Identification of a novel immune-related gene in the immunized black soldier fly, Hermetia illucens (L.)

The larvae of Hermetia. illucens have a high probability of coming into contact with microorganisms such as bacteria and fungi. Therefore, the survival of H. illucens is primarily the protection of their own against microbial infection. This effect depends on the development of the innate immune system. Antimicrobial Peptides (AMPs) exhibit antimicrobial activity against other bacterial strains and can provide important data to understand the basis of the innate immunity of H. illucens. In this study, we injected larvae with Enterococcus. faecalis (gram-positive bacteria) and Serratia. marcescens as (gram-negative bacteria) to test the hypothesis that H. illucens is protected from infection by its immune-related gene expression repertoire. To identify the inducible immune-related genes, we performed and cataloged the transcriptomes by RNA-Seq analysis. We compared the transcriptomes of whole larvae and obtained a DNA fragment of 465 bp including the poly (A) tail by RACE as a novel H. illucens immune-related gene against bacteria. A novel target mRNA expression was higher in immunized larvae with E. faecalis and S. marcescens groups than non-immunized group. We expect our study to provide evidence that the global RNA-Seq approach allowed for the identification of a gene of interest which was further analyzed by quantitative RT-PCR, together with genes chosen from the available literature.