Open AccessIncreased cysteine availability is essential for cadmium tolerance and accumulation in Arabidopsis thaliana
Author(s) -
DomínguezSolís José R.,
LópezMartín M. Carmen,
Ager Francisco J.,
Ynsa M. Dolores,
Romero Luis C.,
Gotor Cecilia
Publication year - 2004
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1111/j.1467-7652.2004.00092.x
Subject(s) - cadmium , trichome , cysteine , hyperaccumulator , glutathione , biology , arabidopsis thaliana , arabidopsis , phytochelatin , biosynthesis , biochemistry , botany , transformation (genetics) , phytoremediation , microbiology and biotechnology , mutant , chemistry , enzyme , gene , ecology , organic chemistry , contamination
Summary Employing genetic transformation using an Atcys‐3A cDNA construct expressing the cytosolic O ‐acetylserine(thiol)lyase (OASTL), we obtained two Arabidopsis lines with different capabilities for supplying cysteine under metal stress conditions. Lines 1‐2 and 10‐10, grown under standard conditions, showed similar levels of cysteine and glutathione (GSH) to those of the wild‐type. However, in the presence of cadmium, line 10‐10 showed significantly higher levels. The increased thiol content allowed line 10‐10 to survive under severe heavy metal stress conditions (up to 400 µ m of cadmium in the growth medium), and resulted in an accumulation of cadmium in the leaves to a level similar to that of metal hyperaccumulator plants. Investigation of the epidermal leaf surface clearly showed that most of the cadmium had accumulated in the trichomes. Furthermore, line 10‐10 was able to accumulate more cadmium in its trichomes than the wild‐type, whereas line 1‐2 showed a reduced capacity for cadmium accumulation. Our results suggest that an increased rate of cysteine biosynthesis is responsible for the enhanced cadmium tolerance and accumulation in trichome leaves. Thus, molecular engineering of the cysteine biosynthesis pathway, together with modification of the number of leaf trichomes, may have considerable potential in increasing heavy metal accumulation for phytoremediation purposes.