Unveiling the bacterial community structure and soil properties in bulk and rhizospheric compartments of Tamarix gallica from an arid Algerian saline ecosystem

Abstract

Soil salinization is among the most critical threats to agriculture and food security, particularly in arid and semi-arid regions. Despite their ecological and agricultural significance, the microbial processes in saline soils of arid regions remain poorly characterized. This first 16S rRNA amplicon-based study of Algerian saline soils examines bacterial communities and physico-chemical properties in the Naama salt flat, focusing on both bulk and rhizosphere soils associated with Tamarix gallica L. Bacterial diversity and community composition were analyzed through high-throughput 16S rRNA gene sequencing on an Illumina MiSeq platform, and soil parameters, including salinity, nutrients, organic carbon, and water retention were measured. Sequence data were processed with QIIME2, and multivariate analyses were applied to compare soil types and explore correlations between taxa and soil properties. Rhizosphere soils tended towards higher Na+, K+, and Ca2+ levels, whereas bulk soils showed greater phosphorus availability. Bacterial diversity was lower in the rhizosphere, which was characterized by a distinct taxonomic composition, including taxa such as Promicromonospora and Nocardioides potentially involved in nutrient cycling and stress adaptation. Correlation analyses revealed microbial adaptations to salinity and nutrient availability. This study lays the groundwork for developing plant growth-promoting rhizobacteria aiming to combat land degradation and contribute to long-term food security and environmental resilience in arid regions.