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Sample records for populus tremuloides internodes

  1. Rapid mortality of Populus tremuloides in southwestern Colorado, USA

    Treesearch

    James J. Worrall; Leanne Egeland; Thomas Eager; Roy A. Mask; Erik W. Johnson; Philip A. Kemp; Wayne D. Shepperd

    2008-01-01

    Concentrated patches of recent trembling aspen (Populus tremuloides) mortality covered 56,091 ha of Colorado forests in 2006. Mortality has progressed rapidly. Area affected increased 58% between 2005 and 2006 on the Mancos-Dolores Ranger District, San Juan National Forest, where it equaled nearly 10% of the aspen cover type. In four stands that were...

  2. Inoculation methods for Populus tremuloides resistant to Hypoxylon canker

    Treesearch

    S. A. Enebak; Michael E. Ostry; N. A. Anderson

    1999-01-01

    Canker expansion and the amount of callus tissue formed were measured monthly on 60 ramets from each of five trembling aspen (Populus tremuloides Michx.) clones that had been inoculated in wounds with Entoleuca mammata (= Hypoxylon marnmatum (Wahl.) Mill) over a 12-month period. At the clone level, the prevalence...

  3. Widespread triploidy in western North American aspen (Populus tremuloides)

    Treesearch

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

    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...

  4. Populus tremuloides mortality near the southwestern edge of its range

    Treesearch

    Thomas J. Zegler; Margaret M. Moore; Mary L. Fairweather; Kathryn B. Ireland; Peter Z. Fule

    2012-01-01

    Mortality and crown dieback of quaking aspen (Populus tremuloides) were extensive on the Williams Ranger District, Kaibab National Forest in northern Arizona. We collected data from a random sample of 48 aspen sites to determine the relationship of predisposing site and stand factors and contributing agents to ramet mortality. Mortality of overstory (P10.1 cm DBH)...

  5. Widespread Triploidy in Western North American Aspen (Populus tremuloides)

    PubMed Central

    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. PMID:23119006

  6. Soil microbial community responses to altered lignin biosynthesis in Populus tremuloides vary among three distinct soils

    Treesearch

    Kate L. Bradley; Jessica E. Hancock; Christian P. Giardina; Kurt S. Pregitzer

    2007-01-01

    The development and use of transgenic plants has steadily increased, but there are still little data about the responses of soil microorganisms to these genetic modifications. We utilized a greenhouse trial approach to evaluate the effects of altered stem lignin in trembling aspen (Populus tremuloides) on soil microbial communities in three soils...

  7. Transcriptome characterization and detection of gene expression differences in aspen (Populus tremuloides)

    Treesearch

    Hardeep S. Rai; Karen E. Mock; Bryce A. Richardson; Richard C. Cronn; Katherine J. Hayden; Jessica W. Wright; Brian J. Knaus; Paul G. Wolf

    2013-01-01

    Aspen (Populus tremuloides) is a temperate North American tree species with a geographical distribution more extensive than any other tree species on the continent. Because it is economically important for pulp and paper industries and ecologically important for its role as a foundation species in forest ecosystems, the decline of aspen in large...

  8. Decline of aspen (Populus tremuloides) in the Interior West [Abstract 2

    Treesearch

    Dale L. Bartos

    1997-01-01

    It is commonly recognized that aspen (Populus tremuloides) ecosystems in the Interior West provide numerous benefits: (1) forage for livestock, (2) habitat for wildlife, (3) water for downstream users, (4) esthetics, (5) sites for recreational opportunities, (6) wood fiber, and (7) landscape diversity. Loss or potential loss of aspen on these lands can be attributed...

  9. Influence of climate on the growth of quaking aspen (Populus tremuloides) in Colorado and southern Wyoming

    Treesearch

    M. M. Dudley; Jose Negron; N. A. Tisserat; W. D. Shepperd; W. R. Jacobi

    2015-01-01

    We analyzed a series of increment cores collected from 260 adult dominant or co-dominant quaking aspen (Populus tremuloides Michx.) trees from national forests across Colorado and southern Wyoming in 2009 and 2010. Half of the cores were collected from trees in stands with a high amount of crown dieback, and half were from lightly damaged stands. We define the level of...

  10. Plant growth, biomass partitioning and soil carbon formation in response to altered lignin biosynthesis in Populus tremuloides

    Treesearch

    Jessica E. Hancock; Wendy M. Loya; Christian P. Giardina; Laigeng Li; Vincent L. Chiang; Kurt S. Pregitzer

    2007-01-01

    We conducted a glasshouse mesocosm study that combined 13C isotope techniques with wild-type and transgenic aspen (Populus tremuloides) in order to examine how altered lignin biosynthesis affects plant production and soil carbon formation. Our transgenic aspen lines expressed low stem lignin concentration but normal cellulose...

  11. Earthworms, arthropods and plant litter decomposition in aspen (Populus tremuloides) and lodgepole pine(Pinus contorta) forests in Colorado, USA

    Treesearch

    Grizelle Gonzalez; Timothy R. Seastedt; Zugeily Donato

    2003-01-01

    We compared the abundance and community composition of earthworms, soil macroarthropods, and litter microarthropods to test faunal effects on plant litter decomposition rates in two forests in the subalpine in Colorado, USA. Litterbags containing recently senesced litter of Populus tremuloides (aspen) and Pinus contorta (lodgepole pine) were placed in aspen and pine...

  12. Elevated growth temperatures alter hydraulic characteristics in trembling aspen (Populus tremuloides) seedlings: implications for tree drought tolerance

    Treesearch

    Danielle A. Way; Jean-Christophe Domec; Robert B. Jackson

    2013-01-01

    Although climate change will alter both soil water availability and evaporative demand, our understanding of how future climate conditions will alter tree hydraulic architecture is limited. Here, we demonstrate that growth at elevated temperatures (ambient +5 °C) affects hydraulic traits in seedlings of the deciduous boreal tree species Populus tremuloides, with the...

  13. Changes in growth, leaf abscission, and biomass associated with seasonal tropospheric ozone exposures of Populus tremuloides clones and seedlings

    Treesearch

    D.F. Karnosky; Z.E. Gagnon; R.E. Dickson; M.D. Coleman; E.H. Lee; J.G. Isebrands

    1996-01-01

    The effects of single-season tropospheric ozone (03) exposures on growth, leaf abscission, and biomass of trembling aspen (Populus tremuloides Michx.) rooted cuttings and seedlings were studied. Plants were grown in the Upper Peninsula of Michigan in open-top chambers with 03 exposures that ranged from...

  14. Decay of aspen (Populus tremuloides Michx.) wood in moist and dry boreal, temperate, and tropical forest fragments

    Treesearch

    Grizelle Gonzalez; William Gould; Andrew T. Hudak; Teresa Nettleton Hollingsworth

    2008-01-01

    In this study, we set up a wood decomposition experiment to i) quantify the percent of mass remaining, decay constant and performance strength of aspen stakes (Populus tremuloides) in dry and moist boreal (Alaska and Minnesota, USA), temperate (Washington and Idaho, USA), and tropical (Puerto Rico) forest types, and ii) determine the effects of...

  15. Differences in leaf characteristics between ozone-sensitive and ozone-tolerant hybrid aspen (Populus tremula x Populus tremuloides) clones.

    PubMed

    Häikiö, Elina; Freiwald, Vera; Julkunen-Tiitto, Riitta; Beuker, Egbert; Holopainen, Toini; Oksanen, Elina

    2009-01-01

    The authors analyzed a suite of leaf characteristics that might help to explain the difference between ozone-sensitive and ozone-tolerant hybrid aspen (Populus tremula L. x Populus tremuloides Michx.) clones. An open-field experiment comprising ambient ozone and 1.5x ambient ozone concentration (about 35 ppb) and two soil nitrogen regimes (60 and 140 kg N ha(-1) year(-1)) was conducted over two growing seasons on potted plants of eight hybrid aspen clones. Four of the clones had previously been determined to be ozone sensitive based on impaired growth in response to elevated ozone concentration. Photosynthetic rate, chlorophyll fluorescence, and concentrations of chlorophyll, protein and carbohydrates were analyzed three times during the second growing season, and foliar phenolic concentrations were measured at the end of the second growing season. Nitrogen amendment counteracted the effects of ozone, but had no effect on growth-related ozone sensitivity of the clones. Ozone-sensitive clones had higher photosynthetic capacity and higher concentrations of Rubisco and phenolics than ozone-tolerant clones, but the effects of ozone were similar in the sensitive and tolerant groups. Nitrogen addition had no effect on phenolic concentration, but elevated ozone concentration increased the concentrations of chlorogenic acid and (+)-catechin. This study suggests that condensed tannins and catechin, but not salicylates or flavonol glycosides, play a role in the ozone tolerance of hybrid aspen.

  16. Gender-specific and intraspecific responses of trembling aspen (Populus tremuloides) to elevated atmospheric carbon dioxide

    NASA Astrophysics Data System (ADS)

    Wang, Xianzhong

    I studied gender-specific and intraspecific variations in the physiological responses of Populus tremuloides to elevated CO2 as affected by soil N availability. I also synthesized leaf dark respiration data from independent studies using meta-analysis. Net CO2 assimilation rate (A) of male P. tremuloides was 17.8 and 26.2 μmol m-2 s-1 at ambient and elevated CO2, significantly higher than A of females of 15.6 and 21.0 μmol m-2 s-1 . Male trembling aspen had a higher maximum rate of CO2 fixation by Rubisco and area-based leaf dark respiration (Rda). Mass-based leaf Rd (Rdm), however, was unaffected by gender and CO2 concentration, although the results of meta-analysis on 44 independent observations showed that Rdm was reduced 18.4% by elevated CO2. We found a positive correlation between Rd a and leaf starch content, which was higher at elevated CO2, but no correlation between Rda and leaf N content was observed, suggesting the importance of starch content in determining the magnitude of respiration. Total biomass accumulation of female P. tremuloides was higher than that of males in low-N soil and at ambient CO2, but not in other treatments. Elevated CO2, on the other hand, significantly increased total biomass of both male and female trees in low- and high-N soil, with the increase ranging from 22-70% for female and 58-66% for male trees. There was a significant CO2 x genotype interaction in photosynthetic responses to CO2 enrichment, wherein A was significantly enhanced by elevated CO2 for five genotypes in high-N soil and for four genotypes in low-N soil. Enhancement of A by elevated CO2 ranged from 14% to 68%. We found a correlation between the degree of A enhancement to elevated CO2 and stomatal sensitivity to CO2. Stomatal conductance and A of different genotypes also responded differentially to drought stress. Our results suggest that P. tremuloides genotypes and genders respond differentially in A and Rd to rising atmospheric CO2 , with the degree of

  17. Genotypic variation in physiological and growth responses of Populus tremuloides to elevated atmospheric CO2 concentration.

    PubMed

    Wang, X; Curtis, P S; Pregitzer, K S; Zak, D R

    2000-09-01

    Physiological and biomass responses of six genotypes of Populus tremuloides Michx., grown in ambient t (357 micromol mol(-1)) or twice ambient (707 micromol mol(-1)) CO2 concentration ([CO2]) and in low-N or high-N soils, were studied in 1995 and 1996 in northern Lower Michigan, USA. There was a significant CO2 x genotype interaction in photosynthetic responses. Net CO2 assimilation (A) was significantly enhanced by elevated [CO2] for five genotypes in high-N soil and for four genotypes in low-N soil. Enhancement of A by elevated [CO2] ranged from 14 to 68%. Genotypes also differed in their biomass responses to elevated [CO2], but biomass responses were poorly correlated with A responses. There was a correlation between magnitude of A enhancement by elevated [CO2] and stomatal sensitivity to CO2. Genotypes with low stomatal sensitivity to CO2 had a significantly higher A at elevated [CO2] than at ambient [CO2], but elevated [CO2] did not affect the ratio of intercellular [CO2] to leaf surface [CO2]. Stomatal conductance and A of different genotypes responded differentially to recovery from drought stress. Photosynthetic quantum yield and light compensation point were unaffected by elevated [CO2]. We conclude that P. tremuloides genotypes will respond differentially to rising atmospheric [CO2], with the degree of response dependent on other abiotic factors, such as soil N and water availability. The observed genotypic variation in growth could result in altered genotypic representation within natural populations and could affect the composition and structure of plant communities in a higher [CO2] environment in the future.

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

    PubMed

    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.

  19. Phenology and climate relationships in aspen (Populus tremuloides Michx.) forest and woodland communities of southwestern Colorado

    USGS Publications Warehouse

    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.

  20. Stomatal Conductance and Sulfur Uptake of Five Clones of Populus tremuloides Exposed to Sulfur Dioxide 1

    PubMed Central

    Kimmerer, Thomas W.; Kozlowski, T. T.

    1981-01-01

    Plants of five clones of Populus tremuloides Michx. were exposed to 0, 0.2 or 0.5 microliter per liter SO2 for 8 hours in controlled environment chambers. In the absence of the pollutant, two pollution-resistant clones maintained consistently lower daytime diffusive conductance (LDC) than did a highly susceptible clone or two moderately resistant clones. Differences in LDC among the latter three clones were not significant. At 0.2 microliter per liter SO2, LDC decreased in the susceptible clone after 8 hours fumigation while the LDC of the other clones was not affected. Fumigation with 0.5 microliter per liter SO2 decreased LDC of all five clones during the fumigation. Rates of recovery following fumigation varied with the clone, but the LDC of all clones had returned to control values by the beginning of the night following fumigation. Night LDC was higher in the susceptible clone than in the other clones. Fumigation for 16 hours (14 hours day + 2 hours night) with 0.4 microliter per liter SO2 decreased night LDC by half. Sulfur uptake studies generally confirmed the results of the conductance measurements. The results show that stomatal conductance is important in determining relative susceptibility of the clones to pollution stress. PMID:16661807

  1. Plant Community Chemical Composition Influences Trembling Aspen (Populus tremuloides) Intake by Sheep.

    PubMed

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

    2017-07-25

    Nutrients and plant secondary compounds in aspen (Populus tremuloides) may interact with nutrients in the surrounding vegetation to influence aspen use by herbivores. Thus, this study aimed to determine aspen intake and preference by sheep in response to supplementary nutrients or plant secondary compounds (PSC) present in aspen trees. Thirty-two lambs were randomly assigned to one of four molasses-based supplementary feeds to a basal diet of tall fescue hay (N = 8) during three experiments. The supplements were as follows: (1) high-protein (60% canola meal), (2) a PSC (6% quebracho tannins), (3) 25% aspen bark, and (4) control (100% molasses). Supplements were fed from 0700 to 0900, then lambs were fed fresh aspen leaves collected from stands containing high (Experiment 1, 2) or low (Experiment 3) concentrations of phenolic glycosides (PG). In Experiment 2, lambs were simultaneously offered aspen, a forb (Lathyrus pauciflorus), and a grass (Bromus inermis) collected from the aspen understory. Animals supplemented with high protein or tannins showed greater intake of aspen leaves than animals supplemented with bark or the control diet (P < 0.05), likely because some condensed tannins have a positive effect on protein nutrition and protein aids in PSC detoxification. Overall, animals supplemented with bark showed the lowest aspen intake, suggesting PSC in bark and aspen leaves had additive inhibitory effects on intake. In summary, these results suggest that not only the concentration but also the types and proportions of nutrients and chemical defenses available in the plant community influence aspen use by herbivores.

  2. Inhibitor studies of leaf lamina hydraulic conductance in trembling aspen (Populus tremuloides Michx.) leaves.

    PubMed

    Voicu, Mihaela C; Zwiazek, Janusz J

    2010-02-01

    The present study investigated leaf water transport properties in trembling aspen (Populus tremuloides) leaves. Leaf lamina hydraulic conductance (K(lam)) and stomatal conductance (g(s)) were drastically suppressed by NaF (a general metabolic inhibitor). In leaves treated with 0.2 mM HgCl(2) (an aquaporin blocker), K(lam) declined by 22% when the leaves were sampled in June but the decline was not significant when the leaves were sampled in August. The leaves sampled in June that transpired 30 mM beta-mercaptoethanol following mercury application showed similar K(lam) as those in control leaves transpiring distilled water. When leaves were pressure-infiltrated with 0.1 mM HgCl(2), K(lam) significantly declined by 25%. Atrazine (a photosystem II inhibitor) drastically reduced leaf net CO(2) uptake by the leaves from seedlings and mature trees but did not have any effect on K(lam) regardless of the irradiance at the leaf level during the K(lam) measurements. When PTS(3) (trisodium 3-hydroxy-5,8,10-pyrenetrisulphonate) apoplastic tracer was pressure-infiltrated inside the leaves, its concentration in the leaf exudates did not change from ambient light to high irradiance treatment and declined in the presence of HgCl(2) in the treatment solution. Trembling aspen K(lam) appears to be linked to leaf metabolism and is uncoupled from the short-term variations in photosynthesis. Aquaporin-mediated water transport does not appear to constitute the dominant pathway for the pressure-driven water flow in the leaves of trembling aspen trees.

  3. Extrafloral Nectaries in Aspen (Populus tremuloides): Heritable Genetic Variation and Herbivore-induced Expression

    PubMed Central

    Wooley, Stuart C.; Donaldson, Jack R.; Gusse, Adam C.; Lindroth, Richard L.; Stevens, Michael T.

    2007-01-01

    Background and Aims A wide variety of plants produce extrafloral nectaries (EFNs) that are visited by predatory arthropods. But very few studies have investigated the relationship between plant genetic variation and EFNs. The presence of foliar EFNs is highly variable among different aspen (Populus tremuloides) genotypes and the EFNs are visited by parasitic wasps and predatory flies. The aim here was to determine the heritability of EFNs among aspen genotypes and age classes, possible trade-offs between direct and indirect defences, EFN induction following herbivory, and the relationship between EFNs and predatory insects. Methods EFN density was quantified among aspen genotypes in Wisconsin on trees of different ages and broad-sense heritability from common garden trees was calculated. EFNs were also quantified in natural aspen stands in Utah. From the common garden trees foliar defensive chemical levels were quantified to evaluate their relationship with EFN density. A defoliation experiment was performed to determine if EFNs can be induced in response to herbivory. Finally, predatory arthropod abundance among aspen trees was quantified to determine the relationship between arthropod abundance and EFNs. Key Results Broad-sense heritability for expression (0·74–0·82) and induction (0·85) of EFNs was high. One-year-old trees had 20% greater EFN density than 4-year-old trees and more than 50% greater EFN density than ≥10-year-old trees. No trade-offs were found between foliar chemical concentrations and EFN density. Predatory fly abundance varied among aspen genotypes, but predatory arthropod abundance and average EFN density were not related. Conclusions Aspen extrafloral nectaries are strongly genetically determined and have the potential to respond rapidly to evolutionary forces. The pattern of EFN expression among different age classes of trees appears to follow predictions of optimal defence theory. The relationship between EFNs and predators likely

  4. Genotypic differences and prior defoliation affect re-growth and phytochemistry after coppicing in Populus tremuloides.

    PubMed

    Stevens, Michael T; Gusse, Adam C; Lindroth, Richard L

    2012-03-01

    Although considerable research has explored how tree growth and defense can be influenced by genotype, the biotic environment, and their interaction, little is known about how genotypic differences, prior defoliation, and their interactive effects persist in trees that re-grow after damage that severs their primary stem. To address these issues, we established a common garden consisting of twelve genotypes of potted aspen (Populus tremuloides) trees, and subjected half of the trees to defoliation in two successive years. At the beginning of the third year, all trees were severed at the soil surface (coppiced) and allowed to regenerate for five months. Afterwards, we counted the number of root and stump sprouts produced and measured the basal diameter (d) and height (h) of the tallest ramet in each pot. We collected leaves one and two years after the second defoliation and assessed levels of phenolic glycosides, condensed tannins, and nitrogen. In terms of re-growth, we found that the total number of sprouts produced varied by 3.6-fold among genotypes, and that prior defoliation decreased total sprout production by 24%. The size (d(2)h) of ramets, however, did not differ significantly among genotypes or defoliation classes. In terms of phytochemistry, we observed genotypic differences in concentrations of all phytochemicals assessed both one and two years after the second defoliation. Two years after defoliation, we observed effects of prior defoliation in a genotype-by-defoliation interaction for condensed tannins. Results from this study demonstrate that genotypic differences and impacts of prior defoliation persist to influence growth and defense traits in trees even after complete removal of above-ground stems, and thus likely influence productivity and plant-herbivore interactions in forests affected by natural disturbances or actively managed through coppicing.

  5. Scale dependence of disease impacts on quaking aspen (Populus tremuloides) mortality in the southwestern United States.

    PubMed

    Bell, David M; Bradford, John B; Lauenroth, William K

    2015-07-01

    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. We found that disease prevalence depended primarily on tree size, tree allometry, and spatial variation in precipitation, while mortality depended on tree size, allometry, competition, spatial variation in summer temperature, and both temporal and spatial variation in summer precipitation. Disease prevalence was highest in large trees with low slenderness found on dry sites. For healthy trees, mortality decreased with diameter, slenderness, and temporal variation in summer precipitation, but increased with competition and spatial variation in summer temperature. Mortality of diseased trees decreased with diameter and aspen relative basal area and increased with mean summer temperature and precipitation. Disease infection increased aspen mortality, especially in trees of intermediate size and trees on plots at climatic extremes (i.e., cool, wet and warm, dry climates). By examining variation in disease prevalence, mortality of healthy trees, and mortality of diseased trees, we showed that the role of disease in aspen tree mortality depended on the scale of inference. For variation among individuals in diameter, disease tended to expose intermediate-size trees experiencing moderate

  6. Elevated Rocky Mountain elk numbers prevent positive effects of fire on quaking aspen (Populus tremuloides) recruitment

    USGS Publications Warehouse

    Smith, David Solance; Fettig, Stephen M.; Bowker, Matthew A.

    2016-01-01

    Quaking aspen (Populus tremuloides) is the most widespread tree species in North America and has supported a unique ecosystem for tens of thousands of years, yet is currently threatened by dramatic loss and possible local extinctions. While multiple factors such as climate change and fire suppression are thought to contribute to aspen’s decline, increased browsing by elk (Cervus elaphus), which have experienced dramatic population increases in the last ∼80 years, may severely inhibit aspen growth and regeneration. Fires are known to favor aspen recovery, but in the last several decades the spatial scale and intensity of wildfires has greatly increased, with poorly understood ramifications for aspen growth. Here, focusing on the 2000 Cerro Grande fire in central New Mexico – one of the earliest fires described as a “mega-fire” - we use three methods to examine the impact of elk browsing on aspen regeneration after a mega-fire. First, we use an exclosure experiment to show that aspen growing in the absence of elk were 3× taller than trees growing in the presence of elk. Further, aspen that were both protected from elk and experienced burning were 8.5× taller than unburned trees growing in the presence of elk, suggesting that the combination of release from herbivores and stimulation from fire creates the largest aspen growth rates. Second, using surveys at the landscape level, we found a correlation between elk browsing intensity and aspen height, such that where elk browsing was highest, aspen were shortest. This relationship between elk browsing intensity and aspen height was stronger in burned (r = −0.53) compared to unburned (r = −0.24) areas. Third, in conjunction with the landscape-level surveys, we identified possible natural refugia, microsites containing downed logs, shrubs etc. that may inhibit elk browsing by physically blocking aspen from elk or by impeding elk’s ability to move through the forest patch. We did not find any

  7. Stem wood properties of Populus tremuloides, Betula papyrifera and Acer saccharum saplings after three years of treatments to elevated carbon dioxide and ozone

    Treesearch

    Seija Kaakinen; Katri Kostiainen; Fredrik Ek; Pekka Saranpaa; Mark E. Kubiske; Jaak Sober; David F. Karnosky; Elina Vapaavuori

    2004-01-01

    The aim of this study was to examine the effects of elevated carbon dioxide [CO2] and ozone [O3] and their interaction on wood chemistry and anatomy of five clones of 3-year-old trembling aspen (Populus tremuloides Michx.). Wood chemistry was studied also on paper birch (Betula papyrifera...

  8. A review of the potential effects of climate change on quaking aspen (Populus tremuloides) in the Western United States and a new tool for surveying sudden aspen decline

    Treesearch

    Toni Lyn Morelli; Susan C. Carr

    2011-01-01

    We conducted a literature review of the effects of climate on the distribution and growth of quaking aspen (Populus tremuloides Michx.) in the Western United States. Based on our review, we summarize models of historical climate determinants of contemporary aspen distribution. Most quantitative climate-based models linked aspen presence and growth...

  9. Photosynthetic acclimation of overstory Populus tremuloides and understory Acer saccharum to elevated atmospheric CO2 concentration: interactions with shade and soil nitrogen

    Treesearch

    Mark E. Kubiske; Donald R. Zak; Kurt S. Pregitzer; Yu Takeuchi

    2002-01-01

    We exposed Populus tremuloides Michx. and Acer saccharum Marsh. to a factorial combination of ambient and elevated atmospheric CO2 concentrations ([CO2]) and high-nitrogen (N) and low-N soil treatments in open-top chambers for 3 years. Our objective was to compare photosynthetic...

  10. The impact of vessel size on vulnerability curves: data and models for within-species variability in saplings of aspen, Populus tremuloides Michx

    Treesearch

    Jing Cai; Melvin T. Tyree

    2010-01-01

    The objective of this study was to quantify the relationship between vulnerability to cavitation and vessel diameter within a species. We measured vulnerability curves (VCs: percentage loss hydraulic conductivity versus tension) in aspen stems and measured vessel-size distributions. Measurements were done on seed-grown, 4-month-old aspen (Populus tremuloides...

  11. Analysis of a Farquhar-von Caemmerer-Berry leaf-level photosynthetic rate model for Populus tremuloides in the context of modeling and measurement limitations

    Treesearch

    K.E. Lenz; G.E. Host; K. Roskoski; A. Noormets; A. Sober; D.F. Karnosky

    2010-01-01

    The balance of mechanistic detail with mathematical simplicity contributes to the broad use of the Farquhar, von Caemmerer and Berry (FvCB) photosynthetic rate model. Here the FvCB model was coupled with a stomatal conductance model to form an [A,gs] model, and parameterized for mature Populus tremuloides leaves under varying CO2...

  12. Characterizing recent phenological and climate relationships in trembling aspen (Populus tremuloides)

    NASA Astrophysics Data System (ADS)

    Meier, G.; Brown, J. F.; Vogelmann, J. E.; Evelsizer, R.

    2012-12-01

    Trembling aspen (Populus tremuloides, referred hereafter as Aspen) has an especially wide geographical distribution in North America, extending from Alaska across the Canadian provinces, the U.S., and south into Mexico. This deciduous species is successional, shade intolerant, and often exists as a dominant among other species at mid-elevations. Aspen occupies wide latitudinal, elevational, and environmental gradients making it a favorable candidate for a study of phenology and climate relationships. The phenological characterization in our Aspen study is derived from a database of conterminous U.S. phenological indicators hosted by the U.S. Geological Survey (http://phenology.cr.usgs.gov/index.php). Nine satellite-derived phenological indicators are calculated from 250m resolution Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI). From this database, we selected start of season (SOST), end of season (EOST), maximum NDVI (MaxN) and time integrated NDVI (TIN) to characterize and analyze the seasonal patterns of Aspen over a 10-year time period (2001-2010). Areas of continuous Aspen cover (≥ 80% Aspen cover type) derived from the LANDFIRE project were then used to extract elevation, precipitation, temperature, and snow water equivalent data. In the Rocky Mountains, Aspen recently suffered from multi-year drought stress accompanied by insect and disease infestations. Numerous studies have documented the existence of Sudden Aspen Decline (SAD) in Montana, Utah, Arizona, and Colorado, indicating that Aspen may be on the edge of its environmental tolerances in some areas. The satellite-derived phenology metrics, and climate and biogeographical indicators were the basis for characterizing Aspen seasonality and assessing the environmental context of SAD. Between several Aspen study areas, there was reasonably consistent progression in the SOST timing from low elevations to higher elevations. A less obvious progression was

  13. Stockability, growth, and yield of the circumboreal aspens (`populus tremuloides` michx., `p. tremula` l.). Forest Service research paper

    SciTech Connect

    Perala, D.A.; Leary, R.A.; Cieszewski, C.J.

    1995-01-10

    The authors show elsewhere that quaking aspen (Populus tremuloides Michx.) and its Eurasian counterpart, P. tremula L., form a single circumpolar superspecies when viewed from the standpoint of self-thinning rates and stockability. Here the authors expand their examination to the d.b.h.-age relationships and to growth series measurements from permanent plots of aspen stands of varying densities reported in the literature. They also attempt to account for the curvilinear trend in the self-thinning relationship they detected in young stands that forced them in their first analysis to truncate their usable data set to older stands. The resulting equations satisfy the need for a framework to study variation in aspen stockability. The equations can give useful regional estimates as well, but will need refitting to local data to satisfy needs for finer resolution.

  14. Association of Pinus banksiana Lamb. and Populus tremuloides Michx. seedling fine roots with Sistotrema brinkmannii (Bres.) J. Erikss. (Basidiomycotina).

    PubMed

    Potvin, Lynette R; Richter, Dana L; Jurgensen, Martin F; Dumroese, R Kasten

    2012-11-01

    Sistotrema brinkmannii (Bres.) J. Erikss. (Basidiomycotina, Hydanaceae), commonly regarded as a wood decay fungus, was consistently isolated from bareroot nursery Pinus banksiana Lamb. seedlings. S. brinkmannii was found in ectomycorrhizae formed by Thelephora terrestris Ehrh., Laccaria laccata (Scop.) Cooke, and Suillus luteus (L.) Roussel. In pure culture combinations with sterile P. banksiana and Populus tremuloides Michx. seedlings, S. brinkmannii colonized root cortical cells while not killing seedlings. Colonization by S. brinkmannii appeared to be intracellular but typical endo- or ectomycorrhizae were not formed. The fungus did not decay roots, although it was shown to produce cellulase in enzyme tests. Results suggest a unique association between S. brinkmannii and seedling roots that is neither mycorrhizal nor detrimental; its exact function remains to be elucidated.

  15. Laccaria bicolor aquaporin LbAQP1 is required for Hartig net development in trembling aspen (Populus tremuloides).

    PubMed

    Navarro-RóDenas, Alfonso; Xu, Hao; Kemppainen, Minna; Pardo, Alejandro G; Zwiazek, Janusz J

    2015-11-01

    The development of ectomycorrhizal associations is crucial for growth of many forest trees. However, the signals that are exchanged between the fungus and the host plant during the colonization process are still poorly understood. In this study, we have identified the relationship between expression patterns of Laccaria bicolor aquaporin LbAQP1 and the development of ectomycorrhizal structures in trembling aspen (Populus tremuloides) seedlings. The peak expression of LbAQP1 was 700-fold higher in the hyphae within the root than in the free-living mycelium after 24 h of direct interaction with the roots. Moreover, in LbAQP1 knock-down strains, a non-mycorrhizal phenotype was developed without the Hartig net and the expression of the mycorrhizal effector protein MiSSP7 quickly declined after an initial peak on day 5 of interaction of the fungal hyphae with the roots. The increase in the expression of LbAQP1 required a direct contact of the fungus with the root and it modulated the expression of MiSSP7. We have also determined that LbAQP1 facilitated NO, H2 O2 and CO2 transport when heterologously expressed in yeast. The report demonstrates that the L. bicolor aquaporin LbAQP1 acts as a molecular signalling channel, which is fundamental for the development of Hartig net in root tips of P. tremuloides. © 2015 John Wiley & Sons Ltd.

  16. Suppression subtractive hybridization-mediated transcriptome analysis from multiple tissues of aspen (Populus tremuloides) altered in phenylpropanoid metabolism.

    PubMed

    Ranjan, Priya; Kao, Yu-Ying; Jiang, Hongying; Joshi, Chandrashekhar P; Harding, Scott A; Tsai, Chung-Jui

    2004-08-01

    A PCR-based suppression subtractive hybridization (SSH) technique was used to identify differentially expressed genes in developing tissues of control and transgenic aspen (Populus tremuloides Michx.) with down-regulated 4CL1 (4-coumarate:coenzyme A ligase) expression and enhanced growth. A total of 11,308 expressed sequence tags (ESTs) representing 5,028 non-redundant transcripts encoding 4,224 unique proteins was obtained from shoot apex, young stem, young leaf and root tip SSH libraries. Putative functions can be assigned to 60% of these transcripts. Approximately 14% of the ESTs are not represented among the 111,000 entries already present in Populus EST databases. In general, ESTs of the metabolism class occurred at a higher frequency in control- than transgenic-enriched libraries of all tissues, whereas protein synthesis and protein fate ESTs were over-represented in meristematic tissues of transgenics where 4CL1 was relatively strongly suppressed. Among all tissues, leaves yielded the highest percentage of ESTs with either unknown protein function or insignificant similarity to other protein/DNA/EST sequences in existing databases. Of particular interest was a large number of ESTs (16%) associated with signal transduction in transgenic leaves. Among these were several leucine-rich-repeat receptor-like protein kinases with markedly elevated expression in transgenic leaves. We also identified homologs of transposable elements that were up-regulated in transgenic tissues, providing the first experimental data for active expression of DNA mobile elements in long-lived tree species.

  17. Polyphenol oxidase and herbivore defense in trembling aspen (Populus tremuloides): cDNA cloning, expression, and potential substrates.

    PubMed

    Haruta, Miyoshi; Pedersen, Jens A.; Constabel, C. Peter

    2001-08-01

    The biochemical anti-herbivore defense of trembling aspen (Populus tremuloides Michx.) was investigated in a molecular analysis of polyphenol oxidase (PPO; EC 1.10.3.2). A PPO cDNA was isolated from a trembling aspen wounded leaf cDNA library and its nucleotide sequence determined. Southern analysis indicated the presence of two PPO genes in the trembling aspen genome. Expression of PPO was found to be induced after herbivory by forest tent caterpillar, by wounding, and by methyl jasmonate treatment. Wound induction was systemic, and occurred in unwounded leaves on wounded plants. This pattern of expression is consistent with a role of this enzyme in insect defense. A search for potential PPO substrates in ethanolic aspen leaf extracts using electron spin resonance (ESR) found no pre-existing diphenolic compounds. However, following a brief delay and several additions of oxygen, an ESR signal specific for catechol was detected. The source of this catechol was most likely the aspen phenolic glycosides tremulacin or salicortin which decomposed during ESR experiments. This was subsequently confirmed in experiments using pure salicortin.

  18. Molecular analysis of herbivore-induced condensed tannin synthesis: cloning and expression of dihydroflavonol reductase from trembling aspen (Populus tremuloides).

    PubMed

    Peters, Darren J; Constabel, C Peter

    2002-12-01

    In order to study condensed tannin synthesis and its induction by herbivory, a dihydroflavonol reductase (DFR) cDNA was isolated from trembling aspen (Populus tremuloides). Bacterial overexpression demonstrated that this cDNA encodes a functional DFR enzyme, and Southern analysis revealed that DFR likely is a single-copy gene in the aspen genome. Aspen plants that were mechanically wounded showed a dramatic increase in DFR expression after 24 h in both wounded leaves and unwounded leaves on wounded trees. Feeding by forest tent caterpillar (Malacosoma disstria) and satin moth (Leucoma salicis) larvae, and treatment with methyl jasmonate, all strongly induced DFR expression. DFR enzyme activity was also induced in wounded aspen leaves, and phytochemical assays revealed that condensed tannin concentrations significantly increased in wounded and systemic leaves. The expression of other genes involved in the phenylpropanoid pathway were also induced by wounding. Our findings suggest that the induction of condensed tannins, compounds known to be important for defense against herbivores, is mediated by increased expression of DFR and other phenylpropanoid genes.

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

    PubMed

    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.

  20. Nutrient concentrations in coarse and fine woody debris of Populus tremuloides Michx.-dominated forests, northern Minnesota, USA

    USGS Publications Warehouse

    Klockow, Paul A.; D'Amato, Anthony W.; Bradford, John B.; Fraver, Shawn

    2014-01-01

    Contemporary forest harvesting practices, specifically harvesting woody biomass as a source of bioenergy feedstock, may remove more woody debris from a site than conventional harvesting. Woody debris, particularly smaller diameter woody debris, plays a key role in maintaining ecosystem nutrient stores following disturbance. Understanding nutrient concentrations within woody debris is necessary for assessing the long-term nutrient balance consequences of altered woody debris retention, particularly in forests slated for use as bioenergy feedstocks. Nutrient concentrations in downed woody debris of various sizes, decay classes, and species were characterized within one such forest type, Populus tremuloides Michx.-dominated forests of northern Minnesota, USA. Nutrient concentrations differed significantly between size and decay classes and generally increased as decay progressed. Fine woody debris (≤ 7.5 cm diameter) had higher nutrient concentrations than coarse woody debris (> 7.5 cm diameter) for all nutrients examined except Na and Mn, and nutrient concentrations varied among species. Concentrations of N, Mn, Al, Fe, and Zn in coarse woody debris increased between one and three orders of magnitude, while K decreased by an order of magnitude with progressing decay. The variations in nutrient concentrations observed here underscore the complexity of woody debris nutrient stores in forested ecosystems and suggest that retaining fine woody debris at harvest may provide a potentially important source of nutrients following intensive removals of bioenergy feedstocks.

  1. Elevated atmospheric CO2 concentration leads to increased whole-plant isoprene emission in hybrid aspen (Populus tremula × Populus tremuloides).

    PubMed

    Sun, Zhihong; Niinemets, Ülo; Hüve, Katja; Rasulov, Bahtijor; Noe, Steffen M

    2013-05-01

    Effects of elevated atmospheric [CO2] on plant isoprene emissions are controversial. Relying on leaf-scale measurements, most models simulating isoprene emissions in future higher [CO2] atmospheres suggest reduced emission fluxes. However, combined effects of elevated [CO2] on leaf area growth, net assimilation and isoprene emission rates have rarely been studied on the canopy scale, but stimulation of leaf area growth may largely compensate for possible [CO2] inhibition reported at the leaf scale. This study tests the hypothesis that stimulated leaf area growth leads to increased canopy isoprene emission rates. We studied the dynamics of canopy growth, and net assimilation and isoprene emission rates in hybrid aspen (Populus tremula × Populus tremuloides) grown under 380 and 780 μmol mol(-1) [CO2]. A theoretical framework based on the Chapman-Richards function to model canopy growth and numerically compare the growth dynamics among ambient and elevated atmospheric [CO2]-grown plants was developed. Plants grown under elevated [CO2] had higher C : N ratio, and greater total leaf area, and canopy net assimilation and isoprene emission rates. During ontogeny, these key canopy characteristics developed faster and stabilized earlier under elevated [CO2]. However, on a leaf area basis, foliage physiological traits remained in a transient state over the whole experiment. These results demonstrate that canopy-scale dynamics importantly complements the leaf-scale processes, and that isoprene emissions may actually increase under higher [CO2] as a result of enhanced leaf area production. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  2. Untangling the effects of root age and tissue nitrogen on root respiration in Populus tremuloides at different nitrogen supply.

    PubMed

    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

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

    PubMed

    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.

  4. Growth and photosynthesis of plants in response to environmental stress. [Raphanus sativus; Glycine max; Salix nigra; Alnus serrulata; Populus tremuloides

    SciTech Connect

    Greitner, C.S.

    1991-01-01

    Environmental stresses generally decrease photosynthetic rates and growth of plants, and alter biomass partitioning. Nutrient deficiency and drought cause root:shoot ratios to increase, whereas the air pollutant ozone (O[sub 3]) causes an opposite shift in carbon allocation. Plants in nature usually grow under suboptimal conditions; therefore plants were raised with O[sub 3] combined with other stresses to analyze the mechanisms whereby multiple stresses influence gas exchange and growth. Physiological and growth responses to stress were determined for radish (raphanus sativus), soybean (Glycine max) willow (Salix nigra), alder (Alnus serrulata) and aspen (Populus tremuloides) in laboratory and field trials. In willow, high-nutrient status plants had more visible injury, but a smaller decline in leaf area with O[sub 3] than did low-nutrient plants. Ultrastructure of host plant cells in alder root nodules was disrupted by O[sub 3], suggesting that this air pollutant can affect the ability of plants to acquire nutrients via symbiosis. Biomass and root:shoot ratios decreased with O[sub 3] in radish and soy-bean. Shifts in stable carbon isotope ratios were caused by O[sub 3], and this technique was used to integrate the effects of O[sub 3] on gas exchange over time. In aspen, O[sub 3] enhanced photosynthesis and foliar areas in young leaves of well-watered aspen, partially compensating for declines in older leaves. This effect was more pronounced in plants raised at a high nitrogen level than in N-deficient plants. Carboxylation efficiency decreased in older, but increased in younger leaves with O[sub 3]. Prior exposure to drought reduced effects of O[sub 3] on photosynthesis and leaf area.

  5. Factors affecting fall down rates of dead aspen (Populus tremuloides) biomass following severe drought in west-central Canada.

    PubMed

    Ted Hogg, Edward H; Michaelian, Michael

    2015-05-01

    Increases in mortality of trembling aspen (Populus tremuloides Michx.) have been recorded across large areas of western North America following recent periods of exceptionally severe drought. The resultant increase in standing, dead tree biomass represents a significant potential source of carbon emissions to the atmosphere, but the timing of emissions is partially driven by dead-wood dynamics which include the fall down and breakage of dead aspen stems. The rate at which dead trees fall to the ground also strongly influences the period over which forest dieback episodes can be detected by aerial surveys or satellite remote sensing observations. Over a 12-year period (2000-2012), we monitored the annual status of 1010 aspen trees that died during and following a severe regional drought within 25 study areas across west-central Canada. Observations of stem fall down and breakage (snapping) were used to estimate woody biomass transfer from standing to downed dead wood as a function of years since tree death. For the region as a whole, we estimated that >80% of standing dead aspen biomass had fallen after 10 years. Overall, the rate of fall down was minimal during the year following stem death, but thereafter fall rates followed a negative exponential equation with k = 0.20 per year. However, there was high between-site variation in the rate of fall down (k = 0.08-0.37 per year). The analysis showed that fall down rates were positively correlated with stand age, site windiness, and the incidence of decay fungi (Phellinus tremulae (Bond.) Bond. and Boris.) and wood-boring insects. These factors are thus likely to influence the rate of carbon emissions from dead trees following periods of climate-related forest die-off episodes. © 2014 Her Majesty the Queen in Right of Canada Global Change Biology © 2014 John Wiley & Sons Ltd Reproduced with the permission of the Minister of Natural Resources Canada.

  6. Impacts of Climate and Insect Defoliators on Trembling Aspen (Populus tremuloides) Mortality and Productivity in Alaskan Boreal Forests

    NASA Astrophysics Data System (ADS)

    Boyd, M. A.; Goetz, S. J.; Rogers, B. M.; Walker, X. J.; Mack, M. C.

    2016-12-01

    Unprecedented rates of climate change have increased tree mortality and growth decline in forested ecosystems worldwide. The boreal forest has experienced a temperature increase of approximately 1.5 º C since 1970, a trend which is expected to continue. In response to the warming and drying of the boreal forest trembling aspen (Populus tremuloides) has experienced recent large-scale die-back. Although die-back is thought to be primarily a result of direct climate changes, insect infestation is another possible driver of aspen mortality and may interact strongly with recent climate. Throughout interior Alaska widespread and consistent foliar damage by the aspen epidermal leaf miner Phyllocnistis populiella has been observed concurrent with some of the warmest and driest growing seasons on record. Here we use tree ring width measurements, tree ring stable carbon isotope signatures, and forest inventory data to study the influence of leaf miner and climate on aspen mortality and productivity decline in the Alaskan boreal forest. In the summer of 2016 we sampled eight Cooperative Alaska Forest Inventory (CAFI) sites established by the US Forest Service in 1994. Since establishment tree status and infestation were recorded every 5 years. Each sampled site was aspen dominated and mortality ranged from 3.5% to 8% within a 5-year sampling period. We collected a total of 24 aspen tree cores and disks from each site: 12 from dead trees and 12 from live trees. In order to assess the influence of leaf miner on radial growth and tree ring stable carbon isotope ratios, cores were also collected from aspen stands surrounding Fairbanks where the size and severity of leaf miner infestation has been recorded since 2003. We expect that prior to mortality trees will show a decline in growth that is correlated to moisture stress and leaf miner infestation. We also expect to see an enriched carbon isotope signal as a result of infestation that will be decoupled from moisture, the

  7. Plant Signals Disrupt (regulate?) Arbuscular Mycorrhizal Fungal Growth Under Enhanced Ozone and CO2 Growing Conditions for Populus tremuloides

    NASA Astrophysics Data System (ADS)

    Miller, R. M.; Podila, G. K.

    2008-12-01

    An understanding of the genetic determinants of keystone symbiotic relationships is essential to elucidating adaptive mechanisms influencing higher-order processes, including shifts in community composition following environmental perturbations. The Aspen FACE project offers a unique opportunity to address adaptive processes with an imposed three way interaction experiment composed of the atmospheric pollutant ozone (eO3), elevated CO2 (eCO2) fumigations, five Populus tremuloides (aspen) genotypes, and both arbuscular mycorrhizal and ectomycorrhizal fungal interactions. The 10 year time span of this experiment has allowed for a realistic and mechanistic understanding of above ground responses of the aspen genotypes to eCO2, eO3 and the interaction effects of eCO2 and eO3. Even so, treatment influences to the below ground, including carbon allocation to roots and associated mycorrhizal symbionts, and rhizosphere dynamics are just beginning to be understood. We hypothesized that mycorrhizal fungal responses to eCO2, eO3, and the interaction effects of eCO2+eO3 are conditioned by the degree of response of their aspen hosts. We intend to describe the molecular mechanisms of an important critical interaction between host and fungus using microarray analysis of expression profiles, as well as metabolic profiling of aspen roots and their associated mycorrhizal partner, the arbuscular mycorrhizal fungus (AMF) Glomus intraradices, under eCO2, eO3 and eCO2+eO3. We present evidence that host-derived factors, expressed in response to eCO2+eO3, trigger responses in Glomus leading to the partitioning or metabolic shift in lipid biosynthesis that is associated with reduced extraradical hyphae growth and altered lipid metabolism. We then scale these lower-level responses to give better insight to fungal intraradical and extraradical allocation of biomass and fungal and root lipid and carbohydrate content in association with aspen genotype responses to the imposed treatments. By

  8. The influence of phosphorus availability and Laccaria bicolor symbiosis on phosphate acquisition, antioxidant enzyme activity, and rhizospheric carbon flux in Populus tremuloides.

    PubMed

    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.

  9. Impacts of greenhouse gases on epicuticular waxes of Populus tremuloides Michx.: results from an open-air exposure and a natural O3 gradient.

    PubMed

    Mankovská, B; Percy, K E; Karnosky, D F

    2005-10-01

    Epicuticular waxes of three trembling aspen (Populus tremuloides Michx.) clones differing in O3 tolerance were examined over six growing seasons (1998-2003) at three bioindicator sites in the Lake States region of the USA and at FACTS II (Aspen FACE) site in Rhinelander, WI. Differences in epicuticular wax structure were determined by scanning electron microscopy and quantified by a coefficient of occlusion. Statistically significant increases in stomatal occlusion occurred for the three O3 bioindicator sites, with the higher O3 sites having the most affected stomata for all three clones as well as for all treatments including elevated CO2, elevated O3, and elevated CO2 + O3. We recorded statistically significant differences between aspen clones and between sampling period (spring, summer, fall). We found no statistically significant differences between treatments or aspen clones in stomatal frequency.

  10. Histochemical and microspectrophotometric analyses of early wound responses of resistant and susceptible Populus tremuloides inoculated with Entoleuca mammata (=Hypoxylon mammatum)

    Treesearch

    B. Bucciarelli; Michael E. Ostry; R. G. Fulcher; N. A. Anderson; C. P. Vance

    1999-01-01

    Stem tissue of resistant and susceptible genotypes of Poyulus tremuloides Michx, wounded or woundinoculated with Entoleuca mammata (Wahlenberg: Fr.) J.D. Rogers & Y.M. Ju was prepared for histochemical and microspectrophotometric analysis. Samples were collected over a 96-h period. Parenchyma cell walls associated with the...

  11. Impact of simulated herbivory on water relations of aspen (Populus tremuloides) seedlings: the role of new tissue in the hydraulic conductivity recovery cycle.

    PubMed

    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.

  12. Intraspecific variation in root and leaf traits and leaf-root trait linkages in eight aspen demes (Populus tremula and P. tremuloides)

    PubMed Central

    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. PMID:24155751

  13. The impact of vessel size on vulnerability curves: data and models for within-species variability in saplings of aspen, Populus tremuloides Michx.

    PubMed

    Cai, Jing; Tyree, Melvin T

    2010-07-01

    The objective of this study was to quantify the relationship between vulnerability to cavitation and vessel diameter within a species. We measured vulnerability curves (VCs: percentage loss hydraulic conductivity versus tension) in aspen stems and measured vessel-size distributions. Measurements were done on seed-grown, 4-month-old aspen (Populus tremuloides Michx) grown in a greenhouse. VCs of stem segments were measured using a centrifuge technique and by a staining technique that allowed a VC to be constructed based on vessel diameter size-classes (D). Vessel-based VCs were also fitted to Weibull cumulative distribution functions (CDF), which provided best-fit values of Weibull CDF constants (c and b) and P(50) = the tension causing 50% loss of hydraulic conductivity. We show that P(50) = 6.166D(-0.3134) (R(2) = 0.995) and that b and 1/c are both linear functions of D with R(2) > 0.95. The results are discussed in terms of models of VCs based on vessel D size-classes and in terms of concepts such as the 'pit area hypothesis' and vessel pathway redundancy.

  14. Effects of Elevated Atmospheric Carbon Dioxide and Tropospheric Ozone on Phytochemical Composition of Trembling Aspen ( Populus tremuloides ) and Paper Birch ( Betula papyrifera ).

    PubMed

    Couture, John J; Meehan, Timothy D; Rubert-Nason, Kennedy F; Lindroth, Richard L

    2017-01-01

    Anthropogenic activities are altering levels of atmospheric carbon dioxide (CO2) and tropospheric ozone (O3). These changes can alter phytochemistry, and in turn, influence ecosystem processes. We assessed the individual and combined effects of elevated CO2 and O3 on the phytochemical composition of two tree species common to early successional, northern temperate forests. Trembling aspen (Populus tremuloides) and paper birch (Betula papyrifera) were grown at the Aspen FACE (Free-Air Carbon dioxide and ozone Enrichment) facility under four combinations of ambient and elevated CO2 and O3. We measured, over three years (2006-08), the effects of CO2 and O3 on a suite of foliar traits known to influence forest functioning. Elevated CO2 had minimal effect on foliar nitrogen and carbohydrate levels in either tree species, and increased synthesis of condensed tannins and fiber in aspen, but not birch. Elevated O3 decreased nitrogen levels in both tree species and increased production of sugar, condensed tannins, fiber, and lignin in aspen, but not birch. The magnitude of responses to elevated CO2 and O3 varied seasonally for both tree species. When co-occurring, CO2 offset most of the changes in foliar chemistry expressed under elevated O3 alone. Our results suggest that levels of CO2 and O3 predicted for the mid-twenty-first century will alter the foliar chemistry of northern temperate forests with likely consequences for forest community and ecosystem dynamics.

  15. PHYTOALEXIN DEFICIENT 4 affects reactive oxygen species metabolism, cell wall and wood properties in hybrid aspen (Populus tremula L. × tremuloides).

    PubMed

    Ślesak, Ireneusz; Szechyńska-Hebda, Magdalena; Fedak, Halina; Sidoruk, Natalia; Dąbrowska-Bronk, Joanna; Witoń, Damian; Rusaczonek, Anna; Antczak, Andrzej; Drożdżek, Michał; Karpińska, Barbara; Karpiński, Stanisław

    2015-07-01

    The phytoalexin deficient 4 (PAD4) gene in Arabidopsis thaliana (AtPAD4) is involved in the regulation of plant--pathogen interactions. The role of PAD4 in woody plants is not known; therefore, we characterized its function in hybrid aspen and its role in reactive oxygen species (ROS)-dependent signalling and wood development. Three independent transgenic lines with different suppression levels of poplar PAD expression were generated. All these lines displayed deregulated ROS metabolism, which was manifested by an increased H2O2 level in the leaves and shoots, and higher activities of manganese superoxide dismutase (MnSOD) and catalase (CAT) in the leaves in comparison to the wild-type plants. However, no changes in non-photochemical quenching (NPQ) between the transgenic lines and wild type were observed in the leaves. Moreover, changes in the ROS metabolism in the pad4 transgenic lines positively correlated with wood formation. A higher rate of cell division, decreased tracheid average size and numbers, and increased cell wall thickness were observed. The results presented here suggest that the Populus tremula × tremuloides PAD gene might be involved in the regulation of cellular ROS homeostasis and in the cell division--cell death balance that is associated with wood development.

  16. Impacts of post-harvest slash and live-tree retention on biomass and nutrient stocks in Populus tremuloides Michx.-dominated forests, northern Minnesota, USA

    USGS Publications Warehouse

    Klockow, Paul A.; D'Amato, Anthony W.; Bradford, John B.

    2013-01-01

    Globally, there is widespread interest in using forest-derived biomass as a source of bioenergy. While conventional timber harvesting generally removes only merchantable tree boles, harvesting biomass feedstock can remove all forms of woody biomass (i.e., live and dead standing woody vegetation, downed woody debris, and stumps) resulting in a greater loss of biomass and nutrients as well as more severe habitat alteration. To investigate the potential impacts of this practice, this study examined the initial impacts (pre- and post-harvest) of various levels of slash and live-tree retention on biomass and nutrient stocks, including carbon (C), nitrogen (N), calcium (Ca), potassium (K), and phosphorus (P), in Populus tremuloides Michx.-dominated forests of northern Minnesota, USA. Treatments examined included three levels of slash retention, whole-tree harvest (WTH), 20% slash retention (20SR), and stem-only harvest (SOH), factored with three levels of green-tree retention, no trees retained (NONE), dispersed retention (DISP), and aggregate retention (AGR). Slash retention was the primary factor affecting post-harvest biomass and nutrient stocks, including woody debris pools. Compared to the unharvested control, stocks of biomass, carbon, and nutrients, including N, Ca, K, and P, in woody debris were higher in all treatments. Stem-only harvests typically contained greater biomass and nutrient stocks than WTH, although biomass and nutrients within 20SR, a level recommended by biomass harvesting guidelines in the US and worldwide, generally did not differ from WTH or SOH. Biomass in smaller-diameter slash material (typically 2.5-22.5 cm in diameter) dominated the woody debris pool following harvest regardless of slash retention level. Trends among treatments in this diameter range were generally similar to those in the total woody debris pool. Specifically, SOH contained significantly greater amounts of biomass than WTH while 20SR was not different from either WTH or

  17. Spring leaf flush in aspen (Populus tremuloides) clones is altered by long-term growth at elevated carbon dioxide and elevated ozone concentration.

    PubMed

    McGrath, Justin M; Karnosky, David F; Ainsworth, Elizabeth A

    2010-04-01

    Early spring leaf out is important to the success of deciduous trees competing for light and space in dense forest plantation canopies. In this study, we investigated spring leaf flush and how long-term growth at elevated carbon dioxide concentration ([CO(2)]) and elevated ozone concentration ([O(3)]) altered leaf area index development in a closed Populus tremuloides (aspen) canopy. This work was done at the Aspen FACE experiment where aspen clones have been grown since 1997 in conditions simulating the [CO(2)] and [O(3)] predicted for approximately 2050. The responses of two clones were compared during the first month of spring leaf out when CO(2) fumigation had begun, but O(3) fumigation had not. Trees in elevated [CO(2)] plots showed a stimulation of leaf area index (36%), while trees in elevated [O(3)] plots had lower leaf area index (-20%). While individual leaf area was not significantly affected by elevated [CO(2)], the photosynthetic operating efficiency of aspen leaves was significantly improved (51%). There were no significant differences in the way that the two aspen clones responded to elevated [CO(2)]; however, the two clones responded differently to long-term growth at elevated [O(3)]. The O(3)-sensitive clone, 42E, had reduced individual leaf area when grown at elevated [O(3)] (-32%), while the tolerant clone, 216, had larger mature leaf area at elevated [O(3)] (46%). These results indicate a clear difference between the two clones in their long-term response to elevated [O(3)], which could affect competition between the clones, and result in altered genotypic composition in future atmospheric conditions.

  18. Will changes in root-zone temperature in boreal spring affect recovery of photosynthesis in Picea mariana and Populus tremuloides in a future climate?

    PubMed

    Fréchette, Emmanuelle; Ensminger, Ingo; Bergeron, Yves; Gessler, Arthur; Berninger, Frank

    2011-11-01

    Future climate will alter the soil cover of mosses and snow depths in the boreal forests of eastern Canada. In field manipulation experiments, we assessed the effects of varying moss and snow depths on the physiology of black spruce (Picea -mariana (Mill.) B.S.P.) and trembling aspen (Populus tremuloides Michx.) in the boreal black spruce forest of western Québec. For 1 year, naturally regenerated 10-year-old spruce and aspen were grown with one of the following treatments: additional N fertilization, addition of sphagnum moss cover, removal of mosses, delayed soil thawing through snow and hay addition, or accelerated soil thawing through springtime snow removal. Treatments that involved the addition of insulating moss or snow in the spring caused lower soil temperature, while removing moss and snow in the spring caused elevated soil temperature and thus had a warming effect. Soil warming treatments were associated with greater temperature variability. Additional soil cover, whether moss or snow, increased the rate of photosynthetic recovery in the spring. Moss and snow removal, on the other hand, had the opposite effect and lowered photosynthetic activity, especially in spruce. Maximal electron transport rate (ETR(max)) was, for spruce, 39.5% lower after moss removal than with moss addition, and 16.3% lower with accelerated thawing than with delayed thawing. Impaired photosynthetic recovery in the absence of insulating moss or snow covers was associated with lower foliar N concentrations. Both species were affected in that way, but trembling aspen generally reacted less strongly to all treatments. Our results indicate that a clear negative response of black spruce to changes in root-zone temperature should be anticipated in a future climate. Reduced moss cover and snow depth could adversely affect the photosynthetic capacities of black spruce, while having only minor effects on trembling aspen.

  19. The responses of Vitreoscilla hemoglobin-expressing hybrid aspen (Populus tremula × tremuloides) exposed to 24-h herbivory: expression of hemoglobin and stress-related genes in exposed and nonorthostichous leaves.

    PubMed

    Sutela, Suvi; Ylioja, Tiina; Jokipii-Lukkari, Soile; Anttila, Anna-Kaisa; Julkunen-Tiitto, Riitta; Niemi, Karoliina; Mölläri, Tiina; Kallio, Pauli T; Häggman, Hely

    2013-11-01

    The responses of transcriptome and phenolic compounds were determined with Populus tremula L. × Populus tremuloides Michx. expressing the hemoglobin (Hb) of Vitreoscilla (VHb) and non-transformant (wt) line. After 24-h exposure of leaves to Conistra vaccinii L., the transcript levels of endogenous non-symbiotic class 1 Hb (PttHb1) and truncated Hb (PttTrHb) genes were modestly reduced and increased, respectively, in both wt and VHb-expressing line. Besides the herbivory exposed leaves showing the most significant transcriptome changes, alterations were also detected in the transcriptome of nonorthostichous leaves positioned directly above the exposed leaves. Both wt and VHb-expressing line displayed similar herbivory-induced effects on gene expression, although the extent of responses was more pronounced in the wt than in the VHb-expressing line. The contents of phenolic compounds were not altered due to herbivory and they were alike in the wt and VHb-expressing line. In addition, we determined the relative growth rates (RGRs) of Orthosia gothica L., Ectropis crepuscularia Denis & Schiff. and Orgyia antiqua L. larvae, and found no variation in the RGRs between the lines. Thus, VHb-expressing P. tremula × tremuloides lines showed to be comparable with wt in regards to the food quality of leaves.

  20. Pre- and Post-Harvest Carbon Dioxide Fluxes from an Upland Boreal Aspen (Populus tremuloides) Forest in Western Boreal Plain, Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Giroux, Kayla

    The Utikuma Region Study Area (URSA) is located in north-central Alberta, Canada, in a region where aspen (Populus tremuloides) dominate the upland vegetation of the Western Boreal Plain Due to the heterogeneity of the surficial geology as well as the sub-humid climate where the water balance is dominated by evapotranspiration, the carbon balance across this landscape is highly variable. Moreover, the upland aspen regions represent significant stores of carbon. More recently, aspen stands have become valuable commercial resources for pulp and paper processing. These stands are harvested through a clear cutting process and are generally left to regenerate on their own, a process which occurs rapidly in clonal species like aspen. Since clonal species establish very quickly following harvest, information on the key ecohydrological controls on stand carbon dioxide (CO2) exchange from the years immediately following harvest are essential to understand the successional trajectory. However, most information currently available on these interactions are obtained several years following a disturbance. Thus, to determine the effects of harvest on aspen regeneration and productivity, ecosystem level fluxes of CO2 three years before and three years after timber harvest were analyzed. Prior to harvest, the ecosystem sequestered 1216 to 1286 g CO2 m-2period-1 over the growing season. Immediately after harvest, the ecosystem became a significant source of CO2 ranging from -874 to -1183 g CO2 m -2period-1, while the second growing season ranged from -233 to -577 g CO2 m-2period-1. The third growing season resulted in a net sink (76 g CO2 m -2period-1) over the same period, but if extrapolated over the whole year, the ecosystem would remain a source of carbon. The magnitude of Gross Ecosystem Productivity (GEP) returned pre-harvest range within two growing seasons. Ecosystem respiration (RE), on the other hand, increased year over year after harvest had taken place

  1. Comparative leaf growth strategies in response to low-water and low-light availability: variation in leaf physiology underlies variation in leaf mass per area in Populus tremuloides.

    PubMed

    Baird, Alec S; Anderegg, Leander D L; Lacey, Melissa E; HilleRisLambers, Janneke; Van Volkenburgh, Elizabeth

    2017-04-04

    Developmental phenotypic plasticity can allow plants to buffer the effects of abiotic and biotic environmental stressors. Therefore, it is vital to improve our understanding of how phenotypic plasticity in ecological functional traits is coordinated with variation in physiological performance in plants. To identify coordinated leaf responses to low-water (LW) versus low-light (LL) availability, we measured leaf mass per area (LMA), leaf anatomical characteristics and leaf gas exchange of juvenile Populus tremuloides Michx. trees. Spongy mesophyll tissue surface area (Asmes/A) was correlated with intrinsic water-use efficiency (WUEi: photosynthesis, (Aarea)/stomatal conductance (gs)). Under LW availability, these changes occurred at the cost of greater leaf tissue density and reduced expansive growth, as leaves were denser but were only 20% the final area of control leaves, resulting in elevated LMA and elevated WUEi. Low light resulted in reduced palisade mesophyll surface area (Apmes/A) while spongy mesophyll surface area was maintained (Asmes/A), with no changes to WUEi. These leaf morphological changes may be a plastic strategy to increase laminar light capture while maintaining WUEi. With reduced density and thickness, however, leaves were 50% the area of control leaves, ultimately resulting in reduced LMA. Our results illustrate that P. tremuloides saplings partially maintain physiological function in response to water and light limitation by inducing developmental plasticity in LMA with underlying anatomical changes. We discuss additional implications of these results in the context of developmental plasticity, growth trade-offs and the ecological impacts of climate change.

  2. Influence of over-expression of the Flowering Promoting Factor 1 gene (FPF1) from Arabidopsis on wood formation in hybrid poplar (Populus tremula L. × P. tremuloides Michx.).

    PubMed

    Hoenicka, Hans; Lautner, Silke; Klingberg, Andreas; Koch, Gerald; El-Sherif, Fadia; Lehnhardt, Denise; Zhang, Bo; Burgert, Ingo; Odermatt, Jürgen; Melzer, Siegbert; Fromm, Jörg; Fladung, Matthias

    2012-02-01

    Constitutive expression of the FPF1 gene in hybrid aspen (Populus tremula L. × P. tremuloides Michx.) showed a strong effect on wood formation but no effect on flowering time. Gene expression studies showed that activity of flowering time genes PtFT1, PtCO2, and PtFUL was not increased in FPF1 transgenic plants. However, the SOC1/TM3 class gene PTM5, which has been related to wood formation and flowering time, showed a strong activity in stems of all transgenic lines studied. Wood density was lower in transgenic plants, despite significantly reduced vessel frequency which was overcompensated by thinner fibre cell walls. Chemical screening of the wood by pyrolysis GC/MS showed that FPF1 transgenics have higher fractions of cellulose and glucomannan products as well as lower lignin content. The latter observation was confirmed by UV microspectrophotometry on a cellular level. Topochemical lignin distribution revealed a slower increase of lignin incorporation in the developing xylem of the transgenics when compared with the wild-type plants. In line with the reduced wood density, micromechanical wood properties such as stiffness and ultimate stress were also significantly reduced in all transgenic lines. Thus, we provide evidence that FPF1 class genes may play a regulatory role in both wood formation and flowering in poplar.

  3. Wood property variation in Populus

    Treesearch

    Dean W. Einspahr; Miles K. Benson; John R. Peckham

    1968-01-01

    The use of bigtooth aspen (Populus grandidentata Michx.), quaking aspen (P. tremuloides Michx.), and cottonwood (P. deltoides Bartr.) by the pulp and paper industry has increased greatly during the past decade. This expanded use has stimulated research on the genetic improvement of Populus. For the past 12 years...

  4. Genetic variation in natural populations of Populus tremuloide

    SciTech Connect

    Cheliak, W.M.

    1980-01-01

    Vegetative reproduction results in a mosaic of clones throughout the extensive natural range of this species. An electrophoretic survey of 26 loci in 222 trees from seven natural populations in Alberta demonstrated great variability. Average observed population heterozygosity was 0.52 with an average of 2.3 alleles per locus; 84% of the loci were polymorphic. A model (for a finite population with neutral alleles) was developed to investigate the effects of partial vegetative reproduction on the amount of variation in a population. Results of the survey conformed to those predicted by the model for a population with a rate of sexual establishment greater than 1/N, where N is the population size. The model states that under these conditions, vegetative reproduction has no effect on the population. Therefore, the high level of observed variation is not an artifact of the mode of natural reproduction. These results support conclusions about high population variability based on phenotypic measurements and also suggest a genetic basis for this variation, rather than simply phenotypic plasticity.

  5. Slow lifelong growth predisposes Populus tremuloides to tree mortality

    Treesearch

    Kathryn B. Ireland; Margaret M. Moore; Peter Z. Fule; Thomas J. Zegler; Robert E. Keane

    2014-01-01

    Widespread dieback of aspen forests, sometimes called sudden aspen decline, has been observed throughout much of western North America, with the highest mortality rates in the southwestern United States. Recent aspen mortality has been linked to drought stress and elevated temperatures characteristic of conditions expected under climate change, but the role of...

  6. Autumnal photosynthesis in short-rotation intensively cultured Populus clones

    Treesearch

    N.D. Nelson; D.I. Dickmann; K.W. Gottschalk

    1982-01-01

    Many exotic hybrid Populus clones grown under short-rotation intensive culture (SRIC) in the Lake States region of the U.S.A. retain green leaves in the autumn for 2-6 weeks after native aspen (P. tremuloides and P. grandidentata) have lost their leaves. Leaves on the terminal shoots of five such clones tested in...

  7. Microsatellite primer resource for Populus developed from

    SciTech Connect

    Yin, Tongming; Yang, Xiaohan; Gunter, Lee E; Tuskan, Gerald A; Wullschleger, Stan D; Huang, Prof. Minren; Li, Shuxian; Zhang, Xinye

    2008-01-01

    In this study, 148 428 simple sequence repeat (SSR) primer pairs were designed from the unambiguously mapped sequence scaffolds of the Nisqually-1 genome. The physical position of the priming sites were identified along each of the 19 Populus chromosomes, and it was specified whether the priming sequences belong to intronic, intergenic, exonic or UTR regions. A subset of 150 SSR loci were amplified and a high amplification success rate (72%) was obtained in P. tremuloides, which belongs to a divergent subgenus of Populus relative to Nisqually-1. PCR reactions showed that the amplification success rate of exonic primer pairs was much higher than that of the intronic/intergenic primer pairs. Applying ANOVA and regression analyses to the flanking sequences of microsatellites, the repeat lengths, the GC contents of the repeats, the repeat motif numbers, the repeat motif length and the base composition of the repeat motif, it was determined that only the base composition of the repeat motif and the repeat motif length significantly affect the microsatellite variability in P. tremuloides samples. The SSR primer resource developed in this study provides a database for selecting highly transferable SSR markers with known physical position in the Populus genome and provides a comprehensive genetic tool to extend the genome sequence of Nisqually-1 to genetic studies in different Populus species.

  8. Expansins in deepwater rice internodes.

    PubMed

    Cho, H T; Kende, H

    1997-04-01

    Cell walls of deepwater rice (Oryza sativa L.) internodes undergo long-term extension (creep) when placed under tension in acidic buffers. This is indicative of the action of the cell wall-loosening protein expansin. Wall extension had a pH optimum of around 4.0 and was abolished by boiling. Acid-induced extension of boiled cell walls could be reconstituted by addition of salt-extracted rice or cucumber cell wall proteins. Cucumber expansin antibody recognized a single protein band of 24.5-kD apparent molecular mass on immunoblots of rice cell wall proteins. Expansins were partially purified by concanavalin A affinity chromatography and sulfopropyl (SP) cation-exchange chromatography. The latter yielded two peaks with extension activity (SP20 and SP29), and immunoblot analysis showed that both of these active fractions contained expansin of 24.5-kD molecular mass. The N-terminal amino acid sequence of SP20 expansin is identical to that deduced from the rice expansin cDNA Os-EXP1. The N-terminal amino acid sequence of SP29 expansin matches that deduced from the rice expansin cDNA Os-EXP2 in six of eight amino acids. Our results show that two expansins occur in the cell walls of rice internodes and that they may mediate acid-induced wall extension.

  9. Agrobacterium-Mediated Stable Genetic Transformation of Populus angustifolia and Populus balsamifera

    PubMed Central

    Maheshwari, Priti; Kovalchuk, Igor

    2016-01-01

    The present study demonstrates Agrobacterium tumefaciens-mediated stable genetic transformation of two species of poplar – Populus angustifolia and Populus balsamifera. The binary vector pCAMBIA-Npro-long-Luc containing the luciferase reporter gene was used to transform stem internode and axillary bud explants. Putative transformants were regenerated on selection-free medium using our previously established in vitro regeneration method. Explant type, genotype, effect of pre-culture, Agrobacterium concentration, a time period of infection and varying periods of co-culture with bacteria were tested for the transformation frequency. The highest frequency of transformation was obtained with stem internode explants pre-cultured for 2 days, infected with Agrobacterium culture at the concentration of OD600 = 0.5 for 10 min and co-cultivated with Agrobacterium for 48 h. Out of the two genotypes tested, P. balsamifera exhibited a higher transformation rate in comparison to P. angustifolia. The primary transformants that exhibited luciferase activity in a bioluminescence assay under the CCD camera when subjected to polymerase chain reaction and Southern blot analysis revealed a stable single-copy integration of luc in their genomes. The reported protocol is highly reproducible and can be applied to other species of poplar; it will also be useful for future genetic engineering of one of the most important families of woody plants for sustainable development. PMID:27014319

  10. Growth responses of Populus tremuloides clones to interacting elevated carbon dioxide and tropospheric ozone

    Treesearch

    J. G. Isebrands; E. P. McDonald; E. Kruger; G. Hendrey; K. Percy; K. Pregitzer; J. Sober; D. F. Karnosky

    2001-01-01

    The Intergovernmental Panel of Climate Change (IPCC) has concluded that the greenhouse gases carbon dioxide (CO2) and tropospheric ozone (O3) are increasing concomitantly globally. Little is known about the effect of these interacting gases on growth, survival, and productivity of forest ecosystems. In this study we assess...

  11. Decline of aspen (Populus tremuloides) in the Interior West [Abstract 1

    Treesearch

    Dale L. Bartos; Robert B Campbell

    1997-01-01

    Western aspen forests are unique because they reproduce primarily by suckering from the parent root system. Generally a disturbance or die back is necessary to stimulate regeneration of the stands. Unlike other tree species, if aspen stands are lost from the landscape, generally they will not return through natural processes. If current conditions continue (e.g., lack...

  12. Growth and mortality of trembling aspen (Populus tremuloides) in response to artificial defoliation

    NASA Astrophysics Data System (ADS)

    Moulinier, Julien; Lorenzetti, François; Bergeron, Yves

    2014-02-01

    To simulate the effects of forest tent caterpillar (FTC) defoliation on trembling aspen growth and mortality, an artificial defoliation experiment was performed over three years in young aspen stands of northwestern Quebec. Defoliation plots of 15 × 15 m were established on three sites, together with associated control stands of pure trembling aspen. In 2007, root collar diameters were measured and positions of all trees were mapped prior defoliation. Severe FTC defoliation was simulated for three successive years (2007-2009) by manually removing all leaves from all but 7-10% of the trees present in the defoliation plots. Yearly surveys of growth and mortality were conducted until 2010 to evaluate defoliation effects on defoliated as well as surrounding undefoliated trees. In absence of other factors, growth and mortality of trembling aspen decreased and increased, respectively, after defoliation. Our study further revealed that small diameter trees died after one year of artificial defoliation, while larger-diameter trees died after repeated defoliations. Distributions of tree mortality tended to be aggregated at small scales (<5 m), corroborating gap patterns observed in mature stands following FTC outbreaks. This experiment revealed that trembling aspen mortality can be directly attributed solely to defoliation. Repeated defoliations during FTC outbreaks have the potential to profoundly modify stand productivity and structure by reducing tree growth and increasing tree mortality in the absence of predisposing factors.

  13. Can elevated CO2 and ozone shift the genetic composition of aspen (Populus tremuloides) stands?

    PubMed

    Moran, Emily V; Kubiske, Mark E

    2013-04-01

    The world's forests are currently exposed to increasing concentrations of carbon dioxide (CO2) and ozone (O3). Both pollutants can potentially exert a selective effect on plant populations. This, in turn, may lead to changes in ecosystem properties, such as carbon sequestration. Here, we report how elevated CO2 and O3 affect the genetic composition of a woody plant population via altered survival. Using data from the Aspen free-air CO2 enrichment (FACE) experiment (in which aspen clones were grown in factorial combinations of CO2 and O3), we develop a hierarchical Bayesian model of survival. We also examine how survival differences between clones could affect pollutant responses in the next generation. Our model predicts that the relative abundance of the tested clones, given equal initial abundance, would shift under either elevated CO2 or O3 as a result of changing survival rates. Survival was strongly affected by between-clone differences in growth responses. Selection could noticeably decrease O3 sensitivity in the next generation, depending on the heritability of growth responses and the distribution of seed production. The response to selection by CO2, however, is likely to be small. Our results suggest that the changing atmospheric composition could shift the genotypic composition and average pollutant responses of tree populations over moderate timescales. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  14. Scale dependence of disease impacts on quaking aspen (Populus tremuloides) mortality in the southwestern United States

    USGS Publications Warehouse

    Bell, David M.; Bradford, John B.; Lauenroth, William K.

    2015-01-01

    By examining variation in disease prevalence, mortality of healthy trees, and mortality of diseased trees, we showed that the role of disease in aspen tree mortality depended on the scale of inference. For variation among individuals in diameter, disease tended to expose intermediate-size trees experiencing moderate risk to greater risk. For spatial variation in summer temperature, disease exposed lower risk populations to greater mortality probabilities, but the magnitude of this exposure depended on summer precipitation. Furthermore, the importance of diameter and slenderness in mediating responses to climate supports the increasing emphasis on trait variation in studies of ecological responses to global change.

  15. Continental-scale assessment of genetic diversity and population structure in quaking aspen (Populus tremuloides)

    Treesearch

    Colin M. Callahan; Carol A. Rowe; Ronald J. Ryel; John D. Shaw; Michael D. Madritch; Karen E. Mock

    2013-01-01

    Aspen populations in the south-western portion of the range are consistent with expectations for a historically stable edge, with low within-population diversity, significant geographical population structuring, and little evidence of northward expansion. Structuring within the southwestern cluster may result from distinct gene pools separated during the Pleistocene...

  16. Time-domain NMR study of the drying of hemicellulose extracted aspen (Populus tremuloides Michx.)

    Treesearch

    Thomas Elder; Carl Houtman

    2013-01-01

    The effect of hot water on aspen chips has been evaluated using time-domain low-field nuclear magnetic resonance (NMR) spectroscopy. At moisture contents above fiber saturation point, treated chips exhibit relaxation times of free water longer than for the control. This is consistent with the removal of hemicelluloses given the hydrophilicity of these polysaccharides....

  17. Internode data communications in a parallel computer

    DOEpatents

    Archer, Charles J; Blocksome, Michael A; Miller, Douglas R; Parker, Jeffrey J; Ratterman, Joseph D; Smith, Brian E

    2014-02-11

    Internode data communications in a parallel computer that includes compute nodes that each include main memory and a messaging unit, the messaging unit including computer memory and coupling compute nodes for data communications, in which, for each compute node at compute node boot time: a messaging unit allocates, in the messaging unit's computer memory, a predefined number of message buffers, each message buffer associated with a process to be initialized on the compute node; receives, prior to initialization of a particular process on the compute node, a data communications message intended for the particular process; and stores the data communications message in the message buffer associated with the particular process. Upon initialization of the particular process, the process establishes a messaging buffer in main memory of the compute node and copies the data communications message from the message buffer of the messaging unit into the message buffer of main memory.

  18. Internode data communications in a parallel computer

    DOEpatents

    Archer, Charles J.; Blocksome, Michael A.; Miller, Douglas R.; Parker, Jeffrey J.; Ratterman, Joseph D.; Smith, Brian E.

    2013-09-03

    Internode data communications in a parallel computer that includes compute nodes that each include main memory and a messaging unit, the messaging unit including computer memory and coupling compute nodes for data communications, in which, for each compute node at compute node boot time: a messaging unit allocates, in the messaging unit's computer memory, a predefined number of message buffers, each message buffer associated with a process to be initialized on the compute node; receives, prior to initialization of a particular process on the compute node, a data communications message intended for the particular process; and stores the data communications message in the message buffer associated with the particular process. Upon initialization of the particular process, the process establishes a messaging buffer in main memory of the compute node and copies the data communications message from the message buffer of the messaging unit into the message buffer of main memory.

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

    PubMed

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

    2015-07-01

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

  20. Contrasting Strategies of Alfalfa Stem Elongation in Response to Fall Dormancy in Early Growth Stage: The Tradeoff between Internode Length and Internode Number

    PubMed Central

    Wang, Zongli; Sun, Qizhong

    2015-01-01

    Fall dormancy (FD) in alfalfa (Medicago sativa L.) can be described using 11 FD ratings, is widely used as an important indicator of stress resistance, productive performance and spring growth. However, the contrasting growth strategies in internode length and internode number in alfalfa cultivars with different FD rating are poorly understood. Here, a growth chamber study was conducted to investigate the effect of FD on plant height, aboveground biomass, internode length, and internode number in alfalfa individuals in the early growth stages. In order to simulate the alfalfa growth environment in the early stage, 11 alfalfa cultivars with FD ratings from one to 11 were chosen and seeded at the greenhouse, and then were transplanted into an artificial growth chamber. The experimental design was a randomized complete block in a split-plot arrangement with three replicates. Plant height, above-ground biomass, internode length, and internode number were measured in early growth stage in all individuals. Our findings showed that plant height and the aboveground biomass of alfalfa did not significantly differ among 11 different FD rated cultivars. Also, internode length and internode number positively affected plant height and the aboveground biomass of alfalfa individuals and the average internode length significantly increased with increasing FD rating. However, internode number tended to sharply decline when the FD rating increased. Moreover, there were no correlations, slightly negative correlations, and strongly negative correlations between internode length and internode number in alfalfa individuals among the three scales, including within-FD ratings, within-FD categories and inter-FD ratings, respectively. Therefore, our results highlighted that contrasting growth strategies in stem elongation were adopted by alfalfa with different FD ratings in the early growth stage. Alfalfa cultivars with a high FD rating have longer internodes, whereas more dormant alfalfa

  1. Carbon Partitioning during Sucrose Accumulation in Sugarcane Internodal Tissue.

    PubMed

    Whittaker, A.; Botha, F. C.

    1997-12-01

    The temporal relationship between sucrose (Suc) accumulation and carbon partitioning was investigated in developing sugarcane internodes. Radiolabeling studies on tissue slices, which contained Suc concentrations ranging from 14 to 42% of the dry mass, indicated that maturation coincided with a redirection of carbon from water-insoluble matter, respiration, amino acids, organic acids, and phosphorylated intermediates into Suc. It is evident that a cycle of Suc synthesis and degradation exists in all of the internodes. The decreased allocation of carbon to respiration coincides with a decreased flux from the hexose pool. Both the glucose and fructose (Fru) concentrations significantly decrease during maturation. The phosphoenolpyruvate, Fru-6-phosphate (Fru-6-P), and Fru-2,6-bisphosphate (Fru-2, 6-P2) concentrations decrease between the young and older internodal tissue, whereas the inorganic phosphate concentration increases. The calculated mass-action ratios indicate that the ATP-dependent phosphofructokinase, pyruvate kinase, and Fru-1,6-bisphosphatase reactions are tightly regulated in all of the internodes, and no evidence was found that major changes in the regulation of any of these enzymes occur. The pyrophosphate-dependent phosphofructokinase reaction is in apparent equilibrium in all the internodes. Substrate availability might be one of the prime factors contributing to the observed decrease in respiration.

  2. Interactions of light and gravity in Chara internodal cells

    NASA Astrophysics Data System (ADS)

    Staves, Mark P.; Whitsit, Kimberly; Yeung, Edward

    2005-08-01

    The "shoots" of Chara corallina are composed of large (ca. 2-5 cm length and 0.5 mm diameter) internodal cells alternating with smaller, node-forming cells. We find that these shoots are both negatively gravitropic as well as positively phototropic. Differential growth in response to both gravity and light typically takes place in the two most apical (youngest) internodal cells, however the plants can be manipulated so that all curvature takes place in a single cell. We grew Chara in aquaria filled with artificial pond water with their rhizoids in 35 mm film canisters containing soil. Thus, it was easy to reorient the axis of the plant with respect to gravity. Experimental plants were allowed to develop to a stage where they had one or two visible internodal cells. In the absence of light, internodal cells are negatively gravitropic. If gravistimulated (horizontal) internodal cells are illuminated with white light from above, gravity and light act together and more rapid curvature ensues. If however, gravistimulated internodal cells are illuminated from below, gravity and light act antagonistically and light can overcome the gravity signal. We find that gravistimulated cells illuminated from below will bend up (i.e. negatively gravitropic and negatively phototropic) at light intensities below ca. 1 μmol m-2 s-1 whereas they curve downward (positively gravitropic and positively phototropic) at higher light intensities. Preliminary studies indicate that both blue and green light stimulate phototropism whereas red light is not effective. Chara thus provides a system in which a single, statolith-free cell responds to both light and gravity and in which the interactions of the light- and gravity-induced signal transduction pathways can be investigated.

  3. Natural Selection and Recombination Rate Variation Shape Nucleotide Polymorphism Across the Genomes of Three Related Populus Species.

    PubMed

    Wang, Jing; Street, Nathaniel R; Scofield, Douglas G; Ingvarsson, Pär K

    2016-03-01

    A central aim of evolutionary genomics is to identify the relative roles that various evolutionary forces have played in generating and shaping genetic variation within and among species. Here we use whole-genome resequencing data to characterize and compare genome-wide patterns of nucleotide polymorphism, site frequency spectrum, and population-scaled recombination rates in three species of Populus: Populus tremula, P. tremuloides, and P. trichocarpa. We find that P. tremuloides has the highest level of genome-wide variation, skewed allele frequencies, and population-scaled recombination rates, whereas P. trichocarpa harbors the lowest. Our findings highlight multiple lines of evidence suggesting that natural selection, due to both purifying and positive selection, has widely shaped patterns of nucleotide polymorphism at linked neutral sites in all three species. Differences in effective population sizes and rates of recombination largely explain the disparate magnitudes and signatures of linked selection that we observe among species. The present work provides the first phylogenetic comparative study on a genome-wide scale in forest trees. This information will also improve our ability to understand how various evolutionary forces have interacted to influence genome evolution among related species.

  4. Chemistry and decomposition of litter from Populus tremuloides Michaux grown at elevated atmospheric CO2and varying N availability

    Treesearch

    John S. King; Kurt S. Pregitzer; Donald R. Zak; Mark E. Kubiske; Jennifer A. Ashby; William E. Holmes

    2001-01-01

    It has been hypothesized that greater production of total nonstructural carbohydrates (TNC) in foliage grown under elevated atmospheric carbon dioxide (CO2) will result in higher concentrations of defensive compounds in tree leaf litter, possibly leading to reduced rates of decomposition and nutrient cycling in forest ecosystems of the future....

  5. The influence of soil type and altered lignin biosynthesis on the physiology, growth and carbon allocation in Populus tremuloides

    Treesearch

    Jessica E. Hancock; Kate L. Bradley; Christian P. Giardina; Kurt S. Pregitzer

    2008-01-01

    Plants influence soil carbon (C) formation through the quality and quantity of C released to soil. Soil type, in turn can modify a plant's influence on soil through effects on plant production, tissue quality and regulation of soil C decomposition and stabilization. Wild-type aspen and three transgenic aspen lines expressing reduced stem lignin concentrations and/...

  6. Scale-dependence of desease impacts on quaking aspen (Populus tremuloides) mortality risk in the southwestern U.S.

    Treesearch

    David M. Bell; John B. Bradford; William K. Lauenroth

    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...

  7. Can elevated CO2 and ozone shift the genetic composition of aspen (Populus tremuloides) stands? New Phytologist

    Treesearch

    Emily V. Moran; Mark E. Kubiske

    2013-01-01

    The world's forests are currently exposed to increasing concentrations of carbon dioxide (CO2) and ozone (O3). Both pollutants can potentially exert a selective effect on plant populations. This, in turn, may lead to changes in ecosystem properties, such as carbon sequestration. Here, we report how elevated CO

  8. Population genetics of Chrysomela tremulae: a first step towards management of transgenic Bacillus thuringiensis poplars Populus tremula x .P. tremuloides.

    PubMed

    Génissel, A; Viard, F; Bourguet, D

    2000-01-01

    Many strategies have been proposed for delaying the development of insect resistance to Bacillus thuringiensis (Bt). The current paradigm for Bt resistance management is the high dose-refuge strategy. For this strategy to be successful: (i) heterozygotes must be killed in treated areas, (ii) resistant alleles must be rare (frequency < 10-3), and (iii) there must be a high level of gene flow between populations to ensure random mating. We studied gene flow within and between populations with a view to managing the resistance of Chrysomela tremulae (Coleoptera: Chrysomelidae) to new transgenic, highly toxic poplars expressing a synthetic Bt gene. In this study, we assessed the extent of gene flow in C. tremulae within and between 16 sites in France and Belgium, using allozyme markers. We found a high level of genetic variability in C. tremulae, with a mean of 0.206 +/- 0.16. There were no obvious limitations to gene flow between populations of C. tremulae over large geographical distances (several hundreds of kilometres). Nevertheless, a very low level of genetic differentiation was observed between a site located in the south of France and the sampled sites from the Centre region.

  9. Early regeneration response to aggregated overstory and harvest residue retention in Populus tremuloides (Michx.)-dominated forests

    Treesearch

    Miranda T. Curzon; Anthony W. D' Amato; Brian J. Palik

    2017-01-01

    Recent emphasis on increasing structural complexity and species diversity reflective of natural ecosystems through the use of retention harvesting approaches is coinciding with increased demand for forest-derived bioenergy feedstocks, largely sourced through the removal of harvest residues associated with whole-tree harvest. Uncertainties about the consequences of such...

  10. Growth, gas exchange, foliar nitrogen content, and water use of subirrigated and overhead irrigated Populus tremuloides Michx. seedlings

    Treesearch

    Anthony S. Davis; Matthew M. Aghai; Jeremiah R. Pinto; Kent G. Apostal

    2011-01-01

    Because limitations on water used by container nurseries has become commonplace, nursery growers will have to improve irrigation management. Subirrigation systems may provide an alternative to overhead irrigation systems by mitigating groundwater pollution and excessive water consumption. Seedling growth, gas exchange, leaf nitrogen (N) content, and water use were...

  11. Association of Pinus banksiana Lamb. and Populus tremuloides Michx. seedling fine roots with Sistotrema brinkmannii (Bres.) J. Erikss. (Basidiomycotina)

    Treesearch

    Lynette R. Potvin; Dana L. Richter; Martin F. Jurgensen; R. Kasten. Dumroese

    2012-01-01

    Sistotrema brinkmannii (Bres.) J. Erikss. (Basidiomycotina, Hydanaceae), commonly regarded as a wood decay fungus, was consistently isolated from bareroot nursery Pinus banksiana Lamb. seedlings. S. brinkmannii was found in ectomycorrhizae formed by Thelephora terrestris Ehrh., ...

  12. Internode or stem unit: a problem of terminology

    Treesearch

    William B. Critchfield

    1985-01-01

    In recent years the term stem unit (SU) has increasingly supplanted internode in the literature of conifer shoot growth, especially since the adoption of SU in a collection of papers titled "Tree Physiology and Yield Improvement" (Cannell and Last 1976). In standard botanical terminology, a node is the point on a stem where one or more lateral appendages (...

  13. Gibberellin biosynthesis and signal transduction is essential for internode elongation in deepwater rice

    PubMed Central

    Ayano, Madoka; Kani, Takahiro; Kojima, Mikiko; Sakakibara, Hitoshi; Kitaoka, Takuya; Kuroha, Takeshi; Angeles-Shim, Rosalyn B; Kitano, Hidemi; Nagai, Keisuke; Ashikari, Motoyuki

    2014-01-01

    Under flooded conditions, the leaves and internodes of deepwater rice can elongate above the water surface to capture oxygen and prevent drowning. Our previous studies showed that three major quantitative trait loci (QTL) regulate deepwater-dependent internode elongation in deepwater rice. In this study, we investigated the age-dependent internode elongation in deepwater rice. We also investigated the relationship between deepwater-dependent internode elongation and the phytohormone gibberellin (GA) by physiological and genetic approach using a QTL pyramiding line (NIL-1 + 3 + 12). Deepwater rice did not show internode elongation before the sixth leaf stage under deepwater condition. Additionally, deepwater-dependent internode elongation occurred on the sixth and seventh internodes during the sixth leaf stage. These results indicate that deepwater rice could not start internode elongation until the sixth leaf stage. Ultra-performance liquid chromatography tandem mass-spectrometry (UPLC-MS/MS) method for the phytohormone contents showed a deepwater-dependent GA1 and GA4 accumulation in deepwater rice. Additionally, a GA inhibitor abolished deepwater-dependent internode elongation in deepwater rice. On the contrary, GA feeding mimicked internode elongation under ordinary growth conditions. However, mutations in GA biosynthesis and signal transduction genes blocked deepwater-dependent internode elongation. These data suggested that GA biosynthesis and signal transduction are essential for deepwater-dependent internode elongation in deepwater rice. Deepwater rice obtained the ability for rapid internode elongation to avoid drowning and adapt to flooded condition. How does it regulate internode elongation? Using both physiological and genetic approach, this paper shows that the plant hormone, gibberellin (GA) regulates internode elongation. PMID:24891164

  14. Dynamics of gene expression during development and expansion of vegetative stem internodes of bioenergy sorghum.

    PubMed

    Kebrom, Tesfamichael H; McKinley, Brian; Mullet, John E

    2017-01-01

    Bioenergy sorghum accumulates 75% of shoot biomass in stem internodes. Grass stem internodes are formed during vegetative growth and elongate in response to developmental and environmental signals. To identify genes and molecular mechanisms that modulate the extent of internode growth, we conducted microscopic and transcriptomic analyses of four successive sub-apical vegetative internodes representing different stages of internode development of the bioenergy sorghum genotype R.07020. Stem internodes of sorghum genotype R.07020 are formed during the vegetative phase and their length is enhanced by environmental signals such as shade and floral induction in short days. During vegetative growth, the first visible and youngest sub-apical internode was ~0.7 cm in length, whereas the fourth fully expanded internode was ~5 cm in length. Microscopic analyses revealed that all internode tissue types including pith parenchyma and vascular bundles are present in the four successive internodes. Growth in the first two sub-apical internodes occurred primarily through an increase in cell number consistent with expression of genes involved in the cell cycle and DNA replication. Growth of the 3rd internode was associated with an increase in cell length and growth cessation in the 4th internode was associated with up-regulation of genes involved in secondary cell wall deposition. The expression of genes involved in hormone metabolism and signaling indicates that GA, BR, and CK activity decreased while ethylene, ABA, and JA increased in the 3rd/4th internodes. While the level of auxin appears to be increasing as indicated by the up-regulation of ARFs, down-regulation of TIR during development indicates that auxin signaling is also modified. The expression patterns of transcription factors are closely associated with their role during the development of the vegetative internodes. Microscopic and transcriptome analyses of four successive sub-apical internodes characterized the

  15. Populus deltoides Bartr ex Marsh.

    Treesearch

    D. T. Cooper

    1980-01-01

    Eastern cottonwood (Populus deltoides), one of the largest eastern hardwoods, is short-lived but the fastest-growing commercial forest species in North America. It grows best on moist well-drained sands or silts near streams, often in pure stands. The lightweight, rather soft wood is used primarily for core stock in manufacturing fumiture and for pulpwood. Eastern...

  16. Lignification in rapidly elongating internodes of deep water rice as a limiting factor in growth

    SciTech Connect

    Sauter, M.; Kende, H. )

    1990-05-01

    Internodes of deep water rice are induced to elongate rapidly by partial submergence, or by treatment with ethylene or gibberellin. This growth response is based, in part, on enhanced cell elongation and an increase in the size of the internodal growing zone. For this to occur, processes that limit growth, e.g. lignification, must be delayed. We examined the activity and distribution of two enzymes of the lignin biosynthetic pathway, phenylalanine ammonia-lyase (PAL) and coniferylalcohol dehydrogenase (CAD) in rapidly growing and control internodes. CAD activity decreased in the rapidly growing region of submerged or gibberellin-treated internodes to about 25% of the activity found in air-grown control internodes. No comparable change in CAD activity was observed in the older, non-growing portions of the internodes. PAL activity changed in similar fashion upon induction of rapid growth.

  17. Internodal myelin volume and axon surface area. A relationship determining myelin thickness?

    PubMed

    Smith, K J; Blakemore, W F; Murray, J A; Patterson, R C

    1982-08-01

    Internodes from normal, remyelinated and regenerated nerve fibres have been isolated from rat spinal roots and sciatic nerve. The internodes have been examined quantitatively by light and electron microscopy to determine their internodal length, myelin thickness, and the circumference and cross-sectional area of both the axons and fibre. Comparison of these measurements of the axon and myelin sheath has revealed a close relationship between the volume of myelin comprising the internode and the area over which the Schwann cell and axon are in close proximity, i.e. the surface area of the axolemma beneath the internodal myelin sheath. The same relationship described not only the internodes on normal nerve fibres, where internodal length is proportional to axon diameter, but also the short and thinly myelinated internodes formed in the adult animal on remyelinated and on regenerated axons. Examination of data presented by Berthold (1978) revealed that a closely similar relationship is also present in feline nerve fibres. In view of the constancy of the relationship between such different types of internode it is suggested that the regulation of myelin volume, and thereby of myelin thickness, may be mediated via the area of the axolemma or of the Schwann cell membrane beneath the myelin sheath.

  18. Changes in myelin sheath thickness and internode geometry in the rabbit phrenic nerve during growth.

    PubMed Central

    Friede, R L; Brzoska, J; Hartmann, U

    1985-01-01

    The rabbit phrenic nerve was studied at seven phases of growth from the newborn to the adult to determine the length of the nerve fibres, the length of the internodes, the fibre calibre, the geometric proportions of the internodes and the thickness of the myelin sheaths. The elongation of the internodes corresponded precisely to the elongation of the nerve, indicating a constant number of approximately 140 internodes per fibre, each internode elongating commensurate with body growth. Internode elongation was accompanied by increases in fibre calibre, but these parameters did not change in precise proportion. The internodes of thick fibres were relatively short for calibre, as defined by the length/diameter quotient. This trend of foreshortening changed during growth. Sheath thickness, defined by the quotient axon diameter/fibre diameter, was determined with a computer-assisted method. Fibres of young rabbits had relatively thin sheaths for axon calibre, compared with adult rabbits. The changes in sheath thickness corresponded to the changes in internode geometry. This was consistent with previous studies showing that elongation or foreshortening of an internode of a given calibre has a slight, but definite effect on the thickness of its myelin sheath. PMID:3870716

  19. Expression of lipoxygenase during organogenic nodule formation from hop internodes.

    PubMed

    Fortes, Ana Margarida; Coronado, Maria José; Testillano, Pilar S; Risueño, Maria del Carmen; Pais, Maria Salomé

    2004-02-01

    Study of lipoxygenase expression (LOX; EC 1.13.11.12) during organogenic nodule formation in hop (Humulus lupulus var. Nugget) showed that LOXs are developmentally regulated throughout the process, suggesting their involvement in the response of internodes to wounding, nodule formation, and plantlet regeneration from these nodules. LOX activity and lipid peroxides exhibited a huge increase during the first week of culture, which may indicate a role for LOX and LOX products in response to wounding in hop, as reported for other systems. Western blotting analysis showed a de novo synthesis of LOX isoenzymes in response to wounding and the detection of three different isoenzymes. Confocal analysis of LOX immunofluorescence revealed the presence of the enzyme in cortical cells of induced internodes and in prenodular cells, mostly appearing as cytoplasmic spots. Some of them were identified as lipid bodies by cytochemical and double immunofluorescence assays, suggesting the involvement of a lipid body LOX during nodule formation. Immunogold labeling detected LOX in peroxisomes, lipid bodies, and plastids of nodular cells. Quantification of the labeling density provided statistical significance for the localization of LOX (three different isoenzymes) in the three compartments, which suggested a possible involvement of LOX in metabolic functions of these organelles during organogenic nodule formation and plantlet regeneration.

  20. Proteomics of Leaf Tissues from Populus

    SciTech Connect

    Hurst, Gregory {Greg} B; Yang, Xiaohan; Tschaplinski, Timothy J; Tuskan, Gerald A; Lankford, Patricia K; Shah, Manesh B; Jawdy, Sara; Gunter, Lee E; Engle, Nancy L

    2010-01-01

    Trees of the genus Populus are farmed commercially for wood and fiber, and are a potential bioenergy crop. As a scientific model organism, P. trichocarpa was the first forest tree for which the genome sequence has been determined. Knowledge of the Populus proteome will provide a deeper understanding of gene expression patterns in various tissues of the plant. To build on our previous profile of the proteome of xylem tissue in Populus (Kalluri et al., Proteomics 2009, 9, 4871), we are currently developing methods for studying the proteome of Populus leaves.

  1. Profile based image analysis for identification of chopped biomass stem nodes and internodes

    USDA-ARS?s Scientific Manuscript database

    Because of their significant variation in chemical composition, segregation of chopped biomass into nodes and internodes helps in efficient utilization of these feedstocks. Stem internodes having low ash content are a better feedstock for bioenergy and biofuel applications than nodes. However, separ...

  2. Etiology of bronze leaf disease of Populus

    Treesearch

    Jason A. Smith; R. A. Blanchette; M. E. Ostry; N. A. Anderson

    2002-01-01

    Bronze leaf disease is a potentially destructive disorder of the Populus section of the genus Populus. The causal agent has been reported to be Apioplagiostoma populi (anarnorph: Discula sp.). Based on etiological and symptomological studies, field observations of symptom development suggest that the pathogen...

  3. Prototype wood chunker used on Populus 'Tristis'

    Treesearch

    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...

  4. Clone history shapes Populus drought responses.

    PubMed

    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.

  5. Circadian Clock Components Regulate Entry and Affect Exit of Seasonal Dormancy as Well as Winter Hardiness in Populus Trees1[W][OA

    PubMed Central

    Ibáñez, Cristian; Kozarewa, Iwanka; Johansson, Mikael; Ögren, Erling; Rohde, Antje; Eriksson, Maria E.

    2010-01-01

    This study addresses the role of the circadian clock in the seasonal growth cycle of trees: growth cessation, bud set, freezing tolerance, and bud burst. Populus tremula × Populus tremuloides (Ptt) LATE ELONGATED HYPOCOTYL1 (PttLHY1), PttLHY2, and TIMING OF CAB EXPRESSION1 constitute regulatory clock components because down-regulation by RNA interference of these genes leads to altered phase and period of clock-controlled gene expression as compared to the wild type. Also, both RNA interference lines show about 1-h-shorter critical daylength for growth cessation as compared to the wild type, extending their period of growth. During winter dormancy, when the diurnal variation in clock gene expression stops altogether, down-regulation of PttLHY1 and PttLHY2 expression compromises freezing tolerance and the expression of C-REPEAT BINDING FACTOR1, suggesting a role of these genes in cold hardiness. Moreover, down-regulation of PttLHY1 and PttLHY2 causes a delay in bud burst. This evidence shows that in addition to a role in daylength-controlled processes, PttLHY plays a role in the temperature-dependent processes of dormancy in Populus such as cold hardiness and bud burst. PMID:20530613

  6. Action currents, internodal potentials, and extracellular records of myelinated mammalian nerve fibers derived from node potentials.

    PubMed Central

    Marks, W B; Loeb, G E

    1976-01-01

    The potential distribution within the internodal axon of mammalian nerve fibers is derived by applying known node potential waveforms to the ends of an equivalent circuit model of the internode. The complete spatial/temporal profile of action potentials synthesized from the internodal profiles is used to compute the node current waveforn, and the extracellular action potential around fibers captured within a tubular electrode. For amphibia, the results agreed with empirical values. For mammals, the amplitude of the node currents plotted against conduction velocity was fitted by a straight line. The extracellular potential waveform depended on the location of the nodes within the tube. For tubes of length from 2 to 8 internodes, extracellular wave amplitude (mammals) was about one-third of the product of peak node current and tube resistance (center to ends). The extracellular potentials developed by longitudinal and radial currents in an anisotropic medium (fiber bundle) are compared. PMID:1276389

  7. Detailed Analysis of Wheat Straw Node and Internode for their Prospective Efficient Utilisation.

    PubMed

    Ghaffar, Seyed Hamidreza; Fan, Mizi; Zhou, Yonghui; AboMadyan, Omar

    2017-09-27

    In order to efficiently utilise wheat straw, the systematic examination of their cell wall components, chemical structures, morphology and relation to the physicochemical and mechanical properties is necessary. Detailing of node and internode signifies their different features and characteristics which can ultimately lead to their separated processing for enhanced efficiency and higher added-value bio-refinery. In this study, distinct variations were found amongst characteristics of node and internode, inner and outer surface. It was revealed that node has more extractives, Klason lignin and ash content than internode, higher contents of extractives and ash in the node are related to the thicker epidermis tissue. Hot-water followed by mild steam pre-treatment was used to examine the effects on the characteristics of wheat straw. The results showed: 1) reduced level of waxes and Si (weight %) from the outer surface, and 2) significantly lower (P < 0.05) extractives content in both internode and node.

  8. The Significance of Internode Length for Saltatory Conduction: Looking Back at the Age of 90.

    PubMed

    Friede, Reinhard L

    2017-03-14

    The development of peripheral nerve fibers involves interdependence between the timing of Schwann cell recruitment during myelination and elongation of the nerve. This adjusts the number and the length of internodes to the length of the fiber. Saltatory conduction in longer nerves involves longer saltations; this makes internode length the factor that determines conduction velocity, thereby adjusting impulse transmission in circuits of different lengths. Myelination increases conduction velocity by means of saltatory conduction but what determines the saltatory conduction is not so much the indispensable insulating adjunct of myelin as the length of the internodes that separate the excitable membrane segments. We have previously studied the development of the length and proportion of internodes in some detail. If the anatomical data are combined, the data fall in place for a revised understanding of conduction velocity and the system that adapts the conduction properties of peripheral nerves to fiber lengths and to body size.

  9. Plasmalogen phospholipids protect internodal myelin from oxidative damage.

    PubMed

    Luoma, Adrienne M; Kuo, Fonghsu; Cakici, Ozgur; Crowther, Michelle N; Denninger, Andrew R; Avila, Robin L; Brites, Pedro; Kirschner, Daniel A

    2015-07-01

    Reactive oxygen species (ROS) are implicated in a range of degenerative conditions, including aging, neurodegenerative diseases, and neurological disorders. Myelin is a lipid-rich multilamellar sheath that facilitates rapid nerve conduction in vertebrates. Given the high energetic demands and low antioxidant capacity of the cells that elaborate the sheaths, myelin is considered intrinsically vulnerable to oxidative damage, raising the question whether additional mechanisms prevent structural damage. We characterized the structural and biochemical basis of ROS-mediated myelin damage in murine tissues from both central nervous system (CNS) and peripheral nervous system (PNS). To determine whether ROS can cause structural damage to the internodal myelin, whole sciatic and optic nerves were incubated ex vivo with a hydroxyl radical-generating system consisting of copper (Cu), hydrogen peroxide (HP), and ortho-phenanthroline (OP). Quantitative assessment of unfixed tissue by X-ray diffraction revealed irreversible compaction of myelin membrane stacking in both sciatic and optic nerves. Incubation in the presence of the hydroxyl radical scavenger sodium formate prevented this damage, implicating hydroxyl radical species. Myelin membranes are particularly enriched in plasmalogens, a class of ether-linked phospholipids proposed to have antioxidant properties. Myelin in sciatic nerve from plasmalogen-deficient (Pex7 knockout) mice was significantly more vulnerable to Cu/OP/HP-mediated ROS-induced compaction than myelin from WT mice. Our results directly support the role of plasmalogens as endogenous antioxidants providing a defense that protects ROS-vulnerable myelin. Copyright © 2015 Elsevier Inc. All rights reserved.

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

    PubMed

    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. © The Author 2014. Published by Oxford University Press. All rights reserved

  11. Strigolactones Stimulate Internode Elongation Independently of Gibberellins1[C][W

    PubMed Central

    de Saint Germain, Alexandre; Ligerot, Yasmine; Dun, Elizabeth A.; Pillot, Jean-Paul; Ross, John J.; Beveridge, Christine A.; Rameau, Catherine

    2013-01-01

    Strigolactone (SL) mutants in diverse species show reduced stature in addition to their extensive branching. Here, we show that this dwarfism in pea (Pisum sativum) is not attributable to the strong branching of the mutants. The continuous supply of the synthetic SL GR24 via the root system using hydroponics can restore internode length of the SL-deficient rms1 mutant but not of the SL-response rms4 mutant, indicating that SLs stimulate internode elongation via RMS4. Cytological analysis of internode epidermal cells indicates that SLs control cell number but not cell length, suggesting that SL may affect stem elongation by stimulating cell division. Consequently, SLs can repress (in axillary buds) or promote (in the stem) cell division in a tissue-dependent manner. Because gibberellins (GAs) increase internode length by affecting both cell division and cell length, we tested if SLs stimulate internode elongation by affecting GA metabolism or signaling. Genetic analyses using SL-deficient and GA-deficient or DELLA-deficient double mutants, together with molecular and physiological approaches, suggest that SLs act independently from GAs to stimulate internode elongation. PMID:23943865

  12. Energy Values of Nine Populus Clones

    Treesearch

    Terry F. Strong

    1980-01-01

    Compares calorific values for components of nine Populus clones. The components include stem wood, stem bark, and branches. Also compares calorific values for clones of balsam poplar and black cottonwood parentages.

  13. Differential interspecific incompatibility in Populus breeding

    Treesearch

    A. Assibi Mahama; Ronald S., Jr. Zalesny; Richard B. Hall

    2006-01-01

    Interspecific hybrids of Populus are valuable in tree production systems. Hybrid vigor is achieved for various traits and is useful for transferring disease and pest resistance. Incompatibility, however, sometimes precludes such combinations.

  14. Wood properties of Populus and Betula in long-term exposure to elevated CO₂ and O₃.

    PubMed

    Kostiainen, Katri; Saranpää, Pekka; Lundqvist, Sven-Olof; Kubiske, Mark E; Vapaavuori, Elina

    2014-06-01

    We studied the interactive effects of elevated concentrations of CO2 and O3 on radial growth and wood properties of four trembling aspen (Populus tremuloides Michx.) clones and paper birch (Betula papyrifera Marsh.) saplings. The material for the study was collected from the Aspen FACE (free-air CO2 enrichment) experiment in Rhinelander (WI, USA). Trees had been exposed to four treatments [control, elevated CO2 (560 ppm), elevated O3 (1.5 times ambient) and combined CO2 + O3 ] during growing seasons 1998-2008. Most treatment responses were observed in the early phase of experiment. Our results show that the CO2- and O3-exposed aspen trees displayed a differential balance between efficiency and safety of water transport. Under elevated CO2, radial growth was enhanced and the trees had fewer but hydraulically more efficient larger diameter vessels. In contrast, elevated O3 decreased radial growth and the diameters of vessels and fibres. Clone-specific decrease in wood density and cell wall thickness was observed under elevated CO2 . In birch, the treatments had no major impacts on wood anatomy or wood density. Our study indicates that short-term impact studies conducted with young seedlings may not give a realistic view of long-term ecosystem responses.

  15. Clone history shapes Populus drought responses

    PubMed Central

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

    2011-01-01

    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. PMID:21746919

  16. Relationship between myelin sheath diameter and internodal length in axons of the anterior medullary velum of the adult rat.

    PubMed

    Ibrahim, M; Butt, A M; Berry, M

    1995-11-01

    Relations between myelin sheath diameters and internodal lengths were measured in whole mounts of osmium stained intact anterior medullary velum (AMV) from glutaraldehyde perfused adult rats. The AMV is a sheet of CNS tissue which roofs the IVth ventricle and contains fascicles of myelinated fibres which arise mainly from the nucleus of the IVth cranial nerve. These fibers displayed a broad range of myelin sheath external diameters and internodal lengths, from < 1-12 microns and 50-750 microns, respectively. Myelin sheath external diameter was a measurement of the axonal diameter plus the thickness of its myelin sheath, while internodal length was measured as the distance between consecutive nodes. There was a broadly linear relationship between myelin sheath diameters and internodal lengths, with the smaller diameter sheaths tending to have shorter internodes than the larger. However, the correlation was weak and for any given diameter myelin sheaths displayed considerable variation in their internodal lengths. The smallest diameter myelin sheaths, < 4 microns, consistently had shorter internodes than predicted by a linear regression and, in an analysis of consecutive internodes in single fibres, the slope was flattened in fibres with a diameter > 4 microns. Our results indicated that small and large calibre fibres may have different myelin sheath diameter-internodal length interrelations.

  17. Transcriptome analysis of genes involved in secondary cell wall biosynthesis in developing internodes of Miscanthus lutarioriparius.

    PubMed

    Hu, Ruibo; Xu, Yan; Yu, Changjiang; He, Kang; Tang, Qi; Jia, Chunlin; He, Guo; Wang, Xiaoyu; Kong, Yingzhen; Zhou, Gongke

    2017-08-22

    Miscanthus is a promising lignocellulosic bioenergy crop for bioethanol production. To identify candidate genes and regulation networks involved in secondary cell wall (SCW) development in Miscanthus, we performed de novo transcriptome analysis of a developing internode. According to the histological and in-situ histochemical analysis, an elongating internode of M. lutarioriparius can be divided into three distinct segments, the upper internode (UI), middle internode (MI) and basal internode (BI), each representing a different stage of SCW development. The transcriptome analysis generated approximately 300 million clean reads, which were de novo assembled into 79,705 unigenes. Nearly 65% of unigenes was annotated in seven public databases. Comparative profiling among the UI, MI and BI revealed four distinct clusters. Moreover, detailed expression profiling was analyzed for gene families and transcription factors (TFs) involved in SCW biosynthesis, assembly and modification. Based on the co-expression patterns, putative regulatory networks between TFs and SCW-associated genes were constructed. The work provided the first transcriptome analysis of SCW development in M. lutarioriparius. The results obtained provide novel insights into the biosynthesis and regulation of SCW in Miscanthus. In addition, the genes identified represent good candidates for further functional studies to unravel their roles in SCW biosynthesis and modification.

  18. Burial depth and stolon internode length independently affect survival of small clonal fragments.

    PubMed

    Dong, Bi-Cheng; Liu, Rui-Hua; Zhang, Qian; Li, Hong-Li; Zhang, Ming-Xiang; Lei, Guang-Chun; Yu, Fei-Hai

    2011-01-01

    Disturbance can fragment plant clones into different sizes and unstabilize soils to different degrees, so that clonal fragments of different sizes can be buried in soils at different depths. As a short-term storage organ, solon internode may help fragmented clones of stoloniferous plants to withstand deeper burial in soils. We address (1) whether burial in soils decreases survival and growth of small clonal fragments, and (2) whether increasing internode length increases survival and growth of small fragments under burial. We conducted an experiment with the stoloniferous, invasive herb Alternanthera philoxeroides, in which single-node fragments with stolon internode of 0, 2, 4 and 8 cm were buried in soils at 0, 2, 4 and 8 cm depth, respectively. Increasing burial depth significantly reduced survival of the A. philoxeroides plants and increased root to shoot ratio and total stolon length, but did not change growth measures. Increasing internode length significantly increased survival and growth measures, but there was no interaction effect with burial depth on any traits measured. These results indicate that reserves stored in stolon internodes can contribute to the fitness of the A. philoxeroides plants subject to disturbance. Although burial reduced the regeneration capacity of the A. philoxeroides plants, the species may maintain the fitness by changing biomass allocation and stolon length once it survived the burial. Such responses may play an important role for A. philoxeroides in establishment and invasiveness in frequently disturbed habitats.

  19. Water relations of populus clones

    SciTech Connect

    Pallardy, S.G.; Kozlowski, T.T.

    1981-02-01

    Stomatal aperture and water balance in the field of eight Populus clones varying in growth rate were closely related to environmental factors and clonal differences were clearly expressed. Leaf water potential (psi) was influenced by solar radiation, leaf conductance, evaporative demand, and soil moisture content. The effects of soil moisture on psi were greatly modified by atmospheric conditions and stomatal conductance. Several slow-growing clones exhibited extended periods of psi below that of rapidly growing clones, despite high evaporative demand and the much greater transpiring surfaces of the fast-growing clones. Stomata of all clones responded to changes in light intensity and vapor pressure gradient (VPG). Pronounced stomatal sensitivity to VPG of two rapidly growing clones of common parentage, and the resultant capacity of these clones to moderate water deficits under high evaporative demand, were associated with drought resistance in one of the parents. Seasonal maximum leaf conductance was positively related to growth in several clones, suggesting that rapidly growing clones possess the capacity to carry on higher rates of gas exchange under favorable conditions. Analysis of changes in psi with changes in transpirational flux density (TFD) showed that for four clones, psi change per unit change in TFD decreased as TFD increased, indicating plant adaptation for prevention of damaging psi even at high TFD. More rapidly growing clones exhibited a larger initial rate of decline in psi with TFD, but reduced the rate of decline more than slow-growing clones as TFD increased. (Refs. 41).

  20. First report of the Armillaria root disease pathogen, Armillaria sinapina, on subalpine fir (Abies lasiocarpa) and quaking aspen (Populus tremuloides) in Colorado

    Treesearch

    K. S. Burns; J. W. Hanna; Ned Klopfenstein; M.-S. Kim

    2016-01-01

    In July 2014, mycelial fans (isolates CO104F, CO106F, and CO108F) of Armillaria sp. were collected from forest trees in Colorado. These isolates were all identified as A. sinapina based on a somatic pairing test against 18 tester isolates representing six North American Armillaria spp. and nucleotide sequences of the translation elongation factor 1alpha (tef-...

  1. ptr-MIR169 is a posttranscriptional repressor of PtrHAP2 during vegetative bud dormancy period of aspen (Populus tremuloides) trees

    SciTech Connect

    Potkar, Rewati; Recla, Jill; Busov, Victor

    2013-02-15

    Highlights: ► We show a novel microRNA-mediated mechanism for control of bud dormancy in trees. ► ptr-MIR169a and PtrHAP2–5 gene showed inverse expression during dormancy period. ► The PtrHAP2–5 decline in abundance correlated with high ptr-MIR169a levels. ► PtrHAP2–5 cleavage occurred at the miR169 site during PtrHAP2–5 transcript decline. ► Our results show that miR169 attenuates PtrHAP2–5 transcript during dormancy. -- Abstract: Dormancy is a mechanism evolved in woody perennial plants to survive the winter freezing and dehydration stress via temporary suspension of growth. We have identified two aspen microRNAs (ptr-MIR169a and ptr-MIR169h) which were highly and specifically expressed in dormant floral and vegetative buds. ptr-MIR169a and its target gene PtrHAP2–5 showed inverse expression patterns during the dormancy period. ptr-MIR169a transcript steadily increased through the first half of the dormancy period and gradually declined with the approach of active growing season. PtrHAP2–5 abundance was higher in the beginning of the dormancy period but rapidly declined thereafter. The decline of PtrHAP2–5 correlated with the high levels of ptr-MIR169a accumulation, suggesting miR169-mediated attenuation of the target PtrHAP2–5 transcript. We experimentally verified the cleavage of PtrHAP2–5 at the predicted miR169a site at the time when PtrHAP2–5 transcript decline was observed. HAP2 is a subunit of a nuclear transcription factor Y (NF-Y) complex consisting of two other units, HAP3 and HAP5. Using digital expression profiling we show that poplar HAP2 and HAP5 are preferentially detected in dormant tissues. Our study shows that microRNAs play a significant and as of yet unknown and unstudied role in regulating the timing of bud dormancy in trees.

  2. Impact of simulated herbivory on water relations of aspen (Populus tremuloides) seedlings: the role of new tissue in the hydraulic conductivity recovery cycle

    Treesearch

    David A. Galvez; M.T. Tyree

    2009-01-01

    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...

  3. ptr-MIR169 is a posttranscriptional repressor of PtrHAP2 during vegetative bud dormancy period of aspen (Populus tremuloides) trees.

    PubMed

    Potkar, Rewati; Recla, Jill; Busov, Victor

    2013-02-15

    Dormancy is a mechanism evolved in woody perennial plants to survive the winter freezing and dehydration stress via temporary suspension of growth. We have identified two aspen microRNAs (ptr-MIR169a and ptr-MIR169h) which were highly and specifically expressed in dormant floral and vegetative buds. ptr-MIR169a and its target gene PtrHAP2-5 showed inverse expression patterns during the dormancy period. ptr-MIR169a transcript steadily increased through the first half of the dormancy period and gradually declined with the approach of active growing season. PtrHAP2-5 abundance was higher in the beginning of the dormancy period but rapidly declined thereafter. The decline of PtrHAP2-5 correlated with the high levels of ptr-MIR169a accumulation, suggesting miR169-mediated attenuation of the target PtrHAP2-5 transcript. We experimentally verified the cleavage of PtrHAP2-5 at the predicted miR169a site at the time when PtrHAP2-5 transcript decline was observed. HAP2 is a subunit of a nuclear transcription factor Y (NF-Y) complex consisting of two other units, HAP3 and HAP5. Using digital expression profiling we show that poplar HAP2 and HAP5 are preferentially detected in dormant tissues. Our study shows that microRNAs play a significant and as of yet unknown and unstudied role in regulating the timing of bud dormancy in trees. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. The role of nodal and internodal responses in gravitropism and autotropism in Galium aparine L

    NASA Technical Reports Server (NTRS)

    Heathcote, D. G.; Brown, A. H. (Principal Investigator)

    1987-01-01

    This time course and location of gravitropically induced curvatures in stems of goosegrass (Gallium aparine L.), a member of the Rubiaceae, have been investigated. In the early stages of the response (0-5 h), curvature develops throughout the growing region, and is followed by an autotropic straightening which affects the internodes only, leading to the production of essentially straight internodes some 15 h after the onset of gravistimulation. Curvatures developing in the nodal regions, however, continue to increase over this period, and are not subject to reversal by autotropism. The nodal curvatures are not entirely dependent on the presence of any other part of the plant, since marked curvatures can be induced in isolated nodal segments. This pattern of response leads ultimately to correction of the growth direction of the plant by means of curvature responses confined exclusively to the nodes, despite the initial participation of both nodes and internodes in the gravitropic reaction.

  5. Comparative studies on hydrothermal pretreatment and enzymatic saccharification of leaves and internodes of alamo switchgrass.

    PubMed

    Hu, Zhoujian; Foston, Marcus; Ragauskas, Arthur J

    2011-07-01

    Hydrothermal pretreatment was performed on the leaves and internodes portions of Alamo switchgrass, Panicum virgatum L., to enhance the digestibility of cellulose towards cellulase. It was observed that extractives free leaves portion provided 18.1% lower pretreatment gravimetrical yield and 33.8% greater cellulose-to-glucose yield than internodes portion. The degree of polymerization (DP) and ultrastructure of cellulose were determined by gel-permeation chromatography and solid-state cross polarization/magic angle spinning (13)C NMR experiments. The results suggested that hydrothermal pretreatment hydrolyzed amorphous cellulose and yielded a product enriched in paracrystalline cellulose. Furthermore, the DP of cellulose was reduced to one third of the origin value after hydrothermal pretreatment. The resulting biomass after pretreatment for leaves and internodes has similar cellulose ultrastructure and chemical profiles. The results of the enzymatic hydrolysis studies of cellulose suggest that the reduced DP of cellulose of pretreated switchgrass was an important factor influencing the enhanced digestibility of pretreated switchgrass.

  6. Metabolomics study of Populus type propolis.

    PubMed

    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.

  7. Epigenomics of Development in Populus

    SciTech Connect

    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

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

    PubMed

    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.

  9. Identification of nodes and internodes of chopped biomass stems by Image analysis using profile curvature and slope

    USDA-ARS?s Scientific Manuscript database

    Morphological components of biomass stems vary in their chemical composition and they can be better utilized when processed after segregation. Within the stem, nodes and internodes have significantly different compositions. The internodes have low ash content and are a better feedstock for bioenergy...

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

    NASA Astrophysics Data System (ADS)

    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.; Déjardin, A.; dePamphilis, C.; Detter, J.; Dirks, B.; Dubchak, I.; Duplessis, S.; Ehlting, 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.; Kangasjärvi, J.; Karlsson, J.; Kelleher, C.; Kirkpatrick, R.; Kirst, M.; Kohler, A.; Kalluri, U.; Larimer, F.; Leebens-Mack, J.; Leplé, J.-C.; Locascio, P.; Lou, Y.; Lucas, S.; Martin, F.; Montanini, B.; Napoli, C.; Nelson, D. R.; Nelson, C.; Nieminen, K.; Nilsson, O.; Pereda, V.; Peter, G.; Philippe, R.; Pilate, G.; Poliakov, A.; Razumovskaya, J.; Richardson, P.; Rinaldi, C.; Ritland, K.; Rouzé, P.; Ryaboy, D.; Schmutz, J.; Schrader, J.; Segerman, B.; Shin, H.; Siddiqui, A.; Sterky, F.; Terry, A.; Tsai, C.-J.; Uberbacher, E.; Unneberg, P.; Vahala, J.; Wall, K.; Wessler, S.; Yang, G.; Yin, T.; Douglas, C.; Marra, M.; Sandberg, G.; Van de 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. 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.

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

    SciTech Connect

    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.

  12. Insertional mutagenesis in Populus: relevance and feasibility

    Treesearch

    Victor Busov; Matthias Fladung; Andrew Groover; Steven Strauss

    2005-01-01

    The recent sequencing of the first tree genome, that of the black cottonwood (Populus trichocarpa), opens a new chapter in tree functional genomics. While the completion of the genome is a milestone, mobilizing this significant resource for better understanding the growth and development of woody perennials will be an even greater undertaking in the...

  13. Phytoremediation of landfill leachate using Populus

    Treesearch

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

    2006-01-01

    Proper genotype selection is required for successful phytoremediation. We selected eight Populus clones (NC13460, NC14018, DM115, NC14104, NC14106, DN5, NM2, NM6) of four genomic groups after three cycles of phyto-recurrent selection for a field trial that began June 2005 at the Oneida County Landfill in Rhinelander, WI, USA.

  14. Lignification of Sheepgrass Internodes at Different Developmental Stages and Associated Alteration of Cell Wall Saccharification Efficiency

    PubMed Central

    Wang, Jianli; Ma, Lichao; Shen, Zhongbao; Sun, Dequan; Zhong, Peng; Bai, Zetao; Zhang, Hailing; Cao, Yingping; Bao, Yan; Fu, Chunxiang

    2017-01-01

    Sheepgrass (Leymus chinensis) is a high-quality cool-season forage crop used as pasture and hay for livestock feeds. The presence of lignin in cell walls, however, impairs forage digestibility of such lignocellulosic feedstock. Here, the structural characterization and cell wall composition of sheepgrass internodes were studied, and a progressive increase in cell wall lignification was observed with internode maturation. Lignin composition analysis further revealed a gradual accumulation of guaiacyl and syringyl lignin units during internode development. Consistently, the transcript abundance of lignin-related genes was upregulated in mature internodes, suggesting their potential roles in lignin biosynthesis. Furthermore, the effects of cell wall composition and lignification extent on biomass saccharification efficiency were examined in sheepgrass. The results showed that lignin content, guaiacyl and syringyl lignin unit levels inversely correlated with cell wall digestibility, indicating that lignin is a crucial obstacle for utilizing sheepgrass feedstock. The baseline information obtained in this work will facilitate establishment, grazing management, harvesting and feedstock utilization of sheepgrass in future. PMID:28396679

  15. A mutation in the rice chalcone isomerase gene causes the golden hull and internode 1 phenotype.

    PubMed

    Hong, Lilan; Qian, Qian; Tang, Ding; Wang, Kejian; Li, Ming; Cheng, Zhukuan

    2012-07-01

    The biosynthesis of flavonoids, important secondary plant metabolites, has been investigated extensively, but few mutants of genes in this pathway have been identified in rice (Oryza sativa). The rice gold hull and internode (gh) mutants exhibit a reddish-brown pigmentation in the hull and internode and their phenotype has long been used as a morphological marker trait for breeding and genetic study. Here, we characterized that the gh1 mutant was a mutant of the rice chalcone isomerase gene (OsCHI). The result showed that gh1 had a Dasheng retrotransposon inserted in the 5′ UTR of the OsCHI gene, which resulted in the complete loss of OsCHI expression. gh1 exhibited golden pigmentation in hulls and internodes once the panicles were exposed to light. The total flavonoid content in gh1 hulls was increased threefold compared to wild type. Consistent with the gh1 phenotype, OsCHI transcripts were expressed in most tissues of rice and most abundantly in internodes. It was also expressed at high levels in panicles before heading, distributed mainly in lemmas and paleae, but its expression decreased substantially after the panicles emerged from the sheath. OsCHI encodes a protein functionally and structurally conserved to chalcone isomerases in other species. Our findings demonstrated that the OsCHI gene was indispensable for flux of the flavonoid pathway in rice.

  16. Node Detection and Internode Length Estimation of Tomato Seedlings Based on Image Analysis and Machine Learning

    PubMed Central

    Yamamoto, Kyosuke; Guo, Wei; Ninomiya, Seishi

    2016-01-01

    Seedling vigor in tomatoes determines the quality and growth of fruits and total plant productivity. It is well known that the salient effects of environmental stresses appear on the internode length; the length between adjoining main stem node (henceforth called node). In this study, we develop a method for internode length estimation using image processing technology. The proposed method consists of three steps: node detection, node order estimation, and internode length estimation. This method has two main advantages: (i) as it uses machine learning approaches for node detection, it does not require adjustment of threshold values even though seedlings are imaged under varying timings and lighting conditions with complex backgrounds; and (ii) as it uses affinity propagation for node order estimation, it can be applied to seedlings with different numbers of nodes without prior provision of the node number as a parameter. Our node detection results show that the proposed method can detect 72% of the 358 nodes in time-series imaging of three seedlings (recall = 0.72, precision = 0.78). In particular, the application of a general object recognition approach, Bag of Visual Words (BoVWs), enabled the elimination of many false positives on leaves occurring in the image segmentation based on pixel color, significantly improving the precision. The internode length estimation results had a relative error of below 15.4%. These results demonstrate that our method has the ability to evaluate the vigor of tomato seedlings quickly and accurately. PMID:27399708

  17. Identification of nodes and internodes of chopped biomass stems by Image analysis

    USDA-ARS?s Scientific Manuscript database

    Separating the morphological components of biomass leads to better handling, more efficient processing as well as value added product generation, as these components vary in their chemical composition and can be preferentially utilized. Nodes and internodes of biomass stems have distinct chemical co...

  18. Catalyst transport in corn stover internodes: elucidating transport mechanisms using Direct Blue-I.

    PubMed

    Viamajala, Sridhar; Selig, Michael J; Vinzant, Todd B; Tucker, Melvin P; Himmel, Michael E; McMillan, James D; Decker, Stephen R

    2006-01-01

    The transport of catalysts (chemicals and enzymes) within plant biomass is believed to be a major bottleneck during thermochemical pretreatment and enzymatic conversion of lignocellulose. Subjecting biomass to size reduction and mechanical homogenization can reduce catalyst transport limitations; however, such processing adds complexity and cost to the overall process. Using high-resolution light microscopy, we have monitored the transport of an aqueous solution of Direct Blue-I (DB-I) dye through intact corn internodes under a variety of impregnation conditions. DB-I is a hydrophilic anionic dye with affinity for cellulose. This model system has enabled us to visualize likely barriers and mechanisms of catalyst transport in corn stems. Microscopic images were compared with calculated degrees of saturation (i.e., volume fraction of internode void space occupied by dye solution) to correlate impregnation strategies with dye distribution and transport mechanisms. Results show the waxy rind exterior and air trapped within individual cells to be the major barriers to dye transport, whereas the vascular bundles, apoplastic continuum (i.e., the intercellular void space at cell junctions), and fissures formed during the drying process provided the most utilized pathways for transport. Although representing only 20-30% of the internode volume, complete saturation of the apoplast and vascular bundles by fluid allowed dye contact with a majority of the cells in the internode interior.

  19. Relationship of acid invertase activities to sugar content in sugarcane internodes during ripening and after harvest

    USDA-ARS?s Scientific Manuscript database

    It has been hypothesized that soluble acid invertase (SAI) and insoluble (cell wall) acid invertase (CWI) influence sucrose accumulation in sugarcane during ripening, and also postharvest deterioration. The activities of SAI and CWI were determined in selected immature and mature internodes during r...

  20. In vitro plant regeneration from leaves and internode sections of sweet cherry cultivars (Prunus avium L.).

    PubMed

    Matt, Andrea; Jehle, Johannes A

    2005-10-01

    Regeneration of adventitious shoots from leaves and, for the first time, from internode sections were compared and optimized for five economically important sweet cherry cultivars, i.e. "Schneiders", "Sweetheart", "Starking Hardy Giant", "Kordia" and "Regina" (Prunus avium L.). The influence of basal media, carbon source, combination and dosage of phytohormones, ethylene inhibitor such as silver thiosulfate and a 16 h:8 h light:dark photoperiod versus complete darkness were evaluated. Both, DKW/WPM (1:1) and Quoirin/Lepoivre (QL) basal media stimulated organogenesis more than QL/WPM (1:1), Chee and Pool (CP), Murashige Skoog (MS), Driver and Kuniyuki (DKW) or woody plant (WPM) media did. An induction phase in darkness resulted in lower or zero regeneration rates. The best regeneration efficiencies were generally obtained with thidiazuron in combination with indole-3-butyric-acid. The addition of silver thiosulfate resulted in a similar or reduced regeneration efficiency. Significant genotypic variability in adventitious bud formation was evident for both explant sources, leaf and internode section. Adventitious shoots were obtained from 11% of leaf explants and 50% of internode sections indicating that shoot regeneration from internodes was significantly more efficient than from leaves.

  1. Terra Populus and DataNet Collaboration

    NASA Astrophysics Data System (ADS)

    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

  2. Barcoding poplars (Populus L.) from western China.

    PubMed

    Feng, Jianju; Jiang, Dechun; Shang, Huiying; Dong, Miao; Wang, Gaini; He, Xinyu; Zhao, Changming; Mao, Kangshan

    2013-01-01

    Populus is an ecologically and economically important genus of trees, but distinguishing between wild species is relatively difficult due to extensive interspecific hybridization and introgression, and the high level of intraspecific morphological variation. The DNA barcoding approach is a potential solution to this problem. Here, we tested the discrimination power of five chloroplast barcodes and one nuclear barcode (ITS) among 95 trees that represent 21 Populus species from western China. Among all single barcode candidates, the discrimination power is highest for the nuclear ITS, progressively lower for chloroplast barcodes matK (M), trnG-psbK (G) and psbK-psbI (P), and trnH-psbA (H) and rbcL (R); the discrimination efficiency of the nuclear ITS (I) is also higher than any two-, three-, or even the five-locus combination of chloroplast barcodes. Among the five combinations of a single chloroplast barcode plus the nuclear ITS, H+I and P+I differentiated the highest and lowest portion of species, respectively. The highest discrimination rate for the barcodes or barcode combinations examined here is 55.0% (H+I), and usually discrimination failures occurred among species from sympatric or parapatric areas. In this case study, we showed that when discriminating Populus species from western China, the nuclear ITS region represents a more promising barcode than any maternally inherited chloroplast region or combination of chloroplast regions. Meanwhile, combining the ITS region with chloroplast regions may improve the barcoding success rate and assist in detecting recent interspecific hybridizations. Failure to discriminate among several groups of Populus species from sympatric or parapatric areas may have been the result of incomplete lineage sorting, frequent interspecific hybridizations and introgressions. We agree with a previous proposal for constructing a tiered barcoding system in plants, especially for taxonomic groups that have complex evolutionary histories

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

    PubMed

    Schilling, Martin P; Wolf, Paul G; Duffy, Aaron M; Rai, Hardeep S; Rowe, Carol A; Richardson, Bryce A; Mock, Karen E

    2014-01-01

    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.

  4. Morpho-anatomical traits of two lowest internodes related to lodging resistance in selected genotypes of Triticum

    NASA Astrophysics Data System (ADS)

    Packa, Danuta; Wiwart, Marian; Suchowilska, Elżbieta; Bieńkowska, Teresa

    2015-10-01

    The cross-sections of first and second internodes were analyzed under a light and fluorescence microscopes in six varieties of Triticum spelta, two varieties of T. polonicum, and one variety of T. aestivum. The morphometric parameters of stem cross-sections were measured. The analyzed wheats were characterized by significant differences in traits associated with lodging resistance ie: internode diameter, lumen diameter, stem wall thickness, mechanical layer thickness, area of transverse section, and area of lumen for the first and second internode and between the internodes. In all varieties, the values of internode diameter, lumen diameter, area of transverse section and area of lumen were higher for the second internode than for the first internode, whereas the reverse was reported for stem wall thickness and mechanical layer thickness The results of the principal component analysis and section modulus values revealed similarities between spring spelt Wirtas and Rubinas and between common wheat Kontesa and winter spelt Poeme and Epanis. The number of large vascular bundles varied across the studied varieties. The average number of vascular bundles in common wheat Kontesa was significantly higher than in spring spelt Rubinas and Wirtas and significantly lower than in Polish wheat Pol-3 and winter spelt Epanis and Poeme.

  5. Isolation of rice dwarf mutants with ectopic deposition of phenolic components including lignin in parenchyma cell walls of internodes.

    PubMed

    Sato, Kanna; Kawamura, Asuka; Obara, Tsukasa; Kawai, Shinya; Kajita, Shinya; Kitano, Hidemi; Katayama, Yoshihiro

    2011-12-01

    Rice internodes must have the proper shape to support high-yielding panicles. The shape of internodes is controlled by various factors involved in their formation, such as developmental patterns, cell division, cell elongation, and cell wall biosynthesis. To understand the regulation of internode development, we screened dwarf mutants to identify those with a phenotype of ectopic deposits of phenolic components in parenchyma cell walls of internodes. We named these mutants ectopic deposition of phenolic components1 (edp1). Two alleles were identified, edp1-1 and edp1-2. Furthermore, these mutants showed disordered cell files in internode parenchyma. These abnormal phenotypes were very similar to that of a previously reported dwarf50 (d50) mutant. Genetic analyses of edp1 mutants revealed that the edp1 loci are distinct from d50. Our results indicate that analyses of edp1 mutants as well as the d50 mutant will be useful for understanding the molecular mechanisms behind ectopic deposition of cell wall phenolic components in internode parenchyma cells and the regulation of internode development.

  6. Populus species from diverse habitats maintain high night-time conductance under drought.

    PubMed

    Cirelli, Damián; Equiza, María Alejandra; Lieffers, Victor James; Tyree, Melvin Thomas

    2016-02-01

    We investigated the interspecific variability in nocturnal whole-plant stomatal conductance under well-watered and drought conditions in seedlings of four species of Populus from habitats characterized by abundant water supply (mesic and riparian) or from drier upland sites. The study was carried out to determine whether (i) nocturnal conductance varies across different species of Populus according to their natural habitat, (ii) nocturnal conductance is affected by water stress similarly to daytime conductance based on species habitat and (iii) differences in conductance among species could be explained partly by differences in stomatal traits. We measured whole-plant transpiration and conductance (G) of greenhouse-grown seedlings using an automated high-resolution gravimetric technique. No relationship was found between habitat preference and daytime G (GD), but night-time G (GN) was on average 1.5 times higher in riparian and mesic species (P. deltoides Bartr. ex Marsh. and P. trichocarpa Torr. & Gray) than in those from drier environments (P. tremuloides Michx. and P. × petrowskyana Schr.). GN was not significantly reduced under drought in riparian species. Upland species restricted GN significantly in response to drought, but it was still at least one order of magnitude greater that the cuticular conductance until leaf death was imminent. Under both well-watered and drought conditions, GN declined with increasing vapour pressure deficit (D). Also, a small increase in GN towards the end of the night period was observed in P. deltoides and P. × petrowskyana, suggesting the involvement of endogenous regulation. The anatomical analyses indicated a positive correlation between G and variable stomatal pore index among species and revealed that stomata are not likely to be leaky but instead seem capable of complete occlusion, which raises the question of the possible physiological role of the significant GN observed under drought. Further comparisons among

  7. Rose bush leaf and internode expansion dynamics: analysis and development of a model capturing interplant variability

    PubMed Central

    Demotes-Mainard, Sabine; Bertheloot, Jessica; Boumaza, Rachid; Huché-Thélier, Lydie; Guéritaine, Gaëlle; Guérin, Vincent; Andrieu, Bruno

    2013-01-01

    Rose bush architecture, among other factors, such as plant health, determines plant visual quality. The commercial product is the individual plant and interplant variability may be high within a crop. Thus, both mean plant architecture and interplant variability should be studied. Expansion is an important feature of architecture, but it has been little studied at the level of individual organs in rose bushes. We investigated the expansion kinetics of primary shoot organs, to develop a model reproducing the organ expansion of real crops from non-destructive input variables. We took interplant variability in expansion kinetics and the model's ability to simulate this variability into account. Changes in leaflet and internode dimensions over thermal time were recorded for primary shoot expansion, on 83 plants from three crops grown in different climatic conditions and densities. An empirical model was developed, to reproduce organ expansion kinetics for individual plants of a real crop of rose bush primary shoots. Leaflet or internode length was simulated as a logistic function of thermal time. The model was evaluated by cross-validation. We found that differences in leaflet or internode expansion kinetics between phytomer positions and between plants at a given phytomer position were due mostly to large differences in time of organ expansion and expansion rate, rather than differences in expansion duration. Thus, in the model, the parameters linked to expansion duration were predicted by values common to all plants, whereas variability in final size and organ expansion time was captured by input data. The model accurately simulated leaflet and internode expansion for individual plants (RMSEP = 7.3 and 10.2% of final length, respectively). Thus, this study defines the measurements required to simulate expansion and provides the first model simulating organ expansion in rosebush to capture interplant variability. PMID:24167509

  8. Simplification of a light-based model for estimating final internode length in greenhouse cucumber canopies.

    PubMed

    Kahlen, Katrin; Stützel, Hartmut

    2011-10-01

    Light quantity and quality affect internode lengths in cucumber (Cucumis sativus), whereby leaf area and the optical properties of the leaves mainly control light quality within a cucumber plant community. This modelling study aimed at providing a simple, non-destructive method to predict final internode lengths (FILs) using light quantity and leaf area data. Several simplifications of a light quantity and quality sensitive model for estimating FILs in cucumber have been tested. The direct simplifications substitute the term for the red : far-red (R : FR) ratios, by a term for (a) the leaf area index (LAI, m(2) m(-2)) or (b) partial LAI, the cumulative leaf area per m(2) ground, where leaf area per m(2) ground is accumulated from the top of each plant until a number, n, of leaves per plant is reached. The indirect simplifications estimate the input R : FR ratio based on partial leaf area and plant density. In all models, simulated FILs were in line with the measured FILs over various canopy architectures and light conditions, but the prediction quality varied. The indirect simplification based on leaf area of ten leaves revealed the best fit with measured data. Its prediction quality was even higher than of the original model. This study showed that for vertically trained cucumber plants, leaf area data can substitute local light quality data for estimating FIL data. In unstressed canopies, leaf area over the upper ten ranks seems to represent the feedback of the growing architecture on internode elongation with respect to light quality. This highlights the role of this domain of leaves as the primary source for the specific R : FR signal controlling the final length of an internode and could therefore guide future research on up-scaling local processes to the crop level.

  9. Phosphatidylserine Synthase Controls Cell Elongation Especially in the Uppermost Internode in Rice by Regulation of Exocytosis.

    PubMed

    Ma, Jin; Cheng, Zhijun; Chen, Jun; Shen, Jinbo; Zhang, Baocai; Ren, Yulong; Ding, Yu; Zhou, Yihua; Zhang, Huan; Zhou, Kunneng; Wang, Jiu-Lin; Lei, Cailin; Zhang, Xin; Guo, Xiuping; Gao, He; Bao, Yiqun; Wan, Jian-Min

    2016-01-01

    The uppermost internode is one of the fastest elongating organs in rice, and is expected to require an adequate supply of cell-wall materials and enzymes to the cell surface to enhance mechanical strength. Although it has been reported that the phenotype of shortened uppermost internode 1 (sui1) is caused by mutations in PHOSPHATIDYLSERINE SYNTHASE (OsPSS), the underlying mechanism remains unclear. Here we show that the OsPSS-1, as a gene expressed predominantly in elongating cells, regulates post-Golgi vesicle secretion to intercellular spaces. Mutation of OsPSS-1 leads to compromised delivery of CESA4 and secGFP towards the cell surface, resulting in weakened intercellular adhesion and disorganized cell arrangement in parenchyma. The phenotype of sui1-4 is caused largely by the reduction in cellulose contents in the whole plant and detrimental delivery of pectins in the uppermost internode. We found that OsPSS-1 and its potential product PS (phosphatidylserine) localized to organelles associated with exocytosis. These results together suggest that OsPSS-1 plays a potential role in mediating cell expansion by regulating secretion of cell wall components.

  10. Phosphatidylserine Synthase Controls Cell Elongation Especially in the Uppermost Internode in Rice by Regulation of Exocytosis

    PubMed Central

    Chen, Jun; Shen, Jinbo; Zhang, Baocai; Ren, Yulong; Ding, Yu; Zhou, Yihua; Zhang, Huan; Zhou, Kunneng; Wang, Jiu-Lin; Lei, Cailin; Zhang, Xin; Guo, Xiuping; Gao, He; Bao, Yiqun; Wan, Jian-Min

    2016-01-01

    The uppermost internode is one of the fastest elongating organs in rice, and is expected to require an adequate supply of cell-wall materials and enzymes to the cell surface to enhance mechanical strength. Although it has been reported that the phenotype of shortened uppermost internode 1 (sui1) is caused by mutations in PHOSPHATIDYLSERINE SYNTHASE (OsPSS), the underlying mechanism remains unclear. Here we show that the OsPSS-1, as a gene expressed predominantly in elongating cells, regulates post-Golgi vesicle secretion to intercellular spaces. Mutation of OsPSS-1 leads to compromised delivery of CESA4 and secGFP towards the cell surface, resulting in weakened intercellular adhesion and disorganized cell arrangement in parenchyma. The phenotype of sui1-4 is caused largely by the reduction in cellulose contents in the whole plant and detrimental delivery of pectins in the uppermost internode. We found that OsPSS-1 and its potential product PS (phosphatidylserine) localized to organelles associated with exocytosis. These results together suggest that OsPSS-1 plays a potential role in mediating cell expansion by regulating secretion of cell wall components. PMID:27055010

  11. Brevis plant1, a putative inositol polyphosphate 5-phosphatase, is required for internode elongation in maize.

    PubMed

    Avila, Luis M; Cerrudo, Diego; Swanton, Clarence; Lukens, Lewis

    2016-03-01

    In maize (Zea mays L.), as in other grass species, stem elongation occurs during growth and most noticeably upon the transition to flowering. Genes that reduce stem elongation have been important to reduce stem breakage, or lodging. Stem elongation has been mediated by dwarf and brachytic/brevis plant mutants that affect giberellic acid and auxin pathways, respectively. Maize brevis plant1 (bv1) mutants, first identified over 80 years ago, strongly resemble brachytic2 mutants that have shortened internodes, short internode cells, and are deficient in auxin transport. Here, we characterized two novel bv1 maize mutants. We found that an inositol polyphosphate 5-phosphatase orthologue of the rice gene dwarf50 was the molecular basis for the bv1 phenotype, implicating auxin-mediated inositol polyphosphate and/or phosphoinositide signalling in stem elongation. We suggest that auxin-mediated internode elongation involves processes that also contribute to stem gravitropism. Genes misregulated in bv1 mutants included genes important for cell wall synthesis, transmembrane transport, and cytoskeletal function. Mutant and wild-type plants were indistinguishable early in development, responded similarly to changes in light quality, had unaltered flowering times, and had normal flower development. These attributes suggest that breeding could utilize bv1 alleles to increase crop grain yields.

  12. Brevis plant1, a putative inositol polyphosphate 5-phosphatase, is required for internode elongation in maize

    PubMed Central

    Avila, Luis M.; Cerrudo, Diego; Swanton, Clarence

    2016-01-01

    In maize (Zea mays L.), as in other grass species, stem elongation occurs during growth and most noticeably upon the transition to flowering. Genes that reduce stem elongation have been important to reduce stem breakage, or lodging. Stem elongation has been mediated by dwarf and brachytic/brevis plant mutants that affect giberellic acid and auxin pathways, respectively. Maize brevis plant1 (bv1) mutants, first identified over 80 years ago, strongly resemble brachytic2 mutants that have shortened internodes, short internode cells, and are deficient in auxin transport. Here, we characterized two novel bv1 maize mutants. We found that an inositol polyphosphate 5-phosphatase orthologue of the rice gene dwarf50 was the molecular basis for the bv1 phenotype, implicating auxin-mediated inositol polyphosphate and/or phosphoinositide signalling in stem elongation. We suggest that auxin-mediated internode elongation involves processes that also contribute to stem gravitropism. Genes misregulated in bv1 mutants included genes important for cell wall synthesis, transmembrane transport, and cytoskeletal function. Mutant and wild-type plants were indistinguishable early in development, responded similarly to changes in light quality, had unaltered flowering times, and had normal flower development. These attributes suggest that breeding could utilize bv1 alleles to increase crop grain yields. PMID:26767748

  13. Competence for Regeneration during Tobacco Internodal Development (Involvement of Plant Age, Cell Elongation Stage, and Degree of Polysomaty).

    PubMed Central

    Gilissen, LJW.; Van Staveren, M. J.; Hakkert, J. C.; Smulders, MJM.

    1996-01-01

    This study deals with internodal development in vegetative plants of Nicotiana tabacum cv Samsun NN and its reflection in changes of the cellular competence for regeneration. During elongation of the internodes, the cells of the epidermis, subepidermis, and cortex exclusively expanded and increased their DNA content cell type specifically, generally from 2C to 4C. Cells with the 8C DNA content were found mainly among the cortex cells of mature internodes. The frequency of shoot regeneration (directly from subepidermal and epidermal cells together) on thin cell layer explants increased to an optimum along with elongation of the internodes and decreased in mature internodes along with aging. The frequencies of diploid shoots among the regenerants from elongating and mature internodes were high (88 and 75% on the average, respectively), indicating that most cells that had achieved the 4C DNA content generally retained the G2 phase of the diploid cell cycle. Shoots regenerated from explants of young plant material mainly had a vitrified appearance. The occurrence of this type of malformed growth was already determined by the physiological state of the cells in the internode and did not interfere with their acquisition of competence. Vitrification was unrelated to the degree of polysomaty of the internodal tissue. Using the occurrence of tetraploid root regenerants (from intermediate cortex-derived callus), up to a frequency of 50%, we show that the position in the plant where a majority of the 4C cortex cells switched to the G1 phase of the tetraploid cell cycle was at the transition from the elongation phase to the mature phase. PMID:12226359

  14. Investigating the molecular genetic basis of heterosis for internode expansion in maize by microRNA transcriptomic deep sequencing.

    PubMed

    Zhao, Peng; Ding, Dong; Zhang, Fangfang; Zhao, Xiaofeng; Xue, Yadong; Li, Weihua; Fu, Zhiyuan; Li, Haochuan; Tang, Jihua

    2015-05-01

    Heterosis has been used widely in the breeding of maize and other crops and plays an important role in increasing yield, improving quality, and enhancing stress resistance, but its molecular mechanism is far from clear. To determine whether microRNA (miRNA)-dependent gene regulation is responsible for heterosis of elongating internodes below the ear and ear height in maize, a deep-sequencing strategy was applied to the elite hybrid Xundan20, which is currently cultivated widely in China, and its two parents. RNA was extracted from the eighth internode because it shows clear internode length heterosis. A total of 99 conserved maize miRNAs were detected in both the hybrid and parental lines. Most of these miRNAs were expressed nonadditively in the hybrid compared with its parental lines. These results indicated that miRNAs might participate in heterosis during internode expansion in maize and exert an influence on ear and plant height via the repression of their target genes. In total, eight novel miRNAs belonging to four miRNA families were predicted in the expanding internode. Global repression of miRNAs in the hybrid, which might result in enhanced gene expression, might be one reason why the hybrid shows longer internodes and taller seedlings compared with its parental lines.

  15. Survival and growth of 31 Populus clones in South Carolina

    Treesearch

    David R. Coyle; Mark D. Coleman; Jaclin A. Durant; Lee A. Newman

    2006-01-01

    Populus species and hybrids have many practical applications, but clonal performance is relatively undocumented in the southeastern United States outside of the Mississippi River alluvial floodplain. In spring 2001, 31 Populus clones were planted on two sites in South Carolina, USA. The sandy, upland site received irrigation and...

  16. Some implications of populus intensive culture on nongame birds

    Treesearch

    Richard L. Verch

    1983-01-01

    Intensive culture of Populus will affect nongame bird habitat. Conversion of old fields to Populus plantations will destroy habitat favorable to certain species and produce habitat that will attract different species. Effects of this conversion can be lessened by planting plantations with irregular shapes and by leaving patches (.4 hectares) of...

  17. Growth and biomass of Populus irrigated with landfill leachate

    Treesearch

    Jill A. Zalesny; Ronald S., Jr. Zalesny; David R. Coyle; Richard B. Hall

    2007-01-01

    Resource managers are challenged with waste disposal and leachate produced from its degradation. Poplar (Populus spp.) trees offer an opportunity for ecological leachate disposal as an irrigation source for managed tree systems. Our objective was to irrigate Populus trees with municipal solid waste landfill leachate or fertilized well water (control...

  18. Community type classification of forest vegetation in young, mixed stands, interior Alaska.

    Treesearch

    Andrew. Youngblood

    1993-01-01

    A total of 53 upland mixed communities were sampled and classified into five community types: Populus tremuloides/Arctostaphylos uva-ursi, Populus tremuloides/Shepherdla canadensis, Betula papyrifera-Populus tremuloides/Viburnum edule, Betula papyrifera-Populus tremuloldes/Alnus crispa and Picea glauca-Betula papyrlfera/Hylocomlum splendens. Community types were...

  19. Electrophysiological Mapping of Embryonic Mouse Hearts: Mechanisms for Developmental Pacemaker Switch and Internodal Conduction Pathway

    PubMed Central

    Yi, Tongyin; Wong, Johnson; Feller, Eric; Sink, Samantha; Taghli-lamallem, Ouarda; Wen, Jianyan; Kim, Changsung; Fink, Martin; Giles, Wayne; Soussou, Walid; Vincent Chen, Huei-Sheng

    2013-01-01

    Introduction Understanding sinoatrial node (SAN) development could help in developing therapies for SAN dysfunction. However, electrophysiological investigation of SAN development remains difficult because mutant mice with SAN dysfunctions are frequently embryonically lethal. Most research on SAN development is therefore limited to immunocytochemical observations without comparable functional studies. Methods and Results We applied a multi-electrode array (MEA) recording system to study SAN development in mouse hearts acutely isolated at embryonic ages (E) 8.5 to 12.5 days. Physiological heart rates were routinely restored, enabling accurate functional assessment of SAN development. We found that dominant pacemaking activity originated from the left inflow tract (LIFT) region at E8.5, but switched to the right SAN by E12.5. Combining MEA recordings and pharmacological agents, we show that intracellular calcium (Ca2+)-mediated automaticity develops early and is the major mechanism of pulse generation in the LIFT of E8.5 hearts. Later in development at E12.5, sarcolemmal ion channels develop in the SAN at a time when pacemaker channels are down regulated in the LIFT, leading to a switch in the dominant pacemaker location. Additionally, low micromolar concentrations of tetrodotoxin (TTX), a sodium channel blocker, minimally affect pacemaker rhythm at E8.5–12.5; but suppress atrial activation and reveal a tetrodotoxin-resistant SAN-atrioventricular node (internodal) pathway that mediates internodal conduction in E12.5 hearts. Conclusions Using a physiological mapping method, we demonstrate that differential mechanistic development of automaticity between the left and right inflow tract regions confers the pacemaker location switch. Moreover, a tetrodotoxin-resistant pathway mediates preferential internodal conduction in E12.5 mouse hearts. PMID:21985309

  20. Shaping the shoot: the relative contribution of cell number and cell shape to variations in internode length between parent and hybrid apple trees.

    PubMed

    Ripetti, V; Escoute, J; Verdeil, J L; Costes, E

    2008-01-01

    Genetic control of plant size and shape is a promising perspective, particularly in fruit trees, in order to select desirable genotypes. A recent study on architectural traits in an apple progeny showed that internode length was a highly heritable character. However, few studies have been devoted to internode cellular patterning in dicotyledonous stems, and the interplay between the two elementary cell processes that contribute to their length, i.e. cell division and elongation, is not fully understood. The present study aimed at unravelling their contributions in the genetic variation of internode length in a selection of F(1) and parent genotypes of apple tree, by exploring the number of cells and cell shape within mature internodes belonging to the main axes. The results highlighted that both the variables were homogeneous in samples collected either along a sagital line or along the pith width, and suggest that cell lengthening was homogeneous during internode development. They allowed the total number of cells to be estimated on the internode scale and opened up new perspectives for simplifying tissue sampling procedures for further investigations. Differences in internode length were observed between the genotypes, in particular between the parents, and partly resulted from a compensation between cell number and cell length. However, genetic variations in internode length primarily involved the number of cells, while cell length was more secondary. These results argue for an interplay between cellular and organismal control of internode shape that may involve the rib meristem.

  1. Characteristics in Sliding Motions of Small Organelles in a Nitella Internodal Cell

    NASA Astrophysics Data System (ADS)

    Uchida, Go; Nemoto, Tomomi; Tsuchiya, Yoshimi

    1995-12-01

    Steady velocities of small organelles smoothly moving on chloroplasts in a Nitella internodal cell have been investigated at various temperatures. It has been found that variance in the velocities of the organelles changes in proportion to their average velocity, which has been first elucidated from the temperature dependence of the organelle's velocity. This result suggests that the generation process of the force due to the actin-myosin is a Poisson like stochastic one. Thus, we have discussed a stochastic model for the motion of the organelle with many myosin-like molecules and estimated the force to be 4.2×10-12 N.

  2. Newly identified helper bacteria stimulate ectomycorrhizal formation in Populus

    SciTech Connect

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

    2014-10-24

    Mycorrhiza helper bacteria (MHB) are known to increase host root colonization by mycorrhizal fungi but the molecular mechanisms and potential tripartite trophic 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 other Pseudomonas strains (i.e., Pf-5 and BBc6R8) from existing collections were also included as reference in the screening process. We analyzed Laccaria bicolor S238N growth rate, mycelial architecture and transcriptional changes induced by the contrasting Pseudomonas strains (i.e., inhibitory, neutral and beneficial). We characterized 17 out of the 21 Pseudomonas strains from the Populus rhizosphere with positive effects on L. bicolor S238N growth, as well as on Populus root architecture and colonization by L. bicolor S238N across three Populus species. Four of seven reporter genes, Tra1, Tectonin2, Gcn5 and Cipc1, thought to be specific to the interaction with strain BBc6R8, were induced or repressed while interacting with six (i.e., GM17, GM33, GM41, GM48, Pf-5 and BBc6R8) of the tested Pseudomonas strains. 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 roots colonization. This tripartite relationship could be exploited in nursery production for target Populus species/genotypes as a means of improving establishment and survival in marginal lands.

  3. Newly identified helper bacteria stimulate ectomycorrhizal formation in Populus

    DOE PAGES

    Labbe, Jessy L.; Weston, David J.; Dunkirk, Nora; ...

    2014-10-24

    Mycorrhiza helper bacteria (MHB) are known to increase host root colonization by mycorrhizal fungi but the molecular mechanisms and potential tripartite trophic 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 other Pseudomonas strains (i.e., Pf-5 and BBc6R8) from existing collections were also included as reference in the screening process. We analyzed Laccaria bicolor S238N growth rate, mycelial architecture and transcriptional changes induced by the contrasting Pseudomonas strains (i.e., inhibitory, neutral and beneficial).more » We characterized 17 out of the 21 Pseudomonas strains from the Populus rhizosphere with positive effects on L. bicolor S238N growth, as well as on Populus root architecture and colonization by L. bicolor S238N across three Populus species. Four of seven reporter genes, Tra1, Tectonin2, Gcn5 and Cipc1, thought to be specific to the interaction with strain BBc6R8, were induced or repressed while interacting with six (i.e., GM17, GM33, GM41, GM48, Pf-5 and BBc6R8) of the tested Pseudomonas strains. 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 roots colonization. This tripartite relationship could be exploited in nursery production for target Populus species/genotypes as a means of improving establishment and survival in marginal lands.« less

  4. Predicting Plant Performance Under Simultaneously Changing Environmental Conditions—The Interplay Between Temperature, Light, and Internode Growth

    PubMed Central

    Kahlen, Katrin; Chen, Tsu-Wei

    2015-01-01

    Plant performance is significantly influenced by prevailing light and temperature conditions during plant growth and development. For plants exposed to natural fluctuations in abiotic environmental conditions it is however laborious and cumbersome to experimentally assign any contribution of individual environmental factors to plant responses. This study aimed at analyzing the interplay between light, temperature and internode growth based on model approaches. We extended the light-sensitive virtual plant model L-Cucumber by implementing a common Arrhenius function for appearance rates, growth rates, and growth durations. For two greenhouse experiments, the temperature-sensitive model approach resulted in a precise prediction of cucumber mean internode lengths and number of internodes, as well as in accurately predicted patterns of individual internode lengths along the main stem. In addition, a system's analysis revealed that environmental data averaged over the experimental period were not necessarily related to internode performance. Finally, the need for a species-specific parameterization of the temperature response function and related aspects in modeling temperature effects on plant development and growth is discussed. PMID:26734036

  5. Anthocyanins of the anthers as chemotaxonomic markers in the genus Populus L.. Differentiation between Populus nigra, Populus alba and Populus tremula.

    PubMed

    Alcalde-Eon, Cristina; García-Estévez, Ignacio; Rivas-Gonzalo, Julián C; Rodríguez de la Cruz, David; Escribano-Bailón, María Teresa

    2016-08-01

    Three main species of Popululs L. (Salicaceae) have been reported to occur in the Iberian Peninsula: Populus nigra L., Populus alba L. and Populus tremula L. The degree of pilosity of the bracts of the male catkins is a key character for their differentiation. The anthers of these poplar species possess anthocyanins that provide them a red colouration. Since these poplars are wind-pollinated and, consequently, do not need to attract pollinators, anthocyanins in the anthers might be acting as photoprotectors, shielding pollen grains from excessive sunlight. In order to verify this hypothesis, the first objective of this study was to establish if there is any relationship between the degree of pilosity of the bracts (related to the physical shading of the pollen grains) and the levels and types of anthocyanins in the anthers of these three species. This study also aimed to check the usefulness of the anthocyanins of the anthers as chemotaxonomic markers, through the study of the differences in the anthocyanin composition between these poplar species. Anthocyanins were identified from the data supplied by HPLC-DAD-MS(n) analyses. Seventeen different compounds, including mono-, di- and triglycosides and anthocyanin-derived pigments (F-A(+) dimers) have been identified. Cyanidin 3-O-glucoside was the major compound in all the samples (>60% of the total content), which may be in accordance with the photoprotective role proposed for them. However, qualitative and quantitative differences were detected among samples. Cyanidin and delphinidin 3-O-sambubiosides have been detected only in the anthers of P. tremula as well as cyanidin 3-O-(2″-O-xyloxyl)rutinoside, making them valuable chemotaxonomic markers for this species. Hierarchical Cluster and Principal Components Analyses (HCA and PCA) carried out with the anthocyanin percent composition data have allowed a separation of the samples that is in accordance with the initial classification of the samples made from the

  6. Gibberellin (GA) biosynthesis in elongating internodes Zea mays (maize): The 3. beta. -hydroxylase

    SciTech Connect

    Spray, C.R.; Phinney, B.O. ); Gaskin, P.; MacMillan, J. )

    1989-04-01

    The early-13-hydroxylation pathway for GA biosynthesis in maize leads to GA{sub 1}, the main GA responsible for shoot elongation. Growth response data, double-labeled feeding studies and endogenous GA levels suggest that the dwarf-1 mutant blocks the step GA{sub 20}to GA{sub 1}. We are screening for a system from maize from which we can purify the 3{beta}-hydroxylase and study its physical and biological properties. We find that diced internodal tissues will metabolize ({sup 13}C, {sup 3}H)-GA{sub 20} to ({sup 13}C, {sup 3}H)-GA{sub 1} and ({sup 13}C, {sup 3}H)-GA{sub 29} with metabolism as high as 80%. A cell free system from this material will give 5% metabolism. In a typical experiment 1g of internodal tissue is frozen in liquid nitrogen and macerated in 0.1M Tris plus cofactors. The homogenate is centrifuged at 15000 x g for 30 min at 4{degrees}C and the supernatant used for metabolic studies.

  7. Endogenous GABA controls oligodendrocyte lineage cell number, myelination, and CNS internode length

    PubMed Central

    Clarke, Laura E.; Arancibia‐Carcamo, I. Lorena; Kougioumtzidou, Eleni; Matthey, Moritz; Káradóttir, Ragnhildur; Whiteley, Louise; Bergersen, Linda H.; Richardson, William D.; Attwell, David

    2016-01-01

    Adjusting the thickness and internodal length of the myelin sheath is a mechanism for tuning the conduction velocity of axons to match computational needs. Interactions between oligodendrocyte precursor cells (OPCs) and developing axons regulate the formation of myelin around axons. We now show, using organotypic cerebral cortex slices from mice expressing eGFP in Sox10‐positive oligodendrocytes, that endogenously released GABA, acting on GABAA receptors, greatly reduces the number of oligodendrocyte lineage cells. The decrease in oligodendrocyte number correlates with a reduction in the amount of myelination but also an increase in internode length, a parameter previously thought to be set by the axon diameter or to be a property intrinsic to oligodendrocytes. Importantly, while TTX block of neuronal activity had no effect on oligodendrocyte lineage cell number when applied alone, it was able to completely abolish the effect of blocking GABAA receptors, suggesting that control of myelination by endogenous GABA may require a permissive factor to be released from axons. In contrast, block of AMPA/KA receptors had no effect on oligodendrocyte lineage cell number or myelination. These results imply that, during development, GABA can act as a local environmental cue to control myelination and thus influence the conduction velocity of action potentials within the CNS. GLIA 2017;65:309–321 PMID:27796063

  8. The maize d2003, a novel allele of VP8, is required for maize internode elongation.

    PubMed

    Lv, Hongkun; Zheng, Jun; Wang, Tianyu; Fu, Junjie; Huai, Junling; Min, Haowei; Zhang, Xiang; Tian, Baohua; Shi, Yunsu; Wang, Guoying

    2014-02-01

    The d2003 is a natural dwarf mutant from maize inbred line K36 and has less than one-third of K36 plant height with severely shortened internodes. In this study, we reported the cloning of d2003 gene using positional cloning. The results showed that there was a single-base insertion in the coding region of Viviparous8 (VP8) in d2003 mutant, which resulted in a premature stop codon. Further genetic allelism tests confirmed that d2003 mutation is a novel allele of VP8. VP8 is mainly expressed in the stem apex, young leaves, and developing vascular tissues, and its expression levels in nodes are significantly higher than that in internodes at 12-leaf stage. Subcellular localization demonstrated that the VP8 protein is localized to the endoplasmic reticulum and the N-terminal 26 amino acids (aa) of VP8 protein are essential to its localization in ER. Further transgenic experiments showed that lack of the 26 aa leads to loss of VP8 function in Arabidopsis amp1 phenotype rescue. These results strongly suggested that the N-terminal 26 aa is critical for VP8 protein localization, and the correct protein localization of VP8 in ER is necessary for its function.

  9. Cell walls and the developmental anatomy of the Brachypodium distachyon stem internode.

    PubMed

    Matos, Dominick A; Whitney, Ian P; Harrington, Michael J; Hazen, Samuel P

    2013-01-01

    While many aspects of plant cell wall polymer structure are known, their spatial and temporal distribution within the stem are not well understood. Here, we studied vascular system and fiber development, which has implication for both biofuel feedstock conversion efficiency and crop yield. The subject of this study, Brachypodium distachyon, has emerged as a grass model for food and energy crop research. Here, we conducted our investigation using B. distachyon by applying various histological approaches and Fourier transform infrared spectroscopy to the stem internode from three key developmental stages. While vascular bundle size and number did not change over time, the size of the interfascicular region increased dramatically, as did cell wall thickness. We also describe internal stem internode anatomy and demonstrate that lignin deposition continues after crystalline cellulose and xylan accumulation ceases. The vascular bundle anatomy of B. distachyon appears to be highly similar to domesticated grasses. While the arrangement of bundles within the stem is highly variable across grasses, B. distachyon appears to be a suitable model for the rind of large C4 grass crops. A better understanding of growth and various anatomical and cell wall features of B. distachyon will further our understanding of plant biomass accumulation processes.

  10. Endogenous GABA controls oligodendrocyte lineage cell number, myelination, and CNS internode length.

    PubMed

    Hamilton, Nicola B; Clarke, Laura E; Arancibia-Carcamo, I Lorena; Kougioumtzidou, Eleni; Matthey, Moritz; Káradóttir, Ragnhildur; Whiteley, Louise; Bergersen, Linda H; Richardson, William D; Attwell, David

    2017-02-01

    Adjusting the thickness and internodal length of the myelin sheath is a mechanism for tuning the conduction velocity of axons to match computational needs. Interactions between oligodendrocyte precursor cells (OPCs) and developing axons regulate the formation of myelin around axons. We now show, using organotypic cerebral cortex slices from mice expressing eGFP in Sox10-positive oligodendrocytes, that endogenously released GABA, acting on GABAA receptors, greatly reduces the number of oligodendrocyte lineage cells. The decrease in oligodendrocyte number correlates with a reduction in the amount of myelination but also an increase in internode length, a parameter previously thought to be set by the axon diameter or to be a property intrinsic to oligodendrocytes. Importantly, while TTX block of neuronal activity had no effect on oligodendrocyte lineage cell number when applied alone, it was able to completely abolish the effect of blocking GABAA receptors, suggesting that control of myelination by endogenous GABA may require a permissive factor to be released from axons. In contrast, block of AMPA/KA receptors had no effect on oligodendrocyte lineage cell number or myelination. These results imply that, during development, GABA can act as a local environmental cue to control myelination and thus influence the conduction velocity of action potentials within the CNS. GLIA 2017;65:309-321.

  11. Genome-Wide Identification of miRNAs and Their Targets Involved in the Developing Internodes under Maize Ears by Responding to Hormone Signaling.

    PubMed

    Zhao, Zhan; Xue, Yadong; Yang, Huili; Li, Huimin; Sun, Gaoyang; Zhao, Xiaofeng; Ding, Dong; Tang, Jihua

    2016-01-01

    Internode length is one of the decisive factors affecting plant height (PH) and ear height (EH), which are closely associated with the lodging resistance, biomass and grain yield of maize. miRNAs, currently recognized as important transcriptional/ post-transcriptional regulators, play an essential role in plant growth and development. However, their roles in developing internodes under maize ears remain unclear. To identify the roles of miRNAs and their targets in the development of internodes under maize ears, six miRNA and two degradome libraries were constructed using the 7th, 8th and 9th internodes of two inbred lines, 'Xun928' and 'Xun9058', which had significantly different internode lengths. A total of 45 and 54 miRNAs showed significant changes for each pairwise comparison among the 7th, 8th and 9th internodes of 'Xun9058' and 'Xun928', respectively. The expression of 31 miRNAs showed significant changes were common to the corresponding comparison groups of the 7th, 8th and 9th internodes of 'Xun9058' and 'Xun928'. For the corresponding internodes of 'Xun9058' and 'Xun928', compared with the expression of miRNAs in the 7th, 8th and 9th internodes of 'Xun928', the numbers of up-regulated and down-regulated miRNAs were 11 and 36 in the 7th internode, 9 and 45 in the 8th internode, and 9 and 25 in the 9th internode of 'Xun9058', respectively. Moreover, 10 miRNA families containing 45 members showed significant changes at least in two internodes of 'Xun928' by comparing with the corresponding internodes of 'Xun9058'. Based on the sequencing data, 20 miRNAs related to hormone signaling among the candidates, belonging to five conserved miRNA families, were selected for expression profiling using quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The five miRNA families, zma-miR160, zma-miR167, zma-miR164, zma-miR169 and zma-miR393, targeted the genes encoding auxin response factor, N-acetylcysteine domain containing protein, nuclear

  12. Plasticity of Sorghum Stem Biomass Accumulation in Response to Water Deficit: A Multiscale Analysis from Internode Tissue to Plant Level.

    PubMed

    Perrier, Lisa; Rouan, Lauriane; Jaffuel, Sylvie; Clément-Vidal, Anne; Roques, Sandrine; Soutiras, Armelle; Baptiste, Christelle; Bastianelli, Denis; Fabre, Denis; Dubois, Cécile; Pot, David; Luquet, Delphine

    2017-01-01

    Sorghum is increasingly used as a biomass crop worldwide. Its genetic diversity provides a large range of stem biochemical composition suitable for various end-uses as bioenergy or forage. Its drought tolerance enables it to reasonably sustain biomass production under water limited conditions. However, drought effect on the accumulation of sorghum stem biomass remains poorly understood which limits progress in crop improvement and management. This study aimed at identifying the morphological, biochemical and histological traits underlying biomass accumulation in the sorghum stem and its plasticity in response to water deficit. Two hybrids (G1, G4) different in stem biochemical composition (G4, more lignified, less sweet) were evaluated during 2 years in the field in Southern France, under two water treatments differentiated during stem elongation (irrigated; 1 month dry-down until an average soil water deficit of -8.85 bars). Plant phenology was observed weekly. At the end of the water treatment and at final harvest, plant height, stem and leaf dry-weight and the size, biochemical composition and tissue histology of internodes at 2-4 positions along the stem were measured. Stem biomass accumulation was significantly reduced by drought (in average 42% at the end of the dry-down). This was due to the reduction of the length, but not diameter, of the internodes expanded during water deficit. These internodes had more soluble sugar but lower lignin and cellulose contents. This was associated with a decrease of the areal proportion of lignified cell wall in internode outer zone whereas the areal proportion of this zone was not affected. All internodes for a given genotype and environment followed a common histochemical dynamics. Hemicellulose content and the areal proportion of inner vs. outer internode tissues were set up early during internode growth and were not drought responsive. G4 exhibited a higher drought sensitivity than G1 for plant height only. At final

  13. Genetic Dissection of Internode Length Above the Uppermost Ear in Four RIL Populations of Maize (Zea mays L.)

    PubMed Central

    Ku, Lixia; Cao, Liru; Wei, Xiaomin; Su, Huihui; Tian, Zhiqiang; Guo, Shulei; Zhang, Liangkun; Ren, Zhenzhen; Wang, Xiaobo; Zhu, Yuguang; Li, Guohui; Wang, Zhiyong; Chen, Yanhui

    2014-01-01

    The internode length above the uppermost ear (ILAU) is an important influencing factor for canopy architecture in maize. Analyzing the genetic characteristics of internode length is critical for improving plant population structure and increasing photosynthetic efficiency. However, the genetic control of ILAU has not been determined. In this study, quantitative trait loci (QTL) for internode length at five positions above the uppermost ear were identified using four sets of recombinant inbred line (RIL) populations in three environments. Genetic maps and initial QTL were integrated using meta-analyses across the four populations. Seventy QTL were identified: 16 in population 1; 14 in population 2; 25 in population 3; and 15 in population 4. Individual effects ranged from 5.36% to 26.85% of phenotypic variation, with 27 QTL >10%. In addition, the following common QTL were identified across two populations: one common QTL for the internode length of all five positions; one common QTL for the internode length of three positions; and one common QTL for the internode length of one position. In addition, four common QTL for the internode length of four positions were identified in one population. The results indicated that the ILAU at different positions above the uppermost ear could be affected by one or several of the same QTL. The traits may also be regulated by many different QTL. Of the 70 initial QTL, 46 were integrated in 14 meta-QTL (mQTLs) by meta-analysis, and 17 of the 27 initial QTL with R2 >10% were integrated in 7 mQTLs. Four of the key mQTLs (mQTL2-2, mQTL3-2, mQTL5-1, mQTL5-2, and mQTL9) in which the initial QTL displayed R2 >10% included four to 11 initial QTL for an internode length of four to five positions from one or two populations. These results may provide useful information for marker-assisted selection to improve canopy architecture. PMID:25538101

  14. A Populus EST resource for plant functional genomics

    PubMed Central

    Sterky, Fredrik; Bhalerao, Rupali R.; Unneberg, Per; Segerman, Bo; Nilsson, Peter; Brunner, Amy M.; Charbonnel-Campaa, Laurence; Lindvall, Jenny Jonsson; Tandre, Karolina; Strauss, Steven H.; Sundberg, Björn; Gustafsson, Petter; Uhlén, Mathias; Bhalerao, Rishikesh P.; Nilsson, Ove; Sandberg, Göran; Karlsson, Jan; Lundeberg, Joakim; Jansson, Stefan

    2004-01-01

    Trees present a life form of paramount importance for terrestrial ecosystems and human societies because of their ecological structure and physiological function and provision of energy and industrial materials. The genus Populus is the internationally accepted model for molecular tree biology. We have analyzed 102,019 Populus ESTs that clustered into 11,885 clusters and 12,759 singletons. We also provide >4,000 assembled full clone sequences to serve as a basis for the upcoming annotation of the Populus genome sequence. A public web-based EST database (populusdb) provides digital expression profiles for 18 tissues that comprise the majority of differentiated organs. The coding content of Populus and Arabidopsis genomes shows very high similarity, indicating that differences between these annual and perennial angiosperm life forms result primarily from differences in gene regulation. The high similarity between Populus and Arabidopsis will allow studies of Populus to directly benefit from the detailed functional genomic information generated for Arabidopsis, enabling detailed insights into tree development and adaptation. These data will also valuable for functional genomic efforts in Arabidopsis. PMID:15353603

  15. Immunolocalization of endogenous indole-3-acetic acid and abscisic acid in the shoot internodes of Fargesia yunnanensis bamboo during development

    Treesearch

    Shuguang Wang; Yongpeng Ma; Chengbin Wan; Chungyun Hse; Todd F. Shupe; Yujun Wang; Changming. Wang

    2016-01-01

    The Bambusoideae subfamily includes the fastest-growing plants worldwide, as a consequence of fast internode elongation. However, few studies have evaluated the temporal and spatial distribution of endogenous hormones during internode elongation. In this paper, endogenous indole-3-acetic acid (IAA) and abscisic acid (ABA) were detected in different developmental...

  16. Expression of a fungal glucuronoyl esterase in Populus: effects on wood properties and saccharification efficiency.

    PubMed

    Latha Gandla, Madhavi; Derba-Maceluch, Marta; Liu, Xiaokun; Gerber, Lorenz; Master, Emma R; Mellerowicz, Ewa J; Jönsson, Leif J

    2015-04-01

    The secondary walls of angiosperms contain large amounts of glucuronoxylan that is thought to be covalently linked to lignin via ester bonds between 4-O-methyl-α-D-glucuronic acid (4-O-Me-GlcA) moieties in glucuronoxylan and alcohol groups in lignin. This linkage is proposed to be hydrolysed by glucuronoyl esterases (GCEs) secreted by wood-degrading fungi. We report effects of overexpression of a GCE from the white-rot basidiomycete Phanerochaete carnosa, PcGCE, in hybrid aspen (Populus tremula L. x tremuloides Michx.) on the wood composition and the saccharification efficiency. The recombinant enzyme, which was targeted to the plant cell wall using the signal peptide from hybrid aspen cellulase PttCel9B3, was constitutively expressed resulting in the appearance of GCE activity in protein extracts from developing wood. Diffuse reflectance FT-IR spectroscopy and pyrolysis-GC/MS analyses showed significant alternation in wood chemistry of transgenic plants including an increase in lignin content and S/G ratio, and a decrease in carbohydrate content. Sequential wood extractions confirmed a massive (+43%) increase of Klason lignin, which was accompanied by a ca. 5% decrease in cellulose, and ca. 20% decrease in wood extractives. Analysis of the monosaccharide composition using methanolysis showed a reduction of 4-O-Me-GlcA content without a change in Xyl contents in transgenic lines, suggesting that the covalent links between 4-O-Me-GlcA moieties and lignin protect these moieties from degradation. Enzymatic saccharification without pretreatment resulted in significant decreases of the yields of Gal, Glc, Xyl and Man in transgenic lines, consistent with their increased recalcitrance caused by the increased lignin content. In contrast, the enzymatic saccharification after acid pretreatment resulted in Glc yields similar to wild-type despite of their lower cellulose content. These data indicate that whereas PcGCE expression in hybrid aspen increases lignin deposition

  17. Kinetic analysis using low-molecular mass xyloglucan oligosaccharides defines the catalytic mechanism of a Populus xyloglucan endotransglycosylase

    PubMed Central

    Saura-Valls, Marc; Fauré, Régis; Ragàs, Sergi; Piens, Kathleen; Brumer, Harry; Teeri, Tuula T.; Cottaz, Sylvain; Driguez, Hugues; Planas, Antoni

    2005-01-01

    Plant XETs [XG (xyloglucan) endotransglycosylases] catalyse the transglycosylation from a XG donor to a XG or low-molecular-mass XG fragment as the acceptor, and are thought to be important enzymes in the formation and remodelling of the cellulose-XG three-dimensional network in the primary plant cell wall. Current methods to assay XET activity use the XG polysaccharide as the donor substrate, and present limitations for kinetic and mechanistic studies of XET action due to the polymeric and polydisperse nature of the substrate. A novel activity assay based on HPCE (high performance capillary electrophoresis), in conjunction with a defined low-molecular-mass XGO {XG oligosaccharide; (XXXGXXXG, where G=Glcβ1,4- and X=[Xylα1,6]Glcβ1,4-)} as the glycosyl donor and a heptasaccharide derivatized with ANTS [8-aminonaphthalene-1,3,6-trisulphonic acid; (XXXG-ANTS)] as the acceptor substrate was developed and validated. The recombinant enzyme PttXET16A from Populus tremula x tremuloides (hybrid aspen) was characterized using the donor/acceptor pair indicated above, for which preparative scale syntheses have been optimized. The low-molecular-mass donor underwent a single transglycosylation reaction to the acceptor substrate under initial-rate conditions, with a pH optimum at 5.0 and maximal activity between 30 and 40 °C. Kinetic data are best explained by a ping-pong bi-bi mechanism with substrate inhibition by both donor and acceptor. This is the first assay for XETs using a donor substrate other than polymeric XG, enabling quantitative kinetic analysis of different XGO donors for specificity, and subsite mapping studies of XET enzymes. PMID:16356166

  18. Structure and stability of internodal myelin in mouse models of hereditary neuropathy.

    PubMed

    Avila, Robin L; Inouye, Hideyo; Baek, Rena C; Yin, Xinghua; Trapp, Bruce D; Feltri, M Laura; Wrabetz, Lawrence; Kirschner, Daniel A

    2005-11-01

    Peripheral neuropathies often result in abnormalities in the structure of internodal myelin, including changes in period and membrane packing, as observed by electron microscopy (EM). Mutations in the gene that encodes the major adhesive structural protein of internodal myelin in the peripheral nervous system of humans and mice--P0 glycoprotein--correlate with these defects. The mechanisms by which P0 mutations interfere with myelin packing and stability are not well understood and cannot be provided by EM studies that give static and qualitative information on fixed material. To gain insights into the pathogenesis of mutant P0, we used x-ray diffraction, which can detect more subtle and dynamic changes in native myelin, to investigate myelin structure in sciatic nerves from murine models of hereditary neuropathies. We used mice with disruption of one or both copies of the P0 gene (models of Charcot-Marie-Tooth-like neuropathy [CMT1B] or Dejerine-Sottas-like neuropathy) and mice with a CMT1B resulting from a transgene encoding P0 with an amino terminal myc-tag. To directly test the structural role of P0, we also examined a mouse that expresses P0 instead of proteolipid protein in central nervous system myelin. To link our findings on unfixed nerves with EM results, we analyzed x-ray patterns from unembedded, aldehyde-fixed nerves and from plastic-embedded nerves. From the x-ray patterns recorded from whole nerves, we assessed the amount of myelin and its quality (i.e. relative thickness and regularity). Among sciatic nerves having different levels of P0, we found that unfixed nerves and, to a lesser extent, fixed but unembedded nerves gave diffraction patterns of sufficient quality to distinguish periods, sometimes differing by a few Angstroms. Certain packing abnormalities were preserved qualitatively by aldehyde fixation, and the relative amount and structural integrity of myelin among nerves could be distinguished. Measurements from the same nerve over time

  19. Is the basal area of maize internodes involved in borer resistance?

    PubMed Central

    2011-01-01

    Background To elucidate the role of the length of the internode basal ring (LIBR) in resistance to the Mediterranean corn borer (MCB), we carried out a divergent selection program to modify the LIBR using two maize synthetic varieties (EPS20 and EPS21), each with a different genetic background. We investigated the biochemical mechanisms underlying the relationship between the LIBR and borer resistance. Selection to lengthen or shorten the LIBR was achieved for each synthetic variety. The resulting plants were analyzed to determine their LIBR response, growth, yield, and borer resistance. Results In the synthetic variety EPS20 (Reid germplasm), reduction of the LIBR improved resistance against the MCB. The LIBR selection was also effective in the synthetic variety EPS21 (non-Reid germplasm), although there was no relationship detected between the LIBR and MCB resistance. The LIBR did not show correlations with agronomic traits such as plant height and yield. Compared with upper sections, the internode basal ring area contained lower concentrations of cell wall components such as acid detergent fiber (ADF), acid detergent lignin (ADL), and diferulates. In addition, some residual 2,4-dihydroxy-7-methoxy-(2H)-1,4-benzoxazin-3-(4H)-one (DIMBOA), a natural antibiotic compound, was detected in the basal area at 30 days after silking. Conclusion We analyzed maize selections to determine whether the basal area of maize internodes is involved in borer resistance. The structural reinforcement of the cell walls was the most significant trait in the relationship between the LIBR and borer resistance. Lower contents of ADF and ADL in the rind of the basal section facilitated the entry of larvae in this area in both synthetic varieties, while lower concentrations of diferulates in the pith basal section of EPS20 facilitated larval feeding inside the stem. The higher concentrations of DIMBOA may have contributed to the lack of correlation between the LIBR and borer resistance in

  20. Community type classification of forest vegetation in young, mixed stands, interior Alaska. Forest Service research paper

    SciTech Connect

    Youngblood, A.

    1993-04-01

    A total of 53 upland mixed communities were sampled and classified into five community types: Populus tremuloides/Arctostaphylos uva-ursi, Populus tremuloides/Shepherdia canadensis, Betula papyrifera-Populus tremuloides/Viburnum edule, Betula papyrifera-Populus tremuloides/Alnus crispa and Picea glauca-Betula papyrifera/ Hylocomlum splendens. Community types were described by distribution and physical environment, vegetation composition, structural features, and relation to previously described vegetation units.

  1. Validation of Bayesian kriging of arsenic, chromium, lead and mercury surface soil concentrations based on internode sampling

    PubMed Central

    Aelion, C.M.; Davis, H.T.; Liu, Y.; Lawson, A.B.; McDermott, S.

    2009-01-01

    Bayesian kriging is a useful tool for estimating spatial distributions of metals; however, estimates are generally only verified statistically. In this study surface soil samples were collected on a uniform grid and analyzed for As, Cr, Pb, and Hg. The data were interpolated at individual locations by Bayesian kriging. Estimates were validated using a leave-one-out cross validation (LOOCV) statistical method which compared the measured and LOOCV predicted values. Validation also was carried out using additional field sampling of soil metal concentrations at points between original sampling locations, which were compared to kriging prediction distributions. LOOCV results suggest that Bayesian kriging was a good predictor of metal concentrations. When measured internode metal concentrations and estimated kriged values were compared, the measured values were located within the 5th – 95th percentile prediction distributions in over half of the internode locations. Estimated and measured internode concentrations were most similar for As and Pb. Kriged estimates did not compare as well to measured values for concentrations below the analytical minimum detection limit, or for internode samples that were very close to the original sampling node. Despite inherent variability in metal concentrations in soils, the kriged estimates were validated statistically and by in situ measurement. PMID:19603658

  2. Validation of Bayesian kriging of arsenic, chromium, lead, and mercury surface soil concentrations based on internode sampling.

    PubMed

    Aelion, C M; Davis, H T; Liu, Y; Lawson, A B; McDermott, S

    2009-06-15

    Bayesian kriging is a useful tool for estimating spatial distributions of metals; however, estimates are generally only verified statistically. In this study surface soil samples were collected on a uniform grid and analyzed for As, Cr, Pb, and Hg. The data were interpolated at individual locations by Bayesian kriging. Estimates were validated using a leave-one-out cross validation (LOOCV) statistical method which compared the measured and LOOCV predicted values. Validation also was carried out using additional field sampling of soil metal concentrations at points between original sampling locations, which were compared to kriging prediction distributions. LOOCV results suggest that Bayesian kriging was a good predictor of metal concentrations. When measured internode metal concentrations and estimated kriged values were compared, the measured values were located within the 5th-95th percentile prediction distributions in over half of the internode locations. Estimated and measured internode concentrations were most similar for As and Pb. Kriged estimates did not compare as well to measured values for concentrations below the analytical minimum detection limit, or for internode samples that were very close to the original sampling node. Despite inherent variability in, metal concentrations in soils, the kriged estimates were validated statistically and by in situ measurement.

  3. Investigation of Inter-Node B Macro Diversity for Single-Carrier Based Radio Access in Evolved UTRA Uplink

    NASA Astrophysics Data System (ADS)

    Kawai, Hiroyuki; Morimoto, Akihito; Higuchi, Kenichi; Sawahashi, Mamoru

    This paper investigates the gain of inter-Node B macro diversity for a scheduled-based shared channel using single-carrier FDMA radio access in the Evolved UTRA (UMTS Terrestrial Radio Access) uplink based on system-level simulations. More specifically, we clarify the gain of inter-Node B soft handover (SHO) with selection combining at the radio frame length level (=10msec) compared to that for hard handover (HHO) for a scheduled-based shared data channel, considering the gains of key packet-specific techniques including channel-dependent scheduling, adaptive modulation and coding (AMC), hybrid automatic repeat request (ARQ) with packet combining, and slow transmission power control (TPC). Simulation results show that the inter-Node B SHO increases the user throughput at the cell edge by approximately 10% for a short cell radius such as 100-300m due to the diversity gain from a sudden change in other-cell interference, which is a feature specific to full scheduled-based packet access. However, it is also shown that the gain of inter-Node B SHO compared to that for HHO is small in a macrocell environment when the cell radius is longer than approximately 500m due to the gains from hybrid ARQ with packet combining, slow TPC, and proportional fairness based channel-dependent scheduling.

  4. Internode and petiole elongation of soybean in response to photoperiod and end-of-day light quality

    NASA Technical Reports Server (NTRS)

    Thomas, J. F.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

    1985-01-01

    Elongation of main stem internodes and petioles of soybeans, Glycine max 'Ransom,' was examined in response to various photoperiod/temperature combinations and to end-of-day (EOD) light quality. Photoperiod treatments consisted of 10, 14, and 16 h in combination with day/night temperatures of 18/14, 22/18, 26/22, 30/26, and 34/30 C. The EOD treatments consisted of exposing plants to illumination from either incandescent (high far-red component, FR) or fluorescent (high red component, R) lamps during the final 0.5 h of a 10-h photoperiod. Internode elongation was not significantly promoted by the photoperiod treatments, and, in fact, under the two highest temperature regimes, internode elongation was suppressed under the longer photoperiods. Petiole elongation, however, was enhanced under the longer photoperiods at all temperatures. In the EOD light study, internode and petiole elongation was significantly greater on plants exposed to 0.5 h EOD from incandescent lamps than from fluorescent. Under the incandescent EOD treatment, plants increased dry matter production by 41% and exhibited greater partitioning of assimilates in stem and root portions than under fluorescent EOD.

  5. Internode and petiole elongation of soybean in response to photoperiod and end-of-day light quality

    NASA Technical Reports Server (NTRS)

    Thomas, J. F.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

    1985-01-01

    Elongation of main stem internodes and petioles of soybeans, Glycine max 'Ransom,' was examined in response to various photoperiod/temperature combinations and to end-of-day (EOD) light quality. Photoperiod treatments consisted of 10, 14, and 16 h in combination with day/night temperatures of 18/14, 22/18, 26/22, 30/26, and 34/30 C. The EOD treatments consisted of exposing plants to illumination from either incandescent (high far-red component, FR) or fluorescent (high red component, R) lamps during the final 0.5 h of a 10-h photoperiod. Internode elongation was not significantly promoted by the photoperiod treatments, and, in fact, under the two highest temperature regimes, internode elongation was suppressed under the longer photoperiods. Petiole elongation, however, was enhanced under the longer photoperiods at all temperatures. In the EOD light study, internode and petiole elongation was significantly greater on plants exposed to 0.5 h EOD from incandescent lamps than from fluorescent. Under the incandescent EOD treatment, plants increased dry matter production by 41% and exhibited greater partitioning of assimilates in stem and root portions than under fluorescent EOD.

  6. The Aquatic Communities Inhabiting Internodes of Two Sympatric Bamboos in Argentinean Subtropical Forest

    PubMed Central

    Campos, Raúl E.

    2013-01-01

    In order to determine if phytotelmata in sympatric bamboos of the genus Guadua might be colonized by different types of arthropods and contain communities of different complexities, the following objectives were formulated: (1) to analyze the structure and species richness of the aquatic macroinvertebrate communities, (2) to comparatively analyze co-occurrences; and (3) to identify the main predators. Field studies were conducted in a subtropical forest in Argentina, where 80 water-filled bamboo internodes of Guadua chacoensis (Rojas Acosta) Londoño and Peterson (Poales: Poaceae) and G. trinii (Nees) Nees and Rupr. were sampled. Morphological measurements indicated that G. chacoensis held more fluid than G. trinii. The communities differed between Guadua species, but many macroinvertebrate species used both bamboo species. The phytotelmata were mainly colonized by Diptera of the families Culicidae and Ceratopogonidae. PMID:24224775

  7. Managing internode data communications for an uninitialized process in a parallel computer

    DOEpatents

    Archer, Charles J; Blocksome, Michael A; Miller, Douglas R; Parker, Jeffrey J; Ratterman, Joseph D; Smith, Brian E

    2014-05-20

    A parallel computer includes nodes, each having main memory and a messaging unit (MU). Each MU includes computer memory, which in turn includes, MU message buffers. Each MU message buffer is associated with an uninitialized process on the compute node. In the parallel computer, managing internode data communications for an uninitialized process includes: receiving, by an MU of a compute node, one or more data communications messages in an MU message buffer associated with an uninitialized process on the compute node; determining, by an application agent, that the MU message buffer associated with the uninitialized process is full prior to initialization of the uninitialized process; establishing, by the application agent, a temporary message buffer for the uninitialized process in main computer memory; and moving, by the application agent, data communications messages from the MU message buffer associated with the uninitialized process to the temporary message buffer in main computer memory.

  8. Conversion of the proprietary ROLM (tm) inter-node link from multimode to singlemode operation

    NASA Technical Reports Server (NTRS)

    Boucher, Larry

    1993-01-01

    Many NASA centers have selected ROLM(TM) Computerized Branch Exchanges (CBX's) as their standard telephone exchange. The ROLM 9751 CBX Model 70 with ROLM software release 9005 can inter-communicate as a 'multi-node' system over a multimode fiber optic link of 450 to 6,000 meters. Singlemode fiber installations are not supported by ROLM. Two New Mexico-based NASA satellite ground terminals were already connected via a 6 kilometer singlemode fiber optic link. The ROLM Inter-Node Link (INL) was converted from multimode LED transmitters to singlemode laser transmitters and two ROLM CBX systems were interconnected using the modified INL. On activation, the system operated normally and has done so for six months. System testing indicates sufficient margin to drive 45 kilometers of singlemode fiber, an important benefit for widely separated facilities.

  9. Elongating internodes of Zea mays (maize): Early steps in the GA biosynthetic pathway

    SciTech Connect

    Suzuki, Y.; Phinney, B.O. ); Gaskin, P.; MacMillan, J. )

    1989-04-01

    The early steps in the gibberellin (GA) biosynthetic pathway have yet to be defined for tissues that show a growth response to GAs. To this end we have synthesized the ({sup 13}C,{sup 3}H)-ent-kaurenoids, ent-kaurenol, ent-kaurenal ent-kaukenoic acid. We also have double-labeled ent-kaurene and double-labeled GA{sub 12}-aldehyde. We feed 1 - 10{mu}g of each substrate, individually, to 1.0g diced internodes in the appropriate buffer plus cofactors. We have observed up to 80% metabolism. We have identified (full scan GC-MS) 7{beta}-hydroxy-ent-kaurenoic acid as the major metabolite from double-labeled ent-kaurenoic acid feeds, thus defining the step ent-kaurenoic acid to 7{beta}-hydroxy-ent-kaurenoic acid.

  10. Osmotic properties of pea internodes in relation to growth and auxin action

    SciTech Connect

    Cosgrove, D.J.; Cleland, R.E.

    1983-01-01

    The water transport properties of etiolated pea (Pisum sativum L.) internodes were studied using both dynamic and steady-state methods to determine (a) whether water transport through the growing tissue limits the rate of cell enlargement, and (b) whether auxin stimulates growth in part by increasing the hydraulic conductance of the growing tissue. Measurements using the pressure probe technique showed that the hydraulic conductivity of cortical cell membranes was the same for both slowly growing and auxin-induced rapidly growing cells (membrane hydraulic conductivity, about 1.5 x 10/sup -5/ centimeters per second per bar). In a second technique which measured the rate of water movement through the entire pea internode, the half-time for radial water flow was about 60 seconds and was not altered by auxin application. These results indicate that auxin does not alter the hydraulic conductance of pea stem tissue, either at the cellular or the whole tissue level. When the growth rate was altered by various treatments, including decapitation, auxin application, cold temperature, and KCN treatment, the water potential was independent of the growth rate of the stem. We attribute the depression of the water potential in young pea stems to the presence of solutes in the cell wall free space of the tissue. From the results of these dynamic and steady-state experiments, we conclude that the internal gradient in water potential (from the xylem to the epidermis) needed to sustain cell enlargement is small (no greater than 0.5 bar). Thus, the hydraulic conductance of the tissue is sufficiently large that it does not control or limit the rate of cell enlargement. 30 references, 5 figures, 4 tables.

  11. Identification of Dw1, a Regulator of Sorghum Stem Internode Length

    PubMed Central

    Hilley, Josie; Truong, Sandra; Olson, Sara; Morishige, Daryl; Mullet, John

    2016-01-01

    Sorghum is an important C4 grain and grass crop used for food, feed, forage, sugar, and biofuels. In its native Africa, sorghum landraces often grow to approximately 3–4 meters in height. Following introduction into the U.S., shorter, early flowering varieties were identified and used for production of grain. Quinby and Karper identified allelic variation at four loci designated Dw1-Dw4 that regulated plant height by altering the length of stem internodes. The current study used a map-based cloning strategy to identify the gene corresponding to Dw1. Hegari (Dw1dw2Dw3dw4) and 80M (dw1dw2Dw3dw4) were crossed and F2 and HIF derived populations used for QTL mapping. Genetic analysis identified four QTL for internode length in this population, Dw1 on SBI-09, Dw2 on SBI-06, and QTL located on SBI-01 and SBI-07. The QTL on SBI-07 was ~3 Mbp upstream of Dw3 and interacted with Dw1. Dw1 was also found to contribute to the variation in stem weight in the population. Dw1 was fine mapped to an interval of ~33 kbp using HIFs segregating only for Dw1. A polymorphism in an exon of Sobic.009G229800 created a stop codon that truncated the encoded protein in 80M (dw1). This polymorphism was not present in Hegari (Dw1) and no other polymorphisms in the delimited Dw1 locus altered coding regions. The recessive dw1 allele found in 80M was traced to Dwarf Yellow Milo, the progenitor of grain sorghum genotypes identified as dw1. Dw1 encodes a putative membrane protein of unknown function that is highly conserved in plants. PMID:26963094

  12. The ERF11 Transcription Factor Promotes Internode Elongation by Activating Gibberellin Biosynthesis and Signaling1[OPEN

    PubMed Central

    Zhou, Xin; Zhang, Zhong-Lin; Tyler, Ludmila; Yusuke, Jikumaru; Qiu, Kai; Lumba, Shelley; Desveaux, Darrell; McCourt, Peter; Sun, Tai-ping

    2016-01-01

    The phytohormone gibberellin (GA) plays a key role in promoting stem elongation in plants. Previous studies show that GA activates its signaling pathway by inducing rapid degradation of DELLA proteins, GA signaling repressors. Using an activation-tagging screen in a reduced-GA mutant ga1-6 background, we identified AtERF11 to be a novel positive regulator of both GA biosynthesis and GA signaling for internode elongation. Overexpression of AtERF11 partially rescued the dwarf phenotype of ga1-6. AtERF11 is a member of the ERF (ETHYLENE RESPONSE FACTOR) subfamily VIII-B-1a of ERF/AP2 transcription factors in Arabidopsis (Arabidopsis thaliana). Overexpression of AtERF11 resulted in elevated bioactive GA levels by up-regulating expression of GA3ox1 and GA20ox genes. Hypocotyl elongation assays further showed that overexpression of AtERF11 conferred elevated GA response, whereas loss-of-function erf11 and erf11 erf4 mutants displayed reduced GA response. In addition, yeast two-hybrid, coimmunoprecipitation, and transient expression assays showed that AtERF11 enhances GA signaling by antagonizing the function of DELLA proteins via direct protein-protein interaction. Interestingly, AtERF11 overexpression also caused a reduction in the levels of another phytohormone ethylene in the growing stem, consistent with recent finding showing that AtERF11 represses transcription of ethylene biosynthesis ACS genes. The effect of AtERF11 on promoting GA biosynthesis gene expression is likely via its repressive function on ethylene biosynthesis. These results suggest that AtERF11 plays a dual role in promoting internode elongation by inhibiting ethylene biosynthesis and activating GA biosynthesis and signaling pathways. PMID:27255484

  13. Newly identified helper bacteria stimulate ectomycorrhizal formation in Populus

    PubMed Central

    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. PMID:25386184

  14. Revisiting the sequencing of the first tree genome: Populus trichocarpa.

    PubMed

    Wullschleger, Stan D; Weston, D J; DiFazio, S P; Tuskan, G A

    2013-04-01

    Ten years ago, it was announced that the Joint Genome Institute with funds provided by the Department of Energy, Office of Science, Biological and Environmental Research would sequence the black cottonwood (Populus trichocarpa Torr. & Gray) genome. This landmark decision was the culmination of work by the forest science community to develop Populus as a model system. Since its public release in late 2006, the availability of the Populus genome has spawned research in plant biology, morphology, genetics and ecology. Here we address how the tree physiologist has used this resource. More specifically, we revisit our earlier contention that the rewards of sequencing the Populus genome would depend on how quickly scientists working with woody perennials could adopt molecular approaches to investigate the mechanistic underpinnings of basic physiological processes. Several examples illustrate the integration of functional and comparative genomics into the forest sciences, especially in areas that target improved understanding of the developmental differences between woody perennials and herbaceous annuals (e.g., phase transitions). Sequencing the Populus genome and the availability of genetic and genomic resources has also been instrumental in identifying candidate genes that underlie physiological and morphological traits of interest. Genome-enabled research has advanced our understanding of how phenotype and genotype are related and provided insights into the genetic mechanisms whereby woody perennials adapt to environmental stress. In the future, we anticipate that low-cost, high-throughput sequencing will continue to facilitate research in tree physiology and enhance our understanding at scales of individual organisms and populations. A challenge remains, however, as to how genomic resources, including the Populus genome, can be used to understand ecosystem function. Although examples are limited, progress in this area is encouraging and will undoubtedly improve as

  15. Biomass and genotype × environment interactions of Populus energy crops in the midwestern United States

    Treesearch

    Ronald S., Jr. Zalesny; Richard B. Hall; Jill A. Zalesny; Bernard G. McMahon; William E. Berguson; Glen R. Stanosz

    2009-01-01

    Using Populus feedstocks for biofuels, bioenergy, and bioproducts is becoming economically feasible as global fossil fuel prices increase. Maximizing Populus biomass production across regional landscapes largely depends on understanding genotype × environment interactions, given broad genetic variation at strategic (...

  16. Effects of Cottonwood Leaf Beetle (Coleoptera: Chrysomelidae) Larval Defoliation, Clone, and Season on Populus Foliar Phagostimulants

    Treesearch

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

    2003-01-01

    Abstract: The cottonwood leaf beetle, Chrysomela scripta F., is a serious defoliator of plantation Populus in the United States. Current control methods include biorational and synthetic chemicals as well as selecting Populus clones resistant or tolerant to C. scripta...

  17. Conservation and divergence of microRNAs in Populus

    PubMed Central

    Barakat, Abdelali; Wall, Phillip K; DiLoreto, Scott; dePamphilis, Claude W; Carlson, John E

    2007-01-01

    Background MicroRNAs (miRNAs) are small RNAs (sRNA) ~21 nucleotides in length that negatively control gene expression by cleaving or inhibiting the translation of target gene transcripts. miRNAs have been extensively analyzed in Arabidopsis and rice and partially investigated in other non-model plant species. To date, 109 and 62 miRNA families have been identified in Arabidopsis and rice respectively. However, only 33 miRNAs have been identified from the genome of the model tree species (Populus trichocarpa), of which 11 are Populus specific. The low number of miRNA families previously identified in Populus, compared with the number of families identified in Arabidopsis and rice, suggests that many miRNAs still remain to be discovered in Populus. In this study, we analyzed expressed small RNAs from leaves and vegetative buds of Populus using high throughput pyrosequencing. Results Analysis of almost eighty thousand small RNA reads allowed us to identify 123 new sequences belonging to previously identified miRNA families as well as 48 new miRNA families that could be Populus-specific. Comparison of the organization of miRNA families in Populus, Arabidopsis and rice showed that miRNA family sizes were generally expanded in Populus. The putative targets of non-conserved miRNA include both previously identified targets as well as several new putative target genes involved in development, resistance to stress, and other cellular processes. Moreover, almost half of the genes predicted to be targeted by non-conserved miRNAs appear to be Populus-specific. Comparative analyses showed that genes targeted by conserved and non-conserved miRNAs are biased mainly towards development, electron transport and signal transduction processes. Similar results were found for non-conserved miRNAs from Arabidopsis. Conclusion Our results suggest that while there is a conserved set of miRNAs among plant species, a large fraction of miRNAs vary among species. The non-conserved miRNAs may

  18. Variable Nitrogen Fixation in Wild Populus

    PubMed Central

    Doty, Sharon L.; Sher, Andrew W.; Fleck, Neil D.; Khorasani, Mahsa; Bumgarner, Roger E.; Khan, Zareen; Ko, Andrew W. K.; Kim, Soo-Hyung; DeLuca, Thomas H.

    2016-01-01

    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. PMID:27196608

  19. Characterization of DWARF14 Genes in Populus

    DOE PAGES

    Zheng, Kaijie; Wang, Xiaoping; Weighill, Deborah A.; ...

    2016-02-15

    Strigolactones are a new class of plant hormones regulating shoot branching and symbiotic interactions with arbuscular mycorrhizal fungi. Studies of branching mutants in herbaceous plants have identified several key genes involved in strigolactone biosynthesis or signaling. The strigolactone signal is perceived by a member of the α/β-fold hydrolase superfamily, known as DWARF14 (D14). However, little is known about D14 genes in the woody perennial plants. Here we report the identification of D14 homologs in the model woody plant Populus trichocarpa. We showed that there are two D14 homologs in P. trichocarpa, designated as PtD14a and PtD14b that are over 95%more » similar at the amino acid level. Expression analysis indicated that the transcript level of PtD14a is generally more abundant than that of PtD14b. However, only PtD14a was able to complement Arabidopsis d14 mutants, suggesting that PtD14a is the functional D14 ortholog. Amino acid alignment and structural modeling revealed substitutions of several highly conserved amino acids in the PtD14b protein including a phenylalanine near the catalytic triad of D14 proteins. Ultimately, we find this study lays a foundation for further characterization of strigolactone pathway and its functions in the woody perennial plants.« less

  20. Characterization of DWARF14 Genes in Populus

    SciTech Connect

    Zheng, Kaijie; Wang, Xiaoping; Weighill, Deborah A.; Guo, Hao-Bo; Xie, Meng; Yang, Yongil; Yang, Jun; Wang, Shucai; Jacobson, Daniel A.; Guo, Hong; Muchero, Wellington; Tuskan, Gerald A.; Chen, Jin-Gui

    2016-02-15

    Strigolactones are a new class of plant hormones regulating shoot branching and symbiotic interactions with arbuscular mycorrhizal fungi. Studies of branching mutants in herbaceous plants have identified several key genes involved in strigolactone biosynthesis or signaling. The strigolactone signal is perceived by a member of the α/β-fold hydrolase superfamily, known as DWARF14 (D14). However, little is known about D14 genes in the woody perennial plants. Here we report the identification of D14 homologs in the model woody plant Populus trichocarpa. We showed that there are two D14 homologs in P. trichocarpa, designated as PtD14a and PtD14b that are over 95% similar at the amino acid level. Expression analysis indicated that the transcript level of PtD14a is generally more abundant than that of PtD14b. However, only PtD14a was able to complement Arabidopsis d14 mutants, suggesting that PtD14a is the functional D14 ortholog. Amino acid alignment and structural modeling revealed substitutions of several highly conserved amino acids in the PtD14b protein including a phenylalanine near the catalytic triad of D14 proteins. Ultimately, we find this study lays a foundation for further characterization of strigolactone pathway and its functions in the woody perennial plants.

  1. Shotgun proteome profile of Populus developing xylem

    SciTech Connect

    Kalluri, Udaya C; Hurst, Gregory {Greg} B; Lankford, Patricia K; Ranjan, Priya; Pelletier, Dale A

    2009-01-01

    Understanding the molecular pathways of plant cell wall biosynthesis and remodeling is central to interpreting biological mechanisms underlying plant growth and adaptation as well as leveraging that knowledge towards development of improved bioenergy feedstocks. Here we report the application of shotgun tandem mass spectrometry profiling to the proteome of Populus developing xylem. Additionally, we mined public databases to obtain information in support of subcellular localization, transcript-level expression, and functional categorization of these proteins. Nearly 6000 different proteins were identified from the xylem proteome, with over 4400 proteins identified from one or more unique peptides. In addition to finding protein-level evidence of candidate wall biosynthesis genes from xylem (wood) tissue such as cellulose synthase, phenylalanine ammonia-lyase, and 4-coumarate:CoA ligase, several other potentially new candidate genes in the pathway were discovered. In order to identify low-abundance DNA-regulatory proteins from the developing xylem, a selective nuclear proteome profiling method was developed. Several putative transcription factor and chromatin remodeling proteins were identified using this method, such as LIM and NAC domain transcription factors and CHB3-SWI/SNF-related proteins. Further application of these proteomics methods will enhance understanding not only of cell wall biosynthesis in system biology modeling, but also other plant developmental and physiological pathways.

  2. Shotgun proteome profile of Populus developing xylem.

    PubMed

    Kalluri, Udaya C; Hurst, Gregory B; Lankford, Patricia K; Ranjan, Priya; Pelletier, Dale A

    2009-11-01

    Understanding the molecular pathways of plant cell wall biosynthesis and remodeling is central to interpreting biological mechanisms underlying plant growth and adaptation as well as leveraging that knowledge towards development of improved bioenergy feedstocks. Here, we report the application of shotgun MS/MS profiling to the proteome of Populus developing xylem. Nearly 6000 different proteins were identified from the xylem proteome. To identify low-abundance DNA-regulatory proteins from the developing xylem, a selective nuclear proteome profiling method was developed. Several putative transcription factors and chromatin remodeling proteins were identified using this method, such as NAC domain, CtCP-like and CHB3-SWI/SNF-related proteins. Public databases were mined to obtain information in support of subcellular localization, transcript-level expression and functional categorization of identified proteins. In addition to finding protein-level evidence of candidate cell wall biosynthesis genes from xylem (wood) tissue such as cellulose synthase, sucrose synthase and polygalacturonase, several other potentially new candidate genes in the cell wall biosynthesis pathway were discovered. Further application of such proteomics methods will aid in plant systems biology modeling efforts by enhancing the understanding not only of cell wall biosynthesis but also of other plant developmental and physiological pathways.

  3. Characterization of DWARF14 Genes in Populus

    PubMed Central

    Zheng, Kaijie; Wang, Xiaoping; Weighill, Deborah A.; Guo, Hao-Bo; Xie, Meng; Yang, Yongil; Yang, Jun; Wang, Shucai; Jacobson, Daniel A.; Guo, Hong; Muchero, Wellington; Tuskan, Gerald A.; Chen, Jin-Gui

    2016-01-01

    Strigolactones are a new class of plant hormones regulating shoot branching and symbiotic interactions with arbuscular mycorrhizal fungi. Studies of branching mutants in herbaceous plants have identified several key genes involved in strigolactone biosynthesis or signaling. The strigolactone signal is perceived by a member of the α/β-fold hydrolase superfamily, known as DWARF14 (D14). However, little is known about D14 genes in the woody perennial plants. Here we report the identification of D14 homologs in the model woody plant Populus trichocarpa. We showed that there are two D14 homologs in P. trichocarpa, designated as PtD14a and PtD14b that are over 95% similar at the amino acid level. Expression analysis indicated that the transcript level of PtD14a is generally more abundant than that of PtD14b. However, only PtD14a was able to complement Arabidopsis d14 mutants, suggesting that PtD14a is the functional D14 ortholog. Amino acid alignment and structural modeling revealed substitutions of several highly conserved amino acids in the PtD14b protein including a phenylalanine near the catalytic triad of D14 proteins. This study lays a foundation for further characterization of strigolactone pathway and its functions in the woody perennial plants. PMID:26875827

  4. Variable Nitrogen Fixation in Wild Populus.

    PubMed

    Doty, Sharon L; Sher, Andrew W; Fleck, Neil D; Khorasani, Mahsa; Bumgarner, Roger E; Khan, Zareen; Ko, Andrew W K; Kim, Soo-Hyung; DeLuca, Thomas H

    2016-01-01

    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.

  5. Defining hybrid poplar (Populus deltoides x Populus trichocarpa) tolerance to ozone: identifying key parameters.

    PubMed

    Ryan, A; Cojocariu, C; Possell, M; Davies, W J; Hewitt, C N

    2009-01-01

    This study examined whether two genotypes of hybrid poplar (Populus deltoides x Populus trichocarpa), previously classified as ozone tolerant and ozone sensitive, had differing physiological and biochemical responses when fumigated with 120 nL L(-1) ozone for 6 h per day for eight consecutive days. Isoprene emission rate, ozone uptake and a number of physiological and biochemical parameters were investigated before, during and after fumigation with ozone. Previous studies have shown that isoprene protects plants against oxidative stress. Therefore, it was hypothesized that these two genotypes would differ in either their basal isoprene emission rates or in the response of isoprene to fumigation by ozone. Our results showed that the basal emission rates of isoprene, physiological responses and ozone uptake rates were all similar. However, significant differences were found in visible damage, carotenoids, hydrogen peroxide (H(2)O(2)), thiobarbituric acid reactions (TBARS) and post-fumigation isoprene emission rates. It is shown that, although the classification of ozone tolerance or sensitivity had been previously clearly and carefully defined using one particular set of parameters, assessment of other key variables does not necessarily lead to the same conclusions. Thus, it may be necessary to reconsider the way in which plants are classified as ozone tolerant or sensitive.

  6. Evolutionary Quantitative Genomics of Populus trichocarpa

    PubMed Central

    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

  7. Evolutionary Quantitative Genomics of Populus trichocarpa.

    PubMed

    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

  8. Molecular linkage maps of the Populus genome.

    PubMed

    Yin, Tongming; Zhang, Xinye; Huang, Minren; Wang, Minxiu; Zhuge, Qiang; Tu, Shengming; Zhu, Li-Huang; Wu, Rongling

    2002-06-01

    We report molecular genetic linkage maps for an interspecific hybrid population of Populus, a model system in forest-tree biology. The hybrids were produced by crosses between P. deltoides (mother) and P. euramericana (father), which is a natural hybrid of P. deltoides (grandmother) and P. nigra (grandfather). Linkage analysis from 93 of the 450 backcross progeny grown in the field for 15 years was performed using random amplified polymorphic DNAs (RAPDs), amplified fragment length polymorphisms (AFLPs), and inter-simple sequence repeats (ISSRs). Of a total of 839 polymorphic markers identified, 560 (67%) were testcross markers heterozygous in one parent but null in the other (segregating 1:1), 206 (25%) were intercross dominant markers heterozygous in both parents (segregating 3:1), and the remaining 73 (9%) were 19 non-parental RAPD markers (segregating 1:1) and 54 codominant AFLP markers (segregating 1:1:1:1). A mixed set of the testcross markers, non-parental RAPD markers, and codominant AFLP markers was used to construct two linkage maps, one based on the P. deltoides (D) genome and the other based on P. euramericana (E). The two maps showed nearly complete coverage of the genome, spanning 3801 and 3452 cM, respectively. The availability of non-parental RAPD and codominant AFLP markers as orthologous genes allowed for a direct comparison of the rate of meiotic recombination between the two different parental species. Generally, the rate of meiotic recombination was greater for males than females in our interspecific poplar hybrids. The confounded effect of sexes and species causes the mean recombination distance of orthologous markers to be 11% longer for the father (P. euramericana; interspecific hybrid) than for the mother (P. deltoides; pure species). The linkage maps constructed and the interspecific poplar hybrid population in which clonal replicates for individual genotypes are available present a comprehensive foundation for future genomic studies and

  9. The glutamine synthetase gene family in Populus

    PubMed Central

    2011-01-01

    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. PMID:21867507

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

    SciTech Connect

    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.

  11. Overexpression of a CYP94 family gene CYP94C2b increases internode length and plant height in rice

    PubMed Central

    Kurotani, Ken-Ich; Hattori, Tsukaho; Takeda, Shin

    2015-01-01

    Plant growth is controlled by intrinsic developmental programmes and environmental cues. Jasmonate (JA) has important roles in both processes, by regulating cell division and differentiation, as well as in defense responses and senescence. We report an increase in rice plant height caused by overexpression of a gene encoding a cytochrome P450 enzyme, CYP94C2b, which promoted deactivation of JA-Ile. The height increase occurred through enhanced elongation of internodes in the absence of concomitant cell elongation, unlike previous findings with coi1 knock-down plants. Thus, modulating JA metabolism can increase the number of elongated cells in an internode. Based on these and previous findings, we discuss the difference in the effects of CYP94C2b overexpression vs. coi1 knock-down. PMID:26251886

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

    SciTech Connect

    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.

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

    SciTech Connect

    Tschaplinski, Timothy J; Davis, M F; Tuskan, Gerald A; Payne, M M; 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. & 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.

  14. Barley morphology, genetics and hormonal regulation of internode elongation modelled by a relational growth grammar.

    PubMed

    Buck-Sorlin, Gerhard H; Kniemeyer, Ole; Kurth, Winfried

    2005-06-01

    A multiscaled ecophysiological model of barley (Hordeum vulgare) development is presented here. The model is based on the new formalism of relational growth grammars (RGG), an extension of L-systems, and implemented using the new modelling language XL. It is executable in the interactive modelling platform GroIMP. The model consists of a set of morphogenetic rules, combined with a metabolic regulatory network, which simulates the biosynthesis of gibberellic acid (GA1). GA1 and two of its metabolic precursors are transported along the developing simulated structure. Local concentrations of GA1 determine internode elongation. Furthermore, virtual barley individuals are chosen interactively from a population, based on genotype, and (sexual or asexual) reproduction is simulated. Genotype and phenotype of the population are visualized. Seven Mendelian genes have been implemented in the model so far; some of these directly influence the GA-regulation network. The model exemplifies and validates the new formalism and modelling language. RGG have the capability to represent genetic, metabolic and morphological aspects of plant development and reproduction, all within the same framework.

  15. The excitability of plant cells: with a special emphasis on characean internodal cells

    NASA Technical Reports Server (NTRS)

    Wayne, R.

    1994-01-01

    This review describes the basic principles of electrophysiology using the generation of an action potential in characean internodal cells as a pedagogical tool. Electrophysiology has proven to be a powerful tool in understanding animal physiology and development, yet it has been virtually neglected in the study of plant physiology and development. This review is, in essence, a written account of my personal journey over the past five years to understand the basic principles of electrophysiology so that I can apply them to the study of plant physiology and development. My formal background is in classical botany and cell biology. I have learned electrophysiology by reading many books on physics written for the lay person and by talking informally with many patient biophysicists. I have written this review for the botanist who is unfamiliar with the basics of membrane biology but would like to know that she or he can become familiar with the latest information without much effort. I also wrote it for the neurophysiologist who is proficient in membrane biology but knows little about plant biology (but may want to teach one lecture on "plant action potentials"). And lastly, I wrote this for people interested in the history of science and how the studies of electrical and chemical communication in physiology and development progressed in the botanical and zoological disciplines.

  16. The excitability of plant cells: with a special emphasis on characean internodal cells

    NASA Technical Reports Server (NTRS)

    Wayne, R.

    1994-01-01

    This review describes the basic principles of electrophysiology using the generation of an action potential in characean internodal cells as a pedagogical tool. Electrophysiology has proven to be a powerful tool in understanding animal physiology and development, yet it has been virtually neglected in the study of plant physiology and development. This review is, in essence, a written account of my personal journey over the past five years to understand the basic principles of electrophysiology so that I can apply them to the study of plant physiology and development. My formal background is in classical botany and cell biology. I have learned electrophysiology by reading many books on physics written for the lay person and by talking informally with many patient biophysicists. I have written this review for the botanist who is unfamiliar with the basics of membrane biology but would like to know that she or he can become familiar with the latest information without much effort. I also wrote it for the neurophysiologist who is proficient in membrane biology but knows little about plant biology (but may want to teach one lecture on "plant action potentials"). And lastly, I wrote this for people interested in the history of science and how the studies of electrical and chemical communication in physiology and development progressed in the botanical and zoological disciplines.

  17. An efficient protocol for high-frequency direct multiple shoot regeneration from internodes of peppermint (Mentha x piperita).

    PubMed

    Thul, Sanjog T; Kukreja, Arun K

    2010-12-01

    A simple, repeatable and efficient protocol for direct multiple shoot regeneration from internodal explants has been defined in peppermint (Mentha x piperita var. Indus). In vitro regenerated shoots of peppermint were excised into 4 to 8 mm long internodes and cultured on Murashige and Skoog's medium supplemented with different cytokinins. In the hormonal assay, 3.0 mg L(-1) zeatin or 6-isopentenyl adenine independently supplemented to half strength MS medium exhibited multiple shoot regeneration, while thiaduzorn (0.1-3.0 mg L(-1)) showed no morphogenetic effect. A maximum of 85% in vitro cultured explants showed multiple shoot formation with an average of 7 shoots per explant on MS medium supplemented with zeatin. Multiple shoots were initiated within three weeks of cultivation. Internodes with regenerated multiple shoots were transferred to half- strength MS medium without supplementing with any plant growth hormone for shoot elongation and rhizogenesis. Rooted plants acclimatized and grew to maturity under glasshouse conditions. The plantlets developed were phenotypically identical to the parent plant and exhibited 96% survival.

  18. Effect of inhibitors of polyamine biosynthesis on gibberellin-induced internode growth in light-grown dwarf peas

    NASA Technical Reports Server (NTRS)

    Kaur-Sawhney, R.; Dai, Y. R.; Galston, A. W.

    1986-01-01

    When gibberellic acid (GA3) is sprayed on 9-day-old light-brown dwarf Progress pea (Pisum sativum) seedlings, arginine decarboxylase (ADC; EC 4.1.1.9) activity increases within 3 h and peaks at about 9 h after GA3 application. This is followed by a second lower peak at about 30 h; both peaks were higher than the corresponding peaks in the controls. In contrast, no appreciable effect of GA3 on internode length was observed until about 12 h, after which time a dramatic increase in growth rate occurred and persisted for about 12 h. Specific (DL-alpha-difluoromethylarginine) and non-specific (D-arginine and L-canavanine) inhibitors of ADC strongly inhibited ADC activity and to a lesser extent internode growth. The inhibition was reversed only slightly by the addition of polyamines. Actinomycin D and cycloheximide inhibited the rise in ADC activity induced by GA3. The half-life of the enzyme was increased by GA3 treatment. The results suggest that part of the GA3-induced increase in internode growth may result from enhanced polyamine biosynthesis through the ADC pathway. Furthermore, the GA3 induced increase in ADC activity probably requires de novo synthesis of both RNA and protein.

  19. Effect of inhibitors of polyamine biosynthesis on gibberellin-induced internode growth in light-grown dwarf peas

    NASA Technical Reports Server (NTRS)

    Kaur-Sawhney, R.; Dai, Y. R.; Galston, A. W.

    1986-01-01

    When gibberellic acid (GA3) is sprayed on 9-day-old light-brown dwarf Progress pea (Pisum sativum) seedlings, arginine decarboxylase (ADC; EC 4.1.1.9) activity increases within 3 h and peaks at about 9 h after GA3 application. This is followed by a second lower peak at about 30 h; both peaks were higher than the corresponding peaks in the controls. In contrast, no appreciable effect of GA3 on internode length was observed until about 12 h, after which time a dramatic increase in growth rate occurred and persisted for about 12 h. Specific (DL-alpha-difluoromethylarginine) and non-specific (D-arginine and L-canavanine) inhibitors of ADC strongly inhibited ADC activity and to a lesser extent internode growth. The inhibition was reversed only slightly by the addition of polyamines. Actinomycin D and cycloheximide inhibited the rise in ADC activity induced by GA3. The half-life of the enzyme was increased by GA3 treatment. The results suggest that part of the GA3-induced increase in internode growth may result from enhanced polyamine biosynthesis through the ADC pathway. Furthermore, the GA3 induced increase in ADC activity probably requires de novo synthesis of both RNA and protein.

  20. Genome structure and primitive sex chromosome revealed in Populus

    SciTech Connect

    Tuskan, Gerald A; Yin, Tongming; Gunter, Lee E; Blaudez, D

    2008-01-01

    We constructed a comprehensive genetic map for Populus and ordered 332 Mb of sequence scaffolds along the 19 haploid chromosomes in order to compare chromosomal regions among diverse members of the genus. These efforts lead us to conclude that chromosome XIX in Populus is evolving into a sex chromosome. Consistent segregation distortion in favor of the sub-genera Tacamahaca alleles provided evidence of divergent selection among species, particularly at the proximal end of chromosome XIX. A large microsatellite marker (SSR) cluster was detected in the distorted region even though the genome-wide distribute SSR sites was uniform across the physical map. The differences between the genetic map and physical sequence data suggested recombination suppression was occurring in the distorted region. A gender-determination locus and an overabundance of NBS-LRR genes were also co-located to the distorted region and were put forth as the cause for divergent selection and recombination suppression. This hypothesis was verified by using fine-scale mapping of an integrated scaffold in the vicinity of the gender-determination locus. As such it appears that chromosome XIX in Populus is in the process of evolving from an autosome into a sex chromosome and that NBS-LRR genes may play important role in the chromosomal diversification process in Populus.

  1. Successful grafting in poplar species (Populus spp.) breeding

    Treesearch

    A. Assibi Mahama; Brian Sparks; Ronald S., Zalesny; Richard B. Hall

    2006-01-01

    Poor rooting of Populus deltoides Bartr. ex Marsh hardwood cuttings often has contributed to delays in breeding progress as a result of failures of scion wood before and/or after pollination. Seventeen clones were used, and the study was conducted in the greenhouse to test an "intervenous feeding" (IV) method, along with three different...

  2. Creation and genomic analysis of irradiation hybrids in Populus

    Treesearch

    Matthew S. Zinkgraf; K. Haiby; M.C. Lieberman; L. Comai; I.M. Henry; Andrew Groover

    2016-01-01

    Establishing efficient functional genomic systems for creating and characterizing genetic variation in forest trees is challenging. Here we describe protocols for creating novel gene-dosage variation in Populus through gamma-irradiation of pollen, followed by genomic analysis to identify chromosomal regions that have been deleted or inserted in...

  3. Drought induces alterations in the stomatal development program in Populus.

    PubMed

    Hamanishi, Erin T; Thomas, Barb R; Campbell, Malcolm M

    2012-08-01

    Much is known about the physiological control of stomatal aperture as a means by which plants adjust to water availability. By contrast, the role played by the modulation of stomatal development to limit water loss has received much less attention. The control of stomatal development in response to water deprivation in the genus Populus is explored here. Drought induced declines in stomatal conductance as well as an alteration in stomatal development in two genotypes of Populus balsamifera. Leaves that developed under water-deficit conditions had lower stomatal indices than leaves that developed under well-watered conditions. Transcript abundance of genes that could hypothetically underpin drought-responsive changes in stomatal development was examined, in two genotypes, across six time points, under two conditions, well-watered and with water deficit. Populus homologues of STOMAGEN, ERECTA (ER), STOMATA DENSITY AND DISTRIBUTION 1 (SDD1), and FAMA had variable transcript abundance patterns congruent with their role in the modulation of stomatal development in response to drought. Conversely, there was no significant variation in transcript abundance between genotypes or treatments for the Populus homologues of YODA (YDA) and TOO MANY MOUTHS (TMM). The findings highlight the role that could be played by stomatal development during leaf expansion as a longer term means by which to limit water loss from leaves. Moreover, the results point to the key roles played by the regulation of the homologues of STOMAGEN, ER, SDD1, and FAMA in the control of this response in poplar.

  4. Herbicide Trials in Intensively Cultured Populus Plantations in Northern Wisconsin

    Treesearch

    Daniel A. Netzer; Nonan V. Noste

    1978-01-01

    Populus had good survival and growth when planting sites had been treated with linuron, a pre-emergent herbicide, alone or in combination with paraquat, a post-emergent herbicide. the herbicide treatments that are most effective in intensive culture are discussed.

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

    Treesearch

    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,...

  6. Shoot Morphogenesis Associated With Flowering in Populus deltoides (Salicaceae)

    Treesearch

    Cetin Yuceer; Samuel B. Land; Mark E. Kubiske; Richard L. Harkess

    2003-01-01

    Temporal and spatial formation and differentiation of axillary buds in developing shoots of mature eastern cottonwood (Populus deltoides) were investigated. Shoots sequentially initiate early vegetative, floral, and late vegetative buds. Associated with these buds is the formation of three distinct leaf types. In May of the first growing season, the...

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

    Treesearch

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

    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...

  8. Fine root dynamics in a developing Populus deltoides plantation

    Treesearch

    Christel C. Kern; Alexander L. Friend; Jane M.-F. Johnson; Mark D. Coleman

    2004-01-01

    A closely spaced (1 x 1 m) cottonwood (Populus deltoides Bartr.) plantation was established to evaluate the effects of nutrient availability on fine root dynamics. Slow-release fertilizer (17:6:12 N,P,K plus micronutrients) was applied to 225-m2 plots at 0,50,10O and 200 kg N ha-1, and plots were...

  9. Fine root dynamics in a developing Populus deltoides plantation

    Treesearch

    Christel C. Kern; Alexander L. Friend; Jane M. Johnson; Mark D. Coleman

    2004-01-01

    A closely spaced (1 x 1 m) cottonwood (Populus deltoides Bartr.) platation was established to evaluate the effects of nutrient availability on fine root dynamics. Slow-release fertilizer (17:6:12 N,P,K plus micronutrients) was applied to 225-m2 plots at 0, 50, 100, 200 kg N ha-1, and plots were monitored...

  10. Pathogenicity of Cytospora, Phomopsis, and Hypomyces on Populus deltoides

    Treesearch

    T. H. Filer

    1967-01-01

    Cytospora chrysosperma, Phomopsis macrospora, and Hypomyces solani are pathogenic on cottonwood (Populus deltoides). These canker-causing fungi were most virulent in November, when rains were frequent and temperatures were between 20 and 30 C. Trees growing on an unfavorable site were more susceptible to

  11. Genome-Wide Identification of miRNAs and Their Targets Involved in the Developing Internodes under Maize Ears by Responding to Hormone Signaling

    PubMed Central

    Yang, Huili; Li, Huimin; Sun, Gaoyang; Zhao, Xiaofeng; Ding, Dong; Tang, Jihua

    2016-01-01

    Internode length is one of the decisive factors affecting plant height (PH) and ear height (EH), which are closely associated with the lodging resistance, biomass and grain yield of maize. miRNAs, currently recognized as important transcriptional/ post-transcriptional regulators, play an essential role in plant growth and development. However, their roles in developing internodes under maize ears remain unclear. To identify the roles of miRNAs and their targets in the development of internodes under maize ears, six miRNA and two degradome libraries were constructed using the 7th, 8th and 9th internodes of two inbred lines, ‘Xun928’ and ‘Xun9058’, which had significantly different internode lengths. A total of 45 and 54 miRNAs showed significant changes for each pairwise comparison among the 7th, 8th and 9th internodes of ‘Xun9058’ and ‘Xun928’, respectively. The expression of 31 miRNAs showed significant changes were common to the corresponding comparison groups of the 7th, 8th and 9th internodes of ‘Xun9058’ and ‘Xun928’. For the corresponding internodes of ‘Xun9058’ and ‘Xun928’, compared with the expression of miRNAs in the 7th, 8th and 9th internodes of ‘Xun928’, the numbers of up-regulated and down-regulated miRNAs were 11 and 36 in the 7th internode, 9 and 45 in the 8th internode, and 9 and 25 in the 9th internode of ‘Xun9058’, respectively. Moreover, 10 miRNA families containing 45 members showed significant changes at least in two internodes of ‘Xun928’ by comparing with the corresponding internodes of ‘Xun9058’. Based on the sequencing data, 20 miRNAs related to hormone signaling among the candidates, belonging to five conserved miRNA families, were selected for expression profiling using quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The five miRNA families, zma-miR160, zma-miR167, zma-miR164, zma-miR169 and zma-miR393, targeted the genes encoding auxin response factor, N

  12. Uncoupling light quality from light irradiance effects in Helianthus annuus shoots: putative roles for plant hormones in leaf and internode growth.

    PubMed

    Kurepin, Leonid V; Emery, R J Neil; Pharis, Richard P; Reid, David M

    2007-01-01

    An attempt has been made to uncouple the effects of the two primary components of shade light, a reduced red to far-red (R/FR) ratio and low photosynthetically active radiation (PAR), on the elongation of the youngest internode of sunflower (Helianthus annuus) seedlings. Maximal internode growth (length and biomass) was induced by a shade light having a reduced R/FR ratio (0.85) under the low PAR of 157 micromol m(-2) s(-1). Reducing the R/FR ratio under normal PAR (421 micromol m(-2) s(-1)) gave similar growth trends, albeit with a reduced magnitude of the response. Leaf area growth showed a rather different pattern, with maximal growth occurring at the higher (normal) PAR of 421 micromol m(-2) s(-1)), but with variable effects being seen with changes in light quality. Reducing the R/FR ratio (by enrichment with FR) gave significant increases in gibberellin A(1) (GA(1)) and indole-3-acetic acid (IAA) contents in both internodes and leaves. By contrast, a lower PAR irradiance had no significant effect on GA(1) and IAA levels in internodes or leaves, but did increase the levels of other GAs, including two precursors of GA(1). Interestingly, both leaf and internode hormone content (GAs, IAA) are positively and significantly correlated with growth of the internode, as are leaf levels of abscisic acid (ABA). However, changes in these three hormones bear little relationship to leaf growth. By implication, then, the leaf may be the major source of GAs and IAA, at least, for the rapidly elongating internode. Several other hormones were also assessed in leaves for plants grown under varying R/FR ratios and PARs. Leaf ethylene production was not influenced by changes in R/FR ratio, but was significantly reduced under the normal (higher) PAR, the irradiance treatment which increased leaf growth. Levels of the growth-active free base and riboside cytokinins were significantly increased in leaves under a reduced R/FR ratio, but only at the higher (normal) PAR irradiance; other

  13. Rapid auxin-induced stimulation of cell wall synthesis in pea internodes

    SciTech Connect

    Kutschera, U.; Briggs, W.R.

    1987-05-01

    The effect of auxin (indole-3-acetic acid; IAA) on growth and incorporation of myo-(2-/sup 3/H(N)) inositol ((/sup 3/H)Ins) into noncellulosic polysacchharides in the cell walls of third internode sections from red light-grown pea seedlings (Pisum sativum L. cv. Alaska) was investigated. Intact section were incubated on (/sup 3/H)Ins for 4 hr to permit uptake of the tracer and then IAA was added. Growth started after a lag phase of 15 min under these conditions. The sections were removed from the tracer and separated into epidermis and cortical cylinder (cortex plus vascular tissue). In the epidermis, IAA-induced stimulation of (/sup 3/H)Ins incorporation started after a lag of 15 min. The amount of incorporation was 15% higher after 30 min and 24% higher after 2 hr than in the control. In the cortical cylinder, IAA-induced stimulation of (/sup 3/H)Ins incorporation started only approx. = 1 hr after adding IAA. The ionophore monensin (20 ..mu..M) inhibited the IAA-induced growth by 95%. Under these conditions, the IAA-induced stimulation of (/sup 3/H)Ins incorporation and the IAA-induced increase in in vivo extensibility of the sections was almost completely inhibited, although oxygen uptake was unaffected. The authors suggest that wall synthesis (as represented by (/sup 3/H)Ins incorporation) and wall loosening (increase in in vivo extensibility) are related processes. The results support the hypothesis that IAA induces growth by rapid simulation of cell wall synthesis in the growth-limiting epidermal cell layer.

  14. Physical basis for altered stem elongation rates in internode length mutants of Pisum

    NASA Technical Reports Server (NTRS)

    Behringer, F. J.; Cosgrove, D. J.; Reid, J. B.; Davies, P. J.

    1990-01-01

    Biophysical parameters related to gibberellin (GA)-dependent stem elongation were examined in dark-grown stem-length genotypes of Pisum sativum L. The rate of internode expansion in these genotypes is altered due to recessive mutations which affect either the endogenous levels of, or response to, GA. The GA deficient dwarf L181 (ls), two GA insensitive semierectoides dwarfs NGB5865 and NGB5862 (lka and lkb, respectively) and the slender' line L197 (la crys), which is tall regardless of GA content, were compared to the wild-type tall cultivar, Torsdag. Osmotic pressure, estimated by vapor pressure osmometry, and turgor pressure, measured directly with a pressure probe, did not correlate with the differences in growth rate among the genotypes. Mechanical wall properties of frozen-thawed tissue were measured using a constant force assay. GA deficiency resulted in increased wall stiffness judged both on the basis of plastic compliance and plastic extensibility normalized for equal stem circumference. Plastic compliance was not reduced in the GA insensitive dwarfs, though lka reduced circumference-normalized plasticity. In contrast, in vivo wall relaxation, determined by the pressure-block technique, differed among genotypes in a manner which did correlate with extension rates. The wall yield threshold was 1 bar or less in the tall lines, but ranged from 3 to 6 bars in the dwarf genotypes. The results with the ls mutant indicate that GA enhances stem elongation by both decreasing the wall yield threshold and increasing the wall yield coefficient. In the GA-insensitive mutants, lka and lkb, the wall yield threshold is substantially elevated. Plants possessing lka may also possess a reduced wall yield coefficient.

  15. Physical basis for altered stem elongation rates in internode length mutants of Pisum

    SciTech Connect

    Behringer, F.J.; Davies, P.J. ); Cosgrove, D.J. ); Reid, J.B. )

    1990-09-01

    Biophysical parameters related to gibberellin (GA)-dependent stem elongation were examined in dark-grown stem-length genotypes of Pisum sativum L. The rate of internode expansion in these genotypes is altered due to recessive mutations which affect either the endogenous levels of, or response to, GA. The GA deficient dwarf L181 (ls), two GA insensitive semierectoides dwarfs NGB5865 and NGB5862 (lka and lkb, respectively) and the slender line L197 (la cry{sup s}), which is tall regardless of GA content, were compared to the wild-type tall cultivar, Torsdag. Osmotic pressure, estimated by vapor pressure osmometry, and turgor pressure, measured directly with a pressure probe, did not correlate with the differences in growth rate among the genotypes. Mechanical wall properties of frozen-thawed tissue were measured using a constant force assay. GA deficiency resulted in increased wall stiffness judged both on the basis of plastic compliance and plastic extensibility normalized for equal stem circumference. Plastic compliance was not reduced in the GA insensitive dwarfs, though lka reduced circumference-normalized plasticity. In contrast, in vivo wall relaxation, determined by the pressure-block technique, differed among genotypes in a manner which did correlate with extension rates. The wall yield threshold was 1 bar or less in the tall lines, but ranged from 3 to 6 bars in the dwarf genotypes. The results with the ls mutant indicate that GA enhances stem elongation by both decreasing the wall yield threshold and increasing the wall yield coefficient. In the GA-insensitive mutants, lka and lkb, the wall yield threshold is substantially elevated. Plants possessing lka may also possess a reduced wall yield coefficient.

  16. Overexpression of LEAFY in apple leads to a columnar phenotype with shorter internodes.

    PubMed

    Flachowsky, Henryk; Hättasch, Conny; Höfer, Monika; Peil, Andreas; Hanke, Magda-Viola

    2010-01-01

    To break the juvenile stage of apple (Malus x domestica Borkh.) we transferred the LFY gene of Arabidopsis into the genome of the apple cv. 'Pinova'. A total of five transgenic clones constitutively overexpressing the LFY gene were obtained. Approximately, 20 shoots of each clone were rooted and transferred to the glasshouse. No flowers were obtained on transgenic plants during the first 2 years of cultivation. Evaluation of the expression of possible LFY targets revealed that no transcripts could be detected for MdAP1-1 and MdAP1-2. MdTFL1 was unaffected. Based on the absence of the LFY core-binding sequence within promoter sequences of MdAP1-1 and MdAP1-2, it was concluded that LFY was not able to induce these genes. The LFY genes of apple were unaffected in transgenic plants and sequence alignments of the C-terminal amino acid sequence showed a high conservation of these proteins. A change in binding ability to DNA can therefore be excluded. Instead of early flowering, the transgenic plants showed an altered phenotype, which is similar to the columnar phenotype of the 'McIntosh Wijcik' mutant of apple. The transgenic plants showed shortened internodes and a significantly reduced length of the regrowing shoot. A negative correlation was observed between the length of the regrowing shoot and the LFY mRNA transcript level. Furthermore, the LFY transgenic apple plants showed an increased shoot diameter at node 20, which was positively correlated with the LFY mRNA transcript level. Based on our results, we assume an alternative role of LFY in apple.

  17. The characean internodal cell as a model system for studying wound healing

    PubMed Central

    Foissner, I.; Wasteneys, G.O.

    2012-01-01

    Summary This work describes the characean internodal cell as a model system for the study of wound healing and compares wounds induced by certain chemicals and UV irradiation with wounds occurring in the natural environment. We review the existing literature and define three types of wound response: 1) cortical window formation characterized by disassembly of microtubules, transient inhibition of actin-dependent cytoplasmic streaming and chloroplast detachment, 2) fibrillar wound walls characterized by exocytosis of vesicles carrying wall polysaccharides and membrane-bound cellulose synthase complexes coupled with endocytosis of surplus membrane and 3) amorphous, callose- and membrane-containing wound walls characterized by exocytosis of vesicles and endoplasmic reticulum (ER) cisternae in the absence of membrane recycling. We hypothesize that these three wound responses reflect the extent of damage, probably Ca2+ influx, and that the secretion of Ca2+ - loaded ER cisternae is an emergency reaction in case of severe Ca2+ load. Microtubules are not required for wound healing but their disassembly could have a signalling function. Transient reorganization of the actin cytoskeleton into a meshwork of randomly oriented filaments is required for the migration of wound wall forming organelles, just as occurs in tip-growing plant cells. New data presented in this study show that during the deposition of an amorphous wound wall numerous actin rings are present, which may indicate specific ion fluxes and/or a storage form for actin. In addition, we present new evidence for the exocytosis of FM1-43-stained organelles, putative endosomes, required for plasma membrane repair during wound healing. Finally we show that quickly growing fibrillar wound walls, even when deposited in the absence of microtubules, have a highly ordered helical structure of consistent handedness comprised of cellulose microfibrils. PMID:22118365

  18. Differential effect of auxin on in vivo extensibility of cortical cylinder and epidermis in pea internodes.

    PubMed

    Kutschera, U; Briggs, W R

    1987-08-01

    The effect of auxin indole-3-acetic acid (IAA) on growth and in vivo extensibility of third internode sections from red light grown pea seedlings (Pisum sativum L. cv Alaska) and the isolated tissues (cortex plus vascular tissue = cortical cylinder, and epidermis) was investigated. Living tissue was stretched at constant force (creep test) in a custom-built extensiometer. In the intact section, IAA-induced increase in total (E(tot)), elastic (E(el)), and plastic (E(pl)) extensibility is closely related to the growth rate. The extensibility of the cortical cylinder, measured immediately after peeling of intact sections incubated for 4 hours in IAA, is not increased by IAA. Epidermal strips, peeled from growing sections incubated in IAA, show a E(pl) increase, which is correlated to the growth rate of the intact segments. The isolated cortical cylinder expands in water; IAA has only a small growth-promoting effect. The extensibility of the cortical cylinder is not increased by IAA. Epidermal strips contract about 10% on isolation. When incubated in IAA, they do not elongate, but respond with an E(pl) increase. The amount of expansion of the cortical cylinder and contraction of the epidermis (tissue tension), measured immediately following excision and peeling, stays constant during IAA-induced growth of intact sections. The results support the hypothesis that IAA induces growth of the intact section by causing an E(pl) increase of the outer epidermal wall. The driving force comes from the expansion of the cortical cylinder which is under constant compression in the intact section.

  19. Physical basis for altered stem elongation rates in internode length mutants of Pisum.

    PubMed

    Behringer, F J; Cosgrove, D J; Reid, J B; Davies, P J

    1990-01-01

    Biophysical parameters related to gibberellin (GA)-dependent stem elongation were examined in dark-grown stem-length genotypes of Pisum sativum L. The rate of internode expansion in these genotypes is altered due to recessive mutations which affect either the endogenous levels of, or response to, GA. The GA deficient dwarf L181 (ls), two GA insensitive semierectoides dwarfs NGB5865 and NGB5862 (lka and lkb, respectively) and the slender' line L197 (la crys), which is tall regardless of GA content, were compared to the wild-type tall cultivar, Torsdag. Osmotic pressure, estimated by vapor pressure osmometry, and turgor pressure, measured directly with a pressure probe, did not correlate with the differences in growth rate among the genotypes. Mechanical wall properties of frozen-thawed tissue were measured using a constant force assay. GA deficiency resulted in increased wall stiffness judged both on the basis of plastic compliance and plastic extensibility normalized for equal stem circumference. Plastic compliance was not reduced in the GA insensitive dwarfs, though lka reduced circumference-normalized plasticity. In contrast, in vivo wall relaxation, determined by the pressure-block technique, differed among genotypes in a manner which did correlate with extension rates. The wall yield threshold was 1 bar or less in the tall lines, but ranged from 3 to 6 bars in the dwarf genotypes. The results with the ls mutant indicate that GA enhances stem elongation by both decreasing the wall yield threshold and increasing the wall yield coefficient. In the GA-insensitive mutants, lka and lkb, the wall yield threshold is substantially elevated. Plants possessing lka may also possess a reduced wall yield coefficient.

  20. Physical basis for altered stem elongation rates in internode length mutants of Pisum

    NASA Technical Reports Server (NTRS)

    Behringer, F. J.; Cosgrove, D. J.; Reid, J. B.; Davies, P. J.

    1990-01-01

    Biophysical parameters related to gibberellin (GA)-dependent stem elongation were examined in dark-grown stem-length genotypes of Pisum sativum L. The rate of internode expansion in these genotypes is altered due to recessive mutations which affect either the endogenous levels of, or response to, GA. The GA deficient dwarf L181 (ls), two GA insensitive semierectoides dwarfs NGB5865 and NGB5862 (lka and lkb, respectively) and the slender' line L197 (la crys), which is tall regardless of GA content, were compared to the wild-type tall cultivar, Torsdag. Osmotic pressure, estimated by vapor pressure osmometry, and turgor pressure, measured directly with a pressure probe, did not correlate with the differences in growth rate among the genotypes. Mechanical wall properties of frozen-thawed tissue were measured using a constant force assay. GA deficiency resulted in increased wall stiffness judged both on the basis of plastic compliance and plastic extensibility normalized for equal stem circumference. Plastic compliance was not reduced in the GA insensitive dwarfs, though lka reduced circumference-normalized plasticity. In contrast, in vivo wall relaxation, determined by the pressure-block technique, differed among genotypes in a manner which did correlate with extension rates. The wall yield threshold was 1 bar or less in the tall lines, but ranged from 3 to 6 bars in the dwarf genotypes. The results with the ls mutant indicate that GA enhances stem elongation by both decreasing the wall yield threshold and increasing the wall yield coefficient. In the GA-insensitive mutants, lka and lkb, the wall yield threshold is substantially elevated. Plants possessing lka may also possess a reduced wall yield coefficient.

  1. Plasma Membrane Domains Participate in pH Banding of Chara Internodal Cells

    PubMed Central

    Schmölzer, Patric M.; Höftberger, Margit; Foissner, Ilse

    2011-01-01

    We investigated the identity and distribution of cortical domains, stained by the endocytic marker FM 1-43, in branchlet internodal cells of the characean green algae Chara corallina and Chara braunii. Co-labeling with NBD C6-sphingomyelin, a plasma membrane dye, which is not internalized, confirmed their location in the plasma membrane, and co-labelling with the fluorescent pH indicator Lysotracker red indicated an acidic environment. The plasma membrane domains co-localized with the distribution of an antibody against a proton-translocating ATPase, and electron microscopic data confirmed their identity with elaborate plasma membrane invaginations known as charasomes. The average size and the distribution pattern of charasomes correlated with the pH banding pattern of the cell. Charasomes were larger and more frequent at the acidic regions than at the alkaline bands, indicating that they are involved in outward-directed proton transport. Inhibition of photosynthesis by DCMU prevented charasome formation, and incubation in pH buffers resulted in smaller, homogenously distributed charasomes irrespective of whether the pH was clamped at 5.5 or 8.5. These data indicate that the differential size and distribution of charasomes is not due to differences in external pH but reflects active, photosynthesis-dependent pH banding. The fact that pH banding recovered within several minutes in unbuffered medium, however, confirms that pH banding is also possible in cells with evenly distributed charasomes or without charasomes. Cortical mitochondria were also larger and more abundant at the acid bands, and their intimate association with charasomes and chloroplasts suggests an involvement in carbon uptake and photorespiration. PMID:21659328

  2. Shortened internodal length of dermal myelinated nerve fibres in Charcot–Marie-Tooth disease type 1A

    PubMed Central

    Saporta, Mario A.; Katona, Istvan; Lewis, Richard A.; Masse, Stacey; Shy, Michael E.

    2009-01-01

    Charcot–Marie-Tooth disease type 1A is the most common inherited neuropathy and is caused by duplication of chromosome 17p11.2 containing the peripheral myelin protein-22 gene. This disease is characterized by uniform slowing of conduction velocities and secondary axonal loss, which are in contrast with non-uniform slowing of conduction velocities in acquired demyelinating disorders, such as chronic inflammatory demyelinating polyradiculoneuropathy. Mechanisms responsible for the slowed conduction velocities and axonal loss in Charcot–Marie-Tooth disease type 1A are poorly understood, in part because of the difficulty in obtaining nerve samples from patients, due to the invasive nature of nerve biopsies. We have utilized glabrous skin biopsies, a minimally invasive procedure, to evaluate these issues systematically in patients with Charcot–Marie-Tooth disease type 1A (n = 32), chronic inflammatory demyelinating polyradiculoneuropathy (n = 4) and healthy controls (n = 12). Morphology and molecular architecture of dermal myelinated nerve fibres were examined using immunohistochemistry and electron microscopy. Internodal length was uniformly shortened in patients with Charcot–Marie-Tooth disease type 1A, compared with those in normal controls (P < 0.0001). Segmental demyelination was absent in the Charcot–Marie-Tooth disease type 1A group, but identifiable in all patients with chronic inflammatory demyelinating polyradiculoneuropathy. Axonal loss was measurable using the density of Meissner corpuscles and associated with an accumulation of intra-axonal mitochondria. Our study demonstrates that skin biopsy can reveal pathological and molecular architectural changes that distinguish inherited from acquired demyelinating neuropathies. Uniformly shortened internodal length in Charcot–Marie-Tooth disease type 1A suggests a potential developmental defect of internodal lengthening. Intra-axonal accumulation of mitochondria provides new insights into the

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

    SciTech Connect

    DeBell, D.S.; Harrington, C.A.; Clendenen, G.W.; Radwan, M.A.; Zasada, J.C.

    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.

  4. Hormonal and gravitropic specificity in the regulation of growth and cell wall synthesis in pulvini and internodes from shoots of Avena sativa L. (oat).

    PubMed Central

    Montague, M J

    1995-01-01

    Segments can be cut from the peduncular-1 internode of oat (Avena sativa L.) shoots so as to contain the graviresponsive leaf-sheath pulvinus and gibberellin-sensitive internodal tissue. Incorporation of [14C]glucose was used to monitor cell wall synthesis in these two tissues as affected by gravistimulus, indoleacetic acid (IAA), gibberellic acid (GA3), and fusicoccin (FC). Pulvinar cell wall synthesis was promoted by IAA and FC (both within about 1 h), as well as by gravistimulus (starting between 3 and 6 h), whereas GA3 had no effect on nongravistimulated pulvini. In contrast, GA3 and FC promoted internodal cell wall synthesis (initiated between 1 and 2 h), whereas IAA and gravistimulus caused a decrease in internodal uptake. FC preferentially promoted incorporation into the matrix component of the wall in both tissues. Gravistimulus failed to increase responsiveness of pulvinar tissue to IAA, whereas GA3 partially overcame gravistimulus-promoted incorporation into pulvinar cell wall, probably because of preferential movement of label into the rapidly elongating internode. The results demonstrate that these eight stimulus/tissue combinations can be examined easily in an isolated 10-mm stem segment, providing new opportunities for the comparative study of tissue- and stimulus-specific events in gene regulation and signal transduction in agronomically important cereals. PMID:11536686

  5. Using Populus as a lignocellulosic feedstock for bioethanol.

    PubMed

    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.

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

    PubMed Central

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

    2001-01-01

    Cinnamic acid 4-hydroxylase (C4H), a member of the cytochrome P450 monooxygenase superfamily, plays a central role in phenylpropanoid metabolism and lignin biosynthesis and possibly anchors a phenylpropanoid enzyme complex to the endoplasmic reticulum (ER). A full-length cDNA encoding C4H was isolated from a hybrid poplar (Populus trichocarpa × P. deltoides) young leaf cDNA library. RNA-blot analysis detected C4H transcripts in all organs tested, but the gene was most highly expressed in developing xylem. C4H expression was also strongly induced by elicitor-treatment in poplar cell cultures. To verify the catalytic activity of the putative C4H cDNA, two constructs, C4H and C4H fused to the FLAG epitope (C4H::FLAG), were expressed in yeast. Immunoblot analysis showed that C4H was present in the microsomal fraction and microsomal preparations from strains expressing both enzymes efficiently converted cinnamic acid to p-coumaric acid with high specific activities. To investigate the subcellular localization of C4H in vivo, a chimeric C4H-green fluorescent protein (GFP) gene was engineered and stably expressed in Arabidopsis. Confocal laser microscopy analysis clearly showed that in Arabidopsis the C4H::GFP chimeric enzyme was localized to the ER. When expressed in yeast, the C4H::GFP fusion enzyme was also active but displayed significantly lower specific activity than either C4H or C4H::FLAG in in vitro and in vivo enzyme assays. These data definitively show that C4H is localized to the ER in planta. PMID:11351095

  7. 14C/C measurements support Andreev's internode method to determine lichen growth rates in Cladina stygia (Fr.) Ahti

    SciTech Connect

    Holt, E; Bench, G

    2007-12-05

    Growth rates and the ability to date an organism can greatly contribute to understanding its population biology and community dynamics. 1n 1954, Andreev proposed a method to date Cladina, a fruticose lichen, using total thallus length and number of internodes. No research, however, has demonstrated the reliability of this technique or compared its estimates to those derived by other means. In this study, we demonstrate the utility of {sup 14}C/C ratios to determine lichen age and growth rate in Cladina stygia (Fr.) Ahti collected from northwestern Alaska, USA. The average growth rate using {sup 14}C/C ratios was 6.5 mm {center_dot} yr{sup -1}, which was not significantly different from growth rates derived by Andreev's internode method (average = 6.2 mm {center_dot} yr{sup -1}); thus, suggesting the reliability of Andreev's simple field method for dating lichens. In addition, we found lichen growth rates appeared to differ with geographic location, yet did not seem related to ambient temperature and total precipitation.

  8. Rice HOX12 Regulates Panicle Exsertion by Directly Modulating the Expression of ELONGATED UPPERMOST INTERNODE1[OPEN

    PubMed Central

    Gao, Shaopei; Fang, Jun; Xu, Fan; Wang, Wei

    2016-01-01

    Bioactive gibberellins (GAs) are key endogenous regulators of plant growth. Previous work identified ELONGATED UPPERMOST INTERNODE1 (EUI1) as a GA-deactivating enzyme that plays an important role in panicle exsertion from the flag leaf sheath in rice (Oryza sativa). However, the mechanism that regulates EUI1 activity during development is still largely unexplored. In this study, we identified the dominant panicle enclosure mutant regulator of eui1 (ree1-D), whose phenotype is caused by the activation of the homeodomain-leucine zipper transcription factor HOX12. Diminished HOX12 expression by RNA interference enhanced panicle exsertion, mimicking the eui1 phenotype. HOX12 knockdown plants contain higher levels of the major biologically active GAs (such as GA1 and GA4) than the wild type. The expression of EUI1 is elevated in the ree1-D mutant but reduced in HOX12 knockdown plants. Interestingly, both HOX12 and EUI1 are predominantly expressed in panicles, where GA4 is highly accumulated. Yeast one-hybrid, electrophoretic mobility shift assay, and chromatin immunoprecipitation analyses showed that HOX12 physically interacts with the EUI1 promoter both in vitro and in vivo. Furthermore, plants overexpressing HOX12 in the eui1 mutant background retained the elongated uppermost internode phenotype. These results indicate that HOX12 acts directly through EUI1 to regulate panicle exsertion in rice. PMID:26977084

  9. Loss of function of a rice brassinosteroid insensitive1 homolog prevents internode elongation and bending of the lamina joint.

    PubMed

    Yamamuro, C; Ihara, Y; Wu, X; Noguchi, T; Fujioka, S; Takatsuto, S; Ashikari, M; Kitano, H; Matsuoka, M

    2000-09-01

    Brassinosteroids (BRs) are plant growth-promoting natural products required for plant growth and development. Physiological studies have demonstrated that exogenous BR, alone or in combination with auxin, enhance bending of the lamina joint of rice. However, little is known about the function of endogenous BR in rice or other grass species. We report here the phenotypical and molecular characterization of a rice dwarf mutant, d61, that is less sensitive to BR compared to the wild type. We cloned a rice gene, OsBRI1, with extensive sequence similarity to that of the Arabidopsis BRI gene, which encodes a putative BR receptor kinase. Linkage analysis showed that the OsBRI1 gene is closely linked to the d61 locus. Single nucleotide substitutions found at different sites of the d61 alleles would give rise to amino acid changes in the corresponding polypeptides. Furthermore, introduction of the entire OsBRI1 coding region, including the 5' and 3' flanking sequences, into d61 plants complemented the mutation to display the wild-type phenotype. Transgenic plants carrying the antisense strand of the OsBRI1 transcript showed similar or even more severe phenotypes than those of the d61 mutants. Our results show that OsBRI1 functions in various growth and developmental processes in rice, including (1) internode elongation, by inducing the formation of the intercalary meristem and the longitudinal elongation of internode cells; (2) bending of the lamina joint; and (3) skotomorphogenesis.

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

    Treesearch

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

    Treesearch

    David R. Coyle; Mark D. Coleman; Jaclin A. Durant; Lee A. Newman

    2006-01-01

    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...

  12. Genetic and environmental factors affecting early rooting of six Populus genomic groups: implications for tree improvement

    Treesearch

    Ronald S., Jr. Zalesny

    2006-01-01

    Genetic and environmental factors affect the early rooting of Populus planted as unrooted hardwood cuttings. Populus genotypes of six genomic groups were tested in numerous studies for the quantitative genetics of rooting, along with effects of preplanting treatments and soil temperature. Genetics data (e.g. heritabilities,...

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

    Treesearch

    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...

  14. Leaf, woody, and root biomass of Populus irrigated with landfill leachate

    Treesearch

    Jill A. Zalesny; Ronald S., Jr. Zalesny; D.R. Coyle; R.B. Hall

    2007-01-01

    Poplar (Populus spp.) trees can be utilized for ecological leachate disposal when applied as an irrigation source for managed tree systems. Our objective was to evaluate differences in tree height, diameter, volume, and biomass of leaf, stem, branch, and root tissues of Populus trees after two seasons of irrigation with municipal...

  15. Alternative splicing and gene duplication differentially shaped the regulation of isochorismate synthase in Populus and Arabidopsis

    PubMed Central

    Yuan, Yinan; Chung, Jeng-Der; Fu, Xueyan; Johnson, Virgil E.; Ranjan, Priya; Booth, Sarah L.; Harding, Scott A.; Tsai, Chung-Jui

    2009-01-01

    Isochorismate synthase (ICS) converts chorismate to isochorismate for the biosynthesis of phylloquinone, an essential cofactor for photosynthetic electron transport. ICS is also required for salicylic acid (SA) synthesis during Arabidopsis defense. In several other species, including Populus, SA is derived primarily from the phenylpropanoid pathway. We therefore sought to investigate ICS regulation in Populus to learn the extent of ICS involvement in SA synthesis and defense. Arabidopsis harbors duplicated AtICS genes that differ in their exon-intron structure, basal expression, and stress inducibility. In contrast, we found a single ICS gene in Populus and six other sequenced plant genomes, pointing to the AtICS duplication as a lineage-specific event. The Populus ICS encodes a functional plastidic enzyme, and was not responsive to stresses that stimulated phenylpropanoid accumulation. Populus ICS underwent extensive alternative splicing that was rare for the duplicated AtICSs. Sequencing of 184 RT-PCR Populus clones revealed 37 alternative splice variants, with normal transcripts representing ≈50% of the population. When expressed in Arabidopsis, Populus ICS again underwent alternative splicing, but did not produce normal transcripts to complement AtICS1 function. The splice-site sequences of Populus ICS are unusual, suggesting a causal link between junction sequence, alternative splicing, and ICS function. We propose that gene duplication and alternative splicing of ICS evolved independently in Arabidopsis and Populus in accordance with their distinct defense strategies. AtICS1 represents a divergent isoform for inducible SA synthesis during defense. Populus ICS primarily functions in phylloquinone biosynthesis, a process that can be sustained at low ICS transcript levels. PMID:19996170

  16. Comparative nucleotide diversity across North American and European populus species.

    PubMed

    Ismail, Mohamed; Soolanayakanahally, Raju Y; Ingvarsson, Pär K; Guy, Robert D; Jansson, Stefan; Silim, Salim N; El-Kassaby, Yousry A

    2012-06-01

    Nucleotide polymorphisms in two North American balsam poplars (Populus trichocarpa Torr. & Gray and P. balsamifera L.; section Tacamahaca), and one Eurasian aspen (P. tremula L.; section Populus) were compared using nine loci involved in defense, stress response, photoperiodism, freezing tolerance, and housekeeping. Nucleotide diversity varied among species and was highest for P. tremula (θ(w) = 0.005, π(T) = 0.007) as compared to P. balsamifera (θ(w) = 0.004, π(T) = 0.005) or P. trichocarpa (θ(w) = 0.002, π(T) = 0.003). Across species, the defense and the stress response loci accounted for the majority of the observed level of nucleotide diversity. In general, the studied loci did not deviate from neutral expectation either at the individual locus (non-significant normalized Fay and Wu's H) or at the multi-locus level (non-significant HKA test). Using molecular clock analysis, section Tacamahaca probably shared a common ancestor with section Populus approximately 4.5 million year ago. Divergence between the two closely related balsam poplars was about 0.8 million years ago, a pattern consistent with an isolation-with-migration (IM) model. As expected, P. tremula showed a five-fold higher substitution rate (2 × 10(-8) substitution/site/year) compared to the North American species (0.4 × 10(-8) substitution/site/year), probably reflecting its complex demographic history. Linkage disequilibrium (LD) varied among species with a more rapid decay in the North American species (<400 bp) in comparison to P. tremula (≫400 bp). The similarities in nucleotide diversity pattern and LD decay of the two balsam poplar species likely reflects the recent time of their divergence.

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

    PubMed

    Zhang, Qun-jie; Gao, Li-zhi

    2016-01-01

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

  18. ELONGATED UPPERMOST INTERNODE Encodes a Cytochrome P450 Monooxygenase That Epoxidizes Gibberellins in a Novel Deactivation Reaction in RiceW⃞

    PubMed Central

    Zhu, Yongyou; Nomura, Takahito; Xu, Yonghan; Zhang, Yingying; Peng, Yu; Mao, Bizeng; Hanada, Atsushi; Zhou, Haicheng; Wang, Renxiao; Li, Peijin; Zhu, Xudong; Mander, Lewis N.; Kamiya, Yuji; Yamaguchi, Shinjiro; He, Zuhua

    2006-01-01

    The recessive tall rice (Oryza sativa) mutant elongated uppermost internode (eui) is morphologically normal until its final internode elongates drastically at the heading stage. The stage-specific developmental effect of the eui mutation has been used in the breeding of hybrid rice to improve the performance of heading in male sterile cultivars. We found that the eui mutant accumulated exceptionally large amounts of biologically active gibberellins (GAs) in the uppermost internode. Map-based cloning revealed that the Eui gene encodes a previously uncharacterized cytochrome P450 monooxygenase, CYP714D1. Using heterologous expression in yeast, we found that EUI catalyzed 16α,17-epoxidation of non-13-hydroxylated GAs. Consistent with the tall and dwarfed phenotypes of the eui mutant and Eui-overexpressing transgenic plants, respectively, 16α,17-epoxidation reduced the biological activity of GA4 in rice, demonstrating that EUI functions as a GA-deactivating enzyme. Expression of Eui appeared tightly regulated during plant development, in agreement with the stage-specific eui phenotypes. These results indicate the existence of an unrecognized pathway for GA deactivation by EUI during the growth of wild-type internodes. The identification of Eui as a GA catabolism gene provides additional evidence that the GA metabolism pathway is a useful target for increasing the agronomic value of crops. PMID:16399803

  19. A simple shoot multiplication procedure using internode explants, and its application for particle bombardment and Agrobacterium-mediated transformation in watercress.

    PubMed

    Ogita, Shinjiro; Usui, Miki; Shibutani, Nanae; Kato, Yasuo

    2009-07-01

    A shoot multiplication system derived from internode explants was investigated with the aim of improving genetic characteristics of watercress (Nasturtium officinale R. Br.). Internodes of ca. 1 cm excised from in vitro stock shoot culture were placed on half-strength Murashige and Skoog (MS) medium supplemented with 3 muM 2,4-dichlorophenoxyacetic acid as a pre-treatment. Laser scanning microscopy indicated clearly that the first sign of meristematic cell division could be seen after 1-2 days of pre-culture, and meristematic tissues multiplied along the vascular cambium of the internode segment during 7 days of culture. Multiple shoots could be obtained from more than 90% of the pre-treated explants when they were subsequently transferred to MS medium supplemented with 1 muM thidiazuron for 3 weeks. These findings indicate that pre-treatment of the internodes for 7 days promoted their capacity for organogenesis. Using this pre-treatment, frequent generation of transgenic watercress plants was achieved by adapting particle bombardment and Agrobacterium-mediated transformation techniques with a construct expressing a synthetic green florescent protein gene.

  20. Photosynthesis-dependent formation of convoluted plasma membrane domains in Chara internodal cells is independent of chloroplast position.

    PubMed

    Foissner, Ilse; Sommer, Aniela; Hoeftberger, Margit

    2015-07-01

    The characean green alga Chara australis forms complex plasma membrane convolutions called charasomes when exposed to light. Charasomes are involved in local acidification of the surrounding medium which facilitates carbon uptake required for photosynthesis. They have hitherto been only described in the internodal cells and in close contact with the stationary chloroplasts. Here, we show that charasomes are not only present in the internodal cells of the main axis, side branches, and branchlets but that the plasma membranes of chloroplast-containing nodal cells, protonemata, and rhizoids are also able to invaginate into complex domains. Removal of chloroplasts by local irradiation with intense light revealed that charasomes can develop at chloroplast-free "windows" and that the resulting pH banding pattern is independent of chloroplast or window position. Charasomes were not detected along cell walls containing functional plasmodesmata. However, charasomes formed next to a smooth wound wall which was deposited onto the plasmodesmata-containing wall when the neighboring cell was damaged. In contrast, charasomes were rarely found at uneven, bulged wound walls which protrude into the streaming endoplasm and which were induced by ligation or puncturing. The results of this study show that charasome formation, although dependent on photosynthesis, does not require intimate contact with chloroplasts. Our data suggest further that the presence of plasmodesmata inhibits charasome formation and/or that exposure to the outer medium is a prerequisite for charasome formation. Finally, we hypothesize that the absence of charasomes at bulged wound walls is due to the disturbance of uniform laminar mass streaming.

  1. Relationships of the internodal distance of biological tissue with its sound velocity and attenuation at high frequency in doublet mechanics

    NASA Astrophysics Data System (ADS)

    Cheng, Kai-Xuan; Wu, Rong-Rong; Liu, Xiao-Zhou; Liu, Jie-Hui; Gong, Xiu-Fen; Wu, Jun-Ru

    2015-04-01

    In view of the discrete characteristics of biological tissue, doublet mechanics has demonstrated its advantages in the mathematic description of tissue in terms of high frequency (> 10 MHz) ultrasound. In this paper, we take human breast biopsies as an example to study the influence of the internodal distance, a microscope parameter in biological tissue in doublet mechanics, on the sound velocity and attenuation by numerical simulation. The internodal distance causes the sound velocity and attenuation in biological tissue to change with the increase of frequency. The magnitude of such a change in pathological tissue is distinctly different from that in normal tissue, which can be used to differentiate pathological tissue from normal tissue and can depict the diseased tissue structure by obtaining the sound and attenuation distribution in the sample at high ultrasound frequency. A comparison of sensitivity between the doublet model and conventional continuum model is made, indicating that this is a new method of characterizing ultrasound tissue and diagnosing diseases. Project supported by the National Basic Research Program of China (Grant Nos. 2012CB921504 and 2011CB707902), the National Natural Science Foundation of China (Grant No. 11274166), the Fundamental Research Funds for the Central Universities, China (Grant Nos. 1113020403 and 1101020402), the State Key Laboratory of Acoustics, Chinese Academy of Sciences (Grant No. SKLA201401), the China Postdoctoral Science Foundation (Grant No. 2013M531313), the Priority Academic Program Development of Jiangsu Provincial Higher Education Institutions and Scientific Research Foundation for Returned Overseas Chinese Scholars, State Education Ministry, and the Project of Interdisciplinary Center of Nanjing University, China (Grant No. NJUDC2012004).

  2. Overcoming deep roots, fast rates, and short internodes to resolve the ancient rapid radiation of eupolypod II ferns.

    PubMed

    Rothfels, Carl J; Larsson, Anders; Kuo, Li-Yaung; Korall, Petra; Chiou, Wen-Liang; Pryer, Kathleen M

    2012-05-01

    Backbone relationships within the large eupolypod II clade, which includes nearly a third of extant fern species, have resisted elucidation by both molecular and morphological data. Earlier studies suggest that much of the phylogenetic intractability of this group is due to three factors: (i) a long root that reduces apparent levels of support in the ingroup; (ii) long ingroup branches subtended by a series of very short backbone internodes (the "ancient rapid radiation" model); and (iii) significantly heterogeneous lineage-specific rates of substitution. To resolve the eupolypod II phylogeny, with a particular emphasis on the backbone internodes, we assembled a data set of five plastid loci (atpA, atpB, matK, rbcL, and trnG-R) from a sample of 81 accessions selected to capture the deepest divergences in the clade. We then evaluated our phylogenetic hypothesis against potential confounding factors, including those induced by rooting, ancient rapid radiation, rate heterogeneity, and the Bayesian star-tree paradox artifact. While the strong support we inferred for the backbone relationships proved robust to these potential problems, their investigation revealed unexpected model-mediated impacts of outgroup composition, divergent effects of methods for countering the star-tree paradox artifact, and gave no support to concerns about the applicability of the unrooted model to data sets with heterogeneous lineage-specific rates of substitution. This study is among few to investigate these factors with empirical data, and the first to compare the performance of the two primary methods for overcoming the Bayesian star-tree paradox artifact. Among the significant phylogenetic results is the near-complete support along the eupolypod II backbone, the demonstrated paraphyly of Woodsiaceae as currently circumscribed, and the well-supported placement of the enigmatic genera Homalosorus, Diplaziopsis, and Woodsia.

  3. Tomato SlDREB gene restricts leaf expansion and internode elongation by downregulating key genes for gibberellin biosynthesis

    PubMed Central

    Ye, Zhibiao

    2012-01-01

    Plants have evolved and adapted to different environments. Dwarfism is an adaptive trait of plants that helps them avoid high-energy costs under unfavourable conditions. The role of gibberellin (GA) in plant development has been well established. Several plant dehydration-responsive element-binding proteins (DREBs) have been identified and reported to be induced under abiotic and biotic stress conditions. A tomato DREB gene named SlDREB, which is a transcription factor and was cloned from cultivated tomato M82, was found to play a negative role in tomato plant architecture and enhances drought tolerance. Tissue expression profiles indicated that SlDREB was expressed mainly in the stem and leaf and could be induced by abscisic acid (ABA) but suppressed by GA and ethylene. SlDREB altered plant morphology by restricting leaf expansion and internode elongation when overexpressed, and the resulting dwarfism of tomato plants could be recovered by application of exogenous gibberellic acid (GA3). Transcriptional analysis of transgenic plants revealed that overexpression of SlDREB caused the dwarf phenotype by downregulating key genes involved in GA biosynthesis such as ent-copalyl diphosphate synthase (SlCPS) and GA 20-oxidases (SlGA20ox1, -2, and -4), thereby decreasing endogenous GA levels in transgenic plants. A yeast activity assay demonstrated that SlDREB specifically bound to dehydration-responsive element/C-repeat (DRE/CRT) elements of the SlCPS promoter region. Taken together, these data demonstrated that SlDREB can downregulate the expression of key genes required for GA biosynthesis and that it acts as a positive regulator in drought stress responses by restricting leaf expansion and internode elongation. PMID:23077200

  4. Tomato SlDREB gene restricts leaf expansion and internode elongation by downregulating key genes for gibberellin biosynthesis.

    PubMed

    Li, Jinhua; Sima, Wei; Ouyang, Bo; Wang, Taotao; Ziaf, Khurram; Luo, Zhidan; Liu, Lifeng; Li, Hanxia; Chen, Mingluan; Huang, Yunqing; Feng, Yuqi; Hao, Yanhong; Ye, Zhibiao

    2012-11-01

    Plants have evolved and adapted to different environments. Dwarfism is an adaptive trait of plants that helps them avoid high-energy costs under unfavourable conditions. The role of gibberellin (GA) in plant development has been well established. Several plant dehydration-responsive element-binding proteins (DREBs) have been identified and reported to be induced under abiotic and biotic stress conditions. A tomato DREB gene named SlDREB, which is a transcription factor and was cloned from cultivated tomato M82, was found to play a negative role in tomato plant architecture and enhances drought tolerance. Tissue expression profiles indicated that SlDREB was expressed mainly in the stem and leaf and could be induced by abscisic acid (ABA) but suppressed by GA and ethylene. SlDREB altered plant morphology by restricting leaf expansion and internode elongation when overexpressed, and the resulting dwarfism of tomato plants could be recovered by application of exogenous gibberellic acid (GA(3)). Transcriptional analysis of transgenic plants revealed that overexpression of SlDREB caused the dwarf phenotype by downregulating key genes involved in GA biosynthesis such as ent-copalyl diphosphate synthase (SlCPS) and GA 20-oxidases (SlGA20ox1, -2, and -4), thereby decreasing endogenous GA levels in transgenic plants. A yeast activity assay demonstrated that SlDREB specifically bound to dehydration-responsive element/C-repeat (DRE/CRT) elements of the SlCPS promoter region. Taken together, these data demonstrated that SlDREB can downregulate the expression of key genes required for GA biosynthesis and that it acts as a positive regulator in drought stress responses by restricting leaf expansion and internode elongation.

  5. Water use sources of desert riparian Populus euphratica forests.

    PubMed

    Si, Jianhua; Feng, Qi; Cao, Shengkui; Yu, Tengfei; Zhao, Chunyan

    2014-09-01

    Desert riparian forests are the main body of natural oases in the lower reaches of inland rivers; its growth and distribution are closely related to water use sources. However, how does the desert riparian forest obtains a stable water source and which water sources it uses to effectively avoid or overcome water stress to survive? This paper describes an analysis of the water sources, using the stable oxygen isotope technique and the linear mixed model of the isotopic values and of desert riparian Populus euphratica forests growing at sites with different groundwater depths and conditions. The results showed that the main water source of Populus euphratica changes from water in a single soil layer or groundwater to deep subsoil water and groundwater as the depth of groundwater increases. This appears to be an adaptive selection to arid and water-deficient conditions and is a primary reason for the long-term survival of P. euphratica in the desert riparian forest of an extremely arid region. Water contributions from the various soil layers and from groundwater differed and the desert riparian P. euphratica forests in different habitats had dissimilar water use strategies.

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

    PubMed

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

    2010-04-01

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

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

    SciTech Connect

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

    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.

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

    PubMed

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

    2012-11-01

    Shade avoidance signaling involves perception of incident red/far-red (R/FR) light by phytochromes (PHYs) and modulation of downstream transcriptional networks. Although these responses are well studied in Arabidopsis, little is known about the role of PHYs and the transcriptional responses to shade in the woody perennial Populus. Tissue expression and subcellular localization of Populus PHYs was studied by quantitative real-time PCR (qRT-PCR) and protoplast transient assay. Transgenic lines with altered PHYB1 and/or PHYB2 expression were used in phenotypic assays and transcript profiling with qRT-PCR. RNA-Seq was used to identify transcriptional responses to enriched FR light. All three PHYs were differentially expressed among tissue types and PHYBs were targeted to the nucleus under white light. Populus PHYB1 rescued Arabidopsis phyB mutant phenotypes. Phenotypes of Populus transgenic lines and the expression of candidate shade response genes suggested that PHYB1 and PHYB2 have distinct yet overlapping functions. RNA-Seq analysis indicated that genes associated with cell wall modification and brassinosteroid signaling were induced under enriched FR light in Populus. This study is an initial attempt at deciphering the role of Populus PHYs by evaluating transcriptional reprogramming to enriched FR and demonstrates functional diversity and overlap of the Populus PHYB1 and PHYB2 in regulating shade responses.

  9. Genome Analyses and Supplement Data from the International Populus Genome Consortium (IPGC)

    DOE Data Explorer

    International Populus Genome Consortium (IPGC)

    The sequencing of the first tree genome, that of Populus, was a project initiated by the Office of Biological and Environmental Research in DOE’s Office of Science. The International Populus Genome Consortium (IPGC) was formed to help develop and guide post-sequence activities. The IPGC website, hosted at the Oak Ridge National Laboratory, provides draft sequence data as it is made available from DOE Joint Genome Institute, genome analyses for Populus, lists of related publications and resources, and the science plan. The data are available at http://www.ornl.gov/sci/ipgc/ssr_resource.htm.

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

    PubMed

    Nishiguchi, Mitsuru; Nanjo, Tokihiko; Yoshida, Kazumasa

    2012-07-01

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

  11. Using low energy x-ray radiography to evaluate root initiation and growth of Populus

    Treesearch

    Ronald S., Jr. Zalesny; A. L. Friend; B. Kodrzycki; D.W. McDonald; R. Michaels; A.H. Wiese; J.W. Powers

    2007-01-01

    Populus roots have been studied less than aboveground tissues. However, there is an overwhelming need to evaluate root initiation and growth in order to understand the genetics and physiology of rooting, along with genotype x environment interactions.

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

    PubMed

    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.

  13. Nanometrology of delignified Populus using mode synthesizing atomic force microscopy

    SciTech Connect

    Tetard, Laurene; Passian, Ali; Farahi, R H; Davison, Brian H; Jung, S; Ragauskas, A J; Lereu, Aude; Thundat, Thomas George

    2011-01-01

    The study of the spatially resolved physical and compositional properties of materials at the nanoscale is increasingly challenging due to the level of complexity of biological specimens such as those of interest in bioenergy production. Mode synthesizing atomic force microscopy (MSAFM) has emerged as a promising metrology tool for such studies. It is shown that, by tuning the mechanical excitation of the probe-sample system, MSAFM can be used to dynamically investigate the multifaceted complexity of plant cells. The results are argued to be of importance both for the characteristics of the invoked synthesized modes and for accessing new features of the samples. As a specific system to investigate, we present images of Populus, before and after a holopulping treatment, a crucial step in the biomass delignification process.

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

    PubMed Central

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

    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 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. PMID:24803501

  15. A developing Setaria viridis internode: an experimental system for the study of biomass generation in a C4 model species.

    PubMed

    Martin, Antony P; Palmer, William M; Brown, Christopher; Abel, Christin; Lunn, John E; Furbank, Robert T; Grof, Christopher P L

    2016-01-01

    Recently, there has been interest in establishing a monocot C4 model species with a small genome, short lifecycle, and capacity for genetic transformation. Setaria viridis has been adopted to fill this role, since reports of Agrobacterium-mediated transformation in 2010, and sequencing of its genome in 2012. To date, S. viridis has primarily been used to further our understanding of C4 photosynthesis, but is also an ideal system for the study of biomass crops, which are almost exclusively C4 panicoid grasses. Biogenesis of stem tissue, its cell wall composition, and soluble sugar content are important determinants of bioenergy crop yields. Here we show that a developing S. viridis internode is a valuable experimental system for gene discovery in relation to these important bioenergy feedstock traits. The rate of maximal stem biomass accumulation in S. viridis A10 under long day growth was at the half-head emergence developmental stage. At this stage of development, internode 5 (of 7) was found to be rapidly expanding with an active meristem, a zone of cell expansion (primary cell walls), a transitional zone where cell expansion ceased and secondary cell wall deposition was initiated, and a mature zone that was actively accumulating soluble sugars. A simple method for identifying these zones was established allowing rapid dissection and snap-freezing for RNAseq analysis. A transcriptome profile was generated for each zone showing a transition from cell division and nucleic acid synthesis/processing in the meristem, to metabolism, energy synthesis, and primary cell wall synthesis in the cell expansion zone, to secondary cell wall synthesis in the transitional zone, to sugar transport, and photosynthesis in the mature zone. The identification of these zones has provided a valuable experimental system for investigating key bioenergy traits, including meristematic activity, cell wall biosynthesis, and soluble sugar accumulation, in a C4 panicoid grass that has genetic

  16. Highly efficient CRISPR/Cas9-mediated targeted mutagenesis of multiple genes in Populus.

    PubMed

    Tingting, Liu; Di, Fan; Lingyu, Ran; Yuanzhong, Jiang; Rui, Liu; Keming, Luo

    2015-10-01

    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 technique. 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 single-guide RNA (sgRNA) that target PDS DNA sequence. We found that mismatches between the sgRNA and the target DNA resulted in decreased efficiency of mutagenesis and even failed mutagenesis. Moreover, complementarity 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 simultaneously 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.

  17. Association Genetics of Populus trichocarpa or Resequencing in Populus: Towards Genome Wide Association Genetics (2011 JGI User Meeting)

    ScienceCinema

    Tuskan, Gerry

    2016-07-12

    The U.S. Department of Energy Joint Genome Institute (JGI) invited scientists interested in the application of genomics to bioenergy and environmental issues, as well as all current and prospective users and collaborators, to attend the annual DOE JGI Genomics of Energy & Environment Meeting held March 22-24, 2011 in Walnut Creek, Calif. The emphasis of this meeting was on the genomics of renewable energy strategies, carbon cycling, environmental gene discovery, and engineering of fuel-producing organisms. The meeting features presentations by leading scientists advancing these topics. Gerry Tuskan of Oak Ridge National Laboratory on "Resequencing in Populus: Towards Genome Wide Association Genetics" at the 6th annual Genomics of Energy & Environment Meeting on March 23, 2011

  18. Organogenesis from internode-derived nodules of Humulus lupulus var. Nugget (Cannabinaceae): histological studies and changes in the starch content.

    PubMed

    Fortes, A M; Pais, M S

    2000-07-01

    The sequence of histological and histochemical events occurring during organogenesis from Humulus lupulus var. Nugget internode-derived nodules was studied. Sections were made and studies were carried out from the start of culture treatment until the development of shoot buds. Cell division was observed in both cambial and cortical regions during the first week of culture establishment. Cell division in cortical cells led to the formation of an incipient callus tissue. From the calluses prenodular structures of cambial origin appeared and gave rise to nodules from which shoot buds formed. Nodules kept separating into "daughter nodules" from which arose an increasing number of shoot buds. Iodide staining showed a strong starch accumulation in callus tissue and in prenodular structures. During shoot-bud primordia formation starch content decreased in nodules. Some starch was also noted in control explants (cultured on basal medium), however at a lower level than that observed in explants cultured on media with growth regulators. Shoot-bud regeneration was not observed in control explants.

  19. Differential expression and cellular localization of ERKs during organogenic nodule formation from internodes of Humulus lupulus var. Nugget.

    PubMed

    Sousa Silva, Marta; Margarida Fortes, Ana; Sanchéz Testillanob, Pilar; Risueño, Maria del Carmen; Salom'e Pais, Maria

    2004-08-01

    The expression and subcellular localization of extracellular signal-regulated kinase 1 or 2 (ERK1/2) homologues (HLERK1/2) during the process of organogenic nodule formation in Humulus lupulus var. Nugget was studied using antibodies specific for ERK1 and ERK2, and for phosphorylated mitogen-activated protein kinases (MAPKs). The increase in HLERK levels, detected by Western blotting 12 hours after wounding suggests their involvement in response to the wounding treatment applied for morphogenesis induction. In dividing cambial cells, occurring in between 4 and 7 days after morphogenesis induction, as well as in dividing prenodular cells (15 days after induction) HLERK1 and/or 2 were localized in the nucleus. However, as soon as nodular cells start proliferating to form shoot meristems, HLERK1 and 2 were detected in the cytoplasm and not in the nucleus. The data reported account for a differential expression and activation of HLERK1 and HLERK2 throughout the process of nodule formation and plantlet regeneration. HLERK1 appears to be expressed in the stages of nodule formation and plantlet regeneration, playing a possible role in controlling cell proliferation and differentiation. HLERK2 may be induced as a response to reactive oxygen species (ROS) generated by wounding of internodes as its expression is reduced in liquid medium with less oxygen availability compared to solid medium. However, addition of a ROS inhibitor to the liquid medium does not result in a further decrease in the HLERK2 level.

  20. Characterization of internodal collecting lymphatic vessel function after surgical removal of an axillary lymph node in mice

    PubMed Central

    Kwon, Sunkuk; Price, Roger E.

    2016-01-01

    Secondary lymphedema is an acquired lymphatic disorder, which occurs because of damage to the lymphatic system from surgery and/or radiation therapy for cancer treatment. However, it remains unknown how post-nodal collecting lymphatic vessels (CLVs) draining to the surgical wound area change in response to lymphadenectomy. We investigated functional and architectural changes of inguinal-to-axillary internodal CLVs (ICLVs) in mice after a single axillary LN (ALN) dissection using near-infrared fluorescence imaging. Our data showed no lymph flow in the ICLVs draining from the inguinal LN (ILN) at 2 days post-surgery. External compression enabled visualization of a small segment of contractile fluorescent ICLVs, but not all the way to the axillary region. At day 6, abnormal lymphatic drainage patterns, including lateral and retrograde lymph flow via vessels branching off the ICLVs were observed, which started to disappear beginning 9 days after surgery. The administration of vascular endothelial growth factor (VEGF)-C into the wound increased resolution of altered lymphatic drainage. Lymphatic drainage from the base of the tail to the ILN did not significantly change over time. These results demonstrate that lymph flow in the CLVs is dramatically affected by a LN dissection and long-term interruption of lymph flow might cause CLV dysfunction and thus contribute to chronic lymphatic disorders. PMID:27446639

  1. Diurnal regulation of plastid genes in Populus deltoides.

    PubMed

    Reddy, M S; Naithani, S; Tuli, R; Sane, P V

    2000-12-01

    Light regulates leaf and chloroplast development, together with overall chloroplast gene expression at various levels. Plants respond to diurnal and seasonal changes in light by changing expression of photosynthesis genes and metabolism. In Populus deltoides, a deciduous tree species, leaf development begins in the month of March and leaf maturation is attained by summer, which is subsequently followed by autumnal senescence and fall. In the present study, diurnal changes in the steady state transcript levels of plastid genes were examined in the fully developed leaves during summer season. Our results show that steady state level of the psaA/B, psbA, psbEFLJ and petA transcripts showed differential accumulation during diurnal cycle in summer. However, there was no significant change in the pigment composition during the day/night cycle. Our studies suggest that the diurnal regulation of steady state mRNA accumulation may play a crucial role during daily adjustments in plants life with rapidly changing light irradiance and temperature.

  2. Nesterenkonia populi sp. nov., an actinobacterium isolated from Populus euphratica.

    PubMed

    Liu, Jia-Meng; Tuo, Li; Habden, Xugela; Guo, Lin; Jiang, Zhong-Ke; Liu, Xian-Fu; Chen, Li; Zhang, Yu-Qin; Sun, Cheng-Hang

    2015-05-01

    An alkaliphilic and moderately halophilic actinobacterium, designated strain GP10-3(T), was isolated from Populus euphratica collected from the southern edge of Taklimakan desert, Xinjiang, China. Cells of this strain were Gram-stain-positive, non-motile and non-spore-forming short rods. Strain GP10-3(T) grew optimally at 37 °C on LB agar media in the presence of 5-10% (w/v) NaCl at pH 9.0. The menaquinones were MK-7, MK-8 and MK-9. The major fatty acids (>10%) were anteiso-C17 : 0, anteiso-C15 : 0 and iso-C16 : 0. The peptidoglycan type was variation A4α, L-Lys-L-Glu. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylglycolipid, phosphatidylcholine, phosphatidylinositol, glycolipid and an unidentified phospholipid. The DNA G+C content was 67.4 mol%. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain GP10-3(T) belonged to the genus Nesterenkonia , sharing 94.6-96.9% sequence similarity with the type strains of species within this genus with validly published names. Based on the evidence of the polyphasic taxonomic study, strain GP10-3(T) represents a novel species of the genus Nesterenkonia , for which the name Nesterenkonia populi sp. nov. is proposed. The type strain is GP10-3(T) ( = DSM 27959(T) = KCTC 29119(T)).

  3. Spatiotemporal distribution of essential elements through Populus leaf ontogeny

    PubMed Central

    Carvalho, Mónica R.; Woll, Arthur; Niklas, Karl J.

    2016-01-01

    We examined the spatiotemporal distribution and accumulation of calcium (Ca), potassium (K), and zinc (Zn) during the growth and maturation of grey poplar (Populus tremula × alba) leaves covering plastochrons 01 through 10. This period spans the sugar sink-to-source transition and requires coordinated changes of multiple core metabolic processes that likely involve alterations in essential and non-essential element distributions as tissues mature and effect a reversal in phloem flow direction. Whole-leaf elemental maps were obtained from dried specimens using micro X-ray fluorescence spectroscopy. Additional cross-sections of fresh leaves were scanned to check for tissue specificity in element accumulation. The anatomical distribution of Zn and K remains relatively consistent throughout leaf development; Ca accumulation varied across leaf developmental stages. The basipetal allocation of Ca to the leaf mesophyll matched spatially and temporally the sequence of phloem maturation, positive carbon balance, and sugar export from leaves. The accumulation of Ca likely reflects the maturation of xylem in minor veins and the enhancement of the transpiration stream. Our results independently confirm that xylem and phloem maturation are spatially and temporally coordinated with the onset of sugar export in leaves. PMID:26985054

  4. Rhizobacteria of Populus euphratica Promoting Plant Growth Against Heavy Metals.

    PubMed

    Zhu, Donglin; Ouyang, Liming; Xu, Zhaohui; Zhang, Lili

    2015-01-01

    The heavy metal-resistant bacteria from rhizospheric soils of wild Populus euphratica forest growing in arid and saline area of northwestern China were investigated by cultivation-dependent methods. After screening on medium sparked with zinc, copper, nickel and lead, 146 bacteria strains with different morphology were isolated and most of them were found to be resistant to at least two kinds of heavy metals. Significant increase in fresh weight and leaf surface area of Arabidopsis thaliana seedlings under metal stress were noticed after inoculated with strains especially those having multiple-resistance to heavy metals such as Phyllobacterium sp. strain C65. Investigation on relationship between auxin production and exogenous zinc concentration revealed that Phyllobacterium sp. strain C65 produced auxin, and production decreased as the concentration of zinc in medium increased. For wheat seedlings treated with zinc of 2 mM, zinc contents in roots of inoculated plants decreased by 27% (P < 0.05) compared to the uninoculated control. Meanwhile, zinc accumulation in the above-ground tissues increased by 22% (P < 0.05). The translocation of zinc from root to above-ground tissues induced by Phyllobacterium sp. strain C65 helped host plants extract zinc from contaminated environments more efficiently thus alleviated the growth inhibition caused by heavy metals.

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

    PubMed

    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

  6. Adaptive evolution and functional innovation of Populus-specific recently evolved microRNAs.

    PubMed

    Xie, Jianbo; Yang, Xiaohui; Song, Yuepeng; Du, Qingzhang; Li, Ying; Chen, Jinhui; Zhang, Deqiang

    2017-01-01

    Lineage-specific microRNAs (miRNAs) undergo rapid turnover during evolution; however, their origin and functional importance have remained controversial. Here, we examine the origin, evolution, and potential roles in local adaptation of Populus-specific miRNAs, which originated after the recent salicoid-specific, whole-genome duplication. RNA sequencing was used to generate extensive, comparable miRNA and gene expression data for six tissues. A natural population of Populus trichocarpa and closely related species were used to study the divergence rates, evolution, and adaptive variation of miRNAs. MiRNAs that originated in 5' untranslated regions had higher expression levels and their expression showed high correlation with their host genes. Compared with conserved miRNAs, a significantly higher proportion of Populus-specific miRNAs appear to target genes that were duplicated in salicoids. Examination of single nucleotide polymorphisms in Populus-specific miRNA precursors showed high amounts of population differentiation. We also characterized the newly emerged MIR6445 family, which could trigger the production of phased small interfering RNAs from NAC mRNAs, which encode a transcription factor with primary roles in a variety of plant developmental processes. Together, these observations provide evolutionary insights into the birth and potential roles of Populus-specific miRNAs in genome maintenance, local adaptation, and functional innovation.

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

    PubMed

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

    2009-01-01

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

  8. A survey of Populus PIN-FORMED family genes reveals their diversified expression patterns.

    PubMed

    Liu, Bobin; Zhang, Jin; Wang, Lin; Li, Jianbo; Zheng, Huanquan; Chen, Jun; Lu, Mengzhu

    2014-06-01

    The plant hormone auxin is a key regulator of plant development, and its uneven distribution maintained by polar intercellular auxin transport in plant tissues can trigger a wide range of developmental processes. Although the roles of PIN-FORMED (PIN) proteins in intercellular auxin flow have been extensively characterized in Arabidopsis, their roles in woody plants remain unclear. Here, a comprehensive analysis of PIN proteins in Populus is presented. Fifteen PINs are encoded in the genome of Populus, including four PIN1s, one PIN2, two PIN3s, three PIN5s, three PIN6s, and two PIN8s. Similar to Arabidopsis AtPIN proteins, PtPINs share conserved topology and transmembrane domains, and are either plasma membrane- or endoplasmic reticulum-localized. The more diversified expansion of the PIN family in Populus, comparing to that in Arabidopsis, indicates that some auxin-regulated developmental processes, such as secondary growth, may exhibit unique features in trees. More importantly, different sets of PtoPINs have been found to be strongly expressed in the roots, leaves, and cambium in Populus; the dynamic expression patterns of selected PtoPINs were further examined during the regeneration of shoots and roots. This genome-wide analysis of the Populus PIN family provides important cues for their potential roles in tree growth and development.

  9. Effects of Clone, Silvicultural, and Miticide Treatments on Cottonwood Leafcurl Mite (Acari: Eriophyidae) Damage in Plantation Populus

    Treesearch

    David R. Coyle

    2002-01-01

    Aculops lobuliferus (Keifer) is a little known pest of plantation Populus spp., which is capable of causing substantial damage. This is the First documented occurrence of A. lobuliferus in South Carolina. Previous anecdotal data indicated clonal variation in Populus susceptibility to A...

  10. Clonal variation in morphology of Populus root systems following irrigation with landfill leachate or water during 2 years of establishment

    Treesearch

    Jill A. Zalesny; Ronald S., Jr. Zalesny; David R. Coyle; Richard B. Hall; Edmund O. Bauer

    2009-01-01

    Increased municipal solid waste generation in North America has prompted the use of Populus for phytoremediation of waste waters including landfill leachate. Populus species and hybrids are ideal for such applications because of their high water usage rates, fast growth, and extensive root systems. Adventitious rooting (i.e.,...

  11. Uptake of macro- and micro-nutrients into leaf, woody, and root tissue of Populus after irrigation with landfill leachate

    Treesearch

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

    2008-01-01

    Information about macro- and micro-nutrient uptake and distribution into tissues of Populus irrigated with landfill leachate helps to maximize biomass production and understand impacts of leachate chemistry on tree health. We irrigated eight Populus clones (NC 13460, NCI4O18, NC14104, NC14106, DM115, DN5, NM2, NM6) with fertilized (N, P, K) well...

  12. Phytoaccumulation of sodium and chloride into leaf, woody, and root tissue of Populus irrigated with landfill leachate

    Treesearch

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

    2007-01-01

    Information is limited about the response of Populus to elevated levels of sodium (Na+) and chloride (Cl-). We irrigated eight Populus clones (NC13460, NC14018, NC14104, NC14106, DM115, DN5, NM2, NM6) with fertilized well water (control) (N, P, K) or municipal solid waste landfill leachate weekly during...

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

    Treesearch

    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...

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

    Treesearch

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

    Treesearch

    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.

  16. Mathematical modeling of RDX and HMX metabolism in poplar (Populus deltoides x Populus nigra, DN34) tissue culture.

    PubMed

    Mezzari, Melissa P; Van Aken, Benoit; Yoon, Jong M; Just, Craig L; Schnoor, Jerald L

    2004-01-01

    Three mathematical models were developed based on a fate study as an approach to define transformation pathways of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) within plant cells. [U-14C]RDX and [U-14C]HMX were added in Murashige and Skoog (MS) liquid media containing Populus deltoides x P. nigra (DN34) tissue cultures. Radioactivity of samples was analyzed using HPLC, a bio-oxidizer and liquid scintillation counter. Based on information collected, transformation pathways of nitramine compounds were fitted with the raw data obtained and using a modified "green liver" model. Ordinary differential equations were developed and simulations were performed with MicroMath Scientist version 2.0 (MicroMath Inc., St. Louis, MO, USA). The three models, with different sequential transformation processes, were tested in order to support the raw data (model I) and the assumptions of the modified "green liver" model (models II and III). The results showed a high correlation between the collected data and the simulated concentrations for all models. Thus, the simplest model developed (model I) is the best model description of these particular results. The results obtained suggest that the principle of parsimony should be applied. The "green liver"-based models also demonstrated a reliable approach for the investigation of degradation pathways of nitramines within plant cells.

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

    SciTech Connect

    Kalluri, Udaya C; DiFazio, Stephen P; Brunner, A.; Tuskan, Gerald A

    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.

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

    SciTech Connect

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

    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.

  19. Analysis on active molecules in Populus nigra wood extractives by GC-MS.

    PubMed

    Li, Dongli; Peng, Wanxi; Ge, Shengbo; Mo, Bo; Zhang, Zhongfeng; Qin, Daochun

    2014-11-01

    Populus nigra has been introduced and largely planted in China, and the waste wood was still abandoned. Therefore, the wood extractives of Populus nigra were studied to further utilize the bio-resources. The result shown that the optimal extraction time of ethanol/methanol extraction, petroleum ether/acetic ether extraction, and benzene/alcohol extraction were 1h, 7h and 3h, respectively. Among sequential extractions, EPB extraction was the optimum extraction mode for the LR was 17.32%. The wood extractives included hexanedioic acid, bis(2-ethylhexyl) ester, phthalic acid derivatives, squalene, 3,3,7,11- tetramethyltricyclo [5.4.0.0(4,11)]undecan-1-ol, other rare drug and biomedical activities. The wood extractives of Populus nigra was fit to extract rare dibutyl phthalate and squalene.

  20. Patterns of molecular evolution and predicted function in thaumatin-like proteins of Populus trichocarpa.

    PubMed

    Zhao, Jia Ping; Su, Xiao Hua

    2010-09-01

    Some pathogenesis-related proteins (PR proteins) are subject to positive selection, while others are under negative selection. Here, we report the patterns of molecular evolution in thaumatin-like protein (TLP, PR5 protein) genes of Populus trichocarpa. Signs of positive selection were found in 20 out of 55 Populus TLPs using the likelihood ratio test and ML-based Bayesian methods. Due to the connection between the acidic cleft and the antifungal activity, the secondary structure and three-dimensional structure analyses predicted antifungal activity beta-1,3-glucanase activities in these TLPs. Moreover, the coincidence with variable basic sites in the acidic cleft and positively selected sites suggested that fungal diseases may have been the main environmental stress that drove rapid adaptive evolution in Populus.

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

    PubMed

    Kersten, Birgit; Faivre Rampant, Patricia; Mader, Malte; Le Paslier, Marie-Christine; Bounon, Rémi; Berard, Aurélie; Vettori, Cristina; Schroeder, Hilke; Leplé, Jean-Charles; Fladung, Matthias

    2016-01-01

    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.

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

    PubMed Central

    Mader, Malte; Le Paslier, Marie-Christine; Bounon, Rémi; Berard, Aurélie; Vettori, Cristina; Schroeder, Hilke; Leplé, Jean-Charles; Fladung, Matthias

    2016-01-01

    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. PMID:26800039

  3. Establishment of Populus deltoides under simulated alluvial groundwater declines

    USGS Publications Warehouse

    Segelquist, Charles A.; Scott, Michael L.; Auble, Gregor T.

    1993-01-01

    Establishment, growth, and survival of seedlings of Populus deltoides subsp. monilifera (plains cottonwood) were examined in an experimental facility simulating five rates of declining alluvial groundwater. The treatments were permanent saturation, drawdown rates of 0.4, 0.7, 2.9 cm/d and immediate drainage. The experiment was conducted outdoors in planters near Fort Collins, Colorado. Seedling survival was highest under the two slowest drawdown rates and declined significantly with faster drawdown rates. The highest growth rate was associated with the drawdown rate of 0.4 cm/d, in which mean shoot height was 2.4 cm and mean root length was 39 am 98 days after planting. Growth of shoots and roots was reduced both by saturated conditions and by the more rapid drawdown rates of 0.7 and 2.9 cm/d. No establishment was observed in the immediate drawdown treatment. Whereas maximum biomass accumulation is associated with the most gradual drawdown or saturated conditions, seedling establishing naturally under such conditions are also most likely to be removed by ice or subsequent flooding. Seedlings establishing in higher topographic positions, in contrast, are subject to increased mortality and reduced shoot growth, resulting from reduced soil moisture. Rapid root extension following establishment allows P. deltoides seedlings to grow across a wide range of groundwater drawdown rates, and thus a variety of positions across a gradient of riparian soil moisture. Our results indicate that in coarse alluvial sands of low fertility, 47% of germinating P. deltoides seeds were able to survive in associated with a drawdown rate of 2.9 cm/d and a final water table depth of 80 cm.

  4. Lignin content in natural Populus variants affects sugar release

    PubMed Central

    Studer, Michael H.; DeMartini, Jaclyn D.; Davis, Mark F.; Sykes, Robert W.; Davison, Brian; Keller, Martin; Tuskan, Gerald A.; Wyman, Charles E.

    2011-01-01

    The primary obstacle to producing renewable fuels from lignocellulosic biomass is a plant's recalcitrance to releasing sugars bound in the cell wall. From a sample set of wood cores representing 1,100 individual undomesticated Populus trichocarpa trees, 47 extreme phenotypes were selected across measured lignin content and ratio of syringyl and guaiacyl units (S/G ratio). This subset was tested for total sugar release through enzymatic hydrolysis alone as well as through combined hot-water pretreatment and enzymatic hydrolysis using a high-throughput screening method. The total amount of glucan and xylan released varied widely among samples, with total sugar yields of up to 92% of the theoretical maximum. A strong negative correlation between sugar release and lignin content was only found for pretreated samples with an S/G ratio < 2.0. For higher S/G ratios, sugar release was generally higher, and the negative influence of lignin was less pronounced. When examined separately, only glucose release was correlated with lignin content and S/G ratio in this manner, whereas xylose release depended on the S/G ratio alone. For enzymatic hydrolysis without pretreatment, sugar release increased significantly with decreasing lignin content below 20%, irrespective of the S/G ratio. Furthermore, certain samples featuring average lignin content and S/G ratios exhibited exceptional sugar release. These facts suggest that factors beyond lignin and S/G ratio influence recalcitrance to sugar release and point to a critical need for deeper understanding of cell-wall structure before plants can be rationally engineered for reduced recalcitrance and efficient biofuels production. PMID:21444820

  5. Stress-responsive microRNAs in Populus.

    PubMed

    Lu, Shanfa; Sun, Ying-Hsuan; Chiang, Vincent L

    2008-07-01

    MicroRNAs (miRNAs), a group of small non-coding RNAs, have recently become the subject of intense study. They are a class of post-transcriptional negative regulators playing vital roles in plant development and growth. However, little is known about their regulatory roles in the responses of trees to the stressful environments incurred over their long-term growth. Here, we report the cloning of small RNAs from abiotic stressed tissues of Populus trichocarpa (Ptc) and the identification of 68 putative miRNA sequences that can be classified into 27 families based on sequence homology. Among them, nine families are novel, increasing the number of the known Ptc-miRNA families from 33 to 42. A total of 346 targets was predicted for the cloned Ptc-miRNAs using penalty scores of

  6. Soil plant interactions of Populus alba in contrasting environments.

    PubMed

    Ciadamidaro, Lisa; Madejón, Engracia; Robinson, Brett; Madejón, Paula

    2014-01-01

    The effects of the Populus alba tree on different biochemical soil properties, growing in a contaminated area, were studied for two years under field conditions. Two types of trace element contaminated soils were studied: a neutral contaminated soil (NC) and an acid contaminated soil (AC). One neutral non-contaminated area was studied as control. Soil samples were collected at depths of 0-20 cm and 20-40 cm. Leaves and litter samples were analysed. The addition of organic matter, through root exudates and litter, contributed to an increase in soil pH, especially in acid soil. Microbial Biomass Carbon (MBC) was significantly increased by the presence of the trees in all studied areas, especially in the upper soil layer. Similar results were also observed for protease activity. Both MBC and Protease activity were more sensitive to contamination than β-glucosidase activity. These changes resulted in a decrease of available trace element concentrations in soil and in an improvement of soil quality after a 2-year study. The total concentration of Cd and Zn in soil did not increase over time due to litter deposition. Analysis of P. alba leaves did not show a significant nutritional imbalance and trace element concentrations were normal for plants, except for Cd and Zn. These results indicate that P. alba is suitable for the improvement of soil quality in riparian contaminated areas. However, due to the high Cd and Zn concentrations in leaves, further monitoring of this area is required.

  7. Examining Mechanisms of Methane Transport in Populus trichocarpa

    NASA Astrophysics Data System (ADS)

    Rosenstiel, T. N.; Kutschera, E.; Rice, A. L.; Kahlil, A.

    2016-12-01

    Although the dynamics of methane (CH4 ) emission from croplands and wetlands have been fairly well investigated, the contribution of trees to global CH4 emission and the mechanisms of tree transport are relatively unknown. CH4 emissions from the common wetland tree species Populus trichocarpa (black cottonwood) native to the Pacific Northwest were measured under hydroponic conditions in order to separate plant transport mechanisms from the influence of soil processes. Roots were exposed to CH4 enriched water and whole-canopy emissions of CH4 were measured. The average flux for 34 trials (at temperatures ranging from 17 to 25 C) was 2.8 ± 2.2 μg CH4 min-1(whole canopy). Overall intra-tree CH4 flux increased with temperature. Compared to the isotopic composition of root water CH4 , δ13 C values were depleted for canopy CH4 where the warmest temperatures (24.4-28.7 C) resulted in an epsilon of 2.8 ± 4.7‰; midrange temperatures (20.4- 22.1 C) produced an epsilon of 7.5 ±3.1 ‰; and the coolest temperatures examined (16.0-19.1 C) produced an epsilon of 10.2 ± 3.2 ‰. From these results it is concluded that there msy br multiple transport processes at work in CH4 transport through trees and the dominance of these processes clearly changes with temperature. Overall, the intra-tree transport mechanisms that dominates at lower temperatures and during lower fluxes results in a larger overall fractionation, while the transport mechanisms that prevail at higher temperatures and higher and higher overall fluxes produces a smaller isotopic fractionation. These findings, as well as additional lab and field-based measures will be presented. Finally, the implications of possibly distinct forms of CH4 gas transport within trees, and it's impact on understanding of biogeochemical processes, will be discussed.

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

    PubMed

    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.

  9. Method and apparatus for routing data in an inter-nodal communications lattice of a massively parallel computer system by routing through transporter nodes

    DOEpatents

    Archer, Charles Jens; Musselman, Roy Glenn; Peters, Amanda; Pinnow, Kurt Walter; Swartz, Brent Allen; Wallenfelt, Brian Paul

    2010-11-16

    A massively parallel computer system contains an inter-nodal communications network of node-to-node links. An automated routing strategy routes packets through one or more intermediate nodes of the network to reach a destination. Some packets are constrained to be routed through respective designated transporter nodes, the automated routing strategy determining a path from a respective source node to a respective transporter node, and from a respective transporter node to a respective destination node. Preferably, the source node chooses a routing policy from among multiple possible choices, and that policy is followed by all intermediate nodes. The use of transporter nodes allows greater flexibility in routing.

  10. Method and apparatus for routing data in an inter-nodal communications lattice of a massively parallel computer system by dynamically adjusting local routing strategies

    DOEpatents

    Archer, Charles Jens; Musselman, Roy Glenn; Peters, Amanda; Pinnow, Kurt Walter; Swartz, Brent Allen; Wallenfelt, Brian Paul

    2010-03-16

    A massively parallel computer system contains an inter-nodal communications network of node-to-node links. Each node implements a respective routing strategy for routing data through the network, the routing strategies not necessarily being the same in every node. The routing strategies implemented in the nodes are dynamically adjusted during application execution to shift network workload as required. Preferably, adjustment of routing policies in selective nodes is performed at synchronization points. The network may be dynamically monitored, and routing strategies adjusted according to detected network conditions.

  11. Method and apparatus for routing data in an inter-nodal communications lattice of a massively parallel computer system by employing bandwidth shells at areas of overutilization

    DOEpatents

    Archer, Charles Jens; Musselman, Roy Glenn; Peters, Amanda; Pinnow, Kurt Walter; Swartz, Brent Allen; Wallenfelt, Brian Paul

    2010-04-27

    A massively parallel computer system contains an inter-nodal communications network of node-to-node links. An automated routing strategy routes packets through one or more intermediate nodes of the network to reach a final destination. The default routing strategy is altered responsive to detection of overutilization of a particular path of one or more links, and at least some traffic is re-routed by distributing the traffic among multiple paths (which may include the default path). An alternative path may require a greater number of link traversals to reach the destination node.

  12. Identification of Phase Relationships and Incorporation Mechanisms of Barium in Calcite Internodes of Deep-Sea Bamboo Corals

    NASA Astrophysics Data System (ADS)

    Ptacek, J. L.; Geyman, B.; Horner, T. J.; Auro, M. E. E.; Hill, T. M.; LaVigne, M.

    2016-12-01

    Insufficient instrumental and geochemical records have led to a gap in knowledge of how intermediate/deep water masses respond to decadal shifts in surface atmospheric-ocean climate that drive changes in ocean ventilation, nutrient cycling, and export productivity. Due to their longevity, depth range (500-2000m), and radial growth bands, bamboo corals have been proposed as high-resolution intermediate/deep ocean archives of elements with nutrient-like distributions, such as barium. Previous work showed bamboo corals incorporate barium into their calcitic internodes with a near-constant proportionality to dissolved (Ba)sw, indicating that (Ba/Ca)coral may be a useful tracer of refractory nutrient distributions in the past. However, some intermediate- and deep-sea bamboo corals exhibit highly variable Ba/Ca, which may result from incorporation of extraneous Ba-bearing phases into coral skeletons (e.g. barite, organic matter, lithogenic particles) rather than true changes in ambient (Ba)SW. To this end, we developed and applied a sequential cleaning experiment to identify the host phases of Ba in coral samples recovered from the North Pacific California Margin oxygen minimum zone (800-2000m). Milled coral samples were homogenized and subjected to multiple cleaning protocols to isolate and remove detrital/fine grain particles (with H2O and HNO3), organic matter (with H2O2), and barite (with an alkaline DTPA solution), before Ba/Ca analysis via ICP-MS. We found that the cleaning process did not systematically alter the Ba/Ca of the samples, and analysis of powders via SEM BSE-EDS revealed no identifiable barite. Our preliminary results indicate that there is minimal incorporation of non-lattice bound barium phases by these corals, and further verifies the suggestion that the main driver of (Ba/Ca)coral is the incorporation of Ba2+ in proportion to (Ba)sw. The results of our study help to evaluate how the Ba/Ca proxy in deep-sea bamboo corals should be interpreted in

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

    PubMed

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

    2014-11-01

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

  14. Dense genetic linkage maps of three Populus species (Populus deltoides, P. nigra and P. trichocarpa) based on AFLP and microsatellite markers.

    PubMed Central

    Cervera, M T; Storme, V; Ivens, B; Gusmão, J; Liu, B H; Hostyn, V; Van Slycken, J; Van Montagu, M; Boerjan, W

    2001-01-01

    Populus deltoides, P. nigra, and P. trichocarpa are the most important species for poplar breeding programs worldwide. In addition, Populus has become a model for fundamental research on trees. Linkage maps were constructed for these three species by analyzing progeny of two controlled crosses sharing the same female parent, Populus deltoides cv. S9-2 x P. nigra cv. Ghoy and P. deltoides cv. S9-2 x P. trichocarpa cv. V24. The two-way pseudotestcross mapping strategy was used to construct the maps. Amplified fragment length polymorphism (AFLP) markers that segregated 1:1 were used to form the four parental maps. Microsatellites and sequence-tagged sites were used to align homoeologous groups between the maps and to merge linkage groups within the individual maps. Linkage analysis and alignment of the homoeologous groups resulted in 566 markers distributed over 19 groups for P. deltoides covering 86% of the genome, 339 markers distributed over 19 groups for P. trichocarpa covering 73%, and 369 markers distributed over 28 groups for P. nigra covering 61%. Several tests for randomness showed that the AFLP markers were randomly distributed over the genome. PMID:11404342

  15. The obscure events contributing to the evolution of an incipient sex chromosome in Populus A retrospective working hypothesis.

    SciTech Connect

    Tuskan, Gerald A; Tschaplinski, Timothy J; Chen, Jay; Labbe, Jessy L; Ranjan, Priya; DiFazio, Steven P; Slavov, Goncho T.; Yin, Tongming

    2012-01-01

    Genetic determination of gender is a fundamental developmental and evolutionary process in plants. Although it appears that dioecy in Populus is partially genetically controlled, the precise gender-determining systems remain unclear. The recently-released second draft assembly and annotated gene set of the Populus genome provided an opportunity to re-visit this topic. We hypothesized that over evolutionary time, selective pressure has reformed the genome structure and gene composition in the peritelomeric region of the chromosome XIX which has resulted in a distinctive genome structure and cluster of genes contributing to gender determination in Populus. Multiple lines of evidence support this working hypothesis. First, the peritelomeric region of the chromosome XIX contains significantly fewer single nucleotide polymorphisms than the rest of Populus genome and has a distinct evolutionary history. Second, the peritelomeric end of chromosome XIX contains the largest cluster of the nucleotide-binding site-leucine-rich repeat (NBS-LRR) class of disease resistances genes in the entire Populus genome. Third, there is a high occurrence of small microRNAs on chromosome XIX coincident to the region containing the putative gender-determining locus and the major cluster of NBS-LRR genes. Further, by analyzing the metabolomic profiles of floral bud in male and female Populus trees using a gas chromatography-mass spectrometry, we found there are gender-specific accumulations of phenolic glycosides. Taken together, these findings provide new insights into the genetic control of gender determination in Populus.

  16. Seedling competition between native Populus deltoides (Salicaceae) and exotic Tamarix ramosissima (Tamaricaceae) across water regimes and substrate types.

    PubMed

    Sher, Anna A; Marshall, Diane L

    2003-03-01

    Populus deltoides subsp. wislizinii (Salicaceae), a cottonwood native to the Middle Rio Grande of New Mexico, must potentially compete against exotic Tamarix ramosissima (Tamaricaceae) during establishment after flooding. We investigated competitive interactions between seedlings of Tamarix and Populus in two substrates representing field textures and declining (i.e., draw-down) or stagnant water tables. The experiment was performed using a full-additive series design and interpreted with response surface models for each species. As reflected in both aboveground mass and height, Populus suppressed aboveground growth of Tamarix across all treatments, whereas competitive effects of Tamarix against Populus could only be seen at low Populus densities. Clay substrates with draw-down stimulated the greatest growth and created the most intense competitive environment for both species. Tamarix was competitively suppressed in every substrate tested, with the weakest response in sand with no draw-down, where growth of Populus was poorest. These results suggest that stream flow management that promotes Populus establishment could also aid in controlling Tamarix invasion across a range of substrates.

  17. Expansion and diversification of the SET domain gene family following whole-genome duplications in Populus trichocarpa.

    PubMed

    Lei, Li; Zhou, Shi-Liang; Ma, Hong; Zhang, Liang-Sheng

    2012-04-12

    Histone lysine methylation modifies chromatin structure and regulates eukaryotic gene transcription and a variety of developmental and physiological processes. SET domain proteins are lysine methyltransferases containing the evolutionarily-conserved SET domain, which is known to be the catalytic domain. We identified 59 SET genes in the Populus genome. Phylogenetic analyses of 106 SET genes from Populus and Arabidopsis supported the clustering of SET genes into six distinct subfamilies and identified 19 duplicated gene pairs in Populus. The chromosome locations of these gene pairs and the distribution of synonymous substitution rates showed that the expansion of the SET gene family might be caused by large-scale duplications in Populus. Comparison of gene structures and domain architectures of each duplicate pair indicated that divergence took place at the 3'- and 5'-terminal transcribed regions and at the N- and C-termini of the predicted proteins, respectively. Expression profile analysis of Populus SET genes suggested that most Populus SET genes were expressed widely, many with the highest expression in young leaves. In particular, the expression profiles of 12 of the 19 duplicated gene pairs fell into two types of expression patterns. The 19 duplicated SET genes could have originated from whole genome duplication events. The differences in SET gene structure, domain architecture, and expression profiles in various tissues of Populus suggest that members of the SET gene family have a variety of developmental and physiological functions. Our study provides clues about the evolution of epigenetic regulation of chromatin structure and gene expression.

  18. Regeneration Capacity of Small Clonal Fragments of the Invasive Mikania micrantha H.B.K.: Effects of Burial Depth and Stolon Internode Length

    PubMed Central

    Li, Xiaoxia; Shen, Yide; Huang, Qiaoqiao; Fan, Zhiwei; Huang, Dongdong

    2013-01-01

    The perennial stoloniferous herbaceous vine Mikania micrantha H.B.K. is among the most noxious exotic invaders in China and the world. Disturbance can fragment stolons of M. micrantha and disperse these fragments over long distances or bury them in soils at different depths. To test their regeneration capacity, single-node stolon fragments with stolon internode lengths of 0, 3, 6 and 12 cm were buried in soil at 0, 2, 5 and 8 cm depths, respectively. The fragments were growing for nine weeks, and their emergence status, growth and morphological traits were measured. The results indicated that increasing burial depth significantly decreased survival rate and increased the emergence time of the M. micrantha plants. At an 8-cm burial depth, very few fragments (2.19%) emerged and survived. Burial did not affect the total biomass and root to shoot ratio of the surviving M. micrantha plants that emerged from the 0- and 2-cm burial depths. Increasing internode length significantly increased survival rate and growth measures, but there was no interaction effect with burial depth for any traits measured. These results suggest that M. micrantha can regenerate from buried stolon fragments, and thus, disturbance may contribute to the spread of this exotic invader. Any human activities producing stolon fragments or facilitating dispersal should be avoided. PMID:24367686

  19. The effect of mepiquat chloride on elongation of cotton (Gossypium hirsutum L.) internode is associated with low concentration of gibberellic acid.

    PubMed

    Wang, Li; Mu, Chun; Du, Mingwei; Chen, Yin; Tian, Xiaoli; Zhang, Mingcai; Li, Zhaohu

    2014-08-01

    The growth regulator mepiquat chloride (MC) is globally used in cotton (Gossypium hirsutum L.) canopy manipulation to avoid excess growth and yield loss. However, little information is available as to whether the modification of plant architecture by MC is related to alterations in gibberellic acid (GA) metabolism and signaling. Here, the role of GA metabolism and signaling was investigated in cotton seedlings treated with MC. The MC significantly decreased endogenous GA3 and GA4 levels in the elongating internode, which inhibited cell elongation by downregulating GhEXP and GhXTH2, and then reducing plant height. Biosynthetic and metabolic genes of GA were markedly suppressed within 2-10d of MC treatment, which also downregulated the expression of DELLA-like genes. A remarkable feedback regulation was observed at the early stage of MC treatment when GA biosynthetic and metabolic genes expression was evidently upregulated. Mepiquat chloride action was controlled by temporal translocation and spatial accumulation which regulated GA biosynthesis and signal expression for maintaining GA homeostasis. The results suggested that MC application could reduce endogenous GA levels in cotton through controlled GA biosynthetic and metabolic genes expression, which might inhibit cell elongation, thereby shortening the internode and reducing plant height.

  20. Identification of a 98-kb DNA segment containing the rice Eui gene controlling uppermost internode elongation, and construction of a TAC transgene sublibrary.

    PubMed

    Xu, Y-H; Zhu, Y-Y; Zhou, H-C; Li, Q; Sun, Z-X; Liu, Y-G; Lin, H-X; He, Z-H

    2004-09-01

    The recessive 'tall rice' phenotype associated with the mutation eui (elongated upper-most internode) is an important agronomic trait that has been introduced into hybrid rice to eliminate panicle enclosure in all types of male-sterile lines and produce good-quality seeds in high yield and at low cost. Based on our previous Eui mapping data, we conducted fine-structure mapping and positional cloning of the gene using an F2 population comprising more than 5000 individuals derived from a cross of the near-isogenic lines 307T (eui/eui) with the recurrent parent Zhenshan 97 (Eui/Eui). In total 45 CAPS (cleaved amplified polymorphic sequences) markers located within an interval of 14.5 cM were analyzed in the subpopulation of 1298 homozygous recessive plants. The resulting high-resolution map defined a 98-kb interval containing the Eui locus flanked by the markers M0387 and M01, and three markers were found to co-segregate with Eui. In order to facilitate the identification of the Eui gene, we used a transformation-competent artificial chromosome (TAC) vector to construct a set of contiguous TAC clones from the Nipponbare BACs (obtained from the Clemson University Genome Institute; CUGI) spanning this region. These clones can be used to streamline complementation testing. The markers tightly linked to the Eui locus can also be used in breeding male-sterile lines with the elongated uppermost internode.

  1. Identification of genes involved in cell wall biogenesis in grasses by differential gene expression profiling of elongating and non-elongating maize internodes

    PubMed Central

    Bosch, Maurice; Mayer, Claus-Dieter; Cookson, Alan; Donnison, Iain S.

    2011-01-01

    Despite the economic importance of grasses as food, feed, and energy crops, little is known about the genes that control their cell wall synthesis, assembly, and remodelling. Here a detailed transcriptome analysis that allowed the identification of genes involved in grass cell wall biogenesis is provided. Differential gene expression profiling, using maize oligonucleotide arrays, was used to identify genes differentially expressed between an elongating internode, containing cells exhibiting primary cell wall synthesis, and an internode that had just ceased elongation and in which many cells were depositing secondary cell wall material. This is one of only a few studies specifically aimed at the identification of cell wall-related genes in grasses. Analysis identified new candidate genes for a role in primary and secondary cell wall biogenesis in grasses. The results suggest that many proteins involved in cell wall processes during normal development are also recruited during defence-related cell wall remodelling events. This work provides a platform for studies in which candidate genes will be functionally tested for involvement in cell wall-related processes, increasing our knowledge of cell wall biogenesis and its regulation in grasses. Since several grasses are currently being developed as lignocellulosic feedstocks for biofuel production, this improved understanding of grass cell wall biogenesis is timely, as it will facilitate the manipulation of traits favourable for sustainable food and biofuel production. PMID:21402660

  2. Effect of litter, leaf cover and cover of basal internodes of the dominant species Molinia caerulea on seedling recruitment and established vegetation

    NASA Astrophysics Data System (ADS)

    Janeček, Štěpán; Lepš, Jan

    2005-09-01

    The effects of litter removal, leaf cover of established plants and cover of basal internodes of a dominant species Molinia caerulea on seedling germination and the dynamics of established plants were studied in a field experiment in an oligotrophic wet meadow. Although the negative influence of litter on total seedling number and seedling species composition was non-significant, litter significantly affected the dynamics of the established vegetation and caused inhibition of total leaf cover development. The effects of total leaf cover of established plants on seedling establishment changed during the vegetation season. Whereas the effect of total leaf cover was positive at the start and in the middle of the vegetation season, at the end the total leaf cover negatively affected seedling establishment. Both total leaf cover and cover of basal internodes affected seedling composition. Effects of these two variables were statistically separable suggesting that they are based on different mechanisms. The response of seedling establishment to these factors was species specific and, consequently, our data support the hypothesis that that biotically generated spatial heterogeneity can promote species co-existence through the differentiation of species regeneration niches.

  3. Regeneration capacity of small clonal fragments of the invasive Mikania micrantha H.B.K.: effects of burial depth and stolon internode length.

    PubMed

    Li, Xiaoxia; Shen, Yide; Huang, Qiaoqiao; Fan, Zhiwei; Huang, Dongdong

    2013-01-01

    The perennial stoloniferous herbaceous vine Mikania micrantha H.B.K. is among the most noxious exotic invaders in China and the world. Disturbance can fragment stolons of M. micrantha and disperse these fragments over long distances or bury them in soils at different depths. To test their regeneration capacity, single-node stolon fragments with stolon internode lengths of 0, 3, 6 and 12 cm were buried in soil at 0, 2, 5 and 8 cm depths, respectively. The fragments were growing for nine weeks, and their emergence status, growth and morphological traits were measured. The results indicated that increasing burial depth significantly decreased survival rate and increased the emergence time of the M. micrantha plants. At an 8-cm burial depth, very few fragments (2.19%) emerged and survived. Burial did not affect the total biomass and root to shoot ratio of the surviving M. micrantha plants that emerged from the 0- and 2-cm burial depths. Increasing internode length significantly increased survival rate and growth measures, but there was no interaction effect with burial depth for any traits measured. These results suggest that M. micrantha can regenerate from buried stolon fragments, and thus, disturbance may contribute to the spread of this exotic invader. Any human activities producing stolon fragments or facilitating dispersal should be avoided.

  4. Characterization of Dof Transcription Factors and Their Responses to Osmotic Stress in Poplar (Populus trichocarpa).

    PubMed

    Wang, Han; Zhao, Shicheng; Gao, Yuchi; Yang, Jingli

    2017-01-01

    The DNA-binding One Zinc Finger (Dof) genes are ubiquitous in many plant species and are especial transcription regulators that participate in plant growth, development and various procedures, including biotic and abiotic stress reactions. In this study, we identified 41 PtrDof members from Populus trichocarpa genomes and classified them into four groups. The conserved motifs and gene structures of some PtrDof genes belonging to the same subgroup were almost the same. The 41 PtrDof genes were dispersed on 18 of the 19 Populus chromosomes. Many key stress- or phytohormone-related cis-elements were discovered in the PtrDof gene promoter regions. Consequently, we undertook expression profiling of the PtrDof genes in leaves and roots in response to osmotic stress and abscisic acid. A total of seven genes (PtrDof14, 16, 25, 27, 28, 37 and 39) in the Populus Dof gene family were consistently upregulated at point in all time in the leaves and roots under osmotic and abscisic acid (ABA) stress. We observed that 12 PtrDof genes could be targeted by 15 miRNAs. Moreover, we mapped the cleavage site in PtrDof30 using the 5'RLM-RACE. The results showed that PtrDofs may have a role in resistance to abiotic stress in Populus trichocarpa.

  5. Influence of irrigation and fertilization on transpiration and hydraulic properties of Populus deltoides

    Treesearch

    Lisa J. Samuelson; Thomas A. Stokes; Mark D. Coleman

    2007-01-01

    Long-term hydraulic acclimation to resource availability was explored in 3-year-old Populus deltoides Bartr. ex Marsh. clones by examining transpiration. leaf-specific hydraulic conductance (GL), canopy stomatal conductance (Gs) and leaf to sapwood area ratio (AL:Asi)n response to irrigation (13 and 551 mm in addition to ambient precipitation) and...

  6. Gibberellin-associated cisgenes modify growth, stature and wood properties in Populus

    USDA-ARS?s Scientific Manuscript database

    We studied the effects on plant growth from insertion of five cisgenes involved in gibberellic acid metabolism or signaling. We cloned intact genomic copies of GA20ox7, GA2ox2, RGL1_1, RGL1_2, and GAI1 genes from the genome sequenced Populus trichocarpa clone Nisqually-1, transformed them into Popul...

  7. Genome structure and emerging evidence of an incipient sex chromosome in Populus

    SciTech Connect

    Yin, Tongming; DiFazio, Stephen P; Gunter, Lee E; Zhang, Xinye; Sewell, Mitchell; Woolbright, Dr. Scott; Allan, Dr. Gery; Kelleher, Colin; Douglas, Carl; Wang, Prof. Mingxiu; Tuskan, Gerald A

    2008-01-01

    The genus Populus consists of dioecious woody species with largely unknown genetic mechanisms for gender determination. We have discovered genetic and genomic features in the peritelomeric region of chromosome XIX that suggest this region of the Populus genome is in the process of developing characteristics of a sex chromosome. We have identified a gender-associated locus that consistently maps to this region. Furthermore, comparison of genetic maps across multiple Populus families reveals consistently distorted segregation within this region. We have intensively characterized this region using an F1 interspecific cross involving the female genotype that was used for genome sequencing. This region shows suppressed recombination and high divergence between the alternate haplotypes, as revealed by dense map-based genome assembly using microsatellite markers. The suppressed recombination, distorted segregation, and haplotype divergence were observed only for the maternal parent in this cross. Furthermore, the progeny of this cross showed a strongly male-biased sex ratio, in agreement with Haldane's rule that postulates that the heterogametic sex is more likely to be absent, rare, or sterile in interspecific crosses. Together, these results support the role of chromosome XIX in sex determination and suggest that sex determination in Populus occurs through a ZW system in which the female is the heterogametic gender.

  8. Characterization of Dof Transcription Factors and Their Responses to Osmotic Stress in Poplar (Populus trichocarpa)

    PubMed Central

    Wang, Han; Zhao, Shicheng; Gao, Yuchi; Yang, Jingli

    2017-01-01

    The DNA-binding One Zinc Finger (Dof) genes are ubiquitous in many plant species and are especial transcription regulators that participate in plant growth, development and various procedures, including biotic and abiotic stress reactions. In this study, we identified 41 PtrDof members from Populus trichocarpa genomes and classified them into four groups. The conserved motifs and gene structures of some PtrDof genes belonging to the same subgroup were almost the same. The 41 PtrDof genes were dispersed on 18 of the 19 Populus chromosomes. Many key stress- or phytohormone-related cis-elements were discovered in the PtrDof gene promoter regions. Consequently, we undertook expression profiling of the PtrDof genes in leaves and roots in response to osmotic stress and abscisic acid. A total of seven genes (PtrDof14, 16, 25, 27, 28, 37 and 39) in the Populus Dof gene family were consistently upregulated at point in all time in the leaves and roots under osmotic and abscisic acid (ABA) stress. We observed that 12 PtrDof genes could be targeted by 15 miRNAs. Moreover, we mapped the cleavage site in PtrDof30 using the 5’RLM-RACE. The results showed that PtrDofs may have a role in resistance to abiotic stress in Populus trichocarpa. PMID:28095469

  9. Evaluation of Populus and Salix continuously irrigated with landfill leachate I. Genotype-specific elemental phytoremediation

    Treesearch

    Ronald S., Jr. Zalesny; Edmund O. Bauer

    2007-01-01

    There is a need for the identification and selection of specific tree genotypes that can sequester elements from contaminated soils, with elevated rates of uptake. We irrigated Populus (DN17, DN182, DN34, NM2, NM6) and Salix (94003, 94012, S287, S566, SX61) genotypes planted in large soil-filled containers with landfill leachate or...

  10. Sodium and chloride concentration in leaf, woody, and root tissue of Populus irrigated with landfill leachate

    Treesearch

    Jill A. Zalesny; Ronald S., Jr. Zalesny; A.H. Wiese; B. Sexton; R.B. Hall

    2007-01-01

    There are few reports in the literature about the response of different genomic groups and clones of Populus to elevated levels of sodium (Na+) and chloride (Cl-). In addition, there is an increasing need to understand the variation in salt tolerance and tissue composition of such genotypes over multiple...

  11. Effects of ozone and sulfur dioxide on height and stem specific gravity of Populus hybrids

    Treesearch

    Roy L. Patton

    1981-01-01

    Unfumigated hybrid poplars (Populus spp.) were compared with poplars of the same nine clones fumigated with 0.15 pprn ozone or 0.25 ppm sulfur dioxide. After 102 days, plant height and stem specific gravity were measured to determine whether specific gravity is altered by the fumigants and to compare that response to height suppression, an accepted...

  12. Cutting Diameter Influences Early Survival and Growth of Several Populus Clones

    Treesearch

    Donald Dickmann; Howard Phipps; Daniel Netzer

    1980-01-01

    The effects of cutting diameter on early survival and growth of several Populus clones were studied in field tests in Wisconsin and Michigan. Generally, large diameter cuttings survived and grew better than small diameter cuttings. Response differences among clones were evident.

  13. Use of belowground growing degree days to predict rooting of dormant hardwood cuttings of Populus

    Treesearch

    R.S., Jr. Zalesny; E.O. Bauer; D.E. Riemenschneider

    2004-01-01

    Planting Populus cuttings based on calendar days neglects soil temperature extremes and does not promote rooting based on specific genotypes. Our objectives were to: 1) test the biological efficacy of a thermal index based on belowground growing degree days (GDD) across the growing period, 2) test for interactions between belowground GDD and clones,...

  14. Extensive structural renovation of retrogenes in the evolution of the Populus genome.

    PubMed

    Zhu, Zhenglin; Zhang, Yong; Long, Manyuan

    2009-12-01

    Retroposition, as an important copy mechanism for generating new genes, was believed to play a negligible role in plants. As a representative dicot, the genomic sequences of Populus (poplar; Populus trichocarpa) provide an opportunity to investigate this issue. We identified 106 retrogenes and found the majority (89%) of them are associated with functional signatures in sequence evolution, transcription, and (or) translation. Remarkably, examination of gene structures revealed extensive structural renovation of these retrogenes: we identified 18 (17%) of them undergoing either chimerization to form new chimerical genes and (or) intronization (transformation into intron sequences of previously exonic sequences) to generate new intron-containing genes. Such a change might occur at a high speed, considering eight out of 18 such cases occurred recently after divergence between Arabidopsis (Arabidopsis thaliana) and Populus. This pattern also exists in Arabidopsis, with 15 intronized retrogenes occurring after the divergence between Arabidopsis and papaya (Carica papaya). Thus, the frequency of intronization in dicots revealed its importance as a mechanism in the evolution of exon-intron structure. In addition, we also examined the potential impact of the Populus nascent sex determination system on the chromosomal distribution of retrogenes and did not observe any significant effects of the extremely young sex chromosomes.

  15. Extensive Structural Renovation of Retrogenes in the Evolution of the Populus Genome1[W][OA

    PubMed Central

    Zhu, Zhenglin; Zhang, Yong; Long, Manyuan

    2009-01-01

    Retroposition, as an important copy mechanism for generating new genes, was believed to play a negligible role in plants. As a representative dicot, the genomic sequences of Populus (poplar; Populus trichocarpa) provide an opportunity to investigate this issue. We identified 106 retrogenes and found the majority (89%) of them are associated with functional signatures in sequence evolution, transcription, and (or) translation. Remarkably, examination of gene structures revealed extensive structural renovation of these retrogenes: we identified 18 (17%) of them undergoing either chimerization to form new chimerical genes and (or) intronization (transformation into intron sequences of previously exonic sequences) to generate new intron-containing genes. Such a change might occur at a high speed, considering eight out of 18 such cases occurred recently after divergence between Arabidopsis (Arabidopsis thaliana) and Populus. This pattern also exists in Arabidopsis, with 15 intronized retrogenes occurring after the divergence between Arabidopsis and papaya (Carica papaya). Thus, the frequency of intronization in dicots revealed its importance as a mechanism in the evolution of exon-intron structure. In addition, we also examined the potential impact of the Populus nascent sex determination system on the chromosomal distribution of retrogenes and did not observe any significant effects of the extremely young sex chromosomes. PMID:19789289

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

    PubMed

    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.

  17. Inheritance of compartmentalization of wounds in sweetgum (Liquidambar styraciflua L.) and eastern cottonwood (Populus deltoides Bartr.)

    Treesearch

    P. W. Garrett; W. K. Randall; A. L. Shigo; W. C. Shortle

    1979-01-01

    Studies of half-sib progeny tests of sweetgum (Liquidambar styraciflua) and clonal plantings of eastern cottonwood (Populus deltoides) in Mississippi indicate that rate of wound closure and size of discolored columns associated with the wounds are both heritable traits. Both are independent of stem diameter, which was used as a...

  18. Intercontinental divergence in the Populus-associated ectomycorrhizal fungus, Tricholoma populinum

    Treesearch

    L.C. Grubisha; N. Levsen; M.S. Olson; D.L. Taylor

    2012-01-01

    The ectomycorrhizal fungus Tricholoma populinum is host-specific with Populus species. T. populinum has wind-dispersed progagules and may be capable of long-distance dispersal. In this study, we tested the hypothesis of a panmictic population between Scandinavia and North America. DNA sequences from five...

  19. Leaf chemical composition of twenty-one Populus hybrid clones grown under intensive culture

    Treesearch

    Richard E. Dickson; Philip R. Larson

    1976-01-01

    Leaf material from 21 nursery-grown Populus hybrid clones was analyzed for three nitrogen fractions (total N, soluble protein, and soluble amino acids) and three carbhydrate fractions (reducing sugars, total soluble sugars, and total nonstructural carbohydrates-TNC). In addition, nursery-grown green ash and silver maple, field-grown bigtooth and trembling aspen, and...

  20. Draft Genome Sequence of the Growth-Promoting Endophyte Paenibacillus sp. P22, Isolated from Populus

    PubMed Central

    Hanak, Anne M.; Nagler, Matthias; Weinmaier, Thomas; Sun, Xiaoliang; Fragner, Lena; Schwab, Clarissa; Rattei, Thomas; Ulrich, Kristina; Ewald, Dietrich; Engel, Marion; Schloter, Michael; Bittner, Romana; Schleper, Christa

    2014-01-01

    Paenibacillus sp. P22 is a Gram-negative facultative anaerobic endospore-forming bacterium isolated from poplar hybrid 741 (♀[Populus alba × (P. davidiana + P. simonii) × P. tomentosa]). This bacterium shows strong similarities to Paenibacillus humicus, and important growth-promoting effects on in vitro grown explants of poplar hybrid 741 have been described. PMID:24723717

  1. Using phyto-recurrent selection to choose Populus genotypes for phytoremediation of landfill leachate

    Treesearch

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

    2006-01-01

    Information about the response of Populus genotypes to landfill leachate irrigation is needed, along with efficient methods for choosing genotypes based on leachate composition. We irrigated poplar clones during three cycles of phyto-recurrent selection to test whether genotypes responded differently to leachate and water, and to test whether our...

  2. Above- and below-ground characteristics associated with wind toppling in a young Populus plantation.

    Treesearch

    Constance A. Harrington; Dean S. DeBell

    1996-01-01

    Damage from a dormant-season windstorm in a 3-year-old Populus research trial differed among four clones and three spacings and between monoclonal and polyclonal plots. Clonal differences in susceptibility to toppling (or leaning) were associated with both above and below-ground characteristics. Susceptible clones had less taper in the lower stem...

  3. Draft genome sequences of four Streptomyces isolates from the Populus trichocarpa root endosphere and rhizosphere

    DOE PAGES

    Klingeman, Dawn M.; Utturkar, Sagar; Lu, Tse -Yuan S.; ...

    2015-11-12

    Draft genome sequences for four Actinobacteria from the genus Streptomyces are presented. Streptomyces is a metabolically diverse genus that is abundant in soils and has been reported in association with plants. The strains described in this study were isolated from the Populus trichocarpa endosphere and rhizosphere.

  4. Transcriptional and Hormonal Regulation of Gravitropism of Woody Stems in Populus

    Treesearch

    Suzanne Gerttula; Matthew S. Zinkgraf; Gloria K. Muday; Daniel R. Lewis; Farid M. Ibatullin; Harry Brumer; Foster Hart; Shawn D. Mansfield; Vladimir Filkov; Andrew Groover

    2015-01-01

    Angiosperm trees reorient their woody stems by asymmetrically producing a specialized xylem tissue, tension wood, which exerts a strong contractile force resulting in negative gravitropism of the stem. Here, we show, in Populus trees, that initial gravity perception and response occurs in specialized cells through sedimentation of starch-filled...

  5. Productivity of Populus in monoclonal and polyclonal blocks at three spacings.

    Treesearch

    Dean S. DeBell; Constance A. Harrington

    1997-01-01

    Four Populus clones were grown at three spacings (0.5, 1.0, and 1.5 m) in monoclonal plots and in polyclonal plots with all clones in intimate mixture. After the third year, many individual tree and stand traits differed significantly by clone, spacing, deployment method, and their interactions. Differences among clones in growth and stem form were...

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

    SciTech Connect

    Tschaplinski, Timothy J; Tsai, Chung-Jui; Harding, Scott A; Lindroth, richard L; Yuan, Yinan

    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.

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

    SciTech Connect

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

    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.

  8. Mensurational and Biomass Relations for Populus ''Tristis #1'' Under Intensive Culture

    Treesearch

    Alan R. Ek

    1980-01-01

    Tree measurement data from plantations established in 1970 and 1973 and grown under intensive culture were used to establish various dimensional relations and biomass equations for Populus ''Tristis #1''. These equations subsequently have been used to estimate yields on study plots and for projections of future yields. They are presented here for...

  9. Selecting Populus with different adventitious root types for environmental benefits, fiber, and energy

    Treesearch

    Ronald S., Jr. Zalesny; Jill A. Zalesny

    2009-01-01

    Primary roots from seeds, sucker roots in aspens, and adventitious roots (ARs) in poplars and their hybrids are prevalent within the genus Populus. Two AR types develop on hardwood cuttings: (i) lateral roots from either preformed or induced primordia along the length of the cutting and (ii) basal roots from callus at the base of the cutting in...

  10. Differential interspecific incompatibility among Populus hybrids in sections Aigeiros Duby and Tacamahaca Spach

    Treesearch

    Assiti A. Mahama; Richard B. Hall; Ronald S. Zalesny

    2011-01-01

    In our previous Populus breeding, compatible crosses between P. maximowiczii A. Henry and P. deltoides Bartr. ex Marsh corroborated the potential of interspecific hybrids, despite low seed set. Our current objective was to test the range of incompatibility among intraspecific and interspecific crosses using...

  11. Bulked segregant analysis identifies molecular markers linked to Melampsora medusae resistance in Populus deltoides

    Treesearch

    G. M. Tabor; Thomas L. Kubisiak; N. B. Klopfenstein; R. B. Hall; Henry S. McNabb

    2000-01-01

    In the north central United States, leaf rust caused by Melampsora medusae is a major disease problem on Populus deltoides. In this study we identified molecular markers linked to a M. medusae resistance locus (Lrd1) that was segregating 1:1 within an intraspecific P. deltoides...

  12. Selecting and utilizing Populus and Salix for landfill covers: implications for leachate irrigation

    Treesearch

    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. Environmental Influences on Wood Chemistry and Density of Populus and Loblolly Pine

    SciTech Connect

    Tuskan, G.A.

    2006-08-11

    The objectives of the study are to: (1) determine the degree to which physical and chemical wood properties vary in association with environmental and silvicultural practices in Populus and loblolly pine and (2) develop and verify species-specific empirical models in an effort to create a framework for understanding environmental influences on wood quality.

  14. Carbon allocation and nitrogen acquisition in a developing Populus deltoides plantation

    Treesearch

    Mark D. Coleman; Alexander L. Friend; Christel C. Kern

    2004-01-01

    We established Populus deltoides Bartr. stands differing in nitrogen (N) availability and tested if: (1) N-induced carbon (C) allocation could be explained by developmental allocation controls; and (2) N uptake per unit root mass, i.e., specific N-uptake rate, increased with N availability. Closely spaced (1 x 1 m) stands were treated with 50, 100...

  15. Early root development of poplars ( Populus spp.) in relation to moist and saturated soil conditions

    Treesearch

    Rebecka Mc Carthy; Magnus Löf; Emile S. Gardiner

    2017-01-01

    Poplars (Populus spp.) are among the fastest growing trees raised in temperate regions of the world. Testing of newly developed cultivars informs assessment of potential planting stock for local environments. Initial rooting by nine poplar clones was tested in moist and saturated soil conditions during an 18-day greenhouse experiment. Clones responded differently to...

  16. RepPop: A Database for Repetitive Elements in Populus Trichocarpa

    DOE Data Explorer

    Zhou, Fengfeng; Xu, Ying

    The populus was selected as the first tree with the genome to be sequenced, mainly due to its small genome size, the wide deployment worldwide (30+ species), and its short juvenile period. Its rich content of cellulose, which is one of the most important source for biofuel. A female clone of P. trichocarpa was chosen to be sequenced. The current assembly of Populus genome is release 1.0, whose small insert end-sequence coverage is 7.5X, and it was released in June 2004. It consists of 22,012 sequences (including the 19 chromosomes) and the total length is 485,510,911 bps. The data was downloaded from the offical site of the Populus trichocarpa genome sequencing project. The latest version of the genome can be found at the Poplar Genome Project at JGI Eukaryotic Genomics. Duplication regions introduce significant difficulties into the correct assemblying of sequence contigs. We identified all the repetitive elements in the populus genome. We further assign each of them as different classes of repetitive elements, including DNA transposons, RNA retrotransposons, Miniature Inverted-repeat Transposable Elements (MITE), Simple Sequence Repeats (SSR), and Segmental Duplications (SD), etc. We organized the annotations into this easily browsable, searchable, and blastable database, RepPop, for the whole community.[From website for RepPop at http://csbl.bmb.uga.edu/~ffzhou/RepPop/

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

    Treesearch

    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...

  18. Chloride and sodium uptake potential over an entire rotation of Populus irrigated with landfill leachate

    Treesearch

    Jill A. Zalesny; Ronald S., Jr. Zalesny

    2009-01-01

    There is a need for information about the response of Populus genotypes to repeated application of high-salinity water and nutrient sources throughout an entire rotation. We have combined establishment biomass and uptake data with mid- and full-rotation growth data to project potential chloride (Cl−) and sodium (Na...

  19. Drought effects on leaf abscission and leaf production in Populus clones

    Treesearch

    Stephen G. Pallardy; Julie L. Rhoads

    1997-01-01

    Leaf abscission and foliation responses to water stress were studied in potted plants of five Populus clones grown in a greenhouse. As predawn leaf water potential (Ψ1) fell to -3 MPa, drought-induced leaf abscission increased progressively to 30% for data pooled across clones. As predawn Ψ1...

  20. The practice and physiological basis of collecting, storing and planting Populus hardwood cuttings

    Treesearch

    Anne S. Fege

    1983-01-01

    Producing healthy hardwood cuttings for Populus plantation establishment requires attention to the management of clonal nurseries, timely collection of cuttings, adequate grading of cuttings, storage temperature and conditions, preplanting treatments, and planting operations. Recommended nursery practices are outlined, along with their grounding in...

  1. Recent advances in research of some pest problems of hybrid populus in Michigan and Wisconsin

    Treesearch

    Lincoln M. Moore; Louis F. Wilson

    1983-01-01

    Hybrid Populus clones were examined for impact from and resistance to attack from several insects and diseases. Cottonwood leaf beetle, poplar-and-willow borer, and Septoria canker were most injurious. The spotted poplar aphid and poplar-gall saperda, even when abundant, caused only minor impact. The tarnished plant bug, a newly identified pest of...

  2. Populus seed fibers as a natural source for production of oil super absorbents.

    PubMed

    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. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Shoot position affects root initiation and growth of dormant unrooted cuttings of Populus

    Treesearch

    R.S., Jr. Zalesny; R.B. Hall; E.O. Bauer; D.E. Riemenschneider

    2003-01-01

    Rooting of dormant unrooted cuttings is crucial to the commercial deployment of intensively cultured poplar (Populus spp.) plantations because it is the first biological prerequisite to stand establishment. Rooting can be genetically controlled and subject to selection. Thus, our objective was to test for differences in rooting ability among cuttings...

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

    Treesearch

    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 ...

  5. Soil temperature and precipitation affect the rooting ability of dormant hardwood cuttings of Populus

    Treesearch

    R.S., Jr. Zalesny; R.B. Hall; E.O. Bauer; D.E. Riemenschneider

    2005-01-01

    In addition to genetic control, responses to environmental stimuli affect the success of rooting. Our objectives were to: 1) assess the variation in rooting ability among 21 Populus clones grown under varying soil temperatures and amounts of precipitation and 2) identify combinations of soil temperature and precipitation that promote rooting. The...

  6. Bud removal affects shoot, root, and callus development of hardwood Populus cuttings

    Treesearch

    A.H. Wiese; J.A. Zalesny; D.M. Donner; Ronald S., Jr. Zalesny

    2006-01-01

    The inadvertent removal and/or damage of buds during processing and planting of hardwood poplar (Populus spp.) cuttings are a concern because of their potential impact on shoot and root development during establishment. The objective of the current study was to test for differences in shoot dry mass, root dry mass, number of roots, length of the...

  7. Anatomy and dry weight yields of two Populus clones grown under intensive culture.

    Treesearch

    John B. Crist; David H. Dawson

    1975-01-01

    Two Populus clones grown for short rotations at three dense planting spacings produced some extremely high yields of material of acceptable quality. However, variation in yields and quality illustrates that selection of genetic material and the cultured regime under which a species is growth are significant factors that must be determined in maximum-yield systems....

  8. Cryopreservation of Populus trichocarpa and Salix using dormant buds with recovery by grafting or direct rooting

    USDA-ARS?s Scientific Manuscript database

    Populus trichocarpa and Salix can be successfully cryopreserved by using dormant scions as the source explants. These scions (either at their original moisture content of 48 to 60% or dried to 30%) were slowly cooled to –35 degree Celsius, transferred to the vapor phase of liquid nitrogen (LNV,-160...

  9. Influence of Populus Genotype on Gene Expression by the Wood Decay Fungus Phanerochaete chrysosporium

    Treesearch

    Jill Gaskell; Amber Marty; Michael Mozuch; Philip J. Kersten; Sandra Splinter Bondurant; Grzegorz Sabat; Ali Azarpira; John Ralph; Oleksandr Skyba; Shawn D. Mansfield; Robert A. Blanchette; Dan Cullen

    2014-01-01

    We examined gene expression patterns in the lignin-degrading fungus Phanerochaete chrysosporium when it colonizes hybrid poplar (Populus alba tremula) and syringyl (S)-rich transgenic derivatives. Acombination ofmicroarrays and liquid chromatography- tandem mass spectrometry (LC-MS/MS) allowed detection of a total of 9,959 transcripts and 793...

  10. Evaluation of Populus and Salix continuously irrigated with landfill leachate II. Soils and early tree development

    Treesearch

    Ronald S., Jr. Zalesny; Edmund O. Bauer

    2007-01-01

    Soil contaminant levels and early tree growth data are helpful for assessing phytoremediation systems. Populus (DN17, DN182, DN34, NM2, and NM6) and Salix (94003, 94012, S287, S566, and SX61) genotypes were irrigated with landfill leachate or municipal water and tested for differences in 1) element concentrations (P, K, Ca, Mg, S,...

  11. Transcriptomic analysis of Clostridium thermocellum Populus hydrolysate-tolerant mutant strain shows increased cellular efficiency in response to Populus hydrolysate compared to the wild type strain

    PubMed Central

    2014-01-01

    Background The thermophilic, anaerobic bacterium, Clostridium thermocellum is a model organism for consolidated processing due to its efficient fermentation of cellulose. Constituents of dilute acid pretreatment hydrolysate are known to inhibit C. thermocellum and other microorganisms. To evaluate the biological impact of this type of hydrolysate, a transcriptomic analysis of growth in hydrolysate-containing medium was conducted on 17.5% v/v Populus hydrolysate-tolerant mutant (PM) and wild type (WT) strains of C. thermocellum. Results In two levels of Populus hydrolysate medium (0% and 10% v/v), the PM showed both gene specific increases and decreases of gene expression compared to the wild-type strain. The PM had increased expression of genes in energy production and conversion, and amino acid transport and metabolism in both standard and 10% v/v Populus hydrolysate media. In particular, expression of the histidine metabolism increased up to 100 fold. In contrast, the PM decreased gene expression in cell division and sporulation (standard medium only), cell defense mechanisms, cell envelope, cell motility, and cellulosome in both media. The PM downregulated inorganic ion transport and metabolism in standard medium but upregulated it in the hydrolysate media when compared to the WT. The WT differentially expressed 1072 genes in response to the hydrolysate medium which included increased transcription of cell defense mechanisms, cell motility, and cellulosome, and decreased expression in cell envelope, amino acid transport and metabolism, inorganic ion transport and metabolism, and lipid metabolism, while the PM only differentially expressed 92 genes. The PM tolerates up to 17.5% v/v Populus hydrolysate and growth in it elicited 489 genes with differential expression, which included increased expression in energy production and conversion, cellulosome production, and inorganic ion transport and metabolism and decreased expression in transcription and cell

  12. Transcriptomic analysis of Clostridium thermocellum Populus hydrolysate-tolerant mutant strain shows increased cellular efficiency in response to Populus hydrolysate compared to the wild type strain.

    PubMed

    Linville, Jessica L; Rodriguez, Miguel; Brown, Steven D; Mielenz, Jonathan R; Cox, Chris D

    2014-08-16

    The thermophilic, anaerobic bacterium, Clostridium thermocellum is a model organism for consolidated processing due to its efficient fermentation of cellulose. Constituents of dilute acid pretreatment hydrolysate are known to inhibit C. thermocellum and other microorganisms. To evaluate the biological impact of this type of hydrolysate, a transcriptomic analysis of growth in hydrolysate-containing medium was conducted on 17.5% v/v Populus hydrolysate-tolerant mutant (PM) and wild type (WT) strains of C. thermocellum. In two levels of Populus hydrolysate medium (0% and 10% v/v), the PM showed both gene specific increases and decreases of gene expression compared to the wild-type strain. The PM had increased expression of genes in energy production and conversion, and amino acid transport and metabolism in both standard and 10% v/v Populus hydrolysate media. In particular, expression of the histidine metabolism increased up to 100 fold. In contrast, the PM decreased gene expression in cell division and sporulation (standard medium only), cell defense mechanisms, cell envelope, cell motility, and cellulosome in both media. The PM downregulated inorganic ion transport and metabolism in standard medium but upregulated it in the hydrolysate media when compared to the WT. The WT differentially expressed 1072 genes in response to the hydrolysate medium which included increased transcription of cell defense mechanisms, cell motility, and cellulosome, and decreased expression in cell envelope, amino acid transport and metabolism, inorganic ion transport and metabolism, and lipid metabolism, while the PM only differentially expressed 92 genes. The PM tolerates up to 17.5% v/v Populus hydrolysate and growth in it elicited 489 genes with differential expression, which included increased expression in energy production and conversion, cellulosome production, and inorganic ion transport and metabolism and decreased expression in transcription and cell defense mechanisms. These

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

    SciTech Connect

    Induri, Brahma R; Ellis, Danielle R; Slavov, Gancho; Yin, Tongming; Muchero, Wellington; Tuskan, Gerald A; DiFazio, Stephen P

    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.

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

    PubMed

    Tian, Feng-Xia; Zang, Jian-Lei; Wang, Tan; Xie, Yu-Li; Zhang, Jin; Hu, Jian-Jun

    2015-01-01

    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.

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

    SciTech Connect

    McKown, Athena; Klapste, Jaroslav; Guy, Robert; Geraldes, Armando; Porth, Ilga; Hannemann, Jan; Friedmann, Michael; Muchero, Wellington; Tuskan, Gerald A; Ehlting, Juergen; Cronk, Quentin; El-Kassaby, Yousry; Mansfield, Shawn; Douglas, Carl

    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).

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

    SciTech Connect

    Muchero, Wellington; Labbe, Jessy L; Priya, Ranjan; DiFazio, Steven P; Tuskan, Gerald A

    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.

  17. Productivity, water-use efficiency and tolerance to moderate water deficit correlate in 33 poplar genotypes from a Populus deltoides x Populus trichocarpa F1 progeny.

    PubMed

    Monclus, R; Villar, M; Barbaroux, C; Bastien, C; Fichot, R; Delmotte, F M; Delay, D; Petit, J-M; Bréchet, C; Dreyer, E; Brignolas, F

    2009-11-01

    Genotypic variability for productivity, water-use efficiency and leaf traits in 33 genotypes selected from an F1 progeny of Populus deltoides Bartr. ex Marsh x Populus trichocarpa L. was explored under optimal and moderate water-deficit conditions. Saplings of the 33 genotypes were grown in a two-plot open field at INRA Orléans (France) and coppiced every year. A moderate water deficit was induced during two successive years on one plot by withholding irrigation, while the second one remained irrigated (control). Stem biomass and leaf structure (e.g., specific leaf area and leaf area) were measured in 2004 and 2005 and functional leaf traits (e.g., carbon isotope discrimination, Delta) were measured only in 2004. Tolerance to water deficit was estimated at genotype level as the ability to limit losses in biomass production in water deficit versus control trees. Stem biomass, leaf structure and Delta displayed a significant genotypic variability whatever the irrigation regime. For all traits, genotype ranks remained stable across years for similar irrigation conditions. Carbon isotope discrimination scaled negatively with productivity and leaf nitrogen content in controls. The most productive genotypes were the least tolerant to moderate water deficit. No relationship was evidenced between Delta and the level of tolerance to water deficit. The relationships between traits evidenced in this collection of P. deltoides x P. trichocarpa F1 genotypes contrast with the ones that were previously detected in a collection of P. deltoides x Populus nigra L. cultivars tested in the same field trial.

  18. Microautoradiographic localization of phosphate and carbohydrates in mycorrhizal roots of Populus tremula x Populus alba and the implications for transfer processes in ectomycorrhizal associations.

    PubMed

    Bücking, H; Heyser, W

    2001-02-01

    Microautoradiographic studies were carried out to examine the distribution and exchange of phosphate and labeled carbohydrates in mycorrhizal roots of Populus tremula x Populus alba L. following application of 33P-orthophosphate (Pi) and 14CO2. Labeled Pi was not homogeneously distributed along the mycorrhizal longitudinal axis. The fungal sheath and the Hartig net contained more 33Pi in the median parts of the root than in the apical or basal root zones, indicating that uptake and transfer of Pi to the host plant was localized mainly in this area. The Pi was translocated by the Hartig net and the interfacial apoplast to the host plant. It was distributed by way of the stele within the plant. Young leaves and meristematic tissue in the shoot tip were the main sinks for Pi. In plants that were left in the dark for 5 days before 33Pi application, the reduced carbohydrate supply caused a decrease in Pi absorption by mycorrhizal roots. Microautoradiography of mycorrhizal roots after assimilation of 14CO2 revealed that: (1) the fungal partner had a high capacity to attract photosynthates; (2) the main transfer of carbohydrates was localized in the median zone of a mycorrhizal root; (3) carbohydrates that were absorbed by the mycorrhizal fungus were translocated to the fungal sheath and were homogeneously distributed; and (4) in the main exchange zone, cortical cell nuclei showed a high sink capacity, indicating increased metabolic activity in these cells. We postulate that (1) the phosphate demand of the host plant regulates absorption of Pi by the fungus, and (2) a bidirectional transfer of carbohydrates and Pi occurs across the same interface structure in ectomycorrhizal roots of Populus.

  19. Leaf-Induced Gibberellin Signaling Is Essential for Internode Elongation, Cambial Activity, and Fiber Differentiation in Tobacco Stems[C][W

    PubMed Central

    Dayan, Jonathan; Voronin, Nickolay; Gong, Fan; Sun, Tai-ping; Hedden, Peter; Fromm, Hillel; Aloni, Roni

    2012-01-01

    The gibberellins (GAs) are a group of endogenous compounds that promote the growth of most plant organs, including stem internodes. We show that in tobacco (Nicotiana tabacum) the presence of leaves is essential for the accumulation of bioactive GAs and their immediate precursors in the stem and consequently for normal stem elongation, cambial proliferation, and xylem fiber differentiation. These processes do not occur in the absence of maturing leaves but can be restored by application of C19-GAs, identifying the presence of leaves as a requirement for GA signaling in stems and revealing the fundamental role of GAs in secondary growth regulation. The use of reporter genes for GA activity and GA-directed DELLA protein degradation in Arabidopsis thaliana confirms the presence of a mobile signal from leaves to the stem that induces GA signaling. PMID:22253226

  20. A re-examination of the minor role of unstirred layers during the measurement of transport coefficients of Chara corallina internodes with the cell pressure probe.

    PubMed

    Ye, Qing; Kim, Yangmin; Steudle, Ernst

    2006-05-01

    The impact of unstirred layers (USLs) during cell pressure probe experiments with Chara corallina internodes has been quantified. The results show that the hydraulic conductivity (Lp) measured in hydrostatic relaxations was not significantly affected by USLs even in the presence of high water flow intensities ('sweep-away effect'). During pressure clamp, there was a reversible reduction in Lp by 20%, which was explained by the constriction of water to aquaporins (AQPs) in the C. corallina membrane and a rapid diffusional equilibration of solutes in arrays where water protruded across AQPs. In osmotic experiments, Lp, and permeability (Ps) and reflection (sigma s) coefficients increased as external flow rate of medium increased, indicating some effects of external USLs. However, the effect was levelling off at 'usual' flow rates of 0.20-0.30 m s(-1) and in the presence of vigorous stirring by air bubbles, suggesting a maximum thickness of external USLs of around 30 microm including the cell wall. Because the diameters of internodes were around 1 mm, internal USLs could have played a significant or even a dominating role, at least in the presence of the rapidly permeating solutes used [acetone, 2-propanol and dimethylformamide (DMF)]. A comparison of calculated (diffusion kinetics) and of measured permeabilities indicated an upper limit of the contribution of USLs for the rapidly moving solute acetone of 29%, and of 15% for the less rapidly permeating DME The results throw some doubt on recent claims that in C. corallina, USLs rather than the cell membrane dominate solute uptake, at least for the most rapidly moving solute acetone.

  1. Expression of a putative dioxygenase gene adjacent to an insertion mutation is involved in the short internodes of columnar apples (Malus × domestica).

    PubMed

    Okada, Kazuma; Wada, Masato; Moriya, Shigeki; Katayose, Yuichi; Fujisawa, Hiroko; Wu, Jianzhong; Kanamori, Hiroyuki; Kurita, Kanako; Sasaki, Harumi; Fujii, Hiroshi; Terakami, Shingo; Iwanami, Hiroshi; Yamamoto, Toshiya; Abe, Kazuyuki

    2016-11-01

    Determining the molecular mechanism of fruit tree architecture is important for tree management and fruit production. An apple mutant 'McIntosh Wijcik', which was discovered as a bud mutation from 'McIntosh', exhibits a columnar growth phenotype that is controlled by a single dominant gene, Co. In this study, the mutation and the Co gene were analyzed. Fine mapping narrowed the Co region to a 101 kb region. Sequence analysis of the Co region and the original wild-type co region identified an insertion mutation of an 8202 bp long terminal repeat (LTR) retroposon in the Co region. Segregation analysis using a DNA marker based on the insertion polymorphism showed that the LTR retroposon was closely associated with the columnar growth phenotype. RNA-seq and RT-PCR analysis identified a promising Co candidate gene (91071-gene) within the Co region that is specifically expressed in 'McIntosh Wijcik' but not in 'McIntosh'. The 91071-gene was located approximately 16 kb downstream of the insertion mutation and is predicted to encode a 2-oxoglutarate-dependent dioxygenase involved in an unknown reaction. Overexpression of the 91071-gene in transgenic tobaccos and apples resulted in phenotypes with short internodes, like columnar apples. These data suggested that the 8202 bp retroposon insertion in 'McIntosh Wijcik' is associated with the short internodes of the columnar growth phenotype via upregulated expression of the adjacent 91071-gene. Furthermore, the DNA marker based on the insertion polymorphism could be useful for the marker-assisted selection of columnar apples.

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

    SciTech Connect

    Tschaplinski, T.J.; Tuskan, G.A.; Wierman, C.

    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.

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

    SciTech Connect

    Tuskan, Gerald A; Gunter, Lee E; DiFazio, Stephen P

    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.

  4. Xylan hydrolysis in Populus trichocarpa × P. deltoides and model substrates during hydrothermal pretreatment.

    PubMed

    Trajano, Heather L; Pattathil, Sivakumar; Tomkins, Bruce A; Tschaplinski, Timothy J; Hahn, Michael G; Van Berkel, Gary J; Wyman, Charles E

    2015-03-01

    Previous studies defined easy and difficult to hydrolyze fractions of hemicellulose that may result from bonds among cellulose, hemicellulose, and lignin. To understand how such bonds affect hydrolysis, Populus trichocarpa × Populus deltoides, holocellulose isolated from P. trichocarpa × P. deltoides and birchwood xylan were subjected to hydrothermal flow-through pretreatment. Samples were characterized by glycome profiling, HPLC, and UPLC-MS. Glycome profiling revealed steady fragmentation and removal of glycans from solids during hydrolysis. The extent of polysaccharide fragmentation, hydrolysis rate, and total xylose yield were lowest for P. trichocarpa × P. deltoides and greatest for birchwood xylan. Comparison of results from P. trichocarpa × P. deltoides and holocellulose suggested that lignin-carbohydrate complexes reduce hydrolysis rates and limit release of large xylooligomers. Smaller differences between results with holocellulose and birchwood xylan suggest xylan-cellulose hydrogen bonds limited hydrolysis, but to a lesser extent. These findings imply cell wall structure strongly influences hydrolysis.

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

    PubMed

    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.

  6. Genome resequencing reveals multiscale geographic structure and extensive linkage disequilibrium in the forest tree Populus trichocarpa

    SciTech Connect

    Slavov, Gancho; DiFazio, Stephen P; Martin, Joel R; Schackwitz, Wendy; Muchero, Wellington; Rodgers-Melnick, Eli; Lipphardt, Mindie; Pennacchio, Christa; Hellsten, Uffe; Pennacchio, Len; Gunter, Lee; Ranjan, Priya; Strauss, Steven; Rokhsar, Daniel; Tuskan, Gerald A

    2012-01-01

    Population genomics of forest trees provides crucial information for breeding, conservation, and bioenergy feedstock development. As part of a large-scale association study, we resequenced 16 genomes of the model tree Populus trichocarpa to an average depth of 39 . Analyses of the resulting data revealed surprisingly extensive population genetic structure and decay of linkage disequilibrium over much larger physical distances than the expected based on previous, smaller-scale studies. Rates of recombination varied widely across the genome but were largely predictable based on DNA sequence and methylation patterns. Our results suggest that genomewide association studies and accurate prediction of phenotypes from DNA data are more feasible in Populus than previously assumed, thereby laying the foundation for a step change in our understanding of tree biology.

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

    PubMed

    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.

  8. Isolating a functionally relevant guild of fungi from the root microbiome of Populus

    SciTech Connect

    Bonito, Gregory; Hameed, Khalid; Ventura, Rafael; Krishnan, Jay; Schadt, Christopher W.; Vilgalys, Rytas

    2016-05-27

    Plant roots interact with a bewilderingly complex community of microbes, including root-associated fungi that are essential for maintaining plant health. To improve understanding of the diversity of fungi in the rhizobiome of Populus deltoides, Populus trichocarpa and co-occurring plant hosts Quercus alba and Pinus taeda, we conducted field and greenhouse studies and sampled, isolated, and characterized the diversity of culturable root-associated fungi on these hosts. Using both general and selective isolation media we obtained more than 1800 fungal isolates from individual surface sterilized root tips. Sequences from the ITS and/or D1– D2 regions of the LSU rDNA were obtained from 1042 of the >1800 pure culture isolates and were compared to accessions in the NCBI nucleotide database and analyzed through phylogenetics for preliminary taxonomic identification. Sequences from these isolates were also compared to 454 sequence datasets obtained directly from the Populus rhizosphere and endosphere. Although most of the ectomycorrhizal taxa known to associate with Populus evaded isolation, many of the abundant sequence types from rhizosphere and endosphere 454 datasets were isolated, including novel species belonging to the Atractiellales. Isolation and identification of key endorrhizal fungi will enable more targeted study of plant-fungal interactions. Genome sequencing is currently underway for a subset of our culture library with the aim of understanding the mechanisms involved in host-endophyte establishment and function. As a result, this diverse culture library of fungal root associates will be a valuable resource for metagenomic research, experimentation and further studies on plant-fungal interactions.

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

    Treesearch

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

    2009-01-01

    The 185-285 rDNA and 55 rDNA loci in Populus trichocarpa were localized using fluorescent in situ hybridization (FISH). Two 185-285 rDNA sites and one 55 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...

  10. Isolating a functionally relevant guild of fungi from the root microbiome of Populus

    SciTech Connect

    Bonito, Gregory; Hameed, Khalid; Ventura, Rafael; Krishnan, Jay; Schadt, Christopher W.; Vilgalys, Rytas

    2016-05-27

    Plant roots interact with a bewilderingly complex community of microbes, including root-associated fungi that are essential for maintaining plant health. To improve understanding of the diversity of fungi in the rhizobiome of Populus deltoides, Populus trichocarpa and co-occurring plant hosts Quercus alba and Pinus taeda, we conducted field and greenhouse studies and sampled, isolated, and characterized the diversity of culturable root-associated fungi on these hosts. Using both general and selective isolation media we obtained more than 1800 fungal isolates from individual surface sterilized root tips. Sequences from the ITS and/or D1– D2 regions of the LSU rDNA were obtained from 1042 of the >1800 pure culture isolates and were compared to accessions in the NCBI nucleotide database and analyzed through phylogenetics for preliminary taxonomic identification. Sequences from these isolates were also compared to 454 sequence datasets obtained directly from the Populus rhizosphere and endosphere. Although most of the ectomycorrhizal taxa known to associate with Populus evaded isolation, many of the abundant sequence types from rhizosphere and endosphere 454 datasets were isolated, including novel species belonging to the Atractiellales. Isolation and identification of key endorrhizal fungi will enable more targeted study of plant-fungal interactions. Genome sequencing is currently underway for a subset of our culture library with the aim of understanding the mechanisms involved in host-endophyte establishment and function. As a result, this diverse culture library of fungal root associates will be a valuable resource for metagenomic research, experimentation and further studies on plant-fungal interactions.

  11. Isolating a functionally relevant guild of fungi from the root microbiome of Populus

    DOE PAGES

    Bonito, Gregory; Hameed, Khalid; Ventura, Rafael; ...

    2016-05-27

    Plant roots interact with a bewilderingly complex community of microbes, including root-associated fungi that are essential for maintaining plant health. To improve understanding of the diversity of fungi in the rhizobiome of Populus deltoides, Populus trichocarpa and co-occurring plant hosts Quercus alba and Pinus taeda, we conducted field and greenhouse studies and sampled, isolated, and characterized the diversity of culturable root-associated fungi on these hosts. Using both general and selective isolation media we obtained more than 1800 fungal isolates from individual surface sterilized root tips. Sequences from the ITS and/or D1– D2 regions of the LSU rDNA were obtained frommore » 1042 of the >1800 pure culture isolates and were compared to accessions in the NCBI nucleotide database and analyzed through phylogenetics for preliminary taxonomic identification. Sequences from these isolates were also compared to 454 sequence datasets obtained directly from the Populus rhizosphere and endosphere. Although most of the ectomycorrhizal taxa known to associate with Populus evaded isolation, many of the abundant sequence types from rhizosphere and endosphere 454 datasets were isolated, including novel species belonging to the Atractiellales. Isolation and identification of key endorrhizal fungi will enable more targeted study of plant-fungal interactions. Genome sequencing is currently underway for a subset of our culture library with the aim of understanding the mechanisms involved in host-endophyte establishment and function. As a result, this diverse culture library of fungal root associates will be a valuable resource for metagenomic research, experimentation and further studies on plant-fungal interactions.« less

  12. Intra-annual growth and mortality of four Populus clones in pure and mixed plantings

    Treesearch

    Warren D. Devine; Constance A. Harrington; Dean S. DeBell

    2010-01-01

    Intra-annual growth rates were assessed during 3 years for four Populus clones grown in pure and mixed clonal stands at square spacings of 0.5, 1.0, and 1.5 m in western Washington, USA. Height growth rate peaked in August, except at the 0.5-m spacing where it peaked in July and June in years 2 and 3, respectively. Diameter growth rate generally...

  13. Genetic analysis of post-mating reproductive barriers in hybridizing European Populus species

    PubMed Central

    Macaya-Sanz, D; Suter, L; Joseph, J; Barbará, T; Alba, N; González-Martínez, S C; Widmer, A; Lexer, C

    2011-01-01

    Molecular genetic analyses of experimental crosses provide important information on the strength and nature of post-mating barriers to gene exchange between divergent populations, which are topics of great interest to evolutionary geneticists and breeders. Although not a trivial task in long-lived organisms such as trees, experimental interspecific recombinants can sometimes be created through controlled crosses involving natural F1's. Here, we used this approach to understand the genetics of post-mating isolation and barriers to introgression in Populus alba and Populus tremula, two ecologically divergent, hybridizing forest trees. We studied 86 interspecific backcross (BC1) progeny and >350 individuals from natural populations of these species for up to 98 nuclear genetic markers, including microsatellites, indels and single nucleotide polymorphisms, and inferred the origin of the cytoplasm of the cross with plastid DNA. Genetic analysis of the BC1 revealed extensive segregation distortions on six chromosomes, and >90% of these (12 out of 13) favored P. tremula donor alleles in the heterospecific genomic background. Since selection was documented during early diploid stages of the progeny, this surprising result was attributed to epistasis, cyto-nuclear coadaptation, heterozygote advantage at nuclear loci experiencing introgression or a combination of these. Our results indicate that gene flow across ‘porous' species barriers affects these poplars and aspens beyond neutral, Mendelian expectations and suggests the mechanisms responsible. Contrary to expectations, the Populus sex determination region is not protected from introgression. Understanding the population dynamics of the Populus sex determination region will require tests based on natural interspecific hybrid zones. PMID:21587301

  14. Carbon allocation and nitrogen acquisition in a developing Populus deltoides plantation

    Treesearch

    Mark D. Coleman; Alexander L. Friend; Christel C. Kern

    2004-01-01

    We established Populus deltoides Bartr. stands differing in nitrogen (N) availability and tested if: (1) N-induced carbon (C) allocation could be explained by develop- mental allocation controls; and (2) N uptake per unit root mass, i.e., specific N-uptake rate, increased with N availability. Closely spaced (1 × 1 m) stands were treated with 50, 100 and 200 kg N ha ­...

  15. Patterns of interaction between Populus Esch5 and Piriformospora indica: a transition from mutualism to antagonism.

    PubMed

    Kaldorf, M; Koch, B; Rexer, K-H; Kost, G; Varma, A

    2005-03-01

    Piriformospora indica (Sebacinaceae, Basidiomycota) is an axenically cultivable, plant growth promoting root endophyte with a wide host range, including Populus. Rooting of Populus Esch5 explants started within 6 days after transfer to WPM medium. If such plantlets with roots were inoculated with P. indica, there was an increase in root biomass, and the number of 2nd order roots was increased significantly. A totally different observation was recorded when the explants were placed into WPM with pre-grown P. indica. The interaction led to complete blocking of root production and severely inhibited plant growth. Additionally, branched aerial roots appeared which did not penetrate the medium. On contact with the fungal colony or the medium, the ends of the aerial roots became inflated. Prolonged incubation stimulated the fungus to colonize aerial parts of the plant (stem and leaves). Mycelium not only spread on the surface of the aerial parts, but also invaded the cortical tissues inter- and intracellularly. Detached Populus leaves remained vital for 4 - 5 weeks on sterile agar media or on AspM medium with pre-grown P. indica. When the fungus was pre-grown on culture media such as WPM, containing ammonium as the main source of nitrogen, leaves in contact with the cultures turned brownish within 4 - 12 h. Thereafter, the leaves bleached, and about one day later had become whitish. Thus, cultural conditions could alter the behaviour of the fungus drastically: the outcome of the interaction between plant and fungus can be directed from mutualistic to antagonistic, characterized by fungal toxin formation and extension of the colonization to Populus shoots.

  16. Dendrochronological and palynological observations on Populus balsamifera in northern Alaska, USA

    SciTech Connect

    Edwards, M.E.; Dunwiddie, P.W.

    1985-01-01

    Sexual and clonal reproduction is occurring in a stand of Populus balsamifera on the Alaskan North Slope. Both even-aged and gradually expanding clones were observed. Trees attain ages in excess of 230 yr, but are slender due to slow diametrical growth (1.4 to 2.5 mm yr/sup -1/). A tree-ring chronology developed using 16 trees exhibited higher mean sensitivity (0.48) and lower first-order autocorrelation (0.43) than other high-latitude chronologies. Ring-width indices were most highly correlated with June temperature (r = 0.50). This species may be useful in expanding the array of climatically sensitive tree-ring sites in the Arctic. Moss polster samples in the vicinity of the stand indicate that although abundant Populus pollen is produced, little is found in surface samples > 30 m from the trees. It is suggested that Populus balsamifera was considerably more abundant in Beringia during the early Holocene due to warm early summer temperatures and widespread substrates favorable for its growth.

  17. Polyphenol oxidase overexpression in transgenic Populus enhances resistance to herbivory by forest tent caterpillar (Malacosoma disstria).

    PubMed

    Wang, Jiehua; Constabel, C Peter

    2004-11-01

    In order to functionally analyze the predicted defensive role of leaf polyphenol oxidase (PPO; EC 1.10.3.1) in Populus, transgenic hybrid aspen (Populus tremula x P. alba) plants overexpressing a hybrid poplar (Populus trichocarpa x P. deltoides) PtdPPO1 gene were constructed. Regenerated transgenic plants showed high PPO enzyme activity, PtdPPO1 mRNA levels and PPO protein accumulation. In leaf disk bioassays, forest tent caterpillar (Malacosoma disstria) larvae feeding on PPO-overexpressing transgenics experienced significantly higher mortality and reduced average weight gain compared to larvae feeding on control leaves. However, this effect was observed only when older egg masses were used and the resulting larvae showed reduced growth and vigor. In choice tests, no effect of PPO overexpression was detected. Although PPO in poplar leaves is latent and requires activation with detergents or trypsin for full enzymatic activity, in caterpillar frass the enzyme was extracted in the fully activated form. This activation correlated with partial proteolytic cleavage, suggesting that PPO latency and activation during digestion could be an adaptive and defense-related feature of poplar PPO.

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

    SciTech Connect

    Payyavula, Raja S.; Tschaplinski, Timothy J.; Jawdy, Sara; Sykes, Robert; Tuskan, Gerald A.; Kalluri, Udaya C.

    2014-10-07

    Background: UDP-glucose pyrophopharylase (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 uridine triphosphate glucose. UDP-glucose is a key intermediate sugar that is channeled to multiple metabolic pathways. The functional role of UGPase in woody plants such as Populus is poorly understood. Results: We characterized the functional role of UGPase in Populus deltoides by overexpressing a native gene. Overexpression of the native gene resulted in increased leaf area and leaf-to-shoot biomass ratio but decreased shoot and root growth. Metabolomic analyses showed that manipulation of UGPase results in perturbations in primary as well as secondary metabolism resulting in reduced sugar and starch levels and increased phenolics such as caffeoyl- and feruloyl conjugates. While cellulose and lignin levels in the cell walls were not significantly altered, the syringyl-to-guaiacyl ratio was significantly reduced. Conclusions: These results demonstrate that UGPase plays a key role in the tightly coupled primary and secondary metabolic pathways and perturbation in its function results in pronounced effects on growth and metabolism outside of cell wall biosynthesis of Populus.

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

    DOE PAGES

    Payyavula, Raja S.; Tschaplinski, Timothy J.; Jawdy, Sara; ...

    2014-10-07

    Background: UDP-glucose pyrophopharylase (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 uridine triphosphate glucose. UDP-glucose is a key intermediate sugar that is channeled to multiple metabolic pathways. The functional role of UGPase in woody plants such as Populus is poorly understood. Results: We characterized the functional role of UGPase in Populus deltoides by overexpressing a native gene. Overexpression of the native gene resulted in increased leaf area and leaf-to-shoot biomass ratio but decreased shoot and root growth. Metabolomic analyses showed that manipulation of UGPase results in perturbations inmore » primary as well as secondary metabolism resulting in reduced sugar and starch levels and increased phenolics such as caffeoyl- and feruloyl conjugates. While cellulose and lignin levels in the cell walls were not significantly altered, the syringyl-to-guaiacyl ratio was significantly reduced. Conclusions: These results demonstrate that UGPase plays a key role in the tightly coupled primary and secondary metabolic pathways and perturbation in its function results in pronounced effects on growth and metabolism outside of cell wall biosynthesis of Populus.« less

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

    NASA Astrophysics Data System (ADS)

    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.

  1. Genome-Wide Identification of the Invertase Gene Family in Populus.

    PubMed

    Chen, Zhong; Gao, Kai; Su, Xiaoxing; Rao, Pian; An, Xinmin

    2015-01-01

    Invertase plays a crucial role in carbohydrate partitioning and plant development as it catalyses the irreversible hydrolysis of sucrose into glucose and fructose. The invertase family in plants is composed of two sub-families: acid invertases, which are targeted to the cell wall and vacuole; and neutral/alkaline invertases, which function in the cytosol. In this study, 5 cell wall invertase genes (PtCWINV1-5), 3 vacuolar invertase genes (PtVINV1-3) and 16 neutral/alkaline invertase genes (PtNINV1-16) were identified in the Populus genome and found to be distributed on 14 chromosomes. A comprehensive analysis of poplar invertase genes was performed, including structures, chromosome location, phylogeny, evolutionary pattern and expression profiles. Phylogenetic analysis indicated that the two sub-families were both divided into two clades. Segmental duplication is contributed to neutral/alkaline sub-family expansion. Furthermore, the Populus invertase genes displayed differential expression in roots, stems, leaves, leaf buds and in response to salt/cold stress and pathogen infection. In addition, the analysis of enzyme activity and sugar content revealed that invertase genes play key roles in the sucrose metabolism of various tissues and organs in poplar. This work lays the foundation for future functional analysis of the invertase genes in Populus and other woody perennials.

  2. Genome-Wide Identification of the Invertase Gene Family in Populus

    PubMed Central

    Su, Xiaoxing; Rao, Pian; An, Xinmin

    2015-01-01

    Invertase plays a crucial role in carbohydrate partitioning and plant development as it catalyses the irreversible hydrolysis of sucrose into glucose and fructose. The invertase family in plants is composed of two sub-families: acid invertases, which are targeted to the cell wall and vacuole; and neutral/alkaline invertases, which function in the cytosol. In this study, 5 cell wall invertase genes (PtCWINV1-5), 3 vacuolar invertase genes (PtVINV1-3) and 16 neutral/alkaline invertase genes (PtNINV1-16) were identified in the Populus genome and found to be distributed on 14 chromosomes. A comprehensive analysis of poplar invertase genes was performed, including structures, chromosome location, phylogeny, evolutionary pattern and expression profiles. Phylogenetic analysis indicated that the two sub-families were both divided into two clades. Segmental duplication is contributed to neutral/alkaline sub-family expansion. Furthermore, the Populus invertase genes displayed differential expression in roots, stems, leaves, leaf buds and in response to salt/cold stress and pathogen infection. In addition, the analysis of enzyme activity and sugar content revealed that invertase genes play key roles in the sucrose metabolism of various tissues and organs in poplar. This work lays the foundation for future functional analysis of the invertase genes in Populus and other woody perennials. PMID:26393355

  3. Genome resequencing reveals multiscale geographic structure and extensive linkage disequilibrium in the forest tree Populus trichocarpa.

    PubMed

    Slavov, Gancho T; DiFazio, Stephen P; Martin, Joel; Schackwitz, Wendy; Muchero, Wellington; Rodgers-Melnick, Eli; Lipphardt, Mindie F; Pennacchio, Christa P; Hellsten, Uffe; Pennacchio, Len A; Gunter, Lee E; Ranjan, Priya; Vining, Kelly; Pomraning, Kyle R; Wilhelm, Larry J; Pellegrini, Matteo; Mockler, Todd C; Freitag, Michael; Geraldes, Armando; El-Kassaby, Yousry A; Mansfield, Shawn D; Cronk, Quentin C B; Douglas, Carl J; Strauss, Steven H; Rokhsar, Dan; Tuskan, Gerald A

    2012-11-01

    • Plant population genomics informs evolutionary biology, breeding, conservation and bioenergy feedstock development. For example, the detection of reliable phenotype-genotype associations and molecular signatures of selection requires a detailed knowledge about genome-wide patterns of allele frequency variation, linkage disequilibrium and recombination. • We resequenced 16 genomes of the model tree Populus trichocarpa and genotyped 120 trees from 10 subpopulations using 29,213 single-nucleotide polymorphisms. • Significant geographic differentiation was present at multiple spatial scales, and range-wide latitudinal allele frequency gradients were strikingly common across the genome. The decay of linkage disequilibrium with physical distance was slower than expected from previous studies in Populus, with r(2) dropping below 0.2 within 3-6 kb. Consistent with this, estimates of recent effective population size from linkage disequilibrium (N(e) ≈ 4000-6000) were remarkably low relative to the large census sizes of P. trichocarpa stands. Fine-scale rates of recombination varied widely across the genome, but were largely predictable on the basis of DNA sequence and methylation features. • Our results suggest that genetic drift has played a significant role in the recent evolutionary history of P. trichocarpa. Most importantly, the extensive linkage disequilibrium detected suggests that genome-wide association studies and genomic selection in undomesticated populations may be more feasible in Populus than previously assumed. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  4. The SUPERMAN gene family in Populus: nucleotide diversity and gene expression in a dioecious plant.

    PubMed

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

    2013-08-01

    SUP gene family expression and regulation patterns reported in dioecious woody plant. Phylogenetic and nucleotide diversity analysis indicated PtoSUP1 is highly conserved and has undergone strong purifying selection. The molecular basis of SUPERMAN (SUP) regulation during floral development in monoecious plants has been extensively studied, but little is known of the SUP gene family in dioecious woody plants. In this study, we systematically examined the diversification of the SUP gene family in Populus, integrating genomic organization, expression, and phylogeny data. SUP family members showed sex-specific expression throughout flower development. Transcript profiling of rare gynomonoecious poplar flowers revealed that a significant reduction in PtoSUP1 mRNA might be important for stamen development in gynomonoecious poplar flowers. We found that the coding regions of Populus SUP genes are very highly conserved and that synonymous sites in exon regions have undergone strong purifying selection during SUP evolution in Populus. These results indicate that SUP genes play an important role in floral development of dioecious plants. Expression analysis of SUP suggested possible regulatory mechanisms for gynomonoecious poplar flower development. These findings provide an important insight into the mechanisms of the evolution of SUP function and may help enable engineered regulation of flower development for breeding improved tree varieties.

  5. [Effects of cadmium stress on the microbial biodiversity in purple soil and alluvial soil potted with a poplar (Populus deltoides x Populus nigra)].

    PubMed

    Wang, Ao; Wu, Fu-Zhong; Yang, Wan-Qin; Zhou, Li-Qiang; Wang, Xu-Xi; Han, Yu

    2011-07-01

    Effects of current Cd contamination levels on microbial biodiversity were studied under the typical Cd contaminated soils in the Yangtze Basin. Purple soil and alluvial soil potted with a poplar (Populus deltoides x Populus nigra) were selected, and the culturable soil microbial amounts by flat method, microbial biomass and bacterial community structure by PCR-DGGE were investigated. Cd supplies significantly increased the culturable amounts of bacteria and actinomyces in purple soil, but decreased the culturable amounts of fungi and the content of microbial biomass N. Fingerprint of DGGE also showed that bacterial community structure have obviously changed under different Cd supplies. In contrast, the lower Cd supplies slightly increased the culturable amounts of bacteria and fungi in alluvial soil, but higher Cd supply treatment decreased the culturable amounts of bacteria, actinomyces and fungi, and the content of microbial biomass N. However, only a slight change was observed under different Cd supplies by DGGE fingerprint. Additionally, there were few effects of Cd supplies on the content of microbial biomass C in both purple soil and alluvial soil. The results provided basic data to understand the effects of present Cd contamination levels on soil microbial characteristics.

  6. Common trade-offs between xylem resistance to cavitation and other physiological traits do not hold among unrelated Populus deltoides x Populus nigra hybrids.

    PubMed

    Fichot, Régis; Barigah, Têtè S; Chamaillard, Sylvain; LE Thiec, Dider; Laurans, Françoise; Cochard, Hervé; Brignolas, Franck

    2010-09-01

    We examined the relationships between xylem resistance to cavitation and 16 structural and functional traits across eight unrelated Populus deltoides x Populus nigra genotypes grown under two contrasting water regimes. The xylem water potential inducing 50% loss of hydraulic conductance (Psi(50)) varied from -1.60 to -2.40 MPa. Drought-acclimated trees displayed a safer xylem, although the extent of the response was largely genotype dependent, with Psi(50) being decreased by as far as 0.60 MPa. At the tissue level, there was no clear relationship between xylem safety and either xylem water transport efficiency or xylem biomechanics; the only structural trait to be strongly associated with Psi(50) was the double vessel wall thickness, genotypes exhibiting a thicker double wall being more resistant. At the leaf level, increased cavitation resistance was associated with decreased stomatal conductance, while no relationship could be identified with traits associated with carbon uptake or bulk leaf carbon isotope discrimination, a surrogate of intrinsic water-use efficiency. At the whole-plant level, increased safety was associated with higher shoot growth potential under well-irrigated regime only. We conclude that common trade-offs between xylem resistance to cavitation and other physiological traits that are observed across species may not necessarily hold true at narrower scales.

  7. Immunohistochemical localization of enzymes that catalyze the long sequential pathways of lignin biosynthesis during differentiation of secondary xylem tissues of hybrid aspen (Populus sieboldii x Populus grandidentata).

    PubMed

    Sato, Kanna; Nishikubo, Nobuyuki; Mashino, Yoko; Yoshitomi, Kaori; Zhou, Jinmei; Kajita, Shinya; Katayama, Yoshihiro

    2009-12-01

    We have investigated the spatial localization of enzymes that catalyze the sequential pathways of lignin biosynthesis in developing secondary xylem tissues of hybrid aspen (Populus sieboldii Miq. x Populus grandidentata Michx.) using immunohistochemical techniques. The enzymes phenylalanine ammonia-lyase, caffeic acid 3-O-methyltransferase and 4-coumarate:CoA ligase in the common phenylpropanoid pathway, cinnamyl-alcohol dehydrogenase (CAD) and peroxidase in the specific lignin pathway, 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase (DAHPS) in the shikimate pathway and glutamine synthetase (GS) in the nitrogen reassimilation system were abundantly localized in the 6th to 9th wood fibers away from cambium; these wood fibers are likely undergoing the most intense lignification. Only weak immunolabeling of enzymes involved in the general phenylpropanoid and specific lignin pathways was detected in the cells near the cambium; lignification of these cells has likely been initiated after primary cell wall formation. In contrast, distinct localization of DAHPS and GS was observed around the cambium, which may be involved not only in lignin biosynthesis, but also in amino acid and protein synthesis, which are essential for cell survival. Our observations suggest that co-localization of enzymes related to the sequential shikimate, general phenylpropanoid and specific lignin branch pathways and to the nitrogen recycling system is associated with cell wall lignification of wood fibers during secondary xylem development.

  8. Rapid Activation of Phenylpropanoid Metabolism in Elicitor-Treated Hybrid Poplar (Populus trichocarpa Torr. & Gray × Populus deltoides Marsh) Suspension-Cultured Cells 1

    PubMed Central

    de Sá, Mário Moniz; Subramaniam, Rajgopal; Williams, Frank E.; Douglas, Carl J.

    1992-01-01

    Elicitor induction of phenylpropanoid metabolism was investigated in suspension-cultured cells of the fast-growing poplar hybrid (Populus trichocarpa Torr. & Gray × Populus deltoides Marsh) H11-11. Treatment of cells with polygalacturonic acid lyase or two fungal elicitors resulted in rapid and transient increases in extractable l-phenylalanine ammonia lyase and 4-coumarate:coenzyme A ligase enzyme activities. The substrate specificity of the inducible 4-coumarate:coenzyme A ligase enzyme activity appeared to differ from substrate specificity of 4-coumarate:coenzyme A ligase enzyme activity in untreated control cells. Large and transient increases in the accumulation of l-phenylalanine ammonia-lyase and 4-coumarate:coenzyme A ligase mRNAs preceded the increases in enzyme activities and were detectable by 30 minutes after the start of elicitor treatment. Chalcone synthase, cinnamyl alcohol dehydrogenase, and coniferin β-glucosidase enzyme activities were unaffected by the elicitors, but a large and transient increase in β-glucosidase activity capable of hydrolyzing 4-nitrophenyl-β-glucoside was observed. Subsequent to increases in l-phenylalanine ammonialyase and 4-coumarate:coenzyme A ligase enzyme activities, cell wall-bound thioglycolic acid-extractable compounds accumulated in elicitor-treated cultures, and these cells exhibited strong staining with phloroglucinol, suggesting the accumulation of wall-bound phenolic compounds. ImagesFigure 7Figure 9 PMID:16668702

  9. Expression divergence of cellulose synthase (CesA) genes after a recent whole genome duplication event in Populus.

    PubMed

    Takata, Naoki; Taniguchi, Toru

    2015-01-01

    Secondary cell wall-associated CesA genes in Populus have undergone a functional differentiation in expression pattern that may be attributable to evolutionary alteration of regulatory modules. Gene duplication is an important mechanism for functional divergence of genes. Secondary cell wall-associated cellulose synthase genes (CesA4, CesA7 and CesA8) are duplicated in Populus plants due to a recent whole genome duplication event. Here, we demonstrate that duplicate CesA genes show tissue-dependent expression divergence in Populus plants. Real-time PCR analysis of Populus CesA genes suggested that Pt × tCesA8-B was more highly expressed than Pt × tCesA8-A in phloem and secondary xylem tissue of mature stem. Histochemical and histological analyses of transformants expressing a GFP-GUS fusion gene driven by Populus CesA promoters revealed that the duplicate CesA genes showed different expression patterns in phloem fibers, secondary xylem, root cap and leaf trichomes. We predicted putative cis-regulatory motifs that regulate expression of secondary cell wall-associated CesA genes, and identified 19 motifs that are highly conserved in the CesA gene family of eudicotyledonous plants. Furthermore, a transient transactivation assay identified candidate transcription factors that affect levels and patterns of expression of Populus CesA genes. The present study reveals that secondary cell wall-associated CesA genes in Populus have undergone a functional differentiation in expression pattern that may be attributable to evolutionary alteration of regulatory modules.

  10. Expansion and diversification of the SET domain gene family following whole-genome duplications in Populus trichocarpa

    PubMed Central

    2012-01-01

    Background Histone lysine methylation modifies chromatin structure and regulates eukaryotic gene transcription and a variety of developmental and physiological processes. SET domain proteins are lysine methyltransferases containing the evolutionarily-conserved SET domain, which is known to be the catalytic domain. Results We identified 59 SET genes in the Populus genome. Phylogenetic analyses of 106 SET genes from Populus and Arabidopsis supported the clustering of SET genes into six distinct subfamilies and identified 19 duplicated gene pairs in Populus. The chromosome locations of these gene pairs and the distribution of synonymous substitution rates showed that the expansion of the SET gene family might be caused by large-scale duplications in Populus. Comparison of gene structures and domain architectures of each duplicate pair indicated that divergence took place at the 3'- and 5'-terminal transcribed regions and at the N- and C-termini of the predicted proteins, respectively. Expression profile analysis of Populus SET genes suggested that most Populus SET genes were expressed widely, many with the highest expression in young leaves. In particular, the expression profiles of 12 of the 19 duplicated gene pairs fell into two types of expression patterns. Conclusions The 19 duplicated SET genes could have originated from whole genome duplication events. The differences in SET gene structure, domain architecture, and expression profiles in various tissues of Populus suggest that members of the SET gene family have a variety of developmental and physiological functions. Our study provides clues about the evolution of epigenetic regulation of chromatin structure and gene expression. PMID:22497662

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

    PubMed Central

    2013-01-01

    Background 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. Results 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. Conclusion 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

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

    PubMed

    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

  13. Genome-wide identification, classification, and expression analysis of CDPK and its closely related gene families in poplar (Populus trichocarpa).

    PubMed

    Zuo, Ran; Hu, Ruibo; Chai, Guohua; Xu, Meiling; Qi, Guang; Kong, Yingzhen; Zhou, Gongke

    2013-03-01

    Calcium-dependent protein kinases (CDPKs) are Ca(2+)-binding proteins known to play crucial roles in Ca(2+) signal transduction pathways which have been identified throughout plant kingdom and in certain types of protists. Genome-wide analysis of CDPKs have been carried out in Arabidopsis, rice and wheat, and quite a few of CDPKs were proved to play crucial roles in plant stress responsive signature pathways. In this study, a comprehensive analysis of Populus CDPK and its closely related gene families was performed, including phylogeny, chromosome locations, gene structures, and expression profiles. Thirty Populus CDPK genes and twenty closely related kinase genes were identified, which were phylogenetically clustered into eight distinct subfamilies and predominately distributed across fifteen linkage groups (LG). Genomic organization analyses indicated that purifying selection has played a pivotal role in the retention and maintenance of Populus CDPK gene family. Furthermore, microarray analysis showed that a number of Populus CDPK and its closely related genes differentially expressed across disparate tissues and under various stresses. The expression profiles of paralogous pairs were also investigated to reveal their evolution fates. In addition, quantitative real-time RT-PCR was performed on nine selected CDPK genes to confirm their responses to drought stress treatment. These observations may lay the foundation for future functional analysis of Populus CDPK and its closely related gene families to unravel their biological roles.

  14. Differentiation of Populus species using chloroplast single nucleotide polymorphism (SNP) markers--essential for comprehensible and reliable poplar breeding.

    PubMed

    Schroeder, H; Hoeltken, A M; Fladung, M

    2012-03-01

    Within the genus Populus several species belonging to different sections are cross-compatible. Hence, high numbers of interspecies hybrids occur naturally and, additionally, have been artificially produced in huge breeding programmes during the last 100 years. Therefore, determination of a single poplar species, used for the production of 'multi-species hybrids' is often difficult, and represents a great challenge for the use of molecular markers in species identification. Within this study, over 20 chloroplast regions, both intergenic spacers and coding regions, have been tested for their ability to differentiate different poplar species using 23 already published barcoding primer combinations and 17 newly designed primer combinations. About half of the published barcoding primers yielded amplification products, whereas the new primers designed on the basis of the total sequenced cpDNA genome of Populus trichocarpa Torr. & Gray yielded much higher amplification success. Intergenic spacers were found to be more variable than coding regions within the genus Populus. The highest discrimination power of Populus species was found in the combination of two intergenic spacers (trnG-psbK, psbK-psbl) and the coding region rpoC. In barcoding projects, the coding regions matK and rbcL are often recommended, but within the genus Populus they only show moderate variability and are not efficient in species discrimination.

  15. Twenty-One Genome Sequences from Pseudomonas Species and 19 Genome Sequences from Diverse Bacteria Isolated from the Rhizosphere and Endosphere of Populus deltoides

    SciTech Connect

    Brown, Steven D; Utturkar, Sagar M; Klingeman, Dawn Marie; Johnson, Courtney M; Martin, Stanton; Land, Miriam L; Lu, Tse-Yuan; Schadt, Christopher Warren; Doktycz, Mitchel John; Pelletier, Dale A

    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.

  16. Economic injury level for second-generation cottonwood leaf beetle (Coleoptera: Chrysomelidae) in two-year-old Populus.

    PubMed

    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.

  17. Diversification and Expression of the PIN, AUX/LAX, and ABCB Families of Putative Auxin Transporters in Populus

    PubMed Central

    Carraro, Nicola; Tisdale-Orr, Tracy Eizabeth; Clouse, Ronald Matthew; Knöller, Anne Sophie; Spicer, Rachel

    2012-01-01

    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 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 gene 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 genes involved in this process. This work should lay the foundation for studies targeting specific proteins for functional characterization and in situ localization. PMID:22645571

  18. Screening of rice mutants with improved saccharification efficiency results in the identification of CONSTITUTIVE PHOTOMORPHOGENIC 1 and GOLD HULL AND INTERNODE 1.

    PubMed

    Hirano, Ko; Masuda, Reiko; Takase, Wakana; Morinaka, Yoichi; Kawamura, Mayuko; Takeuchi, Yoshinobu; Takagi, Hiroki; Yaegashi, Hiroki; Natsume, Satoshi; Terauchi, Ryohei; Kotake, Toshihisa; Matsushita, Yasuyuki; Sazuka, Takashi

    2017-07-01

    The screening of rice mutants with improved cellulose to glucose saccharification efficiency (SE) identifies reduced xylan and/or ferulic acid, and a qualitative change of lignin to impact SE. To ensure the availability of sustainable energy, considerable effort is underway to utilize lignocellulosic plant biomass as feedstock for the production of biofuels. However, the high cost of degrading plant cell wall components to fermentable sugars (saccharification) has been problematic. One way to overcome this barrier is to develop plants possessing cell walls that are amenable to saccharification. In this study, we aimed to identify new molecular factors that influence saccharification efficiency (SE) in rice. By screening 22 rice mutants, we identified two lines, 122 and 108, with improved SE. Reduced xylan and ferulic acid within the cell wall of line 122 were probable reasons of improved SE. Line 108 showed reduced levels of thioglycolic-released lignin; however, the amount of Klason lignin was comparable to the wild-type, indicating that structural changes had occurred in the 108 lignin polymer which resulted in improved SE. Positional cloning revealed that the genes responsible for improved SE in 122 and 108 were rice CONSTITUTIVE PHOTOMORPHOGENIC 1 (OsCOP1) and GOLD HULL AND INTERNODE 1 (GH1), respectively, which have not been previously reported to influence SE. The screening of mutants for improved SE is an efficient approach to identify novel genes that affect SE, which is relevant in the development of crops as biofuel sources.

  19. A Homolog of Blade-On-Petiole 1 and 2 (BOP1/2) Controls Internode Length and Homeotic Changes of the Barley Inflorescence.

    PubMed

    Jost, Matthias; Taketa, Shin; Mascher, Martin; Himmelbach, Axel; Yuo, Takahisa; Shahinnia, Fahimeh; Rutten, Twan; Druka, Arnis; Schmutzer, Thomas; Steuernagel, Burkhard; Beier, Sebastian; Taudien, Stefan; Scholz, Uwe; Morgante, Michele; Waugh, Robbie; Stein, Nils

    2016-06-01

    Inflorescence architecture in small-grain cereals has a direct effect on yield and is an important selection target in breeding for yield improvement. We analyzed the recessive mutation laxatum-a (lax-a) in barley (Hordeum vulgare), which causes pleiotropic changes in spike development, resulting in (1) extended rachis internodes conferring a more relaxed inflorescence, (2) broadened base of the lemma awns, (3) thinner grains that are largely exposed due to reduced marginal growth of the palea and lemma, and (4) and homeotic conversion of lodicules into two stamenoid structures. Map-based cloning enforced by mapping-by-sequencing of the mutant lax-a locus enabled the identification of a homolog of BLADE-ON-PETIOLE1 (BOP1) and BOP2 as the causal gene. Interestingly, the recently identified barley uniculme4 gene also is a BOP1/2 homolog and has been shown to regulate tillering and leaf sheath development. While the Arabidopsis (Arabidopsis thaliana) BOP1 and BOP2 genes act redundantly, the barley genes contribute independent effects in specifying the developmental growth of vegetative and reproductive organs, respectively. Analysis of natural genetic diversity revealed strikingly different haplotype diversity for the two paralogous barley genes, likely affected by the respective genomic environments, since no indication for an active selection process was detected. © 2016 American Society of Plant Biologists. All Rights Reserved.

  20. A Homolog of Blade-On-Petiole 1 and 2 (BOP1/2) Controls Internode Length and Homeotic Changes of the Barley Inflorescence1[OPEN

    PubMed Central

    Taketa, Shin; Mascher, Martin; Yuo, Takahisa; Beier, Sebastian; Taudien, Stefan; Morgante, Michele

    2016-01-01

    Inflorescence architecture in small-grain cereals has a direct effect on yield and is an important selection target in breeding for yield improvement. We analyzed the recessive mutation laxatum-a (lax-a) in barley (Hordeum vulgare), which causes pleiotropic changes in spike development, resulting in (1) extended rachis internodes conferring a more relaxed inflorescence, (2) broadened base of the lemma awns, (3) thinner grains that are largely exposed due to reduced marginal growth of the palea and lemma, and (4) and homeotic conversion of lodicules into two stamenoid structures. Map-based cloning enforced by mapping-by-sequencing of the mutant lax-a locus enabled the identification of a homolog of BLADE-ON-PETIOLE1 (BOP1) and BOP2 as the causal gene. Interestingly, the recently identified barley uniculme4 gene also is a BOP1/2 homolog and has been shown to regulate tillering and leaf sheath development. While the Arabidopsis (Arabidopsis thaliana) BOP1 and BOP2 genes act redundantly, the barley genes contribute independent effects in specifying the developmental growth of vegetative and reproductive organs, respectively. Analysis of natural genetic diversity revealed strikingly different haplotype diversity for the two paralogous barley genes, likely affected by the respective genomic environments, since no indication for an active selection process was detected. PMID:27208226

  1. Actin-dependent deposition of putative endosomes and of endoplasmic reticulum during early stages of wound healing in characean internodal cells

    PubMed Central

    Klima, A.; Foissner, I.

    2012-01-01

    We investigated the behaviour of organelles stained by FM1-43 (putative endosomes) and/or LysoTracker Red (LTred; acidic compartments) and that of the endoplasmic reticulum (ER) during healing of puncture and UV-induced wounds in internodal cells of Nitella flexilis and Chara corallina. Immediately after puncturing, wounds were passively sealed by a plug of solid vacuolar inclusions onto which a bipartite wound wall was actively deposited. The outer, callose-containing amorphous layer consisted of remnants of FM1-43- and LTred-labelled organelles, of ER cisternae and of polysaccharide-containing secretory vesicles which became deposited in the absence of membrane retrieval (compound exocytosis). During formation of the inner, cellulosic layer exocytosis of secretory vesicles with the newly formed plasma membrane is coupled to endocytosis via coated vesicles. Migration of FM1-43- and LTred-stained organelles, of ER and of secretory vesicles towards the cell cortex and the deposition of a bipartite wound wall could also be induced by spot-like irradiation with ultraviolet light. Cytochalasin D reversibly inhibited the accumulation and deposition of organelles. Our study indicates that active, actin-dependent deposition of putative recycling endosomes is required for wound healing (plasma membrane repair) and supports the hypothesis that deposition of ER cisternae helps to restore wounding-disturbed Ca2+ metabolism. PMID:21668600

  2. A dark incubation period is important for Agrobacterium-mediated transformation of mature internode explants of sweet orange, grapefruit, citron, and a citrange rootstock.

    PubMed

    Marutani-Hert, Mizuri; Bowman, Kim D; McCollum, Greg T; Mirkov, T Erik; Evens, Terence J; Niedz, Randall P

    2012-01-01

    Citrus has an extended juvenile phase and trees can take 2-20 years to transition to the adult reproductive phase and produce fruit. For citrus variety development this substantially prolongs the time before adult traits, such as fruit yield and quality, can be evaluated. Methods to transform tissue from mature citrus trees would shorten the evaluation period via the direct production of adult phase transgenic citrus trees. Factors important for promoting shoot regeneration from internode explants from adult phase citrus trees were identified and included a dark incubation period and the use of the cytokinin zeatin riboside. Transgenic trees were produced from four citrus types including sweet orange, citron, grapefruit, and a trifoliate hybrid using the identified factors and factor settings. The critical importance of a dark incubation period for shoot regeneration was established. These results confirm previous reports on the feasibility of transforming mature tissue from sweet orange and are the first to document the transformation of mature tissue from grapefruit, citron, and a trifoliate hybrid.

  3. A Dark Incubation Period Is Important for Agrobacterium-Mediated Transformation of Mature Internode Explants of Sweet Orange, Grapefruit, Citron, and a Citrange Rootstock

    PubMed Central

    Marutani-Hert, Mizuri; Bowman, Kim D.; McCollum, Greg T.; Mirkov, T. Erik; Evens, Terence J.; Niedz, Randall P.

    2012-01-01

    Background Citrus has an extended juvenile phase and trees can take 2–20 years to transition to the adult reproductive phase and produce fruit. For citrus variety development this substantially prolongs the time before adult traits, such as fruit yield and quality, can be evaluated. Methods to transform tissue from mature citrus trees would shorten the evaluation period via the direct production of adult phase transgenic citrus trees. Methodology/Principal Findings Factors important for promoting shoot regeneration from internode explants from adult phase citrus trees were identified and included a dark incubation period and the use of the cytokinin zeatin riboside. Transgenic trees were produced from four citrus types including sweet orange, citron, grapefruit, and a trifoliate hybrid using the identified factors and factor settings. Significance The critical importance of a dark incubation period for shoot regeneration was established. These results confirm previous reports on the feasibility of transforming mature tissue from sweet orange and are the first to document the transformation of mature tissue from grapefruit, citron, and a trifoliate hybrid. PMID:23082165

  4. Studies on callose and cutin during the expression of competence and determination for organogenic nodule formation from internodes of Humulus lupulus var. Nugget.

    PubMed

    Fortes, Ana M; Testillano, Pilar S; Del Carmen Risueño, Maria; Pais, Maria S

    2002-09-01

    Callose and cutin deposition were followed by staining with Aniline Blue and Nile Red and by immunolocalization using antibodies raised against callose. Along with morphogenesis induction from internodes of Humulus lupulus var. Nugget, a temporal and spatial differential deposition of callose and cutin was observed. A cutin layer showing bright yellow autofluorescence appears, surrounding cells or groups of cells committed to express morphogenic competence. This cutin layer that evolves to a randomly organized network appeared underneath a callose layer and may create a specific cellular environment with altered permeability and altered receptors providing conditions for entering the cell cycle. The incipient callose accumulation in control explants cultured on basal medium suggests the involvement of callose in the initiation of the morphogenic programme leading to nodule formation. A scanning electron microscopic study during the organogenic process showed that before shoot bud regeneration, the cutin layer increases in thickness and acquires a smooth texture. This cutin layer is specific to nodular organogenic regions and disappeared with plantlet regeneration. This layer may control permeability to water and solute transfer throughout plantlet regeneration.

  5. Condensed tannin biosynthesis and polymerization synergistically condition carbon use, defense, sink strength and growth in Populus.

    PubMed

    Harding, Scott A; Xue, Liang-Jiao; Du, Lei; Nyamdari, Batbayar; Lindroth, Richard L; Sykes, Robert; Davis, Mark F; Tsai, Chung-Jui

    2014-11-01

    The partitioning of carbon for growth, storage and constitutive chemical defenses is widely framed in terms of a hypothetical sink-source differential that varies with nutrient supply. According to this framework, phenolics accrual is passive and occurs in source leaves when normal sink growth is not sustainable due to a nutrient limitation. In assessing this framework, we present gene and metabolite evidence that condensed tannin (CT) accrual is strongest in sink leaves and sequesters carbon in a way that impinges upon foliar sink strength and upon phenolic glycoside (PG) accrual in Populus. The work was based on two Populus fremontii × angustifolia backcross lines with contrasting rates of CT accrual and growth, and equally large foliar PG reserves. However, foliar PG accrual was developmentally delayed in the high-CT, slow-growth line (SG), and nitrogen-limitation led to increased foliar PG accrual only in the low-CT, fast-growth line (FG). Metabolite profiling of developing leaves indicated comparatively carbon-limited amino acid metabolism, depletion of several Krebs cycle intermediates and reduced organ sink strength in SG. Gene profiling indicated that CT synthesis decreased as leaves expanded and PGs increased. A most striking finding was that the nitrogenous monoamine phenylethylamine accumulated only in leaves of SG plants. The potential negative impact of CT hyper-accumulation on foliar sink strength, as well as a mechanism for phenylethylamine involvement in CT polymerization in Populus are discussed. Starch accrual in source leaves and CT accrual in sink leaves of SG may both contribute to the maintenance of a slow-growth phenotype suited to survival in nutrient-poor habitats. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

    PubMed

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

    2007-07-01

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

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

    PubMed

    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.

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

    PubMed

    Thompson, Stacey Lee; Lamothe, Manuel; Meirmans, Patrick G; Périnet, Pierre; Isabel, Nathalie

    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 nigra and its hybrids have been extensively planted since the 1800s. Single nucleotide polymorphisms (SNPs) that appeared fixed within each species were characterized by DNA-sequencing pools of pure individuals. Thirty-five of these diagnostic SNPs were employed in a high-throughput assay that genotyped 635 trees of different age classes, sampled from 15 sites with various degrees of anthropogenic disturbance. The degree of admixture within sampled trees was then assessed through Bayesian clustering of genotypes. Hybrids were present in seven of the populations, with 2.4% of all sampled trees showing spontaneous admixture. Sites with hybrids were significantly more disturbed than pure stands, while hybrids comprised both immature juveniles and trees of reproductive age. All three possible F1s were detected. Advanced-generation hybrids were consistently biased towards P. balsamifera regardless of whether hybridization had occurred with P. deltoides or P. nigra. Gene exchange between P. deltoides and P. nigra was not detected beyond the F1 generation; however, detection of a trihybrid demonstrates that even this apparent reproductive isolation does not necessarily result in an evolutionary dead end. Collectively, results demonstrate the natural fertility of hybrid poplars and suggest that introduced genes could potentially affect the genetic integrity of native trees, similar to that arising from introgression between natives.

  9. Comparative genome analysis of Pseudomonas genomes including Populus-associated isolates

    DOE PAGES

    Jun, Se Ran; Wassenaar, Trudy; Nookaew, Intawat; ...

    2016-01-01

    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 influencing phylogenetic diversity and heterogeneity. In this study, comparative genome analysis was performed on over one thousand Pseudomonas genomes, including 21 Pseudomonas strains isolated from the roots of native Populus deltoides. Based on average amino acid identity, genomic clusters were identified within the Pseudomonas genus, which showed agreements with clades by NCBI and cliques by IMG. The P. fluorescens group was organized into 20 distinct genomic clusters, representing enormous diversity and heterogeneity. The speciesmore » P. aeruginosa showed clear distinction in their genomic relatedness compared to other Pseudomonas species groups based on the pan and core genome analysis. The 19 isolates of our 21 Populus-associated isolates formed three distinct subgroups within the P. fluorescens major group, supported by pathway profiles analysis, while two isolates were more closely related to P. chlororaphis and P. putida. The specific genes to Populus-associated subgroups were identified where genes specific to subgroup 1 include several sensory systems such as proteins which act in two-component signal transduction, a TonB-dependent receptor, and a phosphorelay sensor; specific genes to subgroup 2 contain unique hypothetical genes; and genes specific to subgroup 3 organisms have a different hydrolase activity. IMPORTANCE The comparative genome analyses of the genus Pseudomonas that included Populus-associated isolates resulted in novel insights into high diversity of Pseudomonas. Consistent and robust genomic clusters with phylogenetic homogeneity were identified, which resolved species-clades that are not clearly defined by 16S rRNA gene sequence analysis alone. The genomic clusters may be reflective of distinct ecological niches to which the organisms have adapted, but

  10. Comparative genome analysis of Pseudomonas genomes including Populus-associated isolates

    SciTech Connect

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

    2016-01-01

    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 influencing phylogenetic diversity and heterogeneity. In this study, comparative genome analysis was performed on over one thousand Pseudomonas genomes, including 21 Pseudomonas strains isolated from the roots of native Populus deltoides. Based on average amino acid identity, genomic clusters were identified within the Pseudomonas genus, which showed agreements with clades by NCBI and cliques by IMG. The P. fluorescens group was organized into 20 distinct genomic clusters, representing enormous diversity and heterogeneity. The species P. aeruginosa showed clear distinction in their genomic relatedness compared to other Pseudomonas species groups based on the pan and core genome analysis. The 19 isolates of our 21 Populus-associated isolates formed three distinct subgroups within the P. fluorescens major group, supported by pathway profiles analysis, while two isolates were more closely related to P. chlororaphis and P. putida. The specific genes to Populus-associated subgroups were identified where genes specific to subgroup 1 include several sensory systems such as proteins which act in two-component signal transduction, a TonB-dependent receptor, and a phosphorelay sensor; specific genes to subgroup 2 contain unique hypothetical genes; and genes specific to subgroup 3 organisms have a different hydrolase activity. IMPORTANCE The comparative genome analyses of the genus Pseudomonas that included Populus-associated isolates resulted in novel insights into high diversity of Pseudomonas. Consistent and robust genomic clusters with phylogenetic homogeneity were identified, which resolved species-clades that are not clearly defined by 16S rRNA gene sequence analysis alone. The genomic clusters may be reflective of distinct ecological niches to which the organisms have adapted, but this

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

    PubMed

    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.

  12. Consolidated bioprocessing of Populus using Clostridium (Ruminiclostridium) thermocellum: a case study on the impact of lignin composition and structure

    SciTech Connect

    Dumitrache, Alexandru; Akinosho, Hannah; Rodriguez, Miguel; Meng, Xianzhi; Yoo, Chang Geun; Natzke, Jace; Engle, Nancy L.; Sykes, Robert W.; Tschaplinski, Timothy J.; Muchero, Wellington; Ragauskas, Arthur J.; Davison, Brian H.; Brown, Steven D.

    2016-02-04

    Background: Higher ratios of syringyl-to-guaiacyl (S/G) lignin components of Populus were shown to improve sugar release by enzymatic hydrolysis using commercial blends. Cellulolytic microbes are often robust biomass hydrolyzers and may offer cost advantages; however, it is unknown whether their activity can also be significantly influenced by the ratio of different monolignol types in Populus biomass. Hydrolysis and fermentation of autoclaved, but otherwise not pretreated Populus trichocarpa by Clostridium thermocellum ATCC 27405 was compared using feedstocks that had similar carbohydrate and total lignin contents but differed in S/G ratios. Results: Populus with an S/G ratio of 2.1 was converted more rapidly and to a greater extent compared to similar biomass that had a ratio of 1.2. For either microbes or commercial enzymes, an approximate 50% relative difference in total solids solubilization was measured for both biomasses, which suggests that the differences and limitations in the microbial breakdown of lignocellulose may be largely from the enzymatic hydrolytic process. Unexpectedly, the reduction in glucan content per gram solid in the residual microbially processed biomass was similar (17–18%) irrespective of S/G ratio, pointing to a similar mechanism of solubilization that proceeded at different rates. Fermentation metabolome testing did not reveal the release of known biomass-derived alcohol and aldehyde inhibitors that could explain observed differences in microbial hydrolytic activity. Biomass-derived p-hydroxybenzoic acid was up to ninefold higher in low S/G ratio biomass fermentations, but was not found to be inhibitory in subsequent test fermentations. Cellulose crystallinity and degree of polymerization did not vary between Populus lines and had minor changes after fermentation. However, lignin molecular weights and cellulose accessibility determined by Simons’ staining were positively correlated to the S/G content. Conclusions: Higher S

  13. Consolidated bioprocessing of Populus using Clostridium (Ruminiclostridium) thermocellum: a case study on the impact of lignin composition and structure

    DOE PAGES

    Dumitrache, Alexandru; Akinosho, Hannah; Rodriguez, Miguel; ...

    2016-02-04

    Background: Higher ratios of syringyl-to-guaiacyl (S/G) lignin components of Populus were shown to improve sugar release by enzymatic hydrolysis using commercial blends. Cellulolytic microbes are often robust biomass hydrolyzers and may offer cost advantages; however, it is unknown whether their activity can also be significantly influenced by the ratio of different monolignol types in Populus biomass. Hydrolysis and fermentation of autoclaved, but otherwise not pretreated Populus trichocarpa by Clostridium thermocellum ATCC 27405 was compared using feedstocks that had similar carbohydrate and total lignin contents but differed in S/G ratios. Results: Populus with an S/G ratio of 2.1 was converted moremore » rapidly and to a greater extent compared to similar biomass that had a ratio of 1.2. For either microbes or commercial enzymes, an approximate 50% relative difference in total solids solubilization was measured for both biomasses, which suggests that the differences and limitations in the microbial breakdown of lignocellulose may be largely from the enzymatic hydrolytic process. Unexpectedly, the reduction in glucan content per gram solid in the residual microbially processed biomass was similar (17–18%) irrespective of S/G ratio, pointing to a similar mechanism of solubilization that proceeded at different rates. Fermentation metabolome testing did not reveal the release of known biomass-derived alcohol and aldehyde inhibitors that could explain observed differences in microbial hydrolytic activity. Biomass-derived p-hydroxybenzoic acid was up to ninefold higher in low S/G ratio biomass fermentations, but was not found to be inhibitory in subsequent test fermentations. Cellulose crystallinity and degree of polymerization did not vary between Populus lines and had minor changes after fermentation. However, lignin molecular weights and cellulose accessibility determined by Simons’ staining were positively correlated to the S/G content. Conclusions: Higher

  14. Expression of cell wall related genes in basal and ear internodes of silking brown-midrib-3, caffeic acid O-methyltransferase (COMT) down-regulated, and normal maize plants

    PubMed Central

    Guillaumie, Sabine; Goffner, Deborah; Barbier, Odile; Martinant, Jean-Pierre; Pichon, Magalie; Barrière, Yves

    2008-01-01

    Background Silage maize is a major forage and energy resource for cattle feeding, and several studies have shown that lignin content and structure are the determining factors in forage maize feeding value. In maize, four natural brown-midrib mutants have modified lignin content, lignin structure and cell wall digestibility. The greatest lignin reduction and the highest cell wall digestibility were observed in the brown-midrib-3 (bm3) mutant, which is disrupted in the caffeic acid O-methyltransferase (COMT) gene. Results Expression of cell wall related genes was investigated in basal and ear internodes of normal, COMT antisens (AS225), and bm3 maize plants of the INRA F2 line. A cell wall macro-array was developed with 651 gene specific tags of genes specifically involved in cell wall biogenesis. When comparing basal (older lignifying) and ear (younger lignifying) internodes of the normal line, all genes known to be involved in constitutive monolignol biosynthesis had a higher expression in younger ear internodes. The expression of the COMT gene was heavily reduced, especially in the younger lignifying tissues of the ear internode. Despite the fact that AS225 transgene expression was driven only in sclerenchyma tissues, COMT expression was also heavily reduced in AS225 ear and basal internodes. COMT disruption or down-regulation led to differential expressions of a few lignin pathway genes, which were all over-expressed, except for a phenylalanine ammonia-lyase gene. More unexpectedly, several transcription factor genes, cell signaling genes, transport and detoxification genes, genes involved in cell wall carbohydrate metabolism and genes encoding cell wall proteins, were differentially expressed, and mostly over-expressed, in COMT-deficient plants. Conclusion Differential gene expressions in COMT-deficient plants highlighted a probable disturbance in cell wall assembly. In addition, the gene expressions suggested modified chronology of the different events leading

  15. Populus trichocarpa encodes small, effector-like secreted proteins that are highly induced during mutualistic symbiosis

    DOE PAGES

    Plett, Jonathan M.; Yin, Hengfu; Mewalal, Ritesh; ...

    2017-03-23

    During symbiosis, organisms use a range of metabolic and protein-based signals to communicate. Of these protein signals, one class is defined as ‘effectors’, i.e., small secreted proteins (SSPs) that cause phenotypical and physiological changes in another organism. To date, protein-based effectors have been described in aphids, nematodes, fungi and bacteria. Using RNA sequencing of Populus trichocarpa roots in mutualistic symbiosis with the ectomycorrhizal fungus Laccaria bicolor, we sought to determine if host plants also contain genes encoding effector-like proteins. We identified 417 plant-encoded putative SSPs that were significantly regulated during this interaction, including 161 SSPs specific to P. trichocarpa andmore » 15 SSPs exhibiting expansion in Populus and closely related lineages. We demonstrate that a subset of these SSPs can enter L. bicolor hyphae, localize to the nucleus and affect hyphal growth and morphology. Finally, we conclude that plants encode proteins that appear to function as effector proteins that may regulate symbiotic associations.« less

  16. Extensive allelic variation in gene expression in populus F1 hybrids.

    PubMed

    Zhuang, Yan; Adams, Keith L

    2007-12-01

    Hybridization between plant species can induce speciation as well as phenotypic novelty and heterosis. Hybrids also can show genome rearrangements and gene expression changes compared with their parents. Here we determined the allelic variation in gene expression in Populus trichocarpa x Populus deltoides F(1) hybrids. Among 30 genes analyzed in four independently formed hybrids, 17 showed >1.5-fold expression biases for one of the two alleles, and there was monoallelic expression of one gene. Expression ratios of the alleles differed between leaves and stems for 10 genes. The results suggest differential regulation of the two parental alleles in the hybrids. To determine if the allelic expression biases were caused by hybridization we compared the ratios of species-specific transcripts between an F(1) hybrid and its parents. Thirteen of 19 genes showed allelic expression ratios in the hybrid that were significantly different from the ratios of the parental species. The P. deltoides allele of one gene was silenced in the hybrid. Modes of gene regulation were inferred from the hybrid-parent comparisons. Cis-regulation was inferred for 6 genes, trans-regulation for 1 gene, and combined cis- and trans-regulation for 9 genes. The results from this study indicate that hybridization between plant species can have extensive effects on allelic expression patterns, some of which might lead to phenotypic changes.

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

    PubMed

    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.

  18. Fermentation of dilute acid pretreated Populus by Clostridium thermocellum, Caldicellulosiruptor bescii, and Caldicellulosiruptor obsidiansis

    DOE PAGES

    Yee, Kelsey L.; Rodriguez, Jr., Miguel; Hamilton, Choo Yieng; ...

    2015-07-25

    Consolidated bioprocessing (CBP), which merges enzyme production, biomass hydrolysis, and fermentation into a single step, has the potential to become an efficient and economic strategy for the bioconversion of lignocellulosic feedstocks to transportation fuels or chemicals. In this study, we evaluated Clostridium thermocellum, Caldicellulosiruptor bescii, and Caldicellulosiruptor obsidiansis, three , thermophilic,cellulolytic, mixed-acid fermenting candidate CBP microorganisms, for their fermentation capabilities using dilute acid pretreated Populus as a model biomass feedstock. Under pH controlled, anaerobic fermentation conditions, each candidate successfully digested a minimum of 75% of the cellulose from dilute acid pretreated Populus, as indicated by an increase in planktonic cellsmore » and end-product metabolites and a concurrent decrease in glucan content. C. thermocellum, which employs a cellulosomal approach to biomass degradation, required 120 hours to achieve 75% cellulose utilization. In contrast, the non-cellulosomal, secreted hydrolytic enzyme system of the Caldicellulosiruptor sp. required 300 hours to achieve similar results. End-point fermentation conversions for C. thermocellum, C. bescii, and C. obsidiansis were determined to be 0.29, 0.34, and 0.38 grams of total metabolites per gram of loaded glucan, respectively. This data provide a starting point for future strain engineering efforts that can serve to improve the biomass fermentation capabilities of these three promising candidate CBP platforms.« less

  19. Phytoremediation of trichlorophenol by Phase II metabolism in transgenic Arabidopsis overexpressing a Populus glucosyltransferase.

    PubMed

    Su, Zhen-Hong; Xu, Zhi-Sheng; Peng, Ri-He; Tian, Yong-Sheng; Zhao, Wei; Han, Hong-Juan; Yao, Quan-Hong; Wu, Ai-Zhong

    2012-04-03

    Trichlorophenol (TCP) and its derivatives are introduced into the environment through numerous sources, including wood preservatives and biocides. Environmental contamination by TCPs is associated with human health risks, necessitating the development of cost-effective remediation techniques. Efficient phytoremediation of TCP is potentially feasible because it contains a hydroxyl group and is suitable for direct phase II metabolism. In this study, we present a system for TCP phytoremediation based on sugar conjugation by overexpressing a Populus putative UDP-glc-dependent glycosyltransferase (UGT). The enzyme PtUGT72B1 displayed the highest TCP-conjugating activity among all reported UGTs. Transgenic Arabidopsis demonstrated significantly enhanced tolerances to 2,4,5-TCP and 2,4,6-TCP. Transgenic plants also exhibited a strikingly higher capacity to remove TCP from their media. This work indicates that Populus UGT overexpression in Arabidopsis may be an efficient method for phytoremoval and degradation of TCP. Our findings have the potential to provide a suitable remediation strategy for sites contaminated by TCP.

  20. Artificial defoliation effect on Populus growth, biomass production, and total nonstructural carbohydrate concentration

    SciTech Connect

    Reichenbacker, R.R.; Hart, E.R.; Schultz, R.C.

    1996-06-01

    The impact of artificial defoliation on Populus growth, biomass production, and total nonstructural carbohydrate concentration was examined. Four Populus clones were field planted and artificially defoliated. Assigned defoliation levels (0, 25, 50, or 75%) were applied to leaves of leaf plastochron index 0 through 8 during a 6-d period in a 3-step incremental manner to simulate cottonwood leaf beetle, Chrysomela scripta F., larval feeding patterns. Artificial defoliations were timed to coincide with the outbreaks of natural beetle populations in adjacent areas. After 2 growing seasons, trees were measured for height, diameter, and biomass accumulation. Root samples were collected from 0 and 75% defoliation treatments for each clone. Biomass was reduced an average of 33% as defoliation level increased from 0 to 75%. As defoliation level increased from 0 to 75%, a consistent allocation ratio of biomass to 2/3 above and 1/3 below ground components continued in all clones. An overcompensation response occurred in above ground biomass when a defoliation level of 25% was applied. Between 25 and 75% a strong linear trend of decreasing biomass as defoliation increased was indicated. Vitality of the tree, as indicated by total nonstructural carbohydrate content, was affected only slightly by increasing defoliation. 26 refs., 1 fig., 6 tabs.

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

    DOE PAGES

    Bryan, Anthony C.; Jawdy, Sara; Gunter, Lee; ...

    2016-04-15

    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.008G06400, 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 onmore » a mild pretreatment prior to chemical extraction of sugars. Metabolite profiling suggests the transgene modulates phenolics that are associated with the cell wall structure. Finally, we propose a model in which this particular laccase has a range of functions related to oxidation of phenolics that interact with lignin in the cell wall.« less

  2. Enrichment of Root Endophytic Bacteria from Populus deltoides and Single-Cell-Genomics Analysis

    DOE PAGES

    Utturkar, Sagar M.; Cude, W. Nathan; Robeson, Jr., Michael S.; ...

    2016-07-15

    Bacterial endophytes that colonize Populus trees contribute to nutrient acquisition, prime immunity responses, and directly or indirectly increase both above- and below-ground biomasses. Endophytes are embedded within plant material, so physical separation and isolation are difficult tasks. Application of culture-independent methods, such as metagenome or bacterial transcriptome sequencing, has been limited due to the predominance of DNA from the plant biomass. In this paper, we present a modified differential and density gradient centrifugation-based protocol for the separation of endophytic bacteria from Populus roots. This protocol achieved substantial reduction in contaminating plant DNA, allowed enrichment of endophytic bacteria away from themore » plant material, and enabled single-cell genomics analysis. Four single-cell genomes were selected for whole-genome amplification based on their rarity in the microbiome (potentially uncultured taxa) as well as their inferred abilities to form associations with plants. Bioinformatics analyses, including assembly, contamination removal, and completeness estimation, were performed to obtain single-amplified genomes (SAGs) of organisms from the phyla Armatimonadetes, Verrucomicrobia, and Planctomycetes, which were unrepresented in our previous cultivation efforts. Finally, comparative genomic analysis revealed unique characteristics of each SAG that could facilitate future cultivation efforts for these bacteria.« less

  3. The transcriptome of Populus in elevated CO2 reveals increased anthocyanin biosynthesis during delayed autumnal senescence

    SciTech Connect

    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.

  4. Formation of wood secondary cell wall may involve two type cellulose synthase complexes in Populus.

    PubMed

    Xi, Wang; Song, Dongliang; Sun, Jiayan; Shen, Junhui; Li, Laigeng

    2017-03-01

    Cellulose biosynthesis is mediated by cellulose synthases (CesAs), which constitute into rosette-like cellulose synthase complexe (CSC) on the plasma membrane. Two types of CSCs in Arabidopsis are believed to be involved in cellulose synthesis in the primary cell wall and secondary cell walls, respectively. In this work, we found that the two type CSCs participated cellulose biosynthesis in differentiating xylem cells undergoing secondary cell wall thickening in Populus. During the cell wall thickening process, expression of one type CSC genes increased while expression of the other type CSC genes decreased. Suppression of different type CSC genes both affected the wall-thickening and disrupted the multilaminar structure of the secondary cell walls. When CesA7A was suppressed, crystalline cellulose content was reduced, which, however, showed an increase when CesA3D was suppressed. The CesA suppression also affected cellulose digestibility of the wood cell walls. The results suggest that two type CSCs are involved in coordinating the cellulose biosynthesis in formation of the multilaminar structure in Populus wood secondary cell walls.

  5. Effect of rotation, site, and clone on the chemical composition of Populus hybrids

    SciTech Connect

    Blanckenhorn, P.R.; Bowersox, T.W.; Kuklewski, K.M.; Stimely, S.L.

    1985-01-01

    Chemical content values were determined for three Populus clones grown on two dissimilar sites by component (wood, bark, and wood/bark specimens), tissue age (1-, 2- and 4-year-old), and rotation. The chemical content values obtained included extractives, holocellulose, ..alpha..-cellulose, and lignin. In general, analysis of the data for the wood, bark, and wood/bark specimens indicated that: 1) wood was high in holocellulose and ..alpha..-cellulose content compared to bark, 2) bark was high in lignin and extractive content values compared to wood, and 3) wood/bark chemical content values were between the values for the wood and bark specimens. The chemical content data were analyzed to identify: 1) significant differences between rotations by component (wood, bark and wood/bark) for a given age, clone, and site, and 2) significant differences between sites for four-year-old wood, bark and wood/bark specimens of a given rotation, and clone. Statistical analyses indicated that significant differences existed among clones, sites, ages, and rotations. Within the wood, bark and wood/bark specimens, tissue age, rotation, and site influenced the chemical content values more than the parentage. Potential chemical yields derived from the three Populus hybrid clones investigated will depend on component, age, rotation, and site with limited parentage effects.

  6. Transport and use of CO sub 2 in the xylem sap of Populus deltoides

    SciTech Connect

    Stringer, J.W.; Kimmerer, T.W. )

    1990-05-01

    Results of recent experiments indicate an internal cycling of respiratory CO{sub 2} in woody plants. The CO{sub 2} concentration of xylem sap expressed from the twigs of field grown Populus deltoides ranged from .14 to .50 mM. The pH of the xylem sap was 5.7 to 6.7, providing a significant bicarbonate concentration in many samples. Total dissolved inorganic carbon (DIC = CO{sub 2} + H{sub 2}CO{sub 3} + HCO{sub 3}{sup {minus}}) was 0.5 mM to 1.3 mM. Results from the analysis of xylem sap of 10 other species of woody plants were similar. To determine the fate of DIC delivered to the leaves of Populus deltoides, excised leaves were fed 1mM NaHCO{sub 3} (2 {mu}Ci NaH{sup 14}CO{sub 3} ml{sup {minus}1}). Less than 0.4% of the label escaped from the leaves, and {ge}93% was fixed. Of the carbon fixed 56% of the {sup 14}C was found in the petiole and midrib, and 14% was in the major veins, with the remaining 30% in the minor veins and lamina. Shading of the peptiole and midrib of leaves decreased the amount of fixed carbon in these tissues to 38% and increased the amount in the lamina to 55%.

  7. Leaf and whole tree adaptations to mild salinity in field grown Populus euphratica.

    PubMed

    Zeng, Fanjiang; Yan, Hailong; Arndt, Stefan K

    2009-10-01

    Populus euphratica Oliv. is a highly salt tolerant tree species, and this study represents the first comprehensive investigation of salt tolerance mechanisms of mature trees of P. euphratica in the field. We measured NaCl concentration in xylem sap, NaCl accumulation in leaves, the effect of NaCl on leaf physiological parameters and osmotic adjustment and the allocation and distribution of NaCl between different plant organs on a whole plant level in trees exposed to mild saline groundwater (around 30 mM) in China. Populus euphratica showed three key mechanisms of salt tolerance. The primary mechanism had a strong control over Na(+) and Cl(-) uptake with effective exclusion mechanisms for Cl(-) with up to 99% of the external NaCl being excluded from the xylem. Secondly, the trees allocated large proportions of NaCl into the leaves, which served as a salt elimination mechanism as the leaves are ultimately shed at the end of the growing season. Thirdly, the trees tolerated high foliar Na(+) concentrations through a combination of osmotic adjustment using sucrose and probable sequestering of Na(+) in the apoplast. Our results indicate that the control of Na(+) and Cl(-) uptake and the regulation of Na(+) and Cl(-) delivery to the shoot are key to salt tolerance of P. euphratica in the field with tolerance of high Na(+) concentrations in leaves being a critical component.

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

    PubMed

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

    2009-09-15

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

  9. Enzymatic digestibility and pretreatment degradation products of AFEX-treated hardwoods (Populus nigra).

    PubMed

    Balan, Venkatesh; Sousa, Leonardo da Costa; Chundawat, Shishir P S; Marshall, Derek; Sharma, Lekh N; Chambliss, C Kevin; Dale, Bruce E

    2009-01-01

    There is a growing need to find alternatives to crude oil as the primary feed stock for the chemicals and fuel industry and ethanol has been demonstrated to be a viable alternative. Among the various feed stocks for producing ethanol, poplar (Populus nigra x Populus maximowiczii) is considered to have great potential as a biorefinery feedstock in the United States, due to their widespread availability and good productivity in several parts of the country. We have optimized AFEX pretreatment conditions (180 degrees C, 2:1 ammonia to biomass loading, 233% moisture, 30 minutes residence time) and by using various combinations of enzymes (commercical celluloses and xylanases) to achieve high glucan and xylan conversion (93 and 65%, respectively). We have also identified and quantified several important degradation products formed during AFEX using liquid chromatography followed by mass spectrometry (LC-MS/MS). As a part of degradation product analysis, we have also quantified oligosaccharides in the AFEX water wash extracts by acid hydrolysis. It is interesting to note that corn stover (C4 grass) can be pretreated effectively using mild AFEX pretreatment conditions, while on the other hand hardwood poplar requires much harsher AFEX conditions to obtain equivalent sugar yields upon enzymatic hydrolysis. Comparing corn stover and poplar, we conclude that pretreatment severity and enzymatic hydrolysis efficiency are dictated to a large extent by lignin carbohydrate complexes and arabinoxylan cross-linkages for AFEX.

  10. Rapid phytochemical analysis of birch (Betula) and poplar (Populus) foliage by near-infrared reflectance spectroscopy.

    PubMed

    Rubert-Nason, Kennedy F; Holeski, Liza M; Couture, John J; Gusse, Adam; Undersander, Daniel J; Lindroth, Richard L

    2013-02-01

    Poplar (Populus) and birch (Betula) species are widely distributed throughout the northern hemisphere, where they are foundation species in forest ecosystems and serve as important sources of pulpwood. The ecology of these species is strongly linked to their foliar chemistry, creating demand for a rapid, inexpensive method to analyze phytochemistry. Our study demonstrates the feasibility of using near-infrared reflectance spectroscopy (NIRS) as an inexpensive, high-throughput tool for determining primary (e.g., nitrogen, sugars, starch) and secondary (e.g., tannins, phenolic glycosides) foliar chemistry of Populus and Betula species, and identifies conditions necessary for obtaining reliable quantitative data. We developed calibrations with high predictive power (residual predictive deviations ≤ 7.4) by relating phytochemical concentrations determined with classical analytical methods (e.g., spectrophotometric assays, liquid chromatography) to NIR spectra, using modified partial least squares regression. We determine that NIRS, although less sensitive and precise than classical methods for some compounds, provides useful predictions in a much faster, less expensive manner than do classical methods.

  11. Different autosomes evolved into sex chromosomes in the sister genera of Salix and Populus.

    PubMed

    Hou, Jing; Ye, Ning; Zhang, Defang; Chen, Yingnan; Fang, Lecheng; Dai, Xiaogang; Yin, Tongming

    2015-03-13

    Willows (Salix) and poplars (Populus) are dioecious plants in Salicaceae family. Sex chromosome in poplar genome was consistently reported to be associated with chromosome XIX. In contrast to poplar, this study revealed that chromosome XV was sex chromosome in willow. Previous studies revealed that both ZZ/ZW and XX/XY sex-determining systems could be present in some species of Populus. In this study, sex of S. suchowensis was found to be determined by the ZW system in which the female was the heterogametic gender. Gene syntenic and collinear comparisons revealed macrosynteny between sex chromosomes and the corresponding autosomes between these two lineages. By contrast, no syntenic segments were found to be shared between poplar's and willow's sex chromosomes. Syntenic analysis also revealed substantial chromosome rearrangements between willow's alternate sex chromatids. Since willow and poplar originate from a common ancestor, we proposed that evolution of autosomes into sex chromosomes in these two lineages occurred after their divergence. Results of this study indicate that sex chromosomes in Salicaceae are still at the early stage of evolutionary divergence. Additionally, this study provided valuable information for better understanding the genetics and evolution of sex chromosome in dioecious plants.

  12. Extensive Allelic Variation in Gene Expression in Populus F1 Hybrids

    PubMed Central

    Zhuang, Yan; Adams, Keith L.

    2007-01-01

    Hybridization between plant species can induce speciation as well as phenotypic novelty and heterosis. Hybrids also can show genome rearrangements and gene expression changes compared with their parents. Here we determined the allelic variation in gene expression in Populus trichocarpa × Populus deltoides F1 hybrids. Among 30 genes analyzed in four independently formed hybrids, 17 showed >1.5-fold expression biases for one of the two alleles, and there was monoallelic expression of one gene. Expression ratios of the alleles differed between leaves and stems for 10 genes. The results suggest differential regulation of the two parental alleles in the hybrids. To determine if the allelic expression biases were caused by hybridization we compared the ratios of species-specific transcripts between an F1 hybrid and its parents. Thirteen of 19 genes showed allelic expression ratios in the hybrid that were significantly different from the ratios of the parental species. The P. deltoides allele of one gene was silenced in the hybrid. Modes of gene regulation were inferred from the hybrid–parent comparisons. Cis-regulation was inferred for 6 genes, trans-regulation for 1 gene, and combined cis- and trans-regulation for 9 genes. The results from this study indicate that hybridization between plant species can have extensive effects on allelic expression patterns, some of which might lead to phenotypic changes. PMID:18073418

  13. Arbuscular mycorrhizal fungi associated with Populus-Salix stands in a semiarid riparian ecosystem

    USGS Publications Warehouse

    Beauchamp, Vanessa B.; Stromberg, J.C.; Stutz, J.C.

    2006-01-01

    ??? This study examined the activity, species richness, and species composition of the arbuscular mycorrhizal fungal (AMF) community of Populus-Salix stands on the Verde River (Arizona, USA), quantified patterns of AMF richness and colonization along complex floodplain gradients, and identified environmental variables responsible for structuring the AMF community. ??? Samples from 61 Populus-Salix stands were analyzed for AMF and herbaceous composition, AMF colonization, gravimetric soil moisture, soil texture, per cent organic matter, pH, and concentrations of nitrate, bicarbonate phosphorus and exchangeable potassium. ??? AMF species richness declined with stand age and distance from and elevation above the channel and was positively related to perennial species cover and richness and gravimetric soil moisture. Distance from and elevation above the active channel, forest age, annual species cover, perennial species richness, and exchangeable potassium concentration all played a role in structuring the AMF community in this riparian area. ??? Most AMF species were found across a wide range of soil conditions, but a subset of species tended to occur more often in hydric areas. This group of riparian affiliate AMF species includes several not previously encountered in the surrounding Sonoran desert. ?? New Phytologist (2006).

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

    PubMed

    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.

  15. Differential Detection of Genetic Loci Underlying Stem and Root Lignin Content in Populus

    SciTech Connect

    Yin, Tongming; Zhang, Xinye; Gunter, Lee E; Ranjan, Priya; Sykes, Robert; Davis, Dr. Mark F.; Wullschleger, Stan D; Tuskan, Gerald A

    2010-01-01

    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.

  16. Differential detection of genetic loci underlying stem and root lignin content in Populus

    SciTech Connect

    Tuskan, Gerald A; Yin, Tongming; Zhang, Xinye; Gunter, Lee E; Ranjan, Priya; Sykes, Robert; Davis, Dr. Mark F.; Wullschleger, Stan D

    2010-11-01

    For simultaneous applications directed towards improved pulp yields, enhanced bioethanol production and increased carbon sequestration, it would be desirable to reduce lignin in the harvested stem while increasing the lignin content in nonharvested roots. 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.

  17. Methylation of miRNA genes in the response to temperature stress in Populus simonii

    PubMed Central

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

    2015-01-01

    DNA methylation and miRNAs provide crucial regulation of the transcriptional and post-transcriptional responses to abiotic stress. In this study, we used methylation-sensitive amplification polymorphisms to identify 1066 sites that were differentially methylated in response to temperature stress in Populus simonii. Among these loci, BLAST searches of miRBase identified seven miRNA genes. Expression analysis by quantitative real-time PCR suggested that the methylation pattern of these miRNA genes probably influences their expression. Annotation of these miRNA genes in the sequenced genome of Populus trichocarpa found three target genes (Potri.007G090400, Potri.014G042200, and Potri.010G176000) for the miRNAs produced from five genes (Ptc-MIR396e and g, Ptc-MIR156i and j, and Ptc-MIR390c) respectively. The products of these target genes function in lipid metabolism to deplete lipid peroxide. We also constructed a network based on the interactions between DNA methylation and miRNAs, miRNAs and target genes, and the products of target genes and the metabolic factors that they affect, including H2O2, malondialdehyde, catalase (CAT), and superoxide dismutase. Our results suggested that DNA methylation probably regulates the expression of miRNA genes, thus affecting expression of their target genes, likely through the gene-silencing function of miRNAs, to maintain cell survival under abiotic stress conditions. PMID:26579167

  18. Fractionation of alkali-solubilized hemicelluloses from delignified Populus gansuensis: structure and properties.

    PubMed

    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.

  19. How to Regenerate and Protect Desert Riparian Populus euphratica Forest in Arid Areas

    PubMed Central

    Ling, Hongbo; Zhang, Pei; Xu, Hailiang; Zhao, Xinfeng

    2015-01-01

    We found that the most suitable flooding disturbance model for regenerating Populus euphratica forest was two to three times per year with a duration of 15–20 days and an intensity of 25–30 m3/s. The flooding should take place during the seed emergence to young tree growth stages, and should be based on flooding experiments and data from vegetation quadrats and ecological water conveyance. Furthermore, we found that tree-ring width index for P. euphratica declined as the groundwater depth increased, and ascertained that the minimum groundwater depths for young trees, near-mature trees, mature trees and over-mature trees were 4.0 m, 5.0–5.4 m, 6.9 m and 7.8 m, respectively. These were derived from a quantitative relationship model between groundwater depth and tree-ring width index. The range for ecological water conveyance volume was 311–320 million m3 in the lower reaches of the Tarim River. This study not only provides a technical basis for sustainable ecological water conveyance in the Tarim River Basin, but also offers a theoretical guide and scientific information that could be used in similar areas to regenerate and protect Populus euphratica around the world. PMID:26481290

  20. Enrichment of Root Endophytic Bacteria from Populus deltoides and Single-Cell-Genomics Analysis

    SciTech Connect

    Utturkar, Sagar M.; Cude, W. Nathan; Robeson, Jr., Michael S.; Yang, Zamin Koo; Klingeman, Dawn Marie; Land, Miriam L.; Allman, Steve L.; Lu, Tse-Yuan S.; Brown, Steven D.; Schadt, Christopher Warren; Podar, Mircea; Doktycz, Mitchel J.; Pelletier, Dale A.

    2016-07-15

    Bacterial endophytes that colonize Populus trees contribute to nutrient acquisition, prime immunity responses, and directly or indirectly increase both above- and below-ground biomasses. Endophytes are embedded within plant material, so physical separation and isolation are difficult tasks. Application of culture-independent methods, such as metagenome or bacterial transcriptome sequencing, has been limited due to the predominance of DNA from the plant biomass. In this paper, we present a modified differential and density gradient centrifugation-based protocol for the separation of endophytic bacteria from Populus roots. This protocol achieved substantial reduction in contaminating plant DNA, allowed enrichment of endophytic bacteria away from the plant material, and enabled single-cell genomics analysis. Four single-cell genomes were selected for whole-genome amplification based on their rarity in the microbiome (potentially uncultured taxa) as well as their inferred abilities to form associations with plants. Bioinformatics analyses, including assembly, contamination removal, and completeness estimation, were performed to obtain single-amplified genomes (SAGs) of organisms from the phyla Armatimonadetes, Verrucomicrobia, and Planctomycetes, which were unrepresented in our previous cultivation efforts. Finally, comparative genomic analysis revealed unique characteristics of each SAG that could facilitate future cultivation efforts for these bacteria.

  1. Constitutively Elevated Salicylic Acid Levels Alter Photosynthesis and Oxidative State but Not Growth in Transgenic Populus[C][W

    PubMed Central

    Xue, Liang-Jiao; Guo, Wenbing; Yuan, Yinan; Anino, Edward O.; Nyamdari, Batbayar; Wilson, Mark C.; Frost, Christopher J.; Chen, Han-Yi; Babst, Benjamin A.; Harding, Scott A.; Tsai, Chung-Jui

    2013-01-01

    Salicylic acid (SA) has long been implicated in plant responses to oxidative stress. SA overproduction in Arabidopsis thaliana leads to dwarfism, making in planta assessment of SA effects difficult in this model system. We report that transgenic Populus tremula × alba expressing a bacterial SA synthase hyperaccumulated SA and SA conjugates without negative growth consequences. In the absence of stress, endogenously elevated SA elicited widespread metabolic and transcriptional changes that resembled those of wild-type plants exposed to oxidative stress-promoting heat treatments. Potential signaling and oxidative stress markers azelaic and gluconic acids as well as antioxidant chlorogenic acids were strongly coregulated with SA, while soluble sugars and other phenylpropanoids were inversely correlated. Photosynthetic responses to heat were attenuated in SA-overproducing plants. Network analysis identified potential drivers of SA-mediated transcriptome rewiring, including receptor-like kinases and WRKY transcription factors. Orthologs of Arabidopsis SA signaling components NON-EXPRESSOR OF PATHOGENESIS-RELATED GENES1 and thioredoxins were not represented. However, all members of the expanded Populus nucleoredoxin-1 family exhibited increased expression and increased network connectivity in SA-overproducing Populus, suggesting a previously undescribed role in SA-mediated redox regulation. The SA response in Populus involved a reprogramming of carbon uptake and partitioning during stress that is compatible with constitutive chemical defense and sustained growth, contrasting with the SA response in Arabidopsis, which is transient and compromises growth if sustained. PMID:23903318

  2. Increased leaf area dominates carbon flux response to elevated CO2 in stands of Populus deltoides (Bartr.)

    Treesearch

    Ramesh Murthy; Greg Barron-Gafford; Philip M. Dougherty; Victor c. Engels; Katie Grieve; Linda Handley; Christie Klimas; Mark J. Postosnaks; Stanley J. Zarnoch; Jianwei Zhang

    2005-01-01

    We examined the effects of atmospheric vapor pressure deficit (VPD) and soil moisture stress (SMS) on leaf- and stand-level CO2 exchange in model 3-year-old coppiced cottonwood (Populus deltoides Bartr.) plantations using the large-scale, controlled environments of the Biosphere 2 Laboratory. A short-term experiment was imposed...

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

    Treesearch

    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).

  4. Identification of candidate genes in Populus cell wall biosynthesis using text-mining, co-expression network and comparative genomics

    SciTech Connect

    Yang, Xiaohan; Ye, Chuyu; Bisaria, Anjali; Tuskan, Gerald A; Kalluri, Udaya C

    2011-01-01

    Populus is an important bioenergy crop for bioethanol production. A greater understanding of cell wall biosynthesis processes is critical in reducing biomass recalcitrance, a major hindrance in efficient generation of ethanol from lignocellulosic biomass. Here, we report the identification of candidate cell wall biosynthesis genes through the development and application of a novel bioinformatics pipeline. As a first step, via text-mining of PubMed publications, we obtained 121 Arabidopsis genes that had the experimental evidences supporting their involvement in cell wall biosynthesis or remodeling. The 121 genes were then used as bait genes to query an Arabidopsis co-expression database and additional genes were identified as neighbors of the bait genes in the network, increasing the number of genes to 548. The 548 Arabidopsis genes were then used to re-query the Arabidopsis co-expression database and re-construct a network that captured additional network neighbors, expanding to a total of 694 genes. The 694 Arabidopsis genes were computationally divided into 22 clusters. Queries of the Populus genome using the Arabidopsis genes revealed 817 Populus orthologs. Functional analysis of gene ontology and tissue-specific gene expression indicated that these Arabidopsis and Populus genes are high likelihood candidates for functional genomics in relation to cell wall biosynthesis.

  5. Drought-Induced Xylem Dysfunction in Petioles, Branches, and Roots of Populus balsamifera L. and Alnus glutinosa (L.) Gaertn.

    PubMed Central

    Hacke, U.; Sauter, J. J.

    1996-01-01

    Variation in vulnerability to xylem cavitation was measured within individual organs of Populus balsamifera L. and Alnus glutinosa (L.) Gaertn. Cavitation was quantified by three different techniques: (a) measuring acoustic emissions, (b) measuring loss of hydraulic conductance while air-dehydrating a branch, and (c) measuring loss of hydraulic conductance as a function of positive air pressure injected into the xylem. All of these techniques gave similar results. In Populus, petioles were more resistant than branches, and branches were more resistant than roots. This corresponded to the pattern of vessel width: maximum vessel diameter in 1- to 2-year-old roots was 140 [mu]m, compared to 65 and 45 [mu]m in rapidly growing 1-year-old shoots and petioles, respectively. Cavitation in Populus petioles started at a threshold water potential of -1.1 MPa. The lowest leaf water potential observed was -0.9 MPa. In Alnus, there was no relationship between vessel diameter and the cavitation response of a plant organ. Although conduits were narrower in petioles than in branches, petioles were more vulnerable to cavitation. Cavitation in petioles was detected when water potential fell below -1.2 MPa. This value equaled midday leaf water potential in late June. As in Populus, roots were the most vulnerable organ. The significance of different cavitation thresholds in individual plant organs is discussed. PMID:12226296

  6. Economics of Afforestation with Eastern Cottonwood (Populus Deltoides) of Agricultural Land in the Lower Mississippi Alluvial Valley

    Treesearch

    John A. Stanturf; C. Jeffrey Portwood

    1999-01-01

    Higher prices for hardwood stumpage and changes in agricultural policies may favor afforestation on sites in the Lower Mississippi Alluvial Valley (LMAV) which are suitable for Eastern cottonwood (Populus deltoides Bartr.). We examined the potential returns to a landowner growing cottonwood on three soil classes common to the LMAV. We specified the...

  7. Macro- and micro-nutrient concentration in leaf, woody, and root tissue of Populus irrigated with landfill leachate

    Treesearch

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

    2007-01-01

    Landfill leachate offers an opportunity to supply water and plant nutritional benefits at a lower cost than traditional sources. Information about nutrient uptake and distribution into tissues of Populus irrigated with landfill leachate helps increase biomass production along with evaluating the impacts of leachate chemistry on tree health.

  8. Nine-year performance of a variety of Populus taxa on an upland site in western Kentucky

    Treesearch

    Randall J. Rousseau; Joshua P. Adams; David W. Wilkerson

    2013-01-01

    A variety of hybrid poplars have been planted on upland sites throughout the Midwest and Midsouth regions of the United States. Very few of these clones have proven to be worthwhile due to susceptibility to a variety of diseases. Five different Populus taxa were planted on an upland site in western Kentucky as a means of assessing resistance to local...

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

    PubMed Central

    2011-01-01

    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. PMID:21569431

  10. Growth, dry weight yields, and specific gravity of 3-year-old Populus grown under intensive culture.

    Treesearch

    David H. Dawson; J.G Isebrands; John C. Gordon

    1976-01-01

    In a nearly optimal cultural environment, Populus 'Tristis #1' grown for 3 years, planted at 9 by 9 inch spacing produced the equivalent of over 4 tons/acre/year of ovendry wood with specific gravity comparable to native aspen wood. Trees planted at wider spacings yielded less.

  11. Projected and actual biomass production of 2- to 10- year-old intensively cultured Populus 'Tristis # 1'

    Treesearch

    J. Zavitkovski

    1983-01-01

    Intensively cultured plantations of Populus 'Tristis # 1' produce more than 10 mt/ha/year of woody biomass at most spacings as long as they are harvested when mean annual biomass increment (MABI) culminates. In addition, fully stocked plantations produce up to 4.4 mt/ha of leaf litter. Plantations of other poplar clones produce about 30% more woody biomass,...

  12. Field performance of Populus in short-rotation intensive culture plantations in the north-central U.S.

    Treesearch

    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.

  13. Early rooting of dormant hardwood cuttings of Populus: analysis of quantitative genetics and genotype x environment interactions

    Treesearch

    Ronald S., Jr. Zalesny; Don E. Riemenschneider; Richard B. Hall

    2005-01-01

    Rooting of hardwood cuttings is under strong genetic control, although genotype x environment interactions affect selection of promising genotypes. Our objectives were (1) to assess the variation in rooting ability among 21 Populus clones and (2) to examine genotype x environment interactions to refine clonal recommendations. The clones belonged to...

  14. Growth under field conditions affects lignin content and productivity in transgenic Populus trichocarpa with altered lignin biosynthesis

    Treesearch

    Anna T. Stout; Aletta A. Davis; Jean-Christophe Domec; Chenmin Yang; Rui Shi; John S. King

    2014-01-01

    This study evaluated the potential of transgenic Populus trichocarpa with antisense 4CL for reduced total lignin and sense Cald5H for increased S/G ratio in a short rotation woody cropping (SRWC) system for bioethanol production in the Southeast USA. Trees produced from tissue-culture were planted in the Coastal Plain, Piedmont, and Mountain regions of North Carolina,...

  15. Comparative physiology of allopatric Populus species: geographic clines in photosynthesis, height growth, and carbon isotope discrimination in common gardens.

    PubMed

    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.

  16. Photosynthesis of Nuttall oak (Quercus nuttallii Palm.) seedlings interplanted beneath an eastern cottonwood (Populus deltoides Bartr. Ex Marsh.) nurse crop

    Treesearch

    Emile S. Gardiner; Callie J. Schweitzer; John A. Stanturf

    2001-01-01

    An afforestation system which utilizes the pioneer species eastern cottonwood (Populus deltoides Bartr. ex Marsh.) as a nurse for slower growing, disturbance-dependent species is under evaluation as a forest rehabilitation tool on former agricultural land in the Lower Mississippi River Alluvial Valley, USA. The primary objectives...

  17. Effects of light regime and IBA concentration on adventitious rooting of an eastern cottonwood (Populus deltoides) clone

    Treesearch

    Alexander P. Hoffman; Joshua P. Adams; Andrew Nelson

    2016-01-01

    Eastern cottonwood (Populus deltoides) has received a substantial amount of interest from invitro studies within the past decade. The ability to efficiently multiply the stock of established clones such as clone 110412 is a valuable asset for forest endeavors. However, a common problem encountered is initiating adventitious rooting in new micropropagation protocols....

  18. Comparative physiology of allopatric Populus species: geographic clines in photosynthesis, height growth, and carbon isotope discrimination in common gardens

    PubMed Central

    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 (gs) 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 (δ13C) 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. PMID:26236324

  19. Date of shoot collection, genotype, and original shoot position affect early rooting of dormant hardwood cuttings of Populus

    Treesearch

    R. S., Jr. Zalesny; A.H. Wiese

    2006-01-01

    Identifying superior combinations among date of dormant- season shoot collection, genotype, and original shoot position can increase the rooting potential of Populus cuttings. Thus, the objectives of our study were to: 1) evaluate variation among clones in early rooting from hardwood cuttings processed every three weeks from shoots collected...

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

    PubMed

    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.

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

    USGS Publications Warehouse

    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.

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

    PubMed

    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.

  3. Genome-wide identification and characterization of novel lncRNAs in Populus under nitrogen deficiency.

    PubMed

    Chen, Min; Wang, Chenlu; Bao, Hai; Chen, Hui; Wang, Yanwei

    2016-08-01

    Long non-coding RNAs (lncRNAs) have been identified as important regulatory factors of gene expression in eukaryotic species, such as Homo sapiens, Arabidopsis thaliana, and Oryza sativa. However, the systematic identification of potential lncRNAs in trees is comparatively rare. In particular, the characteristics, expression, and regulatory roles of lncRNAs in trees under nutrient stress remain largely unknown. A genome-wide strategy was used in this investigation to identify and characterize novel and low-nitrogen (N)-responsive lncRNAs in Populus tomentosa; 388 unique lncRNA candidates belonging to 380 gene loci were detected and only seven lncRNAs were found to belong to seven conserved non-coding RNA families indicating the majority of P. tomentosa lncRNAs are species-specific. In total, 126 lncRNAs were significantly altered under low-N stress; 8 were repressed, and 118 were induced. Furthermore, 9 and 5 lncRNAs were detected as precursors of 11 known and 14 novel Populus miRNAs, respectively, whereas 4 lncRNAs were targeted by 29 miRNAs belonging to 5 families, including 22 conserved and 7 non-conserved miRNAs. In addition, 15 antisense lncRNAs were identified to be generated from opposite strands of 14 corresponding protein-coding genes. In total, 111 protein-coding genes with regions complementary to 38 lncRNAs were also predicted with some lncRNAs corresponding to multiple genes and vice versa, and their functions were annotated, which further demonstrated the complex regulatory relationship between lncRNAs and protein-coding genes in plants. Moreover, an interaction network among lncRNAs, miRNAs, and mRNAs was investigated. These findings enrich our understanding of lncRNAs in Populus, expand the methods of miRNA identification. Our results present the first global characterization of lncRNAs and their potential target genes in response to nitrogen stress in trees, which provides more information on low-nutrition adaptation mechanisms in woody plants.

  4. Investigating the Relationship Between Liquid Water and Leaf Area in Clonal Populus

    NASA Technical Reports Server (NTRS)

    Roberts, Dar; Brown, K.; Green, R.; Ustin, S.; Hinckley, T.

    1998-01-01

    to increase following a gradient of increasing LAI ranging from grasslands to coniferous forests. In that study, it was observed that forests, which showed little variation in NDVI, showed significant variation in liquid water. In order to test this hypothesis, we analyzed field spectra measured over Populus resprouts of known LAI and monitored changes in liquid water in young Populus stands as they aged over a 4-year time span. The study was conducted in south-central Washington, in a clonal Populus fiber farm owned and operated by Boise-Cascade near the town of Wallula.

  5. High rates of virus-induced gene silencing by tobacco rattle virus in Populus.

    PubMed

    Shen, Zedan; Sun, Jian; Yao, Jun; Wang, Shaojie; Ding, Mingquan; Zhang, Huilong; Qian, Zeyong; Zhao, Nan; Sa, Gang; Zhao, Rui; Shen, Xin; Polle, Andrea; Chen, Shaoliang

    2015-09-01

    Virus-induced gene silencing (VIGS) has been shown to be an effective tool for investigating gene functions in herbaceous plant species, but has rarely been tested in trees. The establishment of a fast and reliable transformation system is especially important for woody plants, many of which are recalcitrant to transformation. In this study, we established a tobacco rattle virus (TRV)-based VIGS system for two Populus species, Populus euphratica and P. × canescens. Here, TRV constructs carrying a 266 bp or a 558 bp fragment of the phytoene desaturase (PDS) gene were Agrobacterium-infiltrated into leaves of the two poplar species. Agrobacterium-mediated delivery of the shorter insert, TRV2-PePDS266, into the host poplars resulted in expected photobleaching in both tree species, but not the longer insert, PePDS558. The efficiency of VIGS was temperature-dependent, increasing by raising the temperature from 18 to 28 °C. The optimized TRV-VIGS system at 28 °C resulted in a high silencing frequency and efficiency up to 65-73 and 83-94%, respectively, in the two tested poplars. Moreover, syringe inoculation of Agrobacterium in 100 mM acetosyringone induced a more efficient silencing in the two poplar species, compared with other agroinfiltration methods, e.g., direct injection, misting and agrodrench. There were plant species-related differences in the response to VIGS because the photobleaching symptoms were more severe in P. × canescens than in P. euphratica. Furthermore, VIGS-treated P. euphratica exhibited a higher recovery rate (50%) after several weeks of the virus infection, compared with TRV-infected P. × canescens plants (20%). Expression stability of reference genes was screened to assess the relative abundance of PePDS mRNA in VIGS-treated P. euphratica and P. × canescens. PeACT7 was stably expressed in P. euphratica and UBQ-L was selected as the most suitable reference gene for P. × canescens using three different

  6. Investigating the Relationship Between Liquid Water and Leaf Area in Clonal Populus

    NASA Technical Reports Server (NTRS)

    Roberts, Dar; Brown, K.; Green, R.; Ustin, S.; Hinckley, T.

    1998-01-01

    to increase following a gradient of increasing LAI ranging from grasslands to coniferous forests. In that study, it was observed that forests, which showed little variation in NDVI, showed significant variation in liquid water. In order to test this hypothesis, we analyzed field spectra measured over Populus resprouts of known LAI and monitored changes in liquid water in young Populus stands as they aged over a 4-year time span. The study was conducted in south-central Washington, in a clonal Populus fiber farm owned and operated by Boise-Cascade near the town of Wallula.

  7. Genome-Scale Discovery of Cell Wall Biosynthesis Genes in Populus (JGI Seventh Annual User Meeting 2012: Genomics of Energy and Environment)

    ScienceCinema

    Muchero, Wellington [Oak Ridge National Laboratory

    2016-07-12

    Wellington Muchero from Oak Ridge National Laboratory gives a talk titled "Discovery of Cell Wall Biosynthesis Genes in Populus" at the JGI 7th Annual Users Meeting: Genomics of Energy & Environment Meeting on March 22, 2012 in Walnut Creek, California.

  8. Genome-Scale Discovery of Cell Wall Biosynthesis Genes in Populus (JGI Seventh Annual User Meeting 2012: Genomics of Energy and Environment)

    SciTech Connect

    Muchero, Wellington

    2012-03-22

    Wellington Muchero from Oak Ridge National Laboratory gives a talk titled "Discovery of Cell Wall Biosynthesis Genes in Populus" at the JGI 7th Annual Users Meeting: Genomics of Energy & Environment Meeting on March 22, 2012 in Walnut Creek, California.

  9. Expression of chloroplastic genes during autumnal senescence in a deciduous tree Populus deltiodes.

    PubMed

    Reddy, M S; Trivedi, P K; Tuli, R; Sane, P V

    1997-10-01

    In Populus deltoides, a deciduous tree, the development on new leaves starts in the month of March, the leaves reach maturity by October and fall by December. Changes in the composition and function of the photosynthetic apparatus were analysed during autumnal senescence. With the progress of senescence, there was an initial increase followed by a decrease in the steady state levels of psbA, psbD/C and psaA/B gene transcripts. Decrease in the steady state level of D1 protein was faster than that of Cytochrome f. The decline in LHCP level was seen only during late senescence. Although the leaves continue to look green and healthy till late November, the electron transport driven by individual photosystems started declining by October end suggesting the onset of senescence.

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

    SciTech Connect

    Evans, Luke M; Slavov, Gancho; Rodgers-Melnick, Eli; Martin, Joel; Ranjan, Priya; Muchero, Wellington; Brunner, Amy M.; Schackwitz, Wendy; Gunter, Lee E; Chen, Jay; Tuskan, Gerald A; Difazio, Stephen P.

    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.

  11. Stable transformation of Populus and incorporation of pest resistance by electric discharge particle acceleration.

    PubMed

    McCown, B H; McCabe, D E; Russell, D R; Robison, D J; Barton, K A; Raffa, K F

    1991-02-01

    Three different target tissues (protoplast-derived cells, nodules, and stems) and two unrelated hybrid genotypes of Populus (P. alba x P. grandidentata 'Crandon' and P. nigra 'Betulifolia' x P. trichocarpa) have been stably transformed by electric discharge particle acceleration using a 18.7 kb plasmid containing NOS-NPT, CaMV 35S-GUS, and CaMV 35S-BT. Four transformed plants of one hybrid genotype, NC5339, containing all 3 genes were recovered and analyzed. Two expressed GUS and one was highly resistant to feeding by 2 lepidopteran pests (the forest tent caterpillar, Malacosoma disstria, and the gypsy moth, Lymantria dispar.) Pretreatment of the target tissues, fine-tuning of the bombardment parameters, and the use of a selection technique employing flooding of the target tissues were important for reliable recovery of transformed plants.

  12. Natural acetylation impacts carbohydrate recovery during deconstruction of Populus trichocarpa wood

    DOE PAGES

    Johnson, Amanda M.; Kim, Hoon; Ralph, John; ...

    2017-02-23

    Significant variation in the inherent degree of acetylation naturally exists in the xylem cell walls of Populus trichocarpa. During pretreatment, endogenous acetate hydrolyzes to acetic acid that can subsequently catalyze the breakdown of poplar wood, increasing the efficiency of biomass pretreatment. Poplar genotypes varying in cell wall composition were pretreated in 0.3% H2SO4 in non-isothermal batch reactors. Acetic acid released from the wood was positively related to sugar release during pretreatment (R ≥ 0.9), and inversely proportional to the lignin content of the poplar wood (R = 0.6). There is significant variation in wood chemistry among P. trichocarpa genotypes. Asmore » a result, this study elucidated patterns of cell wall deconstruction and clearly links carbohydrate solubilization to acetate release. Tailoring biomass feedstocks for acetate release could enhance pretreatment efficiencies.« less

  13. Towards a holistic understanding of the beneficial interactions across the Populus microbiome

    DOE PAGES

    Hacquard, Stéphane; Schadt, Christopher W.

    2014-11-24

    Interactions between trees and microorganisms are extremely complex and the multispecies networks resulting from these associations have consequences for plant growth and productivity. However, a more holistic view is needed to better understand trees as ecosystems and superorganisms, where many interacting species contribute to the overall stability of the system. While much progress has been made on microbial communities associated with individual tree niches and the molecular interactions between model symbiotic partners, there is still a lack of knowledge of the multi-component interactions necessary for holistic ecosystem-level understanding. Finally, we review recent studies in Populus to emphasize the importance ofmore » such holistic efforts across the leaf, stem and rooting zones, and discuss prospects for future research in these important ecosystems.« less

  14. Climate, migration, and the local food security context: Introducing Terra Populus.

    PubMed

    Nawrotzki, Raphael J; Schlak, Allison M; Kugler, Tracy A

    2016-12-01

    Studies investigating the connection between environmental factors and migration are difficult to execute because they require the integration of microdata and spatial information. In this article, we introduce the novel, publically available data extraction system Terra Populus (TerraPop), which was designed to facilitate population-environment studies. We showcase the use of TerraPop by exploring variations in the climate-migration association in Burkina Faso and Senegal based on differences in the local food security context. Food security was approximated using anthropometric indicators of child stunting and wasting derived from Demographic and Health Surveys (DHS) and linked to the TerraPop extract of climate and migration information. We find that an increase in heat waves was associated with a decrease in international migration from Burkina Faso, while excessive precipitation increased international moves from Senegal. Significant interactions reveal that the adverse effects of heat waves and droughts are strongly amplified in highly food insecure Senegalese departments.

  15. Climate, migration, and the local food security context: Introducing Terra Populus

    PubMed Central

    Schlak, Allison M.; Kugler, Tracy A.

    2016-01-01

    Studies investigating the connection between environmental factors and migration are difficult to execute because they require the integration of microdata and spatial information. In this article, we introduce the novel, publically available data extraction system Terra Populus (TerraPop), which was designed to facilitate population-environment studies. We showcase the use of TerraPop by exploring variations in the climate-migration association in Burkina Faso and Senegal based on differences in the local food security context. Food security was approximated using anthropometric indicators of child stunting and wasting derived from Demographic and Health Surveys (DHS) and linked to the TerraPop extract of climate and migration information. We find that an increase in heat waves was associated with a decrease in international migration from Burkina Faso, while excessive precipitation increased international moves from Senegal. Significant interactions reveal that the adverse effects of heat waves and droughts are strongly amplified in highly food insecure Senegalese departments. PMID:27974863

  16. In-situ reduced silver nanoparticles on populus fiber and the catalytic application

    NASA Astrophysics Data System (ADS)

    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.

  17. A Putative PP2C-Encoding Gene Negatively Regulates ABA Signaling in Populus euphratica.

    PubMed

    Chen, Jinhuan; Zhang, Dongzhi; Zhang, Chong; Xia, Xinli; Yin, Weilun; Tian, Qianqian

    2015-01-01

    A PP2C homolog gene was cloned from the drought-treated cDNA library of Populus euphratica. Multiple sequence alignment analysis suggested that the gene is a potential ortholog of HAB1. The expression of this HAB1 ortholog (PeHAB1) was markedly induced by drought and moderately induced by ABA. To characterize its function in ABA signaling, we generated transgenic Arabidopsis thaliana plants overexpressing this gene. Transgenic lines exhibited reduced responses to exogenous ABA and reduced tolerance to drought compared to wide-type lines. Yeast two-hybrid analyses indicated that PeHAB1 could interact with the ABA receptor PYL4 in an ABA-independent manner. Taken together; these results indicated that PeHAB1 is a new negative regulator of ABA responses in poplar.

  18. Biochemical and physiological studies on the effects of senescence leaves of Populus deltoides on Triticum vulgare.

    PubMed

    Khaket, Tejinder Pal; Kumar, Viney; Singh, Jasbir; Dhanda, Suman

    2014-01-01

    Triticum vulgare (Wheat) based products are the major dietary source of food in developing countries. In India, it grows in association with boundary plantations of Populus deltoids (poplar). During winter, poplar enters in dormancy which cause a heavy leaf fall at the time of wheat seed germination. Large number of poplar senescence leaves may adversely affect the wheat. Therefore, the present study was performed to examine the effect of senescence poplar leaves on wheat germ and some other biochemical parameters. Seed's germination rate was determined by measuring root and shoot lengths, percent germination, germination index, and inhibition percentage. Biochemical parameters, namely, pigment, carbohydrate, protein, and phenol content, were estimated. Activities of catalase and polyphenol oxidase which are stress marker enzymes were also measured. Results revealed that germination and other biochemical parameters of wheat were severely affected by senescence poplar leaves even at very low concentration. So, intercropping of poplar along with wheat may be chosen carefully as wheat is the major dietary staple.

  19. Incorporation of 14C-Photosynthate into Protein during Leaf Development in Young Populus Plants 1

    PubMed Central

    Dickmann, Donald I.; Gordon, John C.

    1975-01-01

    Gas exchange and protein metabolism were studied in expanding, mature, and near-senescent leaves of young clonal Populus × euramericana cv. Wisconsin-5 plants. Dark respiration, CO2 evolution in the light, and CO2 compensation concentrations were highest in unexpanded leaves but declined markedly as leaves matured and aged. Net photosynthesis was highest in nearly mature leaves. Fresh weight continued to increase after leaf expansion was complete, whereas soluble protein levels declined. Changes in the distribution of photosynthetically incorporated 14C indicated that a high level of protein synthesis and rapid formation of structural components occurred only in expanding leaves. Protein turnover was slight in expanding leaves but was substantial after leaves were mature. Expanding leaves synthesized predominantly fraction I protein (ribulose diphosphate carboxylase). However, formation of this protein from photosynthate was slight once leaves matured. PMID:16659251

  20. Characterization of a novel, ubiquitous fungal endophyte from the rhizosphere and root endosphere of Populus trees

    DOE PAGES

    Vélez, Jessica M.; Tschaplinski, Timothy J.; Vilgalys, Rytas; ...

    2017-04-07

    Here, we examined variation in growth rate, patterns of nitrogen utilization, and competitive interactions of Atractiellarhizophila isolates from the roots of Populus hosts. Atractiella grew significantly faster on media substituted with inorganic nitrogen sources and slower in the presence of another fungal genus. In order to determine plausible causal mechanisms we used metabolomics to explore competitive interactions between Atractiella strains and Fusarium oxysporum or Leptosphaerulina chartarum. Metabolomic screening of potential microbial inhibitors showed increased levels of glycosides produced in vitro by Atractiella when grown with a different fungal genus, relative to when grown alone. Overall, our results suggest Atractiella ismore » a poor competitor with other fungi via direct routes e.g. faster growth rates, but may utilize chemical interactions and possibly nitrogen sources to defend itself, and niche partition its way to abundance in the plant host root and rhizosphere.« less