Escherichia Phage Ge15, NRG-P0073: Genomic Characterization and Host Range Analysis Against the ECOR Reference Library

Abstract

Background: Genomic sequencing and annotation, morphological characterization, and host range analyses of bacteriophage (phage) isolates are crucial to understanding each phage's unique set of properties and how they can be utilized as effective tools in medicine, environmental monitoring, biotechnology, and agriculture. In this study, we present the fully annotated genome of viral isolate Escherichia phage Ge15 (GenBank Accession No. PP359696.1), taxonomically identified as unclassified Tequatrovirus, and deposited into our strain collection as sample NRG-P0073. A host range analysis was performed against all 72 isolates of the E. coli Reference (ECOR) library and a selection of Escherichia coli K-12 single-gene knockouts from the Keio collection in an effort to identify the receptor-binding protein.

Materials and methods: Whole genome sequencing, de novo assembly, and evidence-driven annotation using the Center for Phage Technology's Galaxy and Apollo software were performed on NRG-P0073. Double-agar spot tests were performed against the ECOR library and nine E. coli K-12 knockouts from the Keio collection to evaluate both the permissive and adsorptive host ranges of the phage. Transmission electron microscopy was utilized to elucidate the phage morphology.

Results: NRG-P0073 was found to have a 170,913 bp genome, coding for 10 tRNAs, 14 terminators, 259 genes, 249 coding sequences, and a GC content of 35.5%. Double-agar spot tests revealed that NRG-P0073 could adsorb 33 of the 72 strains (45.8%), but only 15 of the 72 strains (20.8%) could complete replication to form distinguishable plaques. All nine of the E. coli K-12 single-gene knockout strains (100%) supported complete phage replication, suggesting that none of the nine evaluated receptors are solely responsible for facilitating the attachment of NRG-P0073 to the host surface.

Conclusions: This study presents novel and complete genomic data, characterization, and host range analyses for the newly characterized phage NRG-P0073. Further characterization and analysis are required, including the identification of the E. coli receptor-binding protein responsible for initial host recognition. This study provides a foundation for future studies to understand more about NRG-P0073 and provides data that can be utilized for future machine-learning studies of phages and their host interactions.

Keywords: ECOR library; Ge15; Keio collection; NRG-P0073; bacteriophage; host range; phage.