Identification and characterization of a skin microbiome on suggests environmental microbes confer cuticle protection.

Unlabelled: In the wild, are emersed in environments teeming with a veritable menagerie of microorganisms. The cuticular surface serves as a barrier and first point of contact with their microbial environments. In this study, we identify microbes from natural habitats that associate with its cuticle, constituting a simple "skin microbiome." We rear our animals on a modified CeMbio, mCeMbio, a consortium of ecologically relevant microbes. We first combine standard microbiological methods with an adapted micro skin-swabbing tool to describe the skin-resident bacteria on the surface. Furthermore, we conduct 16S rRNA gene sequencing studies to identify relative shifts in the proportion of mCeMbio bacteria upon surface-sterilization, implying distinct skin- and gut-microbiomes. We find that some strains of bacteria, including sp. JUb101 are primarily found on the nematode skin, while others like JUb19 and MYb71 are predominantly found in the animal's gut. Finally, we show that this skin microbiome promotes host cuticle integrity in harsh environments. Together, we identify a skin microbiome for the well-studied nematode model and propose its value in conferring host fitness advantages in naturalized contexts.

Importance: The genetic model organism has recently emerged as a tool for understanding host-microbiome interactions. Nearly all of these studies either focus on pathogenic or gut-resident microbes. Little is known about the existence of native, nonpathogenic skin microbes or their function. We demonstrate that members of a modified model microbiome, mCeMbio, can adhere to the animal's cuticle and confer protection from noxious environments. We combine a novel micro-swab tool, the first 16S microbial sequencing data from relatively unperturbed , and physiological assays to demonstrate microbially mediated protection of the skin. This work serves as a foundation to explore wild skin microbiomes and use as a model for skin research.