Endophyte-assisted phytoremediation of arsenic contaminated soils
R. TOURNAY (1), S. Doty (1), D. Sivitilli (1), T. DeLuca (1) (1) University of Washington, U.S.A.

Arsenic (As), a known carcinogen, is at elevated levels in many areas, and its toxicity impacts both human health and ecosystem integrity. Phytoremediation is a cost-effective technology using the natural ability of some plants to remediate pollutants, such as As, from the environment, but its efficiency is limited by slow uptake and phytotoxicity of the pollutants. Plants detoxify arsenate (AsV), the prevalent As species in aerobic conditions, via reduction to arsenite (AsIII), followed by efflux or complexation with phytochelatins and vacuolar sequestration. While various plant homologues of the yeast arsenate reductase (Acr2p) have been identified, the function of the ACR2-like genes in As metabolism in plants remains unresolved. Conversely, AsV to AsIII reduction in microbes is well characterized. Endophytes, microbes within plants, if efficient in the reduction of AsV to AsIII could complement the host plant’s detoxification mechanisms, and improve overall As tolerance. A highly As-tolerant endophyte strain (Pseudomonas sp.) was used to inoculate Arabidopsis seedlings on minimal media with up to 100 µM AsV. The inoculated Arabidopsis had significantly increased root length and biomass as compared to the mock-inoculated controls. The mechanisms by which the endophyte reduced the phytotoxic effects of As are under investigation. This endophyte-plant partnership could be used to improve the phytoremediation of As-contaminated soils.  

Abstract Number: P2-53
Session Type: Poster