Glyphosate on my plate?! Detection and inactivation of Glyphosate using the soil bacterium Bacillus subtilis

Feeding the steadily increasing world population is a major task that heavily relies on the use of fertilizers and herbicides. Glyphosate is the most prominent example for a total-herbicide. Glyphosate has been the most used herbicide in the US for the past decades and its usage is still increasing. The herbicide has a bad reputation, as it is thought to be harmful to human health and its effect on the environment is controversially discussed. Several studies indicate that glyphosate could also pose a threat to the biodiversity on our planet. However, no real long-term studies have been carried out so far in this regard. The goal of our team is to approach the glyphosate controversy and to improve the knowledge about the impact of the herbicide on the physiology of a soil-dwelling organism. The Gram-positive model bacterium Bacillus subtilis is a soil-dwelling organism that perfectly suited to achieve our goal. Previously, it has been demonstrated that the growth of B. subtilis is strongly inhibited by glyphosate. At first, we have assessed the potential of B. subtilis to adapt to toxic levels of glyphosate at the genome level. We have successfully isolated several mutant strains of B. subtilis that tolerate high amounts of glyphosate. All mutants had inactivated a gene encoding a transporter that is involved in uptake of an essential building block. Thus, our initial work led to the first glyphosate transport system! Currently, we engineer B. subtilis for the detection and inactivation of glyphosate. The microbial reporter system to detect glyphosate is based on labelled bacteria that tolerate different amounts of glyphosate and compete against each other for survival. We also engineer the bacteria to inactivate glyphosate using a bacterial enzyme that covalently modifies the herbicide. Our human practice section is dedicated to the raise of awareness for glyphosate and microbial research, while simultaneously cooperating with other scientific labs to achieve our goal. In the end, our project will provide an updated view on the glyphosate controversy with new insights into the effects of the herbicide on the physiology of an environmentally relevant organism.

iGEM-Team Göttingen, Georg-August University Göttingen, Germany

Members: Rica Bremenkamp, Malte Holmer, Jonas Jennrich, Veronika Lutz, Janek Meißner, Lisa Schulz, Robert Warneke, Marie Wensien, Dennis Wicke
Supervisors: Prof. Dr. Jörg Stülke, PD Dr. Fabian M. Commichau