Superfund Research Program

Arsenic Uptake, Transport and Storage in Plants

Project Leader: Mary L. Guerinot
Grant Number: P42ES007373
Funding Period: 2008-2021

Project-Specific Links

Final Progress Reports

Year:   2020  2013 

Rice, a staple food for over half the world’s population, represents a significant dietary source of arsenic, a human carcinogen. It is imperative that strategies to reduce grain arsenic are developed and identifying the mechanisms that enable arsenic to reach and accumulate within the rice grain is key to this endeavor. This past year the project has focused on gene discovery activities in the model plant Arabidopsis thaliana. Their genetic analysis showed that natural variation in arsenic toxicity in this species is explained by differences in expression of the NIP1;1 transporter. NIP1;1 showed highest expression in the outer layer of the root and its expression was downregulated when plants were exposed to arsenite. The research team’s gene expression studies have shown that there are distinct, cell type specific responses to arsenic exposure. Using this information, researchers hope to increase both efflux of arsenic out of the root as well as storage of arsenic in the root, thus preventing arsenic from reaching the seed. On August 31, 2020, Todd Warczak successfully defended his Ph.D. thesis entitled “Characterizing genetic factors that determine arsenic tolerance in plants and their contribution to arsenic detoxification in the roots.” His thesis improves the accuracy of current arsenic detoxification models by showing many genes have cell-type specific roles in the roots. This work also offers insights into how controlling NIP1;1 expression could help design crops that do not accumulate arsenic. Lastly, this thesis provides opportunities for further discovery of novel genes involved in arsenic tolerance.