Background: The gut microbiota of Caenorhabditis elegans, a tiny worm that feeds on bacteria, is significantly dominated by the bacteria upon which it feeds. These bacteria may not only interfere with the intestinal flora of C. elegans but also assist in resisting pathogen infection. Understanding the interactions between the microbiota of C. elegans and pathogens will shed light on how to achieve biological control of agricultural pests.
Results: The lifespan of Caenorhabditis elegans fed on strain CPCC 101271T was extended by approximately 40% compared with that of worms fed on Escherichia coli OP50. In addition, the colonization of C. elegans by the pathogenic bacterium Bacillus nematocida B16 was inhibited when it was pre-fed with strain CPCC 101271T. Based on a polyphasic taxonomy study including genotypic, chemotaxonomic and phenotypic characteristics, we propose that strain CPCC 101271T represents a novel bacterial species with the name Stenotrophomonas nematodicola sp. nov. and CPCC 101271T as the type strain. Metagenomic sequence analysis of the intestinal microbiota of C. elegans fed with strain CPCC 101271T and then infected with B16 revealed that pre-feeding with CPCC 101271T improved the diversity of intestinal bacteria, while the community structure varied significantly together with the fluctuation of Stenotrophomonas spp. and Bacillus spp. abundance during competition between strain CPCC 101271T and B16.
Conclusions: The nematode microbiota strain CPCC 101271T assisted in its host resistance to the pathogen Bacillus nematocida colonization, so as to act as an intestinal life span-prolonging bacterium for C. elegans. The genotypic and phenotypic properties of strain CPCC 101271T supported to the proposal of strain CPCC 101271T as a novel species of the genus Stenotrophomonas.