Improving plant salt tolerance through Algoriphagus halophytocola sp. nov., isolated from the halophyte Salicornia europaea

<i>Salicornia europaea</i>, commonly known as glasswort, thrives in reclaimed land and coastal areas with high salinity, demonstrating remarkable adaptation to the arid conditions of such environments. Two aerobic, Gram-stain-negative, non-motile, rod-shaped bacterial strains, designated TR-M5^T and TR-M9, were isolated from the root of <i>Salicornia europaea</i> plants. These bacteria exhibit plant growth-promoting and salt tolerance-enhancing abilities, which have not been reported in other species of the genus. Both strains produce indole-3-acetic acid (IAA), a plant growth hormone, and synthesize proline, which functions as an osmoprotectant. Additionally, they possess gelatinase and cellulase activities. Cells grow in temperatures from 4 to 42°C (optimum 25°C), pH levels from 6.0 to 9.0 (optimum 7.0), and NaCl concentrations from 0 to 8.0% (optimum 6.0%). The average nucleotide identity and digital DNA-DNA hybridization values of strain TR-M5^T with the most closely related type strains for which whole genomes are publicly available were 74.05-77.78% and 18.6-23.1%, respectively. Phylogenetic analysis of their 16S rRNA gene sequences revealed that strains TR-M5^T and TR-M9 belong to the genus <i>Algoriphagus</i>. <i>A. locisalis</i> exhibited the highest similarity, sharing a sequence identity of 98.1%. The genomes of TR-M5^T and TR-M9 exhibit a G + C content of 43 mol%. This study specifically focuses on the identification and characterization of strain TR-M5^T as a novel species within the genus <i>Algoriphagus</i>, which we propose to name <i>Algoriphagus halophytocola</i> sp. nov., highlighting its potential role in enhancing plant growth and salt tolerance in saline environments. The type strain is TR-M5^T (KCTC 92720^T = GDMCC 1.3797^T).