Caenorhabditis microbiota: worm guts get populated

Abstract

Until recently, almost nothing has been known about the natural microbiota of the model nematode Caenorhabditis elegans. Reporting their research in BMC Biology, Dirksen and colleagues describe the first sequencing effort to characterize the gut microbiota of environmentally isolated C. elegans and the related taxa Caenorhabditis briggsae and Caenorhabditis remanei In contrast to the monoxenic, microbiota-free cultures that are studied in hundreds of laboratories, it appears that natural populations of Caenorhabditis harbor distinct microbiotas.

Fig. 1.

Sequencing bacterial 16S rRNA genes from the worm gut. Adult C. elegans showing pharyngeal structures (dark grey) and gut (light grey) containing live microorganisms. The pharyngeal grinder disrupts E. coli cells under most laboratory conditions but in natural environments many microbes survive passage through the pharynx. Total DNA is extracted and the V4 variable region of the 16S ribosomal RNA gene is amplified by PCR prior to sequencing

Fig. 2.

The C. elegans lifecycle. Eggs hatch and go through four larval stages (L1–L4) before adulthood. An alternative non-feeding larval stage (Dauer) can be initiated at the L2 moult in conditions of high population density, temperature, or starvation and worms can also arrest at the L1 larval stage under starvation conditions. Adapted from [6]