How the plastisphere mediated by the residual microplastic
film
in farmlands affects microhabitat systems is unclear. Here, microbial
structure, assembly, and biogeochemical cycling in the plastisphere
and soil in 33 typical farmland sites were analyzed by amplicon sequencing
of 16S rRNA genes and ITS and metagenome analysis. The results indicated
that residual microplastic film was colonized by microbes, forming
a unique niche called the plastisphere. Notable differences in the
microbial community structure and function were observed between soil
and plastisphere. Residual microplastic film altered the microbial
symbiosis and assembly processes. Stochastic processes significantly
dominated the assembly of the bacterial community in the plastisphere
and soil but only in the plastisphere for the fungal community. Deterministic
processes significantly dominated the assembly of fungal communities
only in soil. Moreover, the plastisphere mediated by the residual
microplastic film acted as a preferred vector for pathogens and microorganisms
associated with plastic degradation and the nitrogen and sulfur cycle.
The abundance of genes associated with denitrification and sulfate
reduction activity in the plastisphere was pronouncedly higher than
that of soil, which increase the potential risk of nitrogen and sulfur
loss. The results will offer a scientific understanding of the harm
caused by the residual microplastic film in farmlands.