Isolation and Diagnosis of Virus Through Indicator Hosts

Abstract

Isolation followed by propagation of viruses is the first step in the characterization of a virus. Under natural field conditions, plants may be infected with more than one virus and other pathogens. Hence, it is important to isolate the virus in question under in vitro or glasshouse condition. This is usually done by inoculating the field-collected samples onto a host that produce local lesion symptoms. Inoculation may be done by mechanical means using sap extracted from infected plants or through vectors (if virus in question is not mechanically transmitted). Pure culture of the virus isolate is then made by inoculating single local lesion on to hosts that produce either local or systemic symptoms. Pure culture of the virus is inoculated (either mechanically or through vectors) onto a set of diagnostic hosts that are known to produce characteristic symptoms that would help in the identification of the causal virus.