Browsing by Subject "Phages"

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Antiviral defense systems in the rumen microbiome
(2025) Sáenz, Johan S.; Rios-Galicia, Bibiana; Seifert, Jana
The continuous interaction between phages and their respective hosts has resulted in the evolution of multiple bacterial immune mechanisms. However, the diversity and prevalence of antiviral defense systems in complex communities are still unknown. We therefore investigated the diversity and abundance of viral defense systems in 3,038 high-quality bacterial and archaeal genomes from the rumen. In total, 14,241 defense systems and 31,948 antiviral-related genes were identified. Those genes represented 114 unique system types grouped into 49 families. We observed a high prevalence of defense systems in the genomes. However, the number of defense systems, defense system families, and system density varied widely from genome to genome. Additionally, the number of defense system per genome correlated positively with the number of defense system families and the genome size. Restriction modification, Abi, and cas system families were the most common, but many rare systems were present in only 1% of the genomes. Antiviral defense systems are prevalent and diverse in the rumen, but only a few are dominant, indicating that most systems are rarely present. However, the collection of systems throughout the rumen may represent a pool of mechanisms that can be shared by different members of the community and modulate the phage–host interaction.
Dynamic development of viral and bacterial diversity during grass silage preservation
(2023) Sáenz, Johan S.; Rios-Galicia, Bibiana; Rehkugler, Bianca; Seifert, Jana
Ensilaging is one of the most common feed preservation processes using lactic acid bacteria to stabilize feed and save feed quality. The silage bacterial community is well known but the role of the virome and its relationship with the bacterial community is scarce. In the present study, metagenomics and amplicon sequencing were used to describe the composition of the bacterial and viral community during a 40-day grass silage preservation. During the first two days, we observed a rapid decrease in the pH and a shift in the bacterial and viral composition. The diversity of the dominant virus operational taxonomic units (vOTUs) decreased throughout the preservation. The changes in the bacterial community resembled the predicted putative host of the recovered vOTUs during each sampling time. Only 10% of the total recovered vOTUs clustered with a reference genome. Different antiviral defense mechanisms were found across the recovered metagenome-assembled genomes (MAGs); however, only a history of bacteriophage infection with Lentilactobacillus and Levilactobacillus was observed. In addition, vOTUs harbored potential auxiliary metabolic genes related to carbohydrate metabolism, organic nitrogen, stress tolerance, and transport. Our data suggest that vOTUs are enriched during grass silage preservation, and they could have a role in the establishment of the bacterial community.