Abstract
A large number of insect-specific viruses (ISVs) have recently been discovered, mostly from hematophagous insect vectors because of their medical importance, but little attention has been paid to important plant virus vectors such as the whitefly Bemisia tabaci, which exists as a complex of cryptic species. Public SRA datasets of B. tabaci and newly generated transcriptomes of three Chinese populations are here comprehensively investigated to characterize the whitefly viromes of different cryptic species. Twenty novel ISVs were confidently identified, mostly associated with a particular cryptic species while different cryptic species harbored one or more core ISVs. Microinjection experiments showed that some ISVs might cross-infect between the two invasive whitefly cryptic species, Middle East Asia Minor 1 (MEAM1) and Mediterranean (MED), but others appeared to have a more restricted host range, reflecting the possibility of distinct long-term coevolution of these ISVs and whitefly hosts. Moreover, analysis of the profiles of virus-derived small-interfering RNAs indicated that some of the ISVs can successfully replicate in whitefly and the antiviral RNAi pathway of B. tabaci is actively involved in response to ISV infections. Our study provides a comprehensive analysis of the RNA virome, the distinct relationships and cross-cryptic species infectivity of ISVs in an agriculturally important insect vector.