A gut symbiotic bacterium enhances baculovirus resistance in
Spodoptera frugiperda
by maintaining peritrophic matrix integrity
Lin Guo, Wenyi Jin, Qin Kang, Yan Tong, Huixian Shi, Jihong Zhang, Xuan Li, Hongtuo Wang, Qilian Qin, Qian Meng, Huan Zhang Abstract
BACKGROUND
Spodoptera frugiperda is a major agricultural pest worldwide, whereas Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) serves as an important microbial control agent against this pest. Resident gut bacteria are increasingly recognized as important modulators of insect–pathogen interactions; however, whether and how they influence SfMNPV infection in S. frugiperda remains unclear. We therefore investigated how gut bacteria modulate host resistance to SfMNPV.
RESULTS
Antibiotic‐mediated depletion of gut bacteria increased larval susceptibility to SfMNPV. Transcriptomic analysis further revealed that gut bacterial depletion downregulated midgut genes associated with immune defense, digestive functions and peritrophic matrix (PM) maintenance. Among seven culturable midgut bacterial isolates, reinoculation with Glutamicibacter soli significantly enhanced larval resistance to SfMNPV. Pre‐feeding with either the G. soli culture supernatant or cell lysis precipitate also increased larval resistance and partially reversed transcriptional changes caused by gut bacterial depletion before viral challenge, including the downregulation of peritrophin‐1. RNAi‐mediated silencing of peritrophin‐1 disrupted PM structure, increased PM permeability, and enhanced larval susceptibility to SfMNPV. Consistently, G. soli reinoculation restored PM integrity impaired by gut bacterial depletion.
CONCLUSION
These findings identify maintenance of PM integrity as an important mechanism contributing to gut symbiotic bacterium‐mediated resistance to SfMNPV. The study advances our understanding of how gut bacteria influence baculovirus infection in insect hosts and provides potential microbial and molecular targets for improving baculovirus‐based pest management. © 2026 Society of Chemical Industry.