The pathosystem Tobacco etch potyvirus (TEV)-Arabidopsis thaliana ecotype Ler has been chosen for the present study. TEV genome is composed of a 9.5 kb positive polarity single-strand RNA that encodes a large ORF whose translation generates a polyprotein that is subsequently self-processed by virus-encoded proteases into 10 mature peptides [19, 20] . TEV has a moderately wide host range infecting around 149 species from 19 families [21] , although most of its natural hosts belong to the family Solanaceae. In these plants TEV induces stunting and mottling, necrotic etching and malformation in leafs [21] . A. thaliana ecotypes vary in their susceptibility to TEV. Some ecotypes (e.g., C24 and Ler) are fully susceptible [22, 23] whereas many other (e.g., Col-0 and Ws-2) do not allow for systemic movement but support replication and cellto-cell spread in inoculated leafs [22, 23] . Arabidopsis is a member of the family Brassicaceae, which belongs to a different order than the Solanaceae within the class Magnoliopsida [24] . Therefore, adaptation of TEV to A. thaliana represents a jump in host species at the taxonomic level of orders.