A REINTERPRETATION OF AMORPHOUS INCLUSIONS IN AUCUBA STRAIN OF TOBACCO MOSAIC VIRUS

Light and electron microscope studies were made of Turkish tobacco plants systemically infected with common tobacco mosaic virus and with the aucuba strain of this virus. These showed the large amorphous inclusions which are conspicuous in plants infected with the aucuba strain to be structurally different from X-bodies in plants infected with common TMV. The former are made up largely of masses of angled-layer aggregates and thus have a high virus content. X-bodies are composed mainly of proteinaceous filaments and ribosomes and contain relatively few virus particles. Hypotheses on origin and composition of X-bodies, based on Sheffield's studies of the amorphous inclusions from the aucuba strain, thus are of questionable validity. © 1969.