20-hydroxyecdysone (20E) increases its titre level during the wandering stage and influences innate immunity in many holometabolous insects. However, the function of 20E as an immune-activator or -suppressor needs to be determined. Here, the transcriptome of the peptidoglycan-challenged fat body of the cotton bollworm, Helicoverpa armigera, was analysed using Illumina sequencing technology. Overall, 32 073 unigenes were assembled with a mean length of 643 nucleotides. Gene expression dynamics in the fat body during the wandering stage and of pe...