Structural diversity of bacterial communities in two divergent sunflower rhizosphere soils

Abstract

Abstract Purpose Farming practices on farmlands aim to improve nutrients in the fields or crops, soil quality and functions, as well as boost and sustain crop yield; however, the effect of loss of ecological diversity and degradation have impacted ecosystem functions. The beneficial rhizosphere-microorganism network and crop rotation may enhance a stable ecosystem. The use of next-generation sequencing technique will help characterize the entire bacterial species in the sunflower rhizosphere compared with the nearby bulk soils. We investigated the potential of the bacterial community structure of sunflower rhizosphere and bulk soils cultivated under different agricultural practices at two geographical locations in the North West Province of South Africa. Methods DNA was extracted from rhizosphere and bulk soils associated with sunflower plants from the crop rotation (rhizosphere soils from Lichtenburg (LTR) and bulk soils from Lichtenburg (LTB) and mono-cropping (rhizosphere soils from Krayburg (KRPR) and bulk soils from Krayburg (KRPB) sites, and sequenced employing 16S amplicon sequencing. Bioinformatics tools were used to analyse the sequenced dataset. Results Proteobacteria and Planctomycetes dominated the rhizosphere, while Firmicutes and Actinobacteria were predominant in bulk soils. Significant differences in bacterial structure at phyla and family levels and predicted functional categories between soils (P < 0.05) across the sites were revealed. The effect of physicochemical parameters was observed to influence bacterial dispersal across the sites. Conclusion This study provides information on the predominant bacterial community structure in sunflower soils and their predictive functional attributes at the growing stage, which suggests their future study for imminent crop production and management for enhanced agricultural yields.