Selective strengthening of lipid metabolism and the rapid immune response of Ostrinia furnacalis larvae parasitized by Macrocentrus cingulum

Abstract

The Macrocentrus cingulum is a vital endoparasitic wasp that parasites in Ostrinia furnacalis larvae. It has been widely utilized for biological control of corn borer. Although previous studies have explored how the wasps suppress the host's immunity, further research is required to determine the impact of the wasps on the host's lipid metabolism and activated immune response. In this study, high-throughput transcriptome sequencing, quantitative real-time PCR, and physiological and biochemical methods were used to investigate the balance between energy metabolism and immunity in parasitic systems. The results showed that specific genes linked to lipid metabolism and transportation were up-regulated in parasitized O. furnacalis larvae, including AKHR, AKH, apoLpIII, and FAS. Additionally, M. cingulum triggered immune responses in the parasitized larvae, leading to rapid recognition and the production of immunity effectors, such as Lysozyme and antimicrobial peptides, to protect against the invading wasps. The phenoloxidase (PO) activity was inhibited as a result of parasitization. Parasitism selectively promoted lipid metabolism and activated the immune recognition response, significantly up-regulated immune pattern recognition receptors (PRRs) and effector genes, but suppressed the PPO cascade response in O. furnacalis larvae. This study can shed light on lipid metabolism, immune response, and activating the immune recognition response for parasitoid and host co-evolution and provide insight into the biological control of O. furnacalis.