{"title":"Ecological and evolutionary dynamics of CRISPR-Cas systems in Clostridium botulinum: Insights from genome mining and comparative analysis","authors":"Naiymeh Sheykholeslami , Hamid Mirzaei , Yousef Nami , Jalil Khandaghi , Afshin Javadi","doi":"10.1016/j.meegid.2024.105638","DOIUrl":null,"url":null,"abstract":"<div><p>Understanding the prevalence and distribution of CRISPR-Cas systems across different strains can illuminate the ecological and evolutionary dynamics of <em>Clostridium botulinum</em> populations. In this study, we conducted genome mining to characterize the CRISPR-Cas systems of <em>C. botulinum</em> strains. Our analysis involved retrieving complete genome sequences of these strains and assessing the diversity, prevalence, and evolution of their CRISPR-Cas systems. Subsequently, we performed an analysis of homology in spacer sequences from identified CRISPR arrays to investigate and characterize the range of targeted phages and plasmids. Additionally, we investigated the evolutionary trajectory of <em>C. botulinum</em> strains under selective pressures from foreign invasive DNA. Our findings revealed that 306 strains possessed complete CRISPR-Cas structures, comprising 58% of the studied <em>C. botulinum</em> strains. Secondary structure prediction of consensus repeats indicated that subtype II-C, with longer stems compared to subtypes I<img>D and I<img>B, tended to form more stable RNA secondary structures. Moreover, protospacer motif analysis demonstrated that strains with subtype I<img>B CRISPR-Cas systems exhibited 5′-CGG-3′, 5′-CC-3′, and 5′-CAT-3′ motifs in the 3′ flanking regions of protospacers. The diversity observed in CRISPR-Cas systems indicated their classification into subtypes I<img>B, I<img>D, II-C, III-B, and III-D. Furthermore, our results showed that systems with subtype I<img>D and III-D frequently harbored similar spacer patterns. Moreover, analysis of spacer sequences homology with phage and prophage genomes highlighted the specific activities exhibited by subtype I<img>B and III-B against phages and plasmids, providing valuable insights into the functional specialization within these systems.</p></div>","PeriodicalId":54986,"journal":{"name":"Infection Genetics and Evolution","volume":"123 ","pages":"Article 105638"},"PeriodicalIF":2.6000,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1567134824000893/pdfft?md5=85d8f5ba2afb6494ab5dc8b9ea3fe7e0&pid=1-s2.0-S1567134824000893-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Infection Genetics and Evolution","FirstCategoryId":"3","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1567134824000893","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"INFECTIOUS DISEASES","Score":null,"Total":0}
引用次数: 0
Abstract
Understanding the prevalence and distribution of CRISPR-Cas systems across different strains can illuminate the ecological and evolutionary dynamics of Clostridium botulinum populations. In this study, we conducted genome mining to characterize the CRISPR-Cas systems of C. botulinum strains. Our analysis involved retrieving complete genome sequences of these strains and assessing the diversity, prevalence, and evolution of their CRISPR-Cas systems. Subsequently, we performed an analysis of homology in spacer sequences from identified CRISPR arrays to investigate and characterize the range of targeted phages and plasmids. Additionally, we investigated the evolutionary trajectory of C. botulinum strains under selective pressures from foreign invasive DNA. Our findings revealed that 306 strains possessed complete CRISPR-Cas structures, comprising 58% of the studied C. botulinum strains. Secondary structure prediction of consensus repeats indicated that subtype II-C, with longer stems compared to subtypes ID and IB, tended to form more stable RNA secondary structures. Moreover, protospacer motif analysis demonstrated that strains with subtype IB CRISPR-Cas systems exhibited 5′-CGG-3′, 5′-CC-3′, and 5′-CAT-3′ motifs in the 3′ flanking regions of protospacers. The diversity observed in CRISPR-Cas systems indicated their classification into subtypes IB, ID, II-C, III-B, and III-D. Furthermore, our results showed that systems with subtype ID and III-D frequently harbored similar spacer patterns. Moreover, analysis of spacer sequences homology with phage and prophage genomes highlighted the specific activities exhibited by subtype IB and III-B against phages and plasmids, providing valuable insights into the functional specialization within these systems.
期刊介绍：
(aka Journal of Molecular Epidemiology and Evolutionary Genetics of Infectious Diseases -- MEEGID)
Infectious diseases constitute one of the main challenges to medical science in the coming century. The impressive development of molecular megatechnologies and of bioinformatics have greatly increased our knowledge of the evolution, transmission and pathogenicity of infectious diseases. Research has shown that host susceptibility to many infectious diseases has a genetic basis. Furthermore, much is now known on the molecular epidemiology, evolution and virulence of pathogenic agents, as well as their resistance to drugs, vaccines, and antibiotics. Equally, research on the genetics of disease vectors has greatly improved our understanding of their systematics, has increased our capacity to identify target populations for control or intervention, and has provided detailed information on the mechanisms of insecticide resistance.
However, the genetics and evolutionary biology of hosts, pathogens and vectors have tended to develop as three separate fields of research. This artificial compartmentalisation is of concern due to our growing appreciation of the strong co-evolutionary interactions among hosts, pathogens and vectors.
Infection, Genetics and Evolution and its companion congress [MEEGID](http://www.meegidconference.com/) (for Molecular Epidemiology and Evolutionary Genetics of Infectious Diseases) are the main forum acting for the cross-fertilization between evolutionary science and biomedical research on infectious diseases.
Infection, Genetics and Evolution is the only journal that welcomes articles dealing with the genetics and evolutionary biology of hosts, pathogens and vectors, and coevolution processes among them in relation to infection and disease manifestation. All infectious models enter the scope of the journal, including pathogens of humans, animals and plants, either parasites, fungi, bacteria, viruses or prions. The journal welcomes articles dealing with genetics, population genetics, genomics, postgenomics, gene expression, evolutionary biology, population dynamics, mathematical modeling and bioinformatics. We also provide many author benefits, such as free PDFs, a liberal copyright policy, special discounts on Elsevier publications and much more. Please click here for more information on our author services .
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