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Sample records for hyperaccumulator thlaspi caerulescens1w

  1. Increased glutathione biosynthesis plays a role in nickel tolerance in thlaspi nickel hyperaccumulators.

    PubMed

    Freeman, John L; Persans, Michael W; Nieman, Ken; Albrecht, Carrie; Peer, Wendy; Pickering, Ingrid J; Salt, David E

    2004-08-01

    Worldwide more than 400 plant species are now known that hyperaccumulate various trace metals (Cd, Co, Cu, Mn, Ni, and Zn), metalloids (As) and nonmetals (Se) in their shoots. Of these, almost one-quarter are Brassicaceae family members, including numerous Thlaspi species that hyperaccumulate Ni up to 3% of there shoot dry weight. We observed that concentrations of glutathione, Cys, and O-acetyl-l-serine (OAS), in shoot tissue, are strongly correlated with the ability to hyperaccumulate Ni in various Thlaspi hyperaccumulators collected from serpentine soils, including Thlaspi goesingense, T. oxyceras, and T. rosulare, and nonaccumulator relatives, including T. perfoliatum, T. arvense, and Arabidopsis thaliana. Further analysis of the Austrian Ni hyperaccumulator T. goesingense revealed that the high concentrations of OAS, Cys, and GSH observed in this hyperaccumulator coincide with constitutively high activity of both serine acetyltransferase (SAT) and glutathione reductase. SAT catalyzes the acetylation of l-Ser to produce OAS, which acts as both a key positive regulator of sulfur assimilation and forms the carbon skeleton for Cys biosynthesis. These changes in Cys and GSH metabolism also coincide with the ability of T. goesingense to both hyperaccumulate Ni and resist its damaging oxidative effects. Overproduction of T. goesingense SAT in the nonaccumulator Brassicaceae family member Arabidopsis was found to cause accumulation of OAS, Cys, and glutathione, mimicking the biochemical changes observed in the Ni hyperaccumulators. In these transgenic Arabidopsis, glutathione concentrations strongly correlate with increased resistance to both the growth inhibitory and oxidative stress induced effects of Ni. Taken together, such evidence supports our conclusion that elevated GSH concentrations, driven by constitutively elevated SAT activity, are involved in conferring tolerance to Ni-induced oxidative stress in Thlaspi Ni hyperaccumulators.

  2. Hyperaccumulation of cadmium by hairy roots of Thlaspi caerulescens

    SciTech Connect

    Nedelkoska, T.V.; Doran, P.M.

    2000-03-05

    Hairy roots were used to investigate cadmium uptake by Thlaspi caerulescens, a metal hyperaccumulator plant with potential applications in phytoremediation and phytomining. Experiments were carried out in nutrient media under conditions supporting root growth. Accumulation of Cd in short-term (9-h) experiments varied with initial medium pH and increased after treating the roots with H{sup +}-ATPase inhibitor. The highest equilibrium Cd content measured in T. caerulescens roots was 62,800 {micro}g g{sup {minus}1} dry weight, or 6.3% dry weight, at a liquid Cd concentration of 3,710 ppm. Cd levels in live T. caerulescens roots were 1.5- to 1.7-fold those in hairy roots of nonhyperaccumulator species exposed to the same Cd concentration, but similar to the Cd content of auto-claved T. caerulescens roots. The ability to grow at Cd concentrations of up to 100 ppm clearly distinguished T. caerulescens hairy roots from the nonhyperaccumulators. The specific growth rate of T. caerulescens roots was essentially unaffected by 20 to 50 ppm Cd in the culture medium; in contrast, N. tabacum roots turned dark brown at 20 ppm and growth was negligible. Up to 10,600 {micro}g g{sup {minus}1} dry weight Cd was accumulated by growing T. caerulescens hairy roots. Measurement of Cd levels in while roots and in the cell wall fraction revealed significant differences in the responses of T. caerulescens and N. tabacum roots to 20 ppm Cd. Most metal was transported directly into the symplasm of N. tabacum roots within 3 days of exposure; in contrast, T. caerulescens roots stored virtually all of their Cd in the wall fraction for the first 7 to 10 days. This delay in transmembrane uptake may represent an important defensive strategy against Cd poisoning in T. caerulescens, allowing time for activation of intracellular mechanisms for heavy metal detoxification.

  3. Cadmium leaching from micro-lysimeters planted with the hyperaccumulator Thlaspi caerulescens: experimental findings and modeling.

    PubMed

    Ingwersen, Joachim; Bücherl, Barbara; Neumann, Günter; Streck, Thilo

    2006-01-01

    The use of heavy metal hyperaccumulating plants has the potential to become a promising new technique to remediate contaminated sites. We investigated the role of metal mobilization in the Cd hyperaccumulation of Thlaspi caerulescens (J. & C. Presl, 'Ganges'). In a micro-lysimeter experiment we investigated the dynamics of Cd concentration of leachate as well as Cd removal by plant uptake in four treatments: (i) Control (bare soil), (ii) T. caerulescens, (iii) nonhyperaccumulator Brassica juncea (L.) Czern. ('PI 426308'), and (iv) co-cropping of the hyperaccumulator and nonhyperaccumulator. The experimental findings were analyzed using one- and two-site rate-limited desorption models. Co-cropping of T. caerulescens and B. juncea did not enhance metal uptake by B. juncea. Although Cd uptake of T. caerulescens was 10 times higher than that of B. juncea, the Cd concentration of leachate of the T. caerulescens treatment did not decrease below that of the B. juncea treatment. The Cd depletion in leachate was well reproduced by the two-site rate-limited desorption model. The optimized desorption coefficient was three orders of magnitude higher in the rhizosphere than in the bulk soil. Our results indicate that T. caerulescens accelerates the resupply of Cd from soil pointing to an important role of kinetic desorption in the hyperaccumulation by T. caerulescens.

  4. Zinc ligands in the metal hyperaccumulator Thlaspi caerulescens as determined using X-ray absorption spectroscopy

    SciTech Connect

    Salt, D.E.; Prince, R.C.; Baker, A.J.M.; Raskin, I.; Pickering, I.J.

    1999-03-01

    Using the noninvasive technique of X-ray absorption spectroscopy (XAS), the authors have been able to determine the ligand environment of Zn in different tissues of the Zn-hyperaccumulator Thlaspi caerulescens. The majority of intracellular Zn in roots of T. caerulescens was found to be coordinated with histidine. In the xylem sap Zn was found to be transported mainly as the free hydrated Zn{sup 2+} cation with a smaller proportion coordinated with organic acids. In the shoots, Zn coordination occurred mainly via organic acids, with a smaller proportion present as the hydrated cation and coordinated with histidine and the cell wall. Their data suggest that histidine plays an important role in Zn homeostasis in the roots, whereas organic acids are involved in xylem transport and Zn storage in shoots.

  5. Molecular Dissection of the Role of Histidine in Nickel Hyperaccumulation in Thlaspi goesingense (Hálácsy)1

    PubMed Central

    Persans, Michael W.; Yan, Xiange; Patnoe, Jean-Marc M.L.; Krämer, Ute; Salt, David E.

    1999-01-01

    To understand the role of free histidine (His) in Ni hyperaccumulation in Thlaspi goesingense, we investigated the regulation of His biosynthesis at both the molecular and biochemical levels. Three T. goesingense cDNAs encoding the following His biosynthetic enzymes, ATP phosphoribosyltransferase (THG1, GenBank accession no. AF003347), imidazoleglycerol phosphate dehydratase (THB1, GenBank accession no. AF023140), and histidinol dehydrogenase (THD1, GenBank accession no. AF023141) were isolated by functional complementation of Escherichia coli His auxotrophs. Northern analysis of THG1, THD1, and THB1 gene expression revealed that each gene is expressed in both roots and shoots, but at the concentrations and dosage times of Ni treatment used in this study, these genes failed to show any regulation by Ni. We were also unable to observe any increases in the concentration of free His in root, shoot, or xylem sap of T. goesingense in response to Ni exposure. X-ray absorption spectroscopy of root and shoot tissue from T. goesingense and the non-accumulator species Thlaspi arvense revealed no major differences in the coordination of Ni by His in these tissues. We therefore conclude that the Ni hyperaccumulation phenotype in T. goesingense is not determined by the overproduction of His in response to Ni. PMID:10594099

  6. Colonisation of a Zn, Cd and Pb hyperaccumulator Thlaspi praecox Wulfen with indigenous arbuscular mycorrhizal fungal mixture induces changes in heavy metal and nutrient uptake.

    PubMed

    Vogel-Mikus, Katarina; Pongrac, Paula; Kump, Peter; Necemer, Marijan; Regvar, Marjana

    2006-01-01

    Plants of the Zn, Cd and Pb hyperaccumulator Thlaspi praecox Wulfen (Brassicaceae) inoculated or not with indigenous arbuscular mycorrhizal (AM) fungal mixture were grown in a highly Cd, Zn and Pb contaminated substrate in order to evaluate the functionality of symbiosis and assess the possible impact of AM colonisation on heavy metal uptake and tolerance. The results suggest AM development in the metal hyperaccumulating T. praecox is favoured at elevated nutrient demands, e.g. during the reproductive period. AM colonisation parameters positively correlated with total soil Cd and Pb. Colonised plants showed significantly improved nutrient and a decreased Cd and Zn uptake as revealed by TRXRF, thus confirming the functionality of the symbiosis. Reduced heavy metal uptake, especially at higher soil metal contents, indicates a changed metal tolerance strategy in colonised T. praecox plants. This is to our knowledge the first report on AM colonisation of the Zn, Cd and Pb hyperaccumulator T. praecox in a greenhouse experiment.

  7. Zinc Isotope Fractionation in the Hyperaccumulator Noccaea caerulescens and the Nonaccumulating Plant Thlaspi arvense at Low and High Zn Supply.

    PubMed

    Tang, Ye-Tao; Cloquet, Christophe; Deng, Teng-Hao-Bo; Sterckeman, Thibault; Echevarria, Guillaume; Yang, Wen-Jun; Morel, Jean-Louis; Qiu, Rong-Liang

    2016-08-02

    On the basis of our previous field survey, we postulate that the pattern and degree of zinc (Zn) isotope fractionation in the Zn hyperaccumulator Noccaea caerulescens (J. & C. Presl) F. K. Mey may reflect a relationship between Zn bioavailability and plant uptake strategies. Here, we investigated Zn isotope discrimination during Zn uptake and translocation in N. caerulescens and in a nonaccumulator Thlaspi arvense L. with a contrasting Zn accumulation ability in response to low (Zn-L) and high (Zn-H) Zn supplies. The average isotope fractionations of the N. caerulescens plant as a whole, relative to solution (Δ(66)Znplant-solution), were -0.06 and -0.12‰ at Zn-L-C and Zn-H-C, respectively, indicative of the predominance of a high-affinity (e.g., ZIP transporter proteins) transport across the root cell membrane. For T. arvense, plants were more enriched in light isotopes under Zn-H-A (Δ(66)Znplant-solution = -0.26‰) than under Zn-L-A and N. caerulescens plants, implying that a low-affinity (e.g., ion channel) transport might begin to function in the nonaccumulating plants when external Zn supply increases. Within the root tissues of both species, the apoplast fractions retained up to 30% of Zn mass under Zn-H. Moreover, the highest δ(66)Zn (0.75‰-0.86‰) was found in tightly bound apoplastic Zn, pointing to the strong sequestration in roots (e.g., binding to high-affinity ligands/precipitation with phosphate) when plants suffer from high Zn stress. During translocation, the magnitude of isotope fractionation was significantly greater at Zn-H (Δ(66)Znroot-shoot = 0.79‰) than at Zn-L, indicating that fractionation mechanisms associated with root-shoot translocation might be identical to the two plant species. Hence, we clearly demonstrated that Zn isotope fractionation could provide insight into the internal sequestration mechanisms of roots when plants respond to low and high Zn supplies.

  8. Transcriptional regulation of metal transport genes and mineral nutrition during acclimatization to cadmium and zinc in the Cd/Zn hyperaccumulator, Thlaspi caerulescens (Ganges population).

    PubMed

    Küpper, Hendrik; Kochian, Leon V

    2010-01-01

    We investigated changes in mineral nutrient uptake and cellular expression levels for metal transporter genes in the cadmium (Cd)/zinc (Zn) hyperaccumulator, Thlaspi caerulescens during whole plant and leaf ontogenesis under different long-term treatments with Zn and Cd. Quantitative mRNA in situ hybridization (QISH) revealed that transporter gene expression changes not only dependent on metal nutrition/toxicity, but even more so during plant and leaf development. The main mRNA abundances found were: ZNT1, mature leaves of young plants; ZNT5, young leaves of young plants; MTP1 (= ZTP1 = ZAT), young leaves of both young and mature plants. Surprisingly different cellular expression patterns were found for ZNT1 and ZNT5, both belonging to the ZIP family of transition metal transporters: ZNT1, photosynthetic mesophyll and bundle sheath cells; ZNT5, nonphotosynthetic epidermal metal storage cells and bundle sheath cells. Thus, ZNT1 may function in micronutrient nutrition while ZNT5 may be involved in metal storage associated with hyperaccumulation. Cadmium inhibited the uptake of Zn, iron (Fe) and manganese (Mn), probably by competing for transporters or by interfering with the regulation of transporter gene expression. Cadmium-induced changes in cellular expression for ZNT1, ZNT5 and MTP1 could also be part of plant acclimatization to Cd toxicity. Defence against Cd toxicity involved enhanced uptake of magnesium (Mg), calcium (Ca) and sulphur (S).

  9. Plant response to heavy metal toxicity: comparative study between the hyperaccumulator Thlaspi caerulescens (ecotype Ganges) and nonaccumulator plants: lettuce, radish, and alfalfa.

    PubMed

    Benzarti, Saoussen; Mohri, Shino; Ono, Yoshiro

    2008-10-01

    Thlaspi caerulescens (alpine pennycress) is one of the best-known heavy metal (HM) hyperaccumulating plant species. It exhibits the ability to extract and accumulate various HM at extremely high concentrations. In this hydroponic study, the performance of T. caerulescens (ecotype Ganges) to accumulate Cd, Zn, and Cu was compared with that of three nonaccumulator plants: alfalfa (Medicago sativa), radish (Raphanus sativus), and lettuce (Lactuca sativa). Plants were exposed to the separately dissolved HM salts for 7 days at a wide range of increasing concentrations: 0 (control: 1/5 Hoagland nutrient solution), 0.1, 1, 10, 100, and 1000 microM. The comparative study combined chemical, physiological, and ecotoxicological assessments. Excessive concentrations of HM (100 and 1000 microM) affected plant growth, photosynthesis, and phytoaccumulation efficiency. Root exudation for all plant species was highly and significantly correlated to HM concentration in exposure solutions and proved its importance to counter effect toxicity. T. caerulescens resisted better the phytotoxic effects of Cd and Zn (at 1000 microM each), and translocated them significantly within tissues (366 and 1290 microg g(-1), respectively). At the same HM level, T. caerulescens exhibited lower performances in accumulating Cu when compared with the rest of plant species, mainly alfalfa (298 microg g(-1)). Root elongation inhibition test confirmed the selective aptitude of T. caerulescens to better cope with Cd and Zn toxicities. MetPLATE bioassay showed greater sensitivity to HM toxicity with much lower EC(50) values for beta-galactosidase activity in E. coli. Nevertheless, exaggerated HM concentrations coupled with relatively short exposure time did not allow for an efficient metal phytoextraction thus a significant reduction of ecotoxicity.

  10. Complexation and Toxicity of Copper in Higher Plants. II. Different Mechanisms for Copper versus Cadmium Detoxification in the Copper-Sensitive Cadmium/Zinc Hyperaccumulator Thlaspi caerulescens (Ganges Ecotype)1[OA

    PubMed Central

    Mijovilovich, Ana; Leitenmaier, Barbara; Meyer-Klaucke, Wolfram; Kroneck, Peter M.H.; Götz, Birgit; Küpper, Hendrik

    2009-01-01

    The cadmium/zinc hyperaccumulator Thlaspi caerulescens is sensitive toward copper (Cu) toxicity, which is a problem for phytoremediation of soils with mixed contamination. Cu levels in T. caerulescens grown with 10 μm Cu2+ remained in the nonaccumulator range (<50 ppm), and most individuals were as sensitive toward Cu as the related nonaccumulator Thlaspi fendleri. Obviously, hyperaccumulation and metal resistance are highly metal specific. Cu-induced inhibition of photosynthesis followed the “sun reaction” type of damage, with inhibition of the photosystem II reaction center charge separation and the water-splitting complex. A few individuals of T. caerulescens were more Cu resistant. Compared with Cu-sensitive individuals, they recovered faster from inhibition, at least partially by enhanced repair of chlorophyll-protein complexes but not by exclusion, since the content of Cu in their shoots was increased by about 25%. Extended x-ray absorption fine structure (EXAFS) measurements on frozen-hydrated leaf samples revealed that a large proportion of Cu in T. caerulescens is bound by sulfur ligands. This is in contrast to the known binding environment of cadmium and zinc in the same species, which is dominated by oxygen ligands. Clearly, hyperaccumulators detoxify hyperaccumulated metals differently compared with nonaccumulated metals. Furthermore, strong features in the Cu-EXAFS spectra ascribed to metal-metal contributions were found, in particular in the Cu-resistant specimens. Some of these features may be due to Cu binding to metallothioneins, but a larger proportion seems to result from biomineralization, most likely Cu(II) oxalate and Cu(II) oxides. Additional contributions in the EXAFS spectra indicate complexation of Cu(II) by the nonproteogenic amino acid nicotianamine, which has a very high affinity for Cu(II) as further characterized here. PMID:19692532

  11. Potential use of metal hyperaccumulators

    SciTech Connect

    Chaney, R.; Li, Yin-Ming; Green, C.

    1996-12-31

    Experiments involving biological accumulation of metal contaminants are summarized in the article. The focus is on identification of hyperaccumulating plant species for cadmium and zinc. Two of the studies examined Thlaspi caerulescens (alpine pennycress) as a bioadsorbent; the third study compared different species of Thlaspi. The T. caerulescens accumulated both metals, but with low yields. Other plant species were identified which adsorbed cadmium or zinc, but not both metals.

  12. Facultative hyperaccumulation of heavy metals and metalloids.

    PubMed

    Pollard, A Joseph; Reeves, Roger D; Baker, Alan J M

    2014-03-01

    Approximately 500 species of plants are known to hyperaccumulate heavy metals and metalloids. The majority are obligate metallophytes, species that are restricted to metalliferous soils. However, a smaller but increasing list of plants are "facultative hyperaccumulators" that hyperaccumulate heavy metals when occurring on metalliferous soils, yet also occur commonly on normal, non-metalliferous soils. This paper reviews the biology of facultative hyperaccumulators and the opportunities they provide for ecological and evolutionary research. The existence of facultative hyperaccumulator populations across a wide edaphic range allows intraspecific comparisons of tolerance and uptake physiology. This approach has been used to study zinc and cadmium hyperaccumulation by Noccaea (Thlaspi) caerulescens and Arabidopsis halleri, and it will be instructive to make similar comparisons on species that are distributed even more abundantly on normal soil. Over 90% of known hyperaccumulators occur on serpentine (ultramafic) soil and accumulate nickel, yet there have paradoxically been few experimental studies of facultative nickel hyperaccumulation. Several hypotheses suggested to explain the evolution of hyperaccumulation seem unlikely when most populations of a species occur on normal soil, where plants cannot hyperaccumulate due to low metal availability. In such species, it may be that hyperaccumulation is an ancestral phylogenetic trait or an anomalous manifestation of physiological mechanisms evolved on normal soils, and may or may not have direct adaptive benefits.

  13. Colonization of pennycresses (Thlaspi spp.) of the Brassicaceae by arbuscular mycorrhizal fungi.

    PubMed

    Regvar, Marjana; Vogel, Katarina; Irgel, Nina; Wraber, Tone; Hildebrandt, Ulrich; Wilde, Petra; Bothe, Hermann

    2003-06-01

    Members of the Brassicaceae are generally believed to be non-mycorrhizal. Pennycress (Thlaspi) species of this family from diverse locations in Slovenia, Austria, Italy and Germany were examined for their colonisation by arbuscular mycorrhizal fungi (AMF). Meadow species (T. praecox, T. caerulescens and T. montanum) were sparsely but distinctly colonised, as indicated by the occurrence of intraradical hyphae, vesicles, coils, and occasionally arbuscules. Species from other locations were poorly colonised, but arbuscules were not discernible. The genus Thlaspi comprises several heavy metal hyperaccumulating species (T. caerulescens, T. goesingense, T. calaminare, T. cepaeifolium). All samples collected from heavy metal soils were at best poorly colonized. Thus the chance is small to find a "hypersystem" in phytoremediation consisting of an AM fungus which prevents the uptake of the major part of the heavy metals and of a Thlaspi species which effectively deposits the residual heavy metals inevitably taken up into its vacuoles. In two different PCR approaches, fungal DNA was amplified from most of the Thlaspi roots examined, even from those with a very low incidence of AMF colonization. Sequencing of the 28S- and 18S-rDNA PCR-products revealed that different Thlaspi field samples were colonized by Glomus intraradices and thus by a common AM fungus. However, none of the sequences obtained was identical to any other found in the present study or deposited in the databanks, which might indicate that a species continuum exists in the G. intraradices clade. An effective colonization of Thlaspi by AMF could not be established in greenhouse experiments. Although the data show that Thlaspi can be colonized by AMF, it is doubtful whether an effective symbiosis with the mutual exchange of metabolites is formed by both partners.

  14. Molecular dissection of the cellular mechanisms involved in nickel hyperaccumulation in plants. 1998 annual progress report

    SciTech Connect

    Salt, D.

    1998-06-01

    'Phytoremediation, the use of plants for environmental cleanup of pollutants, including toxic metals, holds the potential to allow the economic restoration of heavy metal and radionuclide contaminated sites. A number of terrestrial plants are known to naturally accumulate high levels of metals in their shoots (1--2% dry weight), and these plants have been termed metal-hyperaccumulators. Clearly, the genetic traits that determine metal-hyperaccumulation offers the potential for the development of practical phytoremediation processes. The long-term objective is to rationally design and generate plants ideally suited for phytoremediation using this unique genetic material. Initially, the strategy will focus on isolating and characterizing the key genetic information needed for expression of the metal-hyperaccumulation phenotype. Recently, histidine has been shown to play a major role in Ni hyperaccumulation. Based on this information the authors propose to investigate, at the molecular level, the role of histidine biosynthesis in Ni hyperaccumulation in Thlaspi goesingense, a Ni hyperaccumulator species.'

  15. Molecular Dissection of the Cellular Mechanisms Involved in Nickel Hyperaccumulation in Plants

    SciTech Connect

    Salt, David E.

    1999-06-01

    Phytoremediation, the use of plants for environmental cleanup of pollutants, including toxic metals, holds the potential to allow the economic restoration of heavy metal and radionuclide contaminated sites. A number of terrestrial plants are known to naturally accumulate high levels of metals in their shoots (1-2% dry weight), and these plants have been termed metal-hyperaccumulators. Clearly, the genetic traits that determines metal-hyperaccumulation offers the potential for the development of practical phytoremediation processes. Our long-term objective is to rationally design and generate plants ideally suited for phytoremediation using this unique genetic material. Initially, our strategy will focus on isolating and characterizing the key genetic information needed for expression of the metal-hyperaccumulation phenotype. Recently, histidine has been shown to play a major role in Ni hyperaccumulation. Based on this information we propose to investigate, at the molecular level, the role of histidine biosynthesis in Ni hyperaccumulation in Thlaspi goesingense, a Ni hyperaccumulator species. We will clone key genes involved in histidine biosynthesis. We will characterize their transcriptional and post transcriptional regulation by histidine, Ni. We will determine if any of these genes are essential and sufficient for Ni hyperaccumulation by their expression in the non-hyperaccumulator Arabidopsis thaliana.

  16. A native Zn/Cd transporting P1B ATPase from natural overexpression in a hyperaccumulator plant reveals post-translational processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    TcHMA4 is a P1B-type ATPase that is highly expressed in the Cd/Zn hyperaccumulator plant Thlaspi caerulescens and contains a C-terminal 9-histidine repeat. After isolation from roots, we purified TcHMA4 protein via metal affinity chromatography. The purified protein exhibited Cd- and Zn activated AT...

  17. Proteomics of Thlaspi caerulescens accessions and an inter-accession cross segregating for zinc accumulation

    PubMed Central

    Tuomainen, Marjo; Tervahauta, Arja; Hassinen, Viivi; Schat, Henk; Koistinen, Kaisa M.; Lehesranta, Satu; Rantalainen, Kimmo; Häyrinen, Jukka; Auriola, Seppo; Anttonen, Mikko; Kärenlampi, Sirpa

    2010-01-01

    Metal hyperaccumulator plants have previously been characterized by transcriptomics, but reports on other profiling techniques are scarce. Protein profiles of Thlaspi caerulescens accessions La Calamine (LC) and Lellingen (LE) and lines derived from an LC×LE cross were examined here to determine the co-segregation of protein expression with the level of zinc (Zn) hyperaccumulation. Although hydrophobic proteins such as membrane transporters are not disclosed, this approach has the potential to reveal other proteins important for the Zn hyperaccumulation trait. Plants were exposed to metals. Proteins were separated using two-dimensional electrophoresis and those showing differences among accessions, lines or metal exposures were subjected to mass-spectrometric analysis for identification. Crossing decreased the number of different proteins in the lines compared with the parents, more so in the shoots than in the roots, but the frequencies of Zn-responsive proteins were about the same in the accessions and the selection lines. This supports the finding that the Zn accumulation traits are mainly determined by the root and that Zn accumulation itself is not the reason for the co-segregation. This study demonstrates that crossing accessions with contrasting Zn accumulation traits is a potent tool to investigate the mechanisms behind metal hyperaccumulation. Four tentatively identified root proteins showed co-segregation with high or low Zn accumulation: manganese superoxide dismutase, glutathione S-transferase, S-formyl glutathione hydrolase, and translation elongation factor 5A-2. However, these proteins may not be the direct determinants of Zn accumulation. The role of these and other tentatively identified proteins in Zn accumulation and tolerance is discussed. PMID:20048332

  18. Nickel and zinc isotope fractionation in hyperaccumulating and nonaccumulating plants.

    PubMed

    Deng, Teng-Hao-Bo; Cloquet, Christophe; Tang, Ye-Tao; Sterckeman, Thibault; Echevarria, Guillaume; Estrade, Nicolas; Morel, Jean-Louis; Qiu, Rong-Liang

    2014-10-21

    Until now, there has been little data on the isotope fractionation of nickel (Ni) in higher plants and how this can be affected by plant Ni and zinc (Zn) homeostasis. A hydroponic cultivation was conducted to investigate the isotope fractionation of Ni and Zn during plant uptake and translocation processes. The nonaccumulator Thlaspi arvense, the Ni hyperaccumulator Alyssum murale and the Ni and Zn hyperaccumulator Noccaea caerulescens were grown in low (2 μM) and high (50 μM) Ni and Zn solutions. Results showed that plants were inclined to absorb light Ni isotopes, presumably due to the functioning of low-affinity transport systems across root cell membrane. The Ni isotope fractionation between plant and solution was greater in the hyperaccumulators grown in low Zn treatments (Δ(60)Ni(plant-solution) = -0.90 to -0.63‰) than that in the nonaccumulator T. arvense (Δ(60)Ni(plant-solution) = -0.21‰), thus indicating a greater permeability of the low-affinity transport system in hyperaccumulators. Light isotope enrichment of Zn was observed in most of the plants (Δ(66)Zn(plant-solution) = -0.23 to -0.10‰), but to a lesser extent than for Ni. The rapid uptake of Zn on the root surfaces caused concentration gradients, which induced ion diffusion in the rhizosphere and could result in light Zn isotope enrichment in the hyperaccumulator N. caerulescens. In high Zn treatment, Zn could compete with Ni during the uptake process, which reduced Ni concentration in plants and decreased the extent of Ni isotope fractionation (Δ(60)Ni(plant-solution) = -0.11 to -0.07‰), indicating that plants might take up Ni through a low-affinity transport system of Zn. We propose that isotope composition analysis for transition elements could become an empirical tool to study plant physiological processes.

  19. Molecular dissection of the cellular mechanisms involved in nickel hyperaccumulation. 1997 annual progress report

    SciTech Connect

    Salt, D.E.

    1997-10-28

    'Phytoremediation, the use of plants for environmental cleanup of pollutants, including toxic metals, holds the potential to allow the economic restoration of heavy metal and radionuclide contaminated sites. A number of terrestrial plants are known to naturally accumulate high levels of metals in their shoots (1--2% dry weight), and these plants have been termed metal-hyperaccumulators. Clearly, the genetic traits that determine metal-hyperaccumulation offers the potential for the development of practical phytoremediation processes. The long-term objective is to rationally design and generate plants ideally suited for phytoremediation using this unique genetic material. Initially, the strategy will focus on isolating and characterizing the key genetic information needed for expression of the metal-hyperaccumulation phenotype. Recently, histidine has been shown to play a major role in Ni hyperaccumulation. Based on this information the authors propose to investigate, at the molecular level, the role of histidine biosynthesis in Ni hyperaccumuIation in Thlaspi goesingense, a Ni hyperaccumulator species.'

  20. Zn, Cd and Pb accumulation and arbuscular mycorrhizal colonisation of pennycress Thlaspi praecox Wulf. (Brassicaceae) from the vicinity of a lead mine and smelter in Slovenia.

    PubMed

    Vogel-Mikus, Katarina; Drobne, Damjana; Regvar, Marjana

    2005-01-01

    Significant hyperaccumulation of Zn, Cd and Pb in field samples of Thlaspi praecox Wulf. collected from a heavy metal polluted area in Slovenia was found, with maximal shoot concentrations of 14,590 mg kg(-1) Zn, 5960 mg kg(-1) Cd and 3500 mg kg(-1) Pb. Shoot/root ratios of 9.6 for Zn and 5.6 for Cd show that the metals were preferentially transported to the shoots. Shoot bioaccumulation factors exceeded total soil Cd levels 75-fold and total soil Zn levels 20-fold, further supporting the hyperaccumulation of Cd and Zn. Eighty percent of Pb was retained in roots, thus indicating exclusion as a tolerance strategy for Pb. Low level colonisation with arbuscular mycorrhizal fungi (AMF) of a Paris type was observed at the polluted site, whereas at the non-polluted site Arum type colonisation was more common. To our knowledge this is the first report of Cd hyperaccumulation and AMF colonisation in metal hyperaccumulating T. praecox.

  1. Molecular dissection of the role of histidine in nickel hyperaccumulation in Thalspi goesingense (Halacsy)

    SciTech Connect

    Persans, M.W.; Yan, X.; Patnoe, J.M.M.L.; Kraemer, U.; Salt, D.E.

    1999-12-01

    To understand the role of free histidine (His) in Ni hyperaccumulation in Thlaspi goesingense, the authors investigated the regulation of His biosynthesis at both the molecular and biochemical levels. Three T. goesingense cDNAs encoding the following His biosynthetic enzymes, ATP phosphoribosyltransferase, imidazoleglycerol phosphate dehydratase, and histidinol dehydrogenase, were isolated by functional complementation of Escherichia coli His autotrophs. Northern analysis of THJG1, THD1, and THB1 gene expression revealed that each gene is expressed in both roots and shoots, but at the concentrations and dosage times of Ni treatment used in this study, these genes failed to show any regulation by Ni. The authors were also unable to observe any increases in the concentration of free His in root, shoot, or xylem sap of T. goesingense in response to Ni exposure. X-ray absorption spectroscopy of root and shoot tissue from T. goesingense and the non-accumulator species Thlaspi reverse revealed no major differences in the coordination of Ni by His in these tissues. They therefore conclude that the Ni hyperaccumulation phenotype in T. goesingense is not determined by the overproduction of His in response to Ni.

  2. Impact of Metal Pollution and Thlaspi caerulescens Growth on Soil Microbial Communities▿

    PubMed Central

    Epelde, Lur; Becerril, José M.; Kowalchuk, George A.; Deng, Ye; Zhou, Jizhong; Garbisu, Carlos

    2010-01-01

    Soil microorganisms drive critical functions in plant-soil systems. As such, various microbial properties have been proposed as indicators of soil functioning, making them potentially useful in evaluating the recovery of polluted soils via phytoremediation strategies. To evaluate microbial responses to metal phytoextraction using hyperaccumulators, a microcosm experiment was carried out to study the impacts of Zn and/or Cd pollution and Thlaspi caerulescens growth on key soil microbial properties: basal respiration; substrate-induced respiration (SIR); bacterial community structure as assessed by PCR-denaturing gradient gel electrophoresis (DGGE); community sizes of total bacteria, ammonia-oxidizing bacteria, and chitin-degrading bacteria as assessed by quantitative PCR (Q-PCR); and functional gene distributions as determined by functional gene arrays (GeoChip). T. caerulescens proved to be suitable for Zn and Cd phytoextraction: shoots accumulated up to 8,211 and 1,763 mg kg−1 (dry weight [DW]) of Zn and Cd, respectively. In general, Zn pollution led to decreased levels of basal respiration and ammonia-oxidizing bacteria, while T. caerulescens growth increased the values of substrate-induced respiration (SIR) and total bacteria. In soils polluted with 1,000 mg Zn kg−1 and 250 mg Cd kg−1 (DW), soil bacterial community profiles and the distribution of microbial functional genes were most affected by the presence of metals. Metal-polluted and planted soils had the highest percentage of unique genes detected via the GeoChip (35%). It was possible to track microbial responses to planting with T. caerulescens and to gain insight into the effects of metal pollution on soilborne microbial communities. PMID:20935131

  3. Response of antioxidative enzymes and apoplastic bypass transport in Thlaspi caerulescens and Raphanus sativus to cadmium stress.

    PubMed

    Benzarti, Saoussen; Hamdi, Helmi; Mohri, Shino; Ono, Yoshiro

    2010-01-01

    A hydroponics experiment using hyperaccumulator Thlaspi caerulescens (alpine pennycress) and non-specific accumulator Raphanus sativus (common radish) was conducted to investigate the short-term effect of increasing Cd concentrations (0, 25, 50, 75, 100 microM) on metal uptake, chlorophyll content, antioxidative enzymes, and apoplastic bypass flow. As expected, T. caerulescens generally showed better resistance to metal stress, which was reflected by higher Cd accumulation within plant tissues with no signs of chlorosis, or wilt. Glutathione reductase (GR) and superoxide dismutase (SOD) activities in fresh leaves were monitored as the plant metal-detoxifying response. In general, both plant species exhibited an increase trend of GR activity before declining at 100 microM likely due to excessive levels of phytotoxic Cd. SOD activity exhibited almost a similar variation pattern to GR and decreased also at 100 microM Cd. For both plant species, fluorescent PTS uptake (8-hydroxy-1,3,6-pyrenetrisulphonic acid) increased significantly with metal level in exposure solutions indicating that Cd has a comparable effect to drought or salinity in terms of the gain of relative importance in apoplastic bypass transport under such stress conditions.

  4. Registration of Elizabeth Thlaspi arvense L. (Pennycress) with improved non-dormant traits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elizabeth Pennycress (Thlaspi arvense L.) germplasm (Reg. No. GPxxxxx, PI 677360) was publicly released by the USDA, Agricultural Research Service in 2016 for the improvement of thlaspi germplasm. Elizabeth was developed by four generations of mass selection based on the germination response of fres...

  5. Nickel, Zn and Cd localisation in seeds of metal hyperaccumulators using μ-PIXE spectroscopy

    NASA Astrophysics Data System (ADS)

    Kachenko, Anthony G.; Bhatia, Naveen P.; Siegele, Rainer; Walsh, Kerry B.; Singh, Balwant

    2009-06-01

    Metal hyperaccumulators are a rare group of plant species that accumulate exceptionally high concentrations of metals in above ground tissues without showing symptoms of phytotoxicity. Quantitative localisation of the accumulated metals in seed tissues is of considerable interest to help understand the eco-physiology of these unique plant species. We investigated the spatial localisation of metals within seeds of Ni hyperaccumulating Hybanthus floribundus subsp. adpressus, H. floribundus subsp. floribundus and Pimelea leptospermoides and dual-metal (Cd and Zn) hyperaccumulating Thlaspi caerulescens using quantitative micro-proton induced X-ray emission (μ-PIXE) spectroscopy. Intact seeds were hand-sectioned, sandwiched between Formvar films and irradiated using the 3 MeV high energy heavy ion microprobe at ANSTO. Elemental maps of whole H. floribundus subsp. adpressus seeds showed an average Ni concentration of 5.1 × 10 3 mg kg -1 dry weight (DW) with highest Ni concentration in cotyledonary tissues (7.6 × 10 3 mg kg -1 DW), followed by the embryonic axis (4.4 × 10 3 mg kg -1 DW). Nickel concentration in whole H. floribundus subsp. floribundus seeds was 3.5 × 10 2 mg kg -1 DW without a clear pattern of Ni localisation. The average Ni concentration in whole P. leptospermoides seeds was 2.6 × 10 2 mg kg -1 DW, and Ni was preferentially localised in the embryonic axis (4.3 × 10 2 mg kg -1 DW). In T. caerulescens, Cd concentrations were similar in cotyledon (4.5 × 10 3 mg kg -1 DW) and embryonic axis (3.3 × 10 3 mg kg -1 DW) tissues, whereas Zn was highest in cotyledonary tissues (1.5 × 10 3 mg kg -1 DW). In all species, the presence of the accumulated metal within the cotyledonary and embryonic axis tissues indicates that the accumulated metal was able to move apoplastically within the seed.

  6. Composition and functional properties of protein recovered from pennycreess (Thlaspi arvense) press cake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress (Thlaspi arvense L.) seed oil is being considered as alternative feedstock for biodiesel production. If the pennycress-based biodiesel venture is successful, then the seed protein (more than 20% content) could become a major co-product of the process. This study compared two methods for e...

  7. Enrichment of erucic acid from pennycress (Thlaspi arvense L.) seed oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress (Thlaspi arvense) is a winter annual that has a wide geographic distribution and a growth habitat that makes it suitable for an off-season rotation between corn and soybeans in much of the Midwestern United States. Pennycress seed contains 36% oil with 36.6% erucic acid content. There are...

  8. Emergence of field pennycress (Thlaspi arvense L.): Comparison of two accessions and modelling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many weed species are becoming rare due to intense agricultural management, which leads to a decrease of biodiversity in agroecosystems. Cultivating some of these species for their oilseed content may help preserve them while profiting agronomically. Thlaspi arvense is one of these species with pote...

  9. Early planting dates maximize winter annual field pennycress (Thlaspi arvense L.) yield and oil content

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress (Thlaspi arvense L.), a common weed species in North America, has received attention in recent years as a potential oilseed feedstock for biofuel production. However, little is known about best practices for its production as a managed crop. The objective of this study was to determine op...

  10. Extraction, composition and functional properties of pennycress (Thlaspi arvense L.) press cake protein

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study compared two methods for extracting the protein in pennycress (Thlaspi arvense L.) press cake and determined the composition and functional properties of the protein products. Proteins in pennycress press cake were extracted by using the conventional alkali solubilization-acid precipitati...

  11. Preparation, composition and functional properties of pennycress (Thlaspi arvense L.) seed protein isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study evaluated two methods, saline extraction (SE) and conventional acid precipitation (AP), to recover proteins from pennycress (Thlaspi arvense L.) seed meal. SE was done using 0.1 M NaCl at 50ºC while AP involved alkaline extraction (pH 10) first followed by protein precipitation at pH 4. C...

  12. Genome Structure of the Heavy Metal Hyperaccumulator Noccaea caerulescens and Its Stability on Metalliferous and Nonmetalliferous Soils1[OPEN

    PubMed Central

    Mandáková, Terezie; Singh, Vasantika; Krämer, Ute; Lysak, Martin A.

    2015-01-01

    Noccaea caerulescens (formerly known as Thlaspi caerulescens), an extremophile heavy metal hyperaccumulator model plant in the Brassicaceae family, is a morphologically and phenotypically diverse species exhibiting metal tolerance and leaf accumulation of zinc, cadmium, and nickel. Here, we provide a detailed genome structure of the approximately 267-Mb N. caerulescens genome, which has descended from seven chromosomes of the ancestral proto-Calepineae Karyotype (n = 7) through an unusually high number of pericentric inversions. Genome analysis in two other related species, Noccaea jankae and Raparia bulbosa, showed that all three species, and thus probably the entire Coluteocarpeae tribe, have descended from the proto-Calepineae Karyotype. All three analyzed species share the chromosome structure of six out of seven chromosomes and an unusually high metal accumulation in leaves, which remains moderate in N. jankae and R. bulbosa and is extreme in N. caerulescens. Among these species, N. caerulescens has the most derived karyotype, with species-specific inversions on chromosome NC6, which grouped onto its bottom arm functionally related genes of zinc and iron metal homeostasis comprising the major candidate genes NICOTIANAMINE SYNTHASE2 and ZINC-INDUCED FACILITATOR-LIKE1. Concurrently, copper and organellar metal homeostasis genes, which are functionally unrelated to the extreme traits characteristic of N. caerulescens, were grouped onto the top arm of NC6. Compared with Arabidopsis thaliana, more distal chromosomal positions in N. caerulescens were enriched among more highly expressed metal homeostasis genes but not among other groups of genes. Thus, chromosome rearrangements could have facilitated the evolution of enhanced metal homeostasis gene expression, a known hallmark of metal hyperaccumulation. PMID:26195571

  13. A native Zn/Cd pumping P(1B) ATPase from natural overexpression in a hyperaccumulator plant.

    PubMed

    Parameswaran, Aravind; Leitenmaier, Barbara; Yang, Mingjie; Kroneck, Peter M H; Welte, Wolfram; Lutz, Gabriela; Papoyan, Ashot; Kochian, Leon V; Küpper, Hendrik

    2007-11-09

    We report here the first purification of a P(1B) type ATPase, a group of transporters that occurs in bacteria, plants and animals incl. humans, from a eukaryotic organism in native state. TcHMA4 is a P(1B) type ATPase that is highly expressed in the Cd/Zn hyperaccumulator plant Thlaspi caerulescens and contains a C-terminal 9-histidine repeat. After isolation from roots, we purified TcHMA4 protein via metal affinity chromatography. The purified protein exhibited Cd- and Zn-activated ATPase activity after reconstitution into lipid vesicles, showing that it was in its native state. Gels of crude root extract and of the purified protein revealed TcHMA4-specific bands of about 50 and 60kDa, respectively, while the TcHMA4 mRNA predicts a single protein with a size of 128kDa. This indicates the occurrence of post-translational processing; the properties of the two bands were characterised by their activity and binding properties.

  14. Prospecting for hyperaccumulators of trace elements: a review.

    PubMed

    Krzciuk, Karina; Gałuszka, Agnieszka

    2015-01-01

    Specific plant species that can take up and accumulate abnormally high concentrations of elements in their aboveground tissues are referred to as "hyperaccumulators". The use of this term is justified in the case of enormous element-binding capacity of plants growing in their natural habitats and showing no toxicity symptoms. An increasing interest in the study of hyperaccumulators results from their potential applications in environmental biotechnology (phytoremediation, phytomining) and their emerging role in nanotechnology. The highest number of plant species with confirmed hyperaccumulative properties has been reported for hyperaccumulators of nickel, cadmium, zinc, manganese, arsenic and selenium. More limited data exist for plants accumulating other elements, including common pollutants (chromium, lead and boron) or elements of commercial value, such as copper, gold and rare earth elements. Different approaches have been used for the study of hyperaccumulators - geobotanical, chemical, biochemical and genetic. The chemical approach is the most important in screening for new hyperaccumulators. This article presents and critically reviews current trends in new hyperaccumulator research, emphasizing analytical methodology that is applied in identification of new hyperaccumulators of trace elements and its future perspectives.

  15. Effects of arsenic on nitrogen metabolism in arsenic hyperaccumulator and non-hyperaccumulator ferns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the effects of arsenic on the in vitro activities of the enzymes (nitrate reductase and nitrite reductase) involved in nitrate metabolism in the roots, rhizomes, and fronds of two four-month old fern plants, Pteris vittata, an arsenic-hyperaccumulator, and Pteris ensiformis, ...

  16. Hyperaccumulators, arbuscular mycorrhizal fungi and stress of heavy metals.

    PubMed

    Miransari, Mohammad

    2011-01-01

    Use of plants, with hyperaccumulating ability or in association with soil microbes including the symbiotic fungi, arbuscular mycorrhiza (AM), are among the most common biological methods of treating heavy metals in soil. Both hyperaccumulating plants and AM fungi have some unique abilities, which make them suitable to treat heavy metals. Hyperaccumulator plants have some genes, being expressed at the time of heavy metal pollution, and can accordingly localize high concentration of heavy metals to their tissues, without showing the toxicity symptoms. A key solution to the issue of heavy metal pollution may be the proper integration of hyperaccumulator plants and AM fungi. The interactions between the soil microbes and the host plant can also be important for the treatment of soils polluted with heavy metals.

  17. Growth environment but not seed position on the parent plant affect seed germination of two Thlaspi arvense L. populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thlaspi arvense L. is a common weed found in most temperate regions throughout the world that also shows excellent potential for domestication as an oilseed crop. The complexity of T. arvense seed dormancy presently makes it difficult to manage as a weed or oilseed crop. Therefore, a better understa...

  18. Effects of oil extraction on functional properties of protein in pennycress (Thlaspi arvense) seed and press cake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current interest in pennycress (Thlaspi arvense) comes from its seed oil, which is being evaluated for biodiesel production. The seed also has notable protein content (33% db). The effects of oil processing conditions on functionality of pennycress seed proteins were determined to identify potential...

  19. [Determination of sinigrin in semen Thlaspi from Sichuan and Tibet using near infrared diffuse reflectance spectroscopy].

    PubMed

    Wang, Lei-Lei; Chen, Cong; Zhou, Min; Wang, Jian-Zhong; Luo, Xia; Huang, Guo; Ye, Li-Ming

    2009-10-01

    The objective of the present study was to develop a method for the determination of sinigrin in semen Thlaspi from Sichuan using near infrared diffuse reflectance spectroscopy. Near infrared spectra (NIR) in the region of 7,502.1-5,446.2 cm(-1) were recorded for the 246 semen Thlaspi samples containing sinigrin in the content of 1.962%-3.917%. Calibration models were established using the PLS (partial least squares). Different spectra pretreatment methods were compared. The study showed that spectral information can be extracted thoroughly by minimum and maximum normalization pretreatment methods. In this calibration model, the correlation coefficient (R2) was 0.9280, the SEC (standard deviation of the calibration sets) was 0.314 and the SEP (standard deviation of the prediction sets) was 0.388. Results indicated that near infrared diffuse reflectance spectroscopy method can be used to rapidly analyze the valid component in traditional Chinese medicine, and also can be used in the quality control of traditional Chinese medicine.

  20. Effects of selenium hyperaccumulation on plant-plant interactions: evidence for elemental allelopathy?

    PubMed

    El Mehdawi, Ali F; Quinn, Colin F; Pilon-Smits, Elizabeth A H

    2011-07-01

    • Few studies have investigated plant-plant interactions involving hyperaccumulator plants. Here, we investigated the effect of selenium (Se) hyperaccumulation on neighboring plants. • Soil and litter Se concentrations were determined around the hyperaccumulators Astragalus bisulcatus and Stanleya pinnata and around the nonhyperaccumulators Medicago sativa and Helianthus pumilus. We also compared surrounding vegetative cover, species composition and Se concentration in two plant species (Artemisia ludoviciana and Symphyotrichum ericoides) growing either close to or far from Se hyperaccumulators. Then, Arabidopsis thaliana germination and growth were compared on soils collected next to the hyperaccumulators and the nonhyperaccumulators. • Soil collected around hyperaccumulators contained more Se (up to 266 mg Se kg(-1) ) than soil collected around nonhyperaccumulators. Vegetative ground cover was 10% lower around Se hyperaccumulators compared with nonhyperaccumulators. The Se concentration was higher in neighboring species A. ludoviciana and S. ericoides when growing close to, compared with far from, Se hyperaccumulators. A. thaliana showed reduced germination and growth, and higher Se accumulation, when grown on soil collected around Se hyperaccumulators compared with soil collected around nonaccumulators. • In conclusion, Se hyperaccumulators may increase the surrounding soil Se concentration (phytoenrichment). The enhanced soil Se contents around hyperaccumulators can impair the growth of Se-sensitive plant species, pointing to a possible role of Se hyperaccumulation in elemental allelopathy.

  1. The apoplasmic pathway via the root apex and lateral roots contributes to Cd hyperaccumulation in the hyperaccumulator Sedum alfredii.

    PubMed

    Tao, Qi; Jupa, Radek; Luo, Jipeng; Lux, Alexander; Kováč, Ján; Wen, Yue; Zhou, Yimei; Jan, Japenga; Liang, Yongchao; Li, Tingqiang

    2016-12-16

    Although the significance of apoplasmic barriers in roots with regards to the uptake of toxic elements is generally known, the contribution of apoplasmic bypasses (ABs) to cadmium (Cd) hyperaccumulation is little understood. Here, we employed a combination of stable isotopic tracer techniques, an ABs tracer, hydraulic measurements, suberin lamellae staining, metabolic inhibitors, and antitranspirants to investigate and quantify the impact of the ABs on translocation of Cd to the xylem in roots of a hyperaccumulating (H) ecotype and a non-hyperaccumulating (NH) ecotype of Sedum alfredii In the H ecotype, the Cd content in the xylem sap was proportional to hydrostatic pressure, which was attributed to pressure-driven flow via the ABs. The contribution of the ABs to Cd transportation to the xylem was dependent on the Cd concentration applied to the H ecotype (up to 37% at the highest concentration used). Cd-treated H ecotype roots showed significantly higher hydraulic conductance compared with the NH ecotype (76 vs 52 × 10(-8) m s(-1)MPa(-1)), which is in accordance with less extensive suberization due to reduced expression of suberin-related genes. The main entry sites of apoplasmically transported Cd were localized in the root apexes and lateral roots of the H ecotype, where suberin lamellae were not well developed. These findings highlight the significance of the apoplasmic bypass in Cd hyperaccumulation in hyperaccumulating ecotypes of S. alfredii.

  2. Comparison of Biological Activities of Gibberellins and Gibberellin-Precursors Native to Thlaspi arvense L. 1

    PubMed Central

    Metzger, James D.

    1990-01-01

    Field pennycress (Thlaspi arvense L.) is a winter annual weed with a cold requirement for stem elongation and flowering. The relative abilities of several native gibberellins (GAs) and GA-precursors to elicit stem growth were compared. Of the eight compounds tested, gibberellin A1, (GA1), GA9, and GA20 caused stem growth in noninduced (no cold treatment) plants. No stem growth was observed in plants treated with ent-kaurene, ent-kaurenol, ent-kaurenoic acid, GA53, or GA8. Moreover, of the biologically active compounds, GA9 was the most active followed closely by GA1. In thermoinduced plants (4-week cold treatment at 6°C) that were continuously treated with 2-chlorocholine chloride to reduce endogenous GA production, GA9 was the most biologically active compound. However, the three kaurenoid GA precursors also promoted stem growth in thermoinduced plants, and were almost as active as GA20. No such increase in activity was observed for either GA[unk] or GA53. The results are discussed in relation to thermoinductive regulation of GA metabolism and its significance to the initiation of stem growth in field pennycress. It is proposed that thermoinduction results in increased conversion of ent-kaurenoic acid to GAs through the C-13 desoxy pathway and that GA9 is the endogenous mediator of thermoinduced stem growth in field pennycress. PMID:16667681

  3. Hyperaccumulation, complexation and distribution of nickel in Sebertia acuminata.

    PubMed

    Sagner, S; Kneer, R; Wanner, G; Cosson, J P; Deus-Neumann, B; Zenk, M H

    1998-02-01

    The nickel content in different parts of the hyperaccumulating tree Sebertia acuminata was analysed by atomic absorption spectroscopy. Nickel was found to be mainly located in laticifers. The total nickel content of a single mature tree was estimated to be 37 kg. By gel filtration and NMR spectroscopy, citric acid was unequivocally identified as counter ion for about 40% of this metal present. Nitrate was assumed to be a further partner for a complete ionic balance. Phytochelatins were not found to be involved in nickel detoxification in Sebertia. The localization of nickel complexes inside the laticifers was demonstrated by light microscopy as well as by scanning electron microscopy in combination with an EDX system for the analysis of elements. A repellent effect of the plant sap was observed on the fruit fly Drosophila melanogaster indicating that in hyperaccumulating plants nickel functions as an agent to prevent predation.

  4. Selenium-tolerant diamondback moth disarms hyperaccumulator plantdefense

    SciTech Connect

    Freeman, J.L.; Quinn, C.F.; Marcus, M.A.; Fakra, S.; Pilon-Smits,E.A.H.

    2006-11-20

    Background Some plants hyperaccumulate the toxic element selenium (Se) to extreme levels, up to 1% of dry weight. The function of this intriguing phenomenon is obscure. Results Here, we show that the Se in the hyperaccumulator prince's plume (Stanleya pinnata) protects it from caterpillar herbivory because of deterrence and toxicity. In its natural habitat, however, a newly discovered variety of the invasive diamondback moth (Plutella xylostella) has disarmed this elemental defense. It thrives on plants containing highly toxic Se levels and shows no oviposition or feeding deterrence, in contrast to related varieties. Interestingly, a Se-tolerant wasp (Diadegma insulare) was found to parasitize the tolerant moth. The insect's Se tolerance mechanism was revealed by X-ray absorption spectroscopy and liquid chromatography--mass spectroscopy, which showed that the Se-tolerant moth and its parasite both accumulate methylselenocysteine, the same form found in the hyperaccumulator plant, whereas related sensitive moths accumulate selenocysteine. The latter is toxic because of its nonspecific incorporation into proteins. Indeed, the Se-tolerant diamondback moth incorporated less Se into protein. Additionally, the tolerant variety sequestered Se in distinct abdominal areas, potentially involved in detoxification and larval defense to predators. Conclusions Although Se hyperaccumulation protects plants from herbivory by some invertebrates, it can give rise to the evolution of unique Se-tolerant herbivores and thus provide a portal for Se into the local ecosystem. In a broader context, this study provides insight into the possible ecological implications of using Se-enriched crops as a source of anti-carcinogenic selenocompounds and for the remediation of Se-polluted environments.

  5. Metabolite fingerprinting of pennycress (Thlaspi arvense L.) embryos to assess active pathways during oil synthesis

    PubMed Central

    Tsogtbaatar, Enkhtuul; Cocuron, Jean-Christophe; Sonera, Marcos Corchado; Alonso, Ana Paula

    2015-01-01

    Pennycress (Thlaspi arvense L.), a plant naturalized to North America, accumulates high levels of erucic acid in its seeds, which makes it a promising biodiesel and industrial crop. The main carbon sinks in pennycress embryos were found to be proteins, fatty acids, and cell wall, which respectively represented 38.5, 33.2, and 27.0% of the biomass at 21 days after pollination. Erucic acid reached a maximum of 36% of the total fatty acids. Together these results indicate that total oil and erucic acid contents could be increased to boost the economic competitiveness of this crop. Understanding the biochemical basis of oil synthesis in pennycress embryos is therefore timely and relevant to guide future breeding and/or metabolic engineering efforts. For this purpose, a combination of metabolomics approaches was conducted to assess the active biochemical pathways during oil synthesis. First, gas chromatography–mass spectrometry (GC-MS) profiling of intracellular metabolites highlighted three main families of compounds: organic acids, amino acids, and sugars/sugar alcohols. Secondly, these intermediates were quantified in developing pennycress embryos by liquid chromatography–tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring mode. Finally, partitional clustering analysis grouped the intracellular metabolites that shared a similar pattern of accumulation over time into eight clusters. This study underlined that: (i) sucrose might be stored rather than cleaved into hexoses; (ii) glucose and glutamine would be the main sources of carbon and nitrogen, respectively; and (iii) glycolysis, the oxidative pentose phosphate pathway, the tricarboxylic acid cycle, and the Calvin cycle were active in developing pennycress embryos. PMID:25711705

  6. Metabolite fingerprinting of pennycress (Thlaspi arvense L.) embryos to assess active pathways during oil synthesis

    DOE PAGES

    Tsogtbaatar, Enkhtuul; Cocuron, Jean -Christophe; Sonera, Marcos Corchado; ...

    2015-02-22

    Pennycress (Thlaspi arvense L.), a plant naturalized to North America, accumulates high levels of erucic acid in its seeds, which makes it a promising biodiesel and industrial crop. The main carbon sinks in pennycress embryos were found to be proteins, fatty acids, and cell wall, which respectively represented 38.5, 33.2, and 27.0% of the biomass at 21 days after pollination. Erucic acid reached a maximum of 36% of the total fatty acids. Together these results indicate that total oil and erucic acid contents could be increased to boost the economic competitiveness of this crop. Understanding the biochemical basis of oilmore » synthesis in pennycress embryos is therefore timely and relevant to guide future breeding and/or metabolic engineering efforts. For this purpose, a combination of metabolomics approaches was conducted to assess the active biochemical pathways during oil synthesis. First, gas chromatography-mass spectrometry (GC-MS) profiling of intracellular metabolites highlighted three main families of compounds: organic acids, amino acids, and sugars/sugar alcohols. Secondly, these intermediates were quantified in developing pennycress embryos by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring mode. Finally, partitional clustering analysis grouped the intracellular metabolites that shared a similar pattern of accumulation over time into eight clusters. In conclusion, this study underlined that: (i) sucrose might be stored rather than cleaved into hexoses; (ii) glucose and glutamine would be the main sources of carbon and nitrogen, respectively; and (iii) glycolysis, the oxidative pentose phosphate pathway, the tricarboxylic acid cycle, and the Calvin cycle were active in developing pennycress embryos.« less

  7. Metabolite fingerprinting of pennycress (Thlaspi arvense L.) embryos to assess active pathways during oil synthesis.

    PubMed

    Tsogtbaatar, Enkhtuul; Cocuron, Jean-Christophe; Sonera, Marcos Corchado; Alonso, Ana Paula

    2015-07-01

    Pennycress (Thlaspi arvense L.), a plant naturalized to North America, accumulates high levels of erucic acid in its seeds, which makes it a promising biodiesel and industrial crop. The main carbon sinks in pennycress embryos were found to be proteins, fatty acids, and cell wall, which respectively represented 38.5, 33.2, and 27.0% of the biomass at 21 days after pollination. Erucic acid reached a maximum of 36% of the total fatty acids. Together these results indicate that total oil and erucic acid contents could be increased to boost the economic competitiveness of this crop. Understanding the biochemical basis of oil synthesis in pennycress embryos is therefore timely and relevant to guide future breeding and/or metabolic engineering efforts. For this purpose, a combination of metabolomics approaches was conducted to assess the active biochemical pathways during oil synthesis. First, gas chromatography-mass spectrometry (GC-MS) profiling of intracellular metabolites highlighted three main families of compounds: organic acids, amino acids, and sugars/sugar alcohols. Secondly, these intermediates were quantified in developing pennycress embryos by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring mode. Finally, partitional clustering analysis grouped the intracellular metabolites that shared a similar pattern of accumulation over time into eight clusters. This study underlined that: (i) sucrose might be stored rather than cleaved into hexoses; (ii) glucose and glutamine would be the main sources of carbon and nitrogen, respectively; and (iii) glycolysis, the oxidative pentose phosphate pathway, the tricarboxylic acid cycle, and the Calvin cycle were active in developing pennycress embryos.

  8. Effects of cold-pressing and seed cooking on functional properties of protein in pennycress (Thlaspi arvense L.) seed and press cakes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current interest in pennycress (Thlaspi arvense L.) comes from its seed oil, which is being evaluated for biofuel production. The seed also has notable protein content (27% moisture-free, oil-free basis). The effects of oil processing conditions on functionality of pennycress seed proteins were dete...

  9. Preparation and fuel properties of field pennycress (Thlaspi arvense) seed oil ethyl esters and blends with ultra-low sulfur diesel fuel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field pennycress (Thlaspi arvense L.) is a widely distributed winter annual with high seed oil content (36%) and is suitable as an off-season rotational crop in the Midwestern U.S. Erucic [(13Z)-docosenoic] acid (36.2%) is the most abundant constituent in the oil, with unsaturated and very long chai...

  10. Molybdenum accumulation, tolerance and molybdenum-selenium-sulfur interactions in Astragalus selenium hyperaccumulator and nonaccumulator species.

    PubMed

    DeTar, Rachael Ann; Alford, Élan R; Pilon-Smits, Elizabeth A H

    2015-07-01

    Some species hyperaccumulate selenium (Se) upwards of 0.1% of dry weight. This study addressed whether Se hyperaccumulators also accumulate and tolerate more molybdenum (Mo). A field survey revealed on average 2-fold higher Mo levels in three hyperaccumulator Astragali compared to three nonaccumulator Astragali, which were not significantly different. Next, a controlled study was performed where hyperaccumulators Astragalus racemosus and Astragalus bisulcatus were compared with nonaccumulators Astragalus drummondii and Astragalus convallarius for Mo accumulation and tolerance, alone or in the presence of Se. When grown on agar media with 0, 12, 24 or 48 mg L(-1) molybdate and/or 0, 1.6 or 3.2 mg L(-1) selenate, all species decreased in biomass with increasing Mo supply. Selenium did not impact biomass at the supplied levels. All Astragali accumulated Mo upwards of 0.1% of dry weight. Selenium levels were up to 0.08% in Astragalus racemosus and 0.04% Se in the other species. Overall, there was no correlation between Se hyperaccumulation and Mo accumulation capacity. However, the hyperaccumulators and nonaccumulators differed in some respects. While none of the species had a higher tissue Mo to sulfur (S) ratio than the growth medium, nonaccumulators had a higher Mo/S ratio than hyperaccumulators. Also, while molybdate and selenate reduced S accumulation in nonaccumulators, it did not in hyperaccumulators. Furthermore, A. racemosus had a higher Se/S ratio than its medium, while the other species did not. Additionally, Mo and Se treatment affected S levels in nonaccumulators, but not in hyperaccumulators. In conclusion, there is no evidence of a link between Se and Mo accumulation and tolerance in Astragalus. Sulfate transporters in hyperaccumulating Astragali appear to have higher sulfate specificity over other oxyanions, compared to nonaccumulators, and A. racemosus may have a transporter with enhanced selenate specificity relative to sulfate or molybdate.

  11. Nickel biopathways in tropical nickel hyperaccumulating trees from Sabah (Malaysia)

    PubMed Central

    van der Ent, Antony; Callahan, Damien L.; Noller, Barry N.; Mesjasz-Przybylowicz, Jolanta; Przybylowicz, Wojciech J.; Barnabas, Alban; Harris, Hugh H.

    2017-01-01

    The extraordinary level of accumulation of nickel (Ni) in hyperaccumulator plants is a consequence of specific metal sequestering and transport mechanisms, and knowledge of these processes is critical for advancing an understanding of transition element metabolic regulation in these plants. The Ni biopathways were elucidated in three plant species, Phyllanthus balgooyi, Phyllanthus securinegioides (Phyllanthaceae) and Rinorea bengalensis (Violaceae), that occur in Sabah (Malaysia) on the Island of Borneo. This study showed that Ni is mainly concentrated in the phloem in roots and stems (up to 16.9% Ni in phloem sap in Phyllanthus balgooyi) in all three species. However, the species differ in their leaves – in P. balgooyi the highest Ni concentration is in the phloem, but in P. securinegioides and R. bengalensis in the epidermis and in the spongy mesophyll (R. bengalensis). The chemical speciation of Ni2+ does not substantially differ between the species nor between the plant tissues and transport fluids, and is unambiguously associated with citrate. This study combines ion microbeam (PIXE and RBS) and metabolomics techniques (GC-MS, LC-MS) with synchrotron methods (XAS) to overcome the drawbacks of the individual techniques to quantitatively determine Ni distribution and Ni2+ chemical speciation in hyperaccumulator plants. PMID:28205587

  12. Prosopis pubescens (screw bean mesquite) seedlings are hyperaccumulators of copper.

    PubMed

    Zappala, Marian N; Ellzey, Joanne T; Bader, Julia; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge

    2013-08-01

    Due to health reasons, toxic metals must be removed from soils contaminated by mine tailings and smelter activities. The phytoremediation potential of Prosopis pubescens (screw bean mesquite) was examined by use of inductively-coupled plasma optical emission spectroscopy. Transmission electron microscopy was used to observe ultrastructural changes of parenchymal cells of leaves in the presence of copper. Elemental analysis was used to localize copper within leaves. A 600-ppm copper sulfate exposure to seedlings for 24 days resulted in 31,000 ppm copper in roots, 17,000 ppm in stems, 11,000 in cotyledons and 20 ppm in the true leaves. For a plant to be considered a hyperaccumulator, the plant must accumulate a leaf-to-root ratio <1. Screw bean mesquite exposed to copper had a leaf-to-root ratio of 0.355 when cotyledons were included. We showed that P. pubescens grown in soil is a hyperaccumulator of copper. We recommend that this plant should be field tested.

  13. Tissue fractions of cadmium in two hyperaccumulating Jerusalem artichoke genotypes.

    PubMed

    Long, Xiaohua; Ni, Ni; Liu, Zhaopu; Rengel, Zed; Jiang, Xin; Shao, Hongbo

    2014-01-01

    In order to investigate the mechanisms in two Jerusalem artichoke (Helianthus tuberosus L.) genotypes that hyperaccumulate Cd, a sand-culture experiment was carried out to characterize fractionation of Cd in tissue of Cd-hyperaccumulating genotypes NY2 and NY5. The sequential extractants were: 80% v/v ethanol (FE), deionized water (FW), 1 M NaCl (FNaCl), 2% v/v acetic acid (FAcet), and 0.6 M HCl (FHCl). After 20 days of treatments, NY5 had greater plant biomass and greater Cd accumulation in tissues than NY2. In both genotypes the FNaCl fraction was the highest in roots and stems, whereas the FAcet and FHCl fractions were the highest in leaves. With an increase in Cd concentration in the culture solution, the content of every Cd fraction also increased. The FW and FNaCl ratios in roots were lower in NY5 than in NY2, while the amount of other Cd forms was higher. It implied that, in high accumulator, namely, NY5, the complex of insoluble phosphate tends to be shaped more easily which was much better for Cd accumulation. Besides, translocation from plasma to vacuole after combination with protein may be one of the main mechanisms in Cd-accumulator Jerusalem artichoke genotypes.

  14. Nickel biopathways in tropical nickel hyperaccumulating trees from Sabah (Malaysia)

    NASA Astrophysics Data System (ADS)

    van der Ent, Antony; Callahan, Damien L.; Noller, Barry N.; Mesjasz-Przybylowicz, Jolanta; Przybylowicz, Wojciech J.; Barnabas, Alban; Harris, Hugh H.

    2017-02-01

    The extraordinary level of accumulation of nickel (Ni) in hyperaccumulator plants is a consequence of specific metal sequestering and transport mechanisms, and knowledge of these processes is critical for advancing an understanding of transition element metabolic regulation in these plants. The Ni biopathways were elucidated in three plant species, Phyllanthus balgooyi, Phyllanthus securinegioides (Phyllanthaceae) and Rinorea bengalensis (Violaceae), that occur in Sabah (Malaysia) on the Island of Borneo. This study showed that Ni is mainly concentrated in the phloem in roots and stems (up to 16.9% Ni in phloem sap in Phyllanthus balgooyi) in all three species. However, the species differ in their leaves – in P. balgooyi the highest Ni concentration is in the phloem, but in P. securinegioides and R. bengalensis in the epidermis and in the spongy mesophyll (R. bengalensis). The chemical speciation of Ni2+ does not substantially differ between the species nor between the plant tissues and transport fluids, and is unambiguously associated with citrate. This study combines ion microbeam (PIXE and RBS) and metabolomics techniques (GC-MS, LC-MS) with synchrotron methods (XAS) to overcome the drawbacks of the individual techniques to quantitatively determine Ni distribution and Ni2+ chemical speciation in hyperaccumulator plants.

  15. Nickel biopathways in tropical nickel hyperaccumulating trees from Sabah (Malaysia).

    PubMed

    van der Ent, Antony; Callahan, Damien L; Noller, Barry N; Mesjasz-Przybylowicz, Jolanta; Przybylowicz, Wojciech J; Barnabas, Alban; Harris, Hugh H

    2017-02-16

    The extraordinary level of accumulation of nickel (Ni) in hyperaccumulator plants is a consequence of specific metal sequestering and transport mechanisms, and knowledge of these processes is critical for advancing an understanding of transition element metabolic regulation in these plants. The Ni biopathways were elucidated in three plant species, Phyllanthus balgooyi, Phyllanthus securinegioides (Phyllanthaceae) and Rinorea bengalensis (Violaceae), that occur in Sabah (Malaysia) on the Island of Borneo. This study showed that Ni is mainly concentrated in the phloem in roots and stems (up to 16.9% Ni in phloem sap in Phyllanthus balgooyi) in all three species. However, the species differ in their leaves - in P. balgooyi the highest Ni concentration is in the phloem, but in P. securinegioides and R. bengalensis in the epidermis and in the spongy mesophyll (R. bengalensis). The chemical speciation of Ni(2+) does not substantially differ between the species nor between the plant tissues and transport fluids, and is unambiguously associated with citrate. This study combines ion microbeam (PIXE and RBS) and metabolomics techniques (GC-MS, LC-MS) with synchrotron methods (XAS) to overcome the drawbacks of the individual techniques to quantitatively determine Ni distribution and Ni(2+) chemical speciation in hyperaccumulator plants.

  16. Genetic and Molecular Dissection of Arsenic Hyperaccumulation in the fern Pteris vittata.

    SciTech Connect

    Jo Ann Banks; David Salt

    2008-04-04

    Pteris vittata is a fern that is extraordinary in its ability to tolerate hyperaccumulate high levels of arsenic (As). The goals of the proposed research, to identify the genes that are necessary for As hyperaccumulation in P. vittata using molecular and genetic approaches and to understand the physiology of arsenic uptake and distribution in the living plant, were accomplished during the funding period. The genes that have been identified may ultimately enable the engineering or selection of other plants capable of As hyperaccumulation. This is important for the phytoremediation of arsenic-contaminated soils in areas where P. vittata cannot grow.

  17. Molecular Dissection of The Cellular Mechanisms Involved In Nickel Hyperaccumulation in Plants

    SciTech Connect

    David E. Salt

    2002-04-08

    Hyperaccumulator plant species are able to accumulate between 1-5% of their biomass as metal. However, these plants are often small, slow growing, and do not produce a high biomass. Phytoextraction, a cost-effective, in situ, plant based approach to soil remediation takes advantage of the remarkable ability of hyperaccumulating plants to concentrate metals from the soil and accumulate them in their harvestable, above-ground tissues. However, to make use of the valuable genetic resources identified in metal hyperaccumulating species, it will be necessary to transfer this material to high biomass rapidly growing crop plants. These plants would then be ideally suited to the phytoremediation process, having the ability to produce large amount of metal-rich plant biomass for rapid harvest and soil cleanup. Although progress is being made in understanding the genetic basis of metal hyperaccumulation a more complete understanding will be necessary before we can take full advantage of the genetic potential of these plants.

  18. Evolutionary lineages of nickel hyperaccumulation and systematics in European Alysseae (Brassicaceae): evidence from nrDNA sequence data

    PubMed Central

    Cecchi, Lorenzo; Gabbrielli, Roberto; Arnetoli, Miluscia; Gonnelli, Cristina; Hasko, Agim; Selvi, Federico

    2010-01-01

    Background and Aims Nickel (Ni) hyperaccumulation is a rare form of physiological specialization shared by a small number of angiosperms growing on ultramafic soils. The evolutionary patterns of this feature among European members of tribe Alysseae (Brassicaceae) are investigated using a phylogenetic approach to assess relationships among Ni hyperaccumulators at the genus, species and below-species level. Methods Internal transcribed spacer (ITS) sequences were generated for multiple accessions of Alysseae. Phylogenetic trees were obtained for the genera of the tribe and Alyssum sect. Odontarrhena. All accessions and additional herbarium material were tested for Ni hyperaccumulation with the dimethylglyoxime colorimetric method. Key Results Molecular data strongly support the poorly known hyperaccumulator endemic Leptoplax (Peltaria) emarginata as sister to hyperaccumulator species of Bornmuellera within Alysseae. This is contrary to current assumptions of affinity between L. emarginata and the non-hyperaccumulator Peltaria in Thlaspideae. The lineage Bornmuellera–Leptoplax is, in turn, sister to the two non-hyperaccumulator Mediterranean endemics Ptilotrichum rupestre and P. cyclocarpum. Low ITS sequence variation was found within the monophyletic Alyssum sect. Odontarrhena and especially in A. murale sensu lato. Nickel hyperaccumulation was not monophyletic in any of three main clades retrieved, each consisting of hyperaccumulators and non-hyperaccumulators of different geographical origin. Conclusions Nickel hyperaccumulation in Alysseae has a double origin, but it did not evolve in Thlaspideae. In Bornmuellera–Leptoplax it represents an early synapomorphy inherited from an ancestor shared with the calcicolous, sister clade of Mediterranean Ptilotrichum. In Alyssum sect. Odontarrhena it has multiple origins even within the three European clades recognized. Lack of geographical cohesion suggests that accumulation ability has been lost or gained over the

  19. Phylogeography of Thlaspi arvense (Brassicaceae) in China Inferred from Chloroplast and Nuclear DNA Sequences and Ecological Niche Modeling

    PubMed Central

    An, Miao; Zeng, Liyan; Zhang, Ticao; Zhong, Yang

    2015-01-01

    Thlaspi arvense is a well-known annual farmland weed with worldwide distribution, which can be found from sea level to above 4000 m high on the Qinghai-Tibetan Plateau (QTP). In this paper, a phylogeographic history of T. arvense including 19 populations from China was inferred by using three chloroplast (cp) DNA segments (trnL-trnF, rpl32-trnL and rps16) and one nuclear (n) DNA segment (Fe-regulated transporter-like protein, ZIP). A total of 11 chloroplast haplotypes and six nuclear alleles were identified, and haplotypes unique to the QTP were recognized (C4, C5, C7 and N4). On the basis of molecular dating, haplotypes C4, C5 and C7 have separated from others around 1.58 Ma for cpDNA, which corresponds to the QTP uplift. In addition, this article suggests that the T. arvense populations in China are a mixture of diverged subpopulations as inferred by hT/vT test (hT ≤ vT, cpDNA) and positive Tajima’s D values (1.87, 0.05 < p < 0.10 for cpDNA and 3.37, p < 0.01 for nDNA). Multimodality mismatch distribution curves and a relatively large shared area of suitable environmental conditions between the Last Glacial Maximum (LGM) as well as the present time recognized by MaxEnt software reject the sudden expansion population model. PMID:26110380

  20. The crystal structure of the thiocyanate-forming protein from Thlaspi arvense, a kelch protein involved in glucosinolate breakdown.

    PubMed

    Gumz, Frauke; Krausze, Joern; Eisenschmidt, Daniela; Backenköhler, Anita; Barleben, Leif; Brandt, Wolfgang; Wittstock, Ute

    2015-09-01

    Kelch repeat-containing proteins are involved in diverse cellular processes, but only a small subset of plant kelch proteins has been functionally characterized. Thiocyanate-forming protein (TFP) from field-penny cress, Thlaspi arvense (Brassicaceae), is a representative of specifier proteins, a group of kelch proteins involved in plant specialized metabolism. As components of the glucosinolate-myrosinase system of the Brassicaceae, specifier proteins determine the profile of bioactive products formed when plant tissue is disrupted and glucosinolates are hydrolyzed by myrosinases. Here, we describe the crystal structure of TaTFP at a resolution of 1.4 Å. TaTFP crystallized as homodimer. Each monomer forms a six-blade β-propeller with a wide "top" and a narrower "bottom" opening with distinct strand-connecting loops protruding far beyond the lower propeller surface. Molecular modeling and mutational analysis identified residues for glucosinolate aglucone and Fe(2+) cofactor binding within these loops. As the first experimentally determined structure of a plant kelch protein, the crystal structure of TaTFP not only enables more detailed mechanistic studies on glucosinolate breakdown product formation, but also provides a new basis for research on the diverse roles and mechanisms of other kelch proteins in plants.

  1. A draft genome of field pennycress (Thlaspi arvense) provides tools for the domestication of a new winter biofuel crop

    PubMed Central

    Dorn, Kevin M.; Fankhauser, Johnathon D.; Wyse, Donald L.; Marks, M. David

    2015-01-01

    Field pennycress (Thlaspi arvense L.) is being domesticated as a new winter cover crop and biofuel species for the Midwestern United States that can be double-cropped between corn and soybeans. A genome sequence will enable the use of new technologies to make improvements in pennycress. To generate a draft genome, a hybrid sequencing approach was used to generate 47 Gb of DNA sequencing reads from both the Illumina and PacBio platforms. These reads were used to assemble 6,768 genomic scaffolds. The draft genome was annotated using the MAKER pipeline, which identified 27,390 predicted protein-coding genes, with almost all of these predicted peptides having significant sequence similarity to Arabidopsis proteins. A comprehensive analysis of pennycress gene homologues involved in glucosinolate biosynthesis, metabolism, and transport pathways revealed high sequence conservation compared with other Brassicaceae species, and helps validate the assembly of the pennycress gene space in this draft genome. Additional comparative genomic analyses indicate that the knowledge gained from years of basic Brassicaceae research will serve as a powerful tool for identifying gene targets whose manipulation can be predicted to result in improvements for pennycress. PMID:25632110

  2. The bacterial rhizobiome of hyperaccumulators: future perspectives based on omics analysis and advanced microscopy

    PubMed Central

    Visioli, Giovanna; D'Egidio, Sara; Sanangelantoni, Anna M.

    2015-01-01

    Hyperaccumulators are plants that can extract heavy metal ions from the soil and translocate those ions to the shoots, where they are sequestered and detoxified. Hyperaccumulation depends not only on the availability of mobilized metal ions in the soil, but also on the enhanced activity of metal transporters and metal chelators which may be provided by the plant or its associated microbes. The rhizobiome is captured by plant root exudates from the complex microbial community in the soil, and may colonize the root surface or infiltrate the root cortex. This community can increase the root surface area by inducing hairy root proliferation. It may also increase the solubility of metals in the rhizosphere and promote the uptake of soluble metals by the plant. The bacterial rhizobiome, a subset of specialized microorganisms that colonize the plant rhizosphere and endosphere, makes an important contribution to the hyperaccumulator phenotype. In this review, we discuss classic and more recent tools that are used to study the interactions between hyperaccumulators and the bacterial rhizobiome, and consider future perspectives based on the use of omics analysis and microscopy to study plant metabolism in the context of metal accumulation. Recent data suggest that metal-resistant bacteria isolated from the hyperaccumulator rhizosphere and endosphere could be useful in applications such as phytoextraction and phytoremediation, although more research is required to determine whether such properties can be transferred successfully to non-accumulator species. PMID:25709609

  3. A nonpathogenic Fusarium oxysporum strain enhances phytoextraction of heavy metals by the hyperaccumulator Sedum alfredii Hance.

    PubMed

    Zhang, Xincheng; Lin, Li; Chen, Mingyue; Zhu, Zhiqiang; Yang, Weidong; Chen, Bao; Yang, Xiaoe; An, Qianli

    2012-08-30

    Low biomass and shallow root systems limit the application of heavy metal phytoextraction by hyperaccumulators. Plant growth-promoting microbes may enhance hyperaccumulators'phytoextraction. A heavy metal-resistant fungus belonged to the Fusarium oxysporum complex was isolated from the Zn/Cd co-hyperaccumulator Sedum alfredii Hance grown in a Pb/Zn mined area. This Fusarium fungus was not pathogenic to plants but promoted host growth. Hydroponic experiments showed that 500 μM Zn(2+) or 50 μM Cd(2+) combined with the fungus increased root length, branches, and surface areas, enhanced nutrient uptake and chlorophyll synthesis, leading to more vigorous hyperaccumulators with greater root systems. Soil experiments showed that the fungus increased root and shoot biomass and S. alfredii-mediated heavy metal availabilities, uptake, translocation or concentrations, and thus increased phytoextraction of Zn (144% and 44%), Cd (139% and 55%), Pb (84% and 85%) and Cu (63% and 77%) from the original Pb/Zn mined soil and a multi-metal contaminated paddy soil. Together, the nonpathogenic Fusarium fungus was able to increase S. alfredii root systems and function, metal availability and accumulation, plant biomass, and thus phytoextraction efficiency. This study showed a great application potential for culturable indigenous fungi other than symbiotic mycorrhizas to enhance the phytoextraction by hyperaccumulators.

  4. Selenium hyperaccumulation - Astragalus bisulcatus, Cardamine hupingshanensis and Stanleya pinnata - may be useful for agromining selenium-rich soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selenium hyperaccumulator plants like Stanleya pinnata, Astragalus bisulcatus and the newly discovered Se-accumulator Cardamine hupingshanensis may play an important role in the Se cycle from soil to plant to human in China. Se-hyperaccumulators can be used for agromining or for phytoremediation of ...

  5. Transient Influx of nickel in root mitochondria modulates organic acid and reactive oxygen species production in nickel hyperaccumulator Alyssum murale.

    PubMed

    Agrawal, Bhavana; Czymmek, Kirk J; Sparks, Donald L; Bais, Harsh P

    2013-03-08

    Mitochondria are important targets of metal toxicity and are also vital for maintaining metal homeostasis. Here, we examined the potential role of mitochondria in homeostasis of nickel in the roots of nickel hyperaccumulator plant Alyssum murale. We evaluated the biochemical basis of nickel tolerance by comparing the role of mitochondria in closely related nickel hyperaccumulator A. murale and non-accumulator Alyssum montanum. Evidence is presented for the rapid and transient influx of nickel in root mitochondria of nickel hyperaccumulator A. murale. In an early response to nickel treatment, substantial nickel influx was observed in mitochondria prior to sequestration in vacuoles in the roots of hyperaccumulator A. murale compared with non-accumulator A. montanum. In addition, the mitochondrial Krebs cycle was modulated to increase synthesis of malic acid and citric acid involvement in nickel hyperaccumulation. Furthermore, malic acid, which is reported to form a complex with nickel in hyperaccumulators, was also found to reduce the reactive oxygen species generation induced by nickel. We propose that the interaction of nickel with mitochondria is imperative in the early steps of nickel uptake in nickel hyperaccumulator plants. Initial uptake of nickel in roots results in biochemical responses in the root mitochondria indicating its vital role in homeostasis of nickel ions in hyperaccumulation.

  6. Interactive effects of Cd and PAHs on contaminants removal from co-contaminated soil planted with hyperaccumulator plant Sedum alfredii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil contamination by multiple organic and inorganic contaminants is common but its remediation by hyperaccumulator plants is rarely reported. The growth of a cadmium (Cd) hyperaccumulator Sedum alfredii and removal of contaminants from Cd and polycyclic aromatic hydrocarbons(PAHs) co-contaminated s...

  7. The arsenic hyperaccumulating Pteris vittata expresses two arsenate reductases

    PubMed Central

    Cesaro, Patrizia; Cattaneo, Chiara; Bona, Elisa; Berta, Graziella; Cavaletto, Maria

    2015-01-01

    Enzymatic reduction of arsenate to arsenite is the first known step in arsenate metabolism in all organisms. Although the presence of one mRNA arsenate reductase (PvACR2) has been characterized in gametophytes of P. vittata, no arsenate reductase protein has been directly observed in this arsenic hyperaccumulating fern, yet. In order to assess the possible presence of arsenate reductase in P. vittata, two recombinant proteins, ACR2-His6 and Trx-His6-S-Pv2.5–8 were prepared in Escherichia coli, purified and used to produce polyclonal antibodies. The presence of these two enzymes was evaluated by qRT-PCR, immunoblotting and direct MS analysis. Enzymatic activity was detected in crude extracts. For the first time we detected and identified two arsenate reductase proteins (PvACR2 and Pv2.5–8) in sporophytes and gametophytes of P. vittata. Despite an increase of the mRNA levels for both proteins in roots, no difference was observed at the protein level after arsenic treatment. Overall, our data demonstrate the constitutive protein expression of PvACR2 and Pv2.5–8 in P. vittata tissues and propose their specific role in the complex metabolic network of arsenic reduction. PMID:26412036

  8. The arsenic hyperaccumulating Pteris vittata expresses two arsenate reductases.

    PubMed

    Cesaro, Patrizia; Cattaneo, Chiara; Bona, Elisa; Berta, Graziella; Cavaletto, Maria

    2015-09-28

    Enzymatic reduction of arsenate to arsenite is the first known step in arsenate metabolism in all organisms. Although the presence of one mRNA arsenate reductase (PvACR2) has been characterized in gametophytes of P. vittata, no arsenate reductase protein has been directly observed in this arsenic hyperaccumulating fern, yet. In order to assess the possible presence of arsenate reductase in P. vittata, two recombinant proteins, ACR2-His6 and Trx-His6-S-Pv2.5-8 were prepared in Escherichia coli, purified and used to produce polyclonal antibodies. The presence of these two enzymes was evaluated by qRT-PCR, immunoblotting and direct MS analysis. Enzymatic activity was detected in crude extracts. For the first time we detected and identified two arsenate reductase proteins (PvACR2 and Pv2.5-8) in sporophytes and gametophytes of P. vittata. Despite an increase of the mRNA levels for both proteins in roots, no difference was observed at the protein level after arsenic treatment. Overall, our data demonstrate the constitutive protein expression of PvACR2 and Pv2.5-8 in P. vittata tissues and propose their specific role in the complex metabolic network of arsenic reduction.

  9. The arsenic hyperaccumulating Pteris vittata expresses two arsenate reductases

    NASA Astrophysics Data System (ADS)

    Cesaro, Patrizia; Cattaneo, Chiara; Bona, Elisa; Berta, Graziella; Cavaletto, Maria

    2015-09-01

    Enzymatic reduction of arsenate to arsenite is the first known step in arsenate metabolism in all organisms. Although the presence of one mRNA arsenate reductase (PvACR2) has been characterized in gametophytes of P. vittata, no arsenate reductase protein has been directly observed in this arsenic hyperaccumulating fern, yet. In order to assess the possible presence of arsenate reductase in P. vittata, two recombinant proteins, ACR2-His6 and Trx-His6-S-Pv2.5-8 were prepared in Escherichia coli, purified and used to produce polyclonal antibodies. The presence of these two enzymes was evaluated by qRT-PCR, immunoblotting and direct MS analysis. Enzymatic activity was detected in crude extracts. For the first time we detected and identified two arsenate reductase proteins (PvACR2 and Pv2.5-8) in sporophytes and gametophytes of P. vittata. Despite an increase of the mRNA levels for both proteins in roots, no difference was observed at the protein level after arsenic treatment. Overall, our data demonstrate the constitutive protein expression of PvACR2 and Pv2.5-8 in P. vittata tissues and propose their specific role in the complex metabolic network of arsenic reduction.

  10. Feasibility of using hyperaccumulating plants to bioremediate metal-contaminated soil

    SciTech Connect

    Kelly, R.J.; Guerin, T.F.

    1995-12-31

    A feasibility study was carried out to determine whether selected plants were capable of hyperaccumulating anthropogenic sources of metals found in soils from three contaminated sites. A trial was conducted using the previously reported hyperaccumulators, Armeria maritima (thrift), Impatiens balsamina (balsam), Alyssum saxatile (gold dust), and the control species, Brassica oleracea (cabbage). Although none of these plants showed any substantial hyperaccumulation of Cu, Zn, Pb, and Cd, it was established that there is an optimum period in the life-cycle of these plants in which the metal concentration reaches a maximum. This period was dependent on the metal, soil, and plant type. The current paper describes the data obtained for Zn and Cu uptake by thrift.

  11. Metabolite fingerprinting of pennycress (Thlaspi arvense L.) embryos to assess active pathways during oil synthesis

    SciTech Connect

    Tsogtbaatar, Enkhtuul; Cocuron, Jean -Christophe; Sonera, Marcos Corchado; Alonso, Ana Paula

    2015-02-22

    Pennycress (Thlaspi arvense L.), a plant naturalized to North America, accumulates high levels of erucic acid in its seeds, which makes it a promising biodiesel and industrial crop. The main carbon sinks in pennycress embryos were found to be proteins, fatty acids, and cell wall, which respectively represented 38.5, 33.2, and 27.0% of the biomass at 21 days after pollination. Erucic acid reached a maximum of 36% of the total fatty acids. Together these results indicate that total oil and erucic acid contents could be increased to boost the economic competitiveness of this crop. Understanding the biochemical basis of oil synthesis in pennycress embryos is therefore timely and relevant to guide future breeding and/or metabolic engineering efforts. For this purpose, a combination of metabolomics approaches was conducted to assess the active biochemical pathways during oil synthesis. First, gas chromatography-mass spectrometry (GC-MS) profiling of intracellular metabolites highlighted three main families of compounds: organic acids, amino acids, and sugars/sugar alcohols. Secondly, these intermediates were quantified in developing pennycress embryos by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring mode. Finally, partitional clustering analysis grouped the intracellular metabolites that shared a similar pattern of accumulation over time into eight clusters. In conclusion, this study underlined that: (i) sucrose might be stored rather than cleaved into hexoses; (ii) glucose and glutamine would be the main sources of carbon and nitrogen, respectively; and (iii) glycolysis, the oxidative pentose phosphate pathway, the tricarboxylic acid cycle, and the Calvin cycle were active in developing pennycress embryos.

  12. Recovery of zinc from hyperaccumulator plants: Sedum plumbizincicola.

    PubMed

    Yang, Jian-Guang; Yang, Jian-Ying; Peng, Chang-Hong; Tang, Chao-Bo; Zhou, Ke-Cao

    2009-06-01

    Hyperaccumulator biomass harvested after heavy-metal phytoremediation must be considered as hazardous waste that should be contained or treated appropriately before disposal or reuse. As a potential method to detoxify the biomass and to convert this material to a suitable fertilizer or mulch, leaching of heavy metals from Sedum plumbizincicola biomass was studied by using ammonia-ammonium chloride solution as a leaching agent. The research was carried out in two phases: (i) a leaching study to determine the heavy metal:zinc extraction efficiency of this leaching agent and (ii) a thermodynamic analysis to identify the likely reactions and stable Zn(II) species formed in the leaching systems. Experimentally, a Taguchi orthogonal experiment with four variable parameter elements: leaching temperature, nNH4Cl:nNH3 ratio, leaching time and solid-liquid ratio, each at three levels, was used to optimize the experimental parameters by the analysis of variances. Application of the Taguchi technique significantly reduced the time and cost required for the experimental investigation. The findings indicate that leaching temperature had the most dominant effect on metal extraction performance, followed by nNH4Cl:nNH3 ratio, solid-liquid ratio and leaching time. Accordingly, the optimum leaching conditions were determined as temperature: 60 degrees C, nNH4Cl:nNH3 = 0.6, leaching time: 2 h and solid/liquid ratio: 5:1. The total zinc removal after leaching under the optimum conditions reached 97.95%. The thermodynamic study indicated that the dominant species produced by the leaching process should be the soluble species Zn(NH3)4(2+).

  13. The Metal Hyperaccumulator Alyssum murale Uses Nitrogen and Oxygen Donor Ligands for Ni Transport and Storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Kotodesh genotype of the nickel (Ni) hyperaccumulator Alyssum murale was examined to determine the compartmentalization and internal speciation of Ni, and other elements, in an effort to ascertain the mechanism used by this plant to tolerate extremely high shoot Ni concentrations. Plants were g...

  14. Transcriptomic Analysis of Cadmium Stress Response in the Heavy Metal Hyperaccumulator Sedum alfredii Hance

    PubMed Central

    Yang, Xiaoe; Liu, Jian-Xiang

    2013-01-01

    The Sedum alfredii Hance hyperaccumulating ecotype (HE) has the ability to hyperaccumulate cadmium (Cd), as well as zinc (Zn) and lead (Pb) in above-ground tissues. Although many physiological studies have been conducted with these plants, the molecular mechanisms underlying their hyper-tolerance to heavy metals are largely unknown. Here we report on the generation of 9.4 gigabases of adaptor-trimmed raw sequences and the assembly of 57,162 transcript contigs in S. alfredii Hance (HE) shoots by the combination of Roche 454 and Illumina/Solexa deep sequencing technologies. We also have functionally annotated the transcriptome and analyzed the transcriptome changes upon Cd hyperaccumulation in S. alfredii Hance (HE) shoots. There are 110 contigs and 123 contigs that were up-regulated (Fold Change ≧2.0) and down-regulated (Fold Change ≦0.5) by chronic Cd treatment in S. alfredii Hance (HE) at q-value cutoff of 0.005, respectively. Quantitative RT-PCR was employed to compare gene expression patterns between S. alfredii Hance (HE) and non-hyperaccumulating ecotype (NHE). Our results demonstrated that several genes involved in cell wall modification, metal translocation and remobilization were more induced or constitutively expressed at higher levels in HE shoots than that in NHE shoots in response to Cd exposure. Together, our study provides large-scale expressed sequence information and genome-wide transcriptome profiling of Cd responses in S. alfredii Hance (HE) shoots. PMID:23755133

  15. High-throughput fluorescence-activated cell sorting for lipid hyperaccumulating Chlamydomonas reinhardtii mutants.

    PubMed

    Xie, Bo; Stessman, Dan; Hart, Jason H; Dong, Haili; Wang, Yingjun; Wright, David A; Nikolau, Basil J; Spalding, Martin H; Halverson, Larry J

    2014-09-01

    The genetically tractable microalga Chlamydomonas reinhardtii has many advantages as a model for renewable bioproducts and/or biofuels production. However, one limitation of C. reinhardtii is its relatively low-lipid content compared with some other algal species. To overcome this limitation, we combined ethane methyl sulfonate mutagenesis with fluorescence-activated cell sorting (FACS) of cells stained with the lipophilic stain Nile Red to isolate lipid hyperaccumulating mutants of C. reinhardtii. By manipulating the FACS gates, we sorted mutagenized cells with extremely high Nile Red fluorescence signals that were rarely detected in nonmutagenized populations. This strategy successfully isolated several putative lipid hyperaccumulating mutants exhibiting 23% to 58% (dry weight basis) higher fatty acid contents than their progenitor strains. Significantly, for most mutants, nitrogen starvation was not required to attain high-lipid content nor was there a requirement for a deficiency in starch accumulation. Microscopy of Nile Red stained cells revealed that some mutants exhibit an increase in the number of lipid bodies, which correlated with TLC analysis of triacyglycerol content. Increased lipid content could also arise through increased biomass production. Collectively, our findings highlight the ability to enhance intracellular lipid accumulation in algae using random mutagenesis in conjunction with a robust FACS and lipid yield verification regime. Our lipid hyperaccumulating mutants could serve as a genetic resource for stacking additional desirable traits to further increase lipid production and for identifying genes contributing to lipid hyperaccumulation, without lengthy lipid-induction periods.

  16. Uncoupling of reactive oxygen species accumulation and defence signalling in the metal hyperaccumulator plant Noccaea caerulescens.

    PubMed

    Fones, Helen N; Eyles, Chris J; Bennett, Mark H; Smith, J Andrew C; Preston, Gail M

    2013-09-01

    The metal hyperaccumulator plant Noccaea caerulescens is protected from disease by the accumulation of high concentrations of metals in its aerial tissues, which are toxic to many pathogens. As these metals can lead to the production of damaging reactive oxygen species (ROS), metal hyperaccumulator plants have developed highly effective ROS tolerance mechanisms, which might quench ROS-based signals. We therefore investigated whether metal accumulation alters defence signalling via ROS in this plant. We studied the effect of zinc (Zn) accumulation by N. caerulescens on pathogen-induced ROS production, salicylic acid accumulation and downstream defence responses, such as callose deposition and pathogenesis-related (PR) gene expression, to the bacterial pathogen Pseudomonas syringae pv. maculicola. The accumulation of Zn caused increased superoxide production in N. caerulescens, but inoculation with P. syringae did not elicit the defensive oxidative burst typical of most plants. Defences dependent on signalling through ROS (callose and PR gene expression) were also modified or absent in N. caerulescens, whereas salicylic acid production in response to infection was retained. These observations suggest that metal hyperaccumulation is incompatible with defence signalling through ROS and that, as metal hyperaccumulation became effective as a form of elemental defence, normal defence responses became progressively uncoupled from ROS signalling in N. caerulescens.

  17. Organic acids rather than histidine predominate in Ni chelation in Alyssum hyperaccumulator xylem exudate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A better understanding of Ni uptake mechanisms by hyperaccumulator plants is necessary to improve Ni uptake efficiency for phytoremediation technologies i.e. phytomining. It is known that an important aspect of Ni translocation involves Ni chelation with organic ligands. However, it is still not cle...

  18. Elevated Nicotianamine Levels in Arabidopsis halleri Roots Play a Key Role in Zinc Hyperaccumulation[W

    PubMed Central

    Deinlein, Ulrich; Weber, Michael; Schmidt, Holger; Rensch, Stefan; Trampczynska, Aleksandra; Hansen, Thomas H.; Husted, Søren; Schjoerring, Jan K.; Talke, Ina N.; Krämer, Ute; Clemens, Stephan

    2012-01-01

    Zn deficiency is among the leading health risk factors in developing countries. Breeding of Zn-enriched crops is expected to be facilitated by molecular dissection of plant Zn hyperaccumulation (i.e., the ability of certain plants to accumulate Zn to levels >100-fold higher than normal plants). The model hyperaccumulators Arabidopsis halleri and Noccaea caerulescens share elevated nicotianamine synthase (NAS) expression relative to nonaccumulators among a core of alterations in metal homeostasis. Suppression of Ah-NAS2 by RNA interference (RNAi) resulted in strongly reduced root nicotianamine (NA) accumulation and a concomitant decrease in root-to-shoot translocation of Zn. Speciation analysis by size-exclusion chromatography coupled to inductively coupled plasma mass spectrometry showed that the dominating Zn ligands in roots were NA and thiols. In NAS2-RNAi plants, a marked increase in Zn-thiol species was observed. Wild-type A. halleri plants cultivated on their native soil showed elemental profiles very similar to those found in field samples. Leaf Zn concentrations in NAS2-RNAi lines, however, did not reach the Zn hyperaccumulation threshold. Leaf Cd accumulation was also significantly reduced. These results demonstrate a role for NAS2 in Zn hyperaccumulation also under near-natural conditions. We propose that NA forms complexes with Zn(II) in root cells and facilitates symplastic passage of Zn(II) toward the xylem. PMID:22374395

  19. The metal hyperaccumulators from New Caledonia can broaden our understanding of nickel accumulation in plants

    PubMed Central

    Jaffré, Tanguy; Pillon, Yohan; Thomine, Sébastien; Merlot, Sylvain

    2013-01-01

    While an excess of metals such as zinc, cadmium or nickel (Ni) is toxic for most plants, about 500 plant species called hyperaccumulators are able to accumulate high amounts of these metals. These plants and the underlying mechanisms are receiving an increasing interest because of their potential use in sustainable biotechnologies such as biofortification, phytoremediation, and phytomining. Among hyperaccumulators, about 400 species scattered in 40 families accumulate Ni. Despite this wide diversity, our current knowledge of the mechanisms involved in Ni accumulation is still limited and mostly restricted to temperate herbaceous Brassicaceae. New Caledonia is an archipelago of the tropical southwest pacific with a third of its surface (5500 km2) covered by Ni-rich soils originating from ultramafic rocks. The rich New Caledonia flora contains 2145 species adapted to these soils, among which 65 are Ni hyperaccumulators, including lianas, shrubs or trees, mostly belonging to the orders Celastrales, Oxalidales, Malpighiales, and Gentianales. We present here our current knowledge on Ni hyperaccumulators from New Caledonia and the latest molecular studies developed to better understand the mechanisms of Ni accumulation in these plants. PMID:23898341

  20. Rinorea niccolifera (Violaceae), a new, nickel-hyperaccumulating species from Luzon Island, Philippines.

    PubMed

    Fernando, Edwino S; Quimado, Marilyn O; Doronila, Augustine I

    2014-01-01

    A new, nickel-hyperaccumulating species of Rinorea (Violaceae), Rinorea niccolifera Fernando, from Luzon Island, Philippines, is described and illustrated. This species is most similar to the widespread Rinorea bengalensis by its fasciculate inflorescences and smooth subglobose fruits with 3 seeds, but it differs by its glabrous ovary with shorter style (5 mm long), the summit of the staminal tube sinuate to entire and the outer surface smooth, generally smaller leaves (3-8 cm long × 2-3 cm wide), and smaller fruits (0.6-0.8 cm diameter). Rinorea niccolifera accumulates to >18,000 µg g(-1) of nickel in its leaf tissues and is thus regarded as a Ni hyperaccumulator.

  1. Localization of nickel in tissues of Streptanthus polygaloides Gray (Cruciferae) and endemic nickel hyperaccumulators from California.

    PubMed

    Sánchez-Mata, Daniel; de la Fuente, Vicenta; Rufo, Lourdes; Rodríguez, Nuria; Amils, Ricardo

    2014-01-01

    The genus Streptanthus Nutt. is one of the most important indicators of ultramafic floras in western North America. This genus contains taxa that are endemic or tolerant of ultramafic soils. Streptanthus polygaloides is an annual nickel hyperaccumulator strictly confined to ultramafic soils throughout the Californian Sierra Nevada foothills. Nickel concentration in S. polygaloides populations was evaluated by elemental microanalysis using inductively coupled plasma mass spectrometry (ICP-MS). Representative samples of S. polygaloides roots, stems, leaves, flowers, and fruits were studied by scanning electron microscopy (SEM) coupled to an energy-dispersive X-ray probe (SEM-EDX). Results show Ni accumulation values between 0.09 and 1.18 %, and a distribution pattern similar to that observed in other Ni hyperaccumulator taxa, with the leaf epidermis accumulating the largest concentrations.

  2. A more complete picture of metal hyperaccumulation through next-generation sequencing technologies

    PubMed Central

    Verbruggen, Nathalie; Hanikenne, Marc; Clemens, Stephan

    2013-01-01

    The mechanistic understanding of metal hyperaccumulation has benefitted immensely from the use of molecular genetics tools developed for Arabidopsis thaliana. The revolution in DNA sequencing will enable even greater strides in the near future, this time not restricted to the family Brassicaceae. Reference genomes are within reach for many ecologically interesting species including heterozygous outbreeders. They will allow deep RNA-seq transcriptome studies and the re-sequencing of contrasting individuals to unravel the genetic basis of phenotypic variation. Cell-type specific transcriptome analyses, which will be essential for the dissection of metal translocation pathways in hyperaccumulators, can be achieved through the combination of RNA-seq and translatome approaches. Affordable high-resolution genotyping of many individuals enables the elucidation of quantitative trait loci in intra- and interspecific crosses as well as through genome-wide association mapping across large panels of accessions. Furthermore, genome-wide scans have the power to detect loci under recent selection. Together these approaches will lead to a detailed understanding of the evolutionary path towards the emergence of hyperaccumulation traits. PMID:24098304

  3. Application of rhizosphere interaction of hyperaccumulator Noccaea caerulescens to remediate cadmium-contaminated agricultural soil.

    PubMed

    Yang, Yong; Jiang, Rong-Feng; Wang, Wei; Li, Hua-Fen

    2011-10-01

    There is an urgent requirement for selecting appropriate technologies to solve food safety problems due to soil contamination. In this study, the hyperaccumulator Noccaea caerulescens and a high Cd accumulator pakchoi cultivar (Brassica rapa L. spp. Chinenesis cv.) were grown in a moderately Cd-contaminated soil with three planting systems (monocrop, inter-crop, and crop-rotation) and three growing durations (25, 50, and 75 days) to study the role of rhizosphere interaction of both species on the uptake of Cd. The Cd accumulations in the shoot of pakchoi were significantly reduced in the inter-crop treatment, also the decreased percentage increased with rhizosphere interaction between the two species. In the inter-crop systems of 75 days, the Cd concentration and amount in the shoot of pakchoi represented 54% and 83% reduction, respectively, while the total depletion of Cd decreased by approximate 19%. Although the Cd concentration and amount in the shoot of pakchoi were significantly reduced by 52% and 44%, respectively, in the crop-rotation treatment, the decreased percentage were markedly lower than in the inter-crop treatment. Therefore, the rhizosphere interaction of hyperaccumulator with non-hyperaccumulator may reduce the risk of vegetable contamination during making full use of or remediating the contaminated soil.

  4. Manganese uptake and accumulation by the hyperaccumulator plant Phytolacca acinosa Roxb. (Phytolaccaceae).

    PubMed

    Xue, S G; Chen, Y X; Reeves, Roger D; Baker, Alan J M; Lin, Q; Fernando, Denise R

    2004-10-01

    The perennial herb Phytolacca acinosa Roxb. (Phytolaccaceae), which occurs in Southern China, has been found to be a new manganese hyperaccumulator by means of field surveys on Mn-rich soils and by glasshouse experiments. This species not only has remarkable tolerance to Mn but also has extraordinary uptake and accumulation capacity for this element. The maximum Mn concentration in the leaf dry matter was 19,300 microg/g on Xiangtan Mn tailings wastelands, with a mean of 14,480 microg/g. Under nutrient solution culture conditions, P. acinosa could grow normally with Mn supplied at a concentration of 8000 micromol/l, although with less biomass than in control samples supplied with Mn at 5 micromol/l. Manganese concentration in the shoots increased with increasing external Mn levels, but the total mass of Mn accumulated in the shoots first increased and then decreased. At an Mn concentration of 5000 micromol/l in the culture solution, the Mn accumulation in the shoot dry matter was highest (258 mg/plant). However, the Mn concentration in the leaves reached its highest value (36,380 microg/g) at an Mn supply level of 12,000 micromol/l. These results confirm that P. acinosa is an Mn hyperaccumulator which grows rapidly, has substantial biomass, wide distribution and a broad ecological amplitude. This species provides a new plant resource for exploring the mechanism of Mn hyperaccumulation, and has potential for use in the phytoremediation of Mn-contaminated soils.

  5. [Characteristics of 23 species of weed in northeast of China hyperaccumulating PAHs in contaminated soils].

    PubMed

    Zhang, Min; Liang, Hong; Gao, Da-Wen; Zhang, Bai-Hui; Li, Xin-Ping; Guo, Xiao-Hu

    2011-10-01

    Pot experiments were conducted to investigate the 23 species of weed accumulation characteristics of phenanthrene, as a representative of polycyclic aromatic hydrocarbons (PAHs), from soil in the northeast of China. The result indicated that among the 23 species, the bioconcentration factors of Taraxacum ohwianum K., Potentilla aiscolor B. and Chelidonium majus L. were all higher than 1, which were 1.01, 4.98, 38.24 respectively. The phenanthrene concentrations in roots were 2.83, 16.34 and 9.66 mg/kg which were lower than those in aboveground part with phenanthrene concentrations were 15.18, 74.70 and 573.62 mg/kg, respectively. The hyperaccumulators were indicated by strong conveyance of phenanthrene from root to aboveground part. The analysis of phenanthrene concentration in aboveground weed and aboveground plant biomass showed that the accumulation of phenanthrene in plant were not correlated with their biomass. It concluded that Taraxacum ohwianum K., Potentilla aiscolor B. and Chelidonium majus L. had hyperaccumulative characteristics of phenanthrene, and it is possible to screen out plants with high biomass and hyperaccumulation capability.

  6. Thermal Characteristics of Hyperaccumulator and Fate of Heavy Metals during Thermal Treatment of Sedum plumbizincicola.

    PubMed

    Zhong, Daoxu; Zhong, Zhaoping; Wu, Longhua; Xue, Hui; Song, Zuwei; Luo, Yongming

    2015-01-01

    Thermal treatment is one of the most promising disposal techniques for heavy metal- (HM)-enriched hyperaccumulators. However, the thermal characteristics and fate of HMs during thermal treatment of hyperaccumulator biomass need to be known in detail. A horizontal tube furnace was used to analyze the disposal process of hyperaccumulator biomass derived from a phyto-extracted field in which the soil was moderately contaminated with heavy metals. Different operational conditions regarding temperature and gas composition were tested. A thermo-dynamic analysis by advanced system for process engineering was performed to predict HM speciation during thermal disposal and SEM-EDS, XRD and sequential chemical extraction were used to characterize the heavy metals. The recovery of Zn, Pb and Cd in bottom ash decreased with increasing temperature but recovery increased in the fly ash. Recovery of Zn, Pb and Cd fluctuated with increasing air flow rate and the metal recovery rates were higher in the fly ash than the bottom ash. Most Cl, S, Fe, Al and SiO2 were found as alkali oxides, SO2, Fe2(SO4)3, iron oxide, Ca3Al2O6, K2SiO3 and SiO2 instead of reacting with HMs. Thus, the HMs were found to occur as the pure metals and their oxides during the combustion process and as the sulfides during the reducing process.

  7. Hyperaccumulator Alyssum murale Relies on a Different Metal Storage Mechanism for Cobalt than for Nickel

    SciTech Connect

    Tappero, R.; Peltier, E; Grafe, M; Heidel, K; Ginder-Vogel, M; Livi, K; Rivers, M; Marcus, M; Chaney, R; Sparks, D

    2007-01-01

    The nickel (Ni) hyperaccumulator Alyssum murale has been developed as a commercial crop for phytoremediation/phytomining Ni from metal-enriched soils. Here, metal co-tolerance, accumulation and localization were investigated for A. murale exposed to metal co-contaminants. A. murale was irrigated with Ni-enriched nutrient solutions containing basal or elevated concentrations of cobalt (Co) or zinc (Zn). Metal localization and elemental associations were investigated in situ with synchrotron X-ray microfluorescence (SXRF) and computed-microtomography (CMT). A. murale hyperaccumulated Ni and Co (> 1000 {micro}g g{sup -1} dry weight) from mixed-metal systems. Zinc was not hyperaccumulated. Elevated Co or Zn concentrations did not alter Ni accumulation or localization. SXRF images showed uniform Ni distribution in leaves and preferential localization of Co near leaf tips/margins. CMT images revealed that leaf epidermal tissue was enriched with Ni but devoid of Co, that Co was localized in the apoplasm of leaf ground tissue and that Co was sequestered on leaf surfaces near the tips/margins. Cobalt-rich mineral precipitate(s) form on leaves of Co-treated A. murale. Specialized biochemical processes linked with Ni (hyper)tolerance in A. murale do not confer (hyper)tolerance to Co. A. murale relies on a different metal storage mechanism for Co (exocellular sequestration) than for Ni (vacuolar sequestration).

  8. Relationship between metal and pigment concentrations in the Fe-hyperaccumulator moss Scopelophila ligulata.

    PubMed

    Nakajima, Hiromitsu; Itoh, Kiminori

    2017-01-01

    Scopelophila ligulata is known to be a Fe-hyperaccumulator moss; however, its mechanism of accumulation and the effects of Fe on pigments remain unclear. To clarify the effects, we measured its metal and pigment concentrations. The Fe concentration in S. ligulata was 10-61 times higher than that in normal mosses, confirming that the moss is a Fe-hyperaccumulator. The black samples of S. ligulata had the highest Fe concentration (2.9 wt%) and the second in the order of decreasing Fe concentration (2.2 wt%), which explains their color and indicates that the excess amount of Fe is distributed through the plant body. Moreover, we observed that the concentration of Ca is negatively correlated with the concentrations of pigments and, conversely, that the concentration of K is positively correlated with the concentrations of pigments. This inverse relationship between Ca and K can be explained by the reduced uptake of K in S. ligulata in response to Ca stress, which is supported by the fact that the concentration of Ca is negatively correlated with that of K. These findings provide a better understanding of the relationships between metals and pigments in the Fe-hyperaccumulator moss S. ligulata.

  9. De novo transcriptome assemblies of four accessions of the metal hyperaccumulator plant Noccaea caerulescens

    PubMed Central

    Blande, Daniel; Halimaa, Pauliina; Tervahauta, Arja I; Aarts, Mark G.M.; Kärenlampi, Sirpa O

    2017-01-01

    Noccaea caerulescens of the Brassicaceae family has become the key model plant among the metal hyperaccumulator plants. Populations/accessions of N. caerulescens from geographic locations with different soil metal concentrations differ in their ability to hyperaccumulate and hypertolerate metals. Comparison of transcriptomes in several accessions provides candidates for detailed exploration of the mechanisms of metal accumulation and tolerance and local adaptation. This can have implications in the development of plants for phytoremediation and improved mineral nutrition. Transcriptomes from root and shoot tissues of four N. caerulescens accessions with contrasting Zn, Cd and Ni hyperaccumulation and tolerance traits were sequenced with Illumina Hiseq2000. Transcriptomes were assembled using the Trinity de novo assembler and were annotated and the protein sequences predicted. The comparison against the BUSCO plant early release dataset indicated high-quality assemblies. The predicted protein sequences have been clustered into ortholog groups with closely related species. The data serve as important reference sequences in whole transcriptome studies, in analyses of genetic differences between the accessions and other species, and for primer design. PMID:28140388

  10. Effects of arsenic on concentration and distribution of nutrients in the fronds of the arsenic hyperaccumulator Pteris vittata L.

    PubMed

    Tu, Cong; Ma, Lena Q

    2005-05-01

    Pteris vittata was the first terrestrial plant known to hyperaccumulate arsenic (As). However, it is unclear how As hyperaccumulation influences nutrient uptake by this plant. P. vittata fern was grown in soil spiked with 0-500 mg As kg(-1) in the greenhouse for 24 weeks. The concentrations of essential macro- (P, K, Ca, and Mg) and micro- (Fe, Mn, Cu, Zn, B and Mo) elements in the fronds of different age were examined. Both macro- and micronutrients in the fronds were found to be within the normal concentration ranges for non-hyperaccumulators. However, As hyperaccumulation did influence the elemental distribution among fronds of different age of P. vittata. Arsenic-induced P and K enhancements in the fronds contributed to the As-induced growth stimulation at low As levels. The frond P/As molar ratios of 1.0 can be used as the threshold value for normal growth of P. vittata. Potassium may function as a counter-cation for As in the fronds as shown by the As-induced K increases in the fronds. The present findings not only demonstrate that P. vittata has the ability to maintain adequate concentrations of essential nutrients while hyperaccumulating As from the soil, but also have implications for soil management (fertilization in particular) of P. vittata in As phytoextraction practice.

  11. Root and shoot transcriptome analysis of two ecotypes of Noccaea caerulescens uncovers the role of NcNramp1 in Cd hyperaccumulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Zn/Cd hyperaccumulator, Noccaea caerulescens, has been studied extensively for its ability to accumulate Zn and Cd in its leaves to extremely high levels. Previous studies have indicated that the Zn and Cd hyperaccumulation trait exhibited by this species involves different transport and toleran...

  12. Growth and metal accumulation of an Alyssum murale nickel hyperaccumulator ecotype co-cropped with Alyssum montanum or perennial ryegrass in serpentine soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than 400 plant species naturally accumulate high levels of metals such as Cd, Cu, Co, Mn, Ni, and Zn. The genus Alyssum (Brassicaceae) contains the greatest number of reported Ni hyperaccumulators (50), many of which can achieve 3 wt% Ni in dry leaves. Some Alyssum hyperaccumulators are viabl...

  13. The potential of phytoremediation using hyperaccumulator plants: a case study at a lead-zinc mine site.

    PubMed

    Lorestani, Bahareh; Cheraghi, Mehrdad; Yousefi, Nafiseh

    2012-09-01

    Contamination with heavy metals is one of the most pressing threats to water and soil resources, as well as human health. Phytoremediation might potentially be used to remediate metal-contaminated sites. A major advance in the development of phytoremediation for heavy metal affected soils was the discovery of heavy metal hyperaccumulation in plants. This study applied several established criteria to identify hyperaccumulator plants. A case study was conducted at a mining area in the Hamedan province in the west central region of Iran. The results indicated that plant metal accumulation differed among species and plant parts. Plant species grown in substrata with elevated metal levels contained significantly higher metal levels. Using the most common criteria, Euphorbia macroclada and Centaurea virgata can be classified as hyperaccumulators of specific heavy metals measured in this study and they might potentially be used for the phytoremediation of contaminated soils.

  14. Synergistic effects of arbuscular mycorrhizal fungi and phosphate rock on heavy metal uptake and accumulation by an arsenic hyperaccumulator.

    PubMed

    Leung, H M; Wu, F Y; Cheung, K C; Ye, Z H; Wong, M H

    2010-09-15

    The effects of arbuscular mycorrhizal (AM) fungi and phosphate rock on the phytorextraction efficiency of a hyperaccumulator (Pteris vittata) and a non-hyperaccumulator (Cynodon dactylon) plant were studied. Both seedlings were planted in As contaminated soil under different treatments [(1) control (contaminated soil only), (2) indigenous mycorrhizas (IM), (3) mixed AM inoculum [indigenous mycorrhiza + Glomus mosseae (IM/Gm)] and (4) IM/Gm + phosphate rock (P rock)] with varying intensities (40%, 70% and 100%) of water moisture content (WMC). Significant As reduction in soil (23.8% of soil As reduction), increase in plant biomass (17.8 g/pot) and As accumulation (2054 mg/kg DW) were observed for P. vittata treated with IM/Gm + PR at 100% WMC level. The overall results indicated that the synergistic effect of mycorrhiza and P rock affected As subcellular distribution of the hyperaccumulator and thereby altered its As removal efficiency under well-watered conditions.

  15. Selenium hyperaccumulators harbor a diverse endophytic bacterial community characterized by high selenium resistance and plant growth promoting properties

    PubMed Central

    Sura-de Jong, Martina; Reynolds, Ray J. B.; Richterova, Klara; Musilova, Lucie; Staicu, Lucian C.; Chocholata, Iva; Cappa, Jennifer J.; Taghavi, Safiyh; van der Lelie, Daniel; Frantik, Tomas; Dolinova, Iva; Strejcek, Michal; Cochran, Alyssa T.; Lovecka, Petra; Pilon-Smits, Elizabeth A. H.

    2015-01-01

    Selenium (Se)-rich plants may be used to provide dietary Se to humans and livestock, and also to clean up Se-polluted soils or waters. This study focused on endophytic bacteria of plants that hyperaccumulate selenium (Se) to 0.5–1% of dry weight. Terminal restriction fragment length polymorphism (T-RFLP) analysis was used to compare the diversity of endophytic bacteria of hyperaccumulators Stanleya pinnata (Brassicaceae) and Astragalus bisulcatus (Fabaceae) with those from related non-accumulators Physaria bellii (Brassicaceae) and Medicago sativa (Fabaceae) collected on the same, seleniferous site. Hyperaccumulators and non-accumulators showed equal T-RF diversity. Parsimony analysis showed that T-RFs from individuals of the same species were more similar to each other than to those from other species, regardless of plant Se content or spatial proximity. Cultivable endophytes from hyperaccumulators S. pinnata and A. bisulcatus were further identified and characterized. The 66 bacterial morphotypes were shown by MS MALDI-TOF Biotyper analysis and 16S rRNA gene sequencing to include strains of Bacillus, Pseudomonas, Pantoea, Staphylococcus, Paenibacillus, Advenella, Arthrobacter, and Variovorax. Most isolates were highly resistant to selenate and selenite (up to 200 mM) and all could reduce selenite to red elemental Se, reduce nitrite and produce siderophores. Seven isolates were selected for plant inoculation and found to have plant growth promoting properties, both in pure culture and when co-cultivated with crop species Brassica juncea (Brassicaceae) or M. sativa. There were no effects on plant Se accumulation. We conclude that Se hyperaccumulators harbor an endophytic bacterial community in their natural seleniferous habitat that is equally diverse to that of comparable non-accumulators. The hyperaccumulator endophytes are characterized by high Se resistance, capacity to produce elemental Se and plant growth promoting properties. PMID:25784919

  16. Molecular Mechanisms of Selenium Tolerance and Hyperaccumulation in Stanleya pinnata1[W][OA

    PubMed Central

    Freeman, John L.; Tamaoki, Masanori; Stushnoff, Cecil; Quinn, Colin F.; Cappa, Jennifer J.; Devonshire, Jean; Fakra, Sirine C.; Marcus, Matthew A.; McGrath, Steve P.; Van Hoewyk, Doug; Pilon-Smits, Elizabeth A.H.

    2010-01-01

    The molecular mechanisms responsible for selenium (Se) tolerance and hyperaccumulation were studied in the Se hyperaccumulator Stanleya pinnata (Brassicaceae) by comparing it with the related secondary Se accumulator Stanleya albescens using a combination of physiological, structural, genomic, and biochemical approaches. S. pinnata accumulated 3.6-fold more Se and was tolerant to 20 μm selenate, while S. albescens suffered reduced growth, chlorosis and necrosis, impaired photosynthesis, and high levels of reactive oxygen species. Levels of ascorbic acid, glutathione, total sulfur, and nonprotein thiols were higher in S. pinnata, suggesting that Se tolerance may in part be due to increased antioxidants and up-regulated sulfur assimilation. S. pinnata had higher selenocysteine methyltransferase protein levels and, judged from liquid chromatography-mass spectrometry, mainly accumulated the free amino acid methylselenocysteine, while S. albescens accumulated mainly the free amino acid selenocystathionine. S. albescens leaf x-ray absorption near-edge structure scans mainly detected a carbon-Se-carbon compound (presumably selenocystathionine) in addition to some selenocysteine and selenate. Thus, S. albescens may accumulate more toxic forms of Se in its leaves than S. pinnata. The species also showed different leaf Se sequestration patterns: while S. albescens showed a diffuse pattern, S. pinnata sequestered Se in localized epidermal cell clusters along leaf margins and tips, concentrated inside of epidermal cells. Transcript analyses of S. pinnata showed a constitutively higher expression of genes involved in sulfur assimilation, antioxidant activities, defense, and response to (methyl)jasmonic acid, salicylic acid, or ethylene. The levels of some of these hormones were constitutively elevated in S. pinnata compared with S. albescens, and leaf Se accumulation was slightly enhanced in both species when these hormones were supplied. Thus, defense-related phytohormones

  17. Conserved but Attenuated Parental Gene Expression in Allopolyploids: Constitutive Zinc Hyperaccumulation in the Allotetraploid Arabidopsis kamchatica

    PubMed Central

    Paape, Timothy; Hatakeyama, Masaomi; Shimizu-Inatsugi, Rie; Cereghetti, Teo; Onda, Yoshihiko; Kenta, Tanaka; Sese, Jun; Shimizu, Kentaro K.

    2016-01-01

    Allopolyploidization combines parental genomes and often confers broader species distribution. However, little is known about parentally transmitted gene expression underlying quantitative traits following allopolyploidization because of the complexity of polyploid genomes. The allopolyploid species Arabidopsis kamchatica is a natural hybrid of the zinc hyperaccumulator Arabidopsis halleri and of the nonaccumulator Arabidopsis lyrata. We found that A. kamchatica retained the ability to hyperaccumulate zinc from A. halleri and grows in soils with both low and high metal content. Hyperaccumulation of zinc by A. kamchatica was reduced to about half of A. halleri, but is 10-fold greater than A. lyrata. Homeologs derived from A. halleri had significantly higher levels of expression of genes such as HEAVY METAL ATPASE4 (HMA4), METAL TRANSPORTER PROTEIN1 and other metal ion transporters than those derived from A. lyrata, which suggests cis-regulatory differences. A. kamchatica has on average about half the expression of these genes compared with A. halleri due to fixed heterozygosity inherent in allopolyploids. Zinc treatment significantly changed the ratios of expression of 1% of homeologous pairs, including genes putatively involved in metal homeostasis. Resequencing data showed a significant reduction in genetic diversity over a large genomic region (290 kb) surrounding the HMA4 locus derived from the A. halleri parent compared with the syntenic A. lyrata-derived region, which suggests different evolutionary histories. We also estimated that three A. halleri-derived HMA4 copies are present in A. kamchatica. Our findings support a transcriptomic model in which environment-related transcriptional patterns of both parents are conserved but attenuated in the allopolyploids. PMID:27413047

  18. Conserved but Attenuated Parental Gene Expression in Allopolyploids: Constitutive Zinc Hyperaccumulation in the Allotetraploid Arabidopsis kamchatica.

    PubMed

    Paape, Timothy; Hatakeyama, Masaomi; Shimizu-Inatsugi, Rie; Cereghetti, Teo; Onda, Yoshihiko; Kenta, Tanaka; Sese, Jun; Shimizu, Kentaro K

    2016-11-01

    Allopolyploidization combines parental genomes and often confers broader species distribution. However, little is known about parentally transmitted gene expression underlying quantitative traits following allopolyploidization because of the complexity of polyploid genomes. The allopolyploid species Arabidopsis kamchatica is a natural hybrid of the zinc hyperaccumulator Arabidopsis halleri and of the nonaccumulator Arabidopsis lyrata We found that A. kamchatica retained the ability to hyperaccumulate zinc from A. halleri and grows in soils with both low and high metal content. Hyperaccumulation of zinc by A. kamchatica was reduced to about half of A. halleri, but is 10-fold greater than A. lyrata Homeologs derived from A. halleri had significantly higher levels of expression of genes such as HEAVY METAL ATPASE4 (HMA4), METAL TRANSPORTER PROTEIN1 and other metal ion transporters than those derived from A. lyrata, which suggests cis-regulatory differences. A. kamchatica has on average about half the expression of these genes compared with A. halleri due to fixed heterozygosity inherent in allopolyploids. Zinc treatment significantly changed the ratios of expression of 1% of homeologous pairs, including genes putatively involved in metal homeostasis. Resequencing data showed a significant reduction in genetic diversity over a large genomic region (290 kb) surrounding the HMA4 locus derived from the A. halleri parent compared with the syntenic A. lyrata-derived region, which suggests different evolutionary histories. We also estimated that three A. halleri-derived HMA4 copies are present in A. kamchatica Our findings support a transcriptomic model in which environment-related transcriptional patterns of both parents are conserved but attenuated in the allopolyploids.

  19. Mobilization of cadmium by dissolved organic matter in the rhizosphere of hyperaccumulator Sedum alfredii.

    PubMed

    Li, Tingqiang; Liang, Chengfeng; Han, Xuan; Yang, Xiaoe

    2013-05-01

    Pot experiments were conducted to investigate the role of dissolved organic matter (DOM) in the Cd speciation in the rhizosphere of hyperaccumulating ecotype (HE) and non-hyperaccumulating ecotype (NHE) of Sedum alfredii and its effects on Cd mobility. After growing HE S. alfredii, the rhizosphere soil solution pH of heavily polluted soil (HPS) and slightly polluted soil (SPS) was reduced by 0.49 and 0.40 units, respectively, due to enhanced DOC derived from root exudation. The total Cd concentration in soil solution decreased significantly but the decrease accounted for less than 1% of the total Cd uptake in the shoots of HE S. alfredii. Visual MINTEQ speciation predicted that Cd-DOM complexes were the dominant Cd species in soil solutions after the growth of S. alfredii for both soils, followed by the free metal Cd(2+) species. However, Cd-DOM complexes fraction in the rhizosphere soil solution of HE S. alfredii (89.1% and 74.6% for HPS and SPS, respectively) were much greater than NHE S. alfredii (82.8% and 64.7% for HPS and SPS, respectively). Resin equilibration experiment results indicated that DOM from the rhizosphere (R-DOM) of both ecotypes of S. alfredii had the ability to form complexes with Cd, whereas the degree of complexation was significantly higher for HE-R-DOM (79-89%) than NHE-R-DOM (63-74%) in the undiluted sample. The addition of HE-R-DOM significantly (P<0.05) increased the solubility of four Cd minerals while NHE-R-DOM was not as effective at the same concentration. It was concluded that DOM in the rhizosphere of hyperaccumulating ecotype of S. alfredii could significantly increase Cd mobility through the formation of soluble DOM-metal complexes.

  20. De novo assembly of the pennycress (Thlaspi arvense) transcriptome provides tools for the development of a winter cover crop and biodiesel feedstock.

    PubMed

    Dorn, Kevin M; Fankhauser, Johnathon D; Wyse, Donald L; Marks, M David

    2013-09-01

    Field pennycress (Thlaspi arvense L.) has potential as an oilseed crop that may be grown during fall (autumn) and winter months in the Midwestern United States and harvested in the early spring as a biodiesel feedstock. There has been little agronomic improvement in pennycress through traditional breeding. Recent advances in genomic technologies allow for the development of genomic tools to enable rapid improvements to be made through genomic assisted breeding. Here we report an annotated transcriptome assembly for pennycress. RNA was isolated from representative plant tissues, and 203 million unique Illumina RNA-seq reads were produced and used in the transcriptome assembly. The draft transcriptome assembly consists of 33 873 contigs with a mean length of 1242 bp. A global comparison of homology between the pennycress and Arabidopsis transcriptomes, along with four other Brassicaceae species, revealed a high level of global sequence conservation within the family. The final assembly was functionally annotated, allowing for the identification of putative genes controlling important agronomic traits such as flowering and glucosinolate metabolism. Identification of these genes leads to testable hypotheses concerning their conserved function and to rational strategies to improve agronomic properties in pennycress. Future work to characterize isoform variation between diverse pennycress lines and develop a draft genome sequence for pennycress will further direct trait improvement.

  1. De novo assembly of the pennycress (Thlaspi arvense) transcriptome provides tools for the development of a winter cover crop and biodiesel feedstock

    PubMed Central

    Dorn, Kevin M; Fankhauser, Johnathon D; Wyse, Donald L; Marks, M David

    2013-01-01

    Field pennycress (Thlaspi arvense L.) has potential as an oilseed crop that may be grown during fall (autumn) and winter months in the Midwestern United States and harvested in the early spring as a biodiesel feedstock. There has been little agronomic improvement in pennycress through traditional breeding. Recent advances in genomic technologies allow for the development of genomic tools to enable rapid improvements to be made through genomic assisted breeding. Here we report an annotated transcriptome assembly for pennycress. RNA was isolated from representative plant tissues, and 203 million unique Illumina RNA-seq reads were produced and used in the transcriptome assembly. The draft transcriptome assembly consists of 33 873 contigs with a mean length of 1242 bp. A global comparison of homology between the pennycress and Arabidopsis transcriptomes, along with four other Brassicaceae species, revealed a high level of global sequence conservation within the family. The final assembly was functionally annotated, allowing for the identification of putative genes controlling important agronomic traits such as flowering and glucosinolate metabolism. Identification of these genes leads to testable hypotheses concerning their conserved function and to rational strategies to improve agronomic properties in pennycress. Future work to characterize isoform variation between diverse pennycress lines and develop a draft genome sequence for pennycress will further direct trait improvement. PMID:23786378

  2. Fractionation of Stable Cadmium Isotopes in the Cadmium Tolerant Ricinus communis and Hyperaccumulator Solanum nigrum

    NASA Astrophysics Data System (ADS)

    Wei, Rongfei; Guo, Qingjun; Wen, Hanjie; Liu, Congqiang; Yang, Junxing; Peters, Marc; Hu, Jian; Zhu, Guangxu; Zhang, Hanzhi; Tian, Liyan; Han, Xiaokun; Ma, Jie; Zhu, Chuanwei; Wan, Yingxin

    2016-04-01

    Cadmium (Cd) isotopes provide new insights into Cd uptake, transport and storage mechanisms in plants. Therefore, the present study adopted the Cd-tolerant Ricinus communis and Cd-hyperaccumulator Solanum nigrum, which were cultured under controlled conditions in a nutrient solution with variable Cd supply, to test the isotopic fractionation of Cd during plant uptake. The Cd isotope compositions of nutrient solutions and organs of the plants were measured by multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS). The mass balance of Cd isotope yields isotope fractionations between plant and Cd source (δ114/110Cdorgans-solution) of ‑0.70‰ to ‑0.22‰ in Ricinus communis and ‑0.51‰ to ‑0.33‰ in Solanum nigrum. Moreover, Cd isotope fractionation during Cd transport from stem to leaf differs between the Cd-tolerant and -hyperaccumulator species. Based on these results, the processes (diffusion, adsorption, uptake or complexation), which may induce Cd isotope fractionation in plants, have been discussed. Overall, the present study indicates potential applications of Cd isotopes for investigating plant physiology.

  3. Combined endophytic inoculants enhance nickel phytoextraction from serpentine soil in the hyperaccumulator Noccaea caerulescens

    PubMed Central

    Visioli, Giovanna; Vamerali, Teofilo; Mattarozzi, Monica; Dramis, Lucia; Sanangelantoni, Anna M.

    2015-01-01

    This study assesses the effects of specific bacterial endophytes on the phytoextraction capacity of the Ni-hyperaccumulator Noccaea caerulescens, spontaneously growing in a serpentine soil environment. Five metal-tolerant endophytes had already been selected for their high Ni tolerance (6 mM) and plant growth promoting ability. Here we demonstrate that individual bacterial inoculation is ineffective in enhancing Ni translocation and growth of N. caerulescens in serpentine soil, except for specific strains Ncr-1 and Ncr-8, belonging to the Arthrobacter and Microbacterium genera, which showed the highest indole acetic acid production and 1-aminocyclopropane-1-carboxylic acid-deaminase activity. Ncr-1 and Ncr-8 co-inoculation was even more efficient in promoting plant growth, soil Ni removal, and translocation of Ni, together with that of Fe, Co, and Cu. Bacteria of both strains densely colonized the root surfaces and intercellular spaces of leaf epidermal tissue. These two bacterial strains also turned out to stimulate root length, shoot biomass, and Ni uptake in Arabidopsis thaliana grown in MS agar medium supplemented with Ni. It is concluded that adaptation of N. caerulescens in highly Ni-contaminated serpentine soil can be enhanced by an integrated community of bacterial endophytes rather than by single strains; of the former, Arthrobacter and Microbacterium may be useful candidates for future phytoremediation trials in multiple metal-contaminated sites, with possible extension to non-hyperaccumulator plants. PMID:26322074

  4. Fractionation of Stable Cadmium Isotopes in the Cadmium Tolerant Ricinus communis and Hyperaccumulator Solanum nigrum.

    PubMed

    Wei, Rongfei; Guo, Qingjun; Wen, Hanjie; Liu, Congqiang; Yang, Junxing; Peters, Marc; Hu, Jian; Zhu, Guangxu; Zhang, Hanzhi; Tian, Liyan; Han, Xiaokun; Ma, Jie; Zhu, Chuanwei; Wan, Yingxin

    2016-04-14

    Cadmium (Cd) isotopes provide new insights into Cd uptake, transport and storage mechanisms in plants. Therefore, the present study adopted the Cd-tolerant Ricinus communis and Cd-hyperaccumulator Solanum nigrum, which were cultured under controlled conditions in a nutrient solution with variable Cd supply, to test the isotopic fractionation of Cd during plant uptake. The Cd isotope compositions of nutrient solutions and organs of the plants were measured by multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS). The mass balance of Cd isotope yields isotope fractionations between plant and Cd source (δ(114/110)Cdorgans-solution) of -0.70‰ to -0.22‰ in Ricinus communis and -0.51‰ to -0.33‰ in Solanum nigrum. Moreover, Cd isotope fractionation during Cd transport from stem to leaf differs between the Cd-tolerant and -hyperaccumulator species. Based on these results, the processes (diffusion, adsorption, uptake or complexation), which may induce Cd isotope fractionation in plants, have been discussed. Overall, the present study indicates potential applications of Cd isotopes for investigating plant physiology.

  5. Cellular Sequestration of Cadmium in the Hyperaccumulator Plant Species Sedum alfredii1[C][W

    PubMed Central

    Tian, Shengke; Lu, Lingli; Labavitch, John; Yang, Xiaoe; He, Zhenli; Hu, Hening; Sarangi, Ritimukta; Newville, Matt; Commisso, Joel; Brown, Patrick

    2011-01-01

    Spatial imaging of cadmium (Cd) in the hyperaccumulator Sedum alfredii was investigated in vivo by laser ablation inductively coupled plasma mass spectrometry and x-ray microfluorescence imaging. Preferential Cd accumulation in the pith and cortex was observed in stems of the Cd hyperaccumulating ecotype (HE), whereas Cd was restricted to the vascular bundles in its contrasting nonhyperaccumulating ecotype. Cd concentrations of up to 15,000 μg g−1 were measured in the pith cells, which was many fold higher than the concentrations in the stem epidermis and vascular bundles in the HE plants. In the leaves of the HE, Cd was mainly localized to the mesophyll and vascular cells rather than the epidermis. The distribution pattern of Cd in both stems and leaves of the HE was very similar to calcium but not zinc, irrespective of Cd exposure levels. Extended x-ray absorption fine structure spectroscopy analysis showed that Cd in the stems and leaves of the HE was mainly associated with oxygen ligands, and a larger proportion (about 70% in leaves and 47% in stems) of Cd was bound with malic acid, which was the major organic acid in the shoots of the plants. These results indicate that a majority of Cd in HE accumulates in the parenchyma cells, especially in stems, and is likely associated with calcium pathways and bound with organic acid (malate), which is indicative of a critical role of vacuolar sequestration of Cd in the HE S. alfredii. PMID:22025609

  6. Arbuscular mycorrhizae increase the arsenic translocation factor in the As hyperaccumulating fern Pteris vittata L.

    PubMed

    Trotta, A; Falaschi, P; Cornara, L; Minganti, V; Fusconi, A; Drava, G; Berta, G

    2006-09-01

    Phytoremediation techniques are receiving more attention as decontaminating strategies. Phytoextraction makes use of plants to transfer contaminants from soil to the aboveground biomass. This research is devoted to study the effects of arbuscular mycorrhizae (AM) on growth and As hyperaccumulation in the Chinese brake fern Pteris vittata. We grew for 45 days P. vittata sporophytes, infected or not infected with the AM fungi Glomus mosseae or Gigaspora margarita, in a hydroponic system on quartz sand. As-treated plants were weekly fed with 25 ppm As. The As treatment produced a dramatic increase of As concentration in pinnae and a much lower increase in roots of both mycorrhizal and control plants. Mycorrhization increased pinnae dry weight (DW) (G. margarita = G. mosseae) and leaf area (G. margarita > G. mosseae), strongly reduced root As concentration (G. mosseae > G. margarita), and increased the As translocation factor (G. mosseae > G. margarita). The concentration of phosphorus in pinnae and roots was enhanced by both fungi (G. margarita > G. mosseae). The quantitatively different effects of the two AM fungi on plant growth as well as on As and P distribution in the fern suggest that the As hyperaccumulation in P. vittata can be optimized by a careful choice of the symbiont.

  7. Fractionation of Stable Cadmium Isotopes in the Cadmium Tolerant Ricinus communis and Hyperaccumulator Solanum nigrum

    PubMed Central

    Wei, Rongfei; Guo, Qingjun; Wen, Hanjie; Liu, Congqiang; Yang, Junxing; Peters, Marc; Hu, Jian; Zhu, Guangxu; Zhang, Hanzhi; Tian, Liyan; Han, Xiaokun; Ma, Jie; Zhu, Chuanwei; Wan, Yingxin

    2016-01-01

    Cadmium (Cd) isotopes provide new insights into Cd uptake, transport and storage mechanisms in plants. Therefore, the present study adopted the Cd-tolerant Ricinus communis and Cd-hyperaccumulator Solanum nigrum, which were cultured under controlled conditions in a nutrient solution with variable Cd supply, to test the isotopic fractionation of Cd during plant uptake. The Cd isotope compositions of nutrient solutions and organs of the plants were measured by multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS). The mass balance of Cd isotope yields isotope fractionations between plant and Cd source (δ114/110Cdorgans-solution) of −0.70‰ to −0.22‰ in Ricinus communis and −0.51‰ to −0.33‰ in Solanum nigrum. Moreover, Cd isotope fractionation during Cd transport from stem to leaf differs between the Cd-tolerant and -hyperaccumulator species. Based on these results, the processes (diffusion, adsorption, uptake or complexation), which may induce Cd isotope fractionation in plants, have been discussed. Overall, the present study indicates potential applications of Cd isotopes for investigating plant physiology. PMID:27076359

  8. Arsenic-hyperaccumulator Pteris vittata efficiently solubilized phosphate rock to sustain plant growth and As uptake.

    PubMed

    Fu, Jing-Wei; Liu, Xue; Han, Yong-He; Mei, Hanyi; Cao, Yue; de Oliveira, Letuzia M; Liu, Yungen; Rathinasabapathi, Bala; Chen, Yanshan; Ma, Lena Q

    2017-01-31

    Phosphorus (P) is one of the most important nutrients for phytoremediation of arsenic (As)-contaminated soils. In this study, we demonstrated that As-hyperaccumulator Pteris vittata was efficient in acquiring P from insoluble phosphate rock (PR). When supplemented with PR as the sole P source in hydroponic systems, P. vittata accumulated 49% and 28% higher P in the roots and fronds than the -P treatment. In contrast, non-hyperaccumulator Pteris ensiformis was unable to solubilize P from PR. To gain insights into PR solubilization by plants, organic acids in plant root exudates were analyzed by HPLC. The results showed that phytic acid was the predominant (>90%) organic acid in P. vittata root exudates whereas only oxalic acid was detected in P. ensiformis. Moreover, P. vittata secreted more phytic acid in -P and PR treatments. Compared to oxalic acid, phytic acid was more effective in solubilizing PR, suggesting that phytic acid was critical for PR utilization. Besides, secretion of phytic acid by P. vittata was not inhibited by arsenate. Our data indicated that phytic acid played an important role in efficient use of insoluble PR by P. vittata, shedding light on using insoluble PR to enhance phytoremediation of As-contaminated soils.

  9. The impact of Ni on the physiology of a Mediterranean Ni-hyperaccumulating plant.

    PubMed

    Roccotiello, Enrica; Serrano, Helena Cristina; Mariotti, Mauro Giorgio; Branquinho, Cristina

    2016-06-01

    High nickel (Ni) levels exert toxic effects on plant growth and plant water content, thus affecting photosynthesis. In a pot experiment, we investigated the effect of the Ni concentration on the physiological characteristics of the Ni hyperaccumulator Alyssoides utriculata when grown on a vermiculite substrate in the presence of different external Ni concentrations (0-500 mg Ni L(-1)). The results showed that the Ni concentration was higher in leaves than in roots, as evidenced by a translocation factor = 3 and a bioconcentration factor = 10. At the highest concentration tested (500 mg Ni L(-1)), A. utriculata accumulated 1100 mg Ni per kilogram in its leaves, without an effects on its biomass. Plant water content increased significantly with Ni accumulation. Ni treatment did not, or only slightly, affected chlorophyll fluorescence parameters. The photosynthetic efficiency (FV/FM) of A. utriculata was stable between Ni treatments (always ≥ 0.8) and the photosynthetic performance of the plant under Ni stress remained high (performance index = 1.5). These findings support that A. utriculata has several mechanisms to avoid severe damage to its photosynthetic apparatus, confirming the tolerance of this species to Ni under hyperaccumulation.

  10. Cellular Sequestration of Cadmium in the Hyperaccumulator Plant Species Sedum alfredii

    SciTech Connect

    Tian, Shengke; Lu, Lingli; Labavitch, John M.; Yang, Xiaoe; He, Zhenli; Hu, Hening; Sarangi, Ritimukta; Newville, Matt; Commisso, Joel; Brown, Patrick Hugh

    2012-07-23

    Spatial imaging of cadmium (Cd) in the hyperaccumulator Sedum alfredii was investigated in vivo by laser ablation inductively coupled plasma mass spectrometry and x-ray microfluorescence imaging. Preferential Cd accumulation in the pith and cortex was observed in stems of the Cd hyperaccumulating ecotype (HE), whereas Cd was restricted to the vascular bundles in its contrasting nonhyperaccumulating ecotype. Cd concentrations of up to 15,000 {micro}g g{sup -1} were measured in the pith cells, which was many fold higher than the concentrations in the stem epidermis and vascular bundles in the HE plants. In the leaves of the HE, Cd was mainly localized to the mesophyll and vascular cells rather than the epidermis. The distribution pattern of Cd in both stems and leaves of the HE was very similar to calcium but not zinc, irrespective of Cd exposure levels. Extended x-ray absorption fine structure spectroscopy analysis showed that Cd in the stems and leaves of the HE was mainly associated with oxygen ligands, and a larger proportion (about 70% in leaves and 47% in stems) of Cd was bound with malic acid, which was the major organic acid in the shoots of the plants. These results indicate that a majority of Cd in HE accumulates in the parenchyma cells, especially in stems, and is likely associated with calcium pathways and bound with organic acid (malate), which is indicative of a critical role of vacuolar sequestration of Cd in the HE S. alfredii.

  11. Waste or substrate for metal hyperaccumulating plants - The potential of phytomining on waste incineration bottom ash.

    PubMed

    Rosenkranz, Theresa; Kisser, Johannes; Wenzel, Walter W; Puschenreiter, Markus

    2017-01-01

    Phytomining could represent an innovative low-cost technology for the selective recovery of valuable trace elements from secondary resources. In this context the potential of phytomining from waste incineration bottom ash was tested in a pot experiment. Fresh bottom ash was acidified, leached to reduce salinity and amended with organic material to obtain a suitable substrate for plant growth. Two hyperaccumulator species, Alyssum serpyllifolium subsp. lusitanicum and Sedum plumbizincicola as well as three metal tolerant species, Brassica napus, B. juncea and Nicotiana tabacum were tested for their phytomining potential on the pre-treated and amended bottom ashes from municipal solid waste and hazardous waste incineration. The hyperaccumulators had severe difficulties to establish on the bottom ash and to produce sufficient biomass, likely due to salinity and Cu toxicity. Nevertheless, concentrations of Ni in A. serpyllifolium and Zn in S. plumbizincicola were high, but total metal removal was limited by the low biomass production and was clearly less than on metalliferous soils. The Brassica species proved to be more tolerant to salinity and high Cu concentrations and produced considerably higher biomass, but total metal removal was limited by rather low shoot concentrations. The observed limitations of the phytomining process along with currently low market prices of Ni and Zn suggest that further optimisation of the process is required in order to make phytomining economically feasible on the tested waste incineration bottom ashes.

  12. Nickel and Manganese Accumulation, Interaction and Localization in Leaves of the Ni Hyperaccumulators Alyssum murale and Alyssum corsicum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genus Alyssum contains >50 Ni hyperaccumulator species; many can achieve 3% Ni in dry leaf. In soils with normal Mn levels, Alyssum trichome bases were observed previously to accumulate Ni and Mn to high levels. Here we report concentration and localization patterns in A. murale and A. corsicum...

  13. Selenium biofortification of broccoli and carrots grown in soil amended with Se-enriched hyperaccumulator Stanleya pinnata

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Amending soils with Se-hyperaccumulator plant derived sources of selenium (Se) may be useful for increasing Se content in food crops in Se-deficient regions of the world. In this study, we evaluated total Se and the different chemical species of Se in broccoli and carrots grown in soils amended with...

  14. Potential hyperaccumulation of Pb, Zn, Cu and Cd in endurant plants distributed in an old smeltery, northeast China

    NASA Astrophysics Data System (ADS)

    Cui, Shuang; Zhou, Qixing; Chao, Lei

    2007-01-01

    The absorption and accumulation of Pb, Zn, Cu and Cd in some endurant weed plant species that survived in an old smeltery in Liaoning, China, were systematically investigated. Potential hyperaccumulative characteristics of these species were also discussed. The results showed that metal accumulation in plants differed with species, tissues and metals. Endurant weed plants growing in this contaminated site exhibited high metal adaptability. Both the metal exclusion and detoxification tolerance strategies were involved in the species studied. Seven species for Pb and four species for Cd were satisfied for the concentration time level standard for hyperaccumulator. Considering translocation factor (TF) values, one species for Pb, seven species for Zn, two species for Cu and five species for Cd possessed the characteristic of hyperaccumulator. Particularly, Abutilon theophrasti Medic, exhibited strong accumulative ability to four heavy metals. Although enrichment coefficients of all samples were lesser than 1 and the absolute concentrations didn’t reach the standard, species mentioned above were primarily believed to be potential hyperaccumulators.

  15. Exogenous cytokinin treatments of a Ni hyper-accumulator, Alyssum murale, grown in a serpentine soil: Implications for phytoextraction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Application of exogenous plant growth regulators was examined as a viable technique to increase the efficiency of plant metal phytoextraction from contaminated soils. The aim of this study was to investigate the alteration of Ni phytoextraction by Alyssum murale, a Ni hyperaccumulator, following the...

  16. Spatial Imaging, Speciation, and Quantification of Selenium in theHyperaccumulator Plants Astragalus bisulcatus and Stanleya pinnata

    SciTech Connect

    Freeman, J.L.; Zhang, L.H.; Marcus, M.A.; Fakra, S.; McGrath,S.P.; Pilon-Smits, E.A.H.

    2006-09-01

    Astragalus bisulcatus and Stanleya pinnata hyperaccumulate selenium (Se) up to 1% of plant dry weight. In the field, Se was mostly present in the young leaves and reproductive tissues of both hyperaccumulators. Microfocused scanning x-ray fluorescence mapping revealed that Se was hyperaccumulated in trichomes in young leaves of A. bisulcatus. None of 10 other elements tested were accumulated in trichomes. Micro x-ray absorption spectroscopy and liquid chromatography-mass spectrometry showed that Se in trichomes was present in the organic forms methylselenocysteine (MeSeCys; 53%) and {gamma}-glutamyl-MeSeCys (47%). In the young leaf itself, there was 30% inorganic Se (selenate and selenite) in addition to 70% MeSeCys. In young S. pinnata leaves, Se was highly concentrated near the leaf edge and surface in globular structures that were shown by energy-dispersive x-ray microanalysis to be mainly in epidermal cells. Liquid chromatography-mass spectrometry revealed both MeSeCys (88%) and selenocystathionine (12%) inside leaf edges. In contrast, both the Se accumulator Brassica juncea and the nonaccumulator Arabidopsis thaliana accumulated Se in their leaf vascular tissues and mesophyll cells. Se in hyperaccumulators appears to be mobile in both the xylem and phloem because Se-treated S. pinnata was found to be highly toxic to phloem-feeding aphids, and MeSeCys was present in the vascular tissues of a S. pinnata young leaf petiole as well as in guttation fluid. The compartmentation of organic selenocompounds in specific storage areas in the plant periphery appears to be a unique property of Se hyperaccumulators. The high concentration of Se in the plant periphery may contribute to Se tolerance and may also serve as an elemental plant defense mechanism.

  17. Identification of target genes and processes involved in erucic acid accumulation during seed development in the biodiesel feedstock Pennycress (Thlaspi arvense L.).

    PubMed

    Claver, Ana; Rey, Raquel; López, M Victoria; Picorel, Rafael; Alfonso, Miguel

    2017-01-01

    We studied erucic acid accumulation in the biodiesel feedstock Pennycress (Thlaspi arvense L.) as a first step towards the development of a sustainable strategy for biofuel production in the EU territory. To that end, two inbred Pennycress lines of European origin, "NASC" and "French," were cultivated in a controlled chamber and in experimental field plots, and their growth, seed production and seed oil characteristics analyzed. Differences in some agronomical traits like vernalization (winter-French versus spring-NASC), flowering time (delayed in the French line) and seed production (higher in the French line) were detected. Both lines showed a high amount (35-39%) of erucic acid (22:1(Δ13)) in their seed oil. Biochemical characterization of the Pennycress seed oil indicated that TAG was the major reservoir of 22:1(Δ13). Incorporation of 22:1(Δ13) to TAG occurred very early during seed maturation, concomitant with a decrease of desaturase activity. This change in the acyl fluxes towards elongation was controlled by different genes at different levels. TaFAE1 gene, encoding the fatty acid elongase, seemed to be controlled at the transcriptional level with high expression at the early stages of seed development. On the contrary, the TaFAD2 gene that encodes the Δ12 fatty acid desaturase or TaDGAT1 that catalyzes TAG biosynthesis were controlled post-transcriptionally. TaWRI1, the master regulator of seed-oil biosynthesis, showed also high expression at the early stages of seed development. Our data identified genes and processes that might improve the biotechnological manipulation of Pennycress seeds for high-quality biodiesel production.

  18. Selenium uptake by edible oyster mushrooms (Pleurotus sp.) from selenium-hyperaccumulated wheat straw.

    PubMed

    Bhatia, Poonam; Prakash, Ranjana; Prakash, N Tejo

    2013-01-01

    In an effort to produce selenium (Se)-fortifying edible mushrooms, five species of oyster mushroom (Pleurotus sp.), were cultivated on Se-rich wheat straw collected from a seleniferous belt of Punjab, India. Total selenium was analyzed in the selenium hyperaccumulated wheat straw and the fruiting bodies. Significantly high levels (p<0.0001) of Se uptake were observed in fruiting bodies of all mushrooms grown on Se-rich wheat straw. To the best of our knowledge, accumulation and quantification of selenium in mushrooms has hitherto not been reported with substrates naturally enriched with selenium. The results demonstrate the potential of selenium-rich agricultural residues as substrates for production of Se-enriched mushrooms and the ability of different species of oyster mushrooms to absorb and fortify selenium. The study envisages potential use of selenium-rich agricultural residues towards cultivation of Se-enriched mushrooms for application in selenium supplementation or neutraceutical preparations.

  19. Nickel localization on tissues of hyperaccumulator species of phyllanthus L. (Euphorbiaceae) from ultramafic areas of Cuba.

    PubMed

    Berazaín, R; de la Fuente, V; Sánchez-Mata, D; Rufo, L; Rodríguez, N; Amils, R

    2007-01-01

    Two species of perennial Phyllanthus (Euphorbiaceae) (Phyllanthus orbicularis and Phyllanthus discolor, both endemic to ultramafic areas of Cuba, and their natural hybrid, Phyllanthus xpallidus) were selected for metal localization microanalysis. Different plant tissues were analyzed by X-ray fluorescence, inductively coupled plasma-atomic emission spectroscopy, and scanning electron microscopy coupled with an energy-dispersive X-ray probe. All of the studied taxa are nickel (Ni) hyperaccumulators and significant concentrations of this element were found in different leaf and stem tissues. The highest Ni content was found in the laticifer tubes, whereas leaf epidermis Ni content resulted to be much more relevant in terms of total metal storage. Calcium and magnesium were found more evenly distributed in leaf and stem tissues.

  20. Phytoremediation of cadmium-contaminated farmland soil by the hyperaccumulator Beta vulgaris L. var. cicla.

    PubMed

    Song, Xueying; Hu, Xiaojun; Ji, Puhui; Li, Yushuang; Chi, Guangyu; Song, Yufang

    2012-04-01

    A field study was conducted to evaluate the phytoremediation efficiency of cadmium (Cd) contaminated soil utilizing the Cd hyperaccumulator Beta vulgaris L. var. cicla during one growing season (about 2 months) on farmland in Zhangshi Irrigation Area, the representative wastewater irrigation area in China. Results showed that B. vulgaris L. var. cicla is a promising plant in the phytoremediation of Cd contaminated farmland soil. The maximum of Cd phytoremediation efficiency by B. vulgaris L. var. cicla reached 144.6 mg/ha during one growing season. Planting density had a significant effect on the plant biomass and the overall Cd phytoremediation efficiency (p < 0.05). The amendment of organic manure promoted the biomass increase of B. vulgaris L. var. cicla (p < 0.05) but inhibited the Cd phytoremediation efficiency.

  1. Role of transpiration in arsenic accumulation of hyperaccumulator Pteris vittata L.

    PubMed

    Wan, Xiao-ming; Lei, Mei; Chen, Tong-bin; Yang, Jun-xing; Liu, Hong-tao; Chen, Yang

    2015-11-01

    Mechanisms of Pteris vittata L. to hyperaccumulate arsenic (As), especially the efficient translocation of As from rhizoids to fronds, are not clear yet. The present study aims to investigate the role of transpiration in the accumulation of As from the aspects of transpiration regulation and ecotypic difference. Results showed that As accumulation of P. vittata increased proportionally with an increase in the As exposure concentration. Lowering the transpiration rate by 28∼67% decreased the shoot As concentration by 19∼56%. Comparison of As distribution under normal treatment and shade treatment indicated that transpiration determines the distribution pattern of As in pinnae. In terms of the ecotypic difference, the P. vittata ecotype from moister and warmer habitat had 40% higher transpiration and correspondingly 40% higher shoot As concentration than the ecotype from drier and cooler habitat. Results disclosed that transpiration is the main driver for P. vittata to accumulate and re-distribute As in pinnae.

  2. Chelator effects on bioconcentration and translocation of cadmium by hyperaccumulators, Tagetes patula and Impatiens walleriana.

    PubMed

    Wei, Jhen-Lian; Lai, Hung-Yu; Chen, Zueng-Sang

    2012-10-01

    French marigold (Tagetes patula) and impatiens (Impatiens walleriana) can act as hyperaccumulator plants for removal of cadmium (Cd) from contaminated sites. In this study, an exponential decay model was used to predict the maximum removal of Cd from artificially spiked soils by impatiens. Application of a chelator, EDTA, was also assessed for effects on the bioconcentration (BCF) and translocation (TF) factors of the two species with four replicates. Exposure to Cd significantly decreased the biomass of two plant species. Impatiens and French marigold accumulated Cd at a rate of 200-1200 mg Cd kg(-1) in shoots, with BCFs and TFs of 8.5-15 and 1.7-2.6, respectively.

  3. Leaf-age and soil-plant relationships: key factors for reporting trace-elements hyperaccumulation by plants and design applications.

    PubMed

    Losfeld, Guillaume; L'Huillier, Laurent; Fogliani, Bruno; Mc Coy, Stéphane; Grison, Claude; Jaffré, Tanguy

    2015-04-01

    Relationships between the trace-elements (TE) content of plants and associated soil have been widely investigated especially to understand the ecology of TE hyperaccumulating species to develop applications using TE phytoextraction. Many studies have focused on the possibility of quantifying the soil TE fraction available to plants, and used bioconcentration (BC) as a measure of the plants ability to absorb TE. However, BC only offers a static view of the dynamic phenomenon of TE accumulation. Accumulation kinetics are required to fully account for TE distributions in plants. They are also crucial to design applications where maximum TE concentrations in plant leaves are needed. This paper provides a review of studies of BC (i.e. soil-plant relationships) and leaf-age in relation to TE hyperaccumulation. The paper focuses of Ni and Mn accumulators and hyperaccumulators from New Caledonia who were previously overlooked until recent Ecocatalysis applications emerged for such species. Updated data on Mn hyperaccumulators and accumulators from New Caledonia are also presented and advocate further investigation of the hyperaccumulation of this element. Results show that leaf-age should be considered in the design of sample collection and allowed the reclassification of Grevillea meisneri known previously as a Mn accumulator to a Mn hyperaccumulator.

  4. Hydroponic phytoremediation of Cd, Cr, Ni, As, and Fe: can Helianthus annuus hyperaccumulate multiple heavy metals?

    PubMed

    January, Mary C; Cutright, Teresa J; Van Keulen, Harry; Wei, Robert

    2008-01-01

    Sundance sunflowers were subjected to contaminated solutions containing 3, 4, or 5 heavy metals, with and without EDTA. The sunflowers exhibited a metal uptake preference of Cd=Cr>Ni, Cr>Cd>Ni>As and Fe>As>Cd>Ni>Cr without EDTA and Cr>Cd>Ni, Fe>As>Cd>Cr>Ni with EDTA. As uptake was not affected by other metals, but it decreased Cd and Ni concentration in the stems. The presence of Fe improved the translocation of the other metals regardless of whether EDTA was present. In general, EDTA served as a hindrance to metal uptake. For the experiment with all five heavy metals, EDTA decreased Cd in the roots and stems from 2.11 to 1.36 and from 2.83 to 2.3 2mg g(-1) biomass, respectively. For the same conditions, Ni in the stems decreased from 1.98 to 0.94 mg g(-1) total metal uptake decreased from 14.95 mg to 13.89 mg, and total biomass decreased from 2.38 g to 1.99 g. These results showed an overall negative effect in addition of EDTA. However it is unknown whether the negative effect was due to toxicity posed by EDTA or the breaking of phytochelatin-metal bonds. The most important finding was the ability of Sundance sunflowers to achieve hyperaccumulator status for both As and Cd under all conditions studied. Ni hyperaccumulator status was only achieved in the presence of three metals without EDTA.

  5. A comprehensive set of transcript sequences of the heavy metal hyperaccumulator Noccaea caerulescens

    PubMed Central

    Lin, Ya-Fen; Severing, Edouard I.; te Lintel Hekkert, Bas; Schijlen, Elio; Aarts, Mark G. M.

    2014-01-01

    Noccaea caerulescens is an extremophile plant species belonging to the Brassicaceae family. It has adapted to grow on soils containing high, normally toxic, concentrations of metals such as nickel, zinc, and cadmium. Next to being extremely tolerant to these metals, it is one of the few species known to hyperaccumulate these metals to extremely high concentrations in their aboveground biomass. In order to provide additional molecular resources for this model metal hyperaccumulator species to study and understand the mechanism of adaptation to heavy metal exposure, we aimed to provide a comprehensive database of transcript sequences for N. caerulescens. In this study, 23,830 transcript sequences (isotigs) with an average length of 1025 bp were determined for roots, shoots and inflorescences of N. caerulescens accession “Ganges” by Roche GS-FLEX 454 pyrosequencing. These isotigs were grouped into 20,378 isogroups, representing potential genes. This is a large expansion of the existing N. caerulescens transcriptome set consisting of 3705 unigenes. When translated and compared to a Brassicaceae proteome set, 22,232 (93.2%) of the N. caerulescens isotigs (corresponding to 19,191 isogroups) had a significant match and could be annotated accordingly. Of the remaining sequences, 98 isotigs resembled non-plant sequences and 1386 had no significant similarity to any sequence in the GenBank database. Among the annotated set there were many isotigs with similarity to metal homeostasis genes or genes for glucosinolate biosynthesis. Only for transcripts similar to Metallothionein3 (MT3), clear evidence for an additional copy was found. This comprehensive set of transcripts is expected to further contribute to the discovery of mechanisms used by N. caerulescens to adapt to heavy metal exposure. PMID:24999345

  6. Antioxidant responses of hyper-accumulator and sensitive fern species to arsenic.

    PubMed

    Srivastava, Mrittunjai; Ma, Lena Q; Singh, Nandita; Singh, Shraddha

    2005-05-01

    Plant species capable of hyper-accumulating heavy metals are of considerable interest for phytoremediation, and differ in their ability to accumulate metals from the environment. This work aims to examine (i) arsenic accumulation in three fern species [Chinese brake fern (Pteris vittata L.), slender brake fern (Pteris ensiformis Burm. f.), and Boston fern (Nephrolepis exaltata L.)], which were exposed to 0, 150, or 300 muM of arsenic (Na(2)HAsO(4).7H(2)O), and (ii) the role of anti-oxidative metabolism in arsenic tolerance in these fern species. Arsenic accumulation increased with an increase in arsenic concentration in the growth medium, the most being found in P. vittata fronds showing no toxicity symptoms. In addition, accumulation was highest in the fronds, followed by the rhizome, and finally the roots, in all three fern species. Thiobarbituric acid-reacting substances, indicators of stress in plants, were found to be lowest in P. vittata, which corresponds with its observed tolerance to arsenic. All three ferns responded differentially to arsenic exposure in terms of anti-oxidative defence. Higher levels of superoxide dismutase, catalase, and ascorbate peroxidase were observed in P. vittata than in P. ensiformis and N. exaltata, showing their active involvement in the arsenic detoxification mechanism. However, no significant increase was observed in either guaiacol peroxides or glutathione reductase in arsenic-treated P. vittata. Higher activity of anti-oxidative enzymes and lower thiobarbituric acid-reacting substances in arsenic-treated P. vittata correspond with its arsenic hyper-accumulation and no symptoms of toxicity.

  7. Phytoremediation of uranium-contaminated soils: Role of organic acids in triggering uranium hyperaccumulation in plants

    SciTech Connect

    Huang, J.W.; Blaylock, M.J.; Kapulnik, Y.; Ensley, B.D.

    1998-07-01

    Uranium phytoextraction, the use of plants to extract U from contaminated soils, is an emerging technology. The authors report on the development of this technology for the cleanup of U-contaminated soils. In this research, they investigated the effects of various soil amendments on U desorption from soil to soil solution, studied the physiological characteristics of U uptake and accumulation in plants, and developed techniques to trigger U hyperaccumulation in plants. A key to the success of U phytoextraction is to increase soil U availability to plants. The authors have found that some organic acids can be added to soils to increase U desorption from soil to soil solution and to trigger a rapid U accumulation in plants. Of the organic acids (acetic acid, citric acid, and malic acid) tested, citric acid was the most effective in enhancing U accumulation in plants. Shoot U concentrations of Brassica juncea and Brassica chinensis grown in a U-contaminated soil increased from less than 5 mg kg{sup {minus}1} to more than 5,000 mg kg{sup {minus}1} in citric acid-treated soils. To their knowledge, this is the highest shoot U concentration reported for plants grown on U-contaminated soils. Using this U hyperaccumulation technique, they are now able to increase U accumulation in shoots of selected plant species grown in two U-contaminated soils by more than 1,000-fold within a few days. The results suggest that U phytoextraction may provide an environmentally friendly alternative for the cleanup of U-contaminated soils.

  8. A Newly Identified Passive Hyperaccumulator Eucalyptus grandis × E. urophylla under Manganese Stress

    PubMed Central

    Xie, Qingqing; Li, Zhenji; Yang, Limin; Lv, Jing; Jobe, Timothy O.; Wang, Qiuquan

    2015-01-01

    Manganese (Mn) is an essential micronutrient needed for plant growth and development, but can be toxic to plants in excess amounts. However, some plant species have detoxification mechanisms that allow them to accumulate Mn to levels that are normally toxic, a phenomenon known as hyperaccumulation. These species are excellent candidates for developing a cost-effective remediation strategy for Mn-polluted soils. In this study, we identified a new passive Mn-hyperaccumulator Eucalyptus grandis × E. urophylla during a field survey in southern China in July 2010. This hybrid can accumulate as much as 13,549 mg/kg DW Mn in its leaves. Our results from Scanning Electron Microscope (SEM) X-ray microanalysis indicate that Mn is distributed in the entire leaf and stem cross-section, especially in photosynthetic palisade, spongy mesophyll tissue, and stem xylem vessels. Results from size-exclusion chromatography coupled with ICP-MS (Inductively coupled plasma mass spectrometry) lead us to speculate that Mn associates with relatively high molecular weight proteins and low molecular weight organic acids, including tartaric acid, to avoid Mn toxicity. Our results provide experimental evidence that both proteins and organic acids play important roles in Mn detoxification in Eucalyptus grandis × E. urophylla. The key characteristics of Eucalyptus grandis × E. urophylla are an increased Mn translocation facilitated by transpiration through the xylem to the leaves and further distribution throughout the leaf tissues. Moreover, the Mn-speciation profile obtained for the first time in different cellular organelles of Eucalyptus grandis × E. urophylla suggested that different organelles have differential accumulating abilities and unique mechanisms for Mn-detoxification. PMID:26327118

  9. Enhancement of Cd phytoextraction by hyperaccumulator Sedum alfredii using electrical field and organic amendments.

    PubMed

    Xiao, Wendan; Li, Dan; Ye, Xuezhu; Xu, Haizhou; Yao, Guihua; Wang, Jingwen; Zhang, Qi; Hu, Jing; Gao, Na

    2017-02-01

    The combined use of organic amendment-assisted phytoextraction and electrokinetic remediation to decontaminate Cd-polluted soil was demonstrated in a laboratory-scale experiment. The plant species selected was the hyperaccumulator Sedum alfredii. Prior to the pot experiment, the loamy soil was treated with 15 g kg(-1) of pig manure compost, 10 g kg(-1) of humic acid, or 5 mmol kg(-1) of EDTA, and untreated soil without application of any amendment was the control. Two conditions were applied to each treatment: no voltage (without an electrical field) and a direct current (DC) electrical field (1 V cm(-1) with switching polarity every day). Results indicated that Cd concentrations in S. alfredii were significantly (p < 0.05) increased by application of the electrical field and soil amendments (pig manure compost, humic acid, and EDTA). By switching the polarity of the DC electrical field, significant pH variation from anode to cathode can be avoided, and no significant impact was observed on shoot biomass production. Electrical field application increased DTPA-extractable Cd in soils and the Cd accumulation in shoots by 6.06-15.64 and 24.53-52.31%, respectively. The addition of pig manure compost and humic acid enhanced shoot Cd accumulation by 1.54- to 1.92- and 1.38- to 1.64-fold because of their simultaneous enhancement of Cd concentration in shoots and biomass production. However, no enhancement of Cd accumulation was found in the EDTA treatment, which can be ascribed to the inhibition of plant growth caused by EDTA. In conclusion, pig manure compost or humic acid addition in combination with the application of a switched-polarity DC electrical field could significantly enhance Cd phytoextraction by hyperaccumulator S. alfredii.

  10. Hyperaccumulator oilcake manure as an alternative for chelate-induced phytoremediation of heavy metals contaminated alluvial soils.

    PubMed

    Mani, Dinesh; Kumar, Chitranjan; Patel, Niraj Kumar

    2015-01-01

    The ability of hyperaccumulator oilcake manure as compared to chelates was investigated by growing Calendula officinalis L for phytoremediation of cadmium and lead contaminated alluvial soil. The combinatorial treatment T6 [2.5 g kg(-1) oilcake manure+5 mmol kg(-1) EDDS] caused maximum cadmium accumulation in root, shoot and flower up to 5.46, 4.74 and 1.37 mg kg(-1) and lead accumulation up to 16.11, 13.44 and 3.17 mg kg(-1), respectively at Naini dump site, Allahabad (S3). The treatment showed maximum remediation efficiency for Cd (RR=0.676%) and Pb (RR=0.202%) at Mumfordganj contaminated site (S2). However, the above parameters were also observed at par with the treatment T5 [2.5 g kg(-1) oilcake manure +2 g kg(-1) humic acid]. Applied EDDS altered chlorophyll-a, chlorophyll-b, and carotene contents of plants while application of oilcake manure enhanced their contents in plant by 3.73-8.65%, 5.81-17.65%, and 7.04-17.19%, respectively. The authors conclude that Calendula officinalis L has potential to be safely grown in moderately Cd and Pb-contaminated soils and application of hyperaccumulator oilcake manure boosts the photosynthetic pigments of the plant, leading to enhanced clean-up of the cadmium and lead-contaminated soils. Hence, the hyperaccumulator oilcake manure should be preferred over chelates for sustainable phytoremediation through soil-plant rhizospheric process.

  11. Quantitative micro-PIXE comparison of elemental distribution in Ni-hyperaccumulating and non-accumulating genotypes of Senecio coronatus

    NASA Astrophysics Data System (ADS)

    Mesjasz-Przybyłowicz, J.; Przybyłowicz, W. J.; Prozesky, V. M.; Pineda, C. A.

    1997-07-01

    The Ni hyperaccumulator, plant species Senecio coronatus (Thunb.) Harv., Asteraceae is an example of plant adaptation mechanisms to different ecological conditions. This widespread species can inter alia be found on serpentine outcrops and the genotypes growing in serpentine soils show different ways of adaptation. The populations from two distant localities take up and translocate Ni in concentrations which are normally phytotoxic, while plants growing on a different site, in the vicinity of another hyperaccumulating species, absorb amounts which are typical for most of the plants found on serpentine soils. The NAC nuclear microprobe was used to compare the distribution of Ni and other elements in selected organs and cells with simultaneous use of PIXE and proton BackScattering (BS). Quantitative maps of stems showed large differences in concentrations and distributions of major and trace elements. In hyperaccumulating genotypes Ni is present everywhere within stem tissues, but the highest concentrations were found in the epidermis, cortex and phloem. In non-accumulating plants Ni was concentrated in the phloem. In the leaf epidermis Ni was concentrated in the cell walls for both accumulating and non-accumulating plants. These results suggest that biochemical diversity is more than morphological, because investigated genotypes belong to the same taxon.

  12. Characterization of Zinc and Cadmium Hyperaccumulation in Three Noccaea (Brassicaceae) Populations from Non-metalliferous Sites in the Eastern Pyrenees

    PubMed Central

    Martos, Soledad; Gallego, Berta; Sáez, Llorenç; López-Alvarado, Javier; Cabot, Catalina; Poschenrieder, Charlotte

    2016-01-01

    The Southern slope of the Pyrenees is the meridional limit for the distribution of several Noccaea populations. However, the systematic description of these populations and their hyperaccumulation mechanisms are not well established. Morphological and genetic analysis (ITS and 3 chloroplast regions) were used to identify Noccaea populations localized on non-metallicolous soils during a survey in the Catalonian Pyrenees. Cd and Zn concentrations were analyzed in soils and plants both sampled in the field and grown hydroponically. The expression of selected metal transporter genes was assessed by quantitative PCR. The populations were identified as Noccaea brachypetala (Jord.) F.K. Mey by conspicuous morphological traits. Principal component analysis provided a clear separation among N. brachypetala, Noccaea caerulescens J. Presl & C. Presl and Noccaea occitanica (Jord.) F.K. Mey., three Noccaea species reported in the Pyrenees. Contrastingly, ITS and cpDNA analyses were unable to clearly differentiate these taxa. Differences in the expression of the metal transporter genes HMA3, HMA4, and MTP1 between N. caerulescens and N. brachypetala, and those amongst the N. brachypetala populations suggest differences in the strategies for handling enhanced Cd and Zn availability. This is the first report demonstrating Cd and Zn hyperaccumulation by N. brachypetala both in the field and in hydroponics. This comprehensive study based on taxonomic, molecular, and physiological data allows both the correct identification of this species and the characterization of population differences in hyperaccumulation and tolerance of Zn and Cd. PMID:26904085

  13. Phytomining of valuable metals from waste incineration residues using hyperaccumulator plants

    NASA Astrophysics Data System (ADS)

    Rosenkranz, Theresa; Kisser, Johannes; Gattringer, Heinz; Iordanopoulos-Kisser, Monika; Puschenreiter, Markus

    2015-04-01

    Worldwide the availability of primary sources of certain economically important metals is decreasing, resulting in high supply risks and increasing prices for this materials. Therefore, an alternative way of retrieving these high valuable technical metals is the recycling and use of anthropogenic secondary sources, such as waste incineration residues. Phytomining offers an environmentally sound and cheap technology to recover such metals from secondary sources. Thus, the aim of our research work is to investigate the potential of phytomining from waste incineration slags by growing metal hyperaccumulating plants on this substrates and use the metal enriched biomass as a bio-ore. As a first stage, material from Vienna's waste incineration plants was sampled and analyzed. Residues from municipal wastes as well as residues from hazardous waste incineration and sewage sludge incineration were analyzed. In general, the slags can be characterized by a very high pH, high salinity and high heavy metal concentrations. Our work is targeting the so-called critical raw materials defined by the European Commission in 2014. Thus, the target metal species in our project are amongst others cobalt, chromium, antimony, tungsten, gallium, nickel and selected rare earth elements. This elements are present in the slags at moderate to low concentrations. In order to optimize the substrate for plant growth the high pH and salt content as well as the low nitrogen content in the slags need to be controlled. Thus, different combinations of amendments, mainly from the waste industry, as well as different acidifying agents were tested for conditioning the substrate. Washing the slags with diluted nitric acid turned out to be effective for lowering the pH. The acid treated substrate in combination with material from mechanical biological waste treatment and biochar, is currently under investigation in a greenhouse pot experiment. The experimental setup consists of a full factorial design

  14. Evaluation of specimen preparation techniques for micro-PIXE localisation of elements in hyperaccumulating plants

    NASA Astrophysics Data System (ADS)

    Kachenko, Anthony G.; Siegele, Rainer; Bhatia, Naveen P.; Singh, Balwant; Ionescu, Mihail

    2008-04-01

    Hybanthus floribundus subsp. floribundus, a rare Australian Ni-hyperaccumulating shrub and Pityrogramma calomelanos var. austroamericana, an Australian naturalized As-hyperaccumulating fern are promising species for use in phytoremediation of contaminated sites. Micro-proton-induced X-ray emission (μ-PIXE) spectroscopy was used to map the elemental distribution of the accumulated metal(loid)s, Ca and K in leaf or pinnule tissues of the two plant species. Samples were prepared by two contrasting specimen preparation techniques: freeze-substitution in tetrahydrofuran (THF) and freeze-drying. The specimens were analysed to compare the suitability of each technique in preserving (i) the spatial elemental distribution and (ii) the tissue structure of the specimens. Further, the μ-PIXE results were compared with concentration of elements in the bulk tissue obtained by ICP-AES analysis. In H. floribundus subsp. floribundus, μ-PIXE analysis revealed Ni, Ca and K concentrations in freeze-dried leaf tissues were at par with bulk tissue concentrations. Elemental distribution maps illustrated that Ni was preferentially localised in the adaxial epidermal tissues (1% DW) and least concentration was found in spongy mesophyll tissues (0.53% DW). Conversely, elemental distribution maps of THF freeze-substituted tissues indicated significantly lower Ni, Ca and K concentrations than freeze-dried specimens and bulk tissue concentrations. Moreover, Ni concentrations were uniform across the whole specimen and no localisation was observed. In P. calomelanos var. austroamericana freeze-dried pinnule tissues, μ-PIXE revealed statistically similar As, Ca and K concentrations as compared to bulk tissue concentrations. Elemental distribution maps showed that As localisation was relatively uniform across the whole specimen. Once again, THF freeze-substituted tissues revealed a significant loss of As compared to freeze-dried specimens and the concentrations obtained by bulk tissue analysis

  15. Life history variation in the heavy metal tolerant plant Thlaspi caerulescens growing in a network of contaminated and noncontaminated sites in southern France: role of gene flow, selection and phenotypic plasticity.

    PubMed

    Jiménez-Ambriz, Georgina; Petit, Christophe; Bourrié, Isabelle; Dubois, Sophie; Olivieri, Isabelle; Ronce, Ophélie

    2007-01-01

    * Here we explore life history differences in a set of neighbouring metallicolous and nonmetallicolous populations of the heavy metal tolerant plant Thlaspi caerulescens. * We contrasted data from field observations and from a common garden experiment, in which soil zinc (Zn) concentration and light availability were manipulated, and data on microsatellite molecular variation. * The two ecotypes showed few differences in life history in the field, but large differences in their response to Zn concentration in the common garden. Soil toxicity affected most characters in nonmetallicolous plants, while it had no effect on metallicolous plants. The two ecotypes responded similarly to light. Genetic differentiation for quantitative characters between ecotypes contrasted with the absence of differentiation for microsatellites. Conversely, populations of the same ecotype showed similar responses to Zn, despite their high differentiation for molecular markers. * We conclude that divergent selection related to soil toxicity has had a predominant role in shaping life history differences between ecotypes, gene flow weakly opposing local adaptation despite geographical proximity.

  16. Effect of soil pH on as hyperaccumulation capacity in fern species, Pityrogramma calomelanos.

    PubMed

    Anh, B T Kim; Kim, D D; Kuschk, P; Tua, T V; Hue, N T; Minh, N N

    2013-03-01

    Arsenic uptake by hyperaccumulator plant species depends on many different environmental factors. Soil pH is one of the most important factors due to its combined effect on both chemical and biological processes. In greenhouse experiment, the effect of pH (within the pH range 3.6 - 8.9) on As uptake as well as biomass of Pityrogramma calomelanos was evaluated. The plants were grown in mining soil containing 645.6 mg As kg(-1) for 14 weeks. Within this time, the plant biomass growth was 3.78 - 8.64 g d. wt. per plant and the removal amounted 6.3-18.4 mg As per plant. Translocation factor (ratio of As in fronds to roots) of the fern was 3.6 - 9.7, indicating its potential in phytoremediation of As contaminated soil. Influence of pH on As bioavailability was visible as the available As concentration was higher in acidic soil compared to alkaline soil. Furthermore, it was found that As accumulation by Pityrogramma calomelanos was optimum in the soil of pH 3.6. Nevertheless, the results of this study demonstrate that remediation of As-contaminated mining soils, by this fern, can be improved by changing the soil pH from 4.6 to 6.8.

  17. Formation of biomineral iron oxides compounds in a Fe hyperaccumulator plant: Imperata cylindrica (L.) P. Beauv.

    PubMed

    Fuente, V; Rufo, L; Juárez, B H; Menéndez, N; García-Hernández, M; Salas-Colera, E; Espinosa, A

    2016-01-01

    We report a detailed work of composition and location of naturally formed iron biominerals in plant cells tissues grown in iron rich environments as Imperata cylindrica. This perennial grass grows on the Tinto River banks (Iberian Pyritic Belt) in an extreme acidic ecosystem (pH∼2.3) with high concentration of dissolved iron, sulphate and heavy metals. Iron biominerals were found at the cellular level in tissues of root, stem and leaf both in collected and laboratory-cultivated plants. Iron accumulated in this plant as a mix of iron compounds (mainly as jarosite, ferrihydrite, hematite and spinel phases) was characterized by X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), Mössbauer spectroscopy (MS), magnetometry (SQUID), electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX; TEM-EDX; HRSTEM). A low fraction of phosphorous was detected in this iron hyperaccumulator plant. Root and rhizomes tissues present a high proportion of ferromagnetic iron oxide compounds. Iron oxides-rich zones are localized in electron dense intra and inter-cellular aggregates that appear as dark deposits covering the inner membrane and organelles of the cell. This study aims to contribute to a better understanding of the mechanisms of accumulation, transport, distribution of iron in Imperata cylindrica.

  18. Prosopis laevigata a potential chromium (VI) and cadmium (II) hyperaccumulator desert plant.

    PubMed

    Buendía-González, L; Orozco-Villafuerte, J; Cruz-Sosa, F; Barrera-Díaz, C E; Vernon-Carter, E J

    2010-08-01

    The bioaccumulation of Cr(VI) and Cd(II) in Prosopis laevigata and the effect of these heavy metals on plant growth were assessed. P. laevigata seeds were cultured during 50 days on modified Murashige-Skoog medium supplemented with four different concentrations of Cr(VI) (0-3.4mM) and Cd(II) (0-2.2mM), respectively. Heavy metals did not stop germination, but smaller plants with fewer leaves and secondary roots were produced. Seedlings showed an accumulation of 8176 and 21,437 mg Cd kg(-1) and of 5461 and 8090 mg Cr kg(-1) dry weight, in shoot and root, when cultured with 0.65 mM Cd(II) and 3.4mM Cr(VI), respectively. These results indicated that significant translocation from the roots unto aerial parts took place. A bioaccumulation factor greater than 100 for Cd and 24 for Cr was exhibited by the seedlings. P. laevigata can be considered as a potential hyperaccumulator of Cd(II) and Cr(VI) species and considered as a promising candidate for phytoremediation purposes.

  19. Evaluation of novel starch-deficient mutants of Chlorella sorokiniana for hyper-accumulation of lipids

    PubMed Central

    Vonlanthen, Sofie; Dauvillée, David; Purton, Saul

    2015-01-01

    When green algae are exposed to physiological stresses such as nutrient deprivation, growth is arrested and the cells channel fixed carbon instead into storage compounds, accumulating first starch granules and then lipid bodies containing triacylglycerides. In recent years there has been significant interest in the commercial exploitation of algal lipids as a sustainable source of biodiesel. Since starch and lipid biosynthesis involves the same C3 precursor pool, it has been proposed that mutations blocking starch accumulation should result in increased lipid yields, and indeed several studies have supported this. The fast-growing, thermotolerant alga Chlorella sorokiniana represents an attractive strain for industrial cultivation. We have therefore generated and characterized starch-deficient mutants of C. sorokiniana and determined whether lipid levels are increased in these strains under stress conditions. One mutant (ST68) is shown to lack isoamylase, whilst two others (ST3 and ST12) are defective in starch phosphorylase. However, we find no significant change in the accumulation or profile of fatty acids in these mutants compared to the wild-type, suggesting that a failure to accumulate starch per se is not sufficient for the hyper-accumulation of lipid, and that more subtle regulatory steps underlie the partitioning of carbon to the two storage products. PMID:26865991

  20. Mycorrhizae increase arsenic uptake by the hyperaccumulator Chinese brake fern (Pteris vittata L.).

    PubMed

    Al Agely, Abid; Sylvia, David M; Ma, Lena Q

    2005-01-01

    Chinese brake fern (Pteris vittata L.) is a hyperaccumulator of arsenic (As) that grows naturally on soils in the southern United States. It is reasonable to expect that mycorrhizal symbiosis may be involved in As uptake by this fern. This is because arbuscular mycorrhizal (AM) fungi have a well-documented role in increasing plant phosphorus (P) uptake, P and As have similar chemical properties, and ferns are known to be colonized by AM fungi. We conducted a factorial greenhouse experiment with three levels of As (0, 50, and 100 mg kg(-1)) and P (0, 25, and 50 mg kg(-1)) and with and without Chinese brake fern colonized by a community of AM fungi from an As-contaminated site. We found that the AM fungi not only tolerated As amendment, but their presence increased frond dry mass at the highest As application rate. Furthermore, the AM fungi increased As uptake across a range of P levels, while P uptake was generally increased only when there was no As amendment. These data indicate that AM fungi have an important role in arsenic accumulation by Chinese brake fern. Therefore, to effectively phytoremediate As-contaminated soils, the mycorrhizal status of ferns needs to be taken into account.

  1. Characterization of arsenic-resistant endophytic bacteria from hyperaccumulators Pteris vittata and Pteris multifida.

    PubMed

    Zhu, Ling-Jia; Guan, Dong-Xing; Luo, Jun; Rathinasabapathi, Bala; Ma, Lena Q

    2014-10-01

    We isolated and characterized As-resistant endophytic bacteria (AEB) from two arsenic hyperaccumulators. Their plant growth promoting traits and the relation between As tolerance and transformation were evaluated. A total of 41 and 33 AEB were isolated from Pteris vittata (PV) and Pteris multifida (PM) respectively. PV AEB represented 2genera while PM AEB comprised of 12 genera, with Bacillus sp. being the most dominant bacteria from both plants. All AEB had limited ability in solubilizing P and producing indole acetic acid (IAA) and siderophore. All isolates tolerated 10mM arsenate (As(V)), with PV isolates being more tolerant to As(V) and PM more tolerant to arsenite (As(III)). Bacterial arsenic tolerance was related to their ability in As(III) oxidation and As(V) reduction as well as their ability to retain As in the biomass to a varying extent. Though AEB showed limited plant growth promoting traits, they were important in arsenic tolerance and speciation in plants.

  2. Hormesis phenomena under Cd stress in a hyperaccumulator--Lonicera japonica Thunb.

    PubMed

    Jia, Lian; He, Xingyuan; Chen, Wei; Liu, Zhouli; Huang, Yanqing; Yu, Shuai

    2013-04-01

    A hydroponic experiment was carried out to investigate possible hormetic response induced by cadmium (Cd) in a potential hyperaccumulator-Lonicera japonica Thunb. The results showed that Cd at low concentrations induced a significant increase in plant growth, leaf water content and content of photosynthetic pigments in L. japonica, but decreased them at high concentrations, displayed inverted U-shaped dose response curves, confirming a typical biphasic hormetic response. The U-shaped dose response curves were displayed in malondialdehyde (MDA) and electrolyte leakage in leaves at low doses of Cd, indicating reduce oxidative stress and toxic effect. The increase of superoxide dismutase (SOD) and catalase (CAT) activities was observed along with the increased Cd concentration, indicative of increase in anti-oxidative capacity that ensures redox homeostasis is maintained. After 28 days exposure to 10 mg L(-1) Cd, stem and leaf Cd concentrations reached 502.96 ± 28.90 and 103.22 ± 5.62 mg kg(-1) DW, respectively and the plant had high bioaccumulation coefficient (BC) and translocation factor (TF'). Moreover, the maximum TF value was found at 2.5 mg L(-1) Cd treatment, implying that low Cd treatment improved the ability to transfer Cd from medium via roots to aerial structures. Taking together, L. japonica could be considered as a new plant to investigate the underlying mechanisms of hormesis and Cd tolerance. Our results suggest that hormetic effects should be taken into consideration in phytoremediation of Cd-contaminated soil.

  3. Selenium hyperaccumulator plants Stanleya pinnata and Astragalus bisulcatus are colonized by Se-resistant, Se-excluding wasp and beetle seed herbivores.

    PubMed

    Freeman, John L; Marcus, Matthew A; Fakra, Sirine C; Devonshire, Jean; McGrath, Steve P; Quinn, Colin F; Pilon-Smits, Elizabeth A H

    2012-01-01

    Selenium (Se) hyperaccumulator plants can concentrate the toxic element Se up to 1% of shoot (DW) which is known to protect hyperaccumulator plants from generalist herbivores. There is evidence for Se-resistant insect herbivores capable of feeding upon hyperaccumulators. In this study, resistance to Se was investigated in seed chalcids and seed beetles found consuming seeds inside pods of Se-hyperaccumulator species Astragalus bisulcatus and Stanleya pinnata. Selenium accumulation, localization and speciation were determined in seeds collected from hyperaccumulators in a seleniferous habitat and in seed herbivores. Astragalus bisulcatus seeds were consumed by seed beetle larvae (Acanthoscelides fraterculus Horn, Coleoptera: Bruchidae) and seed chalcid larvae (Bruchophagus mexicanus, Hymenoptera: Eurytomidae). Stanleya pinnata seeds were consumed by an unidentified seed chalcid larva. Micro X-ray absorption near-edge structure (µXANES) and micro-X-Ray Fluorescence mapping (µXRF) demonstrated Se was mostly organic C-Se-C forms in seeds of both hyperaccumulators, and S. pinnata seeds contained ∼24% elemental Se. Liquid chromatography-mass spectrometry of Se-compounds in S. pinnata seeds detected the C-Se-C compound seleno-cystathionine while previous studies of A. bisulcatus seeds detected the C-Se-C compounds methyl-selenocysteine and γ-glutamyl-methyl-selenocysteine. Micro-XRF and µXANES revealed Se ingested from hyperaccumulator seeds redistributed throughout seed herbivore tissues, and portions of seed C-Se-C were biotransformed into selenocysteine, selenocystine, selenodiglutathione, selenate and selenite. Astragalus bisulcatus seeds contained on average 5,750 µg Se g(-1), however adult beetles and adult chalcid wasps emerging from A. bisulcatus seed pods contained 4-6 µg Se g(-1). Stanleya pinnata seeds contained 1,329 µg Se g(-1) on average; however chalcid wasp larvae and adults emerging from S. pinnata seed pods contained 9 and 47 µg Se g(-1). The

  4. Effects of Cu on the content of chlorophylls and secondary metabolites in the Cu-hyperaccumulator lichen Stereocaulon japonicum.

    PubMed

    Nakajima, Hiromitsu; Hara, Kojiro; Yamamoto, Yoshikazu; Itoh, Kiminori

    2015-03-01

    Understanding the relationship between Cu and Cu-hyperaccumulator lichens is important for their application in monitoring and assessing heavy metal pollution. We investigated the Cu-hyperaccumulator lichen Stereocaulon japonicum at several Cu-polluted and control sites in Japan, and found the lichen to be widely distributed. Its concentrations of Cu, chlorophylls, and secondary metabolites, chlorophyll-related indices, and absorption spectra were measured, and we observed negative effects of Cu on these concentrations and indices. For highly Cu-polluted samples (>100ppm dry weight), however, we found significant linear correlations between Cu and chlorophyll concentrations. This can be considered as the response of the photobiont in S. japonicum to Cu stress. In highly Cu-polluted samples the chlorophyll-related indices and concentration of total secondary metabolites were almost constant regardless of Cu concentration. This suggests that the increase in chlorophyll concentration with the increase in Cu concentration enhances photosynthetic productivity per unit biomass, which will allow the production of extra structure and energy for maintaining the chlorophyll-related indices under Cu stress. The relationship between the increase in chlorophyll concentration of S. japonicum and the decrease in secondary metabolite concentration of the lichen can be explained by considering the balance of carbohydrates in the lichen. We found that a spectral index A372-A394 can be a useful index of the concentrations of Cu and total secondary metabolites in S. japonicum. These findings show the adjustment of the content of chlorophylls and secondary metabolites in S. japonicum to Cu stress, and provide a better understanding of the relationship between Cu and the Cu-hyperaccumulator lichen.

  5. In vivo localization of manganese in the hyperaccumulator Gossia bidwillii (Benth.) N. Snow & Guymer (Myrtaceae) by cryo-SEM/EDAX.

    PubMed

    Fernando, Denise R; Batianoff, George N; Baker, Alan J; Woodrow, Ian E

    2006-05-01

    Gossia bidwillii (Myrtaceae) is a manganese (Mn)-hyperaccumulating tree native to subtropical eastern Australia. It typically contains foliar Mn levels in excess of 1% dry weight. However, in G. bidwillii and other Mn-hyperaccumulating species, the cellular and subcellular localization of Mn has not been measured. Quantitative in vivo cryo-scanning electron microscopy (SEM)/energy dispersive X-ray analysis (EDAX) was used to localize Mn and other elements in tissue collected from mature trees growing in a natural population. Cryo-SEM showed that the leaf mesophyll is differentiated as a double-layer palisade mesophyll above spongy mesophyll. Transmission electron microscopy (TEM) revealed that the palisade and epidermal cells are highly vacuolated. EDAX data were used to estimate in situ vacuolar Mn concentrations of all cell types in fresh cryo-fixed leaf tissues. The highest average vacuolar Mn concentration of over 500 mM was found in the upper-layer palisade mesophyll, while the lowest concentration of around 100 mM was found in the spongy mesophyll. Qualitative in vivo cryo-SEM/EDAX was employed to further investigate the spatial distribution of Mn in fresh leaf tissues and young bark tissue, which was also found to have a high Mn concentration. It is concluded that Mn distribution in G. bidwillii is quantitatively different to metal distribution in other hyperaccumulating species where the highest localized concentrations of these elements occur in non-photosynthmetic tissues such as epidermal cells and associated dermal structures including trichomes and leaf hairs.

  6. Chromate and phosphate inhibited each other's uptake and translocation in arsenic hyperaccumulator Pteris vittata L.

    PubMed

    de Oliveira, Letúzia M; Lessl, Jason T; Gress, Julia; Tisarum, Rujira; Guilherme, Luiz R G; Ma, Lena Q

    2015-02-01

    We investigated the effects of chromate (CrVI) and phosphate (P) on their uptake and translocation in As-hyperaccumulator Pteris vittata (PV). Plants were exposed to 1) 0.10 mM CrVI and 0, 0.25, 1.25, or 2.50 mM P or 2) 0.25 mM P and 0, 0.50, 2.5 or 5.0 mM CrVI for 24 h in hydroponics. PV accumulated 2919 mg/kg Cr in the roots at CrVI₀.₁₀, and 5100 and 3500 mg/kg P in the fronds and roots at P₀.₂₅. When co-present, CrVI and P inhibited each other's uptake in PV. Increasing P concentrations reduced Cr root concentrations by 62-82% whereas increasing CrVI concentrations reduced frond P concentrations by 52-59% but increased root P concentrations by 11-15%. Chromate reduced P transport, with more P being accumulated in PV roots. Though CrVI was supplied, 64-78% and 92-93% CrIII were in PV fronds and roots. Based on X-ray diffraction, Cr₂O₃ was detected in the roots confirming CrVI reduction to CrIII by PV. In short, CrVI and P inhibited each other in uptake and translocation by PV, and CrVI reduction to CrIII in PV roots served as its detoxification mechanism. The finding helps to understand the interactions of P and Cr during their uptake in PV.

  7. Functional analysis of the three HMA4 copies of the metal hyperaccumulator Arabidopsis halleri.

    PubMed

    Nouet, Cécile; Charlier, Jean-Benoit; Carnol, Monique; Bosman, Bernard; Farnir, Frédéric; Motte, Patrick; Hanikenne, Marc

    2015-09-01

    In Arabidopsis halleri, the HMA4 gene has an essential function in Zn/Cd hypertolerance and hyperaccumulation by mediating root-to-shoot translocation of metals. Constitutive high expression of AhHMA4 results from a tandem triplication and cis-activation of the promoter of all three copies. The three AhHMA4 copies possess divergent promoter sequences, but highly conserved coding sequences, and display identical expression profiles in the root and shoot vascular system. Here, an AhHMA4::GFP fusion was expressed under the control of each of the three A. halleri HMA4 promoters in a hma2hma4 double mutant of A. thaliana to individually examine the function of each AhHMA4 copy. The protein showed non-polar localization at the plasma membrane of the root pericycle cells of both A. thaliana and A. halleri. The expression of each AhHMA4::GFP copy complemented the severe Zn-deficiency phenotype of the hma2hma4 mutant by restoring root-to-shoot translocation of Zn. However, each copy had a different impact on metal homeostasis in the A. thaliana genetic background: AhHMA4 copies 2 and 3 were more highly expressed and provided higher Zn tolerance in roots and accumulation in shoots than copy 1, and AhHMA4 copy 3 also increased Cd tolerance in roots. These data suggest a certain extent of functional differentiation among the three A. halleri HMA4 copies, stemming from differences in expression levels rather than in expression profile. HMA4 is a key node of the Zn homeostasis network and small changes in expression level can have a major impact on Zn allocation to root or shoot tissues.

  8. Effects of bacteria on cadmium bioaccumulation in the cadmium hyperaccumulator plant Beta vulgaris var. cicla L.

    PubMed

    Chen, Su; Chao, Lei; Sun, Lina; Sun, Tieheng

    2013-01-01

    To investigate the effects of two cadmium-tolerant bacteria, Staphylococcus pasteuri (S. pasteuri X1) and Agrobacterium tumefaciens (A. tumefaciens X2), on cadmium uptake by the cadmium hyperaccumulator plant Beta vulgaris var. cicla L., a pot experiment with artificially contaminated soil was conducted. The results demonstrated that both cadmium-tolerant bacteria enhanced the dry weight of Beta vulgaris var. cicla L. The total dry weights of plants in the control CK20, S. pasteuri X1 and A. tumefaciens X2 treatments were 0.85, 1.13, and 1.38 g/pot, respectively. Compared with the control CK20 findings, the total dry weight of plants was increased by 32.8 and 61.1% after inoculation with S. pasteuri X1 and A. tumefaciens X2, respectively, indicating that A. tumefaciens X2 more strongly promoted the growth of Beta vulgaris var. cicla L. than S. pasteuri X1. In addition, inoculation with S. pasteuri X1 and A. tumefaciens X2 significantly (p < 0.05) promoted cadmium uptake by plants and improved the bioaccumulation of cadmium by the plants from the soil. Moreover, the inoculation of S. pasteuri X1 and A. tumefaciens X2 effectively facilitated the transfer of cadmium in the soil from the Fe-Mn oxide and residual fractions to the soluble plus exchangeable and weakly specially adsorbed fractions in the rhizosphere soils of plants. The bacterial enhancement of cadmium phytoavailability might provide a potential and promising method to increase the efficiency of phytoextraction.

  9. Lewis acid catalysis and Green oxidations: sequential tandem oxidation processes induced by Mn-hyperaccumulating plants.

    PubMed

    Escande, Vincent; Renard, Brice-Loïc; Grison, Claude

    2015-04-01

    Among the phytotechnologies used for the reclamation of degraded mining sites, phytoextraction aims to diminish the concentration of polluting elements in contaminated soils. However, the biomass resulting from the phytoextraction processes (highly enriched in polluting elements) is too often considered as a problematic waste. The manganese-enriched biomass derived from native Mn-hyperaccumulating plants of New Caledonia was presented here as a valuable source of metallic elements of high interest in chemical catalysis. The preparation of the catalyst Eco-Mn1 and reagent Eco-Mn2 derived from Grevillea exul exul and Grevillea exul rubiginosa was investigated. Their unusual polymetallic compositions allowed to explore new reactivity of low oxidative state of manganese-Mn(II) for Eco-Mn1 and Mn(IV) for Eco-Mn2. Eco-Mn1 was used as a Lewis acid to catalyze the acetalization/elimination of aldehydes into enol ethers with high yields; a new green and stereoselective synthesis of (-)-isopulegol via the carbonyl-ene cyclization of (+)-citronellal was also performed with Eco-Mn1. Eco-Mn2 was used as a mild oxidative reagent and controlled the oxidation of aliphatic alcohols into aldehydes with quantitative yields. Oxidative cleavage was interestingly noticed when Eco-Mn2 was used in the presence of a polyol. Eco-Mn2 allowed direct oxidative iodination of ketones without using iodine, which is strongly discouraged by new environmental legislations. Finally, the combination of the properties in the Eco-Mn catalysts and reagents gave them an unprecedented potential to perform sequential tandem oxidation processes through new green syntheses of p-cymene from (-)-isopulegol and (+)-citronellal; and a new green synthesis of functionalized pyridines by in situ oxidation of 1,4-dihydropyridines.

  10. Daclatasvir inhibits hepatitis C virus NS5A motility and hyper-accumulation of phosphoinositides

    PubMed Central

    Chukkapalli, Vineela; Berger, Kristi L.; Kelly, Sean M.; Thomas, Meryl; Deiters, Alexander; Randall, Glenn

    2014-01-01

    Combinations of direct-acting antivirals (DAAs) against the hepatitis C virus (HCV) have the potential to revolutionize the HCV therapeutic regime. An integral component of DAA combination therapies are HCV NS5A inhibitors. It has previously been proposed that NS5A DAAs inhibit two functions of NS5A: RNA replication and virion assembly. In this study, we characterize the impact of a prototype NS5A DAA, daclatasvir (DCV), on HCV replication compartment formation. DCV impaired HCV replicase localization and NS5A motility. In order to characterize the mechanism behind altered HCV replicase localization, we examined the impact of DCV on the interaction of NS5A with its essential cellular cofactor, phosphatidylinositol-4-kinase III α (PI4KA). We observed that DCV does not inhibit PI4KA directly, nor does it impair early events of the NS5A-PI4KA interaction that can occur when NS5A is expressed alone. NS5A functions that are unaffected by DCV include PI4KA binding, as determined by co-immunoprecipitation, and a basal accumulation of the PI4KA product, PI4P. However, DCV impairs late steps in PI4KA activation that requires NS5A expressed in the context of the HCV polyprotein. These NS5A functions include hyper-stimulation of PI4P levels and appropriate replication compartment formation. The data are most consistent with a model wherein DCV inhibits conformational changes in the NS5A protein or protein complex formations that occur in the context of HCV polyprotein expression and stimulate PI4P hyper-accumulation and replication compartment formation. PMID:25546252

  11. Soil pollution assessment and identification of hyperaccumulating plants in chromated copper arsenate (CCA) contaminated sites, Korea.

    PubMed

    Usman, Adel R A; Lee, Sang Soo; Awad, Yasser M; Lim, Kyoung Jae; Yang, Jae E; Ok, Yong Sik

    2012-05-01

    In recent decades, heavy metal contamination in soil adjacent to chromated copper arsenate (CCA) treated wood has received increasing attention. This study was conducted to determine the pollution level (PL) based on the concentrations of Cr, Cu and As in soils and to evaluate the remediative capacity of native plant species grown in the CCA contaminated site, Gangwon Province, Korea. The pollution index (PI), integrated pollution index (IPI), bioaccumulation factors (BAF(shoots) and BAF(roots)) and translocation factor (TF) were determined to ensure soil contamination and phytoremediation availability. The 19 soil samples from 10 locations possibly contaminated with Cr, Cu and As were collected. The concentrations of Cr, Cu and As in the soil samples ranged from 50.56-94.13 mg kg(-1), 27.78-120.83 mg kg(-1), and 0.13-9.43 mg kg(-1), respectively. Generally, the metal concentrations decreased as the distance between the CCA-treated wood structure and sampling point increased. For investigating phytoremediative capacity, the 19 native plant species were also collected in the same area with soil samples. Our results showed that only one plant species of Iris ensata, which presented the highest accumulations of Cr (1120 mg kg(-1)) in its shoot, was identified as a hyperaccumulator. Moreover, the relatively higher values of BAF(shoot) (3.23-22.10) were observed for Typha orientalis, Iris ensata and Scirpus radicans Schk, suggesting that these plant species might be applicable for selective metal extraction from the soils. For phytostabilization, the 15 plant species with BAF(root) values>1 and TF values<1 were suitable; however, Typha orientalis was the best for Cr.

  12. Characterization of a selenium-tolerant rhizosphere strain from a novel Se-hyperaccumulating plant Cardamine hupingshanesis.

    PubMed

    Tong, Xinzhao; Yuan, Linxi; Luo, Lei; Yin, Xuebin

    2014-01-01

    A novel selenium- (Se-) hyperaccumulating plant, Cardamine hupingshanesis, accumulating Se as a form of SeCys2, was discovered in Enshi, Hubei, China, which could not be explained by present selenocysteine methyltransferase (SMT) theory. However, it is interesting to investigate if rhizosphere bacteria play some roles during SeCys2 accumulation. Here, one Se-tolerant rhizosphere strain, Microbacterium oxydans, was isolated from C. hupingshanesis. Phylogenetic analysis and 16S rRNA gene sequences determined the strain as a kind of Gram positive bacillus and belonged to the family Brevibacterium frigoritolerans. Furthermore, Se tolerance test indicated the strain could grow in extreme high Se level of 15.0 mg Se L(-1). When exposed to 1.5 mg Se L(-1), SeCys2 was the predominant Se species in the bacteria, consistent with the Se species in C. hupingshanesis. This coincidence might reveal that this strain played some positive effect in SeCys2 accumulation of C. hupingshanesis. Moreover, when exposed to 1.5 mg Se L(-1) or 15.0 mg Se L(-1), As absorption diminished in the logarithmic phase. In contrast, As absorption increased when exposed to 7.5 mg Se L(-1), indicating As metabolism processes could be affected by Se on this strain. The present study provided a sight on the role of rhizosphere bacteria during Se accumulation for Se-hyperaccumulating plant.

  13. Characterization of arsenate reductase in the extract of roots and fronds of Chinese brake fern, an arsenic hyperaccumulator.

    PubMed

    Duan, Gui-Lan; Zhu, Yong-Guan; Tong, Yi-Ping; Cai, Chao; Kneer, Ralf

    2005-05-01

    Root extracts from the arsenic (As) hyperaccumulating Chinese brake fern (Pteris vittata) were shown to be able to reduce arsenate to arsenite. An arsenate reductase (AR) in the fern showed a reaction mechanism similar to the previously reported Acr2p, an AR from yeast (Saccharomyces cerevisiae), using glutathione as the electron donor. Substrate specificity as well as sensitivity toward inhibitors for the fern AR (phosphate as a competitive inhibitor, arsenite as a noncompetitive inhibitor) was also similar to Acr2p. Kinetic analysis showed that the fern AR had a Michaelis constant value of 2.33 mM for arsenate, 15-fold lower than the purified Acr2p. The AR-specific activity of the fern roots treated with 2 mM arsenate for 9 d was at least 7 times higher than those of roots and shoots of plant species that are known not to tolerate arsenate. A T-DNA knockout mutant of Arabidopsis (Arabidopsis thaliana) with disruption in the putative Acr2 gene had no AR activity. We could not detect AR activity in shoots of the fern. These results indicate that (1) arsenite, the previously reported main storage form of As in the fern fronds, may come mainly from the reduction of arsenate in roots; and (2) AR plays an important role in the detoxification of As in the As hyperaccumulating fern.

  14. Characterization of Arsenate Reductase in the Extract of Roots and Fronds of Chinese Brake Fern, an Arsenic Hyperaccumulator1

    PubMed Central

    Duan, Gui-Lan; Zhu, Yong-Guan; Tong, Yi-Ping; Cai, Chao; Kneer, Ralf

    2005-01-01

    Root extracts from the arsenic (As) hyperaccumulating Chinese brake fern (Pteris vittata) were shown to be able to reduce arsenate to arsenite. An arsenate reductase (AR) in the fern showed a reaction mechanism similar to the previously reported Acr2p, an AR from yeast (Saccharomyces cerevisiae), using glutathione as the electron donor. Substrate specificity as well as sensitivity toward inhibitors for the fern AR (phosphate as a competitive inhibitor, arsenite as a noncompetitive inhibitor) was also similar to Acr2p. Kinetic analysis showed that the fern AR had a Michaelis constant value of 2.33 mm for arsenate, 15-fold lower than the purified Acr2p. The AR-specific activity of the fern roots treated with 2 mm arsenate for 9 d was at least 7 times higher than those of roots and shoots of plant species that are known not to tolerate arsenate. A T-DNA knockout mutant of Arabidopsis (Arabidopsis thaliana) with disruption in the putative Acr2 gene had no AR activity. We could not detect AR activity in shoots of the fern. These results indicate that (1) arsenite, the previously reported main storage form of As in the fern fronds, may come mainly from the reduction of arsenate in roots; and (2) AR plays an important role in the detoxification of As in the As hyperaccumulating fern. PMID:15834011

  15. Interaction of Nickel and Manganese in Accumulation and Localization in Leaves of the Ni Hyperaccumulators Alyssum murale and Alyssum corsicum

    SciTech Connect

    Broadhurst, C.; Tappero, R; Maugel, T; Erbe, E; Sparks, D; Chaney, R

    2009-01-01

    The genus Alyssum contains >50 Ni hyperaccumulator species; many can achieve >2.5% Ni in dry leaf. In soils with normal Mn levels, Alyssum trichome bases were previously observed to accumulate Ni and Mn to high levels. Here we report concentration and localization patterns in A. murale and A. corsicum grown in soils with nonphytotoxic factorial additions of Ni and Mn salts. Four leaf type subsets based on size and age accumulated Ni and Mn similarly. The greatest Mn accumulation (10 times control) was observed in A. corsicum with 40 mmol Mn kg-1 and 40 mmol Ni kg-1 added to potting soil. Whole leaf Ni concentrations decreased as Mn increased. Synchrotron X-ray fluorescence mapping of whole fresh leaves showed localized in distinct high-concentration Mn spots associated with trichomes, Ni and Mn distributions were strongly spatially correlated. Standard X-ray fluorescence point analysis/mapping of cryofractured and freeze-dried samples found that Ni and Mn were co-located and strongly concentrated only in trichome bases and in cells adjacent to trichomes. Nickel concentration was also strongly spatially correlated with sulfur. Results indicate that maximum Ni phytoextraction by Alyssum may be reduced in soils with higher phytoavailable Mn, and suggest that Ni hyperaccumulation in Alyssum species may have developed from a Mn handling system.

  16. Selenium biofortification of broccoli and carrots grown in soil amended with Se-enriched hyperaccumulator Stanleya pinnata.

    PubMed

    Bañuelos, Gary S; Arroyo, Irvin; Pickering, Ingrid J; Yang, Soo In; Freeman, John L

    2015-01-01

    Amending soils with Se-hyperaccumulator plant derived sources of selenium (Se) may be useful for increasing the Se content in food crops in Se-deficient regions of the world. In this study we evaluated total Se and the different chemical species of Se in broccoli and carrots grown in soils amended with ground shoots of the Se-hyperaccumulator Stanleyapinnata. With increasing application rates of S. pinnata, total plant Se concentrations increased to nutritionally ideal levels inside edible parts. Selenium compounds in aqueous extracts were analyzed by SAX-HPLC-ICPMS and identified as a variety of mainly organic-Se forms. Together with bulk Se K-edge X-ray absorption near-edge structure (XANES) analysis performed on broccoli florets, carrot roots and shoots, dried ground S. pinnata, and the amended soil at post-plant, we demonstrate that Se-enriched S. pinnata is valuable as a soil amendment for enriching broccoli and carrots with healthful forms of organic-Se.

  17. Complexation with dissolved organic matter and mobility control of heavy metals in the rhizosphere of hyperaccumulator Sedum alfredii.

    PubMed

    Li, Tingqiang; Tao, Qi; Liang, Chengfeng; Shohag, M J I; Yang, Xiaoe; Sparks, Donald L

    2013-11-01

    The complexation of Zn, Cd and Pb with dissolved organic matter (DOM) in the rhizosphere of hyperaccumulating ecotype (HE) and a non-hyperaccumulating ecotype (NHE) of Sedum alfredii was measured using resin equilibration method. After the growth of HE S. alfredii, the rhizosphere soil pH was reduced by 0.27-0.33 units, due to enhanced DOM derived from root exudation. For both ecotypes of S. alfredii, the fraction of free metal as a percentage of soluble metal varied from 22.1 to 42.5% for Zn(2+), from 8.1 to 15.5% for Cd(2+), and from 4.5 to 10.4% for Pb(2+). Resin equilibration experiment results indicated that HE-DOM had greater ability to form complexes with Zn, Cd and Pb than NHE-DOM, Visual MINTEQ model gave excellent predictions of the complexation of Zn and Cd by DOM (R(2) > 0.97). DOM in the rhizosphere of HE S. alfredii could significantly increase metal mobility through the formation of soluble DOM-metal complexes.

  18. Improved cadmium uptake and accumulation in the hyperaccumulator Sedum alfredii: the impact of citric acid and tartaric acid* #

    PubMed Central

    Lu, Ling-li; Tian, Sheng-ke; Yang, Xiao-e; Peng, Hong-yun; Li, Ting-qiang

    2013-01-01

    The elucidation of a natural strategy for metal hyperaccumulation enables the rational design of technologies for the clean-up of metal-contaminated soils. Organic acid has been suggested to be involved in toxic metallic element tolerance, translocation, and accumulation in plants. The impact of exogenous organic acids on cadmium (Cd) uptake and translocation in the zinc (Zn)/Cd co-hyperaccumulator Sedum alfredii was investigated in the present study. By the addition of organic acids, short-term (2 h) root uptake of 109Cd increased significantly, and higher 109Cd contents in roots and shoots were noted 24 h after uptake, when compared to controls. About 85% of the 109Cd taken up was distributed to the shoots in plants with citric acid (CA) treatments, as compared with 75% within controls. No such effect was observed for tartaric acid (TA). Reduced growth under Cd stress was significantly alleviated by low CA. Long-term application of the two organic acids both resulted in elevated Cd in plants, but the effects varied with exposure time and levels. The results imply that CA may be involved in the processes of Cd uptake, translocation and tolerance in S. alfredii, whereas the impact of TA is mainly on the root uptake of Cd. PMID:23365009

  19. Growth and Metal Accumulation of an Alyssum murale Nickel Hyperaccumulator Ecotype Co-cropped with Alyssum montanum and Perennial Ryegrass in Serpentine Soil.

    PubMed

    Broadhurst, Catherine L; Chaney, Rufus L

    2016-01-01

    The genus Alyssum (Brassicaceae) contains Ni hyperaccumulators (50), many of which can achieve 30 g kg(-1) Ni in dry leaf. Some Alyssum hyperaccumulators are viable candidates for commercial Ni phytoremediation and phytomining technologies. It is not known whether these species secrete organic and/or amino acids into the rhizosphere to solubilize Ni, or can make use of such acids within the soil to facilitate uptake. It has been hypothesized that in fields with mixed plant species, mobilization of metals by phytosiderophores secreted by Graminaceae plants could affect Alyssum Ni, Fe, Cu, and Mn uptake. We co-cropped the Ni hyperaccumulator Alyssum murale, non-hyperaccumulator A. montanum and perennial ryegrass in a natural serpentine soil. All treatments had standard inorganic fertilization required for ryegrass growth and one treatment was compost amended. After 4 months A. murale leaves and stems contained 3600 mg kg(-1) Ni which did not differ significantly with co-cropping. Overall Ni and Mn concentrations were significantly higher in A. murale than in A. montanum or L. perenne. Copper was not accumulated by either Alyssum species, but L. perenne accumulated up to 10 mg kg(-1). A. montanum could not compete with either A. murale or ryegrass, and neither Alyssum species survived in the compost-amended soil. Co-cropping with ryegrass reduced Fe and Mn concentrations in A. murale but not to the extent of either increasing Ni uptake or affecting plant nutrition. The hypothesized Alyssum Ni accumulation in response to phytosiderophores secreted by co-cropped grass did not occur. Our data do not support increased mobilization of Mn by a phytosiderophore mechanism either, but the converse: mobilization of Mn by the Alyssum hyperaccumulator species significantly increased Mn levels in L. perenne. Tilling soil to maximize root penetration, adequate inorganic fertilization and appropriate plant densities are more important for developing efficient phytoremediation and

  20. Growth and Metal Accumulation of an Alyssum murale Nickel Hyperaccumulator Ecotype Co-cropped with Alyssum montanum and Perennial Ryegrass in Serpentine Soil

    PubMed Central

    Broadhurst, Catherine L.; Chaney, Rufus L.

    2016-01-01

    The genus Alyssum (Brassicaceae) contains Ni hyperaccumulators (50), many of which can achieve 30 g kg−1 Ni in dry leaf. Some Alyssum hyperaccumulators are viable candidates for commercial Ni phytoremediation and phytomining technologies. It is not known whether these species secrete organic and/or amino acids into the rhizosphere to solubilize Ni, or can make use of such acids within the soil to facilitate uptake. It has been hypothesized that in fields with mixed plant species, mobilization of metals by phytosiderophores secreted by Graminaceae plants could affect Alyssum Ni, Fe, Cu, and Mn uptake. We co-cropped the Ni hyperaccumulator Alyssum murale, non-hyperaccumulator A. montanum and perennial ryegrass in a natural serpentine soil. All treatments had standard inorganic fertilization required for ryegrass growth and one treatment was compost amended. After 4 months A. murale leaves and stems contained 3600 mg kg−1 Ni which did not differ significantly with co-cropping. Overall Ni and Mn concentrations were significantly higher in A. murale than in A. montanum or L. perenne. Copper was not accumulated by either Alyssum species, but L. perenne accumulated up to 10 mg kg−1. A. montanum could not compete with either A. murale or ryegrass, and neither Alyssum species survived in the compost-amended soil. Co-cropping with ryegrass reduced Fe and Mn concentrations in A. murale but not to the extent of either increasing Ni uptake or affecting plant nutrition. The hypothesized Alyssum Ni accumulation in response to phytosiderophores secreted by co-cropped grass did not occur. Our data do not support increased mobilization of Mn by a phytosiderophore mechanism either, but the converse: mobilization of Mn by the Alyssum hyperaccumulator species significantly increased Mn levels in L. perenne. Tilling soil to maximize root penetration, adequate inorganic fertilization and appropriate plant densities are more important for developing efficient phytoremediation and

  1. Sulfate and chromate increased each other's uptake and translocation in As-hyperaccumulator Pteris vittata.

    PubMed

    de Oliveira, Letúzia M; Gress, Julia; De, Jaysankar; Rathinasabapathi, Bala; Marchi, Giuliano; Chen, Yanshan; Ma, Lena Q

    2016-03-01

    We investigated the effects of chromate (CrVI) and sulfate on their uptake and translocation in As-hyperaccumulator Pteris vittata. Plants were exposed to 1) 0.1 mM CrVI and 0, 0.25, 1.25 or 2.5 mM sulfate or 2) 0.25 mM sulfate and 0, 0.5, 2.5 or 5.0 mM CrVI for 1 d in hydroponics. P. vittata accumulated 26 and 1261 mg kg(-1) Cr in the fronds and roots at CrVI0.1, and 2197 and 1589 mg kg(-1) S in the fronds and roots at S0.25. Increasing sulfate concentrations increased Cr root concentrations by 16-66% and helped CrVI reduction to CrIII whereas increasing CrVI concentrations increased frond sulfate concentrations by 3-27%. Increasing sulfate concentrations enhanced TBARS concentrations in the biomass, indicating oxidative stress caused lipid peroxidation in plant cell membranes. However, addition of 0.25-2.5 mM sulfate alleviated CrVI's toxic effects and decreased TBARS from 23.5 to 9.46-12.3 μmol g(-1) FW. Though CrVI was supplied, 78-96% of CrIII was in the biomass, indicating efficient CrVI reduction to CrIII by P. vittata. The data indicated the amazing ability of P. vittata in Cr uptake at 289 mg kg(-1) h(-1) with little translocation to the fronds. These results indicated that P. vittata had potential in Cr phytoremediation in contaminated sites but further studies are needed to evaluate this potential. The facts that CrVI and sulfate helped each other in uptake by P. vittata suggest that CrVI was not competing with sulfate uptake in P. vittata. However, the mechanisms of how sulfate and CrVI enhance each other's accumulation in P. vittata need further investigation.

  2. Nitrate facilitates cadmium uptake, transport and accumulation in the hyperaccumulator Sedum plumbizincicola.

    PubMed

    Hu, Pengjie; Yin, Yong-Gen; Ishikawa, Satoru; Suzui, Nobuo; Kawachi, Naoki; Fujimaki, Shu; Igura, Masato; Yuan, Cheng; Huang, Jiexue; Li, Zhu; Makino, Tomoyuki; Luo, Yongming; Christie, Peter; Wu, Longhua

    2013-09-01

    The aims of this study are to investigate whether and how the nitrogen form (nitrate (NO3 (-)) versus ammonium (NH4 (+))) influences cadmium (Cd) uptake and translocation and subsequent Cd phytoextraction by the hyperaccumulator species Sedum plumbizincicola. Plants were grown hydroponically with N supplied as either NO3 (-) or NH4 (+). Short-term (36 h) Cd uptake and translocation were determined innovatively and quantitatively using a positron-emitting (107)Cd tracer and positron-emitting tracer imaging system. The results show that the rates of Cd uptake by roots and transport to the shoots in the NO3 (-) treatment were more rapid than in the NH4 (+) treatment. After uptake for 36 h, 5.6 (0.056 μM) and 29.0 % (0.290 μM) of total Cd in the solution was non-absorbable in the NO3 (-) and NH4 (+) treatments, respectively. The local velocity of Cd transport was approximately 1.5-fold higher in roots (3.30 cm h(-1)) and 3.7-fold higher in shoots (10.10 cm h(-1)) of NO3 (-)- than NH4 (+)-fed plants. Autoradiographic analysis of (109)Cd reveals that NO3 (-) nutrition enhanced Cd transportation from the main stem to branches and young leaves. Moreover, NO3 (-) treatment increased Cd, Ca and K concentrations but inhibited Fe and P in the xylem sap. In a 21-day hydroponic culture, shoot biomass and Cd concentration were 1.51 and 2.63 times higher in NO3 (-)- than in NH4 (+)-fed plants. We conclude that compared with NH4 (+), NO3 (-) promoted the major steps in the transport route followed by Cd from solution to shoots in S. plumbizincicola, namely its uptake by roots, xylem loading, root-to-shoot translocation in the xylem and uploading to the leaves. S. plumbizincicola prefers NO3 (-) nutrition to NH4 (+) for Cd phytoextraction.

  3. Elevated CO2 concentration increase the mobility of Cd and Zn in the rhizosphere of hyperaccumulator Sedum alfredii.

    PubMed

    Li, Tingqiang; Tao, Qi; Liang, Chengfeng; Yang, Xiaoe

    2014-05-01

    The effects of elevated CO2 on metal species and mobility in the rhizosphere of hyperaccumulator are not well understood. We report an experiment designed to compare the effects of elevated CO2 on Cd/Zn speciation and mobility in the rhizosphere of hyperaccumulating ecotype (HE) and a non-hyperaccumulating ecotype (NHE) of Sedum alfredii grown under ambient (350 μl l(-1)) or elevated (800 μl l(-1)) CO2 conditions. No difference in solution pH of NHE was observed between ambient and elevated CO2 treatments. For HE, however, elevated CO2 reduced soil solution pH by 0.22 unit, as compared to ambient CO2 conditions. Elevated CO2 increased dissolved organic carbon (DOC) and organic acid levels in soil solution of both ecotypes, but the increase in HE solution was much greater than in NHE solution. After the growth of HE, the concentrations of Cd and Zn in soil solution decreased significantly regardless of CO2 level. The visual MINTEQ speciation model predicted that Cd/Zn-DOM complexes were the dominant species in soil solutions, followed by free Cd(2+) and Zn(2+) species for both ecotypes. However, Cd/Zn-DOM complexes fraction in soil solution of HE was increased by the elevated CO2 treatment (by 8.01 % for Cd and 8.47 % for Zn, respectively). Resin equilibration experiment results indicated that DOM derived from the rhizosphere of HE under elevated CO2 (HE-DOM-E) (90 % for Cd and 73 % for Zn, respectively) showed greater ability to form complexes with Cd and Zn than those under ambient CO2 (HE-DOM-A) (82 % for Cd and 61 % for Zn, respectively) in the undiluted sample. HE-DOM-E showed greater ability to extract Cd and Zn from soil than HE-DOM-A. It was concluded that elevated CO2 could increase the mobility of Cd and Zn due to the enhanced formation of DOM-metal complexes in the rhizosphere of HE S. alfredii.

  4. A hyperaccumulation pathway to three-dimensional hierarchical porous nanocomposites for highly robust high-power electrodes

    NASA Astrophysics Data System (ADS)

    Zhu, Jian; Shan, Yu; Wang, Tao; Sun, Hongtao; Zhao, Zipeng; Mei, Lin; Fan, Zheng; Xu, Zhi; Shakir, Imran; Huang, Yu; Lu, Bingan; Duan, Xiangfeng

    2016-11-01

    Natural plants consist of a hierarchical architecture featuring an intricate network of highly interconnected struts and channels that not only ensure extraordinary structural stability, but also allow efficient transport of nutrients and electrolytes throughout the entire plants. Here we show that a hyperaccumulation effect can allow efficient enrichment of selected metal ions (for example, Sn2+, Mn2+) in the halophytic plants, which can then be converted into three-dimensional carbon/metal oxide (3DC/MOx) nanocomposites with both the composition and structure hierarchy. The nanocomposites retain the 3D hierarchical porous network structure, with ultrafine MOx nanoparticles uniformly distributed in multi-layers of carbon derived from the cell wall, cytomembrane and tonoplast. It can simultaneously ensure efficient electron and ion transport and help withstand the mechanical stress during the repeated electrochemical cycles, enabling the active material to combine high specific capacities typical of batteries and the cycling stability of supercapacitors.

  5. A hyperaccumulation pathway to three-dimensional hierarchical porous nanocomposites for highly robust high-power electrodes

    PubMed Central

    Zhu, Jian; Shan, Yu; Wang, Tao; Sun, Hongtao; Zhao, Zipeng; Mei, Lin; Fan, Zheng; Xu, Zhi; Shakir, Imran; Huang, Yu; Lu, Bingan; Duan, Xiangfeng

    2016-01-01

    Natural plants consist of a hierarchical architecture featuring an intricate network of highly interconnected struts and channels that not only ensure extraordinary structural stability, but also allow efficient transport of nutrients and electrolytes throughout the entire plants. Here we show that a hyperaccumulation effect can allow efficient enrichment of selected metal ions (for example, Sn2+, Mn2+) in the halophytic plants, which can then be converted into three-dimensional carbon/metal oxide (3DC/MOx) nanocomposites with both the composition and structure hierarchy. The nanocomposites retain the 3D hierarchical porous network structure, with ultrafine MOx nanoparticles uniformly distributed in multi-layers of carbon derived from the cell wall, cytomembrane and tonoplast. It can simultaneously ensure efficient electron and ion transport and help withstand the mechanical stress during the repeated electrochemical cycles, enabling the active material to combine high specific capacities typical of batteries and the cycling stability of supercapacitors. PMID:27853174

  6. A significant positive correlation between endogenous trans-zeatin content and total arsenic in arsenic hyperaccumulator Pteris cretica var. nervosa.

    PubMed

    Zhang, Xuemei; Yang, Xiaoyan; Wang, Hongbin; Li, Qinchun; Wang, Haijuan; Li, Yanyan

    2017-04-01

    A pot experiment was conducted to compare the content of endogenous trans-zeatin (Z), plant arsenic (As) uptake and physiological indices in the fronds of As-hyperaccumulator (Pteris cretica var. nervosa) and non-hyperaccumulator (Pteris ensiformis). Furthermore, a stepwise regression method was used to study the relationship among determined indices, and the time-course effect of main indices was also investigated under 100mg/kg As stress with time extension. In the 100-200mg/kg As treatments, plant height showed no significant difference and endogenous Z content significantly increased in P. cretica var. nervosa compared to the control, but a significant decrease of height and endogenous Z was observed in P. ensiformis. The concentrations of As (III) and As (V) increased significantly in the fronds of two plants, but this increase was much higher in P. cretica var. nervosa. Compared to the control, the contents of chlorophyll and soluble protein were significantly increased in P. cretica var. nervosa but decreased in P. ensiformis in the 200mg/kg As treatment, respectively. A significant positive correlation was found between the contents of endogenous Z and total As in P. cretica var. nervosa, but such a correlation was not found in P. ensiformis. Additionally, in the time-course effect experiment, a peak value of each index was appeared in the 43rd day in two plants, except for chlorophyll in P. ensiformis, but this value was significantly higher in P. cretica var. nervosa than that in P. ensiformis. In conclusion, a higher endogenous Z content contributed to As accumulation of P. cretica var. nervosa under As stress.

  7. A proteomics approach to investigate the process of Zn hyperaccumulation in Noccaea caerulescens (J & C. Presl) F.K. Meyer.

    PubMed

    Schneider, Thomas; Persson, Daniel Pergament; Husted, Søren; Schellenberg, Maja; Gehrig, Peter; Lee, Youngsook; Martinoia, Enrico; Schjoerring, Jan K; Meyer, Stefan

    2013-01-01

    Zinc (Zn) is an essential trace element in all living organisms, but is toxic in excess. Several plant species are able to accumulate Zn at extraordinarily high concentrations in the leaf epidermis without showing any toxicity symptoms. However, the molecular mechanisms of this phenomenon are still poorly understood. A state-of-the-art quantitative 2D liquid chromatography/tandem mass spectrometry (2D-LC-MS/MS) proteomics approach was used to investigate the abundance of proteins involved in Zn hyperaccumulation in leaf epidermal and mesophyll tissues of Noccaea caerulescens. Furthermore, the Zn speciation in planta was analyzed by a size-exclusion chromatography/inductively coupled plasma mass spectrometer (SEC-ICP-MS) method, in order to identify the Zn-binding ligands and mechanisms responsible for Zn hyperaccumulation. Epidermal cells have an increased capability to cope with the oxidative stress that results from excess Zn, as indicated by a higher abundance of glutathione S-transferase proteins. A Zn importer of the ZIP family was more abundant in the epidermal tissue than in the mesophyll tissue, but the vacuolar Zn transporter MTP1 was equally distributed. Almost all of the Zn located in the mesophyll was stored as Zn-nicotianamine complexes. In contrast, a much lower proportion of the Zn was found as Zn-nicotianamine complexes in the epidermis. However, these cells have higher concentrations of malate and citrate, and these organic acids are probably responsible for complexation of most epidermal Zn. Here we provide evidence for a cell type-specific adaptation to excess Zn conditions and an increased ability to transport Zn into the epidermal vacuoles.

  8. Elucidating the selenium and arsenic metabolic pathways following exposure to the non-hyperaccumulating Chlorophytum comosum, spider plant.

    PubMed

    Afton, Scott E; Catron, Brittany; Caruso, Joseph A

    2009-01-01

    Although many studies have investigated the metabolism of selenium and arsenic in hyperaccumulating plants for phytoremediation purposes, few have explored non-hyperaccumulating plants as a model for general contaminant exposure to plants. In addition, the result of simultaneous supplementation with selenium and arsenic has not been investigated in plants. In this study, Chlorophytum comosum, commonly known as the spider plant, was used to investigate the metabolism of selenium and arsenic after single and simultaneous supplementation. Size exclusion and ion-pairing reversed phase liquid chromatography were coupled to an inductively coupled plasma mass spectrometer to obtain putative metabolic information of the selenium and arsenic species in C. comosum after a mild aqueous extraction. The chromatographic results depict that selenium and arsenic species were sequestered in the roots and generally conserved upon translocation to the leaves. The data suggest that selenium was directly absorbed by C. comosum roots when supplemented with Se(VI), but a combination of passive and direct absorption occurred when supplemented with Se(IV) due to the partial oxidation of Se(IV) to Se(VI) in the rhizosphere. Higher molecular weight selenium species were more prevalent in the roots of plants supplemented with Se(IV), but in the leaves of plants supplemented with Se(VI) due to an increased translocation rate. When supplemented as As(III), arsenic is proposed to be passively absorbed as As(III) and partially oxidized to As(V) in the plant root. Although total elemental analysis demonstrates a selenium and arsenic antagonism, a compound containing selenium and arsenic was not present in the general aqueous extract of the plant.

  9. Elucidating the selenium and arsenic metabolic pathways following exposure to the non-hyperaccumulating Chlorophytum comosum, spider plant

    PubMed Central

    Afton, Scott E.; Catron, Brittany; Caruso, Joseph A.

    2009-01-01

    Although many studies have investigated the metabolism of selenium and arsenic in hyperaccumulating plants for phytoremediation purposes, few have explored non-hyperaccumulating plants as a model for general contaminant exposure to plants. In addition, the result of simultaneous supplementation with selenium and arsenic has not been investigated in plants. In this study, Chlorophytum comosum, commonly known as the spider plant, was used to investigate the metabolism of selenium and arsenic after single and simultaneous supplementation. Size exclusion and ion-pairing reversed phase liquid chromatography were coupled to an inductively coupled plasma mass spectrometer to obtain putative metabolic information of the selenium and arsenic species in C. comosum after a mild aqueous extraction. The chromatographic results depict that selenium and arsenic species were sequestered in the roots and generally conserved upon translocation to the leaves. The data suggest that selenium was directly absorbed by C. comosum roots when supplemented with SeVI, but a combination of passive and direct absorption occurred when supplemented with SeIV due to the partial oxidation of SeIV to SeVI in the rhizosphere. Higher molecular weight selenium species were more prevalent in the roots of plants supplemented with SeIV, but in the leaves of plants supplemented with SeVI due to an increased translocation rate. When supplemented as AsIII, arsenic is proposed to be passively absorbed as AsIII and partially oxidized to AsV in the plant root. Although total elemental analysis demonstrates a selenium and arsenic antagonism, a compound containing selenium and arsenic was not present in the general aqueous extract of the plant. PMID:19273464

  10. Hyperaccumulator of Pb in native plants growing on Peruvian mine tailings

    NASA Astrophysics Data System (ADS)

    Bech, Jaume; Roca, Nuria; Boluda, Rafael; Tume, Pedro; Duran, Paola; Poma, Wilfredo; Sanchez, Isidoro

    2014-05-01

    samples were taken at four locations (CA1, CA2, CA3, CA4) with different levels of Pb. The Pb soil content (mean ± standard deviation) in mg•kg-1 is as follows: CA1 3992 ± 301; CA2 10128 ± 2247, CA3 14197 ± 895, CA4 16060 ± 810. The non-polluted value around the mine was Pb 124 mg•kg-1. Unusual elevated concentrations of Pb (over 1000 mg kg-1) and TF greater than one were detected in shoots of 6 different plants species (Ageratina sp., Achirodine alata, Cortaderia apalothica, Epilobium denticulatum, Taraxacum officinalis and Trifolium repens). The location CA4 has the maximum content of Pb in the shoots of Ageratina sp. (5045±77 mg•kg-1), C. apalothica (3367±188 mg•kg-1), E. denticulatum (13599±848 mg•kg-1), T. officinalis (2533±47 mg•kg-1) and T. repens (2839±231 mg•kg-1). However, the BF (Bioaccumulation Factor) was smaller than one. Despite the low BF index, the great TFs for Pb indicate that these plant species effectively translocate this metal (i.e., 2.4 for Ageratina sp., 2.3 for C. apalothica, 1.6 for T. repens, 1.5 for A. alata, 1.3 for T. officinalis and 1.2 for E. denticulatum). It seems that the BF is not a reliable index when the metal soil concentration is extremely large. Controlled-environment studies must be performed to definitively confirm the Pb hyperaccumulation character of cited plant species.

  11. Recovering metals from sewage sludge, waste incineration residues and similar substances with hyperaccumulative plants

    NASA Astrophysics Data System (ADS)

    Kisser, Johannes; Gattringer, Heinz; Iordanopoulos-Kisser, Monika

    2015-04-01

    observed in so-called hyperaccumulating metalophytes, which are studied for its suitability to be incorporated in metal recovery processes of elements that diffusely occur in different waste streams. In a systematic series of tests under laboratory conditions the accumulation behaviour for many different elements including rare earth metals of a selection of candidate plants growing on sewage sludge, incineration residues and industrial leftovers was assessed (quantitavely and qualitatively). Growth performance of these plants as well as the most suitable substrate properties were evaluated. The results of this project provided the groundwork for further research and development steps that might bring to practical implementation a technological option with potentially huge benefits: The recovery of valuable metal resources from sewage sludge, incineration ashes and metal rich wastewaters by environmentally friendly and low energy means. Simultaneous decontamination of the input substrates from heavy metals, opening the possibility for these nutrient streams to be redirected to biological regeneration processes (for example use as fertilizers in agriculture) without fear of polluting soils with heavy metal loads. Generation of biomass on contaminated substrates can yield usable energy surplus through incineration during or after processing.

  12. Speciation and localization of Zn in the hyperaccumulator Sedum alfredii by extended X-ray absorption fine structure and micro-X-ray fluorescence.

    PubMed

    Lu, Lingli; Liao, Xingcheng; Labavitch, John; Yang, Xiaoe; Nelson, Erik; Du, Yonghua; Brown, Patrick H; Tian, Shengke

    2014-11-01

    Differences in metal homeostasis among related plant species can give important information of metal hyperaccumulation mechanisms. Speciation and distribution of Zn were investigated in a hyperaccumulating population of Sedum alfredii by using extended X-ray absorption fine structure and micro-synchrotron X-ray fluorescence (μ-XRF), respectively. The hyperaccumulator uses complexation with oxygen donor ligands for Zn storage in leaves and stems, and variations in the Zn speciation was noted in different tissues. The dominant chemical form of Zn in leaves was most probably a complex with malate, the most prevalent organic acid in S. alfredii leaves. In stems, Zn was mainly associated with malate and cell walls, while Zn-citrate and Zn-cell wall complexes dominated in the roots. Two-dimensional μ-XRF images revealed age-dependent differences in Zn localization in S. alfredii stems and leaves. In old leaves of S. alfredii, Zn was high in the midrib, margin regions and the petiole, whereas distribution of Zn was essentially uniform in young leaves. Zinc was preferentially sequestered by cells near vascular bundles in young stems, but was highly localized to vascular bundles and the outer cortex layer of old stems. The results suggest that tissue- and age-dependent variations of Zn speciation and distribution occurred in the hyperaccumulator S. alfredii, with most of the Zn complexed with malate in the leaves, but a shift to cell wall- and citric acid-Zn complexes during transportation and storage in stems and roots. This implies that biotransformation in Zn complexation occurred during transportation and storage processes in the plants of S. alfredii.

  13. Tolerance and hyperaccumulation of a mixture of heavy metals (Cu, Pb, Hg, and Zn) by four aquatic macrophytes.

    PubMed

    Romero-Hernández, Jorge Alberto; Amaya-Chávez, Araceli; Balderas-Hernández, Patricia; Roa-Morales, Gabriela; González-Rivas, Nelly; Balderas-Plata, Miguel Ángel

    2017-03-04

    In the present investigation, four macrophytes, namely Typha latifolia (L.), Lemna minor (L.), Eichhornia crassipes (Mart.) Solms-Laubach, and Myriophyllum aquaticum (Vell.) Verdc, were evaluated for their heavy metal (Cu, Pb, Hg, and Zn) hyperaccumulation potential under laboratory conditions. Tolerance analyses were performed for 7 days of exposure at five different treatments of the metals mixture (Cu(+2), Hg(+2), Pb(+2), and Zn(+2)). The production of chlorophyll and carotenoids was determined at the end of each treatment. L. minor revealed to be sensitive, because it did not survive in all the tested concentrations after 72 hours of exposure. E. crassipes and M. aquaticum displayed the highest tolerance to the metals mixture. For the most tolerant species of aquatic macrophytes, The removal kinetics of E. crassipes and M. aquaticum was carried out, using the following mixture of metals: Cu (0.5 mg/L) and Hg, Pb, and Zn 0.25 mg/L. The obtained results revealed that E. crassipes can remove 99.80% of Cu, 97.88% of Pb, 99.53% of Hg, and 94.37% of Zn. M. aquaticum withdraws 95.2% of Cu, 94.28% of Pb, 99.19% of Hg, and 91.91% of Zn. The obtained results suggest that these two species of macrophytes could be used for the phytoremediation of this mixture of heavy metals from the polluted water bodies.

  14. Development of suitable hydroponics system for phytoremediation of arsenic-contaminated water using an arsenic hyperaccumulator plant Pteris vittata.

    PubMed

    Huang, Yi; Miyauchi, Keisuke; Inoue, Chihiro; Endo, Ginro

    2016-01-01

    In this study, we found that high-performance hydroponics of arsenic hyperaccumulator fern Pteris vittata is possible without any mechanical aeration system, if rhizomes of the ferns are kept over the water surface level. It was also found that very low-nutrition condition is better for root elongation of P. vittata that is an important factor of the arsenic removal from contaminated water. By the non-aeration and low-nutrition hydroponics for four months, roots of P. vittata were elongated more than 500 mm. The results of arsenate phytofiltration experiments showed that arsenic concentrations in water declined from the initial concentrations (50 μg/L, 500 μg/L, and 1000 μg/L) to lower than the detection limit (0.1 μg/L) and about 80% of arsenic removed was accumulated in the fern fronds. The improved hydroponics method for P. vittata developed in this study enables low-cost phytoremediation of arsenic-contaminated water and high-affinity removal of arsenic from water.

  15. Zinc hyperaccumulation substitutes for defense failures beyond salicylate and jasmonate signaling pathways of Alternaria brassicicola attack in Noccaea caerulescens.

    PubMed

    Gallego, Berta; Martos, Soledad; Cabot, Catalina; Barceló, Juan; Poschenrieder, Charlotte

    2017-04-01

    The hypothesis of metal defense as a substitute for a defective biotic stress signaling system in metal hyperaccumulators was tested using the pathosystem Alternaria brassicicola-Noccaea caerulescens under low (2 µM), medium (12 µM) and high (102 µM) Zn supply. Regardless the Zn supply, N. caerulescens responded to fungal attack with the activation of both HMA4 coding for a Zn transporter, and biotic stress signaling pathways. Salicylate, jasmonate, abscisic acid and indoleacetic acid concentrations, as well as biotic stress marker genes (PDF1.2, CHIB, LOX2, PR1 and BGL2) were activated 24 h upon inoculation. Based on the activation of defense genes 24 h after the inoculation an incompatible fungal-plant interaction could be predicted. Nonetheless, in the longer term (7 days) no effective protection against A. brassicicola was achieved in plants exposed to low and medium Zn supply. After 1 week the biotic stress markers were even further increased in these plants, and this compatible interaction was apparently not caused by a failure in the signaling of the fungal attack, but due to the lack of specificity in the type of the activated defense mechanisms. Only plants receiving high Zn exhibited an incompatible fungal interaction. High Zn accumulation in these plants, possibly in cooperation with high glucosinolate concentrations, substituted for the ineffective defense system and the interaction turned into incompatible. In a threshold-type response, these joint effects efficiently hampered fungal spread and, consequently decreased the biotic stress signaling.

  16. The Hyperaccumulator Alyssum murale uses Complexation with Nitrogen and Oxygen Donor Ligands for Ni Transport and Storage

    SciTech Connect

    McNear, Jr., D.; Chanay, R; Sparks, D

    2010-01-01

    The Kotodesh genotype of the nickel (Ni) hyperaccumulator Alyssum murale was examined to determine the compartmentalization and internal speciation of Ni, and other elements, in an effort to ascertain the mechanism used by this plant to tolerate extremely high shoot (stem and leaf) Ni concentrations. Plants were grown either hydroponically or in Ni enriched soils from an area surrounding an historic Ni refinery in Port Colborne, Ontario, Canada. Electron probe micro-analysis (EPMA) and synchrotron based micro X-ray fluorescence ({mu}-SXRF) spectroscopy were used to determine the metal distribution and co-localization and synchrotron X-ray and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopies were used to determine the Ni speciation in plant parts and extracted sap. Nickel is concentrated in the dermal leaf and stem tissues of A. murale bound primarily to malate along with other low molecular weight organic ligands and possibly counter anions (e.g., sulfate). Ni is present in the plant sap and vasculature bound to histidine, malate and other low molecular weight compounds. The data presented herein supports a model in which Ni is transported from the roots to the shoots complexed with histidine and stored within the plant leaf dermal tissues complexed with malate, and other low molecular weight organic acids or counter-ions.

  17. Quantitative elemental localisation in leaves and stems of nickel hyperaccumulating shrub Hybanthusfloribundus subsp. floribundus using micro-PIXE spectroscopy

    NASA Astrophysics Data System (ADS)

    Kachenko, Anthony G.; Singh, Balwant; Bhatia, Naveen P.; Siegele, Rainer

    2008-02-01

    Hybanthusfloribundus (Lindl.) F.Muell. subsp. floribundus is a native Australian nickel (Ni) hyperaccumulating shrub and a promising species for rehabilitation and phytoremediation of Ni tailings. Spatial localisation and quantification of Ni in leaf and stem tissues of H.floribundus subsp. floribundus was studied using micro-proton-induced X-ray emission (micro-PIXE) spectroscopy. Young plants, grown in a potting mix under controlled glasshouse conditions were exposed to Ni concentrations of 0 and 26 mM kg-1 for 20 weeks. Leaf and stem samples were hand-sectioned and freeze-dried prior to micro-PIXE analysis. Elemental distribution maps of leaves revealed Ni concentration of 7800 mg kg-1 dry weight (DW) in whole leaf sections, which was identical to the bulk tissue analysis. Elemental maps showed that Ni was preferentially localised in the adaxial epidermis (10,000 mg kg-1 DW) and reached a maximum of up to 10,000 mg kg-1 DW in the leaf margin. Freeze-dried stem sections from the same plants contained lower Ni than leaf tissues (1800 mg kg-1 versus 7800 mg kg-1 DW, respectively), however did not resolve a clear pattern of compartmentalisation across different anatomical regions. Our results suggest localisation in epidermal cells is an important physiological mechanism involved in Ni accumulation and tolerance in leaves of H.floribundus subsp. floribundus.

  18. Impaired leaf CO2 diffusion mediates Cd-induced inhibition of photosynthesis in the Zn/Cd hyperaccumulator Picris divaricata.

    PubMed

    Tang, Lu; Ying, Rong-Rong; Jiang, Dan; Zeng, Xiao-Wen; Morel, Jean-Louis; Tang, Ye-Tao; Qiu, Rong-Liang

    2013-12-01

    Mechanisms of cadmium (Cd)-induced inhibition of photosynthesis in the Zn/Cd hyperaccumulator Picris divaricata were investigated using photosynthesis limitation analysis. P. divaricata seedlings were grown in nutrient solution containing 0, 5, 10, 25, 50, or 75 μM Cd for 2 weeks. Total limitations to photosynthesis (TL) increased from 0% at 5 μM Cd to 68.8% at 75 μM Cd. CO2 diffusional limitation (DL) made the largest contribution to TL, accounting for 93-98% of TL in the three highest Cd treatments, compared to just 2-7% of TL attributable to biochemical limitation (BL). Microscopic imaging revealed significantly decreased stomatal density and mesophyll thickness in the three highest Cd treatments. Chlorophyll fluorescence parameters related to photosynthetic biochemistry (Fv/Fm, NPQ, ΦPSII, and qP) were not significantly decreased by increased Cd supply. Our results suggest that increased DL in leaves is the main cause of Cd-induced inhibition of photosynthesis in P. divaricata, possibly due to suppressed function of mesophyll and stomata. Analysis of chlorophyll fluorescence showed that Cd supply had little effect on photochemistry parameters, suggesting that the PSII reaction centers are not a main target of Cd inhibition of photosynthesis in P. divaricata.

  19. Arsenic uptake, arsenite efflux and plant growth in hyperaccumulator Pteris vittata: Role of arsenic-resistant bacteria.

    PubMed

    Han, Yong-He; Fu, Jing-Wei; Chen, Yanshan; Rathinasabapathi, Bala; Ma, Lena Q

    2016-02-01

    Bacteria-mediated arsenic (As) transformation and their impacts on As and P uptake and plant growth in As-hyperaccumulator Pteris vittata (PV) were investigated under sterile condition. All As-resistant bacteria (9 endophytic and 6 rhizospheric) were As-reducers except one As-oxidizer. After growing two months in media with 37.5 mg kg(-1) AsV, As concentrations in the fronds and roots were 3655-5389 (89-91% AsIII) and 971-1467 mg kg(-1) (41-73% AsIII), corresponding to 22-52% decrease in the As in the media. Bacterial inoculation enhanced As and P uptake by up to 47 and 69%, and PV growth by 20-74%, which may be related to elevated As and P in plants (r = 0.88-0.97, p < 0.05). Though AsV was supplied, 95% of the As in the bacteria-free media was AsIII, suggesting efficient efflux of AsIII by PV roots (120 µg g(-1) root fw). This was supported by the fact that no AsV was detected in media inoculated with As-reducers while 95% of AsV was detected with As-oxidizer. Our data showed that, under As-stress, PV reduced As toxicity by efficient AsIII efflux into media and AsIII translocation to the fronds, and bacteria benefited PV growth probably via enhanced As and P uptake.

  20. Arsenic-induced plant growth of arsenic-hyperaccumulator Pteris vittata: Impact of arsenic and phosphate rock.

    PubMed

    Han, Yong-He; Yang, Guang-Mei; Fu, Jing-Wei; Guan, Dong-Xing; Chen, Yanshan; Ma, Lena Q

    2016-04-01

    Phosphate rock (PR) has been shown to promote plant growth and arsenic (As) uptake by As-hyperaccumulator Pteris vittata (PV). However, little is known about its behaviors in agricultural soils. In this study, impact of 50 mg kg(-1) As and/or 1.5% PR amendment on plant As accumulation and growth was investigated by growing PV for 90 d in three agricultural soils. While As amendment significantly increased plant As uptake and substantially promoted PV growth, the opposite was observed with PR amendment. Arsenic amendment increased plant frond As from 16.9-265 to 961-6017 mg kg(-1),whereas PR amendment lowered frond As to 10.2-216 mg kg(-1). The As-induced plant growth stimulation was 69-71%. While PR amendment increased plant Ca and P uptake, As amendment showed opposite results. The PV biomass was highly correlated with plant As at r = 0.82, but with weak correlations with plant Ca or P at r < 0.30. This study confirmed that 1) As significantly promoted PV growth, probably independent of Ca or P uptake, 2) PR amendment didn't enhance plant growth or As uptake by PV in agricultural soils with adequate available P, and 3) PV effluxed arsenite (AsIII) growing in agricultural soils.

  1. Arsenic transformation and plant growth promotion characteristics of As-resistant endophytic bacteria from As-hyperaccumulator Pteris vittata.

    PubMed

    Xu, Jia-Yi; Han, Yong-He; Chen, Yanshan; Zhu, Ling-Jia; Ma, Lena Q

    2016-02-01

    The ability of As-resistant endophytic bacteria in As transformation and plant growth promotion was determined. The endophytes were isolated from As-hyperaccumulator Pteris vittata (PV) after growing for 60 d in a soil containing 200 mg kg(-1) arsenate (AsV). They were isolated in presence of 10 mM AsV from PV roots, stems, and leaflets, representing 4 phyla and 17 genera. All endophytes showed at least one plant growth promoting characteristics including IAA synthesis, siderophore production and P solubilization. The root endophytes had higher P solubilization ability than the leaflet (60.0 vs. 18.3 mg L(-1)). In presence of 10 mM AsV, 6 endophytes had greater growth than the control, suggesting As-stimulated growth. Furthermore, root endophytes were more resistant to AsV while the leaflet endophytes were more tolerant to arsenite (AsIII), which corresponded to the dominant As species in PV tissues. Bacterial As resistance was positively correlated to their ability in AsV reduction but not AsIII oxidation. The roles of those endophytes in promoting plant growth and As resistance in P. vittata warrant further investigation.

  2. Effect of fertilizer amendments on phytoremediation of Cd-contaminated soil by a newly discovered hyperaccumulator Solanum nigrum L.

    PubMed

    Wei, Shuhe; Li, Yunmeng; Zhou, Qixing; Srivastava, Mrittunjai; Chiu, Siuwai; Zhan, Jie; Wu, Zhijie; Sun, Tieheng

    2010-04-15

    Phytoremediation is a cost-effective, simple and sustainable beneficiary technique to purify the polluted environment. Solanum nigrum L., a newly found cadmium (Cd) hyperaccumulator, has shown the potential to remediate Cd-contaminated soils. Present study investigated the effects of fertilizer amendments on the Cd uptake by S. nigrum. Chicken manure and urea are usual agricultural fertilizers and more environmental friendly. The results showed that Cd concentrations in shoots of S. nigrum were significantly decreased (p<0.05) by 28.2-34.6%, as compared to that of without the addition of chicken manure, but not the case for urea treatment. However, Cd extraction capacities (microg pot(-1)) in shoot biomass of S. nigrum were significantly increased (p<0.05) due to increased shoot biomass. In addition, available Cd concentration in soil significantly decreased due to addition of chicken manure. Thus, urea might be a better fertilizer for strengthening phytoextraction rate of S. nigrum to Cd, and chicken manure may be a better fertilizer for phytostabilization.

  3. Expression of the ZNT1 Zinc Transporter from the Metal Hyperaccumulator Noccaea caerulescens Confers Enhanced Zinc and Cadmium Tolerance and Accumulation to Arabidopsis thaliana.

    PubMed

    Lin, Ya-Fen; Hassan, Zeshan; Talukdar, Sangita; Schat, Henk; Aarts, Mark G M

    2016-01-01

    Prompt regulation of transition metal transporters is crucial for plant zinc homeostasis. NcZNT1 is one of such transporters, found in the metal hyperaccumulator Brassicaceae species Noccaea caerulescens. It is orthologous to AtZIP4 from Arabidopsis thaliana, an important actor in Zn homeostasis. We examined if the NcZNT1 function contributes to the metal hyperaccumulation of N. caerulescens. NcZNT1 was found to be a plasma-membrane located metal transporter. Constitutive overexpression of NcZNT1 in A. thaliana conferred enhanced tolerance to exposure to excess Zn and Cd supply, as well as increased accumulation of Zn and Cd and induction of the Fe deficiency response, when compared to non-transformed wild-type plants. Promoters of both genes were induced by Zn deficiency in roots and shoots of A. thaliana. In A. thaliana, the AtZIP4 and NcZNT1 promoters were mainly active in cortex, endodermis and pericycle cells under Zn deficient conditions. In N. caerulescens, the promoters were active in the same tissues, though the activity of the NcZNT1 promoter was higher and not limited to Zn deficient conditions. Common cis elements were identified in both promoters by 5' deletion analysis. These correspond to the previously determined Zinc Deficiency Responsive Elements found in A. thaliana to interact with two redundantly acting transcription factors, bZIP19 and bZIP23, controlling the Zn deficiency response. In conclusion, these results suggest that NcZNT1 is an important factor in contributing to Zn and Cd hyperaccumulation in N. caerulescens. Differences in cis- and trans-regulators are likely to account for the differences in expression between A. thaliana and N. caerulescens. The high, constitutive NcZNT1 expression in the stele of N. caerulescens roots implicates its involvement in long distance root-to-shoot metal transport by maintaining a Zn/Cd influx into cells responsible for xylem loading.

  4. Microbial siderophores and root exudates enhanced goethite dissolution and Fe/As uptake by As-hyperaccumulator Pteris vittata.

    PubMed

    Liu, Xue; Fu, Jing-Wei; Da Silva, Evandro; Shi, Xiao-Xia; Cao, Yue; Rathinasabapathi, Bala; Chen, Yanshan; Ma, Lena Q

    2017-04-01

    Arsenic (As) in soils is often adsorbed on Fe-(hydro)oxides surface, rendering them more resistant to dissolution, which is undesirable for phytoremediation of As-contaminated soils. Arsenic hyperaccumulator Pteris vittata prefers to grow in calcareous soils where available Fe and As are low. To elucidate its mechanisms of acquiring Fe and As from insoluble sources in soils, we investigated dissolution of goethite with pre-adsorbed arsenate (AsV; As-goethite) in presence of four organic ligands, including two root exudates (oxalate and phytate, dominant in P. vittata) and two microbial siderophores (PG12-siderophore and desferrioxamine B). Their presence increased As solubilization from As-goethite from 0.03 to 0.27-5.33 mg L(-1) compared to the control. The siderophore/phytate bi-ligand treatment released 7.42 mg L(-1) soluble Fe, which was 1.2-fold that of the sum of siderophore and phytate, showing a synergy in promoting As-goethite dissolution. In the ligand-mineral-plant system, siderophore/phytate was most effective in releasing As and Fe from As-goethite. Moreover, the continuous plant uptake induced more As-goethite dissolution. The continued release of As and Fe significantly enhanced their plant uptake (from 0.01 to 0.43 mg plant(-1) As and 2.7-14.8 mg plant(-1) Fe) and plant growth (from 1.2 to 3.1 g plant(-1) fw) in P. vittata. Since microbial siderophores and root exudates often coexist in soil rhizosphere, their synergy in enhancing dissolution of insoluble As-Fe minerals may play an important role in efficient phytoremediation of As-contaminated soils.

  5. Increased ecological risk due to the hyperaccumulation of As in Pteris cretica during the phytoremediation of an As-contaminated site.

    PubMed

    Jeong, Seulki; Moon, Hee Sun; Nam, Kyoungphile

    2015-03-01

    Ecological risk due to the hyperaccumulation of As in Pteris cretica during phytoremediation was evaluated at an abandoned As-contaminated site. Five receptor groups representing terrestrial invertebrates, avian insectivores, small mammals, herbivores, and omnivores were selected as potentially affected ecological receptors. Soil and food ingestion were considered as major exposure pathways. Phytoremediation was performed with P.cretica only and with both P.cretica and siderophores to enhance plant uptake of As. Ecological hazard index (EHI) values for the small mammal greatly exceeded 1.0 even after three weeks of growth regardless of siderophore application, probably due to its limited home range. For the mammalian herbivore, which mainly consumes plant foliage, the EHI values were greater than 5.73 after seven weeks without siderophore application, but the value increased sharply to 29.3 at seven weeks when siderophores were applied. This increased risk could be attributed to the facilitated translocation of As from roots to stems and leaves in P.cretica. Our results suggest that, when a phytoremediation strategy is considered for metals remediation, its ecological consequences should be taken into account to prevent the spread of hyperaccumulated heavy metals throughout the food chain of ecological receptors. Uncertainties involved in the ecological risk assessment process were also discussed.

  6. Elevated salicylic acid levels conferred by increased expression of ISOCHORISMATE SYNTHASE 1 contribute to hyperaccumulation of SUMO1 conjugates in the Arabidopsis mutant early in short days 4.

    PubMed

    Villajuana-Bonequi, Mitzi; Elrouby, Nabil; Nordström, Karl; Griebel, Thomas; Bachmair, Andreas; Coupland, George

    2014-07-01

    Post-translational modification of proteins by attachment of small ubiquitin-like modifier (SUMO) is essential for plant growth and development. Mutations in the SUMO protease early in short days 4 (ESD4) cause hyperaccumulation of conjugates formed between SUMO and its substrates, and phenotypically are associated with extreme early flowering and impaired growth. We performed a suppressor mutagenesis screen of esd4 and identified a series of mutants called suppressor of esd4 (sed), which delay flowering, enhance growth and reduce hyperaccumulation of SUMO conjugates. Genetic mapping and genome sequencing indicated that one of these mutations (sed111) is in the gene salicylic acid induction-deficient 2 (SID2), which encodes ISOCHORISMATE SYNTHASE I, an enzyme required for biosynthesis of salicylic acid (SA). Analyses showed that compared with wild-type plants, esd4 contains higher levels of SID2 mRNA and about threefold more SA, whereas sed111 contains lower SA levels. Other sed mutants also contain lower SA levels but are not mutant for SID2, although most reduce SID2 mRNA levels. Therefore, higher SA levels contribute to the small size, early flowering and elevated SUMO conjugate levels of esd4. Our results support previous data indicating that SUMO homeostasis influences SA biosynthesis in wild-type plants, and also demonstrate that elevated levels of SA strongly increase the abundance of SUMO conjugates.

  7. Biochar provides a safe and value-added solution for hyperaccumulating plant disposal: A case study of Phytolacca acinosa Roxb. (Phytolaccaceae).

    PubMed

    Wang, Shengsen; Gao, Bin; Li, Yuncong; Ok, Yong Sik; Shen, Chaofeng; Xue, Shengguo

    2017-02-27

    In this work, an innovative approach using biochar technology for hyperaccumulator disposal was developed and evaluated. The heavy metal enriched P. acinosa biomass (PBM) was pyrolyzed to produce biochar (PBC). Both PBM and PBC were characterized with X-ray diffraction (XRD) for crystal phases, scanning electron microscopy (SEM) for surface topography, and analyzed for elemental composition and mobility. The results revealed that whewellite, a dominant crystal form in biomass, was decomposed to calcite after pyrolysis. Elemental analysis indicated that 91-99% total non-volatile elements in the biomass were retained in the biochar. The toxicity characteristic leaching procedure (TCLP) results revealed that 94.6% and 0.15% of total Mn was extracted for biomass and biochar, respectively. This suggests that mobility and bioavailability of Mn in biochar was much lower relative to pristine biomass. Batch sorption experiment showed that excellent removal of aqueous silver, lead, cadmium, and copper ions can be achieved with PBC. Findings from this work indicated that biochar technology can provide a value-added solution for hyperaccumulator disposal.

  8. Effective selenium detoxification in the seed proteins of a hyperaccumulator plant: the analysis of selenium-containing proteins of monkeypot nut (Lecythis minor) seeds.

    PubMed

    Németh, Anikó; Dernovics, Mihály

    2015-01-01

    A shotgun proteomic approach was applied to characterize the selenium (Se)-containing proteins of the selenium hyperaccumulator monkeypot nut (Lecythis minor) seeds. The exceptionally high Se content (>4,000 mg kg(-1)) of the sample enabled a straightforward procedure without the need for multiple preconcentration and fractionation steps. The proteins identified were sulfur-rich seed proteins, namely, 11S globulin (Q84ND2), 2S albumin (B6EU54), 2S sulfur-rich seed storage proteins (P04403 and P0C8Y8) and a 11S globulin-like protein (A0EM48). Database directed search for theoretically selenium-containing peptides was assisted by manual spectra evaluation to achieve around 25% coverage on sulfur analogues. Remarkable detoxification mechanisms on the proteome level were revealed in the form of multiple selenomethionine-methionine substitution and the lack of selenocysteine residues. The degree of selenomethionine substitution could be characterized by an exponential function that implies the inhibition of protein elongation by selenomethionine. Our results contribute to the deeper understanding of selenium detoxification procedures in hyperaccumulator plants.

  9. Rhizobium metallidurans sp. nov., a symbiotic heavy metal resistant bacterium isolated from the Anthyllis vulneraria Zn-hyperaccumulator.

    PubMed

    Grison, Claire M; Jackson, Stephen; Merlot, Sylvain; Dobson, Alan; Grison, Claude

    2015-05-01

    A Gram-stain-negative, aerobic, rod-shaped, non-spore-forming bacterium (ChimEc512(T)) was isolated from 56 host seedlings of the hyperaccumulating Anthyllis vulneraria legume, which was on an old zinc mining site at Les Avinières, Saint-Laurent-Le-Minier, Gard, South of France. On the basis of 16S rRNA gene sequence similarities, strain ChimEc512(T) was shown to belong to the genus Rhizobium and to be most closely related to Rhizobium endophyticum CCGE 2052(T) (98.4%), Rhizobium tibeticum CCBAU 85039(T) (98.1%), Rhizobium grahamii CCGE 502(T) (98.0%) and Rhizobium mesoamericanum CCGE 501(T) (98.0%). The phylogenetic relationships of ChimEc512(T) were confirmed by sequencing and analyses of recA and atpD genes. DNA-DNA relatedness values of strain ChimEc512(T) with R. endophyticum CCGE 2052(T), R. tibeticum CCBAU 85039(T), R. mesoamericanum CCGE 52(T), Rhizobium grahamii CCGE 502(T), Rhizobium etli CCBAU 85039(T) and Rhizobium radiobacter KL09-16-8-2(T) were 27, 22, 16, 18, 19 and 11%, respectively. The DNA G+C content of strain ChimEc512(T) was 58.9 mol%. The major cellular fatty acid was C18 : 1ω7c, characteristic of the genus Rhizobium . The polar lipid profile included phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol and phosphatidylcholine and moderate amounts of aminolipids, phospholipid and sulfoquinovosyl diacylglycerol. Although ChimEc512(T) was able to nodulate A. vulneraria, the nodC and nifH genes were not detected by PCR. The rhizobial strain was tolerant to high concentrations of heavy metals: up to 35 mM Zn and up to 0.5 mM Cd and its growth kinetics was not impacted by Zn. The results of DNA-DNA hybridizations and physiological tests allowed genotypic and phenotypic differentiation of strain ChimEc512(T) from species of the genus Rhizobium with validly published names. Strain ChimEc512(T), therefore, represents a novel species, for which the name Rhizobium metallidurans sp. nov. is proposed, with the type strain

  10. Interaction of As and Sb in the hyperaccumulator Pteris vittata L.: changes in As and Sb speciation by XANES.

    PubMed

    Wan, Xiaoming; Lei, Mei; Chen, Tongbin

    2016-10-01

    Arsenic (As) and antimony (Sb) are chemical analogs that display similar characteristics in the environment. The As hyperaccumulator Pteris vittata L. is a potential As-Sb co-accumulating species. However, when this plant is exposed to different As and Sb speciation, the associated accumulating mechanisms and subsequent assimilation processes of As and Sb remain unclear. A 2-week hydroponic experiment was conducted by exposing P. vittata to single AsIII, AsV, SbIII, and SbV or the co-existence of AsIII and SbIII and AsV and SbV. P. vittata could co-accumulate As and Sb in the pinna (>1000 mg kg(-1)) with high translocation (>1) of As and Sb from the root to the pinna. P. vittata displayed apparent preference to the trivalent speciation of As and Sb than to the pentavalent speciation. Under the single exposure of AsIII or SbIII, the pinna concentration of As and Sb was 84 and 765 % higher than that under the single exposure of AsV or SbV, respectively. Despite the provided As speciation, the main speciation of As in the root was AsV, whereas the main speciation of As in the pinna was AsIII. The Sb in the roots comprised SbV and SbIII when exposed to SbV but was exclusively SbIII when exposed to SbIII. The Sb in the pinna was a mixture of SbV and SbIII regardless of the provided Sb speciation. Compared with the single exposure of As, the co-existence of As and Sb increased the As concentration in the pinna of P. vittata by 50-66 %, accompanied by a significant increase in the AsIII percentage in the root. Compared with the single exposure of Sb, the co-existence of Sb and As also increased the Sb concentration in the pinna by 51-100 %, but no significant change in Sb speciation was found in P. vittata.

  11. Expression of the ZNT1 Zinc Transporter from the Metal Hyperaccumulator Noccaea caerulescens Confers Enhanced Zinc and Cadmium Tolerance and Accumulation to Arabidopsis thaliana

    PubMed Central

    Schat, Henk; Aarts, Mark G. M.

    2016-01-01

    Prompt regulation of transition metal transporters is crucial for plant zinc homeostasis. NcZNT1 is one of such transporters, found in the metal hyperaccumulator Brassicaceae species Noccaea caerulescens. It is orthologous to AtZIP4 from Arabidopsis thaliana, an important actor in Zn homeostasis. We examined if the NcZNT1 function contributes to the metal hyperaccumulation of N. caerulescens. NcZNT1 was found to be a plasma-membrane located metal transporter. Constitutive overexpression of NcZNT1 in A. thaliana conferred enhanced tolerance to exposure to excess Zn and Cd supply, as well as increased accumulation of Zn and Cd and induction of the Fe deficiency response, when compared to non-transformed wild-type plants. Promoters of both genes were induced by Zn deficiency in roots and shoots of A. thaliana. In A. thaliana, the AtZIP4 and NcZNT1 promoters were mainly active in cortex, endodermis and pericycle cells under Zn deficient conditions. In N. caerulescens, the promoters were active in the same tissues, though the activity of the NcZNT1 promoter was higher and not limited to Zn deficient conditions. Common cis elements were identified in both promoters by 5’ deletion analysis. These correspond to the previously determined Zinc Deficiency Responsive Elements found in A. thaliana to interact with two redundantly acting transcription factors, bZIP19 and bZIP23, controlling the Zn deficiency response. In conclusion, these results suggest that NcZNT1 is an important factor in contributing to Zn and Cd hyperaccumulation in N. caerulescens. Differences in cis- and trans-regulators are likely to account for the differences in expression between A. thaliana and N. caerulescens. The high, constitutive NcZNT1 expression in the stele of N. caerulescens roots implicates its involvement in long distance root-to-shoot metal transport by maintaining a Zn/Cd influx into cells responsible for xylem loading. PMID:26930473

  12. The hyperaccumulator Sedum plumbizincicola harbors metal-resistant endophytic bacteria that improve its phytoextraction capacity in multi-metal contaminated soil.

    PubMed

    Ma, Ying; Oliveira, Rui S; Nai, Fengjiao; Rajkumar, Mani; Luo, Yongming; Rocha, Inês; Freitas, Helena

    2015-06-01

    Endophyte-assisted phytoremediation has recently been suggested as a successful approach for ecological restoration of metal contaminated soils, however little information is available on the influence of endophytic bacteria on the phytoextraction capacity of metal hyperaccumulating plants in multi-metal polluted soils. The aims of our study were to isolate and characterize metal-resistant and 1-aminocyclopropane-1-carboxylate (ACC) utilizing endophytic bacteria from tissues of the newly discovered Zn/Cd hyperaccumulator Sedum plumbizincicola and to examine if these endophytic bacterial strains could improve the efficiency of phytoextraction of multi-metal contaminated soils. Among a collection of 42 metal resistant bacterial strains isolated from the tissues of S. plumbizincicola grown on Pb/Zn mine tailings, five plant growth promoting endophytic bacterial strains (PGPE) were selected due to their ability to promote plant growth and to utilize ACC as the sole nitrogen source. The five isolates were identified as Bacillus pumilus E2S2, Bacillus sp. E1S2, Bacillus sp. E4S1, Achromobacter sp. E4L5 and Stenotrophomonas sp. E1L and subsequent testing revealed that they all exhibited traits associated with plant growth promotion, such as production of indole-3-acetic acid and siderophores and solubilization of phosphorus. These five strains showed high resistance to heavy metals (Cd, Zn and Pb) and various antibiotics. Further, inoculation of these ACC utilizing strains significantly increased the concentrations of water extractable Cd and Zn in soil. Moreover, a pot experiment was conducted to elucidate the effects of inoculating metal-resistant ACC utilizing strains on the growth of S. plumbizincicola and its uptake of Cd, Zn and Pb in multi-metal contaminated soils. Out of the five strains, B. pumilus E2S2 significantly increased root (146%) and shoot (17%) length, fresh (37%) and dry biomass (32%) of S. plumbizincicola as well as plant Cd uptake (43%), whereas

  13. Identification and validation of heavy metal and radionuclide hyperaccumulating terrestrial plant species, Quarterly technical progress report, December 20, 1995--March 20, 1995

    SciTech Connect

    Kochian, L.; Brady, D.; Last, M.; Ebbs, S.

    1995-12-01

    Although the period covered by this progress report began on December 20, 1994, which was the date that DOE approved the Interagency Agreement, the agreement was not approved by USDA until January 9, 1995 and the first scientists working on the project were not hired until February 1, 1995. The first goal of the research supported by the Interagency Agreement is to use hydroponic techniques to identify plant species and genotypes with potential for heavy metal hyperaccumulation for planting on a test site at Silverbow Creek and for radionuclide ({sup 90}Sr and {sup 137}Cs) accumulation on a test site at INEL, Idaho, later this year. The second goal of this research is to identify soil amendment procedures that will enhance the bioavailability of heavy metals and radionuclides in the soil without increasing the movement of the contaminants of concern (COC`s) into the groundwater. Our initial research covered in this report focuses on the first goal.

  14. Identification and validation of heavy metal and radionuclide hyperaccumulating terrestrial plant species. Quarterly technical progress report, March 20, 1997--June 19, 1997

    SciTech Connect

    Kochian, L.

    1997-11-01

    This laboratory has been involved in a collaborative project focusing on a range of issues related to the phytoremediation of heavy metal-and radionuclide- contaminated soils. While much of the research has been fundamental in nature, involving physiological and molecular characterizations of the mechanisms of hyperaccumulation in plants, the laboratory is also investigating more practical issues related to phytoremediation. A central issue in this latter research has been the identification of amendments capable of increasing the bioavailability and subsequent phytoextraction of radionuclides. The results described here detail these efforts for uranium and Cs-137. A study was also conducted on a Cs-137 contaminated site at Brookhaven National Laboratory (BNL), which allowed application of the laboratory and greenhouse results to a field setting.

  15. Transcriptional up-regulation of genes involved in photosynthesis of the Zn/Cd hyperaccumulator Sedum alfredii in response to zinc and cadmium.

    PubMed

    Tang, Lu; Yao, Aijun; Ming Yuan; Tang, Yetao; Liu, Jian; Liu, Xi; Qiu, Rongliang

    2016-12-01

    Zinc (Zn) and cadmium (Cd) are two closely related chemical elements with very different biological roles in photosynthesis. Zinc plays unique biochemical functions in photosynthesis. Previous studies suggested that in some Zn/Cd hyperaccumulators, many steps in photosynthesis may be Cd tolerant or even Cd stimulated. Using RNA-seq data, we found not only that Cd and Zn both up-regulated the CA1 gene, which encodes a β class carbonic anhydrase (CA) in chloroplasts, but that a large number of other Zn up-regulated genes in the photosynthetic pathway were also significantly up-regulated by Cd in leaves of the Zn/Cd hyperaccumulator Sedum alfredii. These genes also include chloroplast genes involved in transcription and translation (rps18 and rps14), electron transport and ATP synthesis (atpF and ccsA), Photosystem II (PSBI, PSBM, PSBK, PSBZ/YCF9, PSBO-1, PSBQ, LHCB1.1, LHCB1.4, LHCB2.1, LHCB4.3 and LHCB6) and Photosystem I (PSAE-1, PSAF, PSAH2, LHCA1 and LHCA4). Cadmium and Zn also up-regulated the VAR1 gene, which encodes the ATP-dependent zinc metalloprotease FTSH 5 (a member of the FtsH family), and the DAG gene, which influences chloroplast differentiation and plastid development, and the CP29 gene, which supports RNA processing in chloroplasts and has a potential role in signal-dependent co-regulation of chloroplast genes. Further morphological parameters (dry biomass, cross-sectional thickness, chloroplast size, chlorophyll content) and chlorophyll fluorescence parameters confirmed that leaf photosynthesis of S. alfredii responded to Cd much as it did to Zn, which will contribute to our understanding of the positive effects of Zn and Cd on growth of this plant.

  16. "Towards practical cadmium phytoextraction with Thlaspi caerulescens"

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During 2005-2007, a series of field trials were conducted to investigate the potential of Thlapsi caerulescens ecotypes derived from southern France to phytoextract localized Cd/Zn contamination in Thailand. Soil treatments included pH variation and fertilization level. T. caerulescens ecotypes w...

  17. Characteristics of metal-tolerant plant growth-promoting yeast (Cryptococcus sp. NSE1) and its influence on Cd hyperaccumulator Sedum plumbizincicola.

    PubMed

    Liu, Wuxing; Wang, Beibei; Wang, Qingling; Hou, Jinyu; Wu, Longhua; Wood, Jennifer L; Luo, Yongming; Franks, Ashley E

    2016-09-01

    Plant growth-promoting yeasts are often over looked as a mechanism to improve phytoremediation of heavy metals. In this study, Cryptococcus sp. NSE1, a Cd-tolerant yeast with plant growth capabilities, was isolated from the rhizosphere of the heavy metal hyperaccumulator Sedum plumbizincicola. The yeast exhibited strong tolerance to a range of heavy metals including Cd, Cu, and Zn on plate assays. The adsorption rate Cd, Cu, Zn by NSE1 was 26.1, 13.2, and 25.2 %, respectively. Irregular spines were formed on the surface of NSE1 when grown in MSM medium supplemented with 200 mg L(-1) Cd. NSE1 was capable of utilizing 1-aminocyclopropane-1-carboxylate (ACC) as a sole nitrogen source and was capable of solubilization of inorganic phosphate at rates of 195.2 mg L(-1). Field experiments demonstrated that NSE1 increased phytoremediation by increasing the biomass of Cd hyperaccumulator S. plumbizincicola (46 %, p < 0.05) during phytoremediation. Overall, Cd accumulation by S. plumbizincicola was increased from 19.6 to 31.1 mg m(-2) though no difference in the concentration of Cd in the shoot biomass was observed between NSE1 and control. A Cd accumulation ratio of 38.0 % for NSE1 and 17.2 % for control was observed. The HCl-extractable Cd and CaCl2-extractable Cd concentration in the soil of the NSE1 treatment were reduced by 39.2 and 29.5 %, respectively. Community-level physiology profiling, assessed using Biolog Eco plates, indicated functional changes to the rhizosphere community inoculated with NSE1 by average well color development (AWCD) and measurement of richness (diversity). Values of Shannon-Weiner index, Simpson index, and McIntosh index showed a slight but no significant increases. These results indicate that inoculation of NSE1 could increase the shoot biomass of S. plumbizincicola, enhance the Cd accumulation in S. plumbizincicola, and decrease the available heavy metal content in soils significantly without overall significant changes to the

  18. Transcriptome analysis of the key role of GAT2 gene in the hyper-accumulation of copper in the oyster Crassostrea angulata

    NASA Astrophysics Data System (ADS)

    Shi, Bo; Huang, Zekun; Xiang, Xu; Huang, Miaoqin; Wang, Wen-Xiong; Ke, Caihuan

    2015-12-01

    One paradigm of oysters as the hyper-accumulators of many toxic metals is the inter-individual variation of metals, but the molecular mechanisms remain very elusive. A comprehensive analysis of the transcriptome of Crassostrea angulata was conducted to reveal the relationship between gene expression and differential Cu body burden in oysters. Gene ontology analysis for the differentially expressed genes showed that the neurotransmitter transporter might affect the oyster behavior, which in turn led to difference in Cu accumulation. The ATP-binding cassette transporters superfamily played an important role in the maintenance of cell Cu homeostasis, vitellogenin and apolipophorin transport, and elimination of excess Cu. Gill and mantle Cu concentrations were significantly reduced after silencing the GABA transporter 2 (GAT2) gene, but increased after the injection of GABA receptor antagonists, suggesting that the function of GABA transporter 2 gene was strongly related to Cu accumulation. These findings demonstrated that GABA transporter can control the action of transmitter GABA in the nervous system, thereby affecting the Cu accumulation in the gills and mantles.

  19. Transcriptome analysis of the key role of GAT2 gene in the hyper-accumulation of copper in the oyster Crassostrea angulata

    PubMed Central

    Shi, Bo; Huang, Zekun; Xiang, Xu; Huang, Miaoqin; Wang, Wen-Xiong; Ke, Caihuan

    2015-01-01

    One paradigm of oysters as the hyper-accumulators of many toxic metals is the inter-individual variation of metals, but the molecular mechanisms remain very elusive. A comprehensive analysis of the transcriptome of Crassostrea angulata was conducted to reveal the relationship between gene expression and differential Cu body burden in oysters. Gene ontology analysis for the differentially expressed genes showed that the neurotransmitter transporter might affect the oyster behavior, which in turn led to difference in Cu accumulation. The ATP-binding cassette transporters superfamily played an important role in the maintenance of cell Cu homeostasis, vitellogenin and apolipophorin transport, and elimination of excess Cu. Gill and mantle Cu concentrations were significantly reduced after silencing the GABA transporter 2 (GAT2) gene, but increased after the injection of GABA receptor antagonists, suggesting that the function of GABA transporter 2 gene was strongly related to Cu accumulation. These findings demonstrated that GABA transporter can control the action of transmitter GABA in the nervous system, thereby affecting the Cu accumulation in the gills and mantles. PMID:26648252

  20. Arsenic accumulation pattern in 12 Indian ferns and assessing the potential of Adiantum capillus-veneris, in comparison to Pteris vittata, as arsenic hyperaccumulator.

    PubMed

    Singh, Nandita; Raj, Anshita; Khare, P B; Tripathi, R D; Jamil, Sarah

    2010-12-01

    The present study was undertaken to evaluate the ability of some Indian ferns to accumulate and tolerate arsenic. Twelve species of Indian ferns were exposed to 10 mg L(-1) arsenic as sodium arsenate for 15 days in hydroponic system. Depending on the arsenic uptake in the plant parts--Pteris vittata, Pteris cretica, Adiantum capillus-veneris and Nephrolepis exaltata may be categorised as arsenic accumulator. Further, A. capillus-veneris plants were grown in arsenic contaminated soil (200-600 mg kg(-1)) under green-house condition, to assess its arsenic accumulation and tolerance mechanism, in comparison to known As-hyperaccumulator--P. vittata Linn., growing in the same conditions. The experiment identified A. capillus-veneris having a potential to tolerate arsenic up to 500 mg kg(-1). The plants were analysed for the extent of oxidative stress, as a result of arsenic accumulation. A. capillus-veneris was able to detoxify the arsenic stress through induction of anti-oxidant defence system.

  1. Enhanced Cd extraction of oilseed rape (Brassica napus) by plant growth-promoting bacteria isolated from Cd hyperaccumulator Sedum alfredii Hance.

    PubMed

    Pan, Fengshan; Meng, Qian; Luo, Sha; Shen, Jing; Chen, Bao; Khan, Kiran Yasmin; Japenga, Jan; Ma, Xiaoxiao; Yang, Xiaoe; Feng, Ying

    2017-03-04

    Four plant growth-promoting bacteria (PGPB) were used as study materials, among them two heavy metal-tolerant rhizosphere strains SrN1 (Arthrobacter sp.) and SrN9 (Bacillus altitudinis) were isolated from rhizosphere soil, while two endophytic strains SaN1 (Bacillus megaterium) and SaMR12 (Sphingomonas) were identified from roots of the cadmium (Cd)/zinc (Zn) hyperaccumulator Sedum alfredii Hance. A pot experiment was carried out to investigate the effects of these PGPB on plant growth and Cd accumulation of oilseed rape (Brassica napus) plants grown on aged Cd-spiked soil. The results showed that the four PGPB significantly boosted oilseed rape shoot biomass production, improved soil and plant analyzer development (SPAD) value, enhanced Cd uptake of plant and Cd translocation to the leaves. By fluorescent in situ hybridization (FISH) and green fluorescent protein (GFP), we demonstrated the studied S. alfredii endophytic bacterium SaMR12 were able to colonize successfully in the B. napus roots. However, all four PGPB could increase seed Cd accumulation. Due to its potential to enhance Cd uptake by the plant and to restrict Cd accumulation in the seeds, SaMR12 was selected as the most promising microbial partner of B. napus when setting up a plant-microbe fortified remediation system.

  2. Cadmium sorption characteristics of soil amendments and its relationship with the cadmium uptake by hyperaccumulator and normal plants in amended soils.

    PubMed

    Sun, Yan; Wu, Qi-Tang; Lee, Charles C C; Li, Baoqin; Long, Xinxian

    2014-01-01

    In order to select appropriate amendments for cropping hyperaccumulator or normal plants on contaminated soils and establish the relationship between Cd sorption characteristics of soil amendments and their capacity to reduce Cd uptake by plants, batch sorption experiments with 11 different clay minerals and organic materials and a pot experiment with the same amendments were carried out. The pot experiment was conducted with Sedum alfredii and maize (Zea mays) in a co-cropping system. The results showed that the highest sorption amount was by montmorillonite at 40.82 mg/g, while mica was the lowest at only 1.83 mg/g. There was a significant negative correlation between the n value of Freundlich equation and Cd uptake by plants, and between the logarithm of the stability constant K of the Langmuir equation and plant uptake. Humic acids (HAs) and mushroom manure increased Cd uptake by S. alfredii, but not maize, thus they are suitable as soil amendments for the co-cropping S. alfredii and maize. The stability constant K in these cases was 0.14-0.16 L/mg and n values were 1.51-2.19. The alkaline zeolite and mica had the best fixation abilities and significantly decreased Cd uptake by the both plants, with K > or = 1.49 L/mg and n > or = 3.59.

  3. Analysis and characterization of cultivable heavy metal-resistant bacterial endophytes isolated from Cd-hyperaccumulator Solanum nigrum L. and their potential use for phytoremediation.

    PubMed

    Luo, Sheng-lian; Chen, Liang; Chen, Jue-liang; Xiao, Xiao; Xu, Tao-ying; Wan, Yong; Rao, Chan; Liu, Cheng-bin; Liu, Yu-tang; Lai, Cui; Zeng, Guang-ming

    2011-11-01

    This study investigates the heavy metal-resistant bacterial endophytes of Cd-hyperaccumulator Solanum nigrum L. grown on a mine tailing by using cultivation-dependent technique. Thirty Cd-tolerant bacterial endophytes were isolated from roots, stems, and leaves of S. nigrum L. and classified by amplified ribosomal DNA-restriction analysis into 18 different types. Phylogenetic analysis based on 16S rDNA sequences showed that these isolates belonged to four groups: Actinobacteria (43%), Proteobacteria (23%), Bacteroidetes (27%) and Firmicutes (7%). All the isolates were then characterized for their plant growth promoting traits as well as their resistances to different heavy metals; and the actual plant growth promotion and colonization ability were also assessed. Four isolates were re-introduced into S. nigrum L. under Cd stress and resulted in Cd phytotoxicity decrease, as dry weights of roots increased from 55% to 143% and dry weights of above-ground from 64% to 100% compared to the uninoculated ones. The total Cd accumulation of inoculated plants increased from 66% to 135% (roots) and from 22% to 64% (above-ground) compared to the uninoculated ones. Our research suggests that bacterial endophytes are a most promising resource and may be the excellent candidates of bio-inoculants for enhancing the phytoremediation efficiency.

  4. Bioremediation of Cd-DDT co-contaminated soil using the Cd-hyperaccumulator Sedum alfredii and DDT-degrading microbes.

    PubMed

    Zhu, Zhi-qiang; Yang, Xiao-e; Wang, Kai; Huang, Hua-gang; Zhang, Xincheng; Fang, Hua; Li, Ting-qiang; Alva, A K; He, Zhen-li

    2012-10-15

    The development of an integrated strategy for the remediation of soil co-contaminated by heavy metals and persistent organic pollutants is a major research priority for the decontamination of soil slated for use in agricultural production. The objective of this study was to develop a bioremediation strategy for fields co-contaminated with cadmium (Cd), dichlorodiphenyltrichloroethane (DDT), and its metabolites 1, 1-dichloro-2, 2-bis (4-chlorophenyl) ethylene (DDE) and 1, 1-dichloro-2, 2-bis (4-chlorophenyl) ethane (DDD) (DDT, DDE, and DDD are collectively called DDs) using an identified Cd-hyperaccumulator plant Sedum alfredii (SA) and DDT-degrading microbes (DDT-1). Initially, inoculation with DDT-1 was shown to increase SA root biomass in a pot experiment. When SA was applied together with DDT-1, the levels of Cd and DDs in the co-contaminated soil decreased by 32.1-40.3% and 33.9-37.6%, respectively, in a pot experiment over 18 months compared to 3.25% and 3.76% decreases in soil Cd and DDs, respectively, in unplanted, untreated controls. A subsequent field study (18-month duration) in which the levels of Cd and DDs decreased by 31.1% and 53.6%, respectively, confirmed the beneficial results of this approach. This study demonstrates that the integrated bioremediation strategy is effective for the remediation of Cd-DDs co-contaminated soils.

  5. Stable isotope tracing: a powerful tool for selenium speciation and metabolic studies in non-hyperaccumulator plants (ryegrass Lolium perenne L.).

    PubMed

    Di Tullo, Pamela; Versini, Antoine; Bueno, Maïté; Le Hécho, Isabelle; Thiry, Yves; Biron, Philippe; Castrec-Rouelle, Maryse; Pannier, Florence

    2015-12-01

    Selenium is both essential and toxic for mammals; the range between the two roles is narrow and not only dose-dependent but also related to the chemical species present in foodstuff. Unraveling the metabolism of Se in plants as a function of Se source may thus lead to ways to increase efficiency of fertilization procedures in selenium deficient regions. In this study, stable-isotope tracing was applied for the first time in plants to simultaneously monitor the bio-incorporation of two inorganic Se species commonly used as foodstuff enrichment sources. Occurrence and speciation of Se coming from different Se sources were investigated in root and leaf extracts of ryegrass (Lolium perenne L.), which had been co-exposed to two labeled Se species ((77)SeIV and (82)SeVI). Although the plant absorbed similar amounts of Se when supplied in the form of selenite or selenate, the results evidenced marked differences in speciation and tissues allocation. Selenite was converted into organic forms incorporated mostly into high molecular weight compounds with limited translocation to leaves, whereas selenate was highly mobile being little assimilated into organic forms. Double-spike isotopic tracer methodology makes it possible to compare the metabolism of two species-specific Se sources simultaneously in a single experiment and to analyze Se behavior in not-hyperaccumulator plants, the ICP-MS sensitivity being improved by the use of enriched isotopes.

  6. Cadmium Sorption Characteristics of Soil Amendments and its Relationship with the Cadmium Uptake by Hyperaccumulator and Normal Plants in Amended Soils

    PubMed Central

    Sun, Yan; Wu, Qi-Tang; Lee, Charles C.C.; Li, Baoqin; Long, Xinxian

    2013-01-01

    In order to select appropriate amendments for cropping hyperaccumulator or normal plants on contaminated soils and establish the relationship between Cd sorption characteristics of soil amendments and their capacity to reduce Cd uptake by plants, batch sorption experiments with 11 different clay minerals and organic materials and a pot experiment with the same amendments were carried out. The pot experiment was conducted with Sedum alfredii and maize (Zea mays) in a co-cropping system. The results showed that the highest sorption amount was by montmorillonite at 40.82 mg/g, while mica was the lowest at only 1.83 mg/g. There was a significant negative correlation between the n value of Freundlich equation and Cd uptake by plants, and between the logarithm of the stability constant K of the Langmuir equation and plant uptake. Humic acids (HAs) and mushroom manure increased Cd uptake by S. alfredii, but not maize, thus they are suitable as soil amendments for the co-cropping S. alfredii and maize. The stability constant K in these cases was 0.14–0.16 L/mg and n values were 1.51–2.19. The alkaline zeolite and mica had the best fixation abilities and significantly decreased Cd uptake by the both plants, with K ≥ 1.49 L/mg and n ≥ 3.59. PMID:24912231

  7. Arsenic and phosphate rock impacted the abundance and diversity of bacterial arsenic oxidase and reductase genes in rhizosphere of As-hyperaccumulator Pteris vittata.

    PubMed

    Han, Yong-He; Fu, Jing-Wei; Xiang, Ping; Cao, Yue; Rathinasabapathi, Bala; Chen, Yanshan; Ma, Lena Q

    2017-01-05

    Microbially-mediated arsenic (As) transformation in soils affects As speciation and plant uptake. However, little is known about the impacts of As on bacterial communities and their functional genes in the rhizosphere of As-hyperaccumulator Pteris vittata. In this study, arsenite (AsIII) oxidase genes (aroA-like) and arsenate (AsV) reductase genes (arsC) were amplified from three soils, which were amended with 50mgkg(-1) As and/or 1.5% phosphate rock (PR) and grew P. vittata for 90 d. The aroA-like genes in the rhizosphere were 50 times more abundant than arsC genes, consistent with the dominance of AsV in soils. According to functional gene alignment, most bacteria belonged to α-, β- and γ-Proteobacteria. Moreover, aroA-like genes showed a higher biodiversity than arsC genes based on clone library analysis and could be grouped into nine clusters based on terminal restriction fragment length polymorphism (T-RFLP) analysis. Besides, AsV amendment elevated aroA-like gene diversity, but decreased arsC gene diversity. Redundancy analysis indicated that soil pH, available Ca and P, and AsV concentration were key factors driving diverse compositions in aroA-like gene community. This work identified new opportunities to screen for As-oxidizing and/or -reducing bacteria to aid phytoremediation of As-contaminated soils.

  8. Effect of metal stress on photosynthetic pigments in the Cu-hyperaccumulating lichens Cladonia humilis and Stereocaulon japonicum growing in Cu-polluted sites in Japan.

    PubMed

    Nakajima, Hiromitsu; Yamamoto, Yoshikazu; Yoshitani, Azusa; Itoh, Kiminori

    2013-11-01

    To understand the ecology and physiology of metal-accumulating lichens growing in Cu-polluted sites, we investigated lichens near temple and shrine buildings with Cu roofs in Japan and found that Stereocaulon japonicum Th. Fr. and Cladonia humilis (With.) J. R. Laundon grow in Cu-polluted sites. Metal concentrations in the lichen samples collected at some of these sites were determined by inductively coupled plasma mass spectroscopy (ICP-MS). UV-vis absorption spectra of pigments extracted from the lichen samples were measured, and the pigment concentrations were estimated from the spectral data using equations from the literature. Secondary metabolites extracted from the lichen samples were analyzed by high-performance liquid chromatography (HPLC) with a photodiode array detector. We found that S. japonicum and C. humilis are Cu-hyperaccumulating lichens. Differences in pigment concentrations and their absorption spectra were observed between the Cu-polluted and control samples of the 2 lichens. However, no correlation was found between Cu and pigment concentrations. We observed a positive correlation between Al and Fe concentrations and unexpectedly found high negative correlations between Al and pigment concentrations. This suggests that Al stress reduces pigment concentrations. The concentrations of secondary metabolites in C. humilis growing in the Cu-polluted sites agreed with those in C. humilis growing in the control sites. This indicates that the metabolite concentrations are independent of Cu stress.

  9. Effect of CO, NOx and SO2 on ROS production, photosynthesis and ascorbate-glutathione pathway to induce Fragaria×annasa as a hyperaccumulator.

    PubMed

    Muneer, Sowbiya; Kim, Tae Hwan; Choi, Byung Chul; Lee, Beom Seon; Lee, Jeong Hyun

    2014-01-01

    A study was conducted to determine the effect of carbon monoxide (CO), nitroxide (NOx) and sulfur dioxide (SO2) on ROS production, photosynthesis and ascorbate-glutathione pathway in strawberry plants. The results showed that both singlet oxygen (O2(-1)) and hydrogen peroxide (H2O2) content increased in CO, NOx and SO2 treated strawberry leaves. A drastic reduction of primary metabolism of plants (photosynthesis), with the closure of stomata, resulted in a reduction of protein, carbohydrate and sucrose content due to production of reactive oxygen species (ROS) under prolonged exposure of gas stress. The resulting antioxidant enzymes were increased under a low dose of gas stress, whereas they were decreased due to a high dose of gas stress. Our results indicate that increased ROS may act as a signal to induce defense responses to CO, NOx and SO2 gas stress. The increased level of antioxidant enzymes plays a significant role in plant protection due to which strawberry plants can be used as a hyperaccumulator to maintain environmental pollution, however, the defense capacity cannot sufficiently alleviate oxidative damage under prolonged exposure of CO, NOx and SO2 stress.

  10. Improved plant growth and Zn accumulation in grains of rice (Oryza sativa L.) by inoculation of endophytic microbes isolated from a Zn Hyperaccumulator, Sedum alfredii H.

    PubMed

    Wang, Yuyan; Yang, Xiaoe; Zhang, Xincheng; Dong, Lanxue; Zhang, Jie; Wei, Yanyan; Feng, Ying; Lu, Lingli

    2014-02-26

    This study is to investigate the possibility of zinc (Zn) biofortification in the grains of rice (Oryza sativa L.) by inoculation of endophytic strains isolated from a Zn hyperaccumulator, Sedum alfredii Hance. Five endophytic strains, Burkholderia sp. SaZR4, Burkholderia sp. SaMR10, Sphingomonas sp. SaMR12, Variovorax sp. SaNR1, and Enterobacter sp. SaCS20, isolated from S. alfredii, were inoculated in the roots of Japonica rice Nipponbare under hydroponic condition. Fluorescence images showed that endophytic strains successfully colonized rice roots after 72 h. Improved root morphology and plant growth of rice was observed after inoculation with endophytic strains especially SaMR12 and SaCS20. Under hydroponic conditions, endophytic inoculation with SaMR12 and SaCS20 increased Zn concentration by 44.4% and 51.1% in shoots, and by 73.6% and 83.4% in roots, respectively. Under soil conditions, endophytic inoculation with SaMR12 and SaCS20 resulted in an increase of grain yields and elevated Zn concentrations by 20.3% and 21.9% in brown rice and by 13.7% and 11.2% in polished rice, respectively. After inoculation of SaMR12 and SaCS20, rhizosphere soils of rice plants contained higher concentration of DTPA-Zn by 10.4% and 20.6%, respectively. In situ micro-X-ray fluorescence mapping of Zn confirmed the elevated Zn content in the rhizosphere zone of rice treated with SaMR12 as compared with the control. The above results suggested that endophytic microbes isolated from S. alfredii could successfully colonize rice roots, resulting in improved root morphology and plant growth, increased Zn bioavailability in rhizosphere soils, and elevated grain yields and Zn densities in grains.

  11. Aluminium Uptake and Translocation in Al Hyperaccumulator Rumex obtusifolius Is Affected by Low-Molecular-Weight Organic Acids Content and Soil pH

    PubMed Central

    Vondráčková, Stanislava; Száková, Jiřina; Drábek, Ondřej; Tejnecký, Václav; Hejcman, Michal; Müllerová, Vladimíra; Tlustoš, Pavel

    2015-01-01

    Background and Aims High Al resistance of Rumex obtusifolius together with its ability to accumulate Al has never been studied in weakly acidic conditions (pH > 5.8) and is not sufficiently described in real soil conditions. The potential elucidation of the role of organic acids in plant can explain the Al tolerance mechanism. Methods We established a pot experiment with R. obtusifolius planted in slightly acidic and alkaline soils. For the manipulation of Al availability, both soils were untreated and treated by lime and superphosphate. We determined mobile Al concentrations in soils and concentrations of Al and organic acids in organs. Results Al availability correlated positively to the extraction of organic acids (citric acid < oxalic acid) in soils. Monovalent Al cations were the most abundant mobile Al forms with positive charge in soils. Liming and superphosphate application were ambiguous measures for changing Al mobility in soils. Elevated transport of total Al from belowground organs into leaves was recorded in both lime-treated soils and in superphosphate-treated alkaline soil as a result of sufficient amount of Ca available from soil solution as well as from superphosphate that can probably modify distribution of total Al in R. obtusifolius as a representative of “oxalate plants.” The highest concentrations of Al and organic acids were recorded in the leaves, followed by the stem and belowground organ infusions. Conclusions In alkaline soil, R. obtusifolius is an Al-hyperaccumulator with the highest concentrations of oxalate in leaves, of malate in stems, and of citrate in belowground organs. These organic acids form strong complexes with Al that can play a key role in internal Al tolerance but the used methods did not allow us to distinguish the proportion of total Al-organic complexes to the free organic acids. PMID:25880431

  12. Effect of copper stress on cup lichens Cladonia humilis and C. subconistea growing on copper-hyperaccumulating moss Scopelophila cataractae at copper-polluted sites in Japan.

    PubMed

    Nakajima, Hiromitsu; Fujimoto, Kenjiro; Yoshitani, Azusa; Yamamoto, Yoshikazu; Sakurai, Haruka; Itoh, Kiminori

    2012-10-01

    We investigated lichen species in the habitats of the copper (Cu)-hyperaccumulating moss Scopelophila cataractae and found that the cup lichens Cladonia subconistea and C. humilis grow on this moss. We performed X-ray fluorescence and inductively coupled plasma mass (ICP-MS) analysis of lichen samples and measured the visible absorption spectra of the pigments extracted from the samples to assess the effect of Cu stress on the cup lichens. The chlorophyll a/b ratio and degradation of chlorophyll a to pheophytin a were calculated from the spectral data. X-ray fluorescence analysis indicated that Cu concentrations in cup lichens growing on S. cataractae were much higher than those in control samples growing on non-polluted soil. Moreover, Cu microanalysis showed that Cu concentrations in parts of podetia of C. subconistea growing on S. cataractae increased as the substrate (S. cataractae) was approached, whereas those of C. humilis growing on S. cataractae decreased as the substrate was approached. This reflects the difference in the route of Cu ions from the source to the podetia. Furthermore, ICP-MS analysis confirmed that C. subconistea growing on S. cataractae was heavily contaminated with Cu, indicating that this lichen is Cu tolerant. We found a significant difference between the visible absorption spectra of pigments extracted from the Cu-contaminated and control samples. Hence, the spectra could be used to determine whether a cup lichen is contaminated with Cu. Chlorophyll analysis showed that cup lichens growing on S. cataractae were affected by Cu stress. However, it also suggested that the areas of dead moss under cup lichens were a suitable substrate for the growth of the lichen. Moreover, it suggested that cup lichens had allolepathic effects on S. cataractae; it is likely that secondary metabolites produced by cup lichens inhibited moss growth.

  13. Unveiling Zn hyperaccumulation in Juncus acutus: implications on the electronic energy fluxes and on oxidative stress with emphasis on non-functional Zn-chlorophylls.

    PubMed

    Santos, D; Duarte, B; Caçador, I

    2014-11-01

    Juncus acutus arises as possible hyperaccumulator specie, tolerating exogenous Zn concentrations as high as 60 mM. Zinc concentrations here detected in seedlings germinated in the presence high Zn concentrations, were above the described upper toxic levels for higher plants. Even at the highest Zn concentration, growth inhibition only accounted to approximately 30% of control seedlings biomass, presenting an EC₅₀ value in the range of 10-20 mM of metal. PSII quantum yields showed a marked decline, reflection of changes in the thylakoid structure on the PSII electron donor sites. In fact, the electron transport rate was severely affected by Zn in seedlings exposed to higher Zn concentrations leading to a decrease in their maximum electronic transport rate and consequently presenting lower light saturation and lower photosynthetic efficiencies. Although light absorption capacity was not affected by Zn exposure and uptake, energy trapping flux in the photosynthetic apparatus and transport throughout the electronic chain was severely impaired. This lack of efficiency is related with non-functional Zn-chlorophylls formation. There was a strong linear correlation between exogenous Zn concentration applied and the concentration actually verified in the seedlings tissue with the concentration of both ZnChl a and b. There was also a gradual loss of connectivity between the antennae of the PSII units being this more evident at the higher Zn concentrations and thus impairing the energetic transport. The reduction in light harvesting efficiency, leads inevitably to the accumulation of redox energy inside the cells. To counteract ROS generation, all anti-oxidant enzymatic activities (except catalase) showed a proportional response to exogenous and in vivo Zn concentrations. Not only this plant appears to be highly tolerant to high Zn concentrations, but also it can overcome efficiently the damage produced during this uptake by efficiently dissipating the excessive cellular

  14. Cadmium uptake and translocation in tumbleweed (Salsola kali), a potential Cd-hyperaccumulator desert plant species: ICP/OES and XAS studies.

    PubMed

    de la Rosa, Guadalupe; Peralta-Videa, Jose R; Montes, Milka; Parsons, Jason G; Cano-Aguilera, Irene; Gardea-Torresdey, Jorge L

    2004-06-01

    Cadmium is a heavy metal, which, even at low concentrations, can be highly toxic to the growth and development of both plants and animals. Plant species vary extensively in their tolerance to excess cadmium in a growth medium and very few cadmium-tolerant species have been identified. In this study, tumbleweed plants (Salsola kali) grown in an agar-based medium with 20 mgl(-1) of Cd(II) did not show phytotoxicity, and their roots had the most biomass (4.5 mg) (P < 0.05) compared to the control plants (2.7 mg) as well as other treated plants. These plants accumulated 2696, 2075, and 2016 mg Cd kg(-1) of dry roots, stems, and leaves, respectively. The results suggest that there is no restricted cadmium movement in tumbleweed plants. In addition, the amount of Cd found in the dry leaf tissue suggests that tumbleweed could be considered as potential cadmium hyperaccumulating species. X-ray absorption spectroscopy studies demonstrated that in roots, cadmium was bound to oxygen while in stems and leaves, the metal was attached to oxygen and sulfur groups. This might imply that some small organic acids are responsible for Cd transport from roots to stems and leaves. In addition, it might be possible that the plant synthesizes phytochelatins in the stems, later coordinating the absorbed cadmium for transport and storage in cell structures. Thus, it is possible that in the leaves, Cd either exists as a Cd-phytochelatin complex or bound to cell wall structures. Current studies are being performed in order to elucidate the proposed hypothesis.

  15. Characterization of Mn-resistant endophytic bacteria from Mn-hyperaccumulator Phytolacca americana and their impact on Mn accumulation of hybrid penisetum.

    PubMed

    Zhang, Wen-Hui; Chen, Wei; He, Lin-Yan; Wang, Qi; Sheng, Xia-Fang

    2015-10-01

    Three hundred Mn-resistant endophytic bacteria were isolated from the Mn-hyperaccumulator, Phytolacca americana, grown at different levels of Mn (0, 1, and 10mM) stress. Under no Mn stress, 90%, 92%, and 11% of the bacteria produced indole acetic acid (IAA), siderophore, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase, respectively. Under Mn stress, 68-94%, 91-92%, and 21-81% of the bacteria produced IAA, siderophore, and ACC deaminase, respectively. Greater percentages of ACC deaminase-producing bacteria were found in the Mn-treated P. americana. Furthermore, the ratios of IAA- and siderophore-producing bacteria were significantly higher in the Mn treated plant leaves, while the ratio of ACC deaminase-producing bacteria was significantly higher in the Mn treated-roots. Based on 16S rRNA gene sequence analysis, Mn-resistant bacteria were affiliated with 10 genera. In experiments involving hybrid penisetum grown in soils treated with 0 and 1000mgkg(-1) of Mn, inoculation with strain 1Y31 was found to increase the root (ranging from 6.4% to 18.3%) and above-ground tissue (ranging from 19.3% to 70.2%) mass and total Mn uptake of above-ground tissues (64%) compared to the control. Furthermore, inoculation with strain 1Y31 was found to increase the ratio of IAA-producing bacteria in the rhizosphere and bulk soils of hybrid penisetum grown in Mn-added soils. The results showed the effect of Mn stress on the ratio of the plant growth-promoting factor-producing endophytic bacteria of P. americana and highlighted the potential of endophytic bacterium as an inoculum for enhanced phytoremediation of Mn-polluted soils by hybrid penisetum plants.

  16. Elemental selenium particles at nano-size (Nano-Se) are more toxic to Medaka (Oryzias latipes) as a consequence of hyper-accumulation of selenium: a comparison with sodium selenite.

    PubMed

    Li, Hongcheng; Zhang, Jinsong; Wang, Thanh; Luo, Wenru; Zhou, Qunfang; Jiang, Guibin

    2008-09-29

    Recent studies have shown that elemental selenium particles at nano-size (Nano-Se) exhibited comparable bioavailability and less toxicity in mice and rats when compared to sodium selenite, selenomethinine and methylselenocysteine. However, little is known about the toxicity profile of Nano-Se in aquatic animals. In the present study, toxicities of Nano-Se and selenite in selenium-sufficient Medaka fish were compared. Selenium bioaccumulation and subsequent clearance in fish livers, gills, muscles and whole bodies were examined after 10 days of exposure to Nano-Se and selenite (100 microg Se/L) and again after 7 days of depuration. Both forms of selenium exposure effectively increased selenium concentrations in the investigated tissues. Surprisingly, Nano-Se was found to be more hyper-accumulated in the liver compared to selenite with differences as high as sixfold. Selenium clearance of both Nano-Se and selenite occurred at similar ratios in whole bodies and muscles but was not rapidly cleared from livers and gills. Nano-Se exhibited strong toxicity for Medaka with an approximately fivefold difference in terms of LC(50) compared to selenite. Nano-Se also caused larger effects on oxidative stress, most likely due to more hyper-accumulation of selenium in liver. The present study suggests that toxicity of nanoparticles can largely vary between different species and concludes that the evaluation of nanotoxicology should be carried out on a case-by-case basis.

  17. Selective uptake, distribution, and redistribution of (109)Cd, (57)Co, (65)Zn, (63)Ni, and (134)Cs via xylem and phloem in the heavy metal hyperaccumulator Solanum nigrum L.

    PubMed

    Wei, Shuhe; Anders, Iwona; Feller, Urs

    2014-06-01

    The focus of this article was to explore the translocation of (109)Cd, (57)Co, (65)Zn, (63)Ni, and (134)Cs via xylem and phloem in the newly found hyperaccumulator Solanum nigrum L. Two experiments with the uptake via the roots and transport of (109)Cd, (57)Co, and (65)Zn labeled by roots, and the redistribution of (109)Cd, (65)Zn, (57)Co, (63)Ni, and (134)Cs using flap label in S. nigrum in a hydroponic culture with a standard nutrient solution were conducted. The results showed that (109)Cd added for 24 h to the nutrient medium of young plants was rapidly taken up, transferred to the shoot, and accumulated in the cotyledons and the oldest leaves but was not efficiently redistributed within the shoot afterward leading to a rather low content in the fruits. In contrast, (57)Co was more slowly taken up and released to the shoot, but afterward, this element was redistributed from older leaves to younger leaves and maturing fruits. (65)Zn was rapidly taken up and transferred to the shoot (mainly to the youngest leaves and not to the cotyledons). Afterward, this radionuclide was redistributed within the shoot to the youngest organs and finally accumulated in the maturing fruits. After flap labeling, all five heavy metals tested ((109)Cd, (57)Co, (65)Zn, (63)Ni, (134)Cs) were exported from the labeled leaf and redistributed within the plant. The accumulation in the fruits was most pronounced for (63)Ni and (65)Zn, while a relatively high percentage of (57)Co was finally found in the roots. (134)Cs was roughly in the middle of them. The transport of (109)Cd differed from that previously reported for wheat or lupin and might be important for the potential of S. nigrum to hyperaccumulate cadmium.

  18. Inoculation with endophytic Bacillus megaterium 1Y31 increases Mn accumulation and induces the growth and energy metabolism-related differentially-expressed proteome in Mn hyperaccumulator hybrid pennisetum.

    PubMed

    Zhang, Wen-hui; He, Lin-yan; Wang, Qi; Sheng, Xia-Fang

    2015-12-30

    In this study, a hydroponic culture experiment was conducted in a greenhouse to investigate the molecular and microbial mechanisms involved in the endophytic Bacillus megaterium 1Y31-enhanced Mn tolerance and accumulation in Mn hyperaccumulator hybrid pennisetum. Strain 1Y31 significantly increased the dry weights (ranging from 28% to 94%) and total Mn uptake (ranging from 23% to 112%) of hybrid pennisetum treated with 0, 2, and 10mM Mn compared to the control. Total 98 leaf differentially expressed proteins were identified between the live and dead bacterial inoculated hybrid pennisetum. The major leaf differentially expressed proteins were involved in energy generation, photosynthesis, response to stimulus, metabolisms, and unknown function. Furthermore, most of the energy generation and photosynthesis-related proteins were up-regulated, whereas most of the response to stimulus and metabolism-related proteins were down-regulated under Mn stress. Notably, the proportion of indole-3-acetic acid (IAA)-producing endophytic bacteria was significantly higher in the bacterial inoculated plants under Mn stress. The results suggested that strain 1Y31 increased the growth and Mn uptake of hybrid pennisetum through increasing the efficiency of photosynthesis and energy metabolism as well as the proportion of plant growth-promoting endophytic bacteria in the plants.

  19. Amino Acid Features of P1B-ATPase Heavy Metal Transporters Enabling Small Numbers of Organisms to Cope with Heavy Metal Pollution

    PubMed Central

    Ashrafi, E.; Alemzadeh, A.; Ebrahimi, M.; Ebrahimie, E.; Dadkhodaei, N.; Ebrahimi, M.

    2011-01-01

    Phytoremediation refers to the use of plants for extraction and detoxification of pollutants, providing a new and powerful weapon against a polluted environment. In some plants, such as Thlaspi spp, heavy metal ATPases are involved in overall metal ion homeostasis and hyperaccumulation. P1B-ATPases pump a wide range of cations, especially heavy metals, across membranes against their electrochemical gradients. Determination of the protein characteristics of P1B-ATPases in hyperaccumulator plants provides a new opportuntity for engineering of phytoremediating plants. In this study, using diverse weighting and modeling approaches, 2644 protein characteristics of primary, secondary, and tertiary structures of P1B-ATPases in hyperaccumulator and nonhyperaccumulator plants were extracted and compared to identify differences between proteins in hyperaccumulator and nonhyperaccumulator pumps. Although the protein characteristics were variable in their weighting, tree and rule induction models; glycine count, frequency of glutamine-valine, and valine-phenylalanine count were the most important attributes highlighted by 10, five, and four models, respectively. In addition, a precise model was built to discriminate P1B-ATPases in different organisms based on their structural protein features. Moreover, reliable models for prediction of the hyperaccumulating activity of unknown P1B-ATPase pumps were developed. Uncovering important structural features of hyperaccumulator pumps in this study has provided the knowledge required for future modification and engineering of these pumps by techniques such as site-directed mutagenesis. PMID:21573033

  20. Identification and validation of heavy metal and radionuclide accumulating terrestrial plant species. Quarterly technical progress report, June 21, 1995--September 20, 1995

    SciTech Connect

    Kochian, L.

    1995-12-31

    This quarterly report describes experiments on uptake of a variety of heavy metals by plants. Titles of report sections are (1) Alleviation of heavy-metal induced micronutrient deficiency through foliar fertilization, (2) Second screen for Zn, Cu, and Cd accumulation, (3) Characterization of the root Zn hyperaccumulation by Thlaspi caerulescens, (4) Comparison of commercial Brassica accessions obtained from the Iowa seed bank, (5) Second screening experiment for the accumulation of Cs and Sr by plants, (6) Effect of Ca on Cs and Sr accumulation by selected dicot species, and (7) Preliminary investigations into the forms of uranium taken up by plants.

  1. Accumulation and hyperaccumulation of copper in plants

    NASA Astrophysics Data System (ADS)

    Adam, V.; Trnkova, L.; Huska, D.; Babula, P.; Kizek, R.

    2009-04-01

    Copper is natural component of our environment. Flow of copper(II) ions in the environment depends on solubility of compounds containing this metal. Mobile ion coming from soil and rocks due to volcanic activity, rains and others are then distributed to water. Bio-availability of copper is substantially lower than its concentration in the aquatic environment. Copper present in the water reacts with other compounds and creates a complex, not available for organisms. The availability of copper varies depending on the environment, but moving around within the range from 5 to 25 % of total copper. Thus copper is stored in the sediments and the rest is transported to the seas and oceans. It is common knowledge that copper is essential element for most living organisms. For this reason this element is actively accumulated in the tissues. The total quantity of copper in soil ranges from 2 to 250 mg / kg, the average concentration is 30 mg / kg. Certain activities related to agriculture (the use of fungicides), possibly with the metallurgical industry and mining, tend to increase the total quantity of copper in the soil. This amount of copper in the soil is a problem particularly for agricultural production of food. The lack of copper causes a decrease in revenue and reduction in quality of production. In Europe, shows the low level of copper in total 18 million hectares of farmland. To remedy this adverse situation is the increasing use of copper fertilizers in agricultural soils. It is known that copper compounds are used in plant protection against various illnesses and pests. Mining of minerals is for the development of human society a key economic activity. An important site where the copper is mined in the Slovakia is nearby Smolníka. Due to long time mining in his area (more than 700 years) there are places with extremely high concentrations of various metals including copper. Besides copper, there are also detected iron, zinc and arsenic. Various plant species have adapted on such stress. The aim of this study is to investigate the behaviour of copper in plants and to assess its potential effect on the surrounding environment. To detect copper in biological samples electrochemical methods were employed particularly differential pulse voltammetry (DPV). Copper gave signals at 0.02 V measured by DPV. The obtained calibration dependence was linear (R2 = 0.995). Further, this method was utilized for determination of copper in real soil samples obtained from previously mentioned heavy-metal-polluted mining area. The content varied within range from tens to hundreds of mg of copper per kg of the soil. Moreover, we focused on investigation of copper influence on seedlings of Norway spruce. The seedlings were treated with copper (0, 0.1, 10 and 100 mM) for four weeks. We observed anatomical-morphological changes and other biochemical parameters in plants. We determined that seedlings synthesized more than 48 % protective thiols (glutathione and phytochelatins) compared to control ones. We investigated copper distribution in plant tissues by diphenylcarbazide staining. We found out that copper is highly accumulated in parenchymal stalk cells. In needles, change in auto-fluorescence of parenchymal cells of mesoderm similarly to endodermis cells. Besides, we analyzed samples of plants from the polluted area (spruce, pin, birch). The data obtained well correlated with previously mentioned. Acknowledgement The work on this experiment was supported by grant: INCHEMBIOL MSM0021622412.

  2. Genetic and Molecular Dissection of Arsenic Hyperaccumulation

    SciTech Connect

    Banks, Jo Ann

    2005-06-01

    We have constructed cDNA libraries from RNA isolated from arsenic treated gametophytes of the fern Pteris vittata. This library was made in a manner that allows each cDNA clone to be expressed in yeast. We have introduced this library into yeast cells, both wild type and arsensic sensitive mutants, and selected transformed yeast colonies with increased arsenic tolerance compared to the parental strains. From these screens we have identified putative homologs of the yeast ACR2 and ACR3 genes from Pteris vittata and, for the past year, have focused on characterizing the function of the ACR2 gene. In yeast, ACR2 is an arsenate reductase that is essential for arsenate tolerance. We refer to the Pteris vittata ACR2 gene as PvACR2. The deduced amino acid sequence of PvACR2 is highly similar to the yeast ACR2 and other related phosphatases.

  3. Phytoremediation of heavy metal polluted soils and water: Progresses and perspectives*

    PubMed Central

    Lone, Mohammad Iqbal; He, Zhen-li; Stoffella, Peter J.; Yang, Xiao-e

    2008-01-01

    Environmental pollution affects the quality of pedosphere, hydrosphere, atmosphere, lithosphere and biosphere. Great efforts have been made in the last two decades to reduce pollution sources and remedy the polluted soil and water resources. Phytoremediation, being more cost-effective and fewer side effects than physical and chemical approaches, has gained increasing popularity in both academic and practical circles. More than 400 plant species have been identified to have potential for soil and water remediation. Among them, Thlaspi, Brassica, Sedum alfredii H., and Arabidopsis species have been mostly studied. It is also expected that recent advances in biotechnology will play a promising role in the development of new hyperaccumulators by transferring metal hyperaccumulating genes from low biomass wild species to the higher biomass producing cultivated species in the times to come. This paper attempted to provide a brief review on recent progresses in research and practical applications of phytoremediation for soil and water resources. PMID:18357623

  4. Histidine-mediated xylem loading of zinc is a species-wide character in Noccaea caerulescens.

    PubMed

    Kozhevnikova, Anna D; Seregin, Ilya V; Erlikh, Nadezhda T; Shevyreva, Taisiya A; Andreev, Igor M; Verweij, Rudo; Schat, Henk

    2014-07-01

    Histidine plays a crucial role in nickel (Ni) translocation in Ni-hyperaccumulating plants. Here, we investigated its role in zinc (Zn) translocation in four accessions of the Zn hyperaccumulator, Noccaea caerulescens, using the related non-hyperaccumulator, Thlaspi arvense, as a reference. We compared the effects of exogenous histidine supply on Zn xylem loading, and of Zn-histidine complex formation on Zn uptake in energized tonoplast vesicles. The Zn distribution patterns over root tissues were also compared. Exogenous histidine supply enhanced Zn xylem loading in all the N. caerulescens accessions, but decreased it in T. arvense. Zn distribution patterns over root tissues were similar, apart from the accumulation in cortical and endodermal cells, which was much lower in N. caerulescens than in T. arvense. Zn uptake in energized tonoplast vesicles was inhibited significantly in N. caerulescens, but not affected significantly in T. arvense, when Zn was supplied in combination with histidine in a 1:2 molar ratio. Histidine-mediated Zn xylem loading seems to be a species-wide character in N. caerulescens. It may well have evolved as a component trait of the hyperaccumulation machinery for Zn, rather than for Ni.

  5. Interactions between plant and rhizosphere microbial communities in a metalliferous soil.

    PubMed

    Epelde, Lur; Becerril, José M; Barrutia, Oihana; González-Oreja, José A; Garbisu, Carlos

    2010-05-01

    In the present work, the relationships between plant consortia, consisting of 1-4 metallicolous pseudometallophytes with different metal-tolerance strategies (Thlaspi caerulescens: hyperaccumulator; Jasione montana: accumulator; Rumex acetosa: indicator; Festuca rubra: excluder), and their rhizosphere microbial communities were studied in a mine soil polluted with high levels of Cd, Pb and Zn. Physiological response and phytoremediation potential of the studied pseudometallophytes were also investigated. The studied metallicolous populations are tolerant to metal pollution and offer potential for the development of phytoextraction and phytostabilization technologies. T. caerulescens appears very tolerant to metal stress and most suitable for metal phytoextraction; the other three species enhance soil functionality. Soil microbial properties had a stronger effect on plant biomass rather than the other way around (35.2% versus 14.9%). An ecological understanding of how contaminants, ecosystem functions and biological communities interact in the long-term is needed for proper management of these fragile metalliferous ecosystems.

  6. IN VIVO SYNCHROTRON INVESTIGATION OF THALLIUM HYPERACCUMULATION - I

    EPA Science Inventory

    Thallium (TI) is a metal of great toxicological concern and its prevalence in the natural environment has steadily increased as a result of manufacturing and combustion practices. Due to its low natural abundance and the increasing demand, TI recovery and reuse could be a profita...

  7. PHYTOREMEDIATION OF INORGANICS: REALISM AND SYNERGIES.

    PubMed

    Dickinson, Nicholas M; Baker, Alan J M; Doronila, Augustine; Laidlaw, Scott; Reeves, Roger D

    2009-02-01

    There are very few practical demonstrations of the phytoextraction of metals and metalloids from soils and sediments beyond small-scale and short-term trials. The two approaches used have been based on using 1) hyperaccumulator species, such as Thlaspi caerulescens (Pb, Zn, Cd, Ni), Alyssum spp. (Ni, Co), and Pteris vittata (As) or 2) fast-growing plants, such as Salix and Populus spp. that accumulate above-average concentrations of only a smaller number of the more mobile trace elements (Cd, Zn, B). Until we have advanced much more along the pathway of genetic isolation and transfer of hyperaccumulator traits into productive plants, there is a high risk in marketing either approach as a technology or stand-alone solution to clean up contaminated land. There are particular uncertainties over the longer-term effectiveness of phytoextraction and associated environmental issues. Marginally contaminated agricultural soils provide the most likely land use where phytoextraction can be used as a polishing technology. An alternative and more useful practical approach in many situations currently would be to give more attention to crops selected for phytoexclusion: selecting crops that do not translocate high concentrations of metals to edible parts. Soils of brownfield, urban, and industrial areas provide a large-scale opportunity to use phytoremediation, but the focus here should be on the more realistic possibilities of risk-managed phytostabilization and monitored natural attenuation. We argue that the wider practical applications of phytoremediation are too often overlooked. There is huge scope for cross-cutting other environmental agenda, with synergies that involve the recovery and provision of services from degraded landscapes and contaminated soils. An additional focus on biomass energy, improved biodiversity, watershed management, soil protection, carbon sequestration, and improved soil health is required for the justification and advancement of phytotechnologies.

  8. Cadmium-zinc accumulation and photosystem II responses of Noccaea caerulescens to Cd and Zn exposure.

    PubMed

    Bayçu, Gülriz; Gevrek-Kürüm, Nurbir; Moustaka, Julietta; Csatári, István; Rognes, Sven Erik; Moustakas, Michael

    2017-01-01

    A population of the metallophyte Noccaea (Thlaspi) caerulescens originating from a Zn-enriched area at Røros Copper Mine (Norway) was studied. N. caerulescens tolerance to accumulate Cd and Zn was evaluated in hydroponic experiments by chlorophyll fluorescence imaging analysis. In the field-collected N. caerulescens mother plants, Zn shoot concentrations were above Zn hyperaccumulation threshold while, in hydroponic experiments under 40-μM Cd exposure, shoot Cd concentrations were clearly above Cd hyperaccumulation threshold. Cadmium ions and, to a less extent, Zn were mainly retained in the roots. Exposure to Cd enhanced Zn translocation to the shoot, while decreased significant total Ca(2+) uptake, suggesting that Cd uptake occurs through Ca(2+) transporters. Nevertheless, it increased Ca(2+) translocation to the leaf, possibly for photoprotection of photosystem II (PSII). Exposure to 800 μM Zn or 40 μM Cd resulted in increased Fe(3+) uptake suggesting that in N. caerulescens, Cd uptake does not take place through the pathway of Fe(3+) uptake and that conditions that lead to Cd and Zn accumulation in plants may also favor Fe accumulation. Despite the significant high toxicity levels of Zn and Cd in leaves, under Zn and Cd exposure, respectively, the allocation of absorbed light energy at PSII did not differ compared to controls. The results showed that N. caerulescens keep Cd and Zn concentrations in the mesophyll cells in non-toxic forms for PSII and that the increased Ca and Fe accumulation in leaves alleviates the toxicity effects. Chlorophyll fluorescence imaging revealed that PSII of N. caerulescens resisted better the phytotoxic effects of 20 times higher Zn than Cd exposure concentration. Overall, it is concluded that the use of chlorophyll fluorescence imaging constitutes a promising basis for investigating heavy metal tolerance of plants.

  9. Remediation of cadmium contaminated irrigation and drinking water: a large scale approach.

    PubMed

    Bandara, J M R S; Wijewardena, H V P; Seneviratne, H M M S

    2010-09-15

    Cadmium is one of the most troublesome toxic heavy metals. It accumulates in the water reservoirs and agricultural soil as a result of intensive use of Cd contaminated phosphate fertilizers, e.g. in agriculture in the North Central Province (NCP) of Sri Lanka. The hyper-accumulator Thlaspi caerulescens, accumulates up to 1000 ppm Cd in shoots without exhibiting toxicity symptoms. The storage rhizomes of year old Nelumbo nucifera (lotus) natural vegetation in water reservoirs in NCP accumulated 253+/-12 mg Cd/kg. Seedlings of lotus grown in 5% Hoagland's solution at 0.75, 1.0 and 1.25 ppm cadmium sulphate showed a significant increase in Cd removal of 0.0334-0.121 ppm/week. However the removal rate of Cd from water failed to increase any further at higher concentrations of Cd in water. The slow growth rate and low rate of phytoextraction demands a more effective but an affordable method of remediation in order to combat the prevailing elevated cadmium levels in NCP that causes chronic renal failure (CRF). We have developed a large scale filtering device using rice husk. We have achieved successful results in sequestering Cd using raw rice husk as well as amorphous silica derived from rice husk.

  10. Cadmium accumulation is enhanced by ammonium compared to nitrate in two hyperaccumulators, without affecting speciation

    PubMed Central

    Cheng, Miaomiao; Wang, Peng; Kopittke, Peter M.; Wang, Anan; Sale, Peter W.G.

    2016-01-01

    Nitrogen fertilization could improve the efficiency of Cd phytoextraction in contaminated soil and thus shorten the remediation time. However, limited information is available on the effect of N form on Cd phytoextraction and associated mechanisms in plants. This study examined the effect of N form on Cd accumulation, translocation, and speciation in Carpobrotus rossii and Solanum nigrum. Plants were grown in nutrient solution with 5–15 μM Cd in the presence of 1000 µM NH4 + or NO3 −. Plant growth and Cd uptake were measured, and Cd speciation was analyzed using synchrotron-based X-ray absorption spectroscopy. Shoot Cd accumulation was 30% greater with NH4 + than NO3 − supply. Carpobrotus rossii accumulated three times more Cd than S. nigrum. However, Cd speciation in the plants was not influenced by N form, but it did vary with species and tissues. In C. rossii, up to 91% of Cd was bound to S-containing ligands in all tissues except the xylem sap where 87–95% were Cd-OH complexes. Furthermore, the proportion of Cd-S in shoots was substantially lower in S. nigrum (44–69%) than in C. rossii (60–91%). It is concluded that the application of NH4 + (instead of NO3 −) increased shoot Cd accumulation by increasing uptake and translocation, rather than changing Cd speciation, and is potentially an effective approach for increasing Cd phytoextraction. PMID:27385767

  11. Mechanisms of nickel uptake, and hyperaccumulation by plants and implications to soil remediation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil contamination by heavy metals like Ni was originally restricted to metalliferous soils but in recent years it has become a general problem due to the increasingly frequent anthropogenic activities. Because of the characteristics of cost-effectiveness, environmental friendliness, and fewer side...

  12. Microbial community dynamics in the rhizosphere of a cadmium hyper-accumulator

    PubMed Central

    Wood, J. L.; Zhang, C.; Mathews, E. R.; Tang, C.; Franks, A. E.

    2016-01-01

    Phytoextraction is influenced by the indigenous soil microbial communities during the remediation of heavy metal contaminated soils. Soil microbial communities can affect plant growth, metal availability and the performance of phytoextraction-assisting inocula. Understanding the basic ecology of indigenous soil communities associated with the phytoextraction process, including the interplay between selective pressures upon the communities, is an important step towards phytoextraction optimization. This study investigated the impact of cadmium (Cd), and the presence of a Cd-accumulating plant, Carpobrotus rossii (Haw.) Schwantes, on the structure of soil-bacterial and fungal communities using automated ribosomal intergenic spacer analysis (ARISA) and quantitative PCR (qPCR). Whilst Cd had no detectable influence upon fungal communities, bacterial communities underwent significant structural changes with no reduction in 16S rRNA copy number. The presence of C. rossii influenced the structure of all communities and increased ITS copy number. Suites of operational taxonomic units (OTUs) changed in abundance in response to either Cd or C. rossii, however we found little evidence to suggest that the two selective pressures were acting synergistically. The Cd-induced turnover in bacterial OTUs suggests that Cd alters competition dynamics within the community. Further work to understand how competition is altered could provide a deeper understanding of the microbiome-plant-environment and aid phytoextraction optimization. PMID:27805014

  13. Zinc Hyperaccumulation in Squirrelfish (Holocentrus adscenscionis) and Its Role in Embryo Viability

    PubMed Central

    Glover, Chris N.; Capo, Tom; Walsh, Patrick J.; Hogstrand, Christer

    2012-01-01

    Female squirrelfish (Fam. Holocentridae) can accumulate and temporarily sequester copious amounts of zinc (Zn) in their livers. There, it is initially compartmentalized before a subsequent, estrogen-triggered redistribution to the ovaries. Here we show that cellular uptake of Zn is also influenced by estrogen signaling, and that estrogen increases concentrations of the plasma Zn-binding protein vitellogenin (VTG). However, estrogen-mediated increases in VTG are not sufficient to accommodate the magnitude of hepato-ovarian Zn transfer in female squirrelfish (Holocentrus adscensionis). These findings suggest that holocentrids have acquired the ability to use hormonal cues to drive hepatic uptake and storage of Zn, signal for its physiological redistribution, and influence the capacity for systemic transport of Zn beyond the mediation of increased plasma VTG concentrations. Such specific adaptations suggest an advantage for the oocyte, which is corroborated in further studies where we determined that oocyte Zn concentrations are positively correlated with egg viability in captive-spawned squirrelfish. The novel nature of these findings underlies the importance of Zn in squirrelfish reproductive biology. PMID:23056248

  14. Chemical Form and Distribution of Selenium and Sulfur in the Selenium Hyperaccumulator Astragalus bisulcatus1

    PubMed Central

    Pickering, Ingrid J.; Wright, Carrie; Bubner, Ben; Ellis, Danielle; Persans, Michael W.; Yu, Eileen Y.; George, Graham N.; Prince, Roger C.; Salt, David E.

    2003-01-01

    In its natural habitat, Astragalus bisulcatus can accumulate up to 0.65% (w/w) selenium (Se) in its shoot dry weight. X-ray absorption spectroscopy has been used to examine the selenium biochemistry of A. bisulcatus. High concentrations of the nonprotein amino acid Se-methylseleno-cysteine (Cys) are present in young leaves of A. bisulcatus, but in more mature leaves, the Se-methylseleno-Cys concentration is lower, and selenate predominates. Seleno-Cys methyltransferase is the enzyme responsible for the biosynthesis of Se-methylseleno-Cys from seleno-Cys and S-methyl-methionine. Seleno-Cys methyltransferase is found to be expressed in A. bisulcatus leaves of all ages, and thus the biosynthesis of Se-methylseleno-Cys in older leaves is limited earlier in the metabolic pathway, probably by an inability to chemically reduce selenate. A comparative study of sulfur (S) and Se in A. bisulcatus using x-ray absorption spectroscopy indicates similar trends for oxidized and reduced Se and S species, but also indicates that the proportions of these differ significantly. These results also indicate that sulfate and selenate reduction are developmentally correlated, and they suggest important differences between S and Se biochemistries. PMID:12644695

  15. Cadmium accumulation is enhanced by ammonium compared to nitrate in two hyperaccumulators, without affecting speciation.

    PubMed

    Cheng, Miaomiao; Wang, Peng; Kopittke, Peter M; Wang, Anan; Sale, Peter W G; Tang, Caixian

    2016-09-01

    Nitrogen fertilization could improve the efficiency of Cd phytoextraction in contaminated soil and thus shorten the remediation time. However, limited information is available on the effect of N form on Cd phytoextraction and associated mechanisms in plants. This study examined the effect of N form on Cd accumulation, translocation, and speciation in Carpobrotus rossii and Solanum nigrum Plants were grown in nutrient solution with 5-15 μM Cd in the presence of 1000 µM NH4 (+) or NO3 (-) Plant growth and Cd uptake were measured, and Cd speciation was analyzed using synchrotron-based X-ray absorption spectroscopy. Shoot Cd accumulation was 30% greater with NH4 (+) than NO3 (-) supply. Carpobrotus rossii accumulated three times more Cd than S. nigrum. However, Cd speciation in the plants was not influenced by N form, but it did vary with species and tissues. In C. rossii, up to 91% of Cd was bound to S-containing ligands in all tissues except the xylem sap where 87-95% were Cd-OH complexes. Furthermore, the proportion of Cd-S in shoots was substantially lower in S. nigrum (44-69%) than in C. rossii (60-91%). It is concluded that the application of NH4 (+) (instead of NO3 (-)) increased shoot Cd accumulation by increasing uptake and translocation, rather than changing Cd speciation, and is potentially an effective approach for increasing Cd phytoextraction.

  16. Copper localization, elemental content, and thallus colour in the copper hyperaccumulator lichen Lecanora sierra from California

    USGS Publications Warehouse

    Purvis, O.W.; Bennett, J.P.; Spratt, J.

    2011-01-01

    An unusual dark blue-green lichen, Lecanora sierrae, was discovered over 30 years ago by Czehura near copper mines in the Lights Creek District, Plumas County, Northern California. Using atomic absorption spectroscopy, Czehura found that dark green lichen samples from Warren Canyon contained 4% Cu in ash and suggested that its colour was due to copper accumulation in the cortex. The present study addressed the hypothesis that the green colour in similar material we sampled from Warren Canyon in 2008, is caused by copper localization in the thallus. Optical microscopy and electron microprobe analysis of specimens of L. sierrae confirmed that copper localization took place in the cortex. Elemental analyses of L. sierrae and three other species from the same localities showed high enrichments of copper and selenium, suggesting that copper selenates or selenites might occur in these lichens and be responsible for the unusual colour.

  17. Copper localization, elemental content, and thallus colour in the copper hyperaccumulator lichen Lecanora sierrae from California

    USGS Publications Warehouse

    Purvis, O.W.; Bennett, J.P.; Spratt, J.

    2011-01-01

    An unusual dark blue-green lichen, Lecanora sierrae, was discovered over 30 years ago by Czehura near copper mines in the Lights Creek District, Plumas County, Northern California. Using atomic absorption spectroscopy, Czehura found that dark green lichen samples from Warren Canyon contained 4% Cu in ash and suggested that its colour was due to copper accumulation in the cortex. The present study addressed the hypothesis that the green colour in similar material we sampled from Warren Canyon in 2008, is caused by copper localization in the thallus. Optical microscopy and electron microprobe analysis of specimens of L. sierrae confirmed that copper localization took place in the cortex. Elemental analyses of L. sierrae and three other species from the same localities showed high enrichments of copper and selenium, suggesting that copper selenates or selenites might occur in these lichens and be responsible for the unusual colour. Copyright ?? 2011 British Lichen Society.

  18. Microbial community dynamics in the rhizosphere of a cadmium hyper-accumulator

    NASA Astrophysics Data System (ADS)

    Wood, J. L.; Zhang, C.; Mathews, E. R.; Tang, C.; Franks, A. E.

    2016-11-01

    Phytoextraction is influenced by the indigenous soil microbial communities during the remediation of heavy metal contaminated soils. Soil microbial communities can affect plant growth, metal availability and the performance of phytoextraction-assisting inocula. Understanding the basic ecology of indigenous soil communities associated with the phytoextraction process, including the interplay between selective pressures upon the communities, is an important step towards phytoextraction optimization. This study investigated the impact of cadmium (Cd), and the presence of a Cd-accumulating plant, Carpobrotus rossii (Haw.) Schwantes, on the structure of soil-bacterial and fungal communities using automated ribosomal intergenic spacer analysis (ARISA) and quantitative PCR (qPCR). Whilst Cd had no detectable influence upon fungal communities, bacterial communities underwent significant structural changes with no reduction in 16S rRNA copy number. The presence of C. rossii influenced the structure of all communities and increased ITS copy number. Suites of operational taxonomic units (OTUs) changed in abundance in response to either Cd or C. rossii, however we found little evidence to suggest that the two selective pressures were acting synergistically. The Cd-induced turnover in bacterial OTUs suggests that Cd alters competition dynamics within the community. Further work to understand how competition is altered could provide a deeper understanding of the microbiome-plant-environment and aid phytoextraction optimization.

  19. Bioenergy crops grown for hyperaccumulation of phosphorus in the delmarva peninsula and their biofuels potential

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Herbaceous bioenergy crops, including sorghum, switchgrass, and miscanthus, were evaluated for their potential as phytoremedators for the uptake of phosphorus in the Delmarva Peninsula and their subsequent conversion to biofuel intermediates (bio-oil) by fast pyrolysis using pyrolysis-gas chromatogr...

  20. Bioenergy crops grown for hyperaccumulation of phosphorous in the Delmarva Peninsula and their biofuels potential.

    PubMed

    Boateng, Akwasi A; Serapiglia, Michelle J; Mullen, Charles A; Dien, Bruce S; Hashem, Fawzy M; Dadson, Robert B

    2015-03-01

    Herbaceous bioenergy crops, including sorghum, switchgrass, and miscanthus, were evaluated for their potential as phytoremediators for the uptake of phosphorus in the Delmarva Peninsula and their subsequent conversion to biofuel intermediates (bio-oil) by fast pyrolysis using pyrolysis-gas chromatography/mass spectroscopy. Four cultivars of sorghum, five cultivars of switchgrass and one miscanthus (Miscanthus × giganteus) were grown in soils with two different levels of poultry manure (PM) applications. Little variation was seen in phosphorus uptake in the two different soils indicating that the levels of available phosphorus in the soil already saturated the uptake ability of the plants. However, all plants regardless of trial took up more phosphorus than that measured for the non- PM treated control. Sorghum accumulated greater levels of nutrients including phosphorus and potassium compared to switchgrass and miscanthus. The levels of these nutrients in the biomass did not have an effect on carbohydrate contents. However, the potential yield and composition of bio-oil from fast pyrolysis were affected by both agronomics and differences in mineral concentrations.

  1. Are plants growing at abandoned mine sites suitable for phytoremediation of contaminated soils?

    NASA Astrophysics Data System (ADS)

    Bini, Claudio; Buffa, Gabriella; Fontana, Silvia; Wahsha, Mohammad

    2013-04-01

    Plants growing on abandoned mine sites are of particular interest in the perspective to remediate contaminated soils by phytoremediation, a low cost and environmental friendly technique which uses metal-accumulator plants to clean up moderately contaminated areas. The choice of plants is a crucial aspect for the practical use of this technique, given the ability to accumulate metals in their tissues, being genetically tolerant to high metal concentrations. Up today, more than 400 native plants that hyperaccumulate metals are reported, Brassicaceae being the family with the largest number of hyperaccumulator species. For example, Alyssum bertoloni is well known as Ni accumulator, as well as Thlaspi caerulescens for Zn and Brassica napus for Pb. However, metal hyperaccumulation is not a common phenomenon in terrestrial higher plants, and many of the European hyperaccumulator plants are of small biomass, and have a slow growth rate. Therefore, there is an urgent need for surveying and screening of plants with ability to accumulate metals in their tissues and a relatively high biomass. In recent years, a survey of soils and plants growing on contaminated areas at several abandoned sulphide mines in Italy was carried out by working groups of the Universities of Florence, Siena, Cagliari, Bologna, Udine and Venice, in order to evaluate the ability of these plants to colonize mine waste and to accumulate metals, in the perspective of an ecological restoration of contaminated sites. We investigated the heavy metal concentration of the waste material, and the soils developed from, in order to determine the extent of heavy metal dispersion, and the uptake by plants, and deserved attention to wild plants growing at that sites, to find out new metal-tolerant species to utilize in soil remediation. Current results of these investigations, with particular emphasis on the Tuscan areas, are reported here. All the studied profiles are strongly enriched in metals; their

  2. Chelant-assisted phytoextraction and accumulation of Zn by Zea mays.

    PubMed

    Gheju, M; Stelescu, I

    2013-10-15

    Zea mays plants were exposed to soils with concentrations of Zn ranging from 64 to 1800 mg kg(-1) dw, and the efficiency of three selected chelating agents (trisodium citrate (CI), disodium oxalate (OX) and disodium dihydrogen ethylene-diamine-tetraacetate (EDTA)) in enhancing metal phytoextraction was compared. Zn concentration in plant tissues increased in conjunction with the metal concentration of the soil. EDTA was found to be the most efficient chelating amendment, increasing concentrations of Zn in shoots from 88 mg kg(-1) dw, at 64 mg kg(-1) dw soil, to 8026 mg kg(-1) dw at 1800 mg kg(-1) dw soil. The overall orders of BCFs and TFs which resulted from this study are: EDTA > H2O > OX > CI, and EDTANa2 > OX > CI > H2O, respectively. The more effective uptake of Zn by plants for the control treatment (distilled water only) than for CI and OX was attributed to the neutral or slightly alkaline pH of the two chelant irrigation solutions. Instead, EDTA had a favorable effect on Zn uptake from soil due to its additive chelating and acidifying properties. Among the three chelants, only EDTA significantly increased the Zn phytoextraction potential of Z. mays, while CI and OX induced a low metal uptake from soil by plants. Although Z. mays has a lower Zn accumulation capacity than the hyperaccumulator Thlaspi caerulescens, it could be considered as a potential phytoremediator of soils with elevated Zn concentrations, especially when metal pollution extends to depths greater than 20 cm.

  3. Heap leaching of lead contaminated soil using biodegradable chelator [S,S]-ethylenediamine disuccinate.

    PubMed

    Finzgar, N; Kos, B; Lestan, D

    2005-05-01

    The feasibility of heap leaching Pb contaminated soil using biodegradable chelator [S,S]-ethylenediamine disuccinate ([S,S]-EDDS) in concentrations ranging from 10 to 40 mmol kg(-1) was assessed in a laboratory study. Treatment with 40 mmol kg(-1) [S,S]-EDDS was the most efficient, removing 31.3% of soil Pb and producing a waste washing solution with a peak Pb concentration slightly exceeding 10 mM. The removal of Pb from simulated washing solution containing 10 mM Pb by biodegradation of the Pb-[S,S]-EDDS complex and sorption of the released Pb on a vermiculite/soya meal/Slovakite based permeable bed was completed in 7.5 days. Lead recovery from washing solutions with higher molarity was significantly slower. Lead fractionation and bioavailability were assessed 6-months after soil treatment. Heap leaching removed Pb proportionally from carbonates (approx. 25% Pb) and organic matter (> 50% Pb), the two main Pb-bearing soil fractions,and increased the small pool of Pb soluble in the soil solution. The latter had no effect on Pb phytoavailability. Accumulation of Pb in leaves of the reported hyperaccumulator species Thlaspi goesingense was < 20 mg kg(-1) in all treatments, comparable to the Pb concentration in lettuce (Latuca sativa). Soil treatment with 40 mmol kg(-1) [S,S]-EDDS reduced concentrations of Pb orally-accessible in the stomach and intestine phase from initial 234.0 and 52.5 mg kg(-1) to 157.8 and 29.7 mg kg(-1), respectively, according to Ruby's test. Our results indicate that heap leaching of Pb with [S,S]-EDDS is not a viable remediation option for the tested soil and conditions used.

  4. The investigation of the possibility for using some wild and cultivated plants as hyperaccumulators of heavy metals from contaminated soil.

    PubMed

    Maric, Miroslava; Antonijevic, Milan; Alagic, Sladjana

    2013-02-01

    The copper production in Bor (East Serbia) during the last 100 years presents an important source of the pollution of environment. Dust, waste waters, tailing, and air pollutants influence the quality of soil, water, and air. Over 2,000 ha of fertile soil have been damaged by the flotation tailing from Bor's facilities. The goal of the present work has been to determine the content of Pb, Cu, and Fe in wild plants (17 species) naturally growing in the damaged soil and in fodder crops (nine species) planted at the same place. The content of Pb, Cu, and Fe has been analyzed in damaged soil as well. This study has also searched for native (wild) and cultivated plants which are able to grow in contaminated soil in the area of the intense industrial activity of copper production in Bor, which means that they can accumulate and tolerate heavy metals in their above-ground tissues. It has been found out that the content of all metals in contaminated soil decreases considerably at the end of the experiment. As it has been expected, all plant species could accumulate investigated metals. All tested plants, both wild-growing and cultivated plants, seem to be quite healthy on the substrate which contained extremely high concentrations of copper.

  5. Impact assessment of mercury accumulation and biochemical and molecular response of Mentha arvensis: a potential hyperaccumulator plant.

    PubMed

    Manikandan, R; Sahi, S V; Venkatachalam, P

    2015-01-01

    The present study was focused on examining the effect of Hg oxidative stress induced physiochemical and genetic changes in M. arvensis seedlings. The growth rate of Hg treated seedlings was decreased to 56.1% and 41.5% in roots and shoots, respectively, compared to the control. Accumulation of Hg level in both roots and shoots was increased with increasing the concentration of Hg. Superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities were found to be increased with increasing the Hg concentration up to 20 mg/L; however, it was decreased at 25 mg/L Hg concentration. The POX enzyme activity was positively correlated with Hg dose. The changes occurring in the random amplification of ploymorphic DNA (RAPD) profiles generated from Hg treated seedlings included variations in band intensity, disappearance of bands, and appearance of new bands compared with the control seedlings. It was concluded that DNA polymorphisms observed with RAPD profile could be used as molecular marker for the evaluation of heavy metal induced genotoxic effects in plant species. The present results strongly suggested that Mentha arvensis could be used as a potential phytoremediator plant in mercury polluted environment.

  6. Intraspecific variability of cadmium tolerance and accumulation, and cadmium-induced cell wall modifications in the metal hyperaccumulator Arabidopsis halleri

    PubMed Central

    Meyer, Claire-Lise; Juraniec, Michal; Huguet, Stéphanie; Chaves-Rodriguez, Elena; Salis, Pietro; Isaure, Marie-Pierre; Goormaghtigh, Erik; Verbruggen, Nathalie

    2015-01-01

    Certain molecular mechanisms of Cd tolerance and accumulation have been identified in the model species Arabidopsis halleri, while intraspecific variability of these traits and the mechanisms of shoot detoxification were little addressed. The Cd tolerance and accumulation of metallicolous and non-metallicolous A. halleri populations from different genetic units were tested in controlled conditions. In addition, changes in shoot cell wall composition were investigated using Fourier transform infrared spectroscopy. Indeed, recent works on A. halleri suggest Cd sequestration both inside cells and in the cell wall/apoplast. All A. halleri populations tested were hypertolerant to Cd, and the metallicolous populations were on average the most tolerant. Accumulation was highly variable between and within populations, and populations that were non-accumulators of Cd were identified. The effect of Cd on the cell wall composition was quite similar in the sensitive species A. lyrata and in A. halleri individuals; the pectin/polysaccharide content of cell walls seems to increase after Cd treatment. Nevertheless, the changes induced by Cd were more pronounced in the less tolerant individuals, leading to a correlation between the level of tolerance and the extent of modifications. This work demonstrated that Cd tolerance and accumulation are highly variable traits in A. halleri, suggesting adaptation at the local scale and involvement of various molecular mechanisms. While in non-metallicolous populations drastic modifications of the cell wall occur due to higher Cd toxicity and/or Cd immobilization in this compartment, the increased tolerance of metallicolous populations probably involves other mechanisms such as vacuolar sequestration. PMID:25873677

  7. Impact Assessment of Mercury Accumulation and Biochemical and Molecular Response of Mentha arvensis: A Potential Hyperaccumulator Plant

    PubMed Central

    Manikandan, R.; Sahi, S. V.; Venkatachalam, P.

    2015-01-01

    The present study was focused on examining the effect of Hg oxidative stress induced physiochemical and genetic changes in M. arvensis seedlings. The growth rate of Hg treated seedlings was decreased to 56.1% and 41.5% in roots and shoots, respectively, compared to the control. Accumulation of Hg level in both roots and shoots was increased with increasing the concentration of Hg. Superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities were found to be increased with increasing the Hg concentration up to 20 mg/L; however, it was decreased at 25 mg/L Hg concentration. The POX enzyme activity was positively correlated with Hg dose. The changes occurring in the random amplification of ploymorphic DNA (RAPD) profiles generated from Hg treated seedlings included variations in band intensity, disappearance of bands, and appearance of new bands compared with the control seedlings. It was concluded that DNA polymorphisms observed with RAPD profile could be used as molecular marker for the evaluation of heavy metal induced genotoxic effects in plant species. The present results strongly suggested that Mentha arvensis could be used as a potential phytoremediator plant in mercury polluted environment. PMID:25654134

  8. Immunocytochemical analysis of the subcellular distribution of ferritin in Imperata cylindrica (L.) Raeuschel, an iron hyperaccumulator plant.

    PubMed

    de la Fuente, Vicenta; Rodríguez, Nuria; Amils, Ricardo

    2012-05-01

    Ferritin is of interest at the structural and functional level not only as storage for iron, a critical element, but also as a means to prevent cell damage produced by oxidative stress. The main objective of this work was to confirm by immunocytochemistry the presence and the subcellular distribution of the ferritin detected by Mösbauer spectroscopy in Imperata cylindrica, a plant which accumulates large amounts of iron. The localization of ferritin was performed in epidermal, parenchymal and vascular tissues of shoots and leaves of I. cylindrica. The highest density of immunolabeling in shoots appeared in the intracellular space of cell tissues, near the cell walls and in the cytoplasm. In leaves, ferritin was detected in the proximity of the dense network of the middle lamella of cell walls, following a similar path to that observed in shoots. Immunolabeling was also localized in chloroplasts. The abundance of immunogold labelling in mitochondria for I. cylindrica was rather low, probably because the study dealt with tissues from old plants. These results further expand the localization of ferritin in cell components other than chloroplasts and mitochondria in plants.

  9. Rhizosphere Microbial Community Composition Affects Cadmium and Zinc Uptake by the Metal-Hyperaccumulating Plant Arabidopsis halleri

    PubMed Central

    Muehe, E. Marie; Weigold, Pascal; Adaktylou, Irini J.; Planer-Friedrich, Britta; Kraemer, Ute; Kappler, Andreas

    2015-01-01

    The remediation of metal-contaminated soils by phytoextraction depends on plant growth and plant metal accessibility. Soil microorganisms can affect the accumulation of metals by plants either by directly or indirectly stimulating plant growth and activity or by (im)mobilizing and/or complexing metals. Understanding the intricate interplay of metal-accumulating plants with their rhizosphere microbiome is an important step toward the application and optimization of phytoremediation. We compared the effects of a “native” and a strongly disturbed (gamma-irradiated) soil microbial communities on cadmium and zinc accumulation by the plant Arabidopsis halleri in soil microcosm experiments. A. halleri accumulated 100% more cadmium and 15% more zinc when grown on the untreated than on the gamma-irradiated soil. Gamma irradiation affected neither plant growth nor the 1 M HCl-extractable metal content of the soil. However, it strongly altered the soil microbial community composition and overall cell numbers. Pyrosequencing of 16S rRNA gene amplicons of DNA extracted from rhizosphere samples of A. halleri identified microbial taxa (Lysobacter, Streptomyces, Agromyces, Nitrospira, “Candidatus Chloracidobacterium”) of higher relative sequence abundance in the rhizospheres of A. halleri plants grown on untreated than on gamma-irradiated soil, leading to hypotheses on their potential effect on plant metal uptake. However, further experimental evidence is required, and wherefore we discuss different mechanisms of interaction of A. halleri with its rhizosphere microbiome that might have directly or indirectly affected plant metal accumulation. Deciphering the complex interactions between A. halleri and individual microbial taxa will help to further develop soil metal phytoextraction as an efficient and sustainable remediation strategy. PMID:25595759

  10. The effects of copper, manganese and zinc on plant growth and elemental accumulation in the manganese-hyperaccumulator Phytolacca americana.

    PubMed

    Zhao, Huijun; Wu, Liangqi; Chai, Tuanyao; Zhang, Yuxiu; Tan, Jinjuan; Ma, Shengwen

    2012-09-01

    Synchrotron radiation X-ray fluorescence (SRXRF) and inductively coupled plasma mass spectrometry were used to estimate major, minor and trace elements in Cu-, Zn- and Mn-treated Phytolacca americana. The effects of the addition of Cu, Zn and Mn on morphological parameters, such as root length, shoot height, and fresh and dry weights of shoots and roots, were also examined. In addition, the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidases (GPX) and catalase (CAT) and the expression of Fe-SOD, Cu/Zn-SOD, metallothionein-2 and glutathione S-transferase (GST) exposed to the highest amounts of Cu, Zn or Mn were detected. Our results confirmed the following: (1) Zn supplementation leads to chlorosis, disturbed elemental homeostasis and decreased concentrations of micro- and macroelements such as Fe, Mg, Mn, Ca and K. Cu competed with Fe, Mn and Zn uptake in plants supplemented with 25 μM Cu. However, no antagonistic interactions took place between Cu, Zn, Mn and Fe uptake in plants supplemented with 100 μM Cu. Mn supplementation at various concentrations had no negative effects on elemental deficits. Mn was co-located with high concentrations of Fe and Zn in mature leaves and the concentrations of macro elements were unchanged. (2) P. americana supplemented with increased concentrations of Zn and Cu exhibited lower biomass production and reduced plant growth. (3) When plants were supplemented with the highest Zn and Cu concentrations, symptoms of toxicity corresponded to decreased SOD or CAT activities and increased APX and GPX activities. However, Mn tolerance corresponded to increased SOD and CAT activities and decreased POD and APX activities. Our study revealed that heavy metals partially exert toxicity by disturbing the nutrient balance and modifying enzyme activities that induce damage in plants. However, P. americana has evolved hyper accumulating mechanisms to maintain elemental balance and redox homeostasis under excess Mn.

  11. Effect of fertilizers on Cd uptake of Amaranthus hypochondriacus, a high biomass, fast growing and easily cultivated potential Cd hyperaccumulator.

    PubMed

    Li, Ning Yu; Fu, Qing Lin; Zhuang, Ping; Guo, Bing; Zou, Bi; Li, Zhi An

    2012-02-01

    In a greenhouse pot experiment, we assessed the phytoextraction potential for Cd of three amaranth cultivars (Amaranthus hypochondriacus L. Cvs. K112, R104, and K472) and the effect of application of N, NP, and NPK fertilizer on Cd uptake of the three cultivars from soil contaminated with 5 mg kg(-1) Cd. All three amaranth cultivars had high levels of Cd concentration in their tissues, which ranged from 95.1 to 179.1 mg kg(-1) in leaves, 58.9 to 95.4 mg kg(-1) in stems, and 62.4 to 107.2 mg kg(-1) in roots, resulting in average bioaccumulation factors ranging from 17.7 to 29.7. Application of N, NP, or NPK fertilizers usually increased Cd content in leaves but decreased Cd content in stem and root. Fertilizers of N or NP combined did not substantially increase dry biomass of the 3 cultivars, leading to a limited increment of Cd accumulation. NPK fertilizer greatly increased dry biomass, by a factor of 2.7-3.8, resulting in a large increment of Cd accumulation. Amaranth cultivars (K112, R104, and K472) have great potential in phytoextraction of Cd contaminated soil. They have the merits of high Cd content in tissues, high biomass, easy cultivation and little effect on Cd uptake by fertilization.

  12. Arsenic-resistant proteobacterium from the phyllosphere of arsenic-hyperaccumulating fern (Pteris vittata L.) reduces arsenate to arsenite.

    PubMed

    Rathinasabapathi, Bala; Raman, Suresh Babu; Kertulis, Gina; Ma, Lena

    2006-07-01

    An arsenic-resistant bacterium, AsRB1, was isolated from the fronds of Pteris vittata grown in a site contaminated with copper chromium arsenate. The bacterium exhibited resistance to arsenate, arsenite, and antimony in the culture medium. AsRB1, like Pseudomonas putida, grew on MacConkey and xylose-lactose-desoxycholate agars and utilized citrate but, unlike P. putida, was positive for indole test and negative for oxidase test. A phylogenetic analysis of the 16S rRNA gene showed that AsRB1 is a proteobacterium of the beta subclass, related to Pseudomonas saccharophila and Variovorax paradoxus. Following an exogenous supply of arsenate, most arsenic occurred as arsenite in the medium and the cell extracts, suggesting reduction and extrusion of arsenic as the mechanism for arsenic resistance in AsRB1.

  13. Abnormal accumulation of trace metals by plants

    SciTech Connect

    Reeves, R.D.; Brooks, R.R.; Baker, A.J.M.

    1996-12-31

    The article describes the hyperaccumulation of metals by plants. Ranges for low, normal, high, and hyperaccumulating uptake are established. A partial list of hyperaccumulator species and their localities is included. Studies are reviewed and summarized for zinc, cadmium and lead, nickel, cobalt and copper, selenium, and cadmium and manganese hyperaccumulation.

  14. Monitoring of the heavy-metal hyperaccumulation in vegetal tissues by X-ray radiography and by femto-second laser induced breakdown spectroscopy.

    PubMed

    Kaiser, J; Samek, O; Reale, L; Liska, M; Malina, R; Ritucci, A; Poma, A; Tucci, A; Flora, F; Lai, A; Mancini, L; Tromba, G; Zanini, F; Faenov, A; Pikuz, T; Cinque, G

    2007-02-01

    This article reports on the utilization of X-ray microradiography and laser induced breakdown spectroscopy (LIBS) techniques for investigation of the metal accumulation in different part of leaf samples. The potential of the LIBS-analysis for finding the proper plant species for phytoremediation is compared with the results of microradiography measurements at the HERCULES source at ENEA, Rome (Italy) and X-ray microradiography experiments at the ELETTRA Synchrotron, Trieste (Italy).

  15. Phytoremediation of arsenic-contaminated groundwater using arsenic hyperaccumulator Pteris vittata L.: effects of frond harvesting regimes and arsenic levels in refill water.

    PubMed

    Natarajan, Seenivasan; Stamps, Robert H; Ma, Lena Q; Saha, Uttam K; Hernandez, Damaris; Cai, Yong; Zillioux, Edward J

    2011-01-30

    A large-scale hydroponic system to phytoremediate arsenic-contaminated groundwater using Pteris vittata (Chinese brake fern) was successfully tested in a field. In this 30-wk study, three frond-harvesting regimes (all, mature, and senescing fronds) and two water-refilling schemes to compensate for evapotranspiration (high-As water of 140-180 μg/L and low-As water of <7 μg/L) were investigated. Two experiments (Cycle 1 and Cycle 2) were conducted using the same plants in 24 tanks with each containing 600 L of arsenic-contaminated groundwater and 32 ferns. During Cycle 1 and with initial As of 140 μg/L, As in tanks refilled with low-As water was reduced to <10 μg/L in 8 wks compared to <10 μg/L in 17 wks in tanks refilled with high-As water. During Cycle 2 and with initial As of 180 μg/L, the remediation time was reduced by 2-5 wks, indicating that more established ferns were more efficient. In areas where clean water is limiting, refilling high-As water coupled with harvesting senescing fronds is recommended for more effective As phytoremediation.

  16. Identification and validation of heavy metal and radionuclide hyperaccumulating terrestrial plant species. Quarterly progress report, July 1, 1996--September 30, 1996

    SciTech Connect

    Kochian, L.

    1997-05-01

    Potential for phytoremediation of an aged radiocesium-contaminated soil from Brookhaven National Laboratory was investigated in three phases: (1) hydroponic screening for plant species capable of accumulating elevated levels of cesium in shoots, (2) amending contaminated soil to enhance {sup 137}Cs bioavailability, and (3) phytoextracting radiocesium with plant roots and its removal in harvested shoots. The bioaccumulation ratio of Cs in shoots of hydroponically grown plants ranged between 38 and 165. From solution, dicot species accumulated 2- to 4-fold more cesium in shoots than grasses. The effect of several chemical compounds on {sup 137}Cs desorption from the contaminated soil was investigated. Ammonium salts were the most effective at desorbing Cs from contaminated soil, but only 25% of radiocesium could be desorbed. Although release of radiocesium from the soil was concentration-dependent, this effect appeared to level off above 0.2 M ammonium in solution. In a pot study, from the soil contaminated with 400 pCi g{sup -1} soil, the greatest amount of {sup 137}Cs, 140 pCi, was removed in shoots of cabbage (Brassica oleracea var. capitata). {sup 137}Cs accumulation in shoots was significantly increased by the addition of 40 NH{sub 4}NO{sub 3} kg{sup -1} soil. Increasing NH{sub 4}NO{sub 3} application from 40 to 80 mmoles kg{sup -1} soil did not further increase radiocesium phytoextraction. The ability to accumulate radiocesium from soil in shoots was significantly different among species tested. This ability increased in order: reed Canary grass (Phalaris arundinacea) < Indian mustard (Brassica juncea) < tepary bean (Phaseolus acutifolius) < cabbage.

  17. Bioremediation of Cd-DDT co-contaminated soil using the Cd-hyperaccumulator Sedum alfredii and DDT-degrading microbes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of an integrated strategy for the remediation of soil co-contaminated by heavy metals and persistent organic pollutants is a major research priority for the decontamination of soil slated for use in agricultural production. The objective of this study was to develop a bioremediation ...

  18. Lead accumulation reduces photosynthesis in the lead hyper-accumulator Salvinia minima Baker by affecting the cell membrane and inducing stomatal closure.

    PubMed

    Leal-Alvarado, Daniel A; Espadas-Gil, Francisco; Sáenz-Carbonell, Luis; Talavera-May, Carlos; Santamaría, Jorge M

    2016-02-01

    Salvinia minima Baker accumulates a fair amount of lead in its tissues; however, no studies have investigated the effect of lead on the physiological processes that affect photosynthesis in this species. The objective of the present study was to assess whether the high amounts of lead accumulated by S. minima can affect its photosynthetic apparatus. The physiological changes in the roots and leaves in response to lead accumulation were analyzed. An exposure to 40 μM Pb(NO3)2 for 24 h (first stage) was sufficient to reduce the photosynthetic rate (Pn) by 44%. This reduction in Pn was apparently the result of processes at various levels, including damage to the cell membranes (mainly in roots). Interestingly, although the plants were transferred to fresh medium without lead for an additional 24 h (second stage), Pn not only remained low, but was reduced even further, which was apparently related to stomatal closure, and may have led to reduced CO2 availability. Therefore, it can be concluded that lead exposure first decreases the photosynthetic rate by damaging the root membrane and then induces stomatal closure, resulting in decreased CO2 availability.

  19. Identification and validation of heavy metal and radionuclide hyperaccumulating terrestrial plant species. Quarterly technical progress report, March 20, 1995--June 20, 1995

    SciTech Connect

    Kochian, L.

    1995-12-01

    The biological accumulation of heavy metals and cesium, strontium, and uranium in plants is discussed. The role of nutrient deficiencies and foliar treatments of manganese and iron compounds is described.

  20. Zn-bis-glutathionate is the best co-substrate of the monomeric phytochelatin synthase from the photosynthetic heavy metal-hyperaccumulator Euglena gracilis.

    PubMed

    García-García, Jorge D; Girard, Lourdes; Hernández, Georgina; Saavedra, Emma; Pardo, Juan P; Rodríguez-Zavala, José S; Encalada, Rusely; Reyes-Prieto, Adrián; Mendoza-Cózatl, David G; Moreno-Sánchez, Rafael

    2014-03-01

    The phytochelatin synthase from photosynthetic Euglena gracilis (EgPCS) was analyzed at the transcriptional, kinetic, functional, and phylogenetic levels. Recombinant EgPCS was a monomeric enzyme able to synthesize, in the presence of Zn(2+) or Cd(2+), phytochelatin2-phytochelatin4 (PC2-PC4) using GSH or S-methyl-GS (S-methyl-glutathione), but not γ-glutamylcysteine or PC2 as a substrate. Kinetic analysis of EgPCS firmly established a two-substrate reaction mechanism for PC2 synthesis with Km values of 14-22 mM for GSH and 1.6-2.5 μM for metal-bis-glutathionate (Me-GS2). EgPCS showed the highest Vmax and catalytic efficiency with Zn-(GS)2, and was inactivated by peroxides. The EgPCS N-terminal domain showed high similarity to that of other PCSases, in which the typical catalytic core (Cys-70, His-179 and Asp-197) was identified. In contrast, the C-terminal domain showed no similarity to other PCSases. An EgPCS mutant comprising only the N-terminal 235 amino acid residues was inactive, suggesting that the C-terminal domain is essential for activity/stability. EgPCS transcription in Euglena cells was not modified by Cd(2+), whereas its heterologous expression in ycf-1 yeast cells provided resistance to Cd(2+) stress. Phylogenetic analysis of the N-terminal domain showed that EgPCS is distant from plants and other photosynthetic organisms, suggesting that it evolved independently. Although EgPCS showed typical features of PCSases (constitutive expression; conserved N-terminal domain; kinetic mechanism), it also exhibited distinct characteristics such as preference for Zn-(GS)2 over Cd-(GS)2 as a co-substrate, a monomeric structure, and ability to solely synthesize short-chain PCs, which may be involved in conferring enhanced heavy-metal resistance.

  1. Classification of specialty seed meals from NIR reflectance spectra

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Near infrared reflectance spectroscopy was used to identify alternative seed meals proposed for food and feed formulations. Spectra were collected from cold pressed Camelina (Camelina sativa), Coriander (Coriandrum sativum), and Pennycress (Thlaspi arvense) meals. Additional spectra were collected ...

  2. Survey of alternative feedstocks for biodiesel production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Summarized will be results obtained from the production of biodiesel from several alternative feedstocks with promising agronomic characteristics. Such feedstocks include camelina (Camelina sativa L.), coriander (Coriandrum sativum L.), field pennycress (Thlaspi arvense L.), and meadowfoam (Limnanth...

  3. Biodiesel From Alternative Oilseed Feedstocks: Production and Properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fatty acid methyl esters were prepared and evaluated as potential biodiesel fuels from several alternative oilseed feedstocks, which included camelina (Camelina sativa L.), coriander (Coriandrum sativum L.), field mustard (Brassica juncea L.), field pennycress (Thlaspi arvense L.), and meadowfoam (L...

  4. Phytoremediation of Soil Trace Elements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytoremediation includes several distinct approaches to using plants to achieve soil remediation goals. Phytoextraction uses rare hyperaccumulator plants to accumulate in their shoots enough metals per year to achieve decontamination goals. Phytomining uses hyperaccumulators and biomass burn to pro...

  5. Collecting field pennycress germplasm in Colorado and characterization of oil and root variation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field pennycress (Thlaspi arvense) has been identified as a possible source of biodiesel that may perform better in colder climates than other biodiesel fuels. A germplasm collection of the species is being maintained by the U.S. Department of Agriculture for use in research, education, and crop imp...

  6. Trends in literature on new oilseed crops and related species: Seeking evidence of increasing or waning interest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bibliographic records on eight new crop species Camelina, Crambe, Cuphea, Physaria, Limnanthes, Stokesia, Thlaspi, and Vernonia from Agricola, CAB Abstracts, Scopus, and Web of Science were analyzed for historical and recent trends in the areas of research, author distribution, and quantity and impa...

  7. Advancements of pennycress as a biofuel and the synthesis of estolides thereof

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress (Thlaspi arvense L.) is being developed as an off-season rotation crop between annual corn and soybean production. This rotation scheme may offer distinct advantages to farmers by providing additional farm income from an otherwise fallow season with little impact on the subsequent soybean...

  8. Lubrication properties of new crop oils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oils from new crops such as lesquerella (Lesquerella fendleri), field pennycress (Thlaspi arvense L.), meadowfoam (Limnanthes alba L.), and cuphea PSR-23 (Cuphea viscosissima × Cuphea lanceolata) were investigated and compared with vegetable oils from commodity crops such as castor, corn, and soybea...

  9. Using fitness parameters to evaluate three oilseed Brassicaceae species as potential oil crops in two contrasting environments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thlaspi arvense and Camelina sativa have gained considerable attention as biofuel crops. But in some areas, these species, including C. microcarpa, are becoming rare weeds because of agriculture intensification. Including them as crops could guarantee their conservation in agricultural systems. The ...

  10. Field pennycress: A new oilseed crop for the production of biofuels, lubricants, and high-quality proteins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field pennycress (Thlaspi arvense L.) has numerous positive attributes that make it a very promising industrial oilseed crop. Its short growing season makes it suitable as an off-season crop between corn and soybean production in most of the upper Midwestern U.S. Fall planting of pennycress may also...

  11. Comparison of the emergence of three Brassicaceae species of different origins grown in Spain and USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thlaspi arvense, Camelina sativa, C. microcarpa and Neslia paniculata are four Brassicaceae family species that are becoming rare in North-Eastern Spain. Conversely, both T. arvense and C. sativa are being investigated as oilseed crops in North America for industrial/biofuel purposes. C. microcarpa ...

  12. Extraction of proteins from pennycress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress (Thlaspi arvense L.)has recently been found to have value as a source of biodiesel. Not only does it provide a high yield of quality oil, but perhaps more importantly, it can be planted after the harvest of traditional crops. It will grow through the winter (on days warmer than 0 C) and...

  13. Renewable Bio-Solar Hydrogen Production: The Second Generation (Part C)

    DTIC Science & Technology

    2014-11-28

    enzymes in the green alga Chlamydomonas reinhardtii, (b) increasing the levels of algal cellular starch , (c) understanding the mechanism of [FeFe... starch hyperaccumulation in Chlamydomonas reinhardtii, which can be used to make a variety of glucose based products. The Nannochloropsis genus of...Another significant advance was the generation of starch hyperaccumulating mutants. By overexpressing the isoamlyase gene in Chlamydomonas, central

  14. Arabis watsonii (P.H.Davis) F.K.Mey.: An overlooked cruciferous species from eastern Anatolia and its phylogenetic position

    PubMed Central

    Özüdoğru, Barış; Fırat, Mehmet

    2016-01-01

    Abstract Arabis watsonii (P.H.Davis) F.K.Mey. was initially reported as Thlaspi watsonii P.H.Davis in Flora of Turkey. Although F.K.Meyer transferred this species to Arabis L., this species has been overlooked and treated as Thlaspi L. in relevant literature for Flora of Turkey. In this study this species was evaluated using molecular (nuclear ITS and plastidic trnL-F sequences) and morphological data. Results clearly show that Arabis watsonii is sister to the Arabis hirsuta aggregate and its relatives. In conclusion, our results increased the number of known Arabis species in Turkey to 23. Furthermore, detailed description and distribution of the species are given and a new IUCN threat category for Arabis watsonii is proposed. PMID:28127244

  15. Heavy metal contamination from mining sites in South Morocco: 2. Assessment of metal accumulation and toxicity in plants.

    PubMed

    Boularbah, Ali; Schwartz, Christophe; Bitton, Gabriel; Aboudrar, Wafae; Ouhammou, Ahmed; Morel, Jean Louis

    2006-05-01

    Metalliferous soils cover a relatively large surface area in Morocco, and up to now no hyperaccumulating plants have been identified on these mining or these industrial sites. The aim of this work was to assess the extent of metal accumulation by plants found in three mining areas in southern Morocco with the ultimate goal of finding metal hyperaccumulating species by using the MetPAD biotest. The biotest helps to obtain information on the selective metal toxicity of aqueous extracts from the plants. A strong metal toxicity, as revealed by the biotest is an indication of a hyperaccumulating plant. Toxicity tests were run concurrently with chemicals analyses of metals in plants and their water extracts. The chemical analyses allow the determination of the hyperaccumulated metal(s). Specimens of the plant species mainly growing on and in the vicinity of the three mines were sampled with their corresponding soils. The results show that all plants analyzed had lower heavy metal content and toxicity despite the relatively very high soil concentrations. A comparison of our results with the criterion used to classify the hyperaccumulator plants indicates that plants we collected from mining sites were hypertolerant but not hyperaccumulators. This was confirmed by transfer factors generally lower than 1. Nevertheless, these tolerant plants species can be used as tools for revegetation for erosion control in metals-contaminated sites (phytostabilization).

  16. Copper and cobalt accumulation in plants: a critical assessment of the current state of knowledge.

    PubMed

    Lange, Bastien; van der Ent, Antony; Baker, Alan John Martin; Echevarria, Guillaume; Mahy, Grégory; Malaisse, François; Meerts, Pierre; Pourret, Olivier; Verbruggen, Nathalie; Faucon, Michel-Pierre

    2017-01-01

    This review synthesizes contemporary understanding of copper-cobalt (Cu-Co) tolerance and accumulation in plants. Accumulation of foliar Cu and Co to > 300 μg g(-1) is exceptionally rare globally, and known principally from the Copperbelt of Central Africa. Cobalt accumulation is also observed in a limited number of nickel (Ni) hyperaccumulator plants occurring on ultramafic soils around the world. None of the putative Cu or Co hyperaccumulator plants appears to comply with the fundamental principle of hyperaccumulation, as foliar Cu-Co accumulation is strongly dose-dependent. Abnormally high plant tissue Cu concentrations occur only when plants are exposed to high soil Cu with a low root to shoot translocation factor. Most Cu-tolerant plants are Excluders sensu Baker and therefore setting nominal threshold values for Cu hyperaccumulation is not informative. Abnormal accumulation of Co occurs under similar circumstances in the Copperbelt of Central Africa as well as sporadically in Ni hyperaccumulator plants on ultramafic soils; however, Co-tolerant plants behave physiologically as Indicators sensu Baker. Practical application of Cu-Co accumulator plants in phytomining is limited due to their dose-dependent accumulation characteristics, although for Co field trials may be warranted on highly Co-contaminated mineral wastes because of its relatively high metal value.

  17. Classification and identification of metal-accumulating plant species by cluster analysis.

    PubMed

    Yang, Wenhao; Li, He; Zhang, Taoxiang; Sen, Lin; Ni, Wuzhong

    2014-09-01

    Identification and classification of metal-accumulating plant species is essential for phytoextraction. Cluster analysis is used for classifying individuals based on measured characteristics. In this study, classification of plant species for metal accumulation was conducted using cluster analysis based on a practical survey. Forty plant samples belonging to 21 species were collected from an ancient silver-mining site. Five groups such as hyperaccumulator, potential hyperaccumulator, accumulator, potential accumulator, and normal accumulating plant were graded. For Cd accumulation, the ancient silver-mining ecotype of Sedum alfredii was treated as a Cd hyperaccumulator, and the others were normal Cd-accumulating plants. For Zn accumulation, S. alfredii was considered as a potential Zn hyperaccumulator, Conyza canadensis and Artemisia lavandulaefolia were Zn accumulators, and the others were normal Zn-accumulating plants. For Pb accumulation, S. alfredii and Elatostema lineolatum were potential Pb hyperaccumulators, Rubus hunanensis, Ajuga decumbens, and Erigeron annuus were Pb accumulators, C. canadensis and A. lavandulaefolia were potential Pb accumulators, and the others were normal Pb-accumulating plants. Plant species with the potential for phytoextraction were identified such as S. alfredii for Cd and Zn, C. canadensis and A. lavandulaefolia for Zn and Pb, and E. lineolatum, R. hunanensis, A. decumbens, and E. annuus for Pb. Cluster analysis is effective in the classification of plant species for metal accumulation and identification of potential species for phytoextraction.

  18. Regulation of gemma formation in the copper moss Scopelophila cataractae by environmental copper concentrations.

    PubMed

    Nomura, Toshihisa; Hasezawa, Seiichiro

    2011-09-01

    Considerable attention has recently been focused on the use of hyperaccumulator plants for the phytoremediation of soils contaminated with heavy metals. The moss, Scopelophila cataractae (Mitt.) Broth., is a typical hyperaccumulator that is usually observed only in copper-rich environments and which accumulates high concentrations of copper in its tissues. However, many of the physiological processes and mechanisms for metal hyperaccumulation in S. cataractae remain unknown. To address this issue, we examined the mechanisms regulating gemma formation, which is considered the main strategy by which S. cataractae relocates to new copper-rich areas. From this study we found that treatment of S. cataractae with high concentrations of copper suppressed gemma formation but promoted protonemal growth. The suppressive effect was not observed by treatment with heavy metals other than copper. These results suggest the importance of copper-sensitive asexual reproduction in the unique life strategy of the copper moss, S. cataractae.

  19. The potential for heavy metal decontamination

    SciTech Connect

    Baker, A.J.M.; McGrath, S.P.; Sidoli, C.M.D.; Reeves, R.D.

    1996-12-31

    Preliminary trials to assess the ability of plant species to extract metals are presented. A range of zinc and nickel hyperaccumulator plants from the Brassicaceae family, collected from diverse populations in Europe, were grown on plots along with nonaccumulating crop plants from the same family. Extraction efficiencies and the number of croppings required to reduce the total zinc in the soil to a concentration of 300 mg/kg are tabulated. Zinc accumulation remained high over a wide range of soil metal concentration. However, the concentration of nickel in the hyperaccumulators increased in accordance with increasing total nickel concentrations in the soil. Calculations suggest that there is an excellent potential for using hyperaccumulator species to remove metals from the rhizosphere where remediation can be considered over a period of years and multiple cropping is a viable option.

  20. Replication and encapsidation of the viroid-like satellite RNA of lucerne transient streak virus are supported in divergent hosts by cocksfoot mottle virus and turnip rosette virus.

    PubMed

    Sehgal, O P; Sinha, R C; Gellatly, D L; Ivanov, I; AbouHaidar, M G

    1993-04-01

    Cocksfoot mottle sobemovirus supports replication and encapsidation of the viroid-like satellite RNA (sat-RNA) of lucerne transient streak virus (LTSV) in two monocotyledonous species, Triticum aestivum and Dactylis glomerata. Additionally, LTSV sat-RNA replicates effectively in the presence of turnip rosette sobemovirus in Brassica rapa, Raphanus raphanistrum and Sinapsis arvensis, but not in Thlaspi arvense or Nicotiana bigelovii, indicating that host species markedly influence this interaction. Previous reports of the association between LTSV sat-RNA and helper sobemoviruses were limited to dicotyledonous hosts. Our results demonstrate that the biological interaction between these two entities spans divergent dicotyledonous and monocotyledonous species.

  1. Pint-sized plants pack a punch in fight against heavy metals

    SciTech Connect

    Boyd, V.

    1996-05-01

    USDA researchers are experimenting with plants that naturally scavenge heavy metals such as cadmium and zinc from the soil. Known as hyperaccumulators, the plants can store up to 2.5% of their dry weight in heavy metals in leaves without yield reductions. They can be grown, harvested, and dried. The dried material is then burned, and the metal ore can be recovered. As well as discussing the history of hyperaccumulators, this article focuses on the plant pennycress and work on improving its metal uptake.

  2. Histidine promotes the loading of nickel and zinc, but not of cadmium, into the xylem in Noccaea caerulescens.

    PubMed

    Kozhevnikova, Anna D; Seregin, Ilya V; Verweij, Rudo; Schat, Henk

    2014-01-01

    Histidine is known to be involved in Ni hyperaccumulation. Recently, histidine-dependent xylem loading of Ni and Zn has been demonstrated in the Zn/Ni/Cd hyperaccumulator, Noccaea caerulescens. Here we tested the hypothesis whether Cd xylem loading is histidine-dependent, too. In contrast to that of Ni and Zn, the xylem loading of Cd was not affected by exogenous histidine. Histidine accumulation in root cells appears to facilitate the radial transport of Ni and Zn, but not Cd, across the roots. This may be due to the relatively high preference of Cd for coordination with sulfur over coordination with nitrogen, in comparison with Ni and Zn.

  3. Root-Secreted Nicotianamine from Arabidopsis halleri Facilitates Zinc Hypertolerance by Regulating Zinc Bioavailability1[W][OPEN

    PubMed Central

    Tsednee, Munkhtsetseg; Yang, Shun-Chung; Lee, Der-Chuen; Yeh, Kuo-Chen

    2014-01-01

    Hyperaccumulators tolerate and accumulate extraordinarily high concentrations of heavy metals. Content of the metal chelator nicotianamine (NA) in the root of zinc hyperaccumulator Arabidopsis halleri is elevated compared with nonhyperaccumulators, a trait that is considered to be one of the markers of a hyperaccumulator. Using metabolite-profiling analysis of root secretions, we found that excess zinc treatment induced secretion of NA in A. halleri roots compared with the nonhyperaccumulator Arabidopsis thaliana. Metal speciation analysis further revealed that the secreted NA forms a stable complex with Zn(II). Supplying NA to a nonhyperaccumulator species markedly increased plant zinc tolerance by decreasing zinc uptake. Therefore, NA secretion from A. halleri roots facilitates zinc hypertolerance through forming a Zn(II)-NA complex outside the roots to achieve a coordinated zinc uptake rate into roots. Secretion of NA was also found to be responsible for the maintenance of iron homeostasis under excess zinc. Together our results reveal root-secretion mechanisms associated with hypertolerance and hyperaccumulation. PMID:25118254

  4. Xylem exudate composition and root-to-shoot nickel translocation in Alyssum species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An improved understanding of Ni root-to-shoot translocation mechanism in hyperaccumulators is necessary to increase Ni uptake efficiency for phytoextraction technologies. It is presumed that an important aspect of Ni translocation and storage involves chelation with organic ligands. It has been re...

  5. Chelator-buffered nutrient solution is ineffective in extracting Ni from seeds of Alyssum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hyperaccumulator species of the genera Alyssum can accumulate 100 times more Ni than normal crops and are therefore used for phytomining and phytoextraction of nickel contaminated soils. Basic studies on the physiology and metal uptake mechanisms of these plants are needed to increase efficiency and...

  6. The fascinating facets of plant selenium accumulation - biochemistry, physiology, evolution and ecology.

    PubMed

    Schiavon, Michela; Pilon-Smits, Elizabeth A H

    2017-03-01

    Contents 1582 I. 1582 II. 1583 III. 1588 IV. 1590 V. 1592 1592 References 1592 SUMMARY: The importance of selenium (Se) for medicine, industry and the environment is increasingly apparent. Se is essential for many species, including humans, but toxic at elevated concentrations. Plant Se accumulation and volatilization may be applied in crop biofortification and phytoremediation. Topics covered here include beneficial and toxic effects of Se on plants, mechanisms of Se accumulation and tolerance in plants and algae, Se hyperaccumulation, and ecological and evolutionary aspects of these processes. Plant species differ in the concentration and forms of Se accumulated, Se partitioning at the whole-plant and tissue levels, and the capacity to distinguish Se from sulfur. Mechanisms of Se hyperaccumulation and its adaptive significance appear to involve constitutive up-regulation of sulfate/selenate uptake and assimilation, associated with elevated concentrations of defense-related hormones. Hyperaccumulation has evolved independently in at least three plant families, probably as an elemental defense mechanism and perhaps mediating elemental allelopathy. Elevated plant Se protects plants from generalist herbivores and pathogens, but also gives rise to the evolution of Se-resistant specialists. Plant Se accumulation affects ecological interactions with herbivores, pollinators, neighboring plants, and microbes. Hyperaccumulation tends to negatively affect Se-sensitive ecological partners while facilitating Se-resistant partners, potentially affecting species composition and Se cycling in seleniferous ecosystems.

  7. Cadmium accumulation characteristics of the winter farmland weeds Cardamine hirsuta Linn. and Gnaphalium affine D. Don.

    PubMed

    Lin, Lijin; Shi, Jun; Liu, Qihua; Liao, Ming'an; Mei, Luoyin

    2014-07-01

    In a preliminary study, we found that the cadmium (Cd) concentrations in shoots of the winter farmland weeds Cardamine hirsuta Linn. and Gnaphalium affine D. Don exceeded the critical value of a Cd-hyperaccumulator (100 mg kg(-1)), indicating that these two farmland weeds might be Cd-hyperaccumulators. In this study, we grew these species in soil containing various concentrations of Cd to further evaluate their Cd accumulation characteristics. The biomasses of C. hirsuta and G. affine decreased with increasing Cd concentrations in the soil, while the root/shoot ratio and the Cd concentrations in shoot tissues increased. The Cd concentrations in shoots of C. hirsuta and G. affine reached 121.96 and 143.91 mg kg(-1), respectively, at the soil Cd concentration of 50 mg kg(-1). Both of these concentrations exceeded the critical value of a Cd-hyperaccumulator (100 mg kg(-1)). The shoot bioconcentration factors of C. hirsuta and G. affine were greater than 1. The translocation factor of C. hirsuta was less than 1 and that of G. affine was greater than 1. These findings indicated that C. hirsuta is a Cd-accumulator and G. affine is Cd-hyperaccumulator. Both plants are distributed widely in the field, and they could be used to remediate Cd-contaminated farmland soil in winter.

  8. What about the rare-earth elements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is insufficient understanding of the nutritional physiology of pecan trees and orchards; thus, affecting nutmeat yield and quality, disease resistance and alternate bearing. An analysis of the rare-earth element composition of pecan and related hickory cousins found that they hyperaccumulate ...

  9. Expression of an "Arabidopsis" Ca(2+)/H(+) antiporter CAX1 variant in petunia enhances cadmium tolerance and accumulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytoremediation is a cost-effective and minimally invasive technology to cleanse soils contaminated with heavy metals. However, few plant species are suitable for phytoremediation of metals such as cadmium (Cd). Genetic engineering offers a powerful tool to generate plants that can hyperaccumulate ...

  10. Effects of Cadmium on Nickel Tolerance and Accumulation in Alyssum species and Cabbage Grown in Nutrient Solution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nickel phytoextraction using hyperaccumulator plant species to accumulate Ni from mineralized and contaminated soils rich in Ni is an emerging technology. Serpentinite derived soils which contain Ni ore value have a very low ratio of Ca:Mg among soils due the nature of the parent rock. In crop plant...

  11. The Engineered Phytoremediation of Ionic and Methylmercury Pollution

    SciTech Connect

    Richard Meagher; Sarah Marshburn; Andrew Heaton; Anne Marie Zimer; Raoufa Rahman

    2003-06-24

    Our current specific objectives are to use transgenic plants to control the chemical species, electrochemical state, and above ground binding of mercury to (a) prevent methylmercury from entering the food-chain, (b) remove mercury from polluted sites, and (c) hyperaccumulate mercury in above ground tissues for later harvest.

  12. Metal-accumulating plants: The biological resource and its commercial exploitation is soil clean-up technology

    SciTech Connect

    Baker, A.J.M.; Reeves, R.D.

    1996-12-31

    This presentation provides a broad overview of metal hyperaccumulator plants and biological accumulation technology. Plants that have been identified as having the greatest potentials for development as phytoremediator crops for metal-contaminated soils are very briefly discussed. Phytoextraction, rhizofiltration, and phytostabilization are briefly defined. Issues pertinent to large scale phytoremediation of soils are discussed, including biological and technological constraints.

  13. SYNCHROTRON X-RAY ABSORPTION-EDGE COMPUTED MICROTOMOGRAPHY IMAGING OF THALLIUM COMPARTMENTALIZATION IN IBERIS INTERMEDIA

    EPA Science Inventory

    Thallium (TI) is an extremely toxic metal which, due to its similarities to K, is readily taken up by plants. Thallium is efficiently hyperaccumulated in Iberis intermedia as TI(I). Distribution and compartmentalization of TI in I. intermedia is highes...

  14. Current status and challenges in developing Ni phytomining: An agronomic perspective

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This review examines the current status, progress and challenges in Ni phytomining agronomy undertaken since the first field trial two decades ago. To date, over 400 Ni hyperaccumulators have been documented (of which >30% are in Cuba) including approximately 50 species with potential for use in Ni ...

  15. NiO (bunsenite) is not available to Alyssum species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some species of the genus Alyssum are capable of accumulating up to 30 g kg-1 DW Ni in their leaves when grown on serpentine soils where these species are endemic. The unique ability of Alyssum species to hyperaccumulate high concentration of Ni stimulated basic research toward a better understandi...

  16. NiO(s) (Bunsenite) is not Available to Alyssum species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    AIMS: To determine if the Ni-hyperaccumulator Alyssum corsicum can absorb Ni from the kinetically inert crystalline mineral NiO(s) (bunsenite). METHODS: A. corsicum and A. montanum plants were grown for 30 days in a serpentine Hoagland solution. NiO was provided at 0 or 0.1 g L-1 (1.34 mmol L-1) ...

  17. Identification of a novel pathway involving a GATA transcription factor in yeast and possibly plant Zn uptake and homeostasis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To gain a better understanding of the regulation of Zn homeostasis in plants and the degree of conservation of Zn homeostasis between plants and yeast, a cDNA library from the Zn/Cd hyperaccumulating plant species, Nocceae caerulescens, was screened for its ability to restore growth under Zn limitin...

  18. Phytoremediative urban design: transforming a derelict and polluted harbour area into a green and productive neighbourhood.

    PubMed

    Wilschut, M; Theuws, P A W; Duchhart, I

    2013-12-01

    Many urban areas are polluted by industrial activities and waste disposal in landfills. Since conventional soil remediation techniques are costly and unsustainable, phytoremediation might offer an alternative. In this article, we explore how phytoremediation can be integrated into the transformation of urban post-industrial areas, while improving public space. Buiksloterham, a polluted and deprived industrial area in Amsterdam, serves as case study. Buiksloterham is polluted with heavy metals, with Zinc (Zn) concentrations being the highest. A regression-model for Alpine Pennycress (Thlaspi caerulescens) is used to estimate the time needed to remediate the site. This reveals a conflict in time between remediation and urban development. A research by design experiment shows how to overcome this conflict by dealing with polluted soil innovatively while emphasizing spatial and aesthetic qualities of the phytoremediation plant species. The resulting landscape framework integrates phytoremediation with biomass production and gives new ecological, economic and social value to Buiksloterham.

  19. Fanweed toxicosis in cattle: case history, analytical method, suggested treatment, and fanweed detoxification.

    PubMed

    Smith, R A; Crowe, S P

    1987-04-01

    Two hundred and twenty head of pregnant cows were fed virtually 100% fanweed (Thlaspi arvense) in November 1984. One hundred became distressed and colicy within 4 hr of feeding. Eight died over the next 5 days despite removal of the feed and symptomatic treatment. Necropsy revealed massive submucosal edema of the wall of the forestomachs, particularly the rumen. Four abortions occurred. The feed was analyzed and was found to liberate 250 mg/100g of AITC. Possible methods of treatment were devised in case the problem should recur. Fanweed contains sinigrin and the enzyme myrosin. When the plant is crushed and moistened, allylisothiocyanate (AITC) is formed along with glucose and potassium acid sulfate. Application of Le Chatelier's principle led to an investigation of the effect of pH on in vitro generation of AITC. Methods of destroying AITC were also examined, and detoxification studies were undertaken on fanweed.

  20. Phytoremediation of ionic and methylmercury pollution

    SciTech Connect

    Meagher, Richard B

    2010-04-28

    Our long-term goal is to enable highly productive plant species to extract, resist, detoxify, and sequester the toxic elemental pollutants, like the heavy metal mercury. Our current working hypothesis is that transgenic plants controlling the transport, chemical speciation, electrochemical state. volatilization, and aboveground binding of mercury will: a) tolerate mercury and grow rapidly in mercury contaminated environments; b) prevent methylmercury from entering the food chain; c) remove mercury from polluted soil and . water; and d) hyperaccumulate mercury in aboveground tissues for later harvest. Progress toward these specific aims is reported: to increase the transport of mercury into roots and to aboveground vegetative organs; to increase biochemical sinks and storage for mercury in leaves; to increase leaf cell vacuolar storage of mercury; and to demonstrate that several stacked transgenes, when functioning in concert, enhance mercury resistance and hyperaccumulation to high levels.

  1. The relationship of selenium tolerance and speciation in Lecythidaceae species.

    PubMed

    Németh, Anikó; García Reyes, Juan Francisco; Kosáry, Judit; Dernovics, Mihály

    2013-12-01

    Comparative study of selenium (Se) speciation in hyperaccumulator plants offers an interesting challenge from the analytical point of view. In our study the application of a sophisticated sample clean-up procedure and the combination of elemental and molecular mass spectrometric methods led to the identification of several new selenocompounds. The difference between the Se speciation of the primary accumulator Lecythis minor and the secondary accumulator Bertholletia excelsa confirmed the current opinion that the speciation pattern in hyperaccumulator plants is principally related to the mechanism of accumulation and not to taxonomy. The most abundant new selenocompounds were found to be the derivatives of selenohomocysteine (SeHCy) and selenomethionine (SeMet), including fatty acid metabolism related compounds. A series of SeHCy derived species containing multiple Se atoms (>2) was also detected and their structures were validated by the synthesis of their S-Se analogues.

  2. Impact of heavy metal toxicity and constructed wetland system as a tool in remediation.

    PubMed

    Usharani, B; Vasudevan, N

    2016-01-01

    The objective of this review is to throw light upon the global concern of heavy metal-contaminated sites and their remediation through an ecofriendly approach. Accumulated heavy metals in soil and water bodies gain entry through the food chain and pose serious threat to all forms of life. This has engendered interest in phytoremediation techniques where hyperaccumulators are used. Constructed wetland has a pivotal role and is a cost-effective technique in the remediation of heavy metals. Metal availability and mobility are influenced by the addition of chelating agents, which enhance the availability of metal uptake. This review helps in identifying the critical knowledge gaps and areas to enhance research in the future to develop strategies such as genetically engineered hyperaccumulators to attain an environment devoid of heavy metal contamination.

  3. Enhancement of Phosphate Absorption by Garden Plants by Genetic Engineering: A New Tool for Phytoremediation

    PubMed Central

    Togami, Junichi; Mason, John G.; Chandler, Stephen F.; Tanaka, Yoshikazu

    2013-01-01

    Although phosphorus is an essential factor for proper plant growth in natural environments, an excess of phosphate in water sources causes serious pollution. In this paper we describe transgenic plants which hyperaccumulate inorganic phosphate (Pi) and which may be used to reduce environmental water pollution by phytoremediation. AtPHR1, a transcription factor for a key regulator of the Pi starvation response in Arabidopsis thaliana, was overexpressed in the ornamental garden plants Torenia, Petunia, and Verbena. The transgenic plants showed hyperaccumulation of Pi in leaves and accelerated Pi absorption rates from hydroponic solutions. Large-scale hydroponic experiments indicated that the enhanced ability to absorb Pi in transgenic torenia (AtPHR1) was comparable to water hyacinth a plant that though is used for phytoremediation causes overgrowth problems. PMID:23984322

  4. Comments on "Determination of mercury, cadmium, lead, zinc, selenium and iron by ICP-OES in mushroom samples from around thermal power plant in Muğla, Turkey". doi:10.1007/s00128-011-0357-1.

    PubMed

    Falandysz, Jerzy

    2012-05-01

    In several articles on trace elements in mushrooms erroneous data were published on minerals sequestered in fruiting bodies. The biased analytical data published gave a false picture on the composition and nutritional value of mushrooms with respect to minerals. Wild mushrooms are relatively rich in trace elements and some species can hyperaccumulate certain metals. Selenium as reported in the referenced article is discussed in light of typical Se concentrations determined using validated methods as reported by other authors.

  5. EDTA-assisted Pb phytoextraction.

    PubMed

    Saifullah; Meers, E; Qadir, M; de Caritat, P; Tack, F M G; Du Laing, G; Zia, M H

    2009-03-01

    Pb is one of the most widespread and metal pollutants in soil. It is generally concentrated in surface layers with only a minor portion of the total metal found in soil solution. Phytoextraction has been proposed as an inexpensive, sustainable, in situ plant-based technology that makes use of natural hyperaccumulators as well as high biomass producing crops to help rehabilitate soils contaminated with heavy metals without destructive effects on soil properties. The success of phytoextraction is determined by the amount of biomass, concentration of heavy metals in plant, and bioavailable fraction of heavy metals in the rooting medium. In general, metal hyperaccumulators are low biomass, slow growing plant species that are highly metal specific. For some metals such as Pb, there are no hyperaccumulator plant species known to date. Although high biomass-yielding non-hyperaccumulator plants lack an inherent ability to accumulate unusual concentrations of Pb, soil application of chelating agents such as EDTA has been proposed to enhance the metal concentration in above-ground harvestable plant parts through enhancing the metal solubility and translocation from roots to shoots. Leaching of metals due to enhanced mobility during EDTA-assisted phytoextraction has been demonstrated as one of the potential hazards associated with this technology. Due to environmental persistence of EDTA in combination with its strong chelating abilities, the scientific community is moving away from the use of EDTA in phytoextraction and is turning to less aggressive alternative strategies such as the use of organic acids or more degradable APCAs (aminopolycarboxylic acids). We have therefore arrived at a point in phytoremediation research history in which we need to distance ourselves from EDTA as a proposed soil amendment within the context of phytoextraction. However, valuable lessons are to be learned from over a decade of EDTA-assisted phytoremediation research when considering the

  6. Molecular cloning and characterization of a phytochelatin synthase gene, PvPCS1, from Pteris vittata L.

    PubMed

    Dong, Ruibin; Formentin, Elide; Losseso, Carmen; Carimi, Francesco; Benedetti, Piero; Terzi, Mario; Schiavo, Fiorella Lo

    2005-12-01

    Pteris vittata L. is a staggeringly efficient arsenic hyperaccumulator that has been shown to be capable of accumulating up to 23,000 microg arsenic g(-1), and thus represents a species that may fully exploit the adaptive potential of plants to toxic metals. However, the molecular mechanisms of adaptation to toxic metal tolerance and hyperaccumulation remain unknown, and P. vittata genes related to metal detoxification have not yet been identified. Here, we report the isolation of a full-length cDNA sequence encoding a phytochelatin synthase (PCS) from P. vittata. The cDNA, designated PvPCS1, predicts a protein of 512 amino acids with a molecular weight of 56.9 kDa. Homology analysis of the PvPCS1 nucleotide sequence revealed that it has low identity with most known plant PCS genes except AyPCS1, and the homology is largely confined to two highly conserved regions near the 5'-end, where the similarity is as high as 85-95%. The amino acid sequence of PvPCS1 contains two Cys-Cys motifs and 12 single Cys, only 4 of which (Cys-56, Cys-90/91, and Cys-109) in the N-terminal half of the protein are conserved in other known PCS polypeptides. When expressed in Saccharomyces cerevisae, PvPCS1 mediated increased Cd tolerance. Cloning of the PCS gene from an arsenic hyperaccumulator may provide information that will help further our understanding of the genetic basis underlying toxic metal tolerance and hyperaccumulation.

  7. Shining light on metals in the environment

    SciTech Connect

    McNear, Jr., D.H.; Tappero, R.; Sparks, D.L.

    2010-07-20

    Elucidating the speciation of heavy metals in the environment is paramount to understanding their potential mobility and bioavailability. Cutting-edge synchrotron-based techniques such as microfocused X-ray absorption fine-structure (XAFS) and X-ray fluorescence (XRF) spectroscopy and microtomography have revolutionized the way metal reactions and processes in natural systems are studied. In this article, we apply these intense-light tools to decipher metal forms (species) and associations in contaminated soils and metal-hyperaccumulating plants.

  8. Use of synchrotron radiation to characterize metals in plants: the case of Cd in the hyperacumulator Arabidopsis halleri

    NASA Astrophysics Data System (ADS)

    Isaure, M.; Sarret, G.; Verbruggen, N.

    2010-12-01

    Phytoremediation uses plants to extract (phytoextraction) or stabilize (phytostabilization) metals accumulated in soils, and can be an alternative to invasive physico-chemical remediation techniques. Its development requires the knowledge of the mechanisms involved in metal tolerance and accumulation in plants, and particularly the way that plants transfer and store metals. In that context, synchrotron radiation based techniques such as micro-focused X-Ray Fluorescence (µXRF), and micro-focused X-ray Absorption Spectroscopy, including Extended X-ray Absorption Fine Structure and X-ray Absorption Near Edge Structure, are particularly suited to determine the localization and the chemical forms of metals in the different tissues, cells and sub-cellular compartments. Arabidopsis halleri is a Zn, Cd hyperaccumulating plant, naturally growing on contaminated sites, and is a model plant to investigate metal hyperaccumulation. This work presents the application of µXRF and Cd µXANES to determine the distribution and speciation of Cd in this species. Results showed that Cd was mainly located in the mesophyll and veins of leaves. It is bound to S ligands in some leaves and to O/N ligands in other ones, and the observed variations may be related to the age of the leaves. Cd speciation seems to differ from other metals, and particularly Zn, generally encountered in hyperaccumulators. High local Cd concentrations were also detected at the base of trichomes, epidermal hairs of leaves, associated to O/N ligands, probably to the cell wall. This phenomenon was also observed on non-hyperaccumulators and is clearly not the major sink for Cd, but trichomes might play a role in the detoxification process. This study illustrates the suitability of synchrotron radiation based techniques to investigate metal distribution and speciation in plants.

  9. Cadmium Accumulation Characteristics in Turnip Landraces from China and Assessment of Their Phytoremediation Potential for Contaminated Soils

    PubMed Central

    Li, Xiong; Zhang, Xiaoming; Yang, Ya; Li, Boqun; Wu, Yuansheng; Sun, Hang; Yang, Yongping

    2016-01-01

    Heavy metal (HM) pollution is a global environmental problem that threatens ecosystem and human health. Cadmium (Cd) pollution is the most prominent HM pollution type because of its high toxicity, strong migration, and the large polluted area globally. Phytoremediation of contaminated soil is frequently practiced because of its cost-effectiveness and operability and because it has no associated secondary pollution. High-accumulation plants, including those identified as hyperaccumulators, play an important role in phytoremediation. Therefore, screening of plants to identify hyperaccumulators is important for continued phytoremediation. In the present study, we investigated the Cd tolerance and accumulation capabilities of 18 turnip landraces from China under a soil experiment with known Cd level. The results indicated that turnip has a high capacity for Cd accumulation. Furthermore, significant differences in Cd tolerance and accumulation characteristics were found among different landraces when they grew at 50 mg kg-1 (dry weight) Cd concentration. Among the studied landraces, five turnip landraces met the requirements of Cd hyperaccumulators and three landraces were identified as potential candidates. However, the total Cd content accumulated by individual plant of different turnip landraces was dependent on both the Cd accumulation capacity and plant biomass. Compared with some reported Cd hyperaccumulators, turnip not only shows a high Cd-accumulation capacity but also has rapid growth and a wide distribution area. These advantages indicate that turnip may have considerable potential for phytoremediation of Cd-contaminated soil. Furthermore, the study also indicates that it is not advisable to consume turnip cultivated in an environment that exceeds safe Cd levels. PMID:28018398

  10. Analysis of Sulfur And Selenium Assimilation in 'Astragalus' Plants With Varying Capacities to Accumulate Selenium

    SciTech Connect

    Sors, T.G.; Ellis, D.R.; Na, G.Nam.; Lahner, B.; Lee, S.; Leustek, T.; Pickering, I.J.; Salt, D.E.; /Purdue U. /Rutgers U., Piscataway /Saskatchewan U.

    2007-08-08

    Several Astragalus species have the ability to hyperaccumulate selenium (Se) when growing in their native habitat. Given that the biochemical properties of Se parallel those of sulfur (S), we examined the activity of key S assimilatory enzymes ATP sulfurylase (ATPS), APS reductase (APR), and serine acetyltransferase (SAT), as well as selenocysteine methyltransferase (SMT), in eight Astragalus species with varying abilities to accumulate Se. Se hyperaccumulation was found to positively correlate with shoot accumulation of S-methylcysteine (MeCys) and Se-methylselenocysteine (MeSeCys), in addition to the level of SMT enzymatic activity. However, no correlation was observed between Se hyperaccumulation and ATPS, APR, and SAT activities in shoot tissue. Transgenic Arabidopsis thaliana overexpressing both ATPS and APR had a significant enhancement of selenate reduction as a proportion of total Se, whereas SAT overexpression resulted in only a slight increase in selenate reduction to organic forms. In general, total Se accumulation in shoots was lower in the transgenic plants overexpressing ATPS, PaAPR, and SAT. Root growth was adversely affected by selenate treatment in both ATPS and SAT overexpressors and less so in the PaAPR transgenic plants. Such observations support our conclusions that ATPS and APR are major contributors of selenate reduction in planta. However, Se hyperaccumulation in Astragalus is not driven by an overall increase in the capacity of these enzymes, but rather by either an increased Se flux through the S assimilatory pathway, generated by the biosynthesis of the sink metabolites MeCys or MeSeCys, or through an as yet unidentified Se assimilation pathway.

  11. The potential of Thelypteris palustris and Asparagus sprengeri in phytoremediation of arsenic contamination.

    PubMed

    Anderson, LaShunda L; Walsh, Maud; Roy, Amitava; Bianchetti, Christopher M; Merchan, Gregory

    2011-02-01

    The potential of two plants, Thelypteris palustris (marsh fern) and Asparagus sprengeri (asparagus fern), for phytoremediation of arsenic contamination was evaluated. The plants were chosen for this study because of the discovery of the arsenic hyperaccumulating fern, Pteris vittata (Ma et al., 2001) and previous research indicating asparagus fern's ability to tolerate > 1200 ppm soil arsenic. Objectives were (1) to assess if selected plants are arsenic hyperaccumulators; and (2) to assess changes in the species of arsenic upon accumulation in selected plants. Greenhouse hydroponic experiments arsenic treatment levels were established by adding potassium arsenate to solution. All plants were placed into the hydroponic experiments while still potted in their growth media. Marsh fern and Asparagus fern can both accumulate arsenic. Marsh fern bioaccumulation factors (> 10) are in the range of known hyperaccumulator, Pteris vittata Therefore, Thelypteris palustris is may be a good candidate for remediation of arsenic soil contamination levels of < or = 500 microg/L arsenic. Total oxidation of As (III) to As (V) does not occur in asparagus fern. The asparagus fern is arsenic tolerant (bioaccumulation factors < 10), but is not considered a good potential phytoremediation candidate.

  12. A newly found cadmium accumulator--Malva sinensis Cavan.

    PubMed

    Zhang, Shirong; Chen, Mingying; Li, Ting; Xu, Xiaoxun; Deng, Liangji

    2010-01-15

    Screening hyperaccumulators and accumulators is a key step in the phytoremediation of soils contaminated by heavy metals. A pot experiment was conducted involving a soil Cd concentration gradient (0, 50, 75, 100, 125, 150, 175, and 200 mg kg(-1)) to determine if Malva sinensis Cavan. from two lead-zinc mines in Kangding and Yajiang in western Sichuan, China, is a Cd-hyperaccumulator. The highest Cd concentrations in plant shoots from Kangding and Yajiang were 154.30 and 122.77 mg kg(-1), respectively, at a soil Cd concentration of 200 mg kg(-1). The largest amounts of accumulation in plant shoots from Kangding and Yajiang were 700.5 and 1403.2 microg pot(-1), respectively. The bioconcentration factors in shoots were 0.53-1.03 for Kangding and 0.69-1.25 for Yajiang. Moreover, all translocation factors of plants from the two sites were over 1.0. Therefore, M. sinensis can be classified as a Cd-accumulator or non-standard Cd-hyperaccumulator.

  13. Effectiveness of metal-metal and metal-organic compound combinations against Plutella xylostella: implications for plant elemental defense.

    PubMed

    Jhee, Edward M; Boyd, Robert S; Eubanks, Micky D

    2006-02-01

    Plants that contain elevated foliar metal concentrations can be categorized as accumulators or, if the accumulation is extreme, hyperaccumulators. The defense hypothesis suggests that these plants may be defended against folivore attack, and recent research has indicated that metal concentrations at or below the accumulator range may be defensively effective. This experiment explored the toxicity of four metals hyper-accumulated by plants (Cd, Ni, Pb, and Zn) and asked if combinations of metals, or metals and organic chemicals, might broaden the defensive effectiveness of metals. Metals were used alone and in certain metal + metal (Zn plus Ni, Pb, or Cd) and metal + organic defensive chemical (Ni plus tannic acid, atropine, or nicotine) combinations. Artificial diet amended with these treatments was fed to larvae of the crucifer specialist herbivore Plutella xylostella. Combinations of metals and metals + organic chemicals significantly decreased survival and pupation rates, compared to single treatments, for at least some concentrations in every experiment. Effects of combinations were additive rather than synergistic or antagonistic. Because Zn enhanced the toxicity of other metals and Ni enhanced the toxicity of organic defensive chemicals, our findings suggest that the defensive effects of metals are more widespread among plants than previously believed. They also support the hypothesis that herbivore defense may have led to the evolution of metal hyper-accumulation by increasing the preexisting defensive effects of metals at accumulator levels in plants.

  14. Evolutionary origins of abnormally large shoot sodium accumulation in nonsaline environments within the Caryophyllales.

    PubMed

    White, Philip J; Bowen, Helen C; Broadley, Martin R; El-Serehy, Hamed A; Neugebauer, Konrad; Taylor, Anna; Thompson, Jacqueline A; Wright, Gladys

    2017-04-01

    The prevalence of sodium (Na)-'hyperaccumulator' species, which exhibit abnormally large shoot sodium concentrations ([Na]shoot ) when grown in nonsaline environments, was investigated among angiosperms in general and within the Caryophyllales order in particular. Shoot Na concentrations were determined in 334 angiosperm species, representing 35 orders, grown hydroponically in a nonsaline solution. Many Caryophyllales species exhibited abnormally large [Na]shoot when grown hydroponically in a nonsaline solution. The bimodal distribution of the log-normal [Na]shoot of species within the Caryophyllales suggested at least two distinct [Na]shoot phenotypes within this order. Mapping the trait of Na-hyperaccumulation onto the phylogenetic relationships between Caryophyllales families, and between subfamilies within the Amaranthaceae, suggested that the trait evolved several times within this order: in an ancestor of the Aizoaceae, but not the Phytolaccaceae or Nyctaginaceae, in ancestors of several lineages formerly classified as Chenopodiaceae, but not in the Amaranthaceae sensu stricto, and in ancestors of species within the Cactaceae, Portulacaceae, Plumbaginaceae, Tamaricaceae and Polygonaceae. In conclusion, a disproportionate number of Caryophyllales species behave as Na-hyperaccumulators, and multiple evolutionary origins of this trait can be identified within this order.

  15. Lithium, Vanadium and Chromium Uptake Ability of Brassica juncea from Lithium Mine Tailings.

    PubMed

    Elektorowicz, M; Keropian, Z

    2015-01-01

    The potential for phytoremediation and phytostabilization of lithium in lieu with vanadium and chromium on a formulated acidic heterogeneous growth media engineered around lithium mine tailings, was investigated in four phases: (1) overall efficiency of the removal of the three metals, (2) bioaccumulation ratios of the three metals, (3) overall relative growth rate, and (4) translocation index of the three metals in the physiology of the hyperaccumulator plant. A pot study was conducted to assess the suitability of Brassica juncea (Indian mustard) in a phytoremediation process whereby it was lingered for eighty-six days under homogeneous growth conditions and irrigated bidaily with organic fertilizer amended with LiCl. A post harvest data analysis was achieved through ashing and the implementation of cold digestion procedure in a concentrated hydrochloric acidic matrix. In physiological efficiency parameters, the hyperaccumulator plant was twice as able to phytostabilize chromium and four times was able to phytostabilize vanadium in comparison to lithium. Moreover, it was extremely efficient in translocating and accumulating lithium inside its upper physiological sites, more so than chromium and vanadium, thereby demonstrating Indian mustard, as a hyperaccumulator plant, for phytoextraction and phytostabilization in an acidic heterogeneous rhizosphere, with an extremely low relative growth rate.

  16. Chelator-buffered nutrient solution is ineffective in extracting Ni from seeds of Alyssum.

    PubMed

    Centofanti, Tiziana; Tappero, Ryan V; Davis, Allen P; Chaney, Rufus L

    2011-01-01

    Hyperaccumulator species of the genera Alyssum can accumulate 100 times more Ni than normal crops and are therefore used for phytomining and phytoextraction of nickel contaminated soils. Basic studies on the physiology and metal uptake mechanisms of these plants are needed to increase efficiency and uptake capacity of Nickel (Ni) by hyperaccumulators. Recent attempts to disclose if those hyperaccumulator species require higher Ni level than normal plants failed because of the high Ni content in the seeds (7000-9000 microg g(-1)). In this study, we attempted to use chelator buffered nutrient solution to deplete Ni from the seed/seed coat and to obtain low Ni seedlings of Alyssum cultivars to be used in physiology studies. HEDTA-buffered nutrient solution did not deplete Ni from the seeds, perhaps because Ni was mainly localized within the seedling embryonic tissues with greatest Ni enrichment in the cotyledons and hypocotyls. We could not observe any positive correlation between seed fitness and germination capacity with seed Ni content. Investigation of nickel localization in Alyssum seeds using synchrotron X-ray microfluorescence (micro-SXRF) showed that nickel is localized in the embryonic tissues with greatest Ni enrichment observed in the cotyledons and hypocotyl.

  17. Effect of long-term stress of high Pb/Zn levels on genomic variation of Sedum alfredii Hance.

    PubMed

    Chao, Y E; Feng, Y; Yang, X E; Liu, D

    2008-11-01

    In this study, the heavy metal contents were detected in plants of Sedum alfredii and soils from Pb/Zn mined area and non-mined area, and a dendrogram was generated by using RAPD methods based on the hyperaccumulating ecotype (HE), the non-hyperaccumulating ecotype (NHE) and other species of Sedum. The results showed that the available Pb of the Pb/Zn mined soil was 77-fold higher, and available Zn and Cd were 10-fold and 16-fold higher in the mined soil than in the non-mined soil, respectively. The dendrogram showed that the HE S. alfredii was the nearest relative to NHE S. alfredii. However, genomic variation of two ecotypes was still notable, indicating that heavy metal stress had great impacts on the genetic diversity and plant evolution, and HE may be a mutant from the NHE. Ten RAPD bands were observed only in the HE as compared with other species of Sedum. The character of Zn/Cd hyperaccumulation in HE appeared to be related to SH-containing compounds and resist osmotic stress, and also many unknown genes.

  18. The yeast Aft2 transcription factor determines selenite toxicity by controlling the low affinity phosphate transport system

    PubMed Central

    Pérez-Sampietro, María; Serra-Cardona, Albert; Canadell, David; Casas, Celia; Ariño, Joaquín; Herrero, Enrique

    2016-01-01

    The yeast Saccharomyces cerevisiae is employed as a model to study the cellular mechanisms of toxicity and defense against selenite, the most frequent environmental selenium form. We show that yeast cells lacking Aft2, a transcription factor that together with Aft1 regulates iron homeostasis, are highly sensitive to selenite but, in contrast to aft1 mutants, this is not rescued by iron supplementation. The absence of Aft2 strongly potentiates the transcriptional responses to selenite, particularly for DNA damage- and oxidative stress-responsive genes, and results in intracellular hyperaccumulation of selenium. Overexpression of PHO4, the transcriptional activator of the PHO regulon under low phosphate conditions, partially reverses sensitivity and hyperaccumulation of selenite in a way that requires the presence of Spl2, a Pho4-controlled protein responsible for post-transcriptional downregulation of the low-affinity phosphate transporters Pho87 and Pho90. SPL2 expression is strongly downregulated in aft2 cells, especially upon selenite treatment. Selenite hypersensitivity of aft2 cells is fully rescued by deletion of PHO90, suggesting a major role for Pho90 in selenite uptake. We propose that the absence of Aft2 leads to enhanced Pho90 function, involving both Spl2-dependent and independent events and resulting in selenite hyperaccumulation and toxicity. PMID:27618952

  19. Kalimeris integrifolia Turcz. ex DC.: an accumulator of Cd.

    PubMed

    Wei, Shuhe; Zhou, Qixing; Srivastava, Mrittunjai; Xiao, Hong; Yang, Chuanjie; Zhang, Qianru

    2009-03-15

    Phytoremediation is a traditional technique that uses vegetation to remediate contaminants from water, soil and sediments. This is a solar-driven, aesthetically pleasing, and cost effective technology. In a former published article, Kalimeris integrifolia Turcz. ex DC. indicated some basic properties of hyperaccumulators for cadmium (Cd). In this study, concentration gradient experiment and sample-analyzing experiments were used to assess whether this plant is a Cd-hyperaccumulator. The results showed the Cd enrichment factor (concentration in plant/soil) and Cd translocation factor (concentration in shoot/root) of K. integrifolia was basically >1 in concentration gradient experiment. Shoot biomass was not reduced significantly (p<0.05) compared to the control. However, the Cd concentration in K. integrifolia shoots was not higher than 100 mg kg(-1), the threshold concentration for a Cd-hyperaccumulator. Thus, K. integrifolia should only be considered as a Cd-accumulator. In the sample-analyzing experiments conducted in a Pb-Zn mine area and a wastewater irrigation region, K. integrifolia also showed Cd-accumulator properties. Based on these results, K. integrifolia could be identified as a Cd-accumulator.

  20. Advancing our understanding of plant adaptation to metal polluted environments - new insights from Biscutella laevigata

    NASA Astrophysics Data System (ADS)

    Babst-Kostecka, Alicja; Waldmann, Patrik; Frérot, Hélène; Vollenweider, Pierre

    2016-04-01

    The legacy of industrial pollution alters ecosystems, particularly at post-mining sites where metal trace elements have created toxic conditions that trigger rapid plant adaptation. Apart from the purely scientific merits, in-depth knowledge of the mechanisms underlying plant adaptation to metal contamination is beneficial for the economic and societal sectors because of its application in bioengineering (e.g. phytoremediation or biofortification). An important process is the evolution and/or enhancement of metal tolerance, a trait that has predominantly been studied by applying acute metal stress on species that allocate large quantities of certain metals to their foliage (so-called hyperaccumulators). As the vast majority of vascular plants does not hyperaccumulate metals, more efforts are needed to investigate non-hyperaccumulating species and thereby broaden understanding of biological mechanisms underlying metal tolerance. The pseudometallophyte Biscutella laevigata has shown potential in this respect, but its characteristics are insufficiently understood. We determined the zinc tolerance level and various plant responses to environmentally relevant zinc concentrations in ten metallicolous and non-metallicolous B. laevigata populations. In a two-phase hydroponic experiment, we scored multiple morphological and physiological traits (e.g. biomass, visible stress symptoms, element content in foliage) and assessed phenotypic variability within plant families. The structure of these quantitative traits was compared to that of neutral molecular markers to test, whether natural selection caused population differentiation in zinc tolerance. While all genotypes were tolerant compared to a zinc sensitive reference species, we found congruent trends toward higher tolerance in metallicolous compared to non-metallicolous plants. We identified the most indicative parameters for these differences and find that enhanced zinc tolerance in metallicolous populations is driven by

  1. [Cd Runoff Load and Soil Profile Movement After Implementation of Some Typical Contaminated Agricultural Soil Remediation Strategies].

    PubMed

    Liu, Xiao-li; Zeng, Zhao-xia; Tie, Bai-qing; Chen, Qiu-wen; Wei, Xiang-dong

    2016-02-15

    Owing to the strong ability to immobilize and hyperaccumulate some toxic heavy metals in contaminated soils, the biochar, lime and such as hyperaccumulator ramie received increasing interests from crops and environment safety in recent years. Outdoor pot experiment was conducted to compare the impacts of lime and biochar addition in paddy rice treatment, hyperaccumulator ramie and ramie combined with EDTA of plant Phytoremediation methods on soil available Cd dynamics in rainfall runoff and the mobility along soil profile, under both natural acid precipitation and acid soil conditions. The results showed that, biochar addition at a 2% mass ratio application amount significantly increased soil pH, while ramie with EDTA application obviously decreased soil pH compared to ramie monoculture. Within the same rainfall events, water soluble Cd concentration in surface runoff of ramie treatments was significantly higher than those of waterlogged rice treatments, and Cd concentration in runoff was obviously increased after EDTA addition, whereas lime at a 0.3% mass ratio application amount as additive had no obvious impact on soil pH and Cd speciation change, which may be due to the low application amount. During the whole experimental period , water soluble Cd concentration of rainfall runoff in spring was higher than that in summer, showing the same seasonal characteristics in all treatments. Biochar addition could significantly decrease available Cd content in 0-20 cm soil layer and with certain preferable persistency effects, whereas EDTA addition treatment obviously increased available Cd of 0-20 cm soil layer compared to other treatments, and obvious Cd element activation phenomenon in 20-40 cm soil layer was observed after EDTA addition. In conclusion, lime and biochar as environmental and friendly alkaline Cd immobilization materials showed lower environment risk to surface and ground receiving water, but attention should be paid to phytoremediation enhanced with

  2. Utilization of a Model for Uptake of Cadmium by Plants as a Phytoremediation Assessment Tool

    NASA Astrophysics Data System (ADS)

    Takahashi, M.; Furbish, D. J.; Clarke, J.

    2008-12-01

    Some traditional methods of environmental remediation, such as removal and disposal of contaminated soil, are loosing economic favor and public acceptance, while others, such as in situ phytoremediation, are being carefully examined because of their attractiveness as environmentally friendly, low-cost solutions to site clean-up. The success of phytoremediation strategies, however, hinges on the ability of selected plants, or plant communities, to effectively uptake, accumulate and tolerate targeted contaminants. Heavy metals, specifically cadmium (Cd), are not essential nutrients to plants. However, chemically similar zinc (Zn) is a micronutrient and is actively taken up by hyperaccumulators. For this reason, the mechanisms involved in uptake of Cd parallel those of Zn. Ideally, Cd would be allocated to the stem, leaf, and/or flower, where it becomes harvestable. Our modeling work simulates the uptake and the storage of Cd in a growing hyperaccumulator. After uptake, Cd is partitioned between adsorption to plant tissue and upward movement to leaves driven by transpiration. Uptake, adsorption and transport are also regulated by phytotoxicity. Simulations suggest that a young plant with small biomass can quickly reach phytotoxicity, which shuts down the normal operation of the plant. Conversely, mature plants on a mildly contaminated site, if harvested before the plants die due to phytotoxicity or natural cause, not only survive but may occasionally thrive. The immediate aim is to estimate the effectiveness and limitations of Cd uptake by hyperaccumulators. The eventual goal of this study is to expand the model in spatial and temporal scales, from individual plants to the community scale, and from one harvest interval to several generations. Understanding the interface between physical and biological processes, specifically the uptake and release of contaminants, provides scientists and engineers tools to assess whether phytoremediation is a reasonable strategy for a

  3. Screening of plant species for phytoremediation of uranium, thorium, barium, nickel, strontium and lead contaminated soils from a uranium mill tailings repository in South China.

    PubMed

    Li, Guang-yue; Hu, Nan; Ding, De-xin; Zheng, Ji-fang; Liu, Yu-long; Wang, Yong-dong; Nie, Xiao-qin

    2011-06-01

    The concentrations of uranium, thorium, barium, nickel, strontium and lead in the samples of the tailings and plant species collected from a uranium mill tailings repository in South China were analyzed. Then, the removal capability of a plant for a target element was assessed. It was found that Phragmites australis had the greatest removal capabilities for uranium (820 μg), thorium (103 μg) and lead (1,870 μg). Miscanthus floridulus had the greatest removal capabilities for barium (3,730 μg) and nickel (667 μg), and Parthenocissus quinquefolia had the greatest removal capability for strontium (3,920 μg). In this study, a novel coefficient, termed as phytoremediation factor (PF), was proposed, for the first time, to assess the potential of a plant to be used in phytoremediation of a target element contaminated soil. Phragmites australis has the highest PFs for uranium (16.6), thorium (8.68), barium (10.0) and lead (10.5). Miscanthus floridulus has the highest PF for Ni (25.0). Broussonetia papyrifera and Parthenocissus quinquefolia have the relatively high PFs for strontium (28.1 and 25.4, respectively). On the basis of the definition for a hyperaccumulator, only Cyperus iria and Parthenocissus quinquefolia satisfied the criteria for hyperaccumulator of uranium (36.4 μg/g) and strontium (190 μg/g), and could be the candidates for phytoremediation of uranium and strontium contaminated soils. The results show that the PF has advantage over the hyperaccumulator in reflecting the removal capabilities of a plant for a target element, and is more adequate for assessing the potential of a plant to be used in phytoremediation than conventional method.

  4. Imaging translocation and transformation of bioavailable selenium by Stanleya pinnata with X-ray microscopy.

    PubMed

    Amos, Wren; Webb, Samuel; Liu, Yijin; Andrews, Joy C; LeDuc, Danika L

    2012-09-01

    Selenium hyperaccumulator Stanleya pinnata, Colorado ecotype, was supplied with water-soluble and biologically available selenate or selenite. Selenium distribution and tissue speciation were established using X-ray microscopy (micro-X-ray fluorescence and transmission X-ray microscopy) in two dimensions and three dimensions. The results indicate that S. pinnata tolerates, accumulates, and volatilizes significant concentrations of selenium when the inorganic form supplied is selenite and may possess novel metabolic capacity to differentiate, metabolize, and detoxify selenite concentrations surpassing field concentrations. The results also indicate that S. pinnata is a feasible candidate to detoxify selenium-polluted soil sites, especially locations with topsoil polluted with soluble and biologically available selenite.

  5. Improved resolution and sensitivity on the ANSTO microprobe and it’s application to μ-PIXE

    NASA Astrophysics Data System (ADS)

    Siegele, R.; Kachenko, A. G.; Ionescu, M.; Cohen, D. D.

    2009-06-01

    We report on the improved spatial resolution of the ANSTO heavy ion microprobe, achieved through the use of a higher brightness ion source for hydrogen. The improved resolution will be demonstrated for applications of μ-PIXE. With the higher brightness source, a 3 μm resolution was achieved for μ-PIXE elemental analysis. This is illustrated in high resolution images of nickel (Ni)-hyperaccumulating Hybanthus floribundus subsp. floribundus leaf tissues, where individual cells were clearly visible in the acquired elemental images. The higher resolution images illustrated that Ni was localised in epidermal cell walls.

  6. Agromining: farming for metals in the future?

    PubMed

    van der Ent, Antony; Baker, Alan J M; Reeves, Roger D; Chaney, Rufus L; Anderson, Christopher W N; Meech, John A; Erskine, Peter D; Simonnot, Marie-Odile; Vaughan, James; Morel, Jean Louis; Echevarria, Guillaume; Fogliani, Bruno; Rongliang, Qiu; Mulligan, David R

    2015-04-21

    Phytomining technology employs hyperaccumulator plants to take up metal in harvestable plant biomass. Harvesting, drying and incineration of the biomass generates a high-grade bio-ore. We propose that "agromining" (a variant of phytomining) could provide local communities with an alternative type of agriculture on degraded lands; farming not for food crops, but for metals such as nickel (Ni). However, two decades after its inception and numerous successful experiments, commercial phytomining has not yet become a reality. To build the case for the minerals industry, a large-scale demonstration is needed to identify operational risks and provide "real-life" evidence for profitability.

  7. Assessment of Ni accumulation capability by fungi for a possible approach to remove metals from soils and waters.

    PubMed

    Cecchi, Grazia; Roccotiello, Enrica; Di Piazza, Simone; Riggi, Alex; Mariotti, Mauro Giorgio; Zotti, Mirca

    2017-03-04

    Abandoned industrial sites and mines may constitute possible hazards for surrounding environment due to the presence of toxic compounds that may contaminate soils and waters. The possibility to remove metal contaminants, specifically nickel (Ni), by means of fungi was presented exploiting a set of fungal strains isolated from a Ligurian dismissed mine. The achieved results demonstrate the high Ni(II) tolerance, up to 500 mg Ni l(-1), and removal capability of a Trichoderma harzianum strain. This latter hyperaccumulates up to 11,000 mg Ni kg(-1), suggesting its possible use in a bioremediation protocol able to provide a sustainable reclamation of broad contaminated areas.

  8. Composition, speciation and distribution of iron minerals in Imperata cylindrica.

    PubMed

    Amils, Ricardo; de la Fuente, Vicenta; Rodríguez, Nuria; Zuluaga, Javier; Menéndez, Nieves; Tornero, Jesús

    2007-05-01

    A comparative study of the roots, rhizomes and leaves of an iron hyperaccumulator plant, Imperata cylindrica, isolated from the banks of an extreme acidic environment, using complementary techniques: Mösbauer spectroscopy (MS), X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled to energy-dispersive X-ray microanalysis (EDAX) and transmission electron microscopy (TEM), has shown that two main biominerals, jarosite and ferrihydrate-ferritin, accumulate in the different tissues. Jarosite accumulates mainly in roots and rhizomes, while ferritin has been detected in all the structures. A model of iron management in I. cylindrica is presented.

  9. Mutations and environmental factors affecting regulation of riboflavin synthesis and iron assimilation also cause oxidative stress in the yeast Pichia guilliermondii.

    PubMed

    Boretsky, Yuriy R; Protchenko, Olga V; Prokopiv, Tetiana M; Mukalov, Igor O; Fedorovych, Daria V; Sibirny, Andriy A

    2007-10-01

    Iron deficiency causes oversynthesis of riboflavin in several yeast species, known as flavinogenic yeasts. However, the mechanisms of such regulation are not known. We found that mutations causing riboflavin overproduction and iron hyperaccumulation (rib80, rib81 and hit1), as well as cobalt excess or iron deficiency all provoke oxidative stress in the Pichia guilliermondii yeast. Iron content in the cells, production both of riboflavin and malondialdehyde by P. guilliermondii wild type and hit1 mutant strains depend on a type of carbon source used in cultivation media. The data suggest that the regulation of riboflavin biosynthesis and iron assimilation in P. guilliermondii are linked with cellular oxidative state.

  10. [Salivary glands and oral mucous membrane status in patients with chronic hepatitis].

    PubMed

    Afanas'ev, V V; Muromtsev, A V; Derkach, N V

    2008-01-01

    The status of salivary glands and oral mucous membrane was investigated in 50 patients with chronic active hepatitis against the background of chronic alcoholism. The check up disclosed sialadenosis in 38% of patients and in 54% of patients - such diseases of oral mucous membrane as stomatitis, candidosis and geographic tonque. Besides there were disclosed such disturbances as big and small salivary glands secretion reduction, mixed saliva viscosity increase, increase of protein, P, K, Na and catalase content in it, glycogen hyperaccumulation in gingival tissues. The received data indicated the necessity of dispensary supervision of such patients and their treatment in stomatologist.

  11. The green clean: The emerging field of phytoremediation takes root

    SciTech Connect

    Brown, K.S.

    1995-10-01

    A few plants can biologically accumulate toxic metals from surrounding soils, a situation that could revolutionize environmental cleanup. By breeding a planting metal-munchers like alpine pennycress, scientist plan to clease waste zones of toxic levels of zinc, nickel and lead. From soil loaded with metal to radionuclide-laden water, researcher hope phytoremediation will provide a cheap way to clean man-made messes at mining, nuclear, and industrial sites. This article describes developments in the area of phytoremediation, including sections on plants called hyperaccumulators, how phytoremediators function, problems transferring phytoremediators from hydroculture to soils and problems which might prevent use of phytoremediators.

  12. Effect of salinity on zinc uptake by Brassica juncea.

    PubMed

    Novo, Luís A B; Covelo, Emma F; González, Luís

    2014-01-01

    Salinity is a major worldwide problem that affects agricultural soils and limits the reclamation of contaminated sites. Despite the large number of research papers published about salt tolerance in Brassica juncea L., there are very few accounts concerning the influence of salinity on the uptake of trace metals. In this study, B. juncea plants divided through soil sets comprising 0, 900 and 1800 mg Zn kg(-1), were treated with solutions containing 0, 60 and 120 mmol L(-1) of NaCl, with the purpose of observing the effect of salt on Zn uptake, and some physiological responses throughout the 90 days experiment. Increasing concentrations of NaCl and Zn produced a decline in the ecophysiological and biochemical properties of the plants, with observable synergistic effects on parameters like shoot dry weight, leaf area, or photochemical efficiency. Nevertheless, plants treated with 60 mmol L(-1) of NaCl accumulated striking harvestable amounts of Zn per plant that largely exceed those reported for Thlaspi caerulescens. It was concluded that salinity could play an important role on the uptake of Zn by B. juncea. The potential mechanisms behind these results are discussed, as well as the implications for phytoremediation of Zn on saline and non-saline soils.

  13. Cloning and characterization of the nicotianamine synthase gene in Eruca vesicaria subsp sativa.

    PubMed

    Huang, B L; Cheng, C; Zhang, G Y; Su, J J; Zhi, Y; Xu, S S; Cai, D T; Zhang, X K; Huang, B Q

    2015-12-22

    Nicotianamine (NA) is a ubiquitous metabolite in plants that bind heavy metals, is crucial for metal homeostasis, and is also an important metal chelator that facilitates long-distance metal transport and sequestration. NA synthesis is catalyzed by the enzyme nicotianamine synthase (NAS). Eruca vesicaria subsp sativa is highly tolerant to Ni, Pb, and Zn. In this study, a gene encoding EvNAS was cloned and characterized in E. vesicaria subsp sativa. The full-length EvNAS cDNA sequence contained a 111-bp 5'-untranslated region (UTR), a 155-bp 3'-UTR, and a 966-bp open reading frame encoding 322-amino acid residues. The EvNAS genomic sequence contained no introns, which is similar to previously reported NAS genes. The deduced translation of EvNAS contained a well-conserved NAS domain (1-279 amino acids) and an LIKI-CGEAEG box identical to some Brassica NAS and to the LIRL-box in most plant NAS, which is essential for DNA binding. Phylogenetic analysis indicated that EvNAS was most closely related to Brassica rapa NAS3 within the Cruciferae, followed by Thlaspi NAS1, Camelina NAS3, and Arabidopsis NAS3. A reverse transcription-polymerase chain reaction indicated that EvNAS expression was greatest in the leaves, followed by the flower buds and hypocotyls. EvNAS was moderately expressed in the roots.

  14. Seed Detection and Discrimination by Ground Beetles (Coleoptera: Carabidae) Are Associated with Olfactory Cues.

    PubMed

    Kulkarni, Sharavari S; Dosdall, Lloyd M; Spence, John R; Willenborg, Christian J

    2017-01-01

    Olfactory ability is an element of fitness in many animals, guiding choices among alternatives such as mating partners or food. Ground beetles (Coleoptera; Carabidae), exhibit preferences for prey, and some species are well-known weed seed predators. We used olfactometer-based bioassays to determine if olfactory stimuli are associated with detection of Brassica napus L., Sinapis arvensis L., and Thlaspi arvense L. seeds by ground beetles characteristic of agroecosystems, and whether behavioural responses to seed odors depended on seed physiological state (imbibed or unimbibed). Imbibed B.napus seeds were preferred over other weed species by two of the three carabid species tested. Only A. littoralis responded significantly to unimbibed seeds of B. napus. Sensitivity to olfactory cues appeared to be highly specific as all carabid species discriminated between the olfactory cues of imbibed brassicaceous weed seeds, but did not discriminate between weed seeds that were unimbibed. Overall, our data suggest that depending on seed physiological state, odours can play an important role in the ability of carabids to find and recognize seeds of particular weed species.

  15. Crystal structure of the Epithiospecifier Protein, ESP from Arabidopsis thaliana provides insights into its product specificity.

    PubMed

    Zhang, Weiwei; Wang, Wenhe; Liu, Zihe; Xie, Yongchao; Wang, Hao; Mu, Yajuan; Huang, Yao; Feng, Yue

    2016-09-16

    Specifier proteins are important components of the glucosinolate-myrosinase system, which mediate plant defense against herbivory and pathogen attacks. Upon tissue disruption, glucosinolates are hydrolyzed to instable aglucones by myrosinases, and then aglucones will rearrange to form defensive isothiocyanates. Specifier proteins can redirect this reaction to form other products, such as simple nitriles, epithionitriles and organic thiocyanates instead of isothiocyanates based on the side chain structure of glucosinolate and the type of the specifier proteins. Nevertheless, the molecular mechanism underlying the different product spectrums of various specifier proteins was not fully understood. Here in this study, we solved the crystal structure of the Epithiospecifier Protein, ESP from Arabidopsis thaliana (AtESP) at 2.3 Å resolution. Structural comparisons with the previously solved structure of thiocyanate forming protein, TFP from Thlaspi arvense (TaTFP) reveal that AtESP shows a dimerization pattern different from TaTFP. Moreover, AtESP harbors a slightly larger active site pocket than TaTFP and several residues around the active site are different between the two proteins, which might account for the different product spectrums of the two proteins. Together, our structural study provides important insights into the molecular mechanisms of specifier proteins and shed light on the basis of their different product spectrums.

  16. Toxic metal accumulation, responses to exposure and mechanisms of tolerance in plants.

    PubMed

    Clemens, S

    2006-11-01

    Over the past 200 years emissions of toxic heavy metals have risen tremendously and significantly exceed those from natural sources for practically all metals. Uptake and accumulation by crop plants represents the main entry pathway for potentially health-threatening toxic metals into human and animal food. Of major concern are the metalloids arsenic (As) and selenium (Se), and the metals cadmium (Cd), mercury (Hg), and lead (Pb). This review discusses the molecular mechanisms of toxic metal accumulation in plants and algae, the responses to metal exposure, as well as our understanding of metal tolerance and its evolution. The main emphasis will be on cadmium, which is by far the most widely studied of the non-essential toxic metals/metalloids. Entry via Zn2+, Fe2+, and Ca2+ transporters is the molecular basis of Cd2+ uptake into plant cells. Much less is known about the partitioning of non-essential metals and about the genes underlying the enormous diversity among plants with respect to Cd accumulation in different tissues. Numerous studies have described symptoms and responses of plants upon toxic metal exposure. Mysterious are primary targets of toxicity, the degree of specificity of responses, the sensing and the signaling events that lead to transcriptional activation. All plants apparently possess a basal tolerance of toxic non-essential metals. For Cd and As, this is largely dependent on the phytochelatin pathway. Not understood is the molecular biology of Cd hypertolerance in certain plant species such as the metallophytes Arabidopsis halleri or Thlaspi caerulescens.

  17. The construction of an engineered bacterium to remove cadmium from wastewater.

    PubMed

    Chang, S; Shu, H

    2014-01-01

    The removal of cadmium (Cd) from wastewater before it is released from factories is important for protecting human health. Although some researchers have developed engineered bacteria, the resistance of these engineered bacteria to Cd have not been improved. In this study, two key genes involved in glutathione synthesis (gshA and gshB), a serine acetyltransferase gene (cysE), a Thlaspi caerulescens phytochelatin synthase gene (TcPCS1), and a heavy metal ATPase gene (TcHMA3) were transformed into Escherichia coli BL21. The resistance of the engineered bacterium to Cd was significantly greater than that of the initial bacterium and the Cd accumulation in the engineered bacterium was much higher than in the initial bacterium. In addition, the Cd resistance of the bacteria harboring gshB, gshA, cysE, and TcPCS1 was higher than that of the bacteria harboring gshA, cysE, and TcPCS1. This finding demonstrated that gshB played an important role in glutathione synthesis and that the reaction catalyzed by glutathione synthase was the limiting step for producing phytochelatins. Furthermore, TcPCS1 had a greater specificity and a higher capacity for removing Cd than SpPCS1, and TcHMA3 not only played a role in T. caerulescens but also functioned in E. coli.

  18. Seed Detection and Discrimination by Ground Beetles (Coleoptera: Carabidae) Are Associated with Olfactory Cues

    PubMed Central

    2017-01-01

    Olfactory ability is an element of fitness in many animals, guiding choices among alternatives such as mating partners or food. Ground beetles (Coleoptera; Carabidae), exhibit preferences for prey, and some species are well-known weed seed predators. We used olfactometer-based bioassays to determine if olfactory stimuli are associated with detection of Brassica napus L., Sinapis arvensis L., and Thlaspi arvense L. seeds by ground beetles characteristic of agroecosystems, and whether behavioural responses to seed odors depended on seed physiological state (imbibed or unimbibed). Imbibed B.napus seeds were preferred over other weed species by two of the three carabid species tested. Only A. littoralis responded significantly to unimbibed seeds of B. napus. Sensitivity to olfactory cues appeared to be highly specific as all carabid species discriminated between the olfactory cues of imbibed brassicaceous weed seeds, but did not discriminate between weed seeds that were unimbibed. Overall, our data suggest that depending on seed physiological state, odours can play an important role in the ability of carabids to find and recognize seeds of particular weed species. PMID:28107464

  19. Isolation of gibberellin precursors from heavily pigmented tissues.

    PubMed

    Metzger, J D; Hazebroek, J P

    1989-12-01

    The kauranoid precursors of gibberellins are difficult to isolate from heavily pigmented plant tissues. In this paper, we describe relatively simple and efficient procedures for the purification of these compounds from tissues containing chlorophyll and other high molecular weight pigments. Extracts of shoots from Thlaspi arvense L. were subjected first to size exclusion chromatography using ethyl acetate as the eluting solvent. This procedure resulted in the separation of kauranoids as a class of compounds from chlorophyll. Typically, a 90% reduction in mass of the kauranoid enriched-fraction was observed. This fraction was subjected to reverse phase high performance liquid chromatography and individual fractions analyzed by combined gas chromatography-mass spectrometry. Five kauranoids were identified in shoot extracts of T. arvense: ent-kaur-16-ene, ent-kaur-16-en-19-ol, ent-kaur-16-en-19-oic acid, trachylobanoic acid, and 7beta, 13-dihydroxykaurenolide. The metabolic relationships of these compounds to the gibberellins previously identified in this species (JD Metzger, MC Mardaus [1986] Plant Physiol 80: 396-402) are discussed. In addition, the utility of size exclusion chromatography in preparative situations is demonstrated by the purification of ent-kaurenoic acid in milligram quantities from the florets of Helianthus annuus L.

  20. Zinc triggers a complex transcriptional and post-transcriptional regulation of the metal homeostasis gene FRD3 in Arabidopsis relatives

    PubMed Central

    Charlier, Jean-Benoit; Polese, Catherine; Nouet, Cécile; Carnol, Monique; Bosman, Bernard; Krämer, Ute; Motte, Patrick; Hanikenne, Marc

    2015-01-01

    In Arabidopsis thaliana, FRD3 (FERRIC CHELATE REDUCTASE DEFECTIVE 3) plays a central role in metal homeostasis. FRD3 is among a set of metal homeostasis genes that are constitutively highly expressed in roots and shoots of Arabidopsis halleri, a zinc hyperaccumulating and hypertolerant species. Here, we examined the regulation of FRD3 by zinc in both species to shed light on the evolutionary processes underlying the evolution of hyperaccumulation in A. halleri. We combined gene expression studies with the use of β-glucuronidase and green fluorescent protein reporter constructs to compare the expression profile and transcriptional and post-transcriptional regulation of FRD3 in both species. The AtFRD3 and AhFRD3 genes displayed a conserved expression profile. In A. thaliana, alternative transcription initiation sites from two promoters determined transcript variants that were differentially regulated by zinc supply in roots and shoots to favour the most highly translated variant under zinc-excess conditions. In A. halleri, a single transcript variant with higher transcript stability and enhanced translation has been maintained. The FRD3 gene thus undergoes complex transcriptional and post-transcriptional regulation in Arabidopsis relatives. Our study reveals that a diverse set of mechanisms underlie increased gene dosage in the A. halleri lineage and illustrates how an environmental challenge can alter gene regulation. PMID:25900619

  1. Control of Zn uptake in Arabidopsis halleri: a balance between Zn and Fe

    PubMed Central

    Shanmugam, Varanavasiappan; Lo, Jing-Chi; Yeh, Kuo-Chen

    2013-01-01

    Zinc (Zn) is an essential plant micronutrient but is toxic in excess. To cope with excess Zn, plant species possess a strict metal homeostasis mechanism. The Zn hyperaccumulator Arabidopsis halleri has developed various adaptive mechanisms involving uptake, chelation, translocation and sequestration of Zn. In this mini review, we broadly discuss the different Zn tolerance mechanisms and then focus on controlled Zn uptake in A. halleri. Members of the ZRT/IRT-like protein (ZIP) family of metal transporters are mainly regulated by Zn and are involved in Zn uptake. A few members of the ZIP family, such as IRT1 and IRT2, are regulated by iron (Fe) and can transport multi-metals, including Zn, Fe, Mn, Cd, and Co. This mini-review also discusses the differential expression of multiple metal ZIP transporters in A. halleri and A. thaliana, a non-hyperaccumulator, with Zn exposure as well as Fe deficiency and their role in controlled Zn uptake and tolerance. PMID:23966999

  2. Boron stress response and accumulation potential of the extremely tolerant species Puccinellia frigida.

    PubMed

    Rámila, Consuelo D P; Contreras, Samuel A; Di Domenico, Camila; Molina-Montenegro, Marco A; Vega, Andrea; Handford, Michael; Bonilla, Carlos A; Pizarro, Gonzalo E

    2016-11-05

    Phytoremediation is a promising technology to tackle boron toxicity, which restricts agricultural activities in many arid and semi-arid areas. Puccinellia frigida is a perennial grass that was reported to hyperaccumulate boron in extremely boron-contaminated sites. To further investigate its potential for phytoremediation, we determined its response to boron stress under controlled conditions (hydroponic culture). Also, as a first step towards understanding the mechanisms underlying its extreme tolerance, we evaluated the presence and expression of genes related with boron tolerance. We found that P. frigida grew normally even at highly toxic boron concentrations in the medium (500mg/L), and within its tissues (>5000mg/kg DW). We postulate that the strategies conferring this extreme tolerance involve both restricting boron accumulation and an internal tolerance mechanism; this is consistent with the identification of putative genes involved in both mechanisms, including the expression of a possible boron efflux transporter. We also found that P. frigida hyperaccumulated boron over a wide range of boron concentrations. We propose that P. frigida could be used for boron phytoremediation strategies in places with different soil characteristics and boron concentrations. Further studies should pave the way for the development of clean and low-cost solutions to boron toxicity problems.

  3. Control of lead polluted leachate in a box-scale phytoremediation test using common buckwheat (Fagopyrum esculentum Moench) grown on lead contaminated soil.

    PubMed

    Honda, M; Tamura, H; Kimura, T; Kinoshita, T; Matsufuru, H; Sato, T

    2007-04-01

    The remediation of heavy metal contaminated soil using plants is a technology worth developing. However, the overall effect of phytoremediation in high-density Pb polluted sites remains unknown. Especially, little information is available about the effects of using plants to control lead polluted leachate. Thus, we investigated the control of leachate in a box-scale phytoremediation test using common buckwheat, a Pb hyperaccumulator, grown on Pb contaminated soil. In the presence of buckwheat, the change in volumetric water content was smaller than that of the control with rainfall. The total amount of Pb in the leachate strongly correlated with the amount of leachate and the decrease in the density of Pb in the leachate. During the cultivation period, the total amount of Pb leached in the control was 1.28mg per container, while in the presence of buckwheat the total amount of Pb was approximately 22.7% of the control. Moreover, with buckwheat cultivation, Pb polluted leachate resulting from rainwater was prevented. The results suggested that buckwheat was a Pb hyperaccumulator and also had a high ability for phytostabilization. Control of Pb polluted leachate using buckwheat was shown to be a phytoremediation technology applicable to heavily Pb contaminated sites.

  4. The psychedelic genes of maize redundantly promote carbohydrate export from leaves.

    PubMed

    Slewinski, Thomas L; Braun, David M

    2010-05-01

    Whole-plant carbohydrate partitioning involves the assimilation of carbon in leaves and its translocation to nonphotosynthetic tissues. This process is fundamental to plant growth and development, but its regulation is poorly understood. To identify genes controlling carbohydrate partitioning, we isolated mutants that are defective in exporting fixed carbon from leaves. Here we describe psychedelic (psc), a new mutant of maize (Zea mays) that is perturbed in carbohydrate partitioning. psc mutants exhibit stable, discrete chlorotic and green regions within their leaves. psc chlorotic tissues hyperaccumulate starch and soluble sugars, while psc green tissues appear comparable to wild-type leaves. The psc chlorotic and green tissue boundaries are usually delineated by larger veins, suggesting that translocation of a mobile compound through the veins may influence the tissue phenotype. psc mutants display altered biomass partitioning, which is consistent with reduced carbohydrate export from leaves to developing tissues. We determined that the psc mutation is unlinked to previously characterized maize leaf carbohydrate hyperaccumulation mutants. Additionally, we found that the psc mutant phenotype is inherited as a recessive, duplicate-factor trait in some inbred lines. Genetic analyses with other maize mutants with variegated leaves and impaired carbohydrate partitioning suggest that Psc defines an independent pathway. Therefore, investigations into the psc mutation have uncovered two previously unknown genes that redundantly function to regulate carbohydrate partitioning in maize.

  5. Enhancement of lead uptake by alfalfa (Medicago sativa) using EDTA and a plant growth promoter.

    PubMed

    López, Martha L; Peralta-Videa, Jose R; Benitez, Tenoch; Gardea-Torresdey, Jorge L

    2005-10-01

    Phytoremediation is a novel cleanup technology for the removal of contaminants from polluted waters and soils. In phytoremediation, the plant uptake capability and the availability of the pollutant in the media are important. Here we show the results of a study on the combined effects of ethylenediaminetetraacetic acid (EDTA) and the phytohormone indole-3-acetic acid (IAA) on Pb uptake by Medicago sativa (alfalfa). Plants were grown in hydroponics media containing a nutrient solution amended with Pb at 0.2mM and different combinations of EDTA, and IAA. After 10d of treatment, the Pb content in plant tissues was quantified using an Inductively Coupled Plasma Optical Emission Spectrometer (ICP/OES). The results showed that the combination of 100 microM IAA/0.2 mM EDTA increased the Pb accumulation in leaves by about 2800% and by about 600%, as compared to Pb content in leaves of plants exposed to Pb alone and those cultivated with Pb/EDTA, respectively. These results indicate that non-metal hyperaccumulator plants could increase their hyperaccumulating potential without genetic manipulation.

  6. Phytoremediation of wastewater containing lead (Pb) in pilot reed bed using Scirpus grossus.

    PubMed

    Tangahu, Bieby Voijant; Abdullah, Siti Rozaimah Sheikh; Basri, Hassan; Idris, Mushrifah; Anuar, Nurina; Mukhlisin, Muhammad

    2013-01-01

    Phytoremediation is a technology to clean the environment from heavy metals contamination. The objectives of this study are to threat Pb contaminated wastewater by using phytoremediation technology and to determine if the plant can be mention as hyperaccumulator. Fifty plants of Scirpus grossus were grown in sand medium and 600 L spiked water in various Pb concentration (10, 30 and 50 mg/L) was exposed. The experiment was conducted with single exposure method, sampling time on day-1, day-14, day-28, day-42, day-70, and day-98. The analysis of Pb concentration in water, sand medium and inside the plant tissue was conducted by ICP-OES. Water samples were filtered and Pb concentration were directly analyzed, Pb in sand samples were extracted by EDTA method before analyzed, and Pb in plant tissues were extracted by wet digestion method and analyzed. The results showed that on day-28, Pb concentration in water decreased 100%, 99.9%, 99.7%, and the highest Pb uptake by plant were 1343, 4909, 3236 mg/kg for the treatment of 10, 30, and 50 mg/L respectively. The highest BC and TF were 485,261 on day-42 and 2.5295 on day-70 of treatment 30 mg/L, it can be mentioned that Scirpus grossus is a hyperaccumulator.

  7. Roles of plant metal tolerance proteins (MTP) in metal storage and potential use in biofortification strategies.

    PubMed

    Ricachenevsky, Felipe K; Menguer, Paloma K; Sperotto, Raul A; Williams, Lorraine E; Fett, Janette P

    2013-01-01

    Zinc (Zn) is an essential micronutrient for plants, playing catalytic or structural roles in enzymes, transcription factors, ribosomes, and membranes. In humans, Zn deficiency is the second most common mineral nutritional disorder, affecting around 30% of the world's population. People living in poverty usually have diets based on milled cereals, which contain low Zn concentrations. Biofortification of crops is an attractive cost-effective solution for low mineral dietary intake. In order to increase the amounts of bioavailable Zn in crop edible portions, it is necessary to understand how plants take up, distribute, and store Zn within their tissues, as well as to characterize potential candidate genes for biotechnological manipulation. The metal tolerance proteins (MTP) were described as metal efflux transporters from the cytoplasm, transporting mainly Zn(2+) but also Mn(2+), Fe(2+), Cd(2+), Co(2+), and Ni(2+). Substrate specificity appears to be conserved in phylogenetically related proteins. MTPs characterized so far in plants have a role in general Zn homeostasis and tolerance to Zn excess; in tolerance to excess Mn and also in the response to iron (Fe) deficiency. More recently, the first MTPs in crop species have been functionally characterized. In Zn hyperaccumulator plants, the MTP1 protein is related to hypertolerance to elevated Zn concentrations. Here, we review the current knowledge on this protein family, as well as biochemical functions and physiological roles of MTP transporters in Zn hyperaccumulators and non-accumulators. The potential applications of MTP transporters in biofortification efforts are discussed.

  8. Got to hide your Zn away: Molecular control of Zn accumulation and biotechnological applications.

    PubMed

    Ricachenevsky, Felipe Klein; Menguer, Paloma Koprovski; Sperotto, Raul Antonio; Fett, Janette Palma

    2015-07-01

    Zinc (Zn) is an essential micronutrient for all organisms, with key catalytic and structural functions. Zn deficiency in plants, common in alkaline soils, results in growth arrest and sterility. On the other hand, Zn can become toxic at elevated concentrations. Several studies revealed molecules involved with metal acquisition in roots, distribution within the plant and translocation to seeds. Transmembrane Zn transport proteins and Zn chelators are involved in avoiding its toxic effects. Plant species with the capacity to hyperaccumulate and hypertolerate Zn have been characterized. Plants that accumulate and tolerate high amounts of Zn and produce abundant biomass may be useful for phytoremediation, allowing cleaning of metal-contaminated soils. The study of Zn hyperaccumulators may provide indications of genes and processes useful for biofortification, for developing crops with high amounts of nutrients in edible tissues. Future research needs to focus on functional characterization of Zn transporters in planta, elucidation of Zn uptake and sensing mechanisms, and on understanding the cross-talk between Zn homeostasis and other physiological processes. For this, new research should use multidisciplinary approaches, combining traditional and emerging techniques, such as genome-encoded metal sensors and multi-element imaging, quantification and speciation using synchrotron-based methods.

  9. Selenium accumulation in flowers and its effects on pollination.

    PubMed

    Quinn, Colin F; Prins, Christine N; Freeman, John L; Gross, Amanda M; Hantzis, Laura J; Reynolds, Ray J B; Yang, Soo in; Covey, Paul A; Bañuelos, Gary S; Pickering, Ingrid J; Fakra, Sirine C; Marcus, Matthew A; Arathi, H S; Pilon-Smits, Elizabeth A H

    2011-11-01

    • Selenium (Se) hyperaccumulation has a profound effect on plant-arthropod interactions. Here, we investigated floral Se distribution and speciation in flowers and the effects of floral Se on pollen quality and plant-pollinator interactions. • Floral Se distribution and speciation were compared in Stanleya pinnata, an Se hyperaccumulator, and Brassica juncea, a comparable nonhyperaccumulator. Pollen germination was measured from plants grown with varying concentrations of Se and floral visitation was compared between plants with high and low Se. • Stanleya pinnata preferentially allocated Se to flowers, as nontoxic methyl-selenocysteine (MeSeCys). Brassica juncea had higher Se concentrations in leaves than flowers, and a lower fraction of MeSeCys. For B. juncea, high floral Se concentration impaired pollen germination; in S. pinnata Se had no effect on pollen germination. Floral visitors collected from Se-rich S. pinnata contained up to 270 μg g(-1), concentrations toxic to many herbivores. Indeed, floral visitors showed no visitation preference between high- and low-Se plants. Honey from seleniferous areas contained 0.4-1 μg Se g(-1), concentrations that could provide human health benefits. • This study is the first to shed light on the possible evolutionary cost, through decreased pollen germination in B. juncea, of Se accumulation and has implications for the management of seleniferous areas.

  10. Chemically Induced Conditional Rescue of the Reduced Epidermal Fluorescence8 Mutant of Arabidopsis Reveals Rapid Restoration of Growth and Selective Turnover of Secondary Metabolite Pools1[C][OPEN

    PubMed Central

    Kim, Jeong Im; Ciesielski, Peter N.; Donohoe, Bryon S.; Chapple, Clint; Li, Xu

    2014-01-01

    The phenylpropanoid pathway is responsible for the biosynthesis of diverse and important secondary metabolites including lignin and flavonoids. The reduced epidermal fluorescence8 (ref8) mutant of Arabidopsis (Arabidopsis thaliana), which is defective in a lignin biosynthetic enzyme p-coumaroyl shikimate 3′-hydroxylase (C3′H), exhibits severe dwarfism and sterility. To better understand the impact of perturbation of phenylpropanoid metabolism on plant growth, we generated a chemically inducible C3′H expression construct and transformed it into the ref8 mutant. Application of dexamethasone to these plants greatly alleviates the dwarfism and sterility and substantially reverses the biochemical phenotypes of ref8 plants, including the reduction of lignin content and hyperaccumulation of flavonoids and p-coumarate esters. Induction of C3′H expression at different developmental stages has distinct impacts on plant growth. Although early induction effectively restored the elongation of primary inflorescence stem, application to 7-week-old plants enabled them to produce new rosette inflorescence stems. Examination of hypocotyls of these plants revealed normal vasculature in the newly formed secondary xylem, presumably restoring water transport in the mutant. The ref8 mutant accumulates higher levels of salicylic acid than the wild type, but depletion of this compound in ref8 did not relieve the mutant’s growth defects, suggesting that the hyperaccumulation of salicylic acid is unlikely to be responsible for dwarfism in this mutant. PMID:24381065

  11. Proline improves copper tolerance in chickpea (Cicer arietinum).

    PubMed

    Singh, Vijeta; Bhatt, Indu; Aggarwal, Anjali; Tripathi, Bhumi Nath; Munjal, Ashok Kumar; Sharma, Vinay

    2010-09-01

    The present study suggests the involvement of proline in copper tolerance of four genotypes of Cicer arietinum (chickpea). Based on the data of tolerance index and lipid peroxidation, the order for copper tolerance was as follows: RSG 888 > CSG 144 > CSG 104 > RSG 44 in the selected genotypes. The basis of differential copper tolerance in chickpea genotypes was characterized by analyzing, antioxidant enzymes (superoxide dismutase, ascorbated peroxidase and catalase), phytochelatins, copper uptake, and proline accumulation. Chickpea genotypes showed stimulated superoxide dismutase activity at all tested concentrations of copper, but H(2)O(2) decomposing enzymes especially; ascorbate peroxidase did not increase with 25 and 50 microM copper treatments. Catalase activity, however, increased at lower copper concentrations but failed to stimulate at 50 microM copper. Such divergence in responses of these enzymes minimizes their importance in protecting chickpea against copper stress. The sensitive genotypes showed greater enhancement of phytochelatins than that of tolerant genotypes. Hence, the possibility of phytochelatins in improving copper tolerance in the test plant is also excluded. Interestingly, the order of proline accumulation in the chickpea genotypes (RSG 888 > CSG 144 > CSG 104 > RSG 44) was exactly similar to the order of copper tolerance. Based on hyperaccumulation of proline in tolerant genotype (RSG 44) and the reduction and improvement of lipid peroxidation and tolerance index, respectively, by proline pretreatment, we conclude that hyperaccumulation of proline improves the copper tolerance in chickpea.

  12. Enhanced phytoremediation of cadmium polluted water through two aquatic plants Veronica anagallis-aquatica and Epilobium laxum.

    PubMed

    Ahmad, Ayaz; Hadi, Fazal; Ali, Nasir; Jan, Amin Ullah

    2016-09-01

    Toxic metal-contaminated water is a major threat to sustainable agriculture and environment. Plants have the natural ability to absorb and concentrate essential elements in its tissues from water solution, and this ability of plants can be exploited to remove heavy/toxic metals from the contaminated water. For this purpose, two plants Veronica anagallis-aquatica and Epilobium laxum were hydroponically studied. The effect of different fertilizers (NPK) and plant growth regulators (GA3 and IAA) were evaluated on growth, biomass, free proline, phenolics, and chlorophyll contents, and their role in Cd phytoaccumulation was investigated. Results showed that in both plants, fertilizer addition to media (treatment T4) produced the highest significant increase in growth, biomass (fresh and dry), cadmium concentration, proline, phenolics, and chlorophyll concentrations. The significant effect of GA3 in combination with NPK foliar spray (treatment T12) was observed on most of the growth parameters, Cd concentration, and proline and phenolic contents of the plants. The free proline and total phenolics showed positive correlation with cadmium concentration within plant tissues. Proline showed significantly positive correlation with phenolic contents of root and shoot. Veronica plant demonstrated the hyperaccumulator potential for cadmium as bioconcentration factor (BCF >1) which was much higher than 1, while Epilobium plant showed non-hyperaccumulator potential. It is recommended for further study to investigate the role of Veronica plant for other metals and to study the role of phenolics and proline contents in heavy metal phytoextraction by various plant species.

  13. Molecular Genetics of Metal Detoxification: Prospects for Phytoremediation

    SciTech Connect

    Ow, David W. ow@pgec.ams.usda.gov

    2000-09-01

    Unlike compounds that can be broken down, the remediation of most heavy metals and radionuclides requires physical extraction from contaminated sources. Plants can extract inorganics, but effective phytoextraction requires plants that produce high biomass, grow rapidly and possess high capacity-uptake for the inorganic substance. Either hyperaccumulator plants must be bred for increased growth and biomass or hyperaccumulation traits must be engineered into fast growing, high biomass plants. This latter approach requires fundamental knowledge of the molecular mechanisms in the uptake and storage of inorganics. Much has been learned in recent years on how plants and certain fungi chelate and transport selected heavy metals. This progress has been facilitated by the use of Schizosaccharomyces pombe as a model system. The use of a model organism for study permits rapid characterization of the molecular process. As target genes are identified in a model organism, their sequences can be modified for expression in a heterologous host or aid in the search of homologous genes in more complex organisms. Moreover, as plant nutrient uptake is intrinsically linked to the association with rhizospheric fungi, elucidating metal sequestration in this fungus permits additional opportunities for engineering rhizospheric microbes to assist in phytoextraction.

  14. Zinc tolerance and accumulation in stable cell suspension cultures and in vitro regenerated plants of the emerging model plant Arabidopsis halleri (Brassicaceae).

    PubMed

    Vera-Estrella, Rosario; Miranda-Vergara, Maria Cristina; Barkla, Bronwyn J

    2009-03-01

    Arabidopsis halleri is increasingly employed as a model plant for studying heavy metal hyperaccumulation. With the aim of providing valuable tools for studies on cellular physiology and molecular biology of metal tolerance and transport, this study reports the development of successful and highly efficient methods for the in vitro regeneration of A. halleri plants and production of stable cell suspension lines. Plants were regenerated from leaf explants of A. halleri via a three-step procedure: callus induction, somatic embryogenesis and shoot development. Efficiency of callus proliferation and regeneration depended on the initial callus induction media and was optimal in the presence of 1 mg L(-1) 2,4-dichlorophenoxyacetic acid, and 0.05 mg L(-1) benzylaminopurine. Subsequent shoot and root regeneration from callus initiated under these conditions reached levels of 100% efficiency. High friability of the callus supported the development of cell suspension cultures with minimal cellular aggregates. Characterization of regenerated plants and cell cultures determined that they maintained not only the zinc tolerance and requirement of the whole plant but also the ability to accumulate zinc; with plants accumulating up to 50.0 micromoles zinc g(-1) FW, and cell suspension cultures 30.9 micromoles zinc g(-1) DW. Together this work will provide the experimental basis for furthering our knowledge of A. halleri as a model heavy metal hyperaccumulating plant.

  15. Accumulation of cadmium and zinc in Evodiopanax innovans.

    PubMed

    Takenaka, Chisato; Kobayashi, Motoharu; Kanaya, Shotaro

    2009-12-01

    The use of tree species for phytoremediation of contaminated soil offers the advantage of a large biomass in which to store contaminants. We investigated the cadmium (Cd) and zinc (Zn) accumulation ability of Evodiopanax innovans, a common deciduous tree species belonging to the Araliaceae family and widely found in secondary forests in Japan. Sampling was conducted at an old silver mine. Leaf samples were collected from nine tree species, including E. innovans. The seasonal variation of metal concentrations in the leaves and the detailed distribution of metals in the leaves and twigs of E. innovans were measured. We also analyzed the contents of organic acids in the leaves. The highest concentration of Cd in the leaves of E. innovans was 118 μg/g, which exceeds the threshold level for being considered a Cd hyperaccumulator (100 μg/g). For Zn, the highest value was 1040 μg/g in leaves, which is less than required to qualify as a Zn hyperaccumulator. Both Cd and Zn were found to accumulate in the petioles and veins of leaves and the bark of twigs. Since the oxalic acid content of leaves showed a weak correlation with Cd concentration, oxalic acid may play an important role in the accumulation of Cd. Taking both the Cd concentration level and the biomass of this woody plant into consideration, it may be possible to use E. innovans for the phytoremediation of Cd-contaminated soils.

  16. In vivo micro X-ray analysis utilizing synchrotron radiation of the gametophytes of three arsenic accumulating ferns, Pteris vittata L., Pteris cretica L. and Athyrium yokoscense, in different growth stages.

    PubMed

    Kashiwabara, Teruhiko; Mitsuo, Sakiko; Hokura, Akiko; Kitajima, Nobuyuki; Abe, Tomoko; Nakai, Izumi

    2010-04-01

    In vivo X-ray analysis utilizing synchrotron radiation was performed to investigate the distribution and oxidation state of arsenic in the gametophytes of two hyperaccumulators, Pteris vittata L. and Pteris cretica L., and an arsenic-accumulating fern, Athyrium yokoscense in the several growth stages from germination. The distribution of arsenic in P. vittata changed through the development of the plant tissues as follows. In two-week-old gametophyte, arsenic was mainly present along the rhizoid. In the one-month-old gametophyte with reproductive organs, arsenic was accumulating uniformly in the sheet of cells, except in the reproductive area. After fertilization, arsenic was observed in the aboveground part of the sporophyte structures. P. cretica and A. yokoscense showed different distributions, respectively. P. cretica showed an accumulation of arsenic in the reproductive area, in contrast to P. vittata, before fertilization, while arsenic was observed in the aboveground part of the sporophyte after fertilization. A. yokoscense showed an accumulation of arsenic along the rhizoids before fertilization, while it was present mainly along the roots of the sporophyte after fertilization. Reduced arsenic (As(iii)) was observed in all stages and in all tissues of P. vittata gametophytes. Further, a reduction of arsenic was commonly observed among the three ferns, although arsenic was bounded to sulfur in A. yokoscense. These findings may be related to their own reproductive process or to detoxification mechanism. They provide basic information for the understanding of arsenic hyperaccumulation in these ferns, leading to further application of these gametophyte systems.

  17. Characterization of phytase from three ferns with differing arsenic tolerance.

    PubMed

    Tu, S; Ma, L; Rathinasabapathi, B

    2011-02-01

    Phytase is involved in many physiological activities in plants including phosphorus metabolism and stress response. The effects of arsenic on phytase activities in arsenic-hyperaccumulator Pteris vittata were determined. Two arsenic-sensitive ferns (Pteris ensiformis and Nephrolepis exaltata) were included for comparison purpose. Fern phytase was extracted with Tris-HCl buffer (pH 7.6) followed by ammonium sulfate partial purification to characterize its properties and arsenic stress responses. The phytase showed an optimum pH of 5.0 and temperature of 40 °C except for P. vittata with 40-70 °C. Phytase from P. vittata was the first plant-phytase showing high heat resistance with no loss of activity by heating it at 70 °C, which may have application in feed industry. Phytase activity was inhibited by arsenate but not by arsenite. The fact that P. vittata phytase was the most heat-tolerant (40-70 °C) and had the highest resistance to arsenate among the three ferns suggest that phytase may play a role in arsenic detoxification and arsenic hyperaccumulation in P. vittata.

  18. Arsenic in the rhizosphere soil solution of ferns.

    PubMed

    Wei, Chaoyang; Zheng, Huan; Yu, Jiangping

    2012-12-01

    The aim of this study was to explore the evidence of arsenic hyperaccumulation in plant rhizosphere solutions. Six common fern plants were selected and grown in three types of substrate: arsenic (As) -tailings, As-spiked soil, and soil-As-tailing composites. A rhizobox was designed with an in-situ collection of soil solutions to analyze changes in the As concentration and valence as well as the pH, dissolved organic carbon (DOC) and total nitrogen (TN). Arsenite composed less than 20% of the total As, and As depletion was consistent with N depletion in the rhizosphere solutions of the various treatments. The As concentrations in the rhizosphere and non-rhizosphere solutions in the presence of plants were lower than in the respective controls without plants, except for in the As-spiked soils. The DOC concentrations were invariably higher in the rhizosphere versus non-rhizosphere solutions from the various plants; however, no significant increase in the DOC content was observed in Pteris vittata, in which only a slight decrease in pH appeared in the rhizosphere compared to non-rhizosphere solutions. The results showed that As reduction by plant roots was limited, acidification-induced solubilization was not the mechanism for As hyperaccumulation.

  19. Co-cropping for phyto-separation of zinc and potassium from sewage sludge.

    PubMed

    Wu, Qi-Tang; Hei, Liang; Wong, J W C; Schwartz, Christophe; Morel, Jean-Louis

    2007-08-01

    The use of sewage sludge as a fertilizer and soil amendment has resulted in high concentrations of heavy metals in the soil limiting its use. The present study was carried out to find the possibility of phyto-separating toxic and beneficial elements from the sludge using suitable plants. Of the five plants tested the hyperaccumulator Sedum alfredii H achieved the greatest removal of Zn, while shoots of Alocasia marorrhiza accumulated high content of K. Co-cropping these two plants on the sludge verified the previous observations on A. marorrhiza and the shoots of this plant could accumulate more than 120 g K kg(-1) dry matter in the median growth stage. Zn hyperaccumulated in Sedum's shoots to an extent more than 10 g kg(-1) dry matter; K concentrated five to ten times in the Alocasia's shoots which could be used as a good organic-K-fertilizer. Hence, the two elements were simultaneously phytoseparated and could be recycled. Furthermore, cultivation of plants in the sludge resulted in significant decreases in total Zn but kept the favorable agronomic characteristics of the sludge material, such as pH, organic matter content, and NPK concentrations and ameliorated its biological stability. These results suggest that simultaneous phyto-separation of toxic and beneficial elements from sewage sludge are possible by co-cropping using specific plants without the input of any chemicals.

  20. Metabolic phenotypes of Saccharomyces cerevisiae mutants with altered trehalose 6-phosphate dynamics.

    PubMed

    Walther, Thomas; Mtimet, Narjes; Alkim, Ceren; Vax, Amélie; Loret, Marie-Odile; Ullah, Azmat; Gancedo, Carlos; Smits, Gertien J; François, Jean Marie

    2013-09-01

    In Saccharomyces cerevisiae, synthesis of T6P (trehalose 6-phosphate) is essential for growth on most fermentable carbon sources. In the present study, the metabolic response to glucose was analysed in mutants with different capacities to accumulate T6P. A mutant carrying a deletion in the T6P synthase encoding gene, TPS1, which had no measurable T6P, exhibited impaired ethanol production, showed diminished plasma membrane H⁺-ATPase activation, and became rapidly depleted of nearly all adenine nucleotides which were irreversibly converted into inosine. Deletion of the AMP deaminase encoding gene, AMD1, in the tps1 strain prevented inosine formation, but did not rescue energy balance or growth on glucose. Neither the 90%-reduced T6P content observed in a tps1 mutant expressing the Tps1 protein from Yarrowia lipolytica, nor the hyperaccumulation of T6P in the tps2 mutant had significant effects on fermentation rates, growth on fermentable carbon sources or plasma membrane H⁺-ATPase activation. However, intracellular metabolite dynamics and pH homoeostasis were strongly affected by changes in T6P concentrations. Hyperaccumulation of T6P in the tps2 mutant caused an increase in cytosolic pH and strongly reduced growth rates on non-fermentable carbon sources, emphasizing the crucial role of the trehalose pathway in the regulation of respiratory and fermentative metabolism.

  1. Vitamin B2 as a virulence factor in Pseudogymnoascus destructans skin infection

    PubMed Central

    Flieger, Miroslav; Bandouchova, Hana; Cerny, Jan; Chudíčková, Milada; Kolarik, Miroslav; Kovacova, Veronika; Martínková, Natália; Novák, Petr; Šebesta, Ondřej; Stodůlková, Eva; Pikula, Jiri

    2016-01-01

    Pathogenic and non-pathogenic related microorganisms differ in secondary metabolite production. Here we show that riboflavin overproduction by a fungal pathogen and its hyperaccumulation in affected host tissue exacerbates a skin infection to necrosis. In white-nose syndrome (WNS) skin lesions caused by Pseudogymnoascus destructans, maximum riboflavin concentrations reached up to 815 μg ml−1, indicating bioaccumulation and lack of excretion. We found that high riboflavin concentrations are cytotoxic under conditions specific for hibernation, affect bats’ primary fibroblasts and induce cell detachment, loss of mitochondrial membrane potential, polymerization of cortical actin, and cell necrosis. Our results explain molecular pathology of WNS, where a skin infection becomes fatal. Hyperaccumulation of vitamin B2 coupled with reduced metabolism and low tissue oxygen saturation during hibernation prevents removal of excess riboflavin in infected bats. Upon reperfusion, oxygen reacts with riboflavin resulting in dramatic pathology after arousal. While multiple molecules enable invasive infection, riboflavin-associated extensive necrosis likely contributes to pathophysiology and altered arousal pattern in infected bats. Bioaccumulation of a vitamin under natural infection represents a novel condition in a complex host-pathogen interplay. PMID:27620349

  2. On the formation and extent of uptake of silver nanoparticles by live plants

    NASA Astrophysics Data System (ADS)

    Harris, Andrew T.; Bali, Roza

    2008-04-01

    In this work we investigate the limits of uptake of metallic silver by two common metallophytes, Brassica juncea (BJ) and Medicago sativa (MS) and assess the form and distribution of the metal once sequestered by the plants. BJ accumulated up to 12.4 wt.% silver when exposed to an aqueous substrate containing 1,000 ppm AgNO3 for 72 h, however silver uptake was largely independent of exposure time and substrate silver concentration. MS accumulated up to 13.6 wt.% silver when exposed to an aqueous substrate containing 10,000 ppm AgNO3 for 24 h. In contrast to BJ there was a general trend for MS showing an increase in metal uptake with a corresponding increase in the substrate metal concentration and exposure time. In both cases the silver was stored as discrete nanoparticles, with a mean size of ˜50 nm. According to the hyperaccumulation definition of Brooks et al. (Brooks RR, Chambers MF, Nicks LJ, Robinson BH (1998) Phytomining. Trends Plant Sci 3:359-362), this is the first report of the hyperaccumulation of silver in any plant species.

  3. A Transcriptomic Network Underlies Microstructural and Physiological Responses to Cadmium in Populus × canescens1[C][W

    PubMed Central

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

    2013-01-01

    Bark tissue of Populus × canescens can hyperaccumulate cadmium, but microstructural, transcriptomic, and physiological response mechanisms are poorly understood. Histochemical assays, transmission electron microscopic observations, energy-dispersive x-ray microanalysis, and transcriptomic and physiological analyses have been performed to enhance our understanding of cadmium accumulation and detoxification in P. × canescens. Cadmium was allocated to the phloem of the bark, and subcellular cadmium compartmentalization occurred mainly in vacuoles of phloem cells. Transcripts involved in microstructural alteration, changes in nutrition and primary metabolism, and stimulation of stress responses showed significantly differential expression in the bark of P. × canescens exposed to cadmium. About 48% of the differentially regulated transcripts formed a coregulation network in which 43 hub genes played a central role both in cross talk among distinct biological processes and in coordinating the transcriptomic regulation in the bark of P. × canescens in response to cadmium. The cadmium transcriptome in the bark of P. × canescens was mirrored by physiological readouts. Cadmium accumulation led to decreased total nitrogen, phosphorus, and calcium and increased sulfur in the bark. Cadmium inhibited photosynthesis, resulting in decreased carbohydrate levels. Cadmium induced oxidative stress and antioxidants, including free proline, soluble phenolics, ascorbate, and thiol compounds. These results suggest that orchestrated microstructural, transcriptomic, and physiological regulation may sustain cadmium hyperaccumulation in P. × canescens bark and provide new insights into engineering woody plants for phytoremediation. PMID:23530184

  4. Arsenic alters uptake and distribution of sulphur in Pteris vittata.

    PubMed

    Watanabe, Toshihiro; Kouho, Ran; Katayose, Tomo; Kitajima, Nobuyuki; Sakamoto, Naoya; Yamaguchi, Noriko; Shinano, Takuro; Yurimoto, Hisayoshi; Osaki, Mitsuru

    2014-01-01

    Low-molecular-weight thiol (LMWT) synthesis has been reported to be directly induced by arsenic (As) in Pteris vittata, an As hyperaccumulator. Sulphur (S) is a critical component of LMWTs. Here, the effect of As treatment on the uptake and distribution of S in P. vittata was investigated. In P. vittata grown under low S conditions, the presence of As in the growth medium enhanced the uptake of SO4(2-), which was used for LMWT synthesis in fronds. In contrast, As application did not affect SO4(2-) uptake in Nephrolepis exaltata, an As non-hyperaccumulator. Moreover, the isotope microscope system revealed that S absorbed with As accumulated locally in a vacuole-like organelle in epidermal cells, whereas S absorbed alone was distributed uniformly. These results suggest that S is involved in As transport and/or accumulation in P. vittata. X-ray absorption near-edge structure analysis revealed that the major As species in the fronds and roots of P. vittata were inorganic As(III) and As(V), respectively, and that As-LMWT complexes occurred as a minor species. Consequently, in case of As accumulation in P. vittata, S possibly acts as a temporary ligand for As in the form of LMWTs in intercellular and/or intracellular transport (e.g. vacuolar sequestration).

  5. Selenium accumulation by plants

    PubMed Central

    White, Philip J.

    2016-01-01

    Background Selenium (Se) is an essential mineral element for animals and humans, which they acquire largely from plants. The Se concentration in edible plants is determined by the Se phytoavailability in soils. Selenium is not an essential element for plants, but excessive Se can be toxic. Thus, soil Se phytoavailability determines the ecology of plants. Most plants cannot grow on seleniferous soils. Most plants that grow on seleniferous soils accumulate <100 mg Se kg–1 dry matter and cannot tolerate greater tissue Se concentrations. However, some plant species have evolved tolerance to Se, and commonly accumulate tissue Se concentrations >100 mg Se kg–1 dry matter. These plants are considered to be Se accumulators. Some species can even accumulate Se concentrations of 1000–15 000 mg Se kg–1 dry matter and are called Se hyperaccumulators. Scope This article provides an overview of Se uptake, translocation and metabolism in plants and highlights the possible genetic basis of differences in these between and within plant species. The review focuses initially on adaptations allowing plants to tolerate large Se concentrations in their tissues and the evolutionary origin of species that hyperaccumulate Se. It then describes the variation in tissue Se concentrations between and within angiosperm species and identifies genes encoding enzymes limiting the rates of incorporation of Se into organic compounds and chromosomal loci that might enable the development of crops with greater Se concentrations in their edible portions. Finally, it discusses transgenic approaches enabling plants to tolerate greater Se concentrations in the rhizosphere and in their tissues. Conclusions The trait of Se hyperaccumulation has evolved several times in separate angiosperm clades. The ability to tolerate large tissue Se concentrations is primarily related to the ability to divert Se away from the accumulation of selenocysteine and selenomethionine, which might be incorporated

  6. Heavy metals concentration in plants growing on mine tailings in Central Mexico.

    PubMed

    Franco-Hernández, M O; Vásquez-Murrieta, M S; Patiño-Siciliano, A; Dendooven, L

    2010-06-01

    Metal concentrations were measured in plants growing on heavily contaminated tailings from a mine active since about 1800 in San Luis Potosí (Mexico). Viguiera dentata (Cav.) Spreng., Parthenium bipinnatifidum (Ort.) Rollins, Flaveria angustifolia (Cav.) Pers., F. trinervia (Spreng.) C. Mohr. and Sporobolusindicus (L.) R. Br. were tolerant to high As, Cu, Pb and Zn concentrations. Of those, S.indicus excluded heavy metals from its shoots, while P. bipinnatifidum and F. angustifolia accumulated them. V. dentata and P. bipinnatifidum were accumulators of As, but not hyperaccumulators. It was found that V. dentata,P. bipinnatifidum, F. angustifolia, F. trinervia and S.indicus, could be used to vegetate soils contaminated with As, Cu, Pb and Zn. Ambrosiaartemisifolia could be used to remediate soils contaminated with Zn, S. amplexicaulis those with Cu and F. angustifolia and F. trinervia those with As, as they have a strong capacity to accumulate those metals.

  7. Applicability of Phytoextraction with Arabidopsis halleri ssp. gemmifera to Remediate Cd-contaminated Andisols

    NASA Astrophysics Data System (ADS)

    Kameyama, Koji; Tani, Shigeru; Sugawara, Reiko; Ishikawa, Yuichi

    The objective of this study was to investigate the applicability of phytoextraction with a Cd-hyperaccumulator plant (Arabidopsis halleri ssp. gemmifera) to remediate Cd-contaminated Andisols. Cd absorption potentials of this plant for Andisols were examined in pot experiments. Sequentially, phytoextraction durations for remediation of Cd-contaminated Andisols were calculated from the experimental data. The results were as follows: (1) Cd concentrations in the plant shoots ranged from 170-750 mgṡkg-1. (2) Cd absorption of the plant for Andisols with ALC (Autoclaved Lightweight aerated Concrete) was less than for Andisols without ALC. However, the plants absorbed the same amount of soil Cd extracted by 0.01 M HCl with or without ALC. (3) Calculations suggest that the applicability of phytoextraction with this plant is high for slightly contaminated Andisols. Therefore, phytoextraction with Arabidopsis halleri ssp. gemmifera may be a viable option for the remediation of Cd-contaminated Andisols.

  8. Nitrates and Glucosinolates as Strong Determinants of the Nutritional Quality in Rocket Leafy Salads

    PubMed Central

    Cavaiuolo, Marina; Ferrante, Antonio

    2014-01-01

    Rocket is an important leafy vegetable crop and a good source of antioxidants and anticancer molecules such as glucosinolates and other sulfur compounds. Rocket is also a hyper-accumulator of nitrates which have been considered for long time the main factors that cause gastro-intestinal cancer. In this review, the content of these compounds in rocket tissues and their levels at harvest and during storage are discussed. Moreover, the effect of these compounds in preventing or inducing human diseases is also highlighted. This review provides an update to all the most recent studies carried out on rocket encouraging the consumption of this leafy vegetable to reduce the risk of contracting cancer and other cardiovascular diseases. PMID:24736897

  9. Phytoremediation potential of Cd and Zn by wetland plants, Colocasia esculenta L. Schott., Cyperus malaccensis Lam. and Typha angustifolia L. grown in hydroponics.

    PubMed

    Chayapan, P; Kruatrachue, M; Meetam, M; Pokethitiyook, P

    2015-09-01

    Cadmium and zinc phytoremediation potential of wetland plants, Colocasia esculenta, Cyperus malaccensis, and Typha angustifolia, was investigated. Plants were grown for 15 days in nutrient solutions containing various concentrations of Cd (0, 5, 10, 20, 50 mg l(-1)) and Zn (0, 10, 20, 50, 100 mg l(-1)). T angustifolia was tolerant to both metals as indicated by high RGR when grown in 50 mg I(-1) Cd and 100 mg I(-1) Zn solutions. All these plants accumulated more metals in their underground parts and > 100 mg kg(-1) in their aboveground with TF values < 1. Only C. esculenta could be considered a Zn hyperaccumulator because it could concentrate > 10,000 mg kg(-1) in its aboveground parts with TF > 1. T angustifolia exhibited highest biomass production and highest Cd and Zn uptake, confirming that this plant is a suitable candidate for treating of Cd contaminated soil/sediments.

  10. Silicon in Imperata cylindrica (L.) P. Beauv: content, distribution, and ultrastructure.

    PubMed

    Rufo, Lourdes; Franco, Alejandro; de la Fuente, Vicenta

    2014-07-01

    Silicon concentration, distribution, and ultrastructure of silicon deposits in the Poaceae Imperata cylindrica (L.) P. Beauv. have been studied. This grass, known for its medicinal uses and also for Fe hyperaccumulation and biomineralization capacities, showed a concentration of silicon of 13,705 ± 9,607 mg/kg dry weight. Silicon was found as an important constituent of cell walls of the epidermis of the whole plant. Silica deposits were found in silica bodies, endodermis, and different cells with silicon-collapsed lumen as bulliforms, cortical, and sclerenchyma cells. Transmission electron microscope observations of these deposits revealed an amorphous material of an ultrastructure similar to that previously reported in silica bodies of other Poaceae.

  11. Biological and ecophysiological reactions of white wall rocket (Diplotaxis erucoides L.) grown on sewage sludge compost.

    PubMed

    Korboulewsky, Nathalie; Bonin, Gilles; Massiani, Catherine

    2002-01-01

    We studied the effects of sewage sludge compost on white wall rocket (Diplotaxis erucoides L.) compared with mineral fertilization and control (without any fertilizer) in a greenhouse experiment. The plants grown on the compost-amended soil showed a different growth dynamic: a significant delay in flowering and a bigger root system. Both the compost and the fertilization treatments increased biomass and seed yield. Heavy metal (Cu, Cd, Zn, Ni) distribution within the plant was in the following order: roots > leaves > stems, except for zinc which was homogeneously distributed. The balance of mineral nutrition was not affected by treatments. Zinc was the trace element which was most taken up. Unlike many species of Brassicaceae, white wall rocket is not a hyperaccumulator. Although sewage sludge compost improved plant growth, delay in flowering shows that it is necessary to take precautions when spreading sewage sludge in natural areas.

  12. The Tie-dyed pathway promotes symplastic trafficking in the phloem

    PubMed Central

    Baker, R. Frank; Slewinski, Thomas L.; Braun, David M.

    2013-01-01

    The tie-dyed1 (tdy1) and tdy2 mutants of maize exhibit leaf regions with starch hyperaccumulation and display unusual genetic interactions, suggesting they function in the same physiological process. Tdy2 encodes a putative callose synthase and is expressed in developing vascular tissues of immature leaves. Radiolabelling experiments and transmission electron microscopy (TEM) revealed symplastic trafficking within the phloem was perturbed at the companion cell/sieve element interface. Here, we show that as reported for tdy2 mutants, tdy1 yellow leaf regions display an excessive oil-droplet phenotype in the companion cells. Based on the proposed function of Tdy2 as a callose synthase, our previous work characterizing Tdy1 as a novel, transmembrane-localized protein, and the present findings, we speculate how TDY1 and TDY2 might interact to promote symplastic transport of both solutes and developmentally instructive macromolecules during vascular development at the companion cell/sieve element interface. PMID:23603956

  13. Characterization and multiplexing of 21 microsatellite markers for the herb Noccaea caerulescens (Brassicaceae)1

    PubMed Central

    Mousset, Mathilde; Flaven, Elodie; Justy, Fabienne; Pouzadoux, Juliette; Gode, Cécile; Pauwels, Maxime; Gonneau, Cédric

    2015-01-01

    Premise of the study: Multiplexed microsatellite markers were developed for population genetic studies in the pseudometallophyte Noccaea caerulescens (Brassicaceae), a model species to investigate metal tolerance and hyperaccumulation in higher plants. Methods and Results: Microsatellite loci were isolated through pyrosequencing of an enriched DNA library. Three multiplexes combining four previously published and 17 newly designed markers were developed. The new markers were screened in metallicolous and nonmetallicolous populations from southern France. The total number of alleles per locus ranged from five to 18. The observed heterozygosity per locus and per population ranged from 0 to 0.83, and expected heterozygosity ranged from 0 to 0.89. Conclusions: The investigated loci showed reasonable to high levels of polymorphism at the regional scale. The multiplex set should be helpful in investigating genetic diversity, population structure, and demographic history in N. caerulescens at various spatial scales. PMID:26697274

  14. The deubiquitinating enzyme USP1 regulates the Fanconi anemia pathway.

    PubMed

    Nijman, Sebastian M B; Huang, Tony T; Dirac, Annette M G; Brummelkamp, Thijn R; Kerkhoven, Ron M; D'Andrea, Alan D; Bernards, René

    2005-02-04

    Protein ubiquitination and deubiquitination are dynamic processes implicated in the regulation of numerous cellular pathways. Monoubiquitination of the Fanconi anemia (FA) protein FANCD2 appears to be critical in the repair of DNA damage because many of the proteins that are mutated in FA are required for FANCD2 ubiquitination. By screening a gene family RNAi library, we identify the deubiquitinating enzyme USP1 as a novel component of the Fanconi anemia pathway. Inhibition of USP1 leads to hyperaccumulation of monoubiquitinated FANCD2. Furthermore, USP1 physically associates with FANCD2, and the proteins colocalize in chromatin after DNA damage. Finally, analysis of crosslinker-induced chromosomal aberrations in USP1 knockdown cells suggests a role in DNA repair. We propose that USP1 deubiquitinates FANCD2 when cells exit S phase or recommence cycling after a DNA damage insult and may play a critical role in the FA pathway by recycling FANCD2.

  15. Phytoextraction of Cd and Zn as single or mixed pollutants from soil by rape (Brassica napus).

    PubMed

    Cojocaru, Paula; Gusiatin, Zygmunt Mariusz; Cretescu, Igor

    2016-06-01

    This paper analyses the capacity of the rape (Brassica napus) to extract Cd and Zn from the soil and the effect of these metals on the morphometric parameters of the plant (length, weight, surface area, fractal dimension of leaves). Rape plants were mostly affected by the combined toxicity of the Cd and Zn mixture that caused a significant reduction in the rate of seed germination, the plant biomass quantity and the fractal dimension. In the case of Cd soil pollution, the bioaccumulation factor (BAF), bioaccumulation coefficient (BAC) as well as the heavy metal root-to-stalk translocation factor (TF) were determined. The results showed that B. napus had a great potential as a cadmium hyperaccumulator but not as an accumulator of Zn or Cd + Zn mixture. The efficiency of phytoextraction rape was 0.8-1.22 % for a soil heavily polluted with cadmium.

  16. Reduction of Health Risks Due to Chromium(VI)Using Mesquite: A Potential Cr Phytoremediator

    SciTech Connect

    Gardea-Torresdey, Jorge L.; Aldrich, Mary V.; Peralta-Videa, Jose R.; Parsons, Jason G.

    2004-03-29

    Chromium is a transition metal extensively used in industry. Cr mining and industrial operations account for chromium wastes at Superfund sites in the United States. A study was performed to investigate the possibility of using mesquite (Prosopis spp.), which is an indigenous desert plant species, to remove Cr from contaminated sites. In this study, mesquite plants were grown in an agar-based medium containing 75 mg L-1 and 125 mg L-1 of Cr(VI). The Cr content of leaf tissue (992 mg kg-1 of dry weight, from 125 mg L-1 of Cr(VI)) indicated that mesquite could be classified as a chromium hyperaccumulator. X-ray absorption spectroscopy (XAS) studies performed to experimental samples showed that mesquite roots absorbed some of the supplied Cr(VI). However, the data analyses of plant tissues demonstrated that the absorbed Cr(VI) was fully reduced to Cr(III) in the leaf tissue.

  17. Speciation of nickel by HPLC-UV/MS in pea nodules.

    PubMed

    Cacho, C; Brito, B; Palacios, J; Pérez-Conde, C; Cámara, C

    2010-11-15

    A new and sensitive methodology based on normal phase HPLC has been developed for the speciation of nickel in low-complexity plant extracts. The method combines a silica stationary phase column, a 9:1 (v/v) hexane:ethanol mixture as mobile phase, and the detection of nickel complexes by either UV or MS. The developed methodology was applied to the speciation of nickel complexes in the cytoplasm of pea root nodules. Results obtained indicate that nickel citrate and nickel malate accounts for 99% of nickel present in pea nodule cytoplasm fraction. The low detection limit of the method (<0.2 nM) enables nickel speciation in non-hyperaccumulator plants.

  18. Metal and metalloid containing natural products and a brief overview of their applications in biology, biotechnology and biomedicine.

    PubMed

    Dias, Daniel A; Kouremenos, Konstantinos A; Beale, David J; Callahan, Damien L; Jones, Oliver A H

    2016-02-01

    Bioinorganic natural product chemistry is a relatively unexplored but rapidly developing field with enormous potential for applications in biology, biotechnology (especially in regards to nanomaterial development, synthesis and environmental cleanup) and biomedicine. In this review the occurrence of metals and metalloids in natural products and their synthetic derivatives are reviewed. A broad overview of the area is provided followed by a discussion on the more common metals and metalloids found in natural sources, and an overview of the requirements for future research. Special attention is given to metal hyperaccumulating plants and their use in chemical synthesis and bioremediation, as well as the potential uses of metals and metalloids as therapeutic agents. The potential future applications and development in the field are also discussed.

  19. Polycyclic aromatic hydrocarbons in soils and lower-layer plants of the southern shrub tundra under technogenic conditions

    NASA Astrophysics Data System (ADS)

    Yakovleva, E. V.; Gabov, D. N.; Beznosikov, V. A.; Kondratenok, B. M.

    2014-06-01

    In soils and plants of the southern shrub tundra, 15 polycyclic aromatic hydrocarbons (PAHs) have been detected by high-performance liquid chromatography. Polyarenes in emissions, soil organic horizons, and plants mainly include low-molecular-weight PAHs: naphthalene, fluorine, and pyrene. The contents of the total PAHs in soils and plants exceed the background levels by 3-5 times. The distribution of polyarenes among the organs of the studied plants is nonuniform and depends on the plant species and technogenic load on the area. The studied plants include both hyperaccumulators of polyarenes ( Pleurozium schreberi) and indicators of PAHs in the soil ( Polytrichum commune). Pleurozium schreberi is the most abundant species in the areas under study, and it accumulates the largest mass fraction of PAHs. The differences in the accumulation of PAHs by the plants of the tundra and taiga zones have been revealed.

  20. EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana.

    PubMed

    Wang, Hong-qi; Lu, Si-jin; Li, Hua; Yao, Zhi-hua

    2007-01-01

    Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils. Bidens maximowicziana is a new Pb hyperaccumulator, which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb. The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues. The Pb distribution order in the B. maximowicziana was: leaf > stem > root. The effect of amendments on phytoremediation was also studied. The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application. Compared with CK (control check), EDTA application promoted translocation of Pb to overground parts of the plant. The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg. This research demonstrated that B. maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil, especially, combination with EDTA.

  1. Zinc accumulation and synthesis of ZnO nanoparticles using Physalis alkekengi L.

    PubMed

    Qu, Jiao; Yuan, Xing; Wang, Xinhong; Shao, Peng

    2011-07-01

    A field survey and greenhouse experiments were conducted using Physalis alkekengi L. to investigate strategies of phytoremediation. In addition, ZnO nanoparticles were synthesized using P. alkekengi. P. alkekengi plants grew healthily at Zn levels from 50 to 5000 mg kg(-1) in soils. The plants incorporated Zn into their aerial parts (with mean dry weight values of 235-10,980 mg kg(-1)) and accumulated biomass (with a mean dry weight of 25.7 g plant(-1)) during 12 weeks. The synthesized ZnO nanoparticles showed a polydisperse behavior and had a mean size of 72.5 nm. The results indicate that P. alkekengi could be used for the remediation of zinc-contaminated soils. Moreover, the synthetic method of synthesizing ZnO nanoparticles from Zn hyperaccumulator plants constitutes a new insight into the recycling of metals in plant sources.

  2. Efficiency of repeated phytoextraction of cadmium and zinc from an agricultural soil contaminated with sewage sludge.

    PubMed

    Luo, Kai; Ma, Tingting; Liu, Hongyan; Wu, Longhua; Ren, Jing; Nai, Fengjiao; Li, Rui; Chen, Like; Luo, Yongming; Christie, Peter

    2015-01-01

    Long-term application of sewage sludge resulted in soil cadmium (Cd) and zinc (Zn) contamination in a pot experiment conducted to phytoextract Cd/Zn repeatedly using Sedum plumbizincicola and Apium graceolens in monoculture or intercropping mode eight times. Shoot yields and soil physicochemical properties changed markedly with increasing number of remediation crops when the two plant species were intercropped compared with the unplanted control soil and the two monoculture treatments. Changes in soil microbial indices such as average well colour development, soil enzyme activity and soil microbial counts were also significantly affected by the growth of the remediation plants, especially intercropping with S. plumbizincicola and A. graveolens. The higher yields and amounts of Cd taken up indicated that intercropping of the hyperaccumulator and the vegetable species may be suitable for simultaneous agricultural production and soil remediation, with larger crop yields and higher phytoremediation efficiencies than under monoculture conditions.

  3. EDTA enhanced phytoremediation of copper contaminated soils using chickpea (Cicer aeritinum L.).

    PubMed

    Kambhampati, Murty S; Vu, Van Tu

    2013-09-01

    The goal of this research was to determine whether or not chickpea (Cicer arietinum L.), commonly known as Garbanzo beans, is a hyper accumulator for copper (Cu) in contaminated soils amended with EDTA. Statistical analysis (2 tailed Pearson Correlation) revealed significant correlations between: Translocation index and stem biomass (r = 0.859**; p < 0.01); Tolerance index and stem biomass (r = 0.762**; p < 0.01); and bioconcentration factor of stem/soil and soil Cu concentration (r = -0.545*; p < 0.05). Therefore, C. arietinum seems to be a cost-effective and environmentally friendly hyperaccumulator for Cu at 100 ppm Cu and 10 mM EDTA.

  4. Combined mild soil washing and compost-assisted phytoremediation in treatment of silt loams contaminated with copper, nickel, and chromium.

    PubMed

    Sung, Menghau; Lee, Chi-Yi; Lee, Suen-Zone

    2011-06-15

    A new soil remediation option, combining the soil washing process using pure water followed by the compost-assisted phytoextraction, is evaluated using silt loams contaminated with plating wastewater containing Cu, Ni, and Cr. Plants utilized in this study are the rapeseeds, sunflowers, tomatoes, and soapworts. Phytoextraction operation was carried out in pot experiments over a period of 4 months. Metal concentrations in roots and shoots of plants were analyzed upon completion of each pot experiment. Hypothesis testing was employed in assessing the significance of difference in the experimental data. Results indicated that the rapeseed, a hyperaccumulator, is most effective in extracting metals from the compost-amended silt loams. The fast-growing sunflowers and tomatoes are comparable to rapeseeds in accumulating metals despite their relatively low metal concentrations in tissues. Bioaccumulation coefficients obtained for all plants are less than one, indicating that phytostabilization rather than phytoextraction is the dominant mechanism at this simulated final-phase condition.

  5. The tolerance efficiency of Panicum maximum and Helianthus annuus in TNT-contaminated soil and nZVI-contaminated soil.

    PubMed

    Jiamjitrpanich, Waraporn; Parkpian, Preeda; Polprasert, Chongrak; Laurent, François; Kosanlavit, Rachain

    2012-01-01

    This study was designed to compare the initial method for phytoremediation involving germination and transplantation. The study was also to determine the tolerance efficiency of Panicum maximum (Purple guinea grass) and Helianthus annuus (Sunflower) in TNT-contaminated soil and nZVI-contaminated soil. It was found that the transplantation of Panicum maximum and Helianthus annuus was more suitable than germination as the initiate method of nano-phytoremediation potting test. The study also showed that Panicum maximum was more tolerance than Helianthus annuus in TNT and nZVI-contaminated soil. Therefore, Panicum maximum in the transplantation method should be selected as a hyperaccumulated plant for nano-phytoremediation potting tests. Maximum tolerance dosage of Panicum maximum to TNT-concentration soil was 320 mg/kg and nZVI-contaminated soil was 1000 mg/kg in the transplantation method.

  6. Repressor-mediated tissue-specific gene expression in plants

    DOEpatents

    Meagher, Richard B.; Balish, Rebecca S.; Tehryung, Kim; McKinney, Elizabeth C.

    2009-02-17

    Plant tissue specific gene expression by way of repressor-operator complexes, has enabled outcomes including, without limitation, male sterility and engineered plants having root-specific gene expression of relevant proteins to clean environmental pollutants from soil and water. A mercury hyperaccumulation strategy requires that mercuric ion reductase coding sequence is strongly expressed. The actin promoter vector, A2pot, engineered to contain bacterial lac operator sequences, directed strong expression in all plant vegetative organs and tissues. In contrast, the expression from the A2pot construct was restricted primarily to root tissues when a modified bacterial repressor (LacIn) was coexpressed from the light-regulated rubisco small subunit promoter in above-ground tissues. Also provided are analogous repressor operator complexes for selective expression in other plant tissues, for example, to produce male sterile plants.

  7. [Structure and function of heavy metal transporter P(1B)-ATPase in plant: a review].

    PubMed

    Zhang, Yuxiu; Zhang, Yuanya; Sun, Tao; Chai, Tuanyao

    2010-06-01

    The regulation of the heavy-metal accumulation in vivo for plant survival is very complex. The metal cation transporter plays key roles in the metabolic process. P(1B)-ATPases are the only subgroup of P-ATPases that contribute to heavy metal homeostasis presented in most organisms. Arabidopsis thaliana contains eight genes encoding P(1B)-ATPases. The current reports show that the functions of P(1B)-ATPases are involved in maintaining metal homeostasis, transporting and detoxification in plants. P(1B)-ATPases not only mediated metal ion mobilization and uptake in roots, but also contribute to the metal transport, storage and tolerance in shoots, especially in heavy metal hyperaccumulators. In this paper, we reviewed and discussed the evolution, classification, structure and function of P(1B)-ATPases in plants. HMAs-transgenic manipulation could be a feasible approach for phytoremediation and mineral nutrition fortification.

  8. The ABC Transporter ABCG1 Is Required for Suberin Formation in Potato Tuber Periderm[W

    PubMed Central

    Landgraf, Ramona; Smolka, Ulrike; Altmann, Simone; Eschen-Lippold, Lennart; Senning, Melanie; Sonnewald, Sophia; Weigel, Benjamin; Frolova, Nadezhda; Strehmel, Nadine; Hause, Gerd; Scheel, Dierk; Böttcher, Christoph; Rosahl, Sabine

    2014-01-01

    The lipid biopolymer suberin plays a major role as a barrier both at plant-environment interfaces and in internal tissues, restricting water and nutrient transport. In potato (Solanum tuberosum), tuber integrity is dependent on suberized periderm. Using microarray analyses, we identified ABCG1, encoding an ABC transporter, as a gene responsive to the pathogen-associated molecular pattern Pep-13. Further analyses revealed that ABCG1 is expressed in roots and tuber periderm, as well as in wounded leaves. Transgenic ABCG1-RNAi potato plants with downregulated expression of ABCG1 display major alterations in both root and tuber morphology, whereas the aerial part of the ABCG1-RNAi plants appear normal. The tuber periderm and root exodermis show reduced suberin staining and disorganized cell layers. Metabolite analyses revealed reduction of esterified suberin components and hyperaccumulation of putative suberin precursors in the tuber periderm of RNA interference plants, suggesting that ABCG1 is required for the export of suberin components. PMID:25122151

  9. Contaminated soils salinity, a threat for phytoextraction?

    PubMed

    Sirguey, Catherine; Ouvrard, Stéphanie

    2013-04-01

    Phytoremediation, given the right choice of plant, may be theoretically applicable to multi-contamination. Laboratory and some field trials have proven successful, but this ideal technique is in all cases dependent on plant growth ability on (generally) low-fertility soil or media. While contaminant concentration has often been proposed as an explanation for plant growth limitation, other factors, commonly occurring in industrial soils, such as salinity, should be considered. The present work highlights the fact that besides contaminants (trace elements and PAH), soil salinity may strongly affect germination and growth of the hyperaccumulator Noccaea caerulescens. Elevated concentrations of nitrate proved highly toxic for seed germination. At the growth stage the salt effect (sulfate) seemed less significant and the limited biomass production observed could be attributed mostly to organic contamination.

  10. Effect of lead on root growth

    PubMed Central

    Fahr, Mouna; Laplaze, Laurent; Bendaou, Najib; Hocher, Valerie; Mzibri, Mohamed El; Bogusz, Didier; Smouni, Abdelaziz

    2013-01-01

    Lead (Pb) is one of the most widespread heavy metal contaminant in soils. It is highly toxic to living organisms. Pb has no biological function but can cause morphological, physiological, and biochemical dysfunctions in plants. Plants have developed a wide range of tolerance mechanisms that are activated in response to Pb exposure. Pb affects plants primarily through their root systems. Plant roots rapidly respond either (i) by the synthesis and deposition of callose, creating a barrier that stops Pb entering (ii) through the uptake of large amounts of Pb and its sequestration in the vacuole accompanied by changes in root growth and branching pattern or (iii) by its translocation to the aboveground parts of plant in the case of hyperaccumulators plants. Here we review the interactions of roots with the presence of Pb in the rhizosphere and the effect of Pb on the physiological and biochemical mechanisms of root development. PMID:23750165

  11. Phytoremediation potential of paragrass--an in situ approach for chromium contaminated soil.

    PubMed

    Mohanty, Monalisa; Patra, Hemanta Kumar

    2012-09-01

    The present in situ phytoextraction approach uses paragrass (Brachiaria mutica (Forssk) Stapf) as a hyper accumulator for attenuation of chromium level in soil and mine waste water at South Kaliapani chromite mine area of Orissa. The bioconcentration factor (BCF) for Cr was maximum (0.334) in 100 days grown paragrass weeds. Transportation index (Ti) i.e. 6.16 and total accumulation rate (TAR) i.e. 8.2 mg kg(-1)day(-1) was maximum in 125 days old paragrass grown in Cr contaminated experimental cultivated plots. Cr bioaccumulation in roots was nearly 1000 times more than shoots. Paragrass showed luxuriant growth with massive fibrous roots when grown over Cr contaminated soils (11,170 mg/ kg dry soil). Cr bioaccumulation varies significantly with plant age, biomass and level of Cr contamination in irrigated mine waste water and soil. Paragrass could be used as hyperaccumulators as it showed rapid massive growth with a high tolerance to Cr.

  12. Nitrates and glucosinolates as strong determinants of the nutritional quality in rocket leafy salads.

    PubMed

    Cavaiuolo, Marina; Ferrante, Antonio

    2014-04-14

    Rocket is an important leafy vegetable crop and a good source of antioxidants and anticancer molecules such as glucosinolates and other sulfur compounds. Rocket is also a hyper-accumulator of nitrates which have been considered for long time the main factors that cause gastro-intestinal cancer. In this review, the content of these compounds in rocket tissues and their levels at harvest and during storage are discussed. Moreover, the effect of these compounds in preventing or inducing human diseases is also highlighted. This review provides an update to all the most recent studies carried out on rocket encouraging the consumption of this leafy vegetable to reduce the risk of contracting cancer and other cardiovascular diseases.

  13. Phytoremediation of Ionic and Methyl Mercury Pollution

    SciTech Connect

    Meagher, Richard B.

    2005-06-01

    Phytoremediation is defined as the use of plants to extract, resist, detoxify, and/or sequester toxic environmental pollutants. The long-term goal of the proposed research is to develop and test highly productive, field-adapted plant species that have been engineered for the phytoremediation of mercury. A variety of different genes, which should enable plants to clean mercury polluted sites are being tested as tools for mercury phytoremediation, first in model laboratory plants and then in potential field species. Several of these genes have already been shown to enhance mercury phytoremediation. Mercury pollution is a serious, world-wide problem affecting the health of human and wildlife populations. Environmentally, the most serious mercury threat is the production of methylmercury (CH3Hg+) by native bacteria at mercury contaminated wetland sites. Methylmercury is inherently more toxic than metallic (Hg(0)) or ionic (Hg(II)) mercury, and because methylmercury is prolifically biomagnified up the food chain, it poses the most immediate danger to animal populations. We have successfully engineered two model plants, Arabidopsis and tobacco, to use the bacterial merB gene to convert methylmercury to less toxic ionic mercury and to use the bacterial merA gene to further detoxify ionic mercury to the least toxic form of mercury, metallic mercury. Plants expressing both MerA and MerB proteins detoxify methylmercury in two steps to the metallic form. These plants germinate, grow, and set seed at normal growth rates on levels of methylmercury or ionic mercury that are lethal to normal plants. Our newest efforts involve engineering plants with several additional bacterial and plant genes that allow for higher levels of mercury resistance and mercury hyperaccumulation. The potential for these plants to hyperaccumulate mercury was further advanced by developing constitutive, aboveground, and root-specific gene expression systems. Our current strategy is to engineer plants to

  14. The engineered phytoremediation of ionic and methylmercury pollution 70054yr.2001.doc

    SciTech Connect

    Meagher, Richard B.

    2001-06-01

    Our long-term objective is to enable highly productive plant species to extract, resist, detoxify, and/or sequester toxic organic and heavy metal pollutants (Meagher, 2000) applying scientific strategies and technologies from a rapidly developing field called phytoremediation. The phytoremediation of toxic elemental and organic pollutants requires the use relatively different approaches (Meagher, 2000). Our current specific objectives are to use transgenic plants to control the chemical species, electrochemical state, and aboveground binding of mercury to (a) prevent methylmercury from entering the food-chain, (b) remove mercury from polluted sites, and (c) hyperaccumulate mercury in aboveground tissues for later harvest. Various parts of this strategy are being critically tested by examining different genes in model plants and field species and comparing the results to control plants as recently reviewed (Meagher et al., 2000; Rugh et al., 2000).

  15. The engineered phytoremediation of ionic and methylmercury pollution 70054yr.2000.doc

    SciTech Connect

    Meagher, Richard B.

    2000-06-01

    Our long-term objective is to enable highly productive plant species to extract, resist, detoxify, and/or sequester toxic heavy metal pollutants (Meagher, 2000). We have focused our research on the phytoremediation of soil and water-borne ionic and organic mercury (Meagher and Rugh, 1996; Meagher et al., 2000). Mercury pollution is a serious world-wide problem affecting the health of human and wild-life populations. The Department of Energy's Oak Ridge National Laboratory and Brookhaven National Laboratory have sites with significant levels of mercury contamination that could be cleaned by applying the scientific discoveries and new phytoremediation technologies described in this proposal. In the near future, the experience gained through engineering plants that hyperaccumulate mercury, can be applied to extraction or accumulation of various toxic heavy metal and radionuclide contaminates at dozens of DOE sites.

  16. Differential expression of proteins induced by lead in the Dwarf Sunflower Helianthus annuus.

    PubMed

    Walliwalagedara, Chamari; Atkinson, Ian; van Keulen, Harry; Cutright, Teresa; Wei, Robert

    2010-09-01

    The Dwarf Sunflower (Helianthus annuus) is a hyperaccumulator of toxic metals including cadmium (Cd), mercury (Hg), nickel (Ni), and lead (Pb). In order to identify stress response to Pb, plants were exposed to a mixture of 30 mg/l of three ions, Cd, Cr, and Ni, with and without Pb. Soluble proteins were resolved by two-dimensional gel electrophoresis. Four proteins were differentially expressed and very abundant in the leaf samples after plants were exposed to all these four metals. The first protein spot contained two proteins: chitinase and a chloroplast drought-induced stress protein CDSP-34. The second spot contained a thaumatin-like protein. Two proteins in spot 3 were identified as heat-shock cognate 70-1 and the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Several peptides were identified in spot 4 but none could be matched to any sequence in the NCBI database.

  17. Development and reproductive potential of diamondback moth (Lepidoptera: Plutellidae) on selected wild crucifer species.

    PubMed

    Niu, Yan-Qin; Sun, Yuan-Xing; Liu, Tong-Xian

    2014-02-01

    The diamondback moth, Plutella xylostella (L.), is an oligophagous insect that primarily feeds on members of the family Cruciferae. The development, survival, and reproductive potential of P. xylostella were studied on eight wild cruciferous species: Rorippa indica (L.) Hiern, Cardamine hirsuta L., Descurainia sophia (L.) Webb ex Prantl, Capsella bursa-pastoris (L.) Medic, Cardamine leucantha (Tausch) O. E. Schulz, Orychophragmus violaceus (L.) O. E. Schulz, Thlaspi arvense L., and Cardamine macrophylla Willd. Developmental durations of immatures from egg to adult emergence differed significantly among the plant species, with the longest period recorded on C. macrophylla (20.8 d) and the shortest on R. indica (15.8 d). The female pupae of P. xylostella reared on C. leucantha and T. arvense were lighter (4.2 and 4.3 mg/pupa) than those reared on other hosts (5.2-6.5 mg/pupa), and the male pupae from T. arvense were the lightest (3.1 mg/pupa) among all colonies. Survival from egg to adult emergence ranged from 95.7% on R. indica to 48.8% on T. arvense. The longevity (10.1 d) of P. xylostella female and the oviposition period (7.7 d) were the longest when larvae fed R. indica than those that fed on other wild hosts. Female adults of P. xylostella from O. violaceus, C. macrophylla, and Ca. bursa-pastoris had higher fecundity (305-351 eggs/female) than from other wild host plants, whereas that from R. indica had the lowest fecundity (134 eggs/female). C. hirsuta was the best wild host plant for P. xylostella because of the highest intrinsic rates of increase (rm = 0.2402), whereas T. arvense was the least favorable hosts with the lowest intrinsic rates of increase (rm = 0.1577). The results from this study will be useful for interpretation of the performance and population dynamics of P. xylostella on wild hosts and cultivated cruciferous vegetables.

  18. Arbuscular mycorrhiza and heavy metal tolerance.

    PubMed

    Hildebrandt, Ulrich; Regvar, Marjana; Bothe, Hermann

    2007-01-01

    Arbuscular mycorrhizal fungi (AMF) have repeatedly been demonstrated to alleviate heavy metal stress of plants. The current manuscript summarizes results obtained to date on the colonization of plants by AMF in heavy metal soils, the depositions of heavy metals in plant and fungal structures and the potential to use AMF-plant combinations in phytoremediation, with emphasis on pennycresses (Thlaspi ssp.). The focus of this manuscript is to describe and discuss studies on the expression of genes in plants and fungi under heavy metal stress. The summary is followed by data on differential gene expression in extraradical mycelia (ERM) of in vitro cultured Glomus intraradices Sy167 supplemented with different heavy metals (Cd, Cu or Zn). The expression of several genes encoding proteins potentially involved in heavy metal tolerance varied in their response to different heavy metals. Such proteins included a Zn transporter, a metallothionein, a 90 kD heat shock protein and a glutathione S-transferase (all assignments of protein function are putative). Studies on the expression of the selected genes were also performed with roots of Medicago truncatula grown in either a natural, Zn-rich heavy metal "Breinigerberg" soil or in a non-polluted soil supplemented with 100 microM ZnSO(4). The transcript levels of the genes analyzed were enhanced up to eight fold in roots grown in the heavy metal-containing soils. The data obtained demonstrate the heavy metal-dependent expression of different AMF genes in the intra- and extraradical mycelium. The distinct induction of genes coding for proteins possibly involved in the alleviation of damage caused by reactive oxygen species (a 90 kD heat shock protein and a glutathione S-transferase) might indicate that heavy metal-derived oxidative stress is the primary concern of the fungal partner in the symbiosis.

  19. Functional Characterization of a Gene in Sedum alfredii Hance Resembling Rubber Elongation Factor Endowed with Functions Associated with Cadmium Tolerance

    PubMed Central

    Liu, Mingying; Qiu, Wenming; He, Xuelian; Zheng, Liu; Song, Xixi; Han, Xiaojiao; Jiang, Jing; Qiao, Guirong; Sang, Jian; Liu, Mingqing; Zhuo, Renying

    2016-01-01

    Cadmium is a major toxic heavy-metal pollutant considering their bioaccumulation potential and persistence in the environment. The hyperaccumulating ecotype of Sedum alfredii Hance is a Zn/Cd co-hyperaccumulator inhabiting in a region of China with soils rich in Pb/Zn. Investigations into the underlying molecular regulatory mechanisms of Cd tolerance are of substantial interest. Here, library screening for genes related to cadmium tolerance identified a gene resembling the rubber elongation factor gene designated as SaREFl. The heterologous expression of SaREFl rescued the growth of a transformed Cd-sensitive strain (ycf1). Furthermore, SaREFl-expressing Arabidopsis plants were more tolerant to cadmium stress compared with wild type by measuring parameters of root length, fresh weight and physiological indexes. When under four different heavy metal treatments, we found that SaREFl responded most strongly to Cd and the root was the plant organ most sensitive to this heavy metal. Yeast two-hybrid screening of SaREFl as a bait led to the identification of five possible interacting targets in Sedum alfredii Hance. Among them, a gene annotated as prenylated Rab acceptor 1 (PRA1) domain protein was detected with a high frequency. Moreover, subcellular localization of SaREF1-GFP fusion protein revealed some patchy spots in cytosol suggesting potential association with organelles for its cellular functions. Our findings would further enrich the connotation of REF-like genes and provide theoretical assistance for the application in breeding heavy metal-tolerant plants. PMID:27446189

  20. Host plant growth promotion and cadmium detoxification in Solanum nigrum, mediated by endophytic fungi.

    PubMed

    Khan, Abdur Rahim; Ullah, Ihsan; Waqas, Muhammad; Park, Gun-Seok; Khan, Abdul Latif; Hong, Sung-Jun; Ullah, Rehman; Jung, Byung Kwon; Park, Chang Eon; Ur-Rehman, Shafiq; Lee, In-Jung; Shin, Jae-Ho

    2017-02-01

    Current investigation conducted to evaluate the associated fungal endophyte interactions of a Cd hyper-accumulator Solanum nigrum Korean ecotype under varying concentrations of Cd. Two indole-3-acetic acid (IAA) producing fungal strains, RSF-4L and RSF-6L, isolated from the leaves of S. nigrum, were initially screened for Cd tolerance and accumulation potential. In terms of dry biomass production, the strain RSF-6L showed higher tolerance and accumulation capacity for Cd toxicity in comparison to RSF-4L. Therefore, RSF-6L was applied in vivo to S. nigrum and grown for six weeks under Cd concentrations of 0, 10, and 30mgKg(-1) of dry sand. The effect of fungal inoculation assessed by plant physiological responses, endogenous biochemical regulations, and Cd profile in different tissues. Significant increase were observed in plant growth attributes such as shoot length, root length, dry biomass, leaf area, and chlorophyll contents in inoculated RSF-6L plants in comparison to non-inoculated plants with or without Cd contamination. RSF-6L inoculation decreased uptake of Cd in roots and above ground parts, as evidenced by a low bio-concentration factor (BCF) and improved tolerance index (TI). However, Cd concentration in the leaves remained the same for inoculated and non-inoculated plants under Cd spiking. Fungal inoculation protected the host plants, as evidenced by low peroxidase (POD) and polyphenol peroxidase (PPO) activities and high catalase (CAT) activity. Application of appropriate fungal inoculation that can improve tolerance mechanisms of hyper-accumulators and reduce Cd uptake can be recommended for phyto-stabilisation/immobilisation of heavy metals in crop fields.

  1. A phytogeochemical study of the Trás-os-Montes region (NE Portugal): possible species for plant-based soil remediation technologies.

    PubMed

    Díez Lázaro, J; Kidd, P S; Monterroso Martínez, C

    2006-02-01

    Phytoremediation techniques are now considered to be promising alternatives to conventional techniques for the remediation of diffused or moderately contaminated soils. Despite their growing acceptance relatively few plant species have been studied for phytoremediation purposes. Further geobotanical surveys and plant screenings are necessary since these could lead to the identification of additional species with potential value for such applications. Serpentine areas could prove valuable sources of such plants. In this study heavy metal accumulation was determined in the flora associated with ultramafic and non-ultramafic soils of the Trás-os-Montes region of NE Portugal. Study sites were selected to represent a wide range of soil-forming rocks (serpentinized (S), ultrabasic (UB), basic (B) and acid (migmatite, M and schists, SC) rocks) and plant metal accumulation was related to soil metal bioavailability. Nine plant species (representing 7 families) were sampled including the Ni hyperaccumulator Alyssum serpyllifolium subsp. lusitanicum. The greatest metal accumulation, transport (leaf[metal]:root[metal]) and bioaccumulation (leaf[metal]/soil[metal]) was found in four of the non metal-hyperaccumulating species: Cistus ladanifer, Lavandula stoechas, Plantago subulata subsp. radicata and Thymus mastichina. Metal accumulation depended on both the plant species and the edaphic conditions at its provenance. While P. subulata is of less interest due to its low biomass the remaining three species could be of use in phytoremediation technologies such as phytoextraction, and particularly in soils contaminated with Cr, Mn and Zn. These three species are also of economic interest due to their oil and fragrance producing biomass.

  2. Evaluation of three endemic Mediterranean plant species Atriplex halimus, Medicago lupulina and Portulaca oleracea for Phytoremediation of Ni, Pb and Zn

    NASA Astrophysics Data System (ADS)

    Chami, Ziad Al; Amer, Nasser; Bitar, Lina Al; Mondelli, Donato; Dumontet, Stefano

    2013-04-01

    The success of phytoremediation depends upon the identification of suitable plants species that hyperaccumulate/tolerate heavy metals and produce large amounts of biomass. In this study, three endemic Mediterranean plant species Atriplex halimus, Medicago lupulina and Portulaca oleracea, were grown hydroponically to assess their potential use in phytoremediation of Ni, Pb and Zn and biomass production. The objective of this research is to improve phytoremediation procedures by searching for a new endemic Mediterranean plant species which can be used for phytoremediation of low/moderate contamination in the Mediterranean arid and semiarid conditions and bioenergy production. The hydroponics experiment was carried out in a growth chamber using half strength Hoagland's solution as control (CTR) and 5 concentrations for Pb and Zn (5, 10, 25, 50 and 100 mg L-1) and 3 concentrations for Ni (1, 2, and 5 mg L-1). Complete randomized design with five replications was adopted. Main growth parameters (shoot and root dry weight, shoot and root length and chlorophyll content) were determined. Shoots and roots were analyzed for their metals contents. Some interesting contributions of this research are: (i) plant metal uptake efficiency ranked as follows: A. halimus > M. lupulina > P. oleracea, whereas heavy metal toxicity ranked as follows: Ni > Zn > Pb, (ii) none of the plant species was identified as hyperaccumulator, (iii) Atriplex halimus and Medicago lupulina can accumulate Ni, Pb and Zn in their roots, (iv) translocate small fraction to their above ground biomass, and (v) indicate moderate pollution levels of the environment. In addition, as they are a good biomass producer, they can be used in phytostabilisation of marginal lands and their above ground biomass can be used for livestock feeding as well for bioenergy production.

  3. The effect of EDDS and citrate on the uptake of lead in hydroponically grown Matthiola flavida.

    PubMed

    Mohtadi, Ahmad; Ghaderian, Seyed Majid; Schat, Henk

    2013-10-01

    Root and shoot lead concentrations and the impact of chelating agents on these were investigated in two populations of the novel metallophyte Matthiola flavida. Plants were exposed in hydroponics to Pb(NO3)2, supplied alone, or in combination with citric acid, or EDDS. When supplied at concentrations expected to bind about 95% of the Pb in a solution containing 1-μM Pb (1000 μM citrate or 3.1 μM EDDS, respectively), the root and shoot Pb concentrations were dramatically lowered, in comparison with a 1-μM free ionic Pb control exposure. A 1-mM EDDS+1-μM Pb treatment decreased the plants' Pb concentrations further, even to undetectable levels in one population. At 100 μM Pb in a 1-mM EDDS-amended solution the Pb concentration increased strongly in shoots, but barely in roots, in comparison with the 1-μM Pb+1-mM EDDS treatment, without causing toxicity symptoms. Further increments of the Pb concentration in the 1-mM EDDS-amended solution, i.e. to 800 and 990 μM, caused Pb hyperaccumulation, both in roots and in shoots, associated with a complete arrest of root growth and foliar necrosis. M. flavida seemed to be devoid of constitutive mechanisms for uptake of Pb-citrate or Pb-EDDS complexes. Hyperaccumulation of Pb-EDDS occurred only at high exposure levels. Pb-EDDS was toxic, but is much less so than free Pb. Free EDDS did not seem to be toxic at the concentrations tested.

  4. Orchestration of three transporters and distinct vascular structures in node for intervascular transfer of silicon in rice

    PubMed Central

    Yamaji, Naoki; Sakurai, Gen; Mitani-Ueno, Namiki; Ma, Jian Feng

    2015-01-01

    Requirement of mineral elements in different plant tissues is not often consistent with their transpiration rate; therefore, plants have developed systems for preferential distribution of mineral elements to the developing tissues with low transpiration. Here we took silicon (Si) as an example and revealed an efficient system for preferential distribution of Si in the node of rice (Oryza sativa). Rice is able to accumulate more than 10% Si of the dry weight in the husk, which is required for protecting the grains from water loss and pathogen infection. However, it has been unknown for a long time how this hyperaccumulation is achieved. We found that three transporters (Lsi2, Lsi3, and Lsi6) located at the node are involved in the intervascular transfer, which is required for the preferential distribution of Si. Lsi2 was polarly localized to the bundle sheath cell layer around the enlarged vascular bundles, which is next to the xylem transfer cell layer where Lsi6 is localized. Lsi3 was located in the parenchyma tissues between enlarged vascular bundles and diffuse vascular bundles. Similar to Lsi6, knockout of Lsi2 and Lsi3 also resulted in decreased distribution of Si to the panicles but increased Si to the flag leaf. Furthermore, we constructed a mathematical model for Si distribution and revealed that in addition to cooperation of three transporters, an apoplastic barrier localized at the bundle sheath cells and development of the enlarged vascular bundles in node are also required for the hyperaccumulation of Si in rice husk. PMID:26283388

  5. Bioaugmentation with Endophytic Bacterium E6S Homologous to Achromobacter piechaudii Enhances Metal Rhizoaccumulation in Host Sedum plumbizincicola

    PubMed Central

    Ma, Ying; Zhang, Chang; Oliveira, Rui S.; Freitas, Helena; Luo, Yongming

    2016-01-01

    Application of hyperaccumulator-endophyte symbiotic systems is a potential approach to improve phytoremediation efficiency, since some beneficial endophytic bacteria are able to detoxify heavy metals, alter metal solubility in soil, and facilitate plant growth. The objective of this study was to isolate multi-metal resistant and plant beneficial endophytic bacteria and to evaluate their role in enhancing plant growth and metal accumulation/translocation. The metal resistant endophytic bacterial strain E6S was isolated from stems of the Zn/Cd hyperaccumulator plant Sedum plumbizincicola growing in metalliferous mine soils using Dworkin and Foster salts minimal agar medium with 1-aminocyclopropane-1-carboxylate (ACC) as the sole nitrogen source, and identified as homologous to Achromobacter piechaudii based on morphological and biochemical characteristics, partial 16S rDNA sequence and phylogenetic analysis. Strain E6S showed high level of resistance to various metals (Cd, Zn, and Pb). Besides utilizing ACC, strain E6S exhibited plant beneficial traits, such as solubilization of phosphate and production of indole-3-acetic acid. Inoculation with E6S significantly increased the bioavailability of Cd, Zn, and Pb in soil. In addition, bacterial cells bound considerable amounts of metal ions in the following order: Zn > Cd >Pb. Inoculation of E6S significantly stimulated plant biomass, uptake and bioaccumulation of Cd, Zn, and Pb. However, E6S greatly reduced the root to shoot translocation of Cd and Zn, indicating that bacterial inoculation assisted the host plant to uptake and store heavy metals in its root system. Inoculation with the endophytic bacterium E6S homologous to A. piechaudii can improve phytostabilization of metalliferous soils due to its effective ability to enhance in situ metal rhizoaccumulation in plants. PMID:26870079

  6. The extent of arsenic and of metal uptake by aboveground tissues of Pteris vittata and Cyperus involucratus growing in copper- and cobalt-rich tailings of the Zambian copperbelt.

    PubMed

    Kříbek, Bohdan; Mihaljevič, Martin; Sracek, Ondra; Knésl, Ilja; Ettler, Vojtěch; Nyambe, Imasiku

    2011-08-01

    The extent of arsenic (As) and metal accumulation in fronds of the As hyperaccumulator Pteris vittata (Chinese brake fern) and in leaves of Cyperus involucratus, which grow on the surface of an old flotation tailings pond in the Zambian Copperbelt province, was studied. The tailings consist of two types of material with distinct chemical composition: (1) reddish-brown tailings rich in As, iron (Fe), and other metals, and (2) grey-green tailings with a lower content of As, Fe, and other metals, apart from manganese (Mn). P. vittata accumulates from 2350 to 5018 μg g(-1) As (total dry weight [dw]) in its fronds regardless of different total and plant-available As concentrations in both types of tailings. Concentrations of As in C. involucratus leaves are much lower (0.24-30.3 μg g(-1) dw). Contents of copper (Cu) and cobalt (Co) in fronds of P. vittata (151-237 and 18-38 μg g(-1) dw, respectively) and in leaves of C. involucratus (96-151 and 9-14 μg g(-1) dw, respectively) are high, whereas concentrations of other metals (Fe, Mn, and zinc [Zn]) are low and comparable with contents of the given metals in common plants. Despite great differences in metal concentrations in the two types of deposited materials, concentrations of most metals in plant tissues are very similar. This indicates an exclusion or avoidance mechanism operating when concentrations of the metals in substrate are particularly high. The results of the investigation show that Chinese brake fern is not only a hyperaccumulator of As but has adapted itself to high concentrations of Cu and Co in flotation tailings of the Zambian Copperbelt.

  7. Testing the joint effects hypothesis of elemental defense using Spodoptera exigua.

    PubMed

    Cheruiyot, Dorothy J; Boyd, Robert S; Moar, William

    2015-02-01

    Metal hyperaccumulation may be an elemental defense, in which high concentrations of a metal in plant tissues decrease herbivore survival or growth rate. The Joint Effects Hypothesis suggests that a combination of metals, or a combination of a metal with an organic compound, may have an enhanced defensive effect. The enhancement may be additive or synergistic: in either case the concentration of a particular metal necessary to provide a defensive benefit for the plant is lowered. We tested the Joint Effects Hypothesis using Spodoptera exigua (beet armyworm) neonates fed artificial diets. Metal + metal experiments utilized diets amended with metal pairs, using four metals commonly hyperaccumulated by plants (Co, Cu, Ni, and Zn). We also conducted metal + organic compound experiments, pairing each metal with nicotine, mustard seed powder, or tannic acid. We tested for joint effects using both lethal (LC20 levels) and sublethal concentrations (10-25 % reduced larval weight) of the chemicals tested. For all experiments, either additive or synergistic effects were found. Of the metal + metal pairs tested, three (Co + Cu, Cu + Zn, and Ni + Zn) were synergistic in lethal concentration tests and only Co + Cu was synergistic in sublethal tests. For metal + organic combination lethal tests, synergism occurred for all combinations except for Co or Ni + nicotine, Ni + mustard seed powder, and Zn + nicotine. For sublethal tests, Zn + all three organic chemicals, Co + mustard seed powder or tannic acid, and Cu + nicotine, were synergistic. These results support the Joint Effects Hypothesis, suggesting that metals combined with other metals or organic compounds may be more effective against herbivores than individual metals.

  8. Literature review: Phytoaccumulation of chromium, uranium, and plutonium in plant systems

    SciTech Connect

    Hossner, L.R.; Loeppert, R.H.; Newton, R.J.; Szaniszlo, P.J.

    1998-05-01

    Phytoremediation is an integrated multidisciplinary approach to the cleanup of contaminated soils, which combines the disciplines of plant physiology, soil chemistry, and soil microbiology. Metal hyperaccumulator plants are attracting increasing attention because of their potential application in decontamination of metal-polluted soils. Traditional engineering technologies may be too expensive for the remediation of most sites. Removal of metals from these soils using accumulator plants is the goal of phytoremediation. The emphasis of this review has been placed on chromium (Cr), plutonium (Pu), and uranium (U). With the exception of Cr, these metals and their decay products exhibit two problems, specifically, radiation dose hazards and their chemical toxicity. The radiation hazard introduces the need for special precautions in reclamation beyond that associated with non-radioactive metals. The uptake of beneficial metals by plants occurs predominantly by way of channels, pores, and transporters in the root plasma membrane. Plants characteristically exhibit a remarkable capacity to absorb what they need and exclude what they don`t need. But most vascular plants absorb toxic and heavy metals through their roots to some extent, though to varying degrees, from negligible to substantial. Sometimes absorption occurs because of the chemical similarity between beneficial and toxic metals. Some plants utilize exclusion mechanisms, where there is a reduced uptake by the roots or a restricted transport of the metal from root to shoot. At the other extreme, hyperaccumulator plants absorb and concentrate metals in both roots and shoots. Some plant species endemic to metalliferous soils accumulate metals in percent concentrations in the leaf dry matter.

  9. Enhancement of cadmium tolerance and accumulation by introducing Perilla frutescens (L.) Britt var. frutescens genes in Nicotiana tabacum L. plants.

    PubMed

    Wei, Keqiang; Pang, Shengxi; Yang, Junxian; Wei, Zhizhong

    2015-04-01

    The tobacco has the genetic potential to remove toxic metals from the soil. To develop hyperaccumulating tobacco plants, distant hybridization between tobacco (Nicotiana tabacum L.), a high-biomass crop, and Perilla frutescens (L.) Britt var. frutescens, a newfound Cd-hyperaccumulator species, was carried out using a novel method viz. pollination following grafting. Their hybrid nature was preliminarily confirmed by phenotype, isozyme pattern, random amplified polymorphic DNA (RAPD) and metabolites analysis. About 120 putative F2 hybrids derived from the cross-combination [(N. sylvestris Speg. & Comes rootstock + N. tabacum L. var. 78-04 scion) × P. frutescens (L.) Britt var. frutescens] were then subjected to up to 300 μM CdCl2 in hydroponic conditions for 10 days. Results showed five seedlings were more resistant to Cd than female parent and accumulated 314.6 ± 99.9 mg kg(-1) Cd in their aerial biomass, which was 5.7 times greater than that in "78-04" tobacco (47.2 ± 3.56 mg kg(-1)) (P ≤ 0.05). Two of these seedlings exceeded male parent P. frutescens in the Cd concentration of shoots and reached 424 and 396 mg kg(-1), which was 13% and 6% greater for that of perilla (374.2 ± 10.38 mg kg(-1)), respectively. Compared with parents, two other F2 hybrids tended to accumulate more Cd in the root with bioconcentration factor (BCF) 7.05 and 5.17, respectively. Only one hybrid showed lower Cd concentration but transferred Cd more effectively from the root to the shoot than parents and other F2 hybrids, with the maximum translocation factor (TF) value 1.37. These indicated that the introduction of P. frutescens genes could obviously enhance the cadmium tolerance and accumulation of superior individuals.

  10. Removal of copper from aqueous solutions by rhizofiltration using genetically modified hairy roots expressing a bacterial Cu-binding protein.

    PubMed

    Pérez-Palacios, Patricia; Agostini, Elizabeth; Ibáñez, Sabrina G; Talano, Melina A; Rodríguez-Llorente, Ignacio D; Caviedes, Miguel A; Pajuelo, Eloísa

    2017-01-31

    The aim of this work was to develop a biotechnological tool to hyperaccumulate high copper (Cu) concentrations from wastewaters. Transgenic tobacco hairy roots were obtained by expressing, either the wild-type version of the gene copC from Pseudomonas fluorescens in the cytoplasm of plant cells (CuHR), or a modified version targeted to the vacuole (CuHR-V). Control hairy roots transformed with the empty vector (HR) were also generated. The roots were incubated in the presence of solutions containing Cu (from 1 to 50 mM). At 5 mM external copper, transgenic hairy roots accumulated twice the amount of copper accumulated by control hairy roots. However, at 50 mM Cu, accumulation in both transgenic and control roots reached similar values. Maximum Cu accumulation achieved by transgenic hairy roots was 45,000 µg g(-1) at 50 mM external Cu. Despite the high Cu accumulation, transgenic hairy roots, particularly CuHR-V, showed less toxicity symptoms, in correlation with lower activity of several antioxidant enzymes and lower malondialdehyde (MDA) levels. Moreover, CuHR-V roots displayed low values of the oxidative stress index (OSI) - a global parameter proposed for oxidative stress - indicating that targeting CopC to the vacuole could alleviate the oxidative stress caused by Cu. Our results suggest that expressing copC in transgenic hairy roots is a suitable strategy to obtain Cu-hyperaccumulator hairy roots with less toxicity stress symptoms.

  11. Phytoremediation potential of some halophytic species for soil salinity.

    PubMed

    Devi, S; Nandwal, A S; Angrish, R; Arya, S S; Kumar, N; Sharma, S K

    2016-01-01

    Phytoremediation potential of six halophytic species i.e. Suaeda nudiflora, Suaeda fruticosa, Portulaca oleracea, Atriplex lentiformis, Parkinsonia aculeata and Xanthium strumarium was assessed under screen house conditions. Plants were raised at 8.0, 12.0, 16.0, and 20.0 dSm(-1) of chloride-dominated salinity. The control plants were irrigated with canal water. Sampling was done at vegetative stage (60-75 DAS). About 95 percent seed germination occurred up to 12 dSm(-1) and thereafter declined slightly. Mean plant height and dry weight plant(-1) were significantly decreased from 48.71 to 32.44 cm and from 1.73 to 0.61g plant(-1) respectively upon salinization. Na(+)/K(+) ratio (0.87 to 2.72), Na(+)/ Ca(2+) + Mg(2+) (0.48 to 1.54) and Cl(-)/SO4(2-) (0.94 to 5.04) ratio showed increasing trend. Salinity susceptibility index was found minimum in Suaeda fruticosa (0.72) and maximum in Parkinsonia aculeata (1.17). Total ionic content also declined and magnitude of decline varied from 8.51 to 18.91% at 8 dSm(-1) and 1.85 to 7.12% at 20 dSm(-1) of salinity. On the basis of phytoremediation potential Suaeda fruticosa (1170.02 mg plant(-1)), Atriplex lentiformis (777.87 mg plant(-1)) were the best salt hyperaccumulator plants whereas Xanthium strumarium (349.61 mg plant(-1)) and Parkinsonia aculeata (310.59 mg plant(-1)) were the least hyperaccumulator plants.

  12. Element accumulation patterns of deciduous and evergreen tree seedlings on acid soils: implications for sensitivity to manganese toxicity.

    PubMed

    St Clair, Samuel B; Lynch, Jonathan P

    2005-01-01

    Foliar nutrient imbalances, including the hyperaccumulation of manganese (Mn), are correlated with symptoms of declining health in sensitive tree species growing on acidic forest soils. The objectives of this study were to: (1) compare foliar nutrient accumulation patterns of six deciduous (sugar maple (Acer saccharum Marsh.), red maple (Acer rubrum L.), red oak (Quercus rubra L.), white oak (Quercus alba L.), black cherry (Prunus serotina Ehrh.) and white ash (Fraxinus americana L.)) and three evergreen (eastern hemlock (Tsuga canadensis L.), white pine (Pinus strobus L.) and white spruce (Picea glauca (Moench) Voss.)) tree species growing on acidic forest soils; and (2) examine how leaf phenology and other traits that distinguish evergreen and deciduous tree species influence foliar Mn accumulation rates and sensitivity to excess Mn. For the first objective, leaf samples of seedlings from five acidic, non-glaciated field sites on Pennsylvania's Allegheny Plateau were collected and analyzed for leaf element concentrations. In a second study, we examined growth and photosynthetic responses of seedlings exposed to excess Mn in sand culture. In field samples, Mn in deciduous foliage hyperaccumulated to concentrations more than twice as high as those found in evergreen needles. Among species, sugar maple was the most sensitive to excess Mn based on growth and photosynthetic measurements. Photosynthesis in red maple and red oak was also sensitive to excess Mn, whereas white oak, black cherry, white ash and the three evergreen species were tolerant of excess Mn. Among the nine species, relative rates of photosynthesis were negatively correlated with foliar Mn concentrations, suggesting that photosynthetic sensitivity to Mn is a function of its rate of accumulation in seedling foliage.

  13. Phytoremediation of Ionic and Methyl Mercury Pollution

    SciTech Connect

    Meagher, Richard B.

    2004-12-01

    Phytoremediation is defined as the use of plants to extract, resist, detoxify, and/or sequester toxic environmental pollutants. The long-term goal of the proposed research is to develop and test highly productive, field-adapted plant species that have been engineered for the phytoremediation of mercury. A variety of different genes, which should enable plants to clean mercury polluted sites are being tested as tools for mercury phytoremediation, first in model laboratory plants and then in potential field species. Several of these genes have already been shown to enhance mercury phytoremediation. Mercury pollution is a serious, world-wide problem affecting the health of human and wildlife populations. Environmentally, the most serious mercury threat is the production of methylmercury (CH3Hg+) by native bacteria at mercury contaminated wetland sites. Methylmercury is inherently more toxic than metallic (Hg(0)) or ionic (Hg(II)) mercury, and because methylmercury is prolifically biomagnified up the food chain, it poses the most immediate danger to animal populations. We have successfully engineered two model plants, Arabidopsis and tobacco, to use the bacterial merB gene to convert methylmercury to less toxic ionic mercury and to use the bacterial merA gene to further detoxify ionic mercury to the least toxic form of mercury, metallic mercury. Plants expressing both MerA and MerB proteins detoxify methylmercury in two steps to the metallic form. These plants germinate, grow, and set seed at normal growth rates on levels of methylmercury or ionic mercury that are lethal to normal plants. Our newest efforts involve engineering plants with several additional bacterial and plant genes that allow for higher levels of mercury resistance and mercury hyperaccumulation. The potential for these plants to hyperaccumulate mercury was further advanced by developing constitutive, aboveground, and root-specific gene expression systems.

  14. Dissolution of different zinc salts and zn uptake by Sedum alfredii and maize in mono- and co-cropping under hydroponic culture.

    PubMed

    Jiang, Cheng'ai; Wu, Qitang; Zeng, Shucai; Chen, Xian; Wei, Zebin; Long, Xinxian

    2013-09-01

    Previous soil pot and field experiments demonstrated that co-cropping the hyperaccumulator Sedum alfredii with maize increased Zn phytoextraction by S. alfredii and decreased Zn uptake by maize shoots. This hydroponic experiment was conducted to investigate whether the facilitation of Zn phytoextraction by S. alfredii resulted from improved dissolution in this co-cropping system and its relation to root exudates. S. alfredii and maize were mono- and co-cropped (without a root barrier) in nutrient solution spiked with four Zn compounds, ZnS, ZnO, Zn3(PO4)2 and 5ZnO x 2CO3-4H2O (represented as ZnCO3) at 1000 mg/L Zn for 15 days without renewal of nutrient solution after pre-culture. The root exudates were collected under incomplete sterilization and analyzed. The results indicated that the difference in Zn salts had a greater influence on the Zn concentration in maize than for S. alfredii, varying from 210-2603 mg/kg for maize shoots and 6445-12476 mg/kg for S. alfredii in the same order: ZnCO3 > ZnO > Zn3(PO4)2 > ZnS. For the four kinds of Zn sources in this experiment, co-cropping with maize did not improve Zn phytoextraction by S. alfredii. In most cases, compared to co-cropped and mono-cropped maize, mono-cropped S. alfredii resulted in the highest Zn2+ concentration in the remaining nutrient solution, and also had a higher total concentration of low molecular weight organic acids (LMWOA) and lower pH of root exudation. Root exudates did partly influence Zn hyperaccumulation in S. alfredii.

  15. Bacterially Induced Weathering of Ultramafic Rock and Its Implications for Phytoextraction

    PubMed Central

    Kidd, Petra; Kuffner, Melanie; Prieto-Fernández, Ángeles; Hann, Stephan; Monterroso, Carmela; Sessitsch, Angela; Wenzel, Walter; Puschenreiter, Markus

    2013-01-01

    The bioavailability of metals in soil is often cited as a limiting factor of phytoextraction (or phytomining). Bacterial metabolites, such as organic acids, siderophores, or biosurfactants, have been shown to mobilize metals, and their use to improve metal extraction has been proposed. In this study, the weathering capacities of, and Ni mobilization by, bacterial strains were evaluated. Minimal medium containing ground ultramafic rock was inoculated with either of two Arthrobacter strains: LA44 (indole acetic acid [IAA] producer) or SBA82 (siderophore producer, PO4 solubilizer, and IAA producer). Trace elements and organic compounds were determined in aliquots taken at different time intervals after inoculation. Trace metal fractionation was carried out on the remaining rock at the end of the experiment. The results suggest that the strains act upon different mineral phases. LA44 is a more efficient Ni mobilizer, apparently solubilizing Ni associated with Mn oxides, and this appeared to be related to oxalate production. SBA82 also leads to release of Ni and Mn, albeit to a much lower extent. In this case, the concurrent mobilization of Fe and Si indicates preferential weathering of Fe oxides and serpentine minerals, possibly related to the siderophore production capacity of the strain. The same bacterial strains were tested in a soil-plant system: the Ni hyperaccumulator Alyssum serpyllifolium subsp. malacitanum was grown in ultramafic soil in a rhizobox system and inoculated with each bacterial strain. At harvest, biomass production and shoot Ni concentrations were higher in plants from inoculated pots than from noninoculated pots. Ni yield was significantly enhanced in plants inoculated with LA44. These results suggest that Ni-mobilizing inoculants could be useful for improving Ni uptake by hyperaccumulator plants. PMID:23793627

  16. Nickel and manganese transfer from soil to plant in lateritic mining soils from New Caledonia

    NASA Astrophysics Data System (ADS)

    Pouschat, P.; Rose, J.; Alliot, I.; Dominici, C.; Keller, C.; Laffont-Schwob, I.; Olivi, L.; Ambrosi, J.-P.

    2009-04-01

    New Caledonian ferritic soils (more than 50 % of iron) are naturally rich in metals (chromium, nickel, cobalt, and manganese), deficient in major nutrients (nitrogen, phosphorous, and potassium), and unbalanced for the calcium/magnesium ratio. Under these particular ecological conditions, New Caledonia, recognized as a hot-spot of biodiversity, is a natural laboratory to study and understand the adaptation strategies of plants to metalliferous soils, and particularly the tolerance and (hyper)accumulation of metals by plants. Moreover, understanding such mechanisms is essential to develop rehabilitation or phytoremediation techniques for polluted soils, as well as phytomining techniques. Thus, in order to understand the soil - plant relationship and metal mobility along a toposequence in a future nickel mining massif, field experiments were conducted in an isolated ultramafic massif of New Caledonia. Several plant species of two endemic and frequent plant genera were chosen: Tristaniopsis guillainii and T. calobuxus (Myrtaceae), and Phyllanthus serpentinus and P. favieri (Euphorbiaceae), because of their nickel and/or manganese accumulating or hyperaccumulating nature. Leaves, twigs, and roots of all plants were collected along the soil sequence and their associated rhizospheric and bulk soils were sampled. Next, a series of characterization techniques were adapted and then coupled to cryogenics. The combined use of those multiple techniques (cryo-microtomy, cryo-SEM, µXRF, cryo-XAS, and soil characterization) allowed to study co-location and speciation of nickel and manganese in the different plant organs and soils (rhizospheric and bulk). Bioaccumulated nickel and manganese had different distribution patterns. In leaves, Ni accumulated in non photosynthetic tissues (e.g. epidermis) whereas Mn preferentially accumulated in mesophyll whatever the plant species. Nevertheless, in spite of a different speciation in soils, nickel and manganese were both found as

  17. Increased lead availability and enzyme activities in root-adhering soil of Lantana camara during phytoextraction in the presence of earthworms.

    PubMed

    Jusselme, My Dung; Miambi, Edouard; Mora, Philippe; Diouf, Michel; Rouland-Lefèvre, Corinne

    2013-02-15

    Earthworms are known to increase availability of heavy metals in soils and also play an important role in maintaining the structure and quality of soil. The introduction of earthworms into soils contaminated with metals in the presence of a potential hyperaccumulator has been suggested as an aid for phytoremediation processes. The present study was conducted to evaluate: (i) the effects of earthworms on lead availability in artificially contaminated soil at 500 and 1000 mg kg(-1) Pb in the presence of Lantana camara, a hyperaccumulator, (ii) the effects of earthworms and lead on soil properties such as pH, cation exchange capacity (CEC), organic matter (OM), total and available N, P and K and (iii) soil enzyme activities. Earthworms increased the bioavailable Pb in root-adhering soil by a factor of 2 to 3 in the contaminated soils at concentrations of 500 to 1000 mg Pb kg(-1), respectively. In lead contaminated soils, the presence of earthworms led to a significant decrease in soil pH by about 0.2 but increased CEC by 17% and OM by more than 30%. Earthworm activities also increased the activities of N-acetylglucosamidase, β-glucosidase, cellulase, xylanase, alkaline and acid phosphatase, urease and fluorescein diacetate assay (FDA). These results indicate that the ecological context for phytoremediation should be broadened by considering plant-soil-earthworm interactions as they influence both plant health and absorption of heavy metals. They also showed that the enzyme activities monitored could serve as useful proxies for phytoremediation capability and, more generally, for soil quality as a whole.

  18. Enhanced cadmium accumulation and tolerance in transgenic tobacco overexpressing rice metal tolerance protein gene OsMTP1 is promising for phytoremediation.

    PubMed

    Das, Natasha; Bhattacharya, Surajit; Maiti, Mrinal K

    2016-08-01

    One of the most grievous heavy metal pollutants in the environment is cadmium (Cd), which is not only responsible for the crop yield loss owing to its phytotoxicity, but also for the human health hazards as the toxic elements usually accumulate in the consumable parts of crop plants. In the present study, we aimed to isolate and functionally characterize the OsMTP1 gene from indica rice (Oryza sativa L. cv. IR64) to study its potential application for efficient phytoremediation of Cd. The 1257 bp coding DNA sequence (CDS) of OsMTP1 encodes a ∼46 kDa protein belonging to the cation diffusion facilitator (CDF) or metal tolerance/transport protein (MTP) family. The OsMTP1 transcript in rice plant was found to respond during external Cd stress. Heterologous expression of OsMTP1 in tobacco resulted in the reduction of Cd stress-induced phytotoxic effects, including growth inhibition, lipid peroxidation, and cell death. Compared to untransformed control, the transgenic tobacco plants showed enhanced vacuolar thiol content, indicating vacuolar localization of the sequestered Cd. The transgenic tobacco plants exhibited significantly higher biomass growth (2.2-2.8-folds) and hyperaccumulation of Cd (1.96-2.22-folds) compared to untransformed control under Cd exposure. The transgenic plants also showed moderate tolerance and accumulation of arsenic (As) upon exogenous As stress, signifying broad substrate specificity of OsMTP1. Together, findings of our research suggest that the transgenic tobacco plants overexpressing OsMTP1 with its hyperaccumulating activity and increased growth rate could be useful for future phytoremediation applications to clean up the Cd-contaminated soil.

  19. [Promotion effects of microorganisms on phytoremediation of heavy metals-contaminated soil].

    PubMed

    Yang, Zhuo; Wang, Zhan-Li; Li, Bo-Wen; Zhang, Rui-Fang

    2009-08-01

    Taking Brassica juncea as a hyperaccumulator, a pot experiment was conducted to study the effects of Bacillusme gaterium - Bacillus mucilaginosus mixed agent and Aspergillus niger 30177 fermentation liquor on the phytoremediation of Cd, Pb, and Zn-contaminated soil. The B. gaterium - B. mucilaginosus mixed agent not only promoted the growth of B. juncea, but also increased the soil Cd, Pb, and Zn uptake by the hyperaccumulator, with the phytoremediation efficiency enhanced greatly. The enrichment amount of Cd, Pb and Zn in B. juncea on the soil added with soluble Cd, Pb and Zn increased by 1.18, 1.54 and 0.85 folds, while that on the soil added with Cd, Pb and Zn-contaminated sediment increased by 4.00, 0. 64 and 0. 65 folds, respectively, compared with the control. A. niger 30177 fermentation liquor increased the soil Cd, Pb, and Zn uptake by B. juncea. Comparing with the control, the enrichment amount of Cd, Pb and Zn in aboveground part of B. juncea on the soil added with soluble Cd, Pb and Zn increased by 88.82%, 129.04% and 16.80%, while that on the soil added with Cd, Pb and Zn-contaminated sediment increased by 78.95%, 113.63% and 33.85%, respectively. However, A. niger 30177 fermentation liquor decreased the B. juncea biomass greatly, having less effect in the enhancement of phytoremediation efficiency. The analysis of reversed-phase high performance liquid chromatography showed that the fermentation liquor of B. gaterium and B. mucilaginosus contained some organic acids such as oxalic acid and citric acid. These acids could dissolve the heavy metals to some degree, and accordingly, enhance the bioavailability of the metals.

  20. Genome expression profile analysis reveals important transcripts in maize roots responding to the stress of heavy metal Pb.

    PubMed

    Shen, Yaou; Zhang, Yongzhong; Chen, Jie; Lin, Haijian; Zhao, Maojun; Peng, Huanwei; Liu, Li; Yuan, Guangsheng; Zhang, Suzhi; Zhang, Zhiming; Pan, Guangtang

    2013-03-01

    Lead (Pb) has become one of the most abundant heavy metal pollutants of the environment. With its large biomass, maize could be an important object for studying the phytoremediation of Pb-contaminated soil. In our previous research, we screened 19 inbred lines of maize for Pb concentration, and line 178 was identified to be a hyperaccumulator for Pb in both the roots and aboveground parts. To identify important genes and metabolic pathways related to Pb accumulation and tolerance, line 178 was underwent genome expression profile under Pb stress and a control (CK). A total of approximately 11 million cDNA tags were sequenced and 4 665 539 and 4 936 038 clean tags were obtained from the libraries of the test and CK, respectively. In comparison to CK, 2379 and 1832 genes were identified up- or downregulated, respectively, more than fivefolds under Pb stress. Interestingly, all the genes were related to cellular processes and signaling, information storage and processing or metabolism functions. Particularly, the genes involved in posttranslational modification, protein turnover and chaperones; signal transduction, carbohydrate transport and metabolism; and lipid transport and metabolism significantly changed under the treatment. In addition, seven pathways including ribosome, photosynthesis, and carbon fixation were affected significantly, with 118, 12, 34, 21, 18, 72 and 43 differentially expressed genes involved. The significant upregulation of the ribosome pathway may reveal an important secret for Pb tolerance of line 178. And the sharp increase of laccase transcripts and metal ion transporters were suggested to account in part for Pb hyperaccumulation in the line.

  1. Expression of escherichia coli otsA in a Saccharomyces cerevisiae tps1 mutant restores trehalose 6-phosphate levels and partly restores growth and fermentation with glucose and control of glucose influx into glycolysis.

    PubMed

    Bonini, B M; Van Vaeck, C; Larsson, C; Gustafsson, L; Ma, P; Winderickx, J; Van Dijck, P; Thevelein, J M

    2000-08-15

    The TPS1 gene, encoding trehalose-6-phosphate synthase (TPS), exerts an essential control on the influx of glucose into glycolysis in the yeast Saccharomyces cerevisiae. The deletion of TPS1 causes an inability to grow on glucose because of a hyperaccumulation of sugar phosphates and depletion of ATP and phosphate. We show that expression of the Escherichia coli homologue, otsA, in a yeast tps1 mutant results in high TPS activity. Although the trehalose 6-phosphate (Tre6P) level during exponential growth on glucose was at least as high as in a wild-type yeast strain, growth on glucose was only partly restored and the lag phase was much longer. Measurement of the glycolytic metabolites immediately after the addition of glucose showed that in spite of a normal Tre6P accumulation there was still a partial hyperaccumulation of sugar phosphates. Strong elevation of the Tre6P level by the additional deletion of the TPS2 gene, which encodes Tre6P phosphatase, was not able to cause a strong decrease in the sugar phosphate levels in comparison with the wild-type strain. In addition, in chemostat experiments the short-term response to a glucose pulse was delayed, but normal metabolism was regained over a longer period. These results show that Tre6P synthesis from a heterologous TPS enzyme can to some extent restore the control of glucose influx into glycolysis and growth on glucose in yeast. However, they also indicate that the yeast TPS enzyme, as opposed to the E. coli otsA gene product, is able to increase the efficiency of the Tre6P control on glucose influx into yeast glycolysis.

  2. Phytoremediation of Ionic and Methyl Mercury Pollution

    SciTech Connect

    Meagher, Richard B.

    2005-06-01

    Phytoremediation is defined as the use of plants to extract, resist, detoxify, and/or sequester toxic environmental pollutants. The long-term goal of the proposed research is to develop and test highly productive, field-adapted plant species that have been engineered for the phytoremediation of mercury. A variety of different genes, which should enable plants to clean mercury polluted sites are being tested as tools for mercury phytoremediation, first in model laboratory plants and then in potential field species. Several of these genes have already been shown to enhance mercury phytoremediation. Mercury pollution is a serious, world-wide problem affecting the health of human and wildlife populations. Environmentally, the most serious mercury threat is the production of methylmercury (CH3Hg+) by native bacteria at mercury contaminated wetland sites. Methylmercury is inherently more toxic than metallic (Hg(0)) or ionic (Hg(II)) mercury, and because methylmercury is prolifically biomagnified up the food chain, it poses the most immediate danger to animal populations. We have successfully engineered two model plants, Arabidopsis and tobacco, to use the bacterial merB gene to convert methylmercury to less toxic ionic mercury and to use the bacterial merA gene to further detoxify ionic mercury to the least toxic form of mercury, metallic mercury. Plants expressing both MerA and MerB proteins detoxify methylmercury in two steps to the metallic form. These plants germinate, grow, and set seed at normal growth rates on levels of methylmercury or ionic mercury that are lethal to normal plants. Our newest efforts involve engineering plants with several additional bacterial and plant genes that allow for higher levels of mercury resistance and mercury hyperaccumulation. The potential for these plants to hyperaccumulate mercury was further advanced by developing constitutive, aboveground, and root-specific gene expression systems. Our current strategy is to engineer plants to

  3. Arsenic speciation in tissues of the hyperacumulator P. calomelanos var. austroamericana using x-ray absorption spectroscopy.

    SciTech Connect

    Heald, S. M.; Kachenko, A.; Graefe, M.; Singh, B.; X-Ray Science Division; Univ. of Sydney

    2010-06-15

    The fate and chemical speciation of arsenic (As) uptake, translocation and storage by the As hyperaccumulating fern Pityogramma calomelanos var. austroamericana (Pteridaceae) were examined using inductively coupled plasma-atomic emission spectrometry (ICP-AES) and synchrotron-based {mu}-X-ray absorption near edge structure ({mu}-XANES) and {mu}-X-ray fluorescence ({mu}-XRF) spectroscopies. Chemical analysis revealed total As concentration was ca. 6.5 times greater in young fronds (5845 mg kg {sup -1} dry weight) than in old frons (903 mg kg {sup -1} DW) pinnae, As concentration decreased from the base (6822 mg kg {sup -1} DW) to the apex (4301 mg kg {sup -1}DW) of the fronds. The results from {mu}-XANES and {mu}-XRF of living tissues suggested that more than 60% of arsenate (As{sup v}) absorbed was reduced to arsenite (As{sup III}) in roots, prior to transport through vascular tissues as As{sup v} and As{sup III}. In pinnules, As{sup III} was the predominate redox species (72-90%), presumably as solvated, oxygen coordinated compounds. The presence of putative As{sup III}-sulphide (S{sup -2}) coordinationthroughout the fern tissues (4-25%) suggests that S{sup 2-} functional groups may contribute in the biochemical reduction of As{sup v} to As{sup III} during uptake and transport at a whole plant level. Organic arsenicals and thiol-rich compounds were not detected in the species and are unlikely to play a role in As hyperaccumulation in this fern. The study provides important insights into homeostatic regulation of As following As uptake in P. calomelanos var. austroamericana.

  4. Physiological responses of the hybrid larch (Larix × eurolepis Henry) to cadmium exposure and distribution of cadmium in plantlets.

    PubMed

    Bonet, Amandine; Lelu-Walter, Marie-Anne; Faugeron, Céline; Gloaguen, Vincent; Saladin, Gaëlle

    2016-05-01

    Phytoextraction of Cd is a growing biotechnology although we currently know few Cd hyperaccumulators, i.e., plant species able to accumulate at least 0.1 mg Cd g(-1) dry weight in aerial organs. Owing their deep root system and high biomass, trees are more and more preferred to herbaceous species for phytoextraction. Assuming that conifers could be relevant models under cold climates, we investigated cadmium tolerance of the hybrid larch Larix × eurolepis Henry (Larix decidua × Larix kaempferi) and the efficiency of this species to store this metal. In vitro grown larches were chosen in order to reduce time of exposure and to more rapidly evaluate their potential efficiency to accumulate Cd. One-month-old plantlets were exposed for 2 and 4 weeks to 250 and 500 μM Cd. Results showed that they tolerated a 4-week exposure to 250 μM Cd, whereas the content of photosynthetic pigment strongly dropped in plantlets growing in the presence of 500 μM Cd. In the presence of 250 μM Cd, shoot growth slightly decreased but photosynthetic pigment and total soluble carbohydrate contents were not modified and no lipid peroxidation was detected. In addition, these plantlets accumulated proline, particularly in shoots (two to three times more than control). In roots, Cd concentration in the intracellular fraction was always higher than in the cell wall fraction contrary to shoots where Cd concentration in the cell wall fraction increased with time and Cd concentration in the medium. In shoots, Cd concentration was lower than in roots with a ratio of 0.2 after 4 weeks of exposure but stayed around 0.2 mg g(-1) dry weight, thus a value higher than the threshold requested for Cd hyperaccumulators. Hybrid larch would thus be a relevant candidate for field test of Cd phytoextraction.

  5. Wild food plants used by the Tibetans of Gongba Valley (Zhouqu county, Gansu, China)

    PubMed Central

    2014-01-01

    Background The ethnobotany of Tibetans is a seriously under-studied topic. The aim of the study was to investigate knowledge and use of wild food plants in a valley inhabited by Tibetans in the Gannan Tibetan Autonomous Region. Methods The field research was carried out in a wooded mountain valley in 9 neighbouring villages the Zhouqu (Brugchu) county, and comprised 17 interviews with single informants and 14 group interviews, involving 122 people altogether. Results We recorded the use of 81 species of vascular plants from 41 families. Fruits formed the largest category, with 42 species, larger than the wild greens category, with 36 species. We also recorded the culinary use of 5 species of edible flowers, 7 species with underground edible organs and 5 taxa of fungi. On average, 16.2 edible taxa were listed per interview (median – 16). Green vegetables formed the largest category of wild foods (mean – 8.7 species, median – 9 species), but fruits were listed nearly as frequently (mean – 6.9, median – 6). Other categories were rarely mentioned: flowers (mean – 0.2, median – 0), underground edible parts (mean – 0.3, median – 0) and mushrooms (mean – 1.5, – median 1). Wild vegetables are usually boiled and/or fried and served as side-dishes (cai). They are often lacto-fermented. Wild fruits are mainly collected by children and eaten raw, they are not stored for further use. The most widely used wild vegetables are: Eleuterococcus spp., Pteridium aquilinum, Helwingia japonica, Aralia chinensis, Allium victorialis, Pteridium aquilinum, Ixeris chinensis, Thlaspi arvense and Chenopodium album. The culinary use of Caltha palustris as a green vegetable is very interesting. In its raw state, marsh marigold is a toxic plant, due to the presence of protoanemonin. In this area it is dried or lactofermented before use. The most commonly eaten fruits are: Pyrus xerophila, Prunus salicina, Berchemia sinica, Rubus spp. and Eleagnus umbellata. Conclusions The

  6. A Phytoremediation Strategy for Arsenic

    SciTech Connect

    Meagher, Richard B.

    2005-06-01

    A Phytoremediation Strategy for Arsenic Progress Report May, 2005 Richard B. Meagher Principal Investigator Arsenic pollution affects the health of several hundred millions of people world wide, and an estimated 10 million Americans have unsafe levels of arsenic in their drinking water. However, few environmentally sound remedies for cleaning up arsenic contaminated soil and water have been proposed. Phytoremediation, the use of plants to extract and sequester environmental pollutants, is one new technology that offers an ecologically sound solution to a devastating problem. We propose that it is less disruptive to the environment to harvest and dispose of several thousand pounds per acre of contaminated aboveground plant material, than to excavate and dispose of 1 to 5 million pounds of contaminated soil per acre (assumes contamination runs 3 ft deep). Our objective is to develop a genetics-based phytoremediation strategy for arsenic removal that can be used in any plant species. This strategy requires the enhanced expression of several transgenes from diverse sources. Our working hypothesis is that organ-specific expression of several genes controlling the transport, electrochemical state, and binding of arsenic will result in the efficient extraction and hyperaccumulation of arsenic into aboveground plant tissues. This hypothesis is supported by theoretical arguments and strong preliminary data. We proposed six Specific Aims focused on testing and developing this arsenic phytoremediation strategy. During the first 18 months of the grant we made significant progress on five Specific Aims and began work on the sixth as summarized below. Specific Aim 1: Enhance plant arsenic resistance and greatly expand sinks for arsenite by expressing elevated levels of thiol-rich, arsenic-binding peptides. Hyperaccumulation of arsenic depends upon making plants that are both highly tolerant to arsenic and that have the capacity to store large amounts of arsenic aboveground

  7. Reconstitution of ethanolic fermentation in permeabilized spheroplasts of wild-type and trehalose-6-phosphate synthase mutants of the yeast Saccharomyces cerevisiae.

    PubMed

    Noubhani, A; Bunoust, O; Rigoulet, M; Thevelein, J M

    2000-07-01

    In the yeast Saccharomyces cerevisiae, TPS1-encoded trehalose-6-phosphate synthase (TPS) exerts an essential control on the influx of glucose into glycolysis, presumably by restricting hexokinase activity. Deletion of TPS1 results in severe hyperaccumulation of sugar phosphates and near absence of ethanol formation. To investigate whether trehalose 6-phosphate (Tre6P) is the sole mediator of hexokinase inhibition, we have reconstituted ethanolic fermentation from glucose in permeabilized spheroplasts of the wild-type, tps1Delta and tps2Delta (Tre6P phosphatase) strains. For the tps1Delta strain, ethanol production was significantly lower and was associated with hyperaccumulation of Glu6P and Fru6P. A tps2Delta strain shows reduced accumulation of Glu6P and Fru6P both in intact cells and in permeabilized spheroplasts. These results are not consistent with Tre6P being the sole mediator of hexokinase inhibition. Reconstitution of ethanolic fermentation in permeabilized spheroplasts with glycolytic intermediates indicates additional target site(s) for the Tps1 control. Addition of Tre6P partially shifts the ethanol production rate and the metabolite pattern in permeabilized tps1Delta spheroplasts to those of the wild-type strain, but only with glucose as substrate. This is observed at a very high ratio of glucose to Tre6P. Inhibition of hexokinase activity by Tre6P is less efficiently counteracted by glucose in permeabilized spheroplasts compared to cell extracts, and this effect is largely abolished by deletion of TPS2 but not TPS1. In permeabilized spheroplasts, hexokinase activity is significantly lower in a tps2Delta strain compared to a wild-type strain and this difference is strongly reduced by additional deletion of TPS1. These results indicate that Tps1-mediated protein-protein interactions are important for control of glucose influx into yeast glycolysis, that Tre6P inhibition of hexokinase might not be competitive with respect to glucose in vivo and that also

  8. A field study on phytoremediation of a lead-contaminated soil by Eucalyptus globulus in an abandoned mine site - Alagoa, Portugal

    NASA Astrophysics Data System (ADS)

    Gerardo, R.; Kikuchi, R.

    2009-04-01

    Current engineering-based technologies used to clean up soils are very costly and need lots of work. Phytoremediation is the use of plants to remove pollutants (i.e. heavy metals) from the environment or render them harmless. In the phytoremediation process several plant species can be used to reduce the concentrations of heavy metals in contaminated soils to environmentally acceptable levels. The idea of using rare plants which hyperaccumulate metals to selectively remove and recycle excessive soil metals has increasingly been examined as a potential practical and more cost effective technology than soil replacement, solidification, or washing strategies presently used. However, most hyperaccumulator species are not suitable for phytoremediation application in the field due to their small biomass and slow growth. Cultivation of woody plants in contaminated soils has showed potential for use in phytoremediation but also it provides aesthetic improvement in the field. In this study we studied the possibility of using the approach of phytoremediation of lead by Eucalyptus globulus in a lead-contaminated soil from an abandoned mine. Although Eucalytpus globulus prefer good ecological conditions in humid temperate climates, there are few studies that have showed their great potential in contaminated areas and important biomonitors of environmental quality. A test field was set up in an abandoned mine site (Alagoa, Portugal) in order to investigate the feasibility of phytoremediation of lead by Eucalyptus globulus. The field soil was characterized as follows: humus - 2.56-7.08%, pH in the soil water - 4.50-5.10, silte - 18-15% and total Pb - 67-239 mg/kg. The soils in some areas exceed the critical value (150 mg/kg) according with Portuguese law. Eucalytus globulus growing on the abandoned mine, contaminated with lead was studied. The results of shoots sample analysis (n = 15) show the total Pb levels of 0.170-0.093 mg/kg in the stem and 2.94-5.14 mg/kg in the leaves

  9. Riparian plants on mine runoff in Zimapan, Hidalgo, Mexico: Useful for phytoremediation?

    PubMed

    Carmona-Chit, Eréndira; Carrillo-González, Rogelio; González-Chávez, Ma Del Carmen A; Vibrans, Heike; Yáñez-Espinosa, Laura; Delgado-Alvarado, Adriana

    2016-09-01

    Dispersion and runoff of mine tailings have serious implications for human and ecosystem health in the surroundings of mines. Water, soils and plants were sampled in transects perpendicular to the Santiago stream in Zimapan, Hidalgo, which receives runoff sediments from two acidic and one alkaline mine tailing. Concentrations of potentially toxic elements (PTE) were measured in water, soils (rhizosphere and non-rhizosphere) and plants. Using diethylenetriaminepentaacetic acid (DTPA) extractable concentrations of Cu, Zn, Ni, Cd and Pb in rhizosphere soil, the bioconcentration and translocation factors were calculated. Ruderal annuals formed the principal element of the herbaceous vegetation. Accumulation was the most frequent strategy to deal with high concentrations of Zn, Cu, Ni, Cd and Pb. The order of concentration in plant tissue was Zn>Pb>Cu>Ni>Cd. Most plants contained concentrations of PTE considered as phytotoxic and behaved as metal tolerant species. Rorippa nasturtium-aquaticum accumulated particularly high concentrations of Cu. Parietaria pensylvanica and Commelina diffusa, common tropical weeds, behaved as Zn hyperaccumulators and should be studied further.

  10. Differential expression and regulation of iron-regulated metal transporters in Arabidopsis halleri and Arabidopsis thaliana--the role in zinc tolerance.

    PubMed

    Shanmugam, Varanavasiappan; Lo, Jing-Chi; Wu, Chia-Lin; Wang, Shan-Li; Lai, Chong-Cheong; Connolly, Erin L; Huang, Jing-Ling; Yeh, Kuo-Chen

    2011-04-01

    To avoid zinc (Zn) toxicity, plants have developed a Zn homeostasis mechanism to cope with Zn excess in the surrounding soil. In this report, we uncovered the difference of a cross-homeostasis system between iron (Fe) and Zn in dealing with Zn excess in the Zn hyperaccumulator Arabidopsis halleri ssp. gemmifera and nonhyperaccumulator Arabidopsis thaliana. Arabidopsis halleri shows low expression of the Fe acquisition and deficiency response-related genes IRT1 and IRT2 compared with A. thaliana. In A. thaliana, lowering the expression of IRT1 and IRT2 through the addition of excess Fe to the medium increases Zn tolerance. Excess Zn induces significant Fe deficiency in A. thaliana and reduces Fe accumulation in shoots. By contrast, the accumulation of Fe in shoots of A. halleri was stable under various Zn treatments. Root ferric chelate reductase (FRO) activity and expression of FIT are low in A. halleri compared with A. thaliana. Overexpressing a ZIP family member IRT3 in irt1-1, rescues the Fe-deficient phenotype. A fine-tuned Fe homeostasis mechanism in A. halleri maintains optimum Fe level by Zn-regulated ZIP transporters and prevents high Zn uptake through Fe-regulated metal transporters, and in part be responsible for Zn tolerance.

  11. Assessment of heavy metals accumulation by spontaneous vegetation: Screening for new accumulator plant species grown in Kettara mine-Marrakech, Southern Morocco.

    PubMed

    Midhat, Laila; Ouazzani, Naaila; Esshaimi, Mouhsine; Ouhammou, Ahmed; Mandi, Laila

    2017-02-01

    The present paper aims to perform a screening of native plants growing in Kettara mine-Marrakech (Southern Morocco) for its phytoremediation. Plants and soil samples were collected and analyzed for Pb, Zn, Cu and Cd concentrations at several sites in the mine. The results showed that the soil in the vicinity of Kettara mine is deficient in major elements and contain toxic levels of metals. Spontaneously growing native plants were botanically identified and then classified into 21 species and 14 families. Significant difference was observed among the average concentrations of four heavy metals (Pb, Zn, Cu and Cd) in plants (p ≤ 0.05). Six plants of 21 species namely Hammada scoparia (Pomel) Iljin, Hirschfeldia incana (L.) Lagreze-Fossat, Lamarckia aurea (L.) Moench, Calendula algeriensis Boiss. & Reuter, Aizoon hispanicum L. and Melilotus sulcata Desf. were considered as the best-performing specimens due to their high ability to accumulate multiple metals in their shoots and roots without sustaining toxicity. This was confirmed by the transfer factors generally higher than 1. Using the most common criteria to classify the hyperaccumulator plants, these species can be classified as new accumulator plants of many heavy metals and be potentially used as remediation tools of metal-contaminated sites.

  12. Restoration of red mud deposits by naturally growing vegetation.

    PubMed

    Mishra, Tripti; Singh, N B; Singh, Nandita

    2017-05-04

    Disposal of red mud (RM) poses serious environmental problems such as wind erosion, air and water pollution. To overcome these problems, effective restoration of the disposal land through naturally growing vegetation is a sustainable and economical approach. The present study involved estimation of frequency (F), density (D), abundance (Ab), and important value index (IVI) of natural flora on abandoned RM sites in order to assess their metal toxicity tolerance capacity. Based on visual observations and highest IVI, S. Asper and S. punicea were identified as effective ecological tools for the restoration of barren RM sites. From the study, remarkable differences were observed between non-rhizospheric and rhizospheric RM of both species. These rhizospheric RM analyses confirm the ability of S. asper and S. punicea for enhancing the biological activities of abandoned RM. Translocation factor (TF) of iron was maximum (2.58) in S. asper, and bioconcentration factor (BCF) was found maximum (1.25) in S. punicea, but both TF (2.58) and BCF (1.35) were high in S. asper. Therefore, this plant could be reported as an iron hyperaccumulator plant. These results suggest that these plant species can be exploited for effective restoration of RM deposited land without any inputs or maintenance.

  13. Overexpressing both ATP sulfurylase and selenocysteine methyltransferase enhances selenium phytoremediation traits in Indian mustard.

    PubMed

    LeDuc, Danika L; AbdelSamie, Manal; Móntes-Bayon, Maria; Wu, Carol P; Reisinger, Sarah J; Terry, Norman

    2006-11-01

    A major goal of our selenium (Se) phytoremediation research is to use genetic engineering to develop fast-growing plants with an increased ability to tolerate, accumulate, and volatilize Se. To this end we incorporated a gene (encoding selenocysteine methyltransferase, SMT) from the Se hyperaccumulator, Astragalus bisulcatus, into Indian mustard (LeDuc, D.L., Tarun, A.S., Montes-Bayón, M., Meija, J., Malit, M.F., Wu, C.P., AbdelSamie, M., Chiang, C.-Y., Tagmount, A., deSouza, M., Neuhierl, B., Böck, A., Caruso, J., Terry, N., 2004. Overexpression of selenocysteine methyltransferase in Arabidopsis and Indian mustard increases selenium tolerance and accumulation Plant Physiol. 135, 377-383.). The resulting transgenic plants successfully enhanced Se phytoremediation in that the plants tolerated and accumulated Se from selenite significantly better than wild type. However, the advantage conferred by the SMT enzyme was much less when Se was supplied as selenate. In order to enhance the phytoremediation of selenate, we developed double transgenic plants that overexpressed the gene encoding ATP sulfurylase (APS) in addition to SMT, i.e., APSxSMT. The results showed that there was a substantial improvement in Se accumulation from selenate (4 to 9 times increase) in transgenic plants overexpressing both APS and SMT.

  14. Characterizations of bio-accumulations, subcellular distribution and chemical forms of cesium in Brassica juncea, and Vicia faba.

    PubMed

    Fu, Qian; Lai, Jin-long; Tao, Zong-ya; Han, Na; Wu, Guo

    2016-04-01

    We aim to investigate the tolerance and enrichment mechanism of cesium (Cs) in hyperaccumulation plants. In this study, Brassica juncea and Vicia faba were subjected to varying doses of Cs for 21 days to investigate the differences in bio-accumulations, subcellular distribution and chemical forms of Cs in two cultivars by differential centrifugation, and extraction of Cs in different chemical forms, respectively. The results showed that 49.87%-61.08% of the Cs were in the leaf of B. juncea, while in V. faba, 1.58%-79.29% of the Cs was in the root. The translocation factor (TF) arrived 2.79 to 3.71 in B. juncea, while it only reached 0.26 to 0.62 in V. faba. Cs subcellular distribution of the two plants was in sequence as follows: soluble fraction > cell wall > organelles. Cs was more easily distributed to metal-sensitive fractions of V. faba. The inorganic Cs (F-ethanol), and water-soluble Cs (F-dH2O) are the main existing types of Cs in the two plants. In B. juncea, the relative content of inorganic Cs, and organic acids/CsH2PO4 (F-dH2O) were higher than that of V. faba in the stem. This suggests that Cs may induce related transporter gene expression (such as phosphate transporter, organic cation, high affinity nitrate transporter, amino acid permease, etc.) to help the transport of Cs between root to shoot.

  15. Exploring the Influence of Environmental Factors on Bacterial Communities within the Rhizosphere of the Cu-tolerant plant, Elsholtzia splendens

    NASA Astrophysics Data System (ADS)

    Jiang, Longfei; Song, Mengke; Yang, Li; Zhang, Dayi; Sun, Yingtao; Shen, Zhenguo; Luo, Chunling; Zhang, Gan

    2016-10-01

    Bacterial communities of rhizospheric soils play an important role in the tolerance and uptake of metal-tolerant/hyperaccumulating plants to metals, e.g. the Cu-tolerant Elsholtzia splendens native to China. In this work, pyrosequencing of the bacterial 16S rRNA gene was firstly applied to investigate the rhizospheric bacterial community of E. splendens grown at Cu contaminated sites. The 47 phyla including 11 dominant phyla (>1%) in E. splendens rhizosphere were presented. The effects of Cu and other environmental factors (total organic carbon, total nitrogen and pH) on the rhizospheric bacterial community were studied comprehensively. The phyla abundances were affected by the environmental factors to different extent, and we found pH, instead of Cu concentration, influenced UniFrac distance significantly and was identified as the most important environmental factor affecting bacterial community. In addition, the influence of environmental factors on gene profiles was explored according to the predicted metagenomes obtained by PICRUSt (phylogenetic investigation of communities by reconstruction of unobserved states). Our study illustrates a view about Cu-tolerant E. splendens rhizospheric bacterial communities (composition, diversity and gene profiles) and their influencing factors, giving a hand for the understanding on bacterial community is formed and affected in rhizosphere.

  16. Phenolic compounds responding to zinc and/or cadmium treatments in Gynura pseudochina (L.) DC. extracts and biomass.

    PubMed

    Mongkhonsin, Bodin; Nakbanpote, Woranan; Hokura, Akiko; Nuengchamnong, Nitra; Maneechai, Suthira

    2016-12-01

    Gynura pseudochina (L.) DC. is a Zn/Cd hyperaccumulative plant. In an in vivo system under controlled plant age, this research reveals that phenolic compounds and lignification play beneficial roles in protecting G. pseudochina from exposure to an excess of Zn and/or Cd, and Zn reduces Cd toxicity under the dual treatments. The total phenolic content (TPC), total flavonoid content (TFC), and half-maximal inhibitory concentration (IC50) values correspond to the metal dose-response curves. Liquid chromatography-electrospray ionization-quadrupole time of flight-tandem mass spectrometry (LC-ESI-QTOF-MS/MS) is used to characterize phenolic compounds and their glycosides, which could play roles in antioxidant activities and in the esterification of the cell wall, especially derivatives of p-coumaric and caffeic acid. Confocal laser scanning microscopy (CLSM) and micro X-ray fluorescence (μ-XRF) imaging revealed that the accumulation of Zn and Cd in the cell wall involves flavonoid compounds. Low extractable pools of Cd and Zn in the leaf extracts indicate that these elements are tightly bound to the plant biomass structures. The bulk X-ray absorption near edge structure (XANES) spectra indicate that Zn(2+) and Cd(2+) dominate with O and S ligands, which could be provided by cell walls, phenolic compounds, and sulphur protein. Consequently, the benefit of these results is to support the growth of G. pseudochina for phytoremediation in a Zn- and/or Cd-contaminated site.

  17. Antimony in the Soil-Plant System in an Sb Mining/Smelting Area of Southwest China.

    PubMed

    Ning, Zengping; Xiao, Tangfu; Xiao, Enzong

    2015-01-01

    The distribution, bioavailability, and accumulation of antimony (Sb) at the interface of rhizospheric soils and indigenous plants from a large Sb mining/smelting area in Southwest China were explored. Results showed that the local soil was severely polluted by Sb, and the aluminum magnesium silicate minerals and the carbonate fraction may mainly contribute to bound Sb. The sequential extraction results of soil samples revealed that the portion of bioavailable Sb was low, but the bioavailable Sb concentration was up to 67.2 mg/kg, due to high total Sb concentrations in the soil. The Sb content in local plants showed a wide range, from 21 to 21148 mg/kg. The species of Chenopodium album Linn., Sedum emarginatum Migo, and Sedum lineare Thunb showed high accumulation of Sb at levels of above 1000 mg/kg. The Sb contents in the tissues for most plants decreased with the order of root > leaf > stem. The bioaccumulation coefficients and/or the biological transfer factors for most plants were less than 1. All of the studied plant species were not identified as Sb-hyperaccumulators, but the species of Chenopodium album Linn., Sedum emarginatum Migo, and Sedum lineare Thunb could be applied as alternative plants for phytoremediating Sb-polluted soils.

  18. Differential antimicrobial activity of silver nanoparticles to bacteria Bacillus subtilis and Escherichia coli, and toxicity to crop plant Zea mays and beneficial B. subtilis-inoculated Z. mays

    NASA Astrophysics Data System (ADS)

    Doody, Michael A.; Wang, Dengjun; Bais, Harsh P.; Jin, Yan

    2016-10-01

    As silver nanoparticles (AgNPs) have become increasingly used in commercial antimicrobial agents and industrial and military products, concerns are increasing over their broad environmental and health impacts and risks because they are finding their way to the environment. This study was designed to quantify the antimicrobial activity of citrate-coated AgNPs (c-AgNPs; transmission electron microscope size of 44.9 ± 7.2 nm) to two species of bacteria, i.e., Gram-positive Bacillus subtilis and Gram-negative Escherichia coli, and toxicity to a major crop plant Zea mays and beneficial bacteria-inoculated plant (i.e., B. subtilis-inoculated Z. mays symbiont). Our results reveal that the exposure of c-AgNPs significantly inhibited bacteria growth and altered their growth kinetics. Z. mays experienced significant sublethal effects including reduced root length and biomass, and hyper-accumulation of Ag in roots. The beneficial interactions between B. subtilis and Z. mays were weakened as well because both species suffered sublethal effects. Potential mechanisms leading to the antimicrobial activity and toxicity of c-AgNPs to the bacteria, plant, and plant-bacteria symbiont examined in this study were discussed. Taken together, our findings advance the current knowledge of AgNPs antimicrobial property or toxicity to bacteria, crop plant, and beneficial plant-bacteria symbiotic interaction, which is a critical component for NPs environmental impact and risk assessment.

  19. Effects of Phosphate on Arsenate Uptake and Translocation in Nonmetallicolous and Metallicolous Populations of Pteris Vittata L. Under Solution Culture.

    PubMed

    Wu, Fuyong; Wu, Shengchun; Deng, Dan; Wong, Ming Hung

    2015-01-01

    An arsenic hyperaccumulator, Pteris vittata L., is common in nature and could occur either on As-contaminated soils or on uncontaminated soils. However, it is not clear whether phosphate transporter play similar roles in As uptake and translocation in nonmetallicolous and metallicolous populations of P. vittata. Five populations were used to investigate effects of phosphate on arsenate uptake and translocation in the plants growing in 1.2 L 20% modified Hoagland's nutrient solution containing either 100 μM phosphate or no phosphate and 10 μM arsenate for 1, 2, 6, 12, 24 h, respectively. The results showed that the nonmetallicolous populations accumulated apparently more As in their fronds and roots than the metallicolous populations at both P supply levels. Phosphate significantly (P < 0.01) decreased frond and root concentrations of As during short time solution culture. In addition, the effects of phosphate on As translocation in P. vittata varied among different time-points during time-course hydroponics (1-24 h). The present results indicated that the inhibitory effect of phosphate on arsenate uptake was larger in the three nonmetallicolous populations than those in the two metallicolous populations of P. vittata.

  20. Cadmium tolerance and accumulation of Elsholtzia argyi origining from a zinc/lead mining site - a hydroponics experiment.

    PubMed

    Li, Siliang; Wang, Fengping; Ru, Mei; Ni, Wuzhong

    2014-01-01

    In this study, a hydroponics experiment was conducted to investigate the characteristics of Cd tolerance and accumulation of Elsholtzia argyi natively growing on the soil with high levels of heavy metals in a Zn/Pb mining site. Seedlings of E. argyi grown for 4 weeks and then were treated with 0(CK), 5,10,15, 20, 25, 30, 40, 50,100 umM Cd for 21 days. Each treatment had three replications. No visual toxic symptoms on shoots of E. argyi were observed at Cd level < or = 50 muM. The results indicated that the dry biomass of each tissue and the whole plants of the treatments with < or =40 umM cadmium were similar to that of the control, implying that E. argyi was a cadmium tolerant plant. The results also showed that the shoot Cd concentration significantly (P < 0.05) increased with the increase in the Cd level in nutrient solution. The shoot Cd concentration of the treatment with 40 umM Cd was as high as 237.9 mg kg(-1), which was higher than 100 mg kg(-1), normally used as the threshold concentration for identifying the Cd hyperaccumulating plant. It could be concluded that E. argyi was a Cd tolerant and accumulating plant species.

  1. Capacity of the aquatic fern (Salvinia minima Baker) to accumulate high concentrations of nickel in its tissues, and its effect on plant physiological processes.

    PubMed

    Fuentes, Ignacio I; Espadas-Gil, Francisco; Talavera-May, Carlos; Fuentes, Gabriela; Santamaría, Jorge M

    2014-10-01

    An experiment was designed to assess the capacity of Salvinia minima Baker to uptake and accumulate nickel in its tissues and to evaluate whether or not this uptake can affect its physiology. Our results suggest that S. minima plants are able to take up high amounts of nickel in its tissues, particularly in roots. In fact, our results support the idea that S. minima might be considered a hyper-accumulator of nickel, as it is able to accumulate 16.3 mg g(-1) (whole plant DW basis). Our results also showed a two-steps uptake pattern of nickel, with a fast uptake of nickel at the first 6 to 12h of being expose to the metal, followed by a slow take up phase until the end of the experiment at 144 h. S. minima thus, may be considered as a fern useful in the phytoremediation of residual water bodies contaminated with this metal. Also from our results, S. minima can tolerate fair concentrations of the metal; however, at concentrations higher than 80 μM Ni (1.5 mg g(-1) internal nickel concentration), its physiological performance can be affected. For instance, the integrity of cell membranes was affected as the metal concentration and exposure time increased. The accumulation of high concentrations of internal nickel did also affect photosynthesis, the efficiency of PSII, and the concentration of photosynthetic pigments, although at a lower extent.

  2. Feasibility Study of Phragmites karka and Christella dentata Grown in West Bengal as Arsenic Accumulator.

    PubMed

    Raj, Anshita; Jamil, Sarah; Srivastava, Pankaj Kumar; Tripathi, Rudra Deo; Sharma, Yogesh Kumar; Singh, Nandita

    2015-01-01

    A survey was undertaken, in arsenic (As) contaminated area of the Nadia district, West Bengal, India, to find native As accumulator plants. As was determined both in soil and plant parts. The results showed that the mean translocation factor of Pteris vittata L, Phragmites karka (Cav.) Trin. Ex. Steud and Christella dentata Forssk were higher than 1. It thus appeared that these plants can be efficient accumulators of As. Phytoremediation ability of C. dentata and P. karka was evaluated and compared with known As-hyperaccumulators -P. vittata and Adiantum capillus veneris L. Plants were grown in the As spiked soil (25, 50, 75 and 100 mg kg(-1)). As accumulation was found to be highest in P. vittata, 117.18 mg kg(-1) in leaf at 100 mg kg(-1) As treatment, followed by A. capillus veneris, P. karka and C. dentata being 74, 83.87 and 40.36 mg kg(-1), respectively. Lipid peroxidation increased after As exposure in all plants. However, the antioxidant enzyme activity and molecules concentration also increased which helped the plants to overcome As-induced oxidative stress. The study indicates that P. karka and C. dentata could be considered as As-accumulators and find application for As-phytoextraction in field conditions.

  3. Enhanced Heavy Metal Tolerance and Accumulation by Transgenic Sugar Beets Expressing Streptococcus thermophilus StGCS-GS in the Presence of Cd, Zn and Cu Alone or in Combination.

    PubMed

    Liu, Dali; An, Zhigang; Mao, Zijun; Ma, Longbiao; Lu, Zhenqiang

    2015-01-01

    Phytoremediation is a promising means of ameliorating heavy metal pollution through the use of transgenic plants as artificial hyperaccumulators. A novel Streptococcus thermophilus γ-glutamylcysteine synthetase-glutathione synthetase (StGCS-GS) that synthesizes glutathione (GSH) with limited feedback inhibition was overexpressed in sugar beet (Beta vulgaris L.), yielding three transgenic lines (s2, s4 and s5) with enhanced tolerance to different concentrations of cadmium, zinc and copper, as indicated by their increased biomass, root length and relative growth compared with wild-type plants. Transgenic sugar beets accumulated more Cd, Zn and Cu ions in shoots than wild-type, as well as higher GSH and phytochelatin (PC) levels under different heavy metal stresses. This enhanced heavy metal tolerance and increased accumulation were likely due to the increased expression of StGCS-GS and consequent overproduction of both GSH and PC. Furthermore, when multiple heavy metal ions were present at the same time, transgenic sugar beets overexpressing StGCS-GS resisted two or three of the metal combinations (50 μM Cd-Zn, Cd-Cu, Zn-Cu and Cd-Zn-Cu), with greater absorption in shoots. Additionally, there was no obvious competition between metals. Overall, the results demonstrate the explicit role of StGCS-GS in enhancing Cd, Zn and Cu tolerance and accumulation in transgenic sugar beet, which may represent a highly promising new tool for phytoremediation.

  4. From biodiversity to catalytic diversity: how to control the reaction mechanism by the nature of metallophytes.

    PubMed

    Escande, Vincent; Olszewski, Tomasz K; Grison, Claude

    2015-04-01

    Phytoextraction is widely used for the reclamation of degraded sites, particularly to remove trace metals from contaminated soils. Whereas this technique demonstrates several advantages, the biomass resulting from phytoextraction processes is highly enriched in metallic elements and constitutes therefore a problematic waste. We show here that this biomass can be used for the preparation of novel polymetallic extracts, with high potential as catalysts or reagents in organic synthesis. This new concept of ecocatalysis constitutes an innovative recycling of metallic elements whose current known reserves could be exhausted in the coming decades. The ecocatalysts Eco-Zn and Eco-Ni prepared respectively from Zn and Ni hyperaccumulating plants display two distinct chemical reactivities, starting from the same substrates. Eco-Zn led to the formation of esters of commercial interest for the fragrance industry, following a hydro-acyloxy-addition reaction pathway. In contrast, Eco-Ni afforded chlorinated products thank to the hydrochlorination of alkenes. Both ecocatalysts allowed the synthesis of valuable products in high yields through methodologies in line with the spirit of sustainable chemistry.

  5. Subcellular metal imaging identifies dynamic sites of Cu accumulation in Chlamydomonas

    DOE PAGES

    Hong-Hermesdorf, Anne; Miethke, Marcus; Gallaher, Sean D.; ...

    2014-10-26

    Here we identified a Cu-accumulating structure with a dynamic role in intracellular Cu homeostasis. During Zn limitation, Chlamydomonas reinhardtii hyperaccumulates Cu, a process dependent on the nutritional Cu sensor CRR1, but it is functionally Cu deficient. Visualization of intracellular Cu revealed major Cu accumulation sites coincident with electron-dense structures that stained positive for low pH and polyphosphate, suggesting that they are lysosome-related organelles. Nano-secondary ion MS showed colocalization of Ca and Cu, and X-ray absorption spectroscopy was consistent with Cu+ accumulation in an ordered structure. Zn resupply restored Cu homeostasis concomitant with reduced abundance of these structures. Cu isotope labelingmore » demonstrated that sequestered Cu+ became bioavailable for the synthesis of plastocyanin, and transcriptome profiling indicated that mobilized Cu became visible to CRR1. Cu trafficking to intracellular accumulation sites may be a strategy for preventing protein mismetallation during Zn deficiency and enabling efficient cuproprotein metallation or remetallation upon Zn resupply.« less

  6. Subcellular metal imaging identifies dynamic sites of Cu accumulation in Chlamydomonas

    SciTech Connect

    Hong-Hermesdorf, Anne; Miethke, Marcus; Gallaher, Sean D.; Kropat, Janette; Dodani, Sheel C.; Chan, Jefferson; Barupala, Dulmini; Domaille, Dylan W.; Shirasaki, Dyna I.; Loo, Joseph A.; Weber, Peter K.; Pett-Ridge, Jennifer; Stemmler, Timothy L.; Chang, Christopher J.; Merchant, Sabeeha S.

    2014-10-26

    Here we identified a Cu-accumulating structure with a dynamic role in intracellular Cu homeostasis. During Zn limitation, Chlamydomonas reinhardtii hyperaccumulates Cu, a process dependent on the nutritional Cu sensor CRR1, but it is functionally Cu deficient. Visualization of intracellular Cu revealed major Cu accumulation sites coincident with electron-dense structures that stained positive for low pH and polyphosphate, suggesting that they are lysosome-related organelles. Nano-secondary ion MS showed colocalization of Ca and Cu, and X-ray absorption spectroscopy was consistent with Cu+ accumulation in an ordered structure. Zn resupply restored Cu homeostasis concomitant with reduced abundance of these structures. Cu isotope labeling demonstrated that sequestered Cu+ became bioavailable for the synthesis of plastocyanin, and transcriptome profiling indicated that mobilized Cu became visible to CRR1. Cu trafficking to intracellular accumulation sites may be a strategy for preventing protein mismetallation during Zn deficiency and enabling efficient cuproprotein metallation or remetallation upon Zn resupply.

  7. Different Heavy Metal Accumulation Strategies of Epilithic Lichens Colonising Artificial Post-Smelting Wastes.

    PubMed

    Rola, Kaja; Osyczka, Piotr; Kafel, Alina

    2016-02-01

    Lichens appear to be essential and effective colonisers of bare substrates including the extremely contaminated wastes of slag dumps. This study examines the metal accumulation capacity of epilithic lichens growing directly on the surface of artificial slag sinters. Four species representing different growth forms, i.e., crustose Candelariella aurella, Lecanora muralis, and Lecidea fuscoatra and fruticose Stereocaulon nanodes, were selected to evaluate the relationships between zinc, lead, cadmium, and nickel contents in their thalli and host substrates. Bioaccumulation factors of examined crustose lichens showed their propensity to hyperaccumulate heavy metals. Contrarily, concentrations of metals in fruticose thalli of S. nanodes were, as a rule, lower than in the corresponding substrates. This indicates that the growth form of thalli and degree of thallus adhesion to the substrate has a significant impact on metal concentrations in lichens colonising post-smelting wastes. Nonlinear regression models described by power functions show that at greater levels of Pb concentration in the substrate, the ability of C. aurella, L. muralis and L. fuscoatra to accumulate the metal experiences a relative decrease, whereas hyperbolic function describes a similar trend in relation to Ni content in S. nanodes. This phenomenon may be an important attribute of lichens that facilitates their colonisation of the surface of slag wastes.

  8. Mn accumulation in a submerged plant Egeria densa (Hydrocharitaceae) is mediated by epiphytic bacteria.

    PubMed

    Tsuji, Kousuke; Asayama, Takuma; Shiraki, Nozomi; Inoue, Shota; Okuda, Erina; Hayashi, Chizuru; Nishida, Kazuma; Hasegawa, Hiroshi; Harada, Emiko

    2017-01-18

    Many aquatic plants act as biosorbents, removing and recovering metals from the environment. To assess the biosorbent activity of Egeria densa, a submerged freshwater macrophyte, plants were collected monthly from a circular drainage area in Lake Biwa basin and the Mn concentrations of the plants were analyzed. Mn concentrations in these plants were generally above those of terrestrial hyperaccumulators, and were markedly higher in spring and summer than in autumn. Mn concentrations were much lower in plants incubated in hydroponic medium at various pH levels with and without Mn supplementation than in field-collected plants. The precipitation of Mn oxides on the leaves was determined by variable pressure scanning electron microscopy-energy dispersive X-ray analysis and Leucoberbelin blue staining. Several strains of epiphytic bacteria were isolated from the field-collected E. densa plants, with many of these strains, including those of the genera Acidovorax, Comamonas, Pseudomonas and Rhizobium, found to have Mn-oxidizing activity. High Mn concentrations in E. densa were mediated by the production of biogenic Mn oxide in biofilms on leaf surfaces. These findings provide new insights into plant epidermal bacterial flora that affect metal accumulation in plants and suggest that these aquatic plants may have use in Mn phytomining.

  9. Effects of copper sulfate on seedlings of Prosopis pubescens (screwbean mesquite).

    PubMed

    Zappala, Marian N; Ellzey, Joanne T; Bader, Julia; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge

    2014-01-01

    Phytoextraction is an established method of removal of heavy metals from contaminated soils worldwide. Phytoextraction is most efficient if local plants are used in the contaminated site. We propose that Prosopis pubescens (Screw bean mesquite) would be a successful phytoextractor of copper in our local soils. In order to determine the feasibility of using Screw bean mesquite, we utilized inductively-coupled plasma-optical emission spectroscopy (ICP-OES) and elemental analysis to observe the uptake of copper and the effects on macro and micro nutrients within laboratory-grown seedlings. We have previously shown that P. pubescens is a hyperaccumulator of copper in soil-grown seedlings. Light and transmission electron microscopy demonstrated death of root cells and ultrastructural changes due to the presence of copper from 50 mg/L - 600 mg/L. Ultrastructural changes included plasmolysis, starch accumulation, increased vacuolation and swollen chloroplasts with disarranged thylakoid membranes in cotyledons. Inductively coupled plasma-optical emission spectroscopy analyses of macro- and micro-nutrients revealed that the presence of copper sulfate in the growth medium of Petri-dish grown Prosopis pubescens seedlings resulted in dramatic decreases of magnesium, potassium and phosphorus. At 500-600 mg/L of copper sulfate, a substantial increase of sulfur was present in roots.

  10. Screening the phytoremediation potential of desert broom (Baccharis sarothroides Gray) growing on mine tailings in Arizona, USA

    PubMed Central

    Haque, Nazmul; Peralta-Videa, Jose R.; Jones, Gary L.; Gill, Thomas E.; Gardea-Torresdey, Jorge L.

    2008-01-01

    The metal concentrations in a copper mine tailings and Desert broom (Baccharis sarothroides Gray) plants were investigated. The metal concentrations in plants, soil cover, and tailings were determined using ICP-OES. The concentration of copper, lead, molybdenum, chromium, zinc, arsenic, nickel, and cobalt in tailings was 526.4, 207.4, 89.1, 84.5, 51.7, 49.6, 39.7, and 35.6 mg kg−1, respectively. The concentration of all elements in soil cover was 10~15% higher than that of the tailings, except for molybdenum. The concentration of copper, lead, molybdenum, chromium, zinc, arsenic, nickel, and cobalt in roots was 818.3, 151.9, 73.9, 57.1, 40.1, 44.6, 96.8, and 26.7 mg kg−1 and 1214.1, 107.3, 105.8, 105.5, 55.2, 36.9, 30.9, and 10.9 mg kg−1 for shoots, respectively. Considering the translocation factor, enrichment coefficient, and the accumulation factor, desert broom could be a potential hyperaccumulator of Cu, Pb, Cr, Zn, As, and Ni. PMID:17964035

  11. Effects of copper sulfate on seedlings of Prosopis pubescens (Screwbean mesquite)

    PubMed Central

    Zappala, Marian N.; Ellzey, Joanne T.; Bader, Julia; Peralta-Videa, Jose R.; Gardea-Torresdey, Jorge

    2013-01-01

    Phytoextraction is an established method of removal of heavy metals from contaminated soils worldwide. Phytoextraction is most efficient if local plants are used in the contaminated site. We propose that Prosopis pubescens (Screw bean mesquite) would be a successful phytoextractor of copper in our local soils. In order to determine the feasibility of using Screw bean mesquite, we utilized inductively coupled plasma-optical emission spectroscopy (ICP-OES) and elemental analysis to observe the uptake of copper and the effects on macro and micro nutrients within laboratory-grown seedlings. We have previously shown that pubescens is a hyperaccumulator of copper in soil-grown seedlings. Light and transmission electron microscopy demonstrated death of root cells and ultrastructural changes due to the presence of copper from 50 mg L-1 – 600 mg L-1. Ultrastructural changes included plasmolysis, starch accumulation, increased vacuolation and swollen chloroplasts with disarranged thylakoid membranes in cotyledons. Inductively coupled plasma-optical emission spectroscopy analyses of macro-and micro-nutrients revealed that the presence of copper sulfate in the growth mediium of Petri-dish grown Prosopis pubescens seedlings resulted in dramatic decreases of magnesium, potassium and phosphorus. At 500-600 mg L-1 of copper sulfate a substantial increase of sulfur was present in roots. PMID:24933900

  12. Hijacking membrane transporters for arsenic phytoextraction

    PubMed Central

    LeBlanc, Melissa S.; McKinney, Elizabeth C.; Meagher, Richard B.; Smith, Aaron P.

    2012-01-01

    Arsenic is a toxic metalloid and recognized carcinogen. Arsenate and arsenite are the most common arsenic species available for uptake by plants. As an inorganic phosphate (Pi) analog, arsenate is acquired by plant roots through endogenous Pi transport systems. Inside the cell, arsenate is reduced to the thiol-reactive form arsenite. Glutathione (GSH)-conjugates of arsenite may be extruded from the cell or sequestered in vacuoles by members of the ATP-binding cassette (ABC) family of transporters. In the present study we sought to enhance both plant arsenic uptake through Pi transporter overexpression, and plant arsenic tolerance through ABC transporter overexpression. We demonstrate that Arabidopsis thaliana plants overexpressing the high-affinity Pi transporter family members, AtPht1;1 or AtPht1;7, are hypersensitive to arsenate due to increased arsenate uptake. These plants do not exhibit increased sensitivity to arsenite. Co-overexpression of the yeast ABC transporter YCF1 in combination with AtPht1;1 or AtPht1;7 suppresses the arsenate-sensitive phenotype while further enhancing arsenic uptake. Taken together, our results support an arsenic transport mechanism in which arsenate uptake is increased through Pi transporter overexpression, and arsenic tolerance is enhanced through YCF1-mediated vacuolar sequestration. This work substantiates the viability of coupling enhanced uptake and vacuolar sequestration as a means for developing a prototypical engineered arsenic hyperaccumulator. PMID:23108027

  13. Novel Nickel Resistance Genes from the Rhizosphere Metagenome of Plants Adapted to Acid Mine Drainage▿ †

    PubMed Central

    Mirete, Salvador; de Figueras, Carolina G.; González-Pastor, Jose E.

    2007-01-01

    Metal resistance determinants have traditionally been found in cultivated bacteria. To search for genes involved in nickel resistance, we analyzed the bacterial community of the rhizosphere of Erica andevalensis, an endemic heather which grows at the banks of the Tinto River, a naturally metal-enriched and extremely acidic environment in southwestern Spain. 16S rRNA gene sequence analysis of rhizosphere DNA revealed the presence of members of five phylogenetic groups of Bacteria and the two main groups of Archaea mostly associated with sites impacted by acid mine drainage (AMD). The diversity observed and the presence of heavy metals in the rhizosphere led us to construct and screen five different metagenomic libraries hosted in Escherichia coli for searching novel nickel resistance determinants. A total of 13 positive clones were detected and analyzed. Insights about their possible mechanisms of resistance were obtained from cellular nickel content and sequence similarities. Two clones encoded putative ABC transporter components, and a novel mechanism of metal efflux is suggested. In addition, a nickel hyperaccumulation mechanism is proposed for a clone encoding a serine O-acetyltransferase. Five clones encoded proteins similar to well-characterized proteins but not previously reported to be related to nickel resistance, and the remaining six clones encoded hypothetical or conserved hypothetical proteins of uncertain functions. This is the first report documenting nickel resistance genes recovered from the metagenome of an AMD environment. PMID:17675438

  14. Aquatic arsenic: phytoremediation using floating macrophytes.

    PubMed

    Rahman, M Azizur; Hasegawa, H

    2011-04-01

    Phytoremediation, a plant based green technology, has received increasing attention after the discovery of hyperaccumulating plants which are able to accumulate, translocate, and concentrate high amount of certain toxic elements in their above-ground/harvestable parts. Phytoremediation includes several processes namely, phytoextraction, phytodegradation, rhizofiltration, phytostabilization and phytovolatilization. Both terrestrial and aquatic plants have been tested to remediate contaminated soils and waters, respectively. A number of aquatic plant species have been investigated for the remediation of toxic contaminants such as As, Zn, Cd, Cu, Pb, Cr, Hg, etc. Arsenic, one of the deadly toxic elements, is widely distributed in the aquatic systems as a result of mineral dissolution from volcanic or sedimentary rocks as well as from the dilution of geothermal waters. In addition, the agricultural and industrial effluent discharges are also considered for arsenic contamination in natural waters. Some aquatic plants have been reported to accumulate high level of arsenic from contaminated water. Water hyacinth (Eichhornia crassipes), duckweeds (Lemna gibba, Lemna minor, Spirodela polyrhiza), water spinach (Ipomoea aquatica), water ferns (Azolla caroliniana, Azolla filiculoides, and Azolla pinnata), water cabbage (Pistia stratiotes), hydrilla (Hydrilla verticillata) and watercress (Lepidium sativum) have been studied to investigate their arsenic uptake ability and mechanisms, and to evaluate their potential in phytoremediation technology. It has been suggested that the aquatic macrophytes would be potential for arsenic phytoremediation, and this paper reviews up to date knowledge on arsenic phytoremediation by common aquatic macrophytes.

  15. Evaluation of plant growth regulators to increase nickel phytoextraction by Alyssum species.

    PubMed

    Cabello-Conejo, M I; Centofanti, T; Kidd, P S; Prieto-Fernández, A; Chaney, R L

    2013-01-01

    Recent studies have shown that application of phytohormones to shoots of Alyssum murale increased biomass production but did not increase Ni shoot concentration. Increased biomass and Ni phytoextraction efficiency is useful to achieve economically viable phytomining. The objective of this study was to evaluate the effect of two types of phytohormones on the Ni phytoextraction capacity of four Alyssum species. Two different commercially available phytohormones (Cytokin and Promalin) based on cytokinins and/or gibberellins were applied on shoot biomass of four Ni hyperaccumulating Alyssum species (A. corsicum, A. malacitanum, A. murale, and A. pintodasilvae). Cytokin was applied in two concentrations and promalin in one concentration. The application of phytohormones had no clear positive effect on biomass production, Ni accumulation and Ni phytoextraction efficiency in the studied Alyssum species. A. malacitanum was the only species in which a significantly negative effect of these treatments was observed (in Ni uptake). A slightly positive response to promalin treatment was observed in the biomass production and Ni phytoextraction efficiency of A. corsicum. Although this effect was not significant it does indicate a potential application of these approaches to improve phytoextraction ability. Further studies will be needed to identify the most adequate phytohormone treatment as well as the appropriate concentrations and application times.

  16. [Research advances in uptake, translocation, accumulation and detoxification of Pb in plants].

    PubMed

    Duan, De-Chao; Yu, Ming-Ge; Shi, Ji-Yan

    2014-01-01

    Contamination of soils by lead (Pb) is of widespread occurrence because of the industrialization, urbanization, mining, and many other anthropogenic activities. It is urgent and necessary for scientists to uncover the mechanisms of uptake, translocation, accumulation and detoxification of Pb in plants for the following two reasons. First, it helps target and regulate the key process of Pb uptake by crops and vegetables and minimize the threat of Pb introduction to the food chain. Second, it helps cultivate Pb hyperaccumulating plants that can absorb and sequester excessive amounts from contaminated soils in their biomass without incurring damage to basic metabolic functions. The purpose of this review was to summarize the research advances in uptake, translocation and accumulation of Pb in plants and address the mechanisms by which plants or plant systems detoxify Pb. The further researches on the foliar uptake, the interactions between soil components and plant cell wall, as well as the integrated technologies for phytoremediation of Pb-contaminated soils were prospected.

  17. Progress Toward Clonable Inorganic Nanoparticles

    PubMed Central

    Ni, Thomas W.; Staicu, Lucian C.; Nemeth, Richard S.; Schwartz, Cindi; Crawford, David; Seligman, Jeffrey D.; Hunter, William J.; Pilon-Smits, Elizabeth; Ackerson, Christopher J.

    2015-01-01

    Pseudomonas moraviensis stanleyae was recently isolated from the roots of the Selenium (Se) hyperaccumulator plant Stanleya pinnata. This bacterium tolerates normally lethal concentrations of SeO32− in liquid culture, where it also produces Se nanoparticles. Structure and cellular ultrastructure of the Se nanoparticles as determined by cellular electron tomography shows the nanoparticles as intracellular, of narrow dispersity, symmetrically irregular and without any observable membrane or structured protein shell. Protein mass spectrometry of a fractionated soluble cytosolic material with selenite reducing capability identified nitrite reductase and glutathione reductase homologues as NADPH dependent candidate enzymes for the reduction of selenite to zerovalent Se nanoparticles. In vitro experiments with commercially sourced glutathione reductase revealed that the enzyme can reduce SeO32− (selenite) to Se nanoparticles in an NADPH-dependent process. The disappearance of the enzyme as determined by protein assay during nanoparticle formation suggests that glutathione reductase is associated with or possibly entombed in the nanoparticles whose formation it catalyzes. Chemically dissolving the nanoparticles releases the enzyme. The size of the nanoparticles varies with SeO32− concentration, varying in size form 5nm diameter when formed at 1.0 μM [SeO32−] to 50nm maximum diameter when formed at 100 μM [SeO32−]. In aggregate, we suggest that glutathione reductase possesses the key attributes of a clonable nanoparticle system: ion reduction, nanoparticle retention and size control of the nanoparticle at the enzyme site. PMID:26350616

  18. Increasing the Richness of Culturable Arsenic-Tolerant Bacteria from Theonella swinhoei by Addition of Sponge Skeleton to the Growth Medium.

    PubMed

    Keren, Ray; Lavy, Adi; Ilan, Micha

    2016-05-01

    Theonella swinhoei is an arsenic hyper-accumulator sponge, harboring a multitude of associated bacteria. These bacteria reside in the mesohyl, the dense extracellular matrix of the sponge. Previous elemental analysis of separated cell fractions from the sponge had determined that arsenic is localized to the associated bacteria. Subsequently, sponge-associated arsenic-tolerant bacteria were isolated here and grouped into 15 operational taxonomic units (OTUs, 97% similarity). Both culture-dependent and culture-independent work had revealed that T. swinhoei harbors a highly diverse bacterial community. It was thus hypothesized the acclimation of bacteria in the presence of a sponge skeleton, better mimicking its natural environment, would increase the yield of isolation of sponge-associated bacteria. Using seven modularly designed media, 380 bacteria isolates were grown and grouped into 22 OTUs. Inclusion of sponge skeleton in the growth medium promoted bacterial growth in all seven media, accounting for 20 of the 22 identified OTUs (the other two in a medium without skeleton). Diversity and richness indices were calculated for each treatment or combination of treatments with shared growth parameters. Integrating data inherent in the modularly designed media with the ecological indices led to the formation of new hypotheses regarding the aeration conditions and expected arsenic form in situ. Both aerobic and anoxic conditions are expected to occur in the sponge (temporally and/or spatially). Arsenate is expected to be the dominant (or even the only) arsenic form in the sponge.

  19. Investigation of biomethylation of arsenic and tellurium during composting.

    PubMed

    Diaz-Bone, Roland A; Raabe, Maren; Awissus, Simone; Keuter, Bianca; Menzel, Bernd; Küppers, Klaus; Widmann, Renatus; Hirner, Alfred V

    2011-05-30

    Though the process of composting features a high microbiological activity, its potential to methylate metals and metalloids has been little investigated so far in spite of the high impact of this process on metal(loid) toxicity and mobility. Here, we studied the biotransformation of arsenic, tellurium, antimony, tin and germanium during composting. Time resolved investigation revealed a highly dynamic process during self-heated composting with markedly differing time patterns for arsenic and tellurium species. Extraordinary high concentrations of up to 150 mg kg(-1) methylated arsenic species as well as conversion rates up to 50% for arsenic and 5% for tellurium were observed. In contrast, little to no conversion was observed for antimony, tin and germanium. In addition to experiments with metal(loid) salts, composting of arsenic hyperaccumulating ferns Pteris vittata and P. cretica grown on As-amended soils was studied. Arsenic accumulated in the fronds was efficiently methylated resulting in up to 8 mg kg(-1) methylated arsenic species. Overall, these studies indicate that metal(loid)s can undergo intensive biomethylation during composting. Due to the high mobility of methylated species this process needs to be considered in organic waste treatment of metal(loid) contaminated waste materials.

  20. Remediation of metalliferous mines, revegetation challenges and emerging prospects in semi-arid and arid conditions.

    PubMed

    Nirola, Ramkrishna; Megharaj, Mallavarapu; Beecham, Simon; Aryal, Rupak; Thavamani, Palanisami; Vankateswarlu, Kadiyala; Saint, Christopher

    2016-10-01

    Understanding plant behaviour in polluted soils is critical for the sustainable remediation of metal-polluted sites including abandoned mines. Post-operational and abandoned metal mines particularly in semi-arid and arid zones are one of the major sources of pollution by soil erosion or plant hyperaccumulation bringing ecological impacts. We have selected from the literature 157 species belonging to 50 families to present a global overview of 'plants under action' against heavy metal pollution. Generally, all species of plants that are drought, salt and metal tolerant are candidates of interest to deal with harsh environmental conditions, particularly at semi-arid and arid mine sites. Pioneer metallophytes namely Atriplex nummularia, Atriplex semibaccata, Salsola kali, Phragmites australis and Medicago sativa, representing the taxonomic orders Caryophyllales, Poales and Fabales are evaluated in terms of phytoremediation in this review. Phytoremediation processes, microbial and algal bioremediation, the use and implication of tissue culture and biotechnology are critically examined. Overall, an integration of available remediation plant-based technologies, referred to here as 'integrated remediation technology,' is proposed to be one of the possible ways ahead to effectively address problems of toxic heavy metal pollution. Graphical abstract Integrated remediation technology (IRT) in metal-contaminated semi-arid and arid conditions. The hexagonal red line represents an IRT concept based on remediation decisions by combination of plants and microbial processes.

  1. [Application potential of siderophore-producing rhizobacteria in phytoremediation of heavy metals-contaminated soils: a review].

    PubMed

    Wang, Ying-Li; Lin, Qing-Qi; Li, Yu; Yang, Xiu-Hong; Wang, Shi-Zhong; Qiu, Rong-Liang

    2013-07-01

    Siderophore-producing rhizobacteria (SPR) are a group of plant growth-promoting rhizobacteria, being able to play an important role in assisting the phytoremediation of heavy metals-contaminated soils. Based on the comprehensive analysis of related researches at home and abroad, this paper elaborated the functions of SPR in alleviating the heavy metals stress and toxicity to plants and the mechanisms of SPR in improving the heavy metals bioavailability in soil, and indicated that SPR had good application potential in promoting the plant growth in heavy metals-contaminated soils and reinforcing the heavy metals accumulation in plants. The contradictory phenomena of SPR in increasing or decreasing heavy metals accumulation in plants, which existed in current researches, were also analyzed. Aiming at the deficiencies in current researches, it was suggested that in the future researches, the mechanisms of the interactions between SPR and plants, especially hyperaccumulators, should be further studied, the key factors affecting the heavy metals complexation and mobilization in soil by siderophores should also be further clarified, the effects of siderophores on the heavy metals bioavailability and its subsequent influence on the heavy metals uptake by plants should be comprehensively considered, and the measures for improving the colonization of SPR in heavy metals-contaminated soil should be explored.

  2. Phytoaccumulation of Heavy Metals in Natural Vegetation at the Municipal Wastewater Site in Abbottabad, Pakistan.

    PubMed

    Irshad, Muhammad; Ruqia, Bibi; Hussain, Zahid

    2015-01-01

    Heavy metal accumulation in crops and soils from wastewater irrigation poses a significant threat to the human health. A study was carried out to investigate the removal potential of heavy metals (HM) by native plant species, namely Cannabis sativa L., Chenopodium album L., Datura stramonium L., Sonchus asper L., Amaranthus viridus L., Oenothera rosea (LHer), Xanthium stramonium L., Polygonum macalosa L., Nasturtium officinale L. and Conyza canadensis L. growing at the municipal wastewater site in Abbottabad city, Pakistan. The HM concentrations varied among plants depending on the species. Metal concentrations across species varied in the order iron (Fe) > zinc (Zn) > chromium (Cr) > nickel (Ni) > cadmium (Cd). Majority of the species accumulated more HM in roots than shoots. Among species, the concentrations (both in roots and shoots) were in the order C. sativa > C. album > X. stramonium > C. canadensis > A. viridus > N. officinale > P. macalosa > D. stramonium > S. asper > O. rosea. No species was identified as a hyperaccumulator. All species exhibited a translocation factor (TF) less than 1. Species like C. sativa, C. album and X. stramonium gave higher (> 1) biological concentration factor (BCF) and biological accumulation coefficient (BAC) especially for Fe, Cr and Cd than other species. Higher accumulation of heavy metals in these plant species signifies the general application of these species for phytostabilization and phytoextraction of HM from polluted soils.

  3. Assessment of native plant species for phytoremediation of heavy metals growing in the vicinity of NTPC sites, Kahalgaon, India.

    PubMed

    Kumari, Alka; Lal, Brij; Rai, Upendra Nath

    2016-01-01

    The present investigation was carried out to screen native plants growing in fly ash (FA) contaminated areas near National Thermal Power Corporation (NTPC), Kahalgaon, Bihar, India with a view to using them for the eco-restoration of the area. A total number of 30 plant species (5 aquatic and 25 terrestrial including 6 ferns) were collected and their diversity status and dominance were also studied. After screening of dominant species at highly polluted site, 8 terrestrial and 5 aquatic plants were analyzed for heavy metals (Fe, Zn, Cu, Ni, Si, Al, Pb, Cr, and Cd). Differential accumulations of various heavy metals by different species of plants were observed. Typha latifolia was found to be most efficient metal accumulator of Fe (927), Cu (58), Zn (87), Ni (57), Al (67), Cd (95), and Pb (69), and Azolla pinnata as Cr (93) hyper-accumulator among aquatic species in µg g(-1). In terrestrial species the maximum levels of Fe (998), Zn (81), Ni (93), Al (121), and Si (156) were found in Croton bonplandium. However, there was high spatial variability in total metal accumulation in different species indicated by coefficient of variation (CV%). These results suggest that various aquatic, some dominant terrestrial plants including fern species may be used in a synergistic way to remediate and restore the FA contaminated wastelands.

  4. Enhancement of heavy metal phytoremediation by Alnus firma with endophytic Bacillus thuringiensis GDB-1.

    PubMed

    Babu, A Giridhar; Kim, Jong-Dae; Oh, Byung-Taek

    2013-04-15

    Phytoremediation shows potential for remediating mine tailing sites contaminated with heavy metals. Our aim was to isolate, characterize, and assess the potential of endophytic bacteria to enhance growth and metal accumulation by the hyperaccumulator Alnus firma. A bacterial strain isolated from roots of Pinus sylvestris had the capacity to remove heavy metals from mine tailing and was identified as Bacillus thuringiensis GDB-1 based on 16S ribosomal DNA sequencing. GDB-1 exhibited plant growth-promoting traits, including 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, indole acetic acid (IAA) and siderophore production, and P solubilization. The efficiency of GDB-1 to remove heavy metals was influenced by pH and initial metal concentration. Removal capacity (mg/l) was 77% for Pb (100), 64% for Zn (50), 34% for As (50), 9% for Cd (10), 8% for Cu (10), and 8% for Ni (10) during the active growth cycle in heavy metal-amended, mine tailing extract medium. Inoculating soil with GDB-1 significantly increased biomass, chlorophyll content, nodule number, and heavy metal (As, Cu, Pb, Ni, and Zn) accumulation in A. firma seedlings. Results indicate that inoculating the native plant A. firma with B. thuringiensis GDB-1 improves its efficiency for phytoremediation of soil containing mine tailings contaminated with heavy metals.

  5. Micro-PIXE analyses of frozen-hydrated semi-thick biological sections

    NASA Astrophysics Data System (ADS)

    Wang, Y. D.; Mesjasz-Przybylowicz, J.; Tylko, G.; Barnabas, A. D.; Przybylowicz, W. J.

    2013-07-01

    Cryo-micro-PIXE system and methodology of microanalysis of frozen-hydrated semi-thick biological sections is described. A commercially available cryotransfer system used in electron microscopy has been adapted for this purpose. The analyzed material was frozen by metal-mirror method and sections of 20-50 micron thickness were prepared. Micro-PIXE and simultaneous proton backscattering was performed using 3 MeV proton beam. Monitoring of water vapour composition during the proton bombardment showed good stability of the analyzed material. The results of repetitive analyses of standards prepared from gelatin-glycerol solution with added known concentrations of K, Ni, Cu, Zn were in good agreement with expected, calculated values. Mass losses and changes of elemental composition were monitored. Elemental maps obtained for frozen-hydrated semi-thick section of Ni hyperaccumulator Senecio coronatus showed excellent preservation of leaf morphology and the distribution of elements. Quantitative elemental mapping of frozen-hydrated specimens compared with subsequent analysis of the same areas after freeze-drying revealed similar distribution pattern in both cases. It is clear, however, that freeze-drying induces some distortion of cell morphology and specimen shrinkage.

  6. Phytotoxicity of wastewater containing lead (Pb) effects Scirpus grossus.

    PubMed

    Tangahu, B Voijant; Abdullah, S Rozaimah Sheikh; Basri, H; Idris, M; Anuar, N; Mukhlisin, M

    2013-01-01

    Phytoremediation is an environment-friendly and cost-effective method to clean the environment of heavy metal contamination. A prolonged phytotoxicity test was conducted in a single exposure. Scirpus grossus plants were grown in sand to which the diluted Pb (NO3)2 was added, with the variation of concentration were 0, 100, 200, 400, 600, and 800 mg/L. It was found that Scirpus grossus plants can tolerate Pb at concentrations of up to 400 mg/L. The withering was observed on day-7 for Pb concentrations of 400 mg/L and above. 100% of the plants withered with a Pb concentration of 600 mg/L on day 65. The Pb concentration in water medium decreased while in plant tissues increased. Adsorption of Pb solution ranged between 2 to 6% for concentrations of 100 to 800 mg/L. The Bioaccumulation Coefficient and Translocation Factor of Scirpus grossus were found greater than 1, indicating that this species is a hyperaccumulator plant.

  7. Accumulation of Pb, Cu, and Zn in native plants growing on contaminated sites and their potential accumulation capacity in Heqing, Yunnan.

    PubMed

    Liu, Xiaohai; Gao, Yuntao; Khan, Sardar; Duan, Gang; Chen, Aikui; Ling, Li; Zhao, Leil; Liu, Zhonghan; Wu, Xuecan

    2008-01-01

    Phytoremediation is one of the cost-effective and environmental friendly technologies used to remove contaminants from contaminated soils, which has been intensively studied during the last decade. Presently, few economical and effective remediation methods are available for the remediation of Pb contaminated sites. This study was conducted to assess the potential of 19 plants growing on contaminated sites in Pb mine area. Plants and associated soil samples were collected and analyzed for total metal concentrations. While total soil Pb, Cu and Zn concentrations varied from 1,239 to 4,311, 36 to 1,020 and 240 to 2,380 mg/kg, those in the plant shoots ranged from 6.3 to 2,029, 20 to 570, and 36 to 690 mg/kg, respectively. Among the plants, we found that one cultivated crop (Ricinus communis L.) and two native species (Tephrosia candida and Debregeasia orientalis) have a great potential for phytoremediation of Pb contaminated soils, the Pb hyperaccumulation capacity of the 3 plants was found as the order: R. communis > D. orientalis > T. candida in the investigated area.

  8. Effect of arsenic absorption on the water-refilling speed of Pteris cretica.

    PubMed

    Lee, Sang Joon; Lee, Jin Pyung

    2011-06-01

    Heavy metals are largely responsible for soil and water pollution. Recently, phytoremediation is receiving a large attention as a plant-based technology for removing metals from contaminated soil and water in an environment-friendly and cost-effective way. In such context, some species of ferns such as Pteris cretica were found to be a hyper-accumulator of arsenic (As). In this study, we first explored the validity of measuring the water-refilling process in xylem vessels of Pteris cretica using the synchrotron X-ray microimaging technique. Then we investigated the effects of arsenic concentration on the water-refilling speed inside the xylem vessel. The methodology to measure the water-refilling speed was consistent within five repetitions and 3 hours after the stem sample was cut from the plant. The water-refilling speed in the xylem vessels of the Pteris grown in arsenic solution was faster than that in normal water. Arsenic concentration of 0-1,000 μM was tested and the maximum speed was obtained at 500 μM. Conclusively, the experimental methodology developed in this study allowed to obtain some interesting results for understanding how arsenic affect the xylem sap flow transport and the mechanism by which growth is enhanced in the presence of heavy metal.

  9. Risk Assessment of Fluoride Intake from Tea in the Republic of Ireland and its Implications for Public Health and Water Fluoridation.

    PubMed

    Waugh, Declan T; Potter, William; Limeback, Hardy; Godfrey, Michael

    2016-02-26

    The Republic of Ireland (RoI) is the only European Country with a mandatory national legislation requiring artificial fluoridation of drinking water and has the highest per capita consumption of black tea in the world. Tea is a hyperaccumulator of fluoride and chronic fluoride intake is associated with multiple negative health outcomes. In this study, fifty four brands of the commercially available black tea bag products were purchased and the fluoride level in tea infusions tested by an ion-selective electrode method. The fluoride content in all brands tested ranged from 1.6 to 6.1 mg/L, with a mean value of 3.3 mg/L. According to our risk assessment it is evident that the general population in the RoI is at a high risk of chronic fluoride exposure and associated adverse health effects based on established reference values. We conclude that the culture of habitual tea drinking in the RoI indicates that the total cumulative dietary fluoride intake in the general population could readily exceed the levels known to cause chronic fluoride intoxication. Evidence suggests that excessive fluoride intake may be contributing to a wide range of adverse health effects. Therefore from a public health perspective, it would seem prudent and sensible that risk reduction measures be implemented to reduce the total body burden of fluoride in the population.

  10. Accumulation of radium in relation to some chemical analogues in Dicranopteris linearis.

    PubMed

    Chao, J H; Chuang, C Y

    2011-01-01

    This study elucidates the uptake and accumulation of radium in the field-growing fern Dicranopteris linearis by relating the radium concentration to some potential chemical analogues, including alkaline earth metals, rare earth elements, and some important heavy metals. Time-dependent accumulation of radium and these chemical analogues for D. linearis were described by the (228)Th/(228)Ra activity ratio, an index for inferring plant age. The correlation between radium and these elements was assessed by statistical analysis and used as a reference to elucidate the uptake and accumulation of radium in relation to the chemical analogues. Analytical and statistical results showed that the concentrations of alkaline earth metals (except for Mg) rare earth elements and some heavy metals in D. linearis increased linearly with plant age. These elements, exhibiting a similar accumulation pattern to radium and significant correlation coefficients with radium, were considered as the chemical analogues to radium. Additionally, the plant/soil concentration ratios (CRs) for radium and most of these analogues in D. linearis exceeded 1, consistent with the definition of hyper-accumulator plants.

  11. Tryptophan-Derived Metabolites Are Required for Antifungal Defense in the Arabidopsis mlo2 Mutant1[C][W][OA

    PubMed Central

    Consonni, Chiara; Bednarek, Paweł; Humphry, Matt; Francocci, Fedra; Ferrari, Simone; Harzen, Anne; Ver Loren van Themaat, Emiel; Panstruga, Ralph

    2010-01-01

    Arabidopsis (Arabidopsis thaliana) genes MILDEW RESISTANCE LOCUS O2 (MLO2), MLO6, and MLO12 exhibit unequal genetic redundancy with respect to the modulation of defense responses against powdery mildew fungi and the control of developmental phenotypes such as premature leaf decay. We show that early chlorosis and necrosis of rosette leaves in mlo2 mlo6 mlo12 mutants reflects an authentic but untimely leaf senescence program. Comparative transcriptional profiling revealed that transcripts of several genes encoding tryptophan biosynthetic and metabolic enzymes hyperaccumulate during vegetative development in the mlo2 mlo6 mlo12 mutant. Elevated expression levels of these genes correlate with altered steady-state levels of several indolic metabolites, including the phytoalexin camalexin and indolic glucosinolates, during development in the mlo2 single mutant and the mlo2 mlo6 mlo12 triple mutant. Results of genetic epistasis analysis suggest a decisive role for indolic metabolites in mlo2-conditioned antifungal defense against both biotrophic powdery mildews and a camalexin-sensitive strain of the necrotrophic fungus Botrytis cinerea. The wound- and pathogen-responsive callose synthase POWDERY MILDEW RESISTANCE4/GLUCAN SYNTHASE-LIKE5 was found to be responsible for the spontaneous callose deposits in mlo2 mutant plants but dispensable for mlo2-conditioned penetration resistance. Our data strengthen the notion that powdery mildew resistance of mlo2 genotypes is based on the same defense execution machinery as innate antifungal immune responses that restrict the invasion of nonadapted fungal pathogens. PMID:20023151

  12. Direct Measurement of 59Fe-Labeled Fe2+ Influx in Roots of Pea Using a Chelator Buffer System to Control Free Fe2+ in Solution.

    PubMed Central

    Fox, T. C.; Shaff, J. E.; Grusak, M. A.; Norvell, W. A.; Chen, Y.; Chaney, R. L.; Kochian, L. V.

    1996-01-01

    Fe2+ transport in plants has been difficult to quantify because of the inability to control Fe2+ activity in aerated solutions and non-specific binding of Fe to cell walls. In this study, a Fe(II)-3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-4[prime]4"-disulfonic acid buffer system was used to control free Fe2+ in uptake solutions. Additionally, desorption methodologies were developed to adequately remove nonspecifically bound Fe from the root apoplasm. This enabled us to quantify unidirectional Fe2+ influx via radiotracer (59Fe) uptake in roots of pea (Pisum sativum cv Sparkle) and its single gene mutant brz, an Fe hyperaccumulator. Fe influx into roots was dramatically inhibited by low temperature, indicating that the measured Fe accumulation in these roots was due to true influx across the plasma membrane rather than nonspecific binding to the root apoplasm. Both Fe2+ influx and Fe translocation to the shoots were stimulated by Fe deficiency in Sparkle. Additionally, brz, a mutant that constitutively exhibits high ferric reductase activity, exhibited higher Fe2+ influx rates than +Fe-grown Sparkle. These results suggest that either Fe deficiency triggers the induction of the Fe2+ transporter or that the enhanced ferric reductase activity somehow stimulates the activity of the existing Fe2+ transport protein. PMID:12226276

  13. Accumulation of arsenic, lead, copper, and zinc, and synthesis of phytochelatins by indigenous plants of a mining impacted area.

    PubMed

    Machado-Estrada, Blenda; Calderón, Jaqueline; Moreno-Sánchez, Rafael; Rodríguez-Zavala, José S

    2013-06-01

    Several native plants, able to grow in an unconfined mining impacted area that is now in close vicinity with urban areas, were evaluated for their ability to accumulate heavy metals. The main soil contaminants were As, Pb, Cu, and Zn. Sampling of the rhizospheric metal polluted soil showed that Euphorbia prostrata Aiton, Parthenium incanum Kunth, and Zinnia acerosa (DC.) A. Gray were able to grow in the presence of high amounts of mixtures of these elements. The plants accumulated the metals in the above ground parts and increased the synthesis of thiol molecules. E. prostrata showed the highest capacity for accumulation of the mixture of elements (588 μg g DW(-1)). Analysis of the thiol-molecules profile showed that these plants synthesized high amounts of long-chain phytochelatins, accompanied by low amounts of monothiol molecules, which may be related to their higher resistance to As and heavy metals. The three plants showed translocation factors from roots to leaves >1 for As, Pb, Cu, and Zn. Thus, by periodically removing aerial parts, these plants could be useful for the phytoremediation of semi-arid and arid mining impacted areas, in which metal hyper-accumulator plants are not able to grow.

  14. Tissue-Specific Apocarotenoid Glycosylation Contributes to Carotenoid Homeostasis in Arabidopsis Leaves1

    PubMed Central

    Hübner, Michaela; Matsubara, Shizue; Beyer, Peter

    2015-01-01

    Attaining defined steady-state carotenoid levels requires balancing of the rates governing their synthesis and metabolism. Phytoene formation mediated by phytoene synthase (PSY) is rate limiting in the biosynthesis of carotenoids, whereas carotenoid catabolism involves a multitude of nonenzymatic and enzymatic processes. We investigated carotenoid and apocarotenoid formation in Arabidopsis (Arabidopsis thaliana) in response to enhanced pathway flux upon PSY overexpression. This resulted in a dramatic accumulation of mainly β-carotene in roots and nongreen calli, whereas carotenoids remained unchanged in leaves. We show that, in chloroplasts, surplus PSY was partially soluble, localized in the stroma and, therefore, inactive, whereas the membrane-bound portion mediated a doubling of phytoene synthesis rates. Increased pathway flux was not compensated by enhanced generation of long-chain apocarotenals but resulted in higher levels of C13 apocarotenoid glycosides (AGs). Using mutant lines deficient in carotenoid cleavage dioxygenases (CCDs), we identified CCD4 as being mainly responsible for the majority of AGs formed. Moreover, changed AG patterns in the carotene hydroxylase mutants lutein deficient1 (lut1) and lut5 exhibiting altered leaf carotenoids allowed us to define specific xanthophyll species as precursors for the apocarotenoid aglycons detected. In contrast to leaves, carotenoid hyperaccumulating roots contained higher levels of β-carotene-derived apocarotenals, whereas AGs were absent. These contrasting responses are associated with tissue-specific capacities to synthesize xanthophylls, which thus determine the modes of carotenoid accumulation and apocarotenoid formation. PMID:26134165

  15. Assessment and control of the bioavailability of nickel in soils.

    PubMed

    Echevarria, Guillaume; Massoura, Stamatia Tina; Sterckeman, Thibault; Becquer, Thierry; Schwartz, Christophe; Morel, Jean Louis

    2006-03-01

    Nickel, a potentially toxic metal, is present in all soils with an average concentration of 20 to 30 mg/kg, sometimes exceeding 10,000 mg/kg (e.g., ultramafic soils). The ecotoxicological risk of Ni in soils to organisms is controlled by its availability. It is therefore essential to identify an efficient and reliable method for the evaluation of this risk. This paper presents a complete study of the effect of Ni origin, localization, and soil properties on its availability as assessed with the isotopic exchange kinetics (IEK) method and compares plant response to isotopically exchangeable properties of Ni in soils. We performed IEK on 100 soil samples representing a worldwide range of Ni fate, and concentrations showed that pH was the main influencing parameter and that labile Ni (i.e., isotopically exchangeable Ni, Et) could be reasonably well assessed by a single diethylene triamine pentaacetic acid extraction. The identification of the soil mineral phases that bear Ni (bearing phases) in 16 Ni-rich samples selected among the 100 soils showed a strong effect of the mineralogy of the bearing phases on Ni availability (IEK). Plants with different Ni accumulation strategies all took up Ni from the same labile pool of Ni in four contrasting soils, and the amount taken up by hyperaccumulator plants could be anticipated with the IEK parameters, thus confirming the usefulness of isotopic dilution methods for risk assessment.

  16. Tie-dyed2 encodes a callose synthase that functions in vein development and affects symplastic trafficking within the phloem of maize leaves.

    PubMed

    Slewinski, Thomas L; Baker, R Frank; Stubert, Adam; Braun, David M

    2012-11-01

    The tie-dyed2 (tdy2) mutant of maize (Zea mays) displays variegated green and yellow leaves. Intriguingly, the yellow leaf tissues hyperaccumulate starch and sucrose, the soluble sugar transported long distance through the phloem of veins. To determine the molecular basis for Tdy2 function, we cloned the gene and found that Tdy2 encodes a callose synthase. RNA in situ hybridizations revealed that in developing leaves, Tdy2 was most highly expressed in the vascular tissue. Comparative expression analysis with the vascular marker maize PINFORMED1a-yellow fluorescent protein confirmed that Tdy2 was expressed in developing vein tissues. To ascertain whether the defect in tdy2 leaves affected the movement of sucrose into the phloem or its long-distance transport, we performed radiolabeled and fluorescent dye tracer assays. The results showed that tdy2 yellow leaf regions were defective in phloem export but competent in long-distance transport. Furthermore, transmission electron microscopy of tdy2 yellow leaf regions showed incomplete vascular differentiation and implicated a defect in cell-to-cell solute movement between phloem companion cells and sieve elements. The disruption of sucrose movement in the phloem in tdy2 mutants provides evidence that the Tdy2 callose synthase functions in vascular maturation and that the vascular defects result in impaired symplastic trafficking into the phloem translocation stream.

  17. Compromised virus-induced gene silencing in RDR6-deficient plants.

    PubMed

    Vaistij, Fabián E; Jones, Louise

    2009-03-01

    RNA silencing in plants serves as a potent antiviral defense mechanism through the action of small interfering RNAs (siRNAs), which direct RNA degradation. siRNAs can be derived directly from the viral genome or via the action of host-encoded RNA-dependent RNA polymerases (RDRs). Plant genomes encode multiple RDRs, and it has been demonstrated that plants defective for RDR6 hyperaccumulate several classes of virus. In this study, we compared the effectiveness of virus-induced gene silencing (VIGS) and RNA-directed DNA methylation (RdDM) in wild-type and RDR6-deficient Nicotiana benthamiana plants. For the potexvirus Potato virus X (PVX) and the potyvirus Plum pox virus (PPV), the efficiency of both VIGS and RdDM were compromised in RDR6-defective plants despite accumulating high levels of viral siRNAs similar to infection of wild-type plants. The reduced efficiency of VIGS and RdDM was unrelated to the size class of siRNA produced and, at least for PVX, was not dependent on the presence of the virus-encoded silencing suppressor protein, 25K. We suggest that primary siRNAs produced from PVX and PPV in the absence of RDR6 may not be good effectors of silencing and that RDR6 is required to produce secondary siRNAs that drive a more effective antiviral response.

  18. Chemical-assisted phytoremediation of CD-PAHs contaminated soils using Solanum nigrum L.

    PubMed

    Yang, Chuanjie; Zhou, Qixing; Wei, Shuhe; Hu, Yahu; Bao, Yanyu

    2011-09-01

    A well-characterized cadmium (Cd) hyperaccumulating plant Solanum nigrum was grown in Cd and polycyclic aromatic hydrocarbons (PAHs) co-contaminated soil that was repeatedly amended with chemicals, including EDTA, cysteine (CY), salicylic acid (Sa), and Tween 80 (TW80), to test individual and combined treatment effects on phytoremediation of Cd-PAHs contaminated soils. Plant growth was negatively affected by exogenous chemicals except for EDTA. S. nigrum could accumulate Cd in tissues without assistant chemicals, while there was no visible effect on the degradation of PAHs. Cysteine had significant effects on phytoextraction of Cd and the highest metal extraction ratio (1.27%) was observed in 0.9 mmol/kg CY treatment. Both salicylic acid and Tween 80 had stimulative effects on the degradation of PAHs and there was the maximal degradation rate (52.6%) of total PAHs while 0.9 mmol/kg Sa was applied. Furthermore, the combined treatment T(0.1EDTA+0.9CY+0.5TW80) and T(0.5EDTA+0.9CY+03Sa) could not only increase the accumulation of Cd in plant tissues, but also promote the degradation of PAHs. These results indicated that S. nigrum might be effective in phytoextracting Cd and enhancing the biodegradation of PAHs in the co-contaminated soils with assistant chemicals.

  19. Studying the enhanced phytoremediation of lead contaminated soils via laser induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Hassan, M.; Sighicelli, M.; Lai, A.; Colao, F.; Ahmed, A. H. Hanafy; Fantoni, R.; Harith, M. A.

    2008-10-01

    Phytoremediation popularly known as 'green clean technology' is a new promising technology used for toxic contaminants removal from the environment such as heavy metals (HMs), adopting suitable plants. This concept is increasingly being adopted as it is a cost effective and environmentally friendly alternative to traditional methods of treatment. This study was focused on using scented geranium, Pelargonium zonale, as accumulator or hyperaccumulator plant for natural lead extraction from artificially contaminated soil with different Pb concentrations (0, 2000, 5000, 7000 ppm). Utilization of EDTA as a chelator, that would permit higher metal availability and uptake by the tested plants roots, was also tested. Laser Induced Breakdown Spectroscopy (LIBS) was used to follow up Pb concentrations in both soil and plant green harvestable parts known as shoots, before, during and after lead addition in soil. LIBS measurements were conducted in a microdestructive way by focusing a high energy Nd:YAG laser, emitting at 1064 nm, on plant and soil samples previously dried, homogenized and pressed in pellets. The emitted LIBS spectra were acquired by a gated CCD after dispersion on a monochromator and analyzed to retrieve relative concentrations of the selected HM both in the soil and on plants as a function of the time after doping and eventual chelator addition. EDTA was found to enhance Pb uptake from the soil which increased with time, good correlation was found between LIBS and ICP-OES results of plant tissues spectrochemical analysis.

  20. Purification and characterization of a highly active chromate reductase from endophytic Bacillus sp. DGV19 of Albizzia lebbeck (L.) Benth. actively involved in phytoremediation of tannery effluent-contaminated sites.

    PubMed

    Manikandan, Muthu; Gopal, Judy; Kumaran, Rangarajulu Senthil; Kannan, Vijayaraghavan; Chun, Sechul

    2016-01-01

    Phytoremediation using timber-yielding tree species is considered to be the most efficient method for chromium/tannery effluent-contaminated sites. In this study, we have chosen Albizzia lebbeck, a chromium hyperaccumulator plant, and studied one of its chromium detoxification processes operated by its endophytic bacterial assemblage. Out of the four different groups of endophytic bacteria comprising Pseudomonas, Rhizobium, Bacillus, and Salinicoccus identified from A. lebbeck employed in phytoremediation of tannery effluent-contaminated soil, Bacillus predominated with three species, which exhibited not only remarkable chromium accumulation ability but also high chromium reductase activity. A chromate reductase was purified to homogeneity from the most efficient chromium accumulator, Bacillus sp. DGV 019, and the purified 34.2-kD enzyme was observed to be stable at temperatures from 20°C to 60°C. The enzyme was active over a wide range of pH values (4.0-9.0). Furthermore, the enzyme activity was enhanced with the electron donors NADH, followed by NADPH, not affected by glutathione and ascorbic acid. Cu(2+) enhanced the activity of the purified enzyme but was inhibited by Zn(2+) and etheylenediamine tetraacetic acid (EDTA). In conclusion, due to its versatile adaptability the chromate reductase can be used for chromium remediation.

  1. Pongamia pinnata inoculated with Bradyrhizobium liaoningense PZHK1 shows potential for phytoremediation of mine tailings.

    PubMed

    Yu, Xiumei; Li, Yangxin; Li, Yanmei; Xu, Chaohua; Cui, Yongliang; Xiang, Quanju; Gu, Yunfu; Zhao, Ke; Zhang, Xiaoping; Penttinen, Petri; Chen, Qiang

    2017-02-01

    Mine tailings contain high concentrations of metal contaminants and only little nutrients, making the tailings barren for decades after the mining has been terminated. Effective phytoremediation of mine tailings calls for deep-rooted, metal accumulating, and soil fertility increasing plants with tolerance against harsh environmental conditions. We assessed the potential of the biofuel leguminous tree Pongamia pinnata inoculated with plant growth promoting rhizobia to remediate iron-vanadium-titanium oxide (V-Ti magnetite) mine tailing soil by pot experiment and in situ remediation test. A metal tolerant rhizobia strain PZHK1 was isolated from the tailing soil and identified as Bradyrhizobium liaoningense by phylogenetic analysis. Inoculation with PZHK1 increased the growth of P. pinnata both in V-Ti magnetite mine tailings and in Ni-contaminated soil. Furthermore, inoculation increased the metal accumulation capacity and superoxide dismutase activity of P. pinnata. The concentrations of Ni accumulated by inoculated plants were higher than the hyperaccumulator threshold. Inoculated P. pinnata accumulated high concentration of Fe, far exceeding the upper limit (1000 mg kg(-1)) of Fe in plant tissue. In summary, P. pinnata-B. liaoningense PZHK1 symbiosis showed potential to be applied as an effective phytoremediation technology for mine tailings and to produce biofuel feedstock on the marginal land.

  2. The contribution of endophytic bacteria to Albizia lebbeck-mediated phytoremediation of tannery effluent contaminated soil.

    PubMed

    Manikandan, Muthu; Kannan, Vijayaraghavan; Mendoza, Ordetta Hannah; Kanimozhi, Mahalingam; Chun, Sechul; Pašić, Lejla

    2016-01-01

    Toxicity of chromium often impairs the remediation capacity of plants used in phytoremediation of polluted soils. In this study, we have identified Albizia lebbeck as a prospective chromium hyperaccumulator and examined cultivable diversity of endophytes present in chromium-treated and control saplings. High numbers (22-100%) of endophytic bacteria, isolated from root, stem, and leaf tissues, could tolerate elevated (1-3 mM) concentrations of K2CrO7. 16S rRNA gene sequence-based phylogenetic analysis showed that the 118 isolates obtained comprised of 17 operational taxonomic units affiliated with the proteobacterial genera Rhizobium (18%), Marinomonas (1%), Pseudomonas (16%), and Xanthomonas (7%) but also with members of Firmicutes genera, such as Bacillus (35%) and Salinococcus (3%). The novel isolates belonging to Salinococcus and Bacillus could tolerate high K2CrO7 concentrations (3 mM) and also showed elevated activity of chromate reductase. In addition, majority (%) of the endophytic isolates also showed production of indole-3-acetic acid. Taken together, our results indicate that the innate endophytic bacterial community assists plants in reducing heavy metal toxicity.

  3. Evaluation of two Brazilian indigenous plants for phytostabilization and phytoremediation of copper-contaminated soils.

    PubMed

    Andreazza, R; Bortolon, L; Pieniz, S; Bento, F M; Camargo, F A O

    2015-11-01

    Indigenous plants have been grown naturally and vigorously in copper contaminated soils. Thus, the aim of this study was to evaluate the phytoremediation ability of two indigenous plants naturally grown in two vineyard soils copper contaminated, and in a copper mining waste. However, it was evaluated the macro and micronutrient uptake and the potential of phytoremediation. So, a greenhouse study was carried out with Bidens pilosa and Plantago lanceolata in samples of vineyard soils (Inceptisol and Mollisol) copper contaminated, and in a copper mining waste. Plant growth, macro and micronutrient up take, tolerance index (TI), translocation factor (TF), metal extraction ratio (MER), bioaccumulation factor (BCF), plant effective number of the shoots (PENs), and plant effective number of the total plant (PENt) were analyzed. Both plants grown in vineyard soils showed high phytomass production and TI. P. lanceolata plants cultivated in the Inceptisol showed the highest copper concentrations in the shoots (142 mg kg-1), roots (964 mg kg-1) and entire plants (1,106 mg kg-1). High levels of copper were phytoaccumulated from the Inceptisol by B. pilosa and P. lanceolata with 3,500 and 2,200 g ha-1 respectively. Both B. pilosa and P. lanceolata plants showed characteristics of high copper hyperaccumulator. Results showed that both species play an important role in the natural copper phytoaccumulation in both vineyard soils contaminated with copper, being important to its phytoremediation.

  4. Phytoremediation of heavy metals--concepts and applications.

    PubMed

    Ali, Hazrat; Khan, Ezzat; Sajad, Muhammad Anwar

    2013-05-01

    The mobilization of heavy metals by man through extraction from ores and processing for different applications has led to the release of these elements into the environment. Since heavy metals are nonbiodegradable, they accumulate in the environment and subsequently contaminate the food chain. This contamination poses a risk to environmental and human health. Some heavy metals are carcinogenic, mutagenic, teratogenic and endocrine disruptors while others cause neurological and behavioral changes especially in children. Thus remediation of heavy metal pollution deserves due attention. Different physical and chemical methods used for this purpose suffer from serious limitations like high cost, intensive labor, alteration of soil properties and disturbance of soil native microflora. In contrast, phytoremediation is a better solution to the problem. Phytoremediation is the use of plants and associated soil microbes to reduce the concentrations or toxic effects of contaminants in the environments. It is a relatively recent technology and is perceived as cost-effective, efficient, novel, eco-friendly, and solar-driven technology with good public acceptance. Phytoremediation is an area of active current research. New efficient metal hyperaccumulators are being explored for applications in phytoremediation and phytomining. Molecular tools are being used to better understand the mechanisms of metal uptake, translocation, sequestration and tolerance in plants. This review article comprehensively discusses the background, concepts and future trends in phytoremediation of heavy metals.

  5. Exploring the Influence of Environmental Factors on Bacterial Communities within the Rhizosphere of the Cu-tolerant plant, Elsholtzia splendens

    PubMed Central

    Jiang, Longfei; Song, Mengke; Yang, Li; Zhang, Dayi; Sun, Yingtao; Shen, Zhenguo; Luo, Chunling; Zhang, Gan

    2016-01-01

    Bacterial communities of rhizospheric soils play an important role in the tolerance and uptake of metal-tolerant/hyperaccumulating plants to metals, e.g. the Cu-tolerant Elsholtzia splendens native to China. In this work, pyrosequencing of the bacterial 16S rRNA gene was firstly applied to investigate the rhizospheric bacterial community of E. splendens grown at Cu contaminated sites. The 47 phyla including 11 dominant phyla (>1%) in E. splendens rhizosphere were presented. The effects of Cu and other environmental factors (total organic carbon, total nitrogen and pH) on the rhizospheric bacterial community were studied comprehensively. The phyla abundances were affected by the environmental factors to different extent, and we found pH, instead of Cu concentration, influenced UniFrac distance significantly and was identified as the most important environmental factor affecting bacterial community. In addition, the influence of environmental factors on gene profiles was explored according to the predicted metagenomes obtained by PICRUSt (phylogenetic investigation of communities by reconstruction of unobserved states). Our study illustrates a view about Cu-tolerant E. splendens rhizospheric bacterial communities (composition, diversity and gene profiles) and their influencing factors, giving a hand for the understanding on bacterial community is formed and affected in rhizosphere. PMID:27782202

  6. Quantitative iTRAQ Proteomics Revealed Possible Roles for Antioxidant Proteins in Sorghum Aluminum Tolerance

    PubMed Central

    Zhou, Dangwei; Yang, Yong; Zhang, Jinbiao; Jiang, Fei; Craft, Eric; Thannhauser, Theodore W.; Kochian, Leon V.; Liu, Jiping

    2017-01-01

    Aluminum (Al) toxicity inhibits root growth and limits crop yields on acid soils worldwide. However, quantitative information is scarce on protein expression profiles under Al stress in crops. In this study, we report on the identification of potential Al responsive proteins from root tips of Al sensitive BR007 and Al tolerant SC566 sorghum lines using a strategy employing iTRAQ and 2D-liquid chromatography (LC) coupled to MS/MS (2D-LC-MS/MS). A total of 771 and 329 unique proteins with abundance changes of >1.5 or <0.67-fold were identified in BR007 and SC566, respectively. Protein interaction and pathway analyses indicated that proteins involved in the antioxidant system were more abundant in the tolerant line than in the sensitive one after Al treatment, while opposite trends were observed for proteins involved in lignin biosynthesis. Higher levels of ROS accumulation in root tips of the sensitive line due to decreased activity of antioxidant enzymes could lead to higher lignin production and hyper-accumulation of toxic Al in cell walls. These results indicated that activities of peroxidases and the balance between production and consumption of ROS could be important for Al tolerance and lignin biosynthesis in sorghum. PMID:28119720

  7. Anion Channel Inhibitor NPPB-Inhibited Fluoride Accumulation in Tea Plant (Camellia sinensis) Is Related to the Regulation of Ca2+, CaM and Depolarization of Plasma Membrane Potential

    PubMed Central

    Zhang, Xian-Chen; Gao, Hong-Jian; Yang, Tian-Yuan; Wu, Hong-Hong; Wang, Yu-Mei; Zhang, Zheng-Zhu; Wan, Xiao-Chun

    2016-01-01

    Tea plant is known to be a hyper-accumulator of fluoride (F). Over-intake of F has been shown to have adverse effects on human health, e.g., dental fluorosis. Thus, understanding the mechanisms fluoride accumulation and developing potential approaches to decrease F uptake in tea plants might be beneficial for human health. In the present study, we found that pretreatment with the anion channel inhibitor NPPB reduced F accumulation in tea plants. Simultaneously, we observed that NPPB triggered Ca2+ efflux from mature zone of tea root and significantly increased relative CaM in tea roots. Besides, pretreatment with the Ca2+ chelator (EGTA) and CaM antagonists (CPZ and TFP) suppressed NPPB-elevated cytosolic Ca2+ fluorescence intensity and CaM concentration in tea roots, respectively. Interestingly, NPPB-inhibited F accumulation was found to be significantly alleviated in tea plants pretreated with either Ca2+ chelator (EGTA) or CaM antagonists (CPZ and TFP). In addition, NPPB significantly depolarized membrane potential transiently and we argue that the net Ca2+ and H+ efflux across the plasma membrane contributed to the restoration of membrane potential. Overall, our results suggest that regulation of Ca2+-CaM and plasma membrane potential depolarization are involved in NPPB-inhibited F accumulation in tea plants. PMID:26742036

  8. Ectopic expression of RNF168 and 53BP1 increases mutagenic but not physiological non-homologous end joining

    PubMed Central

    Zong, Dali; Callén, Elsa; Pegoraro, Gianluca; Lukas, Claudia; Lukas, Jiri; Nussenzweig, André

    2015-01-01

    DNA double strand breaks (DSBs) formed during S phase are preferentially repaired by homologous recombination (HR), whereas G1 DSBs, such as those occurring during immunoglobulin class switch recombination (CSR), are repaired by non-homologous end joining (NHEJ). The DNA damage response proteins 53BP1 and BRCA1 regulate the balance between NHEJ and HR. 53BP1 promotes CSR in part by mediating synapsis of distal DNA ends, and in addition, inhibits 5’ end resection. BRCA1 antagonizes 53BP1 dependent DNA end-blocking activity during S phase, which would otherwise promote mutagenic NHEJ and genome instability. Recently, it was shown that supra-physiological levels of the E3 ubiquitin ligase RNF168 results in the hyper-accumulation of 53BP1/BRCA1 which accelerates DSB repair. Here, we ask whether increased expression of RNF168 or 53BP1 impacts physiological versus mutagenic NHEJ. We find that the anti-resection activities of 53BP1 are rate-limiting for mutagenic NHEJ but not for physiological CSR. As heterogeneity in the expression of RNF168 and 53BP1 is found in human tumors, our results suggest that deregulation of the RNF168/53BP1 pathway could alter the chemosensitivity of BRCA1 deficient tumors. PMID:25916843

  9. Tissue-Specific Apocarotenoid Glycosylation Contributes to Carotenoid Homeostasis in Arabidopsis Leaves.

    PubMed

    Lätari, Kira; Wüst, Florian; Hübner, Michaela; Schaub, Patrick; Beisel, Kim Gabriele; Matsubara, Shizue; Beyer, Peter; Welsch, Ralf

    2015-08-01

    Attaining defined steady-state carotenoid levels requires balancing of the rates governing their synthesis and metabolism. Phytoene formation mediated by phytoene synthase (PSY) is rate limiting in the biosynthesis of carotenoids, whereas carotenoid catabolism involves a multitude of nonenzymatic and enzymatic processes. We investigated carotenoid and apocarotenoid formation in Arabidopsis (Arabidopsis thaliana) in response to enhanced pathway flux upon PSY overexpression. This resulted in a dramatic accumulation of mainly β-carotene in roots and nongreen calli, whereas carotenoids remained unchanged in leaves. We show that, in chloroplasts, surplus PSY was partially soluble, localized in the stroma and, therefore, inactive, whereas the membrane-bound portion mediated a doubling of phytoene synthesis rates. Increased pathway flux was not compensated by enhanced generation of long-chain apocarotenals but resulted in higher levels of C13 apocarotenoid glycosides (AGs). Using mutant lines deficient in carotenoid cleavage dioxygenases (CCDs), we identified CCD4 as being mainly responsible for the majority of AGs formed. Moreover, changed AG patterns in the carotene hydroxylase mutants lutein deficient1 (lut1) and lut5 exhibiting altered leaf carotenoids allowed us to define specific xanthophyll species as precursors for the apocarotenoid aglycons detected. In contrast to leaves, carotenoid hyperaccumulating roots contained higher levels of β-carotene-derived apocarotenals, whereas AGs were absent. These contrasting responses are associated with tissue-specific capacities to synthesize xanthophylls, which thus determine the modes of carotenoid accumulation and apocarotenoid formation.

  10. Determining soil enzyme activities for the assessment of fungi and citric acid-assisted phytoextraction under cadmium and lead contamination.

    PubMed

    Mao, Liang; Tang, Dong; Feng, Haiwei; Gao, Yang; Zhou, Pei; Xu, Lurong; Wang, Lumei

    2015-12-01

    Microorganism or chelate-assisted phytoextraction is an effective remediation tool for heavy metal polluted soil, but investigations into its impact on soil microbial activity are rarely reported. Consequently, cadmium (Cd)- and lead (Pb)-resistant fungi and citric acid (CA) were introduced to enhance phytoextraction by Solanum nigrum L. under varied Cd and Pb pollution levels in a greenhouse pot experiment. We then determined accumulation of Cd and Pb in S. nigrum and the soil enzyme activities of dehydrogenase, phosphatase, urease, catalase, sucrase, and amylase. Detrended canonical correspondence analysis (DCCA) was applied to assess the interactions between remediation strategies and soil enzyme activities. Results indicated that the addition of fungi, CA, or their combination enhanced the root biomass of S. nigrum, especially at the high-pollution level. The combined treatment of CA and fungi enhanced accumulation of Cd about 22-47 % and of Pb about 13-105 % in S. nigrum compared with the phytoextraction alone. However, S. nigrum was not shown to be a hyperaccumulator for Pb. Most enzyme activities were enhanced after remediation. The DCCA ordination graph showed increasing enzyme activity improvement by remediation in the order of phosphatase, amylase, catalase, dehydrogenase, and urease. Responses of soil enzyme activities were similar for both the addition of fungi and that of CA. In summary, results suggest that fungi and CA-assisted phytoextraction is a promising approach to restoring heavy metal polluted soil.

  11. Potential phytoextraction and phytostabilization of perennial peanut on copper-contaminated vineyard soils and copper mining waste.

    PubMed

    Andreazza, Robson; Bortolon, Leandro; Pieniz, Simone; Giacometti, Marcelo; Roehrs, Dione D; Lambais, Mácio R; Camargo, Flávio A O

    2011-12-01

    This study sought to evaluate the potential of perennial peanut (Arachis pintoi) for copper phytoremediation in vineyard soils (Inceptisol and Mollisol) contaminated with copper and copper mining waste. Our results showed high phytomass production of perennial peanut in both vineyard soils. Macronutrient uptakes were not negatively affected by perennial peanut cultivated in all contaminated soils. Plants cultivated in Mollisol showed high copper concentrations in the roots and shoots of 475 and 52 mg kg(-1), respectively. Perennial peanut plants showed low translocation factor values for Cu, although these plants showed high bioaccumulation factor (BCF) for both vineyard soils, Inceptisol and Mollisol, with BCF values of 3.83 and 3.24, respectively, being characterized as a copper hyperaccumulator plant in these soils. Copper phytoextraction from Inceptisol soil was the highest for both roots and entire plant biomass, with more than 800 mg kg(-1) of copper in whole plant. The highest potential copper phytoextraction by perennial peanut was in Inceptisol soil with copper removal of 2,500 g ha(-1). Also, perennial peanut showed high potential for copper phytoremoval in copper mining waste and Mollisol with 1,700 and 1,500 g of copper per hectare, respectively. In addition, perennial peanuts characterized high potential for phytoextraction and phytostabilization of copper in vineyard soils and copper mining waste.

  12. Effects of the halophytes Tecticornia indica and Suaeda fruticosa on soil enzyme activities in a Mediterranean Sabkha.

    PubMed

    Ouni, Youssef; Lakhdar, Abdelbasset; Rabhi, Mokded; Smaoui, Abderrazak; Maria, A Rao; Chedly, Abdelly

    2013-01-01

    In the present work, we studied the effectiveness of the predominant halophytes of Soliman sabkha (Tecticornia indica and Suaeda fruticosa) to promote soil biological activities and ecosystem productivity. Soil Arylsulphatese ARY, beta-glucosidase beta-GLU, phosphatase PHO, invertase INV, urease URE, and dehydogenase DES activities in Extra- and Intra-tuft halophytes and plant productivity were assessed. Results revealed a high increase of microbial community and ARY, beta-GLU, PHO, INV URE and DES activities (+298%, +400%, +800%, +350%, +320%, +25% and +759%, respectively) in Intra-tuft rhizosphere as compared to Extra-tuft one, which is likely due to the significant decrease of salinity in the rhizosphere of Tecticornia indica and Suaeda fruticosa. Both perennial plants exhibited high productivities (7.4 t dry weight ha(-1) and 2.2 t dry weight ha(-1), respectively) and Na+-hyperaccumulating capacities (0.75 t Na+ ha(-1) and 0.22 t Na+ ha(-1), respectively), reducing salt constraint and favouring soil fertility. This constitutes a promising alternative to enhance productivity in such a salt-affected biotope by offering suitable microhabitat for annual glycophytes.

  13. Irrigation of three wetland species and a hyperaccumlating fern with arsenic-laden solutions: observations of growth, arsenic uptake, nutrient status, and chlorophyll content.

    PubMed

    Rofkar, Jordan R; Dwyer, Daryl F

    2013-01-01

    Engineered wetlands can be an integral part of a treatment strategy for remediating arsenic-contaminated wastewater, wherein, As is removed by adsorption to soil particles, chemical transformation, precipitation, or accumulation by plants. The remediation process could be optimized by choosing plant species that take up As throughout the seasonal growing period. This report details experiments that utilize wetland plant species native to Ohio (Carex stricta, Pycnanthemum virginianum, and Spartina pectinata) that exhibit seasonally related maximal growth rates, plus one hyperaccumulating fern (Pteris vittata) that was used to compare arsenic tolerance. All plants were irrigated with control or As-laden nutrient solutions (either 0, 1.5, or 25 mg As L(-1)) for 52 d. Biomass, nutrient content, and chlorophyll content were compared between plants treated and control plants (n = 5). At the higher concentration of arsenic (25 mg L(-1)), plant biomass, leaf area, and total chlorophyll were all lower than values in control plants. A tolerance index, based on total plant biomass at the end of the experiment, indicated C. stricta (0.99) and S. pectinata (0.84) were more tolerant than the other plant species when irrigated with 1.5 mg As L(-1). These plant species can be considered as candidates for engineered wetlands.

  14. Complete genome analysis of Serratia marcescens RSC-14: A plant growth-promoting bacterium that alleviates cadmium stress in host plants

    PubMed Central

    Khan, Abdur Rahim; Park, Gun-Seok; Asaf, Sajjad; Hong, Sung-Jun; Jung, Byung Kwon

    2017-01-01

    Serratia marcescens RSC-14 is a Gram-negative bacterium that was previously isolated from the surface-sterilized roots of the Cd-hyperaccumulator Solanum nigrum. The strain stimulates plant growth and alleviates Cd stress in host plants. To investigate the genetic basis for these traits, the complete genome of RSC-14 was obtained by single-molecule real-time sequencing. The genome of S. marcescens RSC-14 comprised a 5.12-Mbp-long circular chromosome containing 4,593 predicted protein-coding genes, 22 rRNA genes, 88 tRNA genes, and 41 pseudogenes. It contained genes with potential functions in plant growth promotion, including genes involved in indole-3-acetic acid (IAA) biosynthesis, acetoin synthesis, and phosphate solubilization. Moreover, annotation using NCBI and Rapid Annotation using Subsystem Technology identified several genes that encode antioxidant enzymes as well as genes involved in antioxidant production, supporting the observed resistance towards heavy metals, such as Cd. The presence of IAA pathway-related genes and oxidative stress-responsive enzyme genes may explain the plant growth-promoting potential and Cd tolerance, respectively. This is the first report of a complete genome sequence of Cd-tolerant S. marcescens and its plant growth promotion pathway. The whole-genome analysis of this strain clarified the genetic basis underlying its phenotypic and biochemical characteristics, underpinning the beneficial interactions between RSC-14 and plants. PMID:28187139

  15. The use of vetiver for remediation of heavy metal soil contamination.

    PubMed

    Antiochia, Riccarda; Campanella, Luigi; Ghezzi, Paola; Movassaghi, K

    2007-06-01

    The use of Vetiveria zizanioides (vetiver) was studied to evaluate its efficiency for the remediation of soils contaminated by heavy metals. Vetiver plants were tested for Cr, Cu, Pb and Zn. Phytoextraction and bioremediation experiments were carried out by irrigating the vetiver plants and the dry plants with solutions containing suitable amounts of Cr, Cu, Pd and Zn. The concentrations of the heavy metals were determined in both experiments in shoot and root parts of vetiver plants using inductively coupled plasma atomic emission spectroscopy after a mineralization step. Phytoextraction experiments showed a poor efficiency of vetiver for Cr and Cu uptake (both less than 0.1% in shoots and roots after 30 days), but a quite high capability of Pb and Zn uptake (0.4% in shoots and 1% in roots for Pb and 1% both in shoots and in roots for Zn, after 30 days). For these reasons the vetiver plant can be considered a quite good "hyperaccumulator" only for Pb and Zn. As for bioremediation experiments, the vetiver plant showed heavy metal uptake values significantly lower than those obtained with other biological substrates.

  16. Comprehensive review on phytotechnology: Heavy metals removal by diverse aquatic plants species from wastewater.

    PubMed

    Rezania, Shahabaldin; Taib, Shazwin Mat; Md Din, Mohd Fadhil; Dahalan, Farrah Aini; Kamyab, Hesam

    2016-11-15

    Environmental pollution specifically water pollution is alarming both in the developed and developing countries. Heavy metal contamination of water resources is a critical issue which adversely affects humans, plants and animals. Phytoremediation is a cost-effective remediation technology which able to treat heavy metal polluted sites. This environmental friendly method has been successfully implemented in constructed wetland (CWs) which is able to restore the aquatic biosystem naturally. Nowadays, many aquatic plant species are being investigated to determine their potential and effectiveness for phytoremediation application, especially high growth rate plants i.e. macrophytes. Based on the findings, phytofiltration (rhizofiltration) is the sole method which defined as heavy metals removal from water by aquatic plants. Due to specific morphology and higher growth rate, free-floating plants were more efficient to uptake heavy metals in comparison with submerged and emergent plants. In this review, the potential of wide range of aquatic plant species with main focus on four well known species (hyper-accumulators): Pistia stratiotes, Eicchornia spp., Lemna spp. and Salvinia spp. was investigated. Moreover, we discussed about the history, methods and future prospects in phytoremediation of heavy metals by aquatic plants comprehensively.

  17. Interaction of SOS2 with nucleoside diphosphate kinase 2 and catalases reveals a point of connection between salt stress and H2O2 signaling in Arabidopsis thaliana.

    PubMed

    Verslues, Paul E; Batelli, Giorgia; Grillo, Stefania; Agius, Fernanda; Kim, Yong-Sig; Zhu, Jianhua; Agarwal, Manu; Katiyar-Agarwal, Surekha; Zhu, Jian-Kang

    2007-11-01

    SOS2, a class 3 sucrose-nonfermenting 1-related kinase, has emerged as an important mediator of salt stress response and stress signaling through its interactions with proteins involved in membrane transport and in regulation of stress responses. We have identified additional SOS2-interacting proteins that suggest a connection between SOS2 and reactive oxygen signaling. SOS2 was found to interact with the H2O2 signaling protein nucleoside diphosphate kinase 2 (NDPK2) and to inhibit its autophosphorylation activity. A sos2-2 ndpk2 double mutant was more salt sensitive than a sos2-2 single mutant, suggesting that NDPK2 and H2O2 are involved in salt resistance. However, the double mutant did not hyperaccumulate H2O2 in response to salt stress, suggesting that it is altered signaling rather than H2O2 toxicity alone that is responsible for the increased salt sensitivity of the sos2-2 ndpk2 double mutant. SOS2 was also found to interact with catalase 2 (CAT2) and CAT3, further connecting SOS2 to H2O2 metabolism and signaling. The interaction of SOS2 with both NDPK2 and CATs reveals a point of cross talk between salt stress response and other signaling factors including H2O2.

  18. Germin-like protein 2 gene promoter from rice is responsive to fungal pathogens in transgenic potato plants.

    PubMed

    Munir, Faiza; Hayashi, Satomi; Batley, Jacqueline; Naqvi, Syed Muhammad Saqlan; Mahmood, Tariq

    2016-01-01

    Controlled transgene expression via a promoter is particularly triggered in response to pathogen infiltration. This is significant for eliciting disease-resistant features in crops through genetic engineering. The germins and germin-like proteins (GLPs) are known to be associated with plant and developmental stages. The 1107-bp Oryza sativa root GLP2 (OsRGLP2) gene promoter fused to a β-glucuronidase (GUS) reporter gene was transformed into potato plants through an Agrobacterium-mediated transformation. The OsRGLP2 promoter was activated in response to Fusarium solani (Mart.) Sacc. and Alternaria solani Sorauer. Quantitative real-time PCR results revealed 4-5-fold increase in promoter activity every 24 h following infection. There was a 15-fold increase in OsRGLP2 promoter activity after 72 h of F. solani (Mart.) Sacc. treatment and a 12-fold increase observed with A. solani Sorauer. Our results confirmed that the OsRGLP2 promoter activity was enhanced under fungal stress. Furthermore, a hyperaccumulation of H2O2 in transgenic plants is a clear signal for the involvement of OsRGLP2 promoter region in the activation of specific genes in the potato genome involved in H2O2-mediated defense response. The OsRGLP2 promoter evidently harbors copies of GT-I and Dof transcription factors (AAAG) that act in response to elicitors generated in the wake of pathogen infection.

  19. Proteomic changes in maize as a response to heavy metal (lead) stress revealed by iTRAQ quantitative proteomics.

    PubMed

    Li, G K; Gao, J; Peng, H; Shen, Y O; Ding, H P; Zhang, Z M; Pan, G T; Lin, H J

    2016-01-26

    Lead (Pb), a heavy metal, has become a crucial pollutant in soil and water, causing not only permanent and irreversible health problems, but also substantial reduction in crop yields. In this study, we conducted proteome analysis of the roots of the non-hyperaccumulator inbred maize line 9782 at four developmental stages (0, 12, 24, and 48 h) under Pb pollution using isobaric tags for relative and absolute quantification technology. A total of 252, 72 and 116 proteins were differentially expressed between M12 (after 12-h Pb treatment) and CK (water-mocked treatment), M24 (after 24-h Pb treatment) and CK, and M48 (after 48-h Pb treatment) and CK, respectively. In addition, 14 differentially expressed proteins were common within each comparison group. Moreover, Cluster of Orthologous Groups enrichment analysis revealed predominance of the proteins involved in posttranslational modification, protein turnover, and chaperones. Additionally, the changes in protein profiles showed a lower concordance with corresponding alterations in transcript levels, indicating important roles for transcriptional and posttranscriptional regulation in the response of maize roots to Pb pollution. Furthermore, enriched functional categories between the successive comparisons showed that the proteins in functional categories of stress, redox, signaling, and transport were highly up-regulated, while those in the functional categories of nucleotide metabolism, amino acid metabolism, RNA, and protein metabolism were down-regulated. This information will help in furthering our understanding of the detailed mechanisms of plant responses to heavy metal stress by combining protein and mRNA profiles.

  20. Mitochondrial function is an inducible determinant of osmotic stress adaptation in yeast.

    PubMed

    Pastor, Mar Martínez; Proft, Markus; Pascual-Ahuir, Amparo

    2009-10-30

    Hyperosmotic stress triggers a great variety of adaptive responses in eukaryotic cells that affect many different physiological functions. Here we investigate the role of the mitochondria during osmostress adaptation in budding yeast. Mitochondrial function is generally required for proper salt and osmotic stress adaptation because mutants with defects in many different mitochondrial components show hypersensitivity to increased NaCl and KCl concentrations. Mitochondrial protein abundance rapidly increases upon osmoshock in a selective manner, because it affects Calvin cycle enzymes (Sdh2 and Cit1) and components of the electron transport chain (Cox6) but not the ATP synthase