Active but not passive passengers: Persistent-propagative plant viruses manipulate insect vectors for efficient transmission

Most plant viruses rely on insect vectors for transmission. In general, nonviruliferous vectors acquire viruses from infected plants, whereas viruliferous vectors subsequently move to uninfected plants for virus inoculation. However, they are not merely passive passengers within their vector. Persistent-propagative plant viruses, which invade and replicate in insect vectors, can actively and directly reshape their physiology, morphology, and feeding behavior to facilitate efficient transmission. Recent studies have uncovered both indirect plant-mediated mechanisms and direct vector-targeted mechanisms, including modulation of neural signaling, olfactory systems, wing development, and feeding activity. Here, we summarize current understanding of how persistent-propagative plant viruses integrate indirect plant-mediated effects with direct manipulation of insect vectors. We further discuss the ecological implications of these virus–plant–vector interactions, highlight major bottlenecks in virus–insect interaction research, and emerging technological advances that may facilitate future mechanistic studies and support innovative strategies for controlling vector-borne plant viral diseases.