The microbiome of the marine flatworm Macrostomum lignano provides fitness advantages and exhibits circadian rhythmicity

Abstract

The close association between animals and their associated microbiota is usually beneficial for both partners. Here, we used a simple marine model invertebrate, the flatworm Macrostomum lignano, to characterize the host-microbiota interaction in detail. This analysis revealed that the different developmental stages each harbor a specific microbiota. Studies with gnotobiotic animals clarified the physiological significance of the microbiota. While no fitness benefits were mediated by the microbiota when food was freely available, animals with microbiota showed significantly increased fitness with a reduced food supply. The microbiota of M. lignano shows circadian rhythmicity, affecting both the total bacterial load and the behavior of specific taxa. Moreover, the presence of the worm influences the composition of the bacterial consortia in the environment. In summary, the Macrostomum-microbiota system described here can serve as a general model for host-microbe interactions in marine invertebrates.

A genetic and microscopy toolkit for live imaging of whole-body regeneration inMacrostomum lignano

“…The interstitial, marine flatworm M. lignano , studied for diverse biological processes (Wudarski et al, 2020) including sexual selection (Brand et al, 2020; Marie-Orleach et al, 2021), bio-adhesion (Lengerer et al, 2014), genome evolution (Wasik et al, 2015; Zadesenets et al, 2017; Wiberg et al, 2023), and host-microbiome interactions (Ma et al, 2023), is also capable of regenerating all tissues posterior to the pharynx but not anterior structures, presenting a unique opportunity to compare the molecular and cellular basis of regenerative and non-regenerative outcomes (Egger et al, 2006, 2009). In addition, M. lignano is conducive to live imaging thanks to its small body size, optical transparency, minimal autofluorescence, and robust physiology.…”