AUTHOR=Omotayo Oluwadara Pelumi , Igiehon Ozede Nicholas , Babalola Olubukola Oluranti 

TITLE=Microbial Genes of Agricultural Importance in Maize Rhizosphere Unveiled Through Shotgun Metagenomics

JOURNAL=Spanish Journal of Soil Science

VOLUME=Volume 12 - 2022

YEAR=2022

URL=https://www.frontierspartnerships.org/journals/spanish-journal-of-soil-science/articles/10.3389/sjss.2022.10427

DOI=10.3389/sjss.2022.10427

ISSN=2253-6574

ABSTRACT=Genes possessed by microbes in the rhizosphere influences the metabolic activities that occurs in this zone. Although the maize rhizosphere has been reported to be a hotspot of genes, these genes remains less investigated. Hence, this study aimed at identifying putative microbial genes with plant beneficial functions in the underexplored maize rhizosphere microbiome using shotgun metagenomics approach. Sampling was done in at the flowering stage of the maize plants and both the rhizosphere and bulk soils were collected in triplicates. The metagenomes of the examined rhizosphere and bulk soils revealed genes involved in carbon fixation, nitrogen fixation, iron acquisition, heat and cold shock, phosphorus solubilization and utilization, sulfur cycling and siderophore production. The beta diversity analysis showed significant variations (p<0.05) in these genes across the examined rhizosphere and bulk soils which was further confirmed by the distinct separations between the samples as seen on the principal coordinate analysis (PCoA) plot. Contrarily, no significant difference was observed in diversity within the habitats (p = 0.99). The predominance of significant genes of agricultural importance such as the nifH, nifA, groES and cspA in the rhizosphere metagenomes signifies that this region is endowed with beneficial organisms with potentials in improving plant growth, mitigating stress and reducing the effect of extreme temperatures, which can be optimized in developing biofertilizers. Therefore, development of strategies that will help in cultivating these organisms, which are mostly unculturable, is encouraged. This would make them readily available for use as bio-inoculants and in other biotechnological applications 

Keywords: Maize rhizosphere; Microbes; Microbial genes; Sulfur cycling; Iron acquisition; Rhizosphere microbiome; Heat and cold shock; Shotgun metagenomics