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SfIML-1 interacts with integrin β5 to mediate fungal conidial adhesion and immune activation in Spodoptera frugiperda

Fang-Fang Liu1, Qi-Gui Gao1, Yue Sun1

  • 1Anhui Province Key Laboratory of Integrated Pest Management on Crops, School of Plant Protection, Anhui Agricultural University, Hefei 230036, China; Key Laboratory of Agri-products Quality and Biosafety (Anhui Agricultural University), Ministry of Education, Hefei 230036, China.

Pesticide Biochemistry and Physiology
|July 23, 2026
PubMed

Insights

Soluble pattern-recognition receptors like Spodoptera frugiperda immulectin-1 (SfIML-1) cooperate with membrane receptors, specifically integrin β5, to enhance insect immune responses against fungal pathogens. This interaction boosts conidial adhesion and innate immunity activation.

Area of Science:

  • Insect immunology
  • Molecular recognition
  • Innate immunity

Background:

  • Soluble pattern-recognition receptors (SPRs) detect pathogens but their cooperation with membrane receptors is unclear.
  • Spodoptera frugiperda immulectin-1 (SfIML-1), a C-type lectin, recognizes hemocytes and fungi, enhancing cellular immunity.
  • Understanding SPR-membrane receptor interactions is crucial for insect innate immunity.

Purpose of the Study:

  • Investigate SfIML-1's receptor association and immune functions in Spodoptera frugiperda.
  • Elucidate the molecular mechanisms of cooperation between SPRs and membrane receptors.
  • Identify potential targets for sustainable pest management.

Main Methods:

  • Recombinant SfIML-1 expression and immune gene induction assays.
  • Transcriptomic profiling of SfIML-1-overexpressing cells.
  • Genome-wide identification of integrin genes.
  • Yeast two-hybrid assays and domain mapping for protein interactions.
  • Fluorescence colocalization and functional assays (adhesion, gene silencing).

Main Results:

  • Recombinant SfIML-1 induced antimicrobial peptide genes, activating innate immunity.
  • Transcriptomics revealed changes in immunity, phagocytosis, and cytoskeletal organization genes, including integrin β subunit.
  • SfIML-1 specifically interacts with integrin β5 via its carbohydrate-recognition domain.
  • SfIML-1 and β5 colocalize at the cell membrane.
  • β5 overexpression enhanced SfIML-1-mediated conidial adhesion, while silencing reduced it.

Conclusions:

  • SfIML-1 functions within a β5-associated pathway to promote fungal conidial adhesion and immune activation in S. frugiperda.
  • This study provides new insights into SPR and membrane receptor cooperation in insect innate immunity.
  • The identified pathway highlights potential targets for developing sustainable pest management strategies.
Keywords:
C-type lectinInsect immunityIntegrinPattern-recognition receptorSpodoptera frugiperda

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