IntroductionPotato virus X (PVX) is a plant RNA virus. Its infection cycle includes invasion of the host plant, RNA replication, translation of viral proteins, cell-to-cell movement, and release of new virions. Upon infection, PVX releases its positive-strand RNA genome from the virion and produces a viral replicase using the host's translation machinery. Replicase synthesizes negative-strand RNA. New genomic plus-strand RNAs (gRNAs) and subgenomic RNAs (sgRNAs) are subsequently produced. Movement and coat proteins are translated by sgRNAs for encapsidation and movement across plasmodesmata. In this mini-review, all aspects of the PVX viral infection cycle are discussed. Classification Potato virus It therefore belongs to class IV of the Baltimore system. PVX is a member of the Potexvirus genus. Together with eight other genera, this genus belongs to the family Alphaflexiviridae [1]. Morphology and contents of virions PVX forms small filamentous virions that have a deeply grooved surface [2]. The bending strands consist of a single positive-strand genomic RNA coated with the viral coat protein (CP). The helical structure has a pitch of 3.6 nm and contains 8 CP 7/8 subunits per turn [3]. Full-length filaments have a pattern length of 515 nm with a diameter of 13 nm [4]. CP consists of a single domain with a high α-helix content [4]. The N-terminal part of this domain is exposed on the surface while the C-terminal region is buried in the virion. Several experiments indicate that CP is an O-glycoprotein. Equal amounts of galactose and fructose residues are O-linked to an acetylated serine residue in the N-terminal region [2]. This mediates the formation of a structure... half the paper... but 10%. This is despite obtaining high viral titers. Asymptomatic plants are considered carriers of PVX and represent an important source of infection. In more severe conditions necrotic streaking and severe mosaicking, wrinkling and roughness of the leaves may occur. Especially in the case of mixed infections with potato virus Y (PVY), yield losses can be up to 50%. Many potato plants carry PVX resistance genes. Two resistance genes have been identified so far. One gene product mediates salicylic acid systemic defense responses, while the other encodes the Rx protein. This protein has a nucleotide binding site (NBS) and a leucine-rich repeat (LRR). The native fold of Rx confers an inactive conformation. Following interactions with the viral CP, Rx partially unfolds, hence its NBS-LRR domain [27]. This activates the signaling cascade that mediates resistance to the virus.