Differences in the subcellular localization of tobacco mosaic virus and cucumber mosaic virus movement proteins in infected and transgenic plants

Our study reveals differences in the way that tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV) movement proteins (MPs) partition with cellular components separated into four fractions from different aged leaves of infected and transgenic plants. Immunoblot analyses showed that TMV and CMV MPs associated predominantly with components in the cell wall fractions from leaves of transgenic plants. In infected tissue, highest levels of TMV MP were found in the organelle fractions from young and middle-aged leaves whereas most of the CMV MP was found in the detergent wash of the cell wall fraction. These results remained consistent even when plants were doubly infected with TMV and CMV. These results imply that MPs of plant viruses from different taxonomic groups differentially associate with subcellular components and that MP produced by a viral infection is targeted to additional subcellular destinations than MP produced in transgenic plants.