Antimicrobial Peptides Keep Insect Endosymbionts Under Control

• Published in: Science (American Association for the Advancement of Science) 2011-10, Vol.334 (6054), p.362-365
• Main Authors: Login, Frédéric H., Balmand, Séverine, Vallier, Agnès, Vincent-Monégat, Carole, Vigneron, Aurélien, Weiss-Gayet, Michèle, Rochat, Didier, Heddi, Abdelaziz
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Antimicrobials; Autoecology; Bacteria; Bacterial Outer Membrane Proteins - metabolism; Bacterial Proteins - metabolism; Bacteriocytes; Biological and medical sciences; Cellular Biology; Chaperonin 60 - genetics; Chaperonin 60 - metabolism; Cytoplasm - metabolism; Endosymbionts; Epithelial cells; Epithelial Cells - metabolism; Escherichia coli - cytology; Escherichia coli - drug effects; Fat body; Fat Body - metabolism; Fundamental and applied biological sciences. Psychology; Gammaproteobacteria - cytology; Gammaproteobacteria - drug effects; Gammaproteobacteria - metabolism; Gammaproteobacteria - physiology; Genomes; Insect genetics; Insect larvae; Insect Proteins - genetics; Insect Proteins - metabolism; Insect Proteins - pharmacology; Insects; Life Sciences; Microbial corrosion; Micrococcus luteus - drug effects; Oocytes - metabolism; Peptides; Protozoa. Invertebrata; RNA Interference; Saccharomyces cerevisiae - drug effects; Symbiosis; Weevils; Weevils - cytology; Weevils - metabolism; Weevils - microbiology
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1209728

Vertically transmitted endosymbionts persist for millions of years in invertebrates and play an important role in animal evolution. However, the functional basis underlying the maintenance of these long-term resident bacteria is unknown. We report that the weevil coleoptericin-A (ColA) antimicrobial peptide selectively targets endosymbionts within the bacteriocytes and regulates their growth through the inhibition of cell division. Silencing the colA gene with RNA interference resulted in a decrease in size of the giant filamentous endosymbionts, which escaped from the bacteriocytes and spread into insect tissues. Although this family of peptides is commonly linked with microbe clearance, this work shows that endosymbiosis benefits from ColA, suggesting that long-term host-symbiont coevolution might have shaped immune effectors for symbiont maintenance.