Abstract:Potyvirus belonging to family Potyviridae, is the largest plant virus family, which can be responsible for severe economic losses to agriculture world-wide. P3 protein of potyviruses show relatively low homology in compared to other proteins among potyviruses and multi-functional, related with virus replication, infection, resistance and cell-to-cell movement. P3-PiPo, the newly found SMV-encoded protein, is an overlap protein produced via ribosomal frameshifting or transcriptional slippage at a highly conserved within the P3 cistron and play a key role in viral cell-to-cell movement. The functional characterization of potyvirus-encoded proteins supported the understanding of potyviruses, and promoted the research of potyviruses infectious and resistant mechanisms.