Purα is an essential host factor for rice stripe virus accumulation and transmission in the small brown planthopper

As a persistent-propagative plant virus, Rice stripe virus (RSV) relies on specific interactions between viral proteins and components of its vector, the small brown planthopper (SBPH), for its efficient replication and transmission. To identify vector factors involved in this process, we employed GST pull-down/MS to screen SBPH proteins that interact with RSV P3, a key nonstructural protein for virus transmission, and obtained 55 candidate proteins. Among these, Purα was selected for further investigation. A direct interaction between P3 and Purα was confirmed by co-immunoprecipitation (Co-IP). Confocal microscopy revealed extensive colocalization of Purα and P3 in the cytoplasm of Sf9 cells and critically, within key SBPH tissues for virus transmission, including the midgut, salivary glands, and ovaries. Functional studies showed that knocking down Purα via RNA interference (RNAi) inhibited viral accumulation in SBPHs, consequently reducing both horizontal and vertical transmission efficiency. Our results provide compelling evidence that RSV hijacks the vector protein Purα to promote viral accumulation within the insect body, thereby facilitating transmission. These findings deepen our understanding of plant virus-vector interactions and reveal a potential target for developing novel strategies to control virus spread.