Genetic diversity and host relationships of endosymbiotic bacteria in the Asian cryptic species of Bemisia tabaci from Bangladesh

Endosymbiotic bacteria are common in many herbivorous insects. Bemisia tabaci is a phloem-sapping pest of various crop plants and is known to harbor at least five endosymbionts. This species is a complex of at least 40 genetically distinct but morphologically indistinguishable cryptic species worldwide. Endosymbiont composition has been studied in invasive cryptic species such as MEAM1 and MED, but little information exists regarding the indigenous genetic groups in Asia. Here, we determined the endosymbiont profiles of four indigenous Asian cryptic species (Asia I, Asia II 1, Asia II 5 and Asia II 10) of B. tabaci identified in Bangladesh. Overall, the infection rates of Arsenophonus, Cardinium, Hamiltonella, Rickettsia, and Wolbachia were 93%, 86%, 0%, 31%, and 88%, respectively. Phylogenetic analysis revealed two subgroups in Arsenophonus (A1, A2) and Rickettsia (R1, R2), but only one subgroup in Cardinium (C2) and Wolbachia (W1). Each endosymbiont showed varying rates of infection in the four cryptic species and most were co-infected with various combinations. The results of this study provide important information on the relationships between the endosymbionts and cryptic species of B. tabaci indigenous to Asia.