Differential Effects of Two Tomato Begomoviruses on the Life History and Feeding Preference of Bemisia tabaci

SIMPLE SUMMARY: Tomato yellow leaf curl disease is a serious problem for tomato farmers worldwide. This disease is caused by a group of viruses, namely, tomato yellow leaf curl viruses. These viruses are mainly transmitted by the sweet potato whitefly. After the virus is ingested by the whitefly through the process of feeding on diseased plants, the virus circulates in the body of the whitefly and infects its tissues. This virus–insect relationship can influence virus transmission. The life history and feeding preference of whiteflies may be affected by viral infection in a negative, neutral, or positive manner, depending on the species of virus and whitefly involved. The tomato yellow leaf curl Thailand virus (TYLCTHV) and the tomato leaf curl Taiwan virus (ToLCTV) are common in tomato fields in Taiwan. This study examined the direct and indirect effects of TYLCTHV and ToLCTV on the life history traits (longevity, fecundity, nymph survival, and nymph developmental time) and feeding preference of whiteflies. The results revealed that TYLCTHV did not affect the life history and feeding preference of the whiteflies. However, ToLCTV infection caused low fecundity and slow development when the whiteflies fed on diseased plants. ToLCTV infection also altered the feeding preference of the whiteflies. These findings could help explain why ToLCTV is less common than TYLCTHV in tomato fields in Taiwan. ABSTRACT: Tomato yellow leaf curl disease, caused by a group of closely related tomato yellow leaf curl viruses, is a major threat to tomato cultivation worldwide. These viruses are primarily transmitted by the sweet potato whitefly (Bemisia tabaci) in a persistent-circulative manner, wherein the virus circulates in the body of B. tabaci and infects its tissues. The complex relationship between viruses and whiteflies significantly influences virus transmission, with studies showing varying effects of the former on the life history and feeding preference of the latter. Whether these effects are direct or indirect, and whether they are negative, neutral, or positive, appears to depend on the specific interactions between virus and whitefly species. The tomato yellow leaf curl Thailand virus (TYLCTHV) and the tomato leaf curl Taiwan virus (ToLCTV) are two prevalent begomoviruses in fields in Taiwan. This study examined the direct and indirect effects of TYLCTHV and ToLCTV on the life history traits (longevity, fecundity, nymph survival, and nymph developmental time) and feeding preference of B. tabaci Middle East–Asia Minor 1 (MEAM1). The results revealed that TYLCTHV had no effects on these life history traits or the feeding preference of MEAM1 whiteflies. Although ToLCTV did not directly affect the longevity and fecundity of MEAM1 whiteflies, their fecundity and the nymph developmental time were negatively affected by feeding on ToLCTV-infected plants. In addition, ToLCTV infection also altered the feeding preference of MEAM1 whiteflies. The different effects of virus infection may contribute to the lower prevalence of ToLCTV compared to TYLCTHV in fields in Taiwan.