The biodiversity of eukaryotes in Bambara groundnut rhizosphere

Abstract

Bambara groundnut has been observed to resist pest and drought, and still able to produce enormous yield when cultivated on poor soil. The advantages of the crop to farmers includes the fact that it produces enormous yield with very low agricultural input. The aim of the present study was to determine the taxonomic and microbial diversity, and identification of eukaryotic organisms in Bambara groundnut rhizosphere using microbiomeanalyst platform. A total of ten soil samples corresponding to the different growth stages were collected from Bambara groundnut rhizosphere over interval period of 4 weeks at North-West University agricultural farm, Mafikeng campus. These samples were assessed for the presence of eukaryotic organisms through polymerase chain reaction (PCR) of 16S ribosomal ribonucleic acid (rRNA) gene. Metagenomics analysis using culture-independent technique (next generation sequencing (NGS)) by Paired end illumina-Miseq technology sequencing with the prospect of discovering novel eukaryotes with plant growth promoting features was used. Statistical analysis was carried out to profile and confirm identities of detected organisms. Fifty-nine (59) features were detected from the 10 samples by microbiomeanalyst under data normalization and data cleaning. Taxonomic analysis showed that, 69% of the eukaryotes in the samples were Peronosporales while Thalassiosiraceae and others were 30% and 1% respectively. There was profound variance difference in the rhizosphere microbiome mainly at the OTU level which largely attributed to those taxa most strongly depleted by the plant. Thalassiosira pseudonana, which is a centric diatom found in marine environment was observed in this study. This is the first time so far that T. pseudonana is observed in plants rhizosphere and its ability to withstand harsh environmental variation might contribute to the ability of Bambara groundnut to be able to withstand drought, pests and diseases.