Pseudomonas retamae sp. nov., a novel endophytic bacterium with plant growth-promoting potential, isolated from root nodules of Retama monosperma in Northwestern Algeria

• DOI: 10.1099/ijsem.0.006646
• Publication Date: 2025-01-15T15:18:02Z
• Authors: Nawel Selami; Fatima El-Houaria...; Chahira Zerouki; Chahrazed Aibeche; Nassima Draou; Omar Khelil; Slimane Choubane; Makaoui Maatallah; Ikram Madani; Khadidja Ouenzar; Assia Zemmour; Mohamed Kerkoud; Bacem Mnasri; Bouziane Moumen; Cécile Vriet; Abderrezak Djabeur
• Keywords: Housekeeping gene; Strain (injury); Genome size; genomic DNA

A thorough polyphasic taxonomic study, integrating genome-based approaches, was carried out to characterize the RB5 T strain isolated from root nodules of Retama monosperma growing on coastal dunes Bousfer Beach (Oran, Algeria). The 16S rRNA gene sequence analysis revealed that had highest similarity Pseudomonas granadensis LMG27940 (98.94%) and gozinkensis IzPS32d (98.73%). Phylogenetic studies, including both multilocus using , gyrB rpoD housekeeping genes, positioned in a distinct branch alongside its closest relative, P. . Phylogenomic Bac120 marker set Type (Strain) Genome Server confirmed unique position close relationship with Similarly, genomic comparisons average nucleotide identity based blast (ANIb) digital DNA–DNA hybridization (dDDH) values 92.85 59.3%, respectively, when compared Both fall below established species delimitation thresholds 95–96% for ANIb 70% dDDH, providing strong evidence represents novel species. Further unclassified spp. (384 genomes) metagenomic-derived genomes Taxonomy Database (GTDB) showed between 84.27 89.2%, indicating belongs evolutionary line. genome size 6 311 310 bp G+C content 60%, harbours several key genes associated plant growth-promoting traits, making it promising candidate sustainable agriculture. Phenotypically, is an aerobic, rod-shaped, Gram-negative, non-spore-forming bacterium motile single polar flagellum. It grows under wide range temperature (4–42 °C) pH (5–10) conditions tolerates up 6% (w/v) NaCl. main cellular fatty acid composition includes C 16:0 17:0 cyclo summed features 3 consisting 16:1 ω7c/ C16:1 ω6c. Based phylogenetic, phenotypic, chemotaxonomic comparison analyses, identified as genus which name retamae sp. nov. proposed. type (=DSM 117471 =LMG 33633 =CIP 112482 ).