Life Cycle of a Plant Virus:
There is an incubation period in the body of an insect after it picks up virus particles from an infected plant. There also appears to be an incubation period in the plant cell after its infection with virus particles. Infection may be with viral RNA or with whole virus particles, but in the case of the plant body, it is always in the form of RNA. The changes in viral RNA reduce or change the course of viral infection. There is some evidence that RNA appears in the host nucleus before it appears in the host cytoplasm and that viral RNA is elaborated by the host cytoplasm before the viral protein is formed.
The replication of the viral RNA is indeed somewhat of an enigma because current ideas of RNA application and protein synthesis are generally related to information carried in the deoxyribonucleic acid DNA molecule. The viruses may be divided into three main classes according to the nature of their hosts:
- Plant Virus
- Animal Virus
- Bacterial Virus
The important plant viruses are Tobacco Mosaic Virus, Tobacco Satelite Virus, Turnip Yellow Mosaic, and Rugose Mosaic Virus. Generally, all crystalized plant viruses have been found to consist mainly of ribonucleoproteins.