Understanding microbial effects on soil and rhizosphere

Identifying types, and distributions, of nutrients found around plant roots is needed in order to better understand forces driving plant/microbe interactions. However, nutrients near the root are difficult to study: they are hard to extract from soil, they are readily used by microorganisms and thus rapidly disappear, and it is difficult to sample the root region without disrupting nutrient distributions. We have overcome some of these problems by constructing and deploying bacterial reporters which fluoresce, or produce light via the Lux proteins, when particular nutrients are present in the root/soil environment. The locations of fluorescing, or light emitting, bacteria indicate regions where particular nutrients are detected by the biosensing bacteria. Using this technology, nutrients and their locations in time and space can be observed around plant roots, and in soil. In addition, we are using microfluidics and light inducible gene expression to control bacterial exopolysaccharide systhesis and understand how it influences soil structure and water retention. This work is multidisciplinary and is being done in collaboration with Dr. Zoe Cardon at the Marine Biology Lab at Woods Hole, Dr. Leslie Shor, Dr. Yongku Cho and Dr. Jessica Furrer.