Comparative genomic analyses of the genus Robertmurraya and proposal of the novel species Robertmurraya mangrovi sp. nov., isolated from mangrove soil

Abstract

A Gram-positive, aerobic, motile, rod-shaped bacterial strain, designated 31A1R^T, was isolated from the mangrove soil of Xilian village, Zhanjiang, China. Strain 31A1R^T thrives at temperatures ranging from 15 to 45 °C (optimum at 30 °C), pH 6.5–10 (optimum at 8.5), and in the presence of 0–5% (w/v) NaCl (optimum at 1.5%). The strain shares the highest 16S rRNA gene sequence similarity with Robertmurraya crescens (97.24%) and Robertmurraya dakarensis (97.18%). The complete genome of strain 31A1R^T spans 4.71 Mbp with a genomic DNA G + C content of 35.9 mol%. The average nucleotide identity and DNA–DNA hybridization values between strain 31A1R^T and type strains of other species of the genus Robertmurraya were 71.24–72.11% and 19.90–21.40%, respectively. The amino acid identity values and percentage of conserved proteins ranged from 66.94 to 68.10% and from 58.34 to 61.62%, respectively, aligning with intrageneric cutoff values. The major fatty acids (≥ 5.0%) were iso-C_14:0 (5.0%), iso-C_15:0 (41.4%), iso-C_16:0 (12.6%), C_16:1ω7c alcohol (12.2%), and iso-C_17:1 ω10c (6.5%). The polar lipids profile was mainly composed of diphosphatidyl glycerol, phosphatidyl glycerol, and phosphatidyl ethanolamine. We also profiled the pan-genome and metabolic features of genomic assemblies of strains belonging to the genus Robertmurraya, which indicated functional capacities and metabolic similarities. Consequently, we propose that strain 31A1R^T represents a new species in the genus Robertmurraya, for which the name Robertmurraya mangrovi sp. nov. is proposed, with the type strain being 31A1R^T (= GDMCC 1.4378^T = JCM 36937^T).