Nanomaterial ZIF8@ZIF67 may regulate ROS/BmRelish axis to enhance the silkworm resistance against Bacillus cereus

Abstract

Nanomaterials have broad application prospects in biomedicine, environmental protection, improving agricultural production efficiency and pest control. Our previous study demonstrated that the nanomaterial ZIF-8@ZIF-67 improves the survival rate of silkworms following Bacillus cereus infection. However, the underlying mechanism remained unclear. Here, we elucidated the molecular basis of this enhanced resistance by employing integrated transcriptomic and metabolomic analyses. We propose that ZIF-8@ZIF-67 induces ROS generation, which could in turn activate BmRelish, a key immune pathway component, thereby strengthening host immunity. Transcriptomic profiling identified a total of 547 significantly differentially expressed genes (DEGs). Among these, the short peptidoglycan recognition proteins PGRP-S7 and PGRP-S3 were significantly upregulated and the oxidative phosphorylation pathway was notably enriched. PGRP-S3 expression in the ZIF8@ZIF67-treated group was elevated by 28.5-fold compared to the control, highlighting a strong immune-related transcriptional response to nanomaterial exposure. Furthermore, ZIF8@ZIF67 exposure induced a 3.8-fold upregulation of BmRelish, a critical downstream effector of the Imd signaling pathway, and concurrently activated multiple components of the Toll pathway—including PGRP-S7/S3, GNBP3, TLR3, and Dorsal. These transcriptional changes collectively promoted robust induction of antimicrobial peptides such as BmAttacin, BmCecA, and BmCecB1. Metabolomic analysis revealed 317 differentially accumulated metabolites (DAMs), including key molecules such as α-linolenic acid and glutathione (GSH/GSSG), which collectively modulated antioxidant defense, energy metabolism, and lipid metabolism. Integrated omics analysis further identified that BmRelish may act as a central regulatory node, orchestrating the coordination between immune signaling pathways and metabolic homeostasis to establish a functional “immune-metabolic network”. This regulatory framework enhanced the antimicrobial capacity of silkworms.