Bradyrhizobium sp nov associated to Acacia saligna
Acacia saligna, a leguminous plant known for its ability to thrive under challenging environmental conditions, plays an important role in bioremediation by enhancing soil fertility and facilitating pollutant degradation. In this study, three slow-growing rhizobial strains, designated 1.29L, 1.27L, and 5.13L, were isolated from root nodules of A. saligna growing naturally in two contaminated sites in Tunisia. A polyphasic taxonomic approach was applied. Phylogenetic analysis based on the 16S rRNA gene placed the isolates within the genus Bradyrhizobium, clustering within the Bradyrhizobium japonicum superclade. Multilocus sequence analysis (MLSA) using concatenated housekeeping genes (recA, atpD, glnII, and gyrB; 1,734 bp) positioned the strains as a distinct lineage, with Bradyrhizobium arachidis, Bradyrhizobium stylosanthis, and Bradyrhizobium shewense as the closest relatives, sharing 94.5–94.8% sequence identity