The Dynamic Distribution of Wolbachia and Rickettsia in AsiaII1 Bemisia tabaci

Simple Summary: Bacterial endosymbionts play important roles in the life history of herbivorous insects, including supplying nutrients allowing exploitation of unbalanced diets, increasing the survivorship and fecundity of hosts, protecting hosts against entomopathogenic fungi and parasitoid wasps, ameliorating the detrimental effects of heat, and broadening the range of suitable food plants. The important function of bacterial endosymbionts is that they can manipulate the reproduction of their hosts. However, all functions of endosymbionts must rely on vertical transmission to spread within the population, such as Wolbachia, Rickettsia, and Cardinium. So, we studied the spatial and temporal distribution of Wolbachia and Rickettsia in Asia II 1 Bemisia tabaci. The results showed that the titers of Wolbachia and Rickettsia in the 3-120 h old eggs changed in a "w" pattern, and the location of Wolbachia and Rickettsia in the egg changed from egg stalk to egg base, and then from the egg base to egg posterior, and finally back to the middle of egg in a Rickettsia and Wolbachia coinfected whitefly host. Our study helps to explain the vertical transmission mechanism of bacterial endosymbionts and the distribution of bacterial endosymbionts in different tissues in the host. Wolbachia and Rickettsia are bacterial endosymbionts that can induce a number of reproductive abnormalities in their arthropod hosts. We screened and established the co-infection of Wolbachia and Rickettsia in Bemisia tabaci and compared the spatial and temporal distribution of Wolbachia and Rickettsia in eggs (3-120 h after spawning), nymphs, and adults of B. tabaci by qPCR quantification and fluorescent in situ hybridization (FISH). The results show that the titer of Wolbachia and Rickettsia in the 3-120 h old eggs showed a "w" patterned fluctuation, while the titers of Wolbachia and Rickettsia had a "descending-ascending descending-ascending" change process. The titers of Rickettsia and Wolbachia nymphal and the adult life stages of Asia II1 B. tabaci generally increased with the development of whiteflies. However, the location of Wolbachia and Rickettsia in the egg changed from egg stalk to egg base, and then from egg base to egg posterior, and finally back to the middle of the egg. These results will provide basic information on the quantity and localization of Wolbachia and Rickettsia within different life stages of B. tabaci. These findings help to understand the dynamics of the vertical transmission of symbiotic bacteria.