The Experts below are selected from a list of 39123 Experts worldwide ranked by ideXlab platform
Malcolm J Hawkesford - One of the best experts on this subject based on the ideXlab platform.
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The sulphate Transporter gene family
Plant Nutrition, 2020Co-Authors: Malcolm J Hawkesford, Peter BuchnerAbstract:A gene family encoding sulphate Transporters has been identified. Sulphate Transporter Genes have been identified from many plant species, notably 13 homologues from Arabidopsis. Sequence analysis, functional studies and patterns of expression indicate the existence of sub-groups within the family. Expression analyses of members of the wheat gene family for sulphate Transporters are presented. This gene family is discussed in the context of whole-plant S-nutrition.
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expression and functional analysis of metal Transporter Genes in two contrasting ecotypes of the hyperaccumulator thlaspi caerulescens
Journal of Experimental Botany, 2007Co-Authors: Sonia Plaza, Peter Buchner, Kathryn L Tearall, Fangjie Zhao, S P Mcgrath, Malcolm J HawkesfordAbstract: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) ecotypes, with different copies being expressed in each, and, furthermore, the two Genes potentially encode different length transcripts. The predominant transcript in Prayon was truncated, missing sequence coding for the putative metal-binding site and the five C-terminal transmembrane helices. The two ecotypes were grown hydroponically 6Fe and Cd, and mRNA abundance determined for four ZIP Genes. The four ZIP Genes studied (TcIRT1, TcIRT2, TcZNT1 ,a ndTcZNT5) were expressed in roots only. TcIRT1 expression (full-length in Ganges, TcIRT11G; truncated in Prayon, TcIRT1-2P) was enhanced by Fe deficiency or by exposure to Cd. TcIRT2 expression was induced by Fe deficiency, but was unaffected by Cd exposure. TcZNT5-G showed greater expression in Prayon compared with Ganges. The functions of TcIRT1 from Ganges and Prayon and the Arabidopsis homologue were analysed by heterologous expression in yeast. All three IRT1 Genes were able to facilitate growth on low Fe concentrations. Cd sensitivity of yeast was conferred in the order AtIRT1>TcIRT11G>TcIRT1-2P (truncated). Cd uptake after 4 h was only detectable following complementation by AtIRT1. The results suggest that although TcIRT1-G may be involved in Cd hyperaccumulation in the Ganges ecotype of T. caerulescens, the Transporter expressed in yeast does not have an enhanced ability to transport Cd compared with AtIRT1. Therefore, the unique Cdaccumulating ability of the T. caerulescens Ganges ecotype must be due to the levels of expression of the protein or to other factors such as interacting proteins.
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regulation of sulfate uptake and expression of sulfate Transporter Genes in brassica oleracea as affected by atmospheric h2s and pedospheric sulfate nutrition
Plant Physiology, 2004Co-Authors: Peter Buchner, Elisabeth C E Stuiver, S Westerman, Markus Wirtz, Rudiger Hell, Malcolm J HawkesfordAbstract:Demand-driven signaling will contribute to regulation of sulfur acquisition and distribution within the plant. To investigate the regulatory mechanisms pedospheric sulfate and atmospheric H2S supply were manipulated in Brassica oleracea. Sulfate deprivation of B. oleracea seedlings induced a rapid increase of the sulfate uptake capacity by the roots, accompanied by an increased expression of Genes encoding specific sulfate Transporters in roots and other plant parts. More prolonged sulfate deprivation resulted in an altered shoot-root partitioning of biomass in favor of the root. B. oleracea was able to utilize atmospheric H2S as S-source; however, root proliferation and increased sulfate Transporter expression occurred as in S-deficient plants. It was evident that in B. oleracea there was a poor shoot to root signaling for the regulation of sulfate uptake and expression of the sulfate Transporters. cDNAs corresponding to 12 different sulfate Transporter Genes representing the complete gene family were isolated from Brassica napus and B. oleracea species. The sequence analysis classified the Brassica sulfate Transporter Genes into four different groups. The expression of the different sulfate Transporters showed a complex pattern of tissue specificity and regulation by sulfur nutritional status. The sulfate Transporter Genes of Groups 1, 2, and 4 were induced or up-regulated under sulfate deprivation, although the expression of Group 3 sulfate Transporters was not affected by the sulfate status. The significance of sulfate, thiols, and O-acetylserine as possible signal compounds in the regulation of the sulfate uptake and expression of the Transporter Genes is evaluated.
Jian Feng - One of the best experts on this subject based on the ideXlab platform.
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silicon reduces cadmium accumulation by suppressing expression of Transporter Genes involved in cadmium uptake and translocation in rice
Journal of Experimental Botany, 2017Co-Authors: Jian Feng, Naoki Yamaji, Ji Feng Shao, Ren Fang ShenAbstract:: Silicon (Si) alleviates cadmium (Cd) toxicity and accumulation in a number of plant species, but the exact molecular mechanisms responsible for this effect are still poorly understood. Here, we investigated the effect of Si on Cd toxicity and accumulation in rice (Oryza sativa) by using two mutants (lsi1 and lsi2) defective in Si uptake and their wild types (WTs). Root elongation was decreased with increasing external Cd concentrations in both WTs and mutants, but Si did not show an alleviative effect on Cd toxicity in all lines. By contrast, the Cd concentration in both the shoots and roots was decreased by Si in the WTs, but not in the mutants. Furthermore, Si supply resulted in a decreased Cd concentration in the root cell sap and xylem sap in the WTs, but not in the mutants. Pre-treatment with Si also decreased Cd accumulation in the WTs, but not in the mutants. Silicon slightly decreased Cd accumulation in the cell wall of the roots. The expression level of OsNramp5 and OsHMA2 was down-regulated by Si in the WTs, but not in the mutants. These results indicate that the Si-decreased Cd accumulation was caused by down-regulating Transporter Genes involved in Cd uptake and translocation in rice.
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overexpression of oshma3 enhances cd tolerance and expression of zn Transporter Genes in rice
Journal of Experimental Botany, 2014Co-Authors: Akimasa Sasaki, Naoki Yamaji, Jian FengAbstract:As a member of the heavy metal ATPase (HMA) family, OsHMA3 is a tonoplast-localized Transporter for Cd in the roots of rice (Oryza sativa). Overexpression of OsHMA3 selectively reduces Cd accumulation in the grain. Further characterization in the present study revealed that overexpression of OsHMA3 also enhances the tolerance to toxic Cd. The growth of both the roots and shoots was similar in the absence of Cd between an OsHMA3-overexpressed line and vector control, but the Cd-inhibited growth was significantly alleviated in the OsHMA3-overexpressed line. The overexpressed line showed higher Cd concentration in the roots, but lower Cd concentration in the shoots compared with the wild-type rice and vector control line, indicating that overexpression of OsHMA3 enhanced vacuolar sequestration of Cd in the roots. The Zn concentration in the roots of the OsHMA3-overexpressed line was constantly higher than that of vector control, but the Zn concentration in the shoots was similar between the overexpressed line and vector control. Five Transporter Genes belonging to the ZIP family were constitutively up-regulated in the OsHMA3-overexpressed line. These results suggest that shoot Zn level was maintained by up-regulating these Genes involved in the Zn uptake/translocation. Taken together, overexpression of OsHMA3 is an efficient way to reduce Cd accumulation in the grain and to enhance Cd tolerance in rice.
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genotypic difference in silicon uptake and expression of silicon Transporter Genes in rice
Plant Physiology, 2007Co-Authors: Jian Feng, Naoki Yamaji, Kazunori Tamai, Namiki MitaniAbstract:Rice (Oryza sativa) is a highly silicon (Si)-accumulating species that shows genotypic differences in Si accumulation. We investigated the physiological and molecular mechanisms involved in the genotypic difference in Si uptake between the japonica var. Nipponbare and the indica var. Kasalath. Both the Si concentration in the shoot and the Si uptake per root dry weight were higher in Nipponbare than in Kasalath grown in either soil or nutrient solution. The Si uptake by a single root was also higher in Nipponbare than in Kasalath. A kinetics study showed that Nipponbare and Kasalath had a similar Km value, whereas the Vmax was higher in Nipponbare. The expression of two Si Transporter Genes (Low silicon rice 1 [Lsi1] and Lsi2) investigated using real-time reverse transcription polymerase chain reaction revealed higher expression of both Genes in Nipponbare than in Kasalath. Immunostaining with Lsi1 and Lsi2 antibodies revealed a similar pattern of subcellular localization of these two Si Transporters in both varieties; Lsi1 and Lsi2 were localized at the distal and proximal sides, respectively, of both exodermis and endodermis of the roots. These results revealed that the genotypic difference in the Si accumulation results from the difference in abundance of Si Transporters in rice roots.
David J Eide - One of the best experts on this subject based on the ideXlab platform.
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structure function and regulation of a subfamily of mouse zinc Transporter Genes
Journal of Biological Chemistry, 2003Co-Authors: Jodi Dufnerbeattie, David J Eide, Joshua S Langmade, Fudi Wang, Glen K AndrewsAbstract:Abstract Zinc is an essential metal for all eukaryotes, and cells have evolved a complex system of proteins to maintain the precise balance of zinc uptake, intracellular storage, and efflux. In mammals, zinc uptake appears to be mediated by members of the Zrt/Irt-like protein (ZIP) superfamily of metal ion Transporters. Herein, we have studied a subfamily of zip Genes (zip1, zip2, and zip3) that is conserved in mice and humans. These eight-transmembrane domain proteins contain a conserved 12-amino acid signature sequence within the fourth transmembrane domain. All three of these mouse ZIP proteins function to specifically increase the uptake of zinc in transfected cultured cells, similar to the previously demonstrated functions of human ZIP1 and ZIP2 (Gaither, L. A., and Eide, D. J. (2000) J. Biol. Chem. 275, 5560–5564; Gaither, L. A., and Eide, D. J. (2001) J. Biol. Chem. 276, 22258–22264). No ZIP3 orthologs have been previously studied. Furthermore, this first systematic comparative study of the in vivo expression and dietary zinc regulation of this subfamily of zip Genes revealed that 1) zip1 mRNA is abundant in many mouse tissues, whereas zip2 and zip3 mRNAs are very rare or moderately rare, respectively, and tissue-restricted in their accumulation; and 2) unlike mouse metallothionein I and zip4 mRNAs (Dufner-Beattie, J., Wang, F., Kuo, Y.-M., Gitschier, J., Eide, D., and Andrews, G. K. (2003) J. Biol. Chem. 278, 33474–33481), the abundance of zip1, zip2, and zip3 mRNAs is not regulated by dietary zinc in the intestine and visceral endoderm, tissues involved in nutrient absorption. These studies suggest that all three of these ZIP proteins may play cell-specific roles in zinc homeostasis rather than primary roles in the acquisition of dietary zinc.
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identification of a family of zinc Transporter Genes from arabidopsis that respond to zinc deficiency
Proceedings of the National Academy of Sciences of the United States of America, 1998Co-Authors: Natasha Grotz, Erin L Connolly, Walter Park, Mary Lou Guerinot, David J EideAbstract:Millions of people worldwide suffer from nutritional imbalances of essential metals like zinc. These same metals, along with pollutants like cadmium and lead, contaminate soils at many sites around the world. In addition to posing a threat to human health, these metals can poison plants, livestock, and wildlife. Deciphering how metals are absorbed, transported, and incorporated as protein cofactors may help solve both of these problems. For example, edible plants could be engineered to serve as better dietary sources of metal nutrients, and other plant species could be tailored to remove metal ions from contaminated soils. We report here the cloning of the first zinc Transporter Genes from plants, the ZIP1, ZIP2, and ZIP3 Genes of Arabidopsis thaliana. Expression in yeast of these closely related Genes confers zinc uptake activities. In the plant, ZIP1 and ZIP3 are expressed in roots in response to zinc deficiency, suggesting that they transport zinc from the soil into the plant. Although expression of ZIP2 has not been detected, a fourth related Arabidopsis gene identified by genome sequencing, ZIP4, is induced in both shoots and roots of zinc-limited plants. Thus, ZIP4 may transport zinc intracellularly or between plant tissues. These ZIP proteins define a family of metal ion Transporters that are found in plants, protozoa, fungi, invertebrates, and vertebrates, making it now possible to address questions of metal ion accumulation and homeostasis in diverse organisms.
Peter Buchner - One of the best experts on this subject based on the ideXlab platform.
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The sulphate Transporter gene family
Plant Nutrition, 2020Co-Authors: Malcolm J Hawkesford, Peter BuchnerAbstract:A gene family encoding sulphate Transporters has been identified. Sulphate Transporter Genes have been identified from many plant species, notably 13 homologues from Arabidopsis. Sequence analysis, functional studies and patterns of expression indicate the existence of sub-groups within the family. Expression analyses of members of the wheat gene family for sulphate Transporters are presented. This gene family is discussed in the context of whole-plant S-nutrition.
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expression and functional analysis of metal Transporter Genes in two contrasting ecotypes of the hyperaccumulator thlaspi caerulescens
Journal of Experimental Botany, 2007Co-Authors: Sonia Plaza, Peter Buchner, Kathryn L Tearall, Fangjie Zhao, S P Mcgrath, Malcolm J HawkesfordAbstract: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) ecotypes, with different copies being expressed in each, and, furthermore, the two Genes potentially encode different length transcripts. The predominant transcript in Prayon was truncated, missing sequence coding for the putative metal-binding site and the five C-terminal transmembrane helices. The two ecotypes were grown hydroponically 6Fe and Cd, and mRNA abundance determined for four ZIP Genes. The four ZIP Genes studied (TcIRT1, TcIRT2, TcZNT1 ,a ndTcZNT5) were expressed in roots only. TcIRT1 expression (full-length in Ganges, TcIRT11G; truncated in Prayon, TcIRT1-2P) was enhanced by Fe deficiency or by exposure to Cd. TcIRT2 expression was induced by Fe deficiency, but was unaffected by Cd exposure. TcZNT5-G showed greater expression in Prayon compared with Ganges. The functions of TcIRT1 from Ganges and Prayon and the Arabidopsis homologue were analysed by heterologous expression in yeast. All three IRT1 Genes were able to facilitate growth on low Fe concentrations. Cd sensitivity of yeast was conferred in the order AtIRT1>TcIRT11G>TcIRT1-2P (truncated). Cd uptake after 4 h was only detectable following complementation by AtIRT1. The results suggest that although TcIRT1-G may be involved in Cd hyperaccumulation in the Ganges ecotype of T. caerulescens, the Transporter expressed in yeast does not have an enhanced ability to transport Cd compared with AtIRT1. Therefore, the unique Cdaccumulating ability of the T. caerulescens Ganges ecotype must be due to the levels of expression of the protein or to other factors such as interacting proteins.
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regulation of sulfate uptake and expression of sulfate Transporter Genes in brassica oleracea as affected by atmospheric h2s and pedospheric sulfate nutrition
Plant Physiology, 2004Co-Authors: Peter Buchner, Elisabeth C E Stuiver, S Westerman, Markus Wirtz, Rudiger Hell, Malcolm J HawkesfordAbstract:Demand-driven signaling will contribute to regulation of sulfur acquisition and distribution within the plant. To investigate the regulatory mechanisms pedospheric sulfate and atmospheric H2S supply were manipulated in Brassica oleracea. Sulfate deprivation of B. oleracea seedlings induced a rapid increase of the sulfate uptake capacity by the roots, accompanied by an increased expression of Genes encoding specific sulfate Transporters in roots and other plant parts. More prolonged sulfate deprivation resulted in an altered shoot-root partitioning of biomass in favor of the root. B. oleracea was able to utilize atmospheric H2S as S-source; however, root proliferation and increased sulfate Transporter expression occurred as in S-deficient plants. It was evident that in B. oleracea there was a poor shoot to root signaling for the regulation of sulfate uptake and expression of the sulfate Transporters. cDNAs corresponding to 12 different sulfate Transporter Genes representing the complete gene family were isolated from Brassica napus and B. oleracea species. The sequence analysis classified the Brassica sulfate Transporter Genes into four different groups. The expression of the different sulfate Transporters showed a complex pattern of tissue specificity and regulation by sulfur nutritional status. The sulfate Transporter Genes of Groups 1, 2, and 4 were induced or up-regulated under sulfate deprivation, although the expression of Group 3 sulfate Transporters was not affected by the sulfate status. The significance of sulfate, thiols, and O-acetylserine as possible signal compounds in the regulation of the sulfate uptake and expression of the Transporter Genes is evaluated.
Naoki Yamaji - One of the best experts on this subject based on the ideXlab platform.
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silicon reduces cadmium accumulation by suppressing expression of Transporter Genes involved in cadmium uptake and translocation in rice
Journal of Experimental Botany, 2017Co-Authors: Jian Feng, Naoki Yamaji, Ji Feng Shao, Ren Fang ShenAbstract:: Silicon (Si) alleviates cadmium (Cd) toxicity and accumulation in a number of plant species, but the exact molecular mechanisms responsible for this effect are still poorly understood. Here, we investigated the effect of Si on Cd toxicity and accumulation in rice (Oryza sativa) by using two mutants (lsi1 and lsi2) defective in Si uptake and their wild types (WTs). Root elongation was decreased with increasing external Cd concentrations in both WTs and mutants, but Si did not show an alleviative effect on Cd toxicity in all lines. By contrast, the Cd concentration in both the shoots and roots was decreased by Si in the WTs, but not in the mutants. Furthermore, Si supply resulted in a decreased Cd concentration in the root cell sap and xylem sap in the WTs, but not in the mutants. Pre-treatment with Si also decreased Cd accumulation in the WTs, but not in the mutants. Silicon slightly decreased Cd accumulation in the cell wall of the roots. The expression level of OsNramp5 and OsHMA2 was down-regulated by Si in the WTs, but not in the mutants. These results indicate that the Si-decreased Cd accumulation was caused by down-regulating Transporter Genes involved in Cd uptake and translocation in rice.
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overexpression of oshma3 enhances cd tolerance and expression of zn Transporter Genes in rice
Journal of Experimental Botany, 2014Co-Authors: Akimasa Sasaki, Naoki Yamaji, Jian FengAbstract:As a member of the heavy metal ATPase (HMA) family, OsHMA3 is a tonoplast-localized Transporter for Cd in the roots of rice (Oryza sativa). Overexpression of OsHMA3 selectively reduces Cd accumulation in the grain. Further characterization in the present study revealed that overexpression of OsHMA3 also enhances the tolerance to toxic Cd. The growth of both the roots and shoots was similar in the absence of Cd between an OsHMA3-overexpressed line and vector control, but the Cd-inhibited growth was significantly alleviated in the OsHMA3-overexpressed line. The overexpressed line showed higher Cd concentration in the roots, but lower Cd concentration in the shoots compared with the wild-type rice and vector control line, indicating that overexpression of OsHMA3 enhanced vacuolar sequestration of Cd in the roots. The Zn concentration in the roots of the OsHMA3-overexpressed line was constantly higher than that of vector control, but the Zn concentration in the shoots was similar between the overexpressed line and vector control. Five Transporter Genes belonging to the ZIP family were constitutively up-regulated in the OsHMA3-overexpressed line. These results suggest that shoot Zn level was maintained by up-regulating these Genes involved in the Zn uptake/translocation. Taken together, overexpression of OsHMA3 is an efficient way to reduce Cd accumulation in the grain and to enhance Cd tolerance in rice.
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genotypic difference in silicon uptake and expression of silicon Transporter Genes in rice
Plant Physiology, 2007Co-Authors: Jian Feng, Naoki Yamaji, Kazunori Tamai, Namiki MitaniAbstract:Rice (Oryza sativa) is a highly silicon (Si)-accumulating species that shows genotypic differences in Si accumulation. We investigated the physiological and molecular mechanisms involved in the genotypic difference in Si uptake between the japonica var. Nipponbare and the indica var. Kasalath. Both the Si concentration in the shoot and the Si uptake per root dry weight were higher in Nipponbare than in Kasalath grown in either soil or nutrient solution. The Si uptake by a single root was also higher in Nipponbare than in Kasalath. A kinetics study showed that Nipponbare and Kasalath had a similar Km value, whereas the Vmax was higher in Nipponbare. The expression of two Si Transporter Genes (Low silicon rice 1 [Lsi1] and Lsi2) investigated using real-time reverse transcription polymerase chain reaction revealed higher expression of both Genes in Nipponbare than in Kasalath. Immunostaining with Lsi1 and Lsi2 antibodies revealed a similar pattern of subcellular localization of these two Si Transporters in both varieties; Lsi1 and Lsi2 were localized at the distal and proximal sides, respectively, of both exodermis and endodermis of the roots. These results revealed that the genotypic difference in the Si accumulation results from the difference in abundance of Si Transporters in rice roots.
