The fine structure of Cymbidium ringspot virus infections in host tissues

• Published in: Journal of ultrastructure research Vol. 82; no. 1; pp. 52 - 63
• Main Authors: Russo, Marcello, Di Franco, Alessandra, Martelli, Giovanni P.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1983
• ISSN: 0022-5320; 1878-2345
• DOI: 10.1016/S0022-5320(83)90096-5

Ultrastructural studies of Nicotiana clevelandii plants systemically infected with Cymbidium ringspot virus, a member of the tombusvirus group, have shown that a clear-cut relationship exists between perioxisomes and multivesicular bodies (MVB). In infected cells, peroxisomes undergo a progressive vesiculation of the bounding membrane through the possible addition of membranous material by the endoplasmic reticulum and become very plastic. Portions of the ground cytoplasm are engulfed either through the invagination of the limiting membrane or the production of membranous appendages that fold back on the main body. Cytochemical tests have shown MVB to possess catalase and glycolate oxidase activity in the matrix. The vesicles contain RNA, a substantial amount of which is double stranded, as indicated by differential RNase digestion tests in high- and low-salt media. The double-stranded RNA may consist of replicative forms or replicative intermediates of the viral nucleic acid. If so, MVB (i.e., modified peroxisomes) may be directly involved in the replication of Cymbidium ringspot virus.