A Comprehensive Study on the Host Range of Gordonia terrae Bacteriophages and an Analysis of Possible Genes Involved in the Process.

Ariel M Stean, Brody T Mispagel, Evie Barth, Bryttan A Adams, Nadiya L Al-Murrani, Katherine L Boston, Madeline L Dee, Taylor Ewer, Brianna M Goebel, Rachel E Meeker, Jordan J Messmer, Sabrena Munoz, Annabelle Tate, Martha Smith-Caldas

Bacteriophages are generally specific to their hosts because their tail fibers recognize specific receptors on host cells. In the discovery phase of the Phage Hunters course, 39 bacteriophages were isolated from soil samples using Gordonia terrae as the host. After achieving high-titer lysates, these phages were tested for their ability to infect two additional hosts: Gordonia lacunae and Gordonia rubripertincta. Our results indicate that six of these phages can infect all three hosts, five phages infect G. terrae and G. rubripertincta, and three infect G. terrae and G. lacunae. The DNA of four tested phages was sequenced, and their genomes were annotated. Archidore is a temperate phage belonging to the DW cluster and was unable to infect either of the tested Gordonia species. Blondies, belonging to the CT cluster, is a virulent phage that infects all three Gordonia species tested, with an EOP of 10⁻² on both G. rubripertincta and G. lacunae. FuegoCuervo, a virulent phage in the DE1 cluster, has an EOP of 10⁻³ in G. lacunae but does not infect G. rubripertincta. Towmatter, which infects the wild host and G. rubripertincta with an EOP of -2, is a temperate phage associated with the DL cluster. Although the specific genes responsible for a broad host range in bacteriophages have not been clearly identified, genes such as major tail protein, tail assembly chaperone, lysin A glycosyl, holin, and DNA methyltransferase are often cited in the literature. For instance, Blondies possesses three tail assembly chaperone proteins and one lysin A glycosyl, which assist in host-cell interactions, whereas the other phages have only one or two tail assembly chaperones and no lysin A glycosyl. While G. terrae is more closely related to G. lacunae, more of the studied phages were able to infect G. rubripertincta as an alternative host, suggesting significant plasticity in bacteriophage host range.