Outcome of mixed DNA virus infections on Spodoptera exigua susceptibility to SeMNPV
Baculovirus-based biopesticides have been developed for an efficient control of lepidopteran pests; however, very few studies have assessed the effect of other viral microorganisms that might coexist with the applied baculovirus pesticide. Systematic studies are needed to predict the effect of such microorganisms on the baculovirus efficacy following application in the field. In this context, we examined the effect of a sublethal doses of the DNA virus Junonia coenia densovirus (JcDV) on the infectivity of the Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) when infecting the same host, Spodoptera exigua. In our experimental conditions, the infection timing was critical for the mixed infection outcome. The consecutive infections with SeMNPV and later with JcDV did not affect the larval mortality or the measured infection parameters compared with single infection with the baculovirus. However, when larvae were first infected with JcDV, a clear antagonism was detected between both viruses and resulted in a patent reduction in viral pathogenicity and deleterious effects observed in the SeMNPV progeny. On the other hand, the simultaneous infection with both viruses led to an additive effect of the mortalities caused by the two viruses. Our results reveal that temporal order of the infection with one or the other virus affects the outcome of mixed viral infections on the targeted pest and may influence the ecology of baculovirus and its use as biological insecticide.
KeywordsMixed infection S. exigua SeMNPV JcDV Infection timing
This study was partially supported by the Spanish Ministry of Economy, Industry and Competitiveness and by European FEDER funds (Grant AGL2014-57752-C2-02). AF was recipient of a Ph.D. grant from the Spanish Ministry of Education, Culture and Sport (Grant FPU16/02363). We also want to thank Rosa Maria González-Martínez for her excellent help with insect rearing and laboratory management. We thank the anonymous reviewers for their useful comments and suggestions.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
Informed consent was obtained from all individual participants included in the study.
This article does not contain any studies with human participants or vertebrates performed by any of the authors.
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