C. elegans and its bacterial diet as a model for systems-level understanding of host-microbiota interactions

Abstract

Resident microbes of the human body, particularly the gut microbiota, provide essential functions for the host, and, therefore, have important roles in human health as well as mitigating disease. It is difficult to study the mechanisms by which the microbiota affect human health, especially at a systems-level, due to heterogeneity of human genomes, the complexity and heterogeneity of the gut microbiota, the challenge of growing these bacteria in the laboratory, and the lack of bacterial genetics in most microbiotal species. In the last few years, the interspecies model of the nematode Caenorhabditis elegans and its bacterial diet has proven powerful for studying host-microbiota interactions, as both the animal and its bacterial diet can be subjected to large-scale and high-throughput genetic screening. The high level of homology between many C. elegans and human genes, as well as extensive similarities between human and C. elegans metabolism, indicates that the findings obtained from this interspecies model may be broadly relevant to understanding how the human microbiota affects physiology and disease. In this review, we summarize recent systems studies on how bacteria interact with C. elegans and affect life history traits.

Figure 1

C. elegans and its bacterial diet are both tractable model organisms for studying host-microbiota interactions at a systems-level. C. elegans phenotypes (green) can be screened by RNAi-mediated knock down libraries, or by examining collections of deletion, point, or CRISPR mutants. Bacterial mutant libraries (blue) for certain strains are available from targeted deletion or transposon insertion collections.

Figure 2

The structure of the native microbiome in C. elegans. The most abundant phyla and families are indicated. Phyla are represented by color and families are represented by name. This figure was produced with data from [34].