Soil macrofauna mucus bacterial community: Insights from cultured earthworms and snails

Abstract

The mucus-associated microbiome of soil fauna plays a critical role in host health and ecosystem functioning, but the information of mucus microbiota remains largely unexplored. Here, this study investigated bacterial communities of four soil fauna species (earthworm Eisenia fetida, Metaphire guillelmi; snails Cathaica fasciola, Lissachatina fulica) after 28 days of standardized cultivation. A diverse bacterial community was identified in the mucus of earthworms and snails, dominated by Proteobacteria (53.2%), followed by Bacteroidetes (15.2%), and Actinobacteria (11.9%) at the phylum level. Compared to the surrounding soil, the mucus harbors distinct bacterial communities with lower bacterial diversity. 0.5% of amplicon sequence variants (ASVs) were shared among the mucus, gut, and soil samples, with L. fulica harboring the most unique ASVs (1896). Furthermore, co-occurrence network analysis suggested predominantly positive bacterial interactions, indicating potential cooperative relationships within the host-associated community. Our study indicates that soil fauna mucus environment serves as a bacterial filter, and its community composition is shaped by host habits. These findings advance our understanding of mucus-associated microbes of soil fauna.

Graphical abstract

Keywords

earthworm / snail / mucus microbiota / gut microbiota / network

Highlight

	● The earthworm and snail mucus harbored a rich and diverse bacterial community.
	● Earthworm and snail mucus bacterial communities are significantly distinct from that of the gut and surrounding soil.
	● Unique and shared ASVs were recorded across the mucus, gut, and soil samples.
	● Co-occurrence network analysis showed predominantly positive bacterial interactions across all samples.

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