ABSTRACT
Disease producing entities, no sexual reproduction and resting spores, it has nucleic acid and protein coat, either DNA or RNA and never both, nucleic acid carries its genome, it may be single stranded or double stranded, protein coat present as an envelope around the nucleic acid. A virus is a set of one or more genomic nucleic acid molecules, normally encased in a protective coat or coats of protein or lipoprotein, which is able to mediate its own replication only within suitable host cell. Virus - a capsid-encoding organism that is composed of proteins and nucleic acids, that self-assembles in a nucleocapsid, and that uses a ribosome-encoding organism for the completion of its life cycle. Virus enters into the plant cell through wounds made mechanically or by vectors or naturally by deposition into an ovule by an infected pollen grain. Once the virus enters inside the host, it becomes naked by shedding its capsid or coat.
