Our Story
Michigan State University is surrounded by agriculture and prides itself on its rich history. We gained inspiration from our local farmers who face the issue we are tackling. Our University also has a strong phage research community. Yearly MSU collects and samples the local Red Cedar River for its microbial diversity as well as phage diversity, a step we plan to utilize in creating our own biocontrol pipeline. With the support of our phage research community and the high-ranking agricultural and farming program MSU has, we quickly realized the challenge in demonstrating phage as a viable form of biocontrol fits the ideology of our school. Our school’s current involvement and the local community engagement in agriculture and the need of alternative treatments for plant pathogens ensured our team and community are ready to tackle the challenge of proving phage as a viable biocontrol.
The Problem
The United States CDC estimates 2.8 million drug-resistant infections resulting in 35,000 deaths yearly as a result1. Pseudomonads are amongst the most resistant to antimicrobials, not only in clinical settings, but equally in plant systems like P. syringae. P. syringae is a causative agent for multiple diseases including bacterial cankers and apical plant necrosis affecting nearly all major production agriculture crops. Despite the yearly rising numbers in drug-resistant infections, common treatments for P. syringae continue to include antimicrobial drugs. Drug-resistant microbes have sparked renewed interest in bacteriophage use in plant infections. Bacteriophages, or phages, are natural predators of bacteria using them as a host to reproduce and have been used as a plant pathogen biotcontrol. Phage has been used to treat P. syringae; however, application of phage on crops result in decreased phage viability due harsh leaf environmental conditions including UV and pH levels rendering them a less viable source of biocontrol.
Our Solution: Phage Capsid Modification!
Our team has isolated two novel P. syringae DC3000 tomato pv. phages from the Red Cedar River and tomato plant soil. We aim to characterize these phage and test environmental sensitivity for use as a biocontrol. We propose modifying the phage capsids through novel synthetic biology techniques of CRISPR and BRED to increase capsid rigidity. We will do so through the addition of SpyTag on the capsid with SpyCatcher amino acids to improve capsid protein interactions, increasing protection against variable climates on the plant surface to increase phage viability.
Our team's goal was to make P. syringae the example pathogen for a phage modifcation pipeline. Due to setbacks with material transfer rights, we adapted the project to do the same modification using an Ecoli phage, T7. We hope to demonstrate the ease of this framework so others can grow the library to include other pathogens.
Figure 2. Cartoon model depicting decorated phage capsid with flexible linker to SpyTag protein. Bottom model depicts decorated phage with SpyCatcher-GFP creating complex absorbing UV radiation producing fluorescence.