Metagenomic profiling of rhizosphere microbial community structure and diversity associated with maize plant as affected by cropping systems

Soil microbial diversity is believed to be vital in maintaining soil quality and health. Limited knowledge exists on the impact of cropping systems (mono-cropping and crop rotation) on the diversity of the whole soil microbiome. In this study, we investigated the effects of two cropping systems, namely crop rotation and mono-cropping, on the community structure and diversity of rhizosphere microbiome in the rhizosphere and bulk soil associated with maize plant using shotgun metagenomics. Whole DNA was extracted from bulk, and rhizosphere soils associated with maize plant from the mono-cropping (LT and LTc) and crop rotation (VD and VDc) sites, respectively, and sequenced employing shotgun metagenomics. The results obtained via the Subsystem database showed 23 bacteria, 2 fungi, and 3 archaea most abundant phyla. The major bacterial phyla are Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, Gemmatimonadetes, Acidobacteria, Cyanobacteria, Spirochaetes, Aquificae, Verrucomicrobia, Chloroflexi, Planctomycetes, and Chlorobi. The major fungi phyla observed were Ascomycota and Basidiomycota, while the dominant archaea phyla are Euryarchaeota, Thaumarchaeota, and Crenarchaeota. Our diversity assessment showed that the rhizosphere microbial community was more abundant in the samples from the rotational crop site following VD>VDc>LT>LTc. Alpha diversity showed that there was no significant difference (P>0.05) in the soil microbial communities (P>0.05), while better diversity indicated that a significant difference (P = 0.01) occurred. Taken together, crop rotational practice was found to positively influence the rhizosphere microbial community associated with the maize plant.