Padala, M. | bioRxiv Science

bioRxiv2026

Genome-wide overexpression screen of Pseudomonas putida phage Emajogi

Bacteriophage genomes contain large fractions of uncharacterized genes, motivating high-throughput functional screens to illuminate their roles in host interaction and cytotoxicity. Here, we performed a genome wide overexpression assay for a Pseudomonas putida KT2440 infecting phage, Emajogi, and identified eight cytotoxic genes that reduce host growth under both basal and induced expression. We show that these proteins are conserved across phages that infect a diverse set of hosts. The most cytotoxic gene identified was a hypothetical protein (gp18) with no predicted functional domains. Transcriptomic profiling revealed that overexpression of gp18 caused a pronounced metabolic remodeling of the cell, likely shifting cell resources to phage production. Overall, this genome wide screen provides information about phage genes that were previously unannotated that can support biotechnology and novel antimicrobial development.

microbiology↗

bioRxiv2026

HtPIP: High-Throughput Phage Isolation Platform increases diversity and reduces isolation time using multiple bacteria

Bacteriophages are ubiquitous in nature, but relatively few have been isolated and characterized compared to the number of bacterial strains. Phage biotechnology applications benefit from a diverse library of isolated phages to kill or transfer genetic material to a bacterium of interest. However, scaling phage discovery for diverse bacterial hosts can be time consuming and costly. We developed an approach to capture novel phages for multiple bacteria strains in parallel from an environmental sample using commercially available 0.2-micron filter plates. Using this High-throughput Phage Isolation Platform (HtPIP), we isolated twelve novel phages spanning nine diverse bacterial host genera. Eleven of the isolated phages define new phage species with nine also defining new genera. We show the HtPIP can discover both DNA and RNA phages; including a Tectiviridae infecting Pseudomonas putida mt-2 and a Leviviricetes infecting a Microbacterium isolate, which represents the first cultured RNA phage infecting a host outside of proteobacteria. Using a metagenomic approach, we demonstrate that the HtPIP captures a higher proportion of novel phages compared to traditional low-throughput methods.

microbiology↗