DOI: 10.5281/zenodo.17809564
title: Cellulophaga baltica transcriptomics and proteomics - ISMEJ papers 2017 and 2018
title: Multiple mechanisms drive phage infection efficiency in nearly identical hosts
title: Regulation of infection efficiency in a globally abundant marine Bacteroidetes virus

description: Cellulophaga baltica strains #18 (i.e. Cba18) and NN016038 (i.e. Cba38) infected by phi38:1 - transcriptomes and proteomes.

Cba18 infected by phi38:1 and phi18:3 - transcriptomes and proteomes.

Datasets, genomes, and R scripts that are not already available with the publisher. Publications are The ISME Journal volume 11, pages284–295 (2017) and  The ISME Journal volume 12, pages1605–1618 (2018)
description: Phage–host interactions are critical to ecology, evolution, and biotechnology. Central to those is infection efficiency, which remains poorly understood, particularly in nature. Here we apply genome-wide transcriptomics and proteomics to investigate infection efficiency in nature’s own experiment: two nearly identical (genetically and physiologically) Bacteroidetes bacterial strains (host18 and host38) that are genetically intractable, but environmentally important, where phage infection efficiency varies. On host18, specialist phage phi18:3 infects efficiently, whereas generalist phi38:1 infects inefficiently. On host38, only phi38:1 infects, and efficiently. Overall, phi18:3 globally repressed host18’s transcriptome and proteome, expressed genes that likely evaded host restriction/modification (R/M) defenses and controlled its metabolism, and synchronized phage transcription with translation. In contrast, phi38:1 failed to repress host18’s transcriptome and proteome, did not evade host R/M defenses or express genes for metabolism control, did not synchronize transcripts with proteins and its protein abundances were likely targeted by host proteases. However, on host38, phi38:1 globally repressed host transcriptome and proteome, synchronized phage transcription with translation, and infected host38 efficiently. Together these findings reveal multiple infection inefficiencies. While this contrasts the single mechanisms often revealed in laboratory mutant studies, it likely better reflects the phage–host interaction dynamics that occur in nature.




 
description: Bacteria impact humans, industry and nature, but do so under viral constraints. Problematically, knowledge of viral infection efficiencies and outcomes derives from few model systems that over-represent efficient lytic infections and under-represent virus–host natural diversity. Here we sought to understand infection efficiency regulation in an emerging environmental Bacteroidetes–virus model system with markedly different outcomes on two genetically and physiologically nearly identical host strains. For this, we quantified bacterial virus (phage) and host DNA, transcripts and phage particles throughout both infections. While phage transcriptomes were similar, transcriptional differences between hosts suggested host-derived regulation of infection efficiency. Specifically, the alternative host overexpressed DNA degradation genes and underexpressed translation genes, which seemingly targeted phage DNA particle production, as experiments revealed they were both significantly delayed (by >30 min) and reduced (by >50%) in the inefficient infection. This suggests phage failure to repress early alternative host expression and stress response allowed the host to respond against infection by delaying phage DNA replication and protein translation. Given that this phage type is ubiquitous and abundant in the global oceans and that variable viral infection efficiencies are central to dynamic ecosystems, these data provide a critically needed foundation for understanding and modeling viral infections in nature.