Coinfection of <i>Spodoptera exigua</i> and <i>Spodoptera frugiperda</i> Cell Lines with the Nuclear Polyhedrosis Viruses of <i>Autographa californica</i> and<i>Spodoptera exigua</i>

Abstract

The <i>Autographa californica</i> multinucleocapsid nuclear polyhedrosis virus (AcMNPV) has a broad host range among Lepidoptera. In contrast, the <i>Spodoptera exigua</i> MNPV (SeMNPV) can replicate efficiently only in <i>S. exigua</i> larvae or <i>S. exigua</i>-derived cell lines. In this study, we examined the coinfection of <i>S. exigua</i> Se301 and <i>Spodoptera frugiperda</i> IPLB-SF21AEII (Sf21) cell lines with SeMNPV and AcMNPV recombinant (Ac360-<i>501β-gal</i>) which was constructed for expression of β-galactosidase under control of the polyhedrin promoter. Coinfection led to the restriction as the level of late gene expression, nonoccluded virus production, and DNA replication of Ac360-<i>501β-gal</i> in both Se301 and Sf21 cell lines. In contrast, Ac360-<i>501β-gal</i> supported the SeMNPV replication in Sf21 cells. Occurrence of recombinants, between Ac360-<i>501β-gal</i> and SeMNPV, with expanded host range was not observed in coinfected Sf21 cells. This suggests that Ac360-<i>501β-gal</i> supports the SeMNPV replication through <i>trans</i>-activation.