Transcriptional responses of Arabidopsis thaliana plants to As (V) stress.
BACKGROUND
Arsenic is toxic to plants and a common environmental pollutant. There is a strong chemical similarity between arsenate [As (V)] and phosphate (Pi). Whole genome oligonucleotide microarrays were employed to investigate the transcriptional responses of Arabidopsis thaliana plants to As (V) stress.


RESULTS
Antioxidant-related genes (i.e. coding for superoxide dismutases and peroxidases) play prominent roles in response to arsenate. The microarray experiment revealed induction of chloroplast Cu/Zn superoxide dismutase (SOD) (at2g28190), Cu/Zn SOD (at1g08830), as well as an SOD copper chaperone (at1g12520). On the other hand, Fe SODs were strongly repressed in response to As (V) stress. Non-parametric rank product statistics were used to detect differentially expressed genes. Arsenate stress resulted in the repression of numerous genes known to be induced by phosphate starvation. These observations were confirmed with qRT-PCR and SOD activity assays.


CONCLUSIONS
Microarray data suggest that As (V) induces genes involved in response to oxidative stress and represses transcription of genes induced by phosphate starvation. This study implicates As (V) as a phosphate mimic in the cell by repressing genes normally induced when available phosphate is scarce. Most importantly, these data reveal that arsenate stress affects the expression of several genes with little or unknown biological functions, thereby providing new putative gene targets for future research.
Abercrombie
Jason M
JM
Department of Plant Sciences, University of Tennessee, 2431 Joe Johnson Blvd., Knoxville, TN 37996-4561, USA. jabercro@utk.edu
Halfhill
Matthew D
MD
Ranjan
Priya
P
Rao
Murali R
MR
Saxton
Arnold M
AM
Yuan
Joshua S
JS
Stewart
C Neal
CN
D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001149:Arsenates / Q000633:toxicity*; D016000:Cluster Analysis; D020869:Gene Expression Profiling; D017343:Genes, Plant; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress; D010710:Phosphates / Q000378:metabolism*; D018749:RNA, Plant / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D013482:Superoxide Dismutase / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
D029681:Arabidopsis Proteins; D001149:Arsenates; D010710:Phosphates; D018749:RNA, Plant; D014157:Transcription Factors; D013482:Superoxide Dismutase