Compositional shifts in rhizobacterial communities of Brassica napus under salinity stress

Abstract

Salinity stress severely limits crop production globally. The plant rhizosphere harbors diverse microbial communities that can positively influence plant growth and stress tolerance. Therefore, we examined the rhizosphere bacterial populations of Brassica napus under normal and saline conditions using high-throughput 16S rRNA gene sequencing. The objectives were set to identify key taxa enriched in the rhizosphere and evaluate variations in community structure between control and salt-stressed Brassica napus plants. Proteobacteria, Actinobacteria, Chloroflexi, and Bacteroidetes were the predominant phyla. Key genera enriched in the rhizosphere included Sphingomonas, Streptomyces, Bacillus, and Pseudomonas. Salinity stress increased the abundances of Chloroflexi and Acidobacteria while decreased Actinobacteria. Rhizosphere communities of salt-treated plants showed lower diversity but separate clusters from controls, indicating salinity-induced shifts. Predictive functional analysis revealed that amino acid/carbohydrate metabolism and membrane transport pathways in salt-stressed rhizospheres were elevated. This study provides novel insights into the rhizosphere bacteriome of Brassica napus under salinity, highlighting potential plant-growth-promoting taxa for stress amelioration.