Biosensors for Environmental Contaminants

DESCRIPTION (provided by applicant): Soil lead presents a major environmental health hazard, particularly to children. Current methods of detecting soil lead are expensive and typically provide grid-based models of contamination with significant uncertainties about lead concentrations between sampling points. This SBIR Phase I project seeks to develop a turf grass biosensor that provides a low-cost, high-resolution vegetative map of lead concentrations in the underlying soil, thereby assisting hazard identification and remediation activities. The project takes advantage of a recently-discovered metal responsive promoter element in Brassica juncea linked to the B anthocyanin regulatory gene. Arabidopsis thaliana plants transformed with the promoter-reporter construct overexpress anthocyanin in the presence of lead ions, creating a visible (purple) indicator of metal accumulation. In Phase I, the sensitivity and specificity of this response will be tested in Arabidopsis, alone and in combination with transient phytoextraction agents such as citric acid that are currently used to increase lead uptake in plants for phytoremediation. Phase I activities will also include transforming turf grass with the promoter-reporter construct. In Phase II, the performance of the engineered turf grass will be characterized and demonstrated at a lead-contaminated site. Successful completion of the project should lay the foundation for an innovative, low-cost biosensing technique for soil lead that will allow homeowners, real estate developers and environmental professionals to detect and monitor health hazards of a widespread environmental contaminant. The technique should prove extremely useful not only in detecting contamination, but also in monitoring the effectiveness of phytoremediation activities using turf grass, monitoring levels of bioavailable lead, and detecting recontamination at cleaned sites from windborne dust or runoff. In addition, demonstration of turf grass as a biosensor for soil lead is expected to stimulate development of low-cost biosensing techniques for other environmental health hazards.