the arrest of lateral root growth with simultaneous attenuation of the synthetic auxin response element DR5. Measurement of auxin-related metabolites in the free-living partners revealed that the mycelium of L. bicolor produces high concentrations of the auxin indole-3-acetic acid (IAA). Metabolic profiling showed an accumulation of IAA and changes in the indol-3-pyruvic acid-dependent IAA biosynthesis and IAA conjugation and degradation pathways during ECM formation. The global analysis of auxin response gene expression and the regulation of AUXIN SIGNALING F-BOX PROTEIN5, AUXIN/IAA, and AUXIN RESPONSE FACTOR expression in ECM roots suggested that symbiosis-dependent auxin signaling is activated during the colonization by L. bicolor. Taking all this evidence into account, we propose a model in which auxin signaling plays a crucial role in the modification of root growth during ECM formation.

  20. Comparative Physiological and Proteomic Analysis Reveals the Leaf Response to Cadmium-Induced Stress in Poplar (Populus yunnanensis)

    PubMed Central

    Yang, Shihai; Zhou, Yanli; Dong, Chao; Ren, Jian; Sun, Xudong; Yang, Yongping

    2015-01-01

    Excess amounts of heavy metals are important environmental pollutants with significant ecological and nutritional effects. Cdmium (Cd) is of particular concern because of its widespread occurrence and high toxicity. We conducted physiological and proteomic analyses to improve our understanding of the responses of Populus yunnanensis to Cd stress. The plantlets experienced two apparent stages in their response to Cd stress. During the first stage, transiently induced defense-response molecules, photosynthesis- and energy-associated proteins, antioxidant enzymes and heat shock proteins (HSPs) accumulated to enhance protein stability and establish a new cellular homeostasis. This activity explains why plant photosynthetic capability during this period barely changed. During the second stage, a decline of ribulose-1, 5-bisphosphate carboxylase (RuBisCO) and HSP levels led to imbalance of the plant photosynthetic system. Additionally, the expression of Mitogen-activated protein kinase 3 (MPK3), Mitogen-activated protein kinase 6 (MPK6) and a homeobox-leucine zipper protein was higher in the second stage. Higher expression of caffeoyl-CoA O-methyltransferase (CCoAOMT) may regulate plant cell wall synthesis for greater Cd storage. These genes may be candidates for further research and use in genetic manipulation of poplar tolerance to Cd stress. PMID:26349064

  1. Effects of Heavy Metals and Arbuscular Mycorrhiza on the Leaf Proteome of a Selected Poplar Clone: A Time Course Analysis

    PubMed Central

    Lingua, Guido; Bona, Elisa; Todeschini, Valeria; Cattaneo, Chiara; Marsano, Francesco; Berta, Graziella; Cavaletto, Maria

    2012-01-01

    Arbuscular mycorrhizal (AM) fungi establish a mutualistic symbiosis with the roots of most plant species. While receiving photosynthates, they improve the mineral nutrition of the plant and can also increase its tolerance towards some pollutants, like heavy metals. Although the fungal symbionts exclusively colonize the plant roots, some plant responses can be systemic. Therefore, in this work a clone of Populus alba L., previously selected for its tolerance to copper and zinc, was used to investigate the effects of the symbiosis with the AM fungus Glomus intraradices on the leaf protein expression. Poplar leaf samples were collected from plants maintained in a glasshouse on polluted (copper and zinc contaminated) or unpolluted soil, after four, six and sixteen months of growth. For each harvest, about 450 proteins were reproducibly separated on 2DE maps. At the first harvest the most relevant effect on protein modulation was exerted by the AM fungi, at the second one by the metals, and at the last one by both treatments. This work demonstrates how importantly the time of sampling affects the proteome responses in perennial plants. In addition, it underlines the ability of a proteomic approach, targeted on protein identification, to depict changes in a specific pattern of protein expression, while being still far from elucidating the biological function of each protein. PMID:22761694

  2. Comparative Physiological and Proteomic Analysis Reveals the Leaf Response to Cadmium-Induced Stress in Poplar (Populus yunnanensis).

    PubMed

    Yang, Yunqiang; Li, Xiong; Yang, Shihai; Zhou, Yanli; Dong, Chao; Ren, Jian; Sun, Xudong; Yang, Yongping

    2015-01-01

    Excess amounts of heavy metals are important environmental pollutants with significant ecological and nutritional effects. Cdmium (Cd) is of particular concern because of its widespread occurrence and high toxicity. We conducted physiological and proteomic analyses to improve our understanding of the responses of Populus yunnanensis to Cd stress. The plantlets experienced two apparent stages in their response to Cd stress. During the first stage, transiently induced defense-response molecules, photosynthesis- and energy-associated proteins, antioxidant enzymes and heat shock proteins (HSPs) accumulated to enhance protein stability and establish a new cellular homeostasis. This activity explains why plant photosynthetic capability during this period barely changed. During the second stage, a decline of ribulose-1, 5-bisphosphate carboxylase (RuBisCO) and HSP levels led to imbalance of the plant photosynthetic system. Additionally, the expression of Mitogen-activated protein kinase 3 (MPK3), Mitogen-activated protein kinase 6 (MPK6) and a homeobox-leucine zipper protein was higher in the second stage. Higher expression of caffeoyl-CoA O-methyltransferase (CCoAOMT) may regulate plant cell wall synthesis for greater Cd storage. These genes may be candidates for further research and use in genetic manipulation of poplar tolerance to Cd stress.

  3. Physiological and transcriptional regulation in poplar roots and leaves during acclimation to high temperature and drought.

    PubMed

    Jia, Jingbo; Li, Shaojun; Cao, Xu; Li, Hong; Shi, Wenguang; Polle, Andrea; Liu, Tong-Xian; Peng, Changhui; Luo, Zhi-Bin

    2016-05-01

    To elucidate the physiological and transcriptional regulatory mechanisms that underlie the responses of poplars to high temperature (HT) and/or drought in woody plants, we exposed Populus alba × Populus tremula var. glandulosa saplings to ambient temperature (AT) or HT under 80 or 40% field capacities (FC), or no watering. HT increased the foliar total carbon (C) concentrations, and foliar δ(13) C and δ(18) O. HT triggered heat stress signaling via increasing levels of abscisic acid (ABA) and indole-3-acetic acid (IAA) in poplar roots and leaves. After perception of HT, poplars initiated osmotic adjustment by increasing foliar sucrose and root galactose levels. In agreement with the HT-induced heat stress and the changes in the levels of ABA and carbohydrates, we detected increased transcript levels of HSP18 and HSP21, as well as NCED3 in the roots and leaves, and the sugar transporter gene STP14 in the roots. Compared with AT, drought induced greater enhancement of foliar δ(13) C and δ(18) O in poplars at HT. Similarly, drought caused greater stimulation of the ABA and foliar glucose levels in poplars at HT than at AT. Correspondingly, desiccation led to greater increases in the mRNA levels of HSP18, HSP21, NCED3, STP14 and INT1 in poplar roots at HT than at AT. These results suggest that HT has detrimental effects on physiological processes and it induces the transcriptional regulation of key genes involved in heat stress responses, ABA biosynthesis and sugar transport and HT can cause greater changes in drought-induced physiological and transcriptional responses in poplar roots and leaves.

  4. Chloroplast parameters differ in wild type and transgenic poplars overexpressing gsh1 in the cytosol.

    PubMed

    Ivanova, L A; Ronzhina, D A; Ivanov, L A; Stroukova, L V; Peuke, A D; Rennenberg, H

    2009-07-01

    Poplar mutants overexpressing the bacterial genes gsh1 or gsh2 encoding the enzymes of glutathione biosynthesis are among the best-characterised transgenic plants. However, this characterisation originates exclusively from laboratory studies, and the performance of these mutants under field conditions is largely unknown. Here, we report a field experiment in which the wild-type poplar hybrid Populus tremula x P. alba and a transgenic line overexpressing the bacterial gene gsh1 encoding gamma-glutamylcysteine synthetase in the cytosol were grown for 3 years at a relatively clean (control) field site and a field site contaminated with heavy metals. Aboveground biomass accumulation was slightly smaller in transgenic compared to wild-type plants; soil contamination significantly decreased biomass accumulation in both wild-type and transgenic plants by more than 40%. Chloroplasts parameters, i.e., maximal diameter, projection area and perimeter, surface area and volume, surface/volume ratio and a two-dimensional form coefficient, were found to depend on plant type, leaf tissue and soil contamination. The greatest differences between wild and transgenic poplars were observed at the control site. Under these conditions, chloroplast sizes in palisade tissue of transgenic poplar significantly exceeded those of the wild type. In contrast to the wild type, palisade chloroplast volume exceeded that of spongy chloroplasts in transgenic poplars at both field sites. Chlorophyll content per chloroplast was the same in wild and transgenic poplars. Apparently, the increase in chloroplast volume was not connected to changes in the photosynthetic centres. Chloroplasts of transgenic poplar at the control site were more elongated in palisade cells and close to spherical in spongy mesophyll chloroplasts. At the contaminated site, palisade and spongy cell chloroplasts of leaves from transgenic trees and the wild type were the same shape. Transgenic poplars also had a smaller chloroplast

  5. Enantioselective Transport and Biotransformation of Chiral Hydroxylated Metabolites of Polychlorinated Biphenyls in Whole Poplar Plants

    PubMed Central

    2015-01-01

    Hydroxylated metabolites of polychlorinated biphenyls (OH-PCBs) have been found to be ubiquitous in the environment due to the oxidative metabolism of their parent PCBs. With more polarity, OH-PCBs may be more toxic and mobile than their parent compounds. However, the behavior and fate of OH-PCBs have been neglected in the environment because they are not the original contaminants. Some of these hydroxylated metabolites are chiral, and chiral compounds can be used to probe biological metabolic processes. Therefore, chiral OH-PCBs were selected to study their uptake, translocation, transformation, and enantioselectivity in plants in this work. Poplars (Populus deltoides × nigra, DN34), a model plant with complete genomic sequence, were hydroponically exposed to 5-hydroxy-2,2′,3,4′,6-pentachlorobiphenyl (5-OH-PCB91) and 5-hydroxy-2,2′,3,5′,6-pentachlorobiphenyl (5-OH-PCB95) for 10 days. Chiral 5-OH-PCB91 and 5-OH-PCB95 were clearly shown to be sorbed, taken up, and translocated in whole poplars, and they were detected in various tissues of whole poplars. However, the enantioselectivity of poplar for 5-OH-PCB91 and 5-OH-PCB95 proved to be quite different. The second-eluting enantiomer of OH-PCB95, separated on a chiral column (Phenomenex Lux Cellulose-1), was enantioselectively removed in whole poplar. Enantiomeric fractions in the middle xylem, top bark, top xylem, and stem, reached 0.803 ± 0.022, 0.643 ± 0.110, 0.835 ± 0.087, and 0.830 ± 0.029, respectively. Therefore, 5-OH-PCB95 was significantly enantioselectively biotransformed inside poplar tissues, in contrast to nearly racemic mixtures of 5-OH-PCB95 remaining in hydroponic solutions. Unlike 5-OH-PCB95, 5-OH-PCB91 remained nearly racemic in most tissues of whole poplars during 10 day exposure, suggesting the enantiomers of 5-OH-PCB91 were equally transported and metabolized in whole poplars. This is the first evidence of enantioselectivity of chiral OH-PCBs and suggests that poplars can

  6. Practical salinity management for leachate irrigation to poplar trees.

    PubMed

    Smesrud, Jason K; Duvendack, George D; Obereiner, James M; Jordahl, James L; Madison, Mark F

    2012-01-01

    Landfill leachate can be beneficially reused for irrigation of fiber crops with appropriate attention to nutrient and salinity management. The Riverbend Landfill in Western Oregon has been effectively practicing irrigation of landfill leachate to poplar trees since 1993. Over that time, the site has been adaptively managed to control salinity impacts to the tree crop while beneficially utilizing the applied water and nutrients during each growing season. Representative leachate irrigation water has ranged in concentration of total dissolved solids from 777 to 6,940 mg/L, chloride from 180 to 1,760 mg/L and boron from 3.2 to 7.3 mg/L. Annual leachate irrigation applications have also ranged between 102 and 812 mm/yr. Important conclusions from this site have included: 1) Appropriate tree clone selection and tree stand spacing, thinning, and harvest rotations are critical to maintaining a productive tree stand that is resilient and resistant to salt stress. The most effective combinations have included clones DN-34, OP-367, 184-411, 49-177, and 15-29 planted at spacing of 3.7-m x 1.8-m to 3.7-m x 3.7-m; 2) Leaf tissue boron levels are closely correlated to soil boron levels and can be managed with leaching. When leaf tissue boron levels exceed 200 to 250 mg/kg, signs of salt stress may emerge and should be monitored closely; 3) Salinity from leachate irrigation can be managed to sustain a healthy tree crop by controlling mass loading rates and providing appropriate irrigation blending if necessary. Providing freshwater irrigation following each leachate irrigation and targeting freshwater irrigation as 30 percent of total irrigation water applied has successfully controlled salt impacts to vegetation; and 4) Drip irrigation generally requires more careful attention to long-term soil salinity management than spray irrigation. Moving drip irrigation tubes periodically to prevent the formation of highly saline zones within the soil profile is important. In this paper, a

  7. Infection assays in Arabidopsis reveal candidate effectors from the poplar rust fungus that promote susceptibility to bacteria and oomycete pathogens.

    PubMed

    Germain, Hugo; Joly, David L; Mireault, Caroline; Plourde, Mélodie B; Letanneur, Claire; Stewart, Donald; Morency, Marie-Josée; Petre, Benjamin; Duplessis, Sébastien; Séguin, Armand

    2016-11-21

    Fungi of the Pucciniales order cause rust diseases which, altogether, affect thousands of plant species worldwide and pose a major threat to several crops. How rust effectors-virulence proteins delivered into infected tissues to modulate host functions-contribute to pathogen virulence remains poorly understood. Melampsora larici-populina is a devastating and widespread rust pathogen of poplar, and its genome encodes 1184 identified small secreted proteins that could potentially act as effectors. Here, following specific criteria, we selected 16 candidate effector proteins and characterized their virulence activities and subcellular localizations in the leaf cells of Arabidopsis thaliana. Infection assays using bacterial (Pseudomonas syringae) and oomycete (Hyaloperonospora arabidopsidis) pathogens revealed subsets of candidate effectors that enhanced or decreased pathogen leaf colonization. Confocal imaging of green fluorescent protein-tagged candidate effectors constitutively expressed in stable transgenic plants revealed that some protein fusions specifically accumulate in nuclei, chloroplasts, plasmodesmata and punctate cytosolic structures. Altogether, our analysis suggests that rust fungal candidate effectors target distinct cellular components in host cells to promote parasitic growth.

  8. [Canopy conductance characteristics of poplar in agroforestry system in west Liaoning Province of Northeast China].

    PubMed

    Li, Zheng; Niu, Li-Hua; Yuan, Feng-Hui; Guan, De-Xin; Wang, An-Zhi; Jin, Chang-Jie; Wu, Jia-Bing

    2012-11-01

    By using Granier' s thermal dissipation probe, the sap flow of poplar in a poplar-maize agroforestry system in west Liaoning was continuously measured, and as well, the environmental factors such as air temperature, air humidity, net radiation, wind speed, soil temperature, and soil moisture content were synchronically measured. Based on the sap flow data, the canopy conductance of poplar was calculated with simplified Penman-Monteith equation. In the study area, the diurnal variation of poplar' s canopy conductance showed a "single peak" curve, whereas the seasonal variation showed a decreasing trend. There was a negative logarithm relationship between the canopy conductance and vapor pressure deficit, with the sensitivity of canopy conductance to vapor pressure deficit change decreased gradually from May to September. The canopy conductance had a positive relationship with solar radiation. In different months, the correlation degree of canopy conductance with environmental factors differed. The vapor pressure deficit in the whole growth period of poplar was the most significant environmental factor correlated with the canopy conductance.

  9. Transcriptome Analysis of Poplar during Leaf Spot Infection with Sphaerulina spp.

    PubMed Central

    Foster, Adam J.; Pelletier, Gervais; Tanguay, Philippe; Séguin, Armand

    2015-01-01

    Diseases of poplar caused by the native fungal pathogen Sphaerulina musiva and related species are of growing concern, particularly with the increasing interest in intensive poplar plantations to meet growing energy demands. Sphaerulina musiva is able to cause infection on leaves, resulting in defoliation and canker formation on stems. To gain a greater understanding of the different responses of poplar species to infection caused by the naturally co-evolved Sphaerulina species, RNA-seq was conducted on leaves of Populus deltoides, P. balsamifera and P. tremuloides infected with S. musiva, S. populicola and a new undescribed species, Ston1, respectively. The experiment was designed to contain the pathogen in a laboratory environment, while replicating disease development in commercial plantations. Following inoculation, trees were monitored for disease symptoms, pathogen growth and host responses. Genes involved in phenylpropanoid, terpenoid and flavonoid biosynthesis were generally upregulated in P. balsamifera and P. tremuloides, while cell wall modification appears to play an important role in the defense of P. deltoides. Poplar defensive genes were expressed early in P. balsamifera and P. tremuloides, but their expression was delayed in P. deltoides, which correlated with the rate of disease symptoms development. Also, severe infection in P. balsamifera led to leaf abscission. This data gives an insight into the large differences in timing and expression of genes between poplar species being attacked by their associated Sphaerulina pathogen. PMID:26378446

  10. Antibiofilm and Antioxidant Activity of Propolis and Bud Poplar Resins versus Pseudomonas aeruginosa

    PubMed Central

    De Marco, Stefania; Piccioni, Miranda; Pagiotti, Rita

    2017-01-01

    Pseudomonas aeruginosa is a common biofilm-forming bacterial pathogen implicated in lung, skin, and systemic infections. Biofilms are majorly associated with chronic lung infection, which is the most severe complication in cystic fibrosis patients characterized by drug-resistant biofilms in the bronchial mucus with zones, where reactive oxygen species concentration is increased mainly due to neutrophil activity. Aim of this work is to verify the anti-Pseudomonas property of propolis or bud poplar resins extracts. The antimicrobial activity of propolis and bud poplar resins extracts was determined by MIC and biofilm quantification. Moreover, we tested the antioxidant activity by DPPH and neutrophil oxidative burst assays. In the end, both propolis and bud poplar resins extracts were able to inhibit P. aeruginosa biofilm formation and to influence both swimming and swarming motility. Moreover, the extracts could inhibit proinflammatory cytokine production by human PBMC and showed both direct and indirect antioxidant activity. This work is the first to demonstrate that propolis and bud poplar resins extracts can influence biofilm formation of P. aeruginosa contrasting the inflammation and the oxidation state typical of chronic infection suggesting that propolis or bud poplar resins can be used along with antibiotic as adjuvant in the therapy against P. aeruginosa infections related to biofilm. PMID:28127379

  11. Transcriptome Analysis of Poplar during Leaf Spot Infection with Sphaerulina spp.

    PubMed

    Foster, Adam J; Pelletier, Gervais; Tanguay, Philippe; Séguin, Armand

    2015-01-01

    Diseases of poplar caused by the native fungal pathogen Sphaerulina musiva and related species are of growing concern, particularly with the increasing interest in intensive poplar plantations to meet growing energy demands. Sphaerulina musiva is able to cause infection on leaves, resulting in defoliation and canker formation on stems. To gain a greater understanding of the different responses of poplar species to infection caused by the naturally co-evolved Sphaerulina species, RNA-seq was conducted on leaves of Populus deltoides, P. balsamifera and P. tremuloides infected with S. musiva, S. populicola and a new undescribed species, Ston1, respectively. The experiment was designed to contain the pathogen in a laboratory environment, while replicating disease development in commercial plantations. Following inoculation, trees were monitored for disease symptoms, pathogen growth and host responses. Genes involved in phenylpropanoid, terpenoid and flavonoid biosynthesis were generally upregulated in P. balsamifera and P. tremuloides, while cell wall modification appears to play an important role in the defense of P. deltoides. Poplar defensive genes were expressed early in P. balsamifera and P. tremuloides, but their expression was delayed in P. deltoides, which correlated with the rate of disease symptoms development. Also, severe infection in P. balsamifera led to leaf abscission. This data gives an insight into the large differences in timing and expression of genes between poplar species being attacked by their associated Sphaerulina pathogen.

  12. Genetic variation of hydraulic and wood anatomical traits in hybrid poplar and trembling aspen.

    PubMed

    Schreiber, Stefan G; Hacke, Uwe G; Hamann, Andreas; Thomas, Barb R

    2011-04-01

    Intensive forestry systems and breeding programs often include either native aspen or hybrid poplar clones, and performance and trait evaluations are mostly made within these two groups. Here, we assessed how traits with potential adaptive value varied within and across these two plant groups. Variation in nine hydraulic and wood anatomical traits as well as growth were measured in selected aspen and hybrid poplar genotypes grown at a boreal planting site in Alberta, Canada. Variability in these traits was statistically evaluated based on a blocked experimental design. We found that genotypes of trembling aspen were more resistant to cavitation, exhibited more negative water potentials, and were more water-use-efficient than hybrid poplars. Under the boreal field test conditions, which included major regional droughts, height growth was negatively correlated with branch vessel diameter (Dv ) in both aspen and hybrid poplars and differences in Dv were highly conserved in aspen trees from different provenances. Differences between the hybrid poplars and aspen provenances suggest that these two groups employ different water-use strategies. The data also suggest that vessel diameter may be a key trait in evaluating growth performance in a boreal environment.

  13. Evapotranspiration and crop coefficient of poplar and willow short-rotation coppice used as vegetation filter.

    PubMed

    Guidi, Werther; Piccioni, Emiliano; Bonari, Enrico

    2008-07-01

    Ten-day evapotranspiration (ETc) and crop coefficient (k(c)) of willow and poplar SRC used as vegetation filter and grown under fertilised (F) and unfertilised (NF) conditions, were determined for two successive growing seasons using volumetric lysimeters. During the first growing season, total ETc observed was, respectively, 620 (NF)-1190 (F)mm in willow and 590 (NF)-725 (F) in poplar. During the second growing season, ETc showed a general increase, mainly in fertilised lysimeters where it ranged between 890 (NF)-1790 mm (F) in willow and 710 (NF)-1100 mm (NF) in poplar. kc reached in both years its maximum between the end of August and the beginning of September. In 2004 maximum kc ranged from 1.25-2.84 in willow and 1.06-1.90 in poplar, whereas in 2005 it ranged from 1.97-5.30 in willow and 1.71-4.28 in poplar. ETc seemed to be strongly correlated to plant development and mainly dependent on its nutritional status rather than on the differences between the species.

  14. Impacts of transgenic poplar-cotton agro-ecosystems upon target pests and non-target insects under field conditions.

    PubMed

    Zhang, D J; Liu, J X; Lu, Z Y; Li, C L; Comada, E; Yang, M S

    2015-07-27

    Poplar-cotton agro-ecosystems are the main agricultural planting modes of cotton fields in China. With increasing acres devoted to transgenic insect-resistant poplar and transgenic insect-resistant cotton, studies examining the effects of transgenic plants on target and non-target insects become increasingly important. We systematically surveyed populations of both target pests and non-target insects for 4 different combinations of poplar-cotton eco-systems over 3 years. Transgenic Bt cotton strongly resisted the target insects Fall webworm moth [Hyphantria cunea (Drury)], Sylepta derogata Fabrieius, and American bollworm (Heliothis armigera), but no clear impact on non-target insect cotton aphids (Aphis gossypii). Importantly, intercrops containing transgenic Pb29 poplar significantly increased the inhibitory effects of Bt cotton on Fall webworm moth in ecosystem IV. Highly resistant Pb29 poplar reduced populations of the target pests Grnsonoma minutara Hubner and non-target insect poplar leaf aphid (Chaitophorus po-pulialbae), while Fall webworm moth populations were unaffected. We determined the effects of Bt toxin from transgenic poplar and cotton on target and non-target pests in different ecosystems of cotton-poplar intercrops and identified the synergistic effects of such combinations toward both target and non-target insects.

  15. Metal accumulation in poplar plant grown with industrial wastes.

    PubMed

    Giachetti, Giorgio; Sebastiani, Luca

    2006-06-01

    In this study the effects of different levels of industrial wastes on growth traits and metal accumulation in aerial portions were determined for Populusxeuramericana clone I-214. The experiment started in April 2003. Scions of Populusxeuramericana clone I-214, were grown outdoor near Pisa (Italy), in lisimeters filled with soil naturally present in the land around the experimental site, were daily drip irrigated, hand weeded, monthly fertilized, pruned for a unique shoot and cultivated with four increasing treatments: soil non-amended, soil amended with 4.8 kgm(-2), with 9.6 kgm(-2) and with 19.2 kgm(-2) of fresh tannery waste. The climatic parameters were daily recorded throughout the whole experiment. Growth relieves were performed during the growing season. After six months since the plantation of the scions, aerial portions of every plant were harvested for biomass and metal content analyses. Data demonstrated that the waste exerted beneficial effects on poplars mainly through a general increase of growth traits and that the nutrients relocation is the mechanisms involved in modulating growth rate. The concentration and the amount of the mineral elements analysed (N, P, K, Na, Ca, Mg, S, B, Fe, Mn, Cu, Zn, Cr) changed determinately among treatments, organs and position. We concluded that phytoremediation strategies of tannery wastes might be possible and sustainable for polar plantations in soil amended with non-hazardous levels of industrial waste, which maintain total heavy metals concentration close to background values.

  16. Bioavailability of mercury in East Fork Poplar Creek soils

    SciTech Connect

    Barnett, M.O.; Turner, R.R.

    1995-05-01

    The initial risk assessment for the East Fork Poplar Creek (EFPC) floodplain in Oak Ridge, Tennessee, a superfund site heavily contaminated with mercury, was based upon a reference dose for mercuric chloride, a soluble mercury compound not expected to be present in the floodplain, which is frequently saturated with water. Previous investigations had suggested mercury in the EFPC floodplain was less soluble and therefore less bioavailable than mercuric chloride, possibly making the results of the risk assessment unduly conservative. A bioavailability study, designed to measure the amount of mercury available for absorption in a child`s digestive tract, the most critical risk endpoint and pathway, was performed on twenty soils from the EFPC floodplain. The average percentage of mercury released during the study for the twenty soils was 5.3%, compared to 100% of the compound mercuric chloride subjected to the same conditions. Alteration of the procedure to test additional conditions possible during soil digestion did not appreciably alter the results. Therefore, use of a reference dose for mercuric chloride in the EFPC risk assessment without inclusion of a corresponding bioavailability factor may be unduly conservative.

  17. Genomics Mechanisms of Carbon Allocation and Partitioning in Poplar

    SciTech Connect

    Kirst, Matias; Peter, Gary; Martin, Timothy

    2009-07-30

    The genetic control of carbon allocation and partitioning in woody perennial plants is poorly understood despite its importance for carbon sequestration. It is also unclear how environmental cues such as nitrogen availability impact the genes that regulate growth, and biomass allocation and wood composition in trees. To address these questions we phenotyped 396 clonally replicated genotypes of an interspecific pseudo-backcross pedigree of Populus for wood composition and biomass traits in above and below ground organs. The loci that regulate growth, carbon allocation and partitioning under two nitrogen conditions were identified, defining the contribution of environmental cues to their genetic control. Fifty-seven quantitative trait loci (QTL) were identified for twenty traits analyzed. The majority of QTL are specific to one of the two nitrogen treatments, demonstrating significant nitrogen-dependent genetic control. A highly significant genetic correlation was observed between plant growth and lignin/cellulose composition, and QTL co-localization identified the genomic position of potential pleiotropic regulators. Gene expression analysis of all poplar genes was also characterized in differentiating xylem, whole-roots and developing leaves of 192 of the segregating population. By integrating the QTL and gene expression information we identified genes that regulate carbon partitioning and several biomass growth related properties. The work developed in this project resulted in the publication of three book chapters, four scientific articles (three others currently in preparation), 17 presentations in international conferences and two provisional patent applications.

  18. BIOLOGICAL MONITORING PROGRAM FOR EAST FORK POPLAR CREEK

    SciTech Connect

    ADAMS, S.M.; ASHWOOD, T.L.; BEATY, T.W.; BRANDT, C.C.

    1997-10-24

    In May 1985, a National Pollutant Discharge Elimination System (NPDES) permit was issued for the Oak Ridge Y-12 Plant. As a condition of the permit a Biological Monitoring and Abatement Program (BMAP) was developed to demonstrate that the effluent limitations established for the Y- 12 Plant protect the classified uses of the receiving stream (East Fork Poplar Creek; EFPC), in particular, the growth and propagation of aquatic life (Lear et al. 1989). A second objective of the BMAP is to document the ecological effects resulting from the implementation of a water pollution control program designed to eliminate direct discharges of wastewaters to EFPC and to minimize the inadvertent release of pollutants to the environment. Because of the complex nature of the discharges to EFPC and the temporal and spatial variability in the composition of the discharges, a comprehensive, integrated approach to biological monitoring was developed. A new permit was issued to the Y-12 Plant on April 28, 1995 and became effective on July 1, 1995. Biological monitoring continues to be required under the new permit. The BMAP consists of four major tasks that reflect different but complementary approaches to evaluating the effects of the Y-12 Plant discharges on the aquatic integrity of EFPC. These tasks are (1) toxicity monitoring, (2) biological indicator studies, (3) bioaccumulation studies, and (4) ecological surveys of the periphyton, benthic macroinvertebrate, and fish communities.

  19. Biological monitoring program for East Fork Poplar Creek

    SciTech Connect

    Adams, S.M.; Ashwood, T.L.; Beaty, T.W.; Brandt, C.C.; Christensen, S.W.; Cicerone, D.S.; Greeley, M.S. Jr.; Hill, W.R.; Kszos, L.S.

    1997-04-18

    In May 1985, a National Pollutant Discharge Elimination System (NPDES) permit was issued for the Oak Ridge Y-12 Plant. As a condition of the permit, a Biological Monitoring and Abatement Program (BMAP) was developed to demonstrate that the effluent limitations established for the Y-12 Plant protect the classified uses of the receiving stream (East Fork Poplar Creek; EFPC), in particular, the growth and propagation of aquatic life (Lear et al. 1989). A second objective of the BMAP is to document the ecological effects resulting from the implementation of a water pollution control program designed to eliminate direct discharges of wastewaters to EFPC and to minimize the inadvertent release of pollutants to the environment. Because of the complex nature of the discharges to EFPC and the temporal and spatial variability in the composition of the discharges, a comprehensive, integrated approach to biological monitoring was developed. A new permit was issued to the Y-12 Plant on April 28, 1995 and became effective on July 1, 1995. Biological monitoring continues to be required under the new permit. The BMAP consists of four major tasks that reflect different but complementary approaches to evaluating the effects of the Y-12 Plant discharges on the aquatic integrity of EFPC. These tasks are (1) toxicity monitoring, (2) biological indicator studies, (3) bioaccumulation studies, and (4) ecological surveys of the periphyton, benthic macroinvertebrate, and fish communities.

  20. BIOLOGICAL MONITORING PROGRAM FOR EAST FORK POPLAR CREEK

    SciTech Connect

    ADAMS, S.M.; BEATY, T.W.; BRANDT, C.C.; CHRISTENSEN, S.W.; CICERONE, D.S.

    1998-09-09

    In May 1985, a National Pollutant Discharge Elimination System (NPDES) permit was issued for the Oak Ridge Y-12 Plant. As a condition of the permit, a Biological Monitoring and Abatement Program (BMAP) was developed to demonstrate that the effluent limitations established for the Y-12 Plant protect the classified uses of the receiving stream (East Fork Poplar Creek; EFPC), in particular, the growth and propagation of aquatic life (Lear et al. 1989). A second objective of the BMAP is to document the ecological effects resulting from the implementation of a water pollution control program designed to eliminate direct discharges of wastewaters to EFPC and to minimize the inadvertent release of pollutants to the environment. Because of the complex nature of the discharges to EFPC and the temporal and spatial variability in the composition of the discharges, a comprehensive, integrated approach to biological monitoring was developed. A new permit was issued to the Y-12 Plant on April 28, 1995 and became effective on July 1, 1995. Biological monitoring continues to be required under the new permit. The BMAP consists of four major tasks that reflect different but complementary approaches to evaluating the effects of the Y-12 Plant discharges on the aquatic integrity of EFPC. These tasks are (1) toxicity monitoring, (2) biological indicator studies, (3) bioaccumulation studies, and (4) ecological surveys of the periphyton, benthic macroinvertebrate, and fish communities.

  1. Daytime and nighttime wind differentially affects hydraulic properties and thigmomorphogenic response of poplar saplings.

    PubMed

    Huang, Ping; Wan, Xianchong; Lieffers, Victor J

    2016-05-01

    This study tested how wind in daytime and nighttime affects hydraulic properties and thigmomorphogenic response of poplar saplings. It shows that wind in daytime interrupted water balance of poplar plants by aggravating cavitation in the stem xylem under high xylem tension in the daytime, reducing water potential in midday and hence reducing gas exchange, including stomatal conductance and CO2 assimilation. The wind blowing in daytime significantly reduced plant growth, including height, diameter, leaf size, leaf area, root and whole biomass, whereas wind blowing in nighttime only caused a reduction in radial and height growth at the early stage compared with the control but decreased height:diameter ratios. In summary, the interaction between wind loading and xylem tension exerted a negative impact on water balance, gas exchanges and growth of poplar plants, and wind in nighttime caused only a small thigmomorphogenic response.

  2. Effect of lignocellulosic composition and structure on the bioethanol production from different poplar lines.

    PubMed

    Duan, Xiaojian; Zhang, Changbo; Ju, Xuehai; Li, Qiongcui; Chen, Shouyi; Wang, Jingan; Liu, Zhongqi

    2013-07-01

    Branches from three transgenic poplar lines and their wild type line 107 were used to study the effect of lignocellulosic composition and structure on the production of glucose and ethanol. Experimental results showed that the transgenic line 18-1 had the high cellulose content and amorphous fibril structure. After poplar meals were pretreated with 10% NaOH and a mixture of hydrogen peroxide and acetic acid, their lateral order index decreased significantly. The highest glucose yield in enzymatic hydrolysis and ethanol yield from the substrate of 18-1 was much higher than that from feedstock of 107 by 192.7% and 108.7%, respectively. Scanning electron microscopy images confirmed that lignocellulose from the 18-1 could be destroyed by chemicals more easily than those from other lines. These results demonstrated that changing lignocellulose structure could be more effective on improving the digestibility and enzymatic hydrolysis of poplar biomass than increasing the cellulose content in biomass.

  3. Effect of autohydrolysis on the wettability, absorbility and further alkali impregnation of poplar wood chips.

    PubMed

    Xu, Ningpan; Liu, Wei; Hou, Qingxi; Wang, Peiyun; Yao, Zhirong

    2016-09-01

    Autohydrolysis with different severity factors was performed on poplar wood chips prior to pulping, and the wettability, absorbility and the following impregnation of NaOH solution for the poplar wood chips were then investigated. The results showed that after autohydrolysis pretreatment the porosity, shrinkage and fiber saturation point (FSP) of the poplar wood chips were increased, while the surface contact angle decreased as the severity factor was increased. The autohydrolyzed chips absorbed more NaOH in impregnation that resulted in a low NaOH concentration in the bulk impregnation liquor (i.e., the impregnation liquor outside wood chips), while the concentration in the entrapped liquor (i.e., the impregnation liquor inside wood chips) was increased. Autohydrolysis substantially improved the effectiveness of alkali impregnation.

  4. Transgenic Hybrid Poplar for Sustainable and Scalable Production of the Commodity/Specialty Chemical, 2-Phenylethanol

    PubMed Central

    Costa, Michael A.; Marques, Joaquim V.; Dalisay, Doralyn S.; Herman, Barrington; Bedgar, Diana L.; Davin, Laurence B.; Lewis, Norman G.

    2013-01-01

    Fast growing hybrid poplar offers the means for sustainable production of specialty and commodity chemicals, in addition to rapid biomass production for lignocellulosic deconstruction. Herein we describe transformation of fast-growing transgenic hybrid poplar lines to produce 2-phenylethanol, this being an important fragrance, flavor, aroma, and commodity chemical. It is also readily converted into styrene or ethyl benzene, the latter being an important commodity aviation fuel component. Introducing this biochemical pathway into hybrid poplars marks the beginnings of developing a platform for a sustainable chemical delivery system to afford this and other valuable specialty/commodity chemicals at the scale and cost needed. These modified plant lines mainly sequester 2-phenylethanol via carbohydrate and other covalently linked derivatives, thereby providing an additional advantage of effective storage until needed. The future potential of this technology is discussed. MALDI metabolite tissue imaging also established localization of these metabolites in the leaf vasculature. PMID:24386157

  5. Poplar plantation has the potential to alter the water balance in semiarid Inner Mongolia.

    PubMed

    Wilske, Burkhard; Lu, Nan; Wei, Long; Chen, Shiping; Zha, Tonggang; Liu, Chenfeng; Xu, Wenting; Noormets, Asko; Huang, Jianhui; Wei, Yafen; Chen, Jun; Zhang, Zhiqiang; Ni, Jian; Sun, Ge; Guo, Kirk; McNulty, Steve; John, Ranjeet; Han, Xingguo; Lin, Guanghui; Chen, Jiquan

    2009-06-01

    Poplar plantation is the most dominant broadleaf forest type in northern China. Since the mid-1990s plantation was intensified to combat desertification along China's northwestern border, i.e., within Inner Mongolia (IM). This evoked much concern regarding the ecological and environmental effects on areas that naturally grow grass or shrub vegetation. To highlight potential consequences of large-scale poplar plantations on the water budget within semiarid IM, we compared the growing season water balance (evapotranspiration (ET) and precipitation (PPT)) of a 3-yr old poplar plantation (Kp(3)) and a natural shrubland (Ks) in the Kubuqi Desert in western IM, and a 6-yr old poplar plantation (Bp(6)) growing under sub-humid climate near Beijing. The results showed that, despite 33% lower PPT at Kp(3), ET was 2% higher at Kp(3) (228 mm) as compared with Ks (223 mm) in May-September 2006. The difference derived mainly from higher ET at the plantation during drier periods of the growing season, which also indicated that the poplars must have partly transpired groundwater. Estimated growing season ET at Bp(6) was about 550 mm and more than 100% higher than at Kp(3). It is estimated that increases in leaf area index and net radiation at Kp(3) provide future potential for the poplars in Kubuqi to exceed the present ET and ET of the natural shrubland by 100-200%. These increases in ET are only possible through the permanent use of groundwater either directly by the trees or through increased irrigation. This may significantly change the water balance in the area (e.g., high ET at the cost of a reduction in the water table), which renders large-scale plantations a questionable tool in sustainable arid-land management.

  6. Energy partitioning and surface resistance of a poplar plantation in northern China

    NASA Astrophysics Data System (ADS)

    Kang, M.; Zhang, Z.; Noormets, A.; Fang, X.; Zha, T.; Zhou, J.; Sun, G.; McNulty, S. G.; Chen, J.

    2015-07-01

    Poplar (Populus sp.) plantations have been, on the one hand, broadly used in northern China for urban greening, combating desertification, as well as for paper and wood production. On the other hand, such plantations have been questioned occasionally for their possible negative impacts on water availability due to the higher water-use nature of poplar trees compared with other tree species in water-limited dryland regions. To further understand the acclimation of poplar species to semiarid environments and to evaluate the potential impacts of these plantations on the broader context of the region's water supply, we examine the variability of bulk resistance parameters and energy partitioning in a poplar (Populus euramericana cv. "74/76") plantation located in northern China over a 4-year period, encompassing both dry and wet conditions. The partitioning of available energy to latent heat flux (LE) decreased from 0.62 to 0.53 under mediated meteorological drought by irrigation applications. A concomitant increase in sensible heat flux (H) resulted in the increase of a Bowen ratio from 0.83 to 1.57. Partial correlation analysis indicated that surface resistance (Rs) normalized by leaf area index (LAI; Rs:LAI) increased by 50 % under drought conditions and was the dominant factor controlling the Bowen ratio. Furthermore, Rs was the main factor controlling LE during the growing season, even in wet years, as indicated by the decoupling coefficient (Ω = 0.45 and 0.39 in wet and dry years, respectively). Rs was also a major regulator of the LE / LEeq ratio, which decreased from 0.81 in wet years to 0.68 in dry years. All physiological and bioclimatological metrics indicated that the water demands of the poplar plantation were greater than the amount available through precipitation, highlighting the poor match of a water-intensive species like poplar for this water-limited region.

  7. Uptake of ferrocyanide in willow and poplar trees in a long term greenhouse experiment.

    PubMed

    Dimitrova, Tsvetelina; Repmann, Frank; Raab, Thomas; Freese, Dirk

    2015-04-01

    Phytoremediation of sites contaminated with iron cyanides can be performed using poplar and willow trees. Poplar and willow trees were grown in potting substrate spiked with ferrocyanide concentrations of up to 2,000 mg kg(-1) for 4 and 8 weeks respectively. Soil solution and leaf tissue of different age were sampled for total cyanide analysis every week. Chlorophyll content in the leaves was determined to quantify cyanide toxicity. Results showed that cyanide in the soil solution of spiked soils differed between treatments and on weekly basis and ranged from 0.5 to 1,200 mg l(-1). The maximum cyanide content in willow and poplar leaves was 518 mg kg(-1) fresh weight (FW) and 148 mg kg(-1) FW respectively. Cyanide accumulated in the leaves increased linearly with increasing cyanide concentration in the soil solution. On the long term, significantly more cyanide was accumulated in old leaf tissue than in young tissue. Chlorophyll content in poplar decreased linearly with increasing cyanide in the soil solution and in leaf tissue, and over time. The inhibitory concentration (IC50) value for poplars after 4 weeks of exposure was 173 mg l(-1) and for willow after 8 weeks of exposure-768 mg l(-1). Results show that willows tolerate much more cyanide and over a longer period than poplars, making them very appropriate for remediating sites highly contaminated with iron cyanides.

  8. Physical and chemical characterizations of corn stover and poplar solids resulting from leading pretreatment technologies.

    PubMed

    Kumar, Rajeev; Mago, Gaurav; Balan, Venkatesh; Wyman, Charles E

    2009-09-01

    In order to investigate changes in substrate chemical and physical features after pretreatment, several characterizations were performed on untreated (UT) corn stover and poplar and their solids resulting pretreatments by ammonia fiber expansion (AFEX), ammonia recycled percolation (ARP), controlled pH, dilute acid, flowthrough, lime, and SO(2) technologies. In addition to measuring the chemical compositions including acetyl content, physical attributes determined were biomass crystallinity, cellulose degree of polymerization, cellulase adsorption capacity of pretreated solids and enzymatically extracted lignin, copper number, FT-IR responses, scanning electron microscopy (SEM) visualizations, and surface atomic composition by electron spectroscopy of chemical analysis (ESCA). Lime pretreatment removed the most acetyl groups from both corn stover and poplar, while AFEX removed the least. Low pH pretreatments depolymerized cellulose and enhanced biomass crystallinity much more than higher pH approaches. Lime pretreated corn stover solids and flowthrough pretreated poplar solids had the highest cellulase adsorption capacity, while dilute acid pretreated corn stover solids and controlled pH pretreated poplar solids had the least. Furthermore, enzymatically extracted AFEX lignin preparations for both corn stover and poplar had the lowest cellulase adsorption capacity. ESCA results showed that SO(2) pretreated solids had the highest surface O/C ratio for poplar, but for corn stover, the highest value was observed for dilute acid pretreatment with a Parr reactor. Although dependent on pretreatment and substrate, FT-IR data showed that along with changes in cross linking and chemical changes, pretreatments may also decrystallize cellulose and change the ratio of crystalline cellulose polymorphs (Ialpha/Ibeta).

  9. Effect of sprayer settings on spray drift during pesticide application in poplar plantations (Populus spp.).

    PubMed

    Grella, Marco; Marucco, Paolo; Manzone, Marco; Gallart, Montserrat; Balsari, Paolo

    2017-02-01

    This study assessed spray drift generated by sprayer settings commonly used for pesticide application in poplar plantations (Populus spp.). Tests were conducted per the ISO 22866 methodology using a mounted air-assisted sprayer (Tifone VRP600) equipped with a swivel-cannon air conveyor (model Cannone 50S). Trials evaluated sprayer settings, combinations of nozzle types, airflow rates, and air direction in both adult and young poplar plantations. Overall, spray drift amounts registered downwind of poplar plantations were less than those obtained to derive reference drift curves during the EU Plant Protection Product registration process that used late-growth-stage fruit crops. In the adult poplar plantation, Venturi nozzles (TVI 8004 red) yielded the highest drift reductions compared to reference sprayer setting, especially at distances farthest from the sprayed area (86% between 40 and 47m). Highest total drift reductions were achieved when conventional nozzles (1.81mm ceramic disc-core) were combined with their spray direction modified for an inclined cannon spray unit. Alternatively, the young poplar plantation showed no drift reduction for distances farthest from the sprayed area, regardless of sprayer settings, which likely resulted from lower foliage density and widely-spaced rows. Yet, both Venturi nozzles combined with high fan flow rates and conventional nozzles combined with reduced fan flow rate showed total spray drift reductions of over 70% within the downwind sampling area. These experimental results represent the first set of data on spray drift amounts in poplar plantations, which is key for defining the reference curves and best practices to reduce spray drift in tall tree plantations.

  10. Case history development of a hybrid poplar nursery at Reynolds Metals Company, Massena, NY. Final report

    SciTech Connect

    Marler, R.L.

    1983-03-01

    The methods used to establish the hybrid poplar nursery and the results obtained in the first year's operation are discussed. It also documents the history of the project. Hybrid poplar clones were established in the nursery in 1980 and their growth performance was evaluated after one growing season. The results were most promising. The mean survivability rate ranged from 84.92% to 90.58% per clone, while the clone height growth ranged from 58.16 inches to 76.47 inches over the first growing season. Approximately 71,000 cuttings were estimated to be available for outplanting during the Spring of 1982.

  11. Phytostimulation of poplars and Arabidopsis exposed to silver nanoparticles and Ag⁺ at sublethal concentrations.

    PubMed

    Wang, Jing; Koo, Yeonjong; Alexander, Anne; Yang, Yu; Westerhof, Samantha; Zhang, Qingbo; Schnoor, Jerald L; Colvin, Vicki L; Braam, Janet; Alvarez, Pedro J J

    2013-05-21

    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). Whereas all forms of silver were phytotoxic above a specific concentration, a stimulatory effect was observed on root elongation, fresh weight, and evapotranspiration of both plants at a narrow range of sublethal concentrations (e.g., 1 mg/L of 25 nm AgNPs for poplar). Plants were most susceptible to the toxic effects of Ag(+) (1 mg/L for poplar, 0.05 mg/L for Arabidopsis), but AgNPs also showed some toxicity at higher concentrations (e.g., 100 mg/L of 25 nm AgNPs for poplar, 1 mg/L of 5 nm AgNPs for Arabidopsis) and this susceptibility increased with decreasing AgNP size. Both poplars and Arabidopsis accumulated silver, but silver distribution in shoot organs varied between plant species. Arabidopsis accumulated silver primarily in leaves (at 10-fold higher concentrations than in the stem or flower tissues), whereas poplars accumulated silver at similar concentrations in leaves and stems. Within the particle subinhibitory concentration range, silver accumulation in poplar tissues increased with exposure concentration and with smaller AgNP size. However, compared to larger AgNPs, the faster silver uptake associated with smaller AgNPs was offset by their toxic effect on evapotranspiration, which was exerted at lower concentrations (e.g., 1 mg/L of 5 nm AgNPs for poplar). Overall, the observed phytostimulatory effects preclude generalizations about the phytotoxicity of AgNPs and encourage further mechanistic research.

  12. Some important physical properties of laminated veneer lumber (Lvl) made from oriental beech and Lombardy poplar

    NASA Astrophysics Data System (ADS)

    Kılıç, Murat

    2012-09-01

    This study examined some physical characteristics of laminated veneer lumber (LVL) obtained in different compositions from cut veneers of Oriental beech (Fagus Orientalis Lipsky) and Lombardy poplar (Populus nigra) with thicknesses of 4 mm and 5 mm. Five each beech and poplar trees were felled with this objective. The PVAc (Kleiberit 303) and PU (Bizon Timber PU-Max Express) types of adhesive were used in lamination. The air-dry and oven dry densities, cell wall density and porosity, the value of volume density, shrinkage in a tangential and radial direction and volume swelling amounts were determined by preparing the specimens in accordance with the standards.

  13. Effect of hybrid poplar trees on microbial populations important to hazardous waste bioremediation

    SciTech Connect

    Jordahl, J.L.; Foster, L.; Schnoor, J.L.; Alvarez, P.J.J.

    1997-06-01

    Microbial concentrations of denitrifiers, pseudomonads, and monoaromatic petroleum hydrocarbon (BTX) degraders were significantly higher (p < 0.1) in soil samples from the rhizosphere of poplar trees than in adjacent agricultural soils, and atrazine degraders were found only in one rhizosphere sample. The relative abundance of these phenotypes (as a fraction of total heterotrophs) was not significantly different between rhizosphere and surrounding soils. Therefore, the poplar rhizosphere enhanced the growth of microbial populations that participate in natural bioremediation without exerting selective pressure for them.

  14. Inhibition of Cytochromes P450 and the Hydroxylation of 4-Monochlorobiphenyl in Whole Poplar

    PubMed Central

    Zhai, Guangshu; Lehmler, Hans-Joachim; Schnoor, Jerald L.

    2013-01-01

    Cytochromes P450 (CYPs) are potential enzymes responsible for hydroxylation of many xenobiotics and endogenous chemicals in living organisms. It has been found that 4-monochlorobiphenyl (PCB3), mainly an airborne pollutant, can be metabolized to hydroxylated transformation products (OH-PCB3s) in whole poplars. However, the enzymes involved in the hydroxylation of PCB3 in whole poplars have not been identified. Therefore, two CYP suicide inhibitors, 1-aminobenzotriazole (ABT) and 17-octadecynoic acid (ODYA), were selected to probe the hydroxylation reaction of PCB3 in whole poplars in this work. Poplars (Populus deltoides × nigra, DN34) were exposed to PCB3 with or without inhibitor for 11 days. Results showed both ABT and ODYA can decrease the concentrations and yields of five OH-PCB3s in different poplar parts via the inhibition of CYPs. Furthermore, both ABT and ODYA demonstrated a dose-dependent relationship to the formation of OH-PCB3s in whole poplars. The higher the inhibitor concentrations, the lower the total yields of OH-PCB3s. For ABT spiked-additions, the total mass yield of five OH-PCB3s was inhibited by a factor of 1.6 times at an ABT concentration of 2.5 mg L−1, 4.0 times at 12.5 mg L−1, and 7.0 times at 25 mg L−1. For the inhibitor ODYA, the total mass of five OH-PCB3s was reduced by 2.1 times compared to the control at an ODYA concentration of 2.5 mg L−1. All results pointed to the conclusion that CYP enzymes were the agents which metabolized PCB3 to OH-PCB3s in whole poplars because suicide CYP inhibitors ABT and ODYA both led to sharp decreases of OH-PCB3s formation in whole poplars. A dose-response curve for each of the suicide inhibitors was developed. PMID:23320482

  15. Nutrient cycling for biomass: Interactive proteomic/transcriptomic networks for global carbon management processes within poplar-mycorrhizal interactions

    SciTech Connect

    Cseke, Leland

    2016-08-30

    This project addresses the need to develop system-scale models at the symbiotic interface between ectomycorrhizal fungi (Laccaria bicolor) and tree species (Populus tremuloides) in response to environmental nutrient availability / biochemistry. Using our now well-established laboratory Laccaria x poplar system, we address the hypothesis that essential regulatory and metabolic mechanisms can be inferred from genomic, transcriptomic and proteomic-level changes that occur in response to environmental nutrient availability. The project addresses this hypothesis by applying state-of-the-art protein-level analytic approaches to fill the gap in our understanding of how mycorrhizal regulatory and metabolic processes at the transcript-level translate to nutrient uptake, carbon management and ultimate net primary productivity of plants. In most cases, these techniques were not previously optimized for poplar trees or Laccaria. Thus, one of the major contributions of this project has been to provide avenues for new research in these species by overcoming the pitfalls that had previously prevented the use of techniques such as ChIP-Seq and SWATH-proteomics. Since it is the proteins that sense and interact with the environment, participate in signal cascades, activate and regulate gene expression, perform the activities of metabolism and ultimately sequester carbon and generate biomass, an understanding of protein activities during symbiosis-linked nutrient uptake is critical to any systems-level approach that links metabolic processes to the environment. This project uses a team of experts at The University of Alabama in Huntsville (UAH), The University of Alabama at Birmingham (UAB) and Argonne National Laboratory (ANL) to address the above hypothesis using a multiple "omics" approach that combines gene and protein expression as well as protein modifications, and biochemical analyses (performed at Brookhaven National Laboratory (BNL)) in poplar trees under mycorrhizal and

  16. Dissecting nutrient-related co-expression networks in phosphate starved poplars

    PubMed Central

    Kavka, Mareike; Polle, Andrea

    2017-01-01

    Phosphorus (P) is an essential plant nutrient, but its availability is often limited in soil. Here, we studied changes in the transcriptome and in nutrient element concentrations in leaves and roots of poplars (Populus × canescens) in response to P deficiency. P starvation resulted in decreased concentrations of S and major cations (K, Mg, Ca), in increased concentrations of N, Zn and Al, while C, Fe and Mn were only little affected. In roots and leaves >4,000 and >9,000 genes were differently expressed upon P starvation. These genes clustered in eleven co-expression modules of which seven were correlated with distinct elements in the plant tissues. One module (4.7% of all differentially expressed genes) was strongly correlated with changes in the P concentration in the plant. In this module the GO term “response to P starvation” was enriched with phosphoenolpyruvate carboxylase kinases, phosphatases and pyrophosphatases as well as regulatory domains such as SPX, but no phosphate transporters. The P-related module was also enriched in genes of the functional category “galactolipid synthesis”. Galactolipids substitute phospholipids in membranes under P limitation. Two modules, one correlated with C and N and the other with biomass, S and Mg, were connected with the P-related module by co-expression. In these modules GO terms indicating “DNA modification” and “cell division” as well as “defense” and “RNA modification” and “signaling” were enriched; they contained phosphate transporters. Bark storage proteins were among the most strongly upregulated genes in the growth-related module suggesting that N, which could not be used for growth, accumulated in typical storage compounds. In conclusion, weighted gene coexpression network analysis revealed a hierarchical structure of gene clusters, which separated phosphate starvation responses correlated with P tissue concentrations from other gene modules, which most likely represented

  17. Heterologous Overexpression of Poplar SnRK2 Genes Enhanced Salt Stress Tolerance in Arabidopsis thaliana

    PubMed Central

    Song, Xueqing; Yu, Xiang; Hori, Chiaki; Demura, Taku; Ohtani, Misato; Zhuge, Qiang

    2016-01-01

    Subfamily 2 of SNF1-related protein kinase (SnRK2) plays important roles in plant abiotic stress responses as a global positive regulator of abscisic acid signaling. In the genome of the model tree Populus trichocarpa, 12 SnRK2 genes have been identified, and some are upregulated by abiotic stresses. In this study, we heterologously overexpressed the PtSnRK2 genes in Arabidopsis thaliana and found that overexpression of PtSnRK2.5 and PtSnRK2.7 genes enhanced stress tolerance. In the PtSnRK2.5 and PtSnRK2.7 overexpressors, chlorophyll content, and root elongation were maintained under salt stress conditions, leading to higher survival rates under salt stress compared with those in the wild type. Transcriptomic analysis revealed that PtSnRK2.7 overexpression affected stress-related metabolic genes, including lipid metabolism and flavonoid metabolism, even under normal growth conditions. However, the stress response genes reported to be upregulated in Arabidopsis SRK2C/SnRK2.6 and wheat SnRK2.8 overexpressors were not changed by PtSnRK2.7 overexpression. Furthermore, PtSnRK2.7 overexpression widely and largely influenced the transcriptome in response to salt stress; genes related to transport activity, including anion transport-related genes, were characteristically upregulated, and a variety of metabolic genes were specifically downregulated. We also found that the salt stress response genes were greatly upregulated in the PtSnRK2.7 overexpressor. Taken together, poplar subclass 2 PtSnRK2 genes can modulate salt stress tolerance in Arabidopsis, through the activation of cellular signaling pathways in a different manner from that by herbal subclass 2 SnRK2 genes. PMID:27242819

  18. Post-establishment fertilization of Minnesota hybrid poplar plantations.

    SciTech Connect

    Coleman, M., D.; Tolsted, D.; Nichols, T.; Johnson, W., D.; Ween, E.G.; Houghtaling, T.

    2006-01-01

    Experimental plantings were installed at five sites in three locations in western Minnesota. Aboveground biomass production increased 43-82% as a result of three annual applications of urea or balanced nutrient blend fertilizer beginning near canopy closure. There were no production differences between the type of fertilizer used, indicating that N was the major limiting nutrient. Responses were consistent from site to site, indicating that hybrid poplar stands in this region at this stage of development would be very responsive to fertilization. Leaf tissue N, P, and K concentrations increased in response to both fertilizer treatments; P and K increased more frequently in response to the blend treatment compared to the N-only urea treatment. The diagnosis and recommendation integrated system (DRIS) indices indicated that the stands were near optimal nutritional balance prior to fertilization. Treatments increased individual leaf area and leaf litter production up to 33% and 37%, respectively. Canopy leaf area, leaf N concentration and the sum of DRIS indices were correlated with aboveground production. Growth efficiency, the ratio of production to canopy leaf area, increased with both fertilizer treatment and successive years of treatment, indicating improved stand vigor due to nutrient amendments. Stand production increased more in response to changes in leaf N concentration as stands aged. Plantation production continued to increase with increased internal N concentration even when deficiency levels or levels defined as sufficient for fast growth were exceeded. The correlation between aboveground production and the sum of DRIS indices shows that optimal nutrition at canopy closure may result in current aboveground dry matter production exceeding 13Mgha-1 yr-1. Multiple small-dose amendments appear to be effective in increasing production by maintaining high internal N concentrations.

  19. RNA-Seq of Early-Infected Poplar Leaves by the Rust Pathogen Melampsora larici-populina Uncovers PtSultr3;5, a Fungal-Induced Host Sulfate Transporter

    PubMed Central

    Petre, Benjamin; Hacquard, Stéphane; Da Silva, Corinne; Poulain, Julie; Delaruelle, Christine; Martin, Francis; Rouhier, Nicolas; Kohler, Annegret; Duplessis, Sébastien

    2012-01-01

    Biotroph pathogens establish intimate interactions with their hosts that are conditioned by the successful secretion of effectors in infected tissues and subsequent manipulation of host physiology. The identification of early-expressed pathogen effectors and early-modulated host functions is currently a major goal to understand the molecular basis of biotrophy. Here, we report the 454-pyrosequencing transcriptome analysis of early stages of poplar leaf colonization by the rust fungus Melampsora larici-populina. Among the 841,301 reads considered for analysis, 616,879 and 649 were successfully mapped to Populus trichocarpa and M. larici-populina genome sequences, respectively. From a methodological aspect, these results indicate that this single approach is not appropriate to saturate poplar transcriptome and to follow transcript accumulation of the pathogen. We identified 19 pathogen transcripts encoding early-expressed small-secreted proteins representing candidate effectors of interest for forthcoming studies. Poplar RNA-Seq data were validated by oligoarrays and quantitatively analysed, which revealed a highly stable transcriptome with a single transcript encoding a sulfate transporter (herein named PtSultr3;5, POPTR_0006s16150) showing a dramatic increase upon colonization by either virulent or avirulent M. larici-populina strains. Perspectives connecting host sulfate transport and biotrophic lifestyle are discussed. PMID:22952974

  20. Effect of Genetically Modified Poplars on Soil Microbial Communities during the Phytoremediation of Waste Mine Tailings▿†

    PubMed Central

    Hur, Moonsuk; Kim, Yongho; Song, Hae-Ryong; Kim, Jong Min; Choi, Young Im; Yi, Hana

    2011-01-01

    The application of transgenic plants to clean up environmental pollution caused by the wastes of heavy metal mining is a promising method for removing metal pollutants from soils. However, the effect of using genetically modified organisms for phytoremediation is a poorly researched topic in terms of microbial community structures, despite the important role of microorganisms in the health of soil. In this study, a comparative analysis of the bacterial and archaeal communities found in the rhizosphere of genetically modified (GM) versus wild-type (WT) poplar was conducted on trees at different growth stages (i.e., the rhizospheres of 1.5-, 2.5-, and 3-year-old poplars) that were cultivated on contaminated soils together with nonplanted control soil. Based on the results of DNA pyrosequencing, poplar type and growth stages were associated with directional changes in the structure of the microbial community. The rate of change was faster in GM poplars than in WT poplars, but the microbial communities were identical in the 3-year-old poplars. This phenomenon may arise because of a higher rate and greater extent of metal accumulation in GM poplars than in naturally occurring plants, which resulted in greater changes in soil environments and hence the microbial habitat. PMID:21890678

  1. The poplar basic helix-loop-helix transcription factor BEE3 - Like gene affects biomass production by enhancing proliferation of xylem cells in poplar.

    PubMed

    Noh, Seol Ah; Choi, Young-Im; Cho, Jin-Seong; Lee, Hyoshin

    2015-06-19

    Brassinosteroids (BRs) play important roles in many aspects of plant growth and development, including regulation of vascular cambium activities and cell elongation. BR-induced BEE3 (brassinosteroid enhanced expression 3) is required for a proper BR response. Here, we identified a poplar (Populus alba × Populus glandulosa) BEE3-like gene, PagBEE3L, encoding a putative basic helix-loop-helix (bHLH)-type transcription factor. Expression of PagBEE3L was induced by brassinolide (BL). Transcripts of PagBEE3L were mainly detected in stems, with the internode having a low level of transcription and the node having a relatively higher level. The function of the PagBEE3L gene was investigated through phenotypic analyses with PagBEE3L-overexpressing (ox) transgenic lines. This work particularly focused on a potential role of PagBEE3L in stem growth and development of polar. The PagBEE3L-ox poplar showed thicker and longer stems than wild-type plants. The xylem cells from the stems of PagBEE3L-ox plants revealed remarkably enhanced proliferation, resulting in an earlier thickening growth than wild-type plants. Therefore, this work suggests that xylem development of poplar is accelerated in PagBEE3L-ox plants and PagBEE3L plays a role in stem growth by increasing the proliferation of xylem cells to promote the initial thickening growth of poplar stems.

  2. Poplar clones of different sizes, grown on a heavy metal polluted site, are associated with microbial populations of varying composition.

    PubMed

    Gamalero, Elisa; Cesaro, Patrizia; Cicatelli, Angela; Todeschini, Valeria; Musso, Chiara; Castiglione, Stefano; Fabiani, Arturo; Lingua, Guido

    2012-05-15

    We performed a field trial to evaluate the response of different poplar clones to heavy metals. We found that poplar plants of the same clone, propagated by cuttings, had a marked variability of survival and growth in different zones of the field that were characterized by very similar physical-chemical prosperities. Since metal uptake and its accumulation by plants can be affected by soil microorganisms, we investigated soil microbial populations that were collected in proximity to the roots of large and small poplar plants. We used microbiological and molecular tools to ascertain whether bacterial strains or species were associated with large, or small poplars, and whether these were different from those present in the bulk (without plants) soil. We found that the culturable fraction of the bacteria differed in the three cases (bulk soil, small or large poplars). While some taxa were always present, two species (Chryseobacterium soldanellicola and Variovorax paradoxus) were only found in the soil where poplars (large or small) were growing, independently from the plant size. Bacterial strains of the genus Flavobacterium were prevalent in the soil with large poplar plants. The existence of different microbial populations in the bulk and in the poplar grown soils was confirmed by the DGGE profiles of the bacterial culturable fractions. Cluster analysis of the DGGE profiles highlighted the clear separation of the culturable fraction from the whole microbial community. The isolation and identification of poplar-associated bacterial strains from the culturable fraction of the microbial community provided the basis for further studies aimed at the combined use of plants and soil microorganisms in the remediation of heavy metal polluted soils.

  3. Response to drought and salt stress in leaves of poplar (Populus alba × Populus glandulosa): expression profiling by oligonucleotide microarray analysis.

    PubMed

    Yoon, Seo-Kyung; Park, Eung-Jun; Choi, Young-Im; Bae, Eun-Kyung; Kim, Joon-Hyeok; Park, So-Young; Kang, Kyu-Suk; Lee, Hyoshin

    2014-11-01

    Drought and salt stresses are major environmental constraints on forest productivity. To identify genes responsible for stress tolerance, we conducted a genome-wide analysis in poplar (Populus alba × Populus glandulosa) leaves exposed to drought and salt (NaCl) stresses. We investigated gene expression at the mRNA level using oligonucleotide microarrays containing 44,718 genes from Populus trichocarpa. A total of 1604 and 1042 genes were up-regulated (≥2-fold; P value < 0.05) by drought and salt stresses, respectively, and 765 genes were up-regulated by both stresses. In addition, 2742 and 1685 genes were down-regulated by drought and salt stresses, respectively, and 1564 genes were down-regulated by both stresses. The large number of genes regulated by both stresses suggests that crosstalk occurs between the drought and salt stress responses. Most up-regulated genes were involved in functions such as subcellular localization, signal transduction, metabolism, and transcription. Among the up-regulated genes, we identified 47 signaling proteins, 65 transcription factors, and 43 abiotic stress-related genes. Several genes were modulated by only one of the two stresses. About 25% of the genes significantly regulated by these stresses are of unknown function, suggesting that poplar may provide an opportunity to discover novel stress-related genes.

  4. Final Report: Exudation by Poplar Ectomycorrhizas: Qualitative and Quantitative Assessment of C Sequestration

    SciTech Connect

    Cumming, J R

    2012-11-12

    Study 1. We compared mycorrhizal Populus tremuloides inoculated with Laccaria bicolor and nonmycorrhizal (NM) P. tremuloides seedlings grown under different levels of P nutrition. Decreasing concentrations of P significantly increased the activity of reactive oxygen scavenging enzymes. In addition, phosphoenolpyruvate carboxylase activity increased under P limitation. P deficiency also increased organic acid exudation and total organic carbon exudation. Colonization by L. bicolor reduced the P concentration thresholds where these physiological changes occurred. Study 2. We assessed the influences of ectomycorrhizal colonization on phosphate limitation responses of trembling aspen. Photosynthetic CO2 uptake was reduced in NM poplar, but not in plants colonized by L. bicolor or P. involutus. Reductions in shoot and root biomass in NM plants were substantially greater than reductions in plants colonized by either ectomycorrhizal fungi. Leaf starch and sugar concentrations declined with Pi limitation across mycorrhizal treatments, but were higher in plants colonized by L. bicolor and P. involutus. In roots, starch concentrations were greater in NM plants with Pi limitation. In roots, sugars were significantly higher in NM plants compared to mycorrhizal plants and increased significantly in NM plants under Pi limitation. Concentrations were unaffected by Pi limitation in plants colonized by L. bicolor or P. involutus. Study 3. We analyzed proteins that were differentially expressed during the mycorrhizal association. A comparison of global protein expression elucidated broad differences in protein profiles between NM plants and plants colonized by ectomycorrhizal (ECM) or arbuscular mycorrhizal (AM) fungi as well as differences between the ECM fungi L. bicolor and P. involutus. Plants colonized by P. involutus and G. intraradices exhibited unique patterns of up/down-regulated proteins compared to NM plants, whereas plants colonized by L. bicolor exhibited patterns of

  5. Storm water control plan for the Lower East Fork Poplar Creek Operable Unit, Oak Ridge, Tennessee

    SciTech Connect

    1996-04-01

    This document provides the Environmental Restoration Program with information about the erosion and sediment control, storm water management, maintenance, and reporting and record keeping practices to be employed during Phase II of the remediation project for the Lower East Fork Poplar Creek (LEFPC) Operable Unit.

  6. Metabolic Responses of Poplar to Apripona germari (Hope) as Revealed by Metabolite Profiling

    PubMed Central

    Wang, Lijuan; Qu, Liangjian; Zhang, Liwei; Hu, Jianjun; Tang, Fang; Lu, Mengzhu

    2016-01-01

    Plants have developed biochemical responses to adapt to biotic stress. To characterize the resistance mechanisms in poplar tree against Apripona germari, comprehensive metabolomic changes of poplar bark and xylem in response to A. germari infection were examined by gas chromatography time-of-flight mass spectrometry (GC–TOF/MS). It was found that, four days after feeding (stage I), A. germari infection brought about changes in various metabolites, such as phenolics, amino acids and sugars in both bark and xylem. Quinic acid, epicatechin, epigallocatechin and salicin might play a role in resistance response in bark, while coniferyl alcohol, ferulic acid and salicin contribute resistance in xylem. At feeding stages II when the larvae fed for more than one month, fewer defensive metabolites were induced, but levels of many intermediates of glycolysis and the tricarboxylic acid (TCA) cycle were reduced, especially in xylem. These results suggested that the defense strategies against A. germari might depend mainly on the early defense responses in poplar. In addition, it was found that bark and xylem in infected trees accumulated higher levels of salicylic acid and 4-aminobutyric acid, respectively, these tissues displaying a direct and systemic reaction against A. germari. However, the actual role of the two metabolites in A. germari-induced defense in poplar requires further investigation. PMID:27331808

  7. Exploring the role of asexual multiplication in poplar rust epidemics: impact on diversity and genetic structure.

    PubMed

    Barrès, Benoît; Dutech, Cyril; Andrieux, Axelle; Halkett, Fabien; Frey, Pascal

    2012-10-01

    Fungal plant pathogens, especially rust fungi (Pucciniales), are well known for their complex life cycles, which include phases of sexual and asexual reproduction. The effect of asexual multiplication on population genetic diversity has been investigated in the poplar rust fungus Melampsora larici-populina using a nested hierarchical sampling scheme. Four hierarchical levels were considered: leaf, twig, tree and site. Both cultivated and wild poplar stands were sampled at two time points at the start and end of rust epidemics. A total of 641 fungal isolates was analysed using nine microsatellite markers. This study revealed that the genetic signature of asexual multiplication in the wild poplar stand was seen only at lower hierarchical levels (leaf and twig). Moreover, we observed an erosion of clonal structure through time, with an increase in both gene and genotypic diversity. New genotypes contributed to host infection over time, which demonstrates the importance of allo-infection in the epidemic process in this host-pathogen system. Compared with the wild stands, the nearly lack of detection of clonal structure in the cultivated stands reflects the higher infection level on cultivated poplars. More generally, this genetic analysis illustrates the utility of population genetics approach for elucidating the proportion of asexual reproduction in the multiplication of isolates during an epidemic, and for proper quantification of asexual dispersal in plant pathogens.

  8. Poplar PtabZIP1-like enhances lateral root formation and biomass growth under drought stress.

    PubMed

    Dash, Madhumita; Yordanov, Yordan S; Georgieva, Tatyana; Tschaplinski, Timothy J; Yordanova, Elena; Busov, Victor

    2017-02-01

    Developing drought-resistance varieties is a major goal for bioenergy crops, such as poplar (Populus), which will be grown on marginal lands with little or no water input. Root architecture can affect drought resistance, but few genes that affect root architecture in relation to water availability have been identified. Here, using activation tagging in the prime bioenergy crop poplar, we have identified a mutant that overcomes the block of lateral root (LR) formation under osmotic stress. Positioning of the tag, validation of the activation and recapitulation showed that the phenotype is caused by the poplar PtabZIP1-like (PtabZIP1L) gene with highest homology to bZIP1 from Arabidopsis. PtabZIP1L is predominantly expressed in roots, particularly in zones where lateral root primordia (LRP) initiate and LR differentiate and emerge. Transgenics overexpressing PtabZIP1L showed precocious LRP and LR development, while PtabZIP1L suppression significantly delayed both LRP and LR formation. Transgenic overexpression and suppression of PtabZIP1L also resulted in modulation of key metabolites like proline, asparagine, valine and several flavonoids. Consistently, expression of both of the poplar Proline Dehydrogenase orthologs and two of the Flavonol Synthases genes was also increased and decreased in overexpressed and suppressed transgenics, respectively. These findings suggest that PtabZIP1L mediates LR development and drought resistance through modulation of multiple metabolic pathways.

  9. Soil respiration in apple orchards, poplar plantations and adjacent grasslands in Artvin, Turkey.

    PubMed

    Tufekcioglu, Aydin; Ozbayram, Ali Kemal; Kucuk, Mehmet

    2009-09-01

    In this study influence of land-use type on soil respiration was investigated in poplar plantation, apple orchard (apple trees with understory grasses) and adjacent grassland sites in Seyitler Area, Artvin, Turkey. Soil respiration was measured approximately monthly in three sampling plots in each land use type from January 2005 to November 2005 using the soda-lime technique. Mean daily soil respiration ranged from 0.63-3.59 g Cm(-2) d(-1). Mean soil respiration in apple orchard, poplar plantation and grassland sites were 1.98, 1.45 and 1.12 g C m(-2) d(-1), respectively. Mean soil respiration was significantly greater in apple orchard than in poplar plantations and grasslands. Seasonal changes in soil respiration were related to soil moisture and temperature changes. Mean soil respiration rate correlated strongly with subsurface soil (15-35cm) pH (R = -0,73; p < 0.05), sand content (R = 0.96, p < 0.001), soil silt content (R = -0.75; p < 0.05), soil clay content (R = -0.83; p < 0.001) and organic matter content (R = 0.88; p < 0.001). No significant correlations were observed between soil respiration and surface (0-15 cm) soil properties and root biomass. Overall, our results indicate that apple orchards with understory grasses have higher soil biological activity compared to poplar and grassland sites.

  10. Lignin engineering in field-grown poplar trees affects the endosphere bacterial microbiome

    PubMed Central

    Beckers, Bram; Op De Beeck, Michiel; Weyens, Nele; Van Acker, Rebecca; Van Montagu, Marc; Boerjan, Wout; Vangronsveld, Jaco

    2016-01-01

    Cinnamoyl-CoA reductase (CCR), an enzyme central to the lignin biosynthetic pathway, represents a promising biotechnological target to reduce lignin levels and to improve the commercial viability of lignocellulosic biomass. However, silencing of the CCR gene results in considerable flux changes of the general and monolignol-specific lignin pathways, ultimately leading to the accumulation of various extractable phenolic compounds in the xylem. Here, we evaluated host genotype-dependent effects of field-grown, CCR-down-regulated poplar trees (Populus tremula × Populus alba) on the bacterial rhizosphere microbiome and the endosphere microbiome, namely the microbiota present in roots, stems, and leaves. Plant-associated bacteria were isolated from all plant compartments by selective isolation and enrichment techniques with specific phenolic carbon sources (such as ferulic acid) that are up-regulated in CCR-deficient poplar trees. The bacterial microbiomes present in the endosphere were highly responsive to the CCR-deficient poplar genotype with remarkably different metabolic capacities and associated community structures compared with the WT trees. In contrast, the rhizosphere microbiome of CCR-deficient and WT poplar trees featured highly overlapping bacterial community structures and metabolic capacities. We demonstrate the host genotype modulation of the plant microbiome by minute genetic variations in the plant genome. Hence, these interactions need to be taken into consideration to understand the full consequences of plant metabolic pathway engineering and its relation with the environment and the intended genetic improvement. PMID:26755604

  11. Gaseous NO2 effects on stomatal behavior, photosynthesis and respiration of hybrid poplar leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, we used poplar as a model plant and investigated the effects of gaseous nitrogen dioxide (NO2, 4 microliter per liter) on stomatal conductance, photosynthesis, dark- and photorespiration of Populus alba x Populus berolinensis hybrid leaves using the photosynthesis system and scanning...

  12. Nucleotide diversity among natural populations of a North American poplar (Populus balsamifera, Salicaceae).

    PubMed

    Breen, Amy L; Glenn, Elise; Yeager, Adam; Olson, Matthew S

    2009-01-01

    Poplars (Populus spp.) comprise an important component of circumpolar boreal forest ecosystems and are the model species for tree genomics. In this study, we surveyed genetic variation and population differentiation in three nuclear genes among populations of balsam poplar (Populus balsamifera) in North America. We examined nucleotide sequence variation in alcohol dehydrogenase 1 (Adh1) and glyceraldehyde 3-phosphate dehydrogenase (G3pdh), two well-studied nuclear loci in plants, and abscisic acid insensitivity 1B (ABI1B), a locus coincident with timing of seasonal dormancy in quantitative trait locus (QTL) studies of hybrid poplars. We compared estimates of baseline population genetic parameters for these loci with those obtained in studies of other poplar species, particularly European aspen (Populus tremula). Average pairwise nucleotide diversity (pi(tot) = 0.00216-0.00353) was equivalent to that in Populus trichocarpa, but markedly less than that in P. tremula. Elevated levels of population structure were observed in ABI1B between the northern and southern regions (F(CT) = 0.184, P < 0.001) and among populations (F(ST) = 0.256, P < 0.001). These results suggest that geographic or taxonomic factors are important for understanding patterns of variation throughout the genus Populus. Our findings have the potential to aid in the design of sampling regimes for conservation and breeding stock and contribute to historical inferences regarding the factors that shaped the genetic diversity of boreal plant species.

  13. Poplar PtabZIP1-like enhances lateral root formation and biomass growth under drought stress

    DOE PAGES

    Dash, Madhumita; Yordanov, Yordan S.; Georgieva, Tatyana; ...

    2017-02-10

    Developing drought-resistance varieties is a major goal for bioenergy crops, such as poplar (Populus), which will be grown on marginal lands with little or no water input. Root architecture can affect drought resistance, but few genes that affect root architecture in relation to water availability have been identified. Here in this study, using activation tagging in the prime bioenergy crop poplar, we have identified a mutant that overcomes the block of lateral root (LR) formation under osmotic stress. Positioning of the tag, validation of the activation and recapitulation showed that the phenotype is caused by the poplar PtabZIP1-like (PtabZIP1L) genemore » with highest homology to bZIP1 from Arabidopsis. PtabZIP1L is predominantly expressed in roots, particularly in zones where lateral root primordia (LRP) initiate and LR differentiate and emerge. Transgenics overexpressing PtabZIP1L showed precocious LRP and LR development, while PtabZIP1L suppression significantly delayed both LRP and LR formation. Transgenic overexpression and suppression of PtabZIP1L also resulted in modulation of key metabolites like proline, asparagine, valine and several flavonoids. Consistently, expression of both of the poplar Proline Dehydrogenase orthologs and two of the Flavonol Synthases genes was also increased and decreased in overexpressed and suppressed transgenics, respectively. These findings suggest that PtabZIP1L mediates LR development and drought resistance through modulation of multiple metabolic pathways.« less

  14. Production of Hybrid Poplar under Short-Term, Intensive Culture in Western Colorado

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An irrigated study was conducted at the Western Colorado Research Center at Fruita for 6 yr to evaluate eight hybrid poplar clones under short-term, intensive culture. The eight clones included in the study were Populus nigra x P. maximowiczii (NM6), P. trichocarpa x P. deltoides (52225, OP367), and...

  15. Lignin engineering in field-grown poplar trees affects the endosphere bacterial microbiome.

    PubMed

    Beckers, Bram; Op De Beeck, Michiel; Weyens, Nele; Van Acker, Rebecca; Van Montagu, Marc; Boerjan, Wout; Vangronsveld, Jaco

    2016-02-23

    Cinnamoyl-CoA reductase (CCR), an enzyme central to the lignin biosynthetic pathway, represents a promising biotechnological target to reduce lignin levels and to improve the commercial viability of lignocellulosic biomass. However, silencing of the CCR gene results in considerable flux changes of the general and monolignol-specific lignin pathways, ultimately leading to the accumulation of various extractable phenolic compounds in the xylem. Here, we evaluated host genotype-dependent effects of field-grown, CCR-down-regulated poplar trees (Populus tremula × Populus alba) on the bacterial rhizosphere microbiome and the endosphere microbiome, namely the microbiota present in roots, stems, and leaves. Plant-associated bacteria were isolated from all plant compartments by selective isolation and enrichment techniques with specific phenolic carbon sources (such as ferulic acid) that are up-regulated in CCR-deficient poplar trees. The bacterial microbiomes present in the endosphere were highly responsive to the CCR-deficient poplar genotype with remarkably different metabolic capacities and associated community structures compared with the WT trees. In contrast, the rhizosphere microbiome of CCR-deficient and WT poplar trees featured highly overlapping bacterial community structures and metabolic capacities. We demonstrate the host genotype modulation of the plant microbiome by minute genetic variations in the plant genome. Hence, these interactions need to be taken into consideration to understand the full consequences of plant metabolic pathway engineering and its relation with the environment and the intended genetic improvement.

  16. Removal of boron from wastewater: Evaluation of seven poplar clones for B accumulation and tolerance.

    PubMed

    Chen, Zhifan; Taylor, Alicia A; Astor, Savina R; Xin, Junliang; Terry, Norman

    2017-01-01

    Boron (B) contamination of wastewater is a serious environmental and health problem, which has proved difficult to remediate. One potential approach is phytoremediation, i.e., the use of plants to extract B into the shoot systems, which can then be harvested and removed. The purpose of this study was to investigate the ability of seven hybrid poplar clones to accumulate and tolerate B at different levels of B and salinity. The clones were grown in quarter strength Hoagland's nutrient solution and exposed to four B treatments: 0.25, 25, 75 and 125 mg B L(-1) in factorial combination with three salinity treatments: 0, 0.5 and 5 g L(-1). Measurements were made of biomass (dry weight) and B concentrations (analyzed by inductively coupled plasma-optical emission spectroscopy) of plant tissues. The results showed that, with increasing level of B supply, the B concentrations in the shoot tissue of the poplar clones increased, while shoot biomass decreased. Comparison of the seven different poplar clones revealed that the clone designated 195-529 exhibited the greatest ability for B accumulation and tolerance. Generally, the 0.5 g L(-1) level of salinity was beneficial for poplar growth and B removal, while the high salinity level of 5 g L(-1) significantly inhibited poplar growth and B translocation from roots to shoots. Based on the results obtained with this hydroponic system, the clone 195-529 (P. trichocarpa × P. deltoides) is likely to be the most useful for the removal of B from B contaminated wastewater.

  17. Forest biorefinery: Potential of poplar phytochemicals as value-added co-products.

    PubMed

    Devappa, Rakshit K; Rakshit, Sudip K; Dekker, Robert F H

    2015-11-01

    The global forestry industry after experiencing a market downturn during the past decade has now aimed its vision towards the integrated biorefinery. New business models and strategies are constantly being explored to re-invent the global wood and pulp/paper industry through sustainable resource exploitation. The goal is to produce diversified, innovative and revenue generating product lines using on-site bioresources (wood and tree residues). The most popular product lines are generally produced from wood fibers (biofuels, pulp/paper, biomaterials, and bio/chemicals). However, the bark and other tree residues like foliage that constitute forest wastes, still remain largely an underexploited resource from which extractives and phytochemicals can be harnessed as by-products (biopharmaceuticals, food additives and nutraceuticals, biopesticides, cosmetics). Commercially, Populus (poplar) tree species including hybrid varieties are cultivated as a fast growing bioenergy crop, but can also be utilized to produce bio-based chemicals. This review identifies and underlines the potential of natural products (phytochemicals) from Populus species that could lead to new business ventures in biorefineries and contribute to the bioeconomy. In brief, this review highlights the importance of by-products/co-products in forest industries, methods that can be employed to extract and purify poplar phytochemicals, the potential pharmaceutical and other uses of >160 phytochemicals identified from poplar species - their chemical structures, properties and bioactivities, the challenges and limitations of utilizing poplar phytochemicals, and potential commercial opportunities. Finally, the overall discussion and conclusion are made considering the recent biotechnological advances in phytochemical research to indicate the areas for future commercial applications from poplar tree species.

  18. Isoprene in poplar emissions: effects on new particle formation and OH concentrations

    NASA Astrophysics Data System (ADS)

    Kiendler-Scharr, A.; Andres, S.; Bachner, M.; Behnke, K.; Broch, S.; Hofzumahaus, A.; Holland, F.; Kleist, E.; Mentel, T. F.; Rubach, F.; Springer, M.; Steitz, B.; Tillmann, R.; Wahner, A.; Schnitzler, J.-P.; Wildt, J.

    2011-08-01

    Stress-induced volatile organic compound (VOC) emissions from transgenic Grey poplar, modified in isoprene emission potential were used for the investigation of photochemical secondary organic aerosol (SOA) formation. Nucleation rates of up to 3600 cm-3 s-1 were observed in our experiments. In poplar, acute ozone stress induces the emission of a wide array of VOCs dominated by sesquiterpenes and aromatic VOCs. Constitutive light-dependent emission of isoprene ranged between 66 nmol m-2 s-1 in non-transgenic controls (wild type WT) and nearly zero (<0.5 nmol m-2 s-1) in isoprene emission-repressed lines (line RA22), respectively. In the presence of isoprene new particle formation was suppressed compared to non-isoprene containing VOC mixtures. Compared to isoprene/monoterpene systems emitted from other plants the suppression of nucleation by isoprene was less effective for the VOC mixture emitted from stressed poplar. This is explained by the observed high efficiency of new particle formation for emissions from stressed poplar. Direct measurements of OH in the reaction chamber revealed that the steady state concentration of OH is lower in the presence of isoprene than in the absence of isoprene, supporting the hypothesis that isoprenes' suppressing effect on nucleation is related to radical chemistry. In order to test whether isoprene contributes to SOA mass formation, fully deuterated isoprene (C5D8) was added to the stress-induced emission profile of an isoprene free poplar mutant. Mass spectral analysis showed that, despite the isoprene-induced suppression of particle formation, fractions of deuterated isoprene were incorporated into the SOA. A fractional mass yield of 2.3 % of isoprene was observed. Future emission changes due to land use and climate change may therefore affect both gas phase oxidation capacity and new particle number formation.

  19. Isoprene in poplar emissions: effects on new particle formation and OH concentrations

    NASA Astrophysics Data System (ADS)

    Kiendler-Scharr, A.; Andres, S.; Bachner, M.; Behnke, K.; Broch, S.; Hofzumahaus, A.; Holland, F.; Kleist, E.; Mentel, T. F.; Rubach, F.; Springer, M.; Steitz, B.; Tillmann, R.; Wahner, A.; Schnitzler, J.-P.; Wildt, J.

    2012-01-01

    Stress-induced volatile organic compound (VOC) emissions from transgenic Grey poplar modified in isoprene emission potential were used for the investigation of photochemical secondary organic aerosol (SOA) formation. In poplar, acute ozone stress induces the emission of a wide array of VOCs dominated by sesquiterpenes and aromatic VOCs. Constitutive light-dependent emission of isoprene ranged between 66 nmol m-2 s-1 in non-transgenic controls (wild type WT) and nearly zero (<0.5 nmol m-2 s-1) in isoprene emission-repressed plants (line RA22), respectively. Nucleation rates of up to 3600 cm-3 s-1 were observed in our experiments. In the presence of isoprene new particle formation was suppressed compared to non-isoprene containing VOC mixtures. Compared to isoprene/monoterpene systems emitted from other plants the suppression of nucleation by isoprene was less effective for the VOC mixture emitted from stressed poplar. This is explained by the observed high efficiency of new particle formation for emissions from stressed poplar. Direct measurements of OH in the reaction chamber revealed that the steady state concentration of OH is lower in the presence of isoprene than in the absence of isoprene, supporting the hypothesis that isoprenes' suppressing effect on nucleation is related to radical chemistry. In order to test whether isoprene contributes to SOA mass formation, fully deuterated isoprene (C5D8) was added to the stress-induced emission profile of an isoprene free poplar mutant. Mass spectral analysis showed that, despite the isoprene-induced suppression of particle formation, fractions of deuterated isoprene were incorporated into the SOA. A fractional mass yield of 2.3% of isoprene was observed. Future emission changes due to land use and climate change may therefore affect both gas phase oxidation capacity and new particle number formation.

  20. [Effects of the decomposition of poplar and alder mixed leaf litters on soil microbial biomass].

    PubMed

    Chen, Qin; Fang, Sheng-Zuo; Tian, Ye

    2012-08-01

    An incubation test was conducted to study the effects of the decomposition of poplar and trabeculate alder leaf litters with different mixed ratios and under different application ways on soil microbial biomass carbon (MBC) and nitrogen (MBN). The mixed ratio of the litters had significant effects on soil MBC and MBN. On the 30th day of incubation, soil MBC and MBN were significantly higher in the treatments with > or = 50% of alder litter than in the treatment with poplar litter only and the control. On the 75th day of incubation, the soil MBC in the treatments with > or = 40% of alder litter and the soil MBN in the treatments with > or = 30% of alder litter were significantly greater than those in the treatment with poplar litter only and the control. After 135 days incubation, soil MBC and MBN were significant higher in the treatments with > or = 20% and > or = 40% of alder litter than in the treatment with poplar litter only and the control, respectively. There was no significant difference in the soil MBC/MBN between the treatments with different mixed ratios of poplar and alder leaf litters and the control. Overall, soil MBC/MBN increased during the early period of incubation and decreased in the later period, suggesting that soil microflora changed during the decomposition of the litters. In the whole incubation period, the application ways of the litters had lesser effects on the soil MBC, MBN, and MBC/MBN, indicating that the addition ways of the litters did not affect soil microflora.

  1. Photosynthesis and substrate supply for isoprene biosynthesis in poplar leaves

    NASA Astrophysics Data System (ADS)

    Magel, E.; Mayrhofer, S.; Müller, A.; Zimmer, I.; Hampp, R.; Schnitzler, J.-P.

    Gray poplar leaves emit high amounts of isoprene. In this context, we investigated the degree to which photosynthesis delivers necessary precursors for chloroplast isoprene biosynthesis, and whether this energy-consuming pathway could be involved in protecting the photosynthetic electron transport system. Such protection could result from consumption of a surplus in ATP and NADPH, generated under constricted net assimilation caused by high leaf temperatures and high light intensities. During the course of the day triose phosphate (TP) and dimethylallyl diphosphate (DMADP) concentrations showed pronounced diurnal variations closely related to net assimilation and isoprene emission rates, while other variables, e.g. energy (ATP/ADP) and redox (NADPH/NADP) ratio, as well as phosphoenolpyruvate (PEP) and pyruvate strongly scattered related to changing temperature and light intensities. Intra-day positive correlations were found mainly between leaf concentrations of TP and DMADP, and sucrose, ATP/ADP ratio and net assimilation rates. Under non-saturating light (200-400 μmol photons m -2 s -1), leaf DMADP pools were positively correlated mainly with PEP, starch, and fructose 2,6-bisphosphate (F26BP). Under saturating light, correlations improved and additionally involved sucrose, TP, and the ratio of NADPH/NADP. Study of temperature response curves showed that net assimilation and isoprene emission were negatively correlated to each other. This disconnection was mostly visible by the transient change of DMADP contents with maximum levels at 25 °C. At higher temperatures, declining pools of DMADP, TP and pyruvate indicated that DMADP consumption overcompensated DMADP production resulting in highest isoprene emission rates at declining pool sizes of precursors. In parallel to the reduction of net assimilation increases of NADPH/NADP and ATP/ADP ratios also portended that the MEP pathway dissipates a surplus of ATP and NADPH which cannot be used for carbon reduction under

  2. Poplar breeding and testing strategies in the NC US: Demonstration of potential yield and consideration of future research needs.

    SciTech Connect

    Riemenschneider, Don; Berguson, William E; Dickmann, Don; Hall, Richard

    2004-06-30

    The objective of this project was to extend previous poplar breeding and selection in the NC US by implementing a regional testing system with multiple test locations in Minnesota, Iowa, Wisconsin and Michigan.

  3. Predicting yields of short-rotation hybrid poplar (Populus spp.) for the United States through model-data synthesis.

    PubMed

    Wang, Dan; LeBauer, David; Dietze, Michael

    2013-06-01

    Hybrid poplar (Populus spp.) is an important biomass crop being evaluated for cellulosic ethanol production. Predictions of poplar growth, rotation period, and soil carbon sequestration under various growing conditions, soils, and climates are critical for farmers and managers planning to establish short-rotation forestry (SRF) plantations. In this study, we used an ecoinformatics workflow, the Predictive Ecosystem Analyzer (PEcAn), to integrate literature data and field measurements into the Ecosystem Demography 2 (ED2) model to estimate yield potential of poplar plantations. Within PEcAn 164 records of seven different traits from the literature were assimilated using a Bayesian meta-analysis. Next, variance decomposition identified seven variables for further constraint that contributed > 80% to the uncertainty in modeled yields: growth respiration, dark respiration, quantum efficiency, mortality coefficient, water conductance, fine-root allocation, and root turnover rate. Assimilation of observed yields further constrained uncertainty in model parameters (especially dark respiration and root turnover rate) and biomass estimates. Additional measurements of growth respiration, mortality, water conductance, and quantum efficiency would provide the most efficient path toward further constraint of modeled yields. Modeled validation demonstrated that ED2 successfully captured the interannual and spatial variability of poplar yield observed at nine independent sites. Site-level analyses were conducted to estimate the effect of land use change to SRF poplar on soil C sequestration compared to alternate land uses. These suggest that poplar plantations became a C sink within 18 years of conversion from corn production or existing forest. Finally, poplar yields were estimated for the contiguous United States at a half degree resolution in order to determine potential productivity, estimate the optimal rotation period, and compare poplar to perennial grass yields. This

  4. Co-liquefaction of the Elbistan Lignite and Poplar Sawdust. Part I: The Effect of the Liquefaction Parameters

    SciTech Connect

    Karaca, H.; Acar, M.; Yilmaz, M.; Keklik, I.

    2009-07-01

    In this study, the liquefaction of Elbistan lignite and poplar sawdust, and the co-liquefaction of the Elbistan lignite and the poplar sawdust in an inert atmosphere and in non-catalytic conditions have been examined. Also, the effects of solvent/coal ratio and stirring speed on the total conversion derived as the result of the liquefaction process was attempted to be determined. Based on the results, although the effects of the solvent/coal ratio and the stirring speed on total conversion are similar for both the Elbistan lignite and the poplar sawdust, it was also noted that, under similar conditions, the conversion for the poplar sawdust was higher, as compared to the conversion of the Elbistan lignite. As the result of the liquefaction of Elbistan lignite and poplar sawdust under inert atmospheric conditions, the total conversion was increased partially, depending on both solvent/coal ratio and the speed of stirring. However, it was also noted that the total conversion did not change to a significant extent in high solvent/coal ratios and in stirring speed. As the result of the co-liquefaction of the Elbistan lignite and poplar sawdust under inert atmospheric conditions, total conversion was increased, based on the solvent/coal ratio. However, as in the case of the liquefaction of Elbistan lignite and poplar sawdust, it was noted that the high solvent/coal ratios (i.e., solvent/coal ratios of higher than 2/1) did not have a significant effect on the total conversion that was derived as the result of the co-liquefaction of the Elbistan lignite and poplar sawdust.

  5. Constitutive expression of the Poplar FD-like basic leucine zipper transcription factor alters growth and bud development.

    PubMed

    Parmentier-Line, Cécile M; Coleman, Gary D

    2016-01-01

    In poplar, the CO/FT regulatory module mediates seasonal growth cessation. Although FT interacts with the basic leucine zipper transcription factor FD, surprisingly little is known about the possible role of FD in bud development and growth cessation in trees. In this study, we examined the expression and localization of the poplar FD homolog, PtFD1, during short-day (SD)-induced bud development, and the consequences of overexpressing PtFD1 on bud development and shoot growth. PtFD1 was primarily expressed in apical and axillary buds and exhibited a transient increase in expression during the initial stages of SD-induced bud development. This transient increase declined with continued SD treatment. When PtFD1 was overexpressed in poplar, SD-induced growth cessation and bud formation were abolished. PTFD1 overexpression also resulted in precocious flowering of juvenile plants in long-day (LD) photoperiods. Because the phenotypes associated with overexpression of PtFD1 are similar to those observe when poplar FT1 is overexpressed (Science, 312, 2006, 1040), the expression and diurnal patterns of expression of both poplar FT1 and FT2 were characterized in PtFD1 overexpression poplars and found to be altered. DNA microarray analysis revealed few differences in gene expression between PtFD1 overexpressing poplars in LD conditions while extensive levels of differential gene expression occur in SD-treated plants. These results enforce the connection between the regulation of flowering and the regulation of growth cessation and bud development in poplar.

  6. Stimulation of hybrid poplar growth in petroleum-contaminated soils through oxygen addition and soil nutrient amendments.

    PubMed

    Rentz, Jeremy A; Chapman, Brad; Alvarez, Pedro J J; Schnoor, Jerald L

    2003-01-01

    Hybrid poplar trees (Populus deltoides x nigra DN34) were grown in a green-house using hydrocarbon-contaminated soil from a phytoremediation demonstration site in Health, Ohio. Two independent experiments investigated the effect of nutrient addition on poplar growth and the importance of oxygen addition to root development and plant growth. Biomass measurements, poplar height, and leaf color were used as indicators of plant health in the selection of a 10/5/5 NPK fertilizer applied at 1121 kg/ha (112 kg-N, 24.4 kg-P, 46.5 kg-K per ha) to enhance hybrid poplar growth at the Health site. Five passive methods of oxygen delivery were examined, including aeration tubes, gravel addition, and an Oxygen Release Compound (ORC). When ORC was placed in coffee filters above hydrocarbon-contaminated soil, a statistically significant increase of 145% was observed in poplar biomass growth, relative to unamended controls. The ORC in filters also stimulated significant increases in root density. A 15.2-cm interval of soil directly below ORC addition exhibited an increase from 2.6 +/- 1.0 mg/cm3 to 4.8 +/- 1.0 mg/cm3, showing stimulation of root growth in hydrocarbon-stained soil. The positive response of hybrid poplars to oxygen amendments suggests that overcoming oxygen limitation to plants should be considered in phytoremediation projects when soil contamination exerts a high biochemical oxygen demand, such as in former refinery sites.

  7. Interaction between isoprene and ozone fluxes in a poplar plantation and its impact on air quality at the European level

    NASA Astrophysics Data System (ADS)

    Zenone, Terenzio; Hendriks, Carlijn; Brilli, Federico; Fransen, Erik; Gioli, Beniamio; Portillo-Estrada, Miguel; Schaap, Martijn; Ceulemans, Reinhart

    2016-09-01

    The emission of isoprene and other biogenic volatile organic compounds from vegetation plays an important role in tropospheric ozone (O3) formation. The potentially large expansion of isoprene emitting species (e.g., poplars) for bioenergy production might, therefore, impact tropospheric O3 formation. Using the eddy covariance technique we have simultaneously measured fluxes isoprene, O3 and of CO2 from a poplar (Populus) plantation grown for bioenergy production. We used the chemistry transport model LOTOS-EUROS to scale-up the isoprene emissions associated with the existing poplar plantations in Europe, and we assessed the impact of isoprene fluxes on ground level O3 concentrations. Our findings suggest that isoprene emissions from existing poplar-for-bioenergy plantations do not significantly affect the ground level of O3 concentration. Indeed the overall land in Europe covered with poplar plantations has not significantly changed over the last two decades despite policy incentives to produce bioenergy crops. The current surface area of isoprene emitting poplars-for-bioenergy remains too limited to significantly enhance O3 concentrations and thus to be considered a potential threat for air quality and human health.

  8. Interaction between isoprene and ozone fluxes in a poplar plantation and its impact on air quality at the European level

    PubMed Central

    Zenone, Terenzio; Hendriks, Carlijn; Brilli, Federico; Fransen, Erik; Gioli, Beniamio; Portillo-Estrada, Miguel; Schaap, Martijn; Ceulemans, Reinhart

    2016-01-01

    The emission of isoprene and other biogenic volatile organic compounds from vegetation plays an important role in tropospheric ozone (O3) formation. The potentially large expansion of isoprene emitting species (e.g., poplars) for bioenergy production might, therefore, impact tropospheric O3 formation. Using the eddy covariance technique we have simultaneously measured fluxes isoprene, O3 and of CO2 from a poplar (Populus) plantation grown for bioenergy production. We used the chemistry transport model LOTOS-EUROS to scale-up the isoprene emissions associated with the existing poplar plantations in Europe, and we assessed the impact of isoprene fluxes on ground level O3 concentrations. Our findings suggest that isoprene emissions from existing poplar-for-bioenergy plantations do not significantly affect the ground level of O3 concentration. Indeed the overall land in Europe covered with poplar plantations has not significantly changed over the last two decades despite policy incentives to produce bioenergy crops. The current surface area of isoprene emitting poplars-for-bioenergy remains too limited to significantly enhance O3 concentrations and thus to be considered a potential threat for air quality and human health. PMID:27615148

  9. Epigenetic Diversity of Clonal White Poplar (Populus alba L.) Populations: Could Methylation Support the Success of Vegetative Reproduction Strategy?

    PubMed

    Guarino, Francesco; Cicatelli, Angela; Brundu, Giuseppe; Heinze, Berthold; Castiglione, Stefano

    2015-01-01

    The widespread poplar populations of Sardinia are vegetatively propagated and live in different natural environments forming large monoclonal stands. The main goals of the present study were: i) to investigate/measure the epigenetic diversity of the poplar populations by determining their DNA methylation status; ii) to assess if and how methylation status influences population clustering; iii) to shed light on the changes that occur in the epigenome of ramets of the same poplar clone. To these purposes, 83 white poplar trees were sampled at different locations on the island of Sardinia. Methylation sensitive amplified polymorphism analysis was carried out on the genomic DNA extracted from leaves at the same juvenile stage. The study showed that the genetic biodiversity of poplars is quite limited but it is counterbalanced by epigenetic inter-population molecular variability. The comparison between MspI and HpaII DNA fragmentation profiles revealed that environmental conditions strongly influence hemi-methylation of the inner cytosine. The variable epigenetic status of Sardinian white poplars revealed a decreased number of population clusters. Landscape genetics analyses clearly demonstrated that ramets of the same clone were differentially methylated in relation to their geographic position. Therefore, our data support the notion that studies on plant biodiversity should no longer be restricted to genetic aspects, especially in the case of vegetatively propagated plant species.

  10. Strontium isotope detection of brine contamination in the East Poplar oil field, Montana

    USGS Publications Warehouse

    Peterman, Zell E.; Thamke, Joanna N.; Futa, Kiyoto; Oliver, Thomas A.

    2010-01-01

    Brine contamination of groundwater in the East Poplar oil field was first documented in the mid-1980s by the U.S. Geological Survey by using hydrochemistry, with an emphasis on chloride (Cl) and total dissolved solids concentrations. Supply wells for the City of Poplar are located downgradient from the oil field, are completed in the same shallow aquifers that are documented as contaminated, and therefore are potentially at risk of being contaminated. In cooperation with the Office of Environmental Protection of the Fort Peck Tribes, groundwater samples were collected in 2009 and 2010 from supply wells, monitor wells, and the Poplar River for analyses of major and trace elements, including strontium (Sr) concentrations and isotopic compositions. The ratio of strontium-87 to strontium-86 (87Sr/86Sr) is used extensively as a natural tracer in groundwater to detect mixing among waters from different sources and to study the effects of water/rock interaction. On a plot of the reciprocal strontium concentration against the 87Sr/86Sr ratio, mixtures of two end members will produce a linear array. Using this plotting method, data for samples from most of the wells, including the City of Poplar wells, define an array with reciprocal strontium values ranging from 0.08 to 4.15 and 87Sr/86Sr ratios ranging from 0.70811 to 0.70828. This array is composed of a brine end member with an average 87Sr/86Sr of 0.70822, strontium concentrations in excess of 12.5 milligrams per liter (mg/L), and chloride concentrations exceeding 8,000 mg/L mixing with uncontaminated water similar to that in USGS06-08 with 18.0 mg/L chloride, 0.24 mg/L strontium, and a 87Sr/86Sr ratio of 0.70811. The position of samples from the City of Poplar public-water supply wells within this array indicates that brine contamination has reached all three wells. Outliers from this array are EPU-4G (groundwater from the Cretaceous Judith River Formation), brine samples from disposal wells (Huber 5-D and EPU 1-D

  11. Exploring the Role of Plant Genetics to Enhance Soil Carbon Sequestration in Hybrid Poplar Plantations

    NASA Astrophysics Data System (ADS)

    Wullschleger, S. D.; Garten, C. T.; Classen, A. T.

    2008-12-01

    Atmospheric CO2 concentrations have increased in recent decades and are projected to increase even further during the coming century. These projections have prompted scientists and policy-makers to consider how plants and soils can be used to stabilize CO2 concentrations. Although storing carbon in terrestrial ecosystems represents an attractive near-term option for mitigating rising atmospheric CO2 concentrations, enhancing the sequestration potential of managed systems will require advancements in understanding the fundamental mechanisms that control rates of carbon transfer and turnover in plants and soils. To address this challenge, a mathematical model was constructed to evaluate how changes in particular plant traits and management practices could affect soil carbon storage beneath hybrid poplar (Populus) plantations. The model was built from four sub-models that describe aboveground biomass, root biomass, soil carbon dynamics, and soil nitrogen transformations for trees growing throughout a user-defined rotation. Simulations could be run over one or multiple rotations. A sensitivity analysis of the model indicated changes in soil carbon storage were affected by variables that could be linked to hybrid poplar traits like rates of aboveground production, partitioning of carbon to coarse and fine roots, and rates of root decomposition. A higher ratio of belowground to aboveground production was especially important and correlated directly with increased soil carbon storage. Faster decomposition rates for coarse and fine dead roots resulted in a greater loss of carbon to the atmosphere as CO2 and less residual organic carbon for transfer to the fast soil carbon pool. Hence, changes in root chemistry that prolonged dead root decomposition rates, a trait that is under potential genetic control, were predicted to increase soil carbon storage via higher soil carbon inputs. Nitrogen limitation of both aboveground biomass production and soil carbon sequestration was

  12. Biological Monitoring Program for East Fork Poplar Creek

    SciTech Connect

    Adams, S.M.; Christensen, S.W.; Greeley, M.S.jr; Hill, W.R.; Kszos, L.A.; McCarthy, J.F.; Peterson, M.J.; Ryon, M.G.; Smith, J.G.; Southworth, G.R.; Stewart, A.J.

    1998-10-15

    In May 1985, a National Pollutant Discharge Elimination System (NPDES) permit was issued for the Oak Ridge Y-12 Plant. As a condition of the permit, a Biologicai Monitoring and Abatement Program (BMAP) was developed to demonstrate that the effluent limitations established for the Y-12 Plant protect the classified uses of the receiving stream (East Fork Poplar Creek; EFPC), in particular, the growth and propagation of aquatic life (Lear et al. 1989). A second objective of the BMAP is to document the ecological effects resulting from the implementation of a water pollution control program designed to eliminate direct discharges of wastewaters to EFPC and to minimize the inadvertent release of pollutants to the environment. Because of the compiex nature of the discharges to EFPC and the temporal and spatial variability in the composition of the discharges, a comprehensive, integrated approach to biological monitoring was developed. A new permit was issued to the Y-12 Plant on April 28, 1995 and became effective on July 1, 1995. Biological monitoring continues to be required under the new permit. The BMAP consists of four major tasks that reflect different but complementary approaches to evaluating the effects of the Y-12 Plant discharges on the aquatic integrity of EFPC, These tasks are (1) toxicity monitoring, (2) biological indicator studies, (3) bioaccumuiation studies, and (4) ecological surveys of the periphyton, benthic macro invertebrate, and fish communities. Monitoring is currently being conducted at five sites, although sites maybe excluded and/or others added depending upon the specific objectives of the various tasks. Criteria used in selecting the sites include: (1) location of sampling sites used in other studies, (2) known or suspected sources of downstream impacts, (3) proximity to U.S. Department of Energy (DOE) Oak Ridge Reservation (ORR) boundaries, (4) concentration of mercury in the adjacent floodplain, (5) appropriate habitat distribution, and (6

  13. Electric Potential Variations on a Poplar: Beyond Electrokinetic Effects Associated With Sap Flow

    NASA Astrophysics Data System (ADS)

    Gibert, D.; Le Mouël, J.; Lambs, L.; Nicollin, F.; Conil, F.; Perrier, F.

    2004-12-01

    Electric potential has been monitored since December 2003 in the roots and at two circumferences and one vertical profile in a standing poplar (Populus incognitus). Electric potential is sampled using 5 mm diameter stainless steel rods, inserted 5 mm deep in the cambium, and is referenced to an unpolarizable Petiau electrode installed 80 cm deep in the soil. Various types of signals are observed. Transient signals with long relaxation times affecting some electrodes simultaneously, may be contact potentials triggered by condensation and evaporation. Diurnal variations are observed which present a seasonal variation. During winter, diurnal variations depend on the measurement point, with variable amplitudes and sometimes anticorrelations between electrodes. By contrast, a stable and coherent organization is established in the spring, with larger amplitudes, and lasts during summer. Such signals have been reported previously (Koppan et al., 2000; Morat et al., 1994; Fensom, 1963), have been interpreted as electrokinetic effects associated with sap flow. However, a comparison of the electrical signals with a measurement of the sap flow by a heat flow method, shows that the electrical variation, although clearly correlated to sap flow, is not simply proportional to it. In a living system, electrokinetic effects, in addition to thermoelectrical effects, are probably modified significantly by additional electrochemical effects, such as membrane diffusion potentials, ion active transport by proteins, and action potentials. Such effects have been evidenced in laboratory experiments with plants (e.g., Fromm and Hei, 1998). Electric potential variations in trees may thus reveal mechanisms not accessible by other methods, and maybe reveal new aspects of the physics of living systems. A better understanding of the electrical response of trees to meteorological, chemical or biological forcing may improve the knowledge of transfer processes between the soil and the atmosphere

  14. Effects of cutting orientation in poplar wood biomass size reduction on enzymatic hydrolysis sugar yield.

    PubMed

    Zhang, Meng; Ju, Xiaohui; Song, Xiaoxu; Zhang, Xiao; Pei, Z J; Wang, Donghai

    2015-10-01

    The aim of this study was to understand how cutting orientation in poplar wood biomass size reduction affects enzymatic hydrolysis sugar yield of wood particles. A metal cutting (milling) machine was used to produce poplar wood particles from three cutting orientations. Results showed that cutting orientation significantly affected enzymatic hydrolysis sugar yield of wood particles. In this study, size reduction from the optimum cutting orientation produced 50% more sugars than the other two cutting orientations. Particles from the cutting orientation with the highest sugar yield had a large enzyme accessible area (125 mg orange dye/g biomass, as evaluated by Simons' stain procedure) and low crystallinity (50% crystallinity index, as calculated by the Segal method). Furthermore, small particle size did not necessarily lead to improvement in enzymatic digestibility.

  15. Lonsdalea quercina subsp. populi subsp. nov., isolated from bark canker of poplar trees.

    PubMed

    Tóth, Tímea; Lakatos, Tamás; Koltay, András

    2013-06-01

    Seven Gram-negative bacterial strains were isolated from oozing bark canker of poplar (Populus × euramericana) trees in Hungary. They showed high (>98.3%) 16S rRNA gene sequence similarity to Lonsdalea quercina; however, they differed from this species in several phenotypic characteristics. Multilocus sequence analysis based on three housekeeping genes (gyrB, atpD and infB) revealed, and DNA-DNA hybridization analysis confirmed, that this group of bacterial strains forms a distinct lineage within the species Lonsdalea quercina. A detailed study of phenotypic and physiological characteristics confirmed the separation of isolates from poplars from other subspecies of L. quercina; therefore, a novel subspecies, Lonsdalea quercina subsp. populi, type strain NY060(T) (=DSM 25466(T)=NCAIM B 02483(T)), is proposed.

  16. Cometabolic degradation of trichloroethylene by Burkholderia cepacia G4 with poplar leaf homogenate.

    PubMed

    Kang, Jun Won; Doty, Sharon Lafferty

    2014-07-01

    Trichloroethylene (TCE), a chlorinated organic solvent, is one of the most common and widespread groundwater contaminants worldwide. Among the group of TCE-degrading aerobic bacteria, Burkholderia cepacia G4 is the best-known representative. This strain requires the addition of specific substrates, including toluene, phenol, and benzene, to induce the enzymes to degrade TCE. However, the substrates are toxic and introducing them into the soil can result in secondary contamination. In this study, poplar leaf homogenate containing natural phenolic compounds was tested for the ability to induce the growth of and TCE degradation by B. cepacia G4. The results showed that the G4 strain could grow and degrade TCE well with the addition of phytochemicals. The poplar leaf homogenate also functioned as an inducer of the toluene-ortho-monooxygenase (TOM) gene in B. cepacia G4.

  17. Use of wetlands for production of woody plants for fuels and petrochemical substitutes. [Alders, willows, poplars

    SciTech Connect

    Farnham, R.S.; Read, P.

    1981-03-01

    Work performed on this project in the past year has included the evaluations of natural stands productivity for wetland biomass species; propagation studies with alder, willow and poplar species; nursery establishment for production of cultivars and evaluation of wetland soils suitable for production of woody biomass species. Also a biomass research facility has been established in N. Minnesota suitable for long-term research and demonstration. Propagation research has included both micro and macro propagation techniques with native willows, selected willow clones from Sweden, alder seed selection from Finland and hybrid poplar clones from US Forest Service, Rhinelander, Wisconsin. Approximately 100,000 rooted plants will be available for field research by June 1, 1981.

  18. Predictive relationships for uptake of organic contaminants by hybrid poplar trees

    SciTech Connect

    Burken, J.G.; Schnoor, J.L.

    1998-11-01

    Twelve organic compounds commonly found at hazardous waste sites were studied for uptake by hybrid poplar trees. The vegetative uptake of many of these compounds has not previously been demonstrated for plant species being utilized for phytoremediation, such as hybrid poplar trees. Experiments were conducted hydroponically utilizing {sup 14}C-labeled compounds to ascertain translocation and fate. Predictive relationships for the translocation and partitioning to plant tissues were developed from the experimental data. Translocation and partitioning relationships based on compounds` octanol-water partitioning coefficients produced the best results, but the relationships did not allow for fully accurate prediction of each contaminant`s fate. Translocation and subsequent transpiration of volatile organic compounds (VOCs) from the leaves to the atmosphere was shown to be a significant pathway. As full-scale phytoremediation systems are deliberated, the pathways investigated here should be considered in terms of a contaminant removal mechanism and potential contamination of the vegetation.

  19. Tree water use and rainfall partitioning in a mature poplar-pasture system.

    PubMed

    Guevara-Escobar, A.; Edwards, W. R. N.; Morton, R. H.; Kemp, P. D.; Mackay, A. D.

    2000-01-01

    Traditionally, poplars (Populus) have been planted to control erosion on New Zealand's hill-slopes, because of their capacity to dry out and bind together the soil, by reducing effective rainfall and increasing evapotranspiration and soil strength. However, the effect of widely spaced poplars on the partitioning of soil water and rainfall has not been reported. This study determined rainfall partitioning for 18 mid-spring days in a mature P. deltoides (Bart. ex Marsh, Clone I78)-pasture association (37 stems per hectare, unevenly spaced at 16.4 +/- 0.4 m) and compared it with a traditional open pasture system in grazed areas of a hill environment. Tree transpiration was measured by the heat pulse technique. A time-driven mathematical model was used to set a zero offset, adjust anomalous values and describe simultaneous sap velocity time courses of trees. The model showed that daylight sap flow velocities can be represented with a nonlinear Beta function (R(2) > 0.98), and differences in the parameters representing the initiation, duration and conformation of the sap velocity can be tested statistically to discern tree transpiration differences during the day. Evapotranspiration was greater for the poplar-pasture association than for the open pasture (2.7-3.0 versus 2.2 mm day(-1)). The tree canopy alone contributed 0.92 mm day(-1) as transpiration and 1.37 mm day(-1) as interception, whereas evapotranspiration of the pasture understory was only 0.4-0.6 mm day(-1). Despite the higher water use of the poplar-pasture association, soil water in the 0-300 mm soil stratum was higher than, or similar to, that of the open pasture. Tree shading decreased evapotranspiration and pasture accumulation under the trees.

  20. Oxidative lime pretreatment of high-lignin biomass: poplar wood and newspaper.

    PubMed

    Chang, V S; Nagwani, M; Kim, C H; Holtzapple, M T

    2001-04-01

    Lime (Ca[OH]2) and oxygen (O2) were used to enhance the enzymatic digestibility of two kinds of high-lignin biomass: poplar wood and newspaper. The recommended pretreatment conditions for poplar wood are 150 degrees C, 6 h, 0.1 g of Ca(OH)2/g of dry biomass, 9 mL of water/g of dry biomass, 14.0 bar absolute oxygen, and a particle size of -10 mesh. Under these conditions, the 3-d reducing sugar yield of poplar wood using a cellulase loading of 5 filter paper units (FPU)/g of raw dry biomass increased from 62 to 565 mg of eq. glucose/g of raw dry biomass, and the 3-d total sugar (glucose + xylose) conversion increased from 6 to 77% of raw total sugars. At high cellulase loadings (e.g., 75 FPU/g of raw dry biomass), the 3-d total sugar conversion reached 97%. In a trial run with newspaper, using conditions of 140 degrees C, 3 h, 0.3 g of Ca(OH)2/g of dry biomass, 16 mL of water/g of dry biomass, and 7.1 bar absolute oxygen, the 3-d reducing sugar yield using a cellulase loading of 5 FPU/g of raw dry biomass increased from 240 to 565 mg of eq. glucose/g of raw dry biomass. A material balance study on poplar wood shows that oxidative lime pretreatment solubilized 38% of total biomass, including 78% of lignin and 49% of xylan; no glucan was removed. Ash increased because calcium was incorporated into biomass during the pretreatment. After oxidative lime pretreatment, about 21% of added lime could be recovered by CO2 carbonation.

  1. Sexual dimorphism floral microRNA profiling and target gene expression in andromonoecious poplar (Populus tomentosa).

    PubMed

    Song, Yuepeng; Ma, Kaifeng; Ci, Dong; Zhang, Zhiyi; Zhang, Deqiang

    2013-01-01

    Although the molecular basis of poplar sex-specific flower development remains largely unknown, increasing evidence indicates an essential role for microRNAs (miRNAs). The specific miRNA types and precise miRNA expression patterns in dioecious plant flower development remain unclear. Here, we used andromonoecious poplar, an exceptional model system, to eliminate the confounding effects of genetic background of dioecious plants. This system, combined with high-throughput sequencing and computational analysis, allowed us to characterize sex-specific miRNAomes from female and male flowers. Comparative miRNAome analysis combined with quantitative real-time PCR revealed the expression patterns of 27 miRNAs in poplar flower and showed that the targets of these miRNAs are involved in flower organogenesis, Ca(2+) transport, phytohormone synthesis and metabolism, and DNA methylation. This paper describes a complex regulatory network consisting of these miRNAs expressed in sex-specific flower development in a dioecious plant. The conserved and novel miRNA locations were annotated in the Populus trichocarpa genome. Among these, miRNA Pto-F70 and 4 targets are located in the sex-determination regions of chromosome XIX. Furthermore, two novel miRNAs, Pto-F47 and Pto-F68, were shown for the first time to be regulatory factors in phytohormone interactions. To our knowledge, this report is the first systematic investigation of sex-specific flower-related miRNAs and their targets in poplar, and it deepens our understanding of the important regulatory functions of miRNAs in female and male flower development in this dioecious plant.

  2. Recent Y chromosome divergence despite ancient origin of dioecy in poplars (Populus).

    PubMed

    Geraldes, A; Hefer, C A; Capron, A; Kolosova, N; Martinez-Nuñez, F; Soolanayakanahally, R Y; Stanton, B; Guy, R D; Mansfield, S D; Douglas, C J; Cronk, Q C B

    2015-07-01

    All species of the genus Populus (poplar, aspen) are dioecious, suggesting an ancient origin of this trait. Despite some empirical counter examples, theory suggests that nonrecombining sex-linked regions should quickly spread, eventually becoming heteromorphic chromosomes. In contrast, we show using whole-genome scans that the sex-associated region in Populus trichocarpa is small and much younger than the age of the genus. This indicates that sex determination is highly labile in poplar, consistent with recent evidence of 'turnover' of sex-determination regions in animals. We performed whole-genome resequencing of 52 P. trichocarpa (black cottonwood) and 34 Populus balsamifera (balsam poplar) individuals of known sex. Genomewide association studies in these unstructured populations identified 650 SNPs significantly associated with sex. We estimate the size of the sex-linked region to be ~100 kbp. All SNPs significantly associated with sex were in strong linkage disequilibrium despite the fact that they were mapped to six different chromosomes (plus 3 unmapped scaffolds) in version 2.2 of the reference genome. We show that this is likely due to genome misassembly. The segregation pattern of sex-associated SNPs revealed this to be an XY sex-determining system. Estimated divergence times of X and Y haplotype sequences (6-7 Ma) are much more recent than the divergence of P. trichocarpa (poplar) and Populus tremuloides (aspen). Consistent with this, in P. tremuloides, we found no XY haplotype divergence within the P. trichocarpa sex-determining region. These two species therefore have a different genomic architecture of sex, suggestive of at least one turnover event in the recent past.

  3. Short day length-induced decrease of cesium uptake without altering potassium uptake manner in poplar

    PubMed Central

    Noda, Yusaku; Furukawa, Jun; Aohara, Tsutomu; Nihei, Naoto; Hirose, Atsushi; Tanoi, Keitaro; Nakanishi, Tomoko M.; Satoh, Shinobu

    2016-01-01

    Short day length-induced alteration of potassium (K) localization in perennial trees is believed to be a mechanism for surviving and adapting to severe winters. To investigate the relationship between cesium (Cs) and K localizations, a model tree poplar, hybrid aspen T89, was employed. Under short day length conditions, the amount of 137Cs absorbed through the root and translocated to the root was drastically reduced, but 42K was not. Potassium uptake from the rhizosphere is mediated mainly by KUP/HAK/KT and CNGC transporters. In poplar, however, these genes were constantly expressed under short-day conditions except for a slight increase in the expression a KUP/HAK/KT gene six weeks after the onset of the short-day treatment. These results indicated that the suppression of 137Cs uptake was triggered by short day length but not regulated by competitive Cs+ and K+ transport. We hypothesize that there are separately regulated Cs+ and K+ transport systems in poplar. PMID:27924824

  4. Water consumption and biomass production of protoplast fusion lines of poplar hybrids under drought stress.

    PubMed

    Hennig, Anne; Kleinschmit, Jörg R G; Schoneberg, Sebastian; Löffler, Sonja; Janßen, Alwin; Polle, Andrea

    2015-01-01

    Woody crops such as poplars (Populus) can contribute to meet the increasing energy demand of a growing human population and can therefore enhance the security of energy supply. Using energy from biomass increases ecological sustainability as biomass is considered to play a pivotal role in abating climate change. Because areas for establishing poplar plantations are often confined to marginal sites drought tolerance is one important trait for poplar genotypes cultivated in short rotation coppice. We tested 9-month-old plants of four tetraploid Populus tremula (L.) × P. tremuloides (Michx.) lines that were generated by protoplast fusion and their diploid counterpart for water consumption and drought stress responses in a greenhouse experiment. The fusion lines showed equivalent or decreased height growth, stem biomass and total leaf area compared to the diploid line. The relative height increment of the fusion lines was not reduced compared to the diploid line when the plants were exposed to drought. The fusion lines were distinguished from the diploid counterpart by stomatal characteristics such as increased size and lower density. The changes in the stomatal apparatus did not affect the stomatal conductance. When exposed to drought the carbohydrate concentrations increased more strongly in the fusion lines than in the diploid line. Two fusion lines consumed significantly less water with regard to height growth, producing equivalent or increased relative stem biomass under drought compared to their diploid relative. Therefore, these tetraploid fusion lines are interesting candidates for short rotation biomass plantation on dry sites.

  5. Assessing the use of poplar tree systems as a landfill evapotranspiration barrier with the SHAW model.

    PubMed

    Preston, G M; McBride, R A

    2004-08-01

    The use of poplar tree systems (PTS) as evapotranspiration barriers on decommissioned landfills is gaining attention as an option for leachate management. This study involved field-testing the Simultaneous Heat and Water (SHAW) model for its ability to reliably estimate poplar transpiration, volumetric soil water content, and soil temperature at a landfill located in southern Ontario, Canada. The model was then used to estimate deep drainage and to ascertain the influence of a young PTS on the soil water balance of the landfill cover. The SHAW model tended to underestimate poplar transpiration [mean difference (MD) ranged from 0.33 to 3.55 mm on a daily total basis] and overestimate volumetric soil water content by up to 0.10 m3 m(-3). The model estimated soil temperature very well, particularly in the upper 1 m of the landfill cover (MD ranged from -0.1 to 1.6 x degrees C in this layer). The SHAW model simulations showed that deep drainage decreased appreciably with the presence of a young PTS largely through increased interception of rainfall, and that PTS have a good potential to act as effective evapotranspiration barriers in northern temperate climate zones.

  6. Effects of increased nitrogen supply on the lignification of poplar wood.

    PubMed

    Pitre, Frederic E; Pollet, Brigitte; Lafarguette, Florian; Cooke, Janice E K; MacKay, John J; Lapierre, Catherine

    2007-12-12

    The short-term influence of adequate and high nitrogen fertilization on poplar lignification was investigated. The high nitrogen supply decreased lignin staining in the newly formed secondary xylem, indicating that lignin deposition was affected. Acetyl bromide determinations gave a 9-10% decrease in lignin content; however, Klason lignin content was unchanged. Thioacidolysis showed that elevated N supply affected lignin structure such that there was a reduced frequency of lignin units involved in beta-O-4 bonds, a reduced syringyl/guaiacyl ratio, an increased frequency of p-hydroxyphenyl lignin units, more guaiacyl units with free phenolic groups, and more p-hydroxybenzoic acid ester-linked to poplar lignins. These features suggest that lignins from poplars grown under high N bear structural similarities to lignins formed during early stages of wood development. The findings also indicate that a gravitational stimulus inducing the formation of tension wood and high N availability lead to similar and additive effects on lignin content and structure.

  7. Investigation of horizontal gene transfer in poplar/Amanita muscaria ectomycorrhizas.

    PubMed

    Zhang, Chi; Hampp, Rüdiger; Nehls, Uwe

    2005-01-01

    Fine roots of forest trees form together with certain soil fungi symbiotic structures (ectomycorrhizas), where fungal hyphae are in intimate contact with plant cells. Due to root cell degeneration, plant DNA is released and could be taken up by the fungus. The possibility that horizontal gene transfer might result in a risk for the environment should be evaluated before a massive release of genetically engineered trees into nature occurs, even though only a few convincing examples of horizontal gene transfer are known. Transgenic poplars containing a construct of the Streptomyces hygroscopicus bar gene under the control of the Cochliobolus heterostrophus GPD (glyceraldehyde-3-phosphate dehydrogenase) promoter were generated by Agrobacterium-mediated transformation. The functionality of this construct in the ectomycorrhizal model fungus Amanita muscaria was previously verified by protoplast-based fungal transformation. 35,000 ectomycorrhizas, formed between transgenic poplars and non-transgenic A. muscaria hyphae, were isolated and transferred to selective agar plates. Putative herbicide-resistant fungal colonies were obtained after the first round of selection. However, none of these colonies survived a transfer onto fresh selection medium, nor did they contain the bar gene, indicating that no horizontal gene transfer from poplar to A. muscaria occurred during symbiosis under axenic conditions. However, since ectomycorrhizas are associated under natural conditions with viruses, bacteria and other fungi, these additional associations should be evaluated in future.

  8. Investigating Mass Transport Limitations on Xylan Hydrolysis During Dilute Acid Pretreatment of Poplar

    SciTech Connect

    Mittal, Ashutosh; Pilath, Heid M.; Parent, Yves; Chatterjee, Siddharth G.; Donohoe, Bryon S.; Yarbrough, John M.; Himmel, Michael E.; Nimlos, Mark R.; Johnson, David K.

    2014-04-28

    Mass transport limitations could be an impediment to achieving high sugar yields during biomass pretreatment and thus be a critical factor in the economics of biofuels production. The objective of this work was to study the mass transfer restrictions imposed by the structure of biomass on the hydrolysis of xylan during dilute acid pretreatment of biomass. Mass transfer effects were studied by pretreating poplar wood at particle sizes ranging from 10 micrometers to 10 mm. This work showed a significant reduction in the rate of xylan hydrolysis in poplar when compared to the intrinsic rate of hydrolysis for isolated xylan that is possible in the absence of mass transfer. In poplar samples we observed no significant difference in the rates of xylan hydrolysis over more than two orders of magnitude in particle size. It appears that no additional mass transport restrictions are introduced by increasing particle size from 10 micrometers to 10 mm. This work suggests that the rates of xylan hydrolysis in biomass particles are limited primarily by the diffusion of hydrolysis products out of plant cell walls. A mathematical description is presented to describe the kinetics of xylan hydrolysis that includes transport of the hydrolysis products through biomass into the bulk solution. The modeling results show that the effective diffusion coefficient of the hydrolysis products in the cell wall is several orders of magnitude smaller than typical values in other applications signifying the role of plant cell walls in offering resistance to diffusion of the hydrolysis products.

  9. White poplar (Populus alba) as a biomonitor of trace elements in contaminated riparian forests.

    PubMed

    Madejón, Paula; Marañón, Teodoro; Murillo, José M; Robinson, Brett

    2004-11-01

    Trees can be used to monitor the level of pollution of trace elements in the soil and atmosphere. In this paper, we surveyed the content of eight trace elements (As, Cd, Cu, Fe, Mn, Ni, Pb and Zn) in leaves and stems of white poplar (Populus alba) trees. We selected 25 trees in the riparian forest of the Guadiamar River (S. Spain), one year after this area was contaminated by a mine spill, and 10 trees in non-affected sites. The spill-affected soils had significantly higher levels of available cadmium (mean of 1.25 mg kg(-1)), zinc (117 mg kg(-1)), lead (63.3 mg kg(-1)), copper (58.0 mg kg(-1)) and arsenic (1.70 mg kg(-1)), than non-affected sites. The concentration of trace element in poplar leaves was positively and significantly correlated with the soil availability for cadmium and zinc, and to a lesser extent for arsenic (log-log relationship). Thus, poplar leaves could be used as biomonitors for soil pollution of Cd and Zn, and moderately for As.

  10. A System for Dosage-Based Functional Genomics in Poplar[OPEN

    PubMed Central

    2015-01-01

    Altering gene dosage through variation in gene copy number is a powerful approach to addressing questions regarding gene regulation, quantitative trait loci, and heterosis, but one that is not easily applied to sexually transmitted species. Elite poplar (Populus spp) varieties are created through interspecific hybridization, followed by clonal propagation. Altered gene dosage relationships are believed to contribute to hybrid performance. Clonal propagation allows for replication and maintenance of meiotically unstable ploidy or structural variants and provides an alternative approach to investigating gene dosage effects not possible in sexually propagated species. Here, we built a genome-wide structural variation system for dosage-based functional genomics and breeding of poplar. We pollinated Populus deltoides with gamma-irradiated Populus nigra pollen to produce >500 F1 seedlings containing dosage lesions in the form of deletions and insertions of chromosomal segments (indel mutations). Using high-precision dosage analysis, we detected indel mutations in ∼55% of the progeny. These indels varied in length, position, and number per individual, cumulatively tiling >99% of the genome, with an average of 10 indels per gene. Combined with future phenotype and transcriptome data, this population will provide an excellent resource for creating and characterizing dosage-based variation in poplar, including the contribution of dosage to quantitative traits and heterosis. PMID:26320226

  11. Water stress induces changes in polyphenol profile and antioxidant capacity in poplar plants (Populus spp.).

    PubMed

    Popović, B M; Štajner, D; Ždero-Pavlović, R; Tumbas-Šaponjac, V; Čanadanović-Brunet, J; Orlović, S

    2016-08-01

    This paper is aimed to characterize young poplar plants under the influence of water stress provoked by polyethileneglycol 6000 (PEG 6000). Three polar genotypes (M1, B229, and PE19/66) were grown in hydroponics and subjected to 100 and 200 mOsm PEG 6000 during six days. Polyphenol characterization, two enzymatic markers and antioxidant capacity in leaves and roots were investigated in stressed plants. Total phenol content, ferric reducing antioxidant capacity (FRAP) and DPPH antiradical power (DPPH ARP) were determined for estimating total antioxidant capacity. Polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) were determined as enzymatic markers. Polyphenol characterization of poplar samples was performed by HPLC-PDA analysis. All results were subjected to correlation analysis and principal component analysis (PCA). Inspite of the decrease of total phenol content in investigated genotypes, as well as total antioxidant capacity, some of polyphenols were affected by stress like flavonoids chrysin, myricetine, kaempferol and isoferulic acid in roots of B229 genotype (Populus deltoides). Genotype B229 also showed the increase of antioxidant capacity and PAL activity in root and leaves under stress what could be the indicator of the adaptability of poplar plants to water stress. Significant positive correlations were obtained between PAL, antioxidant capacity as well as phenolic acids among themselves. Chemometric evaluation showed close interdependence between flavonoids, FRAP, DPPH antiradical power and both investigated enzymes of polyphenol metabolism, PAL and PPO.

  12. Yield and spatial supply of bioenergy poplar and willow short-rotation coppice in the UK.

    PubMed

    Aylott, Matthew J; Casella, E; Tubby, I; Street, N R; Smith, P; Taylor, Gail

    2008-01-01

    Limited information on likely supply and spatial yield of bioenergy crops exists for the UK. Here, productivities are reported of poplar (Populus spp.) and willow (Salix spp.) grown as short-rotation coppice (SRC), using data from a large 49-site yield trial network. A partial least-squares regression technique was used to upscale actual field trial observations across England and Wales. Spatial productivity was then assessed under different land-use scenarios. Mean modelled yields ranged between 4.9 and 10.7 oven-dry tonnes (odt) ha(-1) yr(-1). Yields were generally higher in willow than in poplar, reflecting the susceptibility of older poplar genotypes to rust and their tendency for single stem dominance. Replacing 10% of arable land, 20% of improved grassland and 100% of set-aside grassland in England and Wales with the three most productive genotypes would yield 13 Modt of biomass annually (supplying 7% of UK electricity production or 48% of UK combined heat and power (CHP) production). Results show existing SRC genotypes have the immediate potential to be an important component of a mixed portfolio of renewables and that, in future, as new and improved genotypes become available, higher yields could extend this potential further.

  13. An In-Depth Understanding of Biomass Recalcitrance Using Natural Poplar Variants as the Feedstock

    SciTech Connect

    Meng, Xianzhi; Pu, Yunqiao; Yoo, Chang Geun; Li, Mi; Bali, Garima; Park, Doh-Yeon; Gjersing, Erica; Davis, Mark F.; Muchero, Wellington; Tuskan, Gerald A.; Tschaplinski, Timothy J.; Ragauskas, Arthur J.

    2016-12-12

    In an effort to better understand the biomass recalcitrance, six natural poplar variants were selected as feedstocks based on previous sugar release analysis. Compositional analysis and physicochemical characterizations of these poplars were performed and the correlations between these physicochemical properties and enzymatic hydrolysis yield were investigated. Gel permeation chromatography (GPC) and 13C solid state NMR were used to determine the degree of polymerization (DP) and crystallinity index (CrI) of cellulose, and the results along with the sugar release study indicated that cellulose DP likely played a more important role in enzymatic hydrolysis. Simons' stain revealed that the accessible surface area of substrate significantly varied among these variants from 17.3 to 33.2 mg g-1/biomass as reflected by dye adsorption, and cellulose accessibility was shown as one of the major factors governing substrates digestibility. HSQC and 31P NMR analysis detailed the structural features of poplar lignin variants. Overall, cellulose relevant factors appeared to have a stronger correlation with glucose release, if any, than lignin structural features. Lignin structural features, such as a phenolic hydroxyl group and the ratio of syringyl and guaiacyl (S/G), were found to have a more convincing impact on xylose release. Low lignin content, low cellulose DP, and high cellulose accessibility generally favor enzymatic hydrolysis; however, recalcitrance cannot be simply judged on any single substrate factor.

  14. An in-depth understanding of biomass recalcitrance using natural poplar variants as the feedstock

    SciTech Connect

    Meng, Xianzhi; Pu, Yunqiao; Yoo, Chang Geun; Li, Mi; Bali, Garima; Park, Doh -Yeon; Gjersing, Erica; Davis, Mark F.; Muchero, Wellington; Tuskan, Gerald A.; Tschaplinski, Timothy J.; Ragauskas, Arthur J.

    2016-12-12

    Here, in an effort to better understand the biomass recalcitrance, six natural poplar variants were selected as feedstocks based on previous sugar release analysis. Compositional analysis and physicochemical characterizations of these poplars were performed and the correlations between these physicochemical properties and enzymatic hydrolysis yield were investigated. Gel permeation chromatography (GPC) and 13C solid state NMR were used to determine the degree of polymerization (DP) and crystallinity index (CrI) of cellulose, and the results along with the sugar release study indicated that cellulose DP likely played a more important role in enzymatic hydrolysis. Simons’ stain revealed that the accessible surface area of substrate significantly varied among these variants from 17.3 to 33.2 mg g$–1\\atop{biomass}$ as reflected by dye adsorption, and cellulose accessibility was shown as one of the major factors governing substrates digestibility. HSQC and 31P NMR analysis detailed the structural features of poplar lignin variants. Overall, cellulose relevant factors appeared to have a stronger correlation with glucose release, if any, than lignin structural features. Lignin structural features, such as a phenolic hydroxyl group and the ratio of syringyl and guaiacyl (S/G), were found to have a more convincing impact on xylose release. Low lignin content, low cellulose DP, and high cellulose accessibility generally favor enzymatic hydrolysis; however, recalcitrance cannot be simply judged on any single substrate factor.

  15. An in-depth understanding of biomass recalcitrance using natural poplar variants as the feedstock

    DOE PAGES

    Meng, Xianzhi; Pu, Yunqiao; Yoo, Chang Geun; ...

    2016-12-12

    Here, in an effort to better understand the biomass recalcitrance, six natural poplar variants were selected as feedstocks based on previous sugar release analysis. Compositional analysis and physicochemical characterizations of these poplars were performed and the correlations between these physicochemical properties and enzymatic hydrolysis yield were investigated. Gel permeation chromatography (GPC) and 13C solid state NMR were used to determine the degree of polymerization (DP) and crystallinity index (CrI) of cellulose, and the results along with the sugar release study indicated that cellulose DP likely played a more important role in enzymatic hydrolysis. Simons’ stain revealed that the accessible surface area of substrate significantly varied among these variants from 17.3 to 33.2 mg gmore » $$–1\\atop{biomass}$$ as reflected by dye adsorption, and cellulose accessibility was shown as one of the major factors governing substrates digestibility. HSQC and 31P NMR analysis detailed the structural features of poplar lignin variants. Overall, cellulose relevant factors appeared to have a stronger correlation with glucose release, if any, than lignin structural features. Lignin structural features, such as a phenolic hydroxyl group and the ratio of syringyl and guaiacyl (S/G), were found to have a more convincing impact on xylose release. Low lignin content, low cellulose DP, and high cellulose accessibility generally favor enzymatic hydrolysis; however, recalcitrance cannot be simply judged on any single substrate factor.« less

  16. Short rotation coppice culture of willows and poplars as energy crops on metal contaminated agricultural soils.

    PubMed

    Ruttens, Ann; Boulet, Jana; Weyens, Nele; Smeets, Karen; Adriaensen, Kristin; Meers, Erik; Van Slycken, Stijn; Tack, Filip; Meiresonne, Linda; Thewys, Theo; Witters, Nele; Carleer, Robert; Dupae, Joke; Vangronsveld, Jaco

    2011-01-01

    Phytoremediation, more precisely phytoextraction, has been placed forward as an environmental friendly remediation technique, that can gradually reduce increased soil metal concentrations, in particular the bioavailable fractions. The aim of this study was to investigate the possibilities of growing willows and poplars under short rotation coppice (SRC) on an acid, poor, sandy metal contaminated soil, to combine in this way soil remediation by phytoextraction on one hand, and production of biomass for energy purposes on the other. Above ground biomass productivities were low for poplars to moderate for willows, which was not surprising, taking into account the soil conditions that are not very favorable for growth of these trees. Calculated phytoextraction efficiency was much longer for poplars than these for willows. We calculated that for phytoextraction in this particular case it would take at least 36 years to reach the legal threshold values for cadmium, but in combination with production of feedstock for bioenergy processes, this type of land use can offer an alternative income for local farmers. Based on the data of the first growing cycle, for this particular case, SRC of willows should be recommended.

  17. Boron accumulation and toxicity in hybrid poplar (Populus nigra × euramericana).

    PubMed

    Rees, Rainer; Robinson, Brett H; Menon, Manoj; Lehmann, Eberhard; Günthardt-Goerg, Madeleine S; Schulin, Rainer

    2011-12-15

    Poplars accumulate high B concentrations and are thus used for the phytomanagement of B contaminated soils. Here, we performed pot experiments in which Populus nigra × euramericana were grown on a substrate with B concentrations ranging from 13 to 280 mg kg(-1) as H(3)BO(3). Salix viminalis, Brassica juncea, and Lupinus albus were grown under some growing conditions for comparison. Poplar growth was unaffected at soil B treatment levels up to 93 mg kg(-1). Growth was progressively reduced at levels of 168 and 280 mg kg(-1). None of the other species survived at these substrate B levels. At leaf B concentrations <900 mg kg(-1) only <10% of the poplar leaf area showed signs of toxicity. Neutron radiography revealed that chlorotic leaf tissues had B concentrations of 1000-2000 mg kg(-1), while necrotic tissues had >2000 mg kg(-1). Average B concentrations of up to 3500 mg kg(-1) were found in leaves, while spots within leaves had concentrations >7000 mg kg(-1), showing that B accumulation in leaf tissue continued even after the onset of necrosis. The B accumulation ability of P. nigra × euramericana is associated with B hypertolerance in the living tissue and storage of B in dead leaf tissue.

  18. Host genotype shapes the foliar fungal microbiome of balsam poplar (Populus balsamifera).

    PubMed

    Bálint, Miklós; Tiffin, Peter; Hallström, Björn; O'Hara, Robert B; Olson, Matthew S; Fankhauser, Johnathon D; Piepenbring, Meike; Schmitt, Imke

    2013-01-01

    Foliar fungal communities of plants are diverse and ubiquitous. In grasses endophytes may increase host fitness; in trees, their ecological roles are poorly understood. We investigated whether the genotype of the host tree influences community structure of foliar fungi. We sampled leaves from genotyped balsam poplars from across the species' range, and applied 454 amplicon sequencing to characterize foliar fungal communities. At the time of the sampling the poplars had been growing in a common garden for two years. We found diverse fungal communities associated with the poplar leaves. Linear discriminant analysis and generalized linear models showed that host genotypes had a structuring effect on the composition of foliar fungal communities. The observed patterns may be explained by a filtering mechanism which allows the trees to selectively recruit fungal strains from the environment. Alternatively, host genotype-specific fungal communities may be present in the tree systemically, and persist in the host even after two clonal reproductions. Both scenarios are consistent with host tree adaptation to specific foliar fungal communities and suggest that there is a functional basis for the strong biotic interaction.

  19. Water consumption and biomass production of protoplast fusion lines of poplar hybrids under drought stress

    PubMed Central

    Hennig, Anne; Kleinschmit, Jörg R. G.; Schoneberg, Sebastian; Löffler, Sonja; Janßen, Alwin; Polle, Andrea

    2015-01-01

    Woody crops such as poplars (Populus) can contribute to meet the increasing energy demand of a growing human population and can therefore enhance the security of energy supply. Using energy from biomass increases ecological sustainability as biomass is considered to play a pivotal role in abating climate change. Because areas for establishing poplar plantations are often confined to marginal sites drought tolerance is one important trait for poplar genotypes cultivated in short rotation coppice. We tested 9-month-old plants of four tetraploid Populus tremula (L.) × P. tremuloides (Michx.) lines that were generated by protoplast fusion and their diploid counterpart for water consumption and drought stress responses in a greenhouse experiment. The fusion lines showed equivalent or decreased height growth, stem biomass and total leaf area compared to the diploid line. The relative height increment of the fusion lines was not reduced compared to the diploid line when the plants were exposed to drought. The fusion lines were distinguished from the diploid counterpart by stomatal characteristics such as increased size and lower density. The changes in the stomatal apparatus did not affect the stomatal conductance. When exposed to drought the carbohydrate concentrations increased more strongly in the fusion lines than in the diploid line. Two fusion lines consumed significantly less water with regard to height growth, producing equivalent or increased relative stem biomass under drought compared to their diploid relative. Therefore, these tetraploid fusion lines are interesting candidates for short rotation biomass plantation on dry sites. PMID:26042130

  20. Essential Role of Caffeoyl Coenzyme A O-Methyltransferase in Lignin Biosynthesis in Woody Poplar Plants

    PubMed Central

    Zhong, Ruiqin; Morrison, W. Herbert; Himmelsbach, David S.; Poole, Farris L.; Ye, Zheng-Hua

    2000-01-01

    Caffeoyl coenzyme A O-methyltransferase (CCoAOMT) has recently been shown to participate in lignin biosynthesis in herbacious tobacco plants. Here, we demonstrate that CCoAOMT is essential in lignin biosynthesis in woody poplar (Populus tremula × Populus alba) plants. In poplar stems, CCoAOMT was found to be expressed in all lignifying cells including vessel elements and fibers as well as in xylem ray parenchyma cells. Repression of CCoAOMT expression by the antisense approach in transgenic poplar plants caused a significant decrease in total lignin content as detected by both Klason lignin assay and Fourier-transform infrared spectroscopy. The reduction in lignin content was the result of a decrease in both guaiacyl and syringyl lignins as determined by in-source pyrolysis mass spectrometry. Fourier-transform infrared spectroscopy indicated that the reduction in lignin content resulted in a less condensed and less cross-linked lignin structure in wood. Repression of CCoAOMT expression also led to coloration of wood and an elevation of wall-bound p-hydroxybenzoic acid. Taken together, these results indicate that CCoAOMT plays a dominant role in the methylation of the 3-hydroxyl group of caffeoyl CoA, and the CCoAOMT-mediated methylation reaction is essential to channel substrates for 5-methoxylation of hydroxycinnamates. They also suggest that antisense repression of CCoAOMT is an efficient means for genetic engineering of trees with low lignin content. PMID:11027707

  1. The proteomics of nitrogen remobilization in poplar bark

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seasonal nitrogen (N) cycling in temperate deciduous trees involves the accumulation of bark storage proteins (BSPs), a class of vegetative storage proteins in phloem parenchyma and xylem ray cells. BSPs are anabolized using recycled N in the form of amino acids after autumn leaf senescence and lat...

  2. Evaluation of Lower East Fork Poplar Creek Mercury Sources

    SciTech Connect

    Watson, David B.; Brooks, Scott C.; Mathews, Teresa J.; Bevelhimer, Mark S.; DeRolph, Chris; Brandt, Craig C.; Peterson, Mark J.; Ketelle, Richard

    2016-06-01

    This report summarizes a 3-year research project undertaken to better understand the nature and magnitude of mercury (Hg) fluxes in East Fork Poplar Creek (EFPC). This project addresses the requirements of Action Plan 1 in the 2011 Oak Ridge Reservation-wide Comprehensive Environmental Response, Compensation, and Liability Act Five Year Review (FYR). The Action Plan is designed to address a twofold 2011 FYR issue: (1) new information suggests mobilization of mercury from the upper and lower EFPC streambeds and stream banks is the primary source of mercury export during high-flow conditions, and (2) the current Record of Decision did not address the entire hydrologic system and creek bank or creek bed sediments. To obtain a more robust watershed-scale understanding of mercury sources and processes in lower EFPC (LEFPC), new field and laboratory studies were coupled with existing data from multiple US Department of Energy programs to develop a dynamic watershed and bioaccumulation model. LEFPC field studies for the project focused primarily on quantification of streambank erosion and an evaluation of mercury dynamics in shallow groundwater adjacent to LEFPC and potential connection to the surface water. The approach to the stream bank study was innovative in using imagery from kayak floats’ surveys from the headwaters to the mouth of EFPC to estimate erosion, coupled with detailed bank soil mercury analyses. The goal of new field assessments and modeling was to generate a more holistic and quantitative understanding of the watershed and the sources, flux, concentration, transformation, and bioaccumulation of inorganic mercury (IHg) and methylmercury (MeHg). Model development used a hybrid approach that dynamically linked a spreadsheet-based physical and chemical watershed model to a systems dynamics, mercury bioaccumulation model for key fish species. The watershed model tracks total Hg and MeHg fluxes and concentrations by examining upstream inputs, floodplain

  3. Genetic Modification of Short Rotation Poplar Biomass Feedstock for Efficient Conversion to Ethanol

    SciTech Connect

    Dinus, R.J.

    2000-08-30

    The Bioenergy Feedstock Development Program, Environmental Sciences Division, Oak Ridge National Laboratory is developing poplars (Populus species and hybrids) as sources of renewable energy, i.e., ethanol. Notable increases in adaptability, volume productivity, and pest/stress resistance have been achieved via classical selection and breeding and intensified cultural practices. Significant advances have also been made in the efficiencies of harvesting and handling systems. Given these and anticipated accomplishments, program leaders are considering shifting some attention to genetically modifying feedstock physical and chemical properties, so as to improve the efficiency with which feedstocks can be converted to ethanol. This report provides an in-depth review and synthesis of opportunities for and feasibilities of genetically modifying feedstock qualities via classical selection and breeding, marker-aided selection and breeding, and genetic transformation. Information was collected by analysis of the literature, with emphasis on that published since 1995, and interviews with prominent scientists, breeders, and growers. Poplar research is well advanced, and literature is abundant. The report therefore primarily reflects advances in poplars, but data from other species, particularly other shortrotation hardwoods, are incorporated to fill gaps. An executive summary and recommendations for research, development, and technology transfer are provided immediately after the table of contents. The first major section of the report describes processes most likely to be used for conversion of poplar biomass to ethanol, the various physical and chemical properties of poplar feedstocks, and how such properties are expected to affect process efficiency. The need is stressed for improved understanding of the impact of change on both overall process and individual process step efficiencies. The second part documents advances in trait measurement instrumentation and methodology

  4. Conversion from cropland to short rotation coppice willow and poplar: Accumulation of soil organic carbon

    NASA Astrophysics Data System (ADS)

    Georgiadis, Petros; Stupak, Inge; Vesterdal, Lars; Raulund-Rasmussen, Karsten

    2015-04-01

    Increased demand for bioenergy has intensified the production of Short Rotation Coppice (SRC) willow and poplar in temperate zones. We used a combined chronosequence and paired plot approach to study the potential of SRC willow and poplar stands to increase the soil carbon stock compared to stocks of the previous arable land-use. The study focused on well-drained soils. We sampled soil from 30 SRC stands in Denmark and southern Sweden including soils from their adjacent arable fields. The 18 willow and 12 poplar stands formed a chronosequence ranging between 4 and 29 years after conversion. The soil was sampled both with soil cores taken by fixed depths of 0-5, 5-10, 10-15, 15-25, and 25-40 cm and by genetic horizons from soil pits to 1m depth. The aim of the study was to estimate the difference and the ratio between soil carbon contents of the SRC and annual crop land and analyze the results as a chronosequence to examine the effect of age after conversion on the difference. Covariates such as soil type, fertilization type and harvest frequency were also taken into account. Preliminary results suggest an overall increase in carbon stocks over time with average accumulation rates ranging from 0.25 to 0.4 Mg ha-1 yr-1 in willow and poplar stands. Poplar stands had higher rates of C gain, probably due to less frequent harvesting. The differences in carbon between the SRC and the paired cropland were initially negative but changed to positive over time, implying loss of carbon after conversion and a later gain in soil carbon with stand age. Pairwise differences ranged from -25 Mg C ha-1 to 37 Mg C ha-1 for the top 40 cm. The carbon stock ratio of the SRC stand to the arable land was estimated to minimize the effect of site-related factors. The results of this analysis suggested that the ratio increased significantly with age after conversion for the top 10 cm of the soil, both for poplar and willow. A slight increase with age was also noticed at the deeper depths, but

  5. [Effects of 6-BA and AsA on photosynthesis photoinhibition of attached poplar leaves under osmotic stress of root].

    PubMed

    Feng, Yulong; Ma, Yongshuang; Feng, Zhili

    2004-12-01

    In order to know more about the relationships between photosynthesis photoinhibition and reactive oxygen species metabolism, the effects of 6-benzyladenine (6-BA) and ascorbate (AsA) on net photosynthetic rate (Pn), apparent quantum yield (AQY), superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities, O2-* generation rate, and H2O2 and malondialdehyde (MDA) contents were studied with attached leaves of poplar clone seedlings under osmotic stress of root. Under osmotic stress, the photosynthesis photoinhibition of attached poplar leaves, judged by the significant decrease of Pn and AQY, was aggravated, and the balance of reactive oxygen species metabolism was destroyed. The superoxide dismutase (SOD) activity increased, but ascorbate peroxidase (APX) activity decreased. In the meantime, the O2-* generation rate and the contents of H2O2 and malondialdehyde (MDA) increased. When osmotic stressed poplar seedlings were pretreated with 6-BA and AsA, the activities of SOD and APX increased, O2-* generation rate and H2O2 and MDA contents decreased, and photosynthesis photoinhibition was alleviated. The contents of reactive oxygen species and MDA in poplar leaves were negatively correlated with net photosynthetic rate and apparent quantum yield. It's indicated that the photosynthesis photoinhibition of attached leaves of poplar clone seedlings had intrinsic relations with the accumulation of reactive oxygen species under osmotic stress of root, and the alleviation effects of 6-BA and AsA on photosynthesis photoinhibition were related to their promotion effects to the scavenging system of reactive oxygen species.

  6. [Time lag effect between poplar' s sap flow velocity and microclimate factors in agroforestry system in West Liaoning Province].

    PubMed

    Di, Sun; Guan, De-xin; Yuan, Feng-hui; Wang, An-zhi; Wu, Jia-bing

    2010-11-01

    By using Granier's thermal dissipation probe, the sap flow velocity of the poplars in agroforestry system in west Liaoning was continuously measured, and the microclimate factors were measured synchronously. Dislocation contrast method was applied to analyze the sap flow velocity and corresponding air temperature, air humidity, net radiation, and vapor pressure deficit to discuss the time lag effect between poplar' s sap flow velocity and microclimate factors on sunny days. It was found that the poplar's sap flow velocity advanced of air temperature, air humidity, and vapor pressure deficit, and lagged behind net radiation. The sap flow velocity in June, July, August, and September was advanced of 70, 30, 50, and 90 min to air temperature, of 80, 30, 40, and 90 min to air humidity, and of 90, 50, 70, and 120 min to vapor pressure deficit, but lagged behind 10, 10, 40, and 40 min to net radiation, respectively. The time lag time of net radiation was shorter than that of air temperature, air humidity, and vapor pressure. The regression analysis showed that in the cases the time lag effect was contained and not, the determination coefficients between comprehensive microclimate factor and poplar's sap flow velocity were 0.903 and 0.855, respectively, indicating that when the time lag effect was contained, the determination coefficient was ascended by 2.04%, and thus, the simulation accuracy of poplar's sap flow velocity was improved.

  7. Overexpression of bacterial γ-glutamylcysteine synthetase mediates changes in cadmium influx, allocation and detoxification in poplar.

    PubMed

    He, Jiali; Li, Hong; Ma, Chaofeng; Zhang, Yanli; Polle, Andrea; Rennenberg, Heinz; Cheng, Xingqi; Luo, Zhi-Bin

    2015-01-01

    Overexpression of bacterial γ-glutamylcysteine synthetase in the cytosol of Populus tremula × P. alba produces higher glutathione (GSH) concentrations in leaves, thereby indicating the potential for cadmium (Cd) phytoremediation. However, the net Cd(2+) influx in association with H(+) /Ca(2+) , Cd tolerance, and the underlying molecular and physiological mechanisms are uncharacterized in these poplars. We assessed net Cd(2+) influx, Cd tolerance and the transcriptional regulation of several genes involved in Cd(2+) transport and detoxification in wild-type and transgenic poplars. Poplars exhibited highest net Cd(2+) influxes into roots at pH 5.5 and 0.1 mM Ca(2+) . Transgenics had higher Cd(2+) uptake rates and elevated transcript levels of several genes involved in Cd(2+) transport and detoxification compared with wild-type poplars. Transgenics exhibited greater Cd accumulation in the aerial parts than wild-type plants in response to Cd(2+) exposure. Moreover, transgenic poplars had lower concentrations of O2 ˙(-) and H2 O2 ; higher concentrations of total thiols, GSH and oxidized GSH in roots and/or leaves; and stimulated foliar GSH reductase activity compared with wild-type plants. These results indicate that transgenics are more tolerant of 100 μM Cd(2+) than wild-type plants, probably due to the GSH-mediated induction of the transcription of genes involved in Cd(2+) transport and detoxification.

  8. Successful crossings with early flowering transgenic poplar: interspecific crossings, but not transgenesis, promoted aberrant phenotypes in offspring.

    PubMed

    Hoenicka, Hans; Lehnhardt, Denise; Nilsson, Ove; Hanelt, Dieter; Fladung, Matthias

    2014-10-01

    In forest tree species, the reproductive phase is reached only after many years or even decades of juvenile growth. Different early flowering systems based on the genetic transfer of heat-shock promoter driven flowering-time genes have been proposed for poplar; however, no fertile flowers were reported until now. Here, we studied flower and pollen development in both HSP::AtFT and wild-type male poplar in detail and developed an optimized heat treatment protocol to obtain fertile HSP::AtFT flowers. Anthers from HSP::AtFT poplar flowers containing fertile pollen grains showed arrested development in stage 12 instead of reaching phase 13 as do wild-type flowers. Pollen grains could be isolated under the binocular microscope and were used for intra- and interspecific crossings with wild-type poplar. F1-seedlings segregating the HSP::AtFT gene construct according to Mendelian laws were obtained. A comparison between intra- and interspecific crossings revealed that genetic transformation had no detrimental effects on F1-seedlings. However, interspecific crossings, a broadly accepted breeding method, produced 47% seedlings with an aberrant phenotype. The early flowering system presented in this study opens new possibilities for accelerating breeding of poplar and other forest tree species. Fast breeding and the selection of transgene-free plants, once the breeding process is concluded, can represent an attractive alternative even under very restrictive regulations.

  9. Genome survey and characterization of endophytic bacteria exhibiting a beneficial effect on growth and development of poplar trees.

    PubMed

    Taghavi, Safiyh; Garafola, Craig; Monchy, Sébastien; Newman, Lee; Hoffman, Adam; Weyens, Nele; Barac, Tanja; Vangronsveld, Jaco; van der Lelie, Daniel

    2009-02-01

    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 representatives for the dominant genera of endophytic gammaproteobacteria, we selected Enterobacter sp. strain 638, Stenotrophomonas maltophilia R551-3, Pseudomonas putida W619, and Serratia proteamaculans 568 for genome sequencing and analysis of their plant growth-promoting effects, including root development. Derivatives of these endophytes, labeled with gfp, were also used to study the colonization of their poplar hosts. In greenhouse studies, poplar cuttings (Populus deltoides x Populus nigra DN-34) inoculated with Enterobacter sp. strain 638 repeatedly showed the highest increase in biomass production compared to cuttings of noninoculated control plants. Sequence data combined with the analysis of their metabolic properties resulted in the identification of many putative mechanisms, including carbon source utilization, that help these endophytes to thrive within a plant environment and to potentially affect the growth and development of their plant hosts. Understanding the interactions between endophytic bacteria and their host plants should ultimately result in the design of strategies for improved poplar biomass production on marginal soils as a feedstock for biofuels.

  10. Comparison of transcriptional profiles of Clostridium thermocellum grown on cellobiose and pretreated yellow poplar using RNA-Seq

    PubMed Central

    Wei, Hui; Fu, Yan; Magnusson, Lauren; Baker, John O.; Maness, Pin-Ching; Xu, Qi; Yang, Shihui; Bowersox, Andrew; Bogorad, Igor; Wang, Wei; Tucker, Melvin P.; Himmel, Michael E.; Ding, Shi-You

    2014-01-01

    The anaerobic, thermophilic bacterium, Clostridium thermocellum, secretes multi-protein enzyme complexes, termed cellulosomes, which synergistically interact with the microbial cell surface and efficiently disassemble plant cell wall biomass. C. thermocellum has also been considered a potential consolidated bioprocessing (CBP) organism due to its ability to produce the biofuel products, hydrogen, and ethanol. We found that C. thermocellum fermentation of pretreated yellow poplar (PYP) produced 30 and 39% of ethanol and hydrogen product concentrations, respectively, compared to fermentation of cellobiose. RNA-seq was used to analyze the transcriptional profiles of these cells. The PYP-grown cells taken for analysis at the late stationary phase showed 1211 genes up-regulated and 314 down-regulated by more than two-fold compared to the cellobiose-grown cells. These affected genes cover a broad spectrum of specific functional categories. The transcriptional analysis was further validated by sub-proteomics data taken from the literature; as well as by quantitative reverse transcription-PCR (qRT-PCR) analyses of selected genes. Specifically, 47 cellulosomal protein-encoding genes, genes for 4 pairs of SigI-RsgI for polysaccharide sensing, 7 cellodextrin ABC transporter genes, and a set of NAD(P)H hydogenase and alcohol dehydrogenase genes were up-regulated for cells growing on PYP compared to cellobiose. These genes could be potential candidates for future studies aimed at gaining insight into the regulatory mechanism of this organism as well as for improvement of C. thermocellum in its role as a CBP organism. PMID:24782837

  11. Impact of moderate Fe excess under Cd stress on the photosynthetic performance of poplar (Populus jacquemontiana var. glauca cv. Kopeczkii).

    PubMed

    Sárvári, Eva; Solti, Adám; Basa, Brigitta; Mészáros, Ilona; Lévai, László; Fodor, Ferenc

    2011-05-01

    Cadmium interference with Fe nutrition has a strong impact on the development and efficiency of the photosynthetic apparatus. To shed more light on the interaction between Fe and Cd, it was studied how iron given in moderate excess under Cd stress affects the development and functioning of chlorophyll-protein complexes. Poplar plants grown in hydroponics up to four-leaf stage were treated with 10 μM Cd(NO₃)₂ in the presence of 50 μM Fe([III])-citrate as iron supply (5xFe + Cad) for two weeks. Though leaf area growth was inhibited similarly to that of Cad (10 μM Cd(NO₃)₂ + 10 μM Fe([III])-citrate) plants, chlorophyll content, ¹⁴CO₂ fixation and quenching parameters calculated from PAM fluorescence induction measurements were control-like in 5xFe+Cad leaves. Increased chloroplast iron content (measured photometrically by the bathophenanthroline disulfonate method) without changes in the iron and cadmium content of leaves (determined by inductively coupled plasma mass spectrometry) pointed out that a key factor in the observed protection of photosynthesis is the iron-excess-induced redistribution of iron in the leaf. However, the chlorophyll a/b ratio and the chlorophyll-protein pattern obtained by Deriphat PAGE remained similar to that of Cad leaves. The decreased amount of PSII core and PSI in mature and developing leaves, respectively, refers to developmental stage-dependent remodelling of thylakoids in the presence of Cd. The results underline not only the beneficial effect of iron excess under Cd stress, but also refer to the importance of a proper Fe/Cd ratio and light environment to avoid its possible harmful effects.

  12. A heterogeneous boron distribution in soil influences the poplar root system architecture development

    NASA Astrophysics Data System (ADS)

    Rees, R.; Robinson, B. H.; Hartmann, S.; Lehmann, E.; Schulin, R.

    2009-04-01

    Poplars are well suited for the phytomanagement of boron (B)-contaminated sites, due to their high transpiration rate and tolerance to elevated soil B concentrations. However, the uptake and the fate of B in poplar stands are not well understood. This information is crucial to improve the design of phytomanagement systems, where the primary role of poplars is to reduce B leaching by reducing the water flux through the contaminated material. Like other trace elements, B occurs heterogeneously in soils. Concentrations can differ up to an order of magnitude within centimetres. These gradients affect plant root growth and thus via preferential flow along the roots water and mass transport in soils to ground and surface waters. Generally there are three possible reactions of plant roots to patches with elevated trace element concentrations in soils: indifference, avoidance, or foraging. While avoidance or indifference might seem to be the most obvious strategies, foraging cannot be excluded a priori, because of the high demand of poplars for B compared to other tree species. We aimed to determine the rooting strategies of poplars in soils where B is either homo- or heterogeneously distributed. We planted 5 cm cuttings of Populus tremula var. Birmensdorf clones in aluminum (Al) containers with internal dimensions of 64 x 67 x 1.2 cm. The soil used was subsoil from northern Switzerland with a naturally low B and organic C concentration. We setup two treatments and a control with three replicates each. We spiked a bigger and a smaller portion of the soil with the same amount of B(OH)3-salt, in order to obtain soil concentrations of 7.5 mg B kg-1 and 20 mg B kg-1. We filled the containers with (a) un-spiked soil, (b) the 7.5 mg B kg-1 soil and (c) heterogeneously. The heterogeneous treatment consisted of one third 20 mg B kg-1 soil and two thirds control soil. We grew the poplars in a small greenhouse over 2 months and from then on in a climate chamber for another 3 months

  13. QTLs for Woolly Poplar Aphid (Phloeomyzus passerinii L.) Resistance Detected in an Inter-Specific Populus deltoides x P. nigra Mapping Population.

    PubMed

    Carletti, Giorgia; Carra, Andrea; Allegro, Gianni; Vietto, Lorenzo; Desiderio, Francesca; Bagnaresi, Paolo; Gianinetti, Alberto; Cattivelli, Luigi; Valè, Giampiero; Nervo, Giuseppe

    2016-01-01

    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 countries. In this work we present two high density linkage maps in poplar obtained by a genotyping by sequencing (GBS) approach and the identification of QTLs involved in Ph. passerinii resistance. A total of 5,667 polymorphic markers (5,606 SNPs and 61 SSRs) identified on expressed sequences have been used to genotype 131 plants of an F1 population P ×canadensis obtained by an interspecific mate between Populus deltoides (resistant to woolly poplar aphid) and Populus nigra (susceptible to woolly poplar aphid). The two linkage maps, obtained following the two-way pseudo-testcross mapping strategy, have been used to investigate the genetic bases of woolly poplar aphid resistance. One major QTL and two QTLs with minor effects (mapped on LGV, LGXVI and LG XIX) explaining the 65.8% of the genetic variance observed in the progeny in response to Ph. passerinii attack were found. The high density coverage of functional markers allowed the identification of three genes belonging to disease resistance pathway as putative candidates for P. deltoides resistance to woolly poplar aphid. This work is the first report on genetic of woolly poplar aphid genetic resistance and the resistant loci associated markers identified represent a valuable tool in resistance poplar breeding programs.

  14. QTLs for Woolly Poplar Aphid (Phloeomyzus passerinii L.) Resistance Detected in an Inter-Specific Populus deltoides x P. nigra Mapping Population

    PubMed Central

    Carletti, Giorgia; Carra, Andrea; Allegro, Gianni; Vietto, Lorenzo; Desiderio, Francesca; Bagnaresi, Paolo; Gianinetti, Alberto; Cattivelli, Luigi; Valè, Giampiero; Nervo, Giuseppe

    2016-01-01

    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 countries. In this work we present two high density linkage maps in poplar obtained by a genotyping by sequencing (GBS) approach and the identification of QTLs involved in Ph. passerinii resistance. A total of 5,667 polymorphic markers (5,606 SNPs and 61 SSRs) identified on expressed sequences have been used to genotype 131 plants of an F1 population P ×canadensis obtained by an interspecific mate between Populus deltoides (resistant to woolly poplar aphid) and Populus nigra (susceptible to woolly poplar aphid). The two linkage maps, obtained following the two-way pseudo-testcross mapping strategy, have been used to investigate the genetic bases of woolly poplar aphid resistance. One major QTL and two QTLs with minor effects (mapped on LGV, LGXVI and LG XIX) explaining the 65.8% of the genetic variance observed in the progeny in response to Ph. passerinii attack were found. The high density coverage of functional markers allowed the identification of three genes belonging to disease resistance pathway as putative candidates for P. deltoides resistance to woolly poplar aphid. This work is the first report on genetic of woolly poplar aphid genetic resistance and the resistant loci associated markers identified represent a valuable tool in resistance poplar breeding programs. PMID:27022954

  15. Synergistic benefits of ionic liquid and alkaline pretreatments of poplar wood. Part 1: effect of integrated pretreatment on enzymatic hydrolysis.

    PubMed

    Yuan, Tong-Qi; Wang, Wei; Xu, Feng; Sun, Run-Cang

    2013-09-01

    An environmentally friendly pretreatment process was developed to fractionate hemicelluloses and lignin from poplar wood by ionic liquid (IL) pretreatment coupled with mild alkaline extraction. Hemicellulosic and lignin fractions were obtained in high yields, amounting to 59.3% and 74.4%, respectively, which can served as raw materials for production of value-added products. The yield of glucose for the integrated pretreated poplar wood was 99.2%, while it was just 19.2% for the untreated material. The synergistic benefits of the removal of lignin and hemicelluloses, the increase of the cellulose surface area, and the conversion of cellulose fibers from the cellulose I to the cellulose II crystal phase resulted in the high glucose yield for the integrated pretreated substrate. Therefore, the IL based biorefining strategy proposed can integrate biofuels production into a biorefinery scheme in which the major components of poplar wood can be converted into value-added products.

  16. Effects of a three-year exposure to ambient ozone on biomass allocation in poplar using ethylenediurea.

    PubMed

    Hoshika, Yasutomo; Pecori, Francesco; Conese, Ilaria; Bardelli, Tommaso; Marchi, Enrico; Manning, William J; Badea, Ovidiu; Paoletti, Elena

    2013-09-01

    We examined the effect of ambient ozone on visible foliar injury, growth and biomass in field-grown poplar cuttings of an Oxford clone sensitive to ozone (Populus maximoviczii Henry × berolinensis Dippel) irrigated with ethylenediurea (EDU) or water for three years. EDU is used as an ozone protectant for plants. Protective effects of EDU on ozone visible injury were found. As a result, poplar trees grown under EDU treatment increased leaves, lateral branches and root density in the third year, although no significant enhancement of stem height and diameter was found. Ambient ozone (AOT40, 24.6 ppm h; diurnal hourly average, 40.3 ppb) may finally reduce carbon gain by reducing the number of branches, and thus sites for leaf formation, in ozone-sensitive poplar trees under not-limiting conditions.

  17. Enhanced enzymatic hydrolysis of poplar bark by combined use of gamma ray and dilute acid for bioethanol production

    NASA Astrophysics Data System (ADS)

    Chung, Byung Yeoup; Lee, Jae Taek; Bai, Hyoung-Woo; Kim, Ung-Jin; Bae, Hyeun-Jong; Gon Wi, Seung; Cho, Jae-Young

    2012-08-01

    Pretreatment of poplar bark with a combination of sulfuric acid (3%, w/w, H2SO4) and gamma irradiation (0-1000 kGy) was performed in an attempt to enhance enzymatic hydrolysis for bioethanol production. The yields of reducing sugar were slightly increased with an increasing irradiation dose, ranging from 35.4% to 51.5%, with a 56.1% reducing sugar yield observed after dilute acid pretreatment. These results clearly showed that soluble sugars were released faster and to a greater extent in dilute acid-pretreated poplar bark than in gamma irradiation-pretreated bark. When combined pretreatment was carried out, a drastic increase in reducing sugar yield (83.1%) was found compared with individual pretreatment, indicating the possibility of increasing the convertibility of poplar bark following combined pretreatment. These findings are likely associated with cellulose crystallinity, lignin modification, and removal of hemicelluloses.

  18. Hydrologic data for the East Poplar oil field, Fort Peck Indian Reservation, Northeastern Montana

    USGS Publications Warehouse

    Thamke, J.N.; Craigg, S.D.; Mendes, T.M.

    1996-01-01

    This report presents selected hydrologic data for the East Poplar oil field, located in the south-central part of the Fort Peck Indian Reservation in northeastern Montana. Data about the occurrence, quantity, and quality of ground and surface water are presented in tabular form. The tables contain records of privately owned wells (active and abandoned), monitoring wells installed by the U.S. Geological Survey and Montana Bureau of Mines and Geology, oil wells, and brine-injection wells; lithologic descriptions of drill cuttings and well-completion data from monitoring wells; data from two aquifer tests conducted in Quaternary alluvial and glacial deposits; chemical quality of ground water; and information on the quantity and chemical quality of surface water. Records of electromagnetic geophysical measurements collected throughout an area of about 20 square miles of the study area are compiled and included on a floppy disk. Illustrations in this report contain information about study area location, site- numbering system, general physical and cultural features, and construction of monitoring wells installed by the U.S. Geological Survey. plate-sized map presents additional information about privately owned wells, monitoring wells, oil wells, brine-injections wells, surface-water data-collection sites, and area of electromagnetic data collection. The data presented in this report provide a base with which to better define and interpret the occurrence, quantity, and quality of ground and surface water in the vicinity of the Poplar River Valley in the south-central part of the Fort Peck Indian Reservation. The data can be used to help delineate the occurrence of brine and saline water in Quaternary alluvial and glacial deposits in the East Poplar oil field.

  19. The metagenome of an anaerobic microbial community decomposing poplar wood chips

    SciTech Connect

    van der Lelie D.; Taghavi, S.; McCorkle, S. M.; Li, L.-L.; Malfatti, S. A.; Monteleone, D.; Donohoe, B. S.; Ding, S.-Y.; Adney, W. S.; Himmel, M. E.; Tringe, S. G.

    2012-05-01

    This study describes the composition and metabolic potential of a lignocellulosic biomass degrading community that decays poplar wood chips under anaerobic conditions. We examined the community that developed on poplar biomass in a non-aerated bioreactor over the course of a year, with no microbial inoculation other than the naturally occurring organisms on the woody material. The composition of this community contrasts in important ways with biomass-degrading communities associated with higher organisms, which have evolved over millions of years into a symbiotic relationship. Both mammalian and insect hosts provide partial size reduction, chemical treatments (low or high pH environments), and complex enzymatic 'secretomes' that improve microbial access to cell wall polymers. We hypothesized that in order to efficiently degrade coarse untreated biomass, a spontaneously assembled free-living community must both employ alternative strategies, such as enzymatic lignin depolymerization, for accessing hemicellulose and cellulose and have a much broader metabolic potential than host-associated communities. This would suggest that such a community would make a valuable resource for finding new catalytic functions involved in biomass decomposition and gaining new insight into the poorly understood process of anaerobic lignin depolymerization. Therefore, in addition to determining the major players in this community, our work specifically aimed at identifying functions potentially involved in the depolymerization of cellulose, hemicelluloses, and lignin, and to assign specific roles to the prevalent community members in the collaborative process of biomass decomposition. A bacterium similar to Magnetospirillum was identified among the dominant community members, which could play a key role in the anaerobic breakdown of aromatic compounds. We suggest that these compounds are released from the lignin fraction in poplar hardwood during the decay process, which would point to

  20. Growth and physiological responses of isohydric and anisohydric poplars to drought

    PubMed Central

    Attia, Ziv; Domec, Jean-Christophe; Oren, Ram; Way, Danielle A.; Moshelion, Menachem

    2015-01-01

    Understanding how different plants prioritize carbon gain and drought vulnerability under a variable water supply is important for predicting which trees will maximize woody biomass production under different environmental conditions. Here, Populus balsamifera (BS, isohydric genotype), P. simonii (SI, previously uncharacterized stomatal behaviour), and their cross, P. balsamifera x simonii (BSxSI, anisohydric genotype) were studied to assess the physiological basis for biomass accumulation and water-use efficiency across a range of water availabilities. Under ample water, whole plant stomatal conductance (gs), transpiration (E), and growth rates were higher in anisohydric genotypes (SI and BSxSI) than in isohydric poplars (BS). Under drought, all genotypes regulated the leaf to stem water potential gradient via changes in gs, synchronizing leaf hydraulic conductance (Kleaf) and E: isohydric plants reduced Kleaf, gs, and E, whereas anisohydric genotypes maintained high Kleaf and E, which reduced both leaf and stem water potentials. Nevertheless, SI poplars reduced their plant hydraulic conductance (Kplant) during water stress and, unlike, BSxSI plants, recovered rapidly from drought. Low gs of the isohydric BS under drought reduced CO2 assimilation rates and biomass potential under moderate water stress. While anisohydric genotypes had the fastest growth under ample water and higher photosynthetic rates under increasing water stress, isohydric poplars had higher water-use efficiency. Overall, the results indicate three strategies for how closely related biomass species deal with water stress: survival-isohydric (BS), sensitive-anisohydric (BSxSI), and resilience-anisohydric (SI). Implications for woody biomass growth, water-use efficiency, and survival under variable environmental conditions are discussed. PMID:25954045

  1. VOC emissions of Grey poplar leaves as affected by salt stress and different N sources.

    PubMed

    Teuber, M; Zimmer, I; Kreuzwieser, J; Ache, P; Polle, A; Rennenberg, H; Schnitzler, J-P

    2008-01-01

    Nitrogen nutrition and salt stress experiments were performed in a greenhouse with hydroponic-cultured, salt-sensitive Grey poplar (Populus x canescens) plants to study the combined influence of different N sources (either 1 mm NO(3) (-) or NH(4)(+)) and salt (up to 75 mm NaCl) on leaf gas exchange, isoprene biosynthesis and VOC emissions. Net assimilation and transpiration proved to be highly sensitive to salt stress and were reduced by approximately 90% at leaf sodium concentrations higher than 1,800 microg Na g dry weight (dw)(-1). In contrast, emissions of isoprene and oxygenated VOC (i.e. acetaldehyde, formaldehyde and acetone) were unaffected. There was no significant effect of combinations of salt stress and N source, and neither NO(3)(-) or NH(4)(+) influenced the salt stress response in the Grey poplar leaves. Also, transcript levels of 1-deoxy-d-xylulose 5-phosphate reductoisomerase (PcDXR) and isoprene synthase (PcISPS) did not respond to the different N sources and only responded slightly to salt application, although isoprene synthase (PcISPS) activity was negatively affected at least in one of two experiments, despite high isoprene emission rates. A significant salt effect was the strong reduction of leaf dimethylallyl diphosphate (DMADP) content, probably due to restricted availability of photosynthates for DMADP biosynthesis. Further consequences of reduced photosynthetic gas exchange and maintaining VOC emissions are a very high C loss, up to 50%, from VOC emissions related to net CO(2) uptake and a strong increase in leaf internal isoprene concentrations, with maximum mean values up to 6.6 microl x l(-1). Why poplar leaves maintain VOC biosynthesis and emission under salt stress conditions, despite impaired photosynthetic CO(2) fixation, is discussed.

  2. Functional Characterization of Poplar Wood-Associated NAC Domain Transcription Factors1[C][OA

    PubMed Central

    Zhong, Ruiqin; Lee, Chanhui; Ye, Zheng-Hua

    2010-01-01

    Wood is the most abundant biomass produced by land plants. Dissection of the molecular mechanisms underlying the transcriptional regulation of wood formation is a fundamental issue in plant biology and has important implications in tree biotechnology. Although a number of transcription factors in tree species have been shown to be associated with wood formation and some of them are implicated in lignin biosynthesis, none of them have been demonstrated to be key regulators of the biosynthesis of all three major components of wood. In this report, we have identified a group of NAC domain transcription factors, PtrWNDs, that are preferentially expressed in developing wood of poplar (Populus trichocarpa). Expression of PtrWNDs in the Arabidopsis (Arabidopsis thaliana) snd1 nst1 double mutant effectively complemented the secondary wall defects in fibers, indicating that PtrWNDs are capable of activating the entire secondary wall biosynthetic program. Overexpression of PtrWND2B and PtrWND6B in Arabidopsis induced the expression of secondary wall-associated transcription factors and secondary wall biosynthetic genes and, concomitantly, the ectopic deposition of cellulose, xylan, and lignin. Furthermore, PtrWND2B and PtrWND6B were able to activate the promoter activities of a number of poplar wood-associated transcription factors and wood biosynthetic genes. Together, these results demonstrate that PtrWNDs are functional orthologs of SND1 and suggest that PtrWNDs together with their downstream transcription factors form a transcriptional network involved in the regulation of wood formation in poplar. PMID:19965968

  3. Analysis of the impact of biomechanical traits of European black Poplar on riverbank flow resistance

    NASA Astrophysics Data System (ADS)

    Battista Chirico, Giovanni; Saulino, Luigi; Pasquino, Vittorio; Villani, Paolo; Rita, Angelo; Todaro, Luigi; Saracino, Antonio

    2016-04-01

    Predicting the effects of riparian plants on river flow dynamics is fundamental for an appropriate river management. Riparian woody vegetation enhances bank cohesion and provides ecosystem services by mitigating nutrient and sediment loads to the river flow and enhancing biodiversity. However riparian trees also contribute to river flow resistance and thus can have a significant impact on flow dynamics during flood events. The flow-plant interaction mainly depends on plant morphological characters (e.g. diameter, height, canopy size, foliage density) and biomechanical properties, such as its flexural rigidity. This study aims at testing the hypothesis that the hydrodynamic behaviour of the European black Poplar (∖textit{Populus nigra} L.), a common woody riparian plant, is influenced by specific biomechanical traits developed as result of its adaptation to different river ecosystems. We examine the morphological and biomechanical properties of living stems of black Poplar sampled in two different riverine environments in Southern Italy located only a few kilometres apart. The two sample sets of living stems exhibit similar morphological traits but significantly different Young module of elasticity. We compared the drag forces that the flow would exert on these two different sets of plants for a wide range of flow velocities, by employing a numerical model that accounts for the bending behaviour of the woody plant due to the hydrodynamic load, under the hypothesis of complete submergence. A Monte Carlo approach was applied in order to account for the stochastic variability of the morphological and mechanical parameters affecting plant biomechanical behaviour. We identified a threshold value of the plant diameter, above which the two sets of European black Poplars are subjected to drag forces that differ by more than 25{∖%} on average, for flow velocities larger than 1 m/s.

  4. Intra-annual cambial activity and carbon availability in stem of poplar.

    PubMed

    Deslauriers, Annie; Giovannelli, Alessio; Rossi, Sergio; Castro, Gaetano; Fragnelli, Giuseppe; Traversi, Laura

    2009-10-01

    Cambial activity is influenced by many environmental and physiological factors and among them, carbon acts as a source of energy for the growing meristems. This work has focused on the intra-annual stem growth of poplar compared with the carbon available for xylogenesis processes in cambium and outer wood. The major stages of xylem production and differentiation in two poplar genotypes with different growth performances were considered. Monitoring of stem growth and leaf phenology combined with starch, nonstructural soluble sugars and water content in the stem was conducted from February to November 2006 in Populus x canadensis Moench 'I-214' and Populus deltoides Marsh. 'Dvina'. Anatomical analyses of wood formation were performed by measuring the width of the zones with differentiating and mature xylem. At the end of the growing period, wood density was assessed by microdensity analyses. Xylem differentiation at the top of the tree started at the beginning of April for both genotypes and proceeded down the stem at about 0.5 m day(-1), occurring almost at the same time as leaf opening. The rate of growth and wood density was superior in Dvina, but this higher productivity could not be explained by differences in the number of cambial initials and the duration of xylogenesis. However, the most productive poplar genotype showed higher glucose, fructose and sucrose content in the outer wood. The nonstructural soluble sugars available in the cambial zone followed the intra-annual pattern of xylem formation, with a higher concentration when the growth rate was maximum. The accumulations of nonstructural soluble sugars at a certain time during stem growth corresponded with a higher carbon availability to the actively growing meristems in the stem.

  5. Hybrid poplar plantations are suitable habitat for reintroduced forest herbs with conservation status.

    PubMed

    Boothroyd-Roberts, Kathleen; Gagnon, Daniel; Truax, Benoit

    2013-01-01

    Plantations of fast-growing tree species may be of use in conservation by accelerating the restoration of forest habitat on abandoned farmland and increasing connectivity in fragmented landscapes. The objective of this study was to determine if hybrid poplar plantations can be suitable habitats for the reintroduction of native forest plant species and, if so, which abiotic factors predict successful reintroduction. Four species of forest herb species (Trillium grandiflorum, Sanguinaria canadensis, Maianthemum racemosum, Asarum canadense), of which three have legal conservation status, were transplanted into experimental plantations of two hybrid poplar clones and nearby second-growth woodlots at six sites in southern Quebec, Canada. The transplanted individuals were protected from deer browsing with exclusion cages. After two years, the plant responses of all four species were stable or increased over two years in both types of hybrid poplar plantations. Sanguinaria showed a better response in the plantations than in the woodlots, preferring the rich post-agricultural soils of the plantations with low C:N ratios. Asarum and Maianthemum showed no significant difference between stand types, while Trillium grew better in the woodlots than in the plantations. Much of the variability in the response of the latter three species was unexplained by the measured environmental variables. These results suggest that certain forest herb species can be reintroduced as juvenile plants into plantations, knowing that their spontaneous recolonization is often limited by dispersal and/or seedling establishment. Plantations could also contribute to the conservation of biodiversity by providing an environment for the cultivation of forest herb species as an alternative to their destructive harvest from natural populations.

  6. Challenging synergistic activity of poplar-bacteria association for the Cd phytostabilization.

    PubMed

    C, Cocozza; D, Trupiano; G, Lustrato; G, Alfano; D, Vitullo; A, Falasca; T, Lomaglio; V, De Felice; G, Lima; G, Ranalli; S, Scippa; R, Tognetti

    2015-12-01

    The synergistic activity between plants and microorganisms may contribute to the implementation of proactive management strategies in the stabilization of contaminated sites, although heavy metals, such as cadmium (Cd), are potentially toxic to them. The aim of this study was to evaluate the degree of tolerance to Cd contamination (supplying twice 40 mg kg(-1) of Cd) in poplar cuttings [clone I-214, P. × euramericana (Dode) Guinier] inoculated or not with two concentrations of Serratia marcescens strain (1 × 10(7) CFU/g and 2 × 10(7) CFU/g of potting mix). The response of the plant-bacteria system to excess Cd was investigated with special reference to the structural traits of plants and the functional efficiency of bacteria. Bacterial colonization and substrate components were previously assessed in order to define the best solution for formulating the experimental plant growth media. The tested plant-bacteria association, especially when bacteria were provided in double concentration, stimulated specific tolerance mechanisms to Cd through the promotion of the poplar growth. Inoculated plants produced larger leaves and increased stem diameter, while roots grew longer and wider in Cd-treated plants. The effect of bacterial inoculum on plant growth traits and metal partitioning in plant organs was assessed in order to define the potential of this poplar clone to be a suitable candidate for phytostabilization of Cd-contaminated soil. The final effect of the inoculation with bacteria, which alleviated the metal load and Cd phytotoxicity due to their bioaccumulation ability, suggests promising phytostabilization potential of these plant-bacteria associations.

  7. The Metagenome of an Anaerobic Microbial Community Decomposing Poplar Wood Chips

    PubMed Central

    van der Lelie, Daniel; Taghavi, Safiyh; McCorkle, Sean M.; Li, Luen-Luen; Malfatti, Stephanie A.; Monteleone, Denise; Donohoe, Bryon S.; Ding, Shi-You; Adney, William S.; Himmel, Michael E.; Tringe, Susannah G.

    2012-01-01

    This study describes the composition and metabolic potential of a lignocellulosic biomass degrading community that decays poplar wood chips under anaerobic conditions. We examined the community that developed on poplar biomass in a non-aerated bioreactor over the course of a year, with no microbial inoculation other than the naturally occurring organisms on the woody material. The composition of this community contrasts in important ways with biomass-degrading communities associated with higher organisms, which have evolved over millions of years into a symbiotic relationship. Both mammalian and insect hosts provide partial size reduction, chemical treatments (low or high pH environments), and complex enzymatic ‘secretomes’ that improve microbial access to cell wall polymers. We hypothesized that in order to efficiently degrade coarse untreated biomass, a spontaneously assembled free-living community must both employ alternative strategies, such as enzymatic lignin depolymerization, for accessing hemicellulose and cellulose and have a much broader metabolic potential than host-associated communities. This would suggest that such a community would make a valuable resource for finding new catalytic functions involved in biomass decomposition and gaining new insight into the poorly understood process of anaerobic lignin depolymerization. Therefore, in addition to determining the major players in this community, our work specifically aimed at identifying functions potentially involved in the depolymerization of cellulose, hemicelluloses, and lignin, and to assign specific roles to the prevalent community members in the collaborative process of biomass decomposition. A bacterium similar to Magnetospirillum was identified among the dominant community members, which could play a key role in the anaerobic breakdown of aromatic compounds. We suggest that these compounds are released from the lignin fraction in poplar hardwood during the decay process, which would point

  8. Growth and physiological responses of isohydric and anisohydric poplars to drought

    DOE PAGES

    Attia, Ziv; Domec, Jean-Christophe; Oren, Ram; ...

    2015-05-07

    Understanding how different plants prioritize carbon gain and drought vulnerability under a variable water supply is important for predicting which trees will maximize woody biomass production under different environmental conditions. Here, Populus balsamifera (BS, isohydric genotype), P. simonii (SI, previously uncharacterized stomatal behaviour), and their cross, P. balsamifera x simonii (BSxSI, anisohydric genotype) were studied to assess the physiological basis for biomass accumulation and water-use efficiency across a range of water availabilities. Under ample water, whole plant stomatal conductance (gs), transpiration (E), and growth rates were higher in anisohydric genotypes (SI and BSxSI) than in isohydric poplars (BS). Under drought,more » all genotypes regulated the leaf to stem water potential gradient via changes in gs, synchronizing leaf hydraulic conductance (Kleaf) and E: isohydric plants reduced Kleaf, gs, and E, whereas anisohydric genotypes maintained high Kleaf and E, which reduced both leaf and stem water potentials. Nevertheless, SI poplars reduced their plant hydraulic conductance (Kplant) during water stress and, unlike, BSxSI plants, recovered rapidly from drought. Low gs of the isohydric BS under drought reduced CO2 assimilation rates and biomass potential under moderate water stress. While anisohydric genotypes had the fastest growth under ample water and higher photosynthetic rates under increasing water stress, isohydric poplars had higher water-use efficiency. Overall, the results indicate three strategies for how closely related biomass species deal with water stress: survival-isohydric (BS), sensitive-anisohydric (BSxSI), and resilience-anisohydric (SI). Lastly, we discuss implications for woody biomass growth, water-use efficiency, and survival under variable environmental conditions.« less

  9. Growth and physiological responses of isohydric and anisohydric poplars to drought

    SciTech Connect

    Attia, Ziv; Domec, Jean-Christophe; Oren, Ram; Way, Danielle A.; Moshelion, Menachem

    2015-05-07

    Understanding how different plants prioritize carbon gain and drought vulnerability under a variable water supply is important for predicting which trees will maximize woody biomass production under different environmental conditions. Here, Populus balsamifera (BS, isohydric genotype), P. simonii (SI, previously uncharacterized stomatal behaviour), and their cross, P. balsamifera x simonii (BSxSI, anisohydric genotype) were studied to assess the physiological basis for biomass accumulation and water-use efficiency across a range of water availabilities. Under ample water, whole plant stomatal conductance (gs), transpiration (E), and growth rates were higher in anisohydric genotypes (SI and BSxSI) than in isohydric poplars (BS). Under drought, all genotypes regulated the leaf to stem water potential gradient via changes in gs, synchronizing leaf hydraulic conductance (Kleaf) and E: isohydric plants reduced Kleaf, gs, and E, whereas anisohydric genotypes maintained high Kleaf and E, which reduced both leaf and stem water potentials. Nevertheless, SI poplars reduced their plant hydraulic conductance (Kplant) during water stress and, unlike, BSxSI plants, recovered rapidly from drought. Low gs of the isohydric BS under drought reduced CO2 assimilation rates and biomass potential under moderate water stress. While anisohydric genotypes had the fastest growth under ample water and higher photosynthetic rates under increasing water stress, isohydric poplars had higher water-use efficiency. Overall, the results indicate three strategies for how closely related biomass species deal with water stress: survival-isohydric (BS), sensitive-anisohydric (BSxSI), and resilience-anisohydric (SI). Lastly, we discuss implications for woody biomass growth, water-use efficiency, and survival under variable environmental conditions.

  10. Best management practices plan for the Lower East Fork Poplar Creek Operable Unit, Oak Ridge, Tennessee

    SciTech Connect

    1996-04-01

    This plan was prepared in support of the Phase II Remedial Design Report (DOE/OR/01-1449&D1) and in accordance with requirements under CERCLA to present the plan for best management practices to be followed during the remediation. This document provides the Environmental Restoration Program with information about spill prevention and control, water quality monitoring, good housekeeping practices, sediment and erosion control measures, and inspections and environmental compliance practices to be used during Phase II of the remediation project for the Lower East Fork Poplar Creek Operable Unit.

  11. Remedial investigation/feasibility study of the Clinch River/Poplar Creek operable unit. Volume 5

    SciTech Connect

    1996-03-01

    This volume is in support of the findings of an investigation into contamination of the Clinch River and Poplar Creek near the Oak Ridge Reservation (for more than 50 years, various hazardous and radioactive substances have been released to the environment as a result of operations and waste management activities there). It addresses the quality assurance objectives for measuring the data, presents selected historical data, contains data from several discrete water characterization studies, provides data supporting the sediment characterization, and contains data related to several biota characterization studies.

  12. Effect of lignin content on changes occurring in poplar cellulose ultrastructure during dilute acid pretreatment

    SciTech Connect

    Sun, Qining; Foston, Marcus; Meng, Xianzhi; Sawada, Daisuke; Pingali, Sai Venkatesh; O’Neill, Hugh M.; Li, Hongjia; Wyman, Charles E.; Langan, Paul; Ragauskas, Art J.; Kumar, Rajeev

    2014-10-14

    Obtaining a better understanding of the complex mechanisms occurring during lignocellulosic deconstruction is critical to the continued growth of renewable biofuel production. A key step in bioethanol production is thermochemical pretreatment to reduce plant cell wall recalcitrance for downstream processes. Previous studies of dilute acid pretreatment (DAP) have shown significant changes in cellulose ultrastructure that occur during pretreatment, but there is still a substantial knowledge gap with respect to the influence of lignin on these cellulose ultrastructural changes. This study was designed to assess how the presence of lignin influences DAP-induced changes in cellulose ultrastructure, which might ultimately have large implications with respect to enzymatic deconstruction efforts. Native, untreated hybrid poplar (Populus trichocarpa x Populus deltoids) samples and a partially delignified poplar sample (facilitated by acidic sodium chlorite pulping) were separately pretreated with dilute sulfuric acid (0.10 M) at 160°C for 15 minutes and 35 minutes, respectively . Following extensive characterization, the partially delignified biomass displayed more significant changes in cellulose ultrastructure following DAP than the native untreated biomass. With respect to the native untreated poplar, delignified poplar after DAP (in which approximately 40% lignin removal occurred) experienced: increased cellulose accessibility indicated by increased Simons’ stain (orange dye) adsorption from 21.8 to 72.5 mg/g, decreased cellulose weight-average degree of polymerization (DPw) from 3087 to 294 units, and increased cellulose crystallite size from 2.9 to 4.2 nm. These changes following DAP ultimately increased enzymatic sugar yield from 10 to 80%. We conclude that, overall, the results indicate a strong influence of lignin content on cellulose ultrastructural changes occurring during DAP. With the reduction of lignin content during DAP, the enlargement of

  13. Effect of lignin content on changes occurring in poplar cellulose ultrastructure during dilute acid pretreatment

    DOE PAGES

    Sun, Qining; Foston, Marcus; Meng, Xianzhi; ...

    2014-10-14

    Obtaining a better understanding of the complex mechanisms occurring during lignocellulosic deconstruction is critical to the continued growth of renewable biofuel production. A key step in bioethanol production is thermochemical pretreatment to reduce plant cell wall recalcitrance for downstream processes. Previous studies of dilute acid pretreatment (DAP) have shown significant changes in cellulose ultrastructure that occur during pretreatment, but there is still a substantial knowledge gap with respect to the influence of lignin on these cellulose ultrastructural changes. This study was designed to assess how the presence of lignin influences DAP-induced changes in cellulose ultrastructure, which might ultimately have largemore » implications with respect to enzymatic deconstruction efforts. Native, untreated hybrid poplar (Populus trichocarpa x Populus deltoids) samples and a partially delignified poplar sample (facilitated by acidic sodium chlorite pulping) were separately pretreated with dilute sulfuric acid (0.10 M) at 160°C for 15 minutes and 35 minutes, respectively . Following extensive characterization, the partially delignified biomass displayed more significant changes in cellulose ultrastructure following DAP than the native untreated biomass. With respect to the native untreated poplar, delignified poplar after DAP (in which approximately 40% lignin removal occurred) experienced: increased cellulose accessibility indicated by increased Simons’ stain (orange dye) adsorption from 21.8 to 72.5 mg/g, decreased cellulose weight-average degree of polymerization (DPw) from 3087 to 294 units, and increased cellulose crystallite size from 2.9 to 4.2 nm. These changes following DAP ultimately increased enzymatic sugar yield from 10 to 80%. We conclude that, overall, the results indicate a strong influence of lignin content on cellulose ultrastructural changes occurring during DAP. With the reduction of lignin content during DAP, the enlargement of

  14. Phasing Variants in Poplar Trees using a Hybrid of Short & Long Read Technologies

    SciTech Connect

    Schackwitz, Wendy; Martin, Joel; Lipzen, Anna; Pennacchio, Len; Tuskan, Gerald

    2013-03-26

    Poplar grow throughout the West coast & are adapted to extremely variable conditions. To examine what allows for this wide range of growth conditions, Jerry Tuskan's team has collected 1000 different individuals from British Columbia to California. In 2009, three Common Gardens were established where each individual was cloned in triplicate. Nearly all of these trees have been sequenced using short read technology, revealing a huge degree of variation in genotype. Correlating this genomic variation to phenotype would be greatly be strengthened if the variants could be phased into long haplotype blocks.

  15. Horizontal gene transfer to endogenous endophytic bacteria from poplar improves phytoremediation of toluene.

    PubMed

    Taghavi, Safiyh; Barac, Tanja; Greenberg, Bill; Borremans, Brigitte; Vangronsveld, Jaco; van der Lelie, Daniel

    2005-12-01

    Poplar, a plant species frequently used for phytoremediation of groundwater contaminated with organic solvents, was inoculated with the endophyte Burkholderia cepacia VM1468. This strain, whose natural host is yellow lupine, contains the pTOM-Bu61 plasmid coding for constitutively expressed toluene degradation. Noninoculated plants or plants inoculated with the soil bacterium B. cepacia Bu61(pTOM-Bu61) were used as controls. Inoculation of poplar had a positive effect on plant growth in the presence of toluene and reduced the amount of toluene released via evapotranspiration. These effects were more dramatic for VM1468, the endophytic strain, than for Bu61. Remarkably, none of the strains became established at detectable levels in the endophytic community, but there was horizontal gene transfer of pTOM-Bu61 to different members of the endogenous endophytic community, both in the presence and in the absence of toluene. This work is the first report of in planta horizontal gene transfer among plant-associated endophytic bacteria and demonstrates that such transfer could be used to change natural endophytic microbial communities in order to improve the remediation of environmental insults.

  16. Immunolocalization of phenylalanine ammonia-lyase and cinnamate-4-hydroxylase in differentiating xylem of poplar.

    PubMed

    Sato, Takahiko; Takabe, Keiji; Fujita, Minoru

    2004-01-01

    Phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) and cinnamate-4-hydroxylase (C4H; EC 1.14.13.11) are pivotal enzymes involved in lignification. We synthesized peptides as the epitopes according to the amino acid sequences of these enzymes, coupled them with hemocyanin, and injected them into mice. The antiserums against peptides of PAL and C4H specifically detected PAL and C4H in the crude enzymes extracted from differentiating xylem of poplar, respectively. PAL and C4H were localized in differentiating xylem of poplar. PAL labeling was mainly localized in the cytosol, and somewhat localized on the rough-endoplasmic reticulum (r-ER) and the Golgi apparatus. In contrast, C4H was mainly observed on r-ER and the Golgi apparatus. These findings suggest that conversion of phenylalanine to cinnamic acid occurs in the cytosol and the following reaction occurs near the membrane of r-ER and the Golgi apparatus. The possibility of coordinated localization of PAL and C4H is discussed.

  17. Interaction of drought and ozone exposure on isoprene emission from extensively cultivated poplar.

    PubMed

    Yuan, Xiangyang; Calatayud, Vicent; Gao, Feng; Fares, Silvano; Paoletti, Elena; Tian, Yuan; Feng, Zhaozhong

    2016-10-01

    The combined effects of ozone (O3 ) and drought on isoprene emission were studied for the first time. Young hybrid poplars (clone 546, Populus deltoides cv. 55/56 x P. deltoides cv. Imperial) were exposed to O3 (charcoal-filtered air, CF, and non-filtered air +40 ppb, E-O3 ) and soil water stress (well-watered, WW, and mild drought, MD, one-third irrigation) for 96 days. Consistent with light-saturated photosynthesis (Asat ), intercellular CO2 concentration (Ci ) and chlorophyll content, isoprene emission depended on drought, O3 , leaf position and sampling time. Drought stimulated emission (+38.4%), and O3 decreased it (-40.4%). Ozone increased the carbon cost per unit of isoprene emission. Ozone and drought effects were stronger in middle leaves (13th-15th from the apex) than in upper leaves (6th-8th). Only Asat showed a significant interaction between O3 and drought. When the responses were up-scaled to the entire-plant level, however, drought effects on total leaf area translated into around twice higher emission from WW plants in clean air than in E-O3 . Our results suggest that direct effects on plant emission rates and changes in total leaf area may affect isoprene emission from intensively cultivated hybrid poplar under combined MD and O3 exposure, with important feedbacks for air quality.

  18. Fuzzy-logic modeling of land suitability for hybrid poplar across the Prairie Provinces of Canada.

    PubMed

    Joss, B N; Hall, R J; Sidders, D M; Keddy, T J

    2008-06-01

    Determining the feasibility of a large-scale afforestation program is one approach being investigated by the Government of Canada to increase Canada's potential to sequester carbon from the atmosphere. Large-scale afforestation, however, requires knowledge of where it is suitable to establish and grow trees. Spatial models based on Boolean logic and/or statistical models within a geographic information system may be used for this purpose, but empirical environmental data are often lacking, and the association of these data to land suitability is most often a subjective process. As a solution to this problem, this paper presents a fuzzy-logic modeling approach to assess land suitability for afforestation of hybrid poplar (Populus spp.) over the Prairie Provinces of Canada. Expert knowledge regarding the selection and magnitudes of environmental variables were integrated into fuzzy rule sets from which estimates of land suitability were generated and presented in map form. The environmental variables selected included growing season precipitation, climate moisture index, growing degree days, and Canada Land Inventory capability for agriculture and elevation. Approximately 150,000 km2, or 28% of the eligible land base within the Prairie Provinces was found to be suitable for afforestation. Accuracy assessments conducted with fuzzy accuracy methods provided a more descriptive assessment of the resulting land suitability map than figures generated from a more conventional Boolean-based accuracy measure. Modeling, mapping and accuracy assessment issues were identified for future extension of this work to map hybrid poplar land suitability over Canada.

  19. Non-destructive Analysis Chlorophyll Content of Different Genotypes of Poplars Based on Hyperspectral Reflectance Data

    NASA Astrophysics Data System (ADS)

    Jin, S.; Dian, Y.; Wang, R.; Peng, L.; Liu, X.; Zhou, Z.; Zhong, S.; Wang, Y.

    2016-11-01

    Leaf Chlorophyll content (Ct) indicates plant physiological status and can be detected by hyperspectral measurements. However, it is difficult to conclude that different genotypes of same species have the same relationship with the hyperspectral data. The aim of this paper was to test that whether the different genotypes of same species have the similar relationship with hyperspectral reflectance. First of all, spectral reflectance of populus simonii (Populus simonii Carr) and I-72 poplar (Populus euramericana cv. ‘San Martino I-72/58’) were collected by spectrometric meter, and then extract chlorophyll index (CI) and other 11 types of vegetation indices from the hyperspectral reflectance data. At last, relationships between different vegetation indices and Ct of the two genotypes of poplar were compared. Results show that (1) the relationships between SPAD value and Ct are different in the low and high Ct level, we can choose proper vegetation index, REPIG, mSR705 and SDr/SDb et al to predict the Ct value. (2) Meanwhile, we can use PSSRb and PRI to distinguish fine difference between different genotypes.

  20. Canopy profiles of photosynthetic parameters under elevated CO2 and N fertilization in a poplar plantation.

    PubMed

    Calfapietra, Carlo; Tulva, Ingmar; Eensalu, Eve; Perez, Marta; De Angelis, Paolo; Scarascia-Mugnozza, Giuseppe; Kull, Olevi

    2005-10-01

    A poplar plantation has been exposed to an elevated CO2 concentration for 5 years using the free air CO2 enrichment (FACE) technique. Even after such a long period of exposure, leaves of Populus x euramericana have not shown clear signs of photosynthetic acclimation. Only at the end of the growing season for shade leaves was a decrease of maximum velocity of carboxylation (Vcmax) observed. Maximum electron transport rate (Jmax) was increased by FACE treatment in July. Assimilation rates at CO2 partial pressure of 400 (A400) and 600 (A600) micromol mol(-1) were not significantly different under FACE treatment. Most notably FACE significantly decreased stomatal conductance (g(s)) both on upper and lower canopy leaves. N fertilization increased N content in the leaves on mass basis (Nm) and specific leaf area (SLA) in both CO2 treatments but did not influence the photosynthetic parameters. These data show that in poplar plantations the long-term effects of elevated CO2 on photosynthesis do not differ considerably from the short-term ones even with N deposition.

  1. Engineering Monolignol p-Coumarate Conjugates into Poplar and Arabidopsis Lignins.

    PubMed

    Smith, Rebecca A; Gonzales-Vigil, Eliana; Karlen, Steven D; Park, Ji-Young; Lu, Fachuang; Wilkerson, Curtis G; Samuels, Lacey; Ralph, John; Mansfield, Shawn D

    2015-12-01

    Lignin acylation, the decoration of hydroxyls on lignin structural units with acyl groups, is common in many plant species. Monocot lignins are decorated with p-coumarates by the polymerization of monolignol p-coumarate conjugates. The acyltransferase involved in the formation of these conjugates has been identified in a number of model monocot species, but the effect of monolignol p-coumarate conjugates on lignification and plant growth and development has not yet been examined in plants that do not inherently possess p-coumarates on their lignins. The rice (Oryza sativa) p-COUMAROYL-Coenzyme A MONOLIGNOL TRANSFERASE gene was introduced into two eudicots, Arabidopsis (Arabidopsis thaliana) and poplar (Populus alba × grandidentata), and a series of analytical methods was used to show the incorporation of the ensuing monolignol p-coumarate conjugates into the lignin of these plants. In poplar, specifically, the addition of these conjugates did not occur at the expense of the naturally incorporated monolignol p-hydroxybenzoates. Plants expressing the p-COUMAROYL-Coenzyme A MONOLIGNOL TRANSFERASE transgene can therefore produce monolignol p-coumarate conjugates essentially without competing with the formation of other acylated monolignols and without drastically impacting normal monolignol production.

  2. Tulip-poplar leaf diffusion resistance calculated from stomatal dimensions and varying environmental parameters

    SciTech Connect

    McConathy, R.K.

    1983-03-01

    The study describes the gradients of stomatal size and density in the crown of a mature forest-grown tulip-poplar (Liriodendron tulipifera L.) in eastern Tennessee. These data are used to predict leaf resistance to vapor diffusion in relation to stomatal width and boundary layer resistance. Stomatal density on individual leaves did not vary, but density increased with increasing crown height. Stomatal size decreased with increasing height of leaves within the crown. Stomatal size and density variations interacted to result in a constant number of stomata per leaf at all crown heights. Stomatal diffusive resistance values calculated from stomatal measurements and varying environmental parameters indicated that stomatal resistance controlled transpiration water losses only at small apertures (<0.6 ..mu..m). Boundary layer resistance was controlling at large stomatal apertures (>0.6 ..mu..m) and at low wind speeds (approx.100 cm/s). Under normal forest conditions tulip-poplar stomatal resistance exercised more control over transpiration than did boundary layer resistance.

  3. Ozone exposure and flux-based response functions for photosynthetic traits in wheat, maize and poplar.

    PubMed

    Bagard, Matthieu; Jolivet, Yves; Hasenfratz-Sauder, Marie-Paule; Gérard, Joëlle; Dizengremel, Pierre; Le Thiec, Didier

    2015-11-01

    Ozone exposure- and dose-response relationships based on photosynthetic leaf traits (CO2 assimilation, chlorophyll content, Rubisco and PEPc activities) were established for wheat, maize and poplar plants grown in identical controlled conditions, providing a comparison between crop and tree species, as well as between C3 and C4 plants. Intra-specific variability was addressed by comparing two wheat cultivars with contrasting ozone tolerance. Depending on plant models and ozone levels, first-order, second-order and segmented linear regression models were used to derive ozone response functions. Overall, flux-based functions appeared superior to exposure-based functions in describing the data, but the improvement remained modest. The best fit was obtained using the POD0.5 for maize and POD3 for poplar. The POD6 appeared relevant for wheat, although intervarietal differences were found. Our results suggest that taking into account the dynamics of leaf antioxidant capacity could improve current methods for ozone risk assessment for plants.

  4. Enhanced bioethanol production from yellow poplar by deacetylation and oxalic acid pretreatment without detoxification.

    PubMed

    Kundu, Chandan; Lee, Hong-Joo; Lee, Jae-Won

    2015-02-01

    In order to produce ethanol from yellow poplar, deacetylation was performed using sodium hydroxide (NaOH). Optimal deacetylation conditions were determined by a response surface methodology. The highest acetic acid concentration obtained was 7.06 g/L when deacetylation was performed at 60 °C for 80 min with 0.8% NaOH. Acetic acid was recovered by electrodialysis from the deacetylated hydrolysate. The oxalic acid pretreatment of deacetylated biomass was carried out and the hydrolysate directly used for ethanol production without detoxification. Ethanol yields ranged from 0.34 to 0.47 g/g and the highest ethanol yield was obtained when pretreatment was carried out at 150 °C with 50 mM oxalic acid. The highest ethanol concentration obtained from pretreated biomass was 27.21 g/L at 170 °C, using a 50 mM of oxalic acid for the simultaneous saccharification and fermentation (SSF). Overall, 20.31 g of ethanol was obtained by hydrolysate and SSF from 100 g of deacetylated yellow poplar.

  5. Engineering Monolignol p-Coumarate Conjugates into Poplar and Arabidopsis Lignins1

    PubMed Central

    Smith, Rebecca A.; Gonzales-Vigil, Eliana; Karlen, Steven D.; Park, Ji-Young; Lu, Fachuang; Wilkerson, Curtis G.; Samuels, Lacey; Ralph, John; Mansfield, Shawn D.

    2015-01-01

    Lignin acylation, the decoration of hydroxyls on lignin structural units with acyl groups, is common in many plant species. Monocot lignins are decorated with p-coumarates by the polymerization of monolignol p-coumarate conjugates. The acyltransferase involved in the formation of these conjugates has been identified in a number of model monocot species, but the effect of monolignol p-coumarate conjugates on lignification and plant growth and development has not yet been examined in plants that do not inherently possess p-coumarates on their lignins. The rice (Oryza sativa) p-COUMAROYL-Coenzyme A MONOLIGNOL TRANSFERASE gene was introduced into two eudicots, Arabidopsis (Arabidopsis thaliana) and poplar (Populus alba × grandidentata), and a series of analytical methods was used to show the incorporation of the ensuing monolignol p-coumarate conjugates into the lignin of these plants. In poplar, specifically, the addition of these conjugates did not occur at the expense of the naturally incorporated monolignol p-hydroxybenzoates. Plants expressing the p-COUMAROYL-Coenzyme A MONOLIGNOL TRANSFERASE transgene can therefore produce monolignol p-coumarate conjugates essentially without competing with the formation of other acylated monolignols and without drastically impacting normal monolignol production. PMID:26511914

  6. Genome-scale transcriptome analysis of the desert poplar, Populus euphratica.

    PubMed

    Qiu, Qiang; Ma, Tao; Hu, Quanjun; Liu, Bingbing; Wu, Yuxia; Zhou, Haihong; Wang, Qian; Wang, Juan; Liu, Jianquan

    2011-04-01

    Populus euphratica is well-adapted to extreme desert environments and is an important model species for studying the effects of abiotic stresses on trees. Here we present the first deep transcriptomic analysis of this species. To maximize representation of conditional transcripts, mRNA was obtained from living tissues of desert-grown trees and two types of callus (salt-stressed and unstressed). De novo assembly generated 86,777 Unigenes using Solexa sequence data. These sequences covered 92% of previously reported P. euphratica expressed sequence tags (ESTs) and 90% of the TIGR poplar ESTs, and a total of 58,499 high-quality unique sequences were annotated by BLAST similarity searches against public databases. We found that 27% of the total Unigenes were differentially expressed (up- or down-regulated) in response to salt stress in P. euphratica callus. These differentially expressed genes are mainly involved in transport, transcription, cellular communication and metabolism. In addition, we found that numerous putative genes involved in ABA regulation and biosynthesis were also differentially regulated. This study represents the deepest transcriptomic and gene-annotation analysis of P. euphratica to date. The genetic knowledge acquired should be very useful for future studies of the molecular adaptation of this tree species to abiotic stress and facilitate genetic manipulation of other poplar species.

  7. Association genetics of chemical wood properties in black poplar (Populus nigra).

    PubMed

    Guerra, Fernando P; Wegrzyn, Jill L; Sykes, Robert; Davis, Mark F; Stanton, Brian J; Neale, David B

    2013-01-01

    Black poplar (Populus nigra) is a potential feedstock for cellulosic ethanol production, although breeding for this specific end use is required. Our goal was to identify associations between single nucleotide polymorphism (SNP) markers within candidate genes encoding cellulose and lignin biosynthetic enzymes, with chemical wood property phenotypic traits, toward the aim of developing genomics-based breeding technologies for bioethanol production. Pyrolysis molecular beam mass spectrometry was used to determine contents of five- and six-carbon sugars, lignin, and syringyl : guaiacyl ratio. The association population included 599 clones from 17 half-sib families, which were successfully genotyped using 433 SNPs from 39 candidate genes. Statistical analyses were performed to estimate genetic parameters, linkage disequilibrium (LD), and single marker and haplotype-based associations. A moderate to high heritability was observed for all traits. The LD, across all candidate genes, showed a rapid decay with physical distance. Analysis of single marker-phenotype associations identified six significant marker-trait pairs, whereas nearly 280 haplotypes were associated with phenotypic traits, in both an individual and multiple trait-specific manner. The rapid decay of LD within candidate genes in this population and the genetic associations identified suggest a close relationship between the associated SNPs and the causative polymorphisms underlying the genetic variation of lignocellulosic traits in black poplar.

  8. Local selection across a latitudinal gradient shapes nucleotide diversity in balsam poplar, Populus balsamifera L.

    PubMed

    Keller, Stephen R; Levsen, Nicholas; Ingvarsson, Pär K; Olson, Matthew S; Tiffin, Peter

    2011-08-01

    Molecular studies of adaptive evolution often focus on detecting selective sweeps driven by positive selection on a species-wide scale; however, much adaptation is local, particularly of ecologically important traits. Here, we look for evidence of range-wide and local adaptation at candidate genes for adaptive phenology in balsam poplar, Populus balsamifera, a widespread forest tree whose range extends across environmental gradients of photoperiod and growing season length. We examined nucleotide diversity of 27 poplar homologs of the flowering-time network-a group of genes that control plant developmental phenology through interactions with environmental cues such as photoperiod and temperature. Only one gene, ZTL2, showed evidence of reduced diversity and an excess of fixed replacement sites, consistent with a species-wide selective sweep. Two other genes, LFY and FRI, harbored high levels of nucleotide diversity and exhibited elevated differentiation between northern and southern accessions, suggesting local adaptation along a latitudinal gradient. Interestingly, FRI has also been identified as a target of local selection between northern and southern accessions of Arabidopsis thaliana, indicating that this gene may be commonly involved in ecological adaptation in distantly related species. Our findings suggest an important role for local selection shaping molecular diversity and reveal limitations of inferring molecular adaptation from analyses designed only to detect species-wide selective sweeps.

  9. An investigation of shallow ground-water quality near East Fork Poplar Creek, Oak Ridge, Tennessee

    USGS Publications Warehouse

    Carmichael, J.K.

    1989-01-01

    Alluvial soils of the flood plain of East Fork Poplar Creek in Oak Ridge, Tennessee, are contaminated with mercury and other metals, organic compounds, and radio-nuclides originating from the Y-12 Plant, a nuclear-processing facility located within the U.S. Department of Energy 's Oak Ridge Reservation. Observation wells were installed in the shallow aquifer of the flood plain, and water quality samples were collected to determine if contaminants are present in the shallow groundwater. Groundwater in the shallow aquifer occurs under water-table conditions. Recharge is primarily from precipitation and discharge is to East Fork Poplar Creek. Groundwater levels fluctuate seasonally in response to variations in recharge and evapotranspiration. During extremely dry periods, the water table drops below the base of the shallow aquifer in some flood-plain areas. Contaminants found in water samples from several of the wells in concentrations which equaled or exceeded drinking-water standards established by the U.S. Environmental Protection Agency are antimony, chromium, lead, mercury, selenium, phenols, and strontium-90. Total and dissolved uranium concentrations exceeded the analytical detection limit in nearly 70% of the wells in the flood plain. The results of water quality determinations demonstrate that elevated concentrations of most trace metals (and possibly organic compounds and radionuclides) were caused by contaminated sediments in the samples. The presence of contaminated sediment in samples is suspected to be the result of borehole contamination during well installation. (USGS)

  10. Tryptamine-induced resistance in tryptophan decarboxylase transgenic poplar and tobacco plants against their specific herbivores.

    PubMed

    Gill, Rishi I S; Ellis, Brian E; Isman, Murray B

    2003-04-01

    The presence of amines and their derivatives in plant tissues is known to influence insect feeding and reproduction. The enzyme tryptophan decarboxylase (TDC) catalyzes the decarboxylation of tryptophan to tryptamine, which is both a bioactive amine and a precursor of other indole derivatives. Transgenic poplar and tobacco plants ectopically expressing TDC1 accumulated elevated levels of tryptamine without affecting plant growth and development. This accumulation was consistently associated with adverse effects on feeding behavior and physiology of Malacosoma disstria Hub. (forest tent caterpillar, FTC) and Manduca sexta L. (tobacco hornworm, THW). Behavior studies with FTC and THW larvae showed that acceptability of the leaf tissue to larvae was inversely related to foliar tryptamine levels. Physiological studies with FTC and THW larvae showed that consumption of leaf tissue from the transgenic lines is deleterious to larvae growth, apparently due to a postingestive mechanism. Thus, ectopic expression of TDC1 can allow sufficient tryptamine to accumulate in poplar and tobacco leaf tissue to suppress significantly the growth of insect pests that normally feed on these plants.

  11. The Oak Ridge Y-12 Plant biological monitoring and abatement program for East Fork Poplar Creek

    SciTech Connect

    Loar, J.M.; Adams, S.M.; Allison, L.J.; Giddings, J.M.; McCarthy, J.F.; Southworth, G.R.; Smith, J.G.; Stewart, A.J.; Springborn Bionomics, Inc., Wareham, MA; Oak Ridge National Lab., TN )

    1989-10-01

    In May 1985, a National Pollutant Discharge Elimination System permit was issued for the Oak Ridge Y-12 Plant, a nuclear weapons components production facility located in Oak Ridge, Tennessee, and operated by Martin Marietta Energy Systems, Inc., for the US Department of Energy. As a condition of the permit, a Biological Monitoring and Abatement Program (BMAP) was developed to demonstrate that the effluent limitations established for the Oak Ridge Y-12 Plant protect the classified uses of the receiving stream (East Fork Poplar Creek), in particular, the growth and propagation of fish and aquatic life, as designated by the Tennessee Department of Health and Environment. A second purpose for the BMAP is to document the ecological effects resulting from implementation of a water pollution control program that will include construction of nine new wastewater treatment facilities over the next 4 years. Because of the complex nature of the effluent discharged to East Fork Poplar Creek and the temporal and spatial variability in the composition of the effluent (i.e., temporal variability related to various pollution abatement measures that will be implemented over the next several years and spatial variability caused by pollutant inputs downstream of the Oak Ridge Y-12 Plant), a comprehensive, integrated approach to biological monitoring was developed for the BMAP. 39 refs., 5 figs., 8 tabs.

  12. Epigenetic control of heavy metal stress response in mycorrhizal versus non-mycorrhizal poplar plants.

    PubMed

    Cicatelli, Angela; Todeschini, Valeria; Lingua, Guido; Biondi, Stefania; Torrigiani, Patrizia; Castiglione, Stefano

    2014-02-01

    It was previously shown that arbuscular mycorrhizal fungi (AMF) exert a significant improvement of growth in a tolerant white poplar (Populus alba L.) clone (AL35) grown on Cu- and Zn-polluted soil via foliar alterations in the levels of defence/stress-related transcripts and molecules. However, nothing is known about the epigenetic changes which occur during tolerance acquisition in response to heavy metals (HMs) in the same mycorrhizal vs. non-mycorrhizal poplar plants. In order to analyse the epigenome in leaves of AL35 plants inoculated or not with AMF and grown in a greenhouse on multimetal polluted or unpolluted soil, the Methylation Sensitive Amplification Polymorphism (MSAP) approach was adopted to detect cytosine DNA methylation. Modest changes in cytosine methylation patterns were detected at first sampling (4 months from planting), whereas extensive alterations (hypomethylation) occurred at second sampling (after 6 months) in mycorrhizal plants grown in the presence of HMs. The sequencing of MSAP fragments led to the identification of genes belonging to several Gene Ontology categories. Seven MSAP fragments, selected on the basis of DNA methylation status in treated vs control AL35 leaves at the end of the experiment, were analysed for their transcript levels by means of qRT-PCR. Gene expression varied in treated samples relative to controls in response to HMs and/or AMF inoculation; in particular, transcripts of genes involved in RNA processing, cell wall and amino acid metabolism were upregulated in the presence of AMF with or without HMs.

  13. Modification of Lignin by Protein Cross-linking to Facilitate Production of Biofuels From Poplar

    SciTech Connect

    Tien, Ming

    2013-04-22

    The limited supply of fossil fuels and the associated environmental issues associated with their utilization has resulted in much effort put forth to promote renewable resources of energy. Switching to renewable fuels for energy will allow us to become carbon neutral by recycling carbon from plants and reduce carbon from dioxide emissions, which could potentially reduce global warming in future generations and generate new industries with exciting new technologies.

  14. Borehole geophysical data for the East Poplar oil field area, Fort Peck Indian Reservation, northeastern Montana, 1993, 2004, and 2005

    USGS Publications Warehouse

    Smith, Bruce D.; Thamke, Joanna N.; Tyrrell, Christa

    2014-01-01

    Areas of high electrical conductivity in shallow aquifers in the East Poplar oil field area were delineated by the U.S. Geological Survey (USGS), in cooperation with the Fort Peck Assiniboine and Sioux Tribes, in order to interpret areas of saline-water contamination. Ground, airborne, and borehole geophysical data were collected in the East Poplar oil field area from 1992 through 2005 as part of this delineation. This report presents borehole geophysical data for thirty-two wells that were collected during, 1993, 2004, and 2005 in the East Poplar oil field study area. Natural-gamma and induction instruments were used to provide information about the lithology and conductivity of the soil, rock, and water matrix adjacent to and within the wells. The well logs were also collected to provide subsurface controls for interpretation of a helicopter electromagnetic survey flown over most of the East Poplar oil field in 2004. The objective of the USGS studies was to improve understanding of aquifer hydrogeology particularly in regard to variations in water quality.

  15. Down-regulation of GIGANTEA-like genes increases plant growth and salt stress tolerance in poplar.

    PubMed

    Ke, Qingbo; Kim, Ho Soo; Wang, Zhi; Ji, Chang Yoon; Jeong, Jae Cheol; Lee, Haeng-Soon; Choi, Young-Im; Xu, Bingcheng; Deng, Xiping; Yun, Dae-Jin; Kwak, Sang-Soo

    2017-03-01

    The flowering time regulator GIGANTEA (GI) connects networks involved in developmental stage transitions and environmental stress responses in Arabidopsis. However, little is known about the role of GI in growth, development and responses to environmental challenges in the perennial plant poplar. Here, we identified and functionally characterized three GI-like genes (PagGIa, PagGIb and PagGIc) from poplar (Populus alba × Populus glandulosa). PagGIs are predominantly nuclear localized and their transcripts are rhythmically expressed, with a peak around zeitgeber time 12 under long-day conditions. Overexpressing PagGIs in wild-type (WT) Arabidopsis induced early flowering and salt sensitivity, while overexpressing PagGIs in the gi-2 mutant completely or partially rescued its delayed flowering and enhanced salt tolerance phenotypes. Furthermore, the PagGIs-PagSOS2 complexes inhibited PagSOS2-regulated phosphorylation of PagSOS1 in the absence of stress, whereas these inhibitions were eliminated due to the degradation of PagGIs under salt stress. Down-regulation of PagGIs by RNA interference led to vigorous growth, higher biomass and enhanced salt stress tolerance in transgenic poplar plants. Taken together, these results indicate that several functions of Arabidopsis GI are conserved in its poplar orthologues, and they lay the foundation for developing new approaches to producing salt-tolerant trees for sustainable development on marginal lands worldwide.

  16. Identification of 4CL Genes in Desert Poplars and Their Changes in Expression in Response to Salt Stress.

    PubMed

    Zhang, Cai-Hua; Ma, Tao; Luo, Wen-Chun; Xu, Jian-Mei; Liu, Jian-Quan; Wan, Dong-Shi

    2015-09-18

    4-Coumarate:CoA ligase (4CL) genes are critical for the biosynthesis of plant phenylpropanoids. Here we identified 20 4CL genes in the genomes of two desert poplars (Populus euphratica and P. pruinosa) and salt-sensitive congener (P. trichocarpa), but 12 in Salix suchowensis (Salix willow). Phylogenetic analyses clustered all Salicaceae 4CL genes into two clades, and one of them (corresponding to the 4CL-like clade from Arabidopsis) showed signals of adaptive evolution, with more genes retained in Populus than Salix and Arabidopsis. We also found that 4CL12 (in 4CL-like clade) showed positive selection along the two desert poplar lineages. Transcriptional profiling analyses indicated that the expression of 4CL2, 4CL11, and 4CL12 changed significantly in one or both desert poplars in response to salt stress compared to that of in P. trichocarpa. Our results suggest that the evolution of the 4CL genes may have contributed to the development of salt tolerance in the two desert poplars.

  17. Bt-Cry3Aa expression reduces insect damage and improves growth in field-grown hybrid poplar

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated growth and insect resistance in hybrid poplar expressing the cry3Aa gene in two field trials. An initial screening of 502 trees comprising 51 transgenic gene insertion events in four clonal backgrounds (Populus trichocarpa x P. deltoides, clones 24-305, 50-197, and 198-434; and P. d...

  18. Efficient Agrobacterium-mediated transformation of commercial hybrid poplar Populus nigra L. x P. maximowiczii A. Henry.

    PubMed

    Yevtushenko, Dmytro P; Misra, Santosh

    2010-03-01

    Many economically important species of Populus, especially those in sections Aigeiros and Tacamahaca, remain recalcitrant to genetic transformation. In this study, a simple and reliable protocol was developed for the efficient Agrobacterium-mediated transformation of a difficult-to-transform, but commercially viable, hybrid poplar Populus nigra L. x P. maximowiczii A. Henry (NM6). A plant transformation vector designed to express the beta-glucuronidase (GUS) gene was used to detect transformation events at early stages of plant regeneration and to optimize parameters affecting poplar transformation. The use of zeatin riboside in shoot-induction medium, regeneration of shoots via indirect organogenesis, and early selection pressure were the major modifications that drastically improved the efficiency of poplar transformation and minimized the number of untransformed regenerants. Transgenic shoots were routinely obtained 4-10 weeks after co-culture with A. tumefaciens, with a greater than 90% rate of plant recovery. Stable transgene integration, ranging from a single insertion to ten copies per genome, was confirmed by Southern blot analysis. The mean transformation frequency was 36.3% and about two-thirds of the lines had 1-2 transgene copies. Among the explants, petioles and leaves had a higher transformation frequency than did stem segments. Growth characteristics and the morphology of transgenic poplar plants were identical to untransformed controls. These findings will accelerate the development of P. nigra x P. maximowiczii plants with novel traits, and may also be useful to improve transformation procedures for other Populus species.

  19. Root hydraulic properties and growth of balsam poplar (Populus balsamifera) mycorrhizal with Hebeloma crustuliniforme and Wilcoxina mikolae var. mikolae.

    PubMed

    Siemens, J Aurea; Zwiazek, Janusz J

    2008-10-01

    The effects of an E-strain fungus (Wilcoxina mikolae var. mikolae) and an ectomycorrhizal fungus (Hebeloma crustuliniforme) on growth and water relations of balsam poplar were examined and compared in the present study. Balsam poplar roots inoculated with W. mikolae var. mikolae (Wm) exhibited structures consistent with ectendomycorrhizal (EEM) associations, including a mantle surrounding the outside of the root and an extensive Hartig net that was located between cortical cells and extended to the vascular cylinder. Roots colonized with H. crustuliniforme (Hc) developed a mantle layer, indicative of an ectomycorrhizal (ECM) association, around the outer part of the root, but no distinct Hartig net was present. Wm-colonized balsam poplar also showed increased shoot growth, stomatal conductance (g(s)), and root volumes compared with non-inoculated and Hc-inoculated plants. However, Hc-inoculated plants had higher root hydraulic conductivity (L(pr)) compared with non-inoculated plants and Wm-inoculated plants. These results suggest that L(pr) was not a growth-limiting factor in balsam poplar and that hyphal penetration of the root cortex in itself may have little influence on root hydraulic properties.

  20. [Seasonal dynamics of quantitative and morphological traits of poplar fine roots and their differences between successive rotation plantations].

    PubMed

    Wang, Yan-ping; Xu, Tan; Zhu, Wan-rui; Wang, Qi-tong; Liu, Meng-ling; Wang, Hua-tian; Li, Chuan-rong; Dong, Yu-feng

    2016-02-01

    Based on the fine root samples of the first and second generations of poplar (Populus x euramericana ' Neva'), this study examined the response of quantitative and morphological traits of fine roots of different orders and the difference between generations. The results showed that, the quantitative traits of fine roots, such as root length, root surface area and root biomass, presented obvious seasonal variation, and the fine root traits had obvious difference among root orders. The quantitative traits of lower-order fine roots showed significant seasonal difference, and the fine root biomass increased in the growing season and then decreased significantly. The specific root length (SRL) of higher-order roots also showed significant change with season, while the root length density (RLD) and root tissue density (RTD) changed a little. The successive rotation resulted in the significant increase of root length, root biomass, SRL and RLD of 1-2 orders in the growing season. The quantitative traits of first order root significantly positively correlated with soil temperature and moisture, and significantly negatively correlated with the soil organic matter and soil available nitrogen content. However, the quantitative traits of second order root only showed significant correlation with soil nutrient content. The seasonal dynamics of poplar fine roots and the difference between successive rotation plantations implied carbon investment change of poplar to roots. Soil nutrient deficiency induced more carbon investment into roots, and this carbon allocation pattern might affect the aboveground productivity of poplar plantation.

  1. Transgenic poplar trees expressing yeast cadmium factor 1 exhibit the characteristics necessary for the phytoremediation of mine tailing soil.

    PubMed

    Shim, Donghwan; Kim, Sangwoo; Choi, Young-Im; Song, Won-Yong; Park, Jiyoung; Youk, Eun Soo; Jeong, Soon-Chun; Martinoia, Enrico; Noh, Eun-Woon; Lee, Youngsook

    2013-01-01

    Genetic engineering of plants for phytoremediation is thought to be possible based on results using model plants expressing genes involved in heavy metal resistance, which improve the plant's tolerance of heavy metals and accumulation capacity. The next step of progress in this technology requires the genetic engineering of plants that produce large amounts of biomass and the testing of these transgenic plants in contaminated soils. Thus, we transformed a sterile line of poplar Populus alba X P. tremula var. glandulosa with a heavy metal resistance gene, ScYCF1 (yeast cadmium factor 1), which encodes a transporter that sequesters toxic metal(loid)s into the vacuoles of budding yeast, and tested these transgenic plants in soil taken from a closed mine site contaminated with multiple toxic metal(loid)s under greenhouse and field conditions. The YCF1-expressing transgenic poplar plants exhibited enhanced growth, reduced toxicity symptoms, and increased Cd content in the aerial tissue compared to the non-transgenic plants. Furthermore, the plants accumulated increased amounts of Cd, Zn, and Pb in the root, because they could establish an extensive root system in mine tailing soil. These results suggest that the generation of YCF1-expressing transgenic poplar represents the first step towards producing plants for phytoremediation. The YCF1-expressing poplar may be useful for phytostabilization and phytoattenuation, especially in highly contaminated regions, where wild-type plants cannot survive.

  2. The Poplar GT8E and GT8F Glycosyltransferases are Functional Orthologs of Arabidopsis PARVUS Involved in Gulcuronoxylan Biosynthesis

    EPA Science Inventory

    The poplar GT8E and GT8F glycosyltransferases have previously been shown to be associated with wood formation, but their roles in the biosynthesis of wood components are not known. Here, we show that PoGT8E and PoGT8F are expressed in vessels and fibers during wood formation and ...

  3. Impact of an 8-Year-Old Transgenic Poplar Plantation on the Ectomycorrhizal Fungal Community ▿ †

    PubMed Central

    Stefani, Franck O. P.; Moncalvo, Jean-Marc; Séguin, Armand; Bérubé, Jean A.; Hamelin, Richard C.

    2009-01-01

    The long-term impact of field-deployed genetically modified trees on soil mutualistic organisms is not well known. This study aimed at evaluating the impact of poplars transformed with a binary vector containing the selectable nptII marker and β-glucuronidase reporter genes on ectomycorrhizal (EM) fungi 8 years after field deployment. We generated 2,229 fungal internal transcribed spacer (ITS) PCR products from 1,150 EM root tips and 1,079 fungal soil clones obtained from the organic and mineral soil horizons within the rhizosphere of three control and three transformed poplars. Fifty EM fungal operational taxonomic units were identified from the 1,706 EM fungal ITS amplicons retrieved. Rarefaction curves from both the root tips and soil clones were close to saturation, indicating that most of the EM species present were recovered. Based on qualitative and/or quantitative α- and β-diversity measurements, statistical analyses did not reveal significant differences between EM fungal communities associated with transformed poplars and the untransformed controls. However, EM communities recovered from the root tips and soil cloning analyses differed significantly from each other. We found no evidence of difference in the EM fungal community structure linked to the long-term presence of the transgenic poplars studied, and we showed that coupling root tip analysis with a soil DNA cloning strategy is a complementary approach to better document EM fungal diversity. PMID:19801471

  4. Reconnaissance evaluation of contamination in the alluvial aquifer in the East Poplar oil field, Roosevelt County, Montana

    USGS Publications Warehouse

    Levings, G.W.

    1984-01-01

    Water moving from north to south in the alluvial aquifer of the Poplar River valley becomes contaminated with sodium chloride in the area underlain by the East Poplar oil fields. Four types of ground water were identified in the study area. Type 1 is sodium bicarbonate water. Type 2 is sodium chloride water with varying quantities of calcium and magnesium. Type 3 water contains sodium and chloride in significantly larger concentrations than Type 2. Type 4 water is the brine being injected into brine-disposal wells. Contamination of the alluvial aquifer is indicated by a brine-freshwater interface in the alluvium, by downstream increase in chloride concentration of the Poplar River, and by downstream change in water type of the Poplar River. Contamination also may be indicated by the distribution of iron and manganese concentrations in water from wells near a brine-disposal well. Possible sources of sodium chloride contamination in the alluvium are brine-disposal wells, pipelines, and storage or evaporation pits. The contamination can occur from leaks in the casing of disposal wells or in pipelines caused by the corrosive nature of the brine or from storage or evaporation pits that have been improperly sealed or have sustained tears in the sealing material. (USGS)

  5. Proteins.

    ERIC Educational Resources Information Center

    Doolittle, Russell F.

    1985-01-01

    Examines proteins which give rise to structure and, by virtue of selective binding to other molecules, make genes. Binding sites, amino acids, protein evolution, and molecular paleontology are discussed. Work with encoding segments of deoxyribonucleic acid (exons) and noncoding stretches (introns) provides new information for hypotheses. (DH)

  6. Mammalian cytochrome CYP2E1 triggered differential gene regulation in response to trichloroethylene (TCE) in a transgenic poplar

    PubMed Central

    Kang, Jun Won; Wilkerson, Hui-Wen; Farin, Federico M.; Bammler, Theo K.; Beyer, Richard P.; Strand, Stuart E.

    2011-01-01

    Trichloroethylene (TCE) is an important environmental contaminant of soil, groundwater, and air. Studies of the metabolism of TCE by poplar trees suggest that cytochrome P450 enzymes are involved. Using poplar genome microarrays, we report a number of putative genes that are differentially expressed in response to TCE. In a previous study, transgenic hybrid poplar plants expressing mammalian cytochrome P450 2E1 (CYP2E1) had increased metabolism of TCE. In the vector control plants for this construct, 24 h following TCE exposure, 517 genes were upregulated and 650 genes were downregulated over 2-fold when compared with the non-exposed vector control plants. However, in the transgenic CYP2E1 plant, line 78, 1,601 genes were upregulated and 1,705 genes were downregulated over 2-fold when compared with the non-exposed transgenic CYP2E1 plant. It appeared that the CYP2E1 transgenic hybrid poplar plants overexpressing mammalian CYP2E1 showed a larger number of differentially expressed transcripts, suggesting a metabolic pathway for TCE to metabolites had been initiated by activity of CYP2E1 on TCE. These results suggest that either the over-expression of the CYP2E1 gene or the abundance of TCE metabolites from CYP450 2E1 activity triggered a strong genetic response to TCE. Particularly, cytochrome p450s, glutathione S-transferases, glucosyltransferases, and ABC transporters in the CYP2E1 transgenic hybrid poplar plants were highly expressed compared with in vector controls. PMID:20213342

  7. Gain-of-function analysis of poplar CLE genes in Arabidopsis by exogenous application and over-expression assays.

    PubMed

    Liu, Yisen; Yang, Shaohui; Song, Yingjin; Men, Shuzhen; Wang, Jiehua

    2016-04-01

    Among 50 CLE gene family members in the Populus trichocarpa genome, three and six PtCLE genes encode a CLE motif sequence highly homologous to Arabidopsis CLV3 and TDIF peptides, respectively, which potentially make them functional equivalents. To test and compare their biological activity, we first chemically synthesized each dodecapeptide and analysed itsi n vitro bioactivity on Arabidopsis seedlings. Similarly, but to a different extent, three types of poplar CLV3-related peptides caused root meristem consumption, phyllotaxis disorder, anthocyanin accumulation and failure to enter the bolting stage. In comparison, application of two poplar TDIF-related peptides led to root length promotion in a dose-dependent manner with an even stronger effect observed for poplar TDIF-like peptide than TDIF. Next, we constructed CaMV35S:PtCLE transgenic plants for each of the nine PtCLE genes. Phenotypic abnormalities exemplified by arrested shoot apical meristem and abnormal flower structure were found to be more dominant and severe in 35S:PtCLV3 and 35S:PtCLV3-like2 lines than in the 35S:PtCLV3-like line. Disordered vasculature was detected in both stem and hypocotyl cross-sections in Arabidopsis plants over-expressing poplar TDIF-related genes with the most defective vascular patterning observed for TDIF2 and two TDIF-like genes. Phenotypic difference consistently observed in peptide application assay and transgenic analysis indicated the functional diversity of nine poplar PtCLE genes under investigation. This work represents the first report on the functional analysis of CLE genes in a tree species and constitutes a basis for further study of the CLE peptide signalling pathway in tree development.

  8. Greater efficiency of water use in poplar clones having a delayed response of mesophyll conductance to drought.

    PubMed

    Théroux Rancourt, Guillaume; Éthier, Gilbert; Pepin, Steeve

    2015-02-01

    Improvement of water use efficiency is a key objective to improve the sustainability of cultivated plants, especially fast growing species with high water consumption like poplar. It is well known that water use efficiency (WUE) varies considerably among poplar genotypes, and it was recently suggested that the use of the mesophyll-to-stomatal conductance ratio (gm/gs) would be an appropriate trait to improve WUE. The responses of 7-week-old cuttings of four hybrid poplar clones and one native Balsam poplar (Populus balsamifera L.) to a water stress-recovery cycle were examined to evaluate the relation between the gm/gs ratio and transpiration efficiency (TE), a leaf-level component of WUE. A contrasting gs response to water stress was observed among the five clones, from stomatal closure early on during soil drying up to limited closure in Balsam poplar. However in the hybrids, the decline in gm was consistently delayed by a few days compared with gs. Moreover, in the most water use-efficient hybrids, the recovery following rehydration occurred faster for gm than for gs. Thus, the delay in the response of gm to drought and its faster recovery upon rewatering increased the gm/gs of the hybrids and this ratio scaled positively with TE. Our results support the use of the gm/gs ratio to select genotypes with improved WUE, and the notion that breeding strategies focusing mainly on stomatal responses to soil drying should also look for a strong curvilinearity between net carbon assimilation rate and gs, the indication of a significant increase in gm/gs in the earlier stages of stomatal closure.

  9. Protein

    MedlinePlus

    ... Search for: Harvard T.H. Chan School of Public Health Email People Departments Calendar Careers Give my.harvard ... Nutrition Source Harvard T.H. Chan School of Public Health > The Nutrition Source > What Should I Eat? > Protein ...

  10. Protein

    MedlinePlus

    ... Go lean with protein. • Choose lean meats and poultry. Lean beef cuts include round steaks (top loin, ... main dishes. • Use nuts to replace meat or poultry, not in addition to meat or poultry (i. ...

  11. Final report from VFL Technologies for the pilot-scale thermal treatment of lower East Fork Poplar Creek floodplain soils. LEFPC appendices, Volume 4, Appendix V-C

    SciTech Connect

    1994-09-01

    This is the the final verification run data package for pilot scale thermal treatment of lower East Fork Poplar Creek floodplain soils. Included are data on volatiles, semivolatiles, and TCLP volatiles.

  12. Final report from VFL technologies for the pilot-scale thermal treatment of Lower East Fork Poplar Creek floodplain soils: LEFPC appendices, volume 1, appendix I-IV

    SciTech Connect

    1994-09-01

    This document contains Appendix I-IV for the pilot-scale thermal treatment of lower East Fork Poplar Creek floodplain soils. Included are calibration records; quality assurance; soils characterization; pilot scale trial runs.

  13. Matching the Best Viewing Angle in Depth Cameras for Biomass Estimation Based on Poplar Seedling Geometry

    PubMed Central

    Andújar, Dionisio; Fernández-Quintanilla, César; Dorado, José

    2015-01-01

    In energy crops for biomass production a proper plant structure is important to optimize wood yields. A precise crop characterization in early stages may contribute to the choice of proper cropping techniques. This study assesses the potential of the Microsoft Kinect for Windows v.1 sensor to determine the best viewing angle of the sensor to estimate the plant biomass based on poplar seedling geometry. Kinect Fusion algorithms were used to generate a 3D point cloud from the depth video stream. The sensor was mounted in different positions facing the tree in order to obtain depth (RGB-D) images from different angles. Individuals of two different ages, e.g., one month and one year old, were scanned. Four different viewing angles were compared: top view (0°), 45° downwards view, front view (90°) and ground upwards view (−45°). The ground-truth used to validate the sensor readings consisted of a destructive sampling in which the height, leaf area and biomass (dry weight basis) were measured in each individual plant. The depth image models agreed well with 45°, 90° and −45° measurements in one-year poplar trees. Good correlations (0.88 to 0.92) between dry biomass and the area measured with the Kinect were found. In addition, plant height was accurately estimated with a few centimeters error. The comparison between different viewing angles revealed that top views showed poorer results due to the fact the top leaves occluded the rest of the tree. However, the other views led to good results. Conversely, small poplars showed better correlations with actual parameters from the top view (0°). Therefore, although the Microsoft Kinect for Windows v.1 sensor provides good opportunities for biomass estimation, the viewing angle must be chosen taking into account the developmental stage of the crop and the desired parameters. The results of this study indicate that Kinect is a promising tool for a rapid canopy characterization, i.e., for estimating crop biomass

  14. Matching the best viewing angle in depth cameras for biomass estimation based on poplar seedling geometry.

    PubMed

    Andújar, Dionisio; Fernández-Quintanilla, César; Dorado, José

    2015-06-04

    In energy crops for biomass production a proper plant structure is important to optimize wood yields. A precise crop characterization in early stages may contribute to the choice of proper cropping techniques. This study assesses the potential of the Microsoft Kinect for Windows v.1 sensor to determine the best viewing angle of the sensor to estimate the plant biomass based on poplar seedling geometry. Kinect Fusion algorithms were used to generate a 3D point cloud from the depth video stream. The sensor was mounted in different positions facing the tree in order to obtain depth (RGB-D) images from different angles. Individuals of two different ages, e.g., one month and one year old, were scanned. Four different viewing angles were compared: top view (0°), 45° downwards view, front view (90°) and ground upwards view (-45°). The ground-truth used to validate the sensor readings consisted of a destructive sampling in which the height, leaf area and biomass (dry weight basis) were measured in each individual plant. The depth image models agreed well with 45°, 90° and -45° measurements in one-year poplar trees. Good correlations (0.88 to 0.92) between dry biomass and the area measured with the Kinect were found. In addition, plant height was accurately estimated with a few centimeters error. The comparison between different viewing angles revealed that top views showed poorer results due to the fact the top leaves occluded the rest of the tree. However, the other views led to good results. Conversely, small poplars showed better correlations with actual parameters from the top view (0°). Therefore, although the Microsoft Kinect for Windows v.1 sensor provides good opportunities for biomass estimation, the viewing angle must be chosen taking into account the developmental stage of the crop and the desired parameters. The results of this study indicate that Kinect is a promising tool for a rapid canopy characterization, i.e., for estimating crop biomass

  15. Use of active extracts of poplar buds against Penicillium italicum and possible modes of action.

    PubMed

    Yang, Shuzhen; Liu, Limei; Li, Dongmei; Xia, Huan; Su, Xiaojun; Peng, Litao; Pan, Siyi

    2016-04-01

    Antifungal components, from poplar buds active fraction (PBAF) against Penicillium italicum, the causal agent of blue mold in citrus fruits, were identified and possible action modes were investigated. Pinocembrin, chrysin and galangin were determined as active components in PBAF, using HPLC and HPLC-MS analysis. The antifungal activity is stable at temperatures ranging from 4 °C to 100 °C and pH levels ranging from 4 to 8. In the presence of PBAF, the hyphae become shriveled, wrinkled and the cell membrane became seriously disrupted. Further investigation on cell permeability, nucleic acid content and alkaline phosphatase suggest that the cell membrane might be the target. Mycelial oxygen consumption and the respiration-related enzymatic activity of succinate dehydrogenase, malate dehydrogenase and ATPase were all inhibited by PBAF. We propose that PBAF is a potentially useful alternative for blue mold control and may act against P. italicum by interfering with respiration and disrupting the cell membrane.

  16. A study of poplar organosolv lignin after melt rheology treatment as carbon fiber precursors

    DOE PAGES

    Sun, Qining; Khunsupat, Ratayakorn; Akato, Kokouvi; ...

    2016-06-16

    Lignins from various poplar genotypes were isolated by using organosolv fractionation and subjected to rheological treatment at various temperatures. Physicochemical characterization of the lignin variants shows a broad distribution of glass transition temperatures, melt viscosity, and pyrolysis char residues. Rheological treatment at 170 °C induces lignin repolymerization accompanied with an increase in condensed linkages, molecular weights, and viscosities. In contrast, rheology testing at 190 °C results in the decrease in lignin aliphatic and phenolic hydroxyl groups, β-O-aryl ether linkages, molecular weights, and viscosity values. Lignin under air cooling generates more oxygenated and condensed compounds, but lower amounts of ether linkagesmore » than lignin cooled under nitrogen. Here, lignin with a lower syringyl/guaiacyl ratio tends to form more cross-linkages along with higher viscosity values, higher molecular weight and larger amounts of condensed bonds.« less

  17. A study of poplar organosolv lignin after melt rheology treatment as carbon fiber precursors

    SciTech Connect

    Sun, Qining; Khunsupat, Ratayakorn; Akato, Kokouvi; Tao, Jingming; Labbe, Nicole; Gallego, Nidia C.; Bozell, Joseph J.; Rials, Timothy G.; Tuskan, Gerald A.; Tschaplinski, Timothy J.; Naskar, Amit K.; Pu, Yunqiao; Ragauskas, Arthur J.

    2016-06-16

    Lignins from various poplar genotypes were isolated by using organosolv fractionation and subjected to rheological treatment at various temperatures. Physicochemical characterization of the lignin variants shows a broad distribution of glass transition temperatures, melt viscosity, and pyrolysis char residues. Rheological treatment at 170 °C induces lignin repolymerization accompanied with an increase in condensed linkages, molecular weights, and viscosities. In contrast, rheology testing at 190 °C results in the decrease in lignin aliphatic and phenolic hydroxyl groups, β-O-aryl ether linkages, molecular weights, and viscosity values. Lignin under air cooling generates more oxygenated and condensed compounds, but lower amounts of ether linkages than lignin cooled under nitrogen. Here, lignin with a lower syringyl/guaiacyl ratio tends to form more cross-linkages along with higher viscosity values, higher molecular weight and larger amounts of condensed bonds.

  18. Mercury Remediation Technology Development for Lower East Fork Poplar Creek - FY 2015 Progress Report

    SciTech Connect

    Peterson, Mark J.; Brooks, Scott C.; Mathews, Teresa J.; Mayes, Melanie; Johs, Alexander; Watson, David B.; Poteat, Monica D.; Smith, John; Mehlhorn, Tonia; Lester, Brian; Morris, Jesse; Lowe, Kenneth; Dickson, Johnbull O.; Eller, Virginia; DeRolph, Christopher R.

    2016-04-01

    Mercury remediation is a high priority for the US Department of Energy (DOE) Oak Ridge Office of Environmental Management (OREM) because of large historical losses of mercury within buildings and to soils and surface waters at the Y-12 National Security Complex (Y-12). Because of the extent of mercury losses and the complexities of mercury transport and fate in the downstream environment, the success of conventional options for mercury remediation in lower East Fork Poplar Creek (EFPC) is uncertain. A phased, adaptive management approach to remediation of surface water includes mercury treatment actions at Y-12 in the short-term and research and technology development (TD) to evaluate longer-term solutions in the downstream environment (US Department of Energy 2014b).

  19. Beetle feeding induces a different volatile emission pattern from black poplar foliage than caterpillar herbivory

    PubMed Central

    Unsicker, Sybille B.; Gershenzon, Jonathan; Köllner, Tobias G.

    2015-01-01

    Herbivore-induced plant volatile emission is often considered to be attacker species-specific, but most experimental evidence comes from short lived herbaceous species. In a recent study we showed that black poplar (Populus nigra) trees emit a complex blend of volatiles from damaged leaves when they are attacked by generalist gypsy moth (Lymantria dispar) caterpillars. Minor nitrogenous volatiles were especially characteristic of this blend. Here we show that attack on P. nigra by a beetle species, Phratora vulgatissima (Coleoptera, Chrysomelidae), led to the emission of the same compounds as already observed after caterpillar herbivory, but with striking quantitative changes in the blend. The consequences for attraction of herbivore enemies are discussed. PMID:25831045

  20. Assimilate movement dictates remote sites of wound-induced gene expression in poplar leaves.

    PubMed

    Davis, J M; Gordon, M P; Smit, B A

    1991-03-15

    When a single leaf on a young poplar tree is mechanically wounded, wound-induced (win) mRNAs are detected in the unwounded portion of that leaf and in specific leaves that are remote from the wounded leaf. Shortly after wounding (6-8 hr), the remote leaves in which win genes are expressed can be predicted by a knowledge of photoassimilate movement patterns in vivo. When assimilate movement from a wounded leaf is blocked or the direction of assimilate movement is altered by shading, win gene expression in remote leaves is similarly blocked or altered. These data illustrate how the long-distance transduction of wound-induced signals can be manipulated in plants by altering carbon allocation.

  1. Application of Fenton's reaction to steam explosion prehydrolysates from poplar biomass.

    PubMed

    Oliva, J M; Manzanares, P; Ballesteros, I; Negro, M J; González, A; Ballesteros, M

    2005-01-01

    The application of Fenton's reaction to enhance the fermentability of prehydrolysates obtained from steam explosion pretreatment of poplar biomass was studied. Reaction conditions of temperature and H2O2 and Fe(II) concentrations were studied. The fermentability of prehydrolysate treated by Fenton's reaction was tested by using different inoculum sizes of thermotolerant strain Kluyveromyces marxianus CECT 10875. The highest percentages of toxic compound degradation (ranging from 71 to 93% removal) were obtained at the highest H2O2 concentration tested (50 mM). However, a negative effect on fermentability was observed at this H2O2 concentration at the lower inoculum loading. An increase in inoculum size to 0.6 g/L resulted in an enhanced ethanol fermentation yield of 95% relative to control.

  2. Steam gasification of tyre waste, poplar, and refuse-derived fuel: A comparative analysis

    SciTech Connect

    Galvagno, S. Casciaro, G.; Casu, S.; Martino, M.; Mingazzini, C.; Russo, A.; Portofino, S.

    2009-02-15

    In the field of waste management, thermal disposal is a treatment option able to recover resources from 'end of life' products. Pyrolysis and gasification are emerging thermal treatments that work under less drastic conditions in comparison with classic direct combustion, providing for reduced gaseous emissions of heavy metals. Moreover, they allow better recovery efficiency since the process by-products can be used as fuels (gas, oils), for both conventional (classic engines and heaters) and high efficiency apparatus (gas turbines and fuel cells), or alternatively as chemical sources or as raw materials for other processes. This paper presents a comparative study of a steam gasification process applied to three different waste types (refuse-derived fuel, poplar wood and scrap tyres), with the aim of comparing the corresponding yields and product compositions and exploring the most valuable uses of the by-products.

  3. Robustness of two-step acid hydrolysis procedure for composition analysis of poplar.

    PubMed

    Bhagia, Samarthya; Nunez, Angelica; Wyman, Charles E; Kumar, Rajeev

    2016-09-01

    The NREL standard procedure for lignocellulosic biomass composition has two steps: primary hydrolysis in 72% wt sulfuric acid at 30°C for 1h followed by secondary hydrolysis of the slurry in 4wt% acid at 121°C for 1h. Although pointed out in the NREL procedure, the impact of particle size on composition has never been shown. In addition, the effects of primary hydrolysis time and separation of solids prior to secondary hydrolysis on composition have never been shown. Using poplar, it was found that particle sizes less than 0.250mm significantly lowered the glucan content and increased the Klason lignin but did not affect xylan, acetate, or acid soluble lignin contents. Composition was unaffected for primary hydrolysis time between 30 and 90min. Moreover, separating solids prior to secondary hydrolysis had negligible effect on composition suggesting that lignin and polysaccharides are completely separated in the primary hydrolysis stage.

  4. The mechano-sorptive behavior of poplar during high-temperature drying

    SciTech Connect

    Dagang, L.; Lianbai, G.

    1999-10-01

    In this study the mechano-sorptive creep perpendicular to the grain was demonstrated by an experimental technique based on the analysis of strain of 30mm thick fast-growing poplar lumber. For levels of drying temperatures (85 C, 105 C, 115 C and 125 C) were used to dry the wood. The overall board shrinkage and the immediately released and set strains were measured as a function of time. The total strain that occurs in lumber drying is the sum of four components: elastic strain, shrinkage strain, visco-elastic creep strain and mechano-sorptive creep strain. The elastic and visco-elastic components of creep are small and produced immediately after the creation of stress. Mechano-sorptive creep is the major strain that causes casehardening during drying.

  5. Insect regurgitant and wounding elicit similar defense responses in poplar leaves: not something to spit at?

    PubMed

    Major, Ian T; Constabel, C Peter

    2007-01-01

    How plants perceive insect attacks is an area of active research. Numerous studies have shown that regurgitant from feeding insects elicits a defense response in plants, which is often assumed to be distinct from a wound response. We have characterized the inducible defense response in hybrid poplar and found it to be qualitatively similar between wounding and application of regurgitant from forest tent caterpillar. We suggest that this is likely attributable to our wounding treatment which is much more intense compared to most other studies. These overlapping responses appear to be activated via jasmonic acid signaling, and we speculate that they are both triggered by elicitors of plant origin. Wounding would release such elicitor molecules when leaf cells are disrupted, and regurgitant may contain them in a modified or processed form. This hypothesis could explain why some other necrosis-inducing stresses also induce herbivore defense genes.

  6. Steam gasification of tyre waste, poplar, and refuse-derived fuel: a comparative analysis.

    PubMed

    Galvagno, S; Casciaro, G; Casu, S; Martino, M; Mingazzini, C; Russo, A; Portofino, S

    2009-02-01

    In the field of waste management, thermal disposal is a treatment option able to recover resources from "end of life" products. Pyrolysis and gasification are emerging thermal treatments that work under less drastic conditions in comparison with classic direct combustion, providing for reduced gaseous emissions of heavy metals. Moreover, they allow better recovery efficiency since the process by-products can be used as fuels (gas, oils), for both conventional (classic engines and heaters) and high efficiency apparatus (gas turbines and fuel cells), or alternatively as chemical sources or as raw materials for other processes. This paper presents a comparative study of a steam gasification process applied to three different waste types (refuse-derived fuel, poplar wood and scrap tyres), with the aim of comparing the corresponding yields and product compositions and exploring the most valuable uses of the by-products.

  7. Decreased transpiration in poplar trees exposed to 2,4,6-trinitrotoluene

    SciTech Connect

    Thompson, P.L.; Ramer, L.A.; Guffey, A.P.; Schnoor, J.L.

    1998-01-01

    The improper handling of the toxic compound 2,4,6-trinitrotoluene (TNT) has led to the contamination of soil and groundwater, and the uptake of TNT by a variety of plants has been established. This article discusses the effects of various concentrations of the explosive 2,4,6-trinitrotoluene (TNT) on the transpiration of hybrid poplar trees growing in hydroponic media. Transpiration was measured daily by gravimetric means. The rapid removal of TNT from hydroponic solutions was a result of plant uptake and required a daily dosage of TNT to ensure a relatively constant exposure over time. Transpiration decreased with increasing TNT concentrations {ge}5 mg/L. Decreases in transpiration were accompanied by leaf chlorosis and abscission. A comparison between a laboratory study and a pilot-scale experiment showed good scale-up potential.

  8. Evaluating ascorbate oxidase as a plant defense against leaf-chewing insects using transgenic poplar.

    PubMed

    Barbehenn, Raymond V; Jaros, Adam; Yip, Lynn; Tran, Lan; Kanellis, Angelos K; Constabel, C Peter

    2008-10-01

    Ascorbate is the major water-soluble antioxidant in plants and animals, and it is an essential nutrient for most insect herbivores. Therefore, ascorbate oxidase (AO) has been proposed to function as a plant defense that decreases the availability of ascorbate to insects. This hypothesis was tested by producing transgenic poplar (Populus tremula x Populus alba; Salicaceae) with 14- to 37-fold higher foliar AO activities than control (wild type) leaves and feeding these leaves to Lymantria dispar L. (Lepidoptera: Lymantriidae) caterpillars and Melanoplus sanguinipes (Fabricius) (Orthoptera: Acrididae) grasshoppers. To examine potential mechanisms of activity of AO in these insects, ascorbyl radical and/or ascorbate levels were measured in gut contents. No significant changes in ascorbyl radical or ascorbate levels were found in the midgut contents of L. dispar larvae that ingested the leaves of the AO-overexpressing genotypes compared to the control genotype, and no significant decreases in ascorbate levels were found in the foregut or midgut contents of M. sanguinipes. Treatment of control leaves with commercial AO also produced no changes in the midgut biochemistry of L. dispar larvae, as measured by levels of ascorbyl radicals. Likewise, no increase in oxidative stress was observed in L. dispar that consumed tannin-treated AO-overexpressing leaves compared with tannin-treated control genotype leaves. Performance experiments were carried out on first- and fourth-instar L. dispar larvae on leaf disks and on third instars feeding on intact leaves on trees. In no case was a significant difference found in the contrast between the control and three AO-overexpressing genotypes for relative consumption rate, relative growth rate, or nutritional indices. We conclude that elevated levels of AO in poplar are unlikely to serve as a defense against herbivores such as L. dispar or M. sanguinipes and that the low oxygen levels commonly found in the guts of caterpillars and

  9. Water use of a multigenotype poplar short-rotation coppice from tree to stand scale.

    PubMed

    Bloemen, Jasper; Fichot, Régis; Horemans, Joanna A; Broeckx, Laura S; Verlinden, Melanie S; Zenone, Terenzio; Ceulemans, Reinhart

    2017-02-01

    Short-rotation coppice (SRC) has great potential for supplying biomass-based heat and energy, but little is known about SRC's ecological footprint, particularly its impact on the water cycle. To this end, we quantified the water use of a commercial scale poplar (Populus) SRC plantation in East Flanders (Belgium) at tree and stand level, focusing primarily on the transpiration component. First, we used the AquaCrop model and eddy covariance flux data to analyse the different components of the stand-level water balance for one entire growing season. Transpiration represented 59% of evapotranspiration (ET) at stand scale over the whole year. Measured ET and modelled ET were lower as compared to the ET of reference grassland, suggesting that the SRC only used a limited amount of water. Secondly, we compared leaf area scaled and sapwood area scaled sap flow (Fs) measurements on individual plants vs. stand scale eddy covariance flux data during a 39-day intensive field campaign in late summer 2011. Daily stem diameter variation (∆D) was monitored simultaneously with Fs to understand water use strategies for three poplar genotypes. Canopy transpiration based on sapwood area or leaf area scaling was 43.5 and 50.3 mm, respectively, and accounted for 74%, respectively, 86%, of total ecosystem ET measured during the intensive field campaign. Besides differences in growth, the significant intergenotypic differences in daily ∆D (due to stem shrinkage and swelling) suggested different water use strategies among the three genotypes which were confirmed by the sap flow measurements. Future studies on the prediction of SRC water use, or efforts to enhance the biomass yield of SRC genotypes, should consider intergenotypic differences in transpiration water losses at tree level as well as the SRC water balance at stand level.

  10. Contribution of different carbon sources to isoprene biosynthesis in poplar leaves.

    PubMed

    Schnitzler, Jörg-Peter; Graus, Martin; Kreuzwieser, Jürgen; Heizmann, Ulrike; Rennenberg, Heinz; Wisthaler, Armin; Hansel, Armin

    2004-05-01

    This study was performed to test if alternative carbon sources besides recently photosynthetically fixed CO2 are used for isoprene formation in the leaves of young poplar (Populus x canescens) trees. In a 13CO2 atmosphere under steady state conditions, only about 75% of isoprene became 13C labeled within minutes. A considerable part of the unlabeled carbon may be derived from xylem transported carbohydrates, as may be shown by feeding leaves with [U-13C]Glc. As a consequence of this treatment approximately 8% to 10% of the carbon emitted as isoprene was 13C labeled. In order to identify further carbon sources, poplar leaves were depleted of leaf internal carbon pools and the carbon pools were refilled with 13C labeled carbon by exposure to 13CO2. Results from this treatment showed that about 30% of isoprene carbon became 13C labeled, clearly suggesting that, in addition to xylem transported carbon and CO2, leaf internal carbon pools, e.g. starch, are used for isoprene formation. This use was even increased when net assimilation was reduced, for example by abscisic acid application. The data provide clear evidence of a dynamic exchange of carbon between different cellular precursors for isoprene biosynthesis, and an increasing importance of these alternative carbon pools under conditions of limited photosynthesis. Feeding [1,2-13C]Glc and [3-13C]Glc to leaves via the xylem suggested that alternative carbon sources are probably derived from cytosolic pyruvate/phosphoenolpyruvate equivalents and incorporated into isoprene according to the predicted cleavage of the 3-C position of pyruvate during the initial step of the plastidic deoxyxylulose-5-phosphate pathway.

  11. Moderate salt treatment alleviates ultraviolet-B radiation caused impairment in poplar plants

    PubMed Central

    Ma, Xuan; Ou, Yong-Bin; Gao, Yong-Feng; Lutts, Stanley; Li, Tao-Tao; Wang, Yang; Chen, Yong-Fu; Sun, Yu-Fang; Yao, Yin-An

    2016-01-01

    The effects of moderate salinity on the responses of woody plants to UV-B radiation were investigated using two Populus species (Populus alba and Populus russkii). Under UV-B radiation, moderate salinity reduced the oxidation pressure in both species, as indicated by lower levels of cellular H2O2 and membrane peroxidation, and weakened the inhibition of photochemical efficiency expressed by O-J-I-P changes. UV-B-induced DNA lesions in chloroplast and nucleus were alleviated by salinity, which could be explained by the higher expression levels of DNA repair system genes under UV-B&salt condition, such as the PHR, DDB2, and MutSα genes. The salt-induced increase in organic osmolytes proline and glycine betaine, afforded more efficient protection against UV-B radiation. Therefore moderate salinity induced cross-tolerance to UV-B stress in poplar plants. It is thus suggested that woody plants growing in moderate salted condition would be less affected by enhanced UV-B radiation than plants growing in the absence of salt. Our results also showed that UV-B signal genes in poplar plants PaCOP1, PaSTO and PaSTH2 were quickly responding to UV-B radiation, but not to salt. The transcripts of PaHY5 and its downstream pathway genes (PaCHS1, PaCHS4, PaFLS1 and PaFLS2) were differently up-regulated by these treatments, but the flavonoid compounds were not involved in the cross-tolerance since their concentration increased to the same extent in both UV-B and combined stresses. PMID:27597726

  12. Effects of soil contamination by trace elements on white poplar progeny: seed germination and seedling vigour.

    PubMed

    Madejón, Paula; Cantos, Manuel; Jiménez-Ramos, María C; Marañón, Teodoro; Murillo, José M

    2015-11-01

    Seed germination is considered a critical phase in plant development and relatively sensitive to heavy metals. White poplar (Populus alba) trees tend to accumulate Cd and Zn in their tissues. We tested if soil contamination can affect P. alba progeny, reduced seed germination and explored the distribution of mineral elements in the seed. For this purpose, fruits and seeds from female P. alba trees were selected from two contaminated and one non-contaminated areas. Seeds from all the sites were germinated using only water or a nutritive solution (in vitro). Concentrations of nutrients and trace elements in the fruits and seeds were analysed. Seedling growth in vitro was also analysed. Finally, a mapping of different elements within the poplar seed was obtained by particle-induced X-ray emission (PIXE). Germination was similar between different progenies, refuting our hypothesis that seeds from a contaminated origin would have reduced germination capacity compared to those from a non-contaminated site. Seedling growth was not affected by the contaminated origin. Cadmium and Zn concentrations in fruits produced by P. alba trees in the contaminated sites were higher than by those from the non-contaminated site. However, the nutritional status of the trees was adequate in both cases. Cd in seedlings was higher in those from contaminated soils although lower than in fruits, indicating a certain exclusion from seeds. Preliminary results of the PIXE technique showed that Al and Zn were distributed uniformly in the seeds (Cd was not detected with this technique), while the nutrients P and S were concentrated in the cotyledons.

  13. Moderate salt treatment alleviates ultraviolet-B radiation caused impairment in poplar plants

    NASA Astrophysics Data System (ADS)

    Ma, Xuan; Ou, Yong-Bin; Gao, Yong-Feng; Lutts, Stanley; Li, Tao-Tao; Wang, Yang; Chen, Yong-Fu; Sun, Yu-Fang; Yao, Yin-An

    2016-09-01

    The effects of moderate salinity on the responses of woody plants to UV-B radiation were investigated using two Populus species (Populus alba and Populus russkii). Under UV-B radiation, moderate salinity reduced the oxidation pressure in both species, as indicated by lower levels of cellular H2O2 and membrane peroxidation, and weakened the inhibition of photochemical efficiency expressed by O-J-I-P changes. UV-B-induced DNA lesions in chloroplast and nucleus were alleviated by salinity, which could be explained by the higher expression levels of DNA repair system genes under UV-B&salt condition, such as the PHR, DDB2, and MutSα genes. The salt-induced increase in organic osmolytes proline and glycine betaine, afforded more efficient protection against UV-B radiation. Therefore moderate salinity induced cross-tolerance to UV-B stress in poplar plants. It is thus suggested that woody plants growing in moderate salted condition would be less affected by enhanced UV-B radiation than plants growing in the absence of salt. Our results also showed that UV-B signal genes in poplar plants PaCOP1, PaSTO and PaSTH2 were quickly responding to UV-B radiation, but not to salt. The transcripts of PaHY5 and its downstream pathway genes (PaCHS1, PaCHS4, PaFLS1 and PaFLS2) were differently up-regulated by these treatments, but the flavonoid compounds were not involved in the cross-tolerance since their concentration increased to the same extent in both UV-B and combined stresses.

  14. Comparative water use by maize, perennial crops, restored prairie, and poplar trees in the US Midwest

    NASA Astrophysics Data System (ADS)

    Hamilton, S. K.; Hussain, M. Z.; Bhardwaj, A. K.; Basso, B.; Robertson, G. P.

    2015-06-01

    Water use by plant communities across years of varying water availability indicates how terrestrial water balances will respond to climate change and variability as well as to land cover change. Perennial biofuel crops, likely grown mainly on marginal lands of limited water availability, provide an example of a potentially extensive future land cover conversion. We measured growing-season evapotranspiration (ET) based on daily changes in soil profile water contents in five perennial systems—switchgrass, miscanthus, native grasses, restored prairie, and hybrid poplar—and in annual maize (corn) in a temperate humid climate (Michigan, USA). Three study years (2010, 2011 and 2013) had normal growing-season rainfall (480-610 mm) whereas 2012 was a drought year (210 mm). Over all four years, mean (±SEM) growing-season ET for perennial systems did not greatly differ from corn (496 ± 21 mm), averaging 559 (±14), 458 (±31), 573 (±37), 519 (±30), and 492 (±58) mm for switchgrass, miscanthus, native grasses, prairie, and poplar, respectively. Differences in biomass production largely determined variation in water use efficiency (WUE). Miscanthus had the highest WUE in both normal and drought years (52-67 and 43 kg dry biomass ha-1 mm-1, respectively), followed by maize (40-59 and 29 kg ha-1 mm-1) the native grasses and prairie were lower and poplar was intermediate. That measured water use by perennial systems was similar to maize across normal and drought years contrasts with earlier modeling studies and suggests that rain-fed perennial biomass crops in this climate have little impact on landscape water balances, whether replacing rain-fed maize on arable lands or successional vegetation on marginal lands. Results also suggest that crop ET rates, and thus groundwater recharge, streamflow, and lake levels, may be less sensitive to climate change than has been assumed.

  15. Investigating the drought-stress response of hybrid poplar genotypes by metabolite profiling.

    PubMed

    Barchet, Genoa L H; Dauwe, Rebecca; Guy, Robert D; Schroeder, William R; Soolanayakanahally, Raju Y; Campbell, Malcolm M; Mansfield, Shawn D

    2014-11-01

    Drought stress is perhaps the most commonly encountered abiotic stress plants experience in the natural environment, and it is one of the most important factors limiting plant productivity. Here, we employed untargeted metabolite profiling to examine four drought-stressed hybrid poplar (Populus spp.) genotypes for their metabolite content, using gas chromatography coupled to mass spectrometry. The primary objective of these analyses was to characterize the metabolite profile of poplar trees to assess relative drought resistance and to investigate the underlying biochemical mechanisms employed by the genotypes to combat drought. Metabolite profiling identified key metabolites that increased or decreased in relative abundance upon exposure to drought stress. Overall, amino acids, the antioxidant phenolic compounds catechin and kaempferol, as well as the osmolytes raffinose and galactinol exhibited increased abundance under drought stress, whereas metabolites involved in photorespiration, redox regulation and carbon fixation showed decreased abundance under drought stress. One clone in particular, Okanese, displayed unique responses to the imposed drought conditions. This clone was found to have higher leaf water potential, but lower growth rate relative to the other clones tested. Okanese also had lower accumulation of osmolytes such as raffinose, galactinol and proline, but higher overall levels of antioxidants such as catechin and dehydroascorbic acid. As such, it was proposed that osmotic adjustment as a mechanism for drought avoidance in this clone is not as well developed in comparison with the other clones investigated in this study, and that a possible alternative mechanism for the enhanced drought avoidance displayed by Okanese may be due to differential allocation of resources or better retention of water.

  16. Ecological risk assessment of aerial insectivores of the Clinch River/Poplar Creek system

    SciTech Connect

    Baron, L.A.; Sample, B.E.

    1995-12-31

    Risks to aerial insectivores (species that consume flying insects; rough-winged swallows, little brown bats, and endangered gray bats) were assessed for the CERCLA remedial investigation of the Clinch River/Poplar Creek system. Adult mayflies and sediment were collected from four locations and analyzed for contaminants. Sediment-to-mayfly contaminant transfer factors were generated from these data and used to estimate contaminant concentrations in mayflies from thirteen additional locations. Contaminants of potential concern (COPCs) were identified by comparing exposure estimates, generated using point estimates of parameter values, to NOAELS. COPCs included mercury, arsenic, and PCBs. Exposure to COPCs was re-estimated using Monte Carlo simulations. Adverse population effects were assumed likely if > 20% of the estimated exposure distribution was greater than the LOAEL. Exposure of swallows to mercury was a significant risk at two locations. Exposure of bats to mercury was a significant risk at only one location. While consideration of movement and foraging territory did not reduce estimated risks to swallows, when exposures for gray and little brown bats were re-estimated, population-level risks from mercury were no longer considered likely. As an endangered species however, protection is extended to individual gray bats. While less than 20% of the mercury exposure distribution for gray bats was > LOAEL, > 99% of the distribution was >NOAEL. Therefore, adverse effects may occur among maximally exposed individual gray bats. Available data indicate that contaminants in Poplar Creek are likely to present a risk to the swallow population, do not present a risk to the little brown bat population, and may present a risk to individual gray bats.

  17. Poplar demand.

    PubMed Central

    Holton, W C

    1998-01-01

    Trichloroethylene (TCE) is a common industrial solvent that poses a particular pollution problem in groundwater; while TCE disappears from surface water within a few weeks, groundwater contamination can take months or years to degrade. Humans have not conclusively been shown to develop cancer in response to TCE exposure, but rats and mice exposed to TCE have an increased incidence of liver and lung cancers. PMID:9721263

  18. The influence of lignin on steam pretreatment and mechanical pulping of poplar to achieve high sugar recovery and ease of enzymatic hydrolysis.

    PubMed

    Chandra, Richard P; Chu, QiuLu; Hu, Jinguang; Zhong, Na; Lin, Mandy; Lee, Jin-Suk; Saddler, Jack

    2016-01-01

    With the goal of enhancing overall carbohydrate recovery and reducing enzyme loading refiner mechanical pulping and steam pretreatment (210°C, 5 min) were used to pretreat poplar wood chips. Neutral sulphonation post-treatment indicated that, although the lignin present in the steam pretreated substrate was less reactive, the cellulose-rich, water insoluble component was more accessible to cellulases and Simons stain. This was likely due to lignin relocation as the relative surface lignin measured by X-ray photoelectron spectroscopy increased from 0.4 to 0.8. The integration of sulphite directly into steam pretreatment resulted in the solubilisation of 60% of the lignin while more than 80% of the carbohydrate present in the original substrate was recovered in the water insoluble fraction after Na2CO3 addition. More than 80% of the sugars present in the original cellulose and xylan could be recovered after 48 h using an enzyme loading of 20 mg protein/g cellulose at a 10% substrate concentration.

  19. An Improved Approach for Mapping Quantitative Trait loci in a Pseudo-Testcross: Revisiting a Poplar Mapping Study

    SciTech Connect

    Wullschleger, Stan D; Wu, Song; Wu, Rongling; Yang, Jie; Li, Yao; Yin, Tongming; Tuskan, Gerald A

    2010-01-01

    A pseudo-testcross pedigree is widely used for mapping quantitative trait loci (QTL) in outcrossing species, but the model for analyzing pseudo-testcross data borrowed from the inbred backcross design can only detect those QTLs that are heterozygous only in one parent. In this study, an intercross model that incorporates the high heterozygosity and phase uncertainty of outcrossing species was used to reanalyze a published data set on QTL mapping in poplar trees. Several intercross QTLs that are heterozygous in both parents were detected, which are responsible not only for biomass traits, but also for their genetic correlations. This study provides a more complete identification of QTLs responsible for economically important biomass traits in poplars.

  20. An Improved Approach for Mapping Quantitative Trait Loci in a Pseudo-Testcross: Revisiting a Poplar Mapping Study

    SciTech Connect

    Tuskan, Gerald A; Yin, Tongming; Wullschleger, Stan D; Yang, Jie; Huang, Youjun; Li, Yao; Wu, Rongling

    2010-01-01

    A pseudo-testcross pedigree is widely used for mapping quantitative trait loci (QTL) in outcrossing species, but the model for analyzing pseudo-testcross data borrowed from the inbred backcross design can only detect those QTLs that are heterozygous only in one parent. In this study, an intercross model that incorporates the high heterozygosity and phase uncertainty of outcrossing species was used to reanalyze a published data set on QTL mapping in poplar trees. Several intercross QTLs that are heterozygous in both parents were detected, which are responsible not only for biomass traits, but also for their genetic correlations. This study provides a more complete identification of QTLs responsible for economically important biomass traits in poplars.

  1. An improved approach for mapping quantitative trait Loci in a pseudo-testcross: revisiting a poplar mapping study.

    PubMed

    Wu, Song; Yang, Jie; Huang, Youjun; Li, Yao; Yin, Tongming; Wullschleger, Stan D; Tuskan, Gerald A; Wu, Rongling

    2010-02-04

    A pseudo-testcross pedigree is widely used for mapping quantitative trait loci (QTL) in outcrossing species, but the model for analyzing pseudo-testcross data borrowed from the inbred backcross design can only detect those QTLs that are heterozygous only in one parent. In this study, an intercross model that incorporates the high heterozygosity and phase uncertainty of outcrossing species was used to reanalyze a published data set on QTL mapping in poplar trees. Several intercross QTLs that are heterozygous in both parents were detected, which are responsible not only for biomass traits, but also for their genetic correlations. This study provides a more complete identification of QTLs responsible for economically important biomass traits in poplars.

  2. Post-treatment mechanical refining as a method to improve overall sugar recovery of steam pretreated hybrid poplar.

    PubMed

    Dou, Chang; Ewanick, Shannon; Bura, Renata; Gustafson, Rick

    2016-05-01

    This study investigates the effect of mechanical refining to improve the sugar yield from biomass processed under a wide range of steam pretreatment conditions. Hybrid poplar chips were steam pretreated using six different conditions with or without SO2. The resulting water insoluble fractions were subjected to mechanical refining. After refining, poplar pretreated at 205°C for 10min without SO2 obtained a 32% improvement in enzymatic hydrolysis and achieved similar overall monomeric sugar recovery (539kg/tonne) to samples pretreated with SO2. Refining did not improve hydrolyzability of samples pretreated at more severe conditions, nor did it improve the overall sugar recovery. By maximizing overall sugar recovery, refining could partially decouple the pretreatment from other unit operations, and enable the use of low temperature, non-sulfur pretreatment conditions. The study demonstrates the possibility of using post-treatment refining to accommodate potential pretreatment process upsets without sacrificing sugar yields.

  3. Seasonal variation in the structure of red reflectance of leaves from yellow poplar, red oak, and red maple

    NASA Technical Reports Server (NTRS)

    Brakke, Thomas W.; Wergin, William P.; Erbe, Eric F.; Harnden, Joann M.

    1993-01-01

    The light scattered from leaves was measured as a function of view angle in the principal plane for yellow poplar, red oak, and red maple. The source was a parallel-polarized helium-neon laser. Yellow poplar leaves had the highest reflectance of the three species, which may have been due to its shorter palisade cells and more extensive spongy mesophyll. Prior to senescence, there was a significant decrease, but not total extinction, in the reflectance of the beam incident at 60 deg from nadir on the adaxial side of the leaves of all three species. Low-temperature SEM observations showed differences in the surface wax patterns among the three species but did not indicate a cause of the reflectance changes other than possibly the accumulation and aging of the wax.

  4. Overexpression of poplar wounding-inducible genes in Arabidopsis caused improved resistance against Helicoverpa armigera (Hübner) larvae

    PubMed Central

    Hu, Rongfeng; Wang, Jiehua; Ji, Yan; Song, Yingjin; Yang, Shaohui

    2012-01-01

    Four highly inducible genes of poplar trees, PtdKTI5, PtdWIN4, PtdPOP3 from hybrid poplar (Populus trichocarpa × P. deltoides) and PtKTI2 from trembling aspen (Populus tremuloides Michx.) have been individually transformed into Arabidopsis thaliana for overexpression. High transcriptional level of each transgene in transgenic Arabidopsis lines was confirmed by RT-PCR analysis. The development, body weight and survivorship of cotton bollworm (Helicoverpa armigera) fed on four types of transgenic Arabidopis plants were evaluated in the laboratory. Our data indicated that these four Populus defense-related genes exhibited various degree of insectital activity on larval and postlarval development of cotton bollworm and may be utilized for herbivore resistance improvement in plant genetic engineering. PMID:23226090

  5. Impact of elevated CO(2) and nitrogen fertilization on foliar elemental composition in a short rotation poplar plantation.

    PubMed

    Marinari, Sara; Calfapietra, Carlo; De Angelis, Paolo; Mugnozza, Giuseppe Scarascia; Grego, Stefano

    2007-06-01

    The experiment was carried out on a short rotation coppice culture of poplars (POP-EUROFACE, Central Italy), growing in a free air carbon dioxide enriched atmosphere (FACE). The specific objective of this work was to study whether elevated CO(2) and fertilization (two CO(2) treatments, elevated CO(2) and control, two N fertilization treatments, fertilized and unfertilized), as well as the interaction between treatments caused an unbalanced nutritional status of leaves in three poplar species (P. x euramericana, P. nigra and P. alba). Finally, we discuss the ecological implications of a possible change in foliar nutrients concentration. CO(2) enrichment reduced foliar nitrogen and increased the concentration of magnesium; whereas nitrogen fertilization had opposite effects on leaf nitrogen and magnesium concentrations. Moreover, the interaction between elevated CO(2) and N fertilization amplified some element unbalances such as the K/N-ratio.

  6. Feeding on poplar leaves by caterpillars potentiates foliar peroxidase action in their guts and increases plant resistance.

    PubMed

    Barbehenn, Raymond; Dukatz, Chris; Holt, Chris; Reese, Austin; Martiskainen, Olli; Salminen, Juha-Pekka; Yip, Lynn; Tran, Lan; Constabel, C Peter

    2010-12-01

    Peroxidases (PODs) are believed to act as induced and constitutive defenses in plants against leaf-feeding insects. However, little work has examined the mode of action of PODs against insects. Putative mechanisms include the production of potentially antinutritive and/or toxic semiquinone free radicals and quinones (from the oxidation of phenolics), as well as increased leaf toughness. In this study, transgenic hybrid poplar saplings (Populus tremula × Populus alba) overexpressing horseradish peroxidase (HRP) were produced to examine the impact of elevated HRP levels on the performance and gut biochemistry of Lymantria dispar caterpillars. HRP-overexpressing poplars were more resistant to L. dispar than wild-type (WT) poplars when the level of a phenolic substrate of HRP (chlorogenic acid) was increased, but only when leaves had prior feeding damage. Damaged (induced) leaves produced increased amounts of hydrogen peroxide, which was used by HRP to increase the production of semiquinone radicals in the midguts of larvae. The decreased growth rates of larvae that fed on induced HRP-overexpressing poplars resulted from post-ingestive mechanisms, consistent with the action of HRP in their midguts. The toughness of HRP-overexpressing leaves was not significantly greater than that of WT leaves, whether or not they were induced. When leaves were coated with ellagitannins, induced HRP leaves also produced elevated levels of semiquinone radicals in the midgut. Decreased larval performance on induced HRP leaves in this case was due to post-ingestive mechanisms as well as decreased consumption. The results of this study provide the first demonstration that a POD is able to oxidize phenolics within an insect herbivore's gut, and further clarifies the chemical conditions that must be present for PODs to function as antiherbivore defenses.

  7. Interaction between isoprene and ozone fluxes at ecosystem level in a poplar plantation and its impact at European level

    NASA Astrophysics Data System (ADS)

    Zenone, T.; Hendriks, C.; Brilli, F.; Gioli, B.; Portillo Estrada, M.; Schaap, M.; Ceulemans, R.

    2015-12-01

    The emissions of Biogenic volatile organic compounds (BVOCs) from vegetation, mainly in form of isoprenoids, play an important role in the tropospheric ozone (O3) formation. The potential large expansion of isoprene emitter species (e.g. poplar) as biofuels feedstock might impact the ground level O3 formation. Here we report the simultaneous observations, using the eddy covariance (EC) technique, of isoprene, O3 and CO2 fluxes in a short rotation coppice (SRC) of poplar. The impact of current poplar plantations and associated isoprene emissions on ground level ozone concentrations for Europe was evaluated using a chemistry transport model (CTM) LOTOS-EUROS. The isoprene fluxes showed a well-defined seasonal and daily cycle that mirrored with the stomata O3 uptake. The isoprene emission and the stomata O3 uptake showed significant statistical relationship especially at elevated temperature. Isoprene was characterized by a remarkable peak of emissions (e.g. 38 nmol m-2s-1) occurring for few days as a consequence of the rapid variation of the air and surface temperature. During these days the photosynthetic apparatus (i.e. the CO2 fluxes) and transpiration rates did not show significant variation while we did observe a variation of the energy exchange and a reduction of the bowen ratio. The response of isoprene emissions to ambient O3 concentration follows the common form of the hormetic dose-response curve with a considerable reduction of the isoprene emissions at [O3] > 80 ppbv indicating a potential damping effect of the O3 levels on isoprene. Under the current condition the impact of SRC plantations on ozone concentrations / formation is very limited in Europe. Our findings indicate that, even with future scenarios with more SRC, or conventional poplar plantations, the impact on Ozone formation is negligible.

  8. [Morphological analysis of transgenic tobacco plants expressing the PnEXPA3 gene of black poplar (Populus nigra)].

    PubMed

    Kuluev, B R; Safiullina, M G; Kniazev, A V; Chemeris, A V

    2013-01-01

    Transgenic tobacco plants overexpressing the PnEXPA3 gene of black poplar (Populus nigra), which encodes alpha-expansin, were obtained. The transgenic plants were characterized by increased size of epidermic and mesophyll cells of leaves. However, the size of leaves remained normal. Overexpression of the PnEXPA3 gene provided stimulatory effect only on the stem length. Other morphological traits of the transgenic plants remained unchanged.

  9. Confirmatory Sampling and Analysis Plan for the Lower East Fork Poplar Creek Operable Unit, Oak Ridge, Tennessee

    SciTech Connect

    1996-12-01

    This document describes the organization, strategy, and procedures to be used to confirm that mercury concentrations in soils in the remediated areas are statistically less than, or equal to, the cleanup standard of 400 ppm. It focuses on confirming the cleanup of the stretch of the Lower East Fork Popular Creed flowing from Lake Reality at the Y-12 Plant, through the City of Oak Ridge, to Poplar Creek on the Oak Ridge Reservation and its associated flood plain.

  10. Towards a map of the Populus biomass protein-protein interaction network

    SciTech Connect

    Beers, Eric; Brunner, Amy; Helm, Richard; Dickerman, Allan

    2015-07-31

    Biofuels can be produced from a variety of plant feedstocks. The value of a particular feedstock for biofuels production depends in part on the degree of difficulty associated with the extraction of fermentable sugars from the plant biomass. The wood of trees is potentially a rich source fermentable sugars. However, the sugars in wood exist in a tightly cross-linked matrix of cellulose, hemicellulose, and lignin, making them largely recalcitrant to release and fermentation for biofuels production. Before breeders and genetic engineers can effectively develop plants with reduced recalcitrance to fermentation, it is necessary to gain a better understanding of the fundamental biology of the mechanisms responsible for wood formation. Regulatory, structural, and enzymatic proteins are required for the complicated process of wood formation. To function properly, proteins must interact with other proteins. Yet, very few of the protein-protein interactions necessary for wood formation are known. The main objectives of this project were to 1) identify new protein-protein interactions relevant to wood formation, and 2) perform in-depth characterizations of selected protein-protein interactions. To identify relevant protein-protein interactions, we cloned a set of approximately 400 genes that were highly expressed in the wood-forming tissue (known as secondary xylem) of poplar (Populus trichocarpa). We tested whether the proteins encoded by these biomass genes interacted with each other in a binary matrix design using the yeast two-hybrid (Y2H) method for protein-protein interaction discovery. We also tested a subset of the 400 biomass proteins for interactions with all proteins present in wood-forming tissue of poplar in a biomass library screen design using Y2H. Together, these two Y2H screens yielded over 270 interactions involving over 75 biomass proteins. For the second main objective we selected several interacting pairs or groups of interacting proteins for in

  11. Monitoring the effect of poplar trees on petroleum-hydrocarbon and chlorinated-solvent contaminated ground water

    USGS Publications Warehouse

    Landmeyer, J.E.

    2001-01-01

    At contaminated groundwater sites, poplar trees can be used to affect groundwater levels, flow directions, and ultimately total groundwater and contaminant flux to areas downgradient of the trees. The magnitude of the hydrologic changes can be monitored using fundamental concepts of groundwater hydrology, in addition to plant physiology-based approaches, and can be viewed as being almost independent of the contaminant released. The affect of poplar trees on the fate of groundwater contaminants, however, is contaminant dependent. Some petroleum hydrocarbons or chlorinated solvents may be mineralized or transformed to innocuous compounds by rhizospheric bacteria associated with the tree roots, mineralized or transformed by plant tissues in the transpiration stream or leaves after uptake, or passively volatilized and rapidly dispersed or oxidized in the atmosphere. These processes also can be monitored using a combination of physiological- or geochemical-based field or laboratory approaches. When combined, such hydrologic and contaminant monitoring approaches can result in a more accurate assessment of the use of poplar trees to meet regulatory goals at contaminated groundwater sites, verify that these goals continue to be met in the future, and ultimately lead to a consensus on how the performance of plant-based remedial strategies (phytoremediation) is to be assessed.

  12. Characterisation of the willow phenylalanine ammonia-lyase (PAL) gene family reveals expression differences compared with poplar

    PubMed Central

    de Jong, Femke; Hanley, Steven J.; Beale, Michael H.; Karp, Angela

    2015-01-01

    Willow is an important biomass crop for the bioenergy industry, and therefore optimal growth with minimal effects of biotic and abiotic stress is essential. The phenylpropanoid pathway is responsible for the biosynthesis of not only lignin but also of flavonoids, condensed tannins, benzenoids and phenolic glycosides which all have a role in protecting the plant against biotic and abiotic stress. All products of the phenylpropanoid pathway are important for the healthy growth of short rotation cropping species such as willow. However, the phenylpropanoid pathway in willow remains largely uncharacterised. In the current study we identified and characterised five willow phenylalanine ammonia-lyase (PAL) genes, which encode enzymes that catalyse the deamination of l-phenylalanine to form trans-cinnamic acid, the entry point into the phenylpropanoid pathway. Willow PAL1, PAL2, PAL3 and PAL4 genes were orthologous to the poplar genes. However no orthologue of PAL5 appears to be present in willow. Moreover, two tandemly repeated PAL2 orthologues were identified in a single contig. Willow PALs show similar sub-cellular localisation to the poplar genes. However, the enzyme kinetics and gene expression of the willow PAL genes differed slightly, with willow PAL2 being more widely expressed than its poplar orthologues implying a wider role for PALs in the production of flavonoids, condensed tannins, benzenoids, and phenolic glycosides, in willow. PMID:26070140

  13. Development and Validation of Marker-Aided Selection Methods for Wood Property Traits in Loblolly Pine and Hybrid Poplar

    SciTech Connect

    Tuskan, G.A.

    2001-06-20

    Wood properties influence pulp and paper quality. Certainly, overall pulp yields are directly related to the cellulose content, changes in hemicellulose content are associated with changes in pulp cohesiveness, and pulping efficiency is related to lignin content. Despite the importance of wood properties on product quality, little progress has been made in improving such traits because current methods of assessing wood and fiber characteristics are time-consuming, expensive, and often imprecise. Genetic improvement of wood and fiber properties has been further hampered by the large size of trees, delayed reproductive maturity and long harvest cycles. Recent developments in molecular genetics will help overcome the physical, economic and biological constraints in assessing and improving wood properties. Genetic maps consisting of numerous molecular markers are now available for loblolly pine and hybrid poplar. Such markers/maps may be used as part of a marker-aided selection and breeding effort or to expedite the isolation and characterization of genes and/or promoters that directly control wood properties. The objectives of this project are: (1) to apply new and rapid analytical techniques for assessing component wood properties to segregating F2 progeny populations of loblolly pine and hybrid poplar, (2) to map quantitative trait loci and identify molecular markers associated with wood properties in each of the above species and (3) to validate marker-aided selection methods for wood properties in loblolly pine and hybrid poplar.

  14. Characterisation of the willow phenylalanine ammonia-lyase (PAL) gene family reveals expression differences compared with poplar.

    PubMed

    de Jong, Femke; Hanley, Steven J; Beale, Michael H; Karp, Angela

    2015-09-01

    Willow is an important biomass crop for the bioenergy industry, and therefore optimal growth with minimal effects of biotic and abiotic stress is essential. The phenylpropanoid pathway is responsible for the biosynthesis of not only lignin but also of flavonoids, condensed tannins, benzenoids and phenolic glycosides which all have a role in protecting the plant against biotic and abiotic stress. All products of the phenylpropanoid pathway are important for the healthy growth of short rotation cropping species such as willow. However, the phenylpropanoid pathway in willow remains largely uncharacterised. In the current study we identified and characterised five willow phenylalanine ammonia-lyase (PAL) genes, which encode enzymes that catalyse the deamination of l-phenylalanine to form trans-cinnamic acid, the entry point into the phenylpropanoid pathway. Willow PAL1, PAL2, PAL3 and PAL4 genes were orthologous to the poplar genes. However no orthologue of PAL5 appears to be present in willow. Moreover, two tandemly repeated PAL2 orthologues were identified in a single contig. Willow PALs show similar sub-cellular localisation to the poplar genes. However, the enzyme kinetics and gene expression of the willow PAL genes differed slightly, with willow PAL2 being more widely expressed than its poplar orthologues implying a wider role for PALs in the production of flavonoids, condensed tannins, benzenoids, and phenolic glycosides, in willow.

  15. Molecular analysis of poplar defense against herbivory: comparison of wound- and insect elicitor-induced gene expression.

    PubMed

    Major, Ian T; Constabel, C Peter

    2006-01-01

    In order to characterize defense responses of hybrid poplar (Populus trichocarpax P. deltoides), we profiled leaf transcript patterns elicited by wounding and by regurgitant from forest tent caterpillar (FTC; Malacosoma disstria), a Lepidopteran defoliator of poplars. Macroarrays were used to compare transcript profiles. Both FTC-regurgitant (FTC-R) and mechanical wounding with pliers elicited expression of a variety of genes, and for these genes our analysis indicated that these treatments induced qualitatively similar responses. Similarly, a comparison of responses of directly treated and systemically induced leaves indicated extensive overlap in the sets of induced genes. FTC-R was found to contain the insect-derived elicitor volicitin. The simulated herbivory treatments resulted in the induction of genes involved in poplar defense and secondary metabolism. We also identified wound-responsive genes with roles in primary metabolism, including a putative invertase, lipase, and acyl-activating enzyme; some of these genes may have roles in defense signaling. In addition, we found three unknown genes containing a ZIM motif which may represent novel transcription factors.

  16. Determination of As in tree-rings of poplar (Populus alba L.) by U-shaped DC arc.

    PubMed

    Marković, D M; Novović, I; Vilotić, D; Ignjatović, Lj

    2009-04-01

    An argon-stabilized U-shaped DC arc with a system for aerosol introduction was used for determination of As in poplar (Populus alba L.) tree-rings. After optimization of the operating parameters and selection of the most appropriate signal integration time (30 s), the limit of detection for As was reduced to 15.0 ng/mL. This detection limit obtained with the optimal integration time was compared with those for other methods: inductively coupled plasma-atomic emission spectrometry (ICP-AES), direct coupled plasma-atomic emission spectrometry (DCP-AES), microwave induced plasma-atomic emission spectrometry (MIP-AES) and improved thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS). Arsenic is toxic trace element which can adversely affect plant, animal and human health. As an indicator of environment pollution we collected poplar tree-rings from two locations. The first area was close to the "Nikola Tesla" (TENT-A) power plant, Obrenovac, while the other was in the urban area of Novi Sad. In all cases elevated average concentrations of As were registered in poplar tree-rings from the Obrenovac location.

  17. Monitoring the effect of poplar trees on petroleum-hydrocarbon and chlorinated-solvent contaminated ground water

    USGS Publications Warehouse

    Landmeyer, James E.

    2001-01-01

    At contaminated groundwater sites, poplar trees can be used to affect ground-water levels, flow directions, and ultimately total groundwater and contaminant flux to areas downgradient of the trees. The magnitude of the hydrologic changes can be monitored using fundamental concepts of groundwater hydrology, in addition to plant physiology-based approaches, and can be viewed as being almost independent of the contaminant released. The affect of poplar trees on the fate of groundwater contaminants, however, is contaminant dependent. Some petroleum hydrocarbons or chlorinated solvents may be mineralized or transformed to innocuous compounds by rhizospheric bacteria associated with the tree roots, mineralized or transformed by plant tissues in the transpiration stream or leaves after uptake, or passively volatilized and rapidly dispersed or oxidized in the atmosphere. These processes also can be monitored using a combination of physiological- or geochemical-based field or laboratory approaches. When combined, such hydrologic and contaminant monitoring approaches can result in a more accurate assessment of the use of poplar trees to meet regulatory goals at contaminated groundwater sites, verify that these goals continue to be met in the future, and ultimately lead to a consensus on how the performance of plant-based remedial strategies (phytoremediation) is to be assessed.

  18. Quantifying the effect of nitrogen-induced physiological and structural changes on poplar growth using a carbon-balance model.

    PubMed

    Coll, Lluís; Schneider, Robert; Berninger, Frank; Domenicano, Susy; Messier, Christian

    2011-04-01

    We evaluate the importance of changes in photosynthetic capacity, respiration rates, root shoot ratio, pipe model parameters and specific leaf area in the early-growth response of hybrid poplar to nitrogen availability. Juvenile growth simulations for trees with three different levels of leaf nitrogen concentration (N(leaf)) (low (1.2%), medium (2.4%) and high (3.6%)) were conducted with the carbon-balance model CROBAS. Five-year growth simulations showed the diameter and height of poplar trees to be, respectively, four and three times larger in plants with 2.4% N(leaf) compared with those with 1.2% N(leaf). Increasing N(leaf) from 2.4 to 3.6% resulted in 34 and 16% higher diameter and height growth of trees. According to the model, changes in the photosynthetic capacity accounted for most of the differences in growth between trees with different levels of N(leaf); the other parameters were much less influential. This suggests that in fast-growing early-successional broadleaved species such as poplars, physiological rather than allocational and morphological traits predominate in determining growth, at least under non-limiting light conditions.

  19. Low temperatures are required to induce the development of fertile flowers in transgenic male and female early flowering poplar (Populus tremula L.).

    PubMed

    Hoenicka, Hans; Lehnhardt, Denise; Briones, Valentina; Nilsson, Ove; Fladung, Matthias

    2016-05-01

    Until now, artificial early flowering poplar systems have mostly led to the development of sterile flowers. In this study, several strategies aimed at inducting fertile flowers in pHSP::AtFT transgenic poplar were evaluated, in particular the influence of temperature and photoperiod. Our results provide evidence that temperature, and not photoperiod, is the key factor required for the development of fertile flowers in early flowering poplar. Fertile flowers were only obtained when a cold treatment phase of several weeks was used after the heat treatment phase. Heat treatments induced AtFT gene activity through activation of the heat-shock promoter (pHSP). Photoperiod did not show a similar influence on flower fertility as pollen grains were obtained under both long- and short-day conditions. Fertility was confirmed in flowers of both male and female plants. For the first time, crosses were successfully performed with transgenic female early flowering poplar. All mature flowers obtained after 8 weeks of inductive treatments were fertile. Gene expression studies also confirmed that cold temperatures influenced expression of poplar genes homologous to 'pollen development genes' from Arabidopsis thaliana (L.) Heynh. Homology and expression patterns suggested a role for PtTDF1, PtBAM1, PtSERK1/2 and PtMS1 on anther and pollen development in poplar flowers. The system developed in this study allows a fast and very reliable induction of fertile poplar flowers in a very short period of time. The non-reproductive phase, usually 7-10 years, can now be shortened to 6-10 months, and fertile flowers can be obtained independently of the season. This system is a reliable tool for breeding purposes (high-speed breeding technology), genomics and biosafety research.

  20. GENOME ENABLED MODIFICATION OF POPLAR ROOT DEVELOPMENT FOR INCREASED CARBON SEQUESTRATION

    SciTech Connect

    Busov, Victor

    2013-03-05

    DR5 as a reporter system to study auxin response in Populus Plant Cell Reports 32:453-463 Auxin responsive promoter DR5 reporter system is functional in Populus to monitor auxin response in tissues including leaves, roots, and stems. We described the behavior of the DR5::GUS reporter system in stably transformed Populus plants. We found several similarities with Arabidopsis, including sensitivity to native and synthetic auxins, rapid induction after treatment in a variety of tissues, and maximal responses in root tissues. There were also several important differences from Arabidopsis, including slower time to maximum response and lower induction amplitude. Young leaves and stem sections below the apex showed much higher DR5 activity than did older leaves and stems undergoing secondary growth. DR5 activity was highest in cortex, suggesting high levels of auxin concentration and/or sensitivity in this tissue. Our study shows that the DR5 reporter system is a sensitive and facile system for monitoring auxin responses and distribution at cellular resolution in poplar. The Populus AINTEGUMENTA LIKE 1 homeotic transcription factor PtAIL1 controls the formation of adventitious root primordia. Plant Physiol. 160: 1996-2006 Adventitious rooting is an essential but sometimes rate-limiting step in the clonal multiplication of elite tree germplasm, because the ability to form roots declines rapidly with age in mature adult plant tissues. In spite of the importance of adventitious rooting, the mechanism behind this developmental process remains poorly understood. We have described the transcriptional profiles that are associated with the developmental stages of adventitious root formation in the model tree poplar (Populus trichocarpa). Transcriptome analyses indicate a highly specific temporal induction of the AINTEGUMENTA LIKE1 (PtAIL1) transcription factor of the AP2 family during adventitious root formation. Transgenic poplar samples that overexpressed PtAIL1 were able to

  1. Canopy conductance of a high density poplar stand in Czech-Moravian Highlands

    NASA Astrophysics Data System (ADS)

    Fischer, Milan; Trnka, Miroslav; Orság, Matěj; Kučera, Jiří; Urban, Josef; Žalud, Zdeněk

    2013-04-01

    One of the most widely used approaches for modelling evapotranspiration is based on the Penman-Monteith concept. Within the frame of this analytical approach, canopy conductance remains the only variable which has to be predicted. In order to upscale the results of water use from bioenergy poplar plantations at the locality Domanínek in Czech-Moravian Highlands (49° 31´ N, 16° 14´ E and altitude 530 m a.s.l.) to different environmental conditions, we investigated the canopy conductance based on Bowen ratio energy balance measurements and its dependency on the basic meteorological and ecophysiological variables during 2008-2012. The plantation within the scope of this study is a monoclonal (Populus nigra x P. maximowiczii) high density stand with an area close to 3 ha. It was established in 2002 and the first harvest was carried out during the winter 2009/2010. The canopy conductance was strongly related to the leaf area index and thus showed typical seasonal patterns with the highest values in summer. The daily medians varied mostly within the range of 10 to 20 mm/s. In August 2012 when a pronounced drought stress has occurred, the daily medians of the canopy conductance decreased below 5 mm/s. Thus, apart from the leaf area index, the soil water availability was the most important predictor of the canopy conductance from the long term point of view (weeks or months). During the course of day, the canopy conductance can be well explained by nonlinear decreasing with increasing vapour pressure deficit and by increasing with the global radiation according to so called Lohammar model. In average, during the nearly light saturated periods (global radiation higher than 500 W/m2) the canopy conductance decreased from 23 mm/s through 12 mm/s to 6 mm/s for vapour pressure deficits 0.5, 1, and 2 kPa, respectively. By comparing the canopy conductance to the aerodynamic conductance, so called de-coupling factor (0-1) can be calculated. This factor ranged typically

  2. Biosafety and colonization of Burkholderia multivorans WS-FJ9 and its growth-promoting effects on poplars.

    PubMed

    Li, Guan-Xi; Wu, Xiao-Qin; Ye, Jian-Ren

    2013-12-01

    Burkholderia cepacia complex (Bcc) is a group of bacteria with conflicting biological characteristics, which make them simultaneously beneficial and harmful to humans. They have been exploited for biocontrol, bioremediation, and plant growth promotion. However, their capacity as opportunistic bacteria that infect humans restricts their biotechnological applications. Therefore, the risks of using these bacteria should be assessed. In this study, Burkholderia multivorans WS-FJ9 originally isolated from pine rhizosphere, which was shown to be efficient in solubilizing phosphate, was evaluated with respect to its biosafety, colonization in poplar rhizosphere, and growth-promoting effects on poplar seedlings. Pathogenicity of B. multivorans WS-FJ9 on plants was determined experimentally using onion and tobacco as model plants. Onion bulb inoculated with B. multivorans WS-FJ9 showed slight hypersensitive responses around the inoculation points, but effects were not detectable based on the inner color and odor of the onion. Tobacco leaves inoculated with B. multivorans WS-FJ9 exhibited slightly water-soaked spots around the inoculation points, which did not expand or develop into lesions even with repeated incubation. Pathogenicity of the strain in alfalfa, which has been suggested as an alternative Bcc model for mice, was not detectable. Results from gene-specific polymerase chain reactions showed that the tested B. multivorans WS-FJ9 strain did not possess the BCESM and cblA virulence genes. Scanning electron microscopy revealed that the colonization of the WS-FJ9 strain reached 1.4 × 10(4) colony forming units (cfu) g(-1) rhizosphere soil on day 77 post-inoculation. The B. multivorans WS-FJ9 strain could colonize the rhizosphere as well as the root tissues and cells of poplars. Greenhouse evaluations in both sterilized and non-sterilized soils indicated that B. multivorans WS-FJ9 significantly promoted growth in height, root collar diameter, and plant biomass of

  3. Plant feedbacks on soil respiration in a poplar plantation under elevated CO2 and nitrogen fertilization

    NASA Astrophysics Data System (ADS)

    Lagomarsino, Alessandra; Lukac, Martin; Godbold, Douglas L.; Marinari, Sara; de Angelis, Paolo

    2010-05-01

    FACE experiments offered a unique occasion to investigate plant-soil relationship in terrestrial ecosystems. Changes in plant productivity and carbon (C) allocation under elevated CO2 have the potential to alter soil processes mediated by microorganisms. Also, fertilization can strongly affect plant-soil relationships through both direct and indirect effects. A fast growing poplar plantation was treated for six consecutive years with elevated CO2 at two nitrogen (N) levels. In the frame of plant responses to these environmental factors, our intent is to investigate plant-soil relationships and their impact on soil CO2 emissions. In particular, feedbacks of root productivity on soil respiration and heterotrophic community have been assessed in the last two years of the field experiment. In the POP-EUROFACE fast growing poplar plantation, the enhancement of atmospheric CO2 concentration induced an increase of fine root biomass and productivity, and consequently rhizodeposition. Concurrently, N addition reduced total root biomass but did not affect productivity. Soil respiration was deeply impacted by elevated CO2, with increases up to 95%, independent of N availability. The increase involved both auto and rhizomicrobial components of soil respiration. Indeed, the root-rhizosphere continuum stimulated the rhizomicrobial respiration, with the prompt loss of part of the extra C fixed through photosynthesis in elevated CO2. In fact, whereas the basal soil respiration was significantly dependent on fine root standing biomass, total soil respiration and the rhizomicrobial component during the growing season were significantly dependent on fine root productivity. This mechanism was also evident in the year following the end of CO2 enrichment, when no "residual" effects of elevated CO2 on soil respiration were observed, in unfertilized soil. The relationship between root productivity and heterotrophic respiration was mediated by the pattern of labile C availability in soil

  4. Rhizosphere carbon deposition, oxidative stress and nutritional changes in two poplar species exposed to aluminum.

    PubMed

    Naik, Dhiraj; Smith, Ernest; Cumming, Jonathan R

    2009-03-01

    Species and hybrids in the genus Populus have become the focus of investigation for use in biofuels production and their capacity to sequester carbon (C) in the environment. The identification of species resistant to marginal edaphic sites may be important in both of these endeavors. Plant growth, total dissolved organic carbon (TOC) and low molecular weight organic acid (OA) production, antioxidative enzyme activities and mineral content were assessed in Populus tremuloides L. and Populus trichocarpa Torr. & Gray seedlings under exposure to aluminum (Al). Both species were sensitive to Al, with significant reductions in shoot and root biomass at and above 50 microM Al. Exposure to Al induced 40-fold increases in TOC deposition in P. tremuloides and 100-fold increases in P. trichocarpa. In P. tremuloides, Al treatment induced root exudation of malic and citric acids, while Al increased exudation of citrate and oxalate in P. trichocarpa. Organic acids accounted for 20-64% of total C released upon Al exposure, with the proportion of OAs increasing in P. tremuloides and decreasing in P. trichocarpa. Dose-dependent responses of catalase and ascorbate peroxidase were observed in both root and leaf tissues, indicating that Al exposure induced oxidative stress in poplar. Treatment at and above 100 microM Al reduced the concentrations of calcium (Ca) and magnesium (Mg) in roots and leaves, whereas Al at or above 50 microM reduced root and leaf phosphorous (P) concentrations. The majority of Al taken up was retained in the root system. Even with the induction of OA exudation and accumulation, P. tremuloides and P. trichocarpa remained sensitive to Al, as evidenced by elevated antioxidative enzyme activities, which may reflect inhibition of Ca or P uptake and destabilization of cell homeostasis in these poplar species. Although plants exhibited reductions in growth and evidence of oxidative and nutritional stress, total C rhizodeposition rates for both species increased with

  5. Greenhouse gas balance of cropland conversion to bioenergy poplar short rotation coppice

    NASA Astrophysics Data System (ADS)

    Sabbatini, S.; Arriga, N.; Bertolini, T.; Castaldi, S.; Chiti, T.; Consalvo, C.; Njakou Djomo, S.; Gioli, B.; Matteucci, G.; Papale, D.

    2015-05-01

    The production of bioenergy in Europe is one of the strategies conceived to reduce greenhouse gas (GHG) emissions. The suitability of the land use change from a cropland (REF site) to a short rotation coppice plantation of hybrid poplar (SRC site) was investigated by comparing the GHG budgets of these two systems over 24 months in Viterbo, Italy. Eddy covariance measurements were carried out to quantify the net ecosystem exchange of CO2 (FCO2), whereas chambers were used to measure N2O and CH4 emissions from soil. Soil organic carbon (SOC) of an older poplar plantation was used to estimate via a regression the SOC loss due to SRC establishment. Emissions from tractors and from production and transport of agricultural inputs (FMAN) were modelled and GHG emission offset due to fossil fuel substitution was credited to the SRC site considering the C intensity of natural gas. Emissions due to the use of the biomass (FEXP) were also considered. The suitability was finally assessed comparing the GHG budgets of the two sites. FCO2 was the higher flux in the SRC site (-3512 ± 224 g CO2 eq m-2 in two years), while in the REF site it was -1838 ± 107 g CO2 m-2 in two years. FEXP was equal to 1858 ± 240 g CO2 m-2 in 24 months in the REF site, thus basically compensating FCO2, while it was 1118 ± 521 g CO2 eq m-2 in 24 months in the SRC site. This latter could offset -379.7 ± 175.1 g CO2 eq m-2 from fossil fuel displacement. Soil CH4 and N2O fluxes were negligible. FMAN weighed 2 and 4% in the GHG budgets of SRC and REF sites respectively, while the SOC loss weighed 455 ± 524 g CO2 m-2 in two years. Overall, the REF site was close to neutrality in a GHG perspective (156 ± 264 g CO2 eq m-2), while the SRC site was a net sink of -2202 ± 792 g CO2 eq m-2. In conclusion the experiment led to a positive evaluation of the conversion of cropland to bioenergy SRC from a GHG viewpoint.

  6. Effect of drought on fine roots productivity in poplar-based short rotation coppice

    NASA Astrophysics Data System (ADS)

    Mani Tripathi, Abhishek; Fischer, Milan; Berhongaray, Gonzalo; Orság, Matěj; Trnka, Miroslav

    2015-04-01

    Short rotation woody crops (SRWC) are alternative source of bioenergy, which apart from their 'carbon neutrality' have potential to store carbon (C) into soil and mitigate the increasing CO2 emission. Studies of below ground biomass of trees are divided into two types according to root diameter - analysis of fine roots (less than 2 mm) and coarse roots (more than 2 mm). Trees roots are spatially highly heterogeneous and it requires large number of samples to obtain a representative estimate of belowground biomass. For this study we used hybrid poplar clone J-105 (Populus nigra x P. maximowiczii) grown under short rotation coppice system in the region of Bohemian-Moravian Highland (49o32'N, 16o15'E and altitude 530 m a.s.l.) since April 2000. The plantation with planting density of 9,216 trees ha-1 was established on the former agricultural land and the length of the rotation cycle was set to 6-8 years. While mean annual rainfall was 609 mm with mean annual temperature 7.2oC during 1981-2013 significant increase of temperature and more frequent droughts are expected. In 2011, we established drought experiment based on throughfall exclusion system, reducing up to 70 % of throughfall precipitation. Thus 2 treatments with normal and lowered soil moisture levels were introduced. In January and February 2014, we cored 18 places including drought and control using root bipartite auger. The main goal of the study is to assess the response of fine roots productivity and fine roots vertical distribution on the reduced soil water availability. Results will be presented at the conference. Acknowledgements: This study was funded by research project IGA Mendel University 2014 "Study of below ground biomass in short rotation poplar coppice (J-105) in the Czech-Moravian Highlands", project PASED (KONTAKT II LH12037 ʺDevelopment of models for the assessment of abiotic stresses in selected energy woody plantsʺ and "Building up a multidisciplinary scientific team focused on drought

  7. Expression and molecular evolution of two DREB1 genes in black poplar (Populus nigra).

    PubMed

    Chu, Yanguang; Huang, Qinjun; Zhang, Bingyu; Ding, Changjun; Su, Xiaohua

    2014-01-01

    Environmental stresses such as low temperature, drought, and high salinity significantly affect plant growth and yield. As selective forces, these adverse factors play essential roles in shaping phenotypic variation in plant populations. Black poplar (Populus nigra) is an economically and ecologically important forest tree species with widely distributed populations and is thus suitable for experiments detecting evolutionary footprints left by stress. Here, we performed expression and evolutionary analysis of two duplicated DREB A1-subgroup (DREB1) genes, PnDREB68 and PnDREB69, encoding transcription factors that are involved in stress responses. The two genes showed partially overlapping but distinct expression patterns in response to stresses. These genes were strongly and rapidly induced by cold stress in leaves, stems, and roots. In leaf tissue, dehydration stress induced the expression of PnDREB68 but not PnDREB69. PnDREB69 displayed more rapid responses and longer expression durations than PnDREB68 under salt and ABA stress, respectively. Based on single nucleotide polymorphism (SNP) analysis, we found significant population genetic differentiation, with a greater FST value (0.09189) for PnDREB69 than for PnDREB68 (0.07743). Nucleotide diversity analysis revealed a two-fold higher πT for PnDREB68 than for PnDREB69 (0.00563 vs. 0.00243), reflecting strong purifying selection acting on the former. The results suggest that positive selection acted on PnDREB69, as evidenced by neutral testing using Tajima's D statistic. The distinct selective forces to which each of the genes was subjected may be associated with expression divergence. Linkage disequilibrium (LD) was low for the sequenced region, with a higher level for PnDREB68 than for PnDREB69. Additionally, analysis of the relationship among carbon isotope ratios, SNP classes and gene expression, together with motif and domain analysis, suggested that 14 polymorphisms within the two genes may be candidates

  8. Emissions of volatile organic compounds from hybrid poplar depend on CO2 concentration and genotype

    NASA Astrophysics Data System (ADS)

    Eller, A. S.; de Gouw, J. A.; Monson, R. K.

    2010-12-01

    Hybrid poplar is a fast-growing tree species that is likely to be an important source of biomass for the production of cellulose-based biofuels and may influence regional atmospheric chemistry through the emission of volatile organic compounds (VOCs). We used proton-transfer reaction mass spectrometry to measure VOC emissions from the leaves of four different hybrid poplar genotypes grown under ambient (400 ppm) and elevated (650 ppm) carbon dioxide concentration (CO2). The purpose of this experiment was to determine whether VOC emissions are different among genotypes and whether these emissions are likely to change as atmospheric CO2 rises. Methanol and isoprene made up over 90% of the VOC emissions and were strongly dependent on leaf age, with young leaves producing primarily methanol and switching to isoprene production as they matured. Monoterpene emissions were small, but tended to be higher in young leaves. Plants grown under elevated CO2 emitted smaller quantities of both methanol and isoprene, but the magnitude of the effect was dependent on genotype. Isoprene emission rates from mature leaves dropped from ~35 to ~28 nmol m-2 s-1 when plants were grown under elevated CO2. Emissions from individuals grown under ambient CO2 varied more based on genotype than those grown under elevated CO2, which means that we might expect smaller differences between genotypes in the future. Genotype and CO2 also affected how much carbon (C) individuals allocated to the production of VOCs. The emission rate of C from VOCs was 0.5 - 2% of the rate at which C was assimilated via net photosynthesis. The % C emitted was strongly related to genotype; clones from crosses between Populus deltoides and P. trichocarpa (T x D) allocated a greater % of their C to VOC emissions than clones from crosses of P. deltoids and P. nigra (D x N). Individuals from all four genotypes allocated a smaller % of their C to the emission of VOCs when they were grown under elevated CO2. These results

  9. Greenhouse gas balance of cropland conversion to bioenergy poplar short-rotation coppice

    NASA Astrophysics Data System (ADS)

    Sabbatini, S.; Arriga, N.; Bertolini, T.; Castaldi, S.; Chiti, T.; Consalvo, C.; Njakou Djomo, S.; Gioli, B.; Matteucci, G.; Papale, D.

    2016-01-01

    The production of bioenergy in Europe is one of the strategies conceived to reduce greenhouse gas (GHG) emissions. The suitability of the land use change from a cropland (REF site) to a short-rotation coppice plantation of hybrid poplar (SRC site) was investigated by comparing the GHG budgets of these two systems over 24 months in Viterbo, Italy. This period corresponded to a single rotation of the SRC site. The REF site was a crop rotation between grassland and winter wheat, i.e. the same management of the SRC site before the conversion to short-rotation coppice. Eddy covariance measurements were carried out to quantify the net ecosystem exchange of CO2 (FCO2), whereas chambers were used to measure N2O and CH4 emissions from soil. The measurements began 2 years after the conversion of arable land to SRC so that an older poplar plantation was used to estimate the soil organic carbon (SOC) loss due to SRC establishment and to estimate SOC recovery over time. Emissions from tractors and from production and transport of agricultural inputs (FMAN) were modelled. A GHG emission offset, due to the substitution of natural gas with SRC biomass, was credited to the GHG budget of the SRC site. Emissions generated by the use of biomass (FEXP) were also considered. Suitability was finally assessed by comparing the GHG budgets of the two sites. CO2 uptake was 3512 ± 224 g CO2 m-2 at the SRC site in 2 years, and 1838 ± 107 g CO2 m-2 at the REF site. FEXP was equal to 1858 ± 240 g CO2 m-2 at the REF site, thus basically compensating for FCO2, while it was 1118 ± 521 g CO2 m-2 at the SRC site. The SRC site could offset 379.7 ± 175.1 g CO2eq m-2 from fossil fuel displacement. Soil CH4 and N2O fluxes were negligible. FMAN made up 2 and 4 % in the GHG budgets of SRC and REF sites respectively, while the SOC loss was 455 ± 524 g CO2 m-2 in 2 years. Overall, the REF site was close to neutrality from a GHG perspective (156 ± 264 g CO2eq m-2), while the SRC site was a net sink of

  10. Investigation on effect of Populus alba stands distance on density of pests and their natural enemies population under poplar/alfalfa agroforestry system.

    PubMed

    Khabir, Z H; Sadeghi, S E; Hanifeh, S; Eivazi, A

    2009-01-15

    This study was carried out in order to distinguish the effect of agroforestry system (combination of agriculture and forestry) on pests and natural enemy's population in poplar research station. Wood is one of the first substances that naturally was used for a long period of time. Forage is an important production of natural resources too. Some factors such as proper lands deficit, lack of economy, pest and disease attacks and faced production of these materials with serious challenges. Agroforestry is a method for decrease of the mentioned problems. The stands of poplar had have planted by complete randomized design with 4 treatments (stand distance) of poplar/alfalfa include 3x4, 3x6.7, 3x8, 3x10 m and 2 control treatments, alfalfa and poplar. The results showed that Chaitophorus populeti had the highest density in poplar and 3x10 m treatments. Monosteira unicostata is another insect pest that had most density in 3x10 m treatment. And alfalfa had high density of Chrysoperla carnea. The density of Coccinella septempunctata, were almost equal in all treatments.

  11. Design of experiments on 135 cloned poplar trees to map environmental influence in greenhouse.

    PubMed

    Pinto, Rui Climaco; Stenlund, Hans; Hertzberg, Magnus; Lundstedt, Torbjörn; Johansson, Erik; Trygg, Johan

    2011-01-31

    To find and ascertain phenotypic differences, minimal variation between biological replicates is always desired. Variation between the replicates can originate from genetic transformation but also from environmental effects in the greenhouse. Design of experiments (DoE) has been used in field trials for many years and proven its value but is underused within functional genomics including greenhouse experiments. We propose a strategy to estimate the effect of environmental factors with the ultimate goal of minimizing variation between biological replicates, based on DoE. DoE can be analyzed in many ways. We present a graphical solution together with solutions based on classical statistics as well as the newly developed OPLS methodology. In this study, we used DoE to evaluate the influence of plant specific factors (plant size, shoot type, plant quality, and amount of fertilizer) and rotation of plant positions on height and section area of 135 cloned wild type poplar trees grown in the greenhouse. Statistical analysis revealed that plant position was the main contributor to variability among biological replicates and applying a plant rotation scheme could reduce this variation.

  12. Pyrolysis polygeneration of poplar wood: Effect of heating rate and pyrolysis temperature.

    PubMed

    Chen, Dengyu; Li, Yanjun; Cen, Kehui; Luo, Min; Li, Hongyan; Lu, Bin

    2016-10-01

    The pyrolysis of poplar wood were comprehensively investigated at different pyrolysis temperatures (400, 450, 500, 550, and 600°C) and at different heating rates (10, 30, and 50°C/min). The results showed that BET surface area of biochar, the HHV of non-condensable gas and bio-oil reached the maximum values of 411.06m(2)/g, 14.56MJ/m(3), and 14.39MJ/kg, under the condition of 600°C and 30°C/min, 600°C and 50°C/min, and 550°C and 50°C/min, respectively. It was conducive to obtain high mass and energy yield of bio-oil at 500°C and higher heating rate, while lower pyrolysis temperature and heating rate contributed towards obtaining both higher mass yield and energy yield of biochar. However, higher pyrolysis temperature and heating rate contributed to obtain both higher mass yield and energy yield of the non-condensable gas. In general, compared to the heating rate, the pyrolysis temperature had more effect on the product properties.

  13. Uptake of trichloroethylene by hybrid poplar trees grown hydroponically in flow-through plant growth chambers

    SciTech Connect

    Orchard, B.J.; Doucette, W.J.; Chard, J.K.; Bugbee, B.

    2000-04-01

    Phytoremediation in being promoted as a cost-effective treatment option for shallow groundwater and soils contaminated with trichloroethylene (TCE). However, its effectiveness is difficult to assess due to contradictory reports regarding the magnitude of plant uptake and phytovolatilization. Experimental artifacts and plants stress, resulting from the use of static or low-flow plants growth laboratory systems, may account for part of the discrepancy. High exposure concentrations and short durations may also cause artifacts in laboratory studies. A dual-chamber plant growth system designed to minimize experimental artifacts was used to determine the uptake of [{sup 14}C] TCE by hydroponically grown hybrid poplar as a function of plant stress, exposure concentration, and exposure duration. The [{sup 14}]TCE recoveries ranged from 92 to 101% in 11 dosed chambers. Trichloroethylene mass equivalent concentrations in the shoot tissue were dependent on the amount of water transpired and the exposure concentration. Root-zone oxygen status die not significantly impact TCE uptake. Transpiration stream concentration factors (TSCFs) determined in these studies were independent of exposure duration and are much lower than those previously reported and predicted. The role of TSCF and other factors in estimating the significance of plant uptake in the phytoremediation of TCE-contaminated groundwater is discussed.

  14. Ionic liquid pretreatment of poplar wood at room temperature: swelling and incorporation of nanoparticles.

    PubMed

    Lucas, Marcel; Macdonald, Brian A; Wagner, Gregory L; Joyce, Stephen A; Rector, Kirk D

    2010-08-01

    Lignocellulosic biomass offers economic and environmental advantages over corn starch for biofuels production. However, its fractionation currently requires energy-intensive pretreatments, due to the lignin chemical resistance and complex cell wall structure. Recently, ionic liquids have been used to dissolve biomass at high temperatures. In this study, thin sections of poplar wood were swollen by ionic liquid (1-ethyl-3-methylimidazolium acetate) pretreatment at room temperature. The samples contract when rinsed with deionized water. The controlled expansion and contraction of the wood structure can be used to incorporate enzymes and catalysts deep into the wood structure for improved pretreatments and accelerated cellulose hydrolysis. As a proof of concept, silver and gold nanoparticles of diameters ranging from 20 to 100 nm were incorporated at depths up to 4 mum. Confocal surface-enhanced Raman images at different depths show that a significant number of nanoparticles were incorporated into the pretreated sample, and they remained on the samples after rinsing. Quantitative X-ray fluorescence microanalyses indicate that the majority of nanoparticle incorporation occurs after an ionic liquid pretreatment of less than 1 h. In addition to improved pretreatments, the incorporation of materials and chemicals into wood and paper products enables isotope tracing, development of new sensing, and imaging capabilities.

  15. Structural Transformation of Isolated Poplar and Switchgrass Lignins from Dilute Acid Pretreatment

    SciTech Connect

    Sun, Qining; Pu, Yunqiao; Meng, Xianzhi; Wells, Tyrone; Ragauskas, Arthur J.

    2015-08-27

    A key step in conversion of cellulosic biomass into sustainable fuels and chemicals is thermochemical pretreatment to reduce plant cell wall recalcitrance. Obtaining an improved understanding of the fundamental chemistry of lignin, the most recalcitrant component of biomass, during pretreatment is critical to the continued development of renewable biofuel production. To examine the intrinsic chemistry of lignin during dilute acid pretreatment (DAP), lignin was isolated from poplar and switchgrass using a cellulolytic enzyme system and then treated under DAP conditions. These results highlight that lignin is subjected to depolymerization reactions within the first 2 min of dilute acid pretreatment and these changes are accompanied by increased generation of aliphatic and phenolic hydroxyl groups of lignin. This is followed by a competing set of depolymerization and repolymerization reactions that lead to a decrease in the content of guaiacyl lignin units and an increase in condensed lignin units as the reaction residence time is extended beyond 5 min. Finally, we showed that a detailed comparison of changes in functional groups and molecular weights of cellulolytic enzyme lignins with different structural parameters, related to the recalcitrant properties of lignin, could be successfully altered during DAP conditions.

  16. Remediation of polycyclic aromatic hydrocarbon compounds in groundwater using poplar trees.

    PubMed

    Widdowson, Mark A; Shearer, Sandra; Andersen, Rikke G; Novak, John T

    2005-03-15

    A seven-year study was conducted to assess the effectiveness of hybrid poplar trees to remediate polycyclic aromatic hydrocarbon (PAH) compounds in soil and groundwater at a creosote-contaminated site. A reduction in the areal extent of the PAH plume was observed in the upper half of the 2-m-thick saturated zone, and PAH concentration levels in the groundwater declined throughout the plume. PAH concentrations began to decline during the period between the third and fourth growing seasons, which coincided with the propagation of the tree roots to the water table region. Remediation was limited to naphthalene and several three-ring PAHs (acenaphthylene and acenaphthene). PAH concentrations in soil and aquifer sediment samples also declined over time; however, levels of four-ring PAHs persisted at the lower depths during the study period. The naphthalene to total PAH concentration ratio in the most contaminated groundwater decreased from >0.90 at the beginning of the second growing season to approximately 0.70 at the end the study. Remediation in the lower region of the saturated zone was limited bythe presence of a 0.3-m-thick layer of creosote present as a dense nonaqueous phase liquid (DNAPL). The nearly steady-state condition of the PAH concentrations observed during the last three years of the study suggests that the effectiveness of the phytoremediation system is limited by the rate of PAH dissolution from the DNAPL source.

  17. Defining hybrid poplar (Populus deltoides x Populus trichocarpa) tolerance to ozone: identifying key parameters.

    PubMed

    Ryan, A; Cojocariu, C; Possell, M; Davies, W J; Hewitt, C N

    2009-01-01

    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 isoprene protects plants against oxidative stress. Therefore, it was hypothesized that these two genotypes would differ in either their basal isoprene emission rates or in the response of isoprene to fumigation by ozone. Our results showed that the basal emission rates of isoprene, physiological responses and ozone uptake rates were all similar. However, significant differences were found in visible damage, carotenoids, hydrogen peroxide (H(2)O(2)), thiobarbituric acid reactions (TBARS) and post-fumigation isoprene emission rates. It is shown that, although the classification of ozone tolerance or sensitivity had been previously clearly and carefully defined using one particular set of parameters, assessment of other key variables does not necessarily lead to the same conclusions. Thus, it may be necessary to reconsider the way in which plants are classified as ozone tolerant or sensitive.

  18. Physiology and Thermal Imaging of Poplar Hybrids with Varying Temperature Tolerance

    NASA Astrophysics Data System (ADS)

    Ibsen, P.; Van Leeuwen, W. J. D.; McCorkel, J.; Barron-Gafford, G.; Moore, D. J.

    2014-12-01

    : Plants growing in high temperatures may suffer from reduced photosynthetic efficiency, increased water demand and thermal damage to tissue. Leaves may mitigate heat stress through physiological or physical strategies which include minimizing heat load, maximizing evaporative cooling or biochemical stabilization. In this study, leaf temperature of wild-type and genetically modified (GM) poplar trees was monitored using a thermal infrared camera and fine wire thermocouples. The GM trees did not have the capacity to produce the compound isoprene, hypothesized to biochemically protect plants against heat stress. One genotype had GM process applied, but retained isoprene making capacity (empty-vector). Temperature of ambient air and of an artificial leaf of similar size/color were also monitored. Photosynthesis and transpiration were measured using an infra-red gas analyzer. Leaf reflectance in an integrating sphere was determined using a spectrometer. Leaf temperature was maintained close to or below air temperature and was always lower than the fake (non-transpiring leaf). Different genetic lines maintained different leaf temperatures, especially during peak temperature in the mid afternoon. The variance in leaf temperature is explored in relation to its effects on transpiration, photosynthesis and growth across isoprene and non-isoprene emitting trees.

  19. Enhanced salt tolerance of transgenic poplar plants expressing a manganese superoxide dismutase from Tamarix androssowii.

    PubMed

    Wang, Yu Cheng; Qu, Guan Zheng; Li, Hong Yan; Wu, Ying Jie; Wang, Chao; Liu, Gui Feng; Yang, Chuan Ping

    2010-02-01

    Superoxide dismutases (SODs) play important role in stress tolerance of plants. In this study, an MnSOD gene (TaMnSOD) from Tamarix androssowii, under the control of the CaMV35S promoter, was introduced into poplar (Populus davidiana x P. bolleana). The physiological parameters, including SOD activity, malondialdehyde (MDA) content, relative electrical conductivity (REC) and relative weight gain, of transgenic lines and wild type (WT) plants, were measured and compared. The results showed that SOD activity was enhanced in transgenic plants, and the MDA content and REC were significantly decreased compared to WT plants when exposed to NaCl stress. In addition, the relative weight gains of the transgenic plants were 8- to 23-fold of those observed for WT plants after NaCl stress for 30 days. The data showed that the SOD activities that increased in transgenic lines are 1.3-4-folds of that increased in the WT plant when exposed to NaCl stress. Our analysis showed that increases in SOD activities as low as 0.15-fold can also significantly enhance salt tolerance in transgenic plants, suggesting an important role of increased SOD activity in plant salt tolerance

  20. Water extraction kinetics of metals, arsenic and dissolved organic carbon from industrial contaminated poplar leaves.

    PubMed

    Shahid, Muhammad; Xiong, Tiantian; Castrec-Rouelle, Maryse; Leveque, Tibo; Dumat, Camille

    2013-12-01

    In industrial areas, tree leaves contaminated by metals and metalloids could constitute a secondary source of pollutants. In the present study, water extraction kinetics of inorganic elements (IE: Pb, Zn, Cd, As, Fe and Mn), dissolved organic carbon, pH and biological activity were studied for industrial contaminated poplar leaves. Moreover, the distribution of the IE through the size fractions of the associated top soil was measured. High quantities of Mn, Zn and As and polysaccharides were released in the solution from the strongly contaminated leaves. The kinetic of release varied with time and metal type. The solution pH decreased while dissolved organic contents increased with time after 30 days. Therefore, these contaminated leaves could constitute a source of more available organic metals and metalloids than the initial inorganic process particles. However, the distribution of the IE through the size fractions of the top soil suggested that a great part of the released IE was adsorbed, reducing in consequence their transfers and bioavailability. It's concluded that mobility/bioavailability and speciation of metals and metalloids released from the decomposition of polluted tree leaves depends on soil characteristics, pollutant type and litter composition, with consequences for environmental risk assessment.

  1. Enhanced delignification of steam-pretreated poplar by a bacterial laccase

    PubMed Central

    Singh, Rahul; Hu, Jinguang; Regner, Matthew R.; Round, James W.; Ralph, John; Saddler, John N.; Eltis, Lindsay D.

    2017-01-01

    The recalcitrance of woody biomass, particularly its lignin component, hinders its sustainable transformation to fuels and biomaterials. Although the recent discovery of several bacterial ligninases promises the development of novel biocatalysts, these enzymes have largely been characterized using model substrates: direct evidence for their action on biomass is lacking. Herein, we report the delignification of woody biomass by a small laccase (sLac) from Amycolatopsis sp. 75iv3. Incubation of steam-pretreated poplar (SPP) with sLac enhanced the release of acid-precipitable polymeric lignin (APPL) by ~6-fold, and reduced the amount of acid-soluble lignin by ~15%. NMR spectrometry revealed that the APPL was significantly syringyl-enriched relative to the original material (~16:1 vs. ~3:1), and that sLac preferentially oxidized syringyl units and altered interunit linkage distributions. sLac’s substrate preference among monoaryls was also consistent with this observation. In addition, sLac treatment reduced the molar mass of the APPL by over 50%, as determined by gel-permeation chromatography coupled with multi-angle light scattering. Finally, sLac acted synergistically with a commercial cellulase cocktail to increase glucose production from SPP ~8%. Overall, this study establishes the lignolytic activity of sLac on woody biomass and highlights the biocatalytic potential of bacterial enzymes. PMID:28169340

  2. Enhanced delignification of steam-pretreated poplar by a bacterial laccase

    DOE PAGES

    Singh, Rahul; Hu, Jinguang; Regner, Matthew R.; ...

    2017-02-07

    The recalcitrance of woody biomass, particularly its lignin component, hinders its sustainable transformation to fuels and biomaterials. Although the recent discovery of several bacterial ligninases promises the development of novel biocatalysts, these enzymes have largely been characterized using model substrates: direct evidence for their action on biomass is lacking. Herein, we report the delignification of woody biomass by a small laccase (sLac) from Amycolatopsis sp. 75iv3. Incubation of steam-pretreated poplar (SPP) with sLac enhanced the release of acid-precipitable polymeric lignin (APPL) by ~6-fold, and reduced the amount of acid-soluble lignin by ~15%. NMR spectrometry revealed that the APPL was significantlymore » syringyl-enriched relative to the original material (~16:1 vs. ~3:1), and that sLac preferentially oxidized syringyl units and altered interunit linkage distributions. sLac’s substrate preference among monoaryls was also consistent with this observation. In addition, sLac treatment reduced the molar mass of the APPL by over 50%, as determined by gel-permeation chromatography coupled with multi-angle light scattering. Finally, sLac acted synergistically with a commercial cellulase cocktail to increase glucose production from SPP ~8%. Altogether, this study establishes the lignolytic activity of sLac on woody biomass and highlights the biocatalytic potential of bacterial enzymes.« less

  3. Poplar Island Environmental Restoration Project: Challenges in waterbird restoration on an island in Chesapeake Bay

    USGS Publications Warehouse

    Erwin, R.M.; Miller, J.; Reese, J.G.

    2007-01-01

    At 460 hectares, the Paul Sarbanes Environmental Restoration Project at Poplar Island, Talbot County, Maryland, represents the largest 'beneficial use' dredged material project of the U. S. Army Corps of Engineers (a cooperative project with Maryland Port Administration). Begun in 1998, the 15-year restoration project will ultimately consist of roughly 220 ha of uplands and 220 ha of tidal wetland habitats, with limited areas of dike roads, perimeter riprap, and unvegetated mudflats. Wetland restoration began in one small section (or 'cell') in 2002, but not all cells will be filled with dredged material until at least 2013. As a major objective of the restoration, six species of waterbirds were identified as 'priority species' for Chesapeake Bay: American black duck (Anas rubripes), snowy egret (Egretta thula), cattle egret (Bubulcus ibis), osprey (Pandion haliaetus), common tern (Sterna hirundo), and least tern (S. antillarum). Monitoring of nesting activities of these species from 2002 to 2005 indicated that all species except black ducks colonized the site rapidly. More than 800 pairs of common terns nested in 2003 to 2004. Because of predation by red fox (Vulpes vulpes) and great horned owl (Bubo virginianus), reproductive success was very low for the terns. Trapping was effective in removing the foxes, and other controls have been applied to opportunistic nesting species including herring gulls (Larus argentatus) and Canada geese (Branta canadensis). An effective public education program on the island has helped address concerns about animal control.

  4. Mechanisms of water interaction with pore systems of hydrochar and pyrochar from poplar forestry waste.

    PubMed

    Conte, Pellegrino; Hanke, Ulrich M; Marsala, Valentina; Cimò, Giulia; Alonzo, Giuseppe; Glaser, Bruno

    2014-05-28

    The aim of this study was to understand the water-surface interactions of two chars obtained by gasification (pyrochar) and hydrothermal carbonization (hydrochar) of a poplar biomass. The two samples revealed different chemical compositions as evidenced by solid state (13)C NMR spectroscopy. In fact, hydrochar resulted in a lignin-like material still containing oxygenated functionalities. Pyrochar was a polyaromatic system in which no heteronuclei were detected. After saturation with water, hydrochar and pyrochar were analyzed by fast field cycling (FFC) NMR relaxometry. Results showed that water movement in hydrochar was mainly confined in very small pores. Conversely, water movement in pyrochar led to the conclusion that a larger number of transitional and very large pores were present. These results were confirmed by porosity evaluation derived from gas adsorption. Variable-temperature FFC NMR experiments confirmed a slow-motion regime due to a preferential diffusion of water on the solid surface. Conversely, the higher number of large pores in pyrochar allowed slow movement only up to 50 °C. As the temperature was raised to 80 °C, water interactions with the pore surface became weaker, thereby allowing a three-dimensional water exchange with the bulk liquid. This paper has shown that pore size distribution was more important than chemical composition in affecting water movement in two chemically different charred systems.

  5. Structural Transformation of Isolated Poplar and Switchgrass Lignins from Dilute Acid Pretreatment

    DOE PAGES

    Sun, Qining; Pu, Yunqiao; Meng, Xianzhi; ...

    2015-08-27

    A key step in conversion of cellulosic biomass into sustainable fuels and chemicals is thermochemical pretreatment to reduce plant cell wall recalcitrance. Obtaining an improved understanding of the fundamental chemistry of lignin, the most recalcitrant component of biomass, during pretreatment is critical to the continued development of renewable biofuel production. To examine the intrinsic chemistry of lignin during dilute acid pretreatment (DAP), lignin was isolated from poplar and switchgrass using a cellulolytic enzyme system and then treated under DAP conditions. These results highlight that lignin is subjected to depolymerization reactions within the first 2 min of dilute acid pretreatment andmore » these changes are accompanied by increased generation of aliphatic and phenolic hydroxyl groups of lignin. This is followed by a competing set of depolymerization and repolymerization reactions that lead to a decrease in the content of guaiacyl lignin units and an increase in condensed lignin units as the reaction residence time is extended beyond 5 min. Finally, we showed that a detailed comparison of changes in functional groups and molecular weights of cellulolytic enzyme lignins with different structural parameters, related to the recalcitrant properties of lignin, could be successfully altered during DAP conditions.« less

  6. An inventory of wetlands in the East Fork Poplar Creek floodplain, Anderson and Roane Counties, Tennessee

    SciTech Connect

    1992-12-01

    An inventory of wetlands within the floodplain of East Fork Poplar Creek (EFPC) in Anderson and Roane Counties, Tennessee was conducted during October, 1991 through May, 1992 for the US Department of Energy (DOE) by the US Army Corps of Engineers, Nashville District. About 15 miles of EFPC channel and 500 acres of its floodplain are contaminated with mercury and other contaminants released from the Y-12 Plant on the DOE Oak Ridge Reservation. The wetland inventory will serve as baseline information for DOE`s remedial action planning and National Environmental Policy Act compliance efforts related to the contamination. In order to provide broad wetland determinations beyond which future wetland definitions are unlikely to expand, the 1989 Federal Manual for Identifying And Delineating Jurisdictional Wetlands was utilized. Using the manual`s methodology in a contaminated system under the approved health and safety plan presented some unique problems, resulting in intrusive sampling for field indicators of hydric soils being accomplished separately from observation of other criteria. Beginning with wetland areas identified on National Wetland Inventory Maps, the entire floodplain was examined for presence of wetland criteria, and 17 wetlands were identified ranging from 0.01 to 2.81 acres in size. The majority of wetlands identified were sized under 1 acre. Some of the wetlands identified were not delineated on the National Wetland Inventory Maps, and much of the wetland area delineated on the maps did not meet the criteria under the 1989 manual.

  7. Quarterly Progress Report on the Biological Monitoring Program for East Fork Poplar Creek

    SciTech Connect

    Adams, S.M.; Ashwood, T.L.; Cicerone, D.S.; Greeley, M.S. Jr.; Hill, W.R.; Kszos, L.A.

    1996-12-30

    In May 1985, a National Pollutant Discharge Elimination System (NPDES) permit was issued for the Oak Ridge Y-12 Plant. As a condition of the permit, a Biological Monitoring and Abatement Program ( BMAP) was developed to demonstrate that the effluent limitations established for the Y-12 Plant protect the classified uses of the receiving stream (East Fork Poplar Creek; EFPC), in particular, the growth and propagation of aquatic life (Lear et al. 1989). A second objective of the BMAP is to document the ecological effects resulting from the implementation of a water pollution control program designed to eliminate direct discharges of wastewaters to EFPC and to minimize the inadvertent release of pollutants to the environment. Because of the complex nature of the discharges to EFPC and the temporal and spatial variability in the composition of the discharges, a comprehensive, integrated approach to biological monitoring was developed. A new permit was issued to the Y-12 Plant on April 28, 1995 and became effective on July 1, 1995. Biological monitoring continues to be required under the new permit. The BMAP consists of four major tasks that reflect different but complementary approaches to evaluating the effects of the Y-12 Plant discharges on the aquatic integrity of EFPC. These tasks are (1) toxicity monitoring, (2) biological indicator studies, (3) bioaccumulation studies, and (4) ecological surveys of the periphyton, benthic macroinvertebrate, and fish communities.

  8. Physicochemical structural changes of poplar and switchgrass during biomass pretreatment and enzymatic hydrolysis

    SciTech Connect

    Meng, Xianzhi; Sun, Qining; Kosa, Matyas; Huang, Fang; Pu, Yunqiao; Ragauskas, Arthur J.

    2016-07-27

    Converting lignocellulosics to simple sugars for second generation bioethanol is complicated due to biomass recalcitrance, and it requires a pretreatment stage prior to enzymatic hydrolysis. In this study, native, pretreated (acid and alkaline) and partially hydrolyzed poplar and switchgrass were characterized by using Simons’ staining for cellulose accessibility, GPC for degree of polymerization (DP), and FTIR for chemical structure of plant cell wall. The susceptibility of the pretreated biomass to enzymatic hydrolysis could not be easily predicted from differences in cellulose DP and accessibility. During hydrolysis, the most significant DP reduction occurred at the very beginning of hydrolysis, and the DP began to decrease at a significantly slower rate after this initial period, suggesting an existence of a synergistic action of endo- and exoglucanases that contribute to the occurrence of a “peeling off” mechanism. Cellulose accessibility was found to be increased at the beginning of hydrolysis, after reaching a maximum value then started to decrease. In conclusion, the fresh enzyme restart hydrolysis experiment along with the accessibility data indicated that the factors associated with the nature of enzyme such as irreversible nonspecific binding of cellulases by lignin and steric hindrance of enzymes should be responsible for the gradual slowing down of the reaction rate.

  9. Bioethanol production from deacetylated yellow poplar pretreated with oxalic acid recovered through electrodialysis.

    PubMed

    Kundu, Chandan; Jeong, So-Yeon; Lee, Jae-Won

    2016-05-01

    Electrodialysis (ED) was used to develop a multistage oxalic acid recovery and pretreatment system to produce ethanol from deacetylated yellow poplar. Pretreatment of the biomass was performed at 150°C for 42 min using 0.16 M oxalic acid. The efficiency of oxalic acid recovery from the hydrolysate reached up to 92.32% in all the stages. Ethanol production and ethanol yield of ED-treated hydrolysate in each stage showed a uniform pattern ranging from 6.81 g/L to 7.21 g/L and 0.40 g/g to 0.43 g/g, respectively. The results showed that efficiency of ethanol production increased when deacetylated biomass and ED process was used. Ethanol yield from the pretreated biomass using simultaneous saccharification and fermentation (SSF) was in the range of 80.59-83.36% in all the stages. The structural characterization of the pretreated biomass at each stage was investigated and structural changes were not significantly different among the various pretreated biomass.

  10. Morphological and Molecular Characterization of Two Aphelenchoides Endophytic in Poplar Leaves.

    PubMed

    Carta, Lynn K; Li, Shiguang; Skantar, Andrea M; Newcombe, George

    2016-03-01

    During a long-term, large network study of the ecology of plant endophytes in native habitats, various nematodes have been found. Two poplar species, Populus angustifolia (narrowleaf cottonwood) and Populus trichocarpa (black cottonwood), are important ecological and genomic models now used in ongoing plant-pathogen-endophyte interaction studies. In this study, two different aphelenchid nematodes within surface-sterilized healthy leaves of these two Populus spp. in northwestern North America were discovered. Nematodes were identified and characterized microscopically and molecularly with 28S ribosomal RNA (rRNA) and 18S rRNA molecular markers. From P. angustifolia, Aphelenchoides saprophilus was inferred to be closest to another population of A. saprophilus among sequenced taxa in the 18S tree. From P. trichocarpa, Laimaphelenchus heidelbergi had a 28S sequence only 1 bp different from that of a Portuguese population, and 1 bp different from the original Australian type population. The 28S and 18S rRNA trees of Aphelenchoides and Laimaphelenchus species indicated L. heidelbergi failed to cluster with three other Laimaphelenchus species, including the type species of the genus. Therefore, we support a conservative definition of the genus Laimaphelenchus, and consider these populations to belong to Aphelenchoides, amended as Aphelenchoides heidelbergi n. comb. This is the first report of these nematode species from within aboveground leaves. The presence of these fungal-feeding nematodes can affect the balance of endophytic fungi, which are important determinants of plant health.

  11. Patterns of Auxin Distribution during Gravitational Induction of Reaction Wood in Poplar and Pine1

    PubMed Central

    Hellgren, Jenny M.; Olofsson, Kjell; Sundberg, Björn

    2004-01-01

    Gravistimulation of tree stems affects wood development by unilaterally inducing wood with modified properties, called reaction wood. Commonly, it also stimulates cambial growth on the reaction wood side. Numerous experiments involving applications of indole-3-acetic acid (IAA) or IAA-transport inhibitors have suggested that reaction wood is induced by a redistribution of IAA around the stem. However, in planta proof for this model is lacking. Therefore, we have mapped endogenous IAA distribution across the cambial region tissues in both aspen (Populus tremula, denoted poplar) and Scots pine (Pinus sylvestris) trees forming reaction wood, using tangential cryosectioning combined with sensitive gas chromatography-mass spectrometry analysis. Moreover, we have documented the kinetics of IAA during reaction wood induction in these species. Our analysis of endogenous IAA demonstrates that reaction wood is formed without any obvious alterations in IAA balance. This is in contrast to gravitropic responses in roots and shoots where a redistribution of IAA has been documented. It is also of interest that cambial growth on the tension wood side was stimulated without an increase in IAA. Taken together, our results suggest a role for signals other than IAA in the reaction wood response, or that the gravitational stimulus interacts with the IAA signal transduction pathway. PMID:15122024

  12. Mini-review of knowledge gaps in salt tolerance of plants applied to willows and poplars.

    PubMed

    Mirck, Jaconette; Zalesny, Ronald S

    2015-01-01

    Salt tolerance of agricultural crops has been studied since the 1940, but knowledge regarding salt tolerance of woody crops is still in its initial phase. Salt tolerance of agricultural crops has been expressed as the yield decrease due to a certain salt concentration within the root zone as compared to a non-saline control. The most well-known plant response curve to salinity has been a piece-wise linear regression relating crop yield to root zone salinity. This method used the hypothesis that crops tolerate salt up to a threshold after which their yield decreases approximately linearly. Critique to this method included its lack of sensitivity to dynamic factors such as weather conditions. As a result, other classification indices have been developed, but none is as well accepted as the threshold-slope model. In addition to a mini-review of the key salt tolerance studies, our objective was to classify salt tolerance levels of poplars and willows. Initial classification showed that salt tolerance of these genera ranged from sensitive to moderately tolerant.

  13. Two highly validated SSR multiplexes (8-plex) for Euphrates' poplar, Populus euphratica (Salicaceae).

    PubMed

    Xu, Fang; Feng, Sisi; Wu, Rongling; Du, Fang K

    2013-01-01

    Multiplex PCR amplification of microsatellites has significantly increased the throughput and decreased the costs of genotyping. We have developed two highly polymorphic microsatellite multiplexes for Populus euphratica, the only tree species found in desert regions of Western China and adjacent Central Asian countries. The first of these multiplex kits comprises an eight-Plex of genomic SSRs (gSSRs) obtained from published databases. The second comprises an eight-plex of newly designed EST-SSRs (eSSRs) based on expressed sequence tags for P. euphratica. Both kits were tested on a sample of 170 individuals from four populations. The gSSRs exhibited slightly more polymorphism than the eSSRs. The new multiplex protocols yielded consistent results in the hands of multiple researchers, demonstrating their robustness. The 16 loci used in the kits exhibited a high transferability rate (82.0%) in eight other poplar species belonging to five different sections of the genus. Both kits should therefore be useful for further investigations of population genetics in P. euphratica and related species. Our results indicate that it is essential to follow recently established recommendations when developing microsatellite markers, including verifying the amplification efficiency, detecting null alleles and carefully measuring error rates.

  14. Genomic diversity, population structure, and migration following rapid range expansion in the Balsam poplar, Populus balsamifera.

    PubMed

    Keller, Stephen R; Olson, Matthew S; Silim, Salim; Schroeder, William; Tiffin, Peter

    2010-03-01

    Rapid range expansions can cause pervasive changes in the genetic diversity and structure of populations. The postglacial history of the Balsam Poplar, Populus balsamifera, involved the colonization of most of northern North America, an area largely covered by continental ice sheets during the last glacial maximum. To characterize how this expansion shaped genomic diversity within and among populations, we developed 412 SNP markers that we assayed for a range-wide sample of 474 individuals sampled from 34 populations. We complemented the SNP data set with DNA sequence data from 11 nuclear loci from 94 individuals, and used coalescent analyses to estimate historical population size, demographic growth, and patterns of migration. Bayesian clustering identified three geographically separated demes found in the Northern, Central, and Eastern portions of the species' range. These demes varied significantly in nucleotide diversity, the abundance of private polymorphisms, and population substructure. Most measures supported the Central deme as descended from the primary refuge of diversity. Both SNPs and sequence data suggested recent population growth, and coalescent analyses of historical migration suggested a massive expansion from the Centre to the North and East. Collectively, these data demonstrate the strong influence that range expansions exert on genomic diversity, both within local populations and across the range. Our results suggest that an in-depth knowledge of nucleotide diversity following expansion requires sampling within multiple populations, and highlight the utility of combining insights from different data types in population genomic studies.

  15. Mercury contamination in the riparian zones along the East Fork Poplar Creek at Oak Ridge.

    PubMed

    Pant, P; Allen, M; Tansel, B

    2011-03-01

    Oak Ridge (Tennessee, USA) has a history of mercury (Hg) contamination in its aquatic and soil environment associated with past nuclear-weapons production activities at its Department of Energy (DOE) sites. Three different riparian zones along the Lower East Fork Poplar Creek were investigated in order to study Hg distribution and transformation in surface soils. The surface soil samples collected from these areas showed higher total Hg on an average (129.08 mg/kg) and higher total organic carbon (5.50%) in the upstream soils compared to the other two downstream locations that contained only 31.78 and 19.98 mg/kg total Hg and 2.88% and 1.65% of TOC on average, respectively. Further, methyl Hg concentrations were also comparatively higher in case of the upstream soils (30.10 μg/kg) than that of the downstream sites (5.69 and 4.05 μg/kg). The study showed a plume-like dispersion of Hg in the terrestrial environment along the creek, with decreasing Hg concentrations with distance from the Hg source zone. Also, the transformation of Hg in the soils was found to have been influenced by the soil TOC contents.

  16. Physicochemical structural changes of poplar and switchgrass during biomass pretreatment and enzymatic hydrolysis

    DOE PAGES

    Meng, Xianzhi; Sun, Qining; Kosa, Matyas; ...

    2016-07-27

    Converting lignocellulosics to simple sugars for second generation bioethanol is complicated due to biomass recalcitrance, and it requires a pretreatment stage prior to enzymatic hydrolysis. In this study, native, pretreated (acid and alkaline) and partially hydrolyzed poplar and switchgrass were characterized by using Simons’ staining for cellulose accessibility, GPC for degree of polymerization (DP), and FTIR for chemical structure of plant cell wall. The susceptibility of the pretreated biomass to enzymatic hydrolysis could not be easily predicted from differences in cellulose DP and accessibility. During hydrolysis, the most significant DP reduction occurred at the very beginning of hydrolysis, and themore » DP began to decrease at a significantly slower rate after this initial period, suggesting an existence of a synergistic action of endo- and exoglucanases that contribute to the occurrence of a “peeling off” mechanism. Cellulose accessibility was found to be increased at the beginning of hydrolysis, after reaching a maximum value then started to decrease. In conclusion, the fresh enzyme restart hydrolysis experiment along with the accessibility data indicated that the factors associated with the nature of enzyme such as irreversible nonspecific binding of cellulases by lignin and steric hindrance of enzymes should be responsible for the gradual slowing down of the reaction rate.« less

  17. Relocation, high-latitude warming and host genetic identity shape the foliar fungal microbiome of poplars.

    PubMed

    Bálint, Miklós; Bartha, László; O'Hara, Robert B; Olson, Matthew S; Otte, Jürgen; Pfenninger, Markus; Robertson, Amanda L; Tiffin, Peter; Schmitt, Imke

    2015-01-01

    Micro-organisms associated with plants and animals affect host fitness, shape community structure and influence ecosystem properties. Climate change is expected to influence microbial communities, but their reactions are not well understood. Host-associated micro-organisms are influenced by the climate reactions of their hosts, which may undergo range shifts due to climatic niche tracking, or may be actively relocated to mitigate the effects of climate change. We used a common-garden experiment and rDNA metabarcoding to examine the effect of host relocation and high-latitude warming on the complex fungal endophytic microbiome associated with leaves of an ecologically dominant boreal forest tree (Populus balsamifera L.). We also considered the potential effects of poplar genetic identity in defining the reactions of the microbiome to the treatments. The relocation of hosts to the north increased the diversity of the microbiome and influenced its structure, with results indicating enemy release from plausible pathogens. High-latitude warming decreased microbiome diversity in comparison with natural northern conditions. The warming also caused structural changes, which made the fungal communities distinct in comparison with both low-latitude and high-latitude natural communities, and increased the abundance of plausible pathogens. The reactions of the microbiome to relocation and warming were strongly dependent on host genetic identity. This suggests that climate change effects on host-microbiome systems may be mediated by the interaction of environmental factors and the population genetic processes of the hosts.

  18. Waste Management Plan for the Lower East Fork Poplar Creek Remedial Action Project Oak Ridge, Tennessee

    SciTech Connect

    1996-08-01

    The Lower East Fork Poplar Creek (LEFPC) Remedial Action project will remove mercury-contaminated soils from the floodplain of LEFPC, dispose of these soils at the Y-12 Landfill V, and restore the affected floodplain upon completion of remediation activities. This effort will be conducted in accordance with the Record of Decision (ROD) for LEFPC as a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) action. The Waste Management Plan addresses management and disposition of all wastes generated during the remedial action for the LEFPC Project Most of the solid wastes will be considered to be sanitary or construction/demolition wastes and will be disposed of at existing Y-12 facilities for those types of waste. Some small amounts of hazardous waste are anticipated, and the possibility of low- level or mixed waste exists (greater than 35 pCi/g), although these are not expected. Liquid wastes will be generated which will be sanitary in nature and which will be capable of being disposed 0214 of at the Oak Ridge Sewage Treatment Plant.

  19. Morphological and Molecular Characterization of Two Aphelenchoides Endophytic in Poplar Leaves

    PubMed Central

    Carta, Lynn K.; Li, Shiguang; Skantar, Andrea M.; Newcombe, George

    2016-01-01

    During a long-term, large network study of the ecology of plant endophytes in native habitats, various nematodes have been found. Two poplar species, Populus angustifolia (narrowleaf cottonwood) and Populus trichocarpa (black cottonwood), are important ecological and genomic models now used in ongoing plant–pathogen–endophyte interaction studies. In this study, two different aphelenchid nematodes within surface-sterilized healthy leaves of these two Populus spp. in northwestern North America were discovered. Nematodes were identified and characterized microscopically and molecularly with 28S ribosomal RNA (rRNA) and 18S rRNA molecular markers. From P. angustifolia, Aphelenchoides saprophilus was inferred to be closest to another population of A. saprophilus among sequenced taxa in the 18S tree. From P. trichocarpa, Laimaphelenchus heidelbergi had a 28S sequence only 1 bp different from that of a Portuguese population, and 1 bp different from the original Australian type population. The 28S and 18S rRNA trees of Aphelenchoides and Laimaphelenchus species indicated L. heidelbergi failed to cluster with three other Laimaphelenchus species, including the type species of the genus. Therefore, we support a conservative definition of the genus Laimaphelenchus, and consider these populations to belong to Aphelenchoides, amended as Aphelenchoides heidelbergi n. comb. This is the first report of these nematode species from within aboveground leaves. The presence of these fungal-feeding nematodes can affect the balance of endophytic fungi, which are important determinants of plant health. PMID:27168650

  20. A National Assessment of Promising Areas for Switchgrass, Hybrid Poplar, or Willow Energy Crop Production

    SciTech Connect

    Graham, R.L.; Walsh, M.E.

    1999-02-01

    The objective of this paper is to systematically assess the cropland acreage that could support energy crops and the expected farm gate and delivered prices of energy crops. The assessment is based on output from two modeling approaches: (1) the Oak Ridge County-Level Energy Crop (ORECCL) database (1996 version) and (2) the Oak Ridge Integrated Bioenergy Analysis System (ORIBAS). The former provides county-level estimates of suitable acres, yields, and farmgate prices of energy crops (switchgrass, hybrid poplar, willow) for all fifty states. The latter estimates delivered feedstock prices and quantities within a state at a fine resolution (1 km2) and considers the interplay between transportation costs, farmgate prices, cropland density, and facility demand. It can be used to look at any type of feedstock given the appropriate input parameters. For the purposes of this assessment, ORIBAS has been used to estimate farmgate and delivered switchgrass prices in 11 states (AL, FL, GA, IA, M N, MO, ND, NE, SC, SD, and TN). Because the potential for energy crop production can be considered from several perspectives, and is evolving as policies, economics and our basic understanding of energy crop yields and production costs change, this assessment should be viewed as a snapshot in time.

  1. Synergetic Effects of Alcohol/Water Mixing on the Catalytic Reductive Fractionation of Poplar Wood

    SciTech Connect

    Renders, Tom; Van den Bosch, Sander; Vangeel, Thijs; Ennaert, Thijs; Koelewijn, Steven-Friso; Van den Bossche, Gil; Courtin, Christophe M.; Schutyser, Wouter; Sels, Bert F.

    2016-12-05

    One of the foremost challenges in lignocellulose conversion encompasses the integration of effective lignin valorization in current carbohydrate-oriented biorefinery schemes. Catalytic reductive fractionation (CRF) of lignocellulose offers a technology to simultaneously produce lignin-derived platform chemicals and a carbohydrate-enriched pulp via the combined action of lignin solvolysis and metal-catalyzed hydrogenolysis. Herein, the solvent (composition) plays a crucial role. In this contribution, we study the influence of alcohol/water mixtures by processing poplar sawdust in varying MeOH/water and EtOH/water blends. The results show particular effects that strongly depend on the applied water concentration. Low water concentrations enhance the removal of lignin from the biomass, while the majority of the carbohydrates are left untouched (scenario A). Contrarily, high water concentrations favor the solubilization of both hemicellulose and lignin, resulting in a more pure cellulosic residue (scenario B). For both scenarios, an evaluation was made to determine the most optimal solvent composition, based on two earlier introduced empirical efficiency descriptors (denoted LFDE and LFFE). According to these measures, 30 (A) and 70 vol % water (B) showed to be the optimal balance for both MeOH/water and EtOH/water mixtures. This successful implementation of alcohol/water mixtures allows operation under milder processing conditions in comparison to pure alcohol solvents, which is advantageous from an industrial point of view.

  2. Genome-wide analysis of WOX gene family in rice, sorghum, maize, Arabidopsis and poplar.

    PubMed

    Zhang, Xin; Zong, Jie; Liu, Jianhua; Yin, Jinyuan; Zhang, Dabing

    2010-11-01

    WUSCHEL-related homeobox (WOX) genes form a large gene family specifically expressed in plants. They are known to play important roles in regulating the development of plant tissues and organs by determining cell fate. Recent available whole genome sequences allow us to do more comprehensive phylogenetic analysis of the WOX genes in plants. In the present study, we identified 11 and 21 WOXs from sorghum (Sorghum bicolor) and maize (Zea mays), respectively. The 72 WOX genes from rice (Oryza sativa), sorghum, maize, Arabidopsis (Arabidopsis thaliana) and poplar (Populus trichocarpa) were grouped into three well supported clades with nine subgroups according to the amino acid sequences of their homodomains. Their phylogenetic relationship was also supported by the observation of the motifs outside the homodomain. We observed the variation of duplication events among the nine sub-groups between monocots and eudicots, for instance, more gene duplication events of WOXs within subgroup A for monocots, while, less for dicots in this subgroup. Furthermore, we observed the conserved intron/exon structural patterns of WOX genes in rice, sorghum and Arabidopsis. In addition, WUS (Wuschel)-box and EAR (the ERF-associated amphiphilic repression)-like motif were observed to be conserved among several WOX subgroups in these five plants. Comparative analysis of expression patterns of WOX genes in rice and Arabidopsis suggest that the WOX genes play conserved and various roles in plants. This work provides insights into the evolution of the WOX gene family and is useful for future research.

  3. The Effects on Lignin Structure of Overexpression of Ferulate 5-Hydroxylase in Hybrid Poplar1[W

    PubMed Central

    Stewart, Jaclyn J.; Akiyama, Takuya; Chapple, Clint; Ralph, John; Mansfield, Shawn D.

    2009-01-01

    Poplar (Populus tremula × alba) lignins with exceedingly high syringyl monomer levels are produced by overexpression of the ferulate 5-hydroxylase (F5H) gene driven by a cinnamate 4-hydroxylase (C4H) promoter. Compositional data derived from both standard degradative methods and NMR analyses of the entire lignin component (as well as isolated lignin fraction) indicated that the C4H∷F5H transgenic's lignin was comprised of as much as 97.5% syringyl units (derived from sinapyl alcohol), the remainder being guaiacyl units (derived from coniferyl alcohol); the syringyl level in the wild-type control was 68%. The resultant transgenic lignins are more linear and display a lower degree of polymerization. Although the crucial β-ether content is similar, the distribution of other interunit linkages in the lignin polymer is markedly different, with higher resinol (β-β) and spirodienone (β-1) contents, but with virtually no phenylcoumarans (β-5, which can only be formed from guaiacyl units). p-Hydroxybenzoates, acylating the γ-positions of lignin side chains, were reduced by >50%, suggesting consequent impacts on related pathways. A model depicting the putative structure of the transgenic lignin resulting from the overexpression of F5H is presented. The altered structural features in the transgenic lignin polymer, as revealed here, support the contention that there are significant opportunities to improve biomass utilization by exploiting the malleability of plant lignification processes. PMID:19386808

  4. Developing xylem-preferential expression of PdGA20ox1, a gibberellin 20-oxidase 1 from Pinus densiflora, improves woody biomass production in a hybrid poplar.

    PubMed

    Jeon, Hyung-Woo; Cho, Jin-Seong; Park, Eung-Jun; Han, Kyung-Hwan; Choi, Young-Im; Ko, Jae-Heung

    2016-04-01

    Woody biomass has gained popularity as an environmentally friendly, renewable and sustainable resource for liquid fuel production. Here, we demonstrate biotechnological improvement of the quantity and quality of woody biomass by employing developing xylem (DX)-preferential production of gibberellin (GA), a phytohormone that positively regulates stem growth. First, for the proof of concept experiment, we produced transgenic Arabidopsis plants expressing GA20-oxidase, a key enzyme in the production of bioactive GAs, from Pinus densiflora (PdGA20ox1) under the control of either a constitutive 35S promoter, designated 35S::PdGA20ox1, or a DX-specific promoter (originated from poplar), designated DX15::PdGA20ox1. As we hypothesized, both transgenic Arabidopsis plants (35S::PdGA20ox1 and DX15::PdGA20ox1) exhibited an accelerated stem growth that resulted in a large increase of biomass, up to 300% compared to wild-type control plants, together with increased secondary wall thickening and elongation of fibre cells. Next, we applied our concept to the production of transgenic poplar trees. Both transgenic poplar trees (35S::PdGA20ox1 and DX15::PdGA20ox1) showed dramatic increases in biomass, up to 300%, with accelerated stem growth and xylem differentiation. Cell wall monosaccharide composition analysis revealed that in both Arabidopsis and poplar, glucose and xylose contents were significantly increased. However, undesirable phenotypes of 35S::PdGA20ox1 poplar, including poor root growth and leaf development, were found. Interestingly, DX15::PdGA20ox1 poplar resulted in a reduction of undesirable phenotypes. Our results indicate that the controlled production of GAs through a tissue-specific promoter can be utilized as an efficient biotechnological tool for producing enhanced plant biomass, minimizing unwanted effects.

  5. Phenolic composition and antioxidant properties of poplar bud (Populus nigra) extract: individual antioxidant contribution of phenolics and transcriptional effect on skin aging.

    PubMed

    Dudonné, Stéphanie; Poupard, Pascal; Coutière, Philippe; Woillez, Marion; Richard, Tristan; Mérillon, Jean-Michel; Vitrac, Xavier

    2011-05-11

    The Populus species possess great potential for therapeutical applications, especially for their known anti-inflammatory properties. The antioxidant properties of propolis, a hive product collected by honey bees mainly from poplar bud exudates, suggest that poplar buds also possess antioxidant properties. Here is reported the characterization of the antioxidant properties of an aqueous poplar bud (Populus nigra) extract. It presented a high total phenolic content, and moderate antioxidant properties as determined by ORAC assay. The main phenolic compounds identified were phenolic acids and flavonoid aglycons. These phenolic compounds were analyzed by ORAC assay for their individual antioxidant activity, in order to determine the major contributors to the total antioxidant activity of the extract. Thanks to their high antioxidant activity, caffeic and p-coumaric acids were identified as the major antioxidant components. Representing only 3.5% of its dry weight, these compounds represented together about 50% of the total antioxidant activity of the extract. The antioxidant properties of poplar bud extract and the phenolic compounds identified were also analyzed by cellular antioxidant activity assay (CAA), which was weakly correlated with ORAC assay. The transcriptional effect of poplar bud extract on skin aging was evaluated in vitro on a replicative senescence model of normal human dermal fibroblasts, using a customized DNA macroarray specifically designed to investigate skin aging markers. Among the detected genes, poplar bud extract significantly regulated genes involved in antioxidant defenses, inflammatory response and cell renewal. The collective antioxidant properties and transcriptional effect of this extract suggest potential antiaging properties which could be utilized in cosmetic and nutraceutical formulations.

  6. A Comprehensive Analysis of the Transcriptomes of Marssonina brunnea and Infected Poplar Leaves to Capture Vital Events in Host-Pathogen Interactions

    PubMed Central

    Zhang, Liang; Xu, Minjie; Jiang, Jianping; Dou, Tonghai; Lin, Wei; Zhao, Guoping; Huang, Minren; Zhou, Yan

    2015-01-01

    Background Understanding host-pathogen interaction mechanisms helps to elucidate the entire infection process and focus on important events, and it is a promising approach for improvement of disease control and selection of treatment strategy. Time-course host-pathogen transcriptome analyses and network inference have been applied to unravel the direct or indirect relationships of gene expression alterations. However, time series analyses can suffer from absent time points due to technical problems such as RNA degradation, which limits the application of algorithms that require strict sequential sampling. Here, we introduce an efficient method using independence test to infer an independent network that is exclusively concerned with the frequency of gene expression changes. Results Highly resistant NL895 poplar leaves and weakly resistant NL214 leaves were infected with highly active and weakly active Marssonina brunnea, respectively, and were harvested at different time points. The independent network inference illustrated the top 1,000 vital fungus-poplar relationships, which contained 768 fungal genes and 54 poplar genes. These genes could be classified into three categories: a fungal gene surrounded by many poplar genes; a poplar gene connected to many fungal genes; and other genes (possessing low degrees of connectivity). Notably, the fungal gene M6_08342 (a metalloprotease) was connected to 10 poplar genes, particularly including two disease-resistance genes. These core genes, which are surrounded by other genes, may be of particular importance in complicated infection processes and worthy of further investigation. Conclusions We provide a clear framework of the interaction network and identify a number of candidate key effectors in this process, which might assist in functional tests, resistant clone selection, and disease control in the future. PMID:26222429

  7. Evolution of a domain conserved in microtubule-associated proteins of eukaryotes

    PubMed Central

    Rajangam, Alex S; Yang, Hongqian; Teeri, Tuula T; Arvestad, Lars

    2008-01-01

    The microtubule network, the major organelle of the eukaryotic cytoskeleton, is involved in cell division and differentiation but also with many other cellular functions. In plants, microtubules seem to be involved in the ordered deposition of cellulose microfibrils by a so far unknown mechanism. Microtubule-associated proteins (MAP) typically contain various domains targeting or binding proteins with different functions to microtubules. Here we have investigated a proposed microtubule-targeting domain, TPX2, first identified in the Kinesin-like protein 2 in Xenopus. A TPX2 containing microtubule binding protein, PttMAP20, has been recently identified in poplar tissues undergoing xylogenesis. Furthermore, the herbicide 2,6-dichlorobenzonitrile (DCB), which is a known inhibitor of cellulose synthesis, was shown to bind specifically to PttMAP20. It is thus possible that PttMAP20 may have a role in coupling cellulose biosynthesis and the microtubular networks in poplar secondary cell walls. In order to get more insight into the occurrence, evolution and potential functions of TPX2-containing proteins we have carried out bioinformatic analysis for all genes so far found to encode TPX2 domains with special reference to poplar PttMAP20 and its putative orthologs in other plants. PMID:21918606

  8. Spatial variability of soil carbon and nitrogen in two hybrid poplar-hay crop systems in southern Quebec, Canada

    NASA Astrophysics Data System (ADS)

    Winans, K. S.

    2013-12-01

    Canadian agricultural operations contribute approximately 8% of national GHG emissions each year, mainly from fertilizers, enteric fermentation, and manure management (Environment Canada, 2010). With improved management of cropland and forests, it is possible to mitigate GHG emissions through carbon (C) sequestration while enhancing soil and crop productivity. Tree-based intercropped (TBI) systems, consisting of a fast-growing woody species such as poplar (Populus spp.) planted in widely-spaced rows with crops cultivated between tree rows, were one of the technologies prioritized for investigation by the Agreement for the Agricultural Greenhouse Gases Program (AAGGP), because fast growing trees can be a sink for atmospheric carbon-dioxide (CO2) as well as a long-term source of farm income (Montagnini and Nair, 2004). However, there are relatively few estimates of the C sequestration in the trees or due to tree inputs (e.g., fine root turnover, litterfall that gets incorporated into SOC), and hybrid poplars grow exponentially in the first 8-10 years after planting. With the current study, our objectives were (1) to evaluate spatial variation in soil C and nitrogen (N) storage, CO2 and nitrogen oxide (N20), and tree and crop productivity for two hybrid poplar-hay intercrop systems at year 9, comparing TBI vs. non-TBI systems, and (2) to evaluate TBI systems in the current context of C trading markets, which value C sequestration in trees, unharvested crop components, and soils of TBI systems. The study results will provide meaningful measures that indicate changes due to TBI systems in the short-term and in the long-term, in terms of GHG mitigation, enhanced soil and crop productivity, as well as the expected economic returns in TBI systems.

  9. Remedial investigation/feasibility study for the Clinch River/Poplar Creek operable unit. Volume 4. Appendix F

    SciTech Connect

    1995-09-01

    This section contains ecotoxicological profiles for the COPECs for the combined Remedial Investigation/Feasibility Study Report for the Clinch River/Poplar Crack (CR/PC) Operable Unit (OU). The ecotoxicological information is presented for only those endpoints for which the chemicals are COPECs. The CR/PC OU is located in Anderson and Roane Counties, Tennessee and consists of the Clinch River and several of its embayments in Melton Hill and Watts Bar Reservoirs. These waters have received hazardous substances released over a period of 50 years from the US Department of Energy`s Oak Ridge Reservation (ORR), a National Priority List site established under the Comprehensive Environmental Response, Compensation, and Liability Act. A remedial investigation has been conducted to determine the current nature and extent of any contamination and to assess the resulting risk to human health and the environment. The feasibility study evaluates remedial action alternatives to identify any that are feasible for implementation and that would effectively reduce risk. Historical studies had indicated that current problems would likely include {sup 137}Cs in sediment of the Clinch River, mercury in sediment and fish of Poplar Creek and PCBs and pesticides in fish from throughout the OU. Peak releases of mercury and {sup 137}Cs occurred over 35 years ago, and current releases are low. Past releases of PCBs from the ORR are poorly quantified, and current releases are difficult to quantify because levels are so low. The site characterization focused on contaminants in surface water, sediment, and biota. Contaminants in surface water were all found to be below Ambient Water Quality Criteria. Other findings included the following: elevated metals including cesium 137 and mercury in McCoy Branch sediments; PCBs and chlordane elevated in several fish species, presenting the only major human health risk, significant ecological risks in Poplar Creek but not in the Clinch River.

  10. Remedial investigation/feasibility study for the Clinch River/Poplar Creek operable unit. Volume 1. Main text

    SciTech Connect

    1995-09-01

    This is the combined Remedial Investigation/Feasibility Study Report for the Clinch River/Poplar Crack (CR/PC) Operable Unit (OU). The CR/PC OU is located in Anderson and Roane Counties, Tennessee and consists of the Clinch River and several of its embayments in Melton Hill and Watts Bar Reservoirs. These waters have received hazardous substances released over a period of 50 years from the US Department of Energy`s Oak Ridge Reservation (ORR), a National Priority List site established under the Comprehensive Environmental Response, Compensation, and Liability Act. A remedial investigation has been conducted to determine the current nature and extent of any contamination and to assess the resulting risk to human health and the environment. The feasibility study evaluates remedial action alternatives to identify any that are feasible for implementation and that would effectively reduce risk. Historical studies had indicated that current problems would likely include {sup 137}Cs in sediment of the Clinch River, mercury in sediment and fish of Poplar Creek and PCBs and pesticides in fish from throughout the OU. Peak releases of mercury and {sup 137}Cs occurred over 35 years ago, and current releases are low. Past releases of PCBs from the ORR are poorly quantified, and current releases are difficult to quantify because levels are so low. The site characterization focused on contaminants in surface water, sediment, and biota. Contaminants in surface water were all found to be below Ambient Water Quality Criteria. Other findings included the following: elevated metals including cesium 137 and mercury in McCoy Branch sediments; PCBs and chlordane elevated in several fish species, presenting the only major human health risk, significant ecological risks in Poplar Creek but not in the Clinch River.

  11. Remedial investigation/feasibility study for the Clinch River/Poplar Creek operable unit. Volume 3. Appendix E

    SciTech Connect

    1995-09-01

    This document contains Appendix E: Toxicity Information and Uncertainty Analysis, description of methods, from the combined Remedial Investigation/Feasibility Study Report for the Clinch River/Poplar Crack (CR/PC) Operable Unit (OU). The CR/PC OU is located in Anderson and Roane Counties, Tennessee and consists of the Clinch River and several of its embayments in Melton Hill and Watts Bar Reservoirs. These waters have received hazardous substances released over a period of 50 years from the US Department of Energy`s Oak Ridge Reservation (ORR), a National Priority List site established under the Comprehensive Environmental Response, Compensation, and Liability Act. A remedial investigation has been conducted to determine the current nature and extent of any contamination and to assess the resulting risk to human health and the environment. The feasibility study evaluates remedial action alternatives to identify any that are feasible for implementation and that would effectively reduce risk. Historical studies had indicated that current problems would likely include {sup 137}Cs in sediment of the Clinch River, mercury in sediment and fish of Poplar Creek and PCBs and pesticides in fish from throughout the OU. Peak releases of mercury and {sup 137}Cs occurred over 35 years ago, and current releases are low. Past releases of PCBs from the ORR are poorly quantified, and current releases are difficult to quantify because levels are so low. The site characterization focused on contaminants in surface water, sediment, and biota. Contaminants in surface water were all found to be below Ambient Water Quality Criteria. Other findings included the following: elevated metals including cesium 137 and mercury in McCoy Branch sediments; PCBs and chlordane elevated in several fish species, presenting the only major human health risk, significant ecological risks in Poplar Creek but not in the Clinch River.

  12. Effects of isoprene production on the photosynthetic performance of Poplars (Populus sp.) under thermal and moisture stress

    NASA Astrophysics Data System (ADS)

    Parra, E. A.; McFarland, E.; Minor, R. L.; Heard, M. M.; Barron-Gafford, G.

    2015-12-01

    Poplars are an important agro-forestry product used for both biofuel and paper production. Importantly, all poplars are not created equal - some have the potential to produce isoprene, a compound thought to aid plants under temperatures and water stress conditions. Isoprene production, then, would be an important feature in a plant's response to projected climatic changes of warmer temperatures and longer inter-storm periods of drought. Our project observed how drought conditions modulated photosynthetic rates in two lineages of Populus trees, those that produce isoprene and those that have had isoprene gene knocked out. We measured leaf-level photosynthesis and thermal sensitivity from the two lineages under high and low soil water conditions in a common garden experiment. We found that both lines had similar photosynthetic rates over the range of temperatures and water exposure levels measured. However, we wondered if some of the variation we found in our data was due to the time of day of the measurements. Subsequent measurements of photosynthetic rates in the morning and afternoon on the same leaves illustrated that poplars reached higher rates of photosynthesis in the morning, but ultimately decreased faster than observed in the afternoon measurements (indicative of an eased thermal sensitivity in the afternoon). Also, we used measures of soil moisture and leaf water potential to determine that the "drought" treatment we had induced didn't actually yield any differences in the moisture status among the trees. Ultimately, our experiment showed that isoprene did not aid in photosynthesis under heat stressed conditions and that the common garden setting was not able to currently induce a water stress condition in the plants. We have begun exploring the use of low-altitude remote sensing by an unmanned aerial vehicles outfitted with thermal and multi-spectral cameras to quantify patterns of transpirational water loss, NDVI, leaf browning due to moisture stress

  13. Phase 2 confirmatory sampling data report, Lower East Fork Poplar Creek, Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    SciTech Connect

    1998-01-01

    A Remedial Investigation of East Fork Poplar Creek (EFPC) concluded that mercury is the principal contaminant of concern in the EFPC floodplain. The highest concentrations of mercury were found to be in a visually distinct black layer of soil that typically lies 15 to 30 cm (6 to 12 in.) below the surface. Mercury contamination was found to be situated in distinct areas along the floodplain, and generally at depths > 20 cm (8 in.) below the surface. In accordance with Comprehensive, Environmental Response, Compensation, and Liability Act (CERCLA), a feasibility study was prepared to assess alternatives for remediation, and a proposed plan was issued to the public in which a preferred alternative was identified. In response to public input, the plan was modified and US Department of Energy (DOE) issued a Record of Decision in 1995 committing to excavating all soil in the EFPC floodplain exceeding a concentration of 400 parts per million (ppm) of mercury. The Lower East Fork Poplar Creek (LEFPC) remedial action (RA) focuses on the stretch of EFPC flowing from Lake Reality at the Y-12 Plant, through the city of Oak Ridge, to Poplar Creek on the Oak Ridge Reservation (ORR) and its associated floodplain. Specific areas were identified that required remediation at the National Oceanographic and Atmospheric Administration (NOAA) Site along Illinois Avenue and at the Bruner Site along the Oak Ridge Turnpike. The RA was conducted in two separate phases. Phase 2, conducted from February to October 1997, completed the remediation efforts at the NOAA facility and fully remediated the Bruner Site. During both phases, data were collected to show that the remedial efforts performed at the NOAA and Bruner sites were successful in implementing the Record of Decision and had no adverse impact on the creek water quality or the city of Oak Ridge publicly owned treatment works.

  14. Reduced expression of the SHORT-ROOT gene increases the rates of growth and development in hybrid poplar and Arabidopsis.

    PubMed

    Wang, Jiehua; Andersson-Gunnerås, Sara; Gaboreanu, Ioana; Hertzberg, Magnus; Tucker, Matthew R; Zheng, Bo; Leśniewska, Joanna; Mellerowicz, Ewa J; Laux, Thomas; Sandberg, Göran; Jones, Brian

    2011-01-01

    SHORT-ROOT (SHR) is a well characterized regulator of cell division and cell fate determination in the Arabidopsis primary root. However, much less is known about the functions of SHR in the aerial parts of the plant. In this work, we cloned SHR gene from Populus trichocarpa (PtSHR1) as an AtSHR ortholog and down-regulated its expression in hybrid poplar (Populus tremula×P. tremuloides Michx-clone T89) in order to determine its physiological functions in shoot development. Sharing a 90% similarity to AtSHR at amino acid level, PtSHR1 was able to complement the Arabidopsis shr mutant. Down regulation of PtSHR1 led to a strong enhancement of primary (height) and secondary (girth) growth rates in the transgenic poplars. A similar approach in Arabidopsis showed a comparable accelerated growth and development phenotype. Our results suggest that the response to SHR could be dose-dependent and that a partial down-regulation of SHR could lead to enhanced meristem activity and a coordinated acceleration of plant growth in woody species. Therefore, SHR functions in plant growth and development as a regulator of cell division and meristem activity not only in the roots but also in the shoots. Reducing SHR expression in transgenic poplar was shown to lead to significant increases in primary and secondary growth rates. Given the current interest in bioenergy crops, SHR has a broader role as a key regulator of whole plant growth and development and SHR suppression has considerable potential for accelerating biomass accumulation in a variety of species.

  15. Secondary successional trajectories of structural and catabolic bacterial communities in oil-polluted soil planted with hybrid poplar.

    PubMed

    Mukherjee, Shinjini; Sipilä, Timo; Pulkkinen, Pertti; Yrjälä, Kim

    2015-02-01

    Poplars have widely been used for rhizoremediation of a broad range of organic contaminants for the past two decades. Still, there is a knowledge gap regarding the rhizosphere-associated bacterial communities of poplars and their dynamics during the remediation process. It is envisaged that a detailed understanding of rhizosphere-associated microbial populations will greatly contribute to a better design and implementation of rhizoremediation. To investigate the long-term succession of structural and catabolic bacterial communities in oil-polluted soil planted with hybrid poplar, we carried out a 2-year field study. Hybrid aspen (Populus tremula × Populus tremuloides) seedlings were planted in polluted soil excavated from an accidental oil-spill site. Vegetated and un-vegetated soil samples were collected for microbial community analyses at seven different time points during the course of 2 years and sampling time points were chosen to cover the seasonal variation in the boreal climate zone. Bacterial community structure was accessed by means of 16S rRNA gene amplicon pyrosequencing, whereas catabolic diversity was monitored by pyrosequencing of alkane hydroxylase and extradiol dioxygenase genes. We observed a clear succession of bacterial communities on both structural and functional levels from early to late-phase communities. Sphingomonas type extradiol dioxygenases and alkane hydroxylase homologs of Rhodococcus clearly dominated the early-phase communities. The high-dominance/low-diversity functional gene communities underwent a transition to low-dominance/high-diversity communities in the late phase. These results pointed towards increased catabolic capacities and a change from specialist to generalist strategy of bacterial communities during the course of secondary succession.

  16. Isolation and identification of phytate-degrading rhizobacteria with activity of improving growth of poplar and Masson pine.

    PubMed

    Li, Gui-E; Wu, Xiao-Qin; Ye, Jian-Ren; Hou, Liang; Zhou, Ai-Dong; Zhao, Liu

    2013-11-01

    A number of soil microorganisms can convert insoluble forms of phosphorus (P) to an accessible form to increase plant yields. Phytate is such a large kind of insoluble organic phosphorus that plants cannot absorb directly in soil, so the objectives of this study were to isolate, screen phytate-degrading rhizobacteria (PDRB), and to select potential microbial inocula that could increase the P uptake by plants. In this study, a total of 24 soil samples were collected from natural habitats of eight poplar and pine planting areas from the eastern to southern China. 17 PDRB strains were preliminarily screened from the rhizosphere soil of poplars and pines by the visible decolorization in the phytate selective medium. The highest ratio of the total diameter (colony + halo zone) to the colony diameter of the isolates was JZ-GX1, 3.85. Afterward, 17 PDRB strains were further determined for their abilities to degrade sodium phytate based on the amount of liberated inorganic P in liquid phytate specific medium. The results showed that the phytase ability of the three highest PDRB strains: JZ-GX1, JZ-DZ1 and JZ-ZJ1 were up to 2.58, 2.36 and 2.24 U/mL, respectively, much better than most of the bacteria reported in previous studies. In the soil-plant experiment, compared to CK, the best three strains of PDRB all could significantly promote growth of poplar and Masson pine under container growing. The three efficient PDRB strains were identified as follow: JZ-GX1, Rahnella aquatilis, both JZ-DZ1 and JZ-ZJ1 being autofluorescent, Pseudomonas fluorescens, by 16S rDNA gene sequencing technology, Biolog Identification System and biological characterization. The present study suggests that the three screened PDRB strains would have great potential application as biological fertilizers in the future.

  17. Reduced Expression of the SHORT-ROOT Gene Increases the Rates of Growth and Development in Hybrid Poplar and Arabidopsis

    PubMed Central

    Wang, Jiehua; Andersson-Gunnerås, Sara; Gaboreanu, Ioana; Hertzberg, Magnus; Tucker, Matthew R.; Zheng, Bo; Leśniewska, Joanna; Mellerowicz, Ewa J.; Laux, Thomas; Sandberg, Göran; Jones, Brian

    2011-01-01

    SHORT-ROOT (SHR) is a well characterized regulator of cell division and cell fate determination in the Arabidopsis primary root. However, much less is known about the functions of SHR in the aerial parts of the plant. In this work, we cloned SHR gene from Populus trichocarpa (PtSHR1) as an AtSHR ortholog and down-regulated its expression in hybrid poplar (Populus tremula×P. tremuloides Michx-clone T89) in order to determine its physiological functions in shoot development. Sharing a 90% similarity to AtSHR at amino acid level, PtSHR1 was able to complement the Arabidopsis shr mutant. Down regulation of PtSHR1 led to a strong enhancement of primary (height) and secondary (girth) growth rates in the transgenic poplars. A similar approach in Arabidopsis showed a comparable accelerated growth and development phenotype. Our results suggest that the response to SHR could be dose-dependent and that a partial down-regulation of SHR could lead to enhanced meristem activity and a coordinated acceleration of plant growth in woody species. Therefore, SHR functions in plant growth and development as a regulator of cell division and meristem activity not only in the roots but also in the shoots. Reducing SHR expression in transgenic poplar was shown to lead to significant increases in primary and secondary growth rates. Given the current interest in bioenergy crops, SHR has a broader role as a key regulator of whole plant growth and development and SHR suppression has considerable potential for accelerating biomass accumulation in a variety of species. PMID:22194939

  18. Effect of epiphytes on the extent of necrotic injuries of resistant and susceptible poplar clones infected with Dothichiza populea.

    PubMed

    Weyman-Kaczmarkowa, W; Pedziwilk, Z

    2001-01-01

    Poplar cuttings of a resistant clone, Populus 'Grandis', and susceptible clones, Populus nigra 'Italica' and Populus 'Robusta', were infected with the pathogenic fungus Dothichiza populea alone, or with the pathogen and one of five strains of epiphytes antagonistic towards it (in vitro), isolated from poplar bark. The extent of injury was examined for 28 days after infection by determining the length of necrotic patches and their area as expressed in per cent of the total area of a cutting or the area of necrotic injuries caused by the pathogen alone. All the poplar cuttings of both the resistant and susceptible clones became diseased when infected with the pathogen alone. Surprisingly enough, however, the least affected clone was the susceptible P. 'Robusta', in which necrotic injuries covered 28% of the total area, as against 40% and 70% in the resistant P. 'Grandis' and the susceptible P. nigra 'Italica', respectively. When the cuttings were infected simultaneously with Dothichiza populea and its antagonistic epiphytes, the diseased area in the resistant clone diminished by as much as two-thirds, and in the susceptible P nigra 'Italica', by one-third in comparison with the area affected by the pathogen alone. In turn, in the susceptible P. 'Robusta' the introduction of three out of five epiphytes stimulated the growth of the pathogenic fungus producing on average a double increase in the necrotic area. The differences in the response of the pathogen to the presence of epiphytes recorded in the susceptible clones indicate a marked influence of the plant on the nature of interactions between its epiphytic microflora and the pathogen.

  19. PdEPF1 regulates water-use efficiency and drought tolerance by modulating stomatal density in poplar.

    PubMed

    Wang, Congpeng; Liu, Sha; Dong, Yan; Zhao, Ying; Geng, Anke; Xia, Xinli; Yin, Weilun

    2016-03-01

    Water deficiency is a critical environmental condition that is seriously reducing global plant production. Improved water-use efficiency (WUE) and drought tolerance are effective strategies to address this problem. In this study, PdEPF1, a member of the EPIDERMAL PATTERNING FACTOR (EPF) family, was isolated from the fast-growing poplar clone NE-19 [Populus nigra × (Populus deltoides × Populus nigra)]. Significantly, higher PdEPF1 levels were detected after induction by dehydration and abscisic acid. To explore the biological functions of PdEPF1, transgenic triploid white poplars (Populus tomentosa 'YiXianCiZhu B385') overexpressing PdEPF1 were constructed. PdEPF1 overexpression resulted in increased water deficit tolerance and greater WUE. We confirmed that the transgenic lines with greater instantaneous WUE had approximately 30% lower transpiration but equivalent CO2 assimilation. Lower transpiration was associated with a 28% reduction in abaxial stomatal density. PdEPF1 overexpression not only strongly enhanced WUE, but also greatly improved drought tolerance, as measured by the leaf relative water content and water potential, under limited water conditions. In addition, the growth of these oxPdEPF1 plants was less adversely affected by reduced water availability than plants with a higher stomatal density, indicating that plants with a low stomatal density may be well suited to grow in water-scarce environments. Taken together, our data suggest that PdEPF1 improves WUE and confers drought tolerance in poplar; thus, it could be used to breed drought-tolerant plants with increased production under conditions of water deficiency.

  20. Facing the Future: Effects of Short-Term Climate Extremes on Isoprene-Emitting and Nonemitting Poplar.

    PubMed

    Vanzo, Elisa; Jud, Werner; Li, Ziru; Albert, Andreas; Domagalska, Malgorzata A; Ghirardo, Andrea; Niederbacher, Bishu; Frenzel, Juliane; Beemster, Gerrit T S; Asard, Han; Rennenberg, Heinz; Sharkey, Thomas D; Hansel, Armin; Schnitzler, Jörg-Peter

    2015-09-01

    Isoprene emissions from poplar (Populus spp.) plantations can influence atmospheric chemistry and regional climate. These emissions respond strongly to temperature, [CO2], and drought, but the superimposed effect of these three climate change factors are, for the most part, unknown. Performing predicted climate change scenario simulations (periodic and chronic heat and drought spells [HDSs] applied under elevated [CO2]), we analyzed volatile organic compound emissions, photosynthetic performance, leaf growth, and overall carbon (C) gain of poplar genotypes emitting (IE) and nonemitting (NE) isoprene. We aimed (1) to evaluate the proposed beneficial effect of isoprene emission on plant stress mitigation and recovery capacity and (2) to estimate the cumulative net C gain under the projected future climate. During HDSs, the chloroplastidic electron transport rate of NE plants became impaired, while IE plants maintained high values similar to unstressed controls. During recovery from HDS episodes, IE plants reached higher daily net CO2 assimilation rates compared with NE genotypes. Irrespective of the genotype, plants undergoing chronic HDSs showed the lowest cumulative C gain. Under control conditions simulating ambient [CO2], the C gain was lower in the IE plants than in the NE plants. In summary, the data on the overall C gain and plant growth suggest that the beneficial function of isoprene emission in poplar might be of minor importance to mitigate predicted short-term climate extremes under elevated [CO2]. Moreover, we demonstrate that an analysis of the canopy-scale dynamics of isoprene emission and photosynthetic performance under multiple stresses is essential to understand the overall performance under proposed future conditions.

  1. Facing the Future: Effects of Short-Term Climate Extremes on Isoprene-Emitting and Nonemitting Poplar1

    PubMed Central

    Vanzo, Elisa; Jud, Werner; Li, Ziru; Albert, Andreas; Domagalska, Malgorzata A.; Ghirardo, Andrea; Niederbacher, Bishu; Frenzel, Juliane; Beemster, Gerrit T.S.; Asard, Han; Rennenberg, Heinz; Sharkey, Thomas D.; Hansel, Armin; Schnitzler, Jörg-Peter

    2015-01-01

    Isoprene emissions from poplar (Populus spp.) plantations can influence atmospheric chemistry and regional climate. These emissions respond strongly to temperature, [CO2], and drought, but the superimposed effect of these three climate change factors are, for the most part, unknown. Performing predicted climate change scenario simulations (periodic and chronic heat and drought spells [HDSs] applied under elevated [CO2]), we analyzed volatile organic compound emissions, photosynthetic performance, leaf growth, and overall carbon (C) gain of poplar genotypes emitting (IE) and nonemitting (NE) isoprene. We aimed (1) to evaluate the proposed beneficial effect of isoprene emission on plant stress mitigation and recovery capacity and (2) to estimate the cumulative net C gain under the projected future climate. During HDSs, the chloroplastidic electron transport rate of NE plants became impaired, while IE plants maintained high values similar to unstressed controls. During recovery from HDS episodes, IE plants reached higher daily net CO2 assimilation rates compared with NE genotypes. Irrespective of the genotype, plants undergoing chronic HDSs showed the lowest cumulative C gain. Under control conditions simulating ambient [CO2], the C gain was lower in the IE plants than in the NE plants. In summary, the data on the overall C gain and plant growth suggest that the beneficial function of isoprene emission in poplar might be of minor importance to mitigate predicted short-term climate extremes under elevated [CO2]. Moreover, we demonstrate that an analysis of the canopy-scale dynamics of isoprene emission and photosynthetic performance under multiple stresses is essential to understand the overall performance under proposed future conditions. PMID:26162427

  2. Genetic variation of the bud and leaf phenology of seventeen poplar clones in a short rotation coppice culture.

    PubMed

    Pellis, A; Laureysens, I; Ceulemans, R

    2004-01-01

    Leaf phenology of 17 poplar ( Populus spp.) clones, encompassing spring phenology, length of growth period and end-of-year phenology, was examined over several years of different rotations. The 17 poplar clones differed in their latitude of origin (45 degrees 30'N to 51 degrees N) and were studied on a short rotation experimental field plantation, situated in Boom (province of Antwerpen, Belgium; 51 degrees 05'N, 04 degrees 22'E). A similar, clear pattern of bud burst was observed during the different years of study for all clones. Clones Columbia River, Fritzi Pauley, Trichobel (Populus trichocarpa) and Balsam Spire (Populus trichocarpa x Populus balsamifera) from 45 degrees 30'N to 49 degrees N reached bud burst (expressed as day of the year or degree day sums) almost every year earlier than clones Wolterson (Populus nigra), Gaver, Gibecq and Primo (Populus deltoides x Populus nigra) (50 degrees N to 51 degrees N). This observation could not be generalised to end-of-season phenology, for which a yearly returning pattern for all clones was lacking. Late bud burst and early leaf fall of some clones (Beaupré, Boelare, IBW1, IBW2, IBW3) was brought about by increasing rust incidence during the years of observation. For these clones, the variability in leaf phenology was reflected in high coefficients of variation among years. The patterns of genetic variation in leaf phenology have implications for short rotation intensive culture forestry and management of natural populations. Moreover, the variation in phenology reported here is relevant with regard to the genetic mapping of poplar.

  3. Sulphur limitation and early sulphur deficiency responses in poplar: significance of gene expression, metabolites, and plant hormones.

    PubMed

    Honsel, Anne; Kojima, Mikiko; Haas, Richard; Frank, Wolfgang; Sakakibara, Hitoshi; Herschbach, Cornelia; Rennenberg, Heinz

    2012-03-01

    The influence of sulphur (S) depletion on the expression of genes related to S metabolism, and on metabolite and plant hormone contents was analysed in young and mature leaves, fine roots, xylem sap, and phloem exudates of poplar (Populus tremula×Populus alba) with special focus on early consequences. S depletion was applied by a gradual decrease of sulphate availability. The observed changes were correlated with sulphate contents. Based on the decrease in sulphate contents, two phases of S depletion could be distinguished that were denominated as 'S limitation' and 'early S deficiency'. S limitation was characterized by improved sulphate uptake (enhanced root-specific sulphate transporter PtaSULTR1;2 expression) and reduction capacities (enhanced adenosine 5'-phosphosulphate (APS) reductase expression) and by enhanced remobilization of sulphate from the vacuole (enhanced putative vacuolar sulphate transporter PtaSULTR4;2 expression). During early S deficiency, whole plant distribution of S was impacted, as indicated by increasing expression of the phloem-localized sulphate transporter PtaSULTR1;1 and by decreasing glutathione contents in fine roots, young leaves, mature leaves, and phloem exudates. Furthermore, at 'early S deficiency', expression of microRNA395 (miR395), which targets transcripts of PtaATPS3/4 (ATP sulphurylase) for cleavage, increased. Changes in plant hormone contents were observed at 'early S deficiency' only. Thus, S depletion affects S and plant hormone metabolism of poplar during 'S limitation' and 'early S deficiency' in a time series of events. Despite these consequences, the impact of S depletion on growth of poplar plants appears to be less severe than in Brassicaceae such as Arabidopsis thaliana or Brassica sp.

  4. Soil nitrogen and ozone effects on growth, physiology, and nutrition of loblolly pine and yellow-poplar seedlings

    SciTech Connect

    Tjoelker, M.G.; Luxmoore, R.J.; Schwarz, O.J.

    1989-06-01

    The effects of soil nitrogen level and chronic ozone (O /sub 3/) stress on carbon and nutrient economy were investigated in loblolly pine (Pinus taeda L.) and yellow-poplar (Liriodendron tulipifera L). The objectives of the study were: (1) to compare the growth and biomass partitioning in seedlings in response to varied low-nitrogen forest soil treatments in combination with chronic ozone levels over one growing season and (2) to investigate seedling physiological responses, including water use efficiency (WUE), photosynthesis, fine root and leaf nitrate reductase activity (NRA), nutrient concentration, nutrient uptake, and nutrient use efficiency (NUE). 135 refs., 12 figs., 16 tabs.

  5. Baseline and Postremediation Monitoring Program Plan for the Lower East Fork Poplar Creek operable unit, Oak Ridge, Tennessee

    SciTech Connect

    1996-04-01

    This report was prepared in accordance with CERCLA requirements to present the plan for baseline and postremediation monitoring as part of the selected remedy. It provides the Environmental Restoration Program with information about the requirements to monitor for soil and terrestrial biota in the Lower East Fork Poplar Creek (LEFPC) floodplain; sediment, surface water, and aquatic biota in LEFPC; wetland restoration in the LEFPC floodplain; and human use of shallow groundwater wells in the LEFPC floodplain for drinking water. This document describes the monitoring program that will ensure that actions taken under Phases I and II of the LEFPC remedial action are protective of human health and the environment.

  6. Influence of brick air scrubber by-product on growth and development of corn and hybrid poplar.

    PubMed

    Thomas, Carla N; Bauerle, William L; Owino, Tom O; Chastain, John P; Klaine, Stephen J

    2007-03-01

    Studies were conducted to determine the effects of spent reagent from air pollution control scrubbers used at a brick manufacturing facility on emergence, growth, and physiological responses of corn and hybrid poplar plants. Scrubber by-product was obtained from General Shale Brick, Louisville, KY. Potting substrate was weighed and quantities of scrubber by-product were added to the substrate to obtain treatments of 0%, 6.25%, 12.5%, 25%, 50%, 75%, and 100% scrubber by-product (w:w) for the corn study. Each treatment mix was potted into nine replicate polyethylene pots and four corn seeds were sown per pot. The pots were randomized in a greenhouse at Clemson University and the number of seedlings emerging from each treatment, dark-adapted leaf chlorophyll a fluorescence, and shoot heights were measured at the end of a 21-day growth period. Then, dry shoot biomass was determined for plants from each treatment and plant tissues were analyzed for selected constituents. For the poplar study, nine-inch cuttings of hybrid poplar clone 15-29 (Populus trichocarpa x P. deltoides) and clone OP367 (P. deltoides x P. nigra) were planted in treatments of scrubber by-product-potting soil mixes of 0% , 5% , 10% , and 25% w:w. Leaf chlorophyll a fluorescence was measured over six weeks and cumulative leaf area, dry biomass, and nutrient content of tissues were determined upon harvest. Results of these studies indicate that percent seedling emergence for corn plants decreased with increasing scrubber by-product application rates. Application rates up to 12.5% scrubber by-product w:w had no adverse effect on corn seedling emergence. Shoot elongation, biomass production, and the status of the photosynthetic apparatus of the seedlings were also not severely impaired at applications below this level. A critical value of 58.2% w:w scrubber by-product was estimated to cause 25% inhibition of seedling emergence. Biomass production, cumulative leaf area, and chlorophyll a fluorescence of

  7. Evaluation of Water Use Efficiency of Short Rotation Poplar Coppice at Bohemian-Moravian Highlands

    NASA Astrophysics Data System (ADS)

    Hlaváčová, Marcela; Fischer, Milan; Mani Tripathi, Abhishek; Orság, Matěj; Trnka, Miroslav

    2015-04-01

    The water availability of the locality constitutes one of the main constraint for short rotation coppices grown on arable land. As a convenient characteristic assessing how the water use is coupled with the biomass yields, so called water use efficiency (WUE) is proposed. One method of water use efficiency determination is presented within this study. The study was carried out at short rotation poplar coppice (poplar clone J-105) at the Test Station Domanínek, Ltd. at Bohemian-Moravian Highlands during the growing season 2013. Diameters at breast height (DBH) were measured for 16 sample trees where sap flow measuring systems (Granier's Thermal Dissipation Probe, TDP) were installed. TDP outputs are expressed as temperature differences (ΔT) between the heated and non-heated probes. Estimation of sap flux density (Fd) by the Granier method relies on the measurement of temperature difference (ΔT). Determination of maximum temperature difference (ΔTmax) is fundamental for sap flux density (Fd) calculation. Although ΔTmax can be theoretically defined as ΔT at Fd = 0, many factors may prevent the occurrence of the zero flow state, such as night-time water movement for new growth (vegetative or reproductive) or water loss from the canopy due to high vapour pressure deficit (VPD). Therefore, the VPD condition was established for determination of ΔTmax. VPD condition was established as follows: VPD reaching values 0.2 at least 6 hours during night (from 21 p. m. to 3 a. m. and when the condition was fullfilled, the value at 3 a. m. was taken) because it is a supposed time after that the tree has no transpiration. The programmable part of Mini 32 software (www.emsbrno.cz) was used for application of the script establishing ΔTmax values under this VPD condition. Nevertheless, another script was applied on ΔT data set to determination of ΔTmax values for every night at 3 a. m. (as this is when ΔT should be at its daily maximum) without VPD condition restriction for

  8. Nitrogen metabolism of two contrasting poplar species during acclimation to limiting nitrogen availability.

    PubMed

    Luo, Jie; Li, Hong; Liu, Tongxian; Polle, Andrea; Peng, Changhui; Luo, Zhi-Bin

    2013-11-01

    To investigate N metabolism of two contrasting Populus species in acclimation to low N availability, saplings of slow-growing species (Populus popularis, Pp) and a fast-growing species (Populus alba × Populus glandulosa, Pg) were exposed to 10, 100, or 1000 μM NH4NO3. Despite greater root biomass and fine root surface area in Pp, lower net influxes of NH4(+) and NO3(-) at the root surface were detected in Pp compared to those in Pg, corresponding well to lower NH4(+) and NO3(-) content and total N concentration in Pp roots. Meanwhile, higher stable N isotope composition (δ(15)N) in roots and stronger responsiveness of transcriptional regulation of 18 genes involved in N metabolism were found in roots and leaves of Pp compared to those of Pg. These results indicate that the N metabolism of Pp is more sensitive to decreasing N availability than that of Pg. In both species, low N treatments decreased net influxes of NH4(+) and NO3(-), root NH4(+) and foliar NO3(-) content, root NR activities, total N concentration in roots and leaves, and transcript levels of most ammonium (AMTs) and nitrate (NRTs) transporter genes in leaves and genes involved in N assimilation in roots and leaves. Low N availability increased fine root surface area, foliar starch concentration, δ(15)N in roots and leaves, and transcript abundance of several AMTs (e.g. AMT1;2) and NRTs (e.g. NRT1;2 and NRT2;4B) in roots of both species. These data indicate that poplar species slow down processes of N acquisition and assimilation in acclimation to limiting N supply.

  9. Changes in clonal poplar leaf chemistry caused by stem galls alter herbivory and leaf litter decomposition.

    PubMed

    Künkler, Nora; Brandl, Roland; Brändle, Martin

    2013-01-01

    Gall-inducing insects are highly specialized herbivores that modify the phenotype of their host plants. Beyond the direct manipulation of plant morphology and physiology in the immediate environment of the gall, there is also evidence of plant-mediated effects of gall-inducing insects on other species of the assemblages and ecosystem processes associated with the host plant. We analysed the impact of gall infestation by the aphid Pemphigus spirothecae on chemical leaf traits of clonal Lombardy poplars (Populus nigra var. italica) and the subsequent effects on intensity of herbivory and decomposition of leaves across five sites. We measured the herbivory of two feeding guilds: leaf-chewing insects that feed on the blade (e.g. caterpillars and sawfly larvae) and skeletonising insects that feed on the mesophyll of the leaves (e.g. larvae of beetles). Galled leaves had higher phenol (35%) and lower nitrogen and cholorophyll contents (35% respectively 37%) than non-galled leaves, and these differences were stronger in August than in June. Total herbivory intensity was 27% higher on galled than on non-galled leaves; damage by leaf chewers was on average 61% higher on gall infested leaves, whereas damage by skeletonising insects was on average 39% higher on non-galled leaves. After nine months the decomposition rate of galled leaf litter was 15% lower than that of non-galled leaf litter presumably because of the lower nitrogen content of the galled leaf litter. This indicated after-life effects of gall infestation on the decomposers. We found no evidence for galling x environment interactions.

  10. Tennessee's East Fork Poplar Creek: A biological monitoring and abatement program

    SciTech Connect

    Halbrook, R.S. ); Loar, J.M.; Adams, S.M.; Black, M.C.; Boston, H.L.; Greeley, M.S. Jr.; Hill, W.R.; Hinzman, R.L.; McCarthy, J.F.; Peterson, M.J.; Ryon, M.G.; Schilling, E.M.; Smith, J.G.; Southworth, G.R.; Stewart, A.J. ); Gatz, A.J. )

    1991-01-01

    On May 1985, a Biological Monitoring Program was developed for East Fork Poplar Creek (EFPC) in eastern Tennessee, United States. This stream originates within the Oak Ridge Y-12 Plant that produces nuclear weapons components for the Department of Energy. Water and sediment in the stream contain metals, organic chemicals, and radionuclides from releases that have occurred over the past 45 years. The creek also receives urban and some agricultural runoff and effluent from the City of Oak Ridge's Wastewater Treatment Facility (WTF). The biological monitoring program includes four major tasks: (1) ambient toxicity testing: (2) bioaccumulation studies; (3) biological indicator studies; and (4) ecological monitoring of stream communities, including periphyton, benthic macroinvertebrates, and fish. Biological conditions are monitored at six sites on EFPC ranging from kilometer 24.4 near the headwaters to kilometer 6.3 near the month. A site on Brushy Fork, A stream just north of Oak Ridge, is used as reference. Ambient (instream) toxicity was monitored through the use of 7-day static-renewal tests that measured the survival and growth of fathead minnow (Pimephales promelas) larvae and the survival and reproduction of a microstrustacean (Ceriodaphnia dubia). Full-strength water from EFPC within the Y-12 Plant boundary was frequently toxic to Ceriodaphnia, but less frequently toxic to the minnow larvae. Chlorine has been identified as an important toxicant in upper EFPC. Water samples from six sites in EFPC downstream from the Y-12 Plant boundary were tested eight times with both species during a 2-year period (October, 1986 through October, 1988). These sites were ranked by the number of times they were best'' or worst'' for each species. Water samples collected for use in the ambient toxicity tests were routinely analyzed for conductivity, pH, alkalinity, hardness, total residual and free chlorine, and temperature.

  11. Tennessee`s East Fork Poplar Creek: A biological monitoring and abatement program

    SciTech Connect

    Halbrook, R.S.; Loar, J.M.; Adams, S.M.; Black, M.C.; Boston, H.L.; Greeley, M.S. Jr.; Hill, W.R.; Hinzman, R.L.; McCarthy, J.F.; Peterson, M.J.; Ryon, M.G.; Schilling, E.M.; Smith, J.G.; Southworth, G.R.; Stewart, A.J.; Gatz, A.J.

    1991-12-31

    On May 1985, a Biological Monitoring Program was developed for East Fork Poplar Creek (EFPC) in eastern Tennessee, United States. This stream originates within the Oak Ridge Y-12 Plant that produces nuclear weapons components for the Department of Energy. Water and sediment in the stream contain metals, organic chemicals, and radionuclides from releases that have occurred over the past 45 years. The creek also receives urban and some agricultural runoff and effluent from the City of Oak Ridge`s Wastewater Treatment Facility (WTF). The biological monitoring program includes four major tasks: (1) ambient toxicity testing: (2) bioaccumulation studies; (3) biological indicator studies; and (4) ecological monitoring of stream communities, including periphyton, benthic macroinvertebrates, and fish. Biological conditions are monitored at six sites on EFPC ranging from kilometer 24.4 near the headwaters to kilometer 6.3 near the month. A site on Brushy Fork, A stream just north of Oak Ridge, is used as reference. Ambient (instream) toxicity was monitored through the use of 7-day static-renewal tests that measured the survival and growth of fathead minnow (Pimephales promelas) larvae and the survival and reproduction of a microstrustacean (Ceriodaphnia dubia). Full-strength water from EFPC within the Y-12 Plant boundary was frequently toxic to Ceriodaphnia, but less frequently toxic to the minnow larvae. Chlorine has been identified as an important toxicant in upper EFPC. Water samples from six sites in EFPC downstream from the Y-12 Plant boundary were tested eight times with both species during a 2-year period (October, 1986 through October, 1988). These sites were ranked by the number of times they were ``best`` or ``worst`` for each species. Water samples collected for use in the ambient toxicity tests were routinely analyzed for conductivity, pH, alkalinity, hardness, total residual and free chlorine, and temperature.

  12. Local adaptation in the flowering-time gene network of balsam poplar, Populus balsamifera L.

    PubMed

    Keller, Stephen R; Levsen, Nicholas; Olson, Matthew S; Tiffin, Peter

    2012-10-01

    Identifying the signature and targets of local adaptation is an increasingly important goal in empirical population genetics. Using data from 443 balsam poplar Populus balsamifera trees sampled from 31 populations, we tested for evidence of geographically variable selection shaping diversity at 27 homologues of the Arabidopsis flowering-time network. These genes are implicated in the control of seasonal phenology, an important determinant of fitness. Using 335 candidate and 412 reference single nucleotide polymorphisms (SNPs), we tested for evidence of local adaptation by searching for elevated population differentiation using F(ST)-based outlier analyses implemented in BayeScan or a Hierarchical Model in Arelquin and by testing for significant associations between allele frequency and environmental variables using BAYENV. A total of 46 SNPs from 14 candidate genes had signatures of local adaptation-either significantly greater population differentiation or significant covariance with one or more environmental variable relative to reference SNP distributions. Only 11 SNPs from two genes exhibited both elevated population differentiation and covariance with one or more environmental variables. Several genes including the abscisic acid gene ABI1B and the circadian clock genes ELF3 and GI5 harbored a large number of SNPs with signatures of local adaptation-with SNPs in GI5 strongly covarying with both latitude and precipitation and SNPs in ABI1B strongly covarying with temperature. In contrast to several other systems, we find little evidence that photoreceptors, including phytochromes, play an important role in local adaptation. Our results additionally show that detecting local adaptation is sensitive to the analytical approaches used and that model-based significance thresholds should be viewed with caution.

  13. Flavitalea populi gen. nov., sp. nov., isolated from soil of a Euphrates poplar (Populus euphratica) forest.

    PubMed

    Wang, Yang; Cai, Feng; Tang, Yali; Dai, Jun; Qi, Huan; Rahman, Erkin; Peng, Fang; Fang, Chengxiang

    2011-07-01

    A novel strain, designated HY-50R(T), isolated from soil of a Euphrates poplar (Populus euphratica) forest in Xinjiang, China, was characterized using a polyphasic taxonomic approach. Cells of the isolate were gram-reaction-negative, strictly aerobic, rod-shaped, non-motile, oxidase-negative and catalase-positive. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate was a member of the phylum Bacteroidetes, its closest relatives being Niastella populi THYL-44(T) (93.6 % similarity), Flavisolibacter ginsengisoli Gsoil 643(T) (93.5 %), Terrimonas ferruginea IAM 15098(T) (93.3 %) and Flavisolibacter ginsengiterrae Gsoil 492(T) (93.2 %). The major fatty acids were iso-C(15 : 1) G (11.7 %), iso-C(15 : 0) (19.6 %) and iso-C(17 : 0) 3-OH (19.3 %). The predominant menaquinone of strain HY-50R(T) was MK-7 and the genomic DNA G+C content was 46.8 mol%. Flexirubin-type pigments were not produced. Based on phylogenetic evidence and the results of phenotypic, genotypic and chemotaxonomic analysis, strain HY-50R(T) represents a novel species of a novel genus, for which the name Flavitalea populi gen. nov., sp. nov. is proposed. The type strain is HY-50R(T) ( = CCTCC AB 208255(T)  = NRRL B-59222(T)).

  14. Hydrolyzable tannins as "quantitative defenses": limited impact against Lymantria dispar caterpillars on hybrid poplar.

    PubMed

    Barbehenn, Raymond V; Jaros, Adam; Lee, Grace; Mozola, Cara; Weir, Quentin; Salminen, Juha-Pekka

    2009-04-01

    The high levels of tannins in many tree leaves are believed to cause decreased insect performance, but few controlled studies have been done. This study tested the hypothesis that higher foliar tannin levels produce higher concentrations of semiquinone radicals (from tannin oxidation) in caterpillar midguts, and that elevated levels of radicals are associated with increased oxidative stress in midgut tissues and decreased larval performance. The tannin-free leaves of hybrid poplar (Populus tremulaxP. alba) were treated with hydrolyzable tannins, producing concentrations of 0%, 7.5% or 15% dry weight, and fed to Lymantria dispar caterpillars. As expected, larvae that ingested control leaves contained no measurable semiquinone radicals in the midgut, those that ingested 7.5% hydrolyzable tannin contained low levels of semiquinone radicals, and those that ingested 15% tannin contained greatly increased levels of semiquinone radicals. Ingested hydrolyzable tannins were also partially hydrolyzed in the midgut. However, increased levels of semiquinone radicals in the midgut were not associated with oxidative stress in midgut tissues. Instead, it appears that tannin consumption was associated with increased metabolic costs, as measured by the decreased efficiency of conversion of digested matter to body mass (ECD). Decreased ECD, in turn, decreased the overall efficiency of conversion of ingested matter to body mass (ECI). Contrary to our hypothesis, L. dispar larvae were able to maintain similar growth rates across all tannin treatment levels, in part, because of compensatory feeding. We conclude that hydrolyzable tannins act as "quantitative defenses" in the sense that high levels appear to be necessary to increase levels of semiquinone radicals in the midguts of caterpillars. However, these putative resistance factors are not sufficient to decrease the performance of tannin-tolerant caterpillars such as L. dispar.

  15. Spliceosomal introns in the 5′ untranslated region of plant BTL RING-H2 ubiquitin ligases are evolutionary conserved and required for gene expression

    PubMed Central

    2013-01-01

    Background Introns located close to the 5′ end of a gene or in the 5′ untranslated region often exert positive effects on gene expression. This effect, known as intron-mediated enhancement (IME), has been observed in diverse eukaryotic organisms, including plants. The sequences involved in IME seem to be spread across the intron and function in an additive manner. The IMEter algorithm was developed to predict plant introns that may enhance gene expression. We have identified several plant members of the BTL class of E3s, which may have orthologs across eukaryotes, that contain a 5′UTR intron. The RING finger E3 ligases are key enzymes of the ubiquitination system that mediate the transfer of ubiquitin to substrates. Results In this study, we retrieved BTL sequences from several angiosperm species and found that 5′UTR introns showing a strong IMEter score were predicted, suggesting that they may be conserved by lineage. Promoter-GUS fusion lines were used to confirm the IME effect of these 5′UTR introns on gene expression. IMEter scores of BTLs were compared with the 5′UTR introns of two gene families MHX and polyubiquitin genes. Conclusions Analysis performed in two Arabidopsis BTL E3 ligases genes indicated that the 5′UTR introns were essential for gene expression in all the tissues tested. Comparison of the average 5′UTR intron size on three gene families in ten angiosperm species suggests that a prevalent size for a 5′UTR intron is in the range of 600 nucleotides, and that the overall IMEter score within a gene family is preserved across several angiosperms. Our results indicated that gene expression dependent on a 5′UTR intron is an efficient regulatory mechanism in BTL E3 ligases that has been preserved throughout plant evolution. PMID:24228887

  16. The fate of tandemly duplicated genes assessed by the expression analysis of a group of Arabidopsis thaliana RING-H2 ubiquitin ligase genes of the ATL family.

    PubMed

    Aguilar-Hernández, Victor; Guzmán, Plinio

    2014-03-01

    Gene duplication events exert key functions on gene innovations during the evolution of the eukaryotic genomes. A large portion of the total gene content in plants arose from tandem duplications events, which often result in paralog genes with high sequence identity. Ubiquitin ligases or E3 enzymes are components of the ubiquitin proteasome system that function during the transfer of the ubiquitin molecule to the substrate. In plants, several E3s have expanded in their genomes as multigene families. To gain insight into the consequences of gene duplications on the expansion and diversification of E3s, we examined the evolutionary basis of a cluster of six genes, duplC-ATLs, which arose from segmental and tandem duplication events in Brassicaceae. The assessment of the expression suggested two patterns that are supported by lineage. While retention of expression domains was observed, an apparent absence or reduction of expression was also inferred. We found that two duplC-ATL genes underwent pseudogenization and that, in one case, gene expression is probably regained. Our findings provide insights into the evolution of gene families in plants, defining key events on the expansion of the Arabidopsis Tóxicos en Levadura family of E3 ligases.

  17. Genome-wide identification, evolution and expression analysis of RING finger protein genes in Brassica rapa

    PubMed Central

    Alam, Intikhab; Yang, Yan-Qing; Wang, Yong; Zhu, Mei-Lan; Wang, Heng-Bo; Chalhoub, Boulos; Lu, Yun-Hai

    2017-01-01

    More and more RING finger genes were found to be implicated in various important biological processes. In the present study, a total of 731 RING domains in 715 predicted proteins were identified in Brassica rapa genome (AA, 2n = 20), which were further divided into eight types: RING-H2 (371), RING-HCa (215), RING-HCb (47), RING-v (44), RING-C2 (38), RING-D (10), RING-S/T (5) and RING-G (1). The 715 RING finger proteins were further classified into 51 groups according to the presence of additional domains. 700 RING finger protein genes were mapped to the 10 chromosomes of B. rapa with a range of 47 to 111 genes for each chromosome. 667 RING finger protein genes were expressed in at least one of the six tissues examined, indicating their involvement in various physiological and developmental processes in B. rapa. Hierarchical clustering analysis of RNA-seq data divided them into seven major groups, one of which includes 231 members preferentially expressed in leaf, and constitutes then a panel of gene candidates for studying the genetic and molecular mechanisms of leafy head traits in Brassica crops. Our results lay the foundation for further studies on the classification, evolution and putative functions of RING finger protein genes in Brassica species. PMID:28094809

  18. Remedial investigation/feasibility study of the Clinch River/Poplar Creek operable unit. Volume 1: Main text

    SciTech Connect

    1996-06-01

    This report presents the findings of an investigation into contamination of the Clinch River and Poplar Creek near the US Department of Energy`s (DOE`s) Oak Ridge Reservation (ORR) in eastern Tennessee. For more than 50 years, various hazardous and radioactive substances have been released to the environment as a result of operations and waste management activities at the ORR. In 1989, the ORR was placed on the National Priorities List (NPL), established and maintained under the federal Comprehensive environmental Response, Compensation, and Liability Act of 1980 (CERCLA). Under CERCLA, NPL sites must be investigated to determine the nature and extent of contamination at the site, assess the risk to human health and the environment posed by the site, and, if necessary, identify feasible remedial alternatives that could be used to clean the site and reduce risk. To facilitate the overall environmental restoration effort at the ORR, CERCLA activities are being implemented individually as distinct operable units (OUs). This document is the combined Remedial Investigation and Feasibility Study Report for the Clinch River/Poplar Creek OU.

  19. Resilience of the rhizosphere Pseudomonas and ammonia-oxidizing bacterial populations during phytoextraction of heavy metal polluted soil with poplar.

    PubMed

    Frey, Beat; Pesaro, Manuel; Rüdt, Andreas; Widmer, Franco

    2008-06-01

    We assessed the effects of phytoextraction on the dynamics of Pseudomonas spp. and ammonia-oxidizing bacterial populations in a heavy metal (HM) polluted soil. Hybrid poplars were grown in two-compartment root containers with a medium history (> 4 years) of HM pollution for 13 weeks. Bulk and poplar rhizosphere soils were analysed by denaturing gradient gel electrophoresis (DGGE) of Pseudomonas (sensu stricto) 16S rRNA and amoA gene fragments. DGGE patterns revealed that Pseudomonas and amoA-containing populations in the contaminated soils were markedly different from those in the uncontaminated soils. Pseudomonas and amoA profiles appeared to be stable over time in the bulk soils. In contrast, contaminated rhizosphere soils revealed a clear shift of populations with removal of HM becoming similar or at least shifted to the populations of the uncontaminated soils. The effect of phytoextraction was, however, not evident in the bulk samples, which still contained large amounts of HM. Cloning and sequencing of dominant DGGE bands revealed that Pseudomonas were phylogenetically related to the Pseudomonas fluorescens cluster and the amoA sequences to Nitrosospira spp. At the last sampling, major prominent band sequences from contaminated rhizosphere soils were identical to sequences obtained from uncontaminated rhizosphere soils, indicating that the populations were dominated by the same phylotypes. This study suggests that two taxonomically different populations are able to recover after the relief of HM stress by phytoextraction practices, whereas bulk microbial activities still remained depressed.

  20. Effect of poultry litter biochar on Saccharomyces cerevisiae growth and ethanol production from steam-exploded poplar and corn stover

    NASA Astrophysics Data System (ADS)

    Diallo, Oumou

    The use of ethanol produced from lignocellulosic biomass for transportation fuel offers solutions in reducing environmental emission and the use of non-renewable fuels. However, lignocellulosic ethanol production is still hampered by economic and technical obstacles. For instance, the inhibitory effect of toxic compounds produced during biomass pretreatment was reported to inhibit the fermenting microorganisms, hence there was a decrease in ethanol yield and productivity. Thus, there is a need to improve the bioconversion of lignocellulosic biomass to ethanol in order to promote its commercialization. The research reported here investigated the use of poultry litter biochar to improve the ethanol production from steam-exploded poplar and corn stover. The effect of poultry litter biochar was first studied on Saccharomyces cerevisiae ATCC 204508/S288C growth, and second on the enzyme hydrolysis and fermentation of two steam-exploded biomasses: (poplar and corn stover). The third part of the study investigated optimal process parameters (biochar loading, biomass loading, and enzyme loading) on the reducing sugars production, and ethanol yield from steam-exploded corn stover. In this study, it has been shown that poultry litter biochar improved the S. cerevisiae growth and ethanol productivity; therefore poultry litter biochar could potentially be used to improve the ethanol production from steam-exploded lignocellulosic biomass.

  1. Different behaviours in phytoremediation capacity of two heavy metal tolerant poplar clones in relation to iron and other trace elements.

    PubMed

    Baldantoni, Daniela; Cicatelli, Angela; Bellino, Alessandro; Castiglione, Stefano

    2014-12-15

    Plant biodiversity and intra-population genetic variability have not yet been properly exploited in the framework of phytoremediation and soil reclamation. For this reason, iron and other metal accumulation capacity of two Cu and Zn tolerant poplar clones, namely AL22 (Populus alba L.) and N12 (Populus nigra L.), was investigated in a pot experiment. Cuttings of the two clones were planted in iron rich soil collected from an urban-industrial area. Concentrations of Cd, Cu, Fe, Pb and Zn were analysed in leaves (at different times), as well as in stems and in roots (at the end of the experiment), both in control plants and in plants grown on a soil whose Fe availability was artificially enhanced. Results showed that Cd and Zn were preferentially accumulated in leaves, whereas Cu, Fe and Pb were mainly accumulated in roots. The main differences in metal accumulation between clones were related to Cd (about tenfold higher concentrations in N12) and Cu (higher concentrations in AL22). Once soil Fe availability was enhanced, the uptake and accumulation of all metals declined, with the exception of Fe at the first sampling time in AL22 leaves. The different behaviour of the two poplar clones suggests that a thoughtful choice should be made for their use in relation to soil heavy metal remediation.

  2. Best management practices plan for the Lower East Fork Poplar Creek remedial action project, Oak Ridge, Tennessee

    SciTech Connect

    1996-08-01

    The U.S. Department of Energy (DOE) has three major operating facilities on the DOE Oak Ridge Reservation (ORR) in Oak Ridge, Tennessee: the Oak Ridge Y-12 Plant, the K-25 Site, and the Oak Ridge National Laboratory (ORNL) managed by Lockheed Martin Environmental Research Corporation. All facilities are managed by Lockheed Martin Energy Systems, Incorporated (Energy Systems) for the DOE. The Y-12 Plant is adjacent to the city of Oak Ridge and is also upstream from Oak Ridge along East Fork Poplar Creek. The portion of the creek downstream from the Y-12 Plant is Lower East Fork Poplar Creek (LEFPC). This project will remove mercury-contaminated soils from the LEFPC floodplain, transport the soils to Industrial Landfill V (ILF-V), and restore any affected areas. This project contains areas that were designated in 1989 as a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) site. The site includes DOE property and portions of commercial, residential, agricultural, and miscellaneous areas within the city of Oak Ridge.

  3. Initial frequency of alleles conferring resistance to Bacillus thuringiensis poplar in a field population of Chrysomela tremulae.

    PubMed Central

    Génissel, Anne; Augustin, Sylvie; Courtin, Claudine; Pilate, Gilles; Lorme, Philippe; Bourguet, Denis

    2003-01-01

    Globally, the estimated total area planted with transgenic plants producing Bacillus thuringiensis (Bt) toxins was 12 million hectares in 2001. The risk of target pests becoming resistant to these toxins has led to the implementation of resistance-management strategies. The efficiency and sustainability of these strategies, including the high-dose plus refuge strategy currently recommended for North American maize, depend on the initial frequency of resistance alleles. In this study, we estimated the initial frequencies of alleles conferring resistance to transgenic Bt poplars producing Cry3A in a natural population of the poplar pest Chrysomela tremulae (Coleoptera: Chrysomelidae). We used the F(2) screen method developed for detecting resistance alleles in natural pest populations. At least three parents of the 270 lines tested were heterozygous for a major Bt resistance allele. We estimated mean resistance-allele frequency for the period 1999-2001 at 0.0037 (95% confidence interval = 0.00045-0.0080) with a detection probability of 90%. These results demonstrate that (i) the F(2) screen method can be used to detect major alleles conferring resistance to Bt-producing plants in insects and (ii) the initial frequency of alleles conferring resistance to Bt toxin can be close to the highest theoretical values that are expected prior to the use of Bt plants if considering fitness costs and typical mutation rates. PMID:12737656

  4. Multiplication and growth of hybrid poplar (Populus alba × P. tremula) shoots on a hormone-free medium.

    PubMed

    Ziauka, J; Kuusienė, Sigutė

    2014-09-01

    The present study explored an alternative approach for poplar micropropagation, based on the restriction of gas exchange between inside and outside environments of culture vessel, rather than on the application of exogenous hormones. Apical and nodal stem segments (explants) excised from in vitro-developed shoots of hybrid white poplar (Populus alba L. × P. tremula L.) were incubated in either sealed (with Parafilm) or unsealed capped glass culture tubes (150 × 20 mm) on a hormone-free Woody Plant Medium. Shoot proliferation on apical explants was observed in sealed culture tubes but not in the unsealed ones; the difference between these two samples in respect of shoot number increased in the course of time and became threefold after three months of culture, with 3.2 ± 0.4 (mean ± SE) shoots per explant in the sealed tubes versus 1.1 ± 0.1 in the unsealed ones (for comparison, the mean shoot numbers on nodal explants were 2.4 ± 0.3 and 3.4 ± 0.4 in the unsealed and sealed culture tubes, respectively). Moreover, the shoots taken from the sealed culture tubes could be distinguished by superior shoot length, if compared to the shoots from the unsealed tubes, during the subsequent culture stage under uniform conditions.

  5. Differentiation of Populus species using chloroplast single nucleotide polymorphism (SNP) markers--essential for comprehensible and reliable poplar breeding.

    PubMed

    Schroeder, H; Hoeltken, A M; Fladung, M

    2012-03-01

    Within the genus Populus several species belonging to different sections are cross-compatible. Hence, high numbers of interspecies hybrids occur naturally and, additionally, have been artificially produced in huge breeding programmes during the last 100 years. Therefore, determination of a single poplar species, used for the production of 'multi-species hybrids' is often difficult, and represents a great challenge for the use of molecular markers in species identification. Within this study, over 20 chloroplast regions, both intergenic spacers and coding regions, have been tested for their ability to differentiate different poplar species using 23 already published barcoding primer combinations and 17 newly designed primer combinations. About half of the published barcoding primers yielded amplification products, whereas the new primers designed on the basis of the total sequenced cpDNA genome of Populus trichocarpa Torr. & Gray yielded much higher amplification success. Intergenic spacers were found to be more variable than coding regions within the genus Populus. The highest discrimination power of Populus species was found in the combination of two intergenic spacers (trnG-psbK, psbK-psbl) and the coding region rpoC. In barcoding projects, the coding regions matK and rbcL are often recommended, but within the genus Populus they only show moderate variability and are not efficient in species discrimination.

  6. Expression of glutathione S-transferases in poplar trees (Populus trichocarpa) exposed to 2,4,6-trinitrotoluene (TNT).

    PubMed

    Brentner, Laura B; Mukherji, Sachiyo T; Merchie, Kate M; Yoon, Jong Moon; Schnoor, Jerald L; Van Aken, Benoit

    2008-10-01

    Twelve Populus genes were identified from Arabidopsis thaliana sequences previously shown to be induced by exposure to 2,4,6-trinitrotoluene (TNT). Using the resources of the Poplar Genome Project and National Center for Biotechnology Information databases, Populus conserved domains were identified and used to design gene specific primers. RNA extracted from root tissues of TNT-exposed hydroponic poplar plants was used to quantify the expression of genes by reverse-transcriptase real-time polymerase chain reaction. Cyclophilin and 18S ribosomal DNA genes were used as internal standards. Exposure to TNT resulted in a significant increase of gene expression of two glutathione S-transferases (GST), peaking at levels of 25.0 +/- 13.1 and 10 +/- 0.7 fold the expression level of non-exposed plants after 24 h for each of the GST genes, respectively. This paper demonstrates the use of functional genomics information from the model plant species, Arabidopsis, to identify genes which may be important in detoxification of TNT in the model phytoremediation species, Populus trichocarpa.

  7. Productivity of poplar grown on short rotation in Spain: Influence of the rotation age and plant density

    SciTech Connect

    Ciria, M.P.; Mazon, P.; Carrasco, J.

    1995-11-01

    The objective of this work is to evaluate the growth potential and biomass productivity of poplar on short rotation for different growth cycles and plant densities in southern Europe. Five poplar clones have been tested: Unal, Beaupre, Hunnegen, Boelare and Raspalje, all are hybrid clones P. trichocarpa x P. deltoides. For each clone, plant densities of 10000, 5000, 2500 and 1666 trees/ha have been assayed, for growth cycles of 2, 3, 4 and 5 years. The experimentation was initiated in 1986 at Castilla y Leon, region in Spain. The situation of the plantation is 41{degrees}36`N and 2{degrees}30`E (Greenwich meridiane), at an altitude of 1010 m above the sea level. The average rain precipitation is of about 550 mm/year and the average temperature, 10.5{degrees}C. The parameters evaluated for each plant after harvesting have been: total dry weight of the aerial part and dry weight, height and basal diameter of the stems. The highest biomass productivity, next to 20 t/ha.year, was achieved for Raspalje clone, utilizing 10000 trees/ha plantation density and growth cycle of 5 years. Under these conditions the average diameter of the stems was 9.5 cm and the average height of the trees was 7.9 m.

  8. Transcript and metabolite profiling for the evaluation of tobacco tree and poplar as feedstock for the bio-based industry.

    PubMed

    Ruprecht, Colin; Tohge, Takayuki; Fernie, Alisdair; Mortimer, Cara L; Kozlo, Amanda; Fraser, Paul D; Funke, Norma; Cesarino, Igor; Vanholme, Ruben; Boerjan, Wout; Morreel, Kris; Burgert, Ingo; Gierlinger, Notburga; Bulone, Vincent; Schneider, Vera; Stockero, Andrea; Navarro, Juan Pedro; Pudel, Frank; Tambuyser, Bart; Hygate, James; Bumstead, Jon; Notley, Louis; Persson, Staffan

    2014-05-16

    The global demand for food, feed, energy and water poses extraordinary challenges for future generations. It is evident that robust platforms for the exploration of renewable resources are necessary to overcome these challenges. Within the multinational framework MultiBioPro we are developing biorefinery pipelines to maximize the use of plant biomass. More specifically, we use poplar and tobacco tree (Nicotiana glauca) as target crop species for improving saccharification, isoprenoid, long chain hydrocarbon contents, fiber quality, and suberin and lignin contents. The methods used to obtain these outputs include GC-MS, LC-MS and RNA sequencing platforms. The metabolite pipelines are well established tools to generate these types of data, but also have the limitations in that only well characterized metabolites can be used. The deep sequencing will allow us to include all transcripts present during the developmental stages of the tobacco tree leaf, but has to be mapped back to the sequence of Nicotiana tabacum. With these set-ups, we aim at a basic understanding for underlying processes and at establishing an industrial framework to exploit the outcomes. In a more long term perspective, we believe that data generated here will provide means for a sustainable biorefinery process using poplar and tobacco tree as raw material. To date the basal level of metabolites in the samples have been analyzed and the protocols utilized are provided in this article.

  9. Cellulose and lignin biosynthesis is altered by ozone in wood of hybrid poplar (Populus tremula × alba).

    PubMed

    Richet, Nicolas; Afif, Dany; Huber, Françoise; Pollet, Brigitte; Banvoy, Jacques; El Zein, Rana; Lapierre, Catherine; Dizengremel, Pierre; Perré, Patrick; Cabané, Mireille

    2011-06-01

    Wood formation in trees is a dynamic process that is strongly affected by environmental factors. However, the impact of ozone on wood is poorly documented. The objective of this study was to assess the effects of ozone on wood formation by focusing on the two major wood components, cellulose and lignin, and analysing any anatomical modifications. Young hybrid poplars (Populus tremula × alba) were cultivated under different ozone concentrations (50, 100, 200, and 300 l l(-1)). As upright poplars usually develop tension wood in a non-set pattern, the trees were bent in order to induce tension wood formation on the upper side of the stem and normal or opposite wood on the lower side. Biosynthesis of cellulose and lignin (enzymes and RNA levels), together with cambial growth, decreased in response to ozone exposure. The cellulose to lignin ratio was reduced, suggesting that cellulose biosynthesis was more affected than that of lignin. Tension wood was generally more altered than opposite wood, especially at the anatomical level. Tension wood may be more susceptible to reduced carbon allocation to the stems under ozone exposure. These results suggested a coordinated regulation of cellulose and lignin deposition to sustain mechanical strength under ozone. The modifications of the cellulose to lignin ratio and wood anatomy could allow the tree to maintain radial growth while minimizing carbon cost.

  10. Transcript and Metabolite Profiling for the Evaluation of Tobacco Tree and Poplar as Feedstock for the Bio-based Industry

    PubMed Central

    Ruprecht, Colin; Tohge, Takayuki; Fernie, Alisdair; Mortimer, Cara L.; Kozlo, Amanda; Fraser, Paul D.; Funke, Norma; Cesarino, Igor; Vanholme, Ruben; Boerjan, Wout; Morreel, Kris; Burgert, Ingo; Gierlinger, Notburga; Bulone, Vincent; Schneider, Vera; Stockero, Andrea; Navarro, Juan Pedro; Pudel, Frank; Tambuyser, Bart; Hygate, James; Bumstead, Jon; Notley, Louis; Persson, Staffan

    2014-01-01

    The global demand for food, feed, energy, and water poses extraordinary challenges for future generations. It is evident that robust platforms for the exploration of renewable resources are necessary to overcome these challenges. Within the multinational framework MultiBioPro we are developing biorefinery pipelines to maximize the use of plant biomass. More specifically, we use poplar and tobacco tree (Nicotiana glauca) as target crop species for improving saccharification, isoprenoid, long chain hydrocarbon contents, fiber quality, and suberin and lignin contents. The methods used to obtain these outputs include GC-MS, LC-MS and RNA sequencing platforms. The metabolite pipelines are well established tools to generate these types of data, but also have the limitations in that only well characterized metabolites can be used. The deep sequencing will allow us to include all transcripts present during the developmental stages of the tobacco tree leaf, but has to be mapped back to the sequence of Nicotiana tabacum. With these set-ups, we aim at a basic understanding for underlying processes and at establishing an industrial framework to exploit the outcomes. In a more long term perspective, we believe that data generated here will provide means for a sustainable biorefinery process using poplar and tobacco tree as raw material. To date the basal level of metabolites in the samples have been analyzed and the protocols utilized are provided in this article. PMID:24894952

  11. Long-term biomonitoring of soil contamination using poplar trees: accumulation of trace elements in leaves and fruits.

    PubMed

    Madejón, P; Ciadamidaro, L; Marañón, T; Murillo, J M

    2013-01-01

    Phytostabilization aims to immobilize soil contaminants using higher plants. The accumulation of trace elements in Populus alba leaves was monitored for 12 years after a mine spill. Concentrations of As and Pb significantly decreased, while concentrations of Cd and Zn did not significantly over time. Soil concentrations extracted by CaCl2 were measured by ICP-OES and results of As and Pb were below the detection limit. Long-term biomonitoring of soil contamination using poplar leaves was proven to be better suited for the study of trace elements. Plants suitable for phytostabilization must also be able to survive and reproduce in contaminated soils. Concentrations of trace elements were also measured in P. alba fruiting catkins to determine the effect on its reproduction potential. Cadmium and Zn were found to accumulate in fruiting catkins, with the transfer coefficient for Cd significantly greater than Zn. It is possible for trace elements to translocate to seed, which presents a concern for seed germination, establishment and colonization. We conclude that white poplar is a suitable tree for long-term monitoring of soil contaminated with Cd and Zn, and for phytostabilization in riparian habitats, although some caution should be taken with the possible effects on the food web. Supplemental materials are available for this article. Go to the publisher's online edition of International Journal of Phytoremediation to view the supplemental file.

  12. Cellulose and lignin biosynthesis is altered by ozone in wood of hybrid poplar (Populus tremula×alba)

    PubMed Central

    Richet, Nicolas; Afif, Dany; Huber, Françoise; Pollet, Brigitte; Banvoy, Jacques; El Zein, Rana; Lapierre, Catherine; Dizengremel, Pierre; Perré, Patrick; Cabané, Mireille

    2011-01-01

    Wood formation in trees is a dynamic process that is strongly affected by environmental factors. However, the impact of ozone on wood is poorly documented. The objective of this study was to assess the effects of ozone on wood formation by focusing on the two major wood components, cellulose and lignin, and analysing any anatomical modifications. Young hybrid poplars (Populus tremula×alba) were cultivated under different ozone concentrations (50, 100, 200, and 300 nl l−1). As upright poplars usually develop tension wood in a non-set pattern, the trees were bent in order to induce tension wood formation on the upper side of the stem and normal or opposite wood on the lower side. Biosynthesis of cellulose and lignin (enzymes and RNA levels), together with cambial growth, decreased in response to ozone exposure. The cellulose to lignin ratio was reduced, suggesting that cellulose biosynthesis was more affected than that of lignin. Tension wood was generally more altered than opposite wood, especially at the anatomical level. Tension wood may be more susceptible to reduced carbon allocation to the stems under ozone exposure. These results suggested a coordinate