The molecular basis of the interactions of rhabdoviruses with their insect and plant hosts.

摘要

Maize fine streak virus (MFSV) and Maize mosaic virus (MMV) are insect transmitted plant rhabdoviruses. These viruses invade and replicate in cells of various tissues in insects, vertebrates, and plants. Therefore, insects are not only vectors but also replication hosts for rhabdoviruses. Sigma rhabdovirus only infects Drosophila flies and is transmitted to the progeny of flies through germinal cells. MFSV, MMV, and Sigma virus, and interactions with their hosts provide unique systems for characterization of molecular factors determining rhabdovirus host ranges.; The MFSV genome encodes seven genes on the antigenomic strand, whereas the MMV genome encodes six genes. More information about possible functions of MFVS and MMV proteins was obtained through in planta cellular localization studies. The results showed that the MFSV N, 4, M, and MMV P proteins target the nuclei of plant cells. In addition, rhabdovirus N and P proteins interact, and the interaction is specific to cognate proteins of each virus.; MFVS and MMV replicate in the nucleus and assemble at the inner nuclear membrane of cell, therefore nuclear import of viral proteins is critical to complete virus morphogenesis. Using virus-induced gene silencing (VIGS) combined with in planta cellular localization silencing of Importin alphas inhibits the nuclear localization of the MFSV N protein and N-P complex in plant cells, suggesting that two proteins are dependent on Importin alphas for nuclear import in plants.; Microarray studies showed Sigma virus infection triggers different immune responses in drosophila compared to the other drosophila viruses. The Imd signaling pathway was identified as the main component of the drosophila anti-Sigma virus response. This is the first comparative study showing that viruses can induce different immune pathways in drosophila, similarly to Gram-negative bacteria and Gram-positive bacteria, which activate the Imd and Toll pathways, respectively. A comparison of how different insects, including drosophila, leafhoppers and planthoppers, respond to rhabdovirus infections should prove interesting.