Crenarchaeal viruses of hot springs: Diversity, ecology and co-evolution

Abstract

Hot springs vary in temperature and pH, even within the same geological region. At temperatures above 68ÅC, eukaryotes are unable to survive, and the microbial communities become dominated by Bacteria, Archaea and viruses. As temperatures rise and pH levels decrease, Archaea dominate the communities with few Bacteria being present. It is these hot (> 80ÅC), acidic (pH < 3) springs from which most of our understanding of thermal viruses comes. This chapter will address what we know about the morphological and genetic diversity of the viruses from studies of viral isolates as well as the application of culture independent methods to hot springs. Additionally, it will address areas where we know relatively little, such as the ecological role of these viruses, areas where we are rapidly learning more, such as the functioning and role of the CRISPR/cas system, and finally what future research in thermal virology may be headed.