Novel bacteriophages targeting wheat phyllosphere bacteria carry DNA modifications and single-strand breaks

Area of Science:

• Microbiology
• Virology
• Plant Science

Background:

• The phyllosphere microbiome significantly influences plant health, but effective control strategies are lacking.
• Bacteriophages (phages) offer a promising avenue for modulating bacterial communities in plant environments.
• Understanding phage diversity and function is crucial for developing microbiome management tools.

Purpose of the Study:

• To isolate and characterize novel bacteriophages targeting common wheat phyllosphere bacteria (Erwinia and Pseudomonas).
• To investigate genomic, phylogenetic, and morphological traits of these phages, including jumbo phages.
• To explore phage anti-defense systems, DNA modifications, and their prevalence in environmental samples.

Main Methods:

• Isolation and sequencing of eight novel phages targeting Erwinia and Pseudomonas strains.
• Genomic, phylogenetic, and morphological characterization of isolated phages.
• Nanopore sequencing to investigate DNA modifications and bioinformatics analysis of phage genomes and metagenomic data.

Main Results:

• Characterization of eight novel phages, including two jumbo phages, with proposals for four new viral genera.
• Identification of 13 motif-associated single-stranded DNA breaks in Pseudomonas phage Rembedalsseter, a feature potentially widespread in related phages.
• Discovery of close relatives to Erwinia jumbo-phage Kaldavass in diverse global metagenomes, indicating broad ecological distribution.

Conclusions:

• Novel phages targeting wheat phyllosphere bacteria have been identified, expanding the toolkit for microbiome manipulation.
• The study reveals potentially widespread DNA modification patterns in Pseudomonas phages, offering insights into phage-host interactions.
• Phage sequences found in environmental metagenomes highlight the interconnectedness of phage populations across geographical locations and environments.