Copper oxide nanoparticles slightly affect diversity and metabolic profiles of the prokaryotic community in pecan tree (Carya illinoinensis) rhizospheric soil

The prokaryotic community in the pecan tree (Carya illinoinensis) rhizospheric soil with (clo) and without (non-clo) clover coverage exposed to copper oxide nanoparticles (CuO-NP) was evaluated by 16S rRNA amplicon sequencing. Treatments were applied with CuO-NP at concentrations of 0, 10, 100, and 1000 mg kg−1 soil and maintained for 45 days in microcosms. The analyses indicated that the prokaryotic microbial community of the soils consisted mainly of the phyla Thaumarchaeota, Proteobacteria, Actinobacteria, Bacteroidetes, Acidobacteria and Firmicutes (>80%). In terms of diversity, slight differences were observed between the control groups and their respective treatments and among treatments in both clo and non-clo soils. The community structure analyses showed the orders Caulobacterales, Burkholderiales, Xanthomonadales and Clostridiales significantly abundant (P