Lepidopteran species have a variety of defence strategies against bacterial infections.
The insect immune system has versatile ways of coping with microbial insults. Currently, innate immune priming has been described in several invertebrates, and the first insights into its mechanistic basis have been described. Here we studied infections with two different strains of Serratia marcescens bacteria in two different Lepidopteran hosts. The results reveal fundamental differences between the two hosts, a well-known model organism Galleria mellonella and a non-model species Arctia plantaginis. They differ in their strategies for resisting oral infections; priming their defences against a recurring sepsis; and upregulating immunity related genes as a response to the specific pathogen strains. The two bacterial strains (an environmental isolate and an entomopathogenic isolate) differ in their virulence, use of extracellular proteases, survival in the larval gut, and in the immune response they evoke in the hosts. This study explores the potential mechanistic explanations for both host and pathogen specific characters that significantly affect the outcome of Gram-negative bacterial infection in Lepidopteran larvae. The results highlight the need to pay greater attention to the differences between model and non-model hosts, and closely related pathogen strains, in immunological studies.
Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, P.O. Box 35, 40014 University of Jyväskylä, Finland. Electronic address: l.mikonranta@exeter.ac.uk.
Lauri
L
Mikonranta
Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, P.O. Box 35, 40014 University of Jyväskylä, Finland.
Franziska
F
Dickel
Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, P.O. Box 35, 40014 University of Jyväskylä, Finland.
Johanna
J
Mappes
Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, P.O. Box 35, 40014 University of Jyväskylä, Finland; Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, P.O. Box 65, 00014 University of Helsinki, Finland.
Dalial
D
Freitak
D000818:Animals; D054884:Host-Pathogen Interactions / Q000276:immunology* / Q000502:physiology; D007915:Lepidoptera / Q000276:immunology* / Q000382:microbiology*; D013045:Species Specificity
6-Tox; Arctia plantaginis; Bacterial infection; Cecropin; Defensin; Extracellular protease; Galleria mellonella; Gene expression; Immune priming; Immunity; Resistance; Serratia marcescens; Tolerance; Virulence