Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2003-11-17
pubmed:abstractText
Selenium (Se) can be assimilated and volatilized via the sulfate assimilation pathway. Cystathionine-gamma-synthase (CGS) is thought to catalyze the synthesis of Se-cystathionine from Se-cysteine, the first step in the conversion of Se-cysteine to volatile dimethylselenide. Here the hypothesis was tested that CGS is a rate-limiting enzyme for Se volatilization. Cystathionine-gamma-synthase from Arabidopsis thaliana (L.) Heynh. was overexpressed in Indian mustard [ Brassica juncea (L.) Czern & Coss], and five transgenic CGS lines with up to 10-fold enhanced CGS levels were compared with wild-type Indian mustard with respect to Se volatilization, tolerance and accumulation. The CGS transgenics showed 2- to 3-fold higher Se volatilization rates than wild-type plants when supplied with selenate or selenite. Transgenic CGS plants contained 20-40% lower shoot Se levels and 50-70% lower root Se levels than the wild type when supplied with selenite. Furthermore, CGS seedlings were more tolerant to selenite than the wild type. There were no differences in Se accumulation or tolerance from selenate, in agreement with the earlier finding that selenate-to-selenite reduction is rate-limiting for selenate tolerance and accumulation. In conclusion, CGS appears to be a rate-limiting enzyme for Se volatilization. Overexpression of CGS offers a promising approach for the creation of plants with enhanced capacity to remove Se from contaminated sites in the form of low-toxic volatile dimethylselenide.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0032-0935
pubmed:author
pubmed:issnType
Print
pubmed:volume
218
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
71-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Overexpression of cystathionine-gamma-synthase enhances selenium volatilization in Brassica juncea.
pubmed:affiliation
Department of Biology, Colorado State University, Anatomy/Zoology Building, Fort Collins, CO 80523, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.