Overview of Concept

Our iGEM project for 2019 focuses on the plant pathogen Agrobacterium tumefaciens (also known as Rhizobium radiobacter), which causes millions of dollars of crop damage yearly. Agrobacterium senses the phenols and sugars that leak from plant wounds and causes tumors to develop at the wound site, which are usually called crown-gall tumors. While aspects of how this bacterium infects its host are well understood, we will answer two outstanding questions with our summer work: 1) How transferable is the Agrobacterium host signal recognition machinery to similar bacterial species? and 2) Can we capitalize on this understanding of host signal recognition to bioengineer a bacterium that out competes natural Agrobacterium and prevents pathogenesis by boosting the plant’s immune system? To answer the first question, we will use molecular biology techniques to shuttle the machinery necessary for Agrobacterium pathogenic into related species. This work will allow us to test our hypothesis that these receptor signals molecules are sufficient for host recognition. To address the second question, we have developed a strategy for creating a strain of Agrobacterium that responds to host signal but, instead of initiating pathogenesis, will stimulate plant defenses to prevent pathogenic Agrobacterium from infecting its host. This work related to the second question is the main body of our iGEM project.

Examples of Crown Gall Tumors in plants caused by Agrobacterium