| 38 matches found in 14 documents. Search time: 0.185 seconds. |
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Score: 10.00 |
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| Title: Identification and characterization of maize and barley Lsi2-like silicon efflux transporters reveals a distinct silicon uptake system from that in rice .
| | Author: Mitani N Chiba Y Yamaji N Ma JF | | Journal: Plant Cell Citation: V : 21 P : 2133-42 Year: 2009 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub19574435 Accession (PMID): 19574435 | | Abstract: Silicon ( Si ) uptake has been extensively examined in rice ( Oryza sativa ) , but it is poorly understood in other gramineous crops .
We identified Low Silicon Rice 2 ( Lsi2 ) -like Si efflux transporters from two important gramineous crops : maize ( Zea mays ) and barley ( Hordeum vulgare ) .
Both maize and barley Lsi2 expressed in Xenopus laevis oocytes showed Si efflux transport activity .
Furthermore , barley Lsi2 was able to recover Si uptake in a rice mutant defective in Si efflux .
Maize and barley Lsi2 were only expressed in the roots .
Expression of maize and barley Lsi2 was downregulated in response to exogenously applied Si .
Moreover , there was a significant positive correlation between the ability of roots to absorb Si and the expression levels of Lsi2 in eight barley cultivars , suggesting that Lsi2 is a key Si transporter in barley .
Immunostaining showed that maize and barley Lsi2 localized only at the endodermis , with no polarity .
Protein gel blot analysis indicated that maize and barley Lsi2 localized on the plasma membrane .
The unique features of maize and barley Si influx and efflux transporters , including their cell-type specificity and the lack of polarity of their localization in Lsi2 , indicate that these crops have a different Si uptake system from that in rice .
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[ Sen. 7, subscore: 2.00 ]: Moreover , there was a significant positive correlation between the ability of roots to absorb Si and the expression levels of Lsi2 in eight barley cultivars , suggesting that Lsi2 is a key Si transporter in barley .
[ Sen. 2, subscore: 1.00 ]: We identified Low Silicon Rice 2 ( Lsi2 ) -like Si efflux transporters from two important gramineous crops : maize ( Zea mays ) and barley ( Hordeum vulgare ) .
[ Sen. 3, subscore: 1.00 ]: Both maize and barley Lsi2 expressed in Xenopus laevis oocytes showed Si efflux transport activity .
[ Sen. 4, subscore: 1.00 ]: Furthermore , barley Lsi2 was able to recover Si uptake in a rice mutant defective in Si efflux .
[ Sen. 5, subscore: 1.00 ]: Maize and barley Lsi2 were only expressed in the roots .
[ Sen. 6, subscore: 1.00 ]: Expression of maize and barley Lsi2 was downregulated in response to exogenously applied Si .
[ Sen. 8, subscore: 1.00 ]: Immunostaining showed that maize and barley Lsi2 localized only at the endodermis , with no polarity .
[ Sen. 9, subscore: 1.00 ]: Protein gel blot analysis indicated that maize and barley Lsi2 localized on the plasma membrane .
[ Sen. 10, subscore: 1.00 ]: The unique features of maize and barley Si influx and efflux transporters , including their cell-type specificity and the lack of polarity of their localization in Lsi2 , indicate that these crops have a different Si uptake system from that in rice .
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Score: 6.00 |
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| Title: Functions and transport of silicon in plants .
| | Author: Ma JF Yamaji N | | Journal: Cell Mol Life Sci Citation: V : P : Year: 2008 Type: Publisher | | Literature: oryza Field: abstract Doc ID: pub18560761 Accession (PMID): 18560761 | | Abstract: Silicon exerts beneficial effects on plant growth and production by alleviating both biotic and abiotic stresses including diseases , pests , lodging , drought , and nutrient imbalance .
Recently , two genes ( Lsi1 and Lsi2 ) encoding Si transporters have been identified from rice .
Lsi1 ( low silicon 1 ) belongs to a Nod26-like major intrinsic protein subfamily in aquaporin , while Lsi2 encodes a putative anion transporter .
Lsi1 is localized on the distal side of both exodermis and endodermis in rice roots , while Lsi2 is localized on the proximal side of the same cells .
Lsi1 shows influx transport activity for Si , while Lsi2 shows efflux transport activity .
Therefore , Lsi1 is responsible for transport of Si from the external solution to the root cells , whereas Lsi2 is an efflux transporter responsible for the transport of Si from the root cells to the apoplast Coupling of Lsi1 with Lsi2 is required for efficient uptake of Si in rice .
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[ Sen. 6, subscore: 2.00 ]: Therefore , Lsi1 is responsible for transport of Si from the external solution to the root cells , whereas Lsi2 is an efflux transporter responsible for the transport of Si from the root cells to the apoplast Coupling of Lsi1 with Lsi2 is required for efficient uptake of Si in rice .
[ Sen. 2, subscore: 1.00 ]: Recently , two genes ( Lsi1 and Lsi2 ) encoding Si transporters have been identified from rice .
[ Sen. 3, subscore: 1.00 ]: Lsi1 ( low silicon 1 ) belongs to a Nod26-like major intrinsic protein subfamily in aquaporin , while Lsi2 encodes a putative anion transporter .
[ Sen. 4, subscore: 1.00 ]: Lsi1 is localized on the distal side of both exodermis and endodermis in rice roots , while Lsi2 is localized on the proximal side of the same cells .
[ Sen. 5, subscore: 1.00 ]: Lsi1 shows influx transport activity for Si , while Lsi2 shows efflux transport activity .
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Score: 5.00 |
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| Title: High-resolution secondary ion mass spectrometry reveals the contrasting subcellular distribution of arsenic and silicon in rice roots .
| | Author: Moore KL Schroder M Wu Z Martin BG Hawes CR McGrath SP Hawkesford MJ Feng Ma J Zhao FJ Grovenor CR | | Journal: Plant Physiol Citation: V : 156 P : 913-24 Year: 2011 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub21490163 Accession (PMID): 21490163 | | Abstract: Rice ( Oryza sativa ) takes up arsenite mainly through the silicic acid transport pathway .
Understanding the uptake and sequestration of arsenic ( As ) into the rice plant is important for developing strategies to reduce As concentration in rice grain .
In this study , the cellular and subcellular distributions of As and silicon ( Si ) in rice roots were investigated using high-pressure freezing , high-resolution secondary ion mass spectrometry , and transmission electron microscopy .
Rice plants , both the lsi2 mutant lacking the Si/arsenite efflux transporter Lsi2 and its wild-type cultivar , with or without an iron plaque , were treated with arsenate or arsenite .
The formation of iron plaque on the root surface resulted in strong accumulation of As and phosphorous on the epidermis .
The lsi2 mutant showed stronger As accumulation in the endodermal vacuoles , where the Lsi2 transporter is located in the plasma membranes , than the wild-type line .
As also accumulated in the vacuoles of some xylem parenchyma cells and in some pericycle cells , particularly in the wild-type mature root zone .
Vacuolar accumulation of As is associated with sulfur , suggesting that As may be stored as arsenite-phytochelatin complexes .
Si was localized in the cell walls of the endodermal cells with little apparent effect of the Lsi2 mutation on its distribution .
This study reveals the vacuolar sequestration of As in rice roots and contrasting patterns of As and Si subcellular localization , despite both being transported across the plasma membranes by the same transporters .
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[ Sen. 4, subscore: 2.00 ]: Rice plants , both the lsi2 mutant lacking the Si/arsenite efflux transporter Lsi2 and its wild-type cultivar , with or without an iron plaque , were treated with arsenate or arsenite .
[ Sen. 6, subscore: 2.00 ]: The lsi2 mutant showed stronger As accumulation in the endodermal vacuoles , where the Lsi2 transporter is located in the plasma membranes , than the wild-type line .
[ Sen. 9, subscore: 1.00 ]: Si was localized in the cell walls of the endodermal cells with little apparent effect of the Lsi2 mutation on its distribution .
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Score: 4.00 |
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| Title: An efflux transporter of silicon in rice .
| | Author: Ma JF Yamaji N Mitani N Tamai K Konishi S Fujiwara T Katsuhara M Yano M | | Journal: Nature Citation: V : 448 P : 209-12 Year: 2007 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub17625566 Accession (PMID): 17625566 | | Abstract: Silicon is an important nutrient for the optimal growth and sustainable production of rice .
Rice accumulates up to 10% silicon in the shoot , and this high accumulation is required to protect the plant from multiple abiotic and biotic stresses .
A gene , Lsi1 , that encodes a silicon influx transporter has been identified in rice .
Here we describe a previously uncharacterized gene , low silicon rice 2 ( Lsi2 ) , which has no similarity to Lsi1 .
This gene is constitutively expressed in the roots .
The protein encoded by this gene is localized , like Lsi1 , on the plasma membrane of cells in both the exodermis and the endodermis , but in contrast to Lsi1 , which is localized on the distal side , Lsi2 is localized on the proximal side of the same cells .
Expression of Lsi2 in Xenopus oocytes did not result in influx transport activity for silicon , but preloading of the oocytes with silicon resulted in a release of silicon , indicating that Lsi2 is a silicon efflux transporter .
The identification of this silicon transporter revealed a unique mechanism of nutrient transport in plants : having an influx transporter on one side and an efflux transporter on the other side of the cell to permit the effective transcellular transport of the nutrients .
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[ Sen. 7, subscore: 2.00 ]: Expression of Lsi2 in Xenopus oocytes did not result in influx transport activity for silicon , but preloading of the oocytes with silicon resulted in a release of silicon , indicating that Lsi2 is a silicon efflux transporter .
[ Sen. 4, subscore: 1.00 ]: Here we describe a previously uncharacterized gene , low silicon rice 2 ( Lsi2 ) , which has no similarity to Lsi1 .
[ Sen. 6, subscore: 1.00 ]: The protein encoded by this gene is localized , like Lsi1 , on the plasma membrane of cells in both the exodermis and the endodermis , but in contrast to Lsi1 , which is localized on the distal side , Lsi2 is localized on the proximal side of the same cells .
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Score: 3.00 |
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| Title: Genotypic difference in silicon uptake and expression of silicon transporter genes in rice .
| | Author: Ma JF Yamaji N Tamai K Mitani N | | Journal: Plant Physiol Citation: V : 145 P : 919-24 Year: 2007 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub17905867 Accession (PMID): 17905867 | | Abstract: 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 K ( m ) value , whereas the V ( max ) 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 .
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[ Sen. 9, subscore: 2.00 ]: 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 .
[ Sen. 8, subscore: 1.00 ]: 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 .
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