Beneficial commensal bacteria promote Drosophila growth by downregulating the expression of peptidoglycan recognition proteins

Marialaura Gallo; Justin M Vento; Pauline Joncour; Andrea Quagliariello; Elisa Maritan; Nuno F Silva-Soares; Matteo Battistolli; Chase L Beisel; Maria Elena Martino

doi:10.1016/j.isci.2022.104357

Beneficial commensal bacteria promote Drosophila growth by downregulating the expression of peptidoglycan recognition proteins

iScience. 2022 May 5;25(6):104357. doi: 10.1016/j.isci.2022.104357. eCollection 2022 Jun 17.

Authors

Affiliations

¹ Department of Comparative Biomedicine and Food Science, University of Padova, Padova, Italy.
² Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, USA.
³ CNRS, Université Rennes 1, UMR 6553, Rennes, France.
⁴ Department of Biology, University of Padova, Italy.
⁵ Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz-Centre for Infection Research (HZI), Würzburg, Germany.
⁶ Medical faculty, University of Würzburg, Würburg, Germany.

Abstract

Commensal bacteria are known to promote host growth. Such effect partly relies on the capacity of microbes to regulate the host's transcriptional response. However, these evidences mainly come from comparing the transcriptional response caused by commensal bacteria with that of axenic animals, making it difficult to identify the animal genes that are specifically regulated by beneficial microbes. Here, we employ Drosophila melanogaster associated with Lactiplantibacillus plantarum to understand the host genetic pathways regulated by beneficial bacteria and leading to improved host growth. We show that microbial benefit to the host relies on the downregulation of peptidoglycan-recognition proteins. Specifically, we report that bacterial proliferation triggers the lower expression of PGRP-SC1 in larval midgut, which ultimately leads to improved host growth and development. Our study helps elucidate the mechanisms underlying the beneficial effect exerted by commensal bacteria, defining the role of immune effectors in the relationship between Drosophila and its gut microbes.

Keywords: immunology; microbiology; microbiome.