Heavy Metals and Phytoremediation
Sung, Dong-Yul , Schroeder, Julian .
Luciferase-based genetic screening of cadmium response mutants.
In response to toxic heavy metals such as cadmium, plants induce changes in gene expression. Many of these changes in gene expression lead to activation of heavy metal detoxification mechanisms such as chelation of heavy metals and scavenging of heavy metal-mediated reactive oxygen species and aldehydes in plants. Biochemical and gene expression studies suggest that heavy metal inducible gene expression is mediated by metal stress-induced signaling pathways. However, despite the ability of some plants to hyperaccumulate heavy metals there is no genetic mutant isolated in plants that clearly identifies a heavy metal response pathway. To genetically elucidate a heavy metal mediated response pathway in Arabidopsis, initially microarray studies were pursued to identify strong cadmium inducible promoters. A strongly cadmium inducible promoter was selected to visually report a rapid transcriptional response of plants to cadmium exposure. With this promoter, cadmium-responsive luciferase reporter transgenic plants were generated and chemically mutagenized with EMS. Mutants showing abnormal luciferase activity in the presence or absence of cadmium were isolated and will be presented. One of the isolated mutants, 153-1 NR, has a mutation in a gene that encodes an important protein in heavy metal tolerance. Further mutants isolated in this genetic screen can provide insights into a pathway and mechanisms leading to gene expression changes and subsequent activation of heavy metal detoxification mechanisms.
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1 - University of California, San Diego, Division of Biological Sciences, 9500 Gilman Dr. MC0116, La Jolla, California, 92093-0116, USA
2 - University of California, San Diego, Division of Biological Sciences
Presentation Type: ASPB Minisymposium
Location: Continental C/Hilton
Date: Monday, July 9th, 2007
Time: 8:55 AM