Investigating Bacteriophage Acb2-Mediated Suppression of Anti-Phage Defenses in Microbacterium foliorum
Faculty Mentor Information
Dr. Michael Thomas, Idaho State University
Presentation Date
7-15-2026
Abstract
Microbacterium foliorum NRRL B-24224, a Gram-positive bacterium used in ISU’s SEA-PHAGES program for its BSL-1 status, appears to encode a putative anti-phage defense system. Upon phage infection, the bacteria cell produces signaling molecules to activate effector proteins leading to cell death, preventing phage infection of the whole culture. Phages counter these defense systems with anti-CBASS proteins Acb1 and Acb2, as well as MazG-like nucleotide pyrophosphohydrolase, and other counter-defense genes. These phage genes degrade, sequester or deplete cyclic nucleotide signals, downregulating the activation of the defense system and preventing cell death. A putative Acb2 was previously identified in M. foliorum phage Statler. To investigate its role in CBASS-mediated defense, we will clone, express, and purify the Statler Acb2 protein and assess its effect on plaque formation by Stalter and a non-Acb2 phage KillerTomato with M. foliorum. We hypothesize that Acb2 will increase plaque formation for KillerTomato, supporting its role as a broad-acting CBASS antagonist.
Investigating Bacteriophage Acb2-Mediated Suppression of Anti-Phage Defenses in Microbacterium foliorum
Microbacterium foliorum NRRL B-24224, a Gram-positive bacterium used in ISU’s SEA-PHAGES program for its BSL-1 status, appears to encode a putative anti-phage defense system. Upon phage infection, the bacteria cell produces signaling molecules to activate effector proteins leading to cell death, preventing phage infection of the whole culture. Phages counter these defense systems with anti-CBASS proteins Acb1 and Acb2, as well as MazG-like nucleotide pyrophosphohydrolase, and other counter-defense genes. These phage genes degrade, sequester or deplete cyclic nucleotide signals, downregulating the activation of the defense system and preventing cell death. A putative Acb2 was previously identified in M. foliorum phage Statler. To investigate its role in CBASS-mediated defense, we will clone, express, and purify the Statler Acb2 protein and assess its effect on plaque formation by Stalter and a non-Acb2 phage KillerTomato with M. foliorum. We hypothesize that Acb2 will increase plaque formation for KillerTomato, supporting its role as a broad-acting CBASS antagonist.