Characterization of putative virulence factors of Serratia marcescens strain SEN for pathogenesis in Spodoptera litura

•Virulence factors of entomopathogenic Serratia marcescens were characterized.•The virulent S. marcescens strain SEN possessed higher hydrolytic enzymes activity.•It showed higher relative expression of the three toxin genes shlA, phlA and swr.•It was able to proliferate considerably in Spodoptera litura gut and hemolymph.•Peritrophic membrane of the treated larvae treated showed considerable damage.