Viral diversity and host-virus interactions in the model crenarchaeon Sulfolobus islandicus
type: CreativeWork
description: Viruses are pervasive evolutionary forces and key players shaping natural populations. Our understanding of viral impact on host physiology however, is based on a few model systems that represent a small fraction of the life-history strategies employed by hosts or viruses across the three domains of life. The factors that define these host-virus coevolutionary dynamics are not easily approached in complex natural systems. Microbes and the viruses that infect them provide a framework to study these coevolutionary interactions because evolution can be observed in real time in systems that are experimentally tractable. Acidic hot springs serve as a model system to study these interactions in natural populations because they provide low-complexity and geographically isolated environments with a limited number of microbial hosts where viruses are the only known predator. Within these springs we find the hyperthermophilic crenarchaeon Sulfolobus islandicus which represents one of the few genetically tractable systems within the TACK (Thaumarchaeota, 'Aigarchaeota', Crenarchaeota and Korarchaeota) archaea. In this dissertation I focus on broadening our understanding of host-virus interactions in this system. In Chapter 2 we investigate the impact of SSV9 (Sulfolobus spindle - shaped virus 9) challenge on CRISPR immune and CRISPR deficient S. islandicus hosts and demonstrate that CRISPR-Cas immunity is active in S. islandicus against a naturally occurring virus. Surprisingly, we uncovered that SSV9 induces a population-wide dormancy response at a low multiplicity of infection (MOI) from which only cultures with CRISPR immunity were able to recover. Dormancy was independent of productive infection since challenge with UV inactivated SSV9 particles caused cultures to go dormant. Further, continuous exposure to inactivated particles, mimicking the continuous production of SSV9 particles in CRISPR deficient cultures, resulted in cell death. In Chapter 3 we investigate the cost …
abstract: Viruses are pervasive evolutionary forces and key players shaping natural populations. Our understanding of viral impact on host physiology however, is based on a few model systems that represent a small fraction of the life-history strategies employed by hosts or viruses across the three domains of life. The factors that define these host-virus coevolutionary dynamics are not easily approached in complex natural systems. Microbes and the viruses that infect them provide a framework to study these coevolutionary interactions because evolution can be observed in real time in systems that are experimentally tractable. Acidic hot springs serve as a model system to study these interactions in natural populations because they provide low-complexity and geographically isolated environments with a limited number of microbial hosts where viruses are the only known predator. Within these springs we find the hyperthermophilic crenarchaeon Sulfolobus islandicus which represents one of the few genetically tractable systems within the TACK (Thaumarchaeota, 'Aigarchaeota', Crenarchaeota and Korarchaeota) archaea. In this dissertation I focus on broadening our understanding of host-virus interactions in this system. In Chapter 2 we investigate the impact of SSV9 (Sulfolobus spindle - shaped virus 9) challenge on CRISPR immune and CRISPR deficient S. islandicus hosts and demonstrate that CRISPR-Cas immunity is active in S. islandicus against a naturally occurring virus. Surprisingly, we uncovered that SSV9 induces a population-wide dormancy response at a low multiplicity of infection (MOI) from which only cultures with CRISPR immunity were able to recover. Dormancy was independent of productive infection since challenge with UV inactivated SSV9 particles caused cultures to go dormant. Further, continuous exposure to inactivated particles, mimicking the continuous production of SSV9 particles in CRISPR deficient cultures, resulted in cell death. In Chapter 3 we investigate the cost …
author: Bautista Chavarriaga, Maria Alejandra
language: en
keywords: Sulfolobus islandicus, Host-virus interactions, Viral diversity
date published: 2016-07-07T21:17:39Z
date modified: 2026-07-22T22:26:34Z
provider: University of Illinois - Urbana-Champaign
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Illinois at Urbana-Champaign

PropertyValue
property ID: Handle
value: http://hdl.handle.net/2142/90921