The Immense Functional Attributes of Maize Rhizosphere Microbiome: A Shotgun Sequencing Approach

Saheed Akinola,Ayansina Ayangbenro,Olubukola Babalola

doi:10.3390/agriculture11020118

Abstract

The northwest (NW) province of South Africa is a semi-arid area, often disturbed by soil extremes such as drought and intense temperature. However, many functions possessed by the rhizosphere microbiome are still required, especially those inhabiting arid and semi-arid soils. This study involves a metagenomic comparison of the major metabolic attributes of two maize rhizosphere soils and their surrounding soils. Here, we hypothesized that there is a considerable difference between the functional diversity of maize rhizosphere and bulk soils and that the rhizosphere soil has distinct functional traits of agricultural importance. A high-throughput sequencing approach was used to assess the metabolic profile of rhizosphere soil microbiota of maize collected from the Gauteng and NW provinces of South Africa. The relative abundance of 13 functional hit categories was significantly different between the sampling sites. The diversity indices showed a considerable difference between the rhizosphere and surrounding soils. The difference in the chemical properties of the sampling sites was responsible for the variation in the microbial functional composition. Nevertheless, the presence of a high relative abundance of functional categories with unknown functions in SEED subsystem-2 coupled with the large number of functional hits conferring a response to soil stressors viz. oxidative stress, heat shock, osmotic stress, and cold shock noticed in the rhizosphere samples may indicate the presence of novel genes at the sampling sites. Exploring the plant growth-promoting traits of microorganisms present at these sites could eliminate the constraint posed by soil stressors on sustainable agriculture.

Highlights

Published: 2 February 2021Rhizosphere microorganisms occupy the area surrounding a plant’s roots and are influenced by complex activities associated with the host plant, such as root exudates [1].Root exudates are compounds such as sugars, acids, peptides, amino acids, secondary metabolites, and organic compounds that influence the chemical and biological activities in the soil surrounding the plant
This study successfully compared the functional features of maize rhizosphere and bulk soils rhizobiome and likewise identified soil edaphic factors as an important predictor of soil functioning
The α-diversity of the functional hits showed no significant difference within the samples, while β-diversity indicated that assessed functional categories differed between the sampling area

Summary

Introduction

Rhizosphere microorganisms occupy the area surrounding a plant’s roots and are influenced by complex activities associated with the host plant, such as root exudates [1]. Root exudates are compounds such as sugars, acids, peptides, amino acids, secondary metabolites, and organic compounds that influence the chemical and biological activities in the soil surrounding the plant. The number of important soil microbiota increases as a result of organic compound secretion; the richness of this environment instigates a complex interplay among organisms, resulting in either beneficial, neutral, or harmful effects on the plant. The soil microbiome influences the environment of plants differently; for instance, an ecosystem dominated by bacteria is known for attributes such as high nutrient availability, a neutral to mildly acidic pH, and low organic material content because of high

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