Characterization of Saccharothrix sabaoui sp. nov., isolated from vineyard soil collected in Mostaganem, Algeria

A novel strain, designated Mg75^T, was isolated from a vineyard soil sample collected in Mostaganem, Algeria. This Gram-positive, non-motile strain produces a branched, fragmented substrate mycelium with a yellowish-orange colour and a white aerial mycelium on International Streptomyces Project 2 (ISP2), ISP3 and ISP4. Mg75^T exhibited growth across a temperature range of 15-40 °C, with an optimal range of 28-30 °C. It thrived at pH levels between 5.0 and 10.0, with an optimum at pH 7.0, and tolerated NaCl concentrations ranging from 0% to 3% (w/v), with an optimal concentration range of 0-1% (w/v). Phylogenetic analysis based on the 16S rRNA gene sequence indicated the highest similarity with Saccharothrix yanglingensis Hhs.015^T (98.95%). The G+C content of the genomic DNA of strain Mg75^T was 73.4 mol%. Digital DNA-DNA hybridization (dDDH) between strain Mg75^T and its neighbouring Saccharothrix species ranged from 23.2% to 39.9%. Average nucleotide identity (ANI) ranged from 82.08% to 90.91%, and average amino acid identity (AAI) ranged from 79.8% to 92.57%, way below the thresholds of 70% for dDDH and 95-96% for ANI and AAI used for species delimitation. Strain Mg75^T was found to share a similar chemotaxonomic profile based on genomic chemotaxonomic markers. The phylogenetic and phylogenomic analyses, together with the in silico chemotaxonomic and phenotypic data, indicated that strain Mg75^T (=DSM 118769^T=CECT 31160^T) represented a novel species of the genus Saccharothrix, for which the name Saccharothrix sabaoui sp. nov. is proposed.