Answer:
Presence of cell wall around plant and bacteria cells do not allow the budding of enveloped viruses.
Explanation:
During infection, replication of genome and formation of capsid proteins of enveloped viruses within the host cell is followed by assembly of capsid around each viral genome molecule which in turn bud off from the membrane of the host cell. As the new virus buds off from the cell surface, it acquires envelop from the host cell.
The presence of cellulosic and peptidoglycan cell walls around plant and bacteria cells respectively does not allow the budding of the enveloped viral particles. Consequently, these viruses can not acquire the envelope and hence, do not affect these cells with cell walls.
