Expanding the marine virosphere using metagenomics

• Autores: Carolina Megumi Mizuno
• Directores de la Tesis: Francisco Rodríguez Valera (dir. tes.), Rohit Ghai (codir. tes.)
• Lectura: En la Universidad Miguel Hernández de Elche ( España ) en 2015
• Idioma: inglés
• Tribunal Calificador de la Tesis: Josep M. Gasol (presid.), Mario Mencía Caballero (secret.), Josefa Antón Botella (voc.), Mark J. Van Raaij (voc.), Bastiaan Elie Dutilh (voc.)
• Materias:
  • Ciencias de la vida
    • Microbiología
    • Virología
      • Bacteriófagos
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• Resumen

  • Viruses are the most abundant biological entities on Earth, estimated to be ten times more in number than their prokaryotic hosts. Even with far larger numbers, their total biomass is miniscule in comparison, making retrieval of their DNA from the environment the primary obstacle in studying uncultured viruses. Moreover, the vast majority of the viral world is also unknown owing to our inability to culture their hosts. The inherent complexity of natural viral communities together with the technical limitations of obtaining sufficient genomic material for sequencing often results in the retrieval of very small genomic fragments. Here, we have used cellular metagenomic fosmids as an alternative to recover complete genomes of uncultured viruses, effectively bypassing several longstanding bottlenecks. Using this approach, we described more than a thousand long viral genomic fragments, of which 208 were complete phage genomes. This effort alone has tripled the number of complete phage genomes available from the marine environment. We have also assessed new methods, using only genomic information, to link these uncultured viruses to their hosts. The presence of several concurrent viral genomes has revealed an amazing micro¿diversity and mosaicism within the marine viral community. The availability of simultaneous, closely related lineages, along with a metavirome from the same location allowed the identification of genomic and metaviromic islands within these genomes, showing a remarkable degree of clonal diversity. These new approaches not only have succeeded in providing a glimpse into the vast and diverse marine viral world by identifying numerous novel viral groups, but have also opened a route towards phage population genomics.