Evaluation of vector susceptibility in and to Tibet orbivirus.

Mosquito-borne viruses cause various infectious diseases in humans and animals. Tibet orbivirus (TIBOV), a newly identified arbovirus, efficiently replicates in different types of vertebrate and mosquito cells, with its neutralizing antibodies detected in cattle and goats. However, despite being isolated from midges and mosquitoes, there has been a notable absence of systematic studies on its vector competence. Thus, in this study, and were reared in the laboratory to measure vector susceptibility through blood-feeding infection. Furthermore, RNA sequencing was used to examine the overall alterations in the transcriptome following TIBOV infection. The results revealed that exhibited a high susceptibility to TIBOV compared to . Effective replication of the virus in midguts occurred when the blood-feeding titer of TIBOV exceeded 10 plaque-forming units mL. Nevertheless, only a few TIBOV RNA-positive samples were detected in the saliva of and , suggesting that these mosquito species may not be the primary vectors for TIBOV. Moreover, at 2 dpi of TIBOV, numerous antimicrobial peptides downstream of the Toll and Imd signaling pathways were significantly downregulated in , indicating that TIBOV suppressed mosquitos' defense to survive in the vector at an early stage. Subsequently, the stress-activated protein kinase JNK, a crucial component of the MAPK signaling pathway, exhibited significant upregulation. Certain genes were also enriched in the MAPK signaling pathway in TIBOV-infected at 7 dpi.IMPORTANCETibet orbivirus (TIBOV) is an understudied arbovirus of the genus . Our study is the first-ever attempt to assess the vector susceptibility of this virus in two important mosquito vectors, and . Additionally, we present transcriptome data detailing the interaction between TIBOV and the immune system of , which expands the knowledge about orbivirus infection and its interaction with mosquitoes.