Rice stripe virus counters reduced fecundity in its insect vector by modifying insect physiology, primary endosymbionts and feeding behavior

Virus-vector relationships can be complex and diverse as a result of long-term coevolution. Understanding these interactions is crucial for disease and vector management. Rice stripe virus (RSV) is known to be transovarially transmitted within its vector, Laodelphax striatellus, and causes serious rice stripe disease. In RSV-infected L. striatellus, we found contrasting changes in vector fecundity, physiology, primary endosymbionts (i.e. yeast-like symbionts, YLS) and feeding behavior that can interact to affect the spread of RSV. RSV-infected L. striatellus exhibited a significant decrease in fecundity that could lead a reduction of viruliferous individuals in populations. As a potential response to this loss, RSV infection also significantly shortened nymphal stage duration, which can strengthen RSV vertical circulation in L. striatellus populations and promote RSV spreading by adult migration and dispersal. Down-regulated JHAMT and up-regulated CYP307A1 in the juvenile hormone and ecdysteroid pathways, respectively, were linked to accelerated development. RSV-infected adults were also found to have higher body weight in conjunction with increased YLS abundance. Furthermore, prolonged host plant phloem exposure to salivation by RSV-infected adults should further enhance RSV horizontal transmission. Our study highlights potential strategies of RSV in enhancing its transmission, and provides new insights into the complexity of virus-vector interactions.