Distinct Polysaccharide Utilization as Determinants for Interspecies Competition between Intestinal Prevotella Spp

Prevotella spp. form one of the most dominant bacterial genera in the human gut. Multiple Prevotella spp. can co-exist in some but not all individuals consuming plant-based diets. To functionally investigate the relationship between Prevotella competition and diet, we isolated several novel Prevotella spp. from the mouse gut, performed genome and metatranscriptome analysis as well as a series of competition experiments under different dietary conditions. These experiments revealed that diverse dominant Prevotella species compete for similar metabolic niches in vivo, which is linked to the upregulation of specific Polysaccharide Utilization Loci (PULs). Complex plant-derived polysaccharides are required, and particularly arabinoxylan is sufficient, for the expansion of Prevotella spp. The most dominant Prevotella species encodes a specific tandem-repeat trsusC/D PUL, which is conserved in highly abundant Prevotella copri strains further expanded in humans consuming a vegan diet. Our data suggest efficient (arabino)xylan-utilization as a factor contributing to Prevotella dominance.