| molecular physiology of zinc transport in the zn hyperaccumulator thlaspi caerulescens. | in this manuscript, recent research from this laboratory into physiological and molecular aspects of heavy metal (zn) transport in the hyperaccumulating plant species, thlaspi caerulescens is reviewed. this research is aimed at elucidating the processes that underlie the accumulation of extraordinarily high levels of zn in the t. caerulescens shoot (up to 3% zn dry wt.) without any associated toxicity symptom. physiological studies focused on the use of radiotracer flux techniques (65zn2+) to ch ... | 2000 | 10938797 |
| cellular compartmentation of zinc in leaves of the hyperaccumulator thlaspi caerulescens | cellular compartmentation of zn in the leaves of the hyperaccumulator thlaspi caerulescens was investigated using energy-dispersive x-ray microanalysis and single-cell sap extraction. energy-dispersive x-ray microanalysis of frozen, hydrated leaf tissues showed greatly enhanced zn accumulation in the epidermis compared with the mesophyll cells. the relative zn concentration in the epidermal cells correlated linearly with cell length in both young and mature leaves, suggesting that vacuolation of ... | 1999 | 9880373 |
| bioengineering of a phytoremediation plant by means of somatic hybridization. | phytoremediation is a technology that exploits a plant's ability to remove contaminants from the environment or render toxic compounds harmless. an efficient metal phytoremediating plant must combine high biomass production and established cultivation methods with high tolerance to a specific contaminant and ability for root uptake, translocation, and compartmentalization of contaminants in the above-ground biomass. symmetric and asymmetric somatic hybridizations were used to introduce toxic met ... | 2002 | 12655805 |
| organic acid complexation, heavy metal distribution and the effect of atpase inhibition in hairy roots of hyperaccumulator plant species. | heavy metal uptake and distribution were investigated in hairy roots of the cd hyperaccumulator, thlaspi caerulescens, and the ni hyperaccumulator, alyssum bertolonii. hairy roots of both species contained high constitutive levels of citric, malic and malonic acids. after treatment with 20 ppm cd or 25 ppm ni, about 13% of the total cd in t. caerulescens roots and 28% of the total ni in a. bertolonii were associated with organic acids. t. caerulescens and a. bertolonii hairy roots remained healt ... | 2003 | 12568742 |
| new insights into photosynthetic oscillations revealed by two-dimensional microscopic measurements of chlorophyll fluorescence kinetics in intact leaves and isolated protoplasts. | chlorophyll fluorescence kinetic microscopy was used to analyze photosynthetic oscillations in individual cells of leaves and in isolated leaf cell protoplasts. four brassicaceae species were used: arabidopsis halleri (l.) o'kane & al-shehbaz, thlaspi fendleri (nels.) hitchc, thlaspi caerulescens j.&c. presl and thlaspi ochroleucum boiss et helder. with the latter two, the measurements were extended also to isolated protoplasts. the oscillations were induced under the microscope by exposing dark ... | 2002 | 12462644 |
| physiological characterization of root zn2+ absorption and translocation to shoots in zn hyperaccumulator and nonaccumulator species of thlaspi. | radiotracer techniques were employed to characterize 65zn2+ influx into the root symplasm and translocation to the shoot in thlaspi caerulescens, a zn hyperaccumulator, and thlaspi arvense, a nonaccumulator. a protocol was developed that allowed us to quantify unidirectional 65zn2+ influx across the root-cell plasma membrane (20 min of radioactive uptake followed by 15 min of desorption in a 100 [mu]m zncl2 + 5 mm cacl2 solution). concentration-dependent zn2+ influx in both thlaspi species yield ... | 1996 | 12226473 |
| influence of iron status on cadmium and zinc uptake by different ecotypes of the hyperaccumulator thlaspi caerulescens. | we have previously identified an ecotype of the hyperaccumulator thlaspi caerulescens (ganges), which is far superior to other ecotypes (including prayon) in cd uptake. in this study, we investigated the effect of fe status on the uptake of cd and zn in the ganges and prayon ecotypes, and the kinetics of cd and zn influx using radioisotopes. furthermore, the t. caerulescens zip (zn-regulated transporter/fe-regulated transporter-like protein) genes tcznt1-g and tcirt1-g were cloned from the gange ... | 2002 | 11950984 |
| phytochelatin synthesis is not responsible for cd tolerance in the zn/cd hyperaccumulator thlaspi caerulescens (j. & c. presl). | thlaspi caerulescens (j. & c. presl, "prayon") is a heavy-metal hyperaccumulator that accumulates zn and cd to high concentrations (40,000 and 4,000 mg kg dw-1 respectively) without phytotoxicity. the mechanism of cd tolerance has not been characterized but reportedly involves vacuolar sequestration. the role of phytochelatins (pcs) in metal tolerance in t. caerulescens and the related non-accumulator t. arvense was examined. although pcs were produced by both species in response to cd, these pe ... | 2002 | 11925047 |
| characteristics of cadmium uptake in two contrasting ecotypes of the hyperaccumulator thlaspi caerulescens. | uptake of cd and zn by intact seedlings of two contrasting ecotypes of the hyperaccumulator thlaspi caerulescens was characterized using radioactive tracers. uptake of cd and zn at 2 degrees c was assumed to represent mainly apoplastic binding in the roots, whereas the difference in uptake between 22 degrees c and 2 degrees c represented metabolically dependent influx. there was no significant difference between the two ecotypes in the apoplastic binding of cd or zn. metabolically dependent upta ... | 2002 | 11847252 |
| phytoremediation of heavy metal-contaminated soils: natural hyperaccumulation versus chemically enhanced phytoextraction. | a pot experiment was conducted to compare two strategies of phytoremediation: natural phytoextraction using the zn and cd hyperaccumulator thlaspi caerulescens j. presl & c. presl versus chemically enhanced phytoextraction using maize (zea mays l.) treated with ethylenediaminetetraacetic acid (edta). the study used an industrially contaminated soil and an agricultural soil contaminated with metals from sewage sludge. three crops of t. caerulescens grown over 391 d removed more than 8 mg kg(-1) c ... | 2001 | 11789997 |
| influence of the zinc hyperaccumulator thlaspi caerulescens j. & c. presl. and the nonmetal accumulator trifolium pratense l. on soil microbial populations. | metal hyperaccumulator plants like thlaspi caerulescens j. & c. presl. are used for phytoremediation of contaminated soils. since little is known about the rhizosphere of hyperaccumulators, the influence of t. caerulescens was compared with the effects of trifolium pratense l. on soil microbes. high- and low-metal soils were collected near a zinc smelter in palmerton, penn. soil ph was adjusted to 5.8 and 6.8 by the addition of ca(oh)2. liming increased bacterial populations and decreased metal ... | 2001 | 11575505 |
| altered zn compartmentation in the root symplasm and stimulated zn absorption into the leaf as mechanisms involved in zn hyperaccumulation in thlaspi caerulescens | we investigated zn compartmentation in the root, zn transport into the xylem, and zn absorption into leaf cells in thlaspi caerulescens, a zn-hyperaccumulator species, and compared them with those of a related nonaccumulator species, thlaspi arvense. 65zn-compartmental analysis conducted with roots of the two species indicated that a significant fraction of symplasmic zn was stored in the root vacuole of t. arvense, and presumably became unavailable for loading into the xylem and subsequent tran ... | 1998 | 9808732 |
| changes in the rhizosphere of metal-accumulating plants evidenced by chemical extractants. | the plants salix viminalis l. (common osier) and thlaspi caerulescens j. presl & c. presl have been studied often because of their high potential to extract heavy metals from soils. the soil properties favoring this phytoextraction are not yet fully known. in this study we compared three frequently used single-extracting agents (nano3, diethylenetriaminepentaacetic acid [dtpa], and ethylenediaminetetra-acetic acid [edta]) with a sequential extraction procedure to describe changes in the differen ... | 2002 | 12371173 |
| determination of glucosinolates in rapeseed and thlaspi caerulescens plants by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry. | liquid chromatography-atmospheric pressure chemical ionization mass spectrometry was used to identify glucosinolates in plant extracts. optimization of the analytical conditions and the determination of the method detection limit was performed using commercial 2-propenylglucosinolate (sinigrin). optimal values for the following parameters were determined: nebulization pressure, gas temperature, flux of drying gas, capillar voltage, corona current and fragmentor conditions. the method detection l ... | 2000 | 10985538 |
| comparison of elemental composition and solubility in the zinc hyperaccumulator thlaspi caerulescens with the non-hyperaccumulator thlaspi ochroleucum. | | 2000 | 10903358 |
| effects of metal phytoextraction practices on the indigenous community of arbuscular mycorrhizal fungi at a metal-contaminated landfill. | phytoextraction involves use of plants to remove toxic metals from soil. we examined the effects of phytoextraction practices with three plant species (silene vulgaris, thlaspi caerulescens, and zea mays) and a factorial variation of soil amendments (either an ammonium or nitrate source of nitrogen and the presence or absence of an elemental sulfur supplement) on arbuscular mycorrhizal (am) fungi (glomales, zygomycetes) at a moderately metal-contaminated landfill located in st. paul, minn. speci ... | 2000 | 10831433 |
| the role of phytochelatins in constitutive and adaptive heavy metal tolerances in hyperaccumulator and non-hyperaccumulator metallophytes. | using the gamma-glutamylcysteine synthetase inhibitor, l-buthionine-[s,r]-sulphoximine (bso), the role for phytochelatins (pcs) was evaluated in cu, cd, zn, as, ni, and co tolerance in non-metallicolous and metallicolous, hypertolerant populations of silene vulgaris (moench) garcke, thlaspi caerulescens j.&c. presl., holcus lanatus l., and agrostis castellana boiss. et reuter. based on plant-internal pc-thiol to metal molar ratios, the metals' tendency to induce pc accumulation decreased in the ... | 2002 | 12432030 |
| the molecular physiology of heavy metal transport in the zn/cd hyperaccumulator thlaspi caerulescens. | an integrated molecular and physiological investigation of the fundamental mechanisms of heavy metal accumulation was conducted in thlaspi caerulescens, a zn/cd-hyperaccumulating plant species. a heavy metal transporter cdna, znt1, was cloned from t. caerulescens through functional complementation in yeast and was shown to mediate high-affinity zn(2+) uptake as well as low-affinity cd(2+) uptake. it was found that this transporter is expressed at very high levels in roots and shoots of the hyper ... | 2000 | 10781104 |
| hyperaccumulation of cadmium by hairy roots of thlaspi caerulescens. | 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(+)-atpase inhibitor. the highest equilibrium cd content measured in t. caerulescens roots was 62,800 microg g(-1 ... | 2000 | 10649235 |
| hyperaccumulation of cadmium and zinc in thlaspi caerulescens and arabidopsis halleri at the leaf cellular level. | vacuolar compartmentalization or cell wall binding in leaves could play a major role in hyperaccumulation of heavy metals. however, little is known about the physiology of intracellular cadmium (cd) sequestration in plants. we investigated the role of the leaf cells in allocating metal in hyperaccumulating plants by measuring short-term (109)cd and (65)zn uptake in mesophyll protoplasts of thlaspi caerulescens "ganges" and arabidopsis halleri, both hyperaccumulators of zinc (zn) and cd, and t. c ... | 2004 | 14730081 |
| arabis gemmifera is a hyperaccumulator of cd and zn. | hyperaccumulators are essential for phytoremediation of heavy metals. in europe and north america, many studies have been conducted to find more effective plants for phytoremediation of various pollutants. in japan, this field of research has just recently come more into focus. a type of fern in japan, athyrium yokoscense, is well known as a hyperaccumulator of cd and zn. however, it is not suitable for phytoremediation because it is a summer green and grows slowly. therefore, in order to find h ... | 2003 | 14750427 |
| tissue- and age-dependent differences in the complexation of cadmium and zinc in the cadmium/zinc hyperaccumulator thlaspi caerulescens (ganges ecotype) revealed by x-ray absorption spectroscopy. | extended x-ray absorption fine structure measurements were performed on frozen hydrated samples of the cadmium (cd)/zinc (zn) hyperaccumulator thlaspi caerulescens (ganges ecotype) after 6 months of zn(2+) treatment with and without addition of cd(2+). ligands depended on the metal and the function and age of the plant tissue. in mature and senescent leaves, oxygen ligands dominated. this result combined with earlier knowledge about metal compartmentation indicates that the plants prefer to deto ... | 2004 | 14966248 |
| isolation, characterization, and identification of bacteria associated with the zinc hyperaccumulator thlaspi caerulescens subsp. calaminaria. | we investigated bacterial populations associated with the zn hyperaccumulator thlaspi caerulescens subsp. calaminaria grown in a soil collected from an abandoned zn-pb mine and smelter in plombières, belgium. the bacterial population of the nonrhizospheric soil consisted of typical soil bacteria, some exhibiting multiple heavy-metal resistance characteristics that often are associated with polluted substrates: 7.8% and 4% of the population survived in the presence of elevated levels of zn (1 mm) ... | 2002 | 12655804 |
| soil solution zn and ph dynamics in non-rhizosphere soil and in the rhizosphere of thlaspi caerulescens grown in a zn/cd-contaminated soil. | temporal changes in soil solution properties and metal speciation were studied in non-rhizosphere soil and in the rhizosphere of the hyperaccumulator thlaspi caerulescens j. & c. presl (population from prayon, belgium) grown in a zn- and cd-contaminated soil. this paper focuses on soil solution zn and ph dynamics during phytoextraction. the concentration of zn in both non-rhizosphere and rhizosphere soil solutions decreased from 23 mg/l at the beginning to 2 mg/l at the end of the experiment (84 ... | 2000 | 10819195 |
| hyperaccumulation of metals by thlaspi caerulescens as affected by root development and cd-zn/ca-mg interactions. | the aim of this work was to study, in a rhizobox experiment, the phytoextraction of metals by the hyperaccumulator plant thlaspi caerulescens in relation to the heterogeneity of metal pollution. six treatments were designed with soils containing various levels of metals. homogeneous soils and inclusions of soils in other soil matrices were prepared in order to vary metal concentration and localization. growth parameters of the plant (rosette diameter and shoot biomass) and localization of roots ... | 2004 | 15224775 |
| a novel cpx-atpase from the cadmium hyperaccumulator thlaspi caerulescens. | thlaspi caerulescens exhibits a unique capacity for cadmium tolerance and accumulation. we investigated the molecular basis of this exceptional cd(2+) tolerance by screening for t. caerulescens genes, which alleviate cd(2+) toxicity upon expression in saccharomyces cerevisiae. this allowed for the isolation of a cdna encoding a peptide with homology to the c-terminal part of a heavy metal atpase. the corresponding tchma4 full-length sequence was isolated from t. caerulescens and compared to its ... | 2004 | 15225623 |
| metal availability and soil toxicity after repeated croppings of thlaspi caerulescens in metal contaminated soils. | metal phytoextraction with hyperaccumulating plants could be a useful method to decontaminate soils, but it is not fully validated yet. in order to quantify the efficiency of cd and zn extraction from a calcareous soil with and without fe amendment and an acidic soil, we performed a pot experiment with three successive croppings of thlaspi caerulescens followed by 3 months without plant and 7 weeks with lettuce. we used a combined approach to assess total extraction efficiency (2 m hno3-extracta ... | 2004 | 15234091 |
| identification of thlaspi caerulescens genes that may be involved in heavy metal hyperaccumulation and tolerance. characterization of a novel heavy metal transporting atpase. | thlaspi caerulescens is a heavy metal hyperaccumulator plant species that is able to accumulate extremely high levels of zinc (zn) and cadmium (cd) in its shoots (30,000 microg g(-1) zn and 10,000 microg g(-1) cd), and has been the subject of intense research as a model plant to gain a better understanding of the mechanisms of heavy metal hyperaccumulation and tolerance and as a source of genes for developing plant species better suited for the phytoremediation of metal-contaminated soils. in th ... | 2004 | 15516513 |
| subcellular localisation of cd and zn in the leaves of a cd-hyperaccumulating ecotype of thlaspi caerulescens. | thlaspi caerulescens (ganges ecotype) is able to accumulate large concentrations of cadmium (cd) and zinc (zn) in the leaves without showing any toxicity, suggesting a strong internal detoxification. the distribution of cd and zn in the leaves was investigated in the present study. although the cd and zn concentrations in the epidermal tissues were 2-fold higher than those of mesophyll tissues, 65-70% of total leaf cd and zn were distributed in the mesophyll tissues, suggesting that mesophyll is ... | 2005 | 15517354 |
| evidence for copper homeostasis function of metallothionein (mt3) in the hyperaccumulator thlaspi caerulescens. | metallothioneins chelate metals and consequently may be a control point of metal homeostasis. homologous to type 3 metallothioneins, tcmt3 cdna was identified in the cd/zn hyperaccumulator, thlaspi caerulescens. tcmt3 amino acid sequence showed modifications in the cys positions when compared with its arabidopsis orthologue. a structural model established that the mt3 carboxyterminal domain is similar to the beta domain of animal metallothioneins and predicts a smaller cavity to chelate metals f ... | 2004 | 15527754 |
| hyperaccumulation of zn by thlaspi caerulescens can ameliorate zn toxicity in the rhizosphere of cocropped thlaspi arvense. | the metal hyperaccumulating plant thlaspi caerulescens is effective in depleting plant-available metals from the soil. we hypothesized that this reduction of toxic metals in the rhizosphere of t. caerulescens would increase the growth of less metal-tolerant plants with their roots permitted to intermingle and develop coincident rhizospheres. the extent of rhizosphere interaction between t. caerulescens and a coplanted nonaccumulator species, thlaspi arvense, was controlled using barriers. two me ... | 2001 | 11506012 |
| an improved understanding of soil cd risk to humans and low cost methods to phytoextract cd from contaminated soils to prevent soil cd risks. | we believe greater consideration should be given the agronomic and nutritional/bioavailability factors that influence risk from cd-contaminated soils. we have argued that the ability of rice to accumulate soil cd in grain while excluding fe, zn and ca (even though the soil contains 100-times more zn than cd) was important in adverse effects of soil cd is farm families in asia. further, polished rice grain is deficient in fe, zn and ca for humans, which promotes cd absorption into duodenal cells. ... | 2004 | 15688862 |
| rhizosphere bacteria mobilize zn for hyperaccumulation by thlaspi caerulescens. | thlaspi caerulescens has a remarkable ability to hyperaccumulate zn from soils containing mostly nonlabile zn. the present study shows that rhizosphere microbes play an important role in increasing the availability of water-soluble zn in soil, thus enhancing zn accumulation by t. caerulescens. the addition of bacteria to surface-sterilized seeds of t. caerulescens sown in autoclaved soil increased the zn concentration in shoots 2-fold as compared to axenic controls; the total accumulation of zn ... | 2001 | 11505990 |
| distribution of cadmium in leaves of thlaspi caerulescens. | knowledge of the intracellular distribution of cd in leaves is necessary in order to understand the mechanisms of hyperaccumulation in thlaspi caerulescens. ganges and prayon, two ecotypes accumulating cd to different levels, were grown in nutrient medium containing varying concentrations (0, 5, 10, 50, and 100 microm) of cd. several different approaches were combined in this study to (i) validate the results obtained by a specific method and (ii) establish the link between observations and meas ... | 2005 | 15642714 |
| differences in whole-cell and single-channel ion currents across the plasma membrane of mesophyll cells from two closely related thlaspi species. | the patch clamp technique was used to study the physiology of ion transport in mesophyll cells from two thlaspi spp. that differ significantly in their physiology. in comparison with thlaspi arvense, thlaspi caerulescens (a heavy metal accumulator) can grow in, tolerate, and accumulate very high levels of certain heavy metals (primarily zinc [zn] and cadmium) in their leaf cells. the membrane conductance of every t. arvense leaf cell was dominated by a slowly activating, time-dependent outward r ... | 2003 | 12586882 |
| constitutively elevated salicylic acid signals glutathione-mediated nickel tolerance in thlaspi nickel hyperaccumulators. | progress is being made in understanding the biochemical and molecular basis of nickel (ni)/zinc (zn) hyperaccumulation in thlaspi; however, the molecular signaling pathways that control these mechanisms are not understood. we observed that elevated concentrations of salicylic acid (sa), a molecule known to be involved in signaling induced pathogen defense responses in plants, is a strong predictor of ni hyperaccumulation in the six diverse thlaspi species investigated, including the hyperaccumul ... | 2005 | 15734913 |
| phytoextraction of zn and cu from sewage sludge and impact on agronomic characteristics. | the presence of elevated concentrations of heavy metals limits the usage of sewage sludge as a fertilizer and soil amendment. experiments were carried out to examine the extent to which seven plant species phytoextracted zn and cu from dewatered sludge. the hyperaccumulators thlaspi caerulescens and sedum alfredii showed the greatest removal of zn, while shoots and tubers of two species of alocasia showed the greatest cu removal. cultivation of plants in the sludge resulted in significant decrea ... | 2005 | 15792302 |
| cadmium tolerance and antioxidative defenses in hairy roots of the cadmium hyperaccumulator, thlaspi caerulescens. | plant species capable of hyperaccumulating heavy metals are of considerable interest for phytoremediation and phytomining. this work aims to identify the role of antioxidative metabolism in heavy metal tolerance in the cd hyperaccumulator, thlaspi caerulescens. hairy roots of t. caerulescens and the non-hyperaccumulator, nicotiana tabacum (tobacco), were used to test the effects of high cd environments. in the absence of cd, endogenous activities of catalase were two to three orders of magnitude ... | 2003 | 12768621 |
| phytochelatin synthase (pcs) protein is induced in brassica juncea leaves after prolonged cd exposure. | higher plants respond to cadmium exposure with the production of phytochelatins (pcn), small heavy metal binding peptides, which are synthesized from glutathione by phytochelatin synthase (pcs). the isolation of a pcs cdna clone from brassica juncea l. cv. vitasso, a candidate species for phytoremediation, is reported here. clustal analysis revealed a close relationship of bjpcs1 with pcs proteins from arabidopsis thaliana and thlaspi caerulescens. bjpcs1 expressed as recombinant protein in e. c ... | 2003 | 12815036 |
| identification of the form of cd in the leaves of a superior cd-accumulating ecotype of thlaspi caerulescens using 113cd-nmr. | thlaspi caerulescens (ganges ecotype) is a known cd hyperaccumulator, however, the ligands which coordinate to cd ions in the leaves have not been identified. in the present study, the chemical form of cd was investigated by using 113cd-nuclear magnetic resonance (nmr) spectroscopy. plants were grown hydroponically with a highly enriched 113cd stable isotope. measurements of 113cd-nmr with intact leaves showed a signal at the chemical shift of around -16 ppm. crude leaf sap also gave a similar c ... | 2005 | 15883836 |
| palatability of thlaspi caerulescens for snails: influence of zinc and glucosinolates. | * the hypothesis that zinc (zn) hyperaccumulation defends thlaspi caerulescens against herbivores is tested with the snail helix aspersa. we investigated the effects of leaf zinc, cadmium, glucosinolate, nitrogen and dry matter concentrations on the feeding preferences of snails. * four t. caerulescens populations from southern france (two from metalliferous and two from normal soils) were grown on low- and high-zn soils to obtain contrasting leaf zn concentrations. plants were also collected in ... | 2005 | 15720687 |
| speciation of nickel in a hyperaccumulating plant by high-performance liquid chromatography-inductively coupled plasma mass spectrometry and electrospray ms/ms assisted by cloning using yeast complementation. | a novel analytical approach based on a combination of multidimensional hyphenated techniques and cloning of the ni-resistance gene using yeast complementation screens was developed for the identification of nickel species in a thlaspi caerulescens hyperaccumulating plant. the presence of an unknown strong ni complex was demonstrated by size exclusion hplc-capillary electrophoresis with icpms detection. the ni-containing peak was characterized by electrospray ms (m/z 360) and shown by collision-i ... | 2003 | 12948144 |
| comparative 16s rdna and 16s rrna sequence analysis indicates that actinobacteria might be a dominant part of the metabolically active bacteria in heavy metal-contaminated bulk and rhizosphere soil. | bacterial diversity in 16s ribosomal dna and reverse-transcribed 16s rrna clone libraries originating from the heavy metal-contaminated rhizosphere of the metal-hyperaccumulating plant thlaspi caerulescens was analysed and compared with that of contaminated bulk soil. partial sequence analysis of 282 clones revealed that most of the environmental sequences in both soils affiliated with five major phylogenetic groups, the actinobacteria, alpha-proteobacteria, beta-proteobacteria, acidobacteria an ... | 2003 | 14510843 |
| zinc tolerance and hyperaccumulation in f1 and f2 offspring from intra and interecotype crosses of thlaspi caerulescens. | the relationship between zinc (zn) tolerance and hyperaccumulation in thlaspi caerulescens was investigated from f1 and f2 crosses within and among metallicolous and nonmetallicolous mediterranean populations. f1 offspring were grown on increasingly zn-enriched soils to test zn enrichment effects, and many families of f2 offspring were grown on a zn-rich soil. tolerance of f1 offspring depended on stress intensity. tolerance of interecotype crosses was intermediate between that of the intraecoty ... | 2005 | 15720626 |
| variations in plant metallothioneins: the heavy metal hyperaccumulator thlaspi caerulescens as a study case. | plant metallothioneins (mts) are extremely diverse and are thought to be involved in metal homeostasis or detoxification. thlaspi caerulescens is a model zn/cd hyperaccumulator and thus constitutes an ideal system to study the variability of these mts. two t. caerulescens cdnas (accession: 665511; accession: 665515), that are highly homologous to type 1 and type 2 arabidopsis thaliana mts, have been isolated using a functional screen for plant cdnas that confer cd tolerance to yeast. however, tc ... | 2005 | 16052319 |
| cadmium hyperaccumulation protects thlaspi caerulescens from leaf feeding damage by thrips (frankliniella occidentalis). | metal hyperaccumulation has been proposed as a plant defensive strategy. here, we investigated whether cadmium (cd) hyperaccumulation protected thlaspi caerulescens from leaf feeding damage by thrips (frankliniella occidentalis). two ecotypes differing in cd accumulation, ganges (high) and prayon (low), were grown in compost amended with 0-1000 mg cd kg(-1) in two experiments under glasshouse conditions. f2 and f3 plants from the prayon x ganges crosses were grown with 5 mg cd kg(-1). plants wer ... | 2005 | 16101917 |
| cloning of three zip/nramp transporter genes from a ni hyperaccumulator plant thlaspi japonicum and their ni2+-transport abilities. | ni homeostasis is essential for plant cell activity, but the mechanisms of ni-transport and delivery are unknown. to elucidate the role of zip and nramp metal-transporters for ni2+-transport and homeostasis, we cloned their homologous genes from the ni hyperaccumulator thlaspi japonicum, and investigated their ni-transporting abilities by expression in yeast. the deduced amino acid sequences of the two zip transporter genes (tjznt1, tjznt2) and one nramp transporter gene cloned had high homologi ... | 2005 | 16198592 |
| field evaluation of cd and zn phytoextraction potential by the hyperaccumulators thlaspi caerulescens and arabidopsis halleri. | field trials were undertaken to investigate the effect of the application of metal mobilizing agents, different sowing strategies and length of growing season on the extraction of cd and zn from soils by thlaspi caerulescens and arabidopsis halleri. none of the mobilizing agents used enhanced metal accumulation by t. caerulescens. between 1998 and 2000, on average across plots where cd or zn exceeded allowable limits, t. caerulescens removed 1.3 and 0.3% of the total soil cd and zn. in one seaso ... | 2006 | 16202493 |
| nicotianamine over-accumulation confers resistance to nickel in arabidopsis thaliana. | nicotianamine is a methionine derivative involved in iron homeostasis, able to bind various other metals in vitro. to investigate its role in vivo, we expressed a nicotianamine synthase cdna (tcnas1) isolated from the polymetallic hyperaccumulator thlaspi caerulescens in arabidopsis thaliana. transgenic plants expressing tcnas1 over-accumulated na, up to 100-fold more than wild type plants. furthermore, increased na levels in different transgenic lines were quantitatively correlated with increas ... | 2005 | 16245165 |
| thlaspi caerulescens on nonmetalliferous soil in luxembourg: ecological niche and genetic variation in mineral element composition. | forty-seven populations of thlaspi caerulescens in luxembourg were characterised for population size, soil mineral element composition and other habitat characteristics. foliar concentrations of eight elements were assessed in 15 populations in the field and in eight populations cultivated in zinc (zn)-cadmium (cd)-nickel (ni)-enriched soil. t. caerulescens favoured stony soil developed on steep, south-facing emsian shale outcrops. all soil samples were nonmetalliferous. soil ph ranged from 4.2 ... | 2005 | 15720661 |
| effect of soil characteristics on cd uptake by the hyperaccumulator thlaspi caerulescens. | the influence of soil characteristics on the phytoremediation potential of thlaspi caerulescens is not well understood. we investigated the effect of soil ph and cd concentration on plant cd uptake on one soil type, and the variation in cd uptake using a range of field contaminated soils. on soils with total cd concentrations of 0.6-3.7 mg kg(-1), t. caerulescens (the ganges ecotype) produced greater biomass in the ph range 5.1-7.6 than at ph 4.4. the highest plant cd concentration (236 mg kg(-1 ... | 2006 | 15998562 |
| fixation of metals in soil constituents and potential remobilization by hyperaccumulating and non-hyperaccumulating plants: results from an isotopic dilution study. | in this study isotopic dilution methods were used to investigate the hypothesis that access to metals associated with specific chemical components in the soil that are not available to non-accumulator species could be involved in hyperaccumulation. the hyperaccumulator thlaspi caerulescens and a non-accumulator species, brassica napus, were grown in cd and zn enriched soil components calcite, goethite, charcoal and cryptomelane. the metal enriched components were aged to allow transformation of ... | 2006 | 16457917 |
| phytoextraction potential of the nickel hyperaccumulators leptoplax emarginata and bornmuellera tymphaea. | leptoplax emarginata and bornmuellera tymphaea are nickel hyperaccumulators of the brassicaceae family endemic to serpentine soils in greece. the aims of this work were to compare the growth and uptake behavior of these plants with the ni hyperaccumulator species thlaspi caerulescens and alyssum murale, and to evaluate their effect on soil ni availability. plants were grown for 3 mo on three soils that differ in ni availability. ni availability in soils was measuredby isotopic exchange kinetics ... | 2005 | 16463544 |
| a comparison of phytoremediation capability of selected plant species for given trace elements. | in our experiment, as, cd, pb, and zn remediation possibilities on medium contaminated soil were investigated. seven plant species with a different trace element accumulation capacity and remediation potential were compared. we found good accumulation capabilities and remediation effectiveness of salix dasyclados similar to studied hyperaccumulators (arabidopsis halleri and thlaspi caerulescens). we have noticed better remediation capability in willow compared to poplar for most of the elements ... | 2006 | 16516363 |
| construction of a genetic linkage map of thlaspi caerulescens and quantitative trait loci analysis of zinc accumulation. | zinc (zn) hyperaccumulation seems to be a constitutive species-level trait in thlaspi caerulescens. when compared under conditions of equal zn availability, considerable variation in the degree of hyperaccumulation is observed among accessions originating from different soil types. this variation offers an excellent opportunity for further dissection of the genetics of this trait. a t. caerulescens intraspecific cross was made between a plant from a nonmetallicolous accession [lellingen (le)], c ... | 2006 | 16539600 |
| phytoextraction of cadmium and zinc from arable soils amended with sewage sludge using thlaspi caerulescens: development of a predictive model. | the objectives of this study were to assess the potential for using thlaspi caerulescens as a phytoextraction plant and develop a user-advice model, which can predict the frequency of phytoextraction operation required under prescribed conditions. pot and field trials were conducted using soil collected from a dedicated sewage sludge disposal facility. soil amendments (sulphuric acid, potassium chloride and edta) intended to increase cd solubility were also tested. predictive models of cd and zn ... | 2007 | 17379365 |
| a comparison of the thlaspi caerulescens and thlaspi arvense shoot transcriptomes. | whole-genome transcriptome profiling is revealing how biological systems are regulated at the transcriptional level. this study reports the development of a robust method to profile and compare the transcriptomes of two nonmodel plant species, thlaspi caerulescens, a zinc (zn) hyperaccumulator, and thlaspi arvense, a nonhyperaccumulator, using affymetrix arabidopsis thaliana ath1-121501 genechip arrays (affymetrix, santa clara, ca, usa). transcript abundance was quantified in the shoots of agar- ... | 2006 | 16608451 |
| the heavy metal hyperaccumulator thlaspi caerulescens expresses many species-specific genes, as identified by comparative expressed sequence tag analysis. | thlaspi caerulescens is a natural zinc (zn), cadmium (cd) and nickel (ni) hyperaccumulator and an emerging plant model species to study heavy metal hyperaccumulation and tolerance. this paper describes the analysis of the first expressed sequence tag (est) collection from t. caerulescens. this collection is a new resource to unravel the molecular basis of plant metal homeostasis, tolerance and hyperaccumulation. in total, 4289 ests were generated originating from zn-exposed root and shoot tissue ... | 2006 | 16684236 |
| multivariate analysis of protein profiles of metal hyperaccumulator thlaspi caerulescens accessions. | thlaspi caerulescens is increasingly acknowledged as one of the best models for studying metal hyperaccumulation in plants. in order to study the mechanisms underlying metal hyperaccumulation, we used proteomic profiling to identify differences in protein intensities among three t. caerulescens accessions with pronounced differences in tolerance, uptake and root to shoot translocation of zn and cd. proteins were separated using two-dimensional electrophoresis and stained with sypro orange. inten ... | 2006 | 16691554 |
| qtl analysis of cadmium and zinc accumulation in the heavy metal hyperaccumulator thlaspi caerulescens. | thlaspi caerulescens (tc; 2n = 14) is a natural zn, cd and ni hyperaccumulator species belonging to the brassicaceae family. it shares 88% dna identity in the coding regions with arabidopsis thaliana (at) (rigola et al. 2006). although the physiology of heavy metal (hyper)accumulation has been intensively studied, the molecular genetics are still largely unexplored. we address this topic by constructing a genetic map based on aflp markers and expressed sequence tags (ests). to establish a geneti ... | 2006 | 16850314 |
| gene polymorphisms for elucidating the genetic structure of the heavy-metal hyperaccumulating trait in thlaspi caerulescens and their cross-genera amplification in brassicaceae. | genetic polymorphism was investigated in thlaspi caerulescens j. & c. presl at 15 gene regions, of which seven have been identified to putatively play a role in heavy-metal tolerance or hyperaccumulation. single nucleotide and length polymorphisms were assessed at four cleaved amplified polymorphic sequences (caps) and 11 simple sequence repeat (microsatellite) loci, respectively. the utility of these loci for genetic studies in t. caerulescens was measured among seven natural populations (135 i ... | 2006 | 16896532 |
| toxic metal accumulation, responses to exposure and mechanisms of tolerance in plants. | 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 acc ... | 2006 | 16914250 |
| response of thlaspi caerulescens to nitrogen, phosphorus and sulfur fertilisation. | the main limiting factor for cleaning-up contaminated soils with hyperaccumulator plants is the low production of aerial biomass and the number of successive crops needed to reach the objective of remediation. the aim of this study was to contribute to the determination of a fertilisation strategy to optimise soil metal phytoextraction by thlaspi caerulescens. a pot experiment was conducted on an agricultural soil and on a contaminated soil from the vicinity of a former pb/zn smelter. the nitrog ... | 2006 | 16924963 |
| thermal treatment of metal-enriched biomass produced from heavy metal phytoextraction. | phytoextraction is an environmentally sound method for cleaning up sites that are contaminated with toxic heavy metals. however, the method has been questioned because it produces a biomass-rich secondary waste containing the extracted metals. therefore, further treatment of this biomass is necessary. in this study, we investigated whether thermal treatment could be a feasible option for evaporatively separating metals from the plant residues. we used a laboratory scale reactor designed to simul ... | 2005 | 15926590 |
| transcription profiling of the metal-hyperaccumulator thlaspi caerulescens (j. & c. presl). | thlaspi caerulescens is a well-studied metal-hyperaccumulator of zinc, cadmium and nickel, belonging to the brassicaceae family. moreover it is one of the few hyperaccumulators that occur on different metalliferous soil types, as well as on nonmetalliferous soils. we are interested in the development of systems to improve phytoremediation of metal contaminated soils through improved metal-accumulation. about 1900 cdnas isolated from t. caerulescens roots were hybridized with reverse transcribed ... | 2005 | 15948586 |
| adaptative evolution of metallothionein 3 in the cd/zn hyperaccumulator thlaspi caerulescens. | laboratoire de physiologie et génétique moléculaire des plantes, université libre de bruxelles, campus plaine (cp 242) bd du triomphe, b-1050 brussels, belgium. | 2005 | 15948587 |
| cadmium leaching from micro-lysimeters planted with the hyperaccumulator thlaspi caerulescens: experimental findings and modeling. | 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 ... | 2006 | 17071874 |
| root-to-shoot long-distance circulation of nicotianamine and nicotianamine-nickel chelates in the metal hyperaccumulator thlaspi caerulescens. | plant metal hyperaccumulator species are widely used as models to unravel the heavy metal tolerance and hyperaccumulation mechanisms. thlaspi caerulescens is capable of tolerating and hyperaccumulating zn, cd, and ni. a search for factors involved in the cellular tolerance to ni, based on yeast screens, led to isolation of a cdna encoding a functional nicotianamine (na) synthase (nas). the t. caerulescens genome appears to contain a single copy of the nas gene named tcnas whose expression is res ... | 2006 | 17079698 |
| synthesis of low molecular weight thiols in response to cd exposure in thlaspi caerulescens. | in this study, we investigated the accumulation of phytochelatins (pcs) and other low molecular weight (lmw) thiols in response to cd exposure in two contrasting ecotypes differing in cd accumulation. using a root elongation test, we found that the highly accumulating ecotype ganges was more tolerant to cd than the low cd-accumulation ecotype prayon. l-buthionine-(s,r)-sulphoximine (bso), a potent inhibitor of the gamma-glutamylcysteine synthetase gamma-ecs) (an enzyme involved in the pc biosynt ... | 2006 | 17080963 |
| tcysl3, a member of the ysl gene family from the hyper-accumulator thlaspi caerulescens, encodes a nicotianamine-ni/fe transporter. | the two main features of plant hyper-accumulator species are the massive translocation of heavy metal ions to the aerial parts and their tolerance to such high metal concentrations. recently, several lines of evidence have indicated a role for nicotianamine (na) in metal homeostasis, through the chelation and transport of na-metal complexes. the function of transport of na-metal chelates, required for the loading and unloading of vessels, has been assigned to the yellow stripe 1 (ysl)-like famil ... | 2007 | 17144893 |
| life history variation in thlaspi caerulescens. | | 2007 | 17176388 |
| reaction norms of life history traits in response to zinc in thlaspi caerulescens from metalliferous and nonmetalliferous sites. | * we examined phenotypic plasticity of fitness components in response to zinc (zn) in the zn hyperaccumulator, thlaspi caerulescens. * two populations from zn-enriched soils (m) and two populations from normal soils (nm) were grown in pots at three zn concentrations (0, 1000 and 8000 mg kg(-1) zn), for an entire life cycle. growth, zn accumulation and fitness components were assessed. * based on vegetative growth, m and nm populations had similar zn tolerance at 1000 mg kg(-1) zn. however, repro ... | 2007 | 17176405 |
| 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. | * 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 co ... | 2007 | 17176406 |
| do metal-rich plants deter herbivores? a field test of the defence hypothesis. | some plant species growing on metalliferous soils are able to accumulate heavy metals in their shoots up to very high concentrations, but the selective advantage of this behaviour is still unknown. the most popular hypothesis, that metals protect plants against herbivores, has been tested several times in laboratory conditions, with contradictory results. we carried out the first large-scale test of the defence hypothesis in eight natural populations of the model zn hyperaccumulator thlaspi caer ... | 2007 | 17216212 |
| zinc in plants. | zinc (zn) is an essential component of thousands of proteins in plants, although it is toxic in excess. in this review, the dominant fluxes of zn in the soil-root-shoot continuum are described, including zn inputs to soils, the plant availability of soluble zn(2+) at the root surface, and plant uptake and accumulation of zn. knowledge of these fluxes can inform agronomic and genetic strategies to address the widespread problem of zn-limited crop growth. substantial within-species genetic variati ... | 2007 | 17286818 |
| selection of appropriate organic additives for enhancing zn and cd phytoextraction by hyperaccumulators. | chelant-enhanced phytoextraction is one of the most promising technologies to remove heavy metals from soil. the key of the technology is to choose suitable additives in combination with a suitable plant. in the present study, laboratory batch experiment of metal solubilization, cress seeds germination were undertaken to investigate the metal-mobilizing capability and the phytotoxicity of organic additives, including ethylene diamine triacetic acid (edta), citric acid, acetic acid, oxalic acid, ... | 2006 | 17294951 |
| testing of outstanding individuals of thlaspi caerulescens for cadmium phytoextraction. | thlaspi caerulescens is known to hyperaccumulate high quantities of cd with cd concentrations up to 3000 mg kg(-1) in some populations from south of france. however, within these populations, the cd concentrations can vary widely from plant to plant in a way that appears to be not entirely due to variations in soil cd. the aim of this work was to investigate the variability in the cd uptake ability of individual plants within a population and among seedlings grown from seeds from a single plant. ... | 2006 | 17305307 |
| a method for cellular localization of gene expression via quantitative in situ hybridization in plants. | a quantitative in situ hybridization technique (quantitative whole-mount in situ hybridization, qish) for plants is described. it employs direct hybridization of fluorescently labelled gene-specific oligonucleotides in large tissue pieces combined with optical sectioning. it dramatically increases the throughput compared with conventional antibody- and microtome-based in situ mrna hybridization methods, while simultaneously eliminating artefact-prone preparation steps that prevent reliable quant ... | 2007 | 17397510 |
| expression and functional analysis of metal transporter genes in two contrasting ecotypes of the hyperaccumulator thlaspi caerulescens. | zinc (zn) hyperaccumulation is a constitutive property of thlaspi caerulescens, whereas cadmium (cd) hyperaccumulation varies greatly among different ecotypes. the molecular basis of this variation is unknown. ecotypic differences in the sequences and expression of four representative zip family transporter genes were investigated. genome analysis indicated the presence of at least two closely related copies of the tcirt1 gene in both ganges (high cd accumulating) and prayon (low cd accumulating ... | 2007 | 17404382 |
| plant cd2+ and zn2+ status effects on root and shoot heavy metal accumulation in thlaspi caerulescens. | * in this study we address the impact of changes in plant heavy metal, (i.e. zinc (zn) and cadmium (cd)) status on metal accumulation in the zn/cd hyperaccumulator, thlaspi caerulescens. * thlaspi caerulescens plants were grown hydroponically on both high and low zn and cd regimes and whole-shoot and -root metal accumulation, and root (109)cd(2+) influx were determined. * high-zn-grown (500 microm zn) plants were found to be more cd-tolerant than plants grown in standard zn conditions (1 microm ... | 2007 | 17547666 |
| effects of chloride and co-contaminated zinc on cadmium accumulation within thlaspi caerulescens and durum wheat. | | 2007 | 17599229 |
| phytoextraction of metals from soils: how far from practice? | for most trace elements, the technique of phytoextraction needs significant improvements to become practically feasible. calculations for cd revealed that the amount of cd taken up by thlaspi caerulescens or salix spp. needs at least to be the double of the present amount to slightly decrease the cd concentration in the upper 0.5m of the soil within a period of 10 years. additionally, metals taken up by the plants might pose an important risk. alternatives as bioavailable contaminant stripping a ... | 2007 | 17604889 |
| cadmium-induced inhibition of photosynthesis and long-term acclimation to cadmium stress in the hyperaccumulator thlaspi caerulescens. | acclimation of hyperaccumulators to heavy metal-induced stress is crucial for phytoremediation and was investigated using the hyperaccumulator thlaspi caerulescens and the nonaccumulators t. fendleri and t. ochroleucum. spatially and spectrally resolved kinetics of in vivo absorbance and fluorescence were measured with a novel fluorescence kinetic microscope. at the beginning of growth on cadmium (cd), all species suffered from toxicity, but t. caerulescens subsequently recovered completely. dur ... | 2007 | 17688582 |
| using hyperaccumulator plants to phytoextract soil ni and cd. | two strategies of phytoextraction have been shown to have promise for practical soil remediation: domestication of natural hyperaccumulators and bioengineering plants with the genes that allow natural hyperaccumulators to achieve useful phytoextraction. because different elements have different value, some can be phytomined for profit and others can be phytoremediated at lower cost than soil removal and replacement. ni phytoextraction from contaminated or mineralized soils offers economic return ... | 2005 | 15948583 |
| an engineered plant that accumulates higher levels of heavy metals than thlaspi caerulescens, with yields of 100 times more biomass in mine soils. | nicotiana glauca transformed with tapcs1 was tested for its application in phytoremediation. when plantlets were grown in mine soils containing cu, zn, and pb (42, 2600, and 1500 mg kg(-1)) the plant showed high levels of accumulation especially of zn and pb. adult plants growing in mine soils containing different heavy metal concentrations showed a greater accumulation as well as an extension to a wider range of elements, including cd, ni and b. the overexpressed gene confers up to 9 and 36 tim ... | 2006 | 16337669 |
| cadmium hyperaccumulation and reproductive traits in natural thlaspi caerulescens populations. | during the last decade, the metal hyperaccumulating plants have attracted considerable attention because of their potential use in decontamination of heavy metal contaminated soils. however, in most species, little is known regarding the function, the ecological and the evolutionary significances of hyperaccumulation. in our study, we investigated the parameters influencing the cd concentration in plants as well as the biological implications of cd hyperaccumulation in nine natural populations o ... | 2006 | 16435270 |
| improved understanding of hyperaccumulation yields commercial phytoextraction and phytomining technologies. | this paper reviews progress in phytoextraction of soil elements and illustrates the key role of hyperaccumulator plant species in useful phytoextraction technologies. much research has focused on elements which are not practically phytoextracted (pb); on addition of chelating agents which cause unacceptable contaminant leaching and are cost prohibitive; and on plant species which offer no useful phytoextraction capability (e.g., brassica juncea czern). nickel phytoextraction by alyssum hyperaccu ... | 2007 | 17766822 |
| a native zn/cd pumping p(1b) atpase from natural overexpression in a hyperaccumulator plant. | 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 activ ... | 2007 | 17826738 |
| relationships of nicotianamine and other amino acids with nickel, zinc and iron in thlaspi hyperaccumulators. | experimental evidence suggests that nicotianamine (na) is involved in the complexation of metal ions in some metal-hyperaccumulating plants. closely-related nickel (ni)- and zinc (zn)-hyperaccumulating species were studied to determine whether a correlation exists between the ni and zn concentrations and na in foliar tissues. a liquid chromatography-mass spectrometry (lc-ms) procedure was developed to quantify the na and amino acid contents using the derivatizing agent 6-aminoquinolyl-n-hydroxys ... | 2007 | 17897323 |
| assessment of plants from the brassicaceae family as genetic models for the study of nickel and zinc hyperaccumulation. | we report on the second phase of a programme to select a relative of arabidopsis thaliana for use in large-scale molecular genetic studies of nickel (ni) and zinc (zn) hyperaccumulation. we also report on the relatedness among thlaspi caerulescens accessions and the utility of using o-acetyl-l-serine as a marker for ni and zn hyperaccumulation potential. twenty-seven new accessions of metal-accumulating species collected in the czech republic, france, greece, italy, slovenia and the usa during s ... | 2006 | 16995913 |
| large expression differences in genes for iron and zinc homeostasis, stress response, and lignin biosynthesis distinguish roots of arabidopsis thaliana and the related metal hyperaccumulator thlaspi caerulescens. | the micronutrient zinc has an essential role in physiological and metabolic processes in plants as a cofactor or structural element in 300 catalytic and noncatalytic proteins, but it is very toxic when available in elevated amounts. plants tightly regulate their internal zinc concentrations in a process called zinc homeostasis. the exceptional zinc hyperaccumulator species thlaspi caerulescens can accumulate up to 3% of zinc, but also high amounts of nickel and cadmium, without any sign of toxic ... | 2006 | 16998091 |
| isolation of zn-responsive genes from two accessions of the hyperaccumulator plant thlaspi caerulescens. | several populations with different metal tolerance, uptake and root-to-shoot transport are known for the metal hyperaccumulator plant thlaspi caerulescens. in this study, genes differentially expressed under various zn exposures were identified from the shoots of two t. caerulescens accessions (calaminous and non-calaminous) using fluorescent differential display rt-pcr. cdna fragments from 16 zn-responsive genes, including those encoding metallothionein (mt) type 2 and type 3, mrp-like transpor ... | 2007 | 17013613 |
| a novel wrky transcriptional factor from thlaspi caerulescens negatively regulates the osmotic stress tolerance of transgenic tobacco. | a novel member of the wrky gene family, designated tcwrky53, was isolated from a cadmium (cd)-treated thlaspi caerulescens cdna library by differential screening. wrky proteins specifically bind to w-boxes, which are found in the promoters of many genes involved in defense and response to environmental stress. tcwrky53 contains a 975-bp open reading frame encoding a putative protein of 324 amino acids. homology searches showed that tcwrky53 resembles similar wrky domain-containing proteins from ... | 2008 | 18183400 |
| soil microbial diversity as affected by the rhizosphere of the hyperaccumulator thlaspi caerulescens under natural conditions. | it is hypothesized that metal hyperaccumulator plants have specific rhizosphere conditions, potentially modifying the bioavailability of soil metals. this article aims to further the knowledge about the rhizosphere of the hyperaccumulator thlaspi caerulescens, focusing on its microflora isolated from metalliferous soils collected in situ where the plants grow naturally. we characterized the cultivable microbial communities isolated from the rhizosphere of one population of this ni hyperaccumulat ... | 2007 | 18246714 |
| does cadmium play a physiological role in the hyperaccumulator thlaspi caerulescens? | the southern french (ganges) ecotype of thlaspi caerulescens j & c presl is able to hyperaccumulate several thousand mg cd kg(-1) shoot dry weight without suffering from phytotoxicity. we investigated the effect of cd on growth and the activity of carbonic anhydrase (ca), a typical zn-requiring enzyme, of t. caerulescens in soil and hydroponic experiments. in one of the hydroponic experiments, t. caerulescens was compared to the non-accumulator thlaspi ferganense n. busch. in the soil experiment ... | 2008 | 18262587 |
| variation in root-to-shoot translocation of cadmium and zinc among different accessions of the hyperaccumulators thlaspi caerulescens and thlaspi praecox. | efficient root-to-shoot translocation is a key trait of the zinc/cadmium hyperaccumulators thlaspi caerulescens and thlaspi praecox, but the extent of variation among different accessions and the underlying mechanisms remain unclear. root-to-shoot translocation of cd and zn and apoplastic bypass flow were determined in 10 accessions of t. caerulescens and one of t. praecox, using radiolabels (109)cd and (65)zn. two contrasting accessions (pr and ga) of t. caerulescens were further characterized ... | 2008 | 18266619 |
| identification of nickel chelators in three hyperaccumulating plants: an x-ray spectroscopic study. | we have investigated the accumulation of nickel in a hyperaccumulating plant from the brassicacae family leptoplax emarginata (boiss.) o.e. schulz. two supplementary hyperaccumulating plants, which have been the subject of a high number of publications, alyssum murale waldst. & kit and thlaspi caerulescens j.&c. presl, and a nonaccumulating species aurinia saxatilis were also studied for reference. the plants were grown during 4 months in specific rhizoboxes with ni-bearing minerals as a source ... | 2008 | 18371995 |
| gene manipulation of a heavy metal hyperaccumulator species thlaspi caerulescens l. via agrobacterium-mediated transformation. | thlaspi caerulescens l. is well known as a zn/cd hyperaccumulator. the genetic manipulation of t. caerulescens through transgenic technology can modify plant features for use in phytoremediation. here, we describe the efficient transformation of t. caerulescens using agrobacterium tumefaciens strain eha105 harboring a binary vector pbi121 with the nptii gene as a selectable marker, the gus gene as a reporter and a foreign catalase gene. based on the optimal concentration of growth regulators, th ... | 2008 | 18427996 |
| investigating heavy-metal hyperaccumulation using thlaspi caerulescens as a model system. | metal-hyperaccumulating plant species are plants that are endemic to metalliferous soils and are able to tolerate and accumulate metals in their above-ground tissues to very high concentrations. one such hyperaccumulator, thlaspi caerulescens, has been widely studied for its remarkable properties to tolerate toxic levels of zinc (zn), cadmium (cd) and sometimes nickel (ni) in the soil, and accumulate these metals to very high levels in the shoot. the increased awareness regarding metal-hyperaccu ... | 2008 | 18440996 |
| plant response to heavy metal toxicity: comparative study between the hyperaccumulator thlaspi caerulescens (ecotype ganges) and nonaccumulator plants: lettuce, radish, and alfalfa. | 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 disso ... | 2008 | 18528911 |