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Brussowvirus SW13 Requires a Cell Surface-Associated Polysaccharide To Recognize Its Streptococcus thermophilus Host
Four bacteriophage-insensitive mutants (BIMs) of the dairy starter bacterium Streptococcus thermophilus UCCSt50 were isolated following challenge with Brussowvirus SW13. The BIMs displayed an altered sedimentation phenotype. Whole-genome sequencing and comparative genomic analysis of the BIMs uncove...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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American Society for Microbiology
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8752142/ https://www.ncbi.nlm.nih.gov/pubmed/34669424 http://dx.doi.org/10.1128/AEM.01723-21 |
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author | Lavelle, Katherine Sadovskaya, Irina Vinogradov, Evgeny Kelleher, Philip Lugli, Gabriele A. Ventura, Marco van Sinderen, Douwe Mahony, Jennifer |
author_facet | Lavelle, Katherine Sadovskaya, Irina Vinogradov, Evgeny Kelleher, Philip Lugli, Gabriele A. Ventura, Marco van Sinderen, Douwe Mahony, Jennifer |
author_sort | Lavelle, Katherine |
collection | PubMed |
description | Four bacteriophage-insensitive mutants (BIMs) of the dairy starter bacterium Streptococcus thermophilus UCCSt50 were isolated following challenge with Brussowvirus SW13. The BIMs displayed an altered sedimentation phenotype. Whole-genome sequencing and comparative genomic analysis of the BIMs uncovered mutations within a family 2 glycosyltransferase-encoding gene (orf06955(UCCSt50)) located within the variable region of the cell wall-associated rhamnose-glucose polymer (Rgp) biosynthesis locus (designated the rgp gene cluster here). Complementation of a representative BIM, S. thermophilus B1, with native orf06955(UCCSt50) restored phage sensitivity comparable to that of the parent strain. Detailed bioinformatic analysis of the gene product of orf06955(UCCSt50) identified it as a functional homolog of the Lactococcus lactis polysaccharide pellicle (PSP) initiator WpsA. Biochemical analysis of cell wall fractions of strains UCCSt50 and B1 determined that mutations within orf06955(UCCSt50) result in the loss of the side chain decoration from the Rgp backbone structure. Furthermore, it was demonstrated that the intact Rgp structure incorporating the side chain structure is essential for phage binding through fluorescence labeling studies. Overall, this study confirms that the rgp gene cluster of S. thermophilus encodes the biosynthetic machinery for a cell surface-associated polysaccharide that is essential for binding and subsequent infection by Brussowviruses, thus enhancing our understanding of S. thermophilus phage-host dynamics. IMPORTANCE Streptococcus thermophilus is an important starter culture bacterium in global dairy fermentation processes, where it is used for the production of various cheeses and yogurt. Bacteriophage predation of the species can result in substandard product quality and, in rare cases, complete fermentation collapse. To mitigate these risks, it is necessary to understand the phage-host interaction process, which commences with the recognition of, and adsorption to, specific host-encoded cell surface receptors by bacteriophage(s). As new groups of S. thermophilus phages are being discovered, the importance of underpinning the genomic elements that specify the surface receptor(s) is apparent. Our research identifies a single gene that is critical for the biosynthesis of a saccharidic moiety required for phage adsorption to its S. thermophilus host. The acquired knowledge provides novel insights into phage-host interactions for this economically important starter species. |
format | Online Article Text |
id | pubmed-8752142 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | American Society for Microbiology |
record_format | MEDLINE/PubMed |
spelling | pubmed-87521422022-01-24 Brussowvirus SW13 Requires a Cell Surface-Associated Polysaccharide To Recognize Its Streptococcus thermophilus Host Lavelle, Katherine Sadovskaya, Irina Vinogradov, Evgeny Kelleher, Philip Lugli, Gabriele A. Ventura, Marco van Sinderen, Douwe Mahony, Jennifer Appl Environ Microbiol Genetics and Molecular Biology Four bacteriophage-insensitive mutants (BIMs) of the dairy starter bacterium Streptococcus thermophilus UCCSt50 were isolated following challenge with Brussowvirus SW13. The BIMs displayed an altered sedimentation phenotype. Whole-genome sequencing and comparative genomic analysis of the BIMs uncovered mutations within a family 2 glycosyltransferase-encoding gene (orf06955(UCCSt50)) located within the variable region of the cell wall-associated rhamnose-glucose polymer (Rgp) biosynthesis locus (designated the rgp gene cluster here). Complementation of a representative BIM, S. thermophilus B1, with native orf06955(UCCSt50) restored phage sensitivity comparable to that of the parent strain. Detailed bioinformatic analysis of the gene product of orf06955(UCCSt50) identified it as a functional homolog of the Lactococcus lactis polysaccharide pellicle (PSP) initiator WpsA. Biochemical analysis of cell wall fractions of strains UCCSt50 and B1 determined that mutations within orf06955(UCCSt50) result in the loss of the side chain decoration from the Rgp backbone structure. Furthermore, it was demonstrated that the intact Rgp structure incorporating the side chain structure is essential for phage binding through fluorescence labeling studies. Overall, this study confirms that the rgp gene cluster of S. thermophilus encodes the biosynthetic machinery for a cell surface-associated polysaccharide that is essential for binding and subsequent infection by Brussowviruses, thus enhancing our understanding of S. thermophilus phage-host dynamics. IMPORTANCE Streptococcus thermophilus is an important starter culture bacterium in global dairy fermentation processes, where it is used for the production of various cheeses and yogurt. Bacteriophage predation of the species can result in substandard product quality and, in rare cases, complete fermentation collapse. To mitigate these risks, it is necessary to understand the phage-host interaction process, which commences with the recognition of, and adsorption to, specific host-encoded cell surface receptors by bacteriophage(s). As new groups of S. thermophilus phages are being discovered, the importance of underpinning the genomic elements that specify the surface receptor(s) is apparent. Our research identifies a single gene that is critical for the biosynthesis of a saccharidic moiety required for phage adsorption to its S. thermophilus host. The acquired knowledge provides novel insights into phage-host interactions for this economically important starter species. American Society for Microbiology 2022-01-11 /pmc/articles/PMC8752142/ /pubmed/34669424 http://dx.doi.org/10.1128/AEM.01723-21 Text en Copyright © 2022 Lavelle et al. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/) . |
spellingShingle | Genetics and Molecular Biology Lavelle, Katherine Sadovskaya, Irina Vinogradov, Evgeny Kelleher, Philip Lugli, Gabriele A. Ventura, Marco van Sinderen, Douwe Mahony, Jennifer Brussowvirus SW13 Requires a Cell Surface-Associated Polysaccharide To Recognize Its Streptococcus thermophilus Host |
title | Brussowvirus SW13 Requires a Cell Surface-Associated Polysaccharide To Recognize Its Streptococcus thermophilus Host |
title_full | Brussowvirus SW13 Requires a Cell Surface-Associated Polysaccharide To Recognize Its Streptococcus thermophilus Host |
title_fullStr | Brussowvirus SW13 Requires a Cell Surface-Associated Polysaccharide To Recognize Its Streptococcus thermophilus Host |
title_full_unstemmed | Brussowvirus SW13 Requires a Cell Surface-Associated Polysaccharide To Recognize Its Streptococcus thermophilus Host |
title_short | Brussowvirus SW13 Requires a Cell Surface-Associated Polysaccharide To Recognize Its Streptococcus thermophilus Host |
title_sort | brussowvirus sw13 requires a cell surface-associated polysaccharide to recognize its streptococcus thermophilus host |
topic | Genetics and Molecular Biology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8752142/ https://www.ncbi.nlm.nih.gov/pubmed/34669424 http://dx.doi.org/10.1128/AEM.01723-21 |
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