Symbiont-Derived Antimicrobials Contribute to the Control of the Lepidopteran Gut Microbiota. Issue 1 (19th January 2017)

• Record Type: Journal Article
• Authors: Shao, Yongqi; Chen, Bosheng; Sun, Chao; Ishida, Keishi; Hertweck, Christian; Boland, Wilhelm
• Is Part Of: Cell chemical biology. Volume 24:Issue 1(2017)
• Page Start: 66
• Page End: 75
• Publication Date: 2017-01-19
• Subjects: antimicrobial peptide -- defensive symbiont -- insect herbivore -- ecological function; Biochemistry -- Periodicals; 572.05
• DOI: 10.1016/j.chembiol.2016.11.015
• Languages: English
• ISSNs: 2451-9456

Abstract

Summary: Insects develop efficient antimicrobial strategies to flourish in a bacterial world. It has long been proposed that native gut microbiota is an important component of host defense; however, the responsible species have rarely been isolated to elucidate the mechanism of action. Here we show that the dominant symbiotic bacterium Enterococcus mundtii associated with the generalist herbivore Spodoptera littoralis actively secretes a stable class IIa bacteriocin (mundticin KS) against invading bacteria, but not against other gut residents, facilitating the normal development of host gut microbiota. A mundticin-defective strain lost inhibitory activity. Furthermore, purified mundticin cures infected larvae. Thus, the constitutively produced antimicrobials by native extracellular symbionts create a significant chemical barrier inside limiting invader expansion. This unique property also benefits E. mundtii itself by providing a competitive advantage, contributing to its dominance within complex microbial settings and its prevalence across Lepidoptera, and probably promotes the long-term cooperative symbiosis between both parties. Graphical Abstract: Highlights: The gut bacterium E. mundtii of S. littoralis produces an antimicrobial peptide Mundticin KS strongly inhibits some of the competing and potentially pathogenic organisms Mundticin KS expresses in vivo and can impair pathogen colonization Abstract : Shao et al. show that the extracellular symbiont E. mundtii of the cotton leafworm S. littoralis selectively clears pathobionts from the host gut lumen by secreting a stable antimicrobial peptide, which facilitates the normal development of gut microbiota and reduces risks of infection via the gut.