Immune gene transcription in Drosophila adult flies infected by entomopathogenic nematodes and their mutualistic bacteria.
Despite impressive advances in the broad field of insect innate immunity, our understanding of the molecular basis of insect immune responses to nematode infections remains incomplete. Here we have investigated the transcriptional induction of immune pathway genes in the fruit fly Drosophila melanogaster upon infection with the entomopathogenic (or insect pathogenic) nematodes Heterorhabditis bacteriophora and their mutualistic bacteria Photorhabdus luminescens, either collectively or separately. We show that in most cases, infection of wild-type adult flies with Heterorhabditis nematodes carrying or lacking mutualistic Photorhabdus bacteria results in the up-regulation of genes in the Toll, Imd, JAK/STAT, JNK and TGF-beta pathways. We also find that direct injection of Photorhabdus bacteria into flies fails to induce the transcription of antimicrobial peptide genes and stress-related genes in Drosophila. These results suggest that Heterorhabditis nematodes and their associated Photorhabdus bacteria employ distinct strategies to evade the Drosophila immune response and establish infection.
Insect Infection and Immunity Lab, Department of Biological Sciences, Institute for Biomedical Sciences, Columbian College of Arts and Sciences, The George Washington University, Washington, DC 20052, USA.
J C
JC
Castillo
U
U
Shokal
I
I
Eleftherianos
D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology / Q000469:parasitology; D005786:Gene Expression Regulation; D056724:Immunity, Humoral; D007113:Immunity, Innate; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D020637:Photorhabdus / Q000502:physiology*; D016133:Polymerase Chain Reaction; D017172:Rhabditoidea / Q000382:microbiology / Q000502:physiology*; D013559:Symbiosis; D014158:Transcription, Genetic
D023181:Antimicrobial Cationic Peptides; D019476:Insect Proteins