Plant Physiol. PAM Fluorometers & Gas Exchange
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Plant Physiology Preview
Published on March 31, 2006; 10.1104/pp.105.074815

This Article
Right arrow Full Text (Plant Physiology Preview (PDF))
Right arrow All Versions of this Article:
141/1/288    most recent
pp.105.074815v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Li, Y.
Right arrow Articles by Meagher, R. B.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Li, Y.
Right arrow Articles by Meagher, R. B.
Agricola
Right arrow Articles by Li, Y.
Right arrow Articles by Meagher, R. B.

Received November 29, 2005
Returned for revision February 6, 2006
Accepted March 6, 2006

The shoot-specific expression of gamma-glutamylcysteine synthetase directs the long-distance transport of thiol-peptides to roots conferring tolerance to mercury and arsenic

Yujing Li , Om Parkash Dankher , Laura Carreira , Aaron P. Smith , and Richard B. Meagher *

Department of Genetics, University of Georgia, Athens, GA 30602-7223; Current address: Emory School of Medicine, Department of Human Genetics, Emory University, Atlanta, GA 30345, email: yli29@emory.edu
Department of Genetics, University of Georgia, Athens, GA 30602-7223; Current address: Department of Plant, Soil, and Insect Sciences, University of Massachusetts, Amherst, MA 01002 email: parkash@psis.umass.edu
Applied PhytoGenetics, Inc. 110 Riverbend Road, Athens, GA30602, email: lcarreira@appliedphytogenetics.com
Department of Genetics, University of Georgia, Athens, GA 30602-7223; aps@uga.edu
Department of Genetics, University of Georgia, Athens, GA 30602-7223

* Corresponding author; email: meagher{at}uga.edu.

Thiol-peptides synthesized as intermediates in phytochelatin (PC) biosynthesis confer cellular tolerance to toxic elements like arsenic, mercury, and cadmium, but little is known about their long-distance transport between plant organs. A modified bacterial gamma-glutamylcysteine synthetase (ECS) gene, S1pt::ECS, was expressed in the shoots of the ECS-deficient, heavy metal sensitive, cad2-1 mutant of Arabidopsis thaliana. S1pt::ECS directed strong ECS protein expression in the shoots, but no ECS was detected in the roots of transgenic plant lines. The S1pt::ECS gene restored full mercury tolerance and partial cadmium tolerance to the mutant and enhanced arsenate tolerance significantly beyond wildtype levels. After arsenic treatment, the root concentrations of gamma-glutamylcysteine (EC), PC2, and PC3 peptides in a S1pt::ECS-complemented cad2-1 line increased 6- to 100-fold over the mutant levels and were equivalent to wildtype concentrations. The shoot and root levels of glutathione (GSH) were two- to five-fold above those in wildtype plants with or without treatment with toxicants. Thus, EC and perhaps GSH, are efficiently transported from shoots to roots. The possibility that EC or other PC pathway intermediates may act as carriers for the long-distance phloem transport and subsequent redistribution of thiol-reactive toxins and nutrients in plants is discussed.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
ASPB Publications PLANT PHYSIOLOGY THE PLANT CELL
Copyright © 2006 by the American Society of Plant Biologists