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The effect of cadmium on sulfate assimilation gene expression in Arabidopsis thaliana
Author(s) -
Sahi Jot Preet,
DeWitt Jane G.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.lb63-d
Subject(s) - sulfite reductase , cysteine , chemistry , phytochelatin , arabidopsis , sulfur metabolism , cadmium , biochemistry , arabidopsis thaliana , cysteine metabolism , reductase , enzyme , glutathione , gene , organic chemistry , mutant
Plants deal with heavy metal stress by synthesizing peptides called phytochelatins. Phytochelatins are cysteine‐rich peptides that chelate heavy metals such as cadmium. Cysteine is present in low concentrations in plants. It is likely that the synthesis of phytochelatins will increase the demand for cysteine. Our hypothesis is that metal tolerant plants are able to meet an increased demand for cysteine and wild type plants are not. The goal of our research is to find out how metal tolerant plants meet an increase in the need for cysteine imposed by cadmium. Is it by increasing the activity of the normal sulfate assimilation pathway or is there an alternate pathway by which cysteine is made available for phytochelatin production? Synthesis of cysteine begins when sulfate ions enter a cell using a transporter. Once inside, sulfate ion is adenylated in a reaction catalyzed by ATP sulfurylase (ATPS) converting it to adenosine 5′‐phosphosulphate (APS). APS then goes through two more reactions catalyzed by the enzymes APS reductase (APSR) and sulfite reductase (SiR) to produce sulfide ion. Sulfide then reacts with O ‐acetylserine (OAS) to form cysteine. In this project we focused on the expression of ATPS, APSR and SiR in wild type Arabidopsis thaliana grown under various cadmium concentrations using reverse transcriptase PCR and real time PCR. This research is supported by the NIH, MBRS SCORE S06 GM52588.