Trichoplusia ni and Chrysodeixis includens larvae show different susceptibility to Chrysodeixis includens single nucleopolyhedrovirus per os infection

Abstract

Many factors affect the host range of baculoviruses. Chrysodeixis includens and Trichoplusia ni are two closely related members of the lepidopteran subfamily Plusiinae that are important insect pests of different crops worldwide. In Brazil, C. includens has recently become a major defoliating pest of soybean. In this study, we compared the susceptibility of C. includens and T. ni to an alphabaculovirus isolated from a C. includens population in Brazil named Chrysodeixis includens nucleopolyhedrovirus isolate GO (ChinNPV-GO). Our results showed that ChinNPV-GO infects and kills C. includens at low oral doses, whereas T. ni larvae exhibited much lower levels of susceptibility to oral infection. In contrast, ChinNPV-GO very similarly infected and killed C. includens and T. ni larvae after budded viruses were injected into the hemocoel. Altogether, we conclude that T. ni is much less susceptible to ChinNPV-GO due to a reduced ability of this virus to establish a primary infection in the midgut. Our results further support that ChinNPV-GO and other plusiinae-associated SNPVs studied to date exhibit restricted host ranges even though known hosts are phylogenetically closely related.