# Assessment of Bacterial Diversity and Rhizospheric Community Shifts in Maize (Zea mays L.) Grown in Soils with Contrasting Productivity Levels

## TL;DR

This study explores how soil productivity affects bacterial communities in maize, finding that certain microbes and their interactions may influence soil health and crop yield.

## Contribution

The study identifies specific microbial genera and interactions that correlate with soil productivity in maize cultivation.

## Key findings

- Genera like Priestia and Neobacillus decreased in the rhizosphere of non-productive soils.
- Rhizobium–Bradyrhizobium associations were positive across soils, while Neobacillus and Priestia were negative.
- Soil type, not compartment, was the main driver of microbial community clustering.

## Abstract

The resident microbiota in agricultural soils strongly influences crop health and productivity. In this study, we evaluated the prokaryotic diversity of two clay soils with similar physicochemical characteristics but contrasting levels of maize (Zea mays L.) and wheat (Triticum aestivum L.) production using 16S rRNA gene sequencing. Yield records showed significant differences in grain production over five consecutive years. When comparing prokaryotic alpha diversity between the “non-productive” and “productive” soils, no major differences were found, and the abundance of ammonia-oxidizing archaea (AOA) and bacterial genera such as Arthrobacter, Neobacillus, and Microvirga remained consistent across soils. Analysis of the top 20 genera showing the greatest abundance shifts by compartment (bulk soil vs. rhizosphere) revealed that genera such as Priestia, Neobacillus, Sporosarcina, and Pontibacter decreased in the rhizosphere of the non-productive soil, while in the productive soil, these genera remained unchanged. In the non-productive soil, genera such as Flavisobacter decreased in abundance in the rhizosphere, whereas Arthrobacter increased. Principal coordinates analysis (PCoA) showed no clear clustering by compartment (bulk vs. rhizosphere), but two distinct clusters emerged when grouping by soil type (productive vs. non-productive). Interaction networks varied by soil type: non-productive soils showed positive Candidatus–Bacillus and negative Massilia links, while productive soils were dominated by Flavisolibacter and negative Pontibacter. Across soils, Rhizobium–Bradyrhizobium associations were positive, whereas Neobacillus and Priestia were negative. These findings highlight that a few potential beneficial microbiota and their interactions may be key drivers of soil productivity, representing targets for microbiome-based agricultural management.