Superfund Research Program
Project Leader: Mark P. Elless
Grant Number: R42ES014976
Funding Period: Phase II: September 2009 – August 2011
The researchers working under this Small Business Technology Transfer project are developing a plant bioreporter for arsenic, a carcinogen that is widely dispersed in the environment and is one of the two most common contaminants at Superfund sites. Currently, extensive sampling and laboratory analysis of soil and water is often required to detect and monitor arsenic over large areas affected by activities such as pesticide use, mining, smelting, and construction with pressure-treated wood. The expense and inconvenience of such sampling restricts characterization and remediation of environmental health hazards caused by arsenic, indicating an urgent need for more costeffective approaches. An interdisciplinary solution to this problem is to create an arsenic phytosensor that combines microbial genes responsive to the presence of arsenic, with a green fluorescent protein (GFP) reporter, in a plant known to hyperaccumulate arsenic. When illuminated with ultraviolet light, the engineered plant would fluoresce green in the presence of arsenic, acting as an amplifying transducer of the environmental arsenic “signal” into visual wavelengths.
In Phase I, constructs using the well-characterized arsenic repressor (arsR) gene from E. coli were fused to the GFP gene and inserted into tobacco, with regenerated T2 plants tested for arsenic response. Transgenic tobacco plants having both the arsR and GFP genes appeared to show a doubling in GFP fluorescence following exposure to arsenic, suggesting the creation of a functioning arsenic phytosensors, without affecting the ability of these plants to accumulate arsenic in its leaves. In addition, efforts began in Phase I to transform Pteris vittata, a known hyperaccumulator of arsenic, with the arsR/GFP construct. In Phase II, transformation of Pteris vittata is being completed in order to develop an arsenic phytosensor that can be used for cleanup as well as detection of environmental arsenic. Laboratory and field testing of the fern and tobacco phytosensors are also being completed in Phase II. Edenspace Systems Corporation is partnering with Professor Neal Stewart, an international plant transformation expert at The University of Tennessee, to develop these arsenic phytosensors. Letters of support from the Army Corps of Engineers, Geosyntec Consultants, and Plantavit Cooperative attest to the strong need for such phytosensors to assist in soil arsenic remediation efforts. Benefits to customers of the new phytosensor technology include reducing environmental health hazards posed by arsenic, and assisting efforts to monitor and clean the environment. The project is leading to the development of innovative, cost-effective, real-time, solar-powered phytosensors to monitor water and soil quality, which could offer high spatial resolution, stand-off reporting, ready scaling to large treatment areas, and continuous in situ monitoring of bioavailable arsenic in government, industrial, commercial, agricultural and residential properties.