Synergism of Cry1Ca toxicity by gut resident Enterococcus spp. in the rice stem borer, Chilo suppressalis

Geng Chen, Qianwen Li, Chen Zhang, Wanxuan Zhao, Juan Luis Jurat-Fuentes, Xuguo Zhou, Fajun Chen, Xiaowei Yang, Lanzhi Han

Research output: Contribution to journalArticlepeer-review


The bacterium Bacillus thuringiensis (Bt) is the most economically successful biopesticide to date, and Bt insecticidal proteins are produced in transgenic crops for pest control. However, relevant details in the Bt-mediated killing process remain undefined. In our previous research, we observed reduced larval susceptibility to Bt Cry1Ca in Chilo suppressalis, a major rice pest in China, after gut microbiota elimination. Here, we tested the hypothesis that gut microbiota, particularly abundant Enterococcus spp., influences C. suppressalis susceptibility to Cry1Ca. We isolated and identified four Enterococcus spp. from C. suppressalis gut microbiota and evaluated their impact on Cry1Ca toxicity. Among the four Enterococcus spp. identified, three of them (E. casseliflavus, E. faecalis, and E. mundtii) dramatically increased larval mortality when introduced in axenic C. suppressalis challenged with Cry1Ca. Gut epithelial damage by Cry1Ca promoted the translocation of Enterococcus spp. from the gut lumen into the hemocoel, where they proliferated and induced larval melanization and hemocyte apoptosis. Our combined findings demonstrate that the presence of specific gut microbiota can greatly affect susceptibility to Cry1Ca through melanization and apoptosis of hemocytes. Better understanding of the Bt intoxication process guides the development of bio-enhancers for Bt-based microbial biopesticides and potential improvement of transgenic crops.

Original languageEnglish (US)
Article number128654
JournalInternational Journal of Biological Macromolecules
StatePublished - Feb 2024
Externally publishedYes


  • Apoptosis
  • Cry1Ca toxicity
  • Enterococcus spp.

ASJC Scopus subject areas

  • Structural Biology
  • Biochemistry
  • Molecular Biology


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