Impact of TYLCV infection on host selection and feeding behavior of MED Bemisia tabaci on pepper plants.

The tomato yellow leaf curl virus (TYLCV), spread by the vector insect Bemisia tabaci, dramatically reduces worldwide tomato production and quality. Plant-mediated interactions between TYLCV and vector whiteflies commonly occur when previous infestations induce both volatile and nonvolatile changes in the shared host. These induced changes of the shared host may differentially affect subsequent interacting species within the plant-insect-virus tripartite system. These altered volatile profiles can be perceived as airborne cues that enhance or suppress defense responses in neighboring conspecifics, a phenomenon known as "plant-plant communication." Here, we present the first evidence that TYLCV-infected Mediterranean (MED) B. tabaci (hereafter referred to as viruliferous MED) preferentially settles and oviposits on previously infested peppers, an alternative host for TYLCV, over those merely exposed and intact ones. Furthermore, differences in feeding behavior of viruliferous MED, assessed using an electrical penetration graph, clearly indicate that these MED whiteflies feed more effectively on previously infested and exposed peppers than on healthy ones. Our results suggest that the suppression of pepper defenses-both nonvolatile and volatile-by previous infestation and exposure to viruliferous MED promotes alternative host-mediated mutualism between MED and TYLCV. These findings provide insight into peppers, functioning as alternative hosts, mediating the interactions between TYLCV and its vector MED whiteflies. Moreover, our results may enhance the understanding of TYLCV epidemics, particularly in the context of the rapid invasion of MED B. tabaci, thereby facilitating the development of novel management strategies for controlling this viral pathogen and its devastating whiteflies.