Linked Life Data

16845524

Source:http://linkedlifedata.com/resource/pubmed/id/16845524

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2006-12-15
pubmed:abstractText
Several Arabidopsis CAtion eXchangers (CAXs) encode tonoplast-localized transporters that appear to be major contributors to vacuolar accumulation/sequestration of cadmium (Cd(2+)), an undesirable pollutant ion that occurs in man largely as a result of dietary consumption of aerial tissues of food plants. But, ion-selectivity of individual CAX transporter types remains largely unknown. Here, we transformed Nicotiana tabacum with several CAX genes driven by the Cauliflower Mosaic Virus (CaMV) 35S promoter and monitored divalent cation transport in root-tonoplast vesicles from these plants in order to select particular CAX genes directing high Cd(2+) antiporter activity in root tonoplast. Comparison of seven different CAX genes indicated that all transported Cd(2+), Ca(2+), Zn(2+), and Mn(2+) to varying degrees, but that CAX4 and CAX2 had high Cd(2+) transport and selectivity in tonoplast vesicles. CAX4 driven by the CaMV 35S and FS3 [figwort mosaic virus (FMV)] promoters increased the magnitude and initial rate of Cd(2+)/H(+) exchange in root-tonoplast vesicles. Ion selectivity of transport in root-tonoplast vesicles isolated from FS3::CAX4-expressing plant lines having a range of gene expression was Cd(2+)>Zn(2+)>>Ca(2+)>>Mn(2+) and the ratios of maximal Cd(2+) (and Zn(2+)) versus maximal Ca(2+) and Mn(2+) transport were correlated with the levels of CAX4 expression. Root Cd accumulation in high CAX4 and CAX2 expressing lines was increased in seedlings grown with 0.02 muM Cd. These observations are consistent with a model in which expression of an Arabidopsis-gene-encoded, Cd(2+)-efficient antiporter in host plant roots results in greater root vacuole Cd(2+) transport activity, increased root Cd accumulation, and a shift in overall root tonoplast ion transport selectivity towards higher Cd(2+) selectivity. Results support a model in which certain CAX antiporters are somewhat more selective for particular divalent cations.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0032-0935
pubmed:author
pubmed:issnType
Print
pubmed:volume
225
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
403-11
pubmed:dateRevised
2007-12-3
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Enhanced Cd2+ -selective root-tonoplast-transport in tobaccos expressing Arabidopsis cation exchangers.
pubmed:affiliation
Department of Plant and Soil Sciences, Plant Biology Program, University of Kentucky, Lexington, KY 40546, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural