Viral elements and host cellular proteins in intercellular movement of Bamboo mosaic virus.

As a member of the genus Potexvirus, Bamboo mosaic virus (BaMV) also belongs to the plant viruses that encode triple gene block proteins (TGBps) for intercellular movement within the host plants. Recent studies of the movement mechanisms of BaMV have revealed similarities and differences between BaMV and other potexviruses. This review focuses on the general aspects of viral and host elements involved in BaMV movement, the interactions among these elements, and the possible pathways for intra- and intercellular trafficking of BaMV. Major features of BaMV trafficking that have not been demonstrated in other potexviruses include: (i) the involvement of replicase, (ii) fine regulation by coat protein phosphorylation, (iii) the key roles played by TGBp3, (iv) the use of virions as the major transported form, and (v) the involvement of specific host factors, such as Ser/Thr kinase-like protein of Nicotiana benthamiana. We also highlight areas for future study that will provide a more comprehensive understanding of the detailed interactions among viral movement proteins and host factors, as well as the regulatory mechanisms of virus movement. Finally, a model based on the current knowledge is proposed to depict the diverse abilities of BaMV to utilize a wide range of mechanisms for efficient intercellular movement.