Mycoviruses Infecting True Truffles

Viruses can be defined as small and simple obligate intracellular parasites. Virions, the complete, infectious virus particles, consist of a protein coat (capsid) enclosing the viral genome, that, in some cases, can be wrapped in an external coat derived by the host cell membrane. This set of nucleic acids encodes proteins necessary for replication, movement to adjacent plant cells (in the case of plant viruses), possibly proteins to interact with host defence and finally protein to help transmission among individuals of the host species. Genome of known viruses lacks the genetic information necessary for the generation of metabolic energy (adenosine triphosphate, ATP) or for protein synthesis (ribosomes). Viruses are therefore dependent on the host cell for these functions. Moreover, even if viruses do not have cellular structure and do not growth through their own metabolism, they reproduce themselves and are able of adaptation to the environment by internally-originate changes, then they can be probably ascribed as living organisms. From a different point of view, viruses are living entities during the intracellular phase of their life cycle, according to the Virocell concept, and can be considered as a complex assemblage of metabolically inert chemicals outside the host cell.