The movement protein (MP) of plant virus is essential to ensure the spread viral into the cell and to neighboring cells facilitating the success of infection. Citrus leprosis disease mainly is caused by viruses of genera Cilevirus and Dichorhavirus. There is also a single report of leprosis-like symptoms in Volkamerian lemon in Hawaii caused by a species of the genus Higrevirus. Regardless of the host, all plant species infected with the leprosis-associated viruses exhibit a limitation in the systemic viral spread. Therefore, the viruses only infect the vector feeding region in the plant and adjacent cells mediated by cell-to-cell viral movement. Based on this aspect, thepresent project seeks to understand the possible involvement of the movement proteins of species included in the two main genera (Cilevirus and Dichorhavirus) with the natural limitation of viruses in ensuring systemic infection in the plant. To this end, we propose to use the heterologous Alfalfa mosaic virus (AMV) model systemthat allows evaluating the efficiency of viral movement from introduction of heterologous MPs. Thus, in this sense, the efficiency in cell-to-cell and systemic movement from citrus leprosis MPs (CL-MPs) could be analyzed by the AMV system. Still within the viral movement process, we also propose to analyze: i) tubule formation from transfection of P12 protoplasts with CL-MPs, ii) whether or notcilevirus and dichorhavirus transport mediated by MPs is dependent upon the formation of tubular structures, iii) if the cell-to-cell movement of the studied species is dependent on the nucleocapsid assembly, iv) the MPs motifs involved with viral movement and tubule formation, v) the subcellular localization of the MPs aiming the co-localization with plasmodesmata. Additionally, we intend to address the validation of the Citrus leprosis virus C infectious clone, developed in the original proposal. The expected results from theses studies may clarify whether the natural limitation in systemic infection of the citrus leprosis-associated viruses has direct connection withthe viral MPs.
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