Metagenomic Study of Bacteria Diversity and Functional Profile in Bulk and Rhizosphere Soils of Fusarium-Wilt Infected Plantain (Musa paradisiaca)

Abstract

Soil contains a great diversity of microorganisms, including bacteria which are known to be drivers of soil ecosystem functions. This study was aimed at investigating the bacterial communities in bulk and rhizosphere soil of Fusarium wilt-infected plantain (Musa paradisiaca). Physicochemical analysis revealed that electrical conductivity (312 µS/cm), cation exchange capacity (15.62 meq/100g), phosphate (0.16 mg/kg), nitrogen (1.53 mg/kg), moisture (19.45 mg/kg), potassium (1.39 mg/kg), magnesium (0.61 mg/kg), clay (60 %), and silt (35%) were higher in bulk soil than rhizosphere soil. The 16S rRNA metagenomic sequences quantified a total of 89341 bacterial taxonomic units from bulk soil which consist of 10 phyla, 13 classes, 16 orders, 18 families, 21 genera, and 19 species. A total of 88034 bacterial taxonomic units which comprised of 9 phyla, 13 classes, 23 orders, 22 families, 26 genera, and 25 species, were found in rhizosphere soil. The most abundant phyla in bulk soil are Actinobacteria (31%), Proteobacteria (26%), and Gemmatimonadetes (17%) Acidobacteria (17%) and Planctomycetes (3%) while the prominent phyla in rhizosphere soil are Actinobacteria (63%) Proteobacteria (24%), Acidobacteria (7%) and Planctomycetes (3%). The major functional profiles of bacterial communities in both bulk and rhizosphere soils are metabolism of amino acids, carbohydrates, terpenoids, polyketides, cofactors, and xenobiotic degradation. Alpha diversities among the bacterial community were higher in Simpson’s reciprocal index for both bulk and rhizosphere soils. This study opens up new frontiers in expanding metagenomics studies on environmental samples which would capture and contribute to the identification of soil bacteria useful to ecosystem functions.