Analysis of reassortant and intragenic recombination in Cypovirus.

Cypoviruses (CPVs) are RNA viruses with segmented double-stranded genome and major pathogens of various insects, including economic insects like silkworms and pest insects for agricultural crops and forests. Genome reassortment and recombination are common phenomenon for viruses as a mechanism to expand host range and increase virulence. In the present study, we analyzed the reassortant and recombination events for CPVs. The results showed that two genome segments (S1 and S4) of BmCPV1-YN shared higher nucleotide identity with the corresponding segment of BmCPV1-I while others were all more closely to BmCPV1-SZ, suggesting BmCPV1-YN was originated from reassortant events between BmCPV1-I and BmCPV1-SZ. Recombination analyses revealed that S6 of BmCPV1-YN was a recombinant segment derived from BmCPV1-I and BmCPV1-SZ, and S10 of DpCPV1 was a recombinant segment emerged from BmCPV1-I and LdCPV1. Our findings provide the evidence for the fact that CPVs could undergo reassortant and recombinant events and enrich the knowledge about etiology and molecular epidemiology of CPVs.