Abstract
Agrobacterium tumefaciens is a plant pathogen that causes crown gall disease, leading to the damage of agriculturally-important crops. As part of an effort to discover new phages that can potentially be used as biocontrol agents to prevent crown gall disease, we isolated and characterized phage Atu_ph07 from Sawyer Creek in Springfield, MO, using the virulent Agrobacterium tumefaciens strain C58 as a host. After surveying its host range, we found that Atu_ph07 exclusively infects Agrobacterium tumefaciens. Time-lapse microscopy of A. tumefaciens cells subjected to infection at a multiplicity of infection (MOI) of 10 with Atu_ph07 reveals that lysis occurs within 3 h. Transmission electron microscopy (TEM) of virions shows that Atu_ph07 has a typical Myoviridae morphology with an icosahedral head, long tail, and tail fibers. The sequenced genome of Atu_ph07 is 490 kbp, defining it as a jumbo phage. The Atu_ph07 genome contains 714 open reading frames (ORFs), including 390 ORFs with no discernable homologs in other lineages (ORFans), 214 predicted conserved hypothetical proteins with no assigned function, and 110 predicted proteins with a functional annotation based on similarity to conserved proteins. The proteins with predicted functional annotations share sequence similarity with proteins from bacteriophages and bacteria. The functionally annotated genes are predicted to encode DNA replication proteins, structural proteins, lysis proteins, proteins involved in nucleotide metabolism, and tRNAs. Characterization of the gene products reveals that Atu_ph07 encodes homologs of 16 T4 core proteins and is closely related to Rak2-like phages. Using ESI-MS/MS, the majority of predicted structural proteins could be experimentally confirmed and 112 additional virion-associated proteins were identified. The genomic characterization of Atu_ph07 suggests that this phage is lytic and the dynamics of Atu_ph07 interaction with its host indicate that this phage may be suitable for inclusion in a phage cocktail to be used as a biocontrol agent.
Highlights
Bacteriophages, or phages, are the most abundant biological entities on the planet (Clokie et al, 2011)
Agrobacterium tumefaciens strains were cultured in Lysogeny Broth (LB), with the exception of A. tumefaciens strain LBA4404, which was grown in yeast mannitol (YM) medium
Agrobacterium vitis was cultured using potato dextrose media (Difco), Rhizobium rhizogenes was grown in mannitol glutamate yeast (MGY) medium and Caulobacter crescentus was grown in peptone-yeast extract (PYE) medium (Poindexter, 1964)
Summary
Bacteriophages, or phages, are the most abundant biological entities on the planet (Clokie et al, 2011). Phages are viruses that infect bacteria, often causing lysis. Phagemediated host cell lysis of bacteria impacts environments both directly through release of dissolved organic carbon and micronutrients and indirectly by modulation of the microbial communities (Srinivasiah et al, 2008). Phages contribute to horizontal gene transfer and host cell evolution. The diversity and vast number of phage genes coupled with limited functional characterization results in the presence of many predicted proteins of unknown function (Hatfull, 2015). Since characterization of phages and their proteins will provide biological insights, some of which can be leveraged to address current challenges in medicine and agriculture, research on phage biology, phage-host interactions, and phage-derived enzymes has recently reemerged (Santos et al, 2018)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
