Intestine regeneration in the sea cucumber Apostichopus japonicus is a
fascinating biological event and a typical example for studying
host-intestinal microbiota interactions. The intestinal microbiota may
play important roles in developing intestine promotion, but the
underlying mechanism remains unclear. Notably, altered microbiota
abundance may be a key marker of the observed ecosystem. To understand
the role of the developing intestinal microbiota in intestine
regeneration via quantitative data, we developed a germ-free sea
cucumber model and analyzed the intestinal microbial differentiation of
faster and slower regenerating A. japonicus individuals during intestine
regeneration. The results revealed that depletion of the intestinal
microbiota resulted in elevated abundance of the potential key players
Flavobacteriaceae and Rhodobacterales during intestine regeneration and
thus promoted the intestine regeneration rate of A. japonicus. These
results first revealed a direct link between intestinal microbial
quantity and microbiome features and the intestinal regrowth rate of A.
japonicus. Metagenomic analysis revealed that the increased abundance of
Flavobacteriaceae elevated the enrichment of genes associated with
carbohydrate utilization, whereas the abundant Rhodobacteraceae
-enriched genes were associated with polyhydroxybutyrate production. We
identified microbiota abundance as a key driver of microbial community
alterations, especially beneficial microbiota members, in the developing
intestine of A. japonicus. This study provides new insights into the
mechanism of host-microbiota interactions related to intestine
development, and the understanding of molecular diversity to questions
within intestinal ecology.