VIRUS–HOST INTERACTIONS, WITH EMPHASIS ON CERTAIN CYTOPATHIC PHENOMENA

Abstract

The apparent role played by each participant in virus–plant interactions, as suggested by symptom expression, is discussed. To explain the markedly different reactions of identical hosts to closely related virus strains, it is proposed on the basis of present concepts regarding protein synthesis and RNA-virus replication, that the viral genome, insofar as it does not code for coat protein and for enzyme(s) required for replication of viral ribonucleic acid (RNA), may be "translated" into protein acting as the true cytopathic agent.Information on the nature of certain viral-cytopathogenic effects in hypersensitive and susceptible hosts, mainly as revealed by electron microscopy, is presented. The dramatic and fatal intracellular disorganization shown by hypersensitive hosts and suggestive of cytolytic processes invited a search for the presence and possible role of organelles containing hydrolytic enzymes (lysosomes). The in vitro detection of particle-bound acid phosphatase in different types of organelles, confirmed by electron microscopy, may explain at least some aspect of the observed cellular degeneration.