Herbicide-hunting bacteria

An atrazine-binding RNA molecule was used to engineer Escherichia coli that seek and destroy the herbicide atrazine, as presented in a study published online this week in Nature Chemical Biology. This finding presents a new, and potentially generalizable, approach for using synthetic biology to remediate hazardous chemicals in the environment and illustrates how bacteria can be reprogrammed to perform multiple complex tasks.

Atrazine is widely used as an herbicide and poses environmental and health challenges particularly in the freshwater supply. Using the bacteria's native capacity to find nutrients in the environment, Justin Gallivan and colleagues reprogrammed a common strain of E. coli to migrate toward and break down the herbicide. Through a combination of in vitro and in vivo RNA selection procedures, the scientists identified a synthetic riboswitch ― an RNA that responds to a small molecule ― that activates protein translation in response to atrazine and induces bacteria to migrate in the presence of the herbicide. By incorporating another gene from an atrazine catabolic pathway, these bacteria could then also degrade atrazine.