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Sample records for plant populus trichocarpa

  1. Evolutionary Quantitative Genomics of Populus trichocarpa.

    Science.gov (United States)

    Porth, Ilga; Klápště, Jaroslav; McKown, Athena D; La Mantia, Jonathan; Guy, Robert D; Ingvarsson, Pär K; Hamelin, Richard; Mansfield, Shawn D; Ehlting, Jürgen; Douglas, Carl J; El-Kassaby, Yousry A

    2015-01-01

    Forest trees generally show high levels of local adaptation and efforts focusing on understanding adaptation to climate will be crucial for species survival and management. Here, we address fundamental questions regarding the molecular basis of adaptation in undomesticated forest tree populations to past climatic environments by employing an integrative quantitative genetics and landscape genomics approach. Using this comprehensive approach, we studied the molecular basis of climate adaptation in 433 Populus trichocarpa (black cottonwood) genotypes originating across western North America. Variation in 74 field-assessed traits (growth, ecophysiology, phenology, leaf stomata, wood, and disease resistance) was investigated for signatures of selection (comparing QST-FST) using clustering of individuals by climate of origin (temperature and precipitation). 29,354 SNPs were investigated employing three different outlier detection methods and marker-inferred relatedness was estimated to obtain the narrow-sense estimate of population differentiation in wild populations. In addition, we compared our results with previously assessed selection of candidate SNPs using the 25 topographical units (drainages) across the P. trichocarpa sampling range as population groupings. Narrow-sense QST for 53% of distinct field traits was significantly divergent from expectations of neutrality (indicating adaptive trait variation); 2,855 SNPs showed signals of diversifying selection and of these, 118 SNPs (within 81 genes) were associated with adaptive traits (based on significant QST). Many SNPs were putatively pleiotropic for functionally uncorrelated adaptive traits, such as autumn phenology, height, and disease resistance. Evolutionary quantitative genomics in P. trichocarpa provides an enhanced understanding regarding the molecular basis of climate-driven selection in forest trees and we highlight that important loci underlying adaptive trait variation also show relationship to climate

  2. Evolutionary Quantitative Genomics of Populus trichocarpa.

    Directory of Open Access Journals (Sweden)

    Ilga Porth

    Full Text Available Forest trees generally show high levels of local adaptation and efforts focusing on understanding adaptation to climate will be crucial for species survival and management. Here, we address fundamental questions regarding the molecular basis of adaptation in undomesticated forest tree populations to past climatic environments by employing an integrative quantitative genetics and landscape genomics approach. Using this comprehensive approach, we studied the molecular basis of climate adaptation in 433 Populus trichocarpa (black cottonwood genotypes originating across western North America. Variation in 74 field-assessed traits (growth, ecophysiology, phenology, leaf stomata, wood, and disease resistance was investigated for signatures of selection (comparing QST-FST using clustering of individuals by climate of origin (temperature and precipitation. 29,354 SNPs were investigated employing three different outlier detection methods and marker-inferred relatedness was estimated to obtain the narrow-sense estimate of population differentiation in wild populations. In addition, we compared our results with previously assessed selection of candidate SNPs using the 25 topographical units (drainages across the P. trichocarpa sampling range as population groupings. Narrow-sense QST for 53% of distinct field traits was significantly divergent from expectations of neutrality (indicating adaptive trait variation; 2,855 SNPs showed signals of diversifying selection and of these, 118 SNPs (within 81 genes were associated with adaptive traits (based on significant QST. Many SNPs were putatively pleiotropic for functionally uncorrelated adaptive traits, such as autumn phenology, height, and disease resistance. Evolutionary quantitative genomics in P. trichocarpa provides an enhanced understanding regarding the molecular basis of climate-driven selection in forest trees and we highlight that important loci underlying adaptive trait variation also show

  3. The genome of black cottonwood, Populus trichocarpa (Torr.&Gray)

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    Tuskan, G.A.; DiFazio, S.; Jansson, S.; Bohlmann, J.; Grigoriev,I.; Hellsten, U.; Putnam, N.; Ralph, S.; Rombauts, S.; Salamov, A.; Schein, J.; Sterck, L.; Aerts, A.; Bhalerao, R.R.; Bhalerao, R.P.; Blaudez, D.; Boerjan, W.; Brun, A.; Brunner, A.; Busov, V.; Campbell, M.; Carlson, J.; Chalot, M.; Chapman, J.; Chen, G.-L.; Cooper, D.; Coutinho,P.M.; Couturier, J.; Covert, S.; Cronk, Q.; Cunningham, R.; Davis, J.; Degroeve, S.; Dejardin, A.; dePamphillis, C.; Detter, J.; Dirks, B.; Dubchak, I.; Duplessis, S.; Ehiting, J.; Ellis, B.; Gendler, K.; Goodstein, D.; Gribskov, M.; Grimwood, J.; Groover, A.; Gunter, L.; Hamberger, B.; Heinze, B.; Helariutta, Y.; Henrissat, B.; Holligan, D.; Holt, R.; Huang, W.; Islam-Faridi, N.; Jones, S.; Jones-Rhoades, M.; Jorgensen, R.; Joshi, C.; Kangasjarvi, J.; Karlsson, J.; Kelleher, C.; Kirkpatrick, R.; Kirst, M.; Kohler, A.; Kalluri, U.; Larimer, F.; Leebens-Mack, J.; Leple, J.-C.; Locascio, P.; Lou, Y.; Lucas, S.; Martin,F.; Montanini, B.; Napoli, C.; Nelson, D.R.; Nelson, D.; Nieminen, K.; Nilsson, O.; Peter, G.; Philippe, R.; Pilate, G.; Poliakov, A.; Razumovskaya, J.; Richardson, P.; Rinaldi, C.; Ritland, K.; Rouze, P.; Ryaboy, D.; Schmutz, J.; Schrader, J.; Segerman, B.; Shin, H.; Siddiqui,A.; Sterky, F.; Terry, A.; Tsai, C.; Uberbacher, E.; Unneberg, P.; Vahala, J.; Wall, K.; Wessler, S.; Yang, G.; Yin, T.; Douglas, C.; Marra,M.; Sandberg, G.; Van der Peer, Y.; Rokhsar, D.

    2006-09-01

    We report the draft genome of the black cottonwood tree, Populus trichocarpa. Integration of shotgun sequence assembly with genetic mapping enabled chromosome-scale reconstruction of the genome. Over 45,000 putative protein-coding genes were identified. Analysis of the assembled genome revealed a whole-genome duplication event, with approximately 8,000 pairs of duplicated genes from that event surviving in the Populus genome. A second, older duplication event is indistinguishably coincident with the divergence of the Populus and Arabidopsis lineages. Nucleotide substitution, tandem gene duplication and gross chromosomal rearrangement appear to proceed substantially slower in Populus relative to Arabidopsis. Populus has more protein-coding genes than Arabidopsis, ranging on average between 1.4-1.6 putative Populus homologs for each Arabidopsis gene. However, the relative frequency of protein domains in the two genomes is similar. Overrepresented exceptions in Populus include genes associated with disease resistance, meristem development, metabolite transport and lignocellulosic wall biosynthesis.

  4. The Genome of Black Cottonwood, Populus trichocarpa (Torr. & Gray)

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    Tuskan, Gerald A [ORNL; DiFazio, Stephen P [ORNL; Jansson, Bo S [ORNL; Bohlmann, J. [University of British Columbia, Vancouver; Grigoriev, I. [U.S. Department of Energy, Joint Genome Institute; Hellsten, U. [U.S. Department of Energy, Joint Genome Institute; Putman, N. [U.S. Department of Energy, Joint Genome Institute; Ralph, S. [University of British Columbia, Vancouver; Rombauts, S. [Ghent University, Belgium; Salamov, A. [U.S. Department of Energy, Joint Genome Institute; Schein, J. [Genome Sciences Centre, Vancouver, BC, Canada; Sterck, L. [Ghent University, Belgium; Aerts, A. [U.S. Department of Energy, Joint Genome Institute; Bhalerao, R. R. [Umea Plant Science Centre, Dept. of Plant Physiology, Sweden; Bhalerao, Rishikesh P [ORNL; Blaudez, D. [Institut National de la Recherche Agronomique, France; Boerjan, W. [Ghent University, Belgium; Brun, A. [Institut National de la Recherche Agronomique, France; Brunner, A. [Virginia Polytechnic Institute and State University (Virginia Tech); Busov, V. [Michigan Technological University; Campbell, M. [University of Toronto; Larimer, Frank W [ORNL; Detter, J C [U.S. Department of Energy, Joint Genome Institute; Richardson, P M [U.S. Department of Energy, Joint Genome Institute; Chen, Gwo-Liang [ORNL; Gunter, Lee E [ORNL; Kalluri, Udaya C [ORNL; LoCascio, Philip F [ORNL; Uberbacher, Edward C [ORNL; Yin, Tongming [ORNL

    2006-01-01

    We report the draft genome of the black cottonwood tree, Populus trichocarpa. Integration of shotgun sequence assembly with genetic mapping enabled chromosome-scale reconstruction of the genome. More than 45,000 putative protein-coding genes were identified. Analysis of the assembled genome revealed a whole-genome duplication event; about 8000 pairs of duplicated genes from that event survived in the Populus genome. A second, older duplication event is indistinguishably coincident with the divergence of the Populus and Arabidopsis lineages. Nucleotide substitution, tandem gene duplication, and gross chromosomal rearrangement appear to proceed substantially more slowly in Populus than in Arabidopsis. Populus has more protein-coding genes than Arabidopsis, ranging on average from 1.4 to 1.6 putative Populus homologs for each Arabidopsis gene. However, the relative frequency of protein domains in the two genomes is similar. Overrepresented exceptions in Populus include genes associated with lignocellulosic wall biosynthesis, meristem development, disease resistance, and metabolite transport.

  5. Structural and enzymatic insights into Lambda glutathione transferases from Populus trichocarpa, monomeric enzymes constituting an early divergent class specific to terrestrial plants.

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    Lallement, Pierre-Alexandre; Meux, Edgar; Gualberto, José M; Prosper, Pascalita; Didierjean, Claude; Saul, Frederick; Haouz, Ahmed; Rouhier, Nicolas; Hecker, Arnaud

    2014-08-15

    GSTs represent a superfamily of multifunctional proteins which play crucial roles in detoxification processes and secondary metabolism. Instead of promoting the conjugation of glutathione to acceptor molecules as do most GSTs, members of the Lambda class (GSTLs) catalyse deglutathionylation reactions via a catalytic cysteine residue. Three GSTL genes (Pt-GSTL1, Pt-GSTL2 and Pt-GSTL3) are present in Populus trichocarpa, but two transcripts, differing in their 5' extremities, were identified for Pt-GSTL3. Transcripts for these genes were primarily found in flowers, fruits, petioles and buds, but not in leaves and roots, suggesting roles associated with secondary metabolism in these organs. The expression of GFP-fusion proteins in tobacco showed that Pt-GSTL1 is localized in plastids, whereas Pt-GSTL2 and Pt-GSTL3A and Pt-GSTL3B are found in both the cytoplasm and the nucleus. The resolution of Pt-GSTL1 and Pt-GSTL3 structures by X-ray crystallography indicated that, although these proteins adopt a canonical GST fold quite similar to that found in dimeric Omega GSTs, their non-plant counterparts, they are strictly monomeric. This might explain some differences in the enzymatic properties of both enzyme types. Finally, from competition experiments between aromatic substrates and a fluorescent probe, we determined that the recognition of glutathionylated substrates is favoured over non-glutathionylated forms.

  6. Genome-Wide Analysis of BURP Domain-Containing Genes in Populus trichocarpa

    Institute of Scientific and Technical Information of China (English)

    Yuanhua Shao; Guo Wei; Ling Wang; Qing Dong; Yang Zhao; Beijiu Chen; Yan Xiang

    2011-01-01

    BURP domain-containing proteins have a conserved structure and are found extensively in plants.The functions of the proteins in this family are diverse,but remain unknown in Populus trichocarpa.In the present study,a complete genome of P.trichocarpa was analyzed bioinformatically.A total of 18 BURP family genes,named PtBURPs,were identified and characterized according to their physical positions on the P.trichocarpa chromosomes.A phylogenetic tree was generated from alignments of PtBURP protein sequences,while phylogenetic relationships were also examined between PtBURPs and BURP family genes in other plants,including rice,soybean,maize and sorghum.BURP genes in P.trichocarpa were classified into five classes,namely PG1β-Iike,BNM2-like,USP-like,RD22-like and BURP V.The multiple expectation maximization for motif elicitation (MEME) and multiple protein sequence alignments of PtBURPs were also performed.Results from the transcript level analyses of 10 PtBURP genes under different stress conditions revealed the expression patterns in poplar and led to a discussion on genome duplication and evolution,expression profiles and function of PtBURP genes.

  7. Insights into ascorbate regeneration in plants: investigating the redox and structural properties of dehydroascorbate reductases from Populus trichocarpa.

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    Lallement, Pierre-Alexandre; Roret, Thomas; Tsan, Pascale; Gualberto, José M; Girardet, Jean-Michel; Didierjean, Claude; Rouhier, Nicolas; Hecker, Arnaud

    2016-03-15

    Dehydroascorbate reductases (DHARs), enzymes belonging to the GST superfamily, catalyse the GSH-dependent reduction of dehydroascorbate into ascorbate in plants. By maintaining a reduced ascorbate pool, they notably participate to H2O2 detoxification catalysed by ascorbate peroxidases (APXs). Despite this central role, the catalytic mechanism used by DHARs is still not well understood and there is no supportive 3D structure. In this context, we have performed a thorough biochemical and structural analysis of the three poplar DHARs and coupled this to the analysis of their transcript expression patterns and subcellular localizations. The transcripts for these genes are mainly detected in reproductive and green organs and the corresponding proteins are expressed in plastids, in the cytosol and in the nucleus, but not in mitochondria and peroxisomes where ascorbate regeneration is obviously necessary. Comparing the kinetic properties and the sensitivity to GSSG-mediated oxidation of DHAR2 and DHAR3A, exhibiting 1 or 3 cysteinyl residues respectively, we observed that the presence of additional cysteines in DHAR3A modifies the regeneration mechanism of the catalytic cysteine by forming different redox states. Finally, from the 3D structure of DHAR3A solved by NMR, we were able to map the residues important for the binding of both substrates (GSH and DHA), showing that DHAR active site is very selective for DHA recognition and providing further insights into the catalytic mechanism and the roles of the additional cysteines found in some DHARs.

  8. Isolation and characterization of cDNAs encoding leucoanthocyanidin reductase and anthocyanidin reductase from Populus trichocarpa.

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    Lijun Wang

    Full Text Available Proanthocyanidins (PAs contribute to poplar defense mechanisms against biotic and abiotic stresses. Transcripts of PA biosynthetic genes accumulated rapidly in response to infection by the fungus Marssonina brunnea f.sp. multigermtubi, treatments of salicylic acid (SA and wounding, resulting in PA accumulation in poplar leaves. Anthocyanidin reductase (ANR and leucoanthocyanidin reductase (LAR are two key enzymes of the PA biosynthesis that produce the main subunits: (+-catechin and (--epicatechin required for formation of PA polymers. In Populus, ANR and LAR are encoded by at least two and three highly related genes, respectively. In this study, we isolated and functionally characterized genes PtrANR1 and PtrLAR1 from P. trichocarpa. Phylogenetic analysis shows that Populus ANR1 and LAR1 occurr in two distinct phylogenetic lineages, but both genes have little difference in their tissue distribution, preferentially expressed in roots. Overexpression of PtrANR1 in poplar resulted in a significant increase in PA levels but no impact on catechin levels. Antisense down-regulation of PtrANR1 showed reduced PA accumulation in transgenic lines, but increased levels of anthocyanin content. Ectopic expression of PtrLAR1 in poplar positively regulated the biosynthesis of PAs, whereas the accumulation of anthocyanin and flavonol was significantly reduced (P<0.05 in all transgenic plants compared to the control plants. These results suggest that both PtrANR1 and PtrLAR1 contribute to PA biosynthesis in Populus.

  9. Comprehensive analysis of trihelix genes and their expression under biotic and abiotic stresses in Populus trichocarpa

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    Wang, Zhanchao; Liu, Quangang; Wang, Hanzeng; Zhang, Haizhen; Xu, Xuemei; Li, Chenghao; Yang, Chuanping

    2016-01-01

    Trihelix genes play important roles in plant growth and development and responses to biotic and abiotic stresses. Here, we identified 56 full-length trihelix genes in Populus trichocarpa and classified them into five groups. Most genes within a given group had similar gene structures and conserved motifs. The trihelix genes were unequally distributed across 19 different linkage groups. Fifteen paralogous pairs were identified, 14 of which have undergone segmental duplication events. Promoter cis-element analysis indicated that most trihelix genes contain stress- or phytohormone-related cis-elements. The expression profiles of the trihelix genes suggest that they are primarily expressed in leaves and roots. Quantitative real-time reverse transcription polymerase chain reaction analysis indicated that members of the trihelix gene family are significantly induced in response to osmotic, abscisic acid, salicylic acid, methyl jasmonate and pathogen infection. PtrGT10 was identified as a target gene of miR172d, which is involved in the osmotic response. Repression of PtrGT10 could increase reactive oxygen species scavenging ability and decrease cell death. This study provides novel insights into the phylogenetic relationships and functions of the P. trichocarpa trihelix genes, which will aid future functional studies investigating the divergent roles of trihelix genes belonging to other species. PMID:27782188

  10. RepPop: a database for repetitive elements in Populus trichocarpa

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    Xu Ying

    2009-01-01

    Full Text Available Abstract Background Populus trichocarpa is the first tree genome to be completed, and its whole genome is currently being assembled. No functional annotation about the repetitive elements in the Populus trichocarpa genome is currently available. Results We predicted 9,623 repetitive elements in the Populus trichocarpa genome, and assigned functions to 3,075 of them (31.95%. The 9,623 repetitive elements cover ~40% of the current (partially assembled genome. Among the 9,623 repetitive elements, 668 have copies only in the contigs that have not been assigned to one of the 19 chromosome while the rest all have copies in the partially assembled chromosomes. Conclusion All the predicted data are organized into an easy-to-use web-browsable database, RepPop. Various search capabilities are provided against the RepPop database. A Wiki system has been set up to facilitate functional annotation and curation of the repetitive elements by a community rather than just the database developer. The database RepPop will facilitate the assembling and functional characterization of the Populus trichocarpa genome.

  11. Molecular and biochemical characterization of the jasmonic acid methyltransferase gene from black cottonwood (Populus trichocarpa)

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    Zhao, Nan [ORNL; Yao, Jianzhuang [University of Tennessee, Knoxville (UTK); Chaiprasongsuk, Minta [University of Tennessee, Knoxville (UTK); Li, Guanglin [University of Tennessee, Knoxville (UTK); Guan, Ju [University of Tennessee, Knoxville (UTK); Tschaplinski, Timothy J [ORNL; Guo, Hong [University of Tennessee, Knoxville (UTK); Chen, Feng [University of Tennessee, Knoxville (UTK)

    2013-01-01

    Methyl jasmonate is a metabolite known to be produced by many plants and has roles in diverse biological processes. It is biosynthesized by the action of S-adenosyl-L-methionine:jasmonic acid carboxyl methyltransferase (JMT), which belongs to the SABATH family of methyltransferases. Herein is reported the isolation and biochemical characterization of a JMT gene from black cottonwood (Populus trichocarpa). The genome of P. trichocarpa contains 28 SABATH genes (PtSABATH1 to PtSABATH28). Recombinant PtSABATH3 expressed in Escherichia coli showed the highest level of activity with jasmonic acid (JA) among carboxylic acids tested. It was therefore renamed PtJMT1. PtJMT1 also displayed activity with benzoic acid (BA), with which the activity was about 22% of that with JA. PtSABATH2 and PtSABATH4 were most similar to PtJMT1 among all PtSABATHs. However, neither of them had activity with JA. The apparent Km values of PtJMT1 using JA and BA as substrate were 175 lM and 341 lM, respectively. Mutation of Ser-153 and Asn-361, two residues in the active site of PtJMT1, to Tyr and Ser respectively, led to higher specific activity with BA than with JA. Homology-based structural modeling indicated that substrate alignment, in which Asn-361 is involved, plays a role in determining the substrate specificity of PtJMT1. In the leaves of young seedlings of black cottonwood, the expression of PtJMT1 was induced by plant defense signal molecules methyl jasmonate and salicylic acid and a fungal elicitor alamethicin, suggesting that PtJMT1 may have a role in plant defense against biotic stresses. Phylogenetic analysis suggests that PtJMT1 shares a common ancestor with the Arabidopsis JMT, and functional divergence of these two apparent JMT orthologs has occurred since the split of poplar and Arabidopsis lineages.

  12. Cytogenetic analysis of Populus trichocarpa--ribosomal DNA, telomere repeat sequence, and marker-selected BACs.

    Science.gov (United States)

    Islam-Faridi, M N; Nelson, C D; DiFazio, S P; Gunter, L E; Tuskan, G A

    2009-01-01

    The 18S-28S rDNA and 5S rDNA loci in Populus trichocarpa were localized using fluorescent in situ hybridization (FISH). Two 18S-28S rDNA sites and one 5S rDNA site were identified and located at the ends of 3 different chromosomes. FISH signals from the Arabidopsis-type telomere repeat sequence were observed at the distal ends of each chromosome. Six BAC clones selected from 2 linkage groups based on genome sequence assembly (LG-I and LG-VI) were localized on 2 chromosomes, as expected. BACs from LG-I hybridized to the longest chromosome in the complement. All BAC positions were found to be concordant with sequence assembly positions. BAC-FISH will be useful for delineating each of the Populus trichocarpa chromosomes and improving the sequence assembly of this model angiosperm tree species.

  13. Cytogenetic Analysis of Populus trichocarpa - Ribosomal DNA, Telomere Repeat Sequence, and Marker-selected BACs

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    Tuskan, Gerald A [ORNL; Gunter, Lee E [ORNL; DiFazio, Stephen P [West Virginia University

    2009-01-01

    The 18S-28S rDNA and 5S rDNA loci in Populus trichocarpa were localized using fluorescent in situ hybridization (FISH). Two 18S-28S rDNA sites and one 5S rDNA site were identified and located at the ends of 3 different chromosomes. FISH signals from the Arabidopsis -type telomere repeat sequence were observed at the distal ends of each chromosome. Six BAC clones selected from 2 linkage groups based on genome sequence assembly (LG-I and LG-VI) were localized on 2 chromosomes, as expected. BACs from LG-I hybridized to the longest chromosome in the complement. All BAC positions were found to be concordant with sequence assembly positions. BAC-FISH will be useful for delineating each of the Populus trichocarpa chromosomes and improving the sequence assembly of this model angiosperm tree species.

  14. Comparative Genomic Study of the Thioredoxin Family in Photosynthetic Organisms with Emphasis on Populus trichocarpa

    Institute of Scientific and Technical Information of China (English)

    Kamel Chibani; Gunnar Wingsle; Jean-Pierre Jacquot; Eric Gelhaye; Nicolas Rouhier

    2009-01-01

    The recent genome sequencing of Populus trichocarpa and Vitis vinifera, two models of woody plants, of Sorghum bicolor, a model of monocot using C4 metabolism, and of the moss Physcomitrella patens, together with the availability of photosynthetic organism genomes allows performance of a comparative genomic study with organisms having different ways of life, reproduction modes, biological traits, and physiologies. Thioredoxins (Trxs) are small ubiq-uitous proteins involved in the reduction of disulfide bridges in a variety of target enzymes present in all sub-cellular compartments and involved in many biochemical reactions. The genes coding for these enzymes have been identified in these newly sequenced genomes and annotated. The gene content, organization and distribution were compared to other photosynthetic organisms, leading to a refined classification. This analysis revealed that higher plants and bryo-phytes have a more complex family compared to algae and cyanobacteria and to non-photosynthetic organisms, since poplar exhibits 49 genes coding for typical and atypical thioredoxins and thioredoxin reductases, namely one-third more than monocots such as Oryza sativa and S. bicolor. The higher number of Trxs in poplar is partially explained by gene duplication in the Trx m, h, and nucleoredoxin classes. Particular attention was paid to poplar genes with emphasis on Trx-like classes called Clot, thioredoxin-like, thioredoxins of the lilium type and nucleoredoxins, which were not described in depth in previous genomic studies.

  15. Genome-wide analysis and heavy metal-induced expression profiling of the HMA gene family in Populus trichocarpa

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    Dandan eLi

    2015-12-01

    Full Text Available The heavy metal ATPase (HMA family plays an important role in transition metal transport in plants. However, this gene family has not been extensively studied in Populus trichocarpa. We identified 17 HMA genes in P. trichocarpa (PtHMAs, of which PtHMA1–PtHMA4 belonged to the zinc (Zn/cobalt (Co/cadmium (Cd/lead (Pb subgroup, and PtHMA5–PtHMA8 were members of the copper (Cu/silver (Ag subgroup. Most of the genes were localized to chromosomes I and III. Gene structure, gene chromosomal location, and synteny analyses of PtHMAs indicated that tandem and segmental duplications likely contributed to the expansion and evolution of the PtHMAs. Most of the HMA genes contained abiotic stress-related cis-elements. Tissue-specific expression of PtHMA genes showed that PtHMA1 and PtHMA4 had relatively high expression levels in the leaves, whereas Cu/Ag subgroup (PtHMA5.1- PtHMA8 genes were upregulated in the roots. High concentrations of Cu, Ag, Zn, Cd, Co, Pb and Mn differentially regulated the expression of PtHMAs in various tissues. The preliminary results of the present study generated basic information on the HMA family of Populus that may serve as foundation for future functional studies.

  16. Overexpression of Populus trichocarpa CYP85A3 promotes growth and biomass production in transgenic trees.

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    Jin, Yan-Li; Tang, Ren-Jie; Wang, Hai-Hai; Jiang, Chun-Mei; Bao, Yan; Yang, Yang; Liang, Mei-Xia; Kong, Fanjing; Li, Bei; Zhang, Hong-Xia

    2017-03-04

    Brassinosteroids (BRs) are essential hormones that play crucial roles in plant growth, reproduction and response to abiotic and biotic stress. In Arabidopsis, AtCYP85A2 works as a bifunctional cytochrome P450 monooxygenase to catalyze the conversion of castasterone (CS) to brassinolide (BL), a final rate-limiting step in the BR biosynthetic pathway. Here, we report the functional characterizations of PtCYP85A3, one of the three AtCYP85A2 homologous genes from Populus trichocarpa. PtCYP85A3 shares the highest similarity with AtCYP85A2 and can rescue the retarded-growth phenotype of the Arabidopsis cyp85a2-2 and tomato d(x) mutants. Constitutive expression of PtCYP85A3, driven by the cauliflower mosaic virus 35S promoter, increased the endogenous BR levels and significantly promoted the growth and biomass production in both transgenic tomato and poplar. Compared to the wild type (WT), plant height, shoot fresh weight and fruit yield increased 50%, 56% and 43%, respectively, in transgenic tomato plants. Similarly, plant height and stem diameter increased 15% and 25%, respectively, in transgenic poplar plants. Further study revealed that overexpression of PtCYP85A3 enhanced xylem formation without affecting the composition of cellulose and lignin, as well as the cell wall thickness in transgenic poplar. Our finding suggest that PtCYP85A3 could be used as a potential candidate gene for engineering fast growing trees with improved wood production. This article is protected by copyright. All rights reserved.

  17. Effects of in vitro ozone treatment on proteolysis of purified rubisco from two hybrid poplar clones. [Populus maximowizii x trichocarpa

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    Landry, L.G.; Pell, E.J. (Pennsylvania State Univ., University Park (USA))

    1989-04-01

    Plants exposed to ozone (O{sub 3}) exhibited symptoms of premature senescence, including early decline in quantity of rubisco. O{sub 3}-induced oxidation may cause changes in protein conformation of rubisco, resulting in enhanced proteolysis. To test this hypothesis, rubisco was purified from two hybrid clones of Populus maximowizii x trichocarpa, clones 388 and 245, and treated in vitro with O{sub 3} or air. Rubisco was then challenged with bromelain, papain, chymotrypsin, carboxypeptidase A, or endoproteinase Glu-C and percent degradation measured by SDS-PAGE and densitometric scanning of the gels. Degree of rubisco sensitivity to oxidation may be related to available sulfhydryl (SH) groups on the protein. The number of SH groups in native and denatured rubisco was measured for purified rubisco of both clones by DTNB titration method. The relationship between sensitivity to proteolysis and number and availability of SH groups is discussed.

  18. Genome-wide association implicates numerous genes and pleiotropy underlying ecological trait variation in natural populations of Populus trichocarpa

    Energy Technology Data Exchange (ETDEWEB)

    McKown, Athena [University of British Columbia, Vancouver; Klapste, Jaroslav [University of British Columbia, Vancouver; Guy, Robert [University of British Columbia, Vancouver; Geraldes, Armando [University of British Columbia, Vancouver; Porth, Ilga [University of British Columbia, Vancouver; Hannemann, Jan [University of Victoria, Canada; Friedmann, Michael [University of British Columbia, Vancouver; Muchero, Wellington [ORNL; Tuskan, Gerald A [ORNL; Ehlting, Juergen [University of Victoria, Canada; Cronk, Quentin [University of British Columbia, Vancouver; El-Kassaby, Yousry [University of British Columbia, Vancouver; Mansfield, Shawn [University of British Columbia, Vancouver; Douglas, Carl [University of British Columbia, Vancouver

    2014-01-01

    To uncover the genetic basis of phenotypic trait variation, we used 448 unrelated wild accessions of black cottonwood (Populus trichocarpa Torr. & Gray) from natural populations throughout western North America. Extensive information from large-scale trait phenotyping (with spatial and temporal replications within a common garden) and genotyping (with a 34K Populus SNP array) of all accessions were used for gene discovery in a genome-wide association study (GWAS).

  19. Population genomics of Populus trichocarpa identifies signatures of selection and adaptive trait associations

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    Evans, Luke M [West Virginia University, Morgantown; Slavov, Gancho [West Virginia University, Morgantown; Rodgers-Melnick, Eli [West Virginia University, Morgantown; Martin, Joel [U.S. Department of Energy, Joint Genome Institute; Ranjan, Priya [ORNL; Muchero, Wellington [ORNL; Brunner, Amy M. [Virginia Polytechnic Institute and State University; Schackwitz, Wendy [U.S. Department of Energy, Joint Genome Institute; Gunter, Lee E [ORNL; Chen, Jay [ORNL; Tuskan, Gerald A [ORNL; Difazio, Stephen P. [West Virginia University, Morgantown

    2014-01-01

    Forest trees are dominant components of terrestrial ecosystems that have global ecological and economic importance. Despite distributions that span wide environmental gradients, many tree populations are locally adapted, and mechanisms underlying this adaptation are poorly understood. Here we use a combination of whole-genome selection scans and association analyses of 544 Populus trichocarpa trees to reveal genomic bases of adaptive variation across a wide latitudinal range. Three hundred ninety-seven genomic regions showed evidence of recent positive and/or divergent selection and enrichment for associations with adaptive traits that also displayed patterns consistent with natural selection. These regions also provide unexpected insights into the evolutionary dynamics of duplicated genes and their roles in adaptive trait variation.

  20. Dynamic DNA cytosine methylation in the Populus trichocarpa genome: tissue-level variation and relationship to gene expression

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    Vining Kelly J

    2012-01-01

    Full Text Available Abstract Background DNA cytosine methylation is an epigenetic modification that has been implicated in many biological processes. However, large-scale epigenomic studies have been applied to very few plant species, and variability in methylation among specialized tissues and its relationship to gene expression is poorly understood. Results We surveyed DNA methylation from seven distinct tissue types (vegetative bud, male inflorescence [catkin], female catkin, leaf, root, xylem, phloem in the reference tree species black cottonwood (Populus trichocarpa. Using 5-methyl-cytosine DNA immunoprecipitation followed by Illumina sequencing (MeDIP-seq, we mapped a total of 129,360,151 36- or 32-mer reads to the P. trichocarpa reference genome. We validated MeDIP-seq results by bisulfite sequencing, and compared methylation and gene expression using published microarray data. Qualitative DNA methylation differences among tissues were obvious on a chromosome scale. Methylated genes had lower expression than unmethylated genes, but genes with methylation in transcribed regions ("gene body methylation" had even lower expression than genes with promoter methylation. Promoter methylation was more frequent than gene body methylation in all tissues except male catkins. Male catkins differed in demethylation of particular transposable element categories, in level of gene body methylation, and in expression range of genes with methylated transcribed regions. Tissue-specific gene expression patterns were correlated with both gene body and promoter methylation. Conclusions We found striking differences among tissues in methylation, which were apparent at the chromosomal scale and when genes and transposable elements were examined. In contrast to other studies in plants, gene body methylation had a more repressive effect on transcription than promoter methylation.

  1. Gene Structures, Classification, and Expression Models of the DREB Transcription Factor Subfamily in Populus trichocarpa

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    Yunlin Chen

    2013-01-01

    Full Text Available We identified 75 dehydration-responsive element-binding (DREB protein genes in Populus trichocarpa. We analyzed gene structures, phylogenies, domain duplications, genome localizations, and expression profiles. The phylogenic construction suggests that the PtrDREB gene subfamily can be classified broadly into six subtypes (DREB A-1 to A-6 in Populus. The chromosomal localizations of the PtrDREB genes indicated 18 segmental duplication events involving 36 genes and six redundant PtrDREB genes were involved in tandem duplication events. There were fewer introns in the PtrDREB subfamily. The motif composition of PtrDREB was highly conserved in the same subtype. We investigated expression profiles of this gene subfamily from different tissues and/or developmental stages. Sixteen genes present in the digital expression analysis had high levels of transcript accumulation. The microarray results suggest that 18 genes were upregulated. We further examined the stress responsiveness of 15 genes by qRT-PCR. A digital northern analysis showed that the PtrDREB17, 18, and 32 genes were highly induced in leaves under cold stress, and the same expression trends were shown by qRT-PCR. Taken together, these observations may lay the foundation for future functional analyses to unravel the biological roles of Populus’ DREB genes.

  2. Populus trichocarpa cell wall chemistry and ultrastructure trait variation, genetic control and genetic correlations.

    Science.gov (United States)

    Porth, Ilga; Klápště, Jaroslav; Skyba, Oleksandr; Lai, Ben S K; Geraldes, Armando; Muchero, Wellington; Tuskan, Gerald A; Douglas, Carl J; El-Kassaby, Yousry A; Mansfield, Shawn D

    2013-02-01

    The increasing ecological and economical importance of Populus species and hybrids has stimulated research into the investigation of the natural variation of the species and the estimation of the extent of genetic control over its wood quality traits for traditional forestry activities as well as the emerging bioenergy sector. A realized kinship matrix based on informative, high-density, biallelic single nucleotide polymorphism (SNP) genetic markers was constructed to estimate trait variance components, heritabilities, and genetic and phenotypic correlations. Seventeen traits related to wood chemistry and ultrastructure were examined in 334 9-yr-old Populus trichocarpa grown in a common-garden plot representing populations spanning the latitudinal range 44° to 58.6°. In these individuals, 9342 SNPs that conformed to Hardy-Weinberg expectations were employed to assess the genomic pair-wise kinship to estimate narrow-sense heritabilities and genetic correlations among traits. The range-wide phenotypic variation in all traits was substantial and several trait heritabilities were > 0.6. In total, 61 significant genetic and phenotypic correlations and a network of highly interrelated traits were identified. The high trait variation, the evidence for moderate to high heritabilities and the identification of advantageous trait combinations of industrially important characteristics should aid in providing the foundation for the enhancement of poplar tree breeding strategies for modern industrial use.

  3. A cell wall-bound anionic peroxidase, PtrPO21, is involved in lignin polymerization in Populus trichocarpa

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chien-Yuan; Li, Quanzi; Tunlaya-Anukit, Sermsawat; Shi, Rui; Sun, Ying-Hsuan; Wang, Jack P.; Liu, Jie; Loziuk, Philip; Edmunds, Charles W.; Miller, Zachary D.; Peszlen, Ilona; Muddiman, David C.; Sederoff, Ronald R.; Chiang, Vincent L.

    2016-03-11

    Class III peroxidases are members of a large plant-specific sequence-heterogeneous protein family. Several sequence-conserved homologs have been associated with lignin polymerization in Arabidopsis thaliana, Oryza sativa, Nicotiana tabacum, Zinnia elegans, Picea abies, and Pinus sylvestris. In Populus trichocarpa, a model species for studies of wood formation, the peroxidases involved in lignin biosynthesis have not yet been identified. To do this, we retrieved sequences of all PtrPOs from Peroxibase and conducted RNA-seq to identify candidates. Transcripts from 42 PtrPOs were detected in stem differentiating xylem (SDX) and four of them are the most xylem-abundant (PtrPO12, PtrPO21, PtrPO42, and PtrPO64). PtrPO21 shows xylem-specific expression similar to that of genes encoding the monolignol biosynthetic enzymes. Using protein cleavage-isotope dilution mass spectrometry, PtrPO21 is detected only in the cell wall fraction and not in the soluble fraction. Downregulated transgenics of PtrPO21 have a lignin reduction of ~20% with subunit composition (S/G ratio) similar to wild type. The transgenics show a growth reduction and reddish color of stem wood. The modulus of elasticity (MOE) of the stems of the downregulated PtrPO21-line 8 can be reduced to ~60% of wild type. Differentially expressed gene (DEG) analysis of PtrPO21 downregulated transgenics identified a significant overexpression of PtPrx35, suggesting a compensatory effect within the peroxidase family. No significant changes in the expression of the 49 P. trichocarpa laccases (PtrLACs) were observed.

  4. The role of water channel proteins in facilitating recovery of leaf hydraulic conductance from water stress in Populus trichocarpa.

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    Joan Laur

    Full Text Available Gas exchange is constrained by the whole-plant hydraulic conductance (Kplant. Leaves account for an important fraction of Kplant and may therefore represent a major determinant of plant productivity. Leaf hydraulic conductance (Kleaf decreases with increasing water stress, which is due to xylem embolism in leaf veins and/or the properties of the extra-xylary pathway. Water flow through living tissues is facilitated and regulated by water channel proteins called aquaporins (AQPs. Here we assessed changes in the hydraulic conductance of Populus trichocarpa leaves during a dehydration-rewatering episode. While leaves were highly sensitive to drought, Kleaf recovered only 2 hours after plants were rewatered. Recovery of Kleaf was absent when excised leaves were bench-dried and subsequently xylem-perfused with a solution containing AQP inhibitors. We examined the expression patterns of 12 highly expressed AQP genes during a dehydration-rehydration episode to identify isoforms that may be involved in leaf hydraulic adjustments. Among the AQPs tested, several genes encoding tonoplast intrinsic proteins (TIPs showed large increases in expression in rehydrated leaves, suggesting that TIPs contribute to reversing drought-induced reductions in Kleaf. TIPs were localized in xylem parenchyma, consistent with a role in facilitating water exchange between xylem vessels and adjacent living cells. Dye uptake experiments suggested that reversible embolism formation in minor leaf veins contributed to the observed changes in Kleaf.

  5. Genome-wide analysis of basic leucine zipper transcription factor families in Arabidopsis thaliana, Oryza saliva and Populus trichocarpa

    Institute of Scientific and Technical Information of China (English)

    JI Qian; ZHANG Liang-sheng; WANG Yi-fei; WANG Jian

    2009-01-01

    The basic leucine zipper (bZIP) transcription factors form a large gene family that is important in pathogen defense, light and stress signaling, etc. The Completed whole genome sequences of model plants Arabidopsis (Arabidopsis thaliana), rice (Oryza saliva) and poplar (Populus trichocarpa) constitute a valuable resource for genome-wide analysis and genomic comparative analysis, as they are representatives of the two major evolutionary lineages within the angiosperms: the monocotyledons and the dicotyledons. In this study, bioinformatics analysis identified 74, 89 and 88 bZIP genes respectively in Arabidopsis, rice and poplar. Moreover, a comprehensive overview of this gene family is presented, including the gene structure, phylogeny, chromosome distribution, conserved motifs. As a result, the plant bZIPs were organized into 10 subfamilies on basis of phylogenetic relationship. Gene duplication events during the family evolution history were also investigated. And it was further concluded that chromosomal/segmental duplication might have played a key role in gene expansion of bZIP gene family.

  6. Targeted enrichment of the black cottonwood (Populus trichocarpa gene space using sequence capture

    Directory of Open Access Journals (Sweden)

    Zhou Lecong

    2012-12-01

    Full Text Available Abstract Background High-throughput re-sequencing is rapidly becoming the method of choice for studies of neutral and adaptive processes in natural populations across taxa. As re-sequencing the genome of large numbers of samples is still cost-prohibitive in many cases, methods for genome complexity reduction have been developed in attempts to capture most ecologically-relevant genetic variation. One of these approaches is sequence capture, in which oligonucleotide baits specific to genomic regions of interest are synthesized and used to retrieve and sequence those regions. Results We used sequence capture to re-sequence most predicted exons, their upstream regulatory regions, as well as numerous random genomic intervals in a panel of 48 genotypes of the angiosperm tree Populus trichocarpa (black cottonwood, or ‘poplar’. A total of 20.76Mb (5% of the poplar genome was targeted, corresponding to 173,040 baits. With 12 indexed samples run in each of four lanes on an Illumina HiSeq instrument (2x100 paired-end, 86.8% of the bait regions were on average sequenced at a depth ≥10X. Few off-target regions (>250bp away from any bait were present in the data, but on average ~80bp on either side of the baits were captured and sequenced to an acceptable depth (≥10X to call heterozygous SNPs. Nucleotide diversity estimates within and adjacent to protein-coding genes were similar to those previously reported in Populus spp., while intergenic regions had higher values consistent with a relaxation of selection. Conclusions Our results illustrate the efficiency and utility of sequence capture for re-sequencing highly heterozygous tree genomes, and suggest design considerations to optimize the use of baits in future studies.

  7. Genome-wide analysis of Aux/IAA and ARF gene families in Populus trichocarpa

    Energy Technology Data Exchange (ETDEWEB)

    Kalluri, Udaya C [ORNL; DiFazio, Stephen P [West Virginia University; Brunner, A. [Virginia Polytechnic Institute and State University (Virginia Tech); Tuskan, Gerald A [ORNL

    2007-01-01

    Auxin/Indole-3-Acetic Acid (Aux/IAA) and Auxin Response Factor (ARF) transcription factors are key regulators of auxin responses in plants. A total of 35 Aux/IAA and 39 ARF genes were identified in the Populus genome. Comparative phylogenetic analysis revealed that the subgroups PoptrARF2, 6, 9 and 16 and PoptrIAA3, 16, 27 and 29 have differentially expanded in Populus relative to Arabidopsis. Activator ARFs were found to be two fold-overrepresented in the Populus genome. PoptrIAA and PoptrARF gene families appear to have expanded due to high segmental and low tandem duplication events. Furthermore, expression studies showed that genes in the expanded PoptrIAA3 subgroup display differential expression. The gene-family analysis reported here will be useful in conducting future functional genomics studies to understand how the molecular roles of these large gene families translate into a diversity of biologically meaningful auxin effects.

  8. The genome sequence of black cottonwood (Populus trichocarpa) reveals 18 conserved cellulose synthase (CesA) genes.

    Science.gov (United States)

    Djerbi, Soraya; Lindskog, Mats; Arvestad, Lars; Sterky, Fredrik; Teeri, Tuula T

    2005-07-01

    The genome sequence of Populus trichocarpa was screened for genes encoding cellulose synthases by using full-length cDNA sequences and ESTs previously identified in the tissue specific cDNA libraries of other poplars. The data obtained revealed 18 distinct CesA gene sequences in P. trichocarpa. The identified genes were grouped in seven gene pairs, one group of three sequences and one single gene. Evidence from gene expression studies of hybrid aspen suggests that both copies of at least one pair, CesA3-1 and CesA3-2, are actively transcribed. No sequences corresponding to the gene pair, CesA6-1 and CesA6-2, were found in Arabidopsis or hybrid aspen, while one homologous gene has been identified in the rice genome and an active transcript in Populus tremuloides. A phylogenetic analysis suggests that the CesA genes previously associated with secondary cell wall synthesis originate from a single ancestor gene and group in three distinct subgroups. The newly identified copies of CesA genes in P. trichocarpa give rise to a number of new questions concerning the mechanism of cellulose synthesis in trees.

  9. Physico-Chemical Properties and Biodegradability of Genetically Modified Populus trichocarpa and Pinus taeda

    Science.gov (United States)

    Edmunds, Charles Warren

    Increasing concerns over greenhouse gas emissions and the finite supply of fossil fuels lead to the goal of utilizing lignocellulosic feedstocks for biofuels, platform chemicals, and biocomposites. Lignin is responsible for the recalcitrance of lignocellulosic biomass and is a major barrier to its deconstruction. Great progress has been made in mapping and modifying the lignin biosynthetic pathway. However, the link between the genetic modification, resulting chemical and physical properties of the wood, and how these properties influence the thermomechanical and recalcitrance to biological and chemical degradation needs further investigation. In this dissertation, the study of modified Populus trichocarpa and Pinus taeda were utilized to accomplish this goal. Thermo-mechanical properties of genetically modified P. trichocarpa with altered lignin content and/or lignin structure were measured with a series of tools including; dynamic mechanical analysis, nuclear magnetic resonance, and wet chemistry techniques. Results demonstrated lignin content and lignin structure likely influence the glass transition temperature (Tg), and that decreased lignin content and the corresponding higher proportion of cell wall carbohydrates may contribute to increased molecular mobility in the wood polymer structure. The effect of lignin biosynthetic pathway modification on biological degradation of these transgenic wood specimens was of interest. However, experimental methods for fungal treatment on small young greenhouse-grown wood specimens are not well established. Therefore, a project was undertaken to develop a method for fungal inoculation and incubation for these unique specimens. Several parameters were tested, and a fungal treatment method was identified with sufficient weight loss after decay and significant reduction in variation of weight loss between replicates compared to previous experiments by direct inoculation of wood with liquid malt extract fungal culture

  10. Structure and Expression Profile of the Phosphate Pht1 Transporter Gene Family in Mycorrhizal Populus trichocarpa1[W

    Science.gov (United States)

    Loth-Pereda, Verónica; Orsini, Elena; Courty, Pierre-Emmanuel; Lota, Frédéric; Kohler, Annegret; Diss, Loic; Blaudez, Damien; Chalot, Michel; Nehls, Uwe; Bucher, Marcel; Martin, Francis

    2011-01-01

    Gene networks involved in inorganic phosphate (Pi) acquisition and homeostasis in woody perennial species able to form mycorrhizal symbioses are poorly known. Here, we describe the features of the 12 genes coding for Pi transporters of the Pht1 family in poplar (Populus trichocarpa). Individual Pht1 transporters play distinct roles in acquiring and translocating Pi in different tissues of mycorrhizal and nonmycorrhizal poplar during different growth conditions and developmental stages. Pi starvation triggered the up-regulation of most members of the Pht1 family, especially PtPT9 and PtPT11. PtPT9 and PtPT12 showed a striking up-regulation in ectomycorrhizas and endomycorrhizas, whereas PtPT1 and PtPT11 were strongly down-regulated. PtPT10 transcripts were highly abundant in arbuscular mycorrhiza (AM) roots only. PtPT8 and PtPT10 are phylogenetically associated to the AM-inducible Pht1 subfamily I. The analysis of promoter sequences revealed conserved motifs similar to other AM-inducible orthologs in PtPT10 only. To gain more insight into gene regulatory mechanisms governing the AM symbiosis in woody plant species, the activation of the poplar PtPT10 promoter was investigated and detected in AM of potato (Solanum tuberosum) roots. These results indicated that the regulation of AM-inducible Pi transporter genes is conserved between perennial woody and herbaceous plant species. Moreover, poplar has developed an alternative Pi uptake pathway distinct from AM plants, allowing ectomycorrhizal poplar to recruit PtPT9 and PtPT12 to cope with limiting Pi concentrations in forest soils. PMID:21705655

  11. Elucidation of Xylem-Specific Transcription Factors and Absolute Quantification of Enzymes Regulating Cellulose Biosynthesis in Populus trichocarpa.

    Science.gov (United States)

    Loziuk, Philip L; Parker, Jennifer; Li, Wei; Lin, Chien-Yuan; Wang, Jack P; Li, Quanzi; Sederoff, Ronald R; Chiang, Vincent L; Muddiman, David C

    2015-10-02

    Cellulose, the main chemical polymer of wood, is the most abundant polysaccharide in nature.1 The ability to perturb the abundance and structure of cellulose microfibrils is of critical importance to the pulp and paper industry as well as for the textile, wood products, and liquid biofuels industries. Although much has been learned at the transcript level about the biosynthesis of cellulose, a quantitative understanding at the proteome level has yet to be established. The study described herein sought to identify the proteins directly involved in cellulose biosynthesis during wood formation in Populus trichocarpa along with known xylem-specific transcription factors involved in regulating these key proteins. Development of an effective discovery proteomic strategy through a combination of subcellular fractionation of stem differentiating xylem tissue (SDX) with recently optimized FASP digestion protocols, StageTip fractionation, as well as optimized instrument parameters for global proteomic analysis using the quadrupole-orbitrap mass spectrometer resulted in the deepest proteomic coverage of SDX protein from P. trichocarpa with 9,146 protein groups being identified (1% FDR). Of these, 20 cellulosic/hemicellulosic enzymes and 43 xylem-specific transcription factor groups were identified. Finally, selection of surrogate peptides led to an assay for absolute quantification of 14 cellulosic proteins in SDX of P. trichocarpa.

  12. Comparative physiology and transcriptional networks underlying the heat shock response in Populus trichocarpa, Arabidopsis thaliana and Glycine max

    Energy Technology Data Exchange (ETDEWEB)

    Weston, David [ORNL; Wullschleger, Stan D [ORNL; Yang, Xiaohan [ORNL; Karve, Abhijit A [ORNL; Gunter, Lee E [ORNL; Jawdy, Sara [ORNL; Allen, Sara M [ORNL

    2011-01-01

    The heat shock response continues to be layered with additional complexity as interactions and crosstalk among heat shock proteins (HSPs), the reactive oxygen network and hormonal signalling are discovered. However, comparative analyses exploring variation in each of these processes among species remain relatively unexplored. In controlled environment experiments, photosynthetic response curves were conducted from 22 to 42 C and indicated that temperature optimum of light-saturated photosynthesis was greater for Glycine max relative to Arabidopsis thaliana or Populus trichocarpa. Transcript profiles were taken at defined states along the temperature response curves, and inferred pathway analysis revealed species-specific variation in the abiotic stress and the minor carbohydrate raffinose/galactinol pathways. A weighted gene co-expression network approach was used to group individual genes into network modules linking biochemical measures of the antioxidant system to leaf-level photosynthesis among P. trichocarpa, G. max and A. thaliana. Network-enabled results revealed an expansion in the G. max HSP17 protein family and divergence in the regulation of the antioxidant and heat shock modules relative to P. trichocarpa and A. thaliana. These results indicate that although the heat shock response is highly conserved, there is considerable species-specific variation in its regulation.

  13. Down-regulation of glycosyltransferase 8D genes in Populus trichocarpa caused reduced mechanical strength and xylan content in wood.

    Science.gov (United States)

    Li, Quanzi; Min, Douyong; Wang, Jack Peng-Yu; Peszlen, Ilona; Horvath, Laszlo; Horvath, Balazs; Nishimura, Yufuko; Jameel, Hasan; Chang, Hou-Min; Chiang, Vincent L

    2011-02-01

    Members of glycosyltransferase protein families GT8, GT43 and GT47 are implicated in the biosynthesis of xylan in the secondary cell walls of Arabidopsis. The Arabidopsis mutant irx8 has a 60% reduction in xylan. However, over-expression of an ortholog of Arabidopsis IRX8, poplar PoGT8D, in Arabidopsis irx8 mutant could not restore xylan synthesis. The functions of tree GT8D genes remain unclear. We identified two GT8 gene homologs, PtrGT8D1 and PtrGT8D2, in Populus trichocarpa. They are the only two GT8D members and are abundantly and specifically expressed in the differentiating xylem of P. trichocarpa. PtrGT8D1 transcript abundance was >7 times that of PtrGT8D2. To elucidate the genetic function of GT8D in P. trichocarpa, the expression of PtrGT8D1 and PtrGT8D2 was simultaneously knocked down through RNAi. Four transgenic lines had 85-94% reduction in transcripts of PtrGT8D1 and PtrGT8D2, resulting in 29-36% reduction in stem wood xylan content. Xylan reduction had essentially no effect on cellulose quantity but caused an 11-25% increase in lignin. These transgenics exhibit a brittle wood phenotype, accompanied by increased vessel diameter and thinner fiber cell walls in stem xylem. Stem modulus of elasticity and modulus of rupture were reduced by 17-29% and 16-23%, respectively, and were positively correlated with xylan content but negatively correlated with lignin quantity. These results suggest that PtrGT8Ds play key roles in xylan biosynthesis in wood. Xylan may be a more important factor than lignin affecting the stiffness and fracture strength of wood.

  14. Network analysis reveals the relationship among wood properties, gene expression levels and genotypes of natural Populus trichocarpa accessions.

    Science.gov (United States)

    Porth, Ilga; Klápště, Jaroslav; Skyba, Oleksandr; Friedmann, Michael C; Hannemann, Jan; Ehlting, Juergen; El-Kassaby, Yousry A; Mansfield, Shawn D; Douglas, Carl J

    2013-11-01

    High-throughput approaches have been widely applied to elucidate the genetic underpinnings of industrially important wood properties. Wood traits are polygenic in nature, but gene hierarchies can be assessed to identify the most important gene variants controlling specific traits within complex networks defining the overall wood phenotype. We tested a large set of genetic, genomic, and phenotypic information in an integrative approach to predict wood properties in Populus trichocarpa. Nine-yr-old natural P. trichocarpa trees including accessions with high contrasts in six traits related to wood chemistry and ultrastructure were profiled for gene expression on 49k Nimblegen (Roche NimbleGen Inc., Madison, WI, USA) array elements and for 28,831 polymorphic single nucleotide polymorphisms (SNPs). Pre-selected transcripts and SNPs with high statistical dependence on phenotypic traits were used in Bayesian network learning procedures with a stepwise K2 algorithm to infer phenotype-centric networks. Transcripts were pre-selected at a much lower logarithm of Bayes factor (logBF) threshold than SNPs and were not accommodated in the networks. Using persistent variables, we constructed cross-validated networks for variability in wood attributes, which contained four to six variables with 94-100% predictive accuracy. Accommodated gene variants revealed the hierarchy in the genetic architecture that underpins substantial phenotypic variability, and represent new tools to support the maximization of response to selection.

  15. Identification of quantitative trait loci affecting ectomycorrhizal symbiosis in an interspecific F1 poplar cross and differential expression of genes in ectomycorrhizas of the two parents: Populus deltoides and Populus trichocarpa

    Energy Technology Data Exchange (ETDEWEB)

    Labbe, Jessy L [ORNL; Jorge, Veronique [INRA, Nancy, France; Vion, Patrice [INRA, Nancy, France; Marcais, Benoit [INRA, Nancy, France; Bastien, Catherine [INRA, Orleans, France; Tuskan, Gerald A [ORNL; Martin, Francis [INRA, Nancy, France; Le Tacon, F [UMR, France

    2011-01-01

    A Populus deltoides Populus trichocarpa F1 pedigree was analyzed for quantitative trait loci (QTLs) affecting ectomycorrhizal development and for microarray characterization of gene networks involved in this symbiosis. A 300 genotype progeny set was evaluated for its ability to form ectomycorrhiza with the basidiomycete Laccaria bicolor. The percentage of mycorrhizal root tips was determined on the root systems of all 300 progeny and their two parents. QTL analysis identified four significant QTLs, one on the P. deltoides and three on the P. trichocarpa genetic maps. These QTLs were aligned to the P. trichocarpa genome and each contained several megabases and encompass numerous genes. NimbleGen whole-genome microarray, using cDNA from RNA extracts of ectomycorrhizal root tips from the parental genotypes P. trichocarpa and P. deltoides, was used to narrow the candidate gene list. Among the 1,543 differentially expressed genes (p value 0.05; 5.0-fold change in transcript level) having different transcript levels in mycorrhiza of the two parents, 41 transcripts were located in the QTL intervals: 20 in Myc_d1, 14 in Myc_t1, and seven in Myc_t2, while no significant differences among transcripts were found in Myc_t3. Among these 41 transcripts, 25 were overrepresented in P. deltoides relative to P. trichocarpa; 16 were overrepresented in P. trichocarpa. The transcript showing the highest overrepresentation in P. trichocarpa mycorrhiza libraries compared to P. deltoides mycorrhiza codes for an ethylene-sensitive EREBP-4 protein which may repress defense mechanisms in P. trichocarpa while the highest overrepresented transcripts in P. deltoides code for proteins/genes typically associated with pathogen resistance.

  16. Identification of genes regulated by histone acetylation during root development in Populus trichocarpa.

    Science.gov (United States)

    Ma, Xujun; Zhang, Chao; Zhang, Bing; Yang, Chuanping; Li, Shujuan

    2016-02-04

    Histone deacetylases (HDACs) are key enzymes catalyzing the removal of acetyl groups from histones. HDACs act in concert with histone acetyltransferases (HATs) to regulate histone acetylation status, which modifies chromatin structure, affecting gene transcription and thus regulating multiple biological processes such as plant growth and development. Over a decade, certain HDACs in herbaceous plants have been deeply studied. However, functions of HDACs in woody plants are not well understood. Histone deacetylase specific inhibitor trichostatin A (TSA) was used to investigate the role of HDACs in organogenesis of roots and root development in Populus trochocarpa. The adventitious roots were regenerated and grown on medium supplemented with 0, 1, and 2.5 μM TSA. TSA treatment delayed root regeneration and inhibited primary root growth. To examine the genes modified by TSA in the regenerated roots, tag-based digital gene expression (DGE) analysis was performed using Illumina HiSeqTM 2000. Approximately 4.5 million total clean tags were mapped per library. The distinct clean tags for the three libraries corresponding to 0, 1 and 2.5 μM TSA treatment were 166167, 143103 and 153507, from which 38.45%, 31.84% and 38.88% were mapped unambiguously to the unigene database, respectively. Most of the tags were expressed at similar levels, showing a histone acetylation during root growth and development, which will lead to a better understanding of the mechanism controlling root development.

  17. Genome-wide association implicates numerous genes underlying ecological trait variation in natural populations of Populus trichocarpa.

    Science.gov (United States)

    McKown, Athena D; Klápště, Jaroslav; Guy, Robert D; Geraldes, Armando; Porth, Ilga; Hannemann, Jan; Friedmann, Michael; Muchero, Wellington; Tuskan, Gerald A; Ehlting, Jürgen; Cronk, Quentin C B; El-Kassaby, Yousry A; Mansfield, Shawn D; Douglas, Carl J

    2014-07-01

    In order to uncover the genetic basis of phenotypic trait variation, we used 448 unrelated wild accessions of black cottonwood (Populus trichocarpa) from much of its range in western North America. Extensive data from large-scale trait phenotyping (with spatial and temporal replications within a common garden) and genotyping (with a 34 K Populus single nucleotide polymorphism (SNP) array) of all accessions were used for gene discovery in a genome-wide association study (GWAS). We performed GWAS with 40 biomass, ecophysiology and phenology traits and 29,355 filtered SNPs representing 3518 genes. The association analyses were carried out using a Unified Mixed Model accounting for population structure effects among accessions. We uncovered 410 significant SNPs using a Bonferroni-corrected threshold (P<1.7×10(-6)). Markers were found across 19 chromosomes, explained 1-13% of trait variation, and implicated 275 unique genes in trait associations. Phenology had the largest number of associated genes (240 genes), followed by biomass (53 genes) and ecophysiology traits (25 genes). The GWAS results propose numerous loci for further investigation. Many traits had significant associations with multiple genes, underscoring their genetic complexity. Genes were also identified with multiple trait associations within and/or across trait categories. In some cases, traits were genetically correlated while in others they were not.

  18. In Silico Identification and Characterization of N-Terminal Acetyltransferase Genes of Poplar (Populus trichocarpa

    Directory of Open Access Journals (Sweden)

    Hang-Yong Zhu

    2014-01-01

    Full Text Available 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.

  19. A 34K SNP genotyping array for Populus trichocarpa: design, application to the study of natural populations and transferability to other Populus species

    Energy Technology Data Exchange (ETDEWEB)

    Geraldes, Armando [University of British Columbia, Vancouver; Hannemann, Jan [University of Victoria, Canada; Grassa, Chris [University of British Columbia, Vancouver; Farzaneh, Nima [University of British Columbia, Vancouver; Porth, Ilga [University of British Columbia, Vancouver; McKown, Athena [University of British Columbia, Vancouver; Skyba, Oleksandr [University of British Columbia, Vancouver; Li, Eryang [University of British Columbia, Vancouver; Mike, Fujita [University of British Columbia, Vancouver; Friedmann, Michael [University of British Columbia, Vancouver; Wasteneys, Geoffrey [University of British Columbia, Vancouver; Guy, Robert [University of British Columbia, Vancouver; El-Kassaby, Yousry [University of British Columbia, Vancouver; Mansfield, Shawn [University of British Columbia, Vancouver; Cronk, Quentin [University of British Columbia, Vancouver; Ehlting, Juergen [University of Victoria, Canada; Douglas, Carl [University of British Columbia, Vancouver; DiFazio, Stephen P [West Virginia University, Morgantown; Slavov, Gancho [West Virginia University, Morgantown; Ranjan, Priya [ORNL; Muchero, Wellington [ORNL; Gunter, Lee E [ORNL; Wymore, Ann [ORNL; Tuskan, Gerald A [ORNL; Martin, Joel [U.S. Department of Energy, Joint Genome Institute; Schackwitz, Wendy [U.S. Department of Energy, Joint Genome Institute; Pennacchio, Christa [U.S. Department of Energy, Joint Genome Institute; Rokhsar, Daniel [U.S. Department of Energy, Joint Genome Institute

    2013-01-01

    Genetic mapping of quantitative traits requires genotypic data for large numbers of markers in many individuals. Despite the declining costs of genotyping by sequencing, for most studies, the use of large SNP genotyping arrays still offers the most cost-effective solution for large-scale targeted genotyping. Here we report on the design and performance of a SNP genotyping array for Populus trichocarpa (black cottonwood). This genotyping array was designed with SNPs pre-ascertained in 34 wild accessions covering most of the species range. Due to the rapid decay of linkage disequilibrium in P. trichocarpa we adopted a candidate gene approach to the array design that resulted in the selection of 34,131 SNPs, the majority of which are located in, or within 2 kb, of 3,543 candidate genes. A subset of the SNPs (539) was selected based on patterns of variation among the SNP discovery accessions. We show that more than 95% of the loci produce high quality genotypes and that the genotyping error rate for these is likely below 2%, indicating that high-quality data are generated with this array. We demonstrate that even among small numbers of samples (n=10) from local populations over 84% of loci are polymorphic. We also tested the applicability of the array to other species in the genus and found that due to ascertainment bias the number of polymorphic loci decreases rapidly with genetic distance, with the largest numbers detected in other species in section Tacamahaca (P. balsamifera and P. angustifolia). Finally, we provide evidence for the utility of the array for intraspecific studies of genetic differentiation and for species assignment and the detection of natural hybrids.

  20. A cost-effective colorimetric assay for phenolic O-methyltransferases and characterization of caffeate 3-O-methyltranferases from Populus trichocarpa

    Energy Technology Data Exchange (ETDEWEB)

    Bhuiya, M.W.; Liu, C.

    2009-01-01

    S-Adenosyl-L-methionine (AdoMet)-dependent O-methyltransferases (OMTs) catalyze the transmethylation of a variety of phenolics in bacteria, plants, and humans. To rapidly characterize phenolic OMT activities, we adapted Gibbs reagent, the dye originally used for detecting phenols, to develop a convenient assay method for measuring the catalytic properties of enzymatic transmethylation of phenolics. We demonstrated that Gibbs reagent reacted with phenolics yielding distinct absorptive characters that we used to further develop the assay to monitor the reactivities of phenolic OMTs. To validate the method, we identified two caffeate/5-hydroxyferulate 3/5-O-methyltransferases (COMTs) from the black cottonwood, Populus trichocarpa. Together with a few other plant type I OMTs, we demonstrated that our Gibbs reagent-mediated colorimetric assay could reliably determine the functions and kinetic parameters of phenolic OMTs. Because Gibbs reagent reacting with different regioselectively modified phenolics displays different colorimetric properties, the assay method can be used to monitor both substrate specificity and the regioselectivity of phenolic OMTs.

  1. Genomic and functional approaches reveal a case of adaptive introgression from Populus balsamifera (balsam poplar) in P. trichocarpa (black cottonwood).

    Science.gov (United States)

    Suarez-Gonzalez, Adriana; Hefer, Charles A; Christe, Camille; Corea, Oliver; Lexer, Christian; Cronk, Quentin C B; Douglas, Carl J

    2016-06-01

    Natural hybrid zones in forest trees provide systems to study the transfer of adaptive genetic variation by introgression. Previous landscape genomic studies in Populus trichocarpa, a keystone tree species, indicated genomic footprints of admixture with its sister species Populus balsamifera and identified candidate genes for local adaptation. Here, we explored the patterns of introgression and signals of local adaptation in P. trichocarpa and P. balsamifera, employing genome resequencing data from three chromosomes in pure species and admixed individuals from wild populations. Local ancestry analysis in admixed P. trichocarpa revealed a telomeric region in chromosome 15 with P. balsamifera ancestry, containing several candidate genes for local adaptation. Genomic analyses revealed signals of selection in certain genes in this region (e.g. PRR5, COMT1), and functional analyses based on gene expression variation and correlations with adaptive phenotypes suggest distinct functions of the introgressed alleles. In contrast, a block of genes in chromosome 12 paralogous to the introgressed region showed no signs of introgression or signatures of selection. We hypothesize that the introgressed region in chromosome 15 has introduced modular or cassette-like variation into P. trichocarpa. These linked adaptive mutations are associated with a block of genes in chromosome 15 that appear to have undergone neo- or subfunctionalization relative to paralogs in a duplicated region on chromosome 12 that show no signatures of adaptive variation. The association between P. balsamifera introgressed alleles with the expression of adaptive traits in P. trichocarpa supports the hypothesis that this is a case of adaptive introgression in an ecologically important foundation species.

  2. Association genetics, geography and ecophysiology link stomatal patterning in Populus trichocarpa with carbon gain and disease resistance trade-offs.

    Science.gov (United States)

    McKown, Athena D; Guy, Robert D; Quamme, Linda; Klápště, Jaroslav; La Mantia, Jonathan; Constabel, C P; El-Kassaby, Yousry A; Hamelin, Richard C; Zifkin, Michael; Azam, M S

    2014-12-01

    Stomata are essential for diffusive entry of gases to support photosynthesis, but may also expose internal leaf tissues to pathogens. To uncover trade-offs in range-wide adaptation relating to stomata, we investigated the underlying genetics of stomatal traits and linked variability in these traits with geoclimate, ecophysiology, condensed foliar tannins and pathogen susceptibility in black cottonwood (Populus trichocarpa). Upper (adaxial) and lower (abaxial) leaf stomatal traits were measured from 454 accessions collected throughout much of the species range. We calculated broad-sense heritability (H(2) ) of stomatal traits and, using SNP data from a 34K Populus SNP array, performed a genome-wide association studies (GWAS) to uncover genes underlying stomatal trait variation. H(2) values for stomatal traits were moderate (average H(2) = 0.33). GWAS identified genes associated primarily with adaxial stomata, including polarity genes (PHABULOSA), stomatal development genes (BRASSINOSTEROID-INSENSITIVE 2) and disease/wound-response genes (GLUTAMATE-CYSTEINE LIGASE). Stomatal traits correlated with latitude, gas exchange, condensed tannins and leaf rust (Melampsora) infection. Latitudinal trends of greater adaxial stomata numbers and guard cell pore size corresponded with higher stomatal conductance (gs ) and photosynthesis (Amax ), faster shoot elongation, lower foliar tannins and greater Melampsora susceptibility. This suggests an evolutionary trade-off related to differing selection pressures across the species range. In northern environments, more adaxial stomata and larger pore sizes reflect selection for rapid carbon gain and growth. By contrast, southern genotypes have fewer adaxial stomata, smaller pore sizes and higher levels of condensed tannins, possibly linked to greater pressure from natural leaf pathogens, which are less significant in northern ecosystems.

  3. Leaf wax n-alkane δD values are determined early in the ontogeny of Populus trichocarpa leaves when grown under controlled environmental conditions.

    Science.gov (United States)

    Kahmen, Ansgar; Dawson, Todd E; Vieth, Andrea; Sachse, Dirk

    2011-10-01

    The stable hydrogen isotope ratios (δD) of leaf wax n-alkanes record valuable information on plant and ecosystem water relations. It remains, however, unknown if leaf wax n-alkane δD values record only environmental variation during the brief period of time of leaf growth or if leaf wax n-alkane δD values are affected by environmental variability throughout the entire lifespan of a leaf. To resolve these uncertainties, we irrigated Populus trichocarpa trees with a pulse of deuterium-enriched water and used compound-specific stable hydrogen isotope analyses to test if the applied tracer could be recovered from leaf wax n-alkanes of leaves that were at different stages of their development during the tracer application. Our experiment revealed that only leaf wax n-alkanes from leaves that had developed during the time of the tracer application were affected, while leaves that were already fully matured at the time of the tracer application were not. We conclude from our study that under controlled environmental conditions, leaf wax n-alkanes are synthesized only early in the ontogeny of a leaf. Our experiment has implications for the interpretation of leaf wax n-alkane δD values in an environmental context, as it suggests that these compounds record only a brief period of the environmental variability that a leaf experiences throughout its life.

  4. A 34K SNP genotyping array for Populus trichocarpa: design, application to the study of natural populations and transferability to other Populus species.

    Science.gov (United States)

    Geraldes, A; Difazio, S P; Slavov, G T; Ranjan, P; Muchero, W; Hannemann, J; Gunter, L E; Wymore, A M; Grassa, C J; Farzaneh, N; Porth, I; McKown, A D; Skyba, O; Li, E; Fujita, M; Klápště, J; Martin, J; Schackwitz, W; Pennacchio, C; Rokhsar, D; Friedmann, M C; Wasteneys, G O; Guy, R D; El-Kassaby, Y A; Mansfield, S D; Cronk, Q C B; Ehlting, J; Douglas, C J; Tuskan, G A

    2013-03-01

    Genetic mapping of quantitative traits requires genotypic data for large numbers of markers in many individuals. For such studies, the use of large single nucleotide polymorphism (SNP) genotyping arrays still offers the most cost-effective solution. Herein we report on the design and performance of a SNP genotyping array for Populus trichocarpa (black cottonwood). This genotyping array was designed with SNPs pre-ascertained in 34 wild accessions covering most of the species latitudinal range. We adopted a candidate gene approach to the array design that resulted in the selection of 34 131 SNPs, the majority of which are located in, or within 2 kb of, 3543 candidate genes. A subset of the SNPs on the array (539) was selected based on patterns of variation among the SNP discovery accessions. We show that more than 95% of the loci produce high quality genotypes and that the genotyping error rate for these is likely below 2%. We demonstrate that even among small numbers of samples (n = 10) from local populations over 84% of loci are polymorphic. We also tested the applicability of the array to other species in the genus and found that the number of polymorphic loci decreases rapidly with genetic distance, with the largest numbers detected in other species in section Tacamahaca. Finally, we provide evidence for the utility of the array to address evolutionary questions such as intraspecific studies of genetic differentiation, species assignment and the detection of natural hybrids.

  5. Assessment of Populus wood chemistry following the introduction of a Bt toxin gene

    Energy Technology Data Exchange (ETDEWEB)

    Tschaplinski, Timothy J [ORNL; Davis, M F [National Energy Renewable Laboratory; Tuskan, Gerald A [ORNL; Payne, M M [Boise Cascade LLC; Meilan, R [Purdue University

    2006-01-01

    Unintended changes in plant physiology, anatomy and metabolism as a result of genetic engineering are a concern as more transgenic plants are commercially deployed in the ecosystem. We compared the cell wall chemical composition of three Populus lines (Populus trichocarpa Torr. & A. Gray x Populus trichocarpa Bartr. ex Marsh., Populus trichocarpa x Populus nigra L. and Populus deltoides x Populus nigra) genetically modified to express the Cry3A or Cry3B2 protein of Bacillus thuringiensis (Bt) with the cell wall chemistry of non-transformed isogenic control lines. Three genetically modified clones, each represented by 10 independent transgenic lines, were analyzed by pyrolysis molecular beam mass spectrometry, gas chromatography/mass spectrometry and traditional wet chemical analytical methods to assess changes in cell wall composition. Based on the outcome of these techniques, there were no comprehensive differences in chemical composition between the transgenic and control lines for any of the studied clones.

  6. Evaluation of a novel promoter from Populus trichocarpa for mature xylem tissue specific gene delivery.

    Science.gov (United States)

    Nguyen, Van Phap; Cho, Jin-Seong; Choi, Young-Im; Lee, Sang-Won; Han, Kyung-Hwan; Ko, Jae-Heung

    2016-07-01

    Wood (i.e., secondary xylem) is an important raw material for many industrial applications. Mature xylem (MX) tissue-specific genetic modification offers an effective means to improve the chemical and physical properties of the wood. Here, we describe a promoter that drives strong gene expression in a MX tissue-specific manner. Using whole-transcriptome genechip analyses of different tissue types of poplar, we identified five candidate genes that had strong expression in the MX tissue. The putative promoter sequences of the five MX-specific genes were evaluated for their promoter activity in both transgenic Arabidopsis and poplar. Among them, we found the promoter of Potri.013G007900.1 (called the PtrMX3 promoter) had the strongest activity in MX and thus was further characterized. In the stem and root tissues of transgenic Arabidopsis plants, the PtrMX3 promoter activity was found exclusively in MX tissue. MX-specific activity of the promoter was reproduced in the stem tissue of transgenic poplar plants. The PtrMX3 promoter activity was not influenced by abiotic stresses or exogenously applied growth regulators, indicating the PtrMX3 promoter is bona fide MX tissue-specific. Our study provides a strong MX-specific promoter for MX-specific modifications of woody biomass.

  7. Overexpression of PtrMYB119, a R2R3-MYB transcription factor from Populus trichocarpa, promotes anthocyanin production in hybrid poplar.

    Science.gov (United States)

    Cho, Jin-Seong; Nguyen, Van Phap; Jeon, Hyung-Woo; Kim, Min-Ha; Eom, Seok Hyun; Lim, You Jin; Kim, Won-Chan; Park, Eung-Jun; Choi, Young-Im; Ko, Jae-Heung

    2016-09-01

    Anthocyanins are a group of colorful and bioactive natural pigments with important physiological and ecological functions in plants. We found an MYB transcription factor (PtrMYB119) from Populus trichocarpa that positively regulates anthocyanin production when expressed under the control of the CaMV 35S promoter in transgenic Arabidopsis Amino acid sequence analysis revealed that PtrMYB119 is highly homologous to Arabidopsis PAP1 (PRODUCTION OF ANTHOCYANIN PIGMENT1), a well-known transcriptional activator of anthocyanin biosynthesis. Independently produced transgenic poplars overexpressing PtrMYB119 or PtrMYB120 (a paralogous gene to PtrMYB119) (i.e., 35S::PtrMYB119 and 35S::PtrMYB120, respectively) showed elevated accumulation of anthocyanins in the whole plants, including leaf, stem and even root tissues. Using a reverse-phase high-performance liquid chromatography, we confirmed that the majority of the accumulated anthocyanin in our transgenic poplar is cyanidin-3-O-glucoside. Gene expression analyses revealed that most of the genes involved in the anthocyanin biosynthetic pathway were highly upregulated in 35S::PtrMYB119 poplars compared with the nontransformed control poplar. Among these genes, expression of PtrCHS1 (Chalcone Synthase1) and PtrANS2 (Anthocyanin Synthase2), which catalyze the initial and last steps of anthocyanin biosynthesis, respectively, was upregulated by up to 350-fold. Subsequent transient activation assays confirmed that PtrMYB119 activated the transcription of both PtrCHS1 and PtrANS2 Interestingly, expression of MYB182, a repressor of both anthocyanin and proanthocyanidin (PA) biosynthesis, was largely suppressed in 35S::PtrMYB119 poplars, while expression of MYB134, an activator of PA biosynthesis, was not changed significantly. More interestingly, high-level accumulation of anthocyanins in 35S::PtrMYB119 poplars did not have an adverse effect on plant growth. Taken together, our results demonstrate that PtrMYB119 and PtrMYB120

  8. 杨树环化酶基因组织表达模式和蛋白定位%Gene Expression Pattern and Subcellular Localization of Populus Trichocarpa Cyclase

    Institute of Scientific and Technical Information of China (English)

    贾志刚; 夏德安; 李淑娟

    2016-01-01

    Semi-quantitative RT-PCR analysis showed thatPotri.006G237100 gene transcripts are very low in cambium, young leaf and apical bud ofPopulus trichocarpa, but high in xylem, petiole and root. Also, high abundance ofPotri.006G237100 gene transcripts was detected in lignifying stems. These data suggest thatPotri.006G237100 gene is speciifcally and abundantly expressed in the lignifying tissues ofP. trichocarpa. In addition, the DNA fragement ofPotri.006G237100gene was constructed into plant expression vector pGWB5 and transformed into Arabidopsis plant. Five transgenic plants were attained through molecular identiifcation. Confocal laser scanning microscope analysis suggested that Potri.006G237100-GFP fusion protein is located in the cytoplasm of transgenic plants.%半定量RT-PCR显示,毛果杨形成层、幼叶和顶芽中的Potri.006G237100转录产物极低,但在木质部、叶柄和根中其转录水平却较髙,在木质化茎节其转录产物也呈现高丰度积累,这表明Potri.006G237100在毛果杨木质化组织中特异地、高丰度转录表达。实验构建pGWB5-Potri.006G237100载体,转化拟南芥、分子鉴定得到5个过量表达转基因植株,激光共聚焦分析显示融合蛋白Potri.006G237100-GFP定位在转基因植株的细胞质。

  9. Systems biology of lignin biosynthesis in Populus trichocarpa: heteromeric 4-coumaric acid:coenzyme A ligase protein complex formation, regulation, and numerical modeling.

    Science.gov (United States)

    Chen, Hsi-Chuan; Song, Jina; Wang, Jack P; Lin, Ying-Chung; Ducoste, Joel; Shuford, Christopher M; Liu, Jie; Li, Quanzi; Shi, Rui; Nepomuceno, Angelito; Isik, Fikret; Muddiman, David C; Williams, Cranos; Sederoff, Ronald R; Chiang, Vincent L

    2014-03-01

    As a step toward predictive modeling of flux through the pathway of monolignol biosynthesis in stem differentiating xylem of Populus trichocarpa, we discovered that the two 4-coumaric acid:CoA ligase (4CL) isoforms, 4CL3 and 4CL5, interact in vivo and in vitro to form a heterotetrameric protein complex. This conclusion is based on laser microdissection, coimmunoprecipitation, chemical cross-linking, bimolecular fluorescence complementation, and mass spectrometry. The tetramer is composed of three subunits of 4CL3 and one of 4CL5. 4CL5 appears to have a regulatory role. This protein-protein interaction affects the direction and rate of metabolic flux for monolignol biosynthesis in P. trichocarpa. A mathematical model was developed for the behavior of 4CL3 and 4CL5 individually and in mixtures that form the enzyme complex. The model incorporates effects of mixtures of multiple hydroxycinnamic acid substrates, competitive inhibition, uncompetitive inhibition, and self-inhibition, along with characteristic of the substrates, the enzyme isoforms, and the tetrameric complex. Kinetic analysis of different ratios of the enzyme isoforms shows both inhibition and activation components, which are explained by the mathematical model and provide insight into the regulation of metabolic flux for monolignol biosynthesis by protein complex formation.

  10. Assessment of Populus Wood Chemistry Following the Introduction of a Bt Toxin Gene

    Energy Technology Data Exchange (ETDEWEB)

    Davis, M. F.; Tuskan, G. A.; Payne, P.; Tschaplinski, T. J.; Meilan, R.

    2006-01-01

    Unintended changes in plant physiology, anatomy and metabolism as a result of genetic engineering are a concern as more transgenic plants are commercially deployed in the ecosystem. We compared the cell wall chemical composition of three Populus lines (Populus trichocarpa Torr. and A. Gray x Populus deltoides Bartr. ex Marsh., Populus trichocarpa x Populus nigra L. and Populus deltoides x Populus nigra) genetically modified to express the Cry3A or Cry3B2 protein of Bacillus thuringiensis (Bt) with the cellwall chemistry of non-transformed isogenic control lines. Three genetically modified clones, each represented by 10 independent transgenic lines, were analyzed by pyrolysis molecular beam mass spectrometry, gas chromatography/mass spectrometry and traditional wet chemical analytical methods to assess changes in cell wall composition. Based on the outcome of these techniques, there were no comprehensive differences in chemical composition between the transgenic and control lines for any of the studied clones.

  11. Transcriptome profiles of hybrid poplar (Populus trichocarpa × deltoides) reveal rapid changes in undamaged, systemic sink leaves after simulated feeding by forest tent caterpillar (Malacosoma disstria).

    Science.gov (United States)

    Philippe, Ryan N; Ralph, Steven G; Mansfield, Shawn D; Bohlmann, Jörg

    2010-11-01

    • Poplar has been established as a model tree system for genomic research of the response to biotic stresses. This study describes a series of induced transcriptome changes and the associated physiological characterization of local and systemic responses in hybrid poplar (Populus trichocarpa × deltoides) after simulated herbivory. • Responses were measured in local source (LSo), systemic source (SSo), and systemic sink (SSi) leaves following application of forest tent caterpillar (Malacosoma disstria) oral secretions to mechanically wounded leaves. • Transcriptome analyses identified spatially and temporally dynamic, distinct patterns of local and systemic gene expression in LSo, SSo and SSi leaves. Galactinol synthase was strongly and rapidly upregulated in SSi leaves. Genome analyses and full-length cDNA cloning established an inventory of poplar galactinol synthases. Induced changes of galactinol and raffinose oligosaccharides were detected by anion-exchange high-pressure liquid chromatography. • The LSo leaves showed a rapid and strong transcriptome response compared with a weaker and slower response in adjacent SSo leaves. Surprisingly, the transcriptome response in distant, juvenile SSi leaves was faster and stronger than that observed in SSo leaves. Systemic transcriptome changes of SSi leaves have signatures of rapid change of metabolism and signaling, followed by later induction of defense genes.

  12. Partitioning of Multivariate Phenotypes using Regression Trees Reveals Complex Patterns of Adaptation to Climate across the Range of Black Cottonwood (Populus trichocarpa

    Directory of Open Access Journals (Sweden)

    Regis Wendpouire Oubida

    2015-03-01

    Full Text Available Local adaptation to climate in temperate forest trees involves the integration of multiple physiological, morphological, and phenological traits. Latitudinal clines are frequently observed for these traits, but environmental constraints also track longitude and altitude. We combined extensive phenotyping of 12 candidate adaptive traits, multivariate regression trees, quantitative genetics, and a genome-wide panel of SNP markers to better understand the interplay among geography, climate, and adaptation to abiotic factors in Populus trichocarpa. Heritabilities were low to moderate (0.13 to 0.32 and population differentiation for many traits exceeded the 99th percentile of the genome-wide distribution of FST, suggesting local adaptation. When climate variables were taken as predictors and the 12 traits as response variables in a multivariate regression tree analysis, evapotranspiration (Eref explained the most variation, with subsequent splits related to mean temperature of the warmest month, frost-free period (FFP, and mean annual precipitation (MAP. These grouping matched relatively well the splits using geographic variables as predictors: the northernmost groups (short FFP and low Eref had the lowest growth, and lowest cold injury index; the southern British Columbia group (low Eref and intermediate temperatures had average growth and cold injury index; the group from the coast of California and Oregon (high Eref and FFP had the highest growth performance and the highest cold injury index; and the southernmost, high-altitude group (with high Eref and low FFP performed poorly, had high cold injury index, and lower water use efficiency. Taken together, these results suggest variation in both temperature and water availability across the range shape multivariate adaptive traits in poplar.

  13. Increasing the productivity of short-rotation Populus plantations. Final report

    Energy Technology Data Exchange (ETDEWEB)

    DeBell, D.S.; Harrington, C.A.; Clendenen, G.W.; Radwan, M.A.; Zasada, J.C. [Forest Service, Olympia, WA (United States). Pacific Northwest Research Station

    1997-12-31

    This final report represents the culmination of eight years of biological research devoted to increasing the productivity of short rotation plantations of Populus trichocarpa and Populus hybrids in the Pacific Northwest. Studies provide an understanding of tree growth, stand development and biomass yield at various spacings, and how patterns differ by Populus clone in monoclonal and polyclonal plantings. Also included is some information about factors related to wind damage in Populus plantings, use of leaf size as a predictor of growth potential, and approaches for estimating tree and stand biomass and biomass growth. Seven research papers are included which provide detailed methods, results, and interpretations on these topics.

  14. Comparative analysis of the transcriptomes of Populus

    Energy Technology Data Exchange (ETDEWEB)

    Tuskan, Gerald A [ORNL; Davis, John M [University of Florida

    2008-01-01

    Sequencing of the Populus trichocarpa genome creates an opportunity to describe the transcriptome of a woody perennial species and establish an atlas of gene expression. A comparison with the transcriptomes of other species can also define genes that are conserved or diverging in plant species. Here, the transcriptome in vegetative organs of the P. trichocarpa reference genotype Nisqually-1 was characterized. A comparison with Arabidopsis thaliana orthologs was used to distinguish gene functional categories that may be evolving differently in a woody perennial and an annual herbaceous species. A core set of genes expressed in common among vegetative organs was detected, as well as organ-specific genes. Statistical tests identified chromatin domains, where adjacent genes were expressed more frequently than expected by chance. Extensive divergence was detected in the expression patterns of A. thaliana and P. trichocarpa orthologs, but transcription of a small number of genes appeared to have remained conserved in the two species. Despite separation of lineages for over 100 million yr, these results suggest that selection has limited transcriptional divergence of genes associated with some essential functions in A. thaliana and P. trichocarpa. However, extensive remodeling of transcriptional networks indicates that expression regulation may be a key determinant of plant diversity.

  15. Identification and Characterization of the Populus AREB/ABF Subfamily

    Institute of Scientific and Technical Information of China (English)

    Lexiang Ji; Jia Wang; Meixia Ye; Ying Li; Bin Guo; Zhong Chen; Hao Li; Xinmin An

    2013-01-01

    Abscisic acid (ABA) is a major plant hormone that plays an important role in responses to abiotic stresses.The ABA-responsive element binding proteinlABRE-binding factor (AREB/ABF) gene subfamily contains crucial transcription factors in the ABA-mediated signaling pathway.In this study,a total of 14 putative AREB/ABF members were identified in the Populus trichocarpa Torr.& Gray.genome using five AREB/ABF amino acid sequences from Arabidopsis thaliana L.as probes.The 14 putative Populus subfamily members showed high protein similarities,especially in the basic leucine zipper (bZlP) domain region.A neighbor-joining analysis combined with gene structure data revealed homology among the 14 genes.The expression patterns of the Populus AREB/ABF subfamily suggested that the most abundant transcripts of 11 genes occurred in leaf tissues,while two genes were most transcribed in root tissues.Significantly,eight Populus AREB/ABF gene members were upregulated after treatment with 100 μM exogenous ABA,while the other six members were downregulated.We identified the expression profiles of the subfamily members in Populus tissues and elucidated different response patterns of Populus AREB/ABF members to ABA stress.This study provided insight into the roles of Populus AREB/ABF homologues in plant response to abiotic stresses.

  16. Characterization of MORE AXILLARY GROWTH genes in Populus.

    Directory of Open Access Journals (Sweden)

    Olaf Czarnecki

    Full Text Available Strigolactones are a new class of plant hormones that play a key role in regulating shoot branching. Studies of branching mutants in Arabidopsis, pea, rice and petunia have identified several key genes involved in strigolactone biosynthesis or signaling pathway. In the model plant Arabidopsis, MORE AXILLARY GROWTH1 (MAX1, MAX2, MAX3 and MAX4 are four founding members of strigolactone pathway genes. However, little is known about the strigolactone pathway genes in the woody perennial plants.Here we report the identification of MAX homologues in the woody model plant Populus trichocarpa. We identified the sequence homologues for each MAX protein in P. trichocarpa. Gene expression analysis revealed that Populus MAX paralogous genes are differentially expressed across various tissues and organs. Furthermore, we showed that Populus MAX genes could complement or partially complement the shoot branching phenotypes of the corresponding Arabidopsis max mutants.This study provides genetic evidence that strigolactone pathway genes are likely conserved in the woody perennial plants and lays a foundation for further characterization of strigolactone pathway and its functions in the woody perennial plants.

  17. Protease gene families in Populus and Arabidopsis

    Directory of Open Access Journals (Sweden)

    Jansson Stefan

    2006-12-01

    Full Text Available Abstract Background Proteases play key roles in plants, maintaining strict protein quality control and degrading specific sets of proteins in response to diverse environmental and developmental stimuli. Similarities and differences between the proteases expressed in different species may give valuable insights into their physiological roles and evolution. Results We have performed a comparative analysis of protease genes in the two sequenced dicot genomes, Arabidopsis thaliana and Populus trichocarpa by using genes coding for proteases in the MEROPS database 1 for Arabidopsis to identify homologous sequences in Populus. A multigene-based phylogenetic analysis was performed. Most protease families were found to be larger in Populus than in Arabidopsis, reflecting recent genome duplication. Detailed studies on e.g. the DegP, Clp, FtsH, Lon, rhomboid and papain-Like protease families showed the pattern of gene family expansion and gene loss was complex. We finally show that different Populus tissues express unique suites of protease genes and that the mRNA levels of different classes of proteases change along a developmental gradient. Conclusion Recent gene family expansion and contractions have made the Arabidopsis and Populus complements of proteases different and this, together with expression patterns, gives indications about the roles of the individual gene products or groups of proteases.

  18. Bioinformatics Analysis of 4-hydroxy-3-methyl-2- buten1yl diphosphate synthase (HDS) in Populus trichocarpa%毛果杨1-羟基-2-甲基-2-(E)-丁烯基-4-二磷酸合酶(HDS)基因的生物信息学分析

    Institute of Scientific and Technical Information of China (English)

    刘立辉; 李成浩; 杨静莉; 夏德安

    2012-01-01

    [目的]研究HDS基因间的同源性及其进化关系.[方法]以毛果杨的HDS基因为研究对象,利用生物信息学软件及网站对其进行碱基分布、氨基酸组成、亲疏水性、保守区以及二级结构和三级结构的预测与分析.,并与其他10个物种的HDS基因序列进行多重比对与进化分析.[结果]毛果杨HDS基因的单链mRNA序列长1 956 bp,编码由656个氨基酸组成的蛋白质,该蛋白质相对分子质量为72 937.03,其中含量最高的是Leu,为10.50%;整个多肽中疏水性氨基酸只占39.63%,有10个亲水区和6个疏水区;与其他10个物种同源性多重比对发现同源性最高达99%.[结论]毛果杨HDS基因处于稳定状态,编码的蛋白为亲水性蛋白,在进化过程中是保守的;试验中获得的保守区段序列信息为新基因的克隆奠定了基础.%[ Objective] The aim was to study the homology and evolutionary relationship among HAD genes. [ Method] Based on HDS gene of Populus trichocarpa, bioinformatics software and website were used to predict and analyze base distribution, amino acids composition, hydrophil-city or hydrophobicity, hyperconservative region, secondary structure, and three-level structure. The results were used to compare with HDS gene sequences of other ten species and related evolution analysis was followed. [ Result ] mRNA, single chain of HDS gene of Populus trichocarpa , was 1 956 bp in length, code was made up of proteins containing amino acids of 656, and relative molecular mass of protein was 72 937.03 with Leu of 10. 50% involume; in polypeptide, hydrophobic amino acid was only of 39.63% with hydrophilc region of 10 and hy-drophobic region of 6; after many comparisons with other ten species, homology was found as high as 99%. [ Conclusion ] HDS gene of Populus trichocarpa was quite stable and coded albumen was hydrophilic protein which was quite conservative in evolution; sequence information in conservative region gained in the

  19. Elucidating the evolutionary history and expression patterns of nucleoside phosphorylase paralogs (vegetative storage proteins) in Populus and the plant kingdom.

    Science.gov (United States)

    Pettengill, Emily A; Pettengill, James B; Coleman, Gary D

    2013-08-19

    Nucleoside phosphorylases (NPs) have been extensively investigated in human and bacterial systems for their role in metabolic nucleotide salvaging and links to oncogenesis. In plants, NP-like proteins have not been comprehensively studied, likely because there is no evidence of a metabolic function in nucleoside salvage. However, in the forest trees genus Populus a family of NP-like proteins function as an important ecophysiological adaptation for inter- and intra-seasonal nitrogen storage and cycling. We conducted phylogenetic analyses to determine the distribution and evolution of NP-like proteins in plants. These analyses revealed two major clusters of NP-like proteins in plants. Group I proteins were encoded by genes across a wide range of plant taxa while proteins encoded by Group II genes were dominated by species belonging to the order Malpighiales and included the Populus Bark Storage Protein (BSP) and WIN4-like proteins. Additionally, we evaluated the NP-like genes in Populus by examining the transcript abundance of the 13 NP-like genes found in the Populus genome in various tissues of plants exposed to long-day (LD) and short-day (SD) photoperiods. We found that all 13 of the Populus NP-like genes belonging to either Group I or II are expressed in various tissues in both LD and SD conditions. Tests of natural selection and expression evolution analysis of the Populus genes suggests that divergence in gene expression may have occurred recently during the evolution of Populus, which supports the adaptive maintenance models. Lastly, in silico analysis of cis-regulatory elements in the promoters of the 13 NP-like genes in Populus revealed common regulatory elements known to be involved in light regulation, stress/pathogenesis and phytohormone responses. In Populus, the evolution of the NP-like protein and gene family has been shaped by duplication events and natural selection. Expression data suggest that previously uncharacterized NP-like proteins may

  20. Effects of Planting Density on Growth of New Clones in Populus tomentosa

    Institute of Scientific and Technical Information of China (English)

    Zhang Zihui; Zhang Zhiyi; Lin Shanzhi; Li Xinguo

    2003-01-01

    Effects of seven planting densities on the growth and tree form of nine 5-year-old new clones in Populus tomentosa were studied. The plantations, arranged with completely random block design, were located in Wuzhi County, Henan Province. Results indicated that effects of planting density on the diameter at breast height (DBH), individual volume and growing stock increment of all new clones in P. tomentosa were significant at the 1% level of probability, effects of planting density on the tree height increment of new clones B2 and B31 and on the live branches height (LBH) increment of new clones B5 and B30 were significant at the 5% level of probability, while the interaction between planting density and clone was not significant at the 5% level of probability. It was concluded that the degree of differences among new clones within the same planting density was different with different planting densities and traits. For short rotation industrial timber, clones B1, B3, B4, B5, B7, B9, B31 were suitable with the density of 1 000-2 500 trees per hectare, while for bigger diameter timber, clones B1, B3, B4, B7, B9, B31 could be used with the planting density of 660-833 trees per hectare. Clonal repeatability was also different in different planting densities.

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

    Science.gov (United States)

    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 boreal plant species.

  2. Variable Nitrogen Fixation in Wild Populus.

    Directory of Open Access Journals (Sweden)

    Sharon L Doty

    Full Text Available The microbiome of plants is diverse, and like that of animals, is important for overall health and nutrient acquisition. In legumes and actinorhizal plants, a portion of essential nitrogen (N is obtained through symbiosis with nodule-inhabiting, N2-fixing microorganisms. However, a variety of non-nodulating plant species can also thrive in natural, low-N settings. Some of these species may rely on endophytes, microorganisms that live within plants, to fix N2 gas into usable forms. Here we report the first direct evidence of N2 fixation in the early successional wild tree, Populus trichocarpa, a non-leguminous tree, from its native riparian habitat. In order to measure N2 fixation, surface-sterilized cuttings of wild poplar were assayed using both 15N2 incorporation and the commonly used acetylene reduction assay. The 15N label was incorporated at high levels in a subset of cuttings, suggesting a high level of N-fixation. Similarly, acetylene was reduced to ethylene in some samples. The microbiota of the cuttings was highly variable, both in numbers of cultured bacteria and in genetic diversity. Our results indicated that associative N2-fixation occurred within wild poplar and that a non-uniformity in the distribution of endophytic bacteria may explain the variability in N-fixation activity. These results point to the need for molecular studies to decipher the required microbial consortia and conditions for effective endophytic N2-fixation in trees.

  3. Epigenomics of Development in Populus

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, Steve; Freitag, Michael; Mockler, Todd

    2013-01-10

    We conducted research to determine the role of epigenetic modifications during tree development using poplar (Populus trichocarpa), a model woody feedstock species. Using methylated DNA immunoprecipitation (MeDIP) or chromatin immunoprecipitation (ChIP), followed by high-throughput sequencing, we are analyzed DNA and histone methylation patterns in the P. trichocarpa genome in relation to four biological processes: bud dormancy and release, mature organ maintenance, in vitro organogenesis, and methylation suppression. Our project is now completed. We have 1) produced 22 transgenic events for a gene involved in DNA methylation suppression and studied its phenotypic consequences; 2) completed sequencing of methylated DNA from eleven target tissues in wildtype P. trichocarpa; 3) updated our customized poplar genome browser using the open-source software tools (2.13) and (V2.2) of the P. trichocarpa genome; 4) produced summary data for genome methylation in P. trichocarpa, including distribution of methylation across chromosomes and in and around genes; 5) employed bioinformatic and statistical methods to analyze differences in methylation patterns among tissue types; and 6) used bisulfite sequencing of selected target genes to confirm bioinformatics and sequencing results, and gain a higher-resolution view of methylation at selected genes 7) compared methylation patterns to expression using available microarray data. Our main findings of biological significance are the identification of extensive regions of the genome that display developmental variation in DNA methylation; highly distinctive gene-associated methylation profiles in reproductive tissues, particularly male catkins; a strong whole genome/all tissue inverse association of methylation at gene bodies and promoters with gene expression; a lack of evidence that tissue specificity of gene expression is associated with gene methylation; and evidence that genome methylation is a significant impediment to tissue

  4. Inositol Hexakis Phosphate is the Seasonal Phosphorus Reservoir in the Deciduous Woody Plant Populus alba L.

    Science.gov (United States)

    Kurita, Yuko; Baba, Kei'ichi; Ohnishi, Miwa; Matsubara, Ryosuke; Kosuge, Keiko; Anegawa, Aya; Shichijo, Chizuko; Ishizaki, Kimitsune; Kaneko, Yasuko; Hayashi, Masahiko; Suzaki, Toshinobu; Fukaki, Hidehiro; Mimura, Tetsuro

    2017-09-01

    Seasonal recycling of nutrients is an important strategy for deciduous perennials. Deciduous perennials maintain and expand their nutrient pools by the autumn nutrient remobilization and the subsequent winter storage throughout their long life. Phosphorus (P), one of the most important elements in living organisms, is remobilized from senescing leaves during autumn in deciduous trees. However, it remains unknown how phosphate is stored over winter. Here we show that in poplar trees (Populus alba L.), organic phosphates are accumulated in twigs from late summer to winter, and that IP6 (myo-inositol-1,2,3,4,5,6-hexakis phosphate: phytic acid) is the primary storage form. IP6 was found in high concentrations in twigs during winter and quickly decreased in early spring. In parenchyma cells of winter twigs, P was associated with electron-dense structures, similar to globoids found in seeds of higher plants. Various other deciduous trees were also found to accumulate IP6 in twigs during winter. We conclude that IP6 is the primary storage form of P in poplar trees during winter, and that it may be a common strategy for seasonal P storage in deciduous woody plants. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  5. Increasing the productivity of biomass plantations of Populus species and hybrids in the Pacific Northwest. Final report, September 14, 1981--December 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    DeBell, D.S.; Harrington, C.A.; Clendenen, G.W. [USDA Forest Service, Olympia, WA (United States)] [and others

    1997-08-01

    This final report represents the culmination of eight years of biological research devoted to increasing the productivity of short rotation plantations of Populus trichocarpa and Populus hybrids in the Pacific Northwest. Studies described herein provide an understanding of tree growth, stand development and biomass yield at various spacings, and how patterns thereof differ by Populus clone in monoclonal and polyclonal plantings. Also included is some information about factors related to wind damage in Populus plantings, use of leaf size as a predictor of growth potential, and approaches for estimating tree and stand biomass and biomass growth. The work was accomplished in three research plantations, all established cooperatively with the Washington State Department of Natural Resources (DNR) and located at the DNR Tree Improvement Center near Olympia. The first plantation was established in Spring 1986 to evaluate the highly touted {open_quotes}woodgrass{close_quotes} concept and compare it with more conventional short-rotation management regimes, using two Populus hybrid clones planted at five spacings. Besides providing scientific data to resolve the politicized {open_quotes}wood-grass{close_quotes} dispute, this plantation has furnished excellent data on stand dynamics and woody biomass yield. A second plantation was established at the same time; groups of trees therein received two levels of irrigation and different amounts of four fertilizer amendments, resulting in microsites with diverse moisture and nutrient conditions.

  6. Thidiazuron: A potent cytokinin for efficient plant regeneration in Himalayan poplar (Populus ciliata Wall. using leaf explants

    Directory of Open Access Journals (Sweden)

    Gaurav Aggarwal

    2012-11-01

    Full Text Available Populus species are important resource for certain branches of industry and have special roles for scientific study on biological and agricultural systems. The present investigation was undertaken with an objective of enhancing the frequency of plant regeneration in Himalayan poplar (Populus ciliata Wall.. The effect of Thiadizuron (TDZ alone and in combination with adenine and α-Naphthalene acetic acid (NAA were studied on the regeneration potential of leaf explants. A high efficiency of shoot regeneration was observed in leaf (80.00% explants on MS basal medium supplemented with 0.024 mg/l TDZ and 79.7 mg/l adenine. Elongation and multiplication of shoots were obtained on Murashige and Skoog (MS basal medium, containing 0.5 mg/l 6. Benzyl aminopurine (BAP + 0.2mg/l Indole 3-acetic acid (IAA + 0.3 mg/l Gibberellic acid (GA3. High frequency root regeneration from in vitro developed shoots was observed on MS basal medium supplemented with 0.10 mg/l Indole 3-butyric acid(IBA. Maximum of the in vitro rooted plantlets were well accomplished to the mixture of sand: soil (1:1 and exhibited similar morphology with the field plants. A high efficiency plant regeneration protocol has been developedfrom leaf explants in Himalayan poplar (Populus ciliata Wall..

  7. Aldehyde Dehydrogenase Gene Superfamily in Populus: Organization and Expression Divergence between Paralogous Gene Pairs.

    Directory of Open Access Journals (Sweden)

    Feng-Xia Tian

    Full Text Available Aldehyde dehydrogenases (ALDHs constitute a superfamily of NAD(P+-dependent enzymes that catalyze the irreversible oxidation of a wide range of reactive aldehydes to their corresponding nontoxic carboxylic acids. ALDHs have been studied in many organisms from bacteria to mammals; however, no systematic analyses incorporating genome organization, gene structure, expression profiles, and cis-acting elements have been conducted in the model tree species Populus trichocarpa thus far. In this study, a comprehensive analysis of the Populus ALDH gene superfamily was performed. A total of 26 Populus ALDH genes were found to be distributed across 12 chromosomes. Genomic organization analysis indicated that purifying selection may have played a pivotal role in the retention and maintenance of PtALDH gene families. The exon-intron organizations of PtALDHs were highly conserved within the same family, suggesting that the members of the same family also may have conserved functionalities. Microarray data and qRT-PCR analysis indicated that most PtALDHs had distinct tissue-specific expression patterns. The specificity of cis-acting elements in the promoter regions of the PtALDHs and the divergence of expression patterns between nine paralogous PtALDH gene pairs suggested that gene duplications may have freed the duplicate genes from the functional constraints. The expression levels of some ALDHs were up- or down-regulated by various abiotic stresses, implying that the products of these genes may be involved in the adaptation of Populus to abiotic stresses. Overall, the data obtained from our investigation contribute to a better understanding of the complexity of the Populus ALDH gene superfamily and provide insights into the function and evolution of ALDH gene families in vascular plants.

  8. Root bacterial endophytes alter plant phenotype, but not physiology

    DEFF Research Database (Denmark)

    Henning, Jeremiah A.; Weston, David J.; Pelletier, Dale A.

    2016-01-01

    Plant traits, such as root and leaf area, influence how plants interact with their environment and the diverse microbiota living within plants can influence plant morphology and physiology. Here, we explored how three bacterial strains isolated from the Populus root microbiome, influenced plant...... phenotype. We chose three bacterial strains that differed in predicted metabolic capabilities, plant hormone production and metabolism, and secondary metabolite synthesis. We inoculated each bacterial strain on a single genotype of Populus trichocarpa and measured the response of plant growth related traits...... (root:shoot, biomass production, root and leaf growth rates) and physiological traits (chlorophyll content, net photosynthesis, net photosynthesis at saturating light-Asat, and saturating CO2-Amax). Overall, we found that bacterial root endophyte infection increased root growth rate up to 184% and leaf...

  9. Plants remember past weather: a study for atmospheric pollen concentrations of Ambrosia, Poaceae and Populus

    Science.gov (United States)

    Matyasovszky, István; Makra, László; Csépe, Zoltán; Sümeghy, Zoltán; Deák, Áron József; Pál-Molnár, Elemér; Tusnády, Gábor

    2015-10-01

    After extreme dry (wet) summers or years, pollen production of different taxa may decrease (increase) substantially. Accordingly, studying effects of current and past meteorological conditions on current pollen concentrations for different taxa have of major importance. The purpose of this study is separating the weight of current and past weather conditions influencing current pollen productions of three taxa. Two procedures, namely multiple correlations and factor analysis with special transformation are used. The 11-year (1997-2007) data sets include daily pollen counts of Ambrosia (ragweed), Poaceae (grasses) and Populus (poplar), as well as daily values of four climate variables (temperature, relative humidity, global solar flux and precipitation). Multiple correlations of daily pollen counts with simultaneous values of daily meteorological variables do not show annual course for Ambrosia, but do show definite trends for Populus and Poaceae. Results received using the two methods revealed characteristic similarities. For all the three taxa, the continental rainfall peak and additional local showers in the growing season can strengthen the weight of the current meteorological elements. However, due to the precipitation, big amount of water can be stored in the soil contributing to the effect of the past climate elements during dry periods. Higher climate sensitivity (especially water sensitivity) of the herbaceous taxa ( Ambrosia and Poaceae) can be definitely established compared to the arboreal Populus. Separation of the weight of the current and past weather conditions for different taxa involves practical importance both for health care and agricultural production.

  10. The SHORT-ROOT-like gene PtSHR2B is involved in Populus phellogen activity.

    Science.gov (United States)

    Miguel, Andreia; Milhinhos, Ana; Novák, Ondřej; Jones, Brian; Miguel, Célia M

    2016-03-01

    SHORT-ROOT (SHR) is a GRAS transcription factor first characterized for its role in the specification of the stem cell niche and radial patterning in Arabidopsis thaliana (At) roots. Three SHR-like genes have been identified in Populus trichocarpa (Pt). PtSHR1 shares high similarity with AtSHR over the entire length of the coding sequence. The two other Populus SHR-like genes, PtSHR2A and PtSHR2B, are shorter in their 5' ends when compared with AtSHR. Unlike PtSHR1, that is expressed throughout the cambial zone of greenhouse-grown Populus trees, PtSHR2Bprom:uidA expression was detected in the phellogen. Additionally, PtSHR1 and PtSHR2B expression patterns markedly differ in the shoot apex and roots of in vitro plants. Transgenic hybrid aspen expressing PtSHR2B under the 35S constitutive promoter showed overall reduced tree growth while the proportion of bark increased relative to the wood. Reverse transcription-quantitative PCR (RT-qPCR) revealed increased transcript levels of cytokinin metabolism and response-related genes in the transgenic plants consistent with an increase of total cytokinin levels. This was confirmed by cytokinin quantification by LC-MS/MS. Our results indicate that PtSHR2B appears to function in the phellogen and therefore in the regulation of phellem and periderm formation, possibly acting through modulation of cytokinin homeostasis. Furthermore, this work points to a functional diversification of SHR after the divergence of the Populus and Arabidopsis lineages. This finding may contribute to selection and breeding strategies of cork oak in which, unlike Populus, the phellogen is active throughout the entire tree lifespan, being at the basis of a highly profitable cork industry.

  11. The glutamine synthetase gene family in Populus

    Directory of Open Access Journals (Sweden)

    Cánovas Francisco M

    2011-08-01

    Full Text Available Abstract Background Glutamine synthetase (GS; EC: 6.3.1.2, L-glutamate: ammonia ligase ADP-forming is a key enzyme in ammonium assimilation and metabolism of higher plants. The current work was undertaken to develop a more comprehensive understanding of molecular and biochemical features of GS gene family in poplar, and to characterize the developmental regulation of GS expression in various tissues and at various times during the poplar perennial growth. Results The GS gene family consists of 8 different genes exhibiting all structural and regulatory elements consistent with their roles as functional genes. Our results indicate that the family members are organized in 4 groups of duplicated genes, 3 of which code for cytosolic GS isoforms (GS1 and 1 which codes for the choroplastic GS isoform (GS2. Our analysis shows that Populus trichocarpa is the first plant species in which it was observed the complete GS family duplicated. Detailed expression analyses have revealed specific spatial and seasonal patterns of GS expression in poplar. These data provide insights into the metabolic function of GS isoforms in poplar and pave the way for future functional studies. Conclusions Our data suggest that GS duplicates could have been retained in order to increase the amount of enzyme in a particular cell type. This possibility could contribute to the homeostasis of nitrogen metabolism in functions associated to changes in glutamine-derived metabolic products. The presence of duplicated GS genes in poplar could also contribute to diversification of the enzymatic properties for a particular GS isoform through the assembly of GS polypeptides into homo oligomeric and/or hetero oligomeric holoenzymes in specific cell types.

  12. Changes in photosynthesis, mesophyll conductance to CO2, and isoprenoid emissions in Populus nigra plants exposed to excess nickel.

    Science.gov (United States)

    Velikova, Violeta; Tsonev, Tsonko; Loreto, Francesco; Centritto, Mauro

    2011-05-01

    Poplar (Populus nigra) plants were grown hydroponically with 30 and 200 μM Ni (Ni30 and Ni200). Photosynthesis limitations and isoprenoid emissions were investigated in two leaf types (mature and developing). Ni stress significantly decreased photosynthesis, and this effect depended on the leaf Ni content, which was lower in mature than in developing leaves. The main limitations to photosynthesis were attributed to mesophyll conductance and metabolism impairment. In Ni-stressed developing leaves, isoprene emission was significantly stimulated. We attribute such stimulation to the lower chloroplastic [CO2] than in control leaves. However chloroplastic [CO2] did not control isoprene emission in mature leaves. Ni stress induced the emission of cis-β-ocimene in mature leaves, and of linalool in both leaf types. Induced biosynthesis and emission of isoprenoids reveal the onset of antioxidant processes that may also contribute to reduce Ni stress, especially in mature poplar leaves. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Rooting of hybrid clones of Populus tremula L. x P. tremuloides Michx. by stem cuttings derived from micropropagated plants

    Energy Technology Data Exchange (ETDEWEB)

    Qibin Yu [Univ. of Helsinki (Finland). Dept. of Plant Biology; Maentylae, N. [Univ. of Turku (Finland). Dept. of Biology, Plant Physiology and Molecular Biology; Salonen, M. [Finnish Forest Research Inst., Laeyliaeinen (Finland). Haapastensyrjae Breeding Station

    2001-07-01

    Propagation costs could be cut by replacing part of the micropropagation process with steps involving more traditional techniques. This study explored possibilities for improving existing vegetative propagation techniques for aspen using stem cuttings obtained from micropropagated plants. Vegetative propagation through stem cuttings was studied in 10 micropropagated hybrid aspen clones (Populus tremula L. x P. tremuloides Michx). Cuttings containing one axillary bud were harvested from the same donor plants twice during the growing season: the first harvest in May and the second harvest in July. Rooting percentage was correlated positively with root length, number of roots and height of cutting plant but negatively with length of rooting. The average rooting percentage was 53% in the first harvest and 27% in second harvest. Indole-3-butyric acid treatments (1.2 mM) significantly improved rooting in the second harvest, but not in the first harvest, suggesting different endogenous auxin levels in the cuttings. A significant variation for most traits related to rooting ability was found among the clones, indicating that clonal effects play an important role in the propagation of aspen. Thus, clones with a good response in shoot growth and rooting could be exploited in large-scale propagation using stem cuttings.

  14. Populus euphratica XTH overexpression enhances salinity tolerance by the development of leaf succulence in transgenic tobacco plants.

    Science.gov (United States)

    Han, Yansha; Wang, Wei; Sun, Jian; Ding, Mingquan; Zhao, Rui; Deng, Shurong; Wang, Feifei; Hu, Yue; Wang, Yang; Lu, Yanjun; Du, Liping; Hu, Zanmin; Diekmann, Heike; Shen, Xin; Polle, Andrea; Chen, Shaoliang

    2013-11-01

    Populus euphratica is a salt-tolerant tree species that develops leaf succulence after a prolonged period of salinity stress. In the present study, a putative xyloglucan endotransglucosylase/hydrolase gene (PeXTH) from P. euphratica was isolated and transferred to tobacco plants. PeXTH localized exclusively to the endoplasmic reticulum and cell wall. Plants overexpressing PeXTH were more salt tolerant than wild-type tobacco with respect to root and leaf growth, and survival. The increased capacity for salt tolerance was due mainly to the anatomical and physiological alterations caused by PeXTH overexpression. Compared with the wild type, PeXTH-transgenic plants contained 36% higher water content per unit area and 39% higher ratio of fresh weight to dry weight, a hallmark of leaf succulence. However, the increased water storage in the leaves in PeXTH-transgenic plants was not accompanied by greater leaf thickness but was due to highly packed palisade parenchyma cells and fewer intercellular air spaces between mesophyll cells. In addition to the salt dilution effect in response to NaCl, these anatomical changes increased leaf water-retaining capacity, which lowered the increase of salt concentration in the succulent tissues and mesophyll cells. Moreover, the increased number of mesophyll cells reduced the intercellular air space, which improved carbon economy and resulted in a 47-78% greater net photosynthesis under control and salt treatments (100-150 mM NaCl). Taken together, the results indicate that PeXTH overexpression enhanced salt tolerance by the development of succulent leaves in tobacco plants without swelling.

  15. Map and analysis of microsatellites in the genome of Populus: The first sequenced perennial plant

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    We mapped and analyzed the microsatellites throughout 284295605 base pairs of the unambiguously assembled sequence scaffolds along 19 chromosomes of the haploid poplar genome. Totally, we found 150985 SSRs with repeat unit lengths between 2 and 5 bp. The established microsatellite physical map demonstrated trat SSRs were distributed relatively evenly across the genome of Populus. On average, These SSRs occurred every 1883 bp within the poplar genome and the SSR densities in intergenic regions, introns, exons and UTRs were 85.4%, 10.7%, 2.7% and 1.2%, respectively. We took di-, tri-, tetra-and pentamers as the four classes of repeat units and found that the density of each class of SSRs decreased with the repeat unit lengths except for the tetranucleotide repeats. It was noteworthy that the length diversification of microsatellite sequences was negatively correlated with their repeat unit length and the SSRs with shorter repeat units gained repeats faster than the SSRs with longer repeat units. We also found that the GC content of poplar sequence significantly correlated with densities of SSRs with uneven repeat unit lengths (tri- and penta-), but had no significant correlation with densities of SSRs with even repeat unit lengths (di- and tetra-). In poplar genome, there were evidences that the occurrence of different microsatellites was under selection and the GC content in SSR sequences was found to significantly relate to the functional importance of microsatellites.

  16. Aspen (Populus tremuloides Michx.) intake and preference by mammalian herbivores: the role of plant secondary compounds and nutritional context.

    Science.gov (United States)

    Villalba, Juan J; Burritt, Elizabeth A; St Clair, Samuel B

    2014-10-01

    Aspen (Populus tremuloides Michx.) has evolved a chemical defense system comprised of phenolic glycosides (PG), which effectively deter insect herbivory. However, much less is known about the role of PG and the nutritional quality of the associated plant community on aspen browse susceptibility to mammalian herbivores. In three successive periods during the growing season, we conducted experiments with sheep by offering leaves from two aspen stands with different concentrations of PG (LOW, HIGH) or aspen leaves vs. leaves from a forb (Utah pea, Lathyrus pauciflorus) or a grass (smooth brome, Bromus inermis Leyss.) growing in an aspen understory. Intake of aspen (19 to 35 % PG) was low in all periods (1 to 6 g/Kg(0.75) in 2 hr) supporting the notion that aspen's defense system may contribute to its ecological success. However, lambs ate larger amounts of LOW than of HIGH suggesting that sheep could discriminate between aspen stands with different concentrations of PG, even when both stands were relatively well defended. Concentration of nutrients and chemical defenses in aspen leaves remained fairly stable across the growing season, and preference for aspen increased over the growing season. In contrast, preference for the forb and the grass decreased across the growing season in concert with a decline in the nutritional quality of these plants. The data suggest that nutritional context of aspen and associated forage species drove preference more than contrasts in defense chemistry of aspen. There may be periods of "susceptibility" of aspen use by mammalian herbivores, despite high concentrations of chemical defenses, which can potentially be targeted by management to reduce aspen herbivory.

  17. Establishment of high frequency shoot regeneration system in Himalayan poplar (Populus ciliata Wall. ex Royle) from petiole explants using Thidiazuron cytokinin as plant growth regulator

    Institute of Scientific and Technical Information of China (English)

    G Aggarwal; A Gaur; D K Srivastava

    2015-01-01

    Populus species are important resources for industry and in scientific study on biological and agricul-tural systems. Our objective was to enhance the frequency of plant regeneration in Himalayan poplar (Populus ciliata wall. ex Royle). The effect of TDZ alone and in combi-nation with adenine and NAA was studied on the regen-eration potential of petiole explants. The explants were excised from Himalayan poplar plants grown in glass-houses. After surface sterilization the explants were cul-tured on shoot induction medium. High percentage shoot regeneration (86%) was recorded on MS medium sup-plemented with 0.004 mg L-1 TDZ and 79.7 mg L-1 adenine. The regenerated shoots for elongation and multi-plication were transferred to MS ? 0.5 mg L-1 BAP ? 0.2 mg L-1 IAA ? 0.3 mg L-1 GA3. Root re-generation from shoots developed in vitro was observed on MS medium supplemented with 0.10 mg L-1 IBA. Hi-malayan poplar plantlets could be produced within 2 months after acclimatization in a sterile mixture of sand and soil. We developed a high efficiency plant regeneration protocol from petiole explants of P. ciliata.

  18. Intron-mediated alternative splicing of WOOD-ASSOCIATED NAC TRANSCRIPTION FACTOR1B regulates cell wall thickening during fiber development in Populus species.

    Science.gov (United States)

    Zhao, Yunjun; Sun, Jiayan; Xu, Peng; Zhang, Rui; Li, Laigeng

    2014-02-01

    Alternative splicing is an important mechanism involved in regulating the development of multicellular organisms. Although many genes in plants undergo alternative splicing, little is understood of its significance in regulating plant growth and development. In this study, alternative splicing of black cottonwood (Populus trichocarpa) wood-associated NAC domain transcription factor (PtrWNDs), PtrWND1B, is shown to occur exclusively in secondary xylem fiber cells. PtrWND1B is expressed with a normal short-transcript PtrWND1B-s as well as its alternative long-transcript PtrWND1B-l. The intron 2 structure of the PtrWND1B gene was identified as a critical sequence that causes PtrWND1B alternative splicing. Suppression of PtrWND1B expression specifically inhibited fiber cell wall thickening. The two PtrWND1B isoforms play antagonistic roles in regulating cell wall thickening during fiber cell differentiation in Populus spp. PtrWND1B-s overexpression enhanced fiber cell wall thickening, while overexpression of PtrWND1B-l repressed fiber cell wall thickening. Alternative splicing may enable more specific regulation of processes such as fiber cell wall thickening during wood formation.

  19. Genome-wide Identification of TCP Family Transcription Factors from Populus euphratica and Their Involvement in Leaf Shape Regulation.

    Science.gov (United States)

    Ma, Xiaodong; Ma, Jianchao; Fan, Di; Li, Chaofeng; Jiang, Yuanzhong; Luo, Keming

    2016-09-08

    Higher plants have been shown to experience a juvenile vegetative phase, an adult vegetative phase, and a reproductive phase during its postembryonic development and distinct lateral organ morphologies have been observed at the different development stages. Populus euphratica, commonly known as a desert poplar, has developed heteromorphic leaves during its development. The TCP family genes encode a group of plant-specific transcription factors involved in several aspects of plant development. In particular, TCPs have been shown to influence leaf size and shape in many herbaceous plants. However, whether these functions are conserved in woody plants remains unknown. In the present study, we carried out genome-wide identification of TCP genes in P. euphratica and P. trichocarpa, and 33 and 36 genes encoding putative TCP proteins were found, respectively. Phylogenetic analysis of the poplar TCPs together with Arabidopsis TCPs indicated a biased expansion of the TCP gene family via segmental duplications. In addition, our results have also shown a correlation between different expression patterns of several P. euphratica TCP genes and leaf shape variations, indicating their involvement in the regulation of leaf shape development.

  20. Changes in photosynthesis, mesophyll conductance to CO{sub 2}, and isoprenoid emissions in Populus nigra plants exposed to excess nickel

    Energy Technology Data Exchange (ETDEWEB)

    Velikova, Violeta, E-mail: violet@obzor.bio21.bas.bg [Bulgarian Academy of Sciences, Acad. M. Popov Institute of Plant Physiology, Acad. G. Bonchev, Bl. 21, 1113 Sofia (Bulgaria); Tsonev, Tsonko [Bulgarian Academy of Sciences, Acad. M. Popov Institute of Plant Physiology, Acad. G. Bonchev, Bl. 21, 1113 Sofia (Bulgaria); Loreto, Francesco [Consiglio Nazionale delle Ricerche, Istituto per la Protezione delle Piante, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Firenze (Italy); Centritto, Mauro [Consiglio Nazionale delle Ricerche, Istituto di Biologia Agroambientale e Forestale, 00015 Monterotondo Scalo (RM) (Italy)

    2011-05-15

    Poplar (Populus nigra) plants were grown hydroponically with 30 and 200 {mu}M Ni (Ni{sub 30} and Ni{sub 200}). Photosynthesis limitations and isoprenoid emissions were investigated in two leaf types (mature and developing). Ni stress significantly decreased photosynthesis, and this effect depended on the leaf Ni content, which was lower in mature than in developing leaves. The main limitations to photosynthesis were attributed to mesophyll conductance and metabolism impairment. In Ni-stressed developing leaves, isoprene emission was significantly stimulated. We attribute such stimulation to the lower chloroplastic [CO{sub 2}] than in control leaves. However chloroplastic [CO{sub 2}] did not control isoprene emission in mature leaves. Ni stress induced the emission of cis-{beta}-ocimene in mature leaves, and of linalool in both leaf types. Induced biosynthesis and emission of isoprenoids reveal the onset of antioxidant processes that may also contribute to reduce Ni stress, especially in mature poplar leaves. - Graphical abstract: Visible damage caused by Ni treatment. 1 - Ni{sub 0} (control plants); 2 - Ni{sub 200}; M = mature and D = developing Populus nigra leaves. Display Omitted Highlights: > We study the effect of Ni pollution on photosynthesis and isoprenoid emissions. > Ni stress significantly decreases photosynthesis. The main limitations are attributed to mesophyll conductance and metabolism impairment. > Constitutive isoprene emission was significantly stimulated in Ni-stressed leaves. Exposure to enhanced Ni concentration induces cis-beta-ocimene and linalool emissions. - The study reveals consequences of Ni stress on plant physiology, namely increasing diffusional limitation to photosynthesis and isoprenoid emissions.

  1. Root bacterial endophytes alter plant phenotype, but not physiology

    Directory of Open Access Journals (Sweden)

    Jeremiah A. Henning

    2016-11-01

    Full Text Available Plant traits, such as root and leaf area, influence how plants interact with their environment and the diverse microbiota living within plants can influence plant morphology and physiology. Here, we explored how three bacterial strains isolated from the Populus root microbiome, influenced plant phenotype. We chose three bacterial strains that differed in predicted metabolic capabilities, plant hormone production and metabolism, and secondary metabolite synthesis. We inoculated each bacterial strain on a single genotype of Populus trichocarpa and measured the response of plant growth related traits (root:shoot, biomass production, root and leaf growth rates and physiological traits (chlorophyll content, net photosynthesis, net photosynthesis at saturating light–Asat, and saturating CO2–Amax. Overall, we found that bacterial root endophyte infection increased root growth rate up to 184% and leaf growth rate up to 137% relative to non-inoculated control plants, evidence that plants respond to bacteria by modifying morphology. However, endophyte inoculation had no influence on total plant biomass and photosynthetic traits (net photosynthesis, chlorophyll content. In sum, bacterial inoculation did not significantly increase plant carbon fixation and biomass, but their presence altered where and how carbon was being allocated in the plant host.

  2. The influence of alternative plant propagation and stand establishment techniques on survival and growth of eastern cottonwood (Populus deltoides Bartr.) clones.

    Energy Technology Data Exchange (ETDEWEB)

    Kaczmarek, Donald J.; et. al.,

    2014-02-09

    Four eastern cottonwood clones, including standard operational clone ST66 and three advanced clonal selections were produced and included in a test utilizing five different plant propagation methods. Despite relatively large first-year growth differences among clones, all clones demonstrated similar responses to the treatments and clone 9 cutting treatment interactions were generally non-significant. The effects of changing cutting lengths are consistent with previous studies which indicated the potential for increased plant survival and growth with increased cutting lengths. Differences in stored carbohydrate reserves alone do not appear to completely control first-year growth and development of cuttings. First-year growth of 51 cm long cuttings planted 30.5 cm deep was greater than the same cuttings planted 48 cm deep. Stem form of plants derived from whip-tip propagation did not differ from plants derived from standard, unrooted cuttings. This propagation method offers the potential of far greater production capacity from a cutting orchard and rapid bulk-up of new or limited clones. Stand uniformity assessments suggest that surviving trees of each individual cutting treatment exhibit similar levels of growth variation. Optimization of plantation establishment techniques has the potential to increase growth of young Populus plantations.

  3. Denitrification by plant roots? New aspects of plant plasma membrane-bound nitrate reductase.

    Science.gov (United States)

    Eick, Manuela; Stöhr, Christine

    2012-10-01

    A specific form of plasma membrane-bound nitrate reductase in plants is restricted to roots. Two peptides originated from plasma membrane integral proteins isolated from Hordeum vulgare have been assigned as homologues to the subunit NarH of respiratory nitrate reductase of Escherichia coli. Corresponding sequences have been detected for predicted proteins of Populus trichocarpa with high degree of identities for the subunits NarH (75%) and NarG (65%), however, with less accordance for the subunit NarI. These findings coincide with biochemical properties, particularly in regard to the electron donors menadione and succinate. Together with the root-specific and plasma membrane-bound nitrite/NO reductase, nitric oxide is produced under hypoxic conditions in the presence of nitrate. In this context, a possible function in nitrate respiration of plant roots and an involvement of plants in denitrification processes are discussed.

  4. Vapour pressure deficit during growth has little impact on genotypic differences of transpiration efficiency at leaf and whole-plant level: an example from Populus nigra L.

    Science.gov (United States)

    Rasheed, Fahad; Dreyer, Erwin; Richard, Béatrice; Brignolas, Franck; Brendel, Oliver; Le Thiec, Didier

    2015-04-01

    Poplar genotypes differ in transpiration efficiency (TE) at leaf and whole-plant level under similar conditions. We tested whether atmospheric vapour pressure deficit (VPD) affected TE to the same extent across genotypes. Six Populus nigra genotypes were grown under two VPD. We recorded (1) (13)C content in soluble sugars; (2) (18)O enrichment in leaf water; (3) leaf-level gas exchange; and (4) whole-plant biomass accumulation and water use. Whole-plant and intrinsic leaf TE and (13)C content in soluble sugars differed significantly among genotypes. Stomatal conductance contributed more to these differences than net CO2 assimilation rate. VPD increased water use and reduced whole-plant TE. It increased intrinsic leaf-level TE due to a decline in stomatal conductance. It also promoted higher (18)O enrichment in leaf water. VPD had no genotype-specific effect. We detected a deviation in the relationship between (13)C in leaf sugars and (13)C predicted from gas exchange and the standard discrimination model. This may be partly due to genotypic differences in mesophyll conductance, and to its lack of sensitivity to VPD. Leaf-level (13)C discrimination was a powerful predictor of the genetic variability of whole-plant TE irrespective of VPD during growth. © 2014 John Wiley & Sons Ltd.

  5. Taxonomy Icon Data: black cottonwood [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available black cottonwood Populus trichocarpa Populus_trichocarpa_L.png Populus_trichocarpa_...NL.png Populus_trichocarpa_S.png Populus_trichocarpa_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i...=Populus+trichocarpa&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Populus+trichocarpa&t=NL http://bi...osciencedbc.jp/taxonomy_icon/icon.cgi?i=Populus+trichocarpa&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Populus+trichocarpa&t=NS ...

  6. Increased belowground C release during initial plant development of Populus deltoides x nigra grown under light and C reserve limited conditions

    Science.gov (United States)

    Studer, Mirjam S.; Siegwolf, Rolf T. W.; Schmidt, Michael W. I.; Abiven, Samuel

    2014-05-01

    Plants might be a key factor for the long-term stabilisation of carbon (C) in the soil, e.g. through enhanced physical protection of root-derived C against microbial decomposition in soil aggregates. On the other hand C released by the plants into the soil might promote the decomposition of native soil organic matter (SOM) through the stimulation of microbial activity. We measured the C budget of developing plant-soil systems (Populus deltoides x nigra, Cambisol soil) in the laboratory under controlled environmental conditions. In order to distinguish plant-derived from native C in the SOM and the soil CO2 efflux, we labelled the poplar shoots continuously with 13C-CO2 from first emergence of leaves (sprouting from stem cuttings). Throughout the experiment the CO2 fluxes (photosynthetic assimilation, dark respiratory loss, soil CO2 efflux) were measured frequently (every 30 min) and the 13C was traced in the soil CO2 efflux (1-2 times a week). After 10 weeks the plant-soil systems were destructively harvested and the distribution of the 13C distribution was analysed. The plants developed slowly (compared to previous experiments), most likely due to limitation in C reserves (long term cutting storage) and C supply (low light intensities). The amount of 13C recovered in the roots, microbial biomass and soil CO2 efflux was directly correlated with the leaf area of the different plant individuals. After 3-4 weeks of plant development we observed a high peak in the total soil CO2 efflux. During this time the relative belowground C release was increased massively over the basal rate of 17 % of net C assimilated, whereby the variability between the plant individuals was large. The smallest plants, i.e. the plants that were most resource limited, obtained the highest belowground C release accounting at the peak time for up to 57 % of net assimilated C. We hypothesize that the plants released specific compounds, which either directly (enzymatically) or indirectly (priming

  7. Somatic embryogenesis and plant regeneration from cell suspension and tissue cultures of mature himalayan poplar (Populus ciliata).

    Science.gov (United States)

    Cheema, G S

    1989-02-01

    Somatic embryogenesis and plantlet formation were obtained from callus and cell suspension cultures of 40-year- old Himalayan Poplar (Populus ciliata Wall ex Royle). Callus and cell suspensions were obtained by transfer of inoculum of semiorganized leaf cultures, which were maintained on Murashige and Skoog (MS) medium supplemented with benzylaminopurine (BAP), to MS with 2,4-dichlorophenoxyacetic acid (2,4-D). Reduction of 2,4-D concentration during subsequent subculture of cell suspensions resulted in the formation of embryoids. These embryoids developed further only after being transferred to agar-based MS medium supplemented with BAP and naphthalene acetic acid. Loss of embryogenic potential was observed in cell suspensions after 6 subcultures. However, callus cultures retained the embryogenic potential even after repeated subcultures for more than a year. Plantlets could be successfully hardened and grown in natural outdoor conditions.

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

    Directory of Open Access Journals (Sweden)

    Yuepeng Song

    Full Text Available 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.

  9. Highly efficient isolation of Populus mesophyll protoplasts and its application in transient expression assays.

    Directory of Open Access Journals (Sweden)

    Jianjun Guo

    Full Text Available BACKGROUND: Populus is a model woody plant and a promising feedstock for lignocellulosic biofuel production. However, its lengthy life cycle impedes rapid characterization of gene function. METHODOLOGY/PRINCIPAL FINDINGS: We optimized a Populus leaf mesophyll protoplast isolation protocol and established a Populus protoplast transient expression system. We demonstrated that Populus protoplasts are able to respond to hormonal stimuli and that a series of organelle markers are correctly localized in the Populus protoplasts. Furthermore, we showed that the Populus protoplast transient expression system is suitable for studying protein-protein interaction, gene activation, and cellular signaling events. CONCLUSIONS/SIGNIFICANCE: This study established a method for efficient isolation of protoplasts from Populus leaf and demonstrated the efficacy of using Populus protoplast transient expression assays as an in vivo system to characterize genes and pathways.

  10. Highly Efficient Isolation of Populus Mesophyll Protoplasts and Its Application in Transient Expression Assays

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jianjun [ORNL; Morrell-Falvey, Jennifer L [ORNL; Labbe, Jessy L [ORNL; Muchero, Wellington [ORNL; Kalluri, Udaya C [ORNL; Tuskan, Gerald A [ORNL; Chen, Jay [ORNL

    2012-01-01

    Background: Populus is a model woody plant and a promising feedstock for lignocellulosic biofuel production. However, its lengthy life cycle impedes rapid characterization of gene function. Methodology/Principal Findings: We optimized a Populus leaf mesophyll protoplast isolation protocol and established a Populus protoplast transient expression system. We demonstrated that Populus protoplasts are able to respond to hormonal stimuli and that a series of organelle markers are correctly localized in the Populus protoplasts. Furthermore, we showed that the Populus protoplast transient expression system is suitable for studying protein-protein interaction, gene activation, and cellular signaling events. Conclusions/Significance: This study established a method for efficient isolation of protoplasts from Populus leaf and demonstrated the efficacy of using Populus protoplast transient expression assays as an in vivo system to characterize genes and pathways.

  11. Genome-wide association mapping for wood characteristics in Populus identifies an array of candidate single nucleotide polymorphisms.

    Science.gov (United States)

    Porth, Ilga; Klapšte, Jaroslav; Skyba, Oleksandr; Hannemann, Jan; McKown, Athena D; Guy, Robert D; DiFazio, Stephen P; Muchero, Wellington; Ranjan, Priya; Tuskan, Gerald A; Friedmann, Michael C; Ehlting, Juergen; Cronk, Quentin C B; El-Kassaby, Yousry A; Douglas, Carl J; Mansfield, Shawn D

    2013-11-01

    Establishing links between phenotypes and molecular variants is of central importance to accelerate genetic improvement of economically important plant species. Our work represents the first genome-wide association study to the inherently complex and currently poorly understood genetic architecture of industrially relevant wood traits. Here, we employed an Illumina Infinium 34K single nucleotide polymorphism (SNP) genotyping array that generated 29,233 high-quality SNPs in c. 3500 broad-based candidate genes within a population of 334 unrelated Populus trichocarpa individuals to establish genome-wide associations. The analysis revealed 141 significant SNPs (α ≤ 0.05) associated with 16 wood chemistry/ultrastructure traits, individually explaining 3-7% of the phenotypic variance. A large set of associations (41% of all hits) occurred in candidate genes preselected for their suggested a priori involvement with secondary growth. For example, an allelic variant in the FRA8 ortholog explained 21% of the total genetic variance in fiber length, when the trait's heritability estimate was considered. The remaining associations identified SNPs in genes not previously implicated in wood or secondary wall formation. Our findings provide unique insights into wood trait architecture and support efforts for population improvement based on desirable allelic variants.

  12. Protein (Viridiplantae): 224129758 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available predicted protein Populus trichocarpa MAKEMPAMKRALCEWMIVEEFPSWFKADNEWKAELCRLCNLESTEDLELGWRDMVNKFELVWKGEPRKKYKKPRPKVRVGLPKKICQYFDDRIGREENEVIVVLGSRGDSFCLALRFLNSNWVQKPGKHNQGQQQKLK ...

  13. Protein (Viridiplantae): 224138986 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available icted protein Populus trichocarpa MALDIKTFETIIPSCFLSFTIPNPVLPTHLLRVAVLDSSIQFTESPQIATLLVSQTREPDWIFSTESGHLQLLLSSPEISQLILIGNNRINGSDSSLLTYHKRDNTQYVKSLENSLKPLFFALSPKVSVKDGIFDCSVLDDALIHLH ...

  14. Effects of two iron sources on iron and cadmium allocation in poplar (populus alba) plants exposed to cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Fodor, F.; Gaspar, L.; Cseh, E.; Sarvari, E. [Eotvos Univ., Budapest (Hungary). Dept. of Plant Physiology; Morales, F.; Gogorcena, Y.; Abadia, J. [Consejo Superior de Investigaciones Cientificas, Zaragoza (Spain). Dept. de Nutricion Vegetal; Lucena, J.J. [Madrid Univ., Madrid (Spain). Dept. de Quimica Agricola; Kropfl, K. [Eotvos Univ., Budapest (Hungary). Dept. of Technology and Environmental Chemistry

    2005-09-01

    The phytotoxicity of heavy metals is often manifested as inhibition of plant growth, nitrate assimilation and photosynthesis, as well as disturbances in plant ion and water balances. Many of these plant responses are a result of inhibition of enzyme activity caused by the binding of heavy metal ions to sulfhydryl groups in the active sites of enzymes and by substitution of essential metals. This study investigated the effects of cadmium (Cd) nitrate on the utilization and allocation of iron (Fe) in poplar plants grown in a nutrient solution with Fe(III)-EDTA or Fe(III)-citrate as the Fe source. The effects of Cd were also compared with those of Fe deprivation. Results indicated that the accumulation of Fe in roots was 10-fold higher in plants grown with Fe-citrate than with Fe-ETDA. In addition, cadmium increased leaf chlorophyll concentrations and photosynthetic rates, and these decreases were more marked in plants grown with Fe-citrate than with Fe-EDTA. In both treatments, addition of Cd caused large increases in root and shoot apoplasmic and non-apoplasmic Cd contents and increases in root Fe content. However, Cd decreased shoot Fe content, especially in plants grown with Fe-citrate. New leaves of plants grown with Fe-citrate had small cellular Fe pools, whereas these pools were large in new leaves of plants grown with Fe-EDTA. Non-apoplasmic Cd pools in new leaves were smaller in plants grown with Fe-citrate than with Fe-EDTA, which indicated that inactivation of non-apoplasmic Cd pools is facilitated more by Fe-EDTA than by Fe-citrate. In the presence of Cd, Fe-EDTA was also superior to Fe-citrate in maintaining an adequate Fe supply to poplar shoots. It was concluded that because the amount of non-apoplasmic root Fe was higher in plants grown with Fe-citrate than with Fe-EDTA, the observed differences in plant responses to Fe-EDTA and Fe-citrate may reflect distances in long-distance transport of Fe rather than its acquisition of Fe by roots. 42 refs., 6

  15. Dragon TIS Spotter: An Arabidopsis-derived predictor of translation initiation sites in plants

    KAUST Repository

    Magana-Mora, Arturo

    2012-10-30

    In higher eukaryotes, the identification of translation initiation sites (TISs) has been focused on finding these signals in cDNA or mRNA sequences. Using Arabidopsis thaliana (A.t.) information, we developed a prediction tool for signals within genomic sequences of plants that correspond to TISs. Our tool requires only genome sequence, not expressed sequences. Its sensitivity/specificity is for A.t. (90.75%/92.2%), for Vitis vinifera (66.8%/94.4%) and for Populus trichocarpa (81.6%/94.4%), which suggests that our tool can be used in annotation of different plant genomes. We provide a list of features used in our model. Further study of these features may improve our understanding of mechanisms of the translation initiation. The Author(s) 2012. Published by Oxford University Press.

  16. Leaf water relations and sapflow in eastern cottonwood (Populus deltoides Bartr.) trees planted for phytoremediation of a groundwater pollutant

    Science.gov (United States)

    James M. Vose; Wayne T. Swank; Gregory J. Harvey; Barton D. Clinton; Christine Sobek

    2000-01-01

    Plants that remediate groundwater pollutants may offer a feasible alternative to the traditional and more expensive practices. Because its success depends on water use, this approach requires a complete understanding of species-specific transpiration patterns. The objectives of this study were (1) to quantify tree and stand-level transpiration in two age classes (whips...

  17. Genome-wide analysis of the fasciclin-like arabinogalactan protein gene family reveals differential expression patterns, localization and salt stress response in Populus

    Directory of Open Access Journals (Sweden)

    Lina eZang

    2015-12-01

    Full Text Available Fasciclin-like arabinogalactan proteins (FLAs are a subclass of arabinogalactan proteins (AGPs involved in plant growth, development and response to abiotic stress. Although many studies have been performed to identify molecular functions of individual family members, little information is available on genome-wide identification and characterization of FLAs in the genus Populus. Based on genome-wide analysis, we have identified 35 Populus FLAs which were distributed on 16 chromosomes and phylogenetically clustered into four major groups. Gene structure and motif composition were relatively conserved in each group. All the members contained N-terminal signal peptide, 23 of which included predicted glycosylphosphatidylinositol (GPI modification sites and were anchored to plasma membranes. Subcellular localization analysis showed that PtrFLA2/20/26 were localized in cell membrane and cytoplasm of protoplasts from Populus stem-differentiating xylem. The Ka/Ks ratios showed that purifying selection has played a leading role in the long-term evolutionary period which greatly maintained the function of this family. The expression profiles showed that 32 PtrFLAs were differentially expressed in four tissues at four seasons based on publicly available microarray data. 18 FLAs were further verified with qRT-PCR in different tissues, which indicated that PtrFLA1/2/3/7/11/12/20/21/22/24/26/30 were significantly expressed in male and female flowers, suggesting close correlations with the reproductive development. In addition, PtrFLA1/9/10/11/17/21/23/24/26/28 were highly expressed in the stems and differentiating xylem, which may be involved in stem development. To determine salt response of FLAs, qRT-PCR was performed to analyze the expression of 18 genes under salinity stress across two time points. Results demonstrated that all the 18 FLAs were expressed in root tissues; especially, PtrFLA2/12/20/21/24/30 were significantly induced at different time

  18. Genome anchored QTLs for biomass productivity in hybrid Populus grown under contrasting environments.

    Directory of Open Access Journals (Sweden)

    Wellington Muchero

    Full Text Available Traits related to biomass production were analyzed for the presence of quantitative trait loci (QTLs in a Populus trichocarpa × P. deltoides F(2 population. A genetic linkage map composed of 841 SSR, AFLP, and RAPD markers and phenotypic data from 310 progeny were used to identify genomic regions harboring biomass QTLs. Twelve intervals were identified, of which BM-1, BM-2, and BM-7 were identified in all three years for both height and diameter. One putative QTL, BM-7, and one suggestive QTL exhibited significant evidence of over-dominance in all three years for both traits. Conversely, QTLs BM-4 and BM-6 exhibited evidence of under-dominance in both environments for height and diameter. Seven of the nine QTLs were successfully anchored, and QTL peak positions were estimated for each one on the P. trichocarpa genome assembly using flanking SSR markers with known physical positions. Of the 3,031 genes located in genome-anchored QTL intervals, 1,892 had PFAM annotations. Of these, 1,313, representing 255 unique annotations, had at least one duplicate copy in a QTL interval identified on a separate scaffold. This observation suggests that some QTLs identified in this study may have shared the same ancestral sequence prior to the salicoid genome duplication in Populus.

  19. Identification of quantitative trait loci and candidate genes for cadmium tolerance in Populus

    Energy Technology Data Exchange (ETDEWEB)

    Induri, Brahma R [West Virginia University; Ellis, Danielle R [West Virginia University; Slavov, Goncho T. [West Virginia University; Yin, Tongming [ORNL; Zhang, Xinye [ORNL; Tuskan, Gerald A [ORNL; DiFazio, Steven P [West Virginia University

    2012-01-01

    Understanding genetic variation for the response of Populus to heavy metals like cadmium (Cd) is an important step in elucidating the underlying mechanisms of tolerance. In this study, a pseudo-backcross pedigree of Populus trichocarpa Torr. & Gray and Populus deltoides Bart. was characterized for growth and performance traits after Cd exposure. A total of 16 quantitative trait loci (QTL) at logarithm of odds (LOD) ratio 2.5 were detected for total dry weight, its components and root volume. Major QTL for Cd responses were mapped to two different linkage groups and the relative allelic effects were in opposing directions on the two chromosomes, suggesting differential mechanisms at these two loci. The phenotypic variance explained by Cd QTL ranged from 5.9 to 11.6% and averaged 8.2% across all QTL. A whole-genome microarray study led to the identification of nine Cd-responsive genes from these QTL. Promising candidates for Cd tolerance include an NHL repeat membrane-spanning protein, a metal transporter and a putative transcription factor. Additional candidates in the QTL intervals include a putative homolog of a glutamate cysteine ligase, and a glutathione-S-transferase. Functional characterization of these candidate genes should enhance our understanding of Cd metabolism and transport and phytoremediation capabilities of Populus.

  20. Barcoding poplars (Populus L. from western China.

    Directory of Open Access Journals (Sweden)

    Jianju Feng

    plants, especially for taxonomic groups that have complex evolutionary histories (e.g. Populus.

  1. Draft Genome Sequence of Pantoea ananatis GB1, a Plant-Growth-Promoting Hydrocarbonoclastic Root Endophyte, Isolated at a Diesel Fuel Phytoremediation Site Planted with Populus.

    Science.gov (United States)

    Gkorezis, Panagiotis; Van Hamme, Jonathan D; Bottos, Eric M; Thijs, Sofie; Balseiro-Romero, Maria; Monterroso, Carmela; Kidd, Petra Suzan; Rineau, Francois; Weyens, Nele; Vangronsveld, Jaco

    2016-02-25

    We report the 4.76-Mb draft genome of Pantoea ananatis GB1, a Gram-negative bacterium of the family Enterobacteriaceae, isolated from the roots of poplars planted for phytoremediation of a diesel-contaminated plume at the Ford Motor Company site in Genk, Belgium. Strain GB1 promotes plant growth in various hosts and metabolizes hydrocarbons.

  2. Effect of Alnus glutinosa on hybrid populus growth and soil nitrogen concentration in a mixed plantation

    Science.gov (United States)

    Jeffrey O. Dawson; Edward A. Hansen

    1983-01-01

    Height growth of hybrid Populusand soil nitrogen concentration around Alnus glutinosa stems differed significantly both spatially and with the Alnus/Populus mixture in a short-rotation intensively cultured mixed planting. Populus height growth comparable to that obtained from optimal rates of...

  3. Effect of temperature on the occurrence of O/sub 2/ and CO/sub 2/ insensitive photosynthesis in field grown plants. [Phaseolus vulgaris; Capsicum annum; Lycopersicon esculentum, Scrophularia desertorum; Cardaria draba, Populus fremontii

    Energy Technology Data Exchange (ETDEWEB)

    Sage, R.F.; Sharkey, T.D.

    1987-07-01

    The sensitivity of photosynthesis to O/sub 2/ and CO/sub 2/ was measured in leaves from field grown plants of six species (Phaseolus vulgaris, Capsicum annuum, Lycopersicon esculentum, Scrophularia desertorum, Cardaria draba, and Populus fremontii) from 5/sup 0/C to 35/sup 0/C using gas-exchange techniques. In all species but Phaseolus, photosynthesis was insensitive to O/sub 2/ in normal air below a species dependent temperature. CO/sub 2/ insensitivity occurred under the same conditions that resulted in O/sub 2/ insensitivity. A complete loss of O/sub 2/ sensitivity occurred up to 22/sup 0/C in Lycopersicon but only up to 6/sup 0/C in Scrophularia. In Lycopersicon and Populus, O/sub 2/ and CO/sub 2/ insensitivity occurred under conditions regularly encountered during the cooler portions of the day. Because O/sub 2/ insensitivity is an indicator of feedback limited photosynthesis, these results indicate that feedback limitations can play a role in determining the diurnal carbon gain in the field. At higher partial pressures of CO/sub 2/ the temperature at which O/sub 2/ insensitivity occurred was higher, indicating that feedback limitations in the field will become more important as the CO/sub 2/ concentration in the atmosphere increases.

  4. Plant growth regulators in poplar clones differing in resistance to the fungus Ceratocystis fimbriata Ell. et Haist

    Directory of Open Access Journals (Sweden)

    Jadwiga Stopińska

    2014-02-01

    Full Text Available In poplar clones with different resistance to the fungus Ceratocystis fimbriata growth of shoots, intensity of transpiration and the level of endogenous growth regulators were determined. More resistant clones, Populus 'Robusta' and P. 'PK-136-2' (P. nigra 'Italica': x P. laurifolia had more intensive growth of shoots, higher water content in leaves and a lower intensity of transpiration than the more susceptible clone, - P. 'NE-42' (P. maximowiczi x P. trichocarpa. The leaves of the more resistant clones contained more auxins (IAA and cytokinins, especially zeatin, and less growth inhibitors (ABA than those of the susceptible one. The level of plant growth regulators and/or the relations betweeen them may be responsible for the different poplar resistance to C. fimbriata.

  5. Identification of Quantitative Trait Loci (QTL) and Candidate Genes for Cadmium Tolerance in Populus

    Energy Technology Data Exchange (ETDEWEB)

    Induri, Brahma R [West Virginia University; Ellis, Danielle R [West Virginia University; Slavov, Gancho [West Virginia University; Yin, Tongming [ORNL; Muchero, Wellington [ORNL; Tuskan, Gerald A [ORNL; DiFazio, Stephen P [West Virginia University

    2012-01-01

    Knowledge of genetic variation in response of Populus to heavy metals like cadmium (Cd) is an important step in understanding the underlying mechanisms of tolerance. In this study, a pseudo-backcross pedigree of Populus trichocarpa and Populus deltoides was characterized for Cd exposure. The pedigree showed significant variation for Cd tolerance thus enabling the identification of relatively tolerant and susceptible genotypes for intensive characterization. A total of 16 QTLs at logarithm of odds (LOD) ratio > 2.5, were found to be associated with total dry weight, its components, and root volume. Four major QTLs for total dry weight were mapped to different linkage groups in control (LG III) and Cd conditions (LG XVI) and had opposite allelic effects on Cd tolerance, suggesting that these genomic regions were differentially controlled. The phenotypic variation explained by Cd QTL for all traits under study varied from 5.9% to 11.6% and averaged 8.2% across all QTL. Leaf Cd contents also showed significant variation suggesting the phytoextraction potential of Populus genotypes, though heritability of this trait was low (0.22). A whole-genome microarray study was conducted by using two genotypes with extreme responses for Cd tolerance in the above study and differentially expressed genes were identified. Candidate genes including CAD2 (CADMIUM SENSITIVE 2), HMA5 (HEAVY METAL ATPase5), ATGTST1 (Arabidopsis thaliana Glutathione S-Transferase1), ATGPX6 (Glutathione peroxidase 6), and ATMRP 14 (Arabidopsis thaliana Multidrug Resistance associated Protein 14) were identified from QTL intervals and microarray study. Functional characterization of these candidate genes could enhance phytoremediation capabilities of Populus.

  6. Genome Sequences of Populus tremula Chloroplast and Mitochondrion: Implications for Holistic Poplar Breeding.

    Directory of Open Access Journals (Sweden)

    Birgit Kersten

    Full Text Available Complete Populus genome sequences are available for the nucleus (P. trichocarpa; section Tacamahaca and for chloroplasts (seven species, but not for mitochondria. Here, we provide the complete genome sequences of the chloroplast and the mitochondrion for the clones P. tremula W52 and P. tremula x P. alba 717-1B4 (section Populus. The organization of the chloroplast genomes of both Populus clones is described. A phylogenetic tree constructed from all available complete chloroplast DNA sequences of Populus was not congruent with the assignment of the related species to different Populus sections. In total, 3,024 variable nucleotide positions were identified among all compared Populus chloroplast DNA sequences. The 5-prime part of the LSC from trnH to atpA showed the highest frequency of variations. The variable positions included 163 positions with SNPs allowing for differentiating the two clones with P. tremula chloroplast genomes (W52, 717-1B4 from the other seven Populus individuals. These potential P. tremula-specific SNPs were displayed as a whole-plastome barcode on the P. tremula W52 chloroplast DNA sequence. Three of these SNPs and one InDel in the trnH-psbA linker were successfully validated by Sanger sequencing in an extended set of Populus individuals. The complete mitochondrial genome sequence of P. tremula is the first in the family of Salicaceae. The mitochondrial genomes of the two clones are 783,442 bp (W52 and 783,513 bp (717-1B4 in size, structurally very similar and organized as single circles. DNA sequence regions with high similarity to the W52 chloroplast sequence account for about 2% of the W52 mitochondrial genome. The mean SNP frequency was found to be nearly six fold higher in the chloroplast than in the mitochondrial genome when comparing 717-1B4 with W52. The availability of the genomic information of all three DNA-containing cell organelles will allow a holistic approach in poplar molecular breeding in the future.

  7. Growth of Populus and Salix Species under Compost Leachate Irrigation

    Directory of Open Access Journals (Sweden)

    Tooba Abedi

    2014-12-01

    Full Text Available According to the known broad variation in remediation capacity, three plant species were used in the experiment: two fast growing poplar’s clones - Populus deltoides, Populus euramericana, and willows Salix alba. Populus and Salix cuttings were collected from the nursery of the Populus Research Center of Safrabasteh in the eastern part of Guilan province at north of Iran. The Populus clones were chosen because of their high biomass production capacity and willow- because it is native in Iran. The highest diameter growth rate was exhibited for all three plant species by the 1:1 treatment with an average of 0.26, 0.22 and 0.16 cm in eight months period for P. euroamericana, P. deltoides and S. alba, respectively. Over a period of eight months a higher growth rate of height was observed in (P and (1:1 treatment for S. alba (33.70 and 15.77 cm, respectively and in (C treatment for P. deltoides (16.51 cm. P. deltoides and S. alba produced significantly (p<0.05 smaller aboveground biomass in (P treatment compared to all species. P. deltoides exhibited greater mean aboveground biomass in the (1:1 treatment compared to other species. There were significant differences (p<0.05 in the growth of roots between P. deltoides, P. euramericana and S. alba in all of the treatments.

  8. Spatial distribution of leaf morphological and physiological characteristics in relation to local radiation regime within the canopies of 3-year-old Populus clones in coppice culture.

    Science.gov (United States)

    Casella, E; Ceulemans, R

    2002-12-01

    Spatial distributions of leaf characteristics relevant to photosynthesis were compared within high-density coppice canopies of Populus spp. of contrasting genetic origin. We studied three clones representative of the range in growth potential, leaf morphology, coppice and canopy structure: Clone Hoogvorst (Hoo) (Populus trichocarpa Torr. & Gray x Populus deltoides Bartr. & Marsh), Clone Fritzi Pauley (Fri) (Populus trichocarpa Torr. & Gray) and Clone Wolterson (Wol) (Populus nigra L.). Leaf area index ranged from 2.7 (Fri and Wol) to 3.8 (Hoo). The clones exhibited large vertical variation in leaf area density (0.02-1.42 m2 m-3). Leaf dry mass per unit leaf area (DM(A)) increased with increasing light in Clones Hoo and Fri, from about 56 g m-2 at the bottom of the canopy to 162 g m-2 at the top. In Clone Wol, DM(A) varied only from 65 to 100 g m-2, with no consistent relationship with respect to light. Conversely, nitrogen concentration on a mass basis was nearly constant (around 1.3-2.1%) within the canopies of Clones Hoo and Fri, but increased strongly with light in Clone Wol, from 1.4% at the bottom of the canopy to 4.1% at the top. As a result, nitrogen per unit leaf area (N(A)) increased with light in the canopies of all clones, from 0.9 g m-2 at the bottom to 2.9 g m-2 at the top. Although a single linear relationship described the dependence of maximum carboxylation rate (17-93 micromol CO2 m-2 s-1) or electron transport capacity (45-186 micromol electrons m-2 s-1) on N(A), for all clones, Clone Wol differed from Clones Hoo and Fri by exhibiting a higher dark respiration rate at low N(A) (1.8 versus 0.8 micromol CO2 m-2 s-1).

  9. Populus (Salicaceae plantations

    Directory of Open Access Journals (Sweden)

    Gonzalo M. Romano

    2013-01-01

    Full Text Available Aunque los cultivos forestales son comunidades artificiales, modifican condiciones ambientales que pueden alterar la diversidad fúngica nativa. Se estudiaron los efectos del manejo forestal de una plantación de sauces (Salix y álamos (Populus sobre la biodiversidad de Agaromycetes durante un año en una isla del Delta del Paraná, Argentina. Se midieron el peso seco y el número de basidiomas. Se identificaron 28 especies pertenecientes a los Agaricomycetes: 26 especies de Agaricales, una de Polyporales y una de Russulales. Nuestros resultados sugieren que el manejo forestal de dicha plantación no afecta la abundancia ni la diversidad de basidiomas de Agaricomycetes.

  10. Exploration of plant genomes in the FLAGdb++ environment

    Directory of Open Access Journals (Sweden)

    Leplé Jean-Charles

    2011-03-01

    Full Text Available Abstract Background In the contexts of genomics, post-genomics and systems biology approaches, data integration presents a major concern. Databases provide crucial solutions: they store, organize and allow information to be queried, they enhance the visibility of newly produced data by comparing them with previously published results, and facilitate the exploration and development of both existing hypotheses and new ideas. Results The FLAGdb++ information system was developed with the aim of using whole plant genomes as physical references in order to gather and merge available genomic data from in silico or experimental approaches. Available through a JAVA application, original interfaces and tools assist the functional study of plant genes by considering them in their specific context: chromosome, gene family, orthology group, co-expression cluster and functional network. FLAGdb++ is mainly dedicated to the exploration of large gene groups in order to decipher functional connections, to highlight shared or specific structural or functional features, and to facilitate translational tasks between plant species (Arabidopsis thaliana, Oryza sativa, Populus trichocarpa and Vitis vinifera. Conclusion Combining original data with the output of experts and graphical displays that differ from classical plant genome browsers, FLAGdb++ presents a powerful complementary tool for exploring plant genomes and exploiting structural and functional resources, without the need for computer programming knowledge. First launched in 2002, a 15th version of FLAGdb++ is now available and comprises four model plant genomes and over eight million genomic features.

  11. The Populus Genome Integrative Explorer (PopGenIE): a new resource for exploring the Populus genome.

    Science.gov (United States)

    Sjödin, Andreas; Street, Nathaniel Robert; Sandberg, Göran; Gustafsson, Petter; Jansson, Stefan

    2009-06-01

    Populus has become an important model plant system. However, utilization of the increasingly extensive collection of genetics and genomics data created by the community is currently hindered by the lack of a central resource, such as a model organism database (MOD). Such MODs offer a single entry point to the collection of resources available within a model system, typically including tools for exploring and querying those resources. As a starting point to overcoming the lack of such an MOD for Populus, we present the Populus Genome Integrative Explorer (PopGenIE), an integrated set of tools for exploring the Populus genome and transcriptome. The resource includes genome, synteny and quantitative trait locus (QTL) browsers for exploring genetic data. Expression tools include an electronic fluorescent pictograph (eFP) browser, expression profile plots, co-regulation within collated transcriptomics data sets, and identification of over-represented functional categories and genomic hotspot locations. A number of collated transcriptomics data sets are made available in the eFP browser to facilitate functional exploration of gene function. Additional homology and data extraction tools are provided. PopGenIE significantly increases accessibility to Populus genomics resources and allows exploration of transcriptomics data without the need to learn or understand complex statistical analysis methods. PopGenIE is available at www.popgenie.org or via www.populusgenome.info.

  12. Evaluation of two hybrid poplar clones as constructed wetland plant species for treating saline water high in boron and selenium, or waters only high in boron

    Science.gov (United States)

    Wetland mesocosms were constructed to assess two salt- and B-tolerant hybrid poplar clones (Populus trichocarpa ×P. deltoides×P. nigra '345-1' and '347-14') for treating saline water high in boron (B) and selenium (Se). In addition, a hydroponic experiment was performed to test the B tolerance and B...

  13. ADVANCE IN RESEARCH ON DROUGHT RESISTANCE OF POPULUS%杨树抗旱性研究进展

    Institute of Scientific and Technical Information of China (English)

    尹春英; 李春阳

    2003-01-01

    The drought resistance of woody plants, in particular, Populus, was reviewed in this paper. Studies about drought resistance of Populus mostly focused on changes in growth properties, physiological adaptation and biochemical aspects, but a few on molecular biology. The indexes of drought adaptation and productivity were analyzed and these indexes could be employed to identify drought resistance of woody plants. Combination of such different approaches will, hopefully, give us a more complete understanding of the various regulatory mechanisms in trees than what we may have today. With development of the molecular biology of woody plants, the sluties on stress resistance of Populus which was regarded as a model plant, are summarised. Ref 96

  14. Shipping coal to Newcastle: are SRIC populus plantations a viable fiber production option for the central hardwoods region?

    Science.gov (United States)

    C.H. Strauss

    1991-01-01

    Production costs for short rotation, intensive culture (SRIC) Populus biomass were developed from commercial-sized plantations under investigation throughout the eastern U.S. Populus hybrid planted on good quality plantation sites at a density of 850 cuttings/acre was projected to yield an average of 7 ovendry (OD) tons/acre/year....

  15. Stress-responsive hydroxycinnamate glycosyltransferase modulates phenylpropanoid metabolism in Populus

    OpenAIRE

    2014-01-01

    The diversity of phenylpropanoids offers a rich inventory of bioactive chemicals that can be exploited for plant improvement and human health. Recent evidence suggests that glycosylation may play a role in the partitioning of phenylpropanoid precursors for a variety of downstream uses. This work reports the functional characterization of a stress-responsive glycosyltransferase, GT1-316 in Populus. GT1-316 belongs to the UGT84A subfamily of plant glycosyltransferase family 1 and is designated ...

  16. Initial characterization of shade avoidance response suggests functional diversity between Populus phytochrome B genes.

    Energy Technology Data Exchange (ETDEWEB)

    Karve, Abhijit A [ORNL; Weston, David [ORNL; Jawdy, Sara [ORNL; Gunter, Lee E [ORNL; Allen, Sara M [ORNL; Yang, Xiaohan [ORNL; Wullschleger, Stan D [ORNL; Tuskan, Gerald A [ORNL

    2012-01-01

    Shade avoidance signaling in higher plants involves perception of the incident red/far-red (R/FR) light by phytochromes and the modulation of downstream transcriptional networks to regulate developmental plasticity in relation to heterogeneous light environments. In this study, we characterized the expression and functional features of Populus phytochrome (PHY) gene family as well as the transcriptional responses of Populus to the changes in R/FR light. Expression data indicated that PHYA is the predominant PHY in the dark grown Populus seedling whereas PHYBs are most abundant in mature tissue types. Out of three Populus PHYs, PHYA is light labile and localized to cytosol in dark whereas both PHYB1 and PHYB2 are light stable and are localized to nucleus in mesophyll protoplasts. When expressed in Arabidopsis, PHYB1 rescued Arabidopsis phyB mutant phenotype whereas PHYB2 did not, suggesting functional diversification between these two gene family members. However, phenotypes of transgenic Populus lines with altered expression of PHYB1, PHYB2 or both and the expression of candidate shade response genes in these transgenic lines suggest that PHYB1 and PHYB2 may have distinct yet overlapping functions. The RNAseq results and analysis of Populus exposed to enriched-FR light indicate that genes associated in cell wall modification and brassinosteroid signaling were induced under far red light. Overall our data indicate that Populus transcriptional responses are at least partially conserved with Arabidopsis.

  17. Species-specific expansion and molecular evolution of the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR gene family in plants.

    Directory of Open Access Journals (Sweden)

    Wei Li

    Full Text Available The terpene compounds represent the largest and most diverse class of plant secondary metabolites which are important in plant growth and development. The 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR; EC 1.1.1.34 is one of the key enzymes contributed to terpene biosynthesis. To better understand the basic characteristics and evolutionary history of the HMGR gene family in plants, a genome-wide analysis of HMGR genes from 20 representative species was carried out. A total of 56 HMGR genes in the 14 land plant genomes were identified, but no genes were found in all 6 algal genomes. The gene structure and protein architecture of all plant HMGR genes were highly conserved. The phylogenetic analysis revealed that the plant HMGRs were derived from one ancestor gene and finally developed into four distinct groups, two in the monocot plants and two in dicot plants. Species-specific gene duplications, caused mainly by segmental duplication, led to the limited expansion of HMGR genes in Zea mays, Gossypium raimondii, Populus trichocarpa and Glycine max after the species diverged. The analysis of Ka/Ks ratios and expression profiles indicated that functional divergence after the gene duplications was restricted. The results suggested that the function and evolution of HMGR gene family were dramatically conserved throughout the plant kingdom.

  18. Functional Gene Discovery and Characterization of Genes and Alleles Affecting Wood Biomass Yield and Quality in Populus

    Energy Technology Data Exchange (ETDEWEB)

    Busov, Victor [Michigan Technological Univ., Houghton, MI (United States)

    2017-02-12

    Adoption of biofuels as economically and environmentally viable alternative to fossil fuels would require development of specialized bioenergy varieties. A major goal in the breeding of such varieties is the improvement of lignocellulosic biomass yield and quality. These are complex traits and understanding the underpinning molecular mechanism can assist and accelerate their improvement. This is particularly important for tree bioenergy crops like poplars (species and hybrids from the genus Populus), for which breeding progress is extremely slow due to long generation cycles. A variety of approaches have been already undertaken to better understand the molecular bases of biomass yield and quality in poplar. An obvious void in these undertakings has been the application of mutagenesis. Mutagenesis has been instrumental in the discovery and characterization of many plant traits including such that affect biomass yield and quality. In this proposal we use activation tagging to discover genes that can significantly affect biomass associated traits directly in poplar, a premier bioenergy crop. We screened a population of 5,000 independent poplar activation tagging lines under greenhouse conditions for a battery of biomass yield traits. These same plants were then analyzed for changes in wood chemistry using pyMBMS. As a result of these screens we have identified nearly 800 mutants, which are significantly (P<0.05) different when compared to wild type. Of these majority (~700) are affected in one of ten different biomass yield traits and 100 in biomass quality traits (e.g., lignin, S/G ration and C6/C5 sugars). We successfully recovered the position of the tag in approximately 130 lines, showed activation in nearly half of them and performed recapitulation experiments with 20 genes prioritized by the significance of the phenotype. Recapitulation experiments are still ongoing for many of the genes but the results are encouraging. For example, we have shown successful

  19. Towards a map of the Populus biomass protein-protein interaction network

    Energy Technology Data Exchange (ETDEWEB)

    Beers, Eric [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Brunner, Amy [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Helm, Richard [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Dickerman, Allan [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    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

  20. Efficient Agrobacterium-Mediated Transformation of Hybrid Poplar Populus davidiana Dode × Populus bollena Lauche

    Directory of Open Access Journals (Sweden)

    Xue Han

    2013-01-01

    Full Text Available Poplar is a model organism for high in vitro regeneration in woody plants. We have chosen a hybrid poplar Populus davidiana Dode × Populus bollena Lauche. By optimizing the Murashige and Skoog medium with (0.3 mg/L 6-benzylaminopurine and (0.08 mg/L naphthaleneacetic acid, we have achieved the highest frequency (90% for shoot regeneration from poplar leaves. It was also important to improve the transformation efficiency of poplar for genetic breeding and other applications. In this study, we found a significant improvement of the transformation frequency by controlling the leaf age. Transformation efficiency was enhanced by optimizing the Agrobacterium concentration (OD600 = 0.8–1.0 and an infection time (20–30 min. According to transmission electron microscopy observations, there were more Agrobacterium invasions in the 30-day-old leaf explants than in 60-day-old and 90-day-old explants. Using the green fluorescent protein (GFP marker, the expression of MD–GFP fusion proteins in the leaf, shoot, and root of hybrid poplar P. davidiana Dode × P. bollena Lauche was visualized for confirmation of transgene integration. Southern and Northern blot analysis also showed the integration of T-DNA into the genome and gene expression of transgenic plants. Our results suggest that younger leaves had higher transformation efficiency (~30% than older leaves (10%.

  1. A census of nuclear cyanobacterial recruits in the plant kingdom.

    Directory of Open Access Journals (Sweden)

    Szabolcs Makai

    Full Text Available The plastids and mitochondria of the eukaryotic cell are of endosymbiotic origin. These events occurred ~2 billion years ago and produced significant changes in the genomes of the host and the endosymbiont. Previous studies demonstrated that the invasion of land affected plastids and mitochondria differently and that the paths of mitochondrial integration differed between animals and plants. Other studies examined the reasons why a set of proteins remained encoded in the organelles and were not transferred to the nuclear genome. However, our understanding of the functional relations of the transferred genes is insufficient. In this paper, we report a high-throughput phylogenetic analysis to identify genes of cyanobacterial origin for plants of different levels of complexity: Arabidopsis thaliana, Chlamydomonas reinhardtii, Physcomitrella patens, Populus trichocarpa, Selaginella moellendorffii, Sorghum bicolor, Oryza sativa, and Ostreococcus tauri. Thus, a census of cyanobacterial gene recruits and a study of their function are presented to better understand the functional aspects of plastid symbiogenesis. From algae to angiosperms, the GO terms demonstrated a gradual expansion over functionally related genes in the nuclear genome, beginning with genes related to thylakoids and photosynthesis, followed by genes involved in metabolism, and finally with regulation-related genes, primarily in angiosperms. The results demonstrate that DNA is supplied to the nuclear genome on a permanent basis with no regard to function, and only what is needed is kept, which thereby expands on the GO space along the related genes.

  2. Prototype wood chunker used on Populus 'Tristis'

    Science.gov (United States)

    Rodger A. Arola; Roger C. Radcliffe; Sharon A. Winsauer

    1983-01-01

    Populus 'Tristis' trees grown under short-rotation, intensive culture were sampled and chunked in a prototype experimental wood chunking machine. Data presented describe the character of the trees chunked, the energy and power requirements for chunking, and the chunking rates Specific energy requirements for chunking Populus 'Tristis...

  3. Identification of shared single copy nuclear genes in Arabidopsis, Populus, Vitis and Oryza and their phylogenetic utility across various taxonomic levels

    Directory of Open Access Journals (Sweden)

    Ma Hong

    2010-02-01

    Full Text Available Abstract Background Although the overwhelming majority of genes found in angiosperms are members of gene families, and both gene- and genome-duplication are pervasive forces in plant genomes, some genes are sufficiently distinct from all other genes in a genome that they can be operationally defined as 'single copy'. Using the gene clustering algorithm MCL-tribe, we have identified a set of 959 single copy genes that are shared single copy genes in the genomes of Arabidopsis thaliana, Populus trichocarpa, Vitis vinifera and Oryza sativa. To characterize these genes, we have performed a number of analyses examining GO annotations, coding sequence length, number of exons, number of domains, presence in distant lineages, such as Selaginella and Physcomitrella, and phylogenetic analysis to estimate copy number in other seed plants and to demonstrate their phylogenetic utility. We then provide examples of how these genes may be used in phylogenetic analyses to reconstruct organismal history, both by using extant coverage in EST databases for seed plants and de novo amplification via RT-PCR in the family Brassicaceae. Results There are 959 single copy nuclear genes shared in Arabidopsis, Populus, Vitis and Oryza ["APVO SSC genes"]. The majority of these genes are also present in the Selaginella and Physcomitrella genomes. Public EST sets for 197 species suggest that most of these genes are present across a diverse collection of seed plants, and appear to exist as single or very low copy genes, though exceptions are seen in recently polyploid taxa and in lineages where there is significant evidence for a shared large-scale duplication event. Genes encoding proteins localized in organelles are more commonly single copy than expected by chance, but the evolutionary forces responsible for this bias are unknown. Regardless of the evolutionary mechanisms responsible for the large number of shared single copy genes in diverse flowering plant lineages, these

  4. Identification of shared single copy nuclear genes in Arabidopsis, Populus, Vitis and Oryza and their phylogenetic utility across various taxonomic levels

    Science.gov (United States)

    2010-01-01

    Background Although the overwhelming majority of genes found in angiosperms are members of gene families, and both gene- and genome-duplication are pervasive forces in plant genomes, some genes are sufficiently distinct from all other genes in a genome that they can be operationally defined as 'single copy'. Using the gene clustering algorithm MCL-tribe, we have identified a set of 959 single copy genes that are shared single copy genes in the genomes of Arabidopsis thaliana, Populus trichocarpa, Vitis vinifera and Oryza sativa. To characterize these genes, we have performed a number of analyses examining GO annotations, coding sequence length, number of exons, number of domains, presence in distant lineages, such as Selaginella and Physcomitrella, and phylogenetic analysis to estimate copy number in other seed plants and to demonstrate their phylogenetic utility. We then provide examples of how these genes may be used in phylogenetic analyses to reconstruct organismal history, both by using extant coverage in EST databases for seed plants and de novo amplification via RT-PCR in the family Brassicaceae. Results There are 959 single copy nuclear genes shared in Arabidopsis, Populus, Vitis and Oryza ["APVO SSC genes"]. The majority of these genes are also present in the Selaginella and Physcomitrella genomes. Public EST sets for 197 species suggest that most of these genes are present across a diverse collection of seed plants, and appear to exist as single or very low copy genes, though exceptions are seen in recently polyploid taxa and in lineages where there is significant evidence for a shared large-scale duplication event. Genes encoding proteins localized in organelles are more commonly single copy than expected by chance, but the evolutionary forces responsible for this bias are unknown. Regardless of the evolutionary mechanisms responsible for the large number of shared single copy genes in diverse flowering plant lineages, these genes are valuable for

  5. Acetylesterase-Mediated Deacetylation of Pectin Impairs Cell Elongation, Pollen Germination, and Plant Reproduction

    Energy Technology Data Exchange (ETDEWEB)

    Gou J. Y.; Liu C.; Miller, L. M.; Hou, G.; Yu, X.-H.; Chen, X.-Y.

    2012-01-01

    Pectin is a major component of the primary cell wall of higher plants. Some galacturonyl residues in the backbone of pectinaceous polysaccharides are often O-acetylated at the C-2 or C-3 position, and the resulting acetylesters change dynamically during the growth and development of plants. The processes involve both enzymatic acetylation and deacetylation. Through genomic sequence analysis, we identified a pectin acetylesterase (PAE1) from black cottonwood (Populus trichocarpa). Recombinant Pt PAE1 exhibited preferential activity in releasing the acetate moiety from sugar beet (Beta vulgaris) and potato (Solanum tuberosum) pectin in vitro. Overexpressing Pt PAE1 in tobacco (Nicotiana tabacum) decreased the level of acetyl esters of pectin but not of xylan. Deacetylation engendered differential changes in the composition and/or structure of cell wall polysaccharides that subsequently impaired the cellular elongation of floral styles and filaments, the germination of pollen grains, and the growth of pollen tubes. Consequently, plants overexpressing PAE1 exhibited severe male sterility. Furthermore, in contrast to the conventional view, PAE1-mediated deacetylation substantially lowered the digestibility of pectin. Our data suggest that pectin acetylesterase functions as an important structural regulator in planta by modulating the precise status of pectin acetylation to affect the remodeling and physiochemical properties of the cell wall's polysaccharides, thereby affecting cell extensibility.

  6. Gender determination in populus

    Energy Technology Data Exchange (ETDEWEB)

    McLetchie, D.N. [Univ. of Kentucky, Lexington, KY (United States). Dept. of Biological Sciences; Tuskan, G.A. [Oak Ridge National Lab., TN (United States)

    1994-12-31

    Gender, the expression of maleness or femaleness, in dioecious plants has been associated with changes in morphology, physiology, ecological position, and commercial importance of several species, including members of the Salicaceae family. Various mechanisms have been proposed to explain the expression of gender in Salicaceae, including sex chromosomes, simple Mendelian genes, quantitative genes, environment, and genotype-by-environment interactions. Published reports would favor a genetic basis for gender. The objective of this study was to identify molecular markers associated with gender in a segregating family of hybrid poplars. Bulked segregant analysis and chi-squared analysis were used to test for the occurrence of sex chromosomes, individual loci, and chromosome ratios (i.e., ploidy levels) as the mechanisms for gender determination. Examination of 2488 PCR based RAPD markers from 1219 primers revealed nine polymorphic bands between male and female bulked samples. However, linkage analysis indicated that none of these markers were significantly associated with gender. Chisquared results for difference in male-to-female ratios between diploid and triploid genotypes also revealed no significant differences. These findings suggest gender is not controlled via sex chromosomes, simple Mendelian loci or ratios of autosome to gender-determining loci. It is possible that gender is determined genetically by regions of the genome not sampled by the tested markers or by a complex of loci operating in an additive threshold manner or in an epistatic manner. It is also possible that gender is determined environmentally at an early zygote stage, canalizing gender expression.

  7. Using Populus as a lignocellulosic feedstock for bioethanol.

    Science.gov (United States)

    Porth, Ilga; El-Kassaby, Yousry A

    2015-04-01

    Populus species along with species from the sister genus Salix will provide valuable feedstock resources for advanced second-generation biofuels. Their inherent fast growth characteristics can particularly be exploited for short rotation management, a time and energy saving cultivation alternative for lignocellulosic feedstock supply. Salicaceae possess inherent cell wall characteristics with favorable cellulose to lignin ratios for utilization as bioethanol crop. We review economically important traits relevant for intensively managed biofuel crop plantations, genomic and phenotypic resources available for Populus, breeding strategies for forest trees dedicated to bioenergy provision, and bioprocesses and downstream applications related to opportunities using Salicaceae as a renewable resource. Challenges need to be resolved for every single step of the conversion process chain, i.e., starting from tree domestication for improved performance as a bioenergy crop, bioconversion process, policy development for land use changes associated with advanced biofuels, and harvest and supply logistics associated with industrial-scale biorefinery plants using Populus as feedstock. Significant hurdles towards cost and energy efficiency, environmental friendliness, and yield maximization with regards to biomass pretreatment, saccharification, and fermentation of celluloses and the sustainability of biorefineries as a whole still need to be overcome.

  8. Genome-wide identification of lineage-specific genes in Arabidopsis, Oryza and Populus

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaohan [ORNL; Jawdy, Sara [ORNL; Tschaplinski, Timothy J [ORNL; Tuskan, Gerald A [ORNL

    2009-01-01

    Protein sequences were compared among Arabidopsis, Oryza and Populus to identify differential gene (DG) sets that are in one but not the other two genomes. The DG sets were screened against a plant transcript database, the NR protein database and six newly-sequenced genomes (Carica, Glycine, Medicago, Sorghum, Vitis and Zea) to identify a set of species-specific genes (SS). Gene expression, protein motif and intron number were examined. 192, 641 and 109 SS genes were identified in Arabidopsis, Oryza and Populus, respectively. Some SS genes were preferentially expressed in flowers, roots, xylem and cambium or up-regulated by stress. Six conserved motifs in Arabidopsis and Oryza SS proteins were found in other distant lineages. The SS gene sets were enriched with intronless genes. The results reflect functional and/or anatomical differences between monocots and eudicots or between herbaceous and woody plants. The Populus-specific genes are candidates for carbon sequestration and biofuel research.

  9. PlnTFDB: an integrative plant transcription factor database

    Directory of Open Access Journals (Sweden)

    Ruzicic Slobodan

    2007-02-01

    Full Text Available Abstract Background Transcription factors (TFs are key regulatory proteins that enhance or repress the transcriptional rate of their target genes by binding to specific promoter regions (i.e. cis-acting elements upon activation or de-activation of upstream signaling cascades. TFs thus constitute master control elements of dynamic transcriptional networks. TFs have fundamental roles in almost all biological processes (development, growth and response to environmental factors and it is assumed that they play immensely important functions in the evolution of species. In plants, TFs have been employed to manipulate various types of metabolic, developmental and stress response pathways. Cross-species comparison and identification of regulatory modules and hence TFs is thought to become increasingly important for the rational design of new plant biomass. Up to now, however, no computational repository is available that provides access to the largely complete sets of transcription factors of sequenced plant genomes. Description PlnTFDB is an integrative plant transcription factor database that provides a web interface to access large (close to complete sets of transcription factors of several plant species, currently encompassing Arabidopsis thaliana (thale cress, Populus trichocarpa (poplar, Oryza sativa (rice, Chlamydomonas reinhardtii and Ostreococcus tauri. It also provides an access point to its daughter databases of a species-centered representation of transcription factors (OstreoTFDB, ChlamyTFDB, ArabTFDB, PoplarTFDB and RiceTFDB. Information including protein sequences, coding regions, genomic sequences, expressed sequence tags (ESTs, domain architecture and scientific literature is provided for each family. Conclusion We have created lists of putatively complete sets of transcription factors and other transcriptional regulators for five plant genomes. They are publicly available through http://plntfdb.bio.uni-potsdam.de. Further data will be

  10. Clone history shapes Populus drought responses.

    Science.gov (United States)

    Raj, Sherosha; Bräutigam, Katharina; Hamanishi, Erin T; Wilkins, Olivia; Thomas, Barb R; Schroeder, William; Mansfield, Shawn D; Plant, Aine L; Campbell, Malcolm M

    2011-07-26

    Just as animal monozygotic twins can experience different environmental conditions by being reared apart, individual genetically identical trees of the genus Populus can also be exposed to contrasting environmental conditions by being grown in different locations. As such, clonally propagated Populus trees provide an opportunity to interrogate the impact of individual environmental history on current response to environmental stimuli. To test the hypothesis that current responses to an environmental stimulus, drought, are contingent on environmental history, the transcriptome- level drought responses of three economically important hybrid genotypes-DN34 (Populus deltoides × Populus nigra), Walker [P. deltoides var. occidentalis × (Populus laurifolia × P. nigra)], and Okanese [Walker × (P. laurifolia × P. nigra)]-derived from two different locations were compared. Strikingly, differences in transcript abundance patterns in response to drought were based on differences in geographic origin of clones for two of the three genotypes. This observation was most pronounced for the genotypes with the longest time since establishment and last common propagation. Differences in genome-wide DNA methylation paralleled the transcriptome level trends, whereby the clones with the most divergent transcriptomes and clone history had the most marked differences in the extent of total DNA methylation, suggesting an epigenomic basis for the clone history-dependent transcriptome divergence. The data provide insights into the interplay between genotype and environment in the ecologically and economically important Populus genus, with implications for the industrial application of Populus trees and the evolution and persistence of these important tree species and their associated hybrids.

  11. Moving Away from the Reference Genome: Evaluating a Peptide Sequencing Tagging Approach for Single Amino Acid Polymorphism Identifications in the Genus Populus

    Energy Technology Data Exchange (ETDEWEB)

    Abraham, Paul E [ORNL; Adams, Rachel M [ORNL; Tuskan, Gerald A [ORNL; Hettich, Robert {Bob} L [ORNL

    2013-01-01

    The genetic diversity across natural populations of the model organism, Populus, is extensive, containing a single nucleotide polymorphism roughly every 200 base pairs. When deviations from the reference genome occur in coding regions, they can impact protein sequences. Rather than relying on a static reference database to profile protein expression, we employed a peptide sequence tagging (PST) approach capable of decoding the plasticity of the Populus proteome. Using shotgun proteomics data from two genotypes of P. trichocarpa, a tag-based approach enabled the detection of 6,653 unexpected sequence variants. Through manual validation, our study investigated how the most abundant chemical modification (methionine oxidation) could masquerade as a sequence variant (AlaSer) when few site-determining ions existed. In fact, precise localization of an oxidation site for peptides with more than one potential placement was indeterminate for 70% of the MS/MS spectra. We demonstrate that additional fragment ions made available by high energy collisional dissociation enhances the robustness of the peptide sequence tagging approach (81% of oxidation events could be exclusively localized to a methionine). We are confident that augmenting fragmentation processes for a PST approach will further improve the identification of single amino acid polymorphism in Populus and potentially other species as well.

  12. Two Highly Similar Poplar Paleo-subgenomes Suggest an Autotetraploid Ancestor of Salicaceae Plants.

    Science.gov (United States)

    Liu, Yinzhe; Wang, Jinpeng; Ge, Weina; Wang, Zhenyi; Li, Yuxian; Yang, Nanshan; Sun, Sangrong; Zhang, Liwei; Wang, Xiyin

    2017-01-01

    As a model plant to study perennial trees in the Salicaceae family, the poplar (Populus trichocarpa) genome was sequenced, revealing recurrent paleo-polyploidizations during its evolution. A comparative and hierarchical alignment of its genome to a well-selected reference genome would help us better understand poplar's genome structure and gene family evolution. Here, by adopting the relatively simpler grape (Vitis vinifera) genome as reference, and by inferring both intra- and inter-genomic gene collinearity, we produced a united alignment of these two genomes and hierarchically distinguished the layers of paralogous and orthologous genes, as related to recursive polyploidizations and speciation. We uncovered homologous blocks in the grape and poplar genomes and also between them. Moreover, we characterized the genes missing and found that poplar had two considerably similar subgenomes (≤0.05 difference in gene deletion) produced by the Salicaceae-common tetraploidization, suggesting its autotetraploid nature. Taken together, this work provides a timely and valuable dataset of orthologous and paralogous genes for further study of the genome structure and functional evolution of poplar and other Salicaceae plants.

  13. Phylogenetic Analysis of K+ Transporters in Bryophytes, Lycophytes, and Flowering Plants Indicates a Specialization of Vascular Plants

    Science.gov (United States)

    Gomez-Porras, Judith Lucia; Riaño-Pachón, Diego Mauricio; Benito, Begoña; Haro, Rosario; Sklodowski, Kamil; Rodríguez-Navarro, Alonso; Dreyer, Ingo

    2012-01-01

    As heritage from early evolution, potassium (K+) is absolutely necessary for all living cells. It plays significant roles as stabilizer in metabolism and is important for enzyme activation, stabilization of protein synthesis, and neutralization of negative charges on cellular molecules as proteins and nucleic acids. Land plants even enlarged this spectrum of K+ utilization after having gone ashore, despite the fact that K+ is far less available in their new oligotrophic habitats than in sea water. Inevitably, plant cells had to improve and to develop unique transport systems for K+ accumulation and distribution. In the past two decades a manifold of K+ transporters from flowering plants has been identified at the molecular level. The recently published genome of the fern ally Selaginella moellendorffii now helps in providing a better understanding on the molecular changes involved in the colonization of land and the development of the vasculature and the seeds. In this article we present an inventory of K+ transporters of this lycophyte and pigeonhole them together with their relatives from the moss Physcomitrella patens, the monocotyledon Oryza sativa, and two dicotyledonous species, the herbaceous plant Arabidopsis thaliana, and the tree Populus trichocarpa. Interestingly, the transition of green plants from an aqueous to a dry environment coincides with a dramatic reduction in the diversity of voltage-gated potassium channels followed by a diversification on the basis of one surviving K+ channel class. The first appearance of K+ release (Kout) channels in S. moellendorffii that were shown in Arabidopsis to be involved in xylem loading and guard cell closure coincides with the specialization of vascular plants and may indicate an important adaptive step. PMID:22876252

  14. Above Ground Leafless Woody Biomass and Nutrient Content within Different Compartments of a P. maximowicii × P. trichocarpa Poplar Clone

    Directory of Open Access Journals (Sweden)

    Heinrich Spiecker

    2013-06-01

    Full Text Available In this study the quantification of biomass within all relevant compartments of a three-year-old poplar clone (P. maximowicii × P. trichocarpa planted on abandoned agricultural land at a density of 5000 trees ha−1 is presented. A total of 30 trees within a diameter range of 1.8 cm to 8.9 cm, at breast height (dbh at 1.3 m, were destructively sampled. In order to analyze the biomass, the complete tree, stem, as well as all branches, were divided into 1 cm diameter classes and all buds from the trees were completely removed. Total yield was calculated as 11.7 odt ha−1 year−1 (oven dry tonnes per hectare and year. Branches constituted 22.2% of total dry leafless biomass and buds 2.0%. The analyses revealed a strong correlation of the dry weight for all the three compartments with diameter at breast height. Debarked sample discs were used to obtain a ratio between wood and bark. Derived from these results, a model was developed to calculate the biomass of bark with dbh as the predictor variable. Mean bark percentage was found to be 16.8% of above ground leafless biomass. The results concur that bark percentage decreases with increasing tree diameter, providing the conclusion that larger trees contain a lower bark proportion, and thus positively influence the quality of the end product while consequently reducing the export of nutrients from site.

  15. Response of Populus x canescens (Populus tremula x alba) to high concentration of NaCl stress

    Institute of Scientific and Technical Information of China (English)

    GAO Jian; PENG Zhen-hua

    2006-01-01

    Populus x canescens was cultivated on solid substrate and treated by salt (150 mM NaCl). The growth parametersincluding new leaf formation, height increment, diameter at the base increment, fresh and dry mass of leaf, stem, coarse root, and fine root were determined. The nutrient elements in leaves of samples under salt stress and the control, and the chlorophyll fluorescence of plants separated dark and light, initial fluorescence (Fo), and maximum fluorescence (Fm) were measured. Results showed that 150 mM NaCl treatment resulted in growth reduction of Populus x canescens. Nutrient element contents in the foliage of plants under salt stress were different from that of control. The foliar N-concentrations of plants under salt stress were not affected. Contents of Na under salt stress were 120 times as much as that under control. However, contents of S, K, P, Ca, Mg, Fe, Mn under salt stress were less than that under control. Salt stress caused damage in the PSII reaction centers, i.e. photo-inhibition couldn't be repaired under dark situation. The yield of chlorophyll fluorescence showed that several parameters associated with PSII functions, e.g. Fv/Fo, Fv/Fm were not influenced at the first stage of salt stress treatment. However, after a period of time, PSII functions were significantly inhibited, which led to the decrease of carbon assimilation. These results suggest that salt stress (150 mM NaCl) did not affect photosynthetic chlorophyll fluorescence of Populus x canescens immediately. After four day of salt stress, PSII reaction centres were seriously damaged during photo-inhibition.

  16. Bioinformatic Identification and Analysis of Extensins in the Plant Kingdom

    Science.gov (United States)

    Liu, Xiao; Wolfe, Richard; Welch, Lonnie R.; Domozych, David S.; Popper, Zoë A.; Showalter, Allan M.

    2016-01-01

    Extensins (EXTs) are a family of plant cell wall hydroxyproline-rich glycoproteins (HRGPs) that are implicated to play important roles in plant growth, development, and defense. Structurally, EXTs are characterized by the repeated occurrence of serine (Ser) followed by three to five prolines (Pro) residues, which are hydroxylated as hydroxyproline (Hyp) and glycosylated. Some EXTs have Tyrosine (Tyr)-X-Tyr (where X can be any amino acid) motifs that are responsible for intramolecular or intermolecular cross-linkings. EXTs can be divided into several classes: classical EXTs, short EXTs, leucine-rich repeat extensins (LRXs), proline-rich extensin-like receptor kinases (PERKs), formin-homolog EXTs (FH EXTs), chimeric EXTs, and long chimeric EXTs. To guide future research on the EXTs and understand evolutionary history of EXTs in the plant kingdom, a bioinformatics study was conducted to identify and classify EXTs from 16 fully sequenced plant genomes, including Ostreococcus lucimarinus, Chlamydomonas reinhardtii, Volvox carteri, Klebsormidium flaccidum, Physcomitrella patens, Selaginella moellendorffii, Pinus taeda, Picea abies, Brachypodium distachyon, Zea mays, Oryza sativa, Glycine max, Medicago truncatula, Brassica rapa, Solanum lycopersicum, and Solanum tuberosum, to supplement data previously obtained from Arabidopsis thaliana and Populus trichocarpa. A total of 758 EXTs were newly identified, including 87 classical EXTs, 97 short EXTs, 61 LRXs, 75 PERKs, 54 FH EXTs, 38 long chimeric EXTs, and 346 other chimeric EXTs. Several notable findings were made: (1) classical EXTs were likely derived after the terrestrialization of plants; (2) LRXs, PERKs, and FHs were derived earlier than classical EXTs; (3) monocots have few classical EXTs; (4) Eudicots have the greatest number of classical EXTs and Tyr-X-Tyr cross-linking motifs are predominantly in classical EXTs; (5) green algae have no classical EXTs but have a number of long chimeric EXTs that are absent in

  17. Bioinformatic Identification and Analysis of Extensins in the Plant Kingdom.

    Directory of Open Access Journals (Sweden)

    Xiao Liu

    Full Text Available Extensins (EXTs are a family of plant cell wall hydroxyproline-rich glycoproteins (HRGPs that are implicated to play important roles in plant growth, development, and defense. Structurally, EXTs are characterized by the repeated occurrence of serine (Ser followed by three to five prolines (Pro residues, which are hydroxylated as hydroxyproline (Hyp and glycosylated. Some EXTs have Tyrosine (Tyr-X-Tyr (where X can be any amino acid motifs that are responsible for intramolecular or intermolecular cross-linkings. EXTs can be divided into several classes: classical EXTs, short EXTs, leucine-rich repeat extensins (LRXs, proline-rich extensin-like receptor kinases (PERKs, formin-homolog EXTs (FH EXTs, chimeric EXTs, and long chimeric EXTs. To guide future research on the EXTs and understand evolutionary history of EXTs in the plant kingdom, a bioinformatics study was conducted to identify and classify EXTs from 16 fully sequenced plant genomes, including Ostreococcus lucimarinus, Chlamydomonas reinhardtii, Volvox carteri, Klebsormidium flaccidum, Physcomitrella patens, Selaginella moellendorffii, Pinus taeda, Picea abies, Brachypodium distachyon, Zea mays, Oryza sativa, Glycine max, Medicago truncatula, Brassica rapa, Solanum lycopersicum, and Solanum tuberosum, to supplement data previously obtained from Arabidopsis thaliana and Populus trichocarpa. A total of 758 EXTs were newly identified, including 87 classical EXTs, 97 short EXTs, 61 LRXs, 75 PERKs, 54 FH EXTs, 38 long chimeric EXTs, and 346 other chimeric EXTs. Several notable findings were made: (1 classical EXTs were likely derived after the terrestrialization of plants; (2 LRXs, PERKs, and FHs were derived earlier than classical EXTs; (3 monocots have few classical EXTs; (4 Eudicots have the greatest number of classical EXTs and Tyr-X-Tyr cross-linking motifs are predominantly in classical EXTs; (5 green algae have no classical EXTs but have a number of long chimeric EXTs that are absent in

  18. Protein (Viridiplantae): 224115152 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 5294 3694:5294 predicted protein Populus trichocarpa MSYPKYRSVKVINNPARLIVGDDFRVNWDCLRLSIPTSAVEGVSLIISESSTTLLSVTITESIGTGLLPSQQGLCART...SKAAATLFSVTLTESTGNVRRDKSRHQLGKQFCDDYRVNRDCARVRNRASAGEAVSATISKAAATQFWVTITESTGITESTGIITESRRTGMCARTKPSFSWGSSFDD...NVRRDKSRFNWGSSSGGDFRVGRDSFSVMISESTETELCARTKPSFSWGSSFGNDFQVGSDFVFGDDYRVNSYYRVNRDSY

  19. Protein (Viridiplantae): 224137436 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 2832 predicted protein Populus trichocarpa MKGIRVRDLPRYARWKDPNDCVFNHNMESTEKACKASAIIVHSFDALEQEVLNALYSMFPRVYPI...RDPNDCLFNYTMESTEKACKASAIIVHSFDALEQEVLNALYSMFPRVYPIGPLQLLLNQVPEDDLNSIGCNLWKEEPECLQWLDSKKPNSVVYVNFGKSDDIIDKGMC

  20. Protein (Viridiplantae): 224111224 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 4:1369 predicted protein Populus trichocarpa MVRISRGIADMLISFDWHGLRQLPSLVELTIRRCPSLSHIPEDDCLGSLTQLKELIIGGFSEE...LEAFPAGLLNSIQLLNLSGSLKHLTIHGWDTLKSVPHQLQHLTALEKLWIIDFYGEEFEEALPEWLANLSSLQSLWISHCKNLKYLPSSTAIQRLSKLKELEISGCRHLKENCRKENGSEWPKISHIPEISIDLILVQVSWDLNFMSFNNNQ ...

  1. Protein (Viridiplantae): 224148846 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 791 3694:10791 predicted protein Populus trichocarpa MARIEIAFEKFSLLRIFQTWAGRPRELGPLKNLYVLRFLTLPPFSRTPSSAPLSPRFLPSSAPLSPRFPSSAPLSPRFLP...SSAPLSPRFPSSAPLSPRFLPSSAPLSPRFLPSSAPLSPRFPSSAPLSPRFLPSSAPLSPHFLPRAPLSPRFPL ...

  2. Protein (Viridiplantae): 224118952 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 4:7786 predicted protein Populus trichocarpa MLDRCLGTHRVRQIQRATRHGKITLLCLFMTVVVLRGTIGAGKSGTPEQDFNDLRNHIYASRK...HAEPHRVLTESNQSNNNKNDEGSNANDANNYAAFDINKILVDEGEDEKPDPNKPYFLGPKISDWDEQRAKWLSENPNFSNF

  3. Protein (Viridiplantae): 224129640 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 8070 predicted protein Populus trichocarpa MEAHHHHHQFTHNIFERRPIIRSKTPAVKWFKEWVPQDVVATGGRCSLFKWVTENQLNALKEKAKEPQAPEPEPEPTTEVLFLCSFEGCG...KTFIDAGALRKHSHIHGERQYVCHYEGCGKKFLDSSKLKRHFLIHTGERDFICPHEGCG

  4. Protein (Viridiplantae): 224127650 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available SKVAENSFIVVMLSKSKVSSGGPSTATAAPPNVSSGGPSTATAAPPTLVSAQPTSSLPSNVTQPSSTSQAAVPAAAFSDAD...redicted protein, partial Populus trichocarpa MKVFVKTLKGTNFEIEVKPEDTVVVEVKKNIENVQGADVYPAAQQMLIYQGKVLKDDTTLDE

  5. Protein (Viridiplantae): 224122422 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 3694:9513 predicted protein Populus trichocarpa MRMGSRGHQARAACAAPLPALLPTPEGLGQRHAHGPAFEPSLSPFERAFEPSLPFERAFEPSLSPFERAFQPSLPFE...RAFEPSLSPFERAFEPLLSPFELAFEPSLPFERAFEPSLSPFERAFQPSLPFERAFEPSLSPFERAFEPLLSPFELAFEPSLSPFERAFEPSLSLRARLSALAFSLRARL ...

  6. Protein (Viridiplantae): 224142529 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 3689:10587 3694:10587 predicted protein Populus trichocarpa MSDMSYKLSSPSTSNSGYTERELVGAKMSSLANAHDLSNMSYKLSSPSTSNGRYTERDLVGAEMSCLANAHD...LSDLSSKLSFPSTSNGRYTERGLVGAEMSCLANAHDLINLSSKLSFLSTSNGRYTERDLVGAKMSSRNPLHKYSTSASHSVHRSLASACPQSIRM ...

  7. Protein (Viridiplantae): 224144295 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 3689:10587 3694:10587 predicted protein Populus trichocarpa MSDMSYKLSSPSTSNSGYTERELVGAKMSCLANAHDLSNMSYKLSSPSTSNGRYTERDLVGAEMSCLANAHD...LSDLSSKLSFPSTSNGRYTERGLVGAEMSCLANAHDLINLSSKLSFLSTSNGRYTERDLVGAKMSSRNPLHKYSTSTSHSVHRSLASACPQSIRM ...

  8. Protein (Viridiplantae): 224142533 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 3689:10587 3694:10587 predicted protein Populus trichocarpa MSSPANAHDLRNLSSKLSFPSTSNGRYAERDLVGAKMSSPANAHNLR...NLSSKLSFPSTSNGRYAERDLVGAKMSSPANAHDLRNLSSKLSFPSTSSSRYAERDLVGAKMSSPANAHDLRNFSFPSTSNGRYAERDLVGA ...

  9. Protein (Viridiplantae): 224106471 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 3694:8508 predicted protein, partial Populus trichocarpa MSGVWIFDKNGVARLITNPTRESFEQKEPLHPGTATAPGARPRVLVYLPANHVIRSYTELEQRLAELGWTRYYNSNQPNLLQFHKSDNSAHLISLPRDFDSFKPLHMYDIVVKNRSFFEVRD ...

  10. Protein (Viridiplantae): 224072389 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available NRDQERKKEADRAYRQRCKFKKIKNEEKLCALTEENNRLDRENKHLKNEEVRLKEVVQTQNENMKQLQGHFCQLKSQLDKQ...694:1072 predicted protein Populus trichocarpa MWPPELATTSTANEIGGSYEINTVPSMIQPPIEQYMSFLSGCLDSPTIPDSKQKRKAPDDV

  11. Differential expression profiles of poplar MAP kinase kinases in response to abiotic stresses and plant hormones, and overexpression of PtMKK4 improves the drought tolerance of poplar.

    Science.gov (United States)

    Wang, Lei; Su, Hongyan; Han, Liya; Wang, Chuanqi; Sun, Yanlin; Liu, Fenghong

    2014-07-15

    Mitogen-activated protein kinase (MAPK) cascades are universal signal transduction modules that play essential roles in plant growth, development and stress response. MAPK kinases (MAPKKs), which link MAPKs and MAPKK kinases (MAPKKKs), are integral in mediating various stress responses in plants. However, to date few data about the roles of poplar MAPKKs in stress signal transduction are available. In this study, we performed a systemic analysis of poplar MAPKK gene family expression profiles in response to several abiotic stresses and stress-associated hormones. Furthermore, Populus trichocarpa MAPKK4 (PtMKK4) was chosen for functional characterization. Transgenic analysis showed that overexpression of the PtMKK4 gene remarkably enhanced drought stress tolerance in the transgenic poplar plants. The PtMKK4-overexpressing plants also exhibited much lower levels of H2O2 and higher antioxidant enzyme activity after exposure to drought stress compared to the wide type lines. Besides, some drought marker genes including PtP5CS, PtSUS3, PtLTP3 and PtDREB8 exhibited higher expression levels in the transgenic lines than in the wide type under drought conditions. This study provided valuable information for understanding the putative functions of poplar MAPKKs involved in important signaling pathways under different stress conditions.

  12. Alteration of PHYA expression change circadian rhythms and timing of bud set in Populus.

    Science.gov (United States)

    Kozarewa, Iwanka; Ibáñez, Cristian; Johansson, Mikael; Ogren, Erling; Mozley, David; Nylander, Eva; Chono, Makiko; Moritz, Thomas; Eriksson, Maria E

    2010-05-01

    In many temperate woody species, dormancy is induced by short photoperiods. Earlier studies have shown that the photoreceptor phytochrome A (phyA) promotes growth. Specifically, Populus plants that over-express the oat PHYA gene (oatPHYAox) show daylength-independent growth and do not become dormant. However, we show that oatPHYAox plants could be induced to set bud and become cold hardy by exposure to a shorter, non-24 h diurnal cycle that significantly alters the relative position between endogenous rhythms and perceived light/dark cycles. Furthermore, we describe studies in which the expression of endogenous Populus tremula x P. tremuloides PHYTOCHROME A (PttPHYA) was reduced in Populus trees by antisense inhibition. The antisense plants showed altered photoperiodic requirements, resulting in earlier growth cessation and bud formation in response to daylength shortening, an effect that was explained by an altered innate period that leads to phase changes of clock-associated genes such as PttCO2. Moreover, gene expression studies following far-red light pulses show a phyA-mediated repression of PttLHY1 and an induction of PttFKF1 and PttFT. We conclude that the level of PttPHYA expression strongly influences seasonally regulated growth in Populus and is central to co-ordination between internal clock-regulated rhythms and external light/dark cycles through its dual effect on the pace of clock rhythms and in light signaling.

  13. Genome resequencing in Populus: Revealing large-scale genome variation and implications on specialized-trait genomics

    Energy Technology Data Exchange (ETDEWEB)

    Muchero, Wellington [ORNL; Labbe, Jessy L [ORNL; Priya, Ranjan [University of Tennessee, Knoxville (UTK); DiFazio, Steven P [West Virginia University, Morgantown; Tuskan, Gerald A [ORNL

    2014-01-01

    To date, Populus ranks among a few plant species with a complete genome sequence and other highly developed genomic resources. With the first genome sequence among all tree species, Populus has been adopted as a suitable model organism for genomic studies in trees. However, far from being just a model species, Populus is a key renewable economic resource that plays a significant role in providing raw materials for the biofuel and pulp and paper industries. Therefore, aside from leading frontiers of basic tree molecular biology and ecological research, Populus leads frontiers in addressing global economic challenges related to fuel and fiber production. The latter fact suggests that research aimed at improving quality and quantity of Populus as a raw material will likely drive the pursuit of more targeted and deeper research in order to unlock the economic potential tied in molecular biology processes that drive this tree species. Advances in genome sequence-driven technologies, such as resequencing individual genotypes, which in turn facilitates large scale SNP discovery and identification of large scale polymorphisms are key determinants of future success in these initiatives. In this treatise we discuss implications of genome sequence-enable technologies on Populus genomic and genetic studies of complex and specialized-traits.

  14. An In vitro Study of Bio-Control and Plant Growth Promotion Potential of Salicaceae Endophytes.

    Science.gov (United States)

    Kandel, Shyam L; Firrincieli, Andrea; Joubert, Pierre M; Okubara, Patricia A; Leston, Natalie D; McGeorge, Kendra M; Mugnozza, Giuseppe S; Harfouche, Antoine; Kim, Soo-Hyung; Doty, Sharon L

    2017-01-01

    Microbial communities in the endosphere of Salicaceae plants, poplar (Populus trichocarpa) and willow (Salix sitchensis), have been demonstrated to be important for plant growth promotion, protection from biotic and abiotic stresses, and degradation of toxic compounds. Our study aimed to investigate bio-control activities of Salicaceae endophytes against various soil borne plant pathogens including Rhizoctonia solani AG-8, Fusarium culmorum, Gaeumannomyces graminis var. tritici, and Pythium ultimum. Additionally, different plant growth promoting traits such as biological nitrogen fixation (BNF), indole-3-acetic acid (IAA) biosynthesis, phosphate solubilization, and siderophore production were assessed in all bio-control positive strains. Burkholderia, Rahnella, Pseudomonas, and Curtobacterium were major endophyte genera that showed bio-control activities in the in-vitro assays. The bio-control activities of Burkholderia strains were stronger across all tested plant pathogens as compared to other stains. Genomes of sequenced Burkholderia strains WP40 and WP42 were surveyed to identify the putative genes involved in the bio-control activities. The ocf and hcnABC gene clusters responsible for biosynthesis of the anti-fungal metabolites, occidiofungin and hydrogen cyanide, are present in the genomes of WP40 and WP42. Nearly all endophyte strains showing the bio-control activities produced IAA, solubilized tricalcium phosphate, and synthesized siderophores in the culture medium. Moreover, some strains reduced acetylene into ethylene in the acetylene reduction assay, a common assay used for BNF. Salicaceae endophytes could be useful for bio-control of various plant pathogens, and plant growth promotion possibly through the mechanisms of BNF, IAA production, and nutrient acquisition.

  15. An In vitro Study of Bio-Control and Plant Growth Promotion Potential of Salicaceae Endophytes

    Science.gov (United States)

    Kandel, Shyam L.; Firrincieli, Andrea; Joubert, Pierre M.; Okubara, Patricia A.; Leston, Natalie D.; McGeorge, Kendra M.; Mugnozza, Giuseppe S.; Harfouche, Antoine; Kim, Soo-Hyung; Doty, Sharon L.

    2017-01-01

    Microbial communities in the endosphere of Salicaceae plants, poplar (Populus trichocarpa) and willow (Salix sitchensis), have been demonstrated to be important for plant growth promotion, protection from biotic and abiotic stresses, and degradation of toxic compounds. Our study aimed to investigate bio-control activities of Salicaceae endophytes against various soil borne plant pathogens including Rhizoctonia solani AG-8, Fusarium culmorum, Gaeumannomyces graminis var. tritici, and Pythium ultimum. Additionally, different plant growth promoting traits such as biological nitrogen fixation (BNF), indole-3-acetic acid (IAA) biosynthesis, phosphate solubilization, and siderophore production were assessed in all bio-control positive strains. Burkholderia, Rahnella, Pseudomonas, and Curtobacterium were major endophyte genera that showed bio-control activities in the in-vitro assays. The bio-control activities of Burkholderia strains were stronger across all tested plant pathogens as compared to other stains. Genomes of sequenced Burkholderia strains WP40 and WP42 were surveyed to identify the putative genes involved in the bio-control activities. The ocf and hcnABC gene clusters responsible for biosynthesis of the anti-fungal metabolites, occidiofungin and hydrogen cyanide, are present in the genomes of WP40 and WP42. Nearly all endophyte strains showing the bio-control activities produced IAA, solubilized tricalcium phosphate, and synthesized siderophores in the culture medium. Moreover, some strains reduced acetylene into ethylene in the acetylene reduction assay, a common assay used for BNF. Salicaceae endophytes could be useful for bio-control of various plant pathogens, and plant growth promotion possibly through the mechanisms of BNF, IAA production, and nutrient acquisition.

  16. Conservation, Divergence, and Genome-Wide Distribution of PAL and POX A Gene Families in Plants

    Directory of Open Access Journals (Sweden)

    H. C. Rawal

    2013-01-01

    Full Text Available Genome-wide identification and phylogenetic and syntenic comparison were performed for the genes responsible for phenylalanine ammonia lyase (PAL and peroxidase A (POX A enzymes in nine plant species representing very diverse groups like legumes (Glycine max and Medicago truncatula, fruits (Vitis vinifera, cereals (Sorghum bicolor, Zea mays, and Oryza sativa, trees (Populus trichocarpa, and model dicot (Arabidopsis thaliana and monocot (Brachypodium distachyon species. A total of 87 and 1045 genes in PAL and POX A gene families, respectively, have been identified in these species. The phylogenetic and syntenic comparison along with motif distributions shows a high degree of conservation of PAL genes, suggesting that these genes may predate monocot/eudicot divergence. The POX A family genes, present in clusters at the subtelomeric regions of chromosomes, might be evolving and expanding with higher rate than the PAL gene family. Our analysis showed that during the expansion of POX A gene family, many groups and subgroups have evolved, resulting in a high level of functional divergence among monocots and dicots. These results will act as a first step toward the understanding of monocot/eudicot evolution and functional characterization of these gene families in the future.

  17. Stress-responsive hydroxycinnamate glycosyltransferase modulates phenylpropanoid metabolism in Populus.

    Science.gov (United States)

    Babst, Benjamin A; Chen, Han-Yi; Wang, Hong-Qiang; Payyavula, Raja S; Thomas, Tina P; Harding, Scott A; Tsai, Chung-Jui

    2014-08-01

    The diversity of phenylpropanoids offers a rich inventory of bioactive chemicals that can be exploited for plant improvement and human health. Recent evidence suggests that glycosylation may play a role in the partitioning of phenylpropanoid precursors for a variety of downstream uses. This work reports the functional characterization of a stress-responsive glycosyltransferase, GT1-316 in Populus. GT1-316 belongs to the UGT84A subfamily of plant glycosyltransferase family 1 and is designated UGT84A17. Recombinant protein analysis showed that UGT84A17 is a hydroxycinnamate glycosyltransferase and able to accept a range of unsubstituted and substituted cinnamic and benzoic acids as substrates in vitro. Overexpression of GT1-316 in transgenic Populus led to plant-wide increases of hydroxycinnamoyl-glucose esters, which were further elevated under N-limiting conditions. Levels of the two most abundant flavonoid glycosides, rutin and kaempferol-3-O-rutinoside, decreased, while levels of other less abundant flavonoid and phenylpropanoid conjugates increased in leaves of the GT1-316-overexpressing plants. Transcript levels of representative phenylpropanoid pathway genes were unchanged in transgenic plants, supporting a glycosylation-mediated redirection of phenylpropanoid carbon flow as opposed to enhanced phenylpropanoid pathway flux. The metabolic response of N-replete transgenic plants overlapped with that of N-stressed wild types, as the majority of phenylpropanoid derivatives significantly affected by GT1-316 overexpression were also significantly changed by N stress in the wild types. These results suggest that UGT84A17 plays an important role in phenylpropanoid metabolism by modulating biosynthesis of hydroxycinnamoyl-glucose esters and their derivatives in response to developmental and environmental cues.

  18. Diversification in the genetic architecture of gene expression and transcriptional networks in organ differentiation of Populus

    OpenAIRE

    Drost, Derek R.; Benedict, Catherine I.; Berg, Arthur; Novaes, Evandro; Novaes, Carolina R. D. B.; Yu, Qibin; Dervinis, Christopher; Jessica M Maia; Yap, John; Miles, Brianna; Kirst, Matias

    2010-01-01

    A fundamental goal of systems biology is to identify genetic elements that contribute to complex phenotypes and to understand how they interact in networks predictive of system response to genetic variation. Few studies in plants have developed such networks, and none have examined their conservation among functionally specialized organs. Here we used genetical genomics in an interspecific hybrid population of the model hardwood plant Populus to uncover transcriptional networks in xylem, leav...

  19. Metabolomics study of Populus type propolis.

    Science.gov (United States)

    Anđelković, Boban; Vujisić, Ljubodrag; Vučković, Ivan; Tešević, Vele; Vajs, Vlatka; Gođevac, Dejan

    2017-02-20

    Herein, we propose rapid and simple spectroscopic methods to determine the chemical composition of propolis derived from various Populus species using a metabolomics approach. In order to correlate variability in Populus type propolis composition with the altitude of its collection, NMR, IR, and UV spectroscopy followed by OPLS was conducted. The botanical origin of propolis was established by comparing propolis spectral data to those of buds of various Populus species. An O2PLS method was utilized to integrate two blocks of data. According to OPLS and O2PLS, the major compounds in propolis samples, collected from temperate continental climate above 500m, were phenolic glycerides originating from P. tremula buds. Flavonoids were predominant in propolis samples collected below 400m, originating from P. nigra and P. x euramericana buds. Samples collected at 400-500m were of mixed origin, with variable amounts of all detected metabolites. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Tree rings, Populus nigra L., as mercury data logger in aquatic environments: case study of an historically contaminated environment.

    Science.gov (United States)

    Abreu, S N; Soares, A M V M; Nogueira, A J A; Morgado, F

    2008-03-01

    In this study, a tree (Populus nigra L.) has been presented as data logger of mercury release in aquatic environments using tree rings chemistry to provide chronological historical monitoring of mercury discharge from a chlor-alkali industrial effluent to a coastal lagoon. Tree rings (Populus nigra L.) as mercury data logger is suggested by mercury accumulation trends in the tree rings reflecting the industrial plant capacity increments in the early stages of mercury discharges and enhancing industrial plant controls to minimize mercury discharges in the last two decades after imposed global regulations on mercury emissions.

  1. Knockdown of a Laccase in Populus deltoides Confers Altered Cell Wall Chemistry and Increased Sugar Release

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, Anthony C.; Jawdy, Sara; Gunter, Lee; Gjersing, Erica; Sykes, Robert; Hinchee, Maud A. W.; Winkeler, Kimberly A.; Collins, Cassandra M.; Engle, Nancy; Tschaplinski, Timothy J.; Yang, Xiaohan; Tuskan, Gerald A.; Muchero, Wellington; Chen, Jin-Gui

    2016-10-01

    Plant laccases are thought to function in the oxidation of monolignols which leads to higher order lignin formation. Only a hand-full of laccases in plants have been functionally evaluated and as such little is known about the breadth of their impact on cell wall chemistry or structure. Here we describe a previously uncharacterized laccase from Populus, encoded by locus Potri.008G064000, whose reduced expression resulted in transgenic Populus trees with changes in syringyl/guaiacyl (S/G) ratios as well as altered sugar release phenotypes. These phenotypes are consistent with plant biomass exhibiting reduced recalcitrance. Interestingly, the transgene effect on recalcitrance is dependent on a mild pretreatment prior to chemical extraction of sugars. Metabolite profiling suggests the transgene modulates phenolics that are associated with the cell wall structure. We propose that this particular laccase has a range of functions related to oxidation of phenolics and conjugation of flavonoids that interact with lignin in the cell wall.

  2. Knockdown of a laccase in Populus deltoides confers altered cell wall chemistry and increased sugar release.

    Science.gov (United States)

    Bryan, Anthony C; Jawdy, Sara; Gunter, Lee; Gjersing, Erica; Sykes, Robert; Hinchee, Maud A W; Winkeler, Kimberly A; Collins, Cassandra M; Engle, Nancy; Tschaplinski, Timothy J; Yang, Xiaohan; Tuskan, Gerald A; Muchero, Wellington; Chen, Jin-Gui

    2016-10-01

    Plant laccases are thought to function in the oxidation of monolignols which leads to higher order lignin formation. Only a hand-full of laccases in plants have been functionally evaluated, and as such little is known about the breadth of their impact on cell wall chemistry or structure. Here, we describe a previously uncharacterized laccase from Populus, encoded by locus Potri.008G064000, whose reduced expression resulted in transgenic Populus trees with changes in syringyl/guaiacyl ratios as well as altered sugar release phenotypes. These phenotypes are consistent with plant biomass exhibiting reduced recalcitrance. Interestingly, the transgene effect on recalcitrance is dependent on a mild pretreatment prior to chemical extraction of sugars. Metabolite profiling suggests the transgene modulates phenolics that are associated with the cell wall structure. We propose that this particular laccase has a range of functions related to oxidation of phenolics and conjugation of flavonoids that interact with lignin in the cell wall.

  3. Cloning and Expression Patterns of PtSUS1 in Populus tomentosa%毛白杨蔗糖合酶基因PtSUS1的克隆及其表达模式分析

    Institute of Scientific and Technical Information of China (English)

    李英; 陈仲; 李昊; 郭斌; 王佳; 安新民

    2012-01-01

    蔗糖合酶(sucrose synthase)与植物库强调节、次生壁的形成和纤维素合成等有着密切的联系,其中在纤维素合成过程中的作用尤为显著.本研究根据我们已获得的毛白杨PtSUS1基因片段设计引物,采用RACE技术,获得了毛白杨PtSUS1的基因序列,测序结果显示该基因序列全长为2 669 bp,包括一个完整的阅读框,编码805个氨基酸.通过Blast检索分析表明,PtSUS1与拟南芥、巨桉、陆地棉、温州蜜柑、毛果杨SUS1的核酸和氨基酸序列的同源性分别达到76%~97%和82%~97%.运用生物信息软件对PtSUS1编码的蛋白进行了二级结构预测和功能位点分析,结果显示该蛋白氨基酸序列包括两个功能域,存在可能的磷酸化位点38个,无跨膜结构域存在.系统进化分析表明PtSUS1与PtSUS2关系最为接近.RT-PCR分析结果显示,PtSUS1在被检测的毛白杨根、茎、叶及雌雄花芽组织和器官中均有表达,呈现组成型表达模式.该研究为进一步深入探索毛白杨蔗糖合酶基因PtSUS1的功能奠定了基础.%Sucrose synthase (SUS) was closely associated with sink strength, secondary wall formationand cellulose synthesis in plant. Among these items, cellulose synthesis is considered to be the most important. According to the known gene fragment of PtSUSl and the principle of RACE amplification, we got the gene sequence of PtSUSl from Populous tomentosa. The full sequence of PtSUSl which contains an open reading frame (ORF) is 2 669 bp encoding a deduced amino acid sequence of 805 residues. Blast analysis results indicated that the homology was as high as 76% to 97% and 81% to 97%, respectively, when compared PtSUSl sequence of amino acid and nucle-otide with the ones of Arabidopsis thaliana, Eucalyptus grandis, Gossypium hirsutum, Citrus unshiu, and Populus trichocarpa. Furthermore, secondary structure and functional sites in amino acid sequences have been predicted by the bioinformatics

  4. Research on Species Diversity Characteristics of Chinese Endemic Plant Populus shanxiensis%中国特有植物青毛杨群落物种多样性特征研究

    Institute of Scientific and Technical Information of China (English)

    孙东辉; 郭东罡; 上官铁梁; 王振军

    2011-01-01

    [目的]研究山西黑茶山青毛杨群落物种多样性。[方法]采用样方法进行样地调查,依据重要值指标,应用丰富度指数(N0)、Simpson指数(λ)、Shannon-Weiner指数(H')和均匀度指数(E1和E5)进行分析研究。[结果]青毛杨群落物种多样性指数不仅取决于群落的种类组成,而且与种间的重要值配置有密切关系。青毛杨群落内各层物种丰富度指数和多样性指数的大小为草本层〉灌木层〉乔木层;丰富度指数与多样性指数呈正相关关系,而群落均匀度指数的变化与丰富度指数和多样性指数的变化趋势有所不同,且均匀度与优势度呈负相关关系。[结论]进一步了解和认识了青毛杨的生长现状及生长环境,从而为保护这一濒危物种奠定一定的理论基础,同时也为今后濒危物种及相关学科的研究提供基础资料。%[Objective] This study aimed at researching the species diversity of Populus shanxiensis community in Heichashan Mountain. [Method] Based on sampling methods, investigation in sampling spots was carried out according to the important indicator, the abundance index (N0), Simpson index (λ), Shannon-Weiner index (H') and homogeneity index (E1 and E5) were used for analysis. [Results] Species diversity index of Populus shanxiensis community was not only depended on the species compositions of communities, but also closely related to the important value of species. The order of abundance index and diversity index in each layer of Populus shanxiensis community was herb layershrub layertree layer, and the abundance index was positively related to the diversity index; while the variation trend of community homogeneity index was different from that of abundance index and diversity index, and the homogeneity had shown negative correlation with the dominance. [Conclusion] In this study, the growth status and conditions of Populus shanxiensis were further

  5. POGs2: a web portal to facilitate cross-species inferences about protein architecture and function in plants.

    Directory of Open Access Journals (Sweden)

    Michael Tomcal

    Full Text Available The Putative orthologous Groups 2 Database (POGs2 (http://pogs.uoregon.edu/ integrates information about the inferred proteomes of four plant species (Arabidopsis thaliana, Zea mays, Orza sativa, and Populus trichocarpa in a display that facilitates comparisons among orthologs and extrapolation of annotations among species. A single-page view collates key functional data for members of each Putative Orthologous Group (POG: graphical representations of InterPro domains, predicted and established intracellular locations, and imported gene descriptions. The display incorporates POGs predicted by two different algorithms as well as gene trees, allowing users to evaluate the validity of POG memberships. The web interface provides ready access to sequences and alignments of POG members, as well as sequences, alignments, and domain architectures of closely-related paralogs. A simple and flexible search interface permits queries by BLAST and by any combination of gene identifier, keywords, domain names, InterPro identifiers, and intracellular location. The concurrent display of domain architectures for orthologous proteins highlights errors in gene models and false-negatives in domain predictions. The POGs2 layout is also useful for exploring candidate genes identified by transposon tagging, QTL mapping, map-based cloning, and proteomics, and for navigating between orthologous groups that belong to the same gene family.

  6. Evolution of plant defense mechanisms. Relationships of phenylcoumaran benzylic ether reductases to pinoresinol-lariciresinol and isoflavone reductases.

    Science.gov (United States)

    Gang, D R; Kasahara, H; Xia, Z Q; Vander Mijnsbrugge, K; Bauw, G; Boerjan, W; Van Montagu, M; Davin, L B; Lewis, N G

    1999-03-12

    Pinoresinol-lariciresinol and isoflavone reductase classes are phylogenetically related, as is a third, the so-called "isoflavone reductase homologs." This study establishes the first known catalytic function for the latter, as being able to engender the NADPH-dependent reduction of phenylcoumaran benzylic ethers. Accordingly, all three reductase classes are involved in the biosynthesis of important and related phenylpropanoid-derived plant defense compounds. In this investigation, the phenylcoumaran benzylic ether reductase from the gymnosperm, Pinus taeda, was cloned, with the recombinant protein heterologously expressed in Escherichia coli. The purified enzyme reduces the benzylic ether functionalities of both dehydrodiconiferyl alcohol and dihydrodehydrodiconiferyl alcohol, with a higher affinity for the former, as measured by apparent Km and Vmax values and observed kinetic 3H-isotope effects. It abstracts the 4R-hydride of the required NADPH cofactor in a manner analogous to that of the pinoresinol-lariciresinol reductases and isoflavone reductases. A similar catalytic function was observed for the corresponding recombinant reductase whose gene was cloned from the angiosperm, Populus trichocarpa. Interestingly, both pinoresinol-lariciresinol reductases and isoflavone reductases catalyze enantiospecific conversions, whereas the phenylcoumaran benzylic ether reductase only shows regiospecific discrimination. A possible evolutionary relationship among the three reductase classes is proposed, based on the supposition that phenylcoumaran benzylic ether reductases represent the progenitors of pinoresinol-lariciresinol and isoflavone reductases.

  7. Terra Populus and DataNet Collaboration

    Science.gov (United States)

    Kugler, T.; Ruggles, S.; Fitch, C. A.; Clark, P. D.; Sobek, M.; Van Riper, D.

    2012-12-01

    Terra Populus, part of NSF's new DataNet initiative, is developing organizational and technical infrastructure to integrate, preserve, and disseminate data describing changes in the human population and environment over time. Terra Populus will incorporate large microdata and aggregate census datasets from the United States and around the world, as well as land use, land cover, climate and other environmental datasets. These data are widely dispersed, exist in a variety of data structures, have incompatible or inadequate metadata, and have incompatible geographic identifiers. Terra Populus is developing methods of integrating data from different domains and translating across data structures based on spatio-temporal linkages among data contents. The new infrastructure will enable researchers to identify and merge data from heterogeneous sources to study the relationships between human behavior and the natural world. Terra Populus will partner with data archives, data producers, and data users to create a sustainable international organization that will guarantee preservation and access over multiple decades. Terra Populus is also collaborating with the other projects in the DataNet initiative - DataONE, the DataNet Federation Consortium (DFC) and Sustainable Environment-Actionable Data (SEAD). Taken together, the four projects address aspects of the entire data lifecycle, including planning, collection, documentation, discovery, integration, curation, preservation, and collaboration; and encompass a wide range of disciplines including earth sciences, ecology, social sciences, hydrology, oceanography, and engineering. The four projects are pursuing activities to share data, tools, and expertise between pairs of projects as well as collaborating across the DataNet program on issues of cyberinfrastructure and community engagement. Topics to be addressed through program-wide collaboration include technical, organizational, and financial sustainability; semantic

  8. Genotyping-by-sequencing for Populus population genomics: an assessment of genome sampling patterns and filtering approaches.

    Directory of Open Access Journals (Sweden)

    Martin P Schilling

    Full Text Available Continuing advances in nucleotide sequencing technology are inspiring a suite of genomic approaches in studies of natural populations. Researchers are faced with data management and analytical scales that are increasing by orders of magnitude. With such dramatic advances comes a need to understand biases and error rates, which can be propagated and magnified in large-scale data acquisition and processing. Here we assess genomic sampling biases and the effects of various population-level data filtering strategies in a genotyping-by-sequencing (GBS protocol. We focus on data from two species of Populus, because this genus has a relatively small genome and is emerging as a target for population genomic studies. We estimate the proportions and patterns of genomic sampling by examining the Populus trichocarpa genome (Nisqually-1, and demonstrate a pronounced bias towards coding regions when using the methylation-sensitive ApeKI restriction enzyme in this species. Using population-level data from a closely related species (P. tremuloides, we also investigate various approaches for filtering GBS data to retain high-depth, informative SNPs that can be used for population genetic analyses. We find a data filter that includes the designation of ambiguous alleles resulted in metrics of population structure and Hardy-Weinberg equilibrium that were most consistent with previous studies of the same populations based on other genetic markers. Analyses of the filtered data (27,910 SNPs also resulted in patterns of heterozygosity and population structure similar to a previous study using microsatellites. Our application demonstrates that technically and analytically simple approaches can readily be developed for population genomics of natural populations.

  9. Biochemical basis of drought tolerance in hybrid Populus grown under field production conditions. CRADA final report

    Energy Technology Data Exchange (ETDEWEB)

    Tschaplinski, T.J.; Tuskan, G.A. [Oak Ridge National Lab., TN (United States); Wierman, C. [Boise Cascade Corp., Wallula, WA (United States)

    1997-04-01

    The purpose of this cooperative effort was to assess the use of osmotically active compounds as molecular selection criteria for drought tolerance in Populus in a large-scale field trial. It is known that some plant species, and individuals within a plant species, can tolerate increasing stress associated with reduced moisture availability by accumulating solutes. The biochemical matrix of such metabolites varies among species and among individuals. The ability of Populus clones to tolerate drought has equal value to other fiber producers, i.e., the wood products industry, where irrigation is used in combination with other cultural treatments to obtain high dry weight yields. The research initially involved an assessment of drought stress under field conditions and characterization of changes in osmotic constitution among the seven clones across the six moisture levels. The near-term goal was to provide a mechanistic basis for clonal differences in productivity under various irrigation treatments over time.

  10. Populus euphratica, a Tolerant Model but Endangered Arborescent Species

    Institute of Scientific and Technical Information of China (English)

    Gu Ruisheng; Pei Dong

    2005-01-01

    @@ Populus euphratica is a most tolerant arborescent species to abiotic stress. It can adapt to extreme conditions, ranging from flood to atmosphere extremely dry, hot from + 54 ℃ to - 45 ℃, and from normal soil to the soil with very high salt concentration ( to 2 ~5%) although being a non-halophyte. However, the natural stands of P. euphratica have been shrinking tremendously for the past decades and some populations are facing the fate of extinction. The preservation of existing resources should be carried out as a burning issue. In parallel, P. euphratica could be taken as a model plant to explore the molecular mechanism of abiotic-stress tolerance and to exploit its tolerant genes due to its smaller genome and easy molecular manipulation. The measures for preservation, germ-plasma exploitation, tolerance mechanism exploration and resource utilization were also discussed in this paper.

  11. Establishment of cell suspension line of Populus tomentosa Carr

    Institute of Scientific and Technical Information of China (English)

    YAO Na; ZHANG Zhi-yi; AN Xin-min; YANG Kai

    2008-01-01

    Leaves of fine Populus tomentosa genotype TC152 were used as explants to establish cell suspension lines. The effects of plant growth regulators on callus induction and establishment of cell suspension lines were studied. The callus induction rate was the highest on a MS solid medium supplemented with 1.0 mg·L-1 2,4-D. A cell suspension line could be obtained by inoculating calli which were not subeultured into a MS liquid medium supplemented with 1.5 mg·L-1 2,4-D. The best subculture medium was MS+ 0.8 mg·L-1 2,4-D + 30 g·L-1 sucrose with a subculture cycle of seven days.

  12. Cross Breeding of Populus and Its Hybrids for Cold Resistance

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Populus tomentosa was crossed with P. tremuloidis, P. grandidentata, P. alba × P. grandidentata and P. alba × Ulmus pumila in order to maintain its rapid growth and high wood quality and improve its resistance to cold. Two methods were used to increase the germination rate from 1.5% to 41.1% and the remaining rate from 1.7% to 44.2%. Forty crossing combinations were conducted and 2 744 hybrid seedlings were obtained. MX4 × P. grandidentata (G-1-58), MX3 × P. tremuloidis (T-44-60), MX2 × P. tremuloidis (l-13-87-37) and MX2 × (P. alba × P. grandidentata) were regarded as superior combinations after analysis and selection. Thirty seedlings of these combinations and 11 triploid seedlings identified by counting their chromosomes were selected as super plants.

  13. Response of the accumulation of proline in the bodies of Populus euphratica to the change of groundwater level at the lower reaches of Tarim River

    Institute of Scientific and Technical Information of China (English)

    CHEN Yaning; CHEN Yapeng; LI Weihong; ZHANG Hongfeng

    2003-01-01

    The content of proline in the plant bodies is closely related to the converse-succession-resistant capability of the plants. In this paper, the relationship between the proline accumulation in the bodies of Populus euphratica and the change of groundwater level is analyzed by taking Populus euphratica, the main community-building species of the desert riparian forests along the Tarim River, as the research object. The research results show that the accumulation of proline in the bodies of Populus euphratica is closely related to the change of groundwater level gradient under drought stress, it increases with the drawdown of groundwater level and the increase of moisture stress degree; the accumulation of proline in the bodies of Populus euphratica has two extremely high points at the groundwater depth ranges of 3.64-5.14 m and 9.46-10.16 m. Combining the field investigation and the analysis of the plots, it is considered that the groundwater level of 3.5-4.5 m is rational for the growth of Populus euphratica. The stress groundwater depth for the normal growth and the critical one for the survival of Populus euphratica are below 4.5 m and 9-10 m respectively at the lower reaches of the Tarim River.

  14. Sapflow of hybrid poplar (Populus nigra L. x P. maximowiczii A. Henry 'NM6') during phytoremediation of landfill leachate

    Science.gov (United States)

    Ronald S., Jr. Zalesny; Adam H. Wiese; Edmund O. Bauer; Don E. Riemenschneider

    2006-01-01

    Poplars are ideal for phytoremediation because of their high water usage, fast growth, and deep root systems. We measured in 2002 and 2003 the sapflow of hybrid poplars (Populus nigra L. x P. maximowiczii A. Henry 'NM6') planted in 1999 for phytoremediation of a landfill in Rhinelander, WI, USA (45.6?N, 89.4?W).

  15. High-density linkage mapping and evolution of paralogs and orthologs in Salix and Populus

    Directory of Open Access Journals (Sweden)

    Öst Torbjörn

    2010-02-01

    Full Text Available Abstract Background Salix (willow and Populus (poplar are members of the Salicaceae family and they share many ecological as well as genetic and genomic characteristics. The interest of using willow for biomass production is growing, which has resulted in increased pressure on breeding of high yielding and resistant clones adapted to different environments. The main purpose of this work was to develop dense genetic linkage maps for mapping of traits related to yield and resistance in willow. We used the Populus trichocarpa genome to extract evenly spaced markers and mapped the orthologous loci in the willow genome. The marker positions in the two genomes were used to study genome evolution since the divergence of the two lineages some 45 mya. Results We constructed two linkage maps covering the 19 linkage groups in willow. The most detailed consensus map, S1, contains 495 markers with a total genetic distance of 2477 cM and an average distance of 5.0 cM between the markers. The S3 consensus map contains 221 markers and has a total genetic distance of 1793 cM and an average distance of 8.1 cM between the markers. We found high degree of synteny and gene order conservation between willow and poplar. There is however evidence for two major interchromosomal rearrangements involving poplar LG I and XVI and willow LG Ib, suggesting a fission or a fusion in one of the lineages, as well as five intrachromosomal inversions. The number of silent substitutions were three times lower (median: 0.12 between orthologs than between paralogs (median: 0.37 - 0.41. Conclusions The relatively slow rates of genomic change between willow and poplar mean that the genomic resources in poplar will be most useful in genomic research in willow, such as identifying genes underlying QTLs of important traits. Our data suggest that the whole-genome duplication occurred long before the divergence of the two genera, events which have until now been regarded as contemporary

  16. Newly identified helper bacteria stimulate ectomycorrhizal formation in Populus

    OpenAIRE

    Labbé, Jessy L.; Weston, David J; Nora eDunkirk; Pelletier, Dale A.; Tuskan, Gerald A.

    2014-01-01

    Mycorrhiza helper bacteria (MHB) are known to increase host root colonization by mycorrhizal fungi but the molecular mechanisms and potential tripartite interactions are poorly understood. Through an effort to study Populus microbiome, we isolated 21 Pseudomonas strains from native Populus deltoides roots. These bacterial isolates were characterized and screened for MHB effectiveness on the Populus-Laccaria system. Two additional Pseudomonas strains (i.e., Pf-5 and BBc6R8) from existing colle...

  17. Diversification and expression of the PIN, AUX/LAX and ABCB families of putative auxin transporters in Populus

    Directory of Open Access Journals (Sweden)

    Nicola eCarraro

    2012-02-01

    Full Text Available Intercellular transport of the plant hormone auxin is mediated by three families of membrane-bound protein carriers, with the PIN and ABCB families coding primarily for efflux proteins and the AUX/LAX family coding for influx proteins. In the last decade our understanding of gene and protein function for these transporters in Arabidopsis has expanded rapidly but very little is known about their role in woody plant development. Here we present a comprehensive account of all three families in the model woody species Populus, including chromosome distribution, protein structure, quantitative gene expression, and evolutionary relationships. The PIN and AUX/LAX gene families in Populus comprise 16 and 8 members respectively, and show evidence for the retention of paralogs following a relatively recent whole genome duplication. There is also evidence for differential expression across tissues within many gene pairs. The ABCB family is previously undescribed in Populus and includes 20 members, showing a much deeper evolutionary history including both tandem and whole genome duplication as well as probable loss. A striking number of these transporters are expressed in developing Populus stems and we suggest that evolutionary and structural relationships with known auxin transporters in Arabidopsis can point toward candidate genes for further study in Populus. This is especially important for the ABCBs, which is a large family and includes members in Arabidopsis that are able to transport other substrates in addition to auxin. Protein modeling, sequence alignment and expression data all point to ABCB1.1 as a likely auxin transport protein in Populus. Given that basipetal auxin flow through the cambial zone shapes the development of woody stems, it is important that we identify the full complement of proteins involved in this process. This work should lay the foundation for studies targeting specific proteins for functional characterization and in situ

  18. Stress Responsive Zinc-finger Protein Gene of Populus euphratica in Tobacco Enhances Salt Tolerance

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The Populus euphratica stress responsive zinc-finger protein gene PSTZ, which encodes a protein including typical Cys2/His2 zinc finger structure, was isolated by reverse transcription-polymerase chain reaction from P. euphratica.Northern hybridization revealed that its expression was induced under drought and salt stress conditions. To examine its function, cDNA of the PSTZ gene, driven by the cauliflower mosaic virus 35S promoter, was cloned into a plant expression vector pBin438 and introduced into tobacco plants. Transgenic tobacco showed an enhanced salt tolerance, suggesting that PSTZ may play a role in plant responsiveness to salt stress.

  19. Deciphering evolutionary strata on plant sex chromosomes and fungal mating-type chromosomes through compositional segmentation.

    Science.gov (United States)

    Pandey, Ravi S; Azad, Rajeev K

    2016-03-01

    Sex chromosomes have evolved from a pair of homologous autosomes which differentiated into sex determination systems, such as XY or ZW system, as a consequence of successive recombination suppression between the gametologous chromosomes. Identifying the regions of recombination suppression, namely, the "evolutionary strata", is central to understanding the history and dynamics of sex chromosome evolution. Evolution of sex chromosomes as a consequence of serial recombination suppressions is well-studied for mammals and birds, but not for plants, although 48 dioecious plants have already been reported. Only two plants Silene latifolia and papaya have been studied until now for the presence of evolutionary strata on their X chromosomes, made possible by the sequencing of sex-linked genes on both the X and Y chromosomes, which is a requirement of all current methods that determine stratum structure based on the comparison of gametologous sex chromosomes. To circumvent this limitation and detect strata even if only the sequence of sex chromosome in the homogametic sex (i.e. X or Z chromosome) is available, we have developed an integrated segmentation and clustering method. In application to gene sequences on the papaya X chromosome and protein-coding sequences on the S. latifolia X chromosome, our method could decipher all known evolutionary strata, as reported by previous studies. Our method, after validating on known strata on the papaya and S. latifolia X chromosome, was applied to the chromosome 19 of Populus trichocarpa, an incipient sex chromosome, deciphering two, yet unknown, evolutionary strata. In addition, we applied this approach to the recently sequenced sex chromosome V of the brown alga Ectocarpus sp. that has a haploid sex determination system (UV system) recovering the sex determining and pseudoautosomal regions, and then to the mating-type chromosomes of an anther-smut fungus Microbotryum lychnidis-dioicae predicting five strata in the non

  20. Establishment of in vitro culture of Populus euphratica Olivier

    Institute of Scientific and Technical Information of China (English)

    Zhao Peng; Dong Zhan-yuan; Sun Hong-bin; Zhao Ju-ying; Wang Hua-fang

    2006-01-01

    The purpose of our study was to establish a regeneration system for micropropagation of Populus euphratica Olivier. On the basis of an analysis of plant leaf mineral nutrients, a special medium was proposed, called MP2. In optimizing media for in vitro plant cultures including MS, B5 and MP2 media we employed hormones, auxin IAA, cytokine benzyladenine (BAP) and gibberellic acid (GA) in our factorial experiments on media. Adventitious shoots were derived from cuttings of adult plants taken from Xingjiang, west China, on selected media with MP2 + 0.5 mg.L-1 BA + 0.1 mg·L-1 NAA. The shoots were elongated on a medium with 0.25mg.L-1 BAP, 0.1 mg.L-1NAA and 2 mg·L-1 GA and were then rooted on a medium with 0.2-0.5 mg·L-1 IBA. All the media were incorporated with 30 g·L-1 sucrose and an adjusted pH at 6.3.

  1. Differential phylogenetic expansions in BAHD acyltransferases across five angiosperm taxa and evidence of divergent expression among Populus paralogues

    Directory of Open Access Journals (Sweden)

    Johnson Virgil E

    2011-05-01

    Full Text Available Abstract Background BAHD acyltransferases are involved in the synthesis and elaboration of a wide variety of secondary metabolites. Previous research has shown that characterized proteins from this family fall broadly into five major clades and contain two conserved protein motifs. Here, we aimed to expand the understanding of BAHD acyltransferase diversity in plants through genome-wide analysis across five angiosperm taxa. We focus particularly on Populus, a woody perennial known to produce an abundance of secondary metabolites. Results Phylogenetic analysis of putative BAHD acyltransferase sequences from Arabidopsis, Medicago, Oryza, Populus, and Vitis, along with previously characterized proteins, supported a refined grouping of eight major clades for this family. Taxon-specific clustering of many BAHD family members appears pervasive in angiosperms. We identified two new multi-clade motifs and numerous clade-specific motifs, several of which have been implicated in BAHD function by previous structural and mutagenesis research. Gene duplication and expression data for Populus-dominated subclades revealed that several paralogous BAHD members in this genus might have already undergone functional divergence. Conclusions Differential, taxon-specific BAHD family expansion via gene duplication could be an evolutionary process contributing to metabolic diversity across plant taxa. Gene expression divergence among some Populus paralogues highlights possible distinctions between their biochemical and physiological functions. The newly discovered motifs, especially the clade-specific motifs, should facilitate future functional study of substrate and donor specificity among BAHD enzymes.

  2. Growth Characteristics of Four Clone of Populus alba × Populus bolleana%4个银×新杨无性系生长特性

    Institute of Scientific and Technical Information of China (English)

    王宝庆; 李丕军; 李宏; 李素琼; 雷双喜

    2011-01-01

    Growth characteristics of Populus alba X Populus bolleana plantaion in Plain Forestry Farm of Hi Area had been studied. The results showed than tree height growth of four clone of Populus alba X Populus bolleana was earlier than the breast diameter growth. There were significant differences among single plants in the middle and later periods of plant growth. The maximum of current annual increment and average annual increment of tree height appeared nearly synchronously,so did the breast diameter. The current annual increment of the tree height and the average annual increment intersected with each other nearly in 4th-6th year. The current annual increment of breast diameter and the average annual increment intersected about in 6th-7th year. But the maximum of current annual increment of timber volume appeared much more earlier than the maximum of mean annual increment;From the view of growth process of four clone of Populus alba Xpopulus bolleana produced 18 years ago,the growth can be divided into three periods;0 - 6 years were the young treelet period,during which the tree height and breast diameter grew faster;7 - 14 years were the high-growing period, during which the tree height and breast diameter grew at high speed. 15 - 18 years were the near mature period. The average current increment of Populus alba X Populus bolleana and current annual increment intersected with each other about in 16 years with quantitative mature, in this moment,the rotation of humbering can be operated.%对伊犁地区筛选的4个银×新杨无性系生长特性进行研究.结果表明,银×新杨4个无性系的高生长要早于胸径生长,生长中后期单株之间差异明显;树高连年生长量最大值与平均生长量最大值几乎同步出现,胸径亦如此,树高连年生长量在第4~6年时与平均生长量相交,胸径连年生长量和平均生长量在第6~7年时相交.从18a生的4个无性系生长过程来看,生长可分为3个时期:第0~6

  3. Genome-wide computational prediction and analysis of core promoter elements across plant monocots and dicots.

    Directory of Open Access Journals (Sweden)

    Sunita Kumari

    Full Text Available Transcription initiation, essential to gene expression regulation, involves recruitment of basal transcription factors to the core promoter elements (CPEs. The distribution of currently known CPEs across plant genomes is largely unknown. This is the first large scale genome-wide report on the computational prediction of CPEs across eight plant genomes to help better understand the transcription initiation complex assembly. The distribution of thirteen known CPEs across four monocots (Brachypodium distachyon, Oryza sativa ssp. japonica, Sorghum bicolor, Zea mays and four dicots (Arabidopsis thaliana, Populus trichocarpa, Vitis vinifera, Glycine max reveals the structural organization of the core promoter in relation to the TATA-box as well as with respect to other CPEs. The distribution of known CPE motifs with respect to transcription start site (TSS exhibited positional conservation within monocots and dicots with slight differences across all eight genomes. Further, a more refined subset of annotated genes based on orthologs of the model monocot (O. sativa ssp. japonica and dicot (A. thaliana genomes supported the positional distribution of these thirteen known CPEs. DNA free energy profiles provided evidence that the structural properties of promoter regions are distinctly different from that of the non-regulatory genome sequence. It also showed that monocot core promoters have lower DNA free energy than dicot core promoters. The comparison of monocot and dicot promoter sequences highlights both the similarities and differences in the core promoter architecture irrespective of the species-specific nucleotide bias. This study will be useful for future work related to genome annotation projects and can inspire research efforts aimed to better understand regulatory mechanisms of transcription.

  4. Prevalent role of gene features in determining evolutionary fates of whole-genome duplication duplicated genes in flowering plants.

    Science.gov (United States)

    Jiang, Wen-kai; Liu, Yun-long; Xia, En-hua; Gao, Li-zhi

    2013-04-01

    The evolution of genes and genomes after polyploidization has been the subject of extensive studies in evolutionary biology and plant sciences. While a significant number of duplicated genes are rapidly removed during a process called fractionation, which operates after the whole-genome duplication (WGD), another considerable number of genes are retained preferentially, leading to the phenomenon of biased gene retention. However, the evolutionary mechanisms underlying gene retention after WGD remain largely unknown. Through genome-wide analyses of sequence and functional data, we comprehensively investigated the relationships between gene features and the retention probability of duplicated genes after WGDs in six plant genomes, Arabidopsis (Arabidopsis thaliana), poplar (Populus trichocarpa), soybean (Glycine max), rice (Oryza sativa), sorghum (Sorghum bicolor), and maize (Zea mays). The results showed that multiple gene features were correlated with the probability of gene retention. Using a logistic regression model based on principal component analysis, we resolved evolutionary rate, structural complexity, and GC3 content as the three major contributors to gene retention. Cluster analysis of these features further classified retained genes into three distinct groups in terms of gene features and evolutionary behaviors. Type I genes are more prone to be selected by dosage balance; type II genes are possibly subject to subfunctionalization; and type III genes may serve as potential targets for neofunctionalization. This study highlights that gene features are able to act jointly as primary forces when determining the retention and evolution of WGD-derived duplicated genes in flowering plants. These findings thus may help to provide a resolution to the debate on different evolutionary models of gene fates after WGDs.

  5. Palaeogene fossil Populus leaves from Lanzhou Basin and their palaeoclimatic significance

    Institute of Scientific and Technical Information of China (English)

    SUN Bainian; YAN Defei; XIE Sanping; CONG Peiyun; XIN Cunlin; YUN Fei

    2004-01-01

    An angiosperm compression flora is found in Palaeogene from Lanzhou Basin and the cuticular analysis of Populus davidiana Dode in the flora is carefully made. Furthermore, the fossil cuticles are compared with the epidermal structures of extant Populus leaves growing in different environments, I.e. Moist, semimoist, and semiarid to arid climatic regions. The present experiments indicate that mature leaves of P. Davidiana show leaf size from big to small, leaf cuticles from thick to thin and anticlinal walls of epidermal cells from faintness to clarity along with the increase of latitudes of the plant distributions, the climatic variation from moist to arid, the annual precipitation from more to less and the annual mean temperature from high to low. The fossil P.davidiana differs from the specimens collected from Shandan in semiarid to arid climatic regions but closely resembles the Wushan leaves in a semi-moist climatic area in a lot of features. In a word, the new research may reflect that the flora lives in a semi-moist climatic environment. The present discovery of compression of Paleogene Populus davidiana is of great significance to studying vegetation types, climatic and environmental changes during the primal uplifting of the Qinghai-Tibet Plateau.

  6. Expression analysis of genes encoding mitogen-activated protein kinases in maize provides a key link between abiotic stress signaling and plant reproduction.

    Science.gov (United States)

    Sun, Wei; Chen, Hao; Wang, Juan; Sun, Hong Wei; Yang, Shu Ke; Sang, Ya Lin; Lu, Xing Bo; Xu, Xiao Hui

    2015-01-01

    Mitogen-activated protein kinases (MAPKs) play important roles in stress responses and development in plants. Maize (Zea mays), an important cereal crop, is a model plant species for molecular studies. In the last decade, several MAPKs have been identified in maize; however, their functions have not been studied extensively. Genome-wide identification and expression analysis of maize MAPK genes could provide valuable information for understanding their functions. In this study, 20 non-redundant maize MAPK genes (ZmMPKs) were identified via a genome-wide survey. Phylogenetic analysis of MAPKs from maize, rice (Oryza sativa), Arabidopsis (Arabidopsis thaliana), poplar (Populus trichocarpa), and tomato (Solanum lycopersicum) classified them into four major classes. ZmMPKs in the same class had similar domains, motifs, and genomic structures. Gene duplication investigations suggested that segmental duplications made a large contribution to the expansion of ZmMPKs. A number of cis-acting elements related to plant development and response to stress and hormones were identified in the promoter regions of ZmMPKs. Furthermore, transcript profile analysis in eight tissues and organs at various developmental stages demonstrated that most ZmMPKs were preferentially expressed in reproductive tissues and organs. The transcript abundance of most ZmMPKs changed significantly under salt, drought, cold, or abscisic acid (ABA) treatments, implying that they might participate in abiotic stress and ABA signaling. These expression analyses indicated that ZmMPKs might serve as linkers between abiotic stress signaling and plant reproduction. Our data will deepen our understanding of the complexity of the maize MAPK gene family and provide new clues to investigate their functions.

  7. Study on the Species Diversity of an Endemic Plant Populus shanxiensis C.Wang et Tung in China%中国特有植物青毛杨群落物种多样性特征研究

    Institute of Scientific and Technical Information of China (English)

    孙东辉; 郭东罡; 上官铁梁; 王振军

    2011-01-01

    [Objective]The aim was to study the species diversity of Populus shanxiensis C. Wang et Tung community in Heicha Mountain of Shanxi Province. [ Method] Through plot investigation by using quadrat method, the characteristics of species diversity of P. Shanxiensis was studied based on richness index (N0), Simpson' s index (λ), Shannon- Weiner' s index (H1) and evenness indices (E1, E5). [ Result] The species diversity index of P. Shanxiensis not only depended on the species composition of communities,but also was closely related to the important values of species. The order of species richness index and diversity index at different layers of P. Shanxiensis community was herb layer > shrub layer > tree layer;there was positive correlation between richness index and diversity index,but the change trend of evenness index was different from that of richness index and diversity index,and negative correlation between evenness index and dominance. [Conclusion]The current growth and growth environment of P. Shanxiensis were studied in the paper,so as to lay theoretical foundation for the protection of this endangered species and provide references for the research on endangered species in the future.%[目的]研究山西黑茶山青毛杨群落物种多样性.[方法]采用样方法进行样地调查,依据重要值指标,应用丰富度指数(N0)、Simpson指数(λ)、Shannon-Weiner指数(H′)和均匀度指数(E1和E5)进行分析研究.[结果]青毛杨群落物种多样性指数不仅取决于群落的种类组成,而且与种间的重要值配置有密切关系.青毛杨群落内各层物种丰富度指数和多样性指数的大小为草本层>灌木层>乔木层;丰富度指数与多样性指数呈正相关关系,而群落均匀度指数的变化与丰富度指数和多样性指数的变化趋势有所不同,且均匀度与优势度呈负相关关系.[结论]进一步了解和认识了青毛杨的生长现状及生长环境,从而为保护这一濒危物种

  8. A simple and efficient transient transformation for hybrid aspen (Populus tremula × P. tremuloides

    Directory of Open Access Journals (Sweden)

    Takata Naoki

    2012-08-01

    Full Text Available Abstract Background The genus Populus is accepted as a model system for molecular tree biology. To investigate gene functions in Populus spp. trees, generating stable transgenic lines is the common technique for functional genetic studies. However, a limited number of genes have been targeted due to the lengthy transgenic process. Transient transformation assays complementing stable transformation have significant advantages for rapid in vivo assessment of gene function. The aim of this study is to develop a simple and efficient transient transformation for hybrid aspen and to provide its potential applications for functional genomic approaches. Results We developed an in planta transient transformation assay for young hybrid aspen cuttings using Agrobacterium-mediated vacuum infiltration. The transformation conditions such as the infiltration medium, the presence of a surfactant, the phase of bacterial growth and bacterial density were optimized to achieve a higher transformation efficiency in young aspen leaves. The Agrobacterium infiltration assay successfully transformed various cell types in leaf tissues. Intracellular localization of four aspen genes was confirmed in homologous Populus spp. using fusion constructs with the green fluorescent protein. Protein-protein interaction was detected in transiently co-transformed cells with bimolecular fluorescence complementation technique. In vivo promoter activity was monitored over a few days in aspen cuttings that were transformed with luciferase reporter gene driven by a circadian clock promoter. Conclusions The Agrobacterium infiltration assay developed here is a simple and enhanced throughput method that requires minimum handling and short transgenic process. This method will facilitate functional analyses of Populus genes in a homologous plant system.

  9. Genetic diversity in Populus nigra plantations from west of Iran

    Directory of Open Access Journals (Sweden)

    Afrooz Alimohamadi

    2012-11-01

    Full Text Available In order to adopt strategies for forest conservation and development,it is necessary to estimate the amount and distribution of genetic diversity in existing populations of poplar in Iran. In this study, the genetic diversity between eight stands of Populus nigra established in Kermanshah province was evaluated on the basis of molecular and morphological markers. To amplify microsatellite loci (WPMS09, WPMS16 and WPMS18, DNA extraction from young and fresh leaveswas done. Various conditions of the PCR assay were examined and to evaluate the morphological variation of the morphological characters leaves (consist of 19 traits were measured. In addition, height growth was measured, to evaluate the growth function of the stands in homogeneous conditions. Genetic diversity in termof polymorphic loci was 0%, because three investigated microsatellite loci were monomorphic. The total number of alleles for 3 microsatellite loci was 6 (na = 2, ne = 2, heo = 1, hee = 0.51. Genetic identity based on Nei was 100%, so genetic distance was 0%. The whole sampled trees represented the same thus the genotype. No significant differences between the mean values of all morphological characters and height growth were revealed. Observed genetic similarity gave indication that same ramets had been selected to plant in poplar plantation established in Kermanshah province.These results suggest the need for an initial evaluation of the genetic diversity in selected ramets for planting in plantation to avoid repetition.

  10. Genetic diversity in Populus nigra plantations from west of Iran

    Directory of Open Access Journals (Sweden)

    Afrooz Alimohamadi

    2012-12-01

    Full Text Available In order to adopt strategies for forest conservation and development, it is necessary to estimate the amount and distribution of genetic diversity in existing populations of poplar in Iran. In this study, the genetic diversity between eight stands of Populus nigra established in Kermanshah province was evaluated on the basis of molecular and morphological markers. To amplify microsatellite loci (WPMS09, WPMS16 and WPMS18, DNA extraction from young and fresh leaveswas done. Various conditions of the PCR assay were examined and to evaluate the morphological variation of the morphological characters leaves (consist of 19 traits were measured. In addition, height growth was measured, to evaluate the growth function of the stands in homogeneous conditions. Genetic diversity in term of polymorphic loci was 0%, because three investigated microsatellite loci were monomorphic. The total number of alleles for 3 microsatellite loci was 6 (na = 2, ne = 2, heo = 1, hee = 0.51. Genetic identity based on Nei was 100%, so genetic distance was 0%. The whole sampled trees represented the same thus the genotype. No significant differences between the mean values of all morphological characters and height growth were revealed. Observed genetic similarity gave indication that same ramets had been selected to plant in poplar plantation established in Kermanshah province. These results suggest the need for an initial evaluation of the genetic diversity in selected ramets for planting in plantation to avoid repetition.  

  11. Efficient Agrobacterium-mediated transformation of commercial hybrid poplar Populus nigra L. x P. maximowiczii A. Henry.

    Science.gov (United States)

    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.

  12. Degradation of Populus euphratica community in the lower reaches of the Tarim River, Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    LIU Jia-zhen; CHEN Ya-ning; CHEN Yong-jin; ZHANG Na; LI Wei-hong

    2005-01-01

    To investigate the relationships between the degradation of plant community and groundwater level in the lower reaches of the Tarim River, nine monitored sections were set along the main stream, where there had been no runoff for nearly 30 years. The characteristics of plant communities were analyzed. It was found that the coverage of trees gradually decreased along the groundwater depth gradient, while the coverage of shrubs slightly increased rather than decreased at first and then gradually decreased, and the coverage of herbs steadily decreased at the beginning and then quickly decreased. The species diversity and species richness of both herbs and woody plants showed obvious degrading trends, while the variations in species evenness were slight. The degrading sequences of species were related to their physiological and ecological characteristics, especially their sensitivity to changes of groundwater table. The herbs with shallow roots first degenerated or disappeared when the groundwater table fell, and then did the deep-rooted herbs, and finally the trees and shrubs with strong tolerance to drought degenerated. The Populus euphratica communities showed typical degrading characteristics, namely the dominant species Populus euphratica remained its dominant status during the degradation. Overall, the existence of strongly tolerant-drought species was the obvious indication of plant species degradation; while simplification of community structure and the decrease of species richness were the obvious indication of plant community degradation.

  13. Gene Response to Salt Stress in Populus euphratica

    Institute of Scientific and Technical Information of China (English)

    Shen Xin; Thomas Teichmenn; Wang Yiqin; Bai Genben; Yu Guangjun; Wang Shasheng

    2003-01-01

    Through construction of a subtracted cDNA library and library screening, a number of salt-induced cDNA fragmentshave been cloned from Populus euphratica. Based on the results of DNA sequencing and Northern analysis, the gene response ofPopulus euphratica to salt stress is discussed. It is indicated that in response to salt treatment the transcription level for some genes ofPopulus euphratica increases by about 1.5 times and significant difference between the responses to osmotic stress and to ion stresshas been observed in gene activity.

  14. The genome sequence of the North-European cucumber (Cucumis sativus L.) unravels evolutionary adaptation mechanisms in plants.

    Science.gov (United States)

    Wóycicki, Rafał; Witkowicz, Justyna; Gawroński, Piotr; Dąbrowska, Joanna; Lomsadze, Alexandre; Pawełkowicz, Magdalena; Siedlecka, Ewa; Yagi, Kohei; Pląder, Wojciech; Seroczyńska, Anna; Śmiech, Mieczysław; Gutman, Wojciech; Niemirowicz-Szczytt, Katarzyna; Bartoszewski, Grzegorz; Tagashira, Norikazu; Hoshi, Yoshikazu; Borodovsky, Mark; Karpiński, Stanisław; Malepszy, Stefan; Przybecki, Zbigniew

    2011-01-01

    Cucumber (Cucumis sativus L.), a widely cultivated crop, has originated from Eastern Himalayas and secondary domestication regions includes highly divergent climate conditions e.g. temperate and subtropical. We wanted to uncover adaptive genome differences between the cucumber cultivars and what sort of evolutionary molecular mechanisms regulate genetic adaptation of plants to different ecosystems and organism biodiversity. Here we present the draft genome sequence of the Cucumis sativus genome of the North-European Borszczagowski cultivar (line B10) and comparative genomics studies with the known genomes of: C. sativus (Chinese cultivar--Chinese Long (line 9930)), Arabidopsis thaliana, Populus trichocarpa and Oryza sativa. Cucumber genomes show extensive chromosomal rearrangements, distinct differences in quantity of the particular genes (e.g. involved in photosynthesis, respiration, sugar metabolism, chlorophyll degradation, regulation of gene expression, photooxidative stress tolerance, higher non-optimal temperatures tolerance and ammonium ion assimilation) as well as in distributions of abscisic acid-, dehydration- and ethylene-responsive cis-regulatory elements (CREs) in promoters of orthologous group of genes, which lead to the specific adaptation features. Abscisic acid treatment of non-acclimated Arabidopsis and C. sativus seedlings induced moderate freezing tolerance in Arabidopsis but not in C. sativus. This experiment together with analysis of abscisic acid-specific CRE distributions give a clue why C. sativus is much more susceptible to moderate freezing stresses than A. thaliana. Comparative analysis of all the five genomes showed that, each species and/or cultivars has a specific profile of CRE content in promoters of orthologous genes. Our results constitute the substantial and original resource for the basic and applied research on environmental adaptations of plants, which could facilitate creation of new crops with improved growth and yield in

  15. The genome sequence of the North-European cucumber (Cucumis sativus L. unravels evolutionary adaptation mechanisms in plants.

    Directory of Open Access Journals (Sweden)

    Rafał Wóycicki

    Full Text Available Cucumber (Cucumis sativus L., a widely cultivated crop, has originated from Eastern Himalayas and secondary domestication regions includes highly divergent climate conditions e.g. temperate and subtropical. We wanted to uncover adaptive genome differences between the cucumber cultivars and what sort of evolutionary molecular mechanisms regulate genetic adaptation of plants to different ecosystems and organism biodiversity. Here we present the draft genome sequence of the Cucumis sativus genome of the North-European Borszczagowski cultivar (line B10 and comparative genomics studies with the known genomes of: C. sativus (Chinese cultivar--Chinese Long (line 9930, Arabidopsis thaliana, Populus trichocarpa and Oryza sativa. Cucumber genomes show extensive chromosomal rearrangements, distinct differences in quantity of the particular genes (e.g. involved in photosynthesis, respiration, sugar metabolism, chlorophyll degradation, regulation of gene expression, photooxidative stress tolerance, higher non-optimal temperatures tolerance and ammonium ion assimilation as well as in distributions of abscisic acid-, dehydration- and ethylene-responsive cis-regulatory elements (CREs in promoters of orthologous group of genes, which lead to the specific adaptation features. Abscisic acid treatment of non-acclimated Arabidopsis and C. sativus seedlings induced moderate freezing tolerance in Arabidopsis but not in C. sativus. This experiment together with analysis of abscisic acid-specific CRE distributions give a clue why C. sativus is much more susceptible to moderate freezing stresses than A. thaliana. Comparative analysis of all the five genomes showed that, each species and/or cultivars has a specific profile of CRE content in promoters of orthologous genes. Our results constitute the substantial and original resource for the basic and applied research on environmental adaptations of plants, which could facilitate creation of new crops with improved growth

  16. 胡杨谷胱甘肽过氧化物酶PeGPX基因的克隆及转化植株耐盐性分析%Cloning of Glutathione Peroxidase Gene PeGPX from Populus euphratica and the Salt Tolerance of the Transformed Plants

    Institute of Scientific and Technical Information of China (English)

    王菲菲; 沈昕; 陈少良; 丁明全; 邓澍荣; 王美娟; 孙健; 侯佩臣; 马旭君; 张玉红; 赵楠

    2012-01-01

    胡杨(Populus euphratica Oliv.)具有极强抗盐碱能力.本实验室前期胡杨微阵列芯片数据结果显示:盐胁迫下,胡杨谷胱甘肽过氧化物酶基因(PeGPX)的转录上调,暗示该基因可能对胡杨耐盐性具有一定的作用.为分析GPX对植物耐盐性的贡献,本研究以胡杨为材料,利用RT-PCR方法克隆了胡杨谷胱甘肽过氧化物酶PeGPX基因,并在烟草中过量表达该基因,以分析谷胱甘肽过氧化物酶活性与植物耐盐性的关系.研究结果显示,实验中克隆的cDNA (PeGPX)编码谷胱甘肽过氧化物酶,其ORF为693 bp,其蛋白由231个氨基酸编码.过量表达PeGPX基因的烟草与野生型烟草的耐盐性实验结果显示,野生型烟草植株在加NaCl (200 mmol/L)的MS培养基中生长15 d后,无明显的长高,且不长根;而转基因烟草在同样的加盐培养基上,生长基本没有受到抑制,植株生长状态良好,并且能够长根.光合数据显示,在盐胁迫下过量表达PeGPX基因烟草的净光合速率受到影响明显小于野生型烟草的净光合速率.酶活数据显示,转基因株系GPX酶活与野生型的相比在盐胁迫下活性有非常显著的提高.我们的研究结果说明:过表达PeGPX基因使得烟草的耐盐性得到显著提高,这对深入研究PeGPX基因在胡杨耐盐机制中的作用具有重要的意义.%Populus euphratica has a high capacity to tolerate salinity. Previous transcriptomic analysis of P. euphratica shows that glutathione peroxidase gene (PeGPX) is up-regulated under salt stress. That indicates PeGPX enzyme may play an important role in salt tolerance off. euphratica. To analyze the functions of PeGPX in salinity tolerance, we cloned the full length cDNA of PeGPX from P. euphratica, and the PeGPX gene was overexpressed into tobacco plants to analyze its contribution to salt tolerance. Blast analysis shows that the cloned cDNA encodes Glutathione peroxidase, which is a hydrophobic protein of 231 amino acids

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

    Science.gov (United States)

    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.

  18. Widespread triploidy in Western North American aspen (Populus tremuloides).

    Science.gov (United States)

    Mock, Karen E; Callahan, Colin M; Islam-Faridi, M Nurul; Shaw, John D; Rai, Hardeep S; Sanderson, Stewart C; Rowe, Carol A; Ryel, Ronald J; Madritch, Michael D; Gardner, Richard S; Wolf, Paul G

    2012-01-01

    We document high rates of triploidy in aspen (Populus tremuloides) across the western USA (up to 69% of genets), and ask whether the incidence of triploidy across the species range corresponds with latitude, glacial history (as has been documented in other species), climate, or regional variance in clone size. Using a combination of microsatellite genotyping, flow cytometry, and cytology, we demonstrate that triploidy is highest in unglaciated, drought-prone regions of North America, where the largest clone sizes have been reported for this species. While we cannot completely rule out a low incidence of undetected aneuploidy, tetraploidy or duplicated loci, our evidence suggests that these phenomena are unlikely to be significant contributors to our observed patterns. We suggest that the distribution of triploid aspen is due to a positive synergy between triploidy and ecological factors driving clonality. Although triploids are expected to have low fertility, they are hypothesized to be an evolutionary link to sexual tetraploidy. Thus, interactions between clonality and polyploidy may be a broadly important component of geographic speciation patterns in perennial plants. Further, cytotypes are expected to show physiological and structural differences which may influence susceptibility to ecological factors such as drought, and we suggest that cytotype may be a significant and previously overlooked factor in recent patterns of high aspen mortality in the southwestern portion of the species range. Finally, triploidy should be carefully considered as a source of variance in genomic and ecological studies of aspen, particularly in western U.S. landscapes.

  19. Widespread triploidy in Western North American aspen (Populus tremuloides.

    Directory of Open Access Journals (Sweden)

    Karen E Mock

    Full Text Available We document high rates of triploidy in aspen (Populus tremuloides across the western USA (up to 69% of genets, and ask whether the incidence of triploidy across the species range corresponds with latitude, glacial history (as has been documented in other species, climate, or regional variance in clone size. Using a combination of microsatellite genotyping, flow cytometry, and cytology, we demonstrate that triploidy is highest in unglaciated, drought-prone regions of North America, where the largest clone sizes have been reported for this species. While we cannot completely rule out a low incidence of undetected aneuploidy, tetraploidy or duplicated loci, our evidence suggests that these phenomena are unlikely to be significant contributors to our observed patterns. We suggest that the distribution of triploid aspen is due to a positive synergy between triploidy and ecological factors driving clonality. Although triploids are expected to have low fertility, they are hypothesized to be an evolutionary link to sexual tetraploidy. Thus, interactions between clonality and polyploidy may be a broadly important component of geographic speciation patterns in perennial plants. Further, cytotypes are expected to show physiological and structural differences which may influence susceptibility to ecological factors such as drought, and we suggest that cytotype may be a significant and previously overlooked factor in recent patterns of high aspen mortality in the southwestern portion of the species range. Finally, triploidy should be carefully considered as a source of variance in genomic and ecological studies of aspen, particularly in western U.S. landscapes.

  20. Metabolic profiling reveals altered sugar and secondary metabolism in response to UGPase overexpression in Populus

    OpenAIRE

    2014-01-01

    Background UDP-glucose pyrophosphorylase (UGPase) is a sugar-metabolizing enzyme (E.C. 2.7.7.9) that catalyzes a reversible reaction of UDP-glucose and pyrophosphate from glucose-1-phosphate and UTP. UDP-glucose is a key intermediate sugar that is channeled to multiple metabolic pathways. The functional role of UGPase in perennial woody plants is poorly understood. Results We characterized the functional role of a UGPase gene in Populus deltoides, PdUGPase2. Overexpression of the native gene ...

  1. Arsenic tolerance and phytoremediation potential of Conocarpus erectus L. and Populus deltoides L.

    Science.gov (United States)

    Hussain, Sajad; Akram, Muhammad; Abbas, Ghulam; Murtaza, Behzad; Shahid, Muhammad; Shah, Noor S; Bibi, Irshad; Niazi, Nabeel Khan

    2017-03-21

    The present study was conducted to explore arsenic (As) tolerance and phytostabilization potential of the two tree species, Buttonwood (Conocarpus erectus) and Eastern cottonwood (Populus deltoides). Both plant species were exposed to various soil As levels (control, 5, 10, 15 and 20 mg kg(-1)) in pots. The plants were harvested after nine months for evaluation of growth parameters as well as root and shoot As concentrations. With increasing soil As levels, plant height stress tolerance index (PHSTI) was significantly decreased in both tree species, whereas root length stress tolerance index (RLSTI) and dry matter stress tolerance index (DMSTI) were not affected. Root and shoot As concentrations significantly increased in both tree species with increasing soil As levels. Translocation factor and bioconcentration factor were less than 1.0 for both plant species. This study revealed that both tree species are non-hyperaccumulators of As, but could be used for phytostabilization of As-contaminated soils.

  2. Chemical responses to modified lignin composition in tension wood of hybrid poplar (Populus tremula x Populus alba).

    Science.gov (United States)

    Al-Haddad, Jameel M; Kang, Kyu-Young; Mansfield, Shawn D; Telewski, Frank W

    2013-04-01

    The effect of altering the expression level of the F5H gene was investigated in three wood tissues (normal, opposite and tension wood) in 1-year-old hybrid poplar clone 717 (Populus tremula × Populus alba L.), containing the F5H gene under the control of the C4H promoter. Elevated expression of the F5H gene in poplar has been previously reported to increase the percent syringyl content of lignin. The wild-type and three transgenic lines were inclined 45° for 3 months to induce tension wood formation. Tension and opposite wood from inclined trees, along with normal wood from control trees, were analyzed separately for carbohydrates, lignin, cellulose crystallinity and microfibril angle (MFA). In the wild-type poplar, the lignin in tension wood contained a significantly higher percentage of syringyl than normal wood or opposite wood. However, there was no significant difference in the percent syringyl content of the three wood types within each of the transgenic lines. Increasing the F5H gene expression caused an increase in the percent syringyl content and a slight decrease in the total lignin in normal wood. In tension wood, the addition of a gelatinous layer in the fiber walls resulted in a consistently lower percentage of total lignin in the tissue. Acid-soluble lignin was observed to increase by up to 2.3-fold in the transgenic lines. Compared with normal wood and opposite wood, cell wall crystallinity in tension wood was higher and the MFA was smaller, as expected, with no evidence of an effect from modifying the syringyl monomer ratio. Tension wood in all the lines contained consistently higher total sugar and glucose percentages when compared with normal wood within the respective lines. However, both sugar and glucose percentages were lower in the tension wood of transgenic lines when compared with the tension wood of wild-type trees. Evaluating the response of trees with altered syringyl content to gravity will improve our understanding of the changes

  3. Protein (Viridiplantae): 224147325 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 5294 3694:5294 predicted protein, partial Populus trichocarpa GLCARTKPSFSWGSGFRDDFQVGNDLVFGDDYRVNKDYRVNRDYYR...VNKDCERIRNKASAGEAVLSTISKAAATLFSVTITESLGIGLCARTKPSFSWGSSFGDDFQVGSDYVFGDDYRVNSDSGVN...RTVRAYGTKNHLGKRFCLQFPSRQRLSFGSRLPSEQGLCAQTKPGISWGSSSGDDFRGGRDSLSGLCARTKPSFSWGSGFRNDFQVGSDLVFGDDYRVNRDYRVNRDY...YRVNKDCARIRNKVISWGSGFVDNFQGGSDSVFGDDYRVNMDCAHRQNQASAGEAVLGLCARTKPSFSWGSGFRDDFQVGS...DLVFGADYRVNRDYRVNRDYYRVNKDCACIRNKASAGEAVSSKISKSAATLFSVTITESIGIVRTDNSRHQLGKQFCQQGLCARTKPSFSWGSGFRNDFQVGSDLVFGDDYRVNRDYRVNRDYYRVNKDCARIRNKASAGEAVSSTISKSAATLFSVTITESLGIVRIDNSTHQLGKKFW ...

  4. Protein (Viridiplantae): 224086357 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 4:195 predicted protein Populus trichocarpa MATTLKSLSSFVILLIVNSLFFTGTTEARPFNIMKSGNSAASRGTESFFDGLSLGGIKEGPSPGAGHEFTNSGTL...GGIKEEGPSPSAGHGFTSSGTLGGIKEGPSPGAGHGFTNSGTLGGIKEGPSPGVGHGFTNSGTLEGIKKEGPSPTNSGTL...GGIKEGPSPGAGHGFTNSETLGGIKEGPSPGVGHEFTNSGTLGGIKEGPSPGVGHGFTNSGTLEGIKKEGPSPTNSGTLGGIKEGPSPGAGHGFTNSE...TLGGIKEGPSPGGIKEGSSPGVGHAFTNSGTLGGIKEGPSPGAGHAFTNSGTLGGIKEGPSPGAGHGFTNSGTLGGIKEGSSPGVGHGFTNSGTLGGIKEGPSPCCGNKYTTGTKH ...

  5. Protein (Viridiplantae): 224124826 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 94:2255 predicted protein Populus trichocarpa MQLLDLEEDGSASLFIEKSAAKTASLPISASAAKTASLPISASAAKTAWLPIKKWAAKTVSL...PISVSVVKAASLPSPESAAKTASLLISASAAKTASLPSPESAAKTASLPSPESAAKTASLPISASVDKTASMPSPESAAKTASLPSSESAAKTASLPISA...SAAKTASLPSPESAAKTASLPISASADKTASMPSPESAAKTASLPSPESAAKTASLPISASAAKTASLPSPESAAKTASLPISASADKT...ASMPSPESAAKTASLPSPESAAKTASLPISASAAKTASLPSPESAAKTASLPSPESAANTASLPISASAAKTASLPISASAAKTASLPISASAAKTAFIIISLSLNIYIYFPLGVYK ...

  6. Diversity of Pseudomonas Genomes, Including Populus-Associated Isolates, as Revealed by Comparative Genome Analysis.

    Science.gov (United States)

    Jun, Se-Ran; Wassenaar, Trudy M; Nookaew, Intawat; Hauser, Loren; Wanchai, Visanu; Land, Miriam; Timm, Collin M; Lu, Tse-Yuan S; Schadt, Christopher W; Doktycz, Mitchel J; Pelletier, Dale A; Ussery, David W

    2015-10-30

    The Pseudomonas genus contains a metabolically versatile group of organisms that are known to occupy numerous ecological niches, including the rhizosphere and endosphere of many plants. Their diversity influences the phylogenetic diversity and heterogeneity of these communities. On the basis of average amino acid identity, comparative genome analysis of >1,000 Pseudomonas genomes, including 21 Pseudomonas strains isolated from the roots of native Populus deltoides (eastern cottonwood) trees resulted in consistent and robust genomic clusters with phylogenetic homogeneity. All Pseudomonas aeruginosa genomes clustered together, and these were clearly distinct from other Pseudomonas species groups on the basis of pangenome and core genome analyses. In contrast, the genomes of Pseudomonas fluorescens were organized into 20 distinct genomic clusters, representing enormous diversity and heterogeneity. Most of our 21 Populus-associated isolates formed three distinct subgroups within the major P. fluorescens group, supported by pathway profile analysis, while two isolates were more closely related to Pseudomonas chlororaphis and Pseudomonas putida. Genes specific to Populus-associated subgroups were identified. Genes specific to subgroup 1 include several sensory systems that act in two-component signal transduction, a TonB-dependent receptor, and a phosphorelay sensor. Genes specific to subgroup 2 contain hypothetical genes, and genes specific to subgroup 3 were annotated with hydrolase activity. This study justifies the need to sequence multiple isolates, especially from P. fluorescens, which displays the most genetic variation, in order to study functional capabilities from a pangenomic perspective. This information will prove useful when choosing Pseudomonas strains for use to promote growth and increase disease resistance in plants.

  7. The polyphenol oxidase gene family in land plants: Lineage-specific duplication and expansion

    Directory of Open Access Journals (Sweden)

    Tran Lan T

    2012-08-01

    Full Text Available Abstract Background Plant polyphenol oxidases (PPOs are enzymes that typically use molecular oxygen to oxidize ortho-diphenols to ortho-quinones. These commonly cause browning reactions following tissue damage, and may be important in plant defense. Some PPOs function as hydroxylases or in cross-linking reactions, but in most plants their physiological roles are not known. To better understand the importance of PPOs in the plant kingdom, we surveyed PPO gene families in 25 sequenced genomes from chlorophytes, bryophytes, lycophytes, and flowering plants. The PPO genes were then analyzed in silico for gene structure, phylogenetic relationships, and targeting signals. Results Many previously uncharacterized PPO genes were uncovered. The moss, Physcomitrella patens, contained 13 PPO genes and Selaginella moellendorffii (spike moss and Glycine max (soybean each had 11 genes. Populus trichocarpa (poplar contained a highly diversified gene family with 11 PPO genes, but several flowering plants had only a single PPO gene. By contrast, no PPO-like sequences were identified in several chlorophyte (green algae genomes or Arabidopsis (A. lyrata and A. thaliana. We found that many PPOs contained one or two introns often near the 3’ terminus. Furthermore, N-terminal amino acid sequence analysis using ChloroP and TargetP 1.1 predicted that several putative PPOs are synthesized via the secretory pathway, a unique finding as most PPOs are predicted to be chloroplast proteins. Phylogenetic reconstruction of these sequences revealed that large PPO gene repertoires in some species are mostly a consequence of independent bursts of gene duplication, while the lineage leading to Arabidopsis must have lost all PPO genes. Conclusion Our survey identified PPOs in gene families of varying sizes in all land plants except in the genus Arabidopsis. While we found variation in intron numbers and positions, overall PPO gene structure is congruent with the phylogenetic

  8. Phylogenetic analysis, subcellular localization, and expression patterns of RPD3/HDA1 family histone deacetylases in plants

    Directory of Open Access Journals (Sweden)

    Yu Chun-Wei

    2009-03-01

    Full Text Available Abstract Background Although histone deacetylases from model organisms have been previously identified, there is no clear basis for the classification of histone deacetylases under the RPD3/HDA1 superfamily, particularly on plants. Thus, this study aims to reconstruct a phylogenetic tree to determine evolutionary relationships between RPD3/HDA1 histone deacetylases from six different plants representing dicots with Arabidopsis thaliana, Populus trichocarpa, and Pinus taeda, monocots with Oryza sativa and Zea mays, and the lower plants with Physcomitrella patens. Results Sixty two histone deacetylases of RPD3/HDA1 family from the six plant species were phylogenetically analyzed to determine corresponding orthologues. Three clusters were formed separating Class I, Class II, and Class IV. We have confirmed lower and higher plant orthologues for AtHDA8 and AtHDA14, classifying both genes as Class II histone deacetylases in addition to AtHDA5, AtHDA15, and AtHDA18. Since Class II histone deacetylases in other eukaryotes have been known to undergo nucleocytoplasmic transport, it remains unknown whether such functional regulation also happens in plants. Thus, bioinformatics studies using different programs and databases were conducted to predict their corresponding localization sites, nuclear export signal, nuclear localization signal, as well as expression patterns. We also found new conserved domains in most of the RPD3/HDA1 histone deacetylases which were similarly conserved in its corresponding orthologues. Assessing gene expression patterns using Genevestigator, it appears that RPD3/HDA1 histone deacetylases are expressed all throughout the plant parts and developmental stages of the plant. Conclusion The RPD3/HDA1 histone deacetylase family in plants is divided into three distinct groups namely, Class I, Class II, and Class IV suggesting functional diversification. Class II comprises not only AtHDA5, AtHDA15, and AtHDA18 but also includes AtHDA8

  9. Rooting greenwood tip cuttings of several Populus clones hydroponically (hydroponic rooting of Populus cuttings)

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, H.M.; Hansen, E.A.; Tolsted, D.N.

    1980-01-01

    Greenwood cuttings of several Populus clones were successfully rooted with a relatively simple hydroponic method. Indolebutyric acid and naphthaleneacetic acid at concentrations of 500 to 5000 ppM applied as a quick dip to the cutting bases, a complete nutrient solution at 20 to 40% of full strength, and a solution temperature between 27 and 30/sup 0/C generally produced the best rooting performance of most clones. Cuttings propagated by the hydroponic procedure rooted faster and generally outgrew those produced by a standard method after being transplanted to pots and grown in the greenhouse.

  10. Newly identified helper bacteria stimulate ectomycorrhizal formation in Populus.

    Science.gov (United States)

    Labbé, Jessy L; Weston, David J; Dunkirk, Nora; Pelletier, Dale A; Tuskan, Gerald A

    2014-01-01

    Mycorrhiza helper bacteria (MHB) are known to increase host root colonization by mycorrhizal fungi but the molecular mechanisms and potential tripartite interactions are poorly understood. Through an effort to study Populus microbiome, we isolated 21 Pseudomonas strains from native Populus deltoides roots. These bacterial isolates were characterized and screened for MHB effectiveness on the Populus-Laccaria system. Two additional Pseudomonas strains (i.e., Pf-5 and BBc6R8) from existing collections were included for comparative purposes. We analyzed the effect of co-cultivation of these 23 individual Pseudomonas strains on Laccaria bicolor "S238N" growth rate, mycelial architecture and transcriptional changes. Nineteen of the 23 Pseudomonas strains tested had positive effects on L. bicolor S238N growth, as well as on mycelial architecture, with strains GM41 and GM18 having the most significant effect. Four of seven L. bicolor reporter genes, Tra1, Tectonin2, Gcn5, and Cipc1, thought to be regulated during the interaction with MHB strain BBc6R8, were induced or repressed, while interacting with Pseudomonas strains GM17, GM33, GM41, GM48, Pf-5, and BBc6R8. Strain GM41 promoted the highest roots colonization across three Populus species but most notably in P. deltoides, which is otherwise poorly colonized by L. bicolor. Here we report novel MHB strains isolated from native Populus that improve L. bicolor root colonization on Populus. This tripartite relationship could be exploited for Populus species/genotypes nursery production as a means of improving establishment and survival in marginal lands.

  11. Newly identified helper bacteria stimulate ectomycorrhizal formation in Populus

    Directory of Open Access Journals (Sweden)

    Jessy L Labbé

    2014-10-01

    Full Text Available Mycorrhiza helper bacteria (MHB are known to increase host root colonization by mycorrhizal fungi but the molecular mechanisms and potential tripartite interactions are poorly understood. Through an effort to study Populus microbiome, we isolated 21 Pseudomonas strains from native Populus deltoides roots. These bacterial isolates were characterized and screened for MHB effectiveness on the Populus-Laccaria system. Two additional Pseudomonas strains (i.e., Pf-5 and BBc6R8 from existing collections were included for comparative purposes. We analyzed the effect of co-cultivation of these 23 individual Pseudomonas strains on Laccaria bicolor ‘S238N’ growth rate, mycelial architecture and transcriptional changes. Nineteen of the 23 Pseudomonas strains tested had positive effects on L. bicolor S238N growth, as well as on mycelial architecture, with strains GM41 and GM18 having the most significant effect. Four of seven L. bicolor reporter genes, Tra1, Tectonin2, Gcn5 and Cipc1, thought to be regulated during the interaction with MHB strain BBc6R8, were induced or repressed, while interacting with Pseudomonas strains GM17, GM33, GM41, GM48, Pf-5 and BBc6R8. Strain GM41 promoted the highest roots colonization across three Populus species but most notably in P. deltoides, which is otherwise poorly colonized by L. bicolor. Here we report novel MHB strains isolated from native Populus that improve L. bicolor root colonization on Populus. This tripartite relationship could be exploited for Populus species/genotypes nursery production as a means of improving establishment and survival in marginal lands.

  12. Electroantennogram responses of Clostera anastomosis adults to plant vola-tile of Populus nigra%分月扇舟蛾成虫对黑杨挥发物的触角电位反应

    Institute of Scientific and Technical Information of China (English)

    凌娜; 唐进根; 殷玉生; 张帆; 安榆林

    2014-01-01

    为给植物挥发物引诱剂的开发提供理论依据和基础资料,选取了分月扇舟蛾( Clostera anastomosis)和黑杨为试验对象,利用触角电位技术测试了分月扇舟蛾成虫对11种杨树叶片挥发物及其混配物的触角电位反应。结果表明,雌虫与雄虫触角对杨树挥发物的触角电位( EAG)反应没有显著差异;成虫交配前后触角对杨树挥发物的EAG反应同样没有显著差异。将不同化合物进行混配发现,邻羟基苯甲醛、顺-3-己烯醇和丁(子)香酚相互混配时可增强分月扇舟蛾的触角电位活性。通过测定5种挥发物的5种浓度梯度的触角电位活性,发现成虫对混合物的触角电位反应相对值开始随着化合物浓度的升高而升高,但到达一定浓度后,触角电位反应相对值随着浓度的升高而降低。%To provide theoretical basis and information for development of herbivore-induced plant volatiles as at-tractants, Clostera anastomosis were selected to detect the antennal electrophysiological responses to 11 plant volatiles from poplar leaf revealed by electroantennogram ( EAG) . The female and male adults gave similar EAG responses to poplar vola-tiles, and the EAG response of the antennae of adults before and after mating was consistent. The antennal activity of C. anastomosis be enhanced by the mixture of three volatiles, salicylaldehyde, cis-3-hexenol and eugenol. By measurement of the antennl electrophysiological activities of C. anastomosis in response to 5 concentration gradients of 5 volatiles, an in-crease of relative value of EAG response of adults to the mixtures was found as a function of increase in the concentration of the mixture at the beginning, but decreased after wards.

  13. NCBI nr-aa BLAST: CBRC-TTRU-01-0827 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-TTRU-01-0827 ref|XP_002298442.1| predicted protein [Populus trichocarpa] gb|AB...K94884.1| unknown [Populus trichocarpa] gb|EEE83247.1| predicted protein [Populus trichocarpa] XP_002298442.1 1.8 28% ...

  14. Field Supervisory Test of DREB-Transgenic Populus: Salt Tolerance, Long-Term Gene Stability and Horizontal Gene Transfer

    Directory of Open Access Journals (Sweden)

    Nan Lu

    2014-05-01

    Full Text Available Improving saline resistance may be useful for reducing environmental susceptibility and improving yields in poplar plantations. However, the instability of genetically engineered traits and gene transfer reduce their usefulness and commercial value. To investigate whether the foreign gene is still present in the genome of receptor plants after seven years (i.e., long-term foreign gene stability and gene transfer, we randomly analyzed ten field-grown transgenic hybrid Populus ((Populus tomentosa × Populus bolleana × P. tomentosa carrying the DREB1 gene from Atriplex hortensis. The results of PCR and tissue culture experiments showed that AhDREB1 was present in the transgenic trees and was still expressed. However, the transcriptional expression level had decreased compared with that four years earlier. The PCR results also indicated no foreign gene in the genomic DNA of microorganisms in the soil near the transgenic poplars, indicating that no significant gene transfer had occurred from the transgenic poplars to the microorganisms at seven years after planting.

  15. Geochemical peculiarities of black poplar leaves (Populus nigra L.) in the sites with heavy metals intensive fallouts

    Science.gov (United States)

    Yalaltdinova, Albina; Baranovskaya, Natalya; Rikhvanov, Leonid; Matveenko, Irina

    2013-04-01

    The article deals with the content of 28 chemical elements in the leaves ash of black poplar (Populus nigra L.) growing in Ust-Kamenogorsk city area. It is the major industrial center of Kazakhstan Republic on the territory where the industrial giants of non-ferrous metallurgy and nuclear energy are situated. Comparative analysis with the similar data obtained from leaves ash of Populus nigra L. in Tomsk, Ekibastuz, and Pavlodar cities has revealed that in comparison with other urban areas, leaves ash of black poplar (Populus nigra L.) from Ust-Kamenogorsk city is characterized by elevated concentration rates of Ta, U, Zn, Ag, As, Sb, Br, Sr and Na. Within the city, the sites and areas with abnormal contents of typomorphic pollutants have been revealed. In the central part of the city, in the vicinity of lead-zinc plant and Ulba metallurgical plant, the highest concentrations of Ta, U, Zn, Ag, Au, As, Sb, Cr and Fe were marked. In the northeast, where the titanium-magnesium plant is located, elevated concentrations of Br and Sr were stated. Thus, the impact of major city enterprises which are the main sources of heavy metals is reflected in the element composition. Zn, As, Sb, Ag and Au comes from lead-zinc plant and its refinery plants, while Ulba metallurgical plant can be considered source of Ta and U in the environment, producing tantalum and fuel pellets for nuclear power plants. These companies, due to the current objective circumstances, are located in the central part of the city, have a significant negative effect on the environment and form the risk factors for human health.

  16. Repeated unidirectional introgression towards Populus balsamifera in contact zones of exotic and native poplars

    NARCIS (Netherlands)

    Thompson, S.L.; Lamothe, M.; Meirmans, P.G.; Périnet, P.; Isabel, N.

    2010-01-01

    As the evolutionary significance of hybridization is largely dictated by its extent beyond the first generation, we broadly surveyed patterns of introgression across a sympatric zone of two native poplars (Populus balsamifera, Populus deltoides) in Quebec, Canada within which European exotic Populus

  17. Down-Regulation of KORRIGAN-Like Endo-β-1,4-Glucanase Genes Impacts Carbon Partitioning, Mycorrhizal Colonization and Biomass Production in Populus

    OpenAIRE

    2016-01-01

    A greater understanding of the genetic regulation of plant cell wall remodeling and the impact of modified cell walls on plant performance is important for the development of sustainable biofuel crops. Here, we studied the impact of down-regulating KORRIGAN-like cell wall biosynthesis genes, belonging to the endo-β-1,4-glucanase gene family, on Populus growth, metabolism and the ability to interact with symbiotic microbes. The reductions in cellulose content and lignin syringyl-to-guaiacyl un...

  18. Down-regulation of KORRIGAN-like endo-β-1,4-glucanase genes impacts carbon partitioning, mycorrhizal colonization and biomass production in Populus

    OpenAIRE

    2016-01-01

    A greater understanding of the genetic regulation of plant cell wall remodeling and the impact of modified cell walls on plant performance is important for the development of sustainable biofuel crops. Here, we studied the impact of down-regulating KORRIGAN-like cell wall biosynthesis genes, belonging to the endo-β-1,4-glucanase gene family, on Populus growth, metabolism and the ability to interact with symbiotic microbes. The reductions in cellulose content and lignin syringyl-to-guaiacyl un...

  19. Interrelationships between leaf heat conductivity and tissue structures of different varieties of Populus tomentosa Carr.

    Institute of Scientific and Technical Information of China (English)

    WANG Min; ZHANG Wen-jie; XIAO Jian; ZHANG Zhi-yi; LIU Jing

    2008-01-01

    Plant heat conductivity largely depends on tissue structure. Different structures lead to different heat conductivity. As well, water transfer also plays a very important role in heat transfer in plants. We have studied leaf heat conductivity and tissue structure of 3- and 30-year-old Populus tomentosa Carr. trees using mildred thermal imaging, steady state heat conductivity surveys and paraffin section and investigated the relationship between leaf heat conductivity, tissue structure and water content of leaves. The results show that the temperature on leaf surfaces among the various varieties of trees was almost the same. Leaf heat conductivity, temperature and water content of leaves are positively correlated. The thicker the leaf tissue structures, the larger the heat resistance. That is, the tighter the cells and the smaller the interspaces, the smaller the heat conductivity, which is not conducive for heat transfer.

  20. Model of leaf energy distribution and its experimental validation of Populus tomentosa Carr

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wen-jie; WANG Min; SHEN Ying-bai; ZHANG Zhi-yi

    2008-01-01

    Leaf temperature of a plant is the result of heat transfer between the plant and its environment. There are many factors that can affect leaf temperature, such as the solar radiation energy, environmental temperature, wind velocity, evaporation on the leaf surface, photosynthesis, respiration and so on, which have different effects on the temperature of leaves. In first instance, we analyzed the heat transfer on leaves of Populus tomentosa Cart. theoretically and constructed a model of energy distribution. We then validated the model by analyzing seven different kinds of one-year-old P. tomentosa leaves experimentally. The result shows that solar radiation is the main energy input and the dominant ways of thermal diffusion are heat transfer between the upper and lower leaf surfaces and evaporation from the leaf surface.

  1. Genomics of Secondary Metabolism in Populus: Interactions with Biotic and Abiotic Environments

    Energy Technology Data Exchange (ETDEWEB)

    Chen, F.; Liu, C.; Tschaplinski, T. J.; Zhao, N.

    2009-09-01

    Populus trees face constant challenges from the environment during their life cycle. To ensure their survival and reproduction, Populus trees deploy various types of defenses, one of which is the production of a myriad of secondary metabolites. Compounds derived from the shikimate-phenylpropanoid pathway are the most abundant class of secondary metabolites synthesized in Populus. Among other major classes of secondary metabolites in Populus are terpenoids and fatty acid-derivatives. Some of the secondary metabolites made by Populus trees have been functionally characterized. Some others have been associated with certain biological/ecological processes, such as defense against insects and microbial pathogens or acclimation or adaptation to abiotic stresses. Functions of many Populus secondary metabolites remain unclear. The advent of various novel genomic tools will enable us to explore in greater detail the complexity of secondary metabolism in Populus. Detailed data mining of the Populus genome sequence can unveil candidate genes of secondary metabolism. Metabolomic analysis will continue to identify new metabolites synthesized in Populus. Integrated genomics that combines various 'omics' tools will prove to be the most powerful approach in revealing the molecular and biochemical basis underlying the biosynthesis of secondary metabolites in Populus. Characterization of the biological/ecological functions of secondary metabolites as well as their biosynthesis will provide knowledge and tools for genetically engineering the production of seconday metabolites that can lead to the generation of novel, improved Populus varieties.

  2. Salt stress induces the formation of a novel type of 'pressure wood' in two Populus species.

    Science.gov (United States)

    Janz, Dennis; Lautner, Silke; Wildhagen, Henning; Behnke, Katja; Schnitzler, Jörg-Peter; Rennenberg, Heinz; Fromm, Jörg; Polle, Andrea

    2012-04-01

    • Salinity causes osmotic stress and limits biomass production of plants. The goal of this study was to investigate mechanisms underlying hydraulic adaptation to salinity. • Anatomical, ecophysiological and transcriptional responses to salinity were investigated in the xylem of a salt-sensitive (Populus × canescens) and a salt-tolerant species (Populus euphratica). • Moderate salt stress, which suppressed but did not abolish photosynthesis and radial growth in P. × canescens, resulted in hydraulic adaptation by increased vessel frequencies and decreased vessel lumina. Transcript abundances of a suite of genes (FLA, COB-like, BAM, XET, etc.) previously shown to be activated during tension wood formation, were collectively suppressed in developing xylem, whereas those for stress and defense-related genes increased. A subset of cell wall-related genes was also suppressed in salt-exposed P. euphratica, although this species largely excluded sodium and showed no anatomical alterations. Salt exposure influenced cell wall composition involving increases in the lignin : carbohydrate ratio in both species. • In conclusion, hydraulic stress adaptation involves cell wall modifications reciprocal to tension wood formation that result in the formation of a novel type of reaction wood in upright stems named 'pressure wood'. Our data suggest that transcriptional co-regulation of a core set of genes determines reaction wood composition.

  3. Overexpression of phospholipase Dα gene enhances drought and salt tolerance of Populus tomentosa

    Institute of Scientific and Technical Information of China (English)

    ZHANG TingTing; SONG YunZhi; LIU YuDong; GUO XingQi; ZHU ChangXiang; WEN FuJiang

    2008-01-01

    The cDNA of AtPLDα (Arabidopsis thaliana Phospholipase Da) gene was introduced into P. tomentosa (Populus tomentosa) under the control of the Cauliflower mosaic virus 35S promoter. Southern and Northern blot analyses suggested that the AtPLDα gene has been transferred into the P. tomentosa genome. No obvious morphological or developmental difference was observed between the transgenic and wild-type (WT) plants. Drought and salt tolerance and gene expression of seedlings of several transgenic lines and WT plants (control) were studied. The results showed that the rhizogenesis rate and the average root-length of transgenic lines were significantly higher than WT plants after mannitol and NaCl treatment under the same growth conditions. Northern blot analysis indicated that the higher the PLDα expression in the transgenic plants, the more tolerant the transgenic plants are to drought and salt treatment. Meanwhile, another group of these transgenic lines and WT plants (control) were treated with PEG6000 and NaCI separately. The contents of chlorophylls and the activities of some antioxidant enzymes (superoxide dismutase, guaiacol peroxidase and catalase) as well as malondialdehyde and relative electrical conductivity were analyzed. Altogether, our results demonstrated that overexpression of the PLDα gene can enhance the drought and salt tolerance in transgenic P. tomentosa plants.

  4. Micropropagation, genetic engineering, and molecular biology of Populus

    Science.gov (United States)

    N. B. Klopfenstein; Y. W. Chun; M. -S. Kim; M. A. Ahuja; M. C. Dillon; R. C. Carman; L. G. Eskew

    1997-01-01

    Thirty-four Populus biotechnology chapters, written by 85 authors, are comprised in 5 sections: 1) in vitro culture (micropropagation, somatic embryogenesis, protoplasts, somaclonal variation, and germplasm preservation); 2) transformation and foreign gene expression; 3) molecular biology (molecular/genetic characterization); 4) biotic and abiotic resistance (disease,...

  5. A new diterpenoid from the stem bark of Populus davidiana

    Institute of Scientific and Technical Information of China (English)

    Xin Feng Zhang; Xiang Li; Byung Sun Min; Ki Hwan Bae

    2008-01-01

    A new diterpenoid, named populusol A (1), was isolated from the methanolic extraction of the stem bark of Populus davidiana. The structure was elucidated on the basis of extensive 1D and 2D NMR as well as HRFAB-MS spectroscopic analysis.

  6. Trade-offs between xylem hydraulic properties, wood anatomy and yield in Populus.

    Science.gov (United States)

    Hajek, Peter; Leuschner, Christoph; Hertel, Dietrich; Delzon, Sylvain; Schuldt, Bernhard

    2014-07-01

    Trees face the dilemma that achieving high plant productivity is accompanied by a risk of drought-induced hydraulic failure due to a trade-off in the trees' vascular system between hydraulic efficiency and safety. By investigating the xylem anatomy of branches and coarse roots, and measuring branch axial hydraulic conductivity and vulnerability to cavitation in 4-year-old field-grown aspen plants of five demes (Populus tremula L. and Populus tremuloides Michx.) differing in growth rate, we tested the hypotheses that (i) demes differ in wood anatomical and hydraulic properties, (ii) hydraulic efficiency and safety are related to xylem anatomical traits, and (iii) aboveground productivity and hydraulic efficiency are negatively correlated to cavitation resistance. Significant deme differences existed in seven of the nine investigated branch-related anatomical and hydraulic traits but only in one of the four coarse-root-related anatomical traits; this likely is a consequence of high intra-plant variation in root morphology and the occurrence of a few 'high-conductivity roots'. Growth rate was positively related to branch hydraulic efficiency (xylem-specific conductivity) but not to cavitation resistance; this indicates that no marked trade-off exists between cavitation resistance and growth. Both branch hydraulic safety and hydraulic efficiency significantly depended on vessel size and were related to the genetic distance between the demes, while the xylem pressure causing 88% loss of hydraulic conductivity (P88 value) was more closely related to hydraulic efficiency than the commonly used P50 value. Deme-specific variation in the pit membrane structure may explain why vessel size was not directly linked to growth rate. We conclude that branch hydraulic efficiency is an important growth-influencing trait in aspen, while the assumed trade-off between productivity and hydraulic safety is weak.

  7. Conservation status of white poplar (Populus alba L. and black poplar (Populus nigra L. in the territory of Great War Island

    Directory of Open Access Journals (Sweden)

    Šijačić-Nikolić Mirjana

    2014-01-01

    Full Text Available T he paper describes t he conservation status of white poplar (Populus alba L. and black poplar (Populus nigra L. in the territory of Great War Island. The activities of in situ and ex situ gene pool conservation have been defined in order to preserve and expand the populations of the above species, as carriers of complex wetland forest ecosystems.

  8. A genomics investigation of partitioning into and among flavonoid-derived condensed tannins for carbon sequestration in Populus

    Energy Technology Data Exchange (ETDEWEB)

    Harding, Scott, A; Tsai, Chung-jui; Lindroth, Richard, L

    2013-03-24

    The project set out to use comparative (genotype and treatment) and transgenic approaches to investigate the determinants of condensed tannin (CT) accrual and chemical variability in Populus. CT type and amount are thought to effect the decomposition of plant detritus in the soil, and thereby the sequestering of carbon in the soil. The stated objectives were: 1. Genome-wide transcriptome profiling (microarrays) to analyze structural gene, transcription factor and metabolite control of CT partitioning; 2. Transcriptomic (microarray) and chemical analysis of ontogenetic effects on CT and PG partitioning; and 3. Transgenic manipulation of flavonoid biosynthetic pathway genes to modify the control of CT composition. Objective 1: A number of approaches for perturbing CT content and chemistry were tested in Objective 1, and those included nitrogen deficit, leaf wounding, drought, and salicylic acid spraying. Drought had little effect on CTs in the genotypes we used. Plants exhibited unpredictability in their response to salicylic acid spraying, leading us to abandon its use. Reduced plant nitrogen status and leaf wounding caused reproducible and magnitudinally striking increases in leaf CT content. Microarray submissions to NCBI from those experiments are the following: GSE ID 14515: Comparative transcriptomics analysis of Populus leaves under nitrogen limitation: clone 1979. Public on Jan 04, 2010; Contributor(s) Harding SA, Tsai C GSE ID 14893: Comparative transcriptomics analysis of Populus leaves under nitrogen limitation: clone 3200. Public on Feb 19, 2009; Contributor(s) Harding SA, Tsai C GSE ID 16783 Wound-induced gene expression changes in Populus: 1 week; clone RM5. Status Public on Dec 01, 2009; Contributor(s) Harding SA, Tsai C GSE ID 16785 Wound-induced gene expression changes in Populus: 90 hours; clone RM5 Status Public on Dec 01, 2009; Contributor(s) Harding SA, Tsai C Although CT amount changed in response to treatments, CT composition was essentially

  9. Photosynthetic Characteristics of Populus deltoides Seedlings Inoculated Ectomycorrhizal Fungi and Plant Grouth Promoting Rhizobacteria under Salt Stress%盐胁迫下外生菌根真菌与根际有益细菌互作对杨树光合特性的影响

    Institute of Scientific and Technical Information of China (English)

    范克胜; 吴小芹; 任嘉红; 叶建仁

    2011-01-01

    以美洲黑杨幼苗为对象,利用盆栽试验,在100mmol/L NaCl胁迫条件下研究单接种和双接种外生菌根真菌红绒盖牛肝菌(Xerocamus chrysenteron,简称Xc)、溶磷细菌恶臭假单胞菌(Pseudomonas putida,简称JW-SX1)和菌根辅助细菌蜡状芽孢杆菌(Bacillus cereus,简称HB59)对杨树幼苗的气体交换参数、叶绿素荧光和光响应曲线参数的影响.结果表明:盐胁迫下,接种Xc、JW-SX1及HB59的杨树幼苗净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)显著增强,且均显著高于对照,而单接JW-SX1和双接Xc+JW-SX1处理的胞间CO2浓度(Ci)低于对照,但与对照相比差异不显著;各接种处理显著增强了杨树的最大光化学效率(Fv/Fm),但处理之间差异不显著性;不同接种处理杨树的实际光化学效率(φPSⅡ)与对照(CK)差异不明显,其中接种HB59和Xc+JW-SX1处理分别高于对照14.36%和19.33%;同时接种处理还明显提高了宿主的最大光合速率(Pmax)、光饱和点(LSP)、表观有效利用效率(YAQ),降低了光补偿点(LCP)和暗呼吸速率(RD),且双接种菌根真菌Xc和JW-SX1处理效果更为明显.研究发现,外生菌根真菌、溶磷细菌和菌根辅助细菌可通过改善叶片叶绿素荧光和光合参数、光响应参数来减轻盐胁迫对宿主造成的伤害,从而提高杨树的耐盐性能力.%Populus deltoides seedlings inoculated with ectomycorrhizal Fungi (EMF) Xerocamus chrysenteron Xc, phosphate-solubilizing bacteria (PSB) Pseudomonas putida JW-SX1, mycorrhiza helper bacteria (MHB) Bacillus cereus HB59 to investigate the negative effects of salt stress on photosynthesis, chlorophyll fluorescence, photosynthesis to light intensity of seedling leaves.The results showed that the photosynthetic rate (Pn) ,the stomatal conductance (Gs) and transpiration rate (Tr) of P.deltoides seedlings inoculated with X.chrysenteron, P.putida and B.cereus were higher than those of the no-inoculation under salt stress and the

  10. Impact du stress hydrique sur le fonctionnement hydraulique foliaire du peuplier Populus tremula x alba

    OpenAIRE

    Daaboul, Philippe

    2015-01-01

    Afin d’aborder l’impact du stress hydrique sur le fonctionnement hydraulique foliaire, des plants de Populus tremula x alba ont été soumis à un stress hydrique modéré ou sévère pendant une semaine par ajout de PEG dans la solution nutritive. La mesure de paramètres écophysiologiques et moléculaires tissus spécifiques a permis de dégager plusieurs tendances sur la caractérisation de l’influence du stress. Les deux types de stress n’ont que peu d’impact sur la croissance et la capacité de synth...

  11. [Cloning and structure analysis of zinc finger protein gene in Populus euphratica Oliv].

    Science.gov (United States)

    Wang, Jun-Ying; Yin, Wei-Lun; Xia, Xin-Li

    2005-03-01

    Zinc finger proteins belong to a family of nuclear transcription factors which function is to regulate gene expression in both prokaryotic and eukaryotic cells. A pair of primers was designed after analyzing the conservation of salt-tolerant zinc protein Alfin-1 in such diverse plants as alfalfa and Arabidopsis. The zinc finger protein gene is isolated from total RNA with RT-PCR in aquaculture leaves of Populus euphratica . Its full cDNA length is 924bp. Analysis of its amino acid sequence showed it has a typical Cys(2)/His(2) zinc finger structure and a G-rich promoter binding site GTGGGG, starting from position 556. Since transcrptional factors which have the same function show conservation in structure and amino acid sequence of DNA binding region, the structure analysis in this paper indicates the cloned zinc finger protein gene may have functional correlation to Alfin-1.

  12. Recovery of Populus tremuloides seedlings following severe drought causing total leaf mortality and extreme stem embolism.

    Science.gov (United States)

    Lu, Yanyuan; Equiza, Maria Alejandra; Deng, Xiping; Tyree, Melvin T

    2010-11-01

    In contrast with other native Populus species in North America, Populus tremuloides (aspen) can successfully establish itself in drought-prone areas, yet no comprehensive analysis has been performed on the ability of seedlings to withstand and recover from a severe drought resulting in complete leaf mortality. Here, we subjected 4-month-old aspen seedlings grown in two contrasting soil media to a progressive drought until total leaf mortality, followed by a rewatering cycle. Stomatal conductance (g(s) ), photosynthesis and transpiration followed a sigmoid decline with declining fraction of extractable soil water values. Cessation of leaf expansion occurred close to the end of the linear-decrease phase, when g(s) was reduced by 95%. Leaf mortality started after g(s) reached the lowest values, which corresponded to a stem-xylem pressure potential (Ψ(xp)) of -2.0 MPa and a percent loss of stem hydraulic conductivity (PLC) of 50%. In plants with 50% leaf mortality, PLC values remained around 50%. Complete leaf mortality occurred at an average stem PLC of 90%, but all seedlings were able to resprout after 6-10 days of being rewatered. Plants decapitated at soil level before rewatering developed root suckers, while those left with a 4-cm stump or with their stems intact resprouted exclusively from axillary buds. Resprouting was accompanied by recovery of stem hydraulic conductivity, with PLC values around 30%. The percentage of resprouted buds was negatively correlated with the stem %PLC. Thus, the recovery of stem hydraulic conductivity appears as an important factor in the resprouting capacity of aspen seedlings following a severe drought. Copyright © Physiologia Plantarum 2010.

  13. Multiple factors affect pest and pathogen damage on 31 Populus clones in South Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Coyle, David R.; Coleman, Mark D. [USDA Forest Service, Southern Research Station, P.O. Box 700, New Ellenton, SC 29809 (United States); Durant, Jaclin A.; Newman, Lee A. [Arnold School of Public Health, Department of Environmental Health Sciences, University of South Carolina, 800 Sumter St., Columbia, SC 29208 (United States)

    2006-08-15

    Populus species and hybrids have many practical applications, but there is a paucity of data regarding selections that perform well in the southeastern US. We compared pest susceptibility of 31 Populus clones over 3 years in South Carolina, USA. Cuttings were planted in spring 2001 on two study sites. Clones planted in the bottomland site received granular fertilizer yearly and irrigation the first two years only, while those on the sandy, upland site received irrigation and fertilization throughout each growing season. Foliar damage by the cottonwood leaf beetle (Chrysomela scripta), cottonwood leafcurl mite (Tetra lobulifera), and poplar leaf rust (Melampsora medusae) was visually monitored several times each growing season. Damage ratings differed significantly among clones, and clonal rankings changed from year to year. Irrigation increased C. scripta and M. medusae damage, but had no effect on T. lobulifera damage. Certain clones received greater pest damage at a particular study site. Temporal damage patterns were evident among individual clones and on each site. At the upland site, OP367 and 7300502 were highly resistant to all three pests; I45/51 was highly resistant to C. scripta and M. medusae; NM6 and 15-29 were highly resistant to M. medusae; and 7302801 was highly resistant to T. lobulifera and M. medusae. At the bottomland site, NM6, Eridano, I45/51, and 7302801 were highly resistant to all three pests; clone 7300502 was highly resistant to M. medusae only. Based on this preliminary 3-year study of pest damage levels, we would recommend clones NM6, Eridano, I45/51, OP367, 15-29, 7302801, 7300502, and Kentucky 8 for use in this region. (author)

  14. Distinct microbial communities within the endosphere and rhizosphere of Populus deltoides roots across contrasting soil types.

    Science.gov (United States)

    Gottel, Neil R; Castro, Hector F; Kerley, Marilyn; Yang, Zamin; Pelletier, Dale A; Podar, Mircea; Karpinets, Tatiana; Uberbacher, Ed; Tuskan, Gerald A; Vilgalys, Rytas; Doktycz, Mitchel J; Schadt, Christopher W

    2011-09-01

    The root-rhizosphere interface of Populus is the nexus of a variety of associations between bacteria, fungi, and the host plant and an ideal model for studying interactions between plants and microorganisms. However, such studies have generally been confined to greenhouse and plantation systems. Here we analyze microbial communities from the root endophytic and rhizospheric habitats of Populus deltoides in mature natural trees from both upland and bottomland sites in central Tennessee. Community profiling utilized 454 pyrosequencing with separate primers targeting the V4 region for bacterial 16S rRNA and the D1/D2 region for fungal 28S rRNA genes. Rhizosphere bacteria were dominated by Acidobacteria (31%) and Alphaproteobacteria (30%), whereas most endophytes were from the Gammaproteobacteria (54%) as well as Alphaproteobacteria (23%). A single Pseudomonas-like operational taxonomic unit (OTU) accounted for 34% of endophytic bacterial sequences. Endophytic bacterial richness was also highly variable and 10-fold lower than in rhizosphere samples originating from the same roots. Fungal rhizosphere and endophyte samples had approximately equal amounts of the Pezizomycotina (40%), while the Agaricomycotina were more abundant in the rhizosphere (34%) than endosphere (17%). Both fungal and bacterial rhizosphere samples were highly clustered compared to the more variable endophyte samples in a UniFrac principal coordinates analysis, regardless of upland or bottomland site origin. Hierarchical clustering of OTU relative abundance patterns also showed that the most abundant bacterial and fungal OTUs tended to be dominant in either the endophyte or rhizosphere samples but not both. Together, these findings demonstrate that root endophytic communities are distinct assemblages rather than opportunistic subsets of the rhizosphere.

  15. Distinct Microbial Communities within the Endosphere and Rhizosphere of Populus deltoides Roots across Contrasting Soil Types.

    Energy Technology Data Exchange (ETDEWEB)

    Gottel, Neil R [ORNL; Castro Gonzalez, Hector F [ORNL; Kerley, Marilyn K [ORNL; Yang, Zamin [ORNL; Pelletier, Dale A [ORNL; Podar, Mircea [ORNL; Karpinets, Tatiana V [ORNL; Uberbacher, Edward C [ORNL; Tuskan, Gerald A [ORNL; Vilgalys, Rytas [Duke University; Doktycz, Mitchel John [ORNL; Schadt, Christopher Warren [ORNL

    2011-01-01

    The root-rhizosphere interface of Populus is the nexus of a variety of associations between bacteria, fungi, and the host plant and an ideal model for studying interactions between plants and microorganisms. However, such studies have generally been confined to greenhouse and plantation systems. Here we analyze microbial communities from the root endophytic and rhizospheric habitats of Populus deltoides in mature natural trees from both upland and bottomland sites in central Tennessee. Community profiling utilized 454 pyrosequencing with separate primers targeting the V4 region for bacterial 16S rRNA and the D1/D2 region for fungal 28S rRNA genes. Rhizosphere bacteria were dominated by Acidobacteria (31%) and Alphaproteobacteria (30%), whereas most endophytes were from the Gammaproteobacteria (54%) as well as Alphaproteobacteria (23%). A single Pseudomonas-like operational taxonomic unit (OTU) accounted for 34% of endophytic bacterial sequences. Endophytic bacterial richness was also highly variable and 10-fold lower than in rhizosphere samples originating from the same roots. Fungal rhizosphere and endophyte samples had approximately equal amounts of the Pezizomycotina (40%), while the Agaricomycotina were more abundant in the rhizosphere (34%) than endosphere (17%). Both fungal and bacterial rhizosphere samples were highly clustered compared to the more variable endophyte samples in a UniFrac principal coordinates analysis, regardless of upland or bottomland site origin. Hierarchical clustering of OTU relative abundance patterns also showed that the most abundant bacterial and fungal OTUs tended to be dominant in either the endophyte or rhizosphere samples but not both. Together, these findings demonstrate that root endophytic communities are distinct assemblages rather than opportunistic subsets of the rhizosphere.

  16. Genetic variation in functional traits influences arthropod community composition in aspen (Populus tremula L..

    Directory of Open Access Journals (Sweden)

    Kathryn M Robinson

    Full Text Available We conducted a study of natural variation in functional leaf traits and herbivory in 116 clones of European aspen, Populus tremula L., the Swedish Aspen (SwAsp collection, originating from ten degrees of latitude across Sweden and grown in a common garden. In surveys of phytophagous arthropods over two years, we found the aspen canopy supports nearly 100 morphospecies. We identified significant broad-sense heritability of plant functional traits, basic plant defence chemistry, and arthropod community traits. The majority of arthropods were specialists, those coevolved with P. tremula to tolerate and even utilize leaf defence compounds. Arthropod abundance and richness were more closely related to plant growth rates than general chemical defences and relationships were identified between the arthropod community and stem growth, leaf and petiole morphology, anthocyanins, and condensed tannins. Heritable genetic variation in plant traits in young aspen was found to structure arthropod community; however no single trait drives the preferences of arthropod folivores among young aspen genotypes. The influence of natural variation in plant traits on the arthropod community indicates the importance of maintaining genetic variation in wild trees as keystone species for biodiversity. It further suggests that aspen can be a resource for the study of mechanisms of natural resistance to herbivores.

  17. Genetic variation in functional traits influences arthropod community composition in aspen (Populus tremula L.).

    Science.gov (United States)

    Robinson, Kathryn M; Ingvarsson, Pär K; Jansson, Stefan; Albrectsen, Benedicte R

    2012-01-01

    We conducted a study of natural variation in functional leaf traits and herbivory in 116 clones of European aspen, Populus tremula L., the Swedish Aspen (SwAsp) collection, originating from ten degrees of latitude across Sweden and grown in a common garden. In surveys of phytophagous arthropods over two years, we found the aspen canopy supports nearly 100 morphospecies. We identified significant broad-sense heritability of plant functional traits, basic plant defence chemistry, and arthropod community traits. The majority of arthropods were specialists, those coevolved with P. tremula to tolerate and even utilize leaf defence compounds. Arthropod abundance and richness were more closely related to plant growth rates than general chemical defences and relationships were identified between the arthropod community and stem growth, leaf and petiole morphology, anthocyanins, and condensed tannins. Heritable genetic variation in plant traits in young aspen was found to structure arthropod community; however no single trait drives the preferences of arthropod folivores among young aspen genotypes. The influence of natural variation in plant traits on the arthropod community indicates the importance of maintaining genetic variation in wild trees as keystone species for biodiversity. It further suggests that aspen can be a resource for the study of mechanisms of natural resistance to herbivores.

  18. Spatial distribution characteristics of fine roots of Populus euphratica in a desert riparian forest

    Institute of Scientific and Technical Information of China (English)

    Jianhua SI; Qi FENG; Jianlin LI; Jian ZHAO

    2008-01-01

    The soil-plant system is a very important sub-system of the soil-plant-atmosphere continuum (SPAC). The water uptake by plant roots is an important subject in the research on water transport in this SPAC and is also the most active study direction in the fields of ecology, hydrology and environment. The study of the spatial dis-tribution pattern of fine roots of plants is the basis of constructing a water absorption model of plant roots. Our study on the spatial distribution pattern of fine roots of Populus euphratica in a desert riparian forest shows that the density distribution of its root lengths can be expressed horizontally as a parabola. The fine roots are concen-trated within the range of 0-350 cm from the tree trunk and their amount accounts for 91.9% of the total root mass within the space of 0-500 cm. In the vertical dir-ection, the density distribution of the fine root lengths shows a negative exponential relation with soil depth. The fine roots are concentrated in the 0-80 cm soil layer, accounting for 96.8% of the total root mass in the 0-140 cm soil layer.

  19. Metabolic functions of Pseudomonas fluorescens strains from Populus deltoides depend on rhizosphere or endosphere isolation compartment

    Directory of Open Access Journals (Sweden)

    Collin M Timm

    2015-10-01

    Full Text Available The bacterial microbiota of plants is diverse, with 1,000s of operational taxonomic units (OTUs associated with any individual plant. In this work we investigate the differences between 19 sequenced Pseudomonas fluorescens strains, isolated from Populus deltoides rhizosphere and endosphere and which represent a single OTU, using phenotypic analysis, comparative genomics, and metabolic models. While no traits were exclusive to either endosphere or rhizosphere P. fluorescens isolates, multiple pathways relevant for plant-bacterial interactions are enriched in endosphere isolate genomes. Further, growth phenotypes such as phosphate solubilization, protease activity, denitrification and root growth promotion are biased towards endosphere isolates. Endosphere isolates have significantly more metabolic pathways for plant signaling compounds and an increased metabolic range that includes utilization of energy rich nucleotides and sugars, consistent with endosphere colonization. Rhizosphere P. fluorescens have fewer pathways representative of plant-bacterial interactions but show metabolic bias towards chemical substrates often found in root exudates. This work reveals the diverse functions that may contribute to colonization of the endosphere by bacteria and are enriched among closely related isolates.

  20. Impact of Drying Methods on Wettability of Populus tomentosa

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Plantation poplar is one of the most important resources for wood industry, its utilization field is vast. The wettability of Populus tomentosa with different drying methods was judged by measurement of contact angle using distilled water in this paper. The results showed that the specimens from conventional drying have the biggest contact angle, and the air dried have the smallest contact angle, air dried lumbers have a better wettability than the kiln dried. The changes of contact angle in a period of tim...

  1. Construction of a bidirectional promoter and its transient expression in Populus tomentosa

    Institute of Scientific and Technical Information of China (English)

    Chunxiao ZHANG; Ying GAI; Yanyan ZHU; Xuemei CHEN; Xiangning JIANG

    2008-01-01

    Simultaneous introduction of multiple genes into plants is a critical step in plant genetic engineering to manipulate multiple functional genes in metabolic engineering and trait stacking. It is important to construct a bidirectional promoter for transforming two or more genes into plants simultaneously. The widely used unidirectional CaMV35S promoter has been mod-ified to a bidirectional promoter in this work by fusing a CaMV35S minimal promoter (Pmini) at its end in opposite orientation to the original promoter. To test its bi-directional transcriptional activities, two widely used histochemically visible reporter genes, gusA (β-glucuronidase) from Escherichia coli and gfp (Green Fluorescent Protein) from Aequorea victoria, were fused to the terminus of the bidirectional promoter in different orientations ending with NOS terminator sequences. The transient expression of the gusA and gfp genes were detected by histochemical staining for GUS and by fluorescence microscopy for GFP. The direction of transient expression of GUS and GFP in Agro-bacterium mediated 3-4 days transformed leaf discs of Populus tomentosa, indicating that the promoter did have bidirectional transcriptional activities simultaneously in cells and tissues. It was discussed that this bidirectional promoter could possibly be applied in woody plant engineering.

  2. Early events in Populus hybrid and Fagus sylvatica leaves exposed to ozone.

    Science.gov (United States)

    Desotgiu, R; Bussotti, F; Faoro, F; Iriti, M; Agati, G; Marzuoli, R; Gerosa, G; Tani, C

    2010-04-01

    This paper aims to investigate early responses to ozone in leaves of Fagus sylvatica (beech) and Populus maximowiczii x Populus berolinensis (poplar). The experimental setup consisted of four open-air (OA) plots, four charcoal-filtered (CF) open-top chambers (OTCs), and four nonfiltered (NF) OTCs. Qualitative and quantitative analyses were carried out on nonsymptomatic (CF) and symptomatic (NF and OA) leaves of both species. Qualitative analyses were performed applying microscopic techniques: Evans blue staining for detection of cell viability, CeCl3 staining of transmission electron microscope (TEM) samples to detect the accumulation of H2O2, and multispectral fluorescence microimaging and microspectrofluorometry to investigate the accumulation of fluorescent phenolic compounds in the walls of the damaged cells. Quantitative analyses consisted of the analysis of the chlorophyll a fluorescence transients (fast kinetics). The early responses to ozone were demonstrated by the Evans blue and CeCl3 staining techniques that provided evidence of plant responses in both species 1 month before foliar symptoms became visible. The fluorescence transients analysis, too, demonstrated the breakdown of the oxygen evolving system and the inactivation of the end receptors of electrons at a very early stage, both in poplar and in beech. The accumulation of phenolic compounds in the cell walls, on the other hand, was a species-specific response detected in poplar, but not in beech. Evans blue and CeCl3 staining, as well as the multispectral fluorescence microimaging and microspectrofluorometry, can be used to support the field diagnosis of ozone injury, whereas the fast kinetics of chlorophyll fluorescence provides evidence of early physiological responses.

  3. Early Events in Populus Hybrid and Fagus sylvatica Leaves Exposed to Ozone

    Directory of Open Access Journals (Sweden)

    R. Desotgiu

    2010-01-01

    Full Text Available This paper aims to investigate early responses to ozone in leaves of Fagus sylvatica (beech and Populus maximowiczii x Populus berolinensis (poplar. The experimental setup consisted of four open-air (OA plots, four charcoal-filtered (CF open-top chambers (OTCs, and four nonfiltered (NF OTCs. Qualitative and quantitative analyses were carried out on nonsymptomatic (CF and symptomatic (NF and OA leaves of both species. Qualitative analyses were performed applying microscopic techniques: Evans blue staining for detection of cell viability, CeCl3 staining of transmission electron microscope (TEM samples to detect the accumulation of H2O2, and multispectral fluorescence microimaging and microspectrofluorometry to investigate the accumulation of fluorescent phenolic compounds in the walls of the damaged cells. Quantitative analyses consisted of the analysis of the chlorophyll a fluorescence transients (fast kinetics. The early responses to ozone were demonstrated by the Evans blue and CeCl3 staining techniques that provided evidence of plant responses in both species 1 month before foliar symptoms became visible. The fluorescence transients analysis, too, demonstrated the breakdown of the oxygen evolving system and the inactivation of the end receptors of electrons at a very early stage, both in poplar and in beech. The accumulation of phenolic compounds in the cell walls, on the other hand, was a species-specific response detected in poplar, but not in beech. Evans blue and CeCl3 staining, as well as the multispectral fluorescence microimaging and microspectrofluorometry, can be used to support the field diagnosis of ozone injury, whereas the fast kinetics of chlorophyll fluorescence provides evidence of early physiological responses.

  4. A systems biology, whole-genome association analysis of the molecular regulation of biomass growth and composition in Populus deltoides

    Energy Technology Data Exchange (ETDEWEB)

    Kirst, Matias [Univ. of Florida, Gainesville, FL (United States)

    2015-04-15

    Poplars trees are well suited for biofuel production due to their fast growing habit, favorable wood composition and adaptation to a broad range of environments. The availability of a reference genome sequence, ease of vegetative propagation and availability of transformation methods also make poplar an ideal model for the study of wood formation and biomass growth in woody, perennial plants. The objective of this project was to conduct a genome-wide association genetics study to identify genes that regulate bioenergy traits in Populus deltoides (eastern cottonwood). Populus deltoides is a genetically diverse keystone forest species in North America and an important short rotation woody crop for the bioenergy industry. We searched for associations between eight growth and wood composition traits and common and low-frequency single-nucleotide polymorphisms (SNPs) detected by targeted resequencing of 18,153 genes in a population of 391 unrelated individuals. To increase power to detect associations with low-frequency variants, multiple-marker association tests were used in combination with single-marker association tests. Significant associations were discovered for all phenotypes and are indicative that low-frequency polymorphisms contribute to phenotypic variance of several bioenergy traits. These polymorphism are critical tools for the development of specialized plant feedstocks for bioenergy.

  5. A systems biology, whole-genome association analysis of the molecular regulation of biomass growth and composition in Populus deltoides

    Energy Technology Data Exchange (ETDEWEB)

    Kirst, Matias [Univ. of Florida, Gainesville, FL (United States)

    2014-04-14

    Poplars trees are well suited for biofuel production due to their fast growing habit, favorable wood composition and adaptation to a broad range of environments. The availability of a reference genome sequence, ease of vegetative propagation and availability of transformation methods also make poplar an ideal model for the study of wood formation and biomass growth in woody, perennial plants. The objective of this project was to conduct a genome-wide association genetics study to identify genes that regulate bioenergy traits in Populus deltoides (eastern cottonwood). Populus deltoides is a genetically diverse keystone forest species in North America and an important short rotation woody crop for the bioenergy industry. We searched for associations between eight growth and wood composition traits and common and low-frequency single-nucleotide polymorphisms (SNPs) detected by targeted resequencing of 18,153 genes in a population of 391 unrelated individuals. To increase power to detect associations with low-frequency variants, multiple-marker association tests were used in combination with single-marker association tests. Significant associations were discovered for all phenotypes and are indicative that low-frequency polymorphisms contribute to phenotypic variance of several bioenergy traits. These polymorphism are critical tools for the development of specialized plant feedstocks for bioenergy.

  6. The Populus homeobox gene ARBORKNOX1 reveals overlapping mechanisms regulating the shoot apical meristem and the vascular cambium.

    Science.gov (United States)

    Groover, Andrew T; Mansfield, Shawn D; DiFazio, Stephen P; Dupper, Gayle; Fontana, Joseph R; Millar, Ryan; Wang, Yvonne

    2006-08-01

    Secondary growth is supported by a dividing population of meristematic cells within the vascular cambium whose daughter cells are recruited to differentiate within secondary phloem and xylem tissues. We cloned a Populus Class 1 KNOX homeobox gene, ARBORKNOX1 (ARK1), which is orthologous to Arabidopsis SHOOT MERISTEMLESS (STM). ARK1 is expressed in the shoot apical meristem (SAM) and the vascular cambium, and is down-regulated in the terminally differentiated cells of leaves and secondary vascular tissues that are derived from these meristems. Transformation of Populus with either ARK1 or STM over-expression constructs results in similar morphological phenotypes characterized by inhibition of the differentiation of leaves, internode elongation, and secondary vascular cell types in stems. Microarray analysis showed that 41% of genes up-regulated in the stems of ARK1 over-expressing plants encode proteins involved in extracellular matrix synthesis or modification, including proteins involved in cell identity and signaling, cell adhesion, or cell differentiation. These gene expression differences are reflected in alterations of cell wall biochemistry and lignin composition in ARK1 over-expressing plants. Our results suggest that ARK1 has a complex mode of action that may include regulating cell fates through modification of the extracellular matrix. Our findings support the hypothesis that the SAM and vascular cambium are regulated by overlapping genetic programs.

  7. 拟南芥、水稻和毛果杨中CesA基因的进化和表达分析%Phylogenetic and expression analysis of CesA genes in Arabidopsis thaliana, Oryza sativa and Populus trichocarpa

    Institute of Scientific and Technical Information of China (English)

    朱煜; 谭梦月; 邹爱兰; 张文举; 戚金亮; 杨永华

    2013-01-01

    纤维素是植物细胞壁的主要成分,纤维素合成酶是纤维素合成过程中重要的酶类.利用拟南芥(草本植物)、水稻(禾本科作物)、毛果杨(木本植物)3种已知全基因组序列的模式植物,对纤维素合成酶基因(CesA)家族的成员进行系统分析,了解CesA基因超基因家族的进化关系.研究结果表明,CesA基因在物种分化之前就已经存在,并且在各个物种内部出现了基因扩张,不同物种扩张程度不同,整个基因家族呈负选择压力.为进一步探讨该家族基因的表达调控模式,以水稻为例对该基因家族的启动子元件进行了分析,发现OsCesA基因可能受到多种胁迫和激素信号的调控;而RT-PCR结果表明ABA可以显著下调该类基因的表达.

  8. Management of aspen plant communities on the National Elk Refuge, Wyoming

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — There are 1,860 acres (753 ha) of aspen (Populus tremuloides) plant communities on the National Elk Refuge (NER). Aspen is an important tree species on the Refuge,...

  9. Analysis of the Correlation between the Geographical Distribution of Populus euphratica Oliv. and the Climatic Environment

    Institute of Scientific and Technical Information of China (English)

    Yinke YANG; Zhenglong YAN

    2012-01-01

    [Objective] This research was to study the correlation regional climatic characteristics and changing geographic distribution of Populus euphratica Oily. (Sali- caceae), as well as the adaption of Populus euphratica Oliv. to the climatic environ- ment. [Method] The climatic characteristics, water source, groundwater and soil type in the distribution regions of Populus euphratica Oliv. and the effect of long-term hu- man activities were comprehensively analyzed based an overview of Populus eu- phratica Oliv. and its distribution. [Result] Specific regional climatic characteristics and long term human activities are the principle determinants for the growth of Populus euphratica Oliv. The change of leaf shape is a distinct feature of Populus euphratica Oliv. in adapting to the climatic environment. Populus euphratica Oliv. withstands various environmental stresses by means of in vivo synthesis, transport and conver- sion of secondary phenolic metabolites. Effective protection and rehabilitation mea- sures, and ecological water transport have obvious effect on the restoration and re- construction of damaged ecological environment of Populus euphratica oasis. [Con- clusion] This study is of great significance for the restoration of ecological environ- ment in the arid inland regions, north-west China.

  10. Cottonwood Leaf Beetle (Coleoptera: Chrysomelidae) Larval Performance on Eight Populus Clones

    Science.gov (United States)

    David R. Coyle; Joel D. McMillin; Richard B. Hall; Elwood R. Hart

    2001-01-01

    Abstract: The cottonwood leaf beetle, Chrysomela scripta F., is the most serious defoliator of young plantation-grown Populus in the eastern United States, yet there is a paucity of data on larval feeding performance across Populus clones used in tree breeding. Field experiments were conducted in 1998 and 1999...

  11. Genic diversity of natural populations of a clone-forming tree Populus tremuloides

    Energy Technology Data Exchange (ETDEWEB)

    Cheliak, W.M.; Dancik, B.P.

    1982-01-01

    Effects of asexual reproduction as a primary reproductive strategy on population structure and levels of variability were investigated electrophoretically in natural populations of a woody plant species, trembling aspen (Populus tremuloides Michx.). from Alberta. As expected, levels of genic diversity, 42%, and proportion of polymorphic loci, 92%, averaged over all clones are considerably greater than those reported for comparable samples of sexually reproducing plant and animal species. These measures of genic variability of a primary asexual plant species are similar to those reported for asexual species of insects, fish and bacteria. In addition, each of 222 clones was electrophoretically unique. Since neutral theory would predict each individual clone to be heterozygous for a unique mutation at each gene locus at equilibrium, these results can be interpreted in a number of ways: (i) insufficient time to reach equilibrium, (ii) inability of electrophoresis to detect all variation at a locus, (iii) periodic establishment of sexually derived propagules in the population, and (iv) selection for similar genotypes at each location or against mutations at particular gene loci. Re-invasion of Pleistocene-glaciated areas by trembling aspen was likely by sexual means, with subsequent reproduction being primarily asexual. (Refs. 26)

  12. Improvement in salt tolerance of Populus tomentosa from transformation by a mtl-D gene

    Institute of Scientific and Technical Information of China (English)

    Li Min; Wang Hua-fang; Yin Wei-lun; He Si-jie; Chen Shou-yi

    2006-01-01

    Transgenic lines were achieved by transforming the E. coli 1-phosphate mannitol dehydrogenase gene (mtl-D) into the Populus tomentosa Carr. genome. An Agrobacterium tumefaciens strain (AGL1), constructed by cloning mtl-D into the disarmed plasmid pBin438, was used to infect leaves of the clone YW2. The infected leaf discs were cultured on a medium containing 30mg·L-1 kanamycin and 500 mg·L-1 cefotaxime. Transgenic plantlets regenerated from the infected leaves, rooted on the medium containing 30 mg·L-1 kanamycin. PCR and a Southern blotting test verified that the exogenous mtl-D gene had integrated into the transformation plants of the P. tomentosa genome. The mannitol content in control plant was 69 μg·g-1 FW, and the mannitol contents of the transgenic lines T1 to T5 ranged between 103.7 and 289.5 μg·g-1 FW. Of the shoots of the control plants 20% survived; on the medium containing 0.6% NaCl, 60% and 70% of two transgenic shoots survived on a medium containing 0.8% NaCl.

  13. On the irrigation requirements of cottonwood (Populus fremontii and Populus deltoides var. wislizenii) and willow (Salix gooddingii) grown in a desert environment

    Science.gov (United States)

    Hartwell, S.; Morino, K.; Nagler, P.L.; Glenn, E.P.

    2010-01-01

    Native tree plots have been established in river irrigation districts in the western U.S. to provide habitat for threatened and endangered birds. Information is needed on the effective irrigation requirements of the target species. Cottonwood (Populus spp.) and willow (Salix gooddingii) trees were grown for seven years in an outdoor plot in a desert environment in Tucson, Arizona. Plants were allowed to achieve a nearly complete canopy cover over the first four years, then were subjected to three daily summer irrigation schedules of 6.20??mm??d-1; 8.26??mm??d-1 and 15.7??mm??d-1. The lowest irrigation rate was sufficient to maintain growth and high leaf area index for cottonwoods over three years, while willows suffered considerable die-back on this rate in years six and seven. These irrigation rates were applied April 15-September 15, but only 0.88??mm??d-1 was applied during the dormant period of the year. Expressed as a fraction of reference crop evapotranspiration (ETo), recommended annual water applications plus precipitation (and including some deep drainage) were 0.83 ETo for cottonwood and 1.01 ETo for willow. Current practices tend to over-irrigate restoration plots, and this study can provide guidelines for more efficient water use. ?? 2010 Elsevier Ltd.

  14. Glycosylation-mediated phenylpropanoid partitioning in Populus tremuloides cell cultures

    Directory of Open Access Journals (Sweden)

    Babst Benjamin A

    2009-12-01

    Full Text Available Abstract Background Phenylpropanoid-derived phenolic glycosides (PGs and condensed tannins (CTs comprise large, multi-purpose non-structural carbon sinks in Populus. A negative correlation between PG and CT concentrations has been observed in several studies. However, the molecular mechanism underlying the relationship is not known. Results Populus cell cultures produce CTs but not PGs under normal conditions. Feeding salicyl alcohol resulted in accumulation of salicins, the simplest PG, in the cells, but not higher-order PGs. Salicin accrual reflected the stimulation of a glycosylation response which altered a number of metabolic activities. We utilized this suspension cell feeding system as a model for analyzing the possible role of glycosylation in regulating the metabolic competition between PG formation, CT synthesis and growth. Cells accumulated salicins in a dose-dependent manner following salicyl alcohol feeding. Higher feeding levels led to a decrease in cellular CT concentrations (at 5 or 10 mM, and a negative effect on cell growth (at 10 mM. The competition between salicin and CT formation was reciprocal, and depended on the metabolic status of the cells. We analyzed gene expression changes between controls and cells fed with 5 mM salicyl alcohol for 48 hr, a time point when salicin accumulation was near maximum and CT synthesis was reduced, with no effect on growth. Several stress-responsive genes were up-regulated, suggestive of a general stress response in the fed cells. Salicyl alcohol feeding also induced expression of genes associated with sucrose catabolism, glycolysis and the Krebs cycle. Transcript levels of phenylalanine ammonia lyase and most of the flavonoid pathway genes were reduced, consistent with down-regulated CT synthesis. Conclusions Exogenous salicyl alcohol was readily glycosylated in Populus cell cultures, a process that altered sugar utilization and phenolic partitioning in the cells. Using this system, we

  15. A Novel Antioxidant Phenyl Disaccharide from Populus tremula Knotwood

    Directory of Open Access Journals (Sweden)

    Bjarne Holmbom

    2007-02-01

    Full Text Available The complete characterization of two compounds obtained from the acetoneextract of Populus tremula knotwood has been was achieved using LC-DAD-MS,MS/MS, IR and NMR. The new compounds were unequivocally identified as a mixtureof the ester isomers of the (E and (Z p-coumarate of 1-O-rutinose. The isomers showedthe capacity to inhibit lipid peroxidation induced by tert-butylhydroperoxide and to trapperoxyl radicals, as determined by a chemiluminescence method. These new phenyldisaccharides also showed a significant ORAC (oxygen radical absorbance capacityvalue, i.e. 11.7 μM TE (Trolox Equivalents.

  16. Genome Sequence of the Plant Growth Promoting Endophytic Bacterium Enterobacter sp. 638

    Energy Technology Data Exchange (ETDEWEB)

    Taghavi, S.; van der Lelie, D.; Hoffman, A.; Zhang, Y.-B.; Walla, M. D.; Vangronsveld, J.; Newman, L.; Monchy, S.

    2010-05-13

    Enterobacter sp. 638 is an endophytic plant growth promoting gamma-proteobacterium that was isolated from the stem of poplar (Populus trichocarpa x deltoides cv. H11-11), a potentially important biofuel feed stock plant. The Enterobacter sp. 638 genome sequence reveals the presence of a 4,518,712 bp chromosome and a 157,749 bp plasmid (pENT638-1). Genome annotation and comparative genomics allowed the identification of an extended set of genes specific to the plant niche adaptation of this bacterium. This includes genes that code for putative proteins involved in survival in the rhizosphere (to cope with oxidative stress or uptake of nutrients released by plant roots), root adhesion (pili, adhesion, hemagglutinin, cellulose biosynthesis), colonization/establishment inside the plant (chemiotaxis, flagella, cellobiose phosphorylase), plant protection against fungal and bacterial infections (siderophore production and synthesis of the antimicrobial compounds 4-hydroxybenzoate and 2-phenylethanol), and improved poplar growth and development through the production of the phytohormones indole acetic acid, acetoin, and 2,3-butanediol. Metabolite analysis confirmed by quantitative RT-PCR showed that, the production of acetoin and 2,3-butanediol is induced by the presence of sucrose in the growth medium. Interestingly, both the genetic determinants required for sucrose metabolism and the synthesis of acetoin and 2,3-butanediol are clustered on a genomic island. These findings point to a close interaction between Enterobacter sp. 638 and its poplar host, where the availability of sucrose, a major plant sugar, affects the synthesis of plant growth promoting phytohormones by the endophytic bacterium. The availability of the genome sequence, combined with metabolome and transcriptome analysis, will provide a better understanding of the synergistic interactions between poplar and its growth promoting endophyte Enterobacter sp. 638. This information can be further exploited to

  17. Mixed, short rotation culture of red alder and black cottonwood: growth, coppicing, nitrogen fixation, and allelopathy

    Energy Technology Data Exchange (ETDEWEB)

    Heilman, P.; Stettler, R.F.

    1985-01-01

    Alnus rubra seedlings were grown in a 1:1 mixture at a spacing of 1.2 x 1.2 m with 28 Populus clones (25 clones pf P. trichocarpa, 2 of P. deltoides x P. trichocarpa, and one P. deltoides x P. nigra) in a study established in W. Washington in March 1979. Trees were harvested at 4 yr old. At harvest, average heights were: pure Populus, 10.2 m; Populus in the mixed stand 11.0 m; and alder 8.4 m. Most Populus sprouted satisfactorily after harvest (6.6 shoots/plant when pure, 7.6 shoots/plant in the mixture), but alder sprouted poorly (3.6 shoots/plant). Above-ground biomass at harvest was 15.9 t/ha p.a. for the mixture and 16.7 t/ha p.a. for pure Populus, although the mixture had been more productive at 2 yr. Nitrogenase activity (nitrogen fixation as measured by acetylene reduction) of alder declines in the 4th season; competition was the most important factor influencing this decline. Soil N content had no effect on fixation. A pot study showed that ground Populus leaf and litter material inhibited the growth of red alder seedlings, although soil collected from Populus plots had no effect. Results indicated that allelopathy is probably a minor factor under field conditions, at most, and that growing mixed stands may, on balance, be beneficial. 20 references.

  18. Moderate drought did not affect the effectiveness of ethylenediurea (EDU) in protecting Populus cathayana from ambient ozone.

    Science.gov (United States)

    Xin, Yue; Yuan, Xiangyang; Shang, Bo; Manning, William J; Yang, Aizhen; Wang, Younian; Feng, Zhaozhong

    2016-11-01

    A field study was conducted to evaluate the effects of ambient ozone (O3) on an O3-sensitive poplar (Populus cathayana) by using ethylenediurea (EDU) as a chemical protectant under two soil water treatments (well-watered (WW) and moderate drought (MD, 50-60% of WW in volumetric soil water content). EDU was applied as foliar spray at 0, 300, 450, and 600ppm. Photosynthetic parameters, pigment contents, leaf nitrogen, antioxidant capacity, growth, and biomass were measured. The 8h (9:00-17:00) average ambient O3 concentration was 71.7ppb, and AOT40 was 29.2ppmh during the experimental period (9 June to 21 September), which was high enough to cause plant injury. MD had significantly negative effects on P. cathayana, as indicated by reduced photosynthesis, growth, and biomass, and higher MDA contents. On the other hand, EDU significantly increased photosynthesis rate, chlorophyll a fluorescence, Vcmax and Jmax, photosynthetic pigments, total antioxidant capacity, tree growth and biomass accumulation, and reduced lipid peroxidation, but there was no significant interaction between EDU and drought for most parameters, indicating that EDU can efficiently protect Populus cathayana against ambient O3 and the protection was not affected by soil water contents when soil water reached moderate drought level. Among all doses, EDU at 450ppm provided maximum protection. Comparison of EDU-treated and non-treated P. cathayana could be used as a biomarker system in risk assessment of the effects of ambient O3 on forest health.

  19. A Novel Moderate Constitutive Promoter Derived from Poplar (Populus tomentosa Carrière

    Directory of Open Access Journals (Sweden)

    Xin-Min An

    2013-03-01

    Full Text Available A novel sequence that functions as a promoter element for moderate constitutive expression of transgenes, designated as the PtMCP promoter, was isolated from the woody perennial Populus tomentosa. The PtMCP promoter was fused to the GUS reporter gene to characterize its expression pattern in different species. In stable Arabidopsis transformants, transcripts of the GUS reporter gene could be detected by RT-PCR in the root, stem, leaf, flower and silique. Further histochemical and fluorometric GUS activity assays demonstrated that the promoter could direct transgene expression in all tissues and organs, including roots, stems, rosette leaves, cauline leaves and flowers of seedlings and maturing plants. Its constitutive expression pattern was similar to that of the CaMV35S promoter, but the level of GUS activity was significantly lower than in CaMV35S promoter::GUS plants. We also characterized the promoter through transient expression in transgenic tobacco and observed similar expression patterns. Histochemical GUS staining and quantitative analysis detected GUS activity in all tissues and organs of tobacco, including roots, stems, leaves, flower buds and flowers, but GUS activity in PtMCP promoter::GUS plants was significantly lower than in CaMV35S promoter::GUS plants. Our results suggested that the PtMCP promoter from poplar is a constitutive promoter with moderate activity and that its function is presumably conserved in different species. Therefore, the PtMCP promoter may provide a practical choice to direct moderate level constitutive expression of transgenes and could be a valuable new tool in plant genetic engineering.

  20. Examination of correlation between histidine and nickel absorption by Morus L., Robinia pseudoacacia L. and Populus nigra L. using HPLC-MS and ICP-MS.

    Science.gov (United States)

    Ozen, Sukran Akkus; Yaman, Mehmet

    2016-08-02

    In this study, HPLC-MS and ICP-MS methods were used for the determination of histidine and nickel in Morus L., Robinia pseudoacacia L., and Populus nigra L. leaves taken from industrial areas including Gaziantep and Bursa cities. In the determination of histidine by HPLC-MS, all of the system parameters such as flow rate of mobile phase, fragmentor potential, injection volume and column temperature were optimized and found to be 0.2 mL min(-1), 70 V, 15 µL, and 20°C, respectively. Under the optimum conditions, histidine was extracted from plant sample by distilled water at 90°C for 30 min. Concentrations of histidine as mg kg(-1) were found to be between 2-9 for Morus L., 6-13 for Robinia pseudoacacia L., and 2-10 for Populus nigra L. Concentrations of nickel were in the ranges of 5-10 mg kg(-1) for Morus L., 3-10 mg kg(-1) for Robinia pseudoacacia L., and 0.6-4 mg kg(-1) for Populus nigra L. A significant linear correlation (r = 0.78) between histidine and Ni was observed for Populus nigra L., whereas insignificant linear correlation for Robinia pseudoacacia L. (r = 0.22) were seen. Limits of detection (LOD) and quantitation (LOQ) were found to be 0.025 mg Ni L(-1) and 0.075 mg Ni L(-1), respectively.

  1. Comparative physiological and proteomic analyses of poplar (Populus yunnanensis plantlets exposed to high temperature and drought.

    Directory of Open Access Journals (Sweden)

    Xiong Li

    Full Text Available Plantlets of Populus yunnanensis Dode were examined in a greenhouse for 48 h to analyze their physiological and proteomic responses to sustained heat, drought, and combined heat and drought. Compared with the application of a single stress, simultaneous treatment with both stresses damaged the plantlets more heavily. The plantlets experienced two apparent response stages under sustained heat and drought. During the first stage, malondialdehyde and reactive oxygen species (ROS contents were induced by heat, but many protective substances, including antioxidant enzymes, proline, abscisic acid (ABA, dehydrin, and small heat shock proteins (sHSPs, were also stimulated. The plants thus actively defended themselves against stress and exhibited few pathological morphological features, most likely because a new cellular homeostasis was established through the collaborative operation of physiological and proteomic responses. During the second stage, ROS homeostasis was overwhelmed by substantial ROS production and a sharp decline in antioxidant enzyme activities, while the synthesis of some protective elements, such as proline and ABA, was suppressed. As a result, photosynthetic levels in P. yunnanensis decreased sharply and buds began to die, despite continued accumulation of sHSPs and dehydrin. This study supplies important information about the effects of extreme abiotic environments on woody plants.

  2. Gibberellins regulate lateral root formation in Populus through interactions with auxin and other hormones.

    Science.gov (United States)

    Gou, Jiqing; Strauss, Steven H; Tsai, Chung Jui; Fang, Kai; Chen, Yiru; Jiang, Xiangning; Busov, Victor B

    2010-03-01

    The role of gibberellins (GAs) in regulation of lateral root development is poorly understood. We show that GA-deficient (35S:PcGA2ox1) and GA-insensitive (35S:rgl1) transgenic Populus exhibited increased lateral root proliferation and elongation under in vitro and greenhouse conditions, and these effects were reversed by exogenous GA treatment. In addition, RNA interference suppression of two poplar GA 2-oxidases predominantly expressed in roots also decreased lateral root formation. GAs negatively affected lateral root formation by inhibiting lateral root primordium initiation. A whole-genome microarray analysis of root development in GA-modified transgenic plants revealed 2069 genes with significantly altered expression. The expression of 1178 genes, including genes that promote cell proliferation, growth, and cell wall loosening, corresponded to the phenotypic severity of the root traits when transgenic events with differential phenotypic expression were compared. The array data and direct hormone measurements suggested crosstalk of GA signaling with other hormone pathways, including auxin and abscisic acid. Transgenic modification of a differentially expressed gene encoding an auxin efflux carrier suggests that GA modulation of lateral root development is at least partly imparted by polar auxin transport modification. These results suggest a mechanism for GA-regulated modulation of lateral root proliferation associated with regulation of plant allometry during the stress response.

  3. Quantitative Genetic Analysis of Biomass and Wood Chemistry of Populus under Different Nitrogen Levels

    Energy Technology Data Exchange (ETDEWEB)

    Novaes, E.; Osorio, L.; Drost, D. R.; Miles, B. L.; Boaventura-Novaes, C. R. D.; Benedict, C.; Dervinis, C.; Yu, Q.; Sykes, R.; Davis, M.; Martin, T. A.; Peter, G. F.; Kirst, M.

    2009-01-01

    The genetic control of carbon allocation and partitioning in woody perennial plants is poorly understood despite its importance for carbon sequestration, biofuels and other wood-based industries. It is also unclear how environmental cues, such as nitrogen availability, impact the genes that regulate growth, biomass allocation and wood composition in trees. 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. Sixty-three quantitative trait loci were identified for the 20 traits analyzed. The majority of quantitative trait loci 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 quantitative trait loci co-localization identified the genomic position of potential pleiotropic regulators. Pleiotropic loci linking higher growth rates to wood with less lignin are excellent targets to engineer tree germplasm improved for pulp, paper and cellulosic ethanol production. The causative genes are being identified with a genetical genomics approach.

  4. Identification and characterization of CBF/DREB1-related genes in Populus hopeiensis

    Institute of Scientific and Technical Information of China (English)

    WANG Ze-liang; AN Xin-min; LI Bo; REN Yuan-yuan; JIANG Xi-bing; BO Wen-hao; ZHANG Zhi-yi

    2008-01-01

    The dehydration-responsive element-binding factor (DREB) is a plant-specific family of transcription factors and plays an important role in plant response and adaptation to abiotic stress. In the present work, two highly similar CBF/DREBl-like genes, designated as PhCBF4a and PhCBF4b, were identified from Populus hopeiensis. These two genes contain all conserved domains known to exist in other CBF/DREBI genes. In the AP2 domain, there is only one different amino acid residue between PhCBF4a and PhCBF4b, alanine or valine, a nonpolar amino acid, suggesting that PhCBF4a and PhCBF4b may have similar DNA binding ability. Their expression is induced by water-loss treatment and their expression patterns axe similar. Moreover, with a genomic DNA as template, the presence of the same bands in PCR products as those in expression pattern analysis indicated that PhCBF4a and PhCBF4b exist in the genome of P. hopeiensis. Their detailed functions are discussed and will need further study.

  5. Genotypic Variation in Nutrient Selectivity in Populus under NaCl Stress

    Institute of Scientific and Technical Information of China (English)

    Chen Shaoliang; Bai Genben; Liu Xiangfen; Li Jinke; Wang Shasheng; Andrea Polle; Aloys Huttermann

    2003-01-01

    We used a salt-resistant poplar genotype Populus euphratica and two salt-sensitive genotypes, Populus ‘popularis35-44' (P. popularis) and the hybrid P. talassica Kom × (P. euphratica + Salix alba L.) to examine genotypic differences in nutrientselectivity under NaCl stress. One-year-old seedlings ofP. euphratica and one-year-old hardwood cuttings ofP. popularis were usedin a short-term study (24 hours), while in a long-term study, up to 4 weeks, two-year-old seedlings ofP. euphratica and the hybrid P.talassica Kom × (P. euphratica + Salix alba L.) were compared. In the short-term study, K+ concentration in the xylem sap ([K+]xylem)of P. euphratica significantly increased after salt stress was initiated, and maintained 1-2 fold higher than control levels during theperiod of salt stress (24 hours). Xylem Ca2+ and Mg2+ concentrations ([Ca2+]xylem, [Mg2+]xylem) in P. euphratica resembled the patternof K+ despite a lesser magnitude in elevation. However, [K+]xylem, [Ca2+]xylem and [Mg2+]xylem in P. popularis exhibited a transient in-crease at the beginning of salt treatment, thereafter, they all returned to control levels at 4 hours and no further rise was observed inthe following hours. Xylem Na+/K+, Na+/Ca2+ and Na+/Mg2+ in P. popularis increased sharply upon NaCl stress and steadily reachedthe maximum at 24 hours. In contrast, xylem Na+/K+, Na+/Ca2+ and Na+/Mg2+ in NaCl-treated plants of P. euphratica did not signifi-cantly increase during the period of salt stress (24 hours). Noteworthy, Na+/K+ markedly declined after the onset of stress. These re-sults suggest that P. euphratica had a higher nutrient selectivity in face of salinity. A same trend was observed in a 4-week study.Xylem Na+/K+, Na+/Ca2+ and Na+/Mg2+ in salinised plants of the hybrid abruptly increased after 4 days of stress, and then continu-ously increased to reach the highest level at day 8 or day 15. In comparison, the magnitude of Na+/K+, Na+/Ca2+ and Na+/Mg2+ eleva-tion in the xylem of P

  6. Diversification in the genetic architecture of gene expression and transcriptional networks in organ differentiation of Populus.

    Science.gov (United States)

    Drost, Derek R; Benedict, Catherine I; Berg, Arthur; Novaes, Evandro; Novaes, Carolina R D B; Yu, Qibin; Dervinis, Christopher; Maia, Jessica M; Yap, John; Miles, Brianna; Kirst, Matias

    2010-05-04

    A fundamental goal of systems biology is to identify genetic elements that contribute to complex phenotypes and to understand how they interact in networks predictive of system response to genetic variation. Few studies in plants have developed such networks, and none have examined their conservation among functionally specialized organs. Here we used genetical genomics in an interspecific hybrid population of the model hardwood plant Populus to uncover transcriptional networks in xylem, leaves, and roots. Pleiotropic eQTL hotspots were detected and used to construct coexpression networks a posteriori, for which regulators were predicted based on cis-acting expression regulation. Networks were shown to be enriched for groups of genes that function in biologically coherent processes and for cis-acting promoter motifs with known roles in regulating common groups of genes. When contrasted among xylem, leaves, and roots, transcriptional networks were frequently conserved in composition, but almost invariably regulated by different loci. Similarly, the genetic architecture of gene expression regulation is highly diversified among plant organs, with less than one-third of genes with eQTL detected in two organs being regulated by the same locus. However, colocalization in eQTL position increases to 50% when they are detected in all three organs, suggesting conservation in the genetic regulation is a function of ubiquitous expression. Genes conserved in their genetic regulation among all organs are primarily cis regulated (approximately 92%), whereas genes with eQTL in only one organ are largely trans regulated. Trans-acting regulation may therefore be the primary driver of differentiation in function between plant organs.

  7. The sucrose transporter family in Populus: the importance of a tonoplast PtaSUT4 to biomass and carbon partitioning.

    Science.gov (United States)

    Payyavula, Raja S; Tay, Kate H C; Tsai, Chung-Jui; Harding, Scott A

    2011-03-01

    Plasma membrane, proton-coupled Group II sucrose symporters (SUT) mediate apoplastic phloem loading and sucrose efflux from source leaves in Arabidopsis and agricultural crop species that have been studied to date. We now report that the most abundantly expressed SUT isoform in Populus tremula×alba, PtaSUT4, is a tonoplast (Group IV) symporter. PtaSUT4 transcripts were readily detected in conducting as well as mesophyll cells in stems and source leaves. In comparison, Group II orthologs PtaSUT1 and PtaSUT3 were very weakly expressed in leaves. Both Group II and Group IV SUT genes were expressed in secondary stem xylem of Populus. Transgenic poplars with RNAi-suppressed PtaSUT4 exhibited increased leaf-to-stem biomass ratios, elevated sucrose content in source leaves and stems, and altered phenylpropanoid metabolism. Transcript abundance of several carbohydrate-active enzymes and phenylalanine ammonia-lyases was also altered in transgenic source leaves. Nitrogen-limitation led to a down-regulation of vacuolar invertases in all plants, which resulted in an augmentation of sucrose pooling and hexose depletion in source leaves and secondary xylem of the transgenic plants. These results are consistent with a major role for PtaSUT4 in orchestrating the intracellular partitioning, and consequently, the efflux of sucrose from source leaves and the utilization of sucrose by lateral and terminal sinks. Our findings also support the idea that PtaSUT4 modulates sucrose efflux and utilization in concert with plant N-status.

  8. A novel bHLH transcription factor PebHLH35 from Populus euphratica confers drought tolerance through regulating stomatal development, photosynthesis and growth in Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Yan [College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083 (China); Liaoning Forestry Vocational-Technical College, Shenyang 110101 (China); Wang, Congpeng; Han, Xiao; Tang, Sha; Liu, Sha [College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083 (China); Xia, Xinli, E-mail: xiaxl@bjfu.edu.cn [College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083 (China); Yin, Weilun, E-mail: yinwl@bjfu.edu.cn [College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083 (China)

    2014-07-18

    Highlights: • PebHLH35 is firstly cloned from Populus euphratica and characterized its functions. • PebHLH35 is important for earlier seedling establishment and vegetative growth. • PebHLH35 enhances tolerance to drought by regulating growth. • PebHLH35 enhances tolerance to drought by regulating stomatal development. • PebHLH35 enhances tolerance to drought by regulating photosynthesis and transpiration. - Abstract: Plant basic helix-loop-helix (bHLH) transcription factors (TFs) are involved in a variety of physiological processes including the regulation of plant responses to various abiotic stresses. However, few drought-responsive bHLH family members in Populus have been reported. In this study, a novel bHLH gene (PebHLH35) was cloned from Populus euphratica. Expression analysis in P. euphratica revealed that PebHLH35 was induced by drought and abscisic acid. Subcellular localization studies using a PebHLH35-GFP fusion showed that the protein was localized to the nucleus. Ectopic overexpression of PebHLH35 in Arabidopsis resulted in a longer primary root, more leaves, and a greater leaf area under well-watered conditions compared with vector control plants. Notably, PebHLH35 overexpression lines showed enhanced tolerance to water-deficit stress. This finding was supported by anatomical and physiological analyses, which revealed a reduced stomatal density, stomatal aperture, transpiration rate, and water loss, and a higher chlorophyll content and photosynthetic rate. Our results suggest that PebHLH35 functions as a positive regulator of drought stress responses by regulating stomatal density, stomatal aperture, photosynthesis and growth.

  9. Variation of Leaf Characteristics in Populus tomentosa Carr.

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    An investigation was conducted to determine the extent of variations among nine provenances of Populus tomentosa Carr. in terms of leaf characteristics. A total of 263 accessions were studied under field conditions in the National Gene Bank of P. tomentosa in 2003. All of the accessions were characterized by 17 indices from 1 to 2-dimension constructions. Variance analysis of all characteristics showed that there were significant differences among the nine provenances and among individuals within each provenance. This study reveals that the evaluated germplasm appears to have a wide genetic base and high potential for further genetic improvements and it also indicates that abundant gene resources of P. tomentosa have been collected and preserved in the National Gene Bank.

  10. RAPD markers related to sex locus in Populus tomentosa

    Institute of Scientific and Technical Information of China (English)

    Wanwei HOU; Junfeng FAN; Feimei ZHOU; Shufang ZHAO

    2009-01-01

    By using the methods of random amplified polymorphic DNA (RAPD) and bulked segregate analysis (BSA), we identified markers that are linked to the sex determination in the dioecious Populus tomentosa. Male and female bulks were created through rough mixing equal amounts of its five individual DNA. A total of 88 primers were screened. Twelve primers produced clear patterns with at least one band that appeared to be polymorphic between the two bulks. Subsequently, five male and female individuals were analyzed with those 12 primers, and only S60 (ACCCGGTCAC) could generate a common 1800bp DNA fragment in all five male individuals and male pool but not in any female individuals. It can be concluded that the gender of P. tomentosa is most likely connected to the S60-1800bp DNA fragment and RAPD markers. S60, therefore, can be used for selecting the gender of P. tomentosa.

  11. [Application of Populus Nigra preparations at experimental parodontitis].

    Science.gov (United States)

    Kipiani, N V; Kuchukhidze, Dzh K; Chichua, Z Dzh; Kipiani, V A; Datunashvili, I V

    2007-09-01

    Severe oxidative stress, developed under experimental periodontitis is accompanied by disturbances in mitochondrial respiration in tissue cells of gingiva, membrane damage and release of Fe(2+) and Mn(2+), leading to the worsening of inflammation process and gingival tissue necrosis. Reduction of free nitric oxide in gingival tissue appeared to be characteristic for experimental parodontitis: decreases local immunity, antimicrobial resistance, and tissue regeneration, disturbs blood supply and tissue trophism, which forwards important role in deepening of inflammation process and wasting of gingival tissue. Application of preparations derived from black poplar (Populus Nigra) gemma standardizes mitochondrial respiration, reduces presentation of inflammation, and considerably improves EPR-spectrum of gingival tissue. Though the complete normalization is not achieved--hazard of peroxidation still remains, the applied preparations, due to their strong anti- oxidative and anti-inflammatory activities is as an effective and rehabilitative means to tackle gingivitis and peiodontitis.

  12. Effects of Fertilization Treatments on Plantation Growth of Triploid Clones in Populus tomentosa

    Institute of Scientific and Technical Information of China (English)

    Wang Lixian; Liu Yong; Zhang Zhiyi

    2003-01-01

    With four clones of triploid Populus tomentosa as materials, the effects of fertilization treatment on growth and physiological characters in terms of leaf nitrogen content, phosphorous content, potassium content, net photosynthetic rate, transpiration rate, water utilization efficiency and chlorophyll content have been studied. Compared with the general fertilizer as a control, the long-effect fertilizer, especially for Populus, produce more favorable results, for P. tomentosa on sandy land.

  13. Ozone-induced changes in carotenoids and chlorophylls in three Populus clones

    OpenAIRE

    Keski-Saari, Sarita; Dumont, Jennifer; Keinänen, Markku; Kontunen-Soppela, Sari; Oksanen, Elina; Le Thiec, Didier

    2011-01-01

    Ozone is a phytotoxic air pollutant causing oxidative stress. We studied the effect of ozone on carotenoids, chlorophylls and polyisoprenoid alcohols in three euramerican poplar clones (Populus deltoides x Populus nigra: 'Carpaccio', 'Cima' and 'Robusta'). Poplars originating from cuttings were grown for 6 weeks and exposed to ozone in fumigation chambers (120 ppb each day for 13h). Leaf samples were collected 2, 4, 11, 15 and 17 days after the start of ozone treatment. Chemical analyses were...

  14. Glycosylation-mediated phenylpropanoid partitioning in Populus tremuloides cell cultures

    OpenAIRE

    2009-01-01

    Abstract Background Phenylpropanoid-derived phenolic glycosides (PGs) and condensed tannins (CTs) comprise large, multi-purpose non-structural carbon sinks in Populus. A negative correlation between PG and CT concentrations has been observed in several studies. However, the molecular mechanism underlying the relationship is not known. Results Populus cell cultures produce CTs but not PGs under normal conditions. Feeding salicyl alcohol resulted in accumulation of salicins, the simplest PG, in...

  15. Photosynthesis of Populus euphratica and its response to elevated CO2 concentration in an arid environment

    Institute of Scientific and Technical Information of China (English)

    Honghua Zhou; Yaning Chen; Weihong Li; Yapeng Chen; Lixin Fu

    2009-01-01

    The photosynthetic characterization of Populus euphratica and its response to the elevated carbon dioxide concentration ([CO2]) were analyzed based on its net photosynthetic rate (Pn),stomatal conductance (gs),intercellular CO2 concentration (Ci),transpiration rate (Tr),and water use efficiency (WUE) at different groundwater depths measured by a portable gas exchange system (LI-6400) in the lower reaches of the Tarim River.The results showed that the elevation of [CO2]decreased the gs,and increased the Pn,Ci and WUE of P.euphratica.However,the effects of the elevated [CO2]on gs,Pn,Ci and WUE varied considerably with groundwater depth.The response of photosynthesis to rising [CO2]was stronger at the greater groundwater depth (more than 6 m) than that at the shallower groundwater depth (less than 6 m).The critical groundwater depth required to maintain the normal survival of P.euphratica was less than 6 m.When the groundwater depth increased to more than 6 m,P.euphratica encountered moderate water stress,and the plant suffered severe water stress when the groundwater depth increased to more than 7 m.

  16. A transcriptomic network underlies microstructural and physiological responses to cadmium in Populus x canescens.

    Science.gov (United States)

    He, Jiali; Li, Hong; Luo, Jie; Ma, Chaofeng; Li, Shaojun; Qu, Long; Gai, Ying; Jiang, Xiangning; Janz, Dennis; Polle, Andrea; Tyree, Melvin; Luo, Zhi-Bin

    2013-05-01

    Bark tissue of Populus × canescens can hyperaccumulate cadmium, but microstructural, transcriptomic, and physiological response mechanisms are poorly understood. Histochemical assays, transmission electron microscopic observations, energy-dispersive x-ray microanalysis, and transcriptomic and physiological analyses have been performed to enhance our understanding of cadmium accumulation and detoxification in P. × canescens. Cadmium was allocated to the phloem of the bark, and subcellular cadmium compartmentalization occurred mainly in vacuoles of phloem cells. Transcripts involved in microstructural alteration, changes in nutrition and primary metabolism, and stimulation of stress responses showed significantly differential expression in the bark of P. × canescens exposed to cadmium. About 48% of the differentially regulated transcripts formed a coregulation network in which 43 hub genes played a central role both in cross talk among distinct biological processes and in coordinating the transcriptomic regulation in the bark of P. × canescens in response to cadmium. The cadmium transcriptome in the bark of P. × canescens was mirrored by physiological readouts. Cadmium accumulation led to decreased total nitrogen, phosphorus, and calcium and increased sulfur in the bark. Cadmium inhibited photosynthesis, resulting in decreased carbohydrate levels. Cadmium induced oxidative stress and antioxidants, including free proline, soluble phenolics, ascorbate, and thiol compounds. These results suggest that orchestrated microstructural, transcriptomic, and physiological regulation may sustain cadmium hyperaccumulation in P. × canescens bark and provide new insights into engineering woody plants for phytoremediation.

  17. Flow regime effects on mature Populus fremontii (Fremont cottonwood) productivity on two contrasting dryland river floodplains

    Science.gov (United States)

    Andersen, Douglas C.

    2016-01-01

    I compared riparian cottonwood (Populus fremontii) productivity-discharge relationships in a relictual stand along the highly regulated Green River and in a naturally functioning stand along the unregulated Yampa River in semiarid northwest Colorado. I used multiple regression to model flow effects on annual basal area increment (BAI) from 1982 to 2011, after removing any autocorrelation present. Each BAI series was developed from 20 trees whose mean size (67 cm diameter at breast height [DBH]) was equivalent in the two stands. BAI was larger in the Yampa River stand except in 2 y when defoliating leaf beetles were present there. I found no evidence for a Yampa flood-magnitude threshold above which BAI declined. Flow variables explained ∼45% of residual BAI variability, with most explained by current-year maximum 90-d discharge (QM90) in the Yampa River stand and by a measure of the year-to-year change in QM90 in the Green River stand. The latter reflects a management-imposed ceiling on flood magnitude—Flaming Gorge Dam power plant capacity—infrequently exceeded during the study period. BAI in the relictual stand began to trend upward in 1992 when flows started to mimic a natural flow regime. Mature Fremont cottonwoods appear to be ecologically resilient. Their productivity along regulated rivers might be optimized using multiyear environmental flow designs.

  18. Changes in soil characteristics during landfill leachate irrigation of Populus deltoides.

    Science.gov (United States)

    Zupanc, Vesna; Justin, Maja Zupančič

    2010-11-01

    The effects of wastewater application on electrical conductivity, water retention and water repellency of soils planted with Populus deltoides (eastern cottonwood) and irrigated with different concentrations of landfill leachate and compost wastewater, tap water and nutrient solution were evaluated. Substrate water content at field capacity (-0.033 MPa) and at permanent wilting point (-1.5 MPa) was determined with a pressure plate extractor to assess available water capacity of the substrate. A water drop penetration test was used to determine substrate water repellency. The biomass of nutrient and landfill leachate treatments was significantly (Pwater repellency after the experiment at field capacity and permanent wilting point comparing to the original substrate. The strongest influence on water repellency at both field capacity and permanent wilting point showed irrigation with compost wastewater and tap water. Pronounced influence on substrate's water repellency of compost wastewater could be contributed to a high content of dissolved organic carbon, whereas Mg and Ca cations caused flocculation and consequent water repellency of the substrate irrigated with tap water. The results indicate that soil physical characteristics must be closely monitored when landfill leachate and compost wastewater are used for irrigation to avoid long term detrimental effects on the soil, and consequently on the environment. Due to the complexity of the compost wastewater quality the latter should be applied on open fields only after prior pre-treatment to reduce dissolved organic carbons, or alternatively, compost wastewater should be added only intermittently and in diluted ratios. Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. Identification and characterization of nuclear genes involved in photosynthesis in Populus.

    Science.gov (United States)

    Wang, Bowen; Du, Qingzhang; Yang, Xiaohui; Zhang, Deqiang

    2014-03-27

    The gap between the real and potential photosynthetic rate under field conditions suggests that photosynthesis could potentially be improved. Nuclear genes provide possible targets for improving photosynthetic efficiency. Hence, genome-wide identification and characterization of the nuclear genes affecting photosynthetic traits in woody plants would provide key insights on genetic regulation of photosynthesis and identify candidate processes for improvement of photosynthesis. Using microarray and bulked segregant analysis strategies, we identified differentially expressed nuclear genes for photosynthesis traits in a segregating population of poplar. We identified 515 differentially expressed genes in this population (FC ≥ 2 or FC ≤ 0.5, P photosynthesis by the nuclear genome mainly involves transport, metabolism and response to stimulus functions. This study provides new genome-scale strategies for the discovery of potential candidate genes affecting photosynthesis in Populus, and for identification of the functions of genes involved in regulation of photosynthesis. This work also suggests that improving photosynthetic efficiency under field conditions will require the consideration of multiple factors, such as stress responses.

  20. Identification and characterization of nuclear genes involved in photosynthesis in Populus

    Science.gov (United States)

    2014-01-01

    Background The gap between the real and potential photosynthetic rate under field conditions suggests that photosynthesis could potentially be improved. Nuclear genes provide possible targets for improving photosynthetic efficiency. Hence, genome-wide identification and characterization of the nuclear genes affecting photosynthetic traits in woody plants would provide key insights on genetic regulation of photosynthesis and identify candidate processes for improvement of photosynthesis. Results Using microarray and bulked segregant analysis strategies, we identified differentially expressed nuclear genes for photosynthesis traits in a segregating population of poplar. We identified 515 differentially expressed genes in this population (FC ≥ 2 or FC ≤ 0.5, P photosynthesis by the nuclear genome mainly involves transport, metabolism and response to stimulus functions. Conclusions This study provides new genome-scale strategies for the discovery of potential candidate genes affecting photosynthesis in Populus, and for identification of the functions of genes involved in regulation of photosynthesis. This work also suggests that improving photosynthetic efficiency under field conditions will require the consideration of multiple factors, such as stress responses. PMID:24673936

  1. The effects of exogenous putrescine on sex-specific responses of Populus cathayana to copper stress.

    Science.gov (United States)

    Chen, Lianghua; Wang, Ling; Chen, Fugui; Korpelainen, Helena; Li, Chunyang

    2013-11-01

    We used the dioecious tree, Populus cathayana, as a model species to study plants' physiological and biochemical responses to copper (Cu) stress, exogenous putrescine (Put) treatment and their interaction. Although males accumulated higher Cu concentrations in leaves than did females under Cu stress, they did not suffer more damage than females, as reflected by changes in gas exchange, pigment contents, membrane lipid peroxidation (thiobarbituric acid reactive substances, TBARS) and protein oxidation (carbonyl). Higher Cu tolerance of males was correlated with a higher H2O2 scavenging ability and proline responses, and a better maintenance of non-protein thiols (NP-SHs) and spermine (Spm) contents. We also discovered that mitigation effects of exogenous Put on Cu stress occurred, as visible as a recovery of the total chlorophyll content, and lower TBARS and carbonyl under interaction treatment when compared to Cu stress alone. Exogenous Put decreased the Cu concentration in leaves of both sexes, but to different degrees. Such effects of exogenous Put suggested that Put may play important roles in the stabilization of membrane integrity and protein structures, and it may modulate the uptake and transportation of Cu. Our results indicated that (1) males are more tolerant to Cu stress than females; (2) Put could mitigate Cu toxicity in P. cathayana, but to a different degree in males and females; (3) males are better candidates than females for Cu extraction and phytoremediation.

  2. OVER- EXPRESSION OF AN AUX1 HOMOLOG TRIGGERS OVARY INITIATION IN VITRO OF POPULUS TOMENTOSA CARR.

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    PtAUX1, an ortholog of Arabidopsis AtAUX1 ( encoding auxin influx carrier protein), has been cloned from Populus tomentosa. PtAUX1 protein is similar to Arabidopsis AtAUX1 in structure, but PtAUX1 contains an additional cAMP/cGMP - dependent protein kinase phosphorylation site. Its overexpression lines driven by 35S promoter exhibits a novel phenotype related flower development which has not been revealed in AtAUX1 mutants. Ovary - like structures each with 1 ~ 2 styles, but without a cup - like disc and a bract, can initial from regenerated transgenic bud in cluster,resembling an inflorescence. The histological dissections illuminate that the ovary - like structures have womb and transmitting tissue inner its styles, but no ovules. PtAUX1 expression pattern are ubiquitous and various in different organs,which is coincident with its candidate auxin influx, functioning in distributing auxin thorough a plant body. These results suggest that PtAUX1 or polar auxin transport has a substantial function in floral organ initiation.

  3. Expression analysis of a Na~+/H~+ antiporter gene PeNHX1 from Populus euphratica

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Na+/H+ antiporters play an important role in the salt tolerance of a wide variety of plants.Using the rapid amplification of cDNA ends method,a Na+/H+ antiporter gene (PeNHX1) was isolated from Populus euphratica.The deduced amino acid sequence contained 528 amino acid residues with a conserved amiloride-binding domain (77LFFIYLLPPI86) and shared more than 68% identity with that of AtNHX1 from Arabidopsis thaliana.PeNHX1 can confer resistance to Na+,as well as Li+,to (EP432) an Escherichia coli strain deficient in both nhaA and nhaB,thus proving that it is a functional Na+/H+ antiporter.PeNHX1 expression profile in EP432 reflected pH independent manner.PeNHX1 expression was regulated by salt at the transcriptional level.Meanwhile,results demonstrated that transcripts of PeNHX1 in P.euphratica calli showed a salt dependent response,and thus provide a valuable tool for studying signaling and biochemical pathways involved in salt recognition and response in P.euphratica.

  4. Isolation and characterization of two genes encoding polygalacturonase-inhibiting protein from Populus deltoides

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Polygalacturonase-inhibiting proteins (PGIPs) are extracellular proteins that belong to the leucine-rich repeat (LRR) protein superfamily. PGIPs inhibit fungal polygalacturonases (PGs) and promote accumulation of oligogalacturonides, which activate plant defense responses. PGIPs play important roles in resistance to infection of pathogens. In this study, reverse transcriptase-polymerase chain reaction (RT-PCR) and RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE) were used to isolate the full-length PGIP cDNA from Populus deltoides (GenBank accession no. Of PdPGIP2 and PdPGIP4:EF684913 and EF684912). Domain analysis revealed that the deduced amino acid sequences of PdPGIP2 and PdPGIP4 had a typical POIP topology. Phylogenetic analysis of known PGIPs indicated that the two PdPGIPs were clustered to the defense-related PGIP clade. Using real-time RT-PCR, the expression patterns of the two PdPGIPs following treatment with a fungal pathogen and defense-related signaling molecules were studied. The expression levels of PdPGIP2 and PdPGIP4 were both up-regulated when inoculated with the phytopathogenic fungus Marssonina brunnea. Therefore, it was proposed that the two PGIPs might be involved in the resistance to Marssonina brunnea in P. Deltoides.

  5. Influences of the Populus deltoids seedlings treated with exogenous methyl jasmonate on the growth and development of Lymantria dispar larvae

    Institute of Scientific and Technical Information of China (English)

    HU Zeng-hui; ZHAO Ling; YANG Di; SHEN Ying-bai; SHEN Fan-yi

    2006-01-01

    Lyantria dispar larvae were fed with the leaves of Populus deltoids seedlings exposed to methyl jasmonate (MeJA) for 24 h. The growth and development of the larvae were investigated, and phenolics contents in treated leaves including pyrocatechol, caffeic acid, coumarin, ferulic acid and benzoic acid were also surveyed by high-pressure liquid chromatography (HPLC). Results indicated that approximate digestibility, efficiency of conversion of ingested food, efficiency of conversion of digested food, and weight of the larvae were inhibited obviously, especially from the sixth day, which may result from the increase of total phenolics contents in treated leaves. This result provides strong supports for MeJA acting as the airborne signal molecule between woody plants.

  6. Distinct Microbial Communities within the Endosphere and Rhizosphere of Populus deltoides Roots across Contrasting Soil Types ▿†

    Science.gov (United States)

    Gottel, Neil R.; Castro, Hector F.; Kerley, Marilyn; Yang, Zamin; Pelletier, Dale A.; Podar, Mircea; Karpinets, Tatiana; Uberbacher, Ed; Tuskan, Gerald A.; Vilgalys, Rytas; Doktycz, Mitchel J.; Schadt, Christopher W.

    2011-01-01

    The root-rhizosphere interface of Populus is the nexus of a variety of associations between bacteria, fungi, and the host plant and an ideal model for studying interactions between plants and microorganisms. However, such studies have generally been confined to greenhouse and plantation systems. Here we analyze microbial communities from the root endophytic and rhizospheric habitats of Populus deltoides in mature natural trees from both upland and bottomland sites in central Tennessee. Community profiling utilized 454 pyrosequencing with separate primers targeting the V4 region for bacterial 16S rRNA and the D1/D2 region for fungal 28S rRNA genes. Rhizosphere bacteria were dominated by Acidobacteria (31%) and Alphaproteobacteria (30%), whereas most endophytes were from the Gammaproteobacteria (54%) as well as Alphaproteobacteria (23%). A single Pseudomonas-like operational taxonomic unit (OTU) accounted for 34% of endophytic bacterial sequences. Endophytic bacterial richness was also highly variable and 10-fold lower than in rhizosphere samples originating from the same roots. Fungal rhizosphere and endophyte samples had approximately equal amounts of the Pezizomycotina (40%), while the Agaricomycotina were more abundant in the rhizosphere (34%) than endosphere (17%). Both fungal and bacterial rhizosphere samples were highly clustered compared to the more variable endophyte samples in a UniFrac principal coordinates analysis, regardless of upland or bottomland site origin. Hierarchical clustering of OTU relative abundance patterns also showed that the most abundant bacterial and fungal OTUs tended to be dominant in either the endophyte or rhizosphere samples but not both. Together, these findings demonstrate that root endophytic communities are distinct assemblages rather than opportunistic subsets of the rhizosphere. PMID:21764952

  7. Influence of Genotype, Environment, and Gypsy Moth Herbivory on Local and Systemic Chemical Defenses in Trembling Aspen (Populus tremuloides).

    Science.gov (United States)

    Rubert-Nason, Kennedy F; Couture, John J; Major, Ian T; Constabel, C Peter; Lindroth, Richard L

    2015-07-01

    Numerous studies have explored the impacts of intraspecific genetic variation and environment on the induction of plant chemical defenses by herbivory. Relatively few, however, have considered how those factors affect within-plant distribution of induced defenses. This work examined the impacts of plant genotype and soil nutrients on the local and systemic phytochemical responses of trembling aspen (Populus tremuloides) to defoliation by gypsy moth (Lymantria dispar). We deployed larvae onto foliage on individual tree branches for 15 days and then measured chemistry in leaves from: 1) branches receiving damage, 2) undamaged branches of insect-damaged trees, and 3) branches of undamaged control trees. The relationship between post-herbivory phytochemical variation and insect performance also was examined. Plant genotype, soil nutrients, and damage all influenced phytochemistry, with genotype and soil nutrients being stronger determinants than damage. Generally, insect damage decreased foliar nitrogen, increased levels of salicinoids and condensed tannins, but had little effect on levels of a Kunitz trypsin inhibitor, TI3. The largest damage-mediated tannin increases occurred in leaves on branches receiving damage, whereas the largest salicinoid increases occurred in leaves of adjacent, undamaged branches. Foliar nitrogen and the salicinoid tremulacin had the strongest positive and negative relationships, respectively, with insect growth. Overall, plant genetics and environment concomitantly influenced both local and systemic phytochemical responses to herbivory. These findings suggest that herbivory can contribute to phytochemical heterogeneity in aspen foliage, which may in turn influence future patterns of herbivory and nutrient cycling over larger spatial scales.

  8. Protein (Viridiplantae): 613798 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 601 3688:1895 ... 238069:1895 ... 3689:1895 ... 3694:1895 ... hypothetical protein POPTR_0005s01830g Populus trichocarpa MARIFRGNETQANTDRIVGAHGYMSPEYAMEGLFSIKSDVFSFGLLVLEIVSAGASSVTNVTITAIDAR

  9. Protein (Viridiplantae): 761681 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 3688:2831 ... 238069:2831 ... 3689:2831 ... 3694:2831 ... caprice family protein Populus trichocarpa MDRRRKKQAKTTSCCSEQEVSSIEWEFINMSEQEEDLIYRMHNLVGDRWALIAGRIPGRKAEEIERFWLMRHGEGFASRRREQKRCHS

  10. Protein (Viridiplantae): 400303 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 19 3688:327 ... 238069:327 ... 3689:327 ... 3694:327 ... zinc finger family protein Populus trichocarpa MKGCELCGSSARM...FCESDEASLCWDCDEKVHSANFLVAKHCRTLLCQVCQSPTPWKASVSKFAPTVSICESCFTIPNKTKETEERMKGCELCGSSARM

  11. The Populus superoxide dismutase gene family and its responses to drought stress in transgenic poplar overexpressing a pine cytosolic glutamine synthetase (GS1a.

    Directory of Open Access Journals (Sweden)

    Juan Jesús Molina-Rueda

    Full Text Available BACKGROUND: Glutamine synthetase (GS plays a central role in plant nitrogen assimilation, a process intimately linked to soil water availability. We previously showed that hybrid poplar (Populus tremula X alba, INRA 717-1B4 expressing ectopically a pine cytosolic glutamine synthetase gene (GS1a display enhanced tolerance to drought. Preliminary transcriptome profiling revealed that during drought, members of the superoxide dismutase (SOD family were reciprocally regulated in GS poplar when compared with the wild-type control, in all tissues examined. SOD was the only gene family found to exhibit such patterns. RESULTS: In silico analysis of the Populus genome identified 12 SOD genes and two genes encoding copper chaperones for SOD (CCSs. The poplar SODs form three phylogenetic clusters in accordance with their distinct metal co-factor requirements and gene structure. Nearly all poplar SODs and CCSs are present in duplicate derived from whole genome duplication, in sharp contrast to their predominantly single-copy Arabidopsis orthologs. Drought stress triggered plant-wide down-regulation of the plastidic copper SODs (CSDs, with concomitant up-regulation of plastidic iron SODs (FSDs in GS poplar relative to the wild type; this was confirmed at the activity level. We also found evidence for coordinated down-regulation of other copper proteins, including plastidic CCSs and polyphenol oxidases, in GS poplar under drought conditions. CONCLUSIONS: Both gene duplication and expression divergence have contributed to the expansion and transcriptional diversity of the Populus SOD/CCS families. Coordinated down-regulation of major copper proteins in drought-tolerant GS poplars supports the copper cofactor economy model where copper supply is preferentially allocated for plastocyanins to sustain photosynthesis during drought. Our results also extend previous findings on the compensatory regulation between chloroplastic CSDs and FSDs, and suggest that this

  12. Sex-specific responses of Populus yunnanensis exposed to elevated CO{sub 2} and salinity

    Energy Technology Data Exchange (ETDEWEB)

    Ling Li; Yuanbin Zhang; Chunyang Li [Chinese Academy of Sciences. Chengdu Institute of Biology, Chengdu (Switzerland); Jianxun Luo, Sichuan Academy of Forestry, Chengdu (Switzerland)); Korpelainen, H. [Univ. of Helsinki. Dept. of Agricultural Sciences, Helsinki (Finland)

    2013-04-15

    Populus yunnanensis Dode., a native dioecious woody plant in southwestern China, was employed as a model species to study sex-specific morphological, physiological and biochemical responses to elevated CO{sub 2} and salinity. To investigate the effects of elevated CO{sub 2}, salinity and their combination, the cuttings were exposed to two CO{sub 2} regimes (ambient CO{sub 2} and double ambient CO{sub 2}) and two salt treatments in growth chambers. Males exhibited greater downregulation of net photosynthesis rate (A{sub net}) and carboxylation efficiency (CE) than females at elevated CO{sub 2}, whereas these sexual differences were lessened under salt stress. On the other hand, salinity induced a higher decrease in Anet and CE, more growth inhibition and leaf Cl{sup -} accumulation and more damage to cell organelles in females than in males, whereas the sexual differences in photosynthesis and growth were lessened at elevated CO{sub 2}. Moreover, elevated CO{sub 2} exacerbated membrane lipid peroxidation and organelle damage in females but not in males under salt stress. Our results indicated that: (1) females are more sensitive and suffer from greater negative effects than do males under salt stress, and elevated CO{sub 2} lessens the sexual differences in photosynthesis and growth under salt stress; (2) elevated CO{sub 2} tends to aggravate the negative effects of salinity in females; and (3) sex-specific reactions under the combination of elevated CO{sub 2} and salinity are distinct from single-stress responses. Therefore, these results provide evidence for different adaptive responses between plants of different sexes exposed to elevated CO{sub 2} and salinity. (Author)

  13. Genetic differentiation and delimitation between ecologically diverged Populus euphratica and P. pruinosa.

    Directory of Open Access Journals (Sweden)

    Juan Wang

    Full Text Available BACKGROUND: The fixed genetic differences between ecologically divergent species were found to change greatly depending on the markers examined. With such species it is difficult to differentiate between shared ancestral polymorphisms and past introgressions between the diverging species. In order to disentangle these possibilities and provide a further case for DNA barcoding of plants, we examine genetic differentiation between two ecologically divergent poplar species, Populus euphratica Oliver and P. pruinosa Schrenk using three different types of genetic marker. METHODOLOGY/PRINCIPAL FINDINGS: We genotyped 290 individuals from 29 allopatric and sympatric populations, using chloroplast (cp DNA, nuclear (nr ITS sequences and eight simple sequence repeat (SSR loci. Three major cpDNA haplotypes were widely shared between the two species and between-species cpDNA differentiation (F(CT was very low, even lower than among single species populations. The average SSR F(CT values were higher. Bayesian clustering analysis of all loci allowed a clear delineation of the two species. Gene flow, determined by examining all SSR loci, was obvious but only slightly asymmetrical. However, the two species were almost fixed for two different nrITS genotypes that had the highest F(CT, although a few introgressed individuals were detected both in allopatric and sympatric populations. CONCLUSIONS: The two species shared numerous ancestral polymorphisms at cpDNA and a few SSR loci. Both ITS and a combination of nuclear SSR data could be used to differentiate between the two species. Introgressions and gene flow were obvious between the two species either during or after their divergence. Our findings underscore the complex genetic differentiations between ecologically diverged species and highlight the importance of nuclear DNA (especially ITS differentiation for delimiting closely related plant species.

  14. Phylogeny and expression profiling of CAD and CAD-like genes in hybrid Populus (P. deltoides × P. nigra: evidence from herbivore damage for subfunctionalization and functional divergence

    Directory of Open Access Journals (Sweden)

    Frost Christopher J

    2010-05-01

    Full Text Available Abstract Background Cinnamyl Alcohol Dehydrogenase (CAD proteins function in lignin biosynthesis and play a critical role in wood development and plant defense against stresses. Previous phylogenetic studies did not include genes from seedless plants and did not reflect the deep evolutionary history of this gene family. We reanalyzed the phylogeny of CAD and CAD-like genes using a representative dataset including lycophyte and bryophyte sequences. Many CAD/CAD-like genes do not seem to be associated with wood development under normal growth conditions. To gain insight into the functional evolution of CAD/CAD-like genes, we analyzed their expression in Populus plant tissues in response to feeding damage by gypsy moth larvae (Lymantria dispar L.. Expression of CAD/CAD-like genes in Populus tissues (xylem, leaves, and barks was analyzed in herbivore-treated and non-treated plants by real time quantitative RT-PCR. Results CAD family genes were distributed in three classes based on sequence conservation. All the three classes are represented by seedless as well as seed plants, including the class of bona fide lignin pathway genes. The expression of some CAD/CAD-like genes that are not associated with xylem development were induced following herbivore damage in leaves, while other genes were induced in only bark or xylem tissues. Five of the CAD/CAD-like genes, however, showed a shift in expression from one tissue to another between non-treated and herbivore-treated plants. Systemic expression of the CAD/CAD-like genes was generally suppressed. Conclusions Our results indicated a correlation between the evolution of the CAD gene family and lignin and that the three classes of genes may have evolved in the ancestor of land plants. Our results also suggest that the CAD/CAD-like genes have evolved a diversity of expression profiles and potentially different functions, but that they are nonetheless co-regulated under stress conditions.

  15. Populus yunnanensis males adopt more efficient protective strategies than females to cope with excess zinc and acid rain.

    Science.gov (United States)

    Jiang, Hao; Korpelainen, Helena; Li, Chunyang

    2013-05-01

    Dioecious plants show sexually different responses to environmental stresses. However, little is known about the dimorphic morphological and physiological responses to soil pollution. To investigate sex-related adaptive responses of Populus yunnanensis seedlings when exposed to excess zinc (Zn), acid rain (AR) and their combination (Zn+AR), we analyzed growth parameters, Zn accumulation and allocation, photosynthetic capacity and biochemical responses under different treatments. Results revealed that both excess Zn and Zn+AR have a negative effect on plant growth. Males have a greater potential than females to enrich Zn. The photosynthesis limitation could be attributable to a lower stomatal conductance, photosynthetic nitrogen use efficiency and nitrate reductase activity induced by Zn accumulation. Overproduction of reactive oxygen species was detected, and females showed higher levels of H2O2 and O2- than did males under excess Zn and Zn+AR. In addition, indicators related to plant injury showed expected increases and exhibited sexual differences. Males synthesized more biochemical molecules, such as proline and non-protein thiol, showing a stronger defense capacity in responses to either excess Zn or Zn+AR. Taking into account the Zn accumulation and the resulting injuries in plants, we suggest that excess Zn causes sex-related adaptive responses and males possess a more effective self-protection mechanism, Zn-stressed individuals suffering from AR did not show notable aggravation or alleviation when compared to damages induced by excess Zn alone.

  16. Stacked propagation: a new way to grow native plants from root cuttings

    Science.gov (United States)

    David R. Dreesen; Thomas D. Landis; Jeremy R. Pinto

    2006-01-01

    Stacked propagation is a novel method of growing quaking aspen (Populus tremuloides Michx. [Salicaceae]) and other plants that reproduce from underground stems or root cuttings. Because the mother plant is not damaged, it is particularly well suited for rare plants or those that can’t be propagated by normal methods. Our initial trials indicate that...

  17. CHANGES OF CUTICLE SURFACE LIPIDS OF POPULUS ITALICA AND BETULA PENDULA CAUSED BY POLLUTION

    Directory of Open Access Journals (Sweden)

    O. M. Zubrovskaya

    2014-08-01

    Full Text Available Arboreal plants intensively accumulate heavy metals, resulting in a corresponding revocation level of physiological processes. The lipid components operate an important role in the formation of plant resistance. Therefore, it was very important to determine the characteristics of lipid peroxidation flow in leaves of arboreal plants, and changes in the composition of cuticle surface lipids at different levels of heavy metal accumulation. Research objects were Populus italica (Du Roi Moench and Betula pendula Roth. of second age group, growing on the industrial site РJSC ‘Kryvyi Rig Factory of minium’ (with strong contamination and in the arboretum of Kryvyi Rig Botanic Garden, National Academy of Science of Ukraine (conventional control. Leaves were taken from the middle of the crown southwest exposure in phase of leaf full separation and 5-10 day of phase finishing point of their growth. It was shown that P. italica maximally accumulated zinc, content of which was increased in the phase of leaf full separation and on 5-10 day of phase of leaf growth finishing point relative to the control to 12,6 and 23 times respectively. The accumulation level of heavy metals was typically less significant for assimilation organs of B. pendula compared to P. italica. Thus, the content of zinc and lead in the leaves during the study increased only in 2 times towards control. The leaves of B. pendula, unlike P. italica, more intensively accumulated cadmium in the phase of leaf full separation and on 5-10 day of phase finishing point of their growth (it was 6 and 15 times higher relative to control respectively. It was obviously connected to the fact that the surface texture of poplar leaves may cause intense sticking of dust particles containing heavy metals and penetration into the leaves. The effect of heavy metals in both phases of leaf morphogenesis caused an increase in lipid peroxidation by 40-52% for P. italica and almost by 3 times for B

  18. Allelic variation in PtoPsbW associated with photosynthesis, growth, and wood properties in Populus tomentosa.

    Science.gov (United States)

    Wang, Longxin; Wang, Bowen; Du, Qingzhang; Chen, Jinhui; Tian, Jiaxing; Yang, Xiaohui; Zhang, Deqiang

    2017-02-01

    Photosynthesis is one of the most important reactions on earth. PsbW, a nuclear-encoded subunit of photosystem II (PSII), stabilizes PSII structure and plays an important role in photosynthesis. Here, we used candidate gene-based linkage disequilibrium (LD) mapping to detect significant associations between allelic variations of PtoPsbW and traits related to photosynthesis, growth, and wood properties in Populus tomentosa. PtoPsbW showed the highest expression in leaves and it increased during the development of these leaves, suggesting that PtoPsbW may play an important role in plant growth and development. Analysis of nucleotide diversity and LD revealed that PtoPsbW has low single-nucleotide polymorphism (SNP) diversity (π tot = 0.0048 and θ w = 0.0050) and relatively low average value of LD (0.1500), indicating that PtoPsbW is conserved due to its indispensable function. Using single-SNP associations in an association population of 435 individuals, we identified five significant associations at the threshold of P ≤ 0.05, explaining 3.28-15.98 % of the phenotypic variation. Haplotype-based association analyses indicated that 13 haplotypes (P ≤ 0.05) from six blocks were associated with photosynthesis, growth, and wood properties. Our work shows that identifying allelic variation and LD can help to decipher the genetic basis of photosynthesis and could potentially be applied for molecular marker-assisted selection in Populus.

  19. Lignin Characterization of Triploid Clones of Populus tomentosa Carr.

    Institute of Scientific and Technical Information of China (English)

    Jin Xiao-juan; Pu Jun-wen; Xie Yi-min; Takeshi Furuno; Liu Xin-yu

    2005-01-01

    In order to understand the structural characteristics of lignin in triploid clones ofPopulus tomentosa and its changes in the processes of pulping and bleaching, milled wood lignin (MWL), lignin carbohydrate complex (LCC) and the residual lignin from kraft pulp (KP) and sulfite pulp (SP) were isolated and analyzed by Fourier transform infrared (FTIR) spectrum and 13C nuclear magnetic resonance (NMR). The most diagnostic peaks were assigned and the differences were discussed. The spectral patterns reveal that triploid P. tomentosa shows the specific features of hardwood from temperate areas, but in the spectrum of FTIR, the strength ratio of A1270 cm-1 to A1226 cm-1 is 0.88, higher than the average of hardwood from temperate areas, which will make the lignin delignification more difficult during pulping and bleaching. The LCC from triploid P. tomentosa is mainly composed of xyloglucan and glucuronic acid, and other glucides have much lower ratio. In LCC FTIR, there are three peaks at 1 427, 1 329 and 1046 cm--1, indicating that both semi-cellulose and cellulose could exist in LCC, and that there might be relationships between cellulose and lignin. Compared with the residual lignin from KP and SP, the condensed structure in KP is more than that in SP.

  20. Construction of cDNA Library from Populus euphratica

    Institute of Scientific and Technical Information of China (English)

    Yu Guangjun; Wang Yiqin; Shen Xin

    2003-01-01

    In order to isolate and clone salt-tolerance involved genes of Populus euphratica, we constructed a cDNA library from salt-treated leaves of P. euphratica. In the experiment, double strand cDNA were synthesized by a beads-based method. The syntheses of the first strand and the second strand cDNA, adapter ligation and restriction reaction for releasing cDNA were all conducted on the beads. The double strand cDNA were released from magnetic beads by digestion with NotI, and cDNA fragments smaller than 500 bp and residual adapters were removed through cDNA size fractionation columns. Finally, double strand cDNA were directionally cloned intoλExcell vector. The results show that the primary titer of the cDNA library is 7.46×106 pfu per mL and the packaging efficiency reaches 1.47×107 recombinants per μg DNA. λDNA extracted from two clones of plaque were digested by EcoR I and NotI, both of the clones contained inserts larger than 900 bp. These results show that the cDNA library of salt-treated P. euphratica leaves has been successfully constructed.

  1. The Populus ARBORKNOX1 homeodomain transcription factor regulates woody growth through binding to evolutionarily conserved target genes of diverse function

    Science.gov (United States)

    Lijun Liu; Matthew S. Zinkgraf; H. Earl Petzold; Eric P. Beers; Vladimir Filkov; Andrew Groover

    2014-01-01

    The class I KNOX homeodomain transcription factor ARBORKNOX1 (ARK1) is a key regulator of vascular cambium maintenance and cell differentiation in Populus. Currently, basic information is lacking concerning the distribution, functional characteristics, and evolution of ARK1 binding in the Populus genome.

  2. Sodium and chloride accumulation in leaf, woody, and root tissue of Populus after irrigation with landfill leachate

    Science.gov (United States)

    Jill A. Zalesny; Ronald S., Jr. Zalesny; Adam H. Wiese; Bart Sexton; Richard B. Hall

    2008-01-01

    The response of Populus to irrigation sources containing elevated levels of sodium (Na+) and chloride (Cl-) is poorly understood. We irrigated eight Populus clones with fertilized well water (control) (N, P, K) or municipal solid waste landfill leachate weekly during 2005 and 2006 in...

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

    Directory of Open Access Journals (Sweden)

    Giorgia Carletti

    Full Text Available 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.

  4. The Populus Class III HD ZIP transcription factor POPCORONA affects cell differentiation during secondary growth of woody stems.

    Science.gov (United States)

    Du, Juan; Miura, Eriko; Robischon, Marcel; Martinez, Ciera; Groover, Andrew

    2011-02-28

    The developmental mechanisms regulating cell differentiation and patterning during the secondary growth of woody tissues are poorly understood. Class III HD ZIP transcription factors are evolutionarily ancient and play fundamental roles in various aspects of plant development. Here we investigate the role of a Class III HD ZIP transcription factor, POPCORONA, during secondary growth of woody stems. Transgenic Populus (poplar) trees expressing either a miRNA-resistant POPCORONA or a synthetic miRNA targeting POPCORONA were used to infer function of POPCORONA during secondary growth. Whole plant, histological, and gene expression changes were compared for transgenic and wild-type control plants. Synthetic miRNA knock down of POPCORONA results in abnormal lignification in cells of the pith, while overexpression of a miRNA-resistant POPCORONA results in delayed lignification of xylem and phloem fibers during secondary growth. POPCORONA misexpression also results in coordinated changes in expression of genes within a previously described transcriptional network regulating cell differentiation and cell wall biosynthesis, and hormone-related genes associated with fiber differentiation. POPCORONA illustrates another function of Class III HD ZIPs: regulating cell differentiation during secondary growth.

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

    Directory of Open Access Journals (Sweden)

    Yunqiang Yang

    Full Text Available 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.

  6. Transgenic modification of gai or rg/1 causes dwarfing and alters gibberellins, root growth, and metabolite profiles in Populus

    Energy Technology Data Exchange (ETDEWEB)

    Tschaplinski, Timothy J [ORNL; Busov, V. [Michigan Technological University; Meilan, R [Purdue University; Pearce, D [University of Lethbridge; Rood, s [University of Lethbridge; Ma, C [Oregon State University; Strauss, S [Oregon State University

    2006-01-01

    In Arabidopsis and other plants, gibberellin (GA)-regulated responses are mediated by proteins including GAI, RGA and RGL1-3 that contain a functional DELLA domain. Through transgenic modification, we found that DELLA-less versions of GAI (gai) and RGL1 (rgl1) in a Populus tree have profound, dominant effects on phenotype, producing pleiotropic changes in morphology and metabolic profiles. Shoots were dwarfed, likely via constitutive repression of GA-induced elongation, whereas root growth was promoted two- to threefold in vitro. Applied GA{sub 3} inhibited adventitious root production in wild-type poplar, but gai/rgl1 poplars were unaffected by the inhibition. The concentrations of bioactive GA{sub 1} and GA{sub 4} in leaves of gai- and rgl1-expressing plants increased 12- to 64-fold, while the C{sub 19} precursors of GA{sub 1} (GA{sub 53}, GA{sub 44} and GA{sub 19}) decreased three- to ninefold, consistent with feedback regulation of GA 20-oxidase in the transgenic plants. The transgenic modifications elicited significant metabolic changes. In roots, metabolic profiling suggested increased respiration as a possible mechanism of the increased root growth. In leaves, we found metabolite changes suggesting reduced carbon flux through the lignin biosynthetic pathway and a shift towards allocation of secondary storage and defense metabolites, including various phenols, phenolic glucosides, and phenolic acid conjugates.

  7. Altering carbon allocation in hybrid poplar (Populus alba × grandidentata) impacts cell wall growth and development.

    Science.gov (United States)

    Unda, Faride; Kim, Hoon; Hefer, Charles; Ralph, John; Mansfield, Shawn D

    2016-12-20

    Galactinol synthase is a pivotal enzyme involved in the synthesis of the raffinose family of oligosaccharides (RFOs) that function as transport carbohydrates in the phloem, as storage compounds in sink tissues and as soluble metabolites that combat both abiotic and biotic stress in several plant species. Hybrid poplar (Populus alba × grandidentata) overexpressing the Arabidopsis thaliana GolS3 (AtGolS3) gene showed clear effects on development; the extreme overexpressing lines were stunted and had cell wall traits characteristic of tension wood, whereas lines with only moderate up-regulation grew normally and had moderately altered secondary cell wall composition and ultrastructure. Stem cross-sections of the developing xylem revealed a significant increase in the number of vessels, as well as the clear presence of a G-layer in the fibres. Furthermore, AtGolS3-OE lines possessed higher cellulose and lower lignin contents, an increase in cellulose crystallinity, and significantly altered hemicellulose-derived carbohydrates, notably manifested by their mannose and xylose contents. In addition, the transgenic plants displayed elevated xylem starch content. Transcriptome interrogation of the transgenic plants showed a significant up-regulation of genes involved in the synthesis of myo-inositol, along with genes involved in sucrose degradation. The results suggest that the overexpression of GolS and its product galactinol may serve as a molecular signal that initiates metabolic changes, culminating in a change in cell wall development and potentially the formation of tension wood.

  8. [Hydraulic limitation on photosynthetic rate of old Populus simonii trees in sandy soil of north Shaanxi Province].

    Science.gov (United States)

    Zuo, Li-Xiang; Li, Yang-Yang; Chen, Jia-Cun

    2014-06-01

    'Old and dwarf trees' on the loess plateau region mainly occurred among mature trees rather than among small trees. To elucidate the mechanism of tree age on 'old and dwarf trees' formation, taking Populus simonii, a tree species that accounted for the largest portion of 'old and dwarf trees' on the loess plateau, as an example, the growth, photosynthesis and hydraulic traits of P. simonii trees with different ages (young: 13-15 years, mid-aged: 31-34 years, and old: 49-54 years) were measured. The results showed that the dieback length increased, and net photosynthetic rate, stomatal conductance, transpiration rate, and whole plant hydraulic conductance decreased significantly with the increasing tree age. Both net photosynthetic rate and stomatal conductance measured at different dates were significantly and positively related to the whole plant hydraulic conductance, suggesting that the decreasing photosynthetic rate of old trees was possibly caused by the declined hydraulic conductance. Although the resistance to cavitation in stems and leaves was stronger in old trees than in young and mid-aged trees, there were no differences in midday native stem embolization degree and leaf hydraulic conductance based on the vulnerability curve estimation, suggesting that the increased hydraulic resistance of the soil-root system is probably the most important reason for decreasing the whole plant hydraulic conductance of old trees.

  9. A Carotenoid-Deficient Mutant in Pantoea sp. YR343, a Bacteria Isolated from the Rhizosphere of Populus deltoides, Is Defective in Root Colonization

    Science.gov (United States)

    Bible, Amber N.; Fletcher, Sarah J.; Pelletier, Dale A.; Schadt, Christopher W.; Jawdy, Sara S.; Weston, David J.; Engle, Nancy L.; Tschaplinski, Timothy; Masyuko, Rachel; Polisetti, Sneha; Bohn, Paul W.; Coutinho, Teresa A.; Doktycz, Mitchel J.; Morrell-Falvey, Jennifer L.

    2016-01-01

    The complex interactions between plants and their microbiome can have a profound effect on the health and productivity of the plant host. A better understanding of the microbial mechanisms that promote plant health and stress tolerance will enable strategies for improving the productivity of economically important plants. Pantoea sp. YR343 is a motile, rod-shaped bacterium isolated from the roots of Populus deltoides that possesses the ability to solubilize phosphate and produce the phytohormone indole-3-acetic acid (IAA). Pantoea sp. YR343 readily colonizes plant roots and does not appear to be pathogenic when applied to the leaves or roots of selected plant hosts. To better understand the molecular mechanisms involved in plant association and rhizosphere survival by Pantoea sp. YR343, we constructed a mutant in which the crtB gene encoding phytoene synthase was deleted. Phytoene synthase is responsible for converting geranylgeranyl pyrophosphate to phytoene, an important precursor to the production of carotenoids. As predicted, the ΔcrtB mutant is defective in carotenoid production, and shows increased sensitivity to oxidative stress. Moreover, we find that the ΔcrtB mutant is impaired in biofilm formation and production of IAA. Finally we demonstrate that the ΔcrtB mutant shows reduced colonization of plant roots. Taken together, these data suggest that carotenoids are important for plant association and/or rhizosphere survival in Pantoea sp. YR343. PMID:27148182

  10. A carotenoid-deficient mutant in Pantoea sp. YR343, a bacteria isolated from the rhizosphere of Populus deltoides, is defective in root colonization

    Directory of Open Access Journals (Sweden)

    Amber N Bible

    2016-04-01

    Full Text Available The complex interactions between plants and their microbiome can have a profound effect on the health and productivity of the plant host. A better understanding of the microbial mechanisms that promote plant health and stress tolerance will enable strategies for improving the productivity of economically-important plants. Pantoea sp. YR343 is a motile, rod-shaped bacterium isolated from the roots of Populus deltoides that possesses the ability to solubilize phosphate and produce the phytohormone indole-3-acetic acid. Pantoea sp. YR343 readily colonizes plant roots and does not appear to be pathogenic when applied to the leaves or roots of selected plant hosts. To better understand the molecular mechanisms involved in plant association and rhizosphere survival by Pantoea sp. YR343, we constructed a mutant in which the crtB gene encoding phytoene synthase was deleted. Phytoene synthase is responsible for converting geranylgeranyl pyrophosphate to phytoene, an important precursor to the production of carotenoids. As predicted, the ΔcrtB mutant is defective in carotenoid production, and shows increased sensitivity to oxidative stress. Moreover, we find that the ΔcrtB mutant is impaired in biofilm formation and production of indole-3-acetic acid. Finally we demonstrate that the ΔcrtB mutant shows reduced colonization of plant roots. Taken together, these data suggest that carotenoids are important for plant association and/or rhizosphere survival in Pantoea sp. YR343.

  11. Down-regulation of KORRIGAN-like endo-β-1,4-glucanase genes impacts carbon partitioning, mycorrhizal colonization and biomass production in Populus

    Directory of Open Access Journals (Sweden)

    Udaya C Kalluri

    2016-10-01

    Full Text Available A greater understanding of the genetic regulation of plant cell wall remodeling and the impact of modified cell walls on plant performance is important for the development of sustainable biofuel crops. Here, we studied the impact of down-regulating KORRIGAN-like cell wall biosynthesis genes, belonging to the endo-β-1,4-glucanase gene family, on Populus growth, metabolism and the ability to interact with symbiotic microbes. The reductions in cellulose content and lignin syringyl-to-guaiacyl unit ratio, and increase in cellulose crystallinity of cell walls of PdKOR RNAi plants corroborated the functional role of PdKOR in cell wall biosynthesis. Altered metabolism and reduced growth characteristics of RNAi plants revealed new implications on carbon allocation and partitioning. The distinctive metabolome phenotype comprised of a higher phenolic and salicylic acid content, and reduced lignin, shikimic acid and maleic acid content relative to control. Plant sustainability implications of modified cell walls on beneficial plant-microbe interactions were explored via co-culture with an ectomycorrhizal fungus, Laccaria bicolor. A significant increase in the mycorrhization rate was observed in transgenic plants, leading to measurable beneficial growth effects. These findings present new evidence for functional interconnectedness of cellulose biosynthesis pathway, metabolism and mycorrhizal association in plants, and further emphasize the consideration of the sustainability implications of plant trait improvement efforts.

  12. Down-Regulation of KORRIGAN-Like Endo-β-1,4-Glucanase Genes Impacts Carbon Partitioning, Mycorrhizal Colonization and Biomass Production in Populus

    Science.gov (United States)

    Kalluri, Udaya C.; Payyavula, Raja S.; Labbé, Jessy L.; Engle, Nancy; Bali, Garima; Jawdy, Sara S.; Sykes, Robert W.; Davis, Mark; Ragauskas, Arthur; Tuskan, Gerald A.; Tschaplinski, Timothy J.

    2016-01-01

    A greater understanding of the genetic regulation of plant cell wall remodeling and the impact of modified cell walls on plant performance is important for the development of sustainable biofuel crops. Here, we studied the impact of down-regulating KORRIGAN-like cell wall biosynthesis genes, belonging to the endo-β-1,4-glucanase gene family, on Populus growth, metabolism and the ability to interact with symbiotic microbes. The reductions in cellulose content and lignin syringyl-to-guaiacyl unit ratio, and increase in cellulose crystallinity of cell walls of PdKOR RNAi plants corroborated the functional role of PdKOR in cell wall biosynthesis. Altered metabolism and reduced growth characteristics of RNAi plants revealed new implications on carbon allocation and partitioning. The distinctive metabolome phenotype comprised of a higher phenolic and salicylic acid content, and reduced lignin, shikimic acid and maleic acid content relative to control. Plant sustainability implications of modified cell walls on beneficial plant-microbe interactions were explored via co-culture with an ectomycorrhizal fungus, Laccaria bicolor. A significant increase in the mycorrhization rate was observed in transgenic plants, leading to measurable beneficial growth effects. These findings present new evidence for functional interconnectedness of cellulose biosynthesis pathway, metabolism and mycorrhizal association in plants, and further emphasize the consideration of the sustainability implications of plant trait improvement efforts. PMID:27757116

  13. Genetic variations and miRNA-target interactions contribute to natural phenotypic variations in Populus.

    Science.gov (United States)

    Chen, Jinhui; Xie, Jianbo; Chen, Beibei; Quan, Mingyang; Li, Ying; Li, Bailian; Zhang, Deqiang

    2016-10-01

    Variation in regulatory factors, including microRNAs (miRNAs), contributes to variation in quantitative and complex traits. However, in plants, variants in miRNAs and their target genes that contribute to natural phenotypic variation, and the underlying regulatory networks, remain poorly characterized. We investigated the associations and interactions of single-nucleotide polymorphisms (SNPs) in miRNAs and their target genes with phenotypes in 435 individuals from a natural population of Populus. We used RNA-seq to identify 217 miRNAs differentially expressed in a tension wood system, and identified 1196 candidate target genes; degradome sequencing confirmed 60 of the target sites. In addition, 72 miRNA-target pairs showed significant co-expression. Gene ontology (GO) term analysis showed that most of the genes in the co-regulated pairs participate in biological regulation. Genome resequencing found 5383 common SNPs (frequency ≥ 0.05) in 139 miRNAs and 31 037 SNPs in 819 target genes. Single-SNP association analyses identified 232 significant associations between wood traits (P ≤ 0.05) and SNPs in 102 miRNAs and 1387 associations with 478 target genes. Among these, 102 miRNA-target pairs associated with the same traits. Multi-SNP associations found 102 epistatic pairs associated with traits. Furthermore, a reconstructed regulatory network contained 12 significantly co-expressed pairs, including eight miRNAs and nine targets associated with traits. Lastly, both expression and genetic association showed that miR156i, miR156j, miR396a and miR6445b were involved in the formation of tension wood. This study shows that variants in miRNAs and target genes contribute to natural phenotypic variation and annotated roles and interactions of miRNAs and their target genes by genetic association analysis. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  14. Males exhibit competitive advantages over females of Populus deltoides under salinity stress.

    Science.gov (United States)

    Li, Yan; Duan, Baoli; Chen, Juan; Korpelainen, Helena; Niinemets, Ülo; Li, Chunyang

    2016-12-01

    Sexual competition among dioecious plants affects sex ratios and the spatial distribution of the sexes in different environments. At present, little is known about sexual dimorphisms induced by different competition patterns under salinity stress. We employed Populus deltoides as a model to investigate sex-related growth as well as physiological and biochemical responses to salinity stress under conditions of intrasexual and intersexual competition. Potted seedlings (two seedlings per pot; two females, two males, or one female and one male) were exposed to two salt levels (0 and 50 mM NaCl) and salinity- and competition-driven differences in growth, assimilation rate, water use, contents of leaf pigments and osmotica, hydrogen peroxide (H2O2), and antioxidant enzyme and nitrate reductase activity were examined. In the absence of salinity, no significant differences in competitive ability between males and females subjected to intrasexual competition were observed, although the growth of females was moderately greater under intersexual competition. The salinity treatment significantly increased the sex differences in competitive ability, especially under intersexual competition. Under salinity stress, males showed decreased height, but displayed greater capacity for osmotic adjustment, enhancement of long-term water-use efficiency and increase in antioxidant enzyme activities. The absolute values of these traits were greater in salt-stressed males than in females under intersexual competition. In addition, salt-stressed males accumulated less Cl(-) and had lower H2O2 contents than females. These data collectively demonstrate that the competitive advantage of females in non-stressed conditions is lost under salinity. Greater salinity resistance of males growing intermixed with females under salt stress can importantly affect the sex ratio of P. deltoides populations. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions

  15. Sex-specific responses of Populus deltoides to Glomus intraradices colonization and Cd pollution.

    Science.gov (United States)

    Chen, Lianghua; Zhang, Danju; Yang, Wanqin; Liu, Yang; Zhang, Li; Gao, Shun

    2016-07-01

    The positive effects of arbuscular mycorrhizal fungi (AM) on the survival, growth and physiology of plants under various stress conditions have been widely recognized. However, whether sex-dependent susceptibility to AM colonization exists, which can induce a differential tolerance between the sexes to stress conditions, is still unclear. In this study, we investigated the effects of Glomus intraradices on Cd-stressed males and females of Populus deltoides (spiked with 10 mg Cd per kg dry substrate) in terms of morphology, physiology, biochemistry, ultrastructure, and toxin storage and translocation. Exposure to Cd promoted the colonization by G. intraradices in males, but not in females. Generally, females suffered more impairments than males in response to Cd stress, reflected by leaf symptoms, the extent of lipid peroxidation, and integrity of the cellular ultrastructure, whether they were inoculated or not. Inoculation with G. intraradices alleviated the phytotoxic effects of Cd in females by stimulating antioxidant enzymes, decreasing levels of reactive oxygen species (ROS) and restricting Cd transfer to the shoots. In contrast, these beneficial effects induced by AM were not detected in mycorrhizal males compared to non-mycorrhizal males, based on thiobarbituric acid-reactive substances (TBARS) and cellular ultrastructure. Inoculation with AM promoted Cd accumulation in males but not in females, and caused the sequestration of more toxic Cd in the root systems in both sexes. Therefore, our results suggest that inoculated males of P. deltoides are suitable candidates for phytostabilization in Cd-polluted soils, due to their higher accumulation ability and greater tolerance relative to inoculated females.

  16. Organ and Tissue-specific Sucrose Transporters. Important Hubs in Gene and Metabolite Networks Regulating Carbon Use in Wood-forming Tissues of Populus

    Energy Technology Data Exchange (ETDEWEB)

    Harding, Scott A. [Univ. of Georgia, Athens, GA (United States); Tsai, Chung-Jui [Univ. of Georgia, Athens, GA (United States)

    2016-01-04

    The overall project objective was to probe the relationship between sucrose transporters and plant productivity in the biomass for biofuels woody perennial, Populus. At the time the proposal was written, sucrose transporters had already been investigated in many plant model systems, primarily with respect to the export of photosynthate sucrose from source leaves, and the uptake of sucrose in storage organs and seeds. Preliminary findings by the PI found that in Populus, sucrose transporter genes (SUTs) were well expressed in wood-forming tissues that comprise the feedstock for biofuels production. Because sucrose comprises by far the predominant form in which photosynthate is delivered from source organs to sink organs like roots and wood-forming tissues, SUTs control a gate that nominally at least could impact the allocation or partitioning of sucrose for potentially competing end uses like growth (stem biomass) and storage. In addition, water use might be conditioned by the way in which sucrose is distributed throughout the plant, and/or by the way in which sucrose is partitioned intracellularly. Several dozen transgenic lines were produced in year 1 of the project to perturb the expression ratio of multiple plasma membrane (PM) SUTs (intercellular trafficking), versus the single tonoplast membrane (TM) sucrose transporter that effectively regulates intracellular trafficking of sucrose. It was possible to obtain transgenic lines with dual SUT gene knockdown using the 35S promoter, but not the wood-specific TUA1 promoter. By the end of project year 2, a decision was made to work with the 35S plants while archiving the TUA1 plants. The PhD candidate charged with producing the transgenic lines abandoned the project during its second year, substantially contributing to the decision to operate with just the 35S lines. That student’s interests ranged more toward evolutionary topics, and a report on SUT gene evolution was published (Peng et al 2014).

  17. Lead uptake increases drought tolerance of wild type and transgenic poplar (Populus tremula x P. alba) overexpressing gsh 1.

    Science.gov (United States)

    Samuilov, Sladjana; Lang, Friedericke; Djukic, Matilda; Djunisijevic-Bojovic, Danijela; Rennenberg, Heinz

    2016-09-01

    Growth and development of plants largely depends on their adaptation ability in a changing climate. This is particularly true on heavy metal contaminated soils, but the interaction of heavy metal stress and climate on plant performance has not been intensively investigated. The aim of the present study was to elucidate if transgenic poplars (Populus tremula x P. alba) with enhanced glutathione content possess an enhanced tolerance to drought and lead (Pb) exposure (single and in combination) and if they are good candidates for phytoremediation of Pb contaminated soil. Lead exposure reduced growth and biomass accumulation only in above-ground tissue of wild type poplar, although most of lead accumulated in the roots. Drought caused a decline of the water content rather than reduced biomass production, while Pb counteracted this decline in the combined exposure. Apparently, metals such as Pb possess a protective function against drought, because they interact with abscisic acid dependent stomatal closure. Lead exposure decreased while drought increased glutathione content in leaves of both plant types. Lead accumulation was higher in the roots of transgenic plants, presumably as a result of chelation by glutathione. Water deprivation enhanced Pb accumulation in the roots, but Pb was subject to leakage out of the roots after re-watering. Transgenic plants showed better adaptation under mild drought plus Pb exposure partially due to improved glutathione synthesis. However, the transgenic plants cannot be considered as a good candidate for phytoremediation of Pb, due to its small translocation to the shoots and its leakage out of the roots upon re-watering.

  18. Tissue Culture Technology for Populus × euramericana Hybrids: Effect of Genotype on in Vitro Regeneration

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to select a suitable genotype for the studies on genetic transformation, the difference among three genotypes (DN04-18, DN04-25 and DN04-26) of Populus × euramericana (Populus deltoides × P. nigra) in terms of shoot regeneration was investigated in this paper. An efficient in vitro micropropagation method was successfully established for genotype DN04-18. The high frequency shoot regeneration (90.0%) from leaf discs was obtained in genotype DN04-18 on the modified Murashige and Skoog (mMS) medium w...

  19. Structural characterization of lignin from triploid of Populus tomentosa Carr.

    Science.gov (United States)

    Yuan, Tong-Qi; Sun, Shao-Ni; Xu, Feng; Sun, Run-Cang

    2011-06-22

    To improve yields while minimizing the extent of mechanical action (just 2 h of planetary ball-milling), the residual wood meal obtained from extraction of milled wood lignin (MWL) was sequentially treated with cellulolytic enzyme and alkali, and the yields of MWL, cellulolytic enzyme lignin (CEL), and alkaline lignin (AL) were 5.4, 23.2, and 16.3%, respectively. The chemical structures of the lignin fractions obtained were characterized by carbohydrate analysis, gel permeation chromatography (GPC), Fourier transform infrared (FT-IR) spectroscopy, and various advanced NMR spectroscopic techniques. The results showed that the lignin isolated as MWL during the early part of ball milling may originate mainly from the middle lamella. This lignin fraction was less degradable and contained more linear hemicelluloses and more C═O in unconjugated groups as well as more phenolic OH groups. Both 1D and 2D NMR spectra analyses confirmed that the lignin in triploid of Populus tomentosa Carr. is GSH-type and partially acylated at the γ-carbon of the side chain. Two-dimensional heteronuclear single-quantum coherence (¹³C-¹H) NMR of MWL, CEL, and AL showed a predominance of β-O-4' aryl ether linkages (81.1-84.5% of total side chains), followed by β-β' resinol-type linkages (12.2-16.4%), and lower amounts of β-5' phenylcoumaran (2.1-2.6%) and β-1' spirodienone-type (0.4-1.4%) linkages. The syringyl (S)/guaiacyl (G) ratios were estimated to be 1.43, 2.29, and 2.83 for MWL, CEL, and AL, respectively.

  20. CHANGES OF CUTICLE SURFACE LIPIDS OF POPULUS ITALICA AND BETULA PENDULA CAUSED BY POLLUTION

    Directory of Open Access Journals (Sweden)

    Zubrovskaya O. M.

    2014-08-01

    Full Text Available Arboreal plants intensively accumulate heavy metals, resulting in a corresponding revocation level of physiological processes. The lipid components operate an important role in the formation of plant resistance. Therefore, it was very important to determine the characteristics of lipid peroxidation flow in leaves of arboreal plants, and changes in the composition of cuticle surface lipids at different levels of heavy metal accumulation. Research objects were Populus italica (Du Roi Moench and Betula pendula Roth. of second age group, growing on the industrial site РJSC ‘Kryvyi Rig Factory of minium’ (with strong contamination and in the arboretum of Kryvyi Rig Botanic Garden, National Academy of Science of Ukraine (conventional control. Leaves were taken from the middle of the crown southwest exposure in phase of leaf full separation and 5-10 day of phase finishing point of their growth. It was shown that P. italica maximally accumulated zinc, content of which was increased in the phase of leaf full separation and on 5-10 day of phase of leaf growth finishing point relative to the control to 12,6 and 23 times respectively. The accumulation level of heavy metals was typically less significant for assimilation organs of B. pendula compared to P. italica. Thus, the content of zinc and lead in the leaves during the study increased only in 2 times towards control. The leaves of B. pendula, unlike P. italica, more intensively accumulated cadmium in the phase of leaf full separation and on 5-10 day of phase finishing point of their growth (it was 6 and 15 times higher relative to control respectively. It was obviously connected to the fact that the surface texture of poplar leaves may cause intense sticking of dust particles containing heavy metals and penetration into the leaves. The effect of heavy metals in both phases of leaf morphogenesis caused an increase in lipid peroxidation by 40-52% for P. italica and almost by 3 times for B. pendula

  1. Constitutive Expression of Sense & Antisense PtAP3, an AP3 Homologue Gene of Populus tomentosa, Affects Growth and Flowering Time in Transgenic Tobacco

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    To analyze the function of PtAP3, an APETALA3 (AP3) homologue gene isolated from Populus tomentosa Carr., the full length sequence (1 797 bp) and a fragment (870 bp) of PtAP3 were fused to a CaMV 35S promoter of pBI121 to generate the sense and antisense constructs of PtAP3. These constructs were transformed into tobacco by Agrobacterium infection of leaf disks and selection on kanamycin medium. Some sense and antisense transgenic tobacco plants were obtained by PCR and Southern blot analysis. Great phenotypic differences in transgenic tobacco plants were observed. Almost all of sense PtAP3 to transgenic tobaccos showed a higher growth rate than those of antisense transformants and a few developed pregnancy earlier than wild type seedlings and antisense transformants under the same conditions.

  2. Efeito da aplicação de calcário em estacas de Populus deltoides Bartr. ex Marsh cultivadas em vaso

    Directory of Open Access Journals (Sweden)

    Jean Gabriel Medeiros da Silva

    2002-01-01

    Full Text Available This work intended to study the behavior of Populus deltoides regarding its development when submitted to different doses of lime. The research was carried out in the Silviculture Tecnology Center, at Universidade Federal de Santa Maria, Santa Maria - RS. The experiment was constituted by forty eight (48 experimental units completely randomized, with six (06 treatments and eight repetitions (08. Each experimental unit was constituted by a vase of three liters containing only one shoot cutting of Populus deltoides. The treatments were constituted by five different doses (T2: 7 tons of lime/ha; T3: 14 tons of lime/ha; T4: 21 tons of lime/ha; T5: 29 tons of lime/ha; T6: 38 tons of lime/ha plus the testimony, determined with base in the soil analysis used in the experiment. The plants were evaluated, after 120 days of the plantation date, considering its growth in height, its diameter of the neck and its weigh dry of the aerial part. The best average were reached by the treatments without lime and with seven tons of lime for ha in all the parameters observed. The other treatments presented inferior averages, which do not possess significant difference to each other at the level of 5%, for all the observed parameters.

  3. Cloning and RNAi Construction of a LEAFY Homologous Gene from Populus tomentosa and Preliminary Study in Tobacco

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    PtLFY, a LEAFY (LFY) gene, was cloned from Populus tomentosa (LM50) by PCR. Sequencing analysis indicated that PtLFY was 2 629 bp long, composed of three exons and two introns and encoded 378 amino acids. The splice donor sites and the splice acceptor sites were in identical positions to the LFY and its homologues. The amino acid sequence inferred was 68%-99% homologous to those of LFY and its homologues by blast analysis in GenBank. The Southern blot analysis indicated that there was a single copy of the PtLFY gene in genomic DNA of male and female P. tomentosa (LM50 and 5082). The pBI121-Ptalfy (reverse)-intron-Ptlfy-GUS-nos was constructed using RNA interference (RNAi) technique and verified by PCR and digestion identification and transformed into tobacco. Some transgenic tobacco plants were obtained by PCR and PCR-Southern identification. The growth was generally repressed in transgenic tobacco plants compared with wild-type ones and some phenotypic differences were observed.

  4. Identification of novel and conserved Populus tomentosa microRNA as components of a response to water stress.

    Science.gov (United States)

    Ren, Yuanyuan; Chen, Lei; Zhang, Yiyun; Kang, Xiangyang; Zhang, Zhiyi; Wang, Yanwei

    2012-06-01

    MicroRNAs (miRNAs) are a class of small, non-coding RNAs that play important downregulation roles in plants growth, development, and stress responses. To better identify Populus tomentosa miRNAs and understand the functions of miRNAs in response to water stress (drought and flooding), 152 conserved miRNAs belonging to 36 miRNA families, 8 known but non-conserved miRNAs and 64 candidate novel miRNAs belonging to 54 miRNA families were identified and analyzed from three small RNA (sRNA) libraries (drought treatment, flooding treatment, and control) by high-throughput sequencing combined with qRT-PCR. Significant changes in the expression of 17 conserved miRNA families and nine novel miRNAs were observed in response to drought stress, and in seven conserved miRNA families and five novel miRNAs in response to flooding stress. Both miRNA and miRNA*s were involved in the regulation of plant stress responses. The annotation of the potential targets of miRNAs with differential expression indicate that many types of genes encoding transcription factors, enzymes, and signal transduction components are implicated in the abiotic stress response..

  5. Genome-wide association study reveals putative regulators of bioenergy traits in Populus deltoides

    Energy Technology Data Exchange (ETDEWEB)

    Fahrenkrog, Annette M. [School of Forest Resources and Conservation, University of Florida, PO Box 110410 Gainesville FL 32611 USA; Plant Molecular and Cellular Biology Graduate Program, University of Florida, PO Box 110690 Gainesville FL 32610 USA; Neves, Leandro G. [School of Forest Resources and Conservation, University of Florida, PO Box 110410 Gainesville FL 32611 USA; Plant Molecular and Cellular Biology Graduate Program, University of Florida, PO Box 110690 Gainesville FL 32610 USA; Resende, Márcio F. R. [School of Forest Resources and Conservation, University of Florida, PO Box 110410 Gainesville FL 32611 USA; Genetics and Genomics Graduate Program, University of Florida, PO Box 103610 Gainesville FL 32610 USA; Vazquez, Ana I. [Department of Epidemiology and Biostatistics, Michigan State University, 909 Fee Road East Lansing MI 48824 USA; de los Campos, Gustavo [Department of Epidemiology and Biostatistics, Michigan State University, 909 Fee Road East Lansing MI 48824 USA; Statistics Department, Michigan State University, 619 Red Cedar Road MI 48824 USA; Dervinis, Christopher [School of Forest Resources and Conservation, University of Florida, PO Box 110410 Gainesville FL 32611 USA; Sykes, Robert [National Renewable Energy Laboratory, 15013 Denver West Parkway Golden CO 80401 USA; Davis, Mark [National Renewable Energy Laboratory, 15013 Denver West Parkway Golden CO 80401 USA; Davenport, Ruth [Biology Department, University of Florida, PO Box 118525 Gainesville FL 32611 USA; Barbazuk, William B. [Plant Molecular and Cellular Biology Graduate Program, University of Florida, PO Box 110690 Gainesville FL 32610 USA; Biology Department, University of Florida, PO Box 118525 Gainesville FL 32611 USA; University of Florida Genetics Institute, University of Florida, PO Box 103610 Gainesville FL 32611 USA; Kirst, Matias [School of Forest Resources and Conservation, University of Florida, PO Box 110410 Gainesville FL 32611 USA; Plant Molecular and Cellular Biology Graduate Program, University of Florida, PO Box 110690 Gainesville FL 32610 USA; University of Florida Genetics Institute, University of Florida, PO Box 103610 Gainesville FL 32611 USA

    2016-09-06

    Genome-wide association studies (GWAS) have been used extensively to dissect the genetic regulation of complex traits in plants. These studies have focused largely on the analysis of common genetic variants despite the abundance of rare polymorphisms in several species, and their potential role in trait variation. Here, we conducted the first GWAS in Populus deltoides, a genetically diverse keystone forest species in North America and an important short rotation woody crop for the bioenergy industry. We searched for associations between eight growth and wood composition traits, and common and low-frequency single-nucleotide polymorphisms detected by targeted resequencing of 18 153 genes in a population of 391 unrelated individuals. To increase power to detect associations with low-frequency variants, multiple-marker association tests were used in combination with single-marker association tests. Significant associations were discovered for all phenotypes and are indicative that low-frequency polymorphisms contribute to phenotypic variance of several bioenergy traits. Our results suggest that both common and low-frequency variants need to be considered for a comprehensive understanding of the genetic regulation of complex traits, particularly in species that carry large numbers of rare polymorphisms. These polymorphisms may be critical for the development of specialized plant feedstocks for bioenergy.

  6. Determination of As in tree-rings of poplar (Populus alba L.) by U-shaped DC arc.

    Science.gov (United States)

    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.

  7. Litter Quality of Populus Species as Affected by Free-Air CO2

    NARCIS (Netherlands)

    Vermue, E.; Buurman, P.; Hoosbeek, M.R.

    2009-01-01

    The effect of elevated CO2 and nitrogen fertilization on the molecular chemistry of litter of three Populus species and associated soil organic matter (SOM) was investigated by pyrolysis-gas chromatography/mass spectrometry. The results are based on 147 quantified organic compounds in 24 litter samp

  8. The Populus homeobox gene ARBORKNOX2 regulates cell differentiation during secondary growth

    Science.gov (United States)

    Juan Du; Shawn D. Mansfield; Andrew T. Groover

    2009-01-01

    The stem cells of the vascular cambium divide to produce daughter cells, which in turn divide before undergoing differentiation during the radial growth of woody stems. The genetic regulation of these developmental events is poorly understood, however. We report here the cloning and functional characterization of a Populus class-I KNOX...

  9. The response of Populus spp. to cadmium stress: chemical, morphological and proteomics study.

    Science.gov (United States)

    Marmiroli, Marta; Imperiale, Davide; Maestri, Elena; Marmiroli, Nelson

    2013-10-01

    Poplar (Populus) species are seen as candidates for removing heavy metal contamination from polluted soil. A bottom-up multidisciplinary approach was utilized to compare the performances of clones 58-861 and Poli (Populus nigra) and A4A, a Populus nigra × Populus deltoides hybrid to Cd toxicity. Qualitative and quantitative differences in their tolerance to Cd exposure and the uptake, accumulation and translocation of Cd were noted following the hydroponic exposure of rooted cuttings to 20 μM CdSO₄ for either 48 h or 14 d. Cadmium was less toxic for the hybrid clone A4A as compared to Poli and 58-861. Cd uptake and root to shoot translocation were determined by AAS, and its compartmentation was analyzed using SEM/EDX. A comparative proteomic approach was utilized to identify changes in proteins expression according to dose and time of exposure. Toxicity to Cd mainly influenced proteins related to general defense, stress response and carbohydrate metabolism.

  10. Clonal variation in lateral and basal rooting of Populus irrigated with landfill leachate

    Science.gov (United States)

    R.S. Zalesny Jr.; J.A. Zalesny

    2011-01-01

    Successful establishment and productivity of Populus depends upon adventitious rooting from: 1) lateral roots that develop from either preformed or induced primordia and 2) basal roots that differentiate from callus at the base of the cutting in response to wounding. Information is needed for phytotechnologies about the degree to which ...

  11. Genome-wide analysis of the structural genes regulating defense phenylpropanoid metabolism in Populus

    Energy Technology Data Exchange (ETDEWEB)

    Tschaplinski, Timothy J [ORNL; Tsai, Chung-Jui [Michigan Technological University; Harding, Scott A [Michigan Technological University; Lindroth, richard L [University of Wisconsin, Madison; Yuan, Yinan [Michigan Technological University

    2006-01-01

    Salicin-based phenolic glycosides, hydroxycinnamate derivatives and flavonoid-derived condensed tannins comprise up to one-third of Populus leaf dry mass. Genes regulating the abundance and chemical diversity of these substances have not been comprehensively analysed in tree species exhibiting this metabolically demanding level of phenolic metabolism. Here, shikimate-phenylpropanoid pathway genes thought to give rise to these phenolic products were annotated from the Populus genome, their expression assessed by semiquantitative or quantitative reverse transcription polymerase chain reaction (PCR), and metabolic evidence for function presented. Unlike Arabidopsis, Populus leaves accumulate an array of hydroxycinnamoyl-quinate esters, which is consistent with broadened function of the expanded hydroxycinnamoyl-CoA transferase gene family. Greater flavonoid pathway diversity is also represented, and flavonoid gene families are larger. Consistent with expanded pathway function, most of these genes were upregulated during wound-stimulated condensed tannin synthesis in leaves. The suite of Populus genes regulating phenylpropanoid product accumulation should have important application in managing phenolic carbon pools in relation to climate change and global carbon cycling.

  12. Selecting and utilizing Populus and Salix for landfill covers: implications for leachate irrigation

    Science.gov (United States)

    Ronald S., Jr. Zalesny; Edmund O. Bauer

    2007-01-01

    The success of using Populus and Salix for phytoremediation has prompted further use of leachate as a combination of irrigation and fertilization for the trees. A common protocol for such efforts has been to utilize a limited number of readily-available genotypes with decades of deployment in other applications, such as fiber or...

  13. Populus seed fibers as a natural source for production of oil super absorbents.

    Science.gov (United States)

    Likon, Marko; Remškar, Maja; Ducman, Vilma; Švegl, Franc

    2013-01-15

    The genus Populus, which includes poplars, cottonwoods and aspen trees, represents a huge natural source of fibers with exceptional physical properties. In this study, the oil absorption properties of poplar seed hair fibers obtained from Populus nigra italica when tested with high-density motor oil and diesel fuel are reported. Poplar seed hair fibers are hollow hydrophobic microtubes with an external diameter between 3 and 12 μm, an average length of 4±1 mm and average tube wall thickness of 400±100 nm. The solid skeleton of the hollow fibers consists of lignocellulosic material coated by a hydrophobic waxy coating. The exceptional chemical, physical and microstructural properties of poplar seed hair fibers enable super-absorbent behavior with high absorption capacity for heavy motor oil and diesel fuel. The absorption values of 182-211 g heavy oil/g fiber and 55-60 g heavy oil/g fiber for packing densities of 0.005 g/cm(3) and 0.02 g/cm(3), respectively, surpass all known natural absorbents. Thus, poplar seed hair fibers obtained from Populus nigra italica and other trees of the genus Populus are an extremely promising natural source for the production of oil super absorbents.

  14. Expression and molecular evolution of two DREB1 genes in black poplar (Populus nigra).

    Science.gov (United States)

    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

  15. Expression and molecular evolution of two DREB1 genes in black poplar (Populus nigra.

    Directory of Open Access Journals (Sweden)

    Yanguang Chu

    Full Text Available 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

  16. Transcriptome responses to aluminum stress in roots of aspen (Populus tremula

    Directory of Open Access Journals (Sweden)

    Grisel Nadine

    2010-08-01

    Full Text Available Abstract Background Ionic aluminum (mainly Al3+ is rhizotoxic and can be present in acid soils at concentrations high enough to inhibit root growth. Many forest tree species grow naturally in acid soils and often tolerate high concentrations of Al. Previously, we have shown that aspen (Populus tremula releases citrate and oxalate from roots in response to Al exposure. To obtain further insights into the root responses of aspen to Al, we investigated root gene expression at Al conditions that inhibit root growth. Results Treatment of the aspen roots with 500 μM Al induced a strong inhibition of root growth within 6 h of exposure time. The root growth subsequently recovered, reaching growth rates comparable to that of control plants. Changes in gene expression were determined after 6 h, 2 d, and 10 d of Al exposure. Replicated transcriptome analyses using the Affymetrix poplar genome array revealed a total of 175 significantly up-regulated and 69 down-regulated genes, of which 70% could be annotated based on Arabidopsis genome resources. Between 6 h and 2 d, the number of responsive genes strongly decreased from 202 to 26, and then the number of changes remained low. The responses after 6 h were characterized by genes involved in cell wall modification, ion transport, and oxidative stress. Two genes with prolonged induction were closely related to the Arabidopsis Al tolerance genes ALS3 (for Al sensitive 3 and MATE (for multidrug and toxin efflux protein, mediating citrate efflux. Patterns of expression in different plant organs and in response to Al indicated that the two aspen genes are homologs of the Arabidopsis ALS3 and MATE. Conclusion Exposure of aspen roots to Al results in a rapid inhibition of root growth and a large change in root gene expression. The subsequent root growth recovery and the concomitant reduction in the number of responsive genes presumably reflect the success of the roots in activating Al tolerance mechanisms. The

  17. The UDP-glucuronate decarboxylase gene family in Populus: structure, expression, and association genetics.

    Directory of Open Access Journals (Sweden)

    Qingzhang Du

    Full Text Available In woody crop plants, the oligosaccharide components of the cell wall are essential for important traits such as bioenergy content, growth, and structural wood properties. UDP-glucuronate decarboxylase (UXS is a key enzyme in the synthesis of UDP-xylose for the formation of xylans during cell wall biosynthesis. Here, we isolated a multigene family of seven members (PtUXS1-7 encoding UXS from Populus tomentosa, the first investigation of UXSs in a tree species. Analysis of gene structure and phylogeny showed that the PtUXS family could be divided into three groups (PtUXS1/4, PtUXS2/5, and PtUXS3/6/7, consistent with the tissue-specific expression patterns of each PtUXS. We further evaluated the functional consequences of nucleotide polymorphisms in PtUXS1. In total, 243 single-nucleotide polymorphisms (SNPs were identified, with a high frequency of SNPs (1/18 bp and nucleotide diversity (πT = 0.01033, θw = 0.01280. Linkage disequilibrium (LD analysis showed that LD did not extend over the entire gene (r (2<0.1, P<0.001, within 700 bp. SNP- and haplotype-based association analysis showed that nine SNPs (Q <0.10 and 12 haplotypes (P<0.05 were significantly associated with growth and wood property traits in the association population (426 individuals, with 2.70% to 12.37% of the phenotypic variation explained. Four significant single-marker associations (Q <0.10 were validated in a linkage mapping population of 1200 individuals. Also, RNA transcript accumulation varies among genotypic classes of SNP10 was further confirmed in the association population. This is the first comprehensive study of the UXS gene family in woody plants, and lays the foundation for genetic improvements of wood properties and growth in trees using genetic engineering or marker-assisted breeding.

  18. DNA binding by the plant-specific NAC transcription factors in crystal and solution

    DEFF Research Database (Denmark)

    Welner, Ditte Hededam; Lindemose, Søren; Grossmann, J. Günter;

    2012-01-01

    NAC (NAM/ATAF/CUC) plant transcription factors regulate essential processes in development, stress responses and nutrient distribution in important crop and model plants (rice, Populus, Arabidopsis), which makes them highly relevant in the context of crop optimization and bioenergy production. Th...

  19. Transcript profiling of a novel plant meristem, the monocot cambium.

    Science.gov (United States)

    Zinkgraf, Matthew; Gerttula, Suzanne; Groover, Andrew

    2017-06-01

    While monocots lack the ability to produce a vascular cambium or woody growth, some monocot lineages evolved a novel lateral meristem, the monocot cambium, which supports secondary radial growth of stems. In contrast to the vascular cambium found in woody angiosperm and gymnosperm species, the monocot cambium produces secondary vascular bundles, which have an amphivasal organization of tracheids encircling a central strand of phloem. Currently there is no information concerning the molecular genetic basis of the development or evolution of the monocot cambium. Here we report high-quality transcriptomes for monocot cambium and early derivative tissues in two monocot genera, Yucca and Cordyline. Monocot cambium transcript profiles were compared to those of vascular cambia and secondary xylem tissues of two forest tree species, Populus trichocarpa and Eucalyptus grandis. Monocot cambium transcript levels showed that there are extensive overlaps between the regulation of monocot cambia and vascular cambia. Candidate regulatory genes that vary between the monocot and vascular cambia were also identified, and included members of the KANADI and CLE families involved in polarity and cell-cell signaling, respectively. We suggest that the monocot cambium may have evolved in part through reactivation of genetic mechanisms involved in vascular cambium regulation. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  20. NCBI nr-aa BLAST: CBRC-TTRU-01-1060 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-TTRU-01-1060 ref|XP_002331444.1| white-brown-complex ABC transporter family [P...opulus trichocarpa] gb|EEF10653.1| white-brown-complex ABC transporter family [Populus trichocarpa] XP_002331444.1 0.007 25% ...

  1. Nitrogen-controlled intra- and interspecific competition between Populus purdomii and Salix rehderiana drive primary succession in the Gongga Mountain glacier retreat area.

    Science.gov (United States)

    Song, Mengya; Yu, Lei; Jiang, Yonglei; Lei, Yanbao; Korpelainen, Helena; Niinemets, Ülo; Li, Chunyang

    2017-03-03

    In this study, intra- and interspecific competition were investigated in early successional Salix rehderiana Schneider and later-appearing Populus purdomii Rehder under non-fertilized (control) and nitrogen (N)-fertilized conditions in the Hailuogou glacier retreat area. Our aim was to discover whether N is a key factor in plant-plant competition and whether N drives the primary succession process in a glacier retreat area. We analyzed differences in responses to intra- and interspecific competition and N fertilization between P. purdomii and S. rehderiana, including parameters such as biomass accumulation, nutrient absorption, non-structural carbohydrates, photosynthetic capacity, hydrolysable amino acids and leaf ultrastructure. In the control treatments, S. rehderiana individuals subjected to interspecific competition benefited from the presence of P. purdomii plants, as indicated by higher levels of biomass accumulation, photosynthetic capacity, N absorption, amino acid contents and photosynthetic N-use efficiency. However, in the N-fertilized treatments, P. purdomii individuals exposed to interspecific competition benefited from the presence of S. rehderiana plants, as shown by a higher growth rate, enhanced carbon gain capacity, greater amino acid contents, and elevated water-use efficiency, whereas the growth of S. rehderiana was significantly reduced. Our results demonstrate that N plays a pivotal role in determining the asymmetric competition pattern among Salicaceae species during primary succession. We argue that the interactive effects of plant-plant competition and N availability are key mechanisms that drive primary succession in the Gongga Mountain glacier retreat area.

  2. Allelic variation in PtGA20Ox associates with growth and wood properties in Populus spp.

    Directory of Open Access Journals (Sweden)

    Jiaxing Tian

    Full Text Available Populus tomentosa is an economically important tree crop that produces wood for lumber, pulp, paper, and biofuels. Wood quality traits are likely to be strongly affected by the plant hormone gibberellic acid (GA, which regulates growth. GA20Ox encodes one of the major regulatory enzymes of GA biosynthesis and may therefore play a large role in growth and wood quality. Here, linkage disequilibrium (LD studies were used to identify significant associations between single nucleotide polymorphisms (SNPs within PtGA20Ox and growth and wood-quality traits of P. tomentosa. We isolated a full-length GA20Ox cDNA from Populus tomentosa by reverse transcription (RT-PCR; this 1401 bp cDNA clone had an open reading frame of 1158 bp and encoded a protein of 385 amino acids. PtGA20Ox transcripts were maximally expressed in the mature xylem of vascular tissues, suggesting that PtGA20Ox is highly expressed and specifically associated with secondary xylem formation. Resequencing the PtGA20Ox locus of 36 individuals identified 55 SNPs, and the frequency of SNPs was 1/31 bp. The 29 most common SNPs (frequency>0.1 were genotyped in an association population (426 individuals that was also phenotyped for key growth and wood quality traits. LD did not extend over the entire gene (r(2<0.1, within 500 bp, demonstrating that a candidate-gene-based LD approach may the best way to understand the molecular basis underlying quantitative variation in this species. SNP- and haplotype-based association analyses indicated that four SNPs (false discovery rate Q<0.05 and 14 haplotypes (P<0.05 were significantly associated with growth and wood properties. The phenotypic variance explained by each SNP ranged from 3.44% to 14.47%. The SNP markers identified in this study can be applied to breeding programs for the improvement of growth and wood-property traits by marker-assisted selection.

  3. Plant host and soil origin influence fungal and bacterial assemblages in the roots of woody plants.

    Science.gov (United States)

    Bonito, Gregory; Reynolds, Hannah; Robeson, Michael S; Nelson, Jessica; Hodkinson, Brendan P; Tuskan, Gerald; Schadt, Christopher W; Vilgalys, Rytas

    2014-07-01

    Microbial communities in plant roots provide critical links between above- and belowground processes in terrestrial ecosystems. Variation in root communities has been attributed to plant host effects and microbial host preferences, as well as to factors pertaining to soil conditions, microbial biogeography and the presence of viable microbial propagules. To address hypotheses regarding the influence of plant host and soil biogeography on root fungal and bacterial communities, we designed a trap-plant bioassay experiment. Replicate Populus, Quercus and Pinus plants were grown in three soils originating from alternate field sites. Fungal and bacterial community profiles in the root of each replicate were assessed through multiplex 454 amplicon sequencing of four loci (i.e., 16S, SSU, ITS, LSU rDNA). Soil origin had a larger effect on fungal community composition than did host species, but the opposite was true for bacterial communities. Populus hosted the highest diversity of rhizospheric fungi and bacteria. Root communities on Quercus and Pinus were more similar to each other than to Populus. Overall, fungal root symbionts appear to be more constrained by dispersal and biogeography than by host availability.

  4. Genetic structure of Populus hybrid zone along the Irtysh River provides insight into plastid-nuclear incompatibility.

    Science.gov (United States)

    Zeng, Yan-Fei; Zhang, Jian-Guo; Duan, Ai-Guo; Abuduhamiti, Bawerjan

    2016-06-16

    In plants, the maintenance of species integrity despite hybridization has often been explained by the co-adaption of nuclear gene complexes. However, the interaction between plastid and nuclear sub-genomes has been underestimated. Here, we analyzed the genetic structure of a Populus alba and P. tremula hybrid zone along the Irtysh River system in the Altai region, northwest China, using both nuclear microsatellites and plastid DNA sequences. We found high interspecific differentiation, although the hybrid P. × canescens was prevalent. Bayesian inference classified most hybrids into F1, followed by a few back-crosses to P. alba, and fewer F2 hybrids and back-crosses to P. tremula, indicating a few introgressions but preference toward P. alba. When plastid haplotypes in parental species were distinct, P. × canescens carried the haplotypes of both parents, but showed significant linkage between intraspecific haplotype and nuclear genotypes at several microsatellite loci. Selection, rather than migration and assortative mating, might have contributed to such plastid-nuclear disequilibria. By removing later-generated hybrids carrying interspecific combinations of haplotype and nuclear genotypes, plastid-nuclear incompatibility has greatly limited the gene exchange between P. alba and P. tremula via backcrossing with hybrids, demonstrating a significant association between plastid haplotype and the proportion of nuclear admixture.

  5. Identification of microRNAs Involved in Regeneration of the Secondary Vascular System in Populus tomentosa Carr

    Science.gov (United States)

    Tang, Fang; Wei, Hairong; Zhao, Shutang; Wang, Lijuan; Zheng, Huanquan; Lu, Mengzhu

    2016-01-01

    Wood formation is a complex developmental process primarily controlled by a regulatory transcription network. MicroRNAs (miRNAs) can modulate the expression of target genes involved in plant growth and development by inducing mRNA degradation and translational repression. In this study, we used a model of secondary vascular system regeneration established in Populus tomentosa to harvest differentiating xylem tissues over time for high-throughput sequencing of small RNAs. Analysis of the sequencing data identified 209 known and 187 novel miRNAs during this regeneration process. Degradome sequencing analysis was then performed, revealing 157 and 75 genes targeted by 21 known and 30 novel miRNA families, respectively. Gene ontology enrichment of these target genes revealed that the targets of 15 miRNAs were enriched in the auxin signaling pathway, cell differentiation, meristem development, and pattern specification process. The major biological events during regeneration of the secondary vascular system included the sequential stages of vascular cambium initiation, formation, and differentiation stages in sequence. This study provides the basis for further analysis of these miRNAs to gain greater insight into their regulatory roles in wood development in trees. PMID:27303419

  6. Importance of crown architecture for leaf area index of different Populus genotypes in a high-density plantation.

    Science.gov (United States)

    Broeckx, L S; Verlinden, M S; Vangronsveld, J; Ceulemans, R

    2012-10-01

    Crown architecture is an important determinant of biomass production and yield of any bio-energy plantation since it determines leaf area display and hence light interception. Four Populus genotypes-of different species and hybrids and with contrasting productivity and leaf area-were examined in terms of their branch characteristics in relation to crown architecture during the first and second growing seasons after plantation establishment. The trees were planted at high density (8000 ha(-1)) on two different former land use types, cropland and pasture. We documented significant differences in branch architecture among the genotypes and for the first year among the former land use types. Land use effects only affected factors not related to canopy closure and wood production, and decreased after the first growing season. This suggested that both former land use types were equally suited for the establishment success of a poplar bio-energy plantation. Tree height and branch dimensions-branch diameter and branch length-were the most important determinants of wood production and maximum leaf area index. Despite the secondary importance of the number of sylleptic branches, these branches contributed significantly to the total leaf area in three out of the four studied genotypes. This indicated that enhanced syllepsis accelerates leaf area development and hence carbon assimilation, especially in the early stages of a high-density plantation with poplar.

  7. Direct matrix-assisted laser desorption/ionization mass spectrometric imaging of cellulose and hemicellulose in Populus tissue.

    Science.gov (United States)

    Lunsford, Kyle Ann; Peter, Gary F; Yost, Richard A

    2011-09-01

    Imaging applied toward lignocellulosic materials requires high molecular specificity to map specific compounds within intact tissue. Although secondary ionization mass spectrometry (SIMS) and matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) with a single stage of MS have been used to image lignocellulosic biomass, the complexity of the plant tissue requires tandem MS, which limits the interpretation of simple MS. MALDI linear ion trap (LIT) tandem MS offers the high molecular specificity needed for lignocellulosic analyses. MALDI-LIT MS analyses of cellulose and xylan (hemicellulose) standards were performed to determine mass-to-charge ratios and fragmentation pathways for identification of these compounds in intact tissue. The MALDI-LIT-MS images of young Populus wood stem showed even distribution of both cellulose and hemicellulose ions; in contrast, the tandem MS images of cellulose and hemicellulose generated by plotting characteristic fragment ions resulted in drastically different images. This demonstrates that isobaric ions are present during MALDI-LIT-MS analyses of wood tissue and tandem MS is necessary to distinguish between isobaric species for selective imaging of carbohydrates in biomass.

  8. Disentangling herbivore impacts on Populus tremuloides: a comparison of native ungulates and cattle in Canada's Aspen Parkland.

    Science.gov (United States)

    Bork, Edward W; Carlyle, Cameron N; Cahill, James F; Haddow, Rae E; Hudson, Robert J

    2013-11-01

    Ungulates impact woody species' growth and abundance but little is understood about the comparative impacts of different ungulate species on forest expansion in savanna environments. Replacement of native herbivore guilds with livestock [i.e., beef cattle (Bos taurus)] has been hypothesized as a factor facilitating trembling aspen (Populus tremuloides Michx.) encroachment into grasslands of the Northern Great Plains. We used a controlled herbivory study in the Parklands of western Canada to compare the impact of native ungulates and cattle on aspen saplings. Native ungulate treatments included a mixed species guild and sequences of herbivory by different ungulates [bison (Bison bison subsp. bison), elk (Cervus elaphus) then deer (Odocoileus hemionus); or deer, elk, then bison]. Herbivory treatments were replicated in three pastures, within which sets of 40 marked aspen saplings (aspen stand. Stems were assessed for mortality and incremental damage (herbivory, leader breakage, stem abrasion and trampling). Final mortality was greater with exposure to any type of herbivore, but remained similar between ungulate treatments. However, among all treatments, the growth of aspen was highest with exposure only to cattle. Herbivory of aspen was attributed primarily to elk within the native ungulate treatments, with other forms of physical damage, and ultimately sapling mortality, associated with exposure to bison. Overall, these results indicate that native ungulates, specifically elk and bison, have more negative impacts on aspen saplings and provide evidence that native and domestic ungulates can have different functional effects on woody plant dynamics in savanna ecosystems.

  9. Scientific Basis for Sustainable Management of Eucalyptus and Populus as Short-Rotation Woody Crops in the U.S.

    Directory of Open Access Journals (Sweden)

    Eric D. Vance

    2014-05-01

    Full Text Available Short rotation woody crops (SRWC, fast growing tree species that are harvested on short, repeated intervals, can augment traditional fiber sources. These crops have economic and environmental benefits stemming from their capability of supplying fiber on a reduced land base in close proximity to users and when sensitive sites cannot be accessed. Eucalyptus and Populus appear to be genera with the greatest potential to provide supplemental fiber in the U.S. Optimal productivity can be achieved through practices that overcome site limitations and by choosing the most appropriate sites, species, and clones. Some Eucalyptus species are potentially invasive, yet field studies across multiple continents suggest they are slower to disperse than predicted by risk assessments. Some studies have found lower plant and animal diversity in SRWC systems compared to mature, native forests, but greater than some alterative land uses and strongly influenced by stand management, land use history, and landscape context. Eucalyptus established in place of grasslands, arable lands, and, in some cases, native forests can reduce streamflow and lower water tables due to higher interception and transpiration rates but results vary widely, are scale dependent, and are most evident in drier regions.

  10. Identification of microRNAs Involved in Regeneration of the Secondary Vascular System in Populus tomentosa Carr.

    Directory of Open Access Journals (Sweden)

    Fang eTang

    2016-05-01

    Full Text Available Wood formation is a complex developmental process primarily controlled by a regulatory transcription network. MicroRNAs (miRNAs can modulate the expression of target genes involved in plant growth and development by inducing mRNA degradation and translational repression. In this study, we used a model of secondary vascular system regeneration established in Populus tomentosa to harvest differentiating xylem tissues over time for high-throughput sequencing of small RNAs. Analysis of the sequencing data identified 209 known and 187 novel miRNAs during this regeneration process. Degradome sequencing analysis was then performed, revealing 157 and 75 genes targeted by 21 known and 30 novel miRNA families, respectively. Gene ontology enrichment of these target genes revealed that the targets of 15 miRNAs were enriched in the auxin signaling pathway, cell differentiation, meristem development and pattern specification process. The major biological events during regeneration of the secondary vascular system included the sequential stages of vascular cambium initiation, formation, and differentiation stages in sequence. This study provides the basis for further analysis of these miRNAs to gain greater insight into their regulatory roles in wood development in trees.

  11. Effect of nitrate and ammonium fertilization on Zn, Pb, and Cd phytostabilization by Populus euramericana Dorskamp in contaminated technosol.

    Science.gov (United States)

    Qasim, Bashar; Motelica-Heino, Mikael; Bourgerie, Sylvain; Gauthier, Arnaud; Morabito, Domenico

    2015-12-01

    This study aimed at assessing the effect of nitrogen addition under two forms, nitrate and ammonium, on the stabilization of Zn, Pb, and Cd by Populus euramericana Dorskamp grown in contaminated soils for 35 days under controlled conditions. Temporal changes in the soil pore water (SPW) were monitored for pH, dissolved organic carbon (DOC), and total dissolved concentrations of metals in the soils rhizosphere. Rhizospheric SPW pH decreased gradually with NH4(+) addition and increased with NO3(-) addition up to one unit, while it slightly decreased initially then increased for the untreated control soil DOC increased with time up to six times, the highest increase occurring with NH4(+) fertilization. An increase in the metal concentrations in the rhizospheric SPW was observed for NH4(+) addition associated with the lowest rhizospheric SPW pH, whereas the opposite was observed for the control soil and NO3(-) fertilization. Fertilization did not affect plant shoots or roots biomass development compared to the untreated control (without N addition). Metals were mostly accumulated in the rhizosphere and N fertilization increased the accumulation for Zn and Pb while Cd accumulation was enhanced for NH4(+) addition. Collectively, our results suggest metal stabilization by P. euramericana Dorskamp rhizosphere with nitrogen fertilization and are potential for phytostabilization of contaminated technosol.

  12. Effects of Soil Fertility and Atmospheric CO2 Enrichment on Leaf, Stem and Root Dark Respiration of Populus tremuloides

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An open-top chamber experiment was conducted at the University of Michigan Biological Station near Pellston, Michigan, USA, to study the effects of soil fertility and CO2 on leaf, stem and root dark respiration (Rd) of Populus tremuloides. Overall, area-based daytime leaf Rd (Rda) was significantly greater at elevated than at ambient CO2 in high-fertility soil, but not in low-fertility soil. Mass-based leaf Rd (Rdm) was overall greater for high- than for low-fertility soil grown trees at elevated, but not at ambient CO2. Nighttime leaf Rda and Rdm were unaffected by soil fertility or CO2, nor was stem Rda, which ranged from 1.0 to 1.4 μmol m-2 s-1 in the spring and 3.5 to 4.5 μmol m-2 s-1 in the summer. Root Rda was significantly higher in high- than in low-fertility soil, but was unaffected by CO2. Since biomass production of P. tremuloides will be significantly greater at elevated CO2 while specific Rd will either increase or remain unchanged, we predict that carbon loss to the atmosphere through respiration from this ecologically important species would increase at higher CO2. Soil fertility would also interact with elevated CO2 in affecting the carbon flow in the plant-soil-air system.

  13. Effects of Soil Fertility and Atmospheric CO2 Enrichment on Leaf,Stem and Root Dark Respiration of Populus tremuloides

    Institute of Scientific and Technical Information of China (English)

    X.Z.WANG; P.S.CURTIS; 等

    2001-01-01

    An open-top chamber experiment was conducted at the University of Michigan Biological Station near Pellston,Michigan,USA,to study the effects of soil fertility and CO2 on leaf,sdtem and root dark respiration (Rd) of Populus tremuloides.Overall,area-based daytime leaf Rd(Rda) was significantly greater at elevated than at ambient CO2 in high-fertility soil,but not in low-fertility soil.Mass-based leaf Rd(Rdm) was overall greater for high-than for low-fertility soil grown trees at elevated,but not at ambient CO2 .Nighttime leaf Rda and Rdm were unaffected by soil fertility or CO2,nor was stem Rda ,which ranged from 1.0 to 1.4μmol m-2s-1 in the spring and 3.5 to 4.5μmol m-2s-1 in the summer.Root Rda was significantly higher in high-than in low-fertiliy soil,but was unaffected by CO2.Since biomass production of P.tremuloides will be significantly greater at elevated CO2 while specific Rd will either increase or remain unchanged,we predict that carbon loss to the atmosphere through respiration from this ecologically important species would increase at higher CO2.Soil fertility would also interact with elevated CO2 in affecting the carbon flow in the plant-soil-air system.

  14. Sexual epigenetics: gender-specific methylation of a gene in the sex determining region of Populus balsamifera

    Science.gov (United States)

    Bräutigam, Katharina; Soolanayakanahally, Raju; Champigny, Marc; Mansfield, Shawn; Douglas, Carl; Campbell, Malcolm M.; Cronk, Quentin

    2017-01-01

    Methylation has frequently been implicated in gender determination in plants. The recent discovery of the sex determining region (SDR) of balsam poplar, Populus balsamifera, pinpointed 13 genes with differentiated X and Y copies. We tested these genes for differential methylation using whole methylome sequencing of xylem tissue of multiple individuals grown under field conditions in two common gardens. The only SDR gene to show a marked pattern of gender-specific methylation is PbRR9, a member of the two component response regulator (type-A) gene family, involved in cytokinin signalling. It is an ortholog of Arabidopsis genes ARR16 and ARR17. The strongest patterns of differential methylation (mostly male-biased) are found in the putative promoter and the first intron. The 4th intron is strongly methylated in both sexes and the 5th intron is unmethylated in both sexes. Using a statistical learning algorithm we find that it is possible accurately to assign trees to gender using genome-wide methylation patterns alone. The strongest predictor is the region coincident with PbRR9, showing that this gene stands out against all genes in the genome in having the strongest sex-specific methylation pattern. We propose the hypothesis that PbRR9 has a direct, epigenetically mediated, role in poplar sex determination. PMID:28345647

  15. Molecular Cloning and Functional Analysis of UV RESISTANCE LOCUS 8 (PeUVR8 from Populus euphratica.

    Directory of Open Access Journals (Sweden)

    Ke Mao

    Full Text Available Ultraviolet-B (UV-B; 280-315 nm light, which is an integral part of the solar radiation reaching the surface of the Earth, induces a broad range of physiological responses in plants. The UV RESISTANCE LOCUS 8 (UVR8 protein is the first and only light photoreceptor characterized to date that is specific for UV-B light and it regulates various aspects of plant growth and development in response to UV-B light. Despite its involvement in the control of important plant traits, most studies on UV-B photoreceptors have focused on Arabidopsis and no data on UVR8 function are available for forest trees. In this study, we isolated a homologue of the UV receptor UVR8 of Arabidopsis, PeUVR8, from Populus euphratica (Euphrates poplar and analyzed its structure and function in detail. The deduced PeUVR8 amino acid sequence contained nine well-conserved regulator of chromosome condensation 1 (RCC1 repeats and the region 27 amino acids from the C terminus (C27 that interact with COP1 (CONSTITUTIVELY PHOTOMORPHOGENIC1. Secondary and tertiary structure analysis showed that PeUVR8 shares high similarity with the AtUVR8 protein from Arabidopsis thaliana. Using heterologous expression in Arabidopsis, we showed that PeUVR8 overexpression rescued the uvr8 mutant phenotype. In addition, PeUVR8 overexpression in wild-type background seedlings grown under UV-B light inhibited hypocotyl elongation and enhanced anthocyanin accumulation. Furthermore, we examined the interaction between PeUVR8 and AtCOP1 using a bimolecular fluorescence complementation (BiFC assay. Our data provide evidence that PeUVR8 plays important roles in the control of photomorphogenesis in planta.

  16. A multifactor analysis of fungal and bacterial community structure in the root microbiome of mature Populus deltoides trees.

    Science.gov (United States)

    Shakya, Migun; Gottel, Neil; Castro, Hector; Yang, Zamin K; Gunter, Lee; Labbé, Jessy; Muchero, Wellington; Bonito, Gregory; Vilgalys, Rytas; Tuskan, Gerald; Podar, Mircea; Schadt, Christopher W

    2013-01-01

    Bacterial and fungal communities associated with plant roots are central to the host health, survival and growth. However, a robust understanding of the root-microbiome and the factors that drive host associated microbial community structure have remained elusive, especially in mature perennial plants from natural settings. Here, we investigated relationships of bacterial and fungal communities in the rhizosphere and root endosphere of the riparian tree species Populus deltoides, and the influence of soil parameters, environmental properties (host phenotype and aboveground environmental settings), host plant genotype (Simple Sequence Repeat (SSR) markers), season (Spring vs. Fall) and geographic setting (at scales from regional watersheds to local riparian zones) on microbial community structure. Each of the trees sampled displayed unique aspects to its associated community structure with high numbers of Operational Taxonomic Units (OTUs) specific to an individual trees (bacteria >90%, fungi >60%). Over the diverse conditions surveyed only a small number of OTUs were common to all samples within rhizosphere (35 bacterial and 4 fungal) and endosphere (1 bacterial and 1 fungal) microbiomes. As expected, Proteobacteria and Ascomycota were dominant in root communities (>50%) while other higher-level phylogenetic groups (Chytridiomycota, Acidobacteria) displayed greatly reduced abundance in endosphere compared to the rhizosphere. Variance partitioning partially explained differences in microbiome composition between all sampled roots on the basis of seasonal and soil properties (4% to 23%). While most variation remains unattributed, we observed significant differences in the microbiota between watersheds (Tennessee vs. North Carolina) and seasons (Spring vs. Fall). SSR markers clearly delineated two host populations associated with the samples taken in TN vs. NC, but overall host genotypic distances did not have a significant effect on corresponding communities that

  17. Prevalence of LuxR- and LuxI-type quorum sensing circuits in members of the Populus deltoides microbiome

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Amy L [University of Washington, Seattle; Lappala, Colin [University of Washington, Seattle; Morlen, Ryan [University of Washington, Seattle; Pelletier, Dale A [ORNL; Lu, Tse-Yuan [ORNL; Lankford, Patricia K [ORNL; Harwood, Caroline S [University of Washington, Seattle; Greenberg, E. Peter [University of Washington, Seattle

    2013-01-01

    We are interested in the root microbiome of the fast-growing Eastern cottonwood tree, Populus 25 deltoides. There is a large bank of bacterial isolates from P. deltoides and there are 44 draft 26 genomes of bacterial endophyte and rhizosphere isolates. As a first step in efforts to understand 27 the roles of bacterial communication and plant-bacterial signaling in P. deltoides we focused on 28 the prevalence of acyl-homoserine lactone (AHL) quorum sensing signal production and 29 reception in members of the P. deltoides microbiome. We screened 129 bacterial isolates for 30 AHL production using a broad-spectrum bioassay that responds to many but not all AHLs, and 31 we queried the available genome sequences of microbiome isolates for homologs of AHL 32 synthase and receptor genes. AHL signal production was detected in 40% of 129 strains tested. 33 Positive isolates included -, - and -Proteobacteria. Members of the luxI family of AHL 34 synthases were identified in 18 of 39 Proteobacteria genomes including genomes of some 35 isolates that tested negative in the bioassay. Members of the luxR family of transcription factors, 36 that include AHL-responsive factors, were more abundant than luxI homologs. There were 72 in 37 the 39 Proteobacteria genomes. Some of the luxR homologs appear to be members of a 38 subfamily of LuxRs that respond to as yet unknown plant signals rather than bacterial AHLs. 39 Apparently, there is a substantial capacity for AHL cell-to-cell communication in Proteobacteria 40 of the P. deltoides microbiota and there are also Proteobacteria with LuxR homologs of the type 41 hypothesized to respond to plant signals or cues.

  18. A multifactor analysis of fungal and bacterial community structure in the root microbiome of mature Populus deltoides trees.

    Directory of Open Access Journals (Sweden)

    Migun Shakya

    Full Text Available Bacterial and fungal communities associated with plant roots are central to the host health, survival and growth. However, a robust understanding of the root-microbiome and the factors that drive host associated microbial community structure have remained elusive, especially in mature perennial plants from natural settings. Here, we investigated relationships of bacterial and fungal communities in the rhizosphere and root endosphere of the riparian tree species Populus deltoides, and the influence of soil parameters, environmental properties (host phenotype and aboveground environmental settings, host plant genotype (Simple Sequence Repeat (SSR markers, season (Spring vs. Fall and geographic setting (at scales from regional watersheds to local riparian zones on microbial community structure. Each of the trees sampled displayed unique aspects to its associated community structure with high numbers of Operational Taxonomic Units (OTUs specific to an individual trees (bacteria >90%, fungi >60%. Over the diverse conditions surveyed only a small number of OTUs were common to all samples within rhizosphere (35 bacterial and 4 fungal and endosphere (1 bacterial and 1 fungal microbiomes. As expected, Proteobacteria and Ascomycota were dominant in root communities (>50% while other higher-level phylogenetic groups (Chytridiomycota, Acidobacteria displayed greatly reduced abundance in endosphere compared to the rhizosphere. Variance partitioning partially explained differences in microbiome composition between all sampled roots on the basis of seasonal and soil properties (4% to 23%. While most variation remains unattributed, we observed significant differences in the microbiota between watersheds (Tennessee vs. North Carolina and seasons (Spring vs. Fall. SSR markers clearly delineated two host populations associated with the samples taken in TN vs. NC, but overall host genotypic distances did not have a significant effect on corresponding communities

  19. A multifactor analysis of fungal and bacterial community structure of the root microbiome of mature Populus deltoides trees

    Energy Technology Data Exchange (ETDEWEB)

    Shakya, Migun [ORNL; Gottel, Neil R [ORNL; Castro Gonzalez, Hector F [ORNL; Yang, Zamin [ORNL; Gunter, Lee E [ORNL; Labbe, Jessy L [ORNL; Muchero, Wellington [ORNL; Bonito, Gregory [Duke University; Vilgalys, Rytas [Duke University; Tuskan, Gerald A [ORNL; Podar, Mircea [ORNL; Schadt, Christopher Warren [ORNL

    2013-01-01

    Bacterial and fungal communities associated with plant roots are central to the host- health, survival and growth. However, a robust understanding of root-microbiome and the factors that drive host associated microbial community structure have remained elusive, especially in mature perennial plants from natural settings. Here, we investigated relationships of bacterial and fungal communities in the rhizosphere and root endosphere of the riparian tree species Populus deltoides, and the influence of soil parameters, environmental properties (host phenotype and aboveground environmental settings), host plant genotype (Simple Sequence Repeat (SSR) markers), season (Spring vs. Fall) and geographic setting (at scales from regional watersheds to local riparian zones) on microbial community structure. Each of the trees sampled displayed unique aspects to it s associated community structure with high numbers of Operational Taxonomic Units (OTUs) specific to an individual trees (bacteria >90%, fungi >60%). Over the diverse conditions surveyed only a small number of OTUs were common to all samples within rhizosphere (35 bacterial and 4 fungal) and endosphere (1 bacterial and 1 fungal) microbiomes. As expected, Proteobacteria and Ascomycota were dominant in root communities (>50%) while other higher-level phylogenetic groups (Chytridiomycota, Acidobacteria) displayed greatly reduced abundance in endosphere compared to the rhizosphere. Variance partitioning partially explained differences in microbiome composition between all sampled roots on the basis of seasonal and soil properties (4% to 23%). While most variation remains unattributed, we observed significant differences in the microbiota between watersheds (Tennessee vs. North Carolina) and seasons (Spring vs. Fall). SSR markers clearly delineated two host populations associated with the samples taken in TN vs. NC, but overall genotypic distances did not have a significant effect on corresponding communities that could be

  20. 美洲黑杨材性相关候选基因PdCYTOB的功能鉴定%Functional Identification of Wood-property Candidate Gene PdCYTOB in Populus deltoides

    Institute of Scientific and Technical Information of China (English)

    李少锋; 苏晓华; 张冰玉; 黄秦军; 褚延广; 丁昌俊

    2011-01-01

    We used quantitative real-time RT-PCR to investigate the tissue expression patterns of cytokinin binding-protein PdCYTOB, which is related to the wood properties of Populus deltoides. PdCYTOB was expressed predominantly in immature xylem, immature phloem and the phloem zone of the stem of P. Deltoides. Southern blot and RT-PCR were used to detect antisense PdCYTOS-transgenic Populus davidiana x P. Bolleana plants. The antisense PdCYTOB gene was integrated into the genome of the poplar and expressed. Phenotype, anatomical studies and microfibrillar angle analysis revealed the plant height of transgenic poplar higher than that of untransformed lines, as well as xylem and the phloem zone of plants with antisense PdCYTOB wider than those of untransformed lines. In addition, the microfibrillar angle of transgenic plants was decreased in the test field. Thus, pulping and papermaking properties might be improved in antisense-PdCYTOB transformed lines. Our study sheds light on the molecular mechanism of PdCYTOB in wood formation in P. Deltoides.%利用RT-PCR技术研究了美洲黑杨(Populus deltoides)材性相关候选基因细胞分裂素结合蛋白(cytokinin binding protein)基因PdCYTOB的表达谱,结果显示,在未成熟木质部、未成熟韧皮部和韧皮部中PdCTOB基因具有较高水平的表达量.对导入反义PdCYTOB的山新杨(Populus davidiana x P.bolleana)植株进行Southern杂交和RT-PCR检测,证实反义PdCYTOB基因已整合到杨树基因组中并表达.对大田转基因株系及对照植株进行表型观察、组织切片和微纤丝角的测定,结果表明,转反义PdCYTOB基因植株的高度明显增加,木质部、韧皮部变宽,微纤丝角明显变小,初步表明转基因杨树在造纸性能上有所改良.这些研究结果对于阐明PdCYTOB在美洲黑杨木材形成中的分子作用机制具有重要的理论意义.

  1. Exotic woody plant invaders of the Transvaal

    OpenAIRE

    Henderson, L.; K. J. Musil

    1984-01-01

    The frequency and abundance o ;f exotic, woody plant invaders were recorded in 60% of the quarter degree squares in the study area. Sixty-one invaders were encountered o f which the most important and aggressive were Acacia dealbaia, Populus spp.,  Melia azedarach, Opuntia ficus-indica, Salix babylonica and  Acacia mearnsii. Invasion patterns are discussed and an attempt is made to correlate distribution with environmental factors. Attention is drawn to the areas of greatest invasion and the ...

  2. NON DESTRUCTIVE EVALUATION OF HEARTWOOD DIAMETER AT BREAST HEIGHT FOR EUCALYPTUS GLOBULUS AND POPULUS EURAMERICANA HYBRID

    Directory of Open Access Journals (Sweden)

    Hugo Alexandre Jóia

    2006-12-01

    Full Text Available The objective of this study was the evaluation of the heartwood diameter (dcerne at breast height on stand trees, for Eucalyptus globulus Labill and the hybrid Populus euramericana. The data used was collected in eucalyptus and popular pure plantations in Central and North Portugal.The non destructive methods tested in the evaluation of heartwood diameter at breast height were [1] visual identification of the heartwood on core samples and [2] indirect estimation using mathematic models. The results allow to consider that visual determination of dcerne is appropriate for Populus, and development of prediction models based diameter at breast height (d, total height (h and age (t, give better results for eucalyptus.

  3. Cadmium phytoextraction potential of poplar clones (Populus spp.)

    Energy Technology Data Exchange (ETDEWEB)

    Pilipovic, A.; Orlovic, S.; Petrovic, N. [Faculty of Agriculture, Inst. of Lowland Forestry and Environment, Novi Sad (Czechoslovakia); Nikolic, N.; Krstic, B. [Faculty of Natural Sciences, Dept. of Biology and Ecology, Novi Sad (Czechoslovakia)

    2005-04-01

    Biomass production, leaf number and area, photosynthetic and dark respiration rates, leaf concentration of photosynthetic pigments, nitrate reductase activity, as well as cadmium concentrations in leaves, stem, and roots were measured in poplar clones PE 4/68, B-229, 665, and 45/51. Plants were grown hydroponically under controlled conditions and treated with two different cadmium (Cd) concentrations (10{sup -5} and 10{sup -7} M) in the same background solution (Hoagland's solution). The presence of Cd did not cause serious disturbance of growth and physiological parameters in the studied poplar clones. Cd concentrations in plant tissues reflected external concentrations. In treated plants, root contents increased from 38.57 to 511.51 ppm, leaf contents from 0.91 to 7.50, while stem contents ranged from 1.37 to 9.50 ppm. (orig.)

  4. NON DESTRUCTIVE EVALUATION OF HEARTWOOD DIAMETER AT BREAST HEIGHT FOR EUCALYPTUS GLOBULUS AND POPULUS EURAMERICANA HYBRID

    OpenAIRE

    Hugo Alexandre Jóia; Teresa Fonseca; Maria Emília Silva; Carlos Pacheco Marques

    2006-01-01

    The objective of this study was the evaluation of the heartwood diameter (dcerne) at breast height on stand trees, for Eucalyptus globulus Labill and the hybrid Populus euramericana. The data used was collected in eucalyptus and popular pure plantations in Central and North Portugal.The non destructive methods tested in the evaluation of heartwood diameter at breast height were [1] visual identification of the heartwood on core samples and [2] indirect estimation using mathematic models. The...

  5. Successful Agrobacterium-mediated transformation of Populus tomentosa with apple SPDS gene

    Institute of Scientific and Technical Information of China (English)

    LIU Ting-ting; PANG Xiao-ming; LONG Cui; ZHANG Zhi-yi

    2008-01-01

    The problem of salinized soils has become one of the most serious constraints to agricultural and forest productivity. With the purpose of enhancing salt stress tolerance of Populus tomentosa, we transformed this tree species with spermidine synthase (SPDS) genes derived from an apple by an Agrobacterium-mediatod method. Four transgenic clones were confirmed by PCR and Southern blot analysis. As well, the expression of introduced SPDS genes was analyzed by real-time quantitative PCR.

  6. Genotypic Tannin Levels in Populus tremula Impact the Way Nitrogen Enrichment Affects Growth and Allocation Responses for Some Traits and Not for Others.

    Directory of Open Access Journals (Sweden)

    Franziska Bandau

    Full Text Available Plant intraspecific variability has been proposed as a key mechanism by which plants adapt to environmental change. In boreal forests where nitrogen availability is strongly limited, nitrogen addition happens indirectly through atmospheric N deposition and directly through industrial forest fertilization. These anthropogenic inputs of N have numerous environmental consequences, including shifts in plant species composition and reductions in plant species diversity. However, we know less about how genetic differences within plant populations determine how species respond to eutrophication in boreal forests. According to plant defense theories, nitrogen addition will cause plants to shift carbon allocation more towards growth and less to chemical defense, potentially enhancing vulnerability to antagonists. Aspens are keystone species in boreal forests that produce condensed tannins to serve as chemical defense. We conducted an experiment using ten Populus tremula genotypes from the Swedish Aspen Collection that express extreme levels of baseline investment into foliar condensed tannins. We investigated whether investment into growth and phenolic defense compounds in young plants varied in response to two nitrogen addition levels, corresponding to atmospheric N deposition and industrial forest fertilization. Nitrogen addition generally caused growth to increase, and tannin levels to decrease; however, individualistic responses among genotypes were found for height growth, biomass of specific tissues, root:shoot ratios, and tissue lignin and N concentrations. A genotype's baseline ability to produce and store condensed tannins also influenced plant responses to N, although this effect was relatively minor. High-tannin genotypes tended to grow less biomass under low nitrogen levels and more at the highest fertilization level. Thus, the ability in aspen to produce foliar tannins is likely associated with a steeper reaction norm of growth responses

  7. Genotypic Tannin Levels in Populus tremula Impact the Way Nitrogen Enrichment Affects Growth and Allocation Responses for Some Traits and Not for Others.

    Science.gov (United States)

    Bandau, Franziska; Decker, Vicki Huizu Guo; Gundale, Michael J; Albrectsen, Benedicte Riber

    2015-01-01

    Plant intraspecific variability has been proposed as a key mechanism by which plants adapt to environmental change. In boreal forests where nitrogen availability is strongly limited, nitrogen addition happens indirectly through atmospheric N deposition and directly through industrial forest fertilization. These anthropogenic inputs of N have numerous environmental consequences, including shifts in plant species composition and reductions in plant species diversity. However, we know less about how genetic differences within plant populations determine how species respond to eutrophication in boreal forests. According to plant defense theories, nitrogen addition will cause plants to shift carbon allocation more towards growth and less to chemical defense, potentially enhancing vulnerability to antagonists. Aspens are keystone species in boreal forests that produce condensed tannins to serve as chemical defense. We conducted an experiment using ten Populus tremula genotypes from the Swedish Aspen Collection that express extreme levels of baseline investment into foliar condensed tannins. We investigated whether investment into growth and phenolic defense compounds in young plants varied in response to two nitrogen addition levels, corresponding to atmospheric N deposition and industrial forest fertilization. Nitrogen addition generally caused growth to increase, and tannin levels to decrease; however, individualistic responses among genotypes were found for height growth, biomass of specific tissues, root:shoot ratios, and tissue lignin and N concentrations. A genotype's baseline ability to produce and store condensed tannins also influenced plant responses to N, although this effect was relatively minor. High-tannin genotypes tended to grow less biomass under low nitrogen levels and more at the highest fertilization level. Thus, the ability in aspen to produce foliar tannins is likely associated with a steeper reaction norm of growth responses, which suggests a

  8. Genotypic Tannin Levels in Populus tremula Impact the Way Nitrogen Enrichment Affects Growth and Allocation Responses for Some Traits and Not for Others

    Science.gov (United States)

    Bandau, Franziska; Decker, Vicki Huizu Guo; Gundale, Michael J.; Albrectsen, Benedicte Riber

    2015-01-01

    Plant intraspecific variability has been proposed as a key mechanism by which plants adapt to environmental change. In boreal forests where nitrogen availability is strongly limited, nitrogen addition happens indirectly through atmospheric N deposition and directly through industrial forest fertilization. These anthropogenic inputs of N have numerous environmental consequences, including shifts in plant species composition and reductions in plant species diversity. However, we know less about how genetic differences within plant populations determine how species respond to eutrophication in boreal forests. According to plant defense theories, nitrogen addition will cause plants to shift carbon allocation more towards growth and less to chemical defense, potentially enhancing vulnerability to antagonists. Aspens are keystone species in boreal forests that produce condensed tannins to serve as chemical defense. We conducted an experiment using ten Populus tremula genotypes from the Swedish Aspen Collection that express extreme levels of baseline investment into foliar condensed tannins. We investigated whether investment into growth and phenolic defense compounds in young plants varied in response to two nitrogen addition levels, corresponding to atmospheric N deposition and industrial forest fertilization. Nitrogen addition generally caused growth to increase, and tannin levels to decrease; however, individualistic responses among genotypes were found for height growth, biomass of specific tissues, root:shoot ratios, and tissue lignin and N concentrations. A genotype’s baseline ability to produce and store condensed tannins also influenced plant responses to N, although this effect was relatively minor. High-tannin genotypes tended to grow less biomass under low nitrogen levels and more at the highest fertilization level. Thus, the ability in aspen to produce foliar tannins is likely associated with a steeper reaction norm of growth responses, which suggests a

  9. Highly efficient CRISPR/Cas9-mediated targeted mutagenesis of multiple genes in Populus%应用CRISPR/Cas9技术在杨树中高效敲除多个靶基因

    Institute of Scientific and Technical Information of China (English)

    刘婷婷; 范迪; 冉玲玉; 姜渊忠; 刘瑞; 罗克明

    2015-01-01

    The typeⅡCRISPR/Cas9 system (Clustered regularly interspaced short palindromic repeats/CRISPR-associated 9) has been widely used in bacteria, yeast, animals and plants as a targeted genome editing tech-nique. In previous work, we have successfully knocked out the endogenous phytoene dehydrogenase (PDS) gene in Populus tomentosa Carr. using this system. To study the effect of target design on the efficiency of CRISPR/Cas9-mediated gene knockout in Populus, we analyzed the efficiency of mutagenesis using different sin-gle-guide RNA (sgRNA) that target PDS DNA sequence. We found that mismatches between the sgRNA and the tar-get DNA resulted in decreased efficiency of mutagenesis and even failed mutagenesis. Moreover, complementari-ty between the 3′ end nucleotide of sgRNA and target DNA is especially crucial for efficient mutagenesis. Further sequencing analysis showed that two PDS homologs in Populus, PtPDS1 and PtPDS2, could be knocked out simul-taneously using this system with 86.4% and 50% efficiency, respectively. These results indicated the possibility of introducing mutations in two or more endogenous genes efficiently and obtaining multi-mutant strains of Populus using this system. We have indeed generated several knockout mutants of transcription factors and structural genes in Populus, which establishes a foundation for future studies of gene function and genetic improvement of Populus.%CRISPR/Cas9系统是一种广泛应用于细菌、酵母、动物和植物中的基因组定点编辑技术。本课题组在前期工作中利用该系统在毛白杨(Populus tomentosa Carr.)中率先实现了对内源基因—八氢番茄红素脱氢酶(Phytoene dehydrogenase, PDS)基因的定点敲除。为研究靶点的设计和选择对该系统介导的杨树内源基因敲除效率的影响,本文分析了不同单向导RNA(Single-guide RNA, sgRNA)结合毛白杨PDS(PtPDS)靶基因DNA序列后对突变效率的影响。结果发现 sgRNA 与靶基因间的碱

  10. Estimating Stem Volume Using QuickBird Imagery and Allometric Relationships for Open Populus xiaohei Plantations

    Institute of Scientific and Technical Information of China (English)

    Xiao-Qing Wang; Zeng-Yuan Li; Xing-E Liu; Guang Deng; Ze-Hui Jiang

    2007-01-01

    There has been a great deal of interest in studying the crown of trees using remote sensing data. In this study, crown width was extracted from high-resolution QuickBird images for open Populus xiaohei plantations. Regression models for predicting the individual stem volumes of Populus xiaohei were established using extracted crown width, as well as estimated tree parameters (i.e. diameter at breast height [DBH] and tree height) as predictors. Our results indicated that crown width could be accurately extracted from QuickBird images using a multi-scale segmentation approach with a mean relative error of 5.74%, especially for wide-spacing stands. Using either extracted crown width alone or with estimated DBH and tree height can successfully estimate individual stem volume of Populus xiaohei with the R2 value ranging from 0.87 to 0.92 depending on different model forms. In particular, the two second-order polynomial models (model2 and model 6), based on QuickBird image-derived crown widths and estimated DBH and tree heights, respectively, were the best at describing the relationship between stem volume and tree characteristics.

  11. Association genetics and expression patterns of a CBF4 homolog in Populus under abiotic stress.

    Science.gov (United States)

    Li, Ying; Xu, Baohua; Du, Qingzhang; Zhang, Deqiang

    2015-06-01

    New strategies for prevention and treatment of abiotic stress require an improved understanding of stress responses. Here, we examined response differences of a C-repeat binding factor gene (PsCBF4) between five species in the genus Populus. We also used a candidate gene-based approach to identify single nucleotide polymorphisms (SNPs) within PsCBF4 that were associated with physiological and biochemical traits in a natural population (528 unrelated individuals) of Populus simonii. We first isolated a 1,044-bp PsCBF4 cDNA encoding a polypeptide of 256 amino acids. Expression profiling revealed that CBF4 is differentially expressed under cold, heat, drought, and salt conditions among five Populus species. Cold stress is the most significant interspecific difference, and PsCBF4 transcript levels ranged from 6.5 to 379.5 times higher than in unstressed controls. A natural population of P. simonii showed high nucleotide diversity (π T = 0.00880, θ w = 0.01192) and low linkage disequilibrium (r (2) ≥ 0.1, within 700 bp) across PsCBF4. Association analysis showed that nine SNPs (false discovery rate Q stress tolerance in P. simonii.

  12. Biochemical characterisation of isoprene synthase from poplar (Populus x canescens (Ait.) Sm.) and its expression in Arabidopsis thaliana L.; Biochemische Charakterisierung der Isoprensynthase aus der Graupappel (Populus x canescens (Ait.) Sm.) und ihre Expression in Arabidopsis thaliana L.

    Energy Technology Data Exchange (ETDEWEB)

    Bachl, A.

    2005-04-01

    It is known that a lot of plant species emit high amounts of isoprene, especially during high temperature periods. The physiological impact of isoprene biosynthesis and emission is currently still unknown. An enhanced heat tolerance as well as an antioxidant action of isoprene is mainly discussed. One of the main goals of this work was therefore to produce transgenic plants differing from the corresponding wildtype in their ability to synthesize and emit isoprene. Therefore, the isoprene synthase (ispS) gene from poplar (Populus x canescens), which was isolated by Miller et al. (2001) was used to transform Arabidopsis thaliana L., which is not a significant isoprene emitter. Prior to transformation the original DNA-sequence was extended by two different epitops, a nonapeptide HA epitope and six triplets for histidine resulting in a C-terminal His-tag, in order to get a labelled enzyme, which can be detected and cleaned up more easily afterwards. For proving the efficiency of the resulting proteins, the core enzymes without the transit peptide needed for the import of the protein, which is encoded in the nucleus, into the chloroplasts were expressed heterologous in E. coli. The HA epitope resulted in a complete loss of enzyme activity, while the His-tag led to a decreased enzyme activity of about 20%. For the Agrobacterium mediated transformation of A. thaliana the ispS with the C-terminal His-tag was used and cloned into the binary vector pBinAR under the control of a 35S promoter. 40 transgenic lines, which were selected by kanamycine resistance, have been achieved. The stable integration of ispS was confirmed on DNA- as well as on RNA level. The expression of ispS was proved in 38 of the 40 lines by PCR from cDNA. Furthermore the emission of the transgenic lines was studied by measuring whole plants for several hours. Five of the 40 lines showed significant higher isoprene emission rates being more than 2,5 fold higher than in the measured non emitting A

  13. Effect of arbuscular mycorrhizal inoculation on water status and photosynthesis of Populus cathayana males and females under water stress.

    Science.gov (United States)

    Li, Zhen; Wu, Na; Liu, Ting; Chen, Hui; Tang, Ming

    2015-02-27

    Drought is one of the most serious environmental limitations for poplar growth. Although the ways in which plants deal with water stress and the effects of arbuscular mycorrhizal (AM) formation have been well documented, little is known about how the male and female plants of Populus cathayana respond to drought and AM formation. We also aimed to investigate the potential role of AM fungi in maintaining gender balance. We tested the impact of drought and AM formation on water status and photosynthesis. The results suggested that both sexes showed similar responses to water stress: drought decreased the growth of stem length (GSL), growth of ground diameter (GGD), relative water content (RWC), increased the relative electrolyte leakage (REL), and limited the photosynthesis and chlorophyll fluorescence indexes. However, the responses of the two sexes to drought and AM formation differed to some extent. AM formation had positive effects on RWC, photosynthesis and the intrinsic water use efficiency (WUEi) but negative effects on the REL of males and females, especially under drought. AM formation enhanced the maximum quantum yield of photosystem II (PSII) (Fv/Fm), the actual quantum yield of PSII (ΦPSII), non-photochemical quenching (qN) and photochemical quenching (qP) under drought conditions, and had no significant effects under well-watered conditions except on the qP of males. Principal component analysis showed that males were significantly more drought tolerant than females, and AM formation enhanced drought tolerance, particularly among males, which suggested that AM fungi are beneficial for ecological stability and for P. cathayana survival under drought conditions.

  14. Variation in resistance to the rust fungus Melampsora larici-populina Kleb. in Populus nigra L. in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Štochlová P

    2016-02-01

    Full Text Available Differences in Populus nigra L. clone resistance to the rust fungus Melampsora larici-populina Kleb. (MLP were studied in field trials where infected trees were compared with fungicide-protected trees. MLP rust infections were assessed using a 6-point scale. Four parameters of poplar growth were also measured to gauge host response to infection: shoot thickness, shoot number at the end of the growing season, individual plant dry weight, and dry matter yield per unit area. Five of eight known pathogen virulence types were detected. Cumulative growth in shoot thickness in sprayed and unsprayed plots was similar in clones with high rust pathogen resistance, but significantly different in clones with low resistance. Clones with low resistance also exhibited delayed growth initiation in the year following infection, an effect attributed to lower food storage accumulated during the previous year, reflected in a reduction in stem diameter. Based on stem thickness measurements, it was confirmed growth ceased at the end of August. Average rust severity symptoms ranged from 2.75 to 4.22 on the 6-point scale. The percentage reduction for the various growth parameters resulting from rust infection ranged as follows: individual plant dry weight 5-64%; dry matter yield 21-66%; shoot number 17-46%; and stem diameter 1-35%. Exclusive of stem diameter, these reductions correlated with severity in MLP rust infection. The one exception was tolerance to rust infection displayed by one of the clones. Clones with the lowest growth reductions were 97/152 and 97/157. Growth and yield parameter variation as a result MLP resistance difference was observed among tested P. nigra clones. This variation can be viewed as confirmation that resistance observed in this study and P. nigra clones is a suite of quantitative traits. These findings have important implications for MLP resistance breeding programs.

  15. Contrasting responses in the growth and energy utilization properties of sympatric Populus and Salix to different altitudes: implications for sexual dimorphism in Salicaceae.

    Science.gov (United States)

    Lei, Yanbao; Chen, Ke; Jiang, Hao; Yu, Lei; Duan, Baoli

    2017-01-01

    Populus. However, no significant sexual difference was observed in S. magnifica for all the above parameters, thereby implying that the female-biased sex ratios in Salix cannot be explained in terms of the energy-use properties studied here. © 2016 Scandinavian Plant Physiology Society.

  16. Impact of simulated herbivory on water relations of aspen (Populus tremuloides) seedlings: the role of new tissue in the hydraulic conductivity recovery cycle.

    Science.gov (United States)

    Gálvez, David A; Tyree, M T

    2009-10-01

    Physiological mechanisms behind plant-herbivore interactions are commonly approached as input-output systems where the role of plant physiology is viewed as a black box. Studies evaluating impacts of defoliation on plant physiology have mostly focused on changes in photosynthesis while the overall impact on plant water relations is largely unknown. Stem hydraulic conductivity (k(h)), stem specific conductivity (k(s)), percent loss of hydraulic conductivity (PLC), CO(2) assimilation (A) and stomatal conductance (g(s)) were measured on well-irrigated 1-month-old Populus tremuloides (Michx.) defoliated and control seedlings until complete refoliation. PLC values of defoliated seedlings gradually increased during the refoliation process despite them being kept well irrigated. k(s) of defoliated seedlings gradually decreased during refoliation. PLC and k(s) values of control seedlings remained constant during refoliation. k(s) of new stems, leaf specific conductivity and A of leaves grown from new stems in defoliated and control seedlings were not significantly different, but g(s) was higher in defoliated than in control seedlings. The gradual increase of PLC and decrease of k(s) values in old stems after defoliation was unexpected under well-irrigated conditions, but appeared to have little impact on new stems formed after defoliation. The gradual loss of conductivity measured during the refoliation process under well-irrigated conditions suggests that young seedlings of P. tremuloides may be more susceptible to cavitation after herbivore damage under drought conditions.

  17. The control of soil polarization in Populus simonii and Quercus liaotungensis forests by forage litter on the Loess Plateau, P. R. China

    Institute of Scientific and Technical Information of China (English)

    Nhu Trung Luc; Zengwen Liu; Yuanhao Bing; Xiaoxi Zhang; Thi Huong Nguyen

    2015-01-01

    Soil polarization in pure forest stands affects the stability and sustainable development of the ecosystem. The most effective approaches to the prevention of soil polarization may be the use of forage litter as fertilizer or the direct establishment of tree-grass communities. We investigated monospecific plantations of Populus simonii and Quercus liaotungensis. Such plantations have been established throughout the Loess Plateau of China. A 120-day decomposition incubation experiment with forest humus soil mixed with 7 common leguminous forage litter species was performed to study the uses of forage litter in controlling soil polarization in pure forests. The addition of forage litter of Astragalus adsurgens, Lespedeza bicolor, and Vicia villosa to the soil of pure P. simonii forest clearly improved the soil quality, these forage species are suitable for planting with P. simonii, whereas Melilotus officinalis, Medicago sativa, and Onobrychis viciifolia litter produced obvious deterioration, thus these forages should not be planted with P. simonii. Coronilla varia litter showed no significant influence. The addition of forage litter of M. sativa to the soil of pure Q. liaotungensis forest clearly improved the soil quality, and C. varia and V. villosa also yielded improvements but were slightly less effective than M. sativa litter, these forages are suitable to be planted with Q. liaotungensis. However, L. bicolor showed obvious deterioration, followed by O. viciifolia and A. adsurgens, and M. officinalis had no significant influence. These spe-cies should not be planted with Q. liaotungensis.

  18. Sexual competition affects biomass partitioning, carbon-nutrient balance, Cd allocation and ultrastructure of Populus cathayana females and males exposed to Cd stress.

    Science.gov (United States)

    Chen, Juan; Duan, Baoli; Xu, Gang; Korpelainen, Helena; Niinemets, Ülo; Li, Chunyang

    2016-11-01

    Although increasing attention has been paid to plant adaptation to soil heavy metal contamination, competition and neighbor effects have been largely overlooked, especially in dioecious plants. In this study, we investigated growth as well as biochemical and ultrastructural responses of Populus cathayana Rehder females and males to cadmium (Cd) stress under different sexual competition patterns. The results showed that competition significantly affects biomass partitioning, photosynthetic capacity, leaf and root ultrastructure, Cd accumulation, the contents of polyphenols, and structural and nonstructural carbohydrates. Compared with single-sex cultivation, plants of opposite sexes exposed to sexual competition accumulated more Cd in tissues and their growth was more strongly inhibited, indicating enhanced Cd toxicity under sexual competition. Under intrasexual competition, females showed greater Cd accumulation, more serious damage at the ultrastructural level and greater reduction in physiological activity than under intersexual competition, while males performed better under intrasexual competition than under intersexual competition. Males improved the female microenvironment by greater Cd uptake and lower resource consumption under intersexual competition. These results demonstrate that the sex of neighbor plants and competition affect sexual differences in growth and in key physiological processes under Cd stress. The asymmetry of sexual competition highlighted here might regulate population structure, and spatial segregation and phytoremediation potential of both sexes in P. cathayana growing in heavy metal-contaminated soils.

  19. The influence of phosphorus availability and Laccaria bicolor symbiosis on phosphate acquisition, antioxidant enzyme activity, and rhizospheric carbon flux in Populus tremuloides.

    Science.gov (United States)

    Desai, Shalaka; Naik, Dhiraj; Cumming, Jonathan R

    2014-07-01

    Many forest tree species are dependent on their symbiotic interaction with ectomycorrhizal (ECM) fungi for phosphorus (P) uptake from forest soils where P availability is often limited. The ECM fungal association benefits the host plant under P limitation through enhanced soil exploration and increased P acquisition by mycorrhizas. To study the P starvation response (PSR) and its modification by ECM fungi in Populus tremuloides, a comparison was made between nonmycorrhizal (NM) and mycorrhizal with Laccaria bicolor (Myc) seedlings grown under different concentrations of phosphate (Pi) in sand culture. Although differences in growth between NM and Myc plants were small, Myc plants were more effective at acquiring P from low Pi treatments, with significantly lower k m values for root and leaf P accumulation. Pi limitation significantly increased the activity of catalase, ascorbate peroxidase, and guaiacol-dependent peroxidase in leaves and roots to greater extents in NM than Myc P. tremuloides. Phosphoenolpyruvate carboxylase activity also increased in NM plants under P limitation, but was unchanged in Myc plants. Formate, citrate, malonate, lactate, malate, and oxalate and total organic carbon exudation by roots was stimulated by P limitation to a greater extent in NM than Myc plants. Colonization by L. bicolor reduced the solution Pi concentration thresholds where PSR physiological changes occurred, indicating that enhanced Pi acquisition by P. tremuloides colonized by L. bicolor altered host P homeostasis and plant stress responses to P limitation. Understanding these plant-symbiont interactions facilitates the selection of more P-efficient forest trees and strategies for tree plantation production on marginal soils.

  20. Morphogenetic responses ofPopulus alba L. under salt stress

    Institute of Scientific and Technical Information of China (English)

    Mejda Abassi; Khaled Mguis; Zoubeir Béjaoui; Ali Albouchi

    2014-01-01

    The morphogenetic responses to salt stress of TunisianPopu-lus alba clones were studied in order to promote their plantation in dam-aged saline areas. One year-old plants of threeP. alba clones (MA-104, MA-195 and OG) were subjected to progressive salt stress by irrigation during two consecutive years. The plants were grown in a nursery, inside plastic receptacles containing sandy soil and were irrigated with tap water (control) or 3-6 g/l NaCl solution. During this study, leaf epinasty, elongation rate, vigor, internode length, plant architecture, and number of buds were evaluated. Test clone response was highly dependent on the applied treatment and degree of accommodation.The most pronounced alterations were induced under 6g/l of NaCl treatment including leaf epinasty, leaf elongation rate delay, vigor decrease, internode length shortening, and morphogenetic modifications. These responses were less noticeable in the MA-104 clone with respect to the two other clones. The salt effect induced a delay in the leaf elongation rate on the MA-195 and OG clones leading to an early leaf maturity. The vigour and internode length of the MA-104 clone was less affected than the other clones. The OG clone was the most salt-sensitive thus, it developed shorter branches and more buds number than MA-195 and MA-104. The effect of long-term salt stress was to induce early flowering of theP. alba clones which suggests that mechanism of salt accommodation could be devel-oped.

  1. Total Content of Polyphenols and Antioxidant Activity of Different Melliferous Plants

    OpenAIRE

    2016-01-01

    In this study polyphenols content and antioxidant activity of melliferous plants for the following: mint (Mentha pulegium), burdock (Arctium lappa), comfrey (Symphytum officinale), plantain (Pantago lanceolata), thyme (Thymus vulgaris), sage (Salvia officinalis), marigold (Calendula officinalis), small marshmallow (Althaea officinalis), echinacea (Echinaceea angustifolia) and black popular (Populus nigra) were investigated, using two different extraction methods. High content of polyp...

  2. Ten-Year Growth of Five Planted Hardwood Species Mechanical Weed Control on Sharkey Clay Soil

    Science.gov (United States)

    Roger M. Krinard; Harvey E. Kennedy

    1983-01-01

    Five hardwood species planted on Sharkey clay soil showed little practical difference in growth whether plots were mowed or diskedfor weed control in years 6 to 10, although disking had given better growth in the first 5 years. After 10 years, cottonwood (Populus deltoides Bartr. ex Marsh.) stem volume was at least three times greater than other species. Changes in...

  3. 77 FR 48367 - Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Ipomopsis...

    Science.gov (United States)

    2012-08-13

    ...) is called a ramet. A common example of a ramet is the aspen tree (Populus tremuloides), which appears... genes or alleles) lessens the ability of populations to cope with environmental change; mutations can... three plant species, nor did the commenter provide examples of such efforts. Without knowledge of...

  4. Twenty-One Genome Sequences from Pseudomonas Species and 19 Genome Sequences from Diverse Bacteria Isolated from the Rhizosphere and Endosphere of Populus deltoides

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Steven D [ORNL; Utturkar, Sagar M [ORNL; Klingeman, Dawn Marie [ORNL; Johnson, Courtney M [ORNL; Martin, Stanton [ORNL; Land, Miriam L [ORNL; Lu, Tse-Yuan [ORNL; Schadt, Christopher Warren [ORNL; Doktycz, Mitchel John [ORNL; Pelletier, Dale A [ORNL

    2012-01-01

    To aid in the investigation of the Populus deltoides microbiome we generated draft genome sequences for twenty one Pseudomonas and twenty one other diverse bacteria isolated from Populus deltoides roots. Genome sequences for isolates similar to Acidovorax, Bradyrhizobium, Brevibacillus, Burkholderia, Caulobacter, Chryseobacterium, Flavobacterium, Herbaspirillum, Novosphingobium, Pantoea, Phyllobacterium, Polaromonas, Rhizobium, Sphingobium and Variovorax were generated.

  5. Identification of five B-type response regulators as members of a multistep phosphorelay system interacting with histidine-containing phosphotransfer partners of Populus osmosensor

    Directory of Open Access Journals (Sweden)

    Bertheau Lucie

    2012-12-01

    Full Text Available Abstract Background In plants, the multistep phosphorelay signaling pathway mediates responses to environmental factors and plant hormones. This system is composed of three successive partners: hybrid Histidine-aspartate Kinases (HKs, Histidine-containing Phosphotransfer proteins (HPts, and Response Regulators (RRs. Among the third partners, B-type RR family members are the final output elements of the pathway; they act as transcription factors and clearly play a pivotal role in the early response to cytokinin in Arabidopsis. While interactions studies between partners belonging to the multistep phosphorelay system are mainly focused on protagonists involved in cytokinin or ethylene pathways, very few reports are available concerning partners of osmotic stress signaling pathway. Results In Populus, we identified eight B-type RR proteins, RR12-16, 19, 21 and 22 in the Dorskamp genotype. To assess HPt/B-type RR interactions and consequently determine potential third partners in the osmosensing multistep phosphorelay system, we performed global yeast two-hybrid (Y2H assays in combination with Bimolecular Fluorescence Complementation (BiFC assays in plant cells. We found that all B-type RRs are able to interact with HPt predominant partners (HPt2, 7 and 9 of HK1, which is putatively involved in the osmosensing pathway. However, different profiles of interaction are observed depending on the studied HPt. HPt/RR interactions displayed a nuclear localization, while the nuclear and cytosolic localization of HPt and nuclear localization of RR proteins were validated. Although the nuclear localization of HPt/RR interaction was expected, this work constitutes the first evidence of such an interaction in plants. Furthermore, the pertinence of this partnership is reinforced by highlighting a co-expression of B-type RR transcripts and the other partners (HK1 and HPts belonging to a potential osmosensing pathway. Conclusion Based on the interaction studies

  6. Improvement of drought and salt tolerance in Arabidopsis and Lotus corniculatus by overexpression of a novel DREB transcription factor from Populus euphratica.

    Science.gov (United States)

    Zhou, Mei-Liang; Ma, Jiang-Tao; Zhao, Yang-Min; Wei, Ya-Hui; Tang, Yi-Xiong; Wu, Yan-Min

    2012-09-10

    A novel DREB (dehydration-responsive element binding) gene, designated PeDREB2a, was isolated from the desert-grown tree, Populus euphratica Oliv. PeDREB2a is classified into the A-5 group of DREB subfamily based on multiple sequence alignment and phylogenetic characterization. Using semi-quantitative RT-PCR, we found that the PeDREB2a was greatly induced by drought, NaCl, low temperature, 1-naphthaleneacetic acid (NAA), 6-benzyl aminopurine (6-BA) and gibberellic acid (GA3) treatments in P. euphratica seedling. Yeast transactivity assay demonstrated that PeDREB2a gene encodes a transcription activator. Overexpression of PeDREB2a under the stress-inducible rd29A promotor in transgenic Arabidopsis and Lotus corniculatus forage plants resulted in enhanced tolerance to salt and drought stresses. The PeDREB2a overexpressing Arabidopsis lines showed higher root length and plant height and had elevated levels of soluble sugars and lower levels of malondialdehyde under stress conditions compared to control plants. The results revealed that PeDREB2a play an essential role as a DREB transcription factor in regulation of stress-responsive signaling in P. euphratica.

  7. Molecular Cloning of a Cellulose Synthase Gene PtoCesA1 from Populus tomentosa and Its Genetic Transformation in Tobacco

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A 3 125 bp cellulose synthase gene, PtoCesA1, which has a 98% identity to PtrCesA1 from Populus tremuloides,was cloned from cDNA prepared from secondary xylem of P. tomentosa. Four anti-expression vectors with different fragments of PtoCesA1, named as pBIPF, pBICC1, pBIPR and pBIBR, were constructed. Some traits of transformed tobacco of pBICC1, pBIPR and pBIBR differed from wild types, such as small leaves, "dwarf" phenotype and thinner xylem and fiber cell walls than wild plants consistent with a loss of cellulose. It indicated that the growth of transgenic tobacco was restrained by the expression of anti-PtoCesA1. Transgenic tobacco was obtained and the contents of cellulose and lignin were analyzed as well as the width and length of fiber cells, and xylem thickness for both transgenic and control plants. Transformed tobacco showed a different phenotype from control plants and it implied that PtoCesA1 was essential for the cellulose biosynthesis in poplar stems.

  8. Stress hardening under long-term cadmium treatment is correlated with the activation of antioxidative defence and iron acquisition of chloroplasts in Populus.

    Science.gov (United States)

    Solti, Ádám; Sárvári, Éva; Szöllősi, Erzsébet; Tóth, Brigitta; Mészáros, Ilona; Fodor, Ferenc; Szigeti, Zoltán

    2016-09-01

    Cadmium (Cd), a highly toxic heavy metal affects growth and metabolic pathways in plants, including photosynthesis. Though Cd is a transition metal with no redox capacity, it generates reactive oxygen species (ROS) indirectly and causes oxidative stress. Nevertheless, the mechanisms involved in long-term Cd tolerance of poplar, candidate for Cd phytoremediation, are not well known. Hydroponically cultured poplar (Populus jacquemontiana var. glauca cv. 'Kopeczkii') plants were treated with 10 μM Cd for 4 weeks. Following a period of functional decline, the plants performed acclimation to the Cd induced oxidative stress as indicated by the decreased leaf malondialdehyde (MDA) content and the recovery of most photosynthetic parameters. The increased activity of peroxidases (PODs) could have a great impact on the elimination of hydrogen peroxide, and thus the recovery of photosynthesis, while the function of superoxide dismutase (SOD) isoforms seemed to be less important. Re-distribution of the iron content of leaf mesophyll cells into the chloroplasts contributed to the biosynthesis of the photosynthetic apparatus and some antioxidative enzymes. The delayed increase in photosynthetic activity in relation to the decline in the level of lipid peroxidation indicates that elimination of oxidative stress damage by acclimation mechanisms is required for the restoration of the photosynthetic apparatus during long-term Cd treatment.

  9. Economic injury level for second-generation cottonwood leaf beetle (Coleoptera: Chrysomelidae) in two-year-old Populus.

    Science.gov (United States)

    Fang, Ying; Pedigo, Larry P; Colletti, Joe P; Hart, Elwood R

    2002-04-01

    The cottonwood leaf beetle, Chrysomela scripta F., is a major defoliating pest of Populus in North America. As the use of Populus in short-rotation woody crop plantations continues to increase, there are increasing economic and environmental needs to develop rational pest management programs to reduce the impact of this insect. Our objective was to determine the economic injury levels for the second generation of the cottonwood leaf beetle during plantation establishment. Integrating the cost of the management, market value, insect injury, and host response to the injury, the economic injury levels for second generation cottonwood leaf beetle on 2-yr-old Populus were determined to be from 0.2 to 0.9 egg masses per actively growing terminal.

  10. Characterization of NAC domain transcription factors implicated in control of vascular cell differentiation in Arabidopsis and Populus.

    Science.gov (United States)

    Grant, Emily H; Fujino, Takeshi; Beers, Eric P; Brunner, Amy M

    2010-07-01

    Wood has a wide variety of uses and is arguably the most important renewable raw material. The composition of xylem cell types in wood determines the utility of different types of wood for distinct commercial applications. Using expression profiling and phylogenetic analysis, we identified many xylem-associated regulatory genes that may control the differentiation of cells involved in wood formation in Arabidopsis and poplar. Prominent among these are NAC domain transcription factors (NACs). We studied NACs with putative involvement as negative (XND1 from Arabidopsis and its poplar orthologs PopNAC118, PopNAC122, PopNAC128, PopNAC129), or positive (SND2 and SND3 from Arabidopsis and their poplar orthologs PopNAC105, PopNAC154, PopNAC156, PopNAC157) regulators of secondary cell wall synthesis. Using quantitative PCR and in situ hybridization, we evaluated expression of these Populus NACs in a developmental gradient and in association with reaction wood and found that representatives from both groups were associated with wood-forming tissue and phloem fibers. Additionally, XND1 orthologs were expressed in mesophyll cells of developing leaves. We prepared transgenic Arabidopsis and poplar plants for overexpression of selected NACs. XND1 overexpression in poplar resulted in severe stunting. Additionally, poplar XND1 overexpressors lacked phloem fibers and showed reductions in cell size and number, vessel number, and frequency of rays in the xylem. Overexpression of PopNAC122, an XND1 ortholog, yielded an analogous phenotype in Arabidopsis. Overexpression of PopNAC154 in poplar reduced height growth and increased the relative proportion of bark versus xylem.

  11. Spatial distribution pattern and dynamics of the primary population in a natural Populus euphratica forest in Tarim Basin, Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    Lu HAN; Haizhen WANG; Zhengli ZHOU; Zhijun LI

    2008-01-01

    One 50 m × 50 m standard plot was sampled in a natural forest of Populus euphratica in Awati County, situated at the edge of the Tarim Basin, Xinjiang Uygur Autonomous Region, China. The field investigation was conducted with a contiguous grid quadrate method. By means of a test of variance/mean value ratio, aggregation intensity index and theoretical distribution models, the spatial distribution pattern and the dynamics of primary populations in P. euphratica forest were studied. The results showed that the spatial distribution pattern of two dominant arbor populations conformed to clumped distribution. The aggregation intensity of the P. euphra-tica population was higher than that of P. pruinosa popu- lation. The spatial distribution pattern of two companion plant populations in the shrub layer also conformed to clump type, though the aggregation intensity of Tamarix chinensis was higher. In the herb layer, the distribution patterns of Glycyrrhiza uralensis and Asparagus persicus conformed respectively to a clumped pattern and a ran-dom pattern. The results of a Taylor power method test and Iwao's m2-x regression model also verified that both P. euphratica and P. pruinosa populations belong to a clumped pattern. Although the distribution pattern of P. pruinosa population at different development stages all belonged to a clumped distribution pattern, the aggrega-tion intensity dropped gradually along with age develop-ment. The distribution patterns of the P. euphratica population at different development stages changed from random type to clumped type, and further to random type. The differences in spatial distribution patterns of different populations at different development stages were related not only to ecological and biological characteris-tics of each species in the communities in the light of competitive exclusion principle among the populations, but were also closely related to the habitats in which the species lived in.

  12. Erfassung, Identifizierung, Vermehrung und Wiederansiedlung der Schwarzpappel Populus nigra in Sachsen-Anhalt

    OpenAIRE

    2013-01-01

    Durch den Flußlauf der Elbe und ihre Nebenflüsse sind in Sachsen-Anhalt aktuelle und potentielle Vorkommensgebiete der Schwarzpappel (Populus nigra) vorhanden. Die natürlichen Standorte der Schwarzpappel sind die Übergangszonen von Weichholzund Hartholzaue (ELLENBERG 1996), wie sie an naturnahen Flußufern zu finden sind. Im Gegensatz zu anderen Baumarten erträgt die Schwarzpappel wie auch Baumweidenarten Hochwasserstände von bis zu 90 Tagen und damit mittlere Hochwässer. Auf Grund der Konkurr...

  13. Populations of aspen (Populus tremuloides Michx.) with different evolutionary histories differ in their climate occupancy.

    Science.gov (United States)

    Greer, Burke T; Still, Christopher; Howe, Glenn T; Tague, Christina; Roberts, Dar A

    2016-05-01

    Quaking aspens (Populus tremuloides Michx.) are found in diverse habitats throughout North America. While the biogeography of aspens' distribution has been documented, the drivers of the phenotypic diversity of aspen are still being explored. In our study, we examined differences in climate between northern and southwestern populations of aspen, finding large-scale differences between the populations. Our results suggest that northern and southwestern populations live in distinct climates and support the inclusion of genetic and phenotypic data with species distribution modeling for predicting aspens' distribution.

  14. Temporal heterogeneity of Populus euphratica seed rain in Ejina Oasis, China

    OpenAIRE

    Cao, Dechang; Li, Jingwen; Chen,Weiqiang; Li, Junqing

    2009-01-01

    The seed rain of Populus euphratica in Ejina Oasis was continuously studied in the years of 2004, 2006, 2007, and 2008. The duration of P. euphratica seed rain in a community was usually 2 to 3 weeks, with a peak period of 7 to 14 days. Approximately 90% of the total number of seeds were dispersed in the peak period, and for a single day most seeds fell between the hours of 10:00 to 16:00. It was found that the seed rain of P. euphratica was determined by a combination of biological rhythms a...

  15. Effects of antibiotics on plantlet regeneration via organogenesis in Populus euphratica

    Institute of Scientific and Technical Information of China (English)

    Ding Xia; Chen Xiao-yang; Li Wei; Du Zhi-yan

    2006-01-01

    Four antibiotics, kanamycin, geneticin, carbenicillin and cefotaxime, were evaluated for their effect on the regeneration of adventitious buds, shoot differentiation, rooting from regenerated shoots of Populus euphratica as well as on their control of Agrobacterium-mediated transformations. Results showed that the optimum concentration ranges of kanamycin and geneticin were 15-20 and 10-15 mg·L-1 at the stage of transgenic plantlet selection. The inhibitory effects of cefotaxime and carbenicillin varied among different genotypes of Agrobacterium. The inhibition of cefotaxime on Agrobacterium C58 was stronger than that of carbenicillin.LBA4404 and their optimum concentrations were both 150 mg·L-1.

  16. Commercial wood of clones of genus Populus: Relationship between growth and density of wood with inorganic nutrients

    OpenAIRE

    Senisterra, Gabriela; Marlats, Raúl M.; Ducid, María G.

    2008-01-01

    El objetivo del trabajo fue determinar sobre 10 clones de álamos, provenientes de cruzamientos intraespecíficos de Populus deltoides e interespecíficos de Populus x canadensis, implantados en Teodelina, Santa Fe, Argentina (34°09' S; 61°15' W), la concentración de nutrientes inorgánicos en su corteza y leño, y sus relaciones con los volúmenes comerciales alcanzados a los 9 años de edad y la densidad bási...

  17. Fractionation of alkali-solubilized hemicelluloses from delignified Populus gansuensis: structure and properties.

    Science.gov (United States)

    Peng, Feng; Ren, Jun-Li; Xu, Feng; Bian, Jing; Peng, Pai; Sun, Run-Cang

    2010-05-12

    The dewaxed cell walls of Populus gansuensis were delignified with NaClO(2) and then sequentially extracted with 0.25, 0.5, and 1.0 M KOH under a solid to liquid ratio of 1: 25 (g mL(-1)) at 25 degrees C for 10 h. The successive treatments together resulted in the dissolution of 83.7% of original hemicelluloses. The solubilized hemicellulosic fractions were further fractionated into six hemicellulosic subfractions by an iodine-complex precipitation technique. Their chemical and physical characteristics were determined by HPAEC, GPC, FT-IR, and (1)H and (13)C NMR spectroscopy. Neutral sugar composition and molecular weight analysis showed that, for each extract, the hemicellulosic subfractions that precipitated with aqueous potassium iodide-iodine had lower overall uronic acid/xylose (Uro/Xyl) ratios and higher molecular weights (M(w)) than those remaining in the solution. FT-IR, (1)H, and (13)C NMR spectroscopy analysis indicated that the alkali-soluble hemicelluloses of Populus gansuensis had a structure composed of the (1 --> 4)-linked beta-D-xylopyranosyl backbone with 4-O-methyl-alpha-D-glucuronic acid attached to O-2 of the xylose residues.

  18. An Elite Variety of Populus deltoides‘Beiyang’%杨树良种‘北杨’

    Institute of Scientific and Technical Information of China (English)

    曹国玉; 李继祥; 买买提库尔班·阿力; 李开花; 胡建军

    2016-01-01

    The‘Beiyang’,male clone and intraspecific hybrid of Populus deltoides hybrid,was selected from the progeny of Populus deltoides‘Nankang’× P. deltoides‘D175’by the way of artificial control cross pollination. Average DBH,height and volume of nine-year-old‘Beiyang’were 21. 3 cm,20. 4 m and 0. 250 m3 ,which were 49. 9% greater than the control‘2025’. The elite variety has the fine characteristics such as straight trunk,middle crown,fast-growing, strong resistance to Anoplophora glaberipennis and soil barren tolerance.%‘北杨’是通过人工控制授粉选育而成,雄株,为美洲黑杨种内杂种,其母本为南抗杨,父本为‘D175’。9年生平均胸径21.3 cm,平均树高20.4 m,单株材积0.250 m3,比对照‘中林2025杨’材积生长量提高49.9%。树冠长卵形,干形通直,冠幅中等,早期速生,抗光肩星天牛,耐瘠薄。

  19. Hot water and dilute acid pretreatment of high and low specific gravity Populus deltoides clones.

    Science.gov (United States)

    Martin, Elizabeth M; Bunnell, Kris A; Lau, Ching-Shuan; Pelkki, Matthew H; Patterson, David W; Clausen, Edgar C; Smith, James A; Carrier, Danielle Julie

    2011-02-01

    Populus sp. are hardwood feedstocks that grow in forest management areas that are logged for softwoods; however, they are also being considered as an energy-destined feedstock. The objective of this work was to determine the effect of xylose yield from dilute acid and hot water pretreatments performed in unstirred batch stainless steel reactors at temperatures ranging from 140 to 200°C. Populus deltoides clones S13C20 and S7C15 used in this study originated from Eastern Texas and were cultivated for 14 years in Pine Tree, AR. P. deltoides clones S13C20 and S7C15 had specific gravities of 0.48 and 0.40, respectively. Bark and wood were examined separately. As expected, hot water pretreatments, in the tested temperature range, resulted in very little direct xylose recovery. However, the 140°C dilute acid pretreatment of the lower specific gravity clone, S7C15, wood yielded the highest average xylose recovery of 56%. This condition also yielded the highest concentration of furfural, 9 mg/g sample, which can be inhibitory to the fermentation step. The highest xylose recovery from bark samples, 31%, was obtained with clone S7C15, using the 160°C dilute acid pretreatment for 60 min.

  20. Differential detection of genetic Loci underlying stem and root lignin content in Populus.

    Directory of Open Access Journals (Sweden)

    Tongming Yin

    Full Text Available In this study, we established a comprehensive genetic map with a large number of progeny from a three-generation hybrid Populus intercross, and phenotyped the lignin content, S/G ratio and 28 cell wall subcomponents both in stems and roots for the mapping individuals. Phenotypic analysis revealed that lignin content and syringyl-to-guaiacyl (S/G ratio using pyrolysis molecular beam mass spectroscopy (pyMBMS varied among mapping individuals. Phenotypic analysis revealed that stem lignin content is significantly higher than that in root and the quantified traits can be classified into four distinct groups, with strong correlations observed among components within organs. Altogether, 179 coordinating QTLs were detected, and they were co-localized into 49 genetic loci, 27 of which appear to be pleiotropic. Many of the detected genetic loci were detected differentially in stem and root. This is the first report of separate genetic loci controlling cell wall phenotypes above and below ground. These results suggest that it may be possible to modify lignin content and composition via breed and/or engineer as a means of simultaneously improving Populus for cellulosic ethanol production and carbon sequestration.

  1. The transcriptome of Populus in elevated CO2 reveals increased anthocyanin biosynthesis during delayed autumnal senescence

    Energy Technology Data Exchange (ETDEWEB)

    Tallis, M.J.; Rogers, A.; Lin, Y.; Zhang, J.; Street, N. R.; Miglietta, F.; Karnosky, D. F.; Angelis, P. D.; Calfapietra, C.; Taylor, G.

    2010-03-01

    The delay in autumnal senescence that has occurred in recent decades has been linked to rising temperatures. Here, we suggest that increasing atmospheric CO{sub 2} may partly account for delayed autumnal senescence and for the first time, through transcriptome analysis, identify gene expression changes associated with this delay. Using a plantation of Populus x euramericana grown in elevated [CO{sub 2}] (e[CO{sub 2}]) with free-air CO{sub 2} enrichment (FACE) technology, we investigated the molecular and biochemical basis of this response. A Populus cDNA microarray was used to identify genes representing multiple biochemical pathways influenced by e[CO{sub 2}] during senescence. Gene expression changes were confirmed through real-time quantitative PCR, and leaf biochemical assays. Pathways for secondary metabolism and glycolysis were significantly up-regulated by e[CO{sub 2}] during senescence, in particular, those related to anthocyanin biosynthesis. Expressed sequence tags (ESTs) representing the two most significantly up-regulated transcripts in e[CO{sub 2}], LDOX (leucoanthocyanidin dioxgenase) and DFR (dihydroflavonol reductase), gave (e[CO{sub 2}]/ambient CO{sub 2} (a[CO{sub 2}])) expression ratios of 39.6 and 19.3, respectively. We showed that in e[CO{sub 2}] there was increased autumnal leaf sugar accumulation and up-regulation of genes determining anthocyanin biosynthesis which, we propose, prolongs leaf longevity during natural autumnal senescence.

  2. Reproductive characteristics of a Populus euphratica population and prospects for its restoration in China.

    Directory of Open Access Journals (Sweden)

    Dechang Cao

    Full Text Available Populus euphratica is a dominant tree in riparian ecosystems in arid areas of northwest China, but it fails to regenerate in these systems. This study evaluates causes for the failure of sexual and asexual regeneration of this species in the wild. P. euphratica disperses as many as 85743 seeds/m(2 during summer, and the seeds germinate to 92.0% in distilled water and to 60.8% on silt. However, very few seeds (3.6% can germinate on unflooded soil. The seed-rain season is prolonged by temporal variability in seed dispersal among individuals, which ensures that seedling emergence can occur during favorable conditions (i.e., floods and rainfall. As a result of water shortage and river channeling due to water usage and altered river flows, there are no safe sites on river banks for seed germination, which has led to the failure of P. euphratica to regenerate from seed. Root suckers of P. euphratica were present in 86% of the forest gaps investigated. However, extensive grazing has destroyed many of them and thus has reduced this form of regeneration. This research suggests that human activities are resulting in the failure of P. euphratica to regenerate. Changes in land management such as reduced use of concrete canals in Populus forests and/or reduced sheep grazing in these areas may promote their regeneration.

  3. Two poplar-associated bacterial isolates induce additive favorable responses in a constructed plant-microbiome system

    Directory of Open Access Journals (Sweden)

    Collin M Timm

    2016-04-01

    Full Text Available The biological function of the plant-microbiome system is the result of contributions from the host plant and microbiome members. The Populus root microbiome is a diverse community that has high abundance of β- and γ-Proteobacteria, both classes which include multiple plant-growth promoting representatives. To understand the contribution of individual microbiome members in a community, we studied the function of a simplified community consisting of Pseudomonas and Burkholderia bacterial strains isolated from Populus hosts and inoculated on axenic Populus cutting in controlled laboratory conditions. Both strains increased lateral root formation and root hair production in Arabidopsis plate assays and are predicted to encode for different functions related to growth and plant growth promotion in Populus hosts. Inoculation individually, with either bacterial isolate, increased root growth relative to uninoculated controls, and while root area was increased in mixed inoculation, the interaction term was insignificant indicating additive effects of root phenotype. Complementary data including photosynthetic efficiency, whole-transcriptome gene expression and GC-MS metabolite expression data in individual and mixed inoculated treatments indicate that the effects of these bacterial strains are unique and additive. These results suggest that the function of a microbiome community may be predicted from the additive functions of the individual members.

  4. Impact of non-native plant removal on lizards in riparian habitats in the southwestern United States

    Science.gov (United States)

    Heather L. Bateman; Alice Chung-MacCoubrey; Howard L. Snell

    2008-01-01

    Many natural processes in the riparian cottonwood (Populus deltoides) forest of the Middle Rio Grande (MRG) in the southwestern United States have been disrupted or altered, allowing non-native plants such as saltcedar (Tamarix spp.) and Russian olive (Elaeagnus angustifolia) to establish. We investigated...

  5. Field performance of Populus in short-rotation intensive culture plantations in the north-central U.S.

    Science.gov (United States)

    Edward A. Hansen; Michael E. Ostry; Wendell D. Johnson; David N. Tolsted; Daniel A. Netzer; William E. Berguson; Richard B. Hall

    1994-01-01

    Describes a network of short-rotation, Populus research and demonstration plantations that has been established across a 5-state region in the north-central U.S. to identify suitable hybrid poplar clones for large-scale biomass plantations in the region. Reports 6-year results.

  6. Biomass traits and candidate genes for bioenergy revealed through association genetics in coppiced European Populus nigra (L.)

    NARCIS (Netherlands)

    Allwright, Mike Robert; Payne, Adrienne; Emiliani, Giovanni; Milner, Suzanne; Viger, Maud; Rouse, Franchesca; Keurentjes, Joost J.B.; Bérard, Aurélie; Wildhagen, Henning; Faivre-Rampant, Patricia; Polle, Andrea; Morgante, Michele; Taylor, Gail

    2016-01-01

    Background: Second generation (2G) bioenergy from lignocellulosic feedstocks has the potential to develop as a sustainable source of renewable energy; however, significant hurdles still remain for large-scale commercialisation. Populus is considered as a promising 2G feedstock and understanding t

  7. Comparative physiology of allopatric Populus species: geographic clines in photosynthesis, height growth, and carbon isotope discrimination in common gardens.

    Science.gov (United States)

    Soolanayakanahally, Raju Y; Guy, Robert D; Street, Nathaniel R; Robinson, Kathryn M; Silim, Salim N; Albrectsen, Benedicte R; Jansson, Stefan

    2015-01-01

    Populus species with wide geographic ranges display strong adaptation to local environments. We studied the clinal patterns in phenology and ecophysiology in allopatric Populus species adapted to similar environments on different continents under common garden settings. As a result of climatic adaptation, both Populus tremula L. and Populus balsamifera L. display latitudinal clines in photosynthetic rates (A), whereby high-latitude trees of P. tremula had higher A compared to low-latitude trees and nearly so in P. balsamifera (p = 0.06). Stomatal conductance (g s) and chlorophyll content index (CCI) follow similar latitudinal trends. However, foliar nitrogen was positively correlated with latitude in P. balsamifera and negatively correlated in P. tremula. No significant trends in carbon isotope composition of the leaf tissue (δ(13)C) were observed for both species; but, intrinsic water-use efficiency (WUEi) was negatively correlated with the latitude of origin in P. balsamifera. In spite of intrinsically higher A, high-latitude trees in both common gardens accomplished less height gain as a result of early bud set. Thus, shoot biomass was determined by height elongation duration (HED), which was well approximated by the number of days available for free growth between bud flush and bud set. We highlight the shortcoming of unreplicated outdoor common gardens for tree improvement and the crucial role of photoperiod in limiting height growth, further complicating interpretation of other secondary effects.

  8. Research Progress on the Salt-tolerance of Populus spp.%杨树耐盐性研究进展

    Institute of Scientific and Technical Information of China (English)

    陈必胜; 汪晓沙; 黄梅; 朱继军; 林登贵; 李梅玲; 李萍; 曾丽

    2012-01-01

    杨树生长迅速、生物产量高,是一种世界性的造林树种,一些杨树具有较强的耐盐性,对盐碱化土地的利用和开发具有重要价值.对盐胁迫下杨树的植物学特征、生理生化指标变化、耐盐分子机制和遗传改良策略进行了综述,并对深入地解析杨树耐盐分子机制应采取策略和在生产中应用前景进行了讨论,以期为筛选和培育耐盐杨树品种提供借鉴和参考.%Populus spp. is a world-wide tree species for forestation with rapid growth and higher biomass. Due to stronger salt-tolerance of some Populus spp. varieties, they may be used to exploit the potential value of the salinized land. Several properties of Populus spp. under salt stress were reviewed, including the botanical features, physiological and biochemical indexes, and molecular response; furthermore, the molecular mechanism and genetic improvement strategies for poplar salt-tolerance were outlined and discussed, so as to provide reference for screening and developing Populus spp. variety with slat tolerance.

  9. Seed development in Phaseolus vulgaris L., Populus nigra L., and Ranunculus sceleratus L. with special reference to the microtubular cytoskeleton

    NARCIS (Netherlands)

    XuHan, X.

    1995-01-01

    In this thesis, seed development is investigated in celery-leafed buttercup ( Ranunculus sceleratus L.), bean ( Phaseolus vulgaris L.) and poplar ( Populus nigra L.). Developing embryos, endosperms and seed coats are investigate

  10. Expression of multiple resistance genes enhances tolerance to environmental stressors in transgenic poplar (Populus × euramericana 'Guariento'.

    Directory of Open Access Journals (Sweden)

    Xiaohua Su

    Full Text Available Commercial and non-commercial plants face a variety of environmental stressors that often cannot be controlled. In this study, transgenic hybrid poplar (Populus × euramericana 'Guariento' harboring five effector genes (vgb, SacB, JERF36, BtCry3A and OC-I were subjected to drought, salinity, waterlogging and insect stressors in greenhouse or laboratory conditions. Field trials were also conducted to investigate long-term effects of transgenic trees on insects and salt tolerance in the transformants. In greenhouse studies, two transgenic lines D5-20 and D5-21 showed improved growth, as evidenced by greater height and basal diameter increments and total biomass relative to the control plants after drought or salt stress treatments. The improved tolerance to drought and salt was primarily attributed to greater instantaneous water use efficiency (WUEi in the transgenic trees. The chlorophyll concentrations tended to be higher in the transgenic lines under drought or saline conditions. Transformed trees in drought conditions accumulated more fructan and proline and had increased Fv/Fm ratios (maximum quantum yield of photosystem II under waterlogging stress. Insect-feeding assays in the laboratory revealed a higher total mortality rate and lower exuviation index of leaf beetle [Plagiodera versicolora (Laicharting] larvae fed with D5-21 leaves, suggesting enhanced insect resistance in the transgenic poplar. In field trials, the dominance of targeted insects on 2-year-old D5-21 transgenic trees was substantially lower than that of the controls, indicating enhanced resistance to Coleoptera. The average height and DBH (diameter at breast height of 2.5-year-old transgenic trees growing in naturally saline soil were 3.80% and 4.12% greater than those of the control trees, but these increases were not significant. These results suggested that multiple stress-resistance properties in important crop tree species could be simultaneously improved, although

  11. Application of Five Light-Response Models in the Photosynthesis of Populus × Euramericana cv. 'Zhonglin46' Leaves.

    Science.gov (United States)

    Fang, Lidong; Zhang, Shuyong; Zhang, Guangcan; Liu, Xia; Xia, Xuanxuan; Zhang, Songsong; Xing, Wei; Fang, Xiaochen

    2015-05-01

    The light-response curve of photosynthesis is an important tool used to study plant ecophysiology and can provide a scientific basis for the response of plant photosynthetic characteristics to environmental factors. At present, there are five common light-response models of photosynthesis. To gain deeper insight into the applicability of different light-response models of photosynthesis and the photosynthetic physiological characteristics of Populus euramericana cv. 'Zhonglin46', two typical light-response curves of photosynthesis in P. euramericana cv. 'Zhonglin46' leaves, one under drought stress and the other under control conditions, were measured using a CIRAS-2 portable photosynthesis system. The light-response data were divided into two groups: one set of data was used to fit light-response curves, and the other set of data was used to test them. The accuracy of the fitting and the predictions of the different models were evaluated by mean square error and mean absolute error. The results showed that the light-response curves of P. euramericana cv. 'Zhonglin46' under drought stress matched the light-saturated inhibition type and that those under the control condition matched the approaching light-saturation type. The two new models (i.e., the modified rectangular hyperbola model and modified exponential model) fit the two light-response curves and their characteristic parameters well, and the fitting results of the two models were similar. Conversely, the three traditional models (i.e., the rectangular hyperbola model, nonrectangular hyperbola model, and exponential model) did not fit the two light-response curves well; in particular, they overestimated the maximum net photosynthetic rate, underestimated the light saturation point (LSP), and did not fit the net photosynthetic rate during the light-saturated stage. The LSP calculated by the "linear method" combined with the traditional models was significantly lower than the measured values; additionally, the

  12. Brine shrimp toxicity and antimalarial activity of some plants traditionally used in treatment of malaria in Msambweni district of Kenya.

    Science.gov (United States)

    Nguta, J M; Mbaria, J M

    2013-07-30

    In Kenya, most people especially in rural areas use traditional medicine and medicinal plants to treat many diseases including malaria. Malaria is of national concern in Kenya, in view of development of resistant strains of Plasmodium falciparum to drugs especially chloroquine, which had been effective and affordable. There is need for alternative and affordable therapy. Many antimalarial drugs have been derived from medicinal plants and this is evident from the reported antiplasmodial activity. The present study reports on the in vivo antimalarial activity and brine shrimp lethality of five medicinal plants traditionally used to treat malaria in Msambweni district, Kenya. A total of five aqueous crude extracts from different plant parts used in traditional medicine for the treatment of malaria were evaluated for their in vivo antimalarial activity using Plasmodium berghei infected Swiss mice and for their acute toxicity using Brine shrimp lethality test. The screened crude plant extracts suppressed parasitaemia as follows: Azadirachta indica (L) Burm. (Meliaceae), 3.1%; Dichrostachys cinerea (L) Wight et Arn (Mimosaceae), 6.3%; Tamarindus indica L. (Caesalpiniaceae), 25.1%; Acacia seyal Del. (Mimosaceae) 27.8% and Grewia trichocarpa Hochst ex A.Rich (Tiliaceae) 35.8%. In terms of toxicity, A.indica root bark extract had an LC50 of 285.8 µg/ml and was considered moderately toxic. T.indica stem bark extract and G.trichocarpa root extract had an LC50 of 516.4 and 545.8 µg/ml respectively and were considered to be weakly toxic while A.seyal and D.cinerea root extracts had a LC50>1000 µg/ml and were therefore considered to be non toxic. The results indicate that the aqueous extracts of the tested plants when used alone as monotherapy had antimalarial activity which was significantly different from that of chloroquine (P≤0.05). The results also suggest that the anecdotal efficacy of the above plants reported by the study community is related to synergism of

  13. Ecophysiological Competence of Populus alba L., Fraxinus angustifolia Vahl., and Crataegus monogyna Jacq. Used in Plantations for the Recovery of Riparian Vegetation

    Science.gov (United States)

    Manzanera, Jose A.; Martínez-Chacón, Maria F.

    2007-12-01

    In many semi-arid environments of Mediterranean ecosystems, white poplar ( Populus alba L.) is the dominant riparian tree and has been used to recover degraded areas, together with other native species, such as ash ( Fraxinus angustifolia Vahl.) and hawthorn ( Crataegus monogyna Jacq.). We addressed three main objectives: (1) to gain an improved understanding of some specific relationships between environmental parameters and leaf-level physiological factors in these riparian forest species, (2) to compare the leaf-level physiology of these riparian species to each other, and (3) to compare leaf-level responses within native riparian plots to adjacent restoration plots, in order to evaluate the competence of the plants used for the recovery of those degraded areas. We found significant differences in physiological performance between mature and young white poplars in the natural stand and among planted species. The net assimilation and transpiration rates, diameter, and height of white poplar plants were superior to those of ash and hawthorn. Ash and hawthorn showed higher water use efficiency than white poplar. White poplar also showed higher levels of stomatal conductance, behaving as a fast-growing, water-consuming species with a more active gas exchange and ecophysiological competence than the other species used for restoration purposes. In the restoration zones, the planted white poplars had higher rates of net assimilation and water use efficiency than the mature trees in the natural stand. We propose the use of white poplar for the rapid restoration of riparian vegetation in semi-arid Mediterranean environments. Ash and hawthorn can also play a role as accompanying species for the purpose of biodiversity.

  14. Sulfate Metabolites of 4-Monochlorobiphenyl in Whole Poplar Plants

    OpenAIRE

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

    2012-01-01

    4-Monochlorobiphenyl (PCB3) has been proven to be transformed into hydroxylated metabolites of PCB3 (OH-PCB3s) in whole poplar plants in our previous work. However, hydroxylated metabolites of PCBs, including OH-PCB3s, as the substrates of sulfotransferases have not been studied in many organisms including plants in vivo. Poplar (Populus deltoides × nigra, DN34) was used to investigate the further metabolism from OH-PCB3s to PCB3 sulfates because it is a model plant and one that is frequently...

  15. 不同生长势美洲黑杨转录组差异分析%Analysis of Transcriptome Differences among Populus deltoides with Different Growth Potentials

    Institute of Scientific and Technical Information of China (English)

    丁昌俊; 张伟溪; 高暝; 黄秦军; 褚延广; 苏晓华

    2016-01-01

    及外来物质的降解和代谢途径。【结论】杂种优势的形成,可能是由于相关基因的显著差异表达,调控光合作用、物质代谢吸收等与生长紧密联系的代谢活动,进而促进生长优势的产生。%[Objective]The study was intended to study the gene expression profile of F1 hybrids of Populus deltoides to reveal the mechanism of hybrid vigor at the gene expression level. [Method]We sequenced the transcriptomes of three super-parent hybrids F1 ( H1 ,H2 ,H3 ) ,two low-parent hybrids ( L1 ,L2 ) ,and their parents ( Q1 ,Q2 ) using high throughput sequencing. [Result]We obtained a total of 171 154 127 reads,with an average length of 200 bp and a total of 31. 32 Gb size. After filtering,we aligned the clean reads to the reference genome of Populus trichocarpa and 61. 89%of the clean reads could be aligned to the reference genome. The comparison between super-parent hybrids F1 and parents ( H Vs Q) revealed that 342 genes were differently expressed (87 up-regulated and 255 down-regulated) . We termed the different expressed gene as DEG thereafter. Meanwhile,577 DEGs ( 146 up-regulated and 431 down-regulated ) were identified by comparing low-parent hybrids F1 with parents(L Vs Q),and 486 DEGs (200 up-regulated and 286 down-regulated) were identified by comparison of low-parent hybrids F1 and super-parent hybrid F1(H Vs L). 377 genes that were highly related to the hybrid vigor were identified,of which 4 genes down-regulated expressed in H Vs Q,L Vs Q and H Vs L,72 genes down-regulated expressed both in H Vs Q and L Vs Q,129 genes differentially expressed ( 19 up-regulated and 110 down-regulated) both in H Vs Q and H Vs L,170 genes differentially expressed both in L Vs Q and H Vs L. The functional analysis and pathway analysis demonstrated that there were 167,233 and 288 DGEs could be categorized into 46,45 and 51 functional groups,respectively. In the three main categories ( cellular component, molecular function

  16. Significance of stigma receptivity in intergeneric cross-pollination of Salix × Populus

    Directory of Open Access Journals (Sweden)

    Elżbieta Zenkteler

    2016-09-01

    Full Text Available The pollen–stigma interaction plays an important role in reproductive process and has been continuously studied in many interspecific and intergeneric crossing experiments. The aim of this study was to investigate stigma receptivity (SR of willow in order to determine the most suitable period for its pollination with poplar pollen and improve the effectiveness of Salix × Populus crosses. Tissue samples were examined histologically using light, epifluorescent, scanning, and transmission electron microscopy. Willow SR was determined by stigma morphological traits, test of pollen germination rate, Peroxtesmo test of peroxidase and esterase activity on stigma surface as well as papilla ultrastructure at anthesis. We have ascertained that the SR duration in willow is short, lasting from 1 to 2 DA. The poplar pollen germination rate on willow stigmas on 1 DA ranged from 26.3 to 11.2%.

  17. Conversion of water consumption of a single tree and a forest stand of Populus euphratica

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-you; MENG Tong-tong; KANG Er-si

    2008-01-01

    Our study dear with the determination of sapwood sap flow of a single Populus euphratica tree by heat pulse technique and the calculation of water consumption of an entire forest stand, given the correlation between sap flow and sapwood area of P. euphratica. The relation between diameter at breast height (DBH) and sapwood area constitutes a powerful model; these variables are highly correlated. By means of an analysis of DBH in the sample plot, the distribution of the sapwood area of the forest land was obtained and the water consumption of this P. euphratica forest, in the lower reaches of the Heihe River, calculated as 214.9 mm by standard specific conductivity of the sample tree.

  18. [Spatial structural characteristics of natural Populus davidiana - Betula platyphylla secondary forest].

    Science.gov (United States)

    Shao, Fang-Li; Yu, Xin-Xiao; Song, Si-Ming; Zhao, Yang

    2011-11-01

    This paper analyzed the spatial structural characteristics of natural Populus davidiana - Betula platyphylla secondary forest in a 4 hm2 plot of Mulan Paddock, based on the diameter distribution and the spatial structure parameters mingling degree, neighborhood comparison, and angle index. In the forest, the diameter distribution of the stands presented as an inverse 'J' curve, the average mingling degree was 0.4, with the individuals at weak and zero mingling degree reached 51.6%, and the average mingling degree of P. davidiana and B. platyphylla was 0.25 and 0.39, respectively. The neighborhood comparison based on the diameter at breast height (DBH) and tree height was almost the same, suggesting that the P. davidiana and B. platyphylla were in the transition state from subdominant to middle. The horizontal distribution pattern had a close relation to the minimum measured DBH, being clustered when the DBH was > or = 1 cm and or = 6 cm.

  19. Scale dependence of disease impacts on quaking aspen (Populus tremuloides) mortality in the southwestern United States

    Science.gov (United States)

    Bell, David M.; Bradford, John B.; Lauenroth, William K.

    2015-01-01

    Depending on how disease impacts tree exposure to risk, both the prevalence of disease and disease effects on survival may contribute to patterns of mortality risk across a species' range. Disease may accelerate tree species' declines in response to global change factors, such as drought, biotic interactions, such as competition, or functional traits, such as allometry. To assess the role of disease in mediating mortality risk in quaking aspen (Populus tremuloides), we developed hierarchical Bayesian models for both disease prevalence in live aspen stems and the resulting survival rates of healthy and diseased aspen near the species' southern range limit using 5088 individual trees on 281 United States Forest Service Forest Inventory and Analysis plots in the southwestern United States.

  20. TCF Bleaching of Populus tomentosa Kraft Pulps with H2O2 Pretreatment under Acid Condition

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The process of peroxide bleaching of Populus tomentosa kraft pulp with H2O2 pretreatment under acid condition was studied. The variations of pulp characteristics such as brightness, Kappa number and viscosity during the peroxide bleaching process were discussed and the concept of the A/B value was presented for the first time. The results show that acid pretreatment with H2O2 is essential to improve pulp brightness and avoid viscosity loss. The conclusion is reached that the A/B value has great influence on pulp properties when the total amount of peroxide used in the bleaching process is 2%-5%. Pulp with a high viscosity and brightness can be obtained when A/B is about 0.15.

  1. The use of the white poplar (Populus alba L.) biomass as fuel

    Institute of Scientific and Technical Information of China (English)

    Tatiana Griu; Aurel Lunguleasa

    2016-01-01

    We determined the calorific value of white poplar (Populus alba L.) woody biomass to use it as fire-wood. The value of 19.133 MJ kg-1 obtained experimen-tally shows that the white poplar can be quite successfully used as firewood. Being of a lower quality in comparison with usual beech firewood, the white poplar has similar calorific value. The white poplar has a calorific density of 30.7%lower than that of current firewood. That is why the price of this firewood from white poplar is lower accord-ingly. Also, the prognosis of calorific value on the basis of the main chemical elements, being very close to the experimental value (?2.6%), indicates an appropriate value can be achieved to be used for investigation with the chemical element analysis.

  2. Feeding performance of Clostera fulgurita on three clones of Populus deltoides

    Institute of Scientific and Technical Information of China (English)

    K.S.Sangha

    2011-01-01

    Poplar leaf defoliator, Closterafulgurita (Walker) larvae were reared on three Populus deltoides clones (PLI, PL5 and PL7) in the laboratory. The nutritional indices were computed for working out the relationship between food consumption and growth rate of 3rd, 4th and 5th instar larvae on three clones. The result showed that the consumption index (CI), approximate digestibility (AD), growth rate (GR), relative growth rate (RGR) and efficiency of conversion of ingested food (ECl)decreased with the increase in the age of the larvae. Efficiency of conversion of digested food (ECD) increased with increase in age of the larvae. GR and RGR varied significantly, indicating that larval development was enhanced on PLI as compared to PL5 & PL7. The values of AD, ECl and ECD were not affected by the different clones. Feeding and growth indices could be useful to define a defoliation prediction model.

  3. Structural Characteristics and Eco-adaptability of Heteromorphic Leaves of Populus euphratica

    Institute of Scientific and Technical Information of China (English)

    Li Zhao-xia; Zheng Cai-xia

    2005-01-01

    The microstructural and ultrastructural traits of three kinds of typical leaves of Populus euphratica Olive, including lanceolate, broad-ovate and dentate broad-ovate leaves, were studied by using electron microscope and optical microscope. The results showed that with the leaves changing from lanceolate shape to dentate broad-ovate shape, their structure obviously tended to be xeromorph: developed palisade tissue, undeveloped spongy tissue, thick cutin layer and sunken stomas. The amount of mitochondria tended to be increased, and the shape of chloroplasts varied from regular spindle to irregular rotundity or oval. The leaves were covered with wax without cilium, and the stomas on the upper and lower epidermis of the leaves opened unevenly. The stomas on the lower epidermis were deeper than those on the upper epidermis under the scanning electron microscope. The results implied that the structural characteristics of the diversiform-leaves of P. euphratica are related to its eco-adaptability.

  4. Stomata morphological traits in two different genotypes of Populus nigra L.

    Directory of Open Access Journals (Sweden)

    Russo G

    2015-08-01

    Full Text Available Populus nigra L. (black poplar possesses amphistomatic leaves, with large (giant and normal sized stomata. The role of giant stomata in leaf development, and the consequences on stomatal density in adult leaves remains elusive. This paper describes the characteristics of ordinary and giant stomata in leaves of two black poplar genotypes (58-861 with large leaves from northern Italy, and Poli with small leaves from southern Italy. Stomatal traits in both genotypes were studied using light microscopy on mature leaf adaxial and abaxial epidermal impressions. Moreover, scanning electron microscopy was applied to study giant and normal stomata in early, young, and mature leaves. Leaf abaxial surfaces in the two genotypes revealed variable sizes and patterns of stomata related to differences in intrinsic water use efficiency (Wi. These observations provided evidence of different stomatal types in mature black poplar leaves, and new information regarding the presence and potential role of giant stomata in black poplar leaves.

  5. Genotypic variation in a foundation tree (Populus tremula L.) explains community structure of associated epiphytes.

    Science.gov (United States)

    Davies, Chantel; Ellis, Christopher J; Iason, Glenn R; Ennos, Richard A

    2014-01-01

    Community genetics hypothesizes that within a foundation species, the genotype of an individual significantly influences the assemblage of dependent organisms. To assess whether these intra-specific genetic effects are ecologically important, it is required to compare their impact on dependent organisms with that attributable to environmental variation experienced over relevant spatial scales. We assessed bark epiphytes on 27 aspen (Populus tremula L.) genotypes grown in a randomized experimental array at two contrasting sites spanning the environmental conditions from which the aspen genotypes were collected. We found that variation in aspen genotype significantly influenced bark epiphyte community composition, and to the same degree as environmental variation between the test sites. We conclude that maintaining genotypic diversity of foundation species may be crucial for conservation of associated biodiversity.

  6. In-situ reduced silver nanoparticles on populus fiber and the catalytic application

    Science.gov (United States)

    Li, Miaomiao; Gong, Yumei; Wang, Wenheng; Xu, Guangpeng; Liu, Yuanfa; Guo, Jing

    2017-02-01

    One kind of composites involved in silver nanoparticles (AgNPs) loading in-situ on natural populus fiber (PF) matrix was prepared by polyamidoxime (PAO) functionalized the cellulose fiber. In which PAO worked as trapping and stabilizing agents chelating silver ions and made it reduced in-situ to obtain AgNPs by borohydride at room temperature. The synthesized composites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Moreover, the composites showed significant catalytic activity 1.87 s-1 g-1 and repeated usability more than 7 cycles in reducing 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) detected by UV-vis spectrophotometer in aqueous solution due to the surface-enhanced immobility and large amount of AgNPs. The natural cellulose fiber provides a green platform to react and support other noble metals for wide catalytic reactions.

  7. Genome-wide transcriptional profiling reveals molecular signatures of secondary xylem differentiation in Populus tomentosa.

    Science.gov (United States)

    Yang, X H; Li, X G; Li, B L; Zhang, D Q

    2014-11-11

    Wood formation occurs via cell division, primary cell wall and secondary wall formation, and programmed cell death in the vascular cambium. Transcriptional profiling of secondary xylem differentiation is essential for understanding the molecular mechanisms underlying wood formation. Differential gene expression in secondary xylem differentiation of Populus has been previously investigated using cDNA microarray analysis. However, little is known about the molecular mechanisms from a genome-wide perspective. In this study, the Affymetrix poplar genome chips containing 61,413 probes were used to investigate the changes in the transcriptome during secondary xylem differentiation in Chinese white poplar (Populus tomentosa). Two xylem tissues (newly formed and lignified) were sampled for genome-wide transcriptional profiling. In total, 6843 genes (~11%) were identified with differential expression in the two xylem tissues. Many genes involved in cell division, primary wall modification, and cellulose synthesis were preferentially expressed in the newly formed xylem. In contrast, many genes, including 4-coumarate:cinnamate-4-hydroxylase (C4H), 4-coumarate:CoA ligase (4CL), cinnamyl alcohol dehydrogenase (CAD), and caffeoyl CoA 3-O-methyltransferase (CCoAOMT), associated with lignin biosynthesis were more transcribed in the lignified xylem. The two xylem tissues also showed differential expression of genes related to various hormones; thus, the secondary xylem differentiation could be regulated by hormone signaling. Furthermore, many transcription factor genes were preferentially expressed in the lignified xylem, suggesting that wood lignification involves extensive transcription regulation. The genome-wide transcriptional profiling of secondary xylem differentiation could provide additional insights into the molecular basis of wood formation in poplar species.

  8. DNA damage in Populus tremuloides clones exposed to elevated O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Tai, Helen H., E-mail: helen.tai@agr.gc.c [Agriculture and Agri-Food Canada, Potato Research Centre, P.O. Box 20280, Fredericton, New Brunswick, E3B 4Z7 (Canada); Natural Resources Canada, Canadian Forest Service - Atlantic Forestry Centre, 1350 Regent Street S., Fredericton, New Brunswick, E3B 5P7 (Canada); Percy, Kevin E. [Natural Resources Canada, Canadian Forest Service - Atlantic Forestry Centre, 1350 Regent Street S., Fredericton, New Brunswick, E3B 5P7 (Canada); Karnosky, David F. [School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI 49931 (United States)

    2010-04-15

    The effects of elevated concentrations of atmospheric tropospheric ozone (O{sub 3}) on DNA damage in five trembling aspen (Populus tremuloides Michx.) clones growing in a free-air enrichment experiment in the presence and absence of elevated concentrations of carbon dioxide (CO{sub 2}) were examined. Growing season mean hourly O{sub 3} concentrations were 36.3 and 47.3 ppb for ambient and elevated O{sub 3} plots, respectively. The 4th highest daily maximum 8-h ambient and elevated O{sub 3} concentrations were 79 and 89 ppb, respectively. Elevated CO{sub 2} averaged 524 ppm (+150 ppm) over the growing season. Exposure to O{sub 3} and CO{sub 2} in combination with O{sub 3} increased DNA damage levels above background as measured by the comet assay. Ozone-tolerant clones 271 and 8L showed the highest levels of DNA damage under elevated O{sub 3} compared with ambient air; whereas less tolerant clone 216 and sensitive clones 42E and 259 had comparably lower levels of DNA damage with no significant differences between elevated O{sub 3} and ambient air. Clone 8L was demonstrated to have the highest level of excision DNA repair. In addition, clone 271 had the highest level of oxidative damage as measured by lipid peroxidation. The results suggest that variation in cellular responses to DNA damage between aspen clones may contribute to O{sub 3} tolerance or sensitivity. - Ozone tolerant clones and sensitive Populus tremuloides clones show differences in DNA damage and repair.

  9. Untangling the effects of root age and tissue nitrogen on root respiration in Populus tremuloides at different nitrogen supply.

    Science.gov (United States)

    Ceccon, Christian; Tagliavini, Massimo; Schmitt, Armin Otto; Eissenstat, David M

    2016-05-01

    Root respiration is a major contributor to terrestrial carbon flux. Many studies have shown root respiration to increase with an increase in root tissue nitrogen (N) concentration across species and study sites. Studies have also shown that both root respiration and root N concentration typically decrease with root age. The effects of added N may directly increase respiration of existing roots or may affect respiration by shifting the age structure of a root population by stimulating growth. To the best of our knowledge, no study has ever examined the effect of added N as a function of root age on root respiration. In this study, root respiration of 13-year-old Populus tremuloides Michx. trees grown in the field and 1-year-old P. tremuloides seedlings grown in containers was analyzed for the relative influence of root age and root N concentration independent of root age on root respiration. Field roots were first tracked using root windows and then sampled at known age. Nitrogen was either applied or not to small patches beneath the windows. In a pot experiment, each plant was grown with its root system split between two separate pots and N was applied at three different levels, either at the same or at different rates between pots. Root N concentration ranged between 1.4 and 1.7% in the field experiment and 1.8 and 2.6% in the seedling experiment. We found that addition of N increased root N concentration of only older roots in the field but of roots of all ages in the potted seedlings. In both experiments, the age-dependent decline in root respiration was largely consistent, and could be explained by a negative power function. Respiration decreased ∼50% by 3 weeks of age. Although root age was the dominant factor affecting respiration in both experiments, in the field experiment, root N also contributed to root respiration independent of root age. These results add further insight into respiratory responses of roots to N addition and mechanisms underlying the

  10. Characterization of PM2.5-bound polycyclic aromatic hydrocarbons and its deposition in Populus tomentosa leaves in Beijing.

    Science.gov (United States)

    An, Hailong; Zhang, Gang; Liu, Chao; Guo, Huihong; Yin, Weilun; Xia, Xinli

    2017-03-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous constituents of air particulate matter and can be taken up by plants from the atmosphere. However, the purification of particulate-bound PAHs in the atmosphere by greening tree species has not been reported. In this study, we assess the concentrations, distribution, and sources of PM2.5-bound PAHs at three representative sites of Beijing in April, July, and November (non-heating period) and analyze the correlation between PAHs in Populus tomentosa leaves and in atmospheric PM2.5. The total PAH concentrations in PM2.5 were in the range of 19.85 ± 13.59-42.01 ± 37.17 ng/m(3) with mean value of 31.35 ng/m(3) at the three sites, and the PM2.5-bound PAHs concentrations in the two suburban sites (YF and YQ) were significantly higher than that in urban site (XZM) in November (autumn). At the three sites, the high molecular weight (HMW) PAHs in PM2.5 were dominant, accounting for 54.09-64.90% of total PAHs and the concentration of HMW PAHs was, on average, 9.1 times higher than that of low molecular weight (LWM) PAHs. Principal component analysis combined with diagnostic ratio analysis indicated that vehicle emission, wood combustion, and industrial processes were the main sources for PM2.5-bound PAHs in the non-heating period of Beijing. However, the LMW PAHs were dominant in P. tomentosa leaves. The concentrations of HMW PAHs (BbF, BkF, BaP, IcdP, and BghiP) in P. tomentosa leaves reached 26.11 ± 2.39, 41.42 ± 7.77, and 55.70 ± 12.33 ng/g at YQ, XZM, and YF in autumn, respectively, and were, on average, 2.1 times higher than those in April (spring) at the three sites. The ∑5PAHs concentration in P. tomentosa leaves accumulatively increased from spring to autumn, which was not related to the temporal variation of PM2.5-bound PAHs. Nevertheless, the ∑5PAHs mean concentrations followed the order of YF > XZM > YQ. This trend was consistent with spatial distribution of atmosphere PM2.5, indicating

  11. [Effects of fertilization method and nitrogen application rate on soil nitrogen vertical migration in a Populus xeuramericana cv. 'Guariento' plantation].

    Science.gov (United States)

    Dai, Teng-fei; Xi, Ben-ye; Yan, Xiao-li; Jia, Li-ming

    2015-06-01

    A field experiment was conducted to investigate the effects of fertilization methods, i.e., drip (DF) and furrow fertilization (GF), and nitrogen (N) application rates (25, 50, 75 g N · plant(-1) · time(-1)) on the dynamics of soil N vertical migration in a Populus x euramericana cv. 'Guariento' plantation. The results showed that soil NH4(+)-N and NO3(-)-N contents decreased with the increasing soil depth under different fertilization methods and N application rates. In the DF treatment, soil NH4(+)-N and NO3(-)-N were mainly concentrated in the 0-40 cm soil layer, and their contents ascended firstly and then descended, reaching their maximum values at the 5th day (211.1 mg · kg(-1)) and 10th day (128.8 mg · kg(-1)) after fertilization, respectively. In the GF treatment, soil NH4(+)-N and NO3(-)-N were mainly concentrated in the 0-20 cm layer, and the content of soil NO3(-)-N rose gradually and reached its maximum at the 20th day (175.7 mg · kg(-1)) after fertilization, while the NH4(+)-N content did not change significantly after fertilization. Overall, N fertilizer had an effect within 20 days in the DF treatment, and more than 20 days in the GF treatment. In the DF treatment, the content and migration depth of soil NH4(+)-N and NO3(-)-N increased with the N application rate. In the GF treatment, the NO3(-)-N content increased with the N application rate, but the NH4(+)-N content was not influenced. Under the DF treatment, the hydrolysis rate, nitrification rate and migration depth of urea were higher or larger than that under the GF treatment, and more N accumulated in deep soil as the N application rate increased. Considering the distribution characteristics of fine roots and soil N, DF would be a better fertilization method in P. xeuramericana cv. 'Guariento' plantation, since it could supply N to larger distribution area of fine roots. When the N application rate was 50 g · tree(-1) each time, nitrogen mainly distributed in the zone of fine roots and

  12. Germination and establishment of the native plains cottonwood (Populus deltoides Marshall subsp. monilifera) and the exotic Russian-olive (Elaeagnus angustifolia L.)

    Science.gov (United States)

    Shafroth, Patrick B.; Auble, Gregor T.; Scott, Michael L.

    1995-01-01

    Russian-olive (Elaeagnus angustifolia) is a small Eurasian tree that has escaped from cultivation and become naturalized, primarily along watercourses throughout the western United States. We examined germination and establishment of Russian-olive and plains cottonwood (Populus deltoides), the principal native riparian tree of the Great Plains, under a range of experimental moisture and light conditions. The fewest seedings established under the driest conditions; seedling biomass was predictably lower in the shade; root-to-shoot ratios were higher for cottonwood, higher in the sun, and higher under drier conditions. Several interactions were also significant. The timing of germination and mortality varied between plains cottonwood and Russian-olive: cottonwood germinated in mid-June in all treatments in a single pulse with subsequent mortality; the timing and amount of Russian-olive germination differed substantially across treatments with little net mortality. Differences in life-history traits of these species, including seed size, viability, and dispersal, help explain treatment differences. Russian-olive will likely remain an important component of riparian communities along both unregulated and regulated western rivers because it succeeds under conditions optimal for cottonwood establishment and under many conditions unfavorable for cottonwood. Furthermore, many western states still encourage planting of Russian-olive, and control techniques tend to be labor-intensive and expensive.

  13. Modelagem da estrutura de florestas clonais de Populus deltoides Marsh através de distribuições diamétricas probabilísticas

    Directory of Open Access Journals (Sweden)

    Julio Eduardo Arce

    2004-01-01

    Full Text Available In this paper, six Populus deltoides Marsh. clonal forests planted in 1986 were structurally evaluated between 1987 and 1995 (1 to 9 years old. Probabilistic functions normal, gamma, beta, Johnson SB and Weibull with two and three parameters were fitted to the observed diametric distributions data, by means of, depending on the case, the Moments Method, the Maximum Likelihood Method, the methodology proposed by Loetsch et al. (1973 and the mean and standard deviations to estimate the corresponding parameters. Goodness of fit was evaluated considering the relative deviations between the observed and predicted diameters sum raised to the first, second, third and fourth power. For all analyzed functions, deviations increased with the power increment, and the Weibull distribution with two parameters (a = 0 presented the smaller values for all the observed years considering diameters raised to the fourth power. Values of relative deviations between observed and predicted diameter sums raised to the fourth power were lesser than 0.005 (0.5% for the Weibull function with two parameters, excepting the first year, in which all functions presented higher deviation values (between 11% and 13%. Weibull scale (b and shape (c parameters were estimated through linear regression fitted equations using the stand quadratic mean diameter as independent variable.

  14. Responses of leaf nitrogen concentration and leaf area of Populus sibirica seedlings to nitrogen fertilization in a semi-arid area, Mongolia

    Science.gov (United States)

    Chang, H.; Han, S. H.; Son, Y.

    2016-12-01

    We investigate the effects of three rates of nitrogen fertilization on Populus sibirica seedlings in a semi-arid area, Elsentasarkhai, Mongolia. In May 2015, 2-year-old P. sibirica seedlings were planted in the control and three fertilized plots. Urea was applied to each seedling with 5 g (N1), 15 g (N2) and 30 g (N3) in May 2015 and 2016. Leaf nitrogen concentration, total chlorophyll content, leaf area and specific leaf area (SLA) were measured in July 2016 and the differences were analyzed using one-way ANOVA (PSLA, however, leaf area in the N2 plot (3109.9 cm2) was significantly higher than that in the control (494.0 cm2). The N3 treatment significantly increased leaf nitrogen concentration and total chlorophyll content, however, it did not change leaf area. The N2 treatment seems to be suitable for leaf growth of P. sibirica seedlings in the study site. To determine the optimal rate of nitrogen fertilization, the growth and biomass of seedlings after treatments also need to be examined. * This study was supported by Korea Forest Service (S211216L030120).

  15. Populus balsamifera Extract and Its Active Component Salicortin Reduce Obesity and Attenuate Insulin Resistance in a Diet-Induced Obese Mouse Model

    Directory of Open Access Journals (Sweden)

    Despina Harbilas

    2013-01-01

    Full Text Available Populus balsamifera L. (BP is a medicinal plant stemming from the traditional pharmacopoeia of the Cree of Eeyou Istchee (CEI—Northern Quebec. In vitro screening studies revealed that it strongly inhibited adipogenesis in 3T3-L1 adipocytes, suggesting potential antiobesity activity. Salicortin was identified, through bioassay-guided fractionation, as the active component responsible for BP’s activity. The present study aimed to assess the potential of BP and salicortin at reducing obesity and features of the metabolic syndrome, in diet-induced obese C57Bl/6 mice. Mice were subjected to high fat diet (HFD for sixteen weeks, with BP (125 or 250 mg/kg or salicortin (12.5 mg/kg introduced in the HFD for the last eight of the sixteen weeks. BP and salicortin effectively reduced whole body and retroperitoneal fat pad weights, as well as hepatic triglyceride accumulation. Glycemia, insulinemia, leptin, and adiponectin levels were also improved. This was accompanied by a small yet significant reduction in food intake in animals treated with BP. BP and salicortin (slightly also modulated key components in signaling pathways involved with glucose regulation and lipid oxidation in the liver, muscle, and adipose tissue. These results confirm the validity of the CEI pharmacopoeia as alternative and complementary antiobesity and antidiabetic therapies.

  16. Determination of Fe, Hg, Mn, and Pb in three-rings of poplar (Populus alba L.) by U-shaped DC arc

    Science.gov (United States)

    Marković, D. M.; Novović, I.; Vilotić, D.; Ignjatović, Lj.

    2007-09-01

    The U-shaped DC arc with aerosol supply was applied for the determination of Fe, Hg, Mn, and Pb in poplar (Populus alba L.) tree-rings. By optimization of the operating parameters and by selection of the most appropriate signal integration time (20 s for Fe, Mn, and Pb and 30 s for Hg), the obtained limits of detection for Fe, Hg, Mn, and Pb are 5.8, 2.6, 1.6, and 2.0 ng/ml, respectively. The detection limits achieved by this method for Fe, Hg, Mn, and Pb are comparable with the detection limits obtained for these elements by such methods as inductively coupled plasma-atomic emission spectrometry (ICP-AES), direct coupled plasmatomic emission spectrometry (DCP-AES), and microwave-induced plasma-atomic emission spectrometry (MIP-AES). We used the tree-rings of poplar from two different locations. The first one is in the area close to the power plant “Nikola Tesla” TENT A, Obrenovac, while the other one is in the urban area of Novi Sad. In almost all cases, samples from the location at Obrenovac registered elevated average concentrations of Fe, Hg, Mn, and Pb in the tree-rings of poplar.

  17. The influence of liming on soil chemical properties and on the alleviation of manganese and copper toxicity in Juglans regia, Robinia pseudoacacia, Eucalyptus sp. and Populus sp. plantations.

    Science.gov (United States)

    Chatzistathis, T; Alifragis, D; Papaioannou, A

    2015-03-01

    Juglans regia, Robinia pseudoacacia, Eucalyptus sp. and Populus sp. plantations, suffering from Mn and Cu toxicity, were limed in order to reduce Cu and Mn solubility in soil. The purposes of the present work were: i) to study the changes in soil chemical properties after the addition of CaCO3, ii) to investigate the influence of liming on the reduction of Mn and Cu toxicity. After the addition of CaCO3 (three applications, during three successive years), pH and CaCO3 content were significantly increased, while organic C and N were significantly reduced. Exchangeable Ca concentrations have been slightly, or significantly, increased, while those of Mg have been decreased; in addition, ratios Ca/Mg and C/N have been significantly increased after liming. Impressive reductions of DTPA extractable Cu and Mn concentrations (more than 10 times in most cases) were recorded. It was also found that trees without Mn and Cu toxicity symptoms (healthy tress) before liming did not have, in many cases, significantly greater leaf Mn, Cu and Fe concentrations, than trees after soil liming (all the trees were healthy). This probably happened because excess Mn and Cu quantities had been accumulated into their root system. Finally, leaf Mn, Cu and Zn concentrations of trees suffering from toxicity were significantly decreased after soil liming, while leaf Fe concentrations, in all the plant species studied, were increased.

  18. Primary study on compression technology in wood of Populus tomentosa%毛白杨速生材压缩密实化工艺初步研究

    Institute of Scientific and Technical Information of China (English)

    寇建良; 孙照斌; 刘宇化

    2009-01-01

    以河北平原地区普遍种植的速生毛白杨木材为对象,通过压缩密化处理,测定素材和处理材的物理力学等性能,分析各因素对回复率的影响,寻找压缩密化的较优工艺条件.结果表明:饱水试件进行微波软化处理后,热压温度180℃左右、热压时间2.5 h、压缩量为50%时所得试件性能较好.%In this study, the technology experiment of compression wood of fast- growing Populus tomentosa, which is widespread planted in Hebei province, was carried out, and the properties of compressed wood were tested. The result showed: when wood was soft with the microwave after saturated by water before hot pressed, the temperature is about 180 ℃, the presses time is 2 h, and compressing ratio was 50% or so, the properties of compression wood was better than untreated wood.

  19. Effects of Simulated Nitrogen Deposition on Soil Respiration in a Populus euphratica Community in the Ebinur Lake Area, a Desert Ecosystem of Northwestern China.

    Science.gov (United States)

    He, Xuemin; Lv, Guanghui; Qin, Lu; Chang, Shunli; Yang, Min; Yang, Jianjun; Yang, Xiaodong

    2015-01-01

    One of the primary limiting factors for biological activities in desert ecosystems is nitrogen (N). This study therefore examined the effects of N and investigated the responses of an arid ecosystem to global change. We selected the typical desert plant Populus euphratica in a desert ecosystem in the Ebinur Lake area to evaluate the effects of N deposition on desert soil respiration. Three levels of N deposition (0, 37.5 and 112.5 kg·N·ha-1·yr-1) were randomly artificially provided to simulate natural N deposition. Changes in the soil respiration rates were measured from July to September in both 2010 and 2013, after N deposition in April 2010. The different levels of N deposition affected the total soil N, soil organic matter, soil C/N ratio, microorganism number, and microbial community structure and function. However, variable effects were observed over time in relation to changes in the magnitude of N deposition. Simulated high N deposition significantly reduced the soil respiration rate by approximately 23.6±2.5% (Psoil respiration rate by approximately 66.7±2.7% (Psoil moisture, whereas N deposition significantly increased the soil temperature in the 0-5 cm layer (Psoil respiration rate by altering soil properties.

  20. Pseudomonas aeruginosa Biofilm Formation and Persistence, along with the Production of Quorum Sensing-Dependent Virulence Factors, Are Disrupted by a Triterpenoid Coumarate Ester Isolated from Dalbergia trichocarpa, a Tropical Legume

    Science.gov (United States)

    Pottier, Laurent; Huet, Joelle; Rabemanantsoa, Christian; Kiendrebeogo, Martin; Andriantsimahavandy, Abel; Rasamindrakotroka, Andry; Stévigny, Caroline; Duez, Pierre; El Jaziri, Mondher

    2015-01-01

    Recently, extracts of Dalbergia trichocarpa bark have been shown to disrupt P. aeruginosa PAO1 quorum sensing (QS) mechanisms, which are key regulators of virulence factor expression and implicated in biofilm formation. One of the active compounds has been isolated and identified as oleanolic aldehyde coumarate (OALC), a novel bioactive compound that inhibits the formation of P. aeruginosa PAO1 biofilm and its maintenance as well as the expression of the las and rhl QS systems. Consequently, the production of QS-controlled virulence factors including, rhamnolipids, pyocyanin, elastase and extracellular polysaccharides as well as twitching and swarming motilities is reduced. Native acylhomoserine lactones (AHLs) production is inhibited by OALC but exogenous supply of AHLs does not restore the production of virulence factors by OALC-treated cultures, indicating that OALC exerts its effect beyond AHLs synthesis in the QS pathways. Further experiments provided a significant inhibition of the global virulence factor activator gacA by OALC. OALC disorganizes established biofilm structure and improves the bactericidal activity of tobramycin against biofilm-encapsulated PAO1 cells. Finally, a significant reduction of Caenorhabditis elegans paralysis was recorded when the worms were infected with OALC-pre-treated P. aeruginosa. Taken together, these results show that triterpenoid coumarate esters are suitable chemical backbones to target P. aeruginosa virulence mechanisms. PMID:26186595

  1. Exotic woody plant invaders of the Transvaal

    Directory of Open Access Journals (Sweden)

    L. Henderson

    1984-12-01

    Full Text Available The frequency and abundance o ;f exotic, woody plant invaders were recorded in 60% of the quarter degree squares in the study area. Sixty-one invaders were encountered o f which the most important and aggressive were Acacia dealbaia, Populus spp.,  Melia azedarach, Opuntia ficus-indica, Salix babylonica and  Acacia mearnsii. Invasion patterns are discussed and an attempt is made to correlate distribution with environmental factors. Attention is drawn to the areas of greatest invasion and the areas that are liable to show the greatest expansion in the future.

  2. Metabolomics Reveals the Origins of Antimicrobial Plant Resins Collected by Honey Bees

    Science.gov (United States)

    Wilson, Michael B.; Spivak, Marla; Hegeman, Adrian D.; Rendahl, Aaron; Cohen, Jerry D.

    2013-01-01

    The deposition of antimicrobial plant resins in honey bee, Apis mellifera, nests has important physiological benefits. Resin foraging is difficult to approach experimentally because resin composition is highly variable among and between plant families, the environmental and plant-genotypic effects on resins are unknown, and resin foragers are relatively rare and often forage in unobservable tree canopies. Subsequently, little is known about the botanical origins of resins in many regions or the benefits of specific resins to bees. We used metabolomic methods as a type of environmental forensics to track individual resin forager behavior through comparisons of global resin metabolite patterns. The resin from the corbiculae of a single bee was sufficient to identify that resin's botanical source without prior knowledge of resin composition. Bees from our apiary discriminately foraged for resin from eastern cottonwood (Populus deltoides), and balsam poplar (P. balsamifera) among many available, even closely related, resinous plants. Cottonwood and balsam poplar resin composition did not show significant seasonal or regional changes in composition. Metabolomic analysis of resin from 6 North American Populus spp. and 5 hybrids revealed peaks characteristic to taxonomic nodes within Populus, while antimicrobial analysis revealed that resin from different species varied in inhibition of the bee bacterial pathogen, Paenibacillus larvae. We conclude that honey bees make discrete choices among many resinous plant species, even among closely related species. Bees also maintained fidelity to a single source during a foraging trip. Furthermore, the differential inhibition of P. larvae by Populus spp., thought to be preferential for resin collection in temperate regions, suggests that resins from closely related plant species many have different benefits to bees. PMID:24204850

  3. Metabolomics reveals the origins of antimicrobial plant resins collected by honey bees.

    Directory of Open Access Journals (Sweden)

    Michael B Wilson

    Full Text Available The deposition of antimicrobial plant resins in honey bee, Apis mellifera, nests has important physiological benefits. Resin foraging is difficult to approach experimentally because resin composition is highly variable among and between plant families, the environmental and plant-genotypic effects on resins are unknown, and resin foragers are relatively rare and often forage in unobservable tree canopies. Subsequently, little is known about the botanical origins of resins in many regions or the benefits of specific resins to bees. We used metabolomic methods as a type of environmental forensics to track individual resin forager behavior through comparisons of global resin metabolite patterns. The resin from the corbiculae of a single bee was sufficient to identify that resin's botanical source without prior knowledge of resin composition. Bees from our apiary discriminately foraged for resin from eastern cottonwood (Populus deltoides, and balsam poplar (P. balsamifera among many available, even closely related, resinous plants. Cottonwood and balsam poplar resin composition did not show significant seasonal or regional changes in composition. Metabolomic analysis of resin from 6 North American Populus spp. and 5 hybrids revealed peaks characteristic to taxonomic nodes within Populus, while antimicrobial analysis revealed that resin from different species varied in inhibition of the bee bacterial pathogen, Paenibacillus larvae. We conclude that honey bees make discrete choices among many resinous plant species, even among closely related species. Bees also maintained fidelity to a single source during a foraging trip. Furthermore, the differential inhibition of P. larvae by Populus spp., thought to be preferential for resin collection in temperate regions, suggests that resins from closely related plant species many have different benefits to bees.

  4. A method for describing the canopy architecture of coppice poplar with allometric relationships.

    Science.gov (United States)

    Casella, Eric; Sinoquet, Hervé

    2003-12-01

    A multi-scale biometric methodology for describing the architecture of fast-growing short-rotation woody crops is used to describe 2-year-old poplar clones during the second rotation. To allow for expressions of genetic variability observed within this species (i.e., growth potential, leaf morphology, coppice and canopy structure), the method has been applied to two clones: Ghoy (Gho) (Populus deltoides Bartr. ex Marsh. x Populus nigra L.) and Trichobel (Tri) (Populus trichocarpa Torr. & A. Gray x Populus trichocarpa). The method operates at the stool level and describes the plant as a collection of components (shoots and branches) described as a collection of metameric elements, themselves defined as a collection of elementary units (internode, petiole, leaf blade). Branching and connection between the plant units (i.e., plant topology) and their spatial location, orientation, size and shape (i.e., plant geometry) describe the plant architecture. The methodology has been used to describe the plant architecture of 15 selected stools per clone over a 5-month period. On individual stools, shoots have been selected from three classes (small, medium and large) spanning the diameter distribution range. Using a multi-scale approach, empirical allometric relationships were used to parameterize elementary units of the plant, topological relationships and geometry (e.g., distribution of shoot diameters on stool, shoot attributes from shoot diameter). The empirical functions form the basis of the 3-D Coppice Poplar Canopy Architecture model (3-D CPCA), which recreates the architecture and canopy structure of fast-growing coppice crops at the plot scale. Model outputs are assessed through visual and quantitative comparisons between actual photographs of the coppice canopy and simulated images. Overall, results indicate a good predictive ability of the 3-D CPCA model.

  5. Protein (Viridiplantae): 7789 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 3646:3627 3688:10495 ... 238069:10495 ... 3689:10495 ... 3694:10495 ... hypothetical protein POPTR_0015s11720g Populus trichocarpa MEGGNGNEV...EREEDDSVSDILQDRFRLSAISIAENEAKKNGVEISEPITSCIADLALNYTEQLAK

  6. Evaluation of the sap flow using heat pulse method to determine transpiration of the Populus euphratica canopy

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiaoyou; KANG Ersi; ZHOU Maoxian

    2007-01-01

    The sap flow of the sampled Populus euphratica stems at different radial depths and directions had been studied in Ejina Oasis,in the lower reaches of the Heihe River.Based on sap flow measurements,the transpiration of the entire canopy was calculated.Results showed a linear correlation between the sap flow and the sapwood area of the P.euphratica.Through the analysis of the diameter at breast height in the sample plot,it was found that the distribution of the diameters and the corresponding sapwood area was exponentially correlated,with the coefficient of correlation being 0.976,7.The calculated transpiration of the Populus euphratica canopy was 214.9 mm based on the specific conductivity method.

  7. Transcriptional profiling by cDNA-AFLP analysis showed differential transcript abundance in response to water stress in Populus hopeiensis

    OpenAIRE

    Song, Yuepeng; Wang, Zeliang; Bo, Wenhao; Ren, Yuanyuan; Zhang, Zhiyi; Zhang, Deqiang

    2012-01-01

    Background Drought is one of the main environmental factors limiting tree growth and productivity of plantation forests worldwide. Populus hopeiensis Hu et Chow is one of the most important commercial plantation tree species in China. However, the genes controlling drought tolerance in this species have not been identified or characterized. Here, we conducted differential expression analyses and identified a number of genes that were up- or downregulated in P. hopeiensis during water stress. ...

  8. RNA sequencing of Populus x canadensis roots identifies key molecular mechanisms underlying physiological adaption to excess zinc.

    Science.gov (United States)

    Ariani, Andrea; Di Baccio, Daniela; Romeo, Stefania; Lombardi, Lara; Andreucci, Andrea; Lux, Alexander; Horner, David Stephen; Sebastiani, Luca

    2015-01-01

    Populus x canadensis clone I-214 exhibits a general indicator phenotype in response to excess Zn, and a higher metal uptake in roots than in shoots with a reduced translocation to aerial parts under hydroponic conditions. This physiological adaptation seems mainly regulated by roots, although the molecular mechanisms that underlie these processes are still poorly understood. Here, differential expression analysis using RNA-sequencing technology was used to identify the molecular mechanisms involved in the response to excess Zn in root. In order to maximize specificity of detection of differentially expressed (DE) genes, we consider the intersection of genes identified by three distinct statistical approaches (61 up- and 19 down-regulated) and validate them by RT-qPCR, yielding an agreement of 93% between the two experimental techniques. Gene Ontology (GO) terms related to oxidation-reduction processes, transport and cellular iron ion homeostasis were enriched among DE genes, highlighting the importance of metal homeostasis in adaptation to excess Zn by P. x canadensis clone I-214. We identified the up-regulation of two Populus metal transporters (ZIP2 and NRAMP1) probably involved in metal uptake, and the down-regulation of a NAS4 gene involved in metal translocation. We identified also four Fe-homeostasis transcription factors (two bHLH38 genes, FIT and BTS) that were differentially expressed, probably for reducing Zn-induced Fe-deficiency. In particular, we suggest that the down-regulation of FIT transcription factor could be a mechanism to cope with Zn-induced Fe-deficiency in Populus. These results provide insight into the molecular mechanisms involved in adaption to excess Zn in Populus spp., but could also constitute a starting point for the identification and characterization of molecular markers or biotechnological targets for possible improvement of phytoremediation performances of poplar trees.

  9. RNA sequencing of Populus x canadensis roots identifies key molecular mechanisms underlying physiological adaption to excess zinc.

    Directory of Open Access Journals (Sweden)

    Andrea Ariani

    Full Text Available Populus x canadensis clone I-214 exhibits a general indicator phenotype in response to excess Zn, and a higher metal uptake in roots than in shoots with a reduced translocation to aerial parts under hydroponic conditions. This physiological adaptation seems mainly regulated by roots, although the molecular mechanisms that underlie these processes are still poorly understood. Here, differential expression analysis using RNA-sequencing technology was used to identify the molecular mechanisms involved in the response to excess Zn in root. In order to maximize specificity of detection of differentially expressed (DE genes, we consider the intersection of genes identified by three distinct statistical approaches (61 up- and 19 down-regulated and validate them by RT-qPCR, yielding an agreement of 93% between the two experimental techniques. Gene Ontology (GO terms related to oxidation-reduction processes, transport and cellular iron ion homeostasis were enriched among DE genes, highlighting the importance of metal homeostasis in adaptation to excess Zn by P. x canadensis clone I-214. We identified the up-regulation of two Populus metal transporters (ZIP2 and NRAMP1 probably involved in metal uptake, and the down-regulation of a NAS4 gene involved in metal translocation. We identified also four Fe-homeostasis transcription factors (two bHLH38 genes, FIT and BTS that were differentially expressed, probably for reducing Zn-induced Fe-deficiency. In particular, we suggest that the down-regulation of FIT transcription factor could be a mechanism to cope with Zn-induced Fe-deficiency in Populus. These results provide insight into the molecular mechanisms involved in adaption to excess Zn in Populus spp., but could also constitute a starting point for the identification and characterization of molecular markers or biotechnological targets for possible improvement of phytoremediation performances of poplar trees.

  10. Defining the Boundaries and Characterizing the Landscape of Genome Expression in Vascular Tissues of Populus using Shotgun Proteomics

    Energy Technology Data Exchange (ETDEWEB)

    Abraham, Paul E [ORNL; Adams, Rachel M [ORNL; Giannone, Richard J [ORNL; Kalluri, Udaya C [ORNL; Ranjan, Priya [ORNL; Erickson, Brian K [ORNL; Shah, Manesh B [ORNL; Tuskan, Gerald A [ORNL; Hettich, Robert {Bob} L [ORNL

    2012-01-01

    Current state-of-the-art experimental and computational proteomic approaches were integrated to obtain a comprehensive protein profile of Populus vascular tissue. This featured: 1) a large sample set consisting of two genotypes grown under normal and tension stress conditions, 2) bioinformatics clustering to effectively handle gene duplication, and 3) an informatics approach to track and identify single amino acid polymorphisms (SAAPs). By applying a clustering algorithm to the Populus database, the number of protein entries decreased from 64,689 proteins to a total of 43,069 protein groups, thereby reducing 7,505 identified proteins to a total of 4,226 protein groups, in which 2,016 were singletons. This reduction implies that ~50% of the measured proteins were clustered into groups that shared extensive sequence homology. Using conservative search criteria, we were able to identify 1,354 peptides containing a SAAP and 201 peptides that become tryptic due to a K or R substitution. These newly identified peptides correspond to 502 proteins, including 97 proteins that were not previously identified. In total, the integration of deep proteome measurements on an extensive sample set with protein clustering and peptide sequence variants provided an unprecedented level of proteome characterization for Populus, allowing us to spatially resolve the vascular tissue proteome.

  11. Changes in sulphur metabolism of grey poplar (Populus x canescens) leaves during salt stress: a metabolic link to photorespiration.

    Science.gov (United States)

    Herschbach, Cornelia; Teuber, Markus; Eiblmeier, Monika; Ehlting, Barbara; Ache, Peter; Polle, Andrea; Schnitzler, Jörg-Peter; Rennenberg, Heinz

    2010-09-01

    The poplar hybrid Populus x canescens (syn. Populus tremula x Populus alba) was subjected to salt stress by applying 75 mM NaCl for 2 weeks in hydroponic cultures. Decreasing maximum quantum yield (Fv/Fm) indicated damage of photosystem II (PS II), which was more pronounced under nitrate compared with ammonium nutrition. In vivo staining with diaminobenzidine showed no accumulation of H(2)O(2) in the leaf lamina; moreover, staining intensity even decreased. But at the leaf margins, development of necrotic tissue was associated with a strong accumulation of H(2)O(2). Glutathione (GSH) contents increased in response to NaCl stress in leaves but not in roots, the primary site of salt exposure. The increasing leaf GSH concentrations correlated with stress-induced decreases in transpiration and net CO(2) assimilation rates at light saturation. Enhanced rates of photorespiration could also be involved in preventing reactive oxygen species formation in chloroplasts and, thus, in protecting PS II from damage. Accumulation of Gly and Ser in leaves indeed indicates increasing rates of photorespiration. Since Ser and Gly are both immediate precursors of GSH that can limit GSH synthesis, it is concluded that the salt-induced accumulation of leaf GSH results from enhanced photorespiration and is thus probably restricted to the cytosol.

  12. Intraspecific variation in root and leaf traits and leaf-root trait linkages in eight aspen demes (Populus tremula and P. tremuloides).

    Science.gov (United States)

    Hajek, Peter; Hertel, Dietrich; Leuschner, Christoph

    2013-01-01

    Leaf and fine root morphology and physiology have been found to vary considerably among tree species, but not much is known about intraspecific variation in root traits and their relatedness to leaf traits. Various aspen progenies (Populus tremula and P. tremuloides) with different growth performance are used in short-rotation forestry. Hence, a better understanding of the link between root trait syndromes and the adaptation of a deme to a particular environment is essential in order to improve the match between planted varieties and their growth conditions. We examined the between-deme (genetic) and within-deme (mostly environmental) variation in important fine root traits [mean root diameter, specific root area (SRA) and specific root length (SRL), root tissue density (RTD), root tip abundance, root N concentration] and their co-variation with leaf traits [specific leaf area (SLA), leaf size, leaf N concentration] in eight genetically distinct P. tremula and P. tremuloides demes. Five of the six root traits varied significantly between the demes with largest genotypic variation in root tip abundance and lowest in mean root diameter and RTD (no significant difference). Within-deme variation in root morphology was as large as between-deme variation suggesting a relatively low genetic control. Significant relationships existed neither between SLA and SRA nor between leaf N and root N concentration in a plant. Contrary to expectation, high aboveground relative growth rates (RGR) were associated with large, and not small, fine root diameters with low SRA and SRL. Compared to leaf traits, the influence of root traits on RGR was generally low. We conclude that aspen exhibits large intraspecific variation in leaf and also in root morphological traits which is only partly explained by genetic distances. A root order-related analysis might give deeper insights into intraspecific root trait variation.

  13. Auxin-responsive DR5 promoter coupled with transport assays suggest separate but linked routes of auxin transport during woody stem development in Populus.

    Science.gov (United States)

    Spicer, Rachel; Tisdale-Orr, Tracy; Talavera, Christian

    2013-01-01

    Polar auxin transport (PAT) is a major determinant of plant morphology and internal anatomy with important roles in vascular patterning, tropic growth responses, apical dominance and phyllotactic arrangement. Woody plants present a highly complex system of vascular development in which isolated bundles of xylem and phloem gradually unite to form concentric rings of conductive tissue. We generated several transgenic lines of hybrid poplar (Populus tremula x alba) with the auxin-responsive DR5 promoter driving GUS expression in order to visualize an auxin response during the establishment of secondary growth. Distinct GUS expression in the cambial zone and developing xylem-side derivatives supports the current view of this tissue as a major stream of basipetal PAT. However, we also found novel sites of GUS expression in the primary xylem parenchyma lining the outer perimeter of the pith. Strands of primary xylem parenchyma depart the stem as a leaf trace, and showed GUS expression as long as the leaves to which they were connected remained attached (i.e., until just prior to leaf abscission). Tissue composed of primary xylem parenchyma strands contained measurable levels of free indole-3-acetic acid (IAA) and showed basipetal transport of radiolabeled auxin ((3)H-IAA) that was both significantly faster than diffusion and highly sensitive to the PAT inhibitor NPA. Radiolabeled auxin was also able to move between the primary xylem parenchyma in the interior of the stem and the basipetal stream in the cambial zone, an exchange that was likely mediated by ray parenchyma cells. Our results suggest that (a) channeling of leaf-derived IAA first delineates isolated strands of pre-procambial tissue but then later shifts to include basipetal transport through the rapidly expanding xylem elements, and (b) the transition from primary to secondary vascular development is gradual, with an auxin response preceding the appearance of a unified and radially-organized vascular cambium.

  14. Management of Animal Carcass Disposal Sites Using a Biochar Permeable Reactive Barrier and Fast Growth Tree (Populus euramericana: A Field Study in Korea

    Directory of Open Access Journals (Sweden)

    Jung-Hwan Yoon

    2017-03-01

    Full Text Available Among many disposal options of animal carcasses due to animal diseases including foot-and-mouth disease (FMD and avian influenza (AI, on-farm burial has been the most frequently used one in Korea. Animal carcasses generate contaminants such as ammonium-N and chloride. This study aimed at testing biochar (BC as a permeable reactive barrier (PRB material in combination with fast growing tree species (Populus euramericana to mitigate groundwater pollution from animal burial sites. For this, a PRB filled with BC was installed and 400 poplar tree (P. euramericana seedlings were planted. Tested BC was obtained from rice husk and its efficiency to mitigate contaminant migration from a burial site of pig carcasses was tested using ammonium-N, chloride, electrical conductivity (EC, and pH as monitoring parameters. Monitoring wells downstream from the burial site were used. Leachates from a monitoring well, three wells inside the burial site close to PRB and three wells outside the burial site close to PRB were sampled and analyzed for ammonium-N, Cl−, EC, and pH for four years from PRB installation. The pH, EC, and ammonium-N of leachate fluctuated during the test period depending on precipitation. pH, EC, and ammonium-N of the leachate samples collected from outside of the burial site close to PRB decreased compared to those from inside of the burial site close to PRB. The concentrations of ammonium-N in the leachate from the monitoring well kept under the threshold value of 10 mg·L−1 for two years from PRB construction. In addition, the growth of poplar plants appeared to be increased via uptaking available N and P released from the burial sites. Achieved results suggest that BC PRBs can be used to in situ mitigate contaminant release from buried animal carcasses.

  15. Total Content of Polyphenols and Antioxidant Activity of Different Melliferous Plants

    Directory of Open Access Journals (Sweden)

    Claudia Pasca

    2016-01-01

    Full Text Available In this study polyphenols content and antioxidant activity of melliferous plants for the following: mint (Mentha pulegium, burdock (Arctium lappa, comfrey (Symphytum officinale, plantain (Pantago lanceolata, thyme (Thymus vulgaris, sage (Salvia officinalis, marigold (Calendula officinalis, small marshmallow (Althaea officinalis, echinacea (Echinaceea angustifolia and black popular (Populus nigra were investigated, using two different extraction methods. High content of polyphenols and flavones were extracted from Populus nigra, with an average of both extractions 23.14 mg GAE/g and 78.07 mg QE/g flavones. Among the studied plants, Arctium lappa registered the highest antioxidant activity (0.129 mmol Trolox/mL in alcoholic extract and Echinaceea angustifolia with a value of 0.122 mmol Trolox/mL in aqueous extract. The lowest values were recorded for the antioxidant activity of Althaea officinalis (alcoholic extract and Arctium lappa (aqueous extract. The results show that Arctium lappa, Echinaceea angustifolia and Populus nigra can be considered melliferous plants for their high biologically active compounds potential and bee products (honey and pollen that having the composition of these plants will have high antioxidant and antibacterial properties.

  16. The applications of populus fiber in removal of Cr{sup (VI)} from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Li, Miaomiao; Gong, Yumei, E-mail: ymgong@dlpu.edu.cn; Lyu, Aichao; Liu, Yuanfa, E-mail: morning309@126.com; Zhang, Hong, E-mail: zhang_hong1234@sina.com

    2016-10-15

    Highlights: • A sorbent for heavy metal ions based on populus fibers is prepared by a green way. • The chromium adsorption on the sorbent accords with the pseudo-second-order kinetics. • The proposed adsorption involves static attraction and chelation by the sorbent on chromium. • The sorbent is expected to be applied in universal conditions. - Abstract: The surface modification of natural materials to be applied in removal of Cr{sup (VI)} from aqueous solutions has attracted much attention. A natural sorbent for Cr{sup (VI)} based on natural populus fibers (PF) is prepared by transforming the cyano groups (AN) in polyacrylonitriles (PAN) grafted from PF into amidoxime groups (AO), which has strong ability to attract and chelate heavy metal ions. The prepared sorbent is characterized by Fourier Transform Infrared Spectra (FT-IR), thermogravimetric analysis (TGA), solid-state nuclear magnetic resonance ({sup 13}C NMR) and scanning electron microscope (SEM). As potassium dichromate solution (K{sub 2}Cr{sub 2}O{sub 7}) is used as a target solution for detecting adsorption capacity of the sorbent, the adsorption kinetics of the sorbent for chromiun is consistent with the pseudo-second-order kinetic model by analyzing the adsorption amount as a function of the sorbent dispersed duration in solution at pH = 2. The expected adsorption mechanism is that the Cr{sup (VI)} in anionic ions Cr{sub 2}O{sub 7}{sup 2−} and HCrO{sub 4}{sup −} are adsorbed through electrostatic attraction but when Cr{sup (VI)} is reduced to Cr{sup (III)} by AO, the electronegative nitrogen and oxygen in AO chelate it through coordination bond. The as-prepared PF derivant with high adsorption efficiency of chromium 180.5 mg/g (3.47 mmol/g), low cost, reusability and greenly preparation process suggests that the development of natural PF as a sorbent in removal of Cr{sup (VI)} from aqueous solutions is a destined significant approach.

  17. Incremento volumétrico de un ensayo con híbridos de Populus spp.

    Directory of Open Access Journals (Sweden)

    Oscar Vallejos-Barra

    2015-09-01

    Full Text Available El aumento de los requerimientos energéticos demandados por la sociedad ha impulsado el interés por establecer ensayos para seleccionar especies o híbridos que en el menor tiempo posible generen la mayor cantidad de volumen o biomasa. En esta investigación, se determinó el incremento medio anual del volumen de un ensayo con híbridos de Populus con la finalidad de dar a conocer la potencialidad de los híbridos del catálogo del Centro Tecnológico del Álamo (CTA de la Universidad de Talca. De este catálogo se escogieron los seis híbridos más promisorios y se compararon con seis híbridos comerciales. El ensayo se estableció a 10 km al norte de la ciudad de Talca, en la estación experimental Panguilemo de la Universidad de Talca. En terreno se midió el diámetro basal y la altura por tres años a las seis plantas centrales de cada parcela, con cuatro repeticiones por híbrido para ambas densidades de plantación (5.000 y 10.000 plantas por hectárea. El volumen se calculó utilizando el exponente mórfico de un Paracono. El incremento volumétrico varió entre 5,306 y 15,828 m3 ha-1 año-1, detectando diferencias significativas entre los híbridos. El grupo de mayor productividad estuvo compuesto por cinco híbridos todos del catálogo del CTA. Este resultado demuestra que si se desea una mayor productividad en plantaciones dendroenergéticas que utilicen híbridos de Populus se deberían considerar algunos de los híbridos del catálogo del Centro Tecnológico del Álamo (CTA de la Universidad de Talca.

  18. Pharmacological potential of Populus nigra extract as antioxidant, anti-inflammatory, cardiovascular and hepatoprotective agent

    Institute of Scientific and Technical Information of China (English)

    Nadjet Debbache-Benaida; Dina Atmani-Kilani; Valrie Barbara Schini-Keirth; Nouredine Djebbli; Djebbar Atmani

    2013-01-01

    Objective: To evaluate antioxidant, anti-inflammatory, hepatoprotective and vasorelaxant activities of Populus nigra flower buds ethanolic extract. Methods: Antioxidant and anti-inflammatory activities of the extract were assessed using respectively the ABTS test and the animal model of carrageenan-induced paw edema. Protection from hepatic toxicity caused by aluminum was examined by histopathologic analysis of liver sections. Vasorelaxant effect was estimated in endothelium-intact and-rubbed rings of porcine coronary arteries precontracted with high concentration of U46619. Results:The results showed a moderate antioxidant activity (40%), but potent anti-inflammatory activity (49.9%) on carrageenan-induced mice paw edema, and also as revealed by histopathologic examination, complete protection against AlCl3-induced hepatic toxicity. Relaxant effects of the same extract on vascular preparation from porcine aorta precontracted with high concentration of U46619 were considerable at 10-1 g/L, and comparable (P>0.05) between endothelium-intact (67.74%, IC50=0.04 mg/mL) and-rubbed (72.72%, IC50=0.075 mg/mL) aortic rings. Conclusions: The extract exerted significant anti-inflammatory, hepatoprotective and vasorelaxant activities, the latter being endothelium-independent believed to be mediated mainly by the ability of components present in the extract to exert antioxidant properties, probably related to an inhibition of Ca2+influx.

  19. The Populus homeobox gene ARBORKNOX2 regulates cell differentiation during secondary growth.

    Science.gov (United States)

    Du, Juan; Mansfield, Shawn D; Groover, Andrew T

    2009-12-01

    The stem cells of the vascular cambium divide to produce daughter cells, which in turn divide before undergoing differentiation during the radial growth of woody stems. The genetic regulation of these developmental events is poorly understood, however. We report here the cloning and functional characterization of a Populus class-I KNOX homeobox gene, ARBORKNOX2 (ARK2), which we show influences terminal cell differentiation and cell wall properties during secondary growth. In the early stages of secondary growth, ARK2 is expressed broadly in the cambial zone and in terminally differentiating cell types, before becoming progressively restricted to the cambium. ARK2 overexpression and synthetic miRNA-suppression transgenics reveal positive correlations between ARK2 expression level and the timing of cambium formation, the width of the cambial zone and inhibition of cambial daughter cell differentiation. These phenotypes in turn correlate with changes in the expression of genes affecting transcription, cell division, auxin and cell wall synthesis. Notably, wood properties associated with secondary cell wall synthesis are negatively associated with ARK2 expression, including lignin and cellulose content. Together, our results suggest that ARK2 functions primarily to regulate a complex suite of genes that together influence cell differentiation during secondary growth. We propose that ARK2 may represent a co-evolved transcriptional module that influences complex, adaptive wood properties.

  20. Duplication of Locus Coding of Malate Dehydrogenase in Populus tomentosa Carr.

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Horizontal starch-gel electrophoresis was used to study crude enzyme extraction from young leaves of 234 clones of Populus tomentosa Carr. selected from nine provenances in North China. Ten enzyme systems were resolved. One hundred and fifty-six clones showing unusual allozyme band patterns at locus Mdh-1 were found. Three allozyme bands at locus Mdh-1 were 9:6:1 in concentration. Further studies on the electrophoretic patterns of ground mixed pollen extraction of 30 male clones selected at random from the 156 clones were conducted and it was found that allozyme bands at locus Mdh-1 were composed of two dark-stained bands and a weak band. Only one group of the malate dehydrogenase (MDH) zymogram composed of two bands was obtained from the electrophoretic segregation of pollen leachate of the same clones. A comparison of the electrophoretic patterns one another suggested that the locus Mdh-1 coding malate dehydrogenase in diploid species of P. tomentosa was duplicated. The duplicate gene locus possessed three same alleles and was located in mitochondria. The locus duplication of alleles coding malate dehydrogenase in P. tomentosa was discovered and reported for the first time.

  1. Variation Analysis of Seed and Seedling Traits of Cross Combination Progenies in Populus

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Twenty-five species and hybrids in Populus were used as parents, and 26 cross combinations, including more than 5 000 seedlings, were obtained by artificial cross breeding. The length of infructescence, number of seeds per infructescence, thousand-seed weight, germination rate of seeds among these cross combinations were tested. The results indicated that the cross combinational effects were significant for these traits, and demonstrated that the length of infructescence, thousand-seed weight were positively affected by female parent. In addition, seedling height, diameter above ground, diameter at breast height (DBH) of 17 cross combination progenies were investigated. The analysis of mean and standard deviation of these three traits showed that seedling height, diameter above ground, DBH had extensive variation among combinations and individuals within combination. Variance analysis and estimate of heritability indicated that the three traits had wide variation and were controlled by heredity. It was feasible to select superior cross combinations and seedlings. Further more, the result of multiple comparison showed that P. deltoides 'Lux' × P. deltoides 'D324', P. ussuriensis cl. 'U4' × P. deltoides 'T66', P. ussuriensis cl. 'U4' × P. deltoides 'T26', P. deltoides 'Lux' × P. ussuriensis cl. 'U3', (P. tomentosa × P. bolleana) × (P. alba × P. glandulosa), (P. alba × P. tomentosa) × (P. alba × P. glandulosa ), and (P. alba × P. glandulosa 'No. 2') × P. tomentosa 'Lumao 50' were superior cross combinations with higher growth rate. Finally, 123 elite seedlings were selected for further test.

  2. Diversity of soil microorganisms in natural Populus euphratica forests in Xinjiang, northwestern China

    Institute of Scientific and Technical Information of China (English)

    Haili QIAO; Chengming TIAN; Youqing LUO; Jianhua SUN; Xiaofeng FENG

    2008-01-01

    To better understand the distribution of soil microorganisms in Populus euphratica forests in Xin-jiang, northwestern China, we studied and compared the populations and numbers of bacteria, fungi and actino-mycetes in the soil at four different age stages of natural P. euphratica forests, i.e., juvenile forests, middle-aged for-ests, over-mature forests and degraded forests. Results showed that there were clear differences in the amount of microorganism biomass and composition rates across the four forest stages. Dominant and special microorgan-isms were present in each of the four different soil layers.The vertical distribution showed that the microorganism biomass decreased with increasing soil depth. The popu-lation of microorganisms was the lowest at 31-40 cm of soil depth. The microorganisms consisted of bacteria, actinomycetes, as well as fungi. Bacteria were the chief component of microorganisms and were widely distribu-ted, but fungi were scarce in some soil layers. Aspergillus was the dominant genus among the 11 genera of fungi isolated from the soil in different age stages of P. euphra-tica forests.

  3. [Simulation of soil water dynamics in triploid Populus tomentosa root zone under subsurface drip irrigation].

    Science.gov (United States)

    Xi, Ben-Ye; Jia, Li-Ming; Wang, Ye; Li, Guang-De

    2011-01-01

    Based on the observed data of triploid Populus tomentosa root distribution, a one-dimensional root water uptake model was proposed. Taking the root water uptake into account, the soil water dynamics in triploid P. tomentosa root zone under subsurface drip irrigation was simulated by using HYDRUS model, and the results were validated with field experiment. Besides, the HYDRUS model was used to study the effects of various irrigation technique parameters on soil wetting patterns. The RMAE for the simulated soil water content by the end of irrigation and approximately 24 h later was 7.8% and 6.0%, and the RMSE was 0.036 and 0.026 cm3 x cm(-3), respectively, illustrating that the HYDRUS model performed well in simulating the short-term soil water dynamics in triploid P. tomentosa root zone under drip irrigation, and the root water uptake model was reasonable. Comparing with 2 and 4 L x h(-1) of drip discharge and continuous irrigation, both the 1 L x h(-1) of drip discharge and the pulsed irrigation with water applied intermittently in 30 min periods could increase the volume of wetted soil and reduce deep percolation. It was concluded that the combination of 1 L x h(-1) of drip discharge and pulsed irrigation should be the first choice when applying drip irrigation to triploid P. tomentosa root zone at the experiment site.

  4. Water and energy consumption of Populus spp. bioenergy systems: A case study in Southern Europe

    Energy Technology Data Exchange (ETDEWEB)

    Sevigne, Eva [SosteniPrA (UAB-IRTA), Institut de Ciencia i Tecnologia Ambientals (ICTA), Universitat Autonoma de Barcelona (UAB), 08193 Bellaterra, Barcelona (Spain); Gasol, Carles M. [SosteniPrA (UAB-IRTA), Institut de Ciencia i Tecnologia Ambientals (ICTA), Universitat Autonoma de Barcelona (UAB), 08193 Bellaterra, Barcelona (Spain); Inedit Innovacio S.L. Parc de Recerca de la Universitat Autonoma de Barcelona (UAB), Carretera de Cabrils Km2, 08348 Barcelona (Spain); Brun, Filippo [Dipartimento di Economia e Ingegneria Agraria Forestale e Ambientale, University of Torino (Italy); Rovira, Laura; Pages, Josep Maria; Camps, Francesc [IRTA-Mas Badia, Institut de Recerca i Tecnologia Agroalimentaria (IRTA), Estacion Experimental Fundacion Mas Badia Ctra, De la Tallada, s/n, 17134 La Tallada, Girona (Spain); Rieradevall, Joan; Gabarrell, Xavier [SosteniPrA (UAB-IRTA), Institut de Ciencia i Tecnologia Ambientals (ICTA), Universitat Autonoma de Barcelona (UAB), 08193 Bellaterra, Barcelona (Spain); Chemical Engineering Department, Universitat Autonoma de Barcelona (UAB), 08193 Bellaterra, Barcelona (Spain)

    2011-02-15

    With the objectives of climate change mitigation and energy independence, energy crops have been proposed as an alternative to fossil fuels. In recent years short rotation energy crops have been promoted because they provide biomass in short periods of time. However, the impacts of water consumption, in both the impact on the energy balance due to the consumption of irrigation as the impacts on existing water resources, have not been analyzed in depth. This study evaluates the relationship between water, energy and CO{sub 2} emissions of a plot of Populus spp. in Spain with the aim of evaluating the feasibility of its implementation as large-scale cultivation. For the energy and environmental assessment it has been used the life cycle analysis methodology. The results show positive energy balance and environmental improvement respect other energies such as natural gas. Consumption of water required to avoid a kg of CO{sub 2} is 4.6 m{sup 3} and per unit of energy obtained is 45 m{sup 3} GJ{sup -1} considering a life cycle approach and in relation to the water availability of the basin could increase the pressure. Hence, in order to establish energy crops for climate change mitigation water consumption associated must be taken into account for future energy planning. (author)

  5. Sex-related adaptive responses to interaction of drought and salinity in Populus yunnanensis.

    Science.gov (United States)

    Chen, Lianghua; Zhang, Sheng; Zhao, Hongxia; Korpelainen, Helena; Li, Chunyang

    2010-10-01

    We used Populus yunnanensis Dode., a native dioecious species in southwestern China, as a model species to study morphological, physiological, biochemical and ultrastructural responses to drought, salinity and their combination. Females exhibited more growth inhibition, gas exchange rate depression and reactive oxygen species (ROS) accumulation; higher lipid peroxide levels, lower osmotic adjustment capacity and ascorbate-glutathione cycle enzyme activities; and more damage to cell organelles than did males under drought, salinity and especially under their combination. In addition, we found sex-specific responses in total chlorophyll content (TC), carotenoid concentration and carbon isotope composition under different osmotic stresses. Our results indicated that: (1) females are more sensitive and suffer from greater negative effects than do males under drought, salinity and especially under their combination; (2) sexual differences in adaptive responses to drought, salinity and their combination are context dependent; and (3) sex-specific reactions under a combination of stresses are distinct from single-stress responses. Thus, these results provide evidence for adaptive differentiation between sexes in responses to osmotic stresses and in the sensitivity to environmental change. © 2010 Blackwell Publishing Ltd.

  6. Phenology and climate relationships in aspen (Populus tremuloides Michx.) forest and woodland communities of southwestern Colorado

    Science.gov (United States)

    Meier, Gretchen A.; Brown, Jesslyn F.; Evelsizer, Ross J.; Vogelmann, James E.

    2014-01-01

    Trembling aspen (Populus tremuloides Michx.) occurs over wide geographical, latitudinal, elevational, and environmental gradients, making it a favorable candidate for a study of phenology and climate relationships. Aspen forests and woodlands provide numerous ecosystem services, such as high primary productivity and biodiversity, retention and storage of environmental variables (precipitation, temperature, snow–water equivalent) that affect the spring and fall phenology of the aspen woodland communities of southwestern Colorado. We assessed the land surface phenology of aspen woodlands using two phenology indices, start of season time (SOST) and end of season time (EOST), from the U.S. Geological Survey (USGS) database of conterminous U.S. phenological indicators over an 11-year time period (2001–2011). These indicators were developed with 250 m resolution remotely sensed data from the Moderate Resolution Imaging Spectroradiometer processed to highlight vegetation response. We compiled data on SOST, EOST, elevation, precipitation, air temperature, and snow water equivalent (SWE) for selected sites having more than 80% cover by aspen woodland communities. In the 11-year time frame of our study, EOST had significant positive correlation with minimum fall temperature and significant negative correlation with fall precipitation. SOST had a significant positive correlation with spring SWE and spring maximum temperature.

  7. Characteristics and dynamics analysis of Populus euphratica populations in the middle reaches of Tarim River

    Institute of Scientific and Technical Information of China (English)

    JunXia WU; XiMing ZHANG; ChaoZhou DENG; GuoJun LIU; Hong LI

    2010-01-01

    Populus euphratica Oliv.is widely distributed along the Tarim River.Maintaining stability of P.euphratica population is important to local development.This study explored the static life table,survivorship curves and four function curves(survival rate,cumulative mortality rate,mortality density,and hazard rate),and development index of P.euphratica population in the middle reaches of Tarim River.The results indicated that the age structure of P.euphratica population belonged to positive pyramidal type,which meant young age-class individuals occupied most populations.The number of Ⅰ-Ⅱ age classes accounted for 66.2% of whole population,and this indicated that there were abundant subsequent seedlings resources to support the growth of P.euphratica population in the middle reaches of Tarim River.The survivorship curve of P.euphratica belonged to the Deevey Ⅲ(concave-type)and the development index was 47.72%.Four function curves revealed that the individuals of P.euphratica sharply decreased at the initial stage and then leveled off at the late stage of survival curve.Time sequence prediction models predicted that the number of midlife individuals would increase in future 10,20,30 years,and P.euphratica population grew steadily as a result of rich saplings.

  8. Analysis of synonymous codon usage in chloroplast genome of Populus alba

    Institute of Scientific and Technical Information of China (English)

    ZHOU Meng; LONG Wei; LI Xia

    2008-01-01

    The pattern of codon usage in the chloroplast genome of Populus alba was investigated.Correspondence analysis (a commonly used multivariate statistical approach) and method of effective number of codons (ENc)-plot were conducted to analyze synonymous codon usage.The results of correspondence analysis showed that the distribution of genes on the major axis was significantly correlated with the frequency of use of G+C in synonymously variable third position of sense codon (GC3S),(r=0.349),and the positions of genes on the axis 2 and axis 3 were significantly correlated with CAI (r=-0.348,p<0.01 and r=0.602,p<0.01).The ENc for most genes was similar to that for the expected ENc based on the GC3S,but several genes with low ENC values were lying below the expected curve.All of these data indicated that codon usage was dominated by a mutational bias in chloroplast genome of P.alba.The selection in nature for translational efficiency only played a minor role in shaping codon usage in the chloroplast genome of P.alba.

  9. Allergic contact dermatitis from salicyl alcohol and salicylaldehyde in aspen bark (Populus tremula).

    Science.gov (United States)

    Aalto-Korte, Kristiina; Välimaa, Jarmo; Henriks-Eckerman, Maj-Len; Jolanki, Riitta

    2005-02-01

    Salicyl alcohol or 2-methylolphenol is a well-known allergen in phenol-formaldehyde resins and a strong sensitizer in guinea pigs. There is 1 previous report of allergic contact dermatitis from salicyl alc