A CLONED CELL-LINE OF SPODOPTERA-EXIGUA HAS A HIGHLY INCREASED SUSCEPTIBILITY TO THE SPODOPTERA-EXIGUA NUCLEAR POLYHEDROSIS-VIRUS

A cloned cell line designated Se301, derived from a continuous Se3FH c ell line of the beet armyworm Spodoptera exigua, showed 10 times great er sensitivity when tested with the plaque assay to a S. exigua nuclea r polyhedrosis virus (SeNPV) as compared with the parent cell line. Ne arly 100% of Se301 cells were infected with the plaque purified isolat e SeNPV-I1 or the wild isolate SeNPV-IW. Plaques were first detected 3 -4 days in the Se301 cell line, which was 1-2 days faster than the Se3 FH cell line. The size of plaques formed in the Se301 cell line was ma rkedly larger than that of the parental cell line. At 12 h post infect ion, the production of the extracellular viruses (ECVs) in the Se301 c ell line infected with either SeNPV-I1 or SeNPV-IW was:20-40 times gre ater than that in the Se3FH cell line. In contrast, Se301 cells infect ed with SeNPV-I1 or SeNPV-IW produced polyhedral inclusion bodies (PIB s) at lower levels compared with Se3FH cells. The isolate SeNPV-I1 con sistently produced more ECVs and PIBs in both the Se301 and Se3FH cell lines than the isolate SeNPV-IW.