Biofertilization containing Paenibacillus triticisoli BJ-18 alters the composition and interaction of the protistan community in the wheat rhizosphere under field conditions.

Aims: Most studies focus on the effects of biofertilizer on the bacterial and fungal communities, and we still lack an understanding of biofertilizer on the protistan community. Here, the effects of biofertilizer containing Paenibacillus triticisoli BJ-18 on composition and interaction of the protistan community in the wheat rhizosphere were investigated.

Methods And Results: Biofertilizer application altered soil physicochemical properties and the protistan community composition, and significantly induced an alpha diversity decline. Random forecast and redundancy analysis demonstrated that nitrogenase activity and available phosphorus were the main drivers. Trichomonas classified to the phylum Metamonada was enriched by biofertilizer, and was significantly positive connected with soil nitrogenase activity and some function genes involved in nitrogen-fixation and nitrogen-dissimilation. Biofertilization loosely connected biotic interactions, while it did not affect the stability of the protistan community. Besides, biofertilizer promoted the connections of protists with fungi, bacteria, and archaea. Combined with biotic networks (protists, fungi, bacteria, and archaea) and interactions between protists and soil physicochemical properties/function genes, protists may act as keystone taxa potentially driving soil microbiome composition and function.

Significance And Impact Of The Study: Overall, these results suggest that the biofertilizer is a driver of the soil protistan community, contributing to ecosystem functioning.